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Subsidiary Mathematics for Rwanda Secondary Schools Teacher’s Guide Senior Five FOUNTAIN PUBLISHERS www.fountainpublishers.co.ug Authors Ngezahayo Emmanuel Icyingeneye Pacifique

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Page 1: Subsidiary Mathematics - Rwanda Education Board Right Textbooks for Web... · 2020. 1. 22. · Subsidiary Mathematics Teacher’s Guide Book Five vi with instruction. Formative assessment

Subsidiary Mathematics

for Rwanda Secondary Schools

Teacher’s Guide

Senior Five

FOUNTAIN PUBLISHERSwww.fountainpublishers.co.ug

Authors

Ngezahayo Emmanuel

Icyingeneye Pacifique

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Fountain Publishers Rwanda Ltd

P.O. Box 6567

Kigali, Rwanda

E-mail: [email protected] [email protected]; [email protected]: www.fountainpublishers.co.ug

© Ngezahayo Emmanuel, Icyingeneye Pacifique 2017

First Published 2017

All rights reserved no part of this book may be reproduced, stored

in a retrieval system, or transmitted in any form or by any means;

electronic, mechanical, photocopying, recording or otherwise without

prior written permission from the authors and the publishers.

ISBN: 978-9970-19-413-1

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iii

Contents

Section 1: General introduction ............................................. vSection 2: Effective tips for brighter learners .........................viiiSection 3: Effective tips for slow learners ..............................viiiSection 4: Extension knowledge and ideas for teachers ............ xSection 5: Content map ......................................................xiiiSection 6: Example of Lesson plan ........................................xxSection 7: General Methodology ......................................... xxviSection 8: Units description .............................................. xxvi

Unit 1 Trigonometric Formulae and Equations ........................... 11.1. Trigonometric formulae ....................................................1

1.2. Trigonometric equations .................................................11

1.3. Applications ...................................................................16

Unit 2 Sequences................................................................. 192.1. Arithmetic sequences and harmonic sequences ..............19

2.2. Geometric sequences .....................................................26

2.3. Applications ...................................................................32

Unit 3 Logarithmic and Exponential Equations ........................ 353.1. Exponential and logarithmic functions ...........................35

3.2. Exponential and logarithmic equations ...........................38

3.3. Applications ...................................................................42

Unit 4 Trigonometric Functions and their Inverses ................... 454.1. Generalities on trigonometric functions and

their inverses ..................................................................46

4.2. Limits of trigonometric functions ...................................54

4.3. Differentiation of trigonometric functions and

their inverses ..................................................................58

4.4. Applications ...................................................................66

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Subsidiary Mathematics Teacher’s Guide Book Five

iv

Unit 5 Vector Space of Real Numbers .................................... 695.1. Scalar product of two vectors .........................................69

5.2. Magnitude (or norm or length) of a vector ......................71

5.3. Angle between two vectors ..............................................71

5.4. Vector product ...............................................................73

5.5. Applications ...................................................................76

Unit 6 Matrices and Determinant of Order 3 ........................... 836.1. Square matrices of order three .......................................83

6.2. Determinant of order three .............................................91

6.3. Applications ...................................................................96

Unit 7 Bivariate Statistics ..................................................... 997.1. Covariance ....................................................................99

7.2. Regression lines ...........................................................101

7.3. Coefficient of correlation ..............................................104

7.4. Applications .................................................................106

Unit 8 Conditional Probability and Bayes Theorem ................ 1098.1. Tree diagram ................................................................109

8.2. Independent events ......................................................112

8.3. Conditional probability .................................................113

8.4. Bayes theorem and applications ...................................115

References ...........................................................................118

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v

Section 1: General introduction

1.1. General introduction to the new curriculum

The curriculum for Rwandan schools at primary and secondary

levels has been changed from knowledge and content bases

to competence based (CBE). CBE is of great importance in

aligning Rwanda’s education to the social and economic

demands of society. It also presents answers to concerns about

the capability and employability of school graduates.

1.2. General guidance to teachers

In Subsidiary mathematics-Learner’s Book Five, there are eight

units. There are many activities to be done by learners before

a new lesson. This will help students to understand well the

lesson.

Teacher must help students to do those activities. Form groups

of at least six students and let them do the activities in those

groups.

At the end of the lesson, there is a series of exercises which

summarise the lesson taught. As teacher, let the students do

those exercises and correct them on chalkboard.

Also, at the end of each unit, there is a series of exercises

which summarise the whole unit.

1.3. List of equipment needed for the subject

Students will need geometric instruments for sketching curves

and scientific calculators for some calculations.

1.4. General guidance on assessment both formative and

summative

Assessment is the use of a variety of procedures to collect

information about learning and instruction. Formative

assessment is commonly referred to as assessment for learning,

in which focus is on monitoring student response to and progress

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Subsidiary Mathematics Teacher’s Guide Book Five

vi

with instruction. Formative assessment provides immediate

feedback to both the teacher and student regarding the learning

process. Formative and summative assessments contribute in

different ways to the larger goals of the assessment process.

Teacher must provide oral or written feedback to students’

discussion or work. For example, a teacher responds orally to

a question asked in class; provides a written comment in a

response or reflective journal; or provides feedback on student

work.

At the end of each lesson, teacher must give to the students

a small evaluation to see if they understood the lesson. Also

at the end of the units, teacher must give the general test

which summarises the whole unit. When assessments reflect

the stated learning objectives, a well-designed end of unit test

provides teachers with information about individual students

(identifying any student who failed to meet objectives), as well

as provides an overall indication of classroom instruction.

Although formative and summative assessments serve different

purposes, they should be used ultimately within an integrated

system of assessment, curriculum, and instruction. To be

effective in informing the learning process, assessments must be

directly integrated with theories about the content, instruction,

and the learning process and must be valid and reliable for the

purposes for which they are used.

1.5. Guidance on grading and reporting

Academic achievement may be measured in a variety of ways,

including compositions, presentations, oral discussion, student

work samples, observations, tests, and the products of project-

based learning activities. Teachers should use the most current

summative assessment data when determining achievement

marks for the progress report. When determining what marks

to use on daily and weekly assignments, remember that these

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Introduction

vii

marks should not conflict with the grades on the progress

report. Teachers should not use letter grades when marking

papers.

Some options may include:

࿌ Raw scores or ratios (11/12 correct)

࿌ Written feedback

࿌ Rubric scores (if using 4, 3, 2, or 1 on papers, there should be guidance as to what these marks mean).

Keep in mind that work that is sent home provides parents with

a general impression of how students are achieving in school

but does not provide a complete picture. Other assessment data

are collected that encompasses the progress report grade and

some of these assessments are not sent home. Communication

regarding progress should be ongoing.

Homework can be considered as part of the effort grade,

but would not be used to grade academic achievement in

elementary school since the function of homework is to provide

practice in skill areas.

Achievement marks will be reported on a 4-point scale and

cannot be equated to former guidelines for letter grades. A grade

of “4” indicates a high level of achievement; it communicates

that a student has a strong understanding of all the concepts

and skills taught for that standard during the quarter and

can demonstrate understanding independently and with very

few errors. When determining grades for students, teachers

should consider the most current assessment data as evidence

of learning. Earlier assessments may no longer be relevant if

students have demonstrated further progress.

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viii

Section 2: Effective tips for brighter learners

Teacher must encourage learners to:

1. explain to each other as best they can the lesson learned.

2. have an Exercise books, homework book and note book

of course.

3. have geometric instruments and scientific calculator.

4. work exercises and homework and check their answers to

gain practice with every lesson.

5. do their own research on learned lessons or lessons to be

learned next time.

Section 3: Effective tips for slow learners

Mathematics may be challenging for a slow learner, but not

impossible. Slow learners also want to learn mathematics, but

lack of learning ability and mathematics education system they

are not able to learn faster. The following are some techniques

which can help slow learners:

1. Slow learners need more time to understand any problem

or to find out the answer. Give extra time to slow learners.

This will increase their confidence. Do not pressurize

learners to perform on time beyond their ability. This will

only decrease confidence.

2. Slow learners need extra attention. With a small students

group, you can effectively respond to each student.

3. Environment is more potent than willpower. Create a fun

environment for learners. Use new learning techniques,

especially for slow learners. Teacher can provide

mathematics games and activities to learners.

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Introduction

ix

4. Build a helpful environment for learners. Encourage

learners to ask questions and let them feel free to ask for

any help.

5. Most slow learners face difficulty to understand the new

concepts. Try to relate the new concepts with previous

concepts. This will help them to catch the new concepts

relatively fast.

6. One of the best ways to teach mathematics not only to

slow learners but even for normal students is, explain

concepts using real life examples.

7. Whenever possible, provide opportunities to show them

their work. Let the students teach you about mathematics.

This will help students to reduce mathematics fear.

8. Because slow learners need more time to understand

the concepts, frequent reviewing can help them out.

Reviewing mathematics concepts time to time will allow

them to master the mathematics concepts.

9. Slow learners tend to have lack of confidence, if you

pressurise them for time management or anything, this

will only reduce their confidence.

10. Slow learners tend to have low confidence. Low confidence

impedes anyone’s learning ability. If you reward them time

to time, this will help them to raise their confidence.

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x

Section 4: Extension knowledge and ideas for teachers

The following are the most important principles in mathematics

teaching.

1.1. Principle 1: Let It Make Sense

Let us strive to teach for understanding of mathematical

concepts and procedures, the “why” something works, and not

only the “how”.

The “how” something works is often called procedural

understanding: the learner knows how to work/solve a linear

equation. It is often possible to learn the “how” mechanically without understanding why something works. Procedures

learned this way are often forgotten very easily.

The relationship between the “how” and the “why” - or between

procedures and concepts - is complex. One doesn’t always

come totally before the other, and it also varies from learner

to learner.

Try alternating the instruction: teach how to solve a linear

equation, and let the learner practice. Then explain why it

works.

As a teacher, don’t totally leave a topic until the student both

knows “how” and understands the “why”.

Teacher can often test a student’s understanding of a topic by

asking him “Tell me an example of where linear equation is

used in daily life.”

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Introduction

xi

1.2. Principle 2: Remember the Goals

Teacher must

࿌ cover the curriculum by the end of school year,

࿌ make sure the learners have a lot formative and summative assessments.

Generally, teacher must

࿌ enable the learners to understand information around us,

࿌ prepare learners for further studies in mathematics,

࿌ let learners see some beauty of mathematics and learn them to like it.

1.3. Principle 3: Know Tools

First of all of course comes a black or white board or paper

— something to write on, then we have pencils, compass,

protractor, ruler, eraser.... and the book the teacher is using.

Then we have computer software, interactive activities,

animated lessons and such. There are workbooks, fun books,

work texts, books, and online tutorials.

Teacher has to start somewhere, probably with the basics,

and then add to his/ her “toolbox” little by little as you have

opportunity. It’s important to learn how to use any tool that

teacher might acquire.

Basic tools1. The board and/or paper to write on. Essential. Easy to use.

2. The learners’ book and teacher’s guide

The extras1. Computer and projector

2. Internet connection

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Subsidiary Mathematics Teacher’s Guide Book Five

xii

If computer lab is available at the school, teacher can show the

learners how ICT is used in mathematics. For example;

࿌ Writing mathematical expression using Microsoft Office Word or other software tools like Math-Type,

࿌ Sketching a function in Cartesian plane using Microsoft Office Excel or other software like Geogebra, Graph, Grapes, …

࿌ Determine the mean, standard deviation, variance,… of a set of data using Microsoft Office Excel formulae or other software like Geogebra, …

࿌ Performing mathematical operations using Microsoft Excel or other software like Mathlab, Geogebra, …

1.4. Principle 4: Living and Loving Mathematics

Mathematics teacher has to ensure that he/she

1. uses mathematics often in daily life,

2. likes mathematics,

3. loves mathematics,

4. is happy to teach mathematics.

Some ideas for teacher: ࿌ Let it make sense. This alone can usually make quite a

difference and learners will stay interested.

࿌ Read through some fun mathematics books. Get to

know some interesting mathematics topics besides just schoolbook arithmetic. There are lots of story books

(mathematics readers) that teach math concepts.

࿌ Consider including some math history if you have the time.

࿌ When you use mathematics in your daily life, explain how you’re doing it, and include the children if possible. Figure it out together.

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xiii

Section 5: Content map

The following table summarises every unit in Learner’s Book.

Unit 1

Trigonometric formulae and

equations

Unit 2

Sequences

Number of

Periods

15+ homework 12+ homework

Introduction The techniques in trigonometry

are used for finding relevance in

navigation particularly satellite

systems and astronomy, naval and

aviation industries, oceanography,

land surveying and in cartography

(creation of maps). Now those are

the scientific applications of the

concepts in trigonometry, but most

of the mathematics we study would

seem (on the surface) to have little

real-life application. Trigonometry

is really relevant in our day to day

activities.

By a sequence, we mean

ordered list having a first

element but not the last.

That means, there is an

order in the numbers; that

is we actually have the first

number, the second number

and so on… A sequence is

a set of real numbers with

natural order.

Classroom

Organisation

Whole class orientation; then

working in pairs or groups.

Whole class orientation;

then working in pairs or

groups.

Equipment

Required

• Instruments of geometry

• Scientific calculator

Scientific calculator

Activities Group work, pairing, research Group work, pairing,

practical, research

Competences

Developed

• Team work

• Creativity

• Research

• Critical thinking

• Team work

• Analysis

Language

Practice

Discussion in group, presentation of

findings

Discussion in groups,

presentation of findings

Vocabulary

Acquisition

Sequence or progression,

arithmetic and geometric

sequence

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Subsidiary Mathematics Teacher’s Guide Book Five

xiv

Study Skills Application of transformation

formulae, solve, explain and

analyze

Analysis, critical thinking

Revision Revision of provided exercises Revision of provided

exercises

Assessments • Formative assessments through

activities.

• Summative assessments

through exercises and end of

unit assessments.

• Formative assessments

through activities.

• Summative assessments

through exercises and

end of unit assessments.

Learning

Outcomes

• Use transformation formula

to simplify the trigonometric

expressions.

• Solve trigonometric equations.

• Solve problems involving

trigonometry concepts.

• The relationship between

trigonometry and other subjects.

• Determine the “nth”

term and the sum of

the first “n”terms of

arithmetic progressions

or geometric progression

• Apply the concepts

of sequences to solve

problems involving

arithmetic or geometric

sequences.

• Relationship between

the sequences and other

subjects.

Unit 3

Logarithmic and Exponential

Equations

Unit 4

Trigonometric Functions

and their inverses

Number of

Periods

15 + homework 12 + homework

Introduction People such as scientists,

sociologists and town planners are

often more concerned with the rate

at which a particular quantity is

growing than with its current size.

The director of education is more

concerned with the rate of at which

the school population is increasing

or decreasing than with what the

population is now, because he has

to plan for the future and ensure

Trigonometry has become

an essential part of today’s

world. There are so many

places where trigonometry

is used, that is impossible to

list them all. For example,

there would be no space

travel, or even air travel

without trigonometry.

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Introduction

xv

that there are enough(and not too many) school places available to meet demand each year. The scientists may need to know the rate at which a colony of bacteria is growing rather than how many of the bacteria exists at this moment, or the rate at which a liquid is cooling rather than the temperature of the liquid now, or the rate at which a radioactive material is decaying rather than how many atoms current exist.The above events show us the areas where this unit finds use in our daily activities.

Classroom

Organisation

Whole class orientation; then

working in pairs or groups.

Whole class orientation;

then working in pairs or

groups.

Equipment

Required

• Instruments of geometry

• Scientific calculator

• Geometric instruments

and graph paper

• Scientific calculator

• Manila papers and

markers

Activities Group work, practical Group work, pairing,

research

Competences

Developed

Solving, Creativity Numeracy, Drawing and

creativity

Language

Practice

Presenting result obtained in

activities.

Presenting result obtained in

activities

Vocabulary

Acquisition

Exponential growth and decay.

Study Skills • Define logarithms and exponentials

• Properties of logarithms and exponentials and their applications

• To model and solve problem involving logarithms

• Convert the logarithm to exponential form

Solving and discussion

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Subsidiary Mathematics Teacher’s Guide Book Five

xvi

Revision Revision of provided exercises Revision of provided exercises

Assessments • Formative assessments through

activities.

• Summative assessments

through exercises and end of

unit assessments.

• Formative assessments

through activities.

• Summative assessments

through exercises and

end of unit assessments.

Learning

Outcomes

• State and demonstrate

properties of logarithms and

exponentials.

• Carry out operations using the

change of base of logarithms.

• Apply logarithms or exponential

to solve problem involving

logarithms such radioactive-

decay problems, Carbon dating

problems, …

• Extend the concepts of function, domain, range, period, inverse function, limits to trigonometric functions.

• Solve problems involving trigonometric functions. Calculation of limits of trigonometric functions and remove their indeterminate forms.

• Calculation of high derivatives of trigonometric functions.

Unit 5

Vector Space of Real Numbers

Unit 6

Matrices and Determinant of

Order 3

Number of

Periods

9+ homework 18+ homework

Introduction A vector space (also called a linear space) is a collection of objects called vectors, which may be added together and multiplied by numbers, called scalars in this context. In physics, vectors are often used to describe forces. Classical Mechanics: Block sliding down a ramp: You need to calculate the force of gravity (a vector down), the normal force (a vector perpendicular to the ramp), and a friction force (a vector opposite the direction of motion).

Matrices play a vital role in the projection of a three dimensional image into a two dimensional image. Matrices and their inverse are used by programmers for coding or encrypting a message. Matrices are applied in the study of electrical circuits, quantum mechanics and optics. A message is made as a sequence of numbers in a binary format for communication and it follows code theory for solving. Hence with the help of matrices, those equations are solved. Matrices are used for taking seismic surveys.

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Introduction

xvii

Classroom

Organisation

Whole class orientation; then

working in pairs or groups.

Whole class orientation; then

working in pairs or groups.

Equipment

Required

Geometric instruments and

graph paper

Scientific calculator

Manila papers and markers

Scientific calculator

Activities Group work, pairing, practical,

research

Group work, pairing

Competences

Developed

Creativity Creativity, data analysis,

communication skills, solve

Language

Practice

Presenting result obtained in

activities.

Presenting result obtained in

activities.

Vocabulary

Acquisition

Geometric interpretation of dot

product and cross product.

• Upper and lower triangular

matrices.

• Adjoint matrix

Study Skills Calculation, discussion,

explanation,

Solving, modeling and creativity

Revision Revision of provided exercises Revision of provided exercises

Assessments • Formative assessments

through activities.

• Summative assessments

through exercises and end

of unit assessments.

• Formative assessments

through activities.

• Summative assessments

through exercises and end of

unit assessments.

Learning

Outcomes

• Dot product and the cross

product of two vectors in

a three dimensional vector

space and their properties.

• Magnitude of a three-

dimensional vector.

• Explain geometrically the

dot product and the cross

product.

• Define operations on matrices

of order 3.

• Apply the properties on

calculation of determinant of

order 3.

• Identify invertible matrix and

determine inverse of matrix of

order 3.

• Apply matrices in solving

related problems

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Subsidiary Mathematics Teacher’s Guide Book Five

xviii

Unit 7

Bivariate statistics

Unit 8

Conditional Probability and

Bayes Theorem

Number of

Periods

12+ homework 15+ homework

Introduction In descriptive statistics data

may be qualitative such

as sex, color and so on or

quantitative represented by

numerical quantity such as

height, mass, time and so

on.

The measures used to

describe the data are

measures of central

tendency and measures of

variability or dispersion.

Until now, we know how

to determine the measures

of central tendency in one

variable. In this chapter, we

will use those measures in

two quantitative variables

known as double series.

Probability is a common

sense for scholars and

people in modern days. It is

the chance that something

will happen-how likely it

is that some event will

happen. No engineer or

scientist can conduct

research and development

works without knowing the

probability theory. Some

academic fields based on

the probability theory are

statistics, communication

theory, computer performance

evaluation, signal and

image processing, game

theory.... Some applications

of the probability theory are

character recognition, speech

recognition, opinion survey,

missile control, seismic

analysis...

Classroom

Organisation

Whole class orientation;

then working in pairs or

groups.

Whole class orientation; then

working in pairs or groups.

Equipment

Required

Instrument of geometry

Scientific calculator

Scientific calculator

Activities Group work, pairing,

research

Group work, pairing

Competences

Developed

Analysis, discussion Analysis, discussion

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Introduction

xix

Language

Practice

Presenting result obtained in

activities.

Presenting result obtained in

activities.

Vocabulary

Acquisition

Bivariate data, covariance,

coefficient of correlation,

regression line

Independent events

Study Skills Explanation, analyze,

calculation, critical thinking

Calculation, explanation,

analysis

Revision Revision of provided

exercises

Revision of provided exercises

Assessments • Formative assessments

through activities.

• Summative assessments

through exercises and

end of unit assessments.

• Formative assessments

through activities.

• Summative assessments

through exercises and end

of unit assessments.

Learning

Outcomes

• Calculate covariance.

• Find regression lines.

• Determine coefficient of

correlation.

• Analyze and interpret

data critically.

• Calculate number possible

outcomes of occurring

independent events

under equally likely

assumptions.

• Compute the probability

of an event B occurring

when event A has already

taken place.

• To use correctly Bayes’s

theorem in solving

problems.

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xx

Section 6: Example of Lesson plan

School: ……………… Academic year: ................…

Teacher’s name: …………

Term Date Subject Class Unit

No

Lesson

No

Duration Class

size

1 …… Mathematics S5

PCB

2 1 of 12 80

minutes

35

Type of Special Educational Needs and number of learners

4 low vision learners: to avail big printed documents and facilitate these learners.

Avoid making a group of low vision only otherwise it can be considered as

segregation.

Gifted learners: to encourage them to explain, to each other and help their

classmates.

Unit title SEQUENCES

Key Unit

Competence:

Understand, manipulate and use arithmetic, geometric

sequences.

Title of the

lesson

Definition and properties of arithmic sequences

Instructional

objective

Given a sequence of numbers, learners should be able to

determine if it is an arithmetic sequence and find out a common

difference of any arithmetic sequence accurately.

Plan for this

Class

Location: Classroom

Learners are organised into groups and they have to do activity

2.1, from Learner’s book page 24, in their groups

Learning

Materials

Exercise books, pen and ruler

References Learners Book

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Introduction

xxi

1.5. Description of teaching and learning activity

In groups, learners will do the activity 2.1 from learner’s book

page 24, make presentation of group findings. In conclusion,

learners will do questions 1 and 2 of exercise 2.1 from learner’s

book page 26 in their respective groups and solve them on

chalkboard. Learners will do question 3 of exercise 2.1 as

individual quiz and questions 4 and 5 will be an assignment. At

the end of the lesson learners are also given another assignment

to be discussed as an activity of the next lesson “General term

of an arithmetic sequence”.

Timing for

each step

Teacher’s

activities

Learners’ activities Competences and

cross cutting issues

to be addressed

Introduction

5 minutes

Ask

questions

on previous

lesson.

Question:

Solve the following equations

1. 2cos

2x =

2. 1sin 22

x =

Respond to questions on the

chalkboard

Answers:

1. 2 ,4

x k kπ π= ± + ∈

2. 12 ,512

kx k

k

π π

π π

+= ∈ +

Students are

developing

communication

skills when they

are explaining and

sharing ideas.

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Subsidiary Mathematics Teacher’s Guide Book Five

xxii

Timing for each step Teacher’s activities Learners’ activities Competences and cross

cutting issues to be

addressed

Body of the lesson

15 minutes

10 minutes

Step 1:

Form groups

• Request the learners to do activity 2.1 from

learner’s book page 24 in their groups

• Goes round to check the progress of the

discussion, and intervenes where necessary.

• Guides learners with special educational

needs on how to do activity.

Step 2:

Request a reporter from each group to present

the work on the chalkboard.

In their groups, learners will do activity 2.1.

On a piece of paper, they will draw a tower

with blocks starting with 15 blocks for the

bottom row until they will not be able to add

another row.

• Reporter represents the work.

• Learners interact through questions and

comments.

Answers a)

b) There are 15 rows

c) 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5,

4, 3, 2, 1

d) Observing this sequence the number

that is added to the number to obtain

the next is -1.

• Cooperation and

interpersonal

management developed

through working in

groups.

• Communication:

learners communicate

and convey information

and ideas through

speaking when they are

presenting their work.

• Self confidence:

learners will gain self

confidence competence

when they are

presenting their work.

• In group activities, the

fact of being convinced

without fighting, peace

and education values

are developed too.

Conclusion

10 minutes

Request learners to give the main points of the

learned lesson in summary.

Summarise the learned lesson:

Sequences of numbers that follow a pattern

of adding a fixed number, called common

difference d, from one term to the next are

called arithmetic sequences or arithmetic

progressions. That is d u un n= −+1 or

d u un n= − −1 . For an arithmetic sequence

1 1, ,n n nu u u− + , we have 2 1 1u u un n n= +− + .

• Learners develop

critical thinking through

generating a summary.

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Introduction

xxiii

Timing for each step Teacher’s activities Learners’ activities Competences and cross

cutting issues to be

addressed

Body of the lesson

15 minutes

10 minutes

Step 1:

Form groups

• Request the learners to do activity 2.1 from

learner’s book page 24 in their groups

• Goes round to check the progress of the

discussion, and intervenes where necessary.

• Guides learners with special educational

needs on how to do activity.

Step 2:

Request a reporter from each group to present

the work on the chalkboard.

In their groups, learners will do activity 2.1.

On a piece of paper, they will draw a tower

with blocks starting with 15 blocks for the

bottom row until they will not be able to add

another row.

• Reporter represents the work.

• Learners interact through questions and

comments.

Answers a)

b) There are 15 rows

c) 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5,

4, 3, 2, 1

d) Observing this sequence the number

that is added to the number to obtain

the next is -1.

• Cooperation and

interpersonal

management developed

through working in

groups.

• Communication:

learners communicate

and convey information

and ideas through

speaking when they are

presenting their work.

• Self confidence:

learners will gain self

confidence competence

when they are

presenting their work.

• In group activities, the

fact of being convinced

without fighting, peace

and education values

are developed too.

Conclusion

10 minutes

Request learners to give the main points of the

learned lesson in summary.

Summarise the learned lesson:

Sequences of numbers that follow a pattern

of adding a fixed number, called common

difference d, from one term to the next are

called arithmetic sequences or arithmetic

progressions. That is d u un n= −+1 or

d u un n= − −1 . For an arithmetic sequence

1 1, ,n n nu u u− + , we have 2 1 1u u un n n= +− + .

• Learners develop

critical thinking through

generating a summary.

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Subsidiary Mathematics Teacher’s Guide Book Five

xxiv

Timing for each step Teacher’s activities Learners’ activities Competences and cross

cutting issues to be

addressed

15 minutes

15 minutes

10 minutes

• Request learners to do questions 1 and 2 of

exercise 2.1 in their respective groups

• Goes round to check the progress of the

discussion, and intervenes where necessary

• Request some learners to answer to questions

1 and 2 of exercises 2.1 on chalkboard.

• Ensures that the learners understood the

learned lesson and decide to repeat the lesson

or to continue with new lesson next time

Give to the learners an individual evaluation

(quiz) and homework to the learned lesson.

Lead into next lesson

Request learners to do activity 2.2 at home.

Do questions 1 and 2 of exercise 2.1, from

learner’s book page 26, in their respective

groups.

Do questions 1 and 2 of exercise 2.1, from

learner’s book page 26, on chalkboard.

Do question 3 of exercise 2.1, from learner’s

book page 26, as individual quiz.

• Through group activities,

cooperation is developed.

• Through presentation

on chalkboard,

communication skills

are developped

Teacher self

evaluation

Even if the objective has been achieved, some

learners had not the instruments of geometry.

The time management has been disturbed by the

fact of borrowing materials from their classmates.

For this reason, next time each learner must have

his/her own materials (instrument of geometry,

calculator, …)

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xxv

Timing for each step Teacher’s activities Learners’ activities Competences and cross

cutting issues to be

addressed

15 minutes

15 minutes

10 minutes

• Request learners to do questions 1 and 2 of

exercise 2.1 in their respective groups

• Goes round to check the progress of the

discussion, and intervenes where necessary

• Request some learners to answer to questions

1 and 2 of exercises 2.1 on chalkboard.

• Ensures that the learners understood the

learned lesson and decide to repeat the lesson

or to continue with new lesson next time

Give to the learners an individual evaluation

(quiz) and homework to the learned lesson.

Lead into next lesson

Request learners to do activity 2.2 at home.

Do questions 1 and 2 of exercise 2.1, from

learner’s book page 26, in their respective

groups.

Do questions 1 and 2 of exercise 2.1, from

learner’s book page 26, on chalkboard.

Do question 3 of exercise 2.1, from learner’s

book page 26, as individual quiz.

• Through group activities,

cooperation is developed.

• Through presentation

on chalkboard,

communication skills

are developped

Teacher self

evaluation

Even if the objective has been achieved, some

learners had not the instruments of geometry.

The time management has been disturbed by the

fact of borrowing materials from their classmates.

For this reason, next time each learner must have

his/her own materials (instrument of geometry,

calculator, …)

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xxvi

Section 7: General Methodology

Follow the following three steps when teaching any lesson.

IntroductionReviews previous lesson, through asking the learners some questions. If there is no previous lesson ask them pre-knowledge questions on the day lesson.

Body of the lessonGive an activity to learners that will be done in groups or individually. Invite one or more groups for presentation of their work to other groups. If the activity is individual, ask one or more learners to present his/her work to others. After activities, capture the main points from the presentation of the learners and summarise them.

ConclusionAsk learners what they learned in day lesson. Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give homework to the learners. Give them two home works: one for the lesson of the day and another which will be activity for the next lesson.

Section 8: Units descriptionUnit 1. Trigonometric Formulae and Equations

Unit 2. Sequences

Unit 3. Logarithmic and Exponential Equation

Unit 4. Trigonometric Functions and their Inverses

Unit 5. Matrices and Determinant of Order

Unit 6. Vector space of Real Numbers

Unit 7. Bivariate Statistics

Unit 8. Conditional Probability and Bayes Theorem

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1

Unit 1 Trigonometric Formulae and Equations

Learner’s Book pages 1–22

Aim

Solve trigonometric equations and related problems using

trigonometric functions and equations

Objectives

After completing this unit, the learners should be able to:

࿌ use trigonometric formulae

࿌ solve trigonometric equations

Materials Exercise books, pens, instrument of geometry, calculators

Contents1.1. Trigonometric formulae

Recommended teaching periods: 9 periodsThis section looks at trigonometric formulae

࿌ Addition and subtraction formulae (compound formulae)

( )( )( )( )

cos cos cos sin sin

cos cos cos sin sin

sin sin cos cos sin

sin sin cos cos sin

x y x y x y

x y x y x y

x y x y x y

x y x y x y

+ = −

− = +

+ = +

− = −

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2

Subsidiary Mathematics Teacher’s Book Five

( )

( )

( )

( )

tan tantan1 tan tantan tantan

1 tan tancot cot 1cotcot cotcot cot 1cotcot cot

x yx yx y

x yx yx y

x yx yy x

x yx yy x

++ =

−−

− =+

−+ =

++

− =−

࿌ Double angles2 2cos 1 sinx x= − and 2 2sin 1 cosx x= −

2 2

sin 2 2sin coscos 2 cos sin

x x xx x x

=

= −

2

2

2 tantan 21 tancot 1cot 2

2cot

xxx

xxx

=−

−=

࿌ Half angle formulae

1 cossin2 2

cos 1cos2 2

x x

x x

−= ±

+= ±

1 costan2 sinx x

x−

= or sintan

2 1 cosx x

x=

+

࿌ Transformation of product in sum

( ) ( )1cos cos cos cos2

x y x y x y= + + −

( ) ( )1sin sin cos cos2

x y x y x y= − + − −

( ) ( )1sin cos sin sin2

x y x y x y= + + −

( ) ( )1cos sin sin sin2

x y x y x y= + − −

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3

Trigonometric Formulae and Equations

࿌ Transformation of sum in product formulae

cos cos 2cos cos2 2

cos cos 2sin sin2 2

sin sin 2sin cos2 2

sin sin 2cos sin2 2

p q p qp q

p q p qp q

p q p qp q

p q p qp q

+ −+ =

+ −− = −

+ −+ =

+ −− =

࿌ t- Formulae

If tan2

=At , then

2

2 2 2

2 1 2sinA ,cos , tan1 1 1

t t tA At t t

−= = =

+ + −

Teaching guidelines

Let learners know basic relations in trigonometry like 1 1 sin 1 cossec , csc , tan , cot

sin cos tan sinx xx x x x

x x x x x= = = = = .

Help them to recall those basic relations. ࿌ Organise class into groups. Request each group to have

a group leader who will present their findings to the class.

࿌ Request each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

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4

Subsidiary Mathematics Teacher’s Book Five

Answers to activities and exercises

Activity 1.1 Page 2

Materials Exercise books, pens

Answers

a) ( )sin + =PRA BOP

+=

PQ QROP+

=PQ TS

OP

cos sin sin cos

PQ TSOP OP

PQ PT TS OTPT OP OT OP

A B A B

= +

= × + ×

= +

So, ( )sin sin cos cos sin+ = +A B A B A B .

b) Similarly, ( )cos + =ORA BOP

cos cos cos cos

OS RSOP

OS QTOP

OS QTOP OP

OS OT QT PTOT OP PT OP

A B A B

−=

−=

= −

= × − ×

= −

Thus, ( )cos cos cos sin sin+ = −A B A B A B .

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5

Trigonometric Formulae and Equations

• ( ) ( )( )

sintan

cos+

+ =+

A BA B

A B

From the identities for ( )sin +A B and ( )cos +A B ,

you have ( ) sin cos cos sintancos cos sin sin

++ =

−A B A BA BA B A B

sin sincos cos

sin sin1cos cos

+=

A BA B

A BA B

sin cos

=

A Bcos cosA B

cos+

A sincos

BA cos

cosB

A cos Bcos A cos B

sin sincos cos

−A BA B

tan tan1 tan tan

+=

−A B

A B

So, ( ) tan tantan1 tan tan

++ =

−A BA B

A B.

• Replacing B by −B in the identity for ( )sin +A B

gives

( ) ( ) ( )sin sin cos cos sin− = − + −A B A B A B

Or ( )sin sin cos cos sin− = −A B A B A B

• Replacing B by −B in the identity for ( )cos +A B

gives

( ) ( ) ( )cos cos cos sin sin+ = − − −A B A B A B .

Thus,

( )cos cos cos sin sin− = +A B A B A B

• Replacing B by −B in the identity for ( )tan +A B

yields

( ) ( )( )

tan tantan

1 tan tan+ −

− =− −

A BA B

A B

Hence, ( ) tan tantan1 tan tan

−− =

+A BA B

A B.

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6

Subsidiary Mathematics Teacher’s Book Five

Exercise 1.1 Page 4

1. a) 6 24+ b) 2 3+

c) ( )2 3− + d) ( )6 2− +

2. 12

3. a) 6 24− b) 6 2

4+

c) 2 3− d) 2 3+

4. a) 5633

b) 6316

Activity 1.2 Page 5

Materials Exercise books, pens

Answers

1. ( )cos cos cos sin sin+ = −x x x x x x2 2cos 2 cos sin⇒ = −x x x

2. ( )cos cos cos sin sin− = +x x x x x x2 2cos 0 cos sin⇔ = +x x

2 21 cos sin⇔ = +x x2 2cos sin 1⇒ + =x x

3. ( )sin sin cos cos sin+ = +x x x x x x

sin 2 2sin cos⇒ =x x x

4. ( ) tan tantan1 tan tan

x xx xx x

++ =

2

2 tantan 21 tan

⇒ =−

xxx

5. ( ) cot cot 1cotcot cot

x xx xx x

−+ =

+2cot 1cot 2

2cot−

⇒ =xx

x

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7

Trigonometric Formulae and Equations

Exercise 1.2 Page 6

1. 3 34sin cos 4cos sinx x x x−

2. 8 8 2 6 4 4 6 2cos sin 28cos sin 70cos sin 28cos sinx x x x x x x x+ − + −

3. a) 12

b) 22

c) 24

d) 32

Activity 1.3 Page 7

Materials Exercise books, pens

Answers

From the double angle formulae, you have

1. 2 2cos 2 cos sin= −x x x

( )2 21 sin sin= − −x x from 2 2cos sin 1+ =x x

21 2sin= − x

So, 2cos 2 1 2sin= −x x

Letting 2xθ = , 2cos 2 1 2sin= −x x gives

2cos 1 2sin2θθ = −

Or 2 1 cos2sin 1 cos sin2 2 2θ θ θθ −

= − ⇒ = ±

So, 1 cossin

2 2θ θ−

= ±

2. 2 2cos 2 cos sin= −x x x

( )2 2cos 1 cos= − −x x from 2 2cos sin 1+ =x x22cos 1= −x

So, 2cos 2 2cos 1= −x x

Letting 2xθ = , 2cos 2 2cos 1= −x x gives

2 2cos 2cos 1 2cos 1 cos2 2θ θθ θ= − ⇔ = +

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8

Subsidiary Mathematics Teacher’s Book Five

( )2 1 1 coscos 1 cos cos2 2 2 2θ θ θθ +

= + ⇒ = ±

Thus, 1 coscos

2 2θ θ+

= ±

3. sin

2tan2 cos

2

θθ

θ=

1 cos2tan

2 1 cos2

θθ

θ

−±

⇔ =+

±

1 costan2 1 cosθ θ

θ−

⇔ =+

By rationalizing denominator, you get

1 cos 1 costan2 1 cos 1 cosθ θ θ

θ θ− −

=+ −

( )2

2

1 costan

2 1 cos

θθθ

−⇔ =

− 2

1 costan

2 1 cos

θθθ

−⇔ =

( )2

1 costan

2 1 cos

θθθ

± −⇔ =

( )1 costan

2 sinθθ

θ± −

⇔ =

1 costan2 sinθ θ

θ−

⇔ =

So, 1 costan

2 sinθ θ

θ−

=

From 1 costan

2 1 cosθ θ

θ−

=+

, conjugating numerator,

you get

1 cos 1 costan2 1 cos 1 cosθ θ θ

θ θ− +

=+ + ( )

2

2

1 costan2 1 cos

θ θ

θ

−⇔ =

+

( )

2

2

sintan2 1 cos

θ θ

θ⇔ =

+

sintan

2 1 cosθθ

θ⇔ =

+

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9

Trigonometric Formulae and Equations

sintan2 1 cosθ θ

θ⇔ =

+

So sintan

2 1 cosθ θ

θ=

+

In fact, 1 costan

2 sinθ θ

θ−

= or sintan

2 1 cosθ θ

θ=

+

Exercise 1.3 Page 9

1. 6 3,

3 3± ±

2. If 7tan 2 , 024 4

A A π= < < , to find tan A

( )( )

2

2

2

2

2 tantan 21

7 2 tan24 17 7 48 tan7 48 tan 7 07 tan 1 tan 7 0

=−

⇒ =−

⇒ − =

⇒ − − =

⇒ − + =

AAtan A

Atan A

tan A Atan A A

A A1tan7

⇒ =A since tanA 7= is impossible for

04π

< <A

3. 7 3 7, ,

4 4 3± ± ±

Activity 1.4 Page 9

Materials Exercise books, pens

Answers

1. ( ) ( )sin sin sin cos cos sinx y x y x y x y+ + − = + sin cos cos sinx y x y+ −

2sin cosx y=

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10

Subsidiary Mathematics Teacher’s Book Five

2. ( ) ( )sin sin sin cosx y x y x y+ − − = ( )cos sin sin cos cos sinx y x y x y+ − −

sin cosx y= cos sin sin cosx y x y+ − cos sin

2cos sin

x yx y

+

=

3. ( ) ( )cos cos cos cos sin sinx y x y x y x y+ + − = − cos cos sin sinx y x y+ +

2cos cosx y

4. ( ) ( ) ( )cos cos cos cos sin sin cos cos sin sinx y x y x y x y x y x y+ − − = − − +

cos cosx y= sin sin cos cosx y x y− − sin sin

2sin sin

x yx y

= −

Exercise 1.4 Page 10

1. ( )1sin cos3 sin 4 sin 22

= −x x x x

2. ( )1cos12 sin 9 sin 21 sin 32

= −x x x x

3. 5 32cos cos cos 4 cos2 2x x x x= +

Activity 1.5 Page 11

Materials Exercise books, pens

Answers

The formulae for transforming product in sum are

( ) ( )1cos cos cos cos2

x y x y x y= + + − (Equation 1)

( ) ( )1sin sin cos cos2

x y x y x y= − + − − (Equation 2)

( ) ( )1sin cos sin sin2

x y x y x y= + + − (Equation 3)

( ) ( )1cos sin sin sin2

x y x y x y= + − − (Equation 4)

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11

Trigonometric Formulae and Equations

2

2

p qxx y px y q p qy

+ =+ = ⇒ − = − =

(i)

From equation (equation 1) and (i), you get

( )1cos cos cos cos2 2 2

p q p q p q+ −= +

From equation (equation 2) and (i), you get

( )1sin sin cos cos2 2 2

p q p q p q+ −= − −

From equation (equation 3) and (i), you get

( )1sin cos sin sin2 2 2

p q p q p q+ −= +

From equation (equation 4) and (i), you get

( )1cos sin sin sin2 2 2

p q p q p q+ −= −

Exercise 1.5 Page 12

1. cos cos 7 2cos 4 cos3x x x x+ =

2. 13 5sin 4 sin 9 2cos sin

2 2x xx x− = −

3. 7sin 3 sin 4 2sin cos2 2x xx x+ =

1.2. Trigonometric equations

Recommended teaching periods: 6 periodsThis section looks at the method used to solve trigonometric

equations.

The solutions of a trigonometric equation for which 0 2π≤ ≤x

are called principle solutions while the expression (involving

integer k) of solution containing all values of the unknown angle

is called the general solution of the trigonometric equation.

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12

Subsidiary Mathematics Teacher’s Book Five

When the interval of solution is not given, you are required to

find general solution.

When solving trigonometric equation, note that

࿌ general solution for

1. sin 0=x is ,π= ∈x k k

2. cos 0=x is ( )2 1 ,2π

= + ∈x k k

3. tan 0=x is ,π= ∈x k k

4. all angles having the same sine i.e. sin sinθ=x is

( )1 ,θ π= − + ∈kx k k

5. all angles having the same cosine i.e. cos cosθ=x

is 2 ,θ π= ± + ∈x k k

6. all angles having the same tangent i.e. tan tanθ=x

is ,θ π= + ∈x k k ࿌ The sum or difference of trigonometric functions containing

unknown are transformed into the sum.

Remember that

cos cos 2cos cos2 2

cos cos 2sin sin2 2

sin sin 2sin cos2 2

sin sin 2cos sin2 2

p q p qp q

p q p qp q

p q p qp q

p q p qp q

+ −+ =

+ −− = −

+ −+ =

+ −− =

࿌ To find the general solution of the equation of the form sin cos+ =a x b x c where , , c∈a b such that 2 2≤ +c a b

Using t-formula 2

2 2

2 1sin ,cos1 1

−= =

+ +t tx xt t

, where

tan2

=xt , gives

( )2

2 22 2

2 1 2 11 1

−+ = ⇒ + − = +

+ +t ta b c at b bt c tt t

( ) 2 2 0⇔ + − + − =b c t at c b

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13

Trigonometric Formulae and Equations

which is quadratic equation in t .

Remember that tan2

=xt .

Alternative method: in sin cos+ =a x b x c

a) Divide each term by 2 2+a b and convert it in the form

2 2 2 2 2 2sin cos+ =

+ + +

a b cx xa b a b a b

b) Let tanθ =ba

, then 2 2 2 2

sin ,cosθ θ= =+ +

b aa b a b

.

c) The given equation reduces to the form

cos cos sin sinθ θ+ =r x r x c

or cos cos sin sinθ θ+ =cx xr

d) Then, ( )cos cosθ α− =x , where 2 2

cosα = =+

c cr a b

Therefore 2 ,α θ π= ± + + ∈x k k

Notice:In solving the trigonometric equation, it is helpful to remember

the following identities:

( )( )( )

sin sin 2 ,

cos cos 2 ,

tan tan ,

k k

k k

k k

α α π

α α π

α α π

= + ∈

= + ∈

= + ∈

( )( )( )

sin sin

cos cos

tan tan

α π α

α α

α α π

= −

= −

= +

Teaching guidelines

Let learners know what inverse function is. Help them to

recall that ( )1f f x x− = . Make sure that learners have

scientific calculators.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

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14

Subsidiary Mathematics Teacher’s Book Five

࿌ Request each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 1.6 Page 12

Materials Exercise books, pens and calculator

Answers

1. 2

6 ,5 26

kk

k

π π

π π

+ ∈ +

2. 2 ,4

k kπ π± + ∈

Exercise 1.6 Page 14

1. ,12 4π π

± + ∈k k

2. 0,14 3π π

3. 5 13 17 25 29, , , , ,

18 18 18 18 18 18π π π π π π

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15

Trigonometric Formulae and Equations

4. ( )0 0 0 030 ,150 ,199.5 ,340.5

5. 5,

6 6π π

6. ( )12 3

k kπ π+ ∈

7. a) ( )2 1 ,4π π+ ∈k or k k

b) ∈or k k

c) ( )2 1 ,3 2π π

+ ∈k or k k

d) ( ) ( )2 1 2 1 ,4 2π π

+ + ∈k or k k

Activity 1.7 Page 14

Materials Exercise books, pens and calculator

Answers

1. 3 cos sin 3− =x x

We know that 2

2

1cos1

−=

+txt

and 2

2sin1

=+

txt

where tan2

=xt

2

2 2

1 23 cos sin 3 3 31 1

−− = ⇔ − =

+ +t tx xt t

( ) ( )2 23 1 2 3 1⇔ − − = +t t t2 23 3 2 3 3⇔ − − = +t t t

2 23 2 3⇔ − =t t t22 3 2 0⇔ − − =t t

23 0⇔ + =t t

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16

Subsidiary Mathematics Teacher’s Book Five

2. Solution of 23 0+ =t t

23 0+ =t t ( )3 1 0⇔ + =t t 0 3 1 0⇒ = + =t or t

103

⇔ = = −t or t

3. From t, let us find the value of x

0 tan 02

= ⇔ =xt

,2

π⇒ = ∈x k k

So, 2 ,π= ∈x k k

1 1tan23 3

= − ⇔ = −xt

2 6π π⇒ = − +

x k

Thus, 2 ,3π π= − + ∈x k k

Exercise 1.7 Page 16

1. , ,6 2π ππ = + = ∈

x k x k 2. ,

4π π = + ∈

x k k

3. 2 , 2 ,6 2π ππ π+ + ∈k k k 4. 0 0119.7 ,346.8

1.3. Applications

Activity 1.8 Page 16

Materials Exercises book, pens

AnswersBy reading text books or accessing internet, learners will discuss on harmonic motion and how trigonometry is used in harmonic motion.

An object that moves on a coordinate axis is in simple harmonic motion if its distance from the origin, d, at time t is given by either cosd a tω= or sind a tω= .

The motion has amplitude a , the maximum displacement of the object from its rest position. The period of the motion is 2π

ω, where 0ω > .

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17

Trigonometric Formulae and Equations

Activity 1.9 Page 17

Materials Exercises book, pens

AnswersBy reading text books or accessing internet, learners

will discuss on Snell’s law.

The degree of bending of the light’s path depends on

the angle that the incident beam of light makes with

the surface, and on the ratio between the refractive

indices of the two media.

n2

n1

θ1

θ2

0

Q

v1interface

norm

al

v2

Snell’s law state that: 1 1 2 2sin sinn nθ θ=

End of Unit Assessment Page 22

1. 3

2 4

4 tan 4 tan1 6 tan tan

x xx x

−− +

2. 4 2

3

cot 6cot 14cot 4 tan

x xx x

− +−

3. 1−

4. ( ) tan tantan1 tan tan

A BA BA B+

+ =−

11 2 1

111 2 1

aa a

aa a

++ +=

− ×+ +

( )( )( )( )

( )( )2 1 2 12 1

1 2 1 1 2 1a aa a a

a a a a a+ ++ + +

= ×+ + + + −

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18

Subsidiary Mathematics Teacher’s Book Five

2

2

2 2 12 2 11

a aa a a a

+ +=

+ + + −=

( )tan 1 ,4

A B A B k kπ π+ = ⇒ + = + ∈

For 0,4

k A B π= + =

5. a) 12

b) 22

c) 1− d) 3

2

6. 725

7. 120119

8. a) 172cos cos2 2

x b) 2sin 7 cos 4x x

9. a) ( )1 sin15 sin 72

−x x b) ( )1 sin16 sin 22

+x x

10. a) 2 ,3π π± + ∈k k b) 2 ,

3π π± + ∈k k

c) 5 2 ,6π π+ ∈k k d) ,

6 3π ππ π+ − + ∈k or k k

11. a) ( ) ( )2 1 , 2 1 ,2 8π π

+ + ∈k k k

b) ( )2 , 2 1 ,5 11π π

+ ∈k k k

c) , k ,4 3π π π± + ∈

k k

d) ( )2 1 , ,2π π+ ∈k k k

12. a) 2 ,2π π+ ∈k k b) 2 ,

6 3π π π− ± + ∈k k

c) 2 ,6 3π π π± + ∈k k d) 2 ,

4π π+ ∈k k

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19

Unit 2 Sequences

Learner’s Book pages 23–56

Aim

Understand, manipulate and use arithmetic, geometric

sequences.

Objectives

After completing this unit, the learners should be able to:

࿌ Define a sequence

࿌ Identify arithmetic and geometric progressions and their properties

࿌ Use sequences in daily life

Materials Exercise books, pens, instruments of geometry, calculator

Contents2.1. Arithmetic sequences and harmonic sequences

Recommended teaching periods: 5 periodsThis section studies the arithmetic sequences and the harmonic

sequence.

Arithmetic progression

A finite or infinite sequence 1 2 3, , , , na a a a or 1 2 3, , , , , na a a a

is said to be an Arithmetic Progression (A.P.) or Arithmetic

Sequence if 1−− =k ka a d , where d is a constant independent

of k , for 2,3, ,= k n or 2,3, , ,= k n as the case may be.

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20

Subsidiary Mathematics Teacher’s Book Five

Characteristics If three consecutive terms, 1 1, ,− +n n nu u u are terms in arithmetic

sequence, then, 1 12 − += +n n nu u u

Common difference In A.P., the difference between any two consecutive terms is a

constant d , called common difference

General term or nth term

The nth term, nu , of an arithmetic sequence { }nu with common

difference d and initial term 1u is given by ( )1 1nu u n d= + −

Generally, if pu is any thp term of a sequence, then the nth term

is given by ( )n pu u n p d= + −

Arithmetic meansIf three or more than three numbers are in arithmetic sequence,

then all terms lying between the first and the last numbers are

called arithmetic means. If B is arithmetic mean between A

and C , then 2+

=A CB .

To insert k arithmetic means between two terms 1u and nu is

to form an arithmetic sequence of 2n k= + terms whose first

term is 1u and the last term is nu .

Sum of first nth terms or arithmetic seriesThe sum of first n terms of a finite arithmetic sequence with

initial term 1u is given by ( )12= +n n

nS u u which is called finite

arithmetic series

Harmonic sequenceA sequence is said to be in harmonic progression if the

reciprocals of its terms form an arithmetic progression.

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21

Sequences

Characteristics If three consecutive terms, 1 1, ,− +n n nh h h are terms in arithmetic

sequence, then, 1 1

1 1

2 − +

− +

+= n n

n n n

h hh h h

or

1 1 1 1

1 1 1 1

22

− + − +

− + − +

= ⇔ =+ +

n n n n nn

n n n n

h h h h hhh h h h

General term or nth term of H.P.Take the reciprocals of the terms of the given series; these

reciprocals will be in A.P.

Find nth term of this A.P. using ( )1 1nu u n d= + − or

( )n pu u n p d= + −

Take the reciprocal of the nth term of A.P., to get the required

nth term of H.P.

Thus, the nth term of H.P. is ( )1

11+ −u n d

or ( )1

+ −pu n p dHarmonic meansIf three or more than three numbers are in harmonic sequence,

then all terms lying between the first and the last numbers are

called harmonic means. If B is harmonic mean between A and

C, then 2+

=A CB .

To insert k harmonic means between two terms 1h and nh is to

form a harmonic sequence of 2n k= + terms whose first term

is 1h and the last term is nh .

Teaching guidelines

࿌ Organise the class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

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22

Subsidiary Mathematics Teacher’s Book Five

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 2.1 Page 24

Materials Exercise books, pens, instruments of geometry

Answersa)

b) There are 15 rows

c) 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1

d) That number is -1

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23

Sequences

Exercise 2. 1 Page 26

1. a) { } 105,11,17,23 , 59u = b) { } 1043,38,33,28 , 2u = −

c) { } 107, 3,1,5 , 29u− − = d) { } 101, 8, 15, 22 , 64u− − − − = −

2. No. The number added to the 4th term to obtain the

5th term is not equal to the one used for previous first

terms.

3. Common difference is 2

4. 3 7x or= , fourth term: 0 or 60

Activity 2.2 Page 27

Materials Exercise books, pens

Answers

( )2 1

3 2 1 1

u u du u d u d d u d

= +

= + = + + = +

( )4 3 1 12 3u u d u d d u d= + = + + = +

( )5 4 1 13 4u u d u d d u d= + = + + = +

( )6 5 1 14 5u u d u d d u d= + = + + = +

( )7 6 1 15 6u u d u d d u d= + = + + = +

( )8 7 1 16 7u u d u d d u d= + = + + = +

( )9 8 1 17 8u u d u d d u d= + = + + = +

( )10 9 1 18 9u u d u d d u d= + = + + = +

Generally,

( ) ( )1 1 1( 2) 1n nu u d u n d d u n d−= + = + − + = + −

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24

Subsidiary Mathematics Teacher’s Book Five

Exercise 2. 2 Page 291. 3 2. 9 3. 15

4. Answer is iii) 508th

5. 19, 36

Activity 2.3 Page 30

Materials Exercise books, pens, calculators

Answers

1 72, 20= =u u

( )1 7 11 6= + − ⇒ = +nu u n d u u d

20 2 6⇒ = + d

3⇒ =d

The sequence is 2,5,8,11,14,17,20

Exercise 2. 3 Page 31

1. 3, 1,1,3,5,7− −

2. 2,5,8,11,14,17,20,23,26,29,32

3. 1 1 1 1 16 , 9 , 12 , 15 , , 392 2 2 2 2

− − − − −

4. 8 and 4

Activity 2.4 Page 31

Materials Exercise books, piece of paper (or manila paper), pens

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25

Sequences

Answers

( )( )

1 1

2 1

1 1

1

2

1n

n

u uu u d

u u n d

u u n d−

== +

= + −

= + −

Let ns denote the sum of these terms.

We have

[ ] ( ) ( )1 1 1 1... 2 1ns u u d u n d u n d= + + + + + − + + −

Reversing the order of the sum, we obtain

( ) ( ) [ ]1 1 1 11 2 ...ns u n d u n d u d u= + − + + − + + + +

Adding the left sides of these two equations and

corresponding elements of the right sides,

we see that:

( ) ( ) ( )( )

1 1 1

1

2 2 1 2 1 ... 2 1

2 1ns u n d u n d u n d

n u n d

= + − + + − + + + − = + −

( ) ( )1 1 12 1 12 2nn ns u n d u u n d⇔ = + − = + + −

By replacing ( )1 1u n d+ − with nu , we obtain a useful

formula for the sum:

[ ]12n nns u u= +

or ( )( ) ( )( )1 1 11 2 12 2

= + − ⇒ = + −n nn ns u u n d s u n d

Exercise 2. 4 Page 33

1. ( )2 3n n + 2. 860 3. 11

4. 144 5. 45045

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26

Subsidiary Mathematics Teacher’s Book Five

Activity 2.5 Page 33

Materials Exercise books, piece of paper (or manila paper), pens

Answers1 1 1 1 1 1 1 1, , , , , , ,2 4 6 8 10 12 14 16

The denominators are in arithmetic progression.

Exercise 2. 5 Page 36

1. The sequence is 12 12 3 46,4,3, , 2, , ,5 7 2 3

.

1245

th term is , 483

th term is

2. 90 903, , ,1023 16

3. The nth term is 6n

4. The nth term is 205 3+n

5. 22nd term

2.2. Geometric sequences

Recommended teaching periods: 7 periodsThis section studies the geometric sequences

Definition A Geometric Progression (G.P.) or Geometric Sequence is a

sequence in which each term is a fixed multiple of the previous

term i.e. 1−

=k

k

a ra

, where r is a constant independent of k , for

2,3, ,= k n or 2,3, , ,= k n .

Characteristics If three consecutive terms, 1 1, ,− +n n nu u u are terms in geometric

progression, then, 21 1− +=n n nu u u

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27

Sequences

Common ratioIn G.P., the ratio between any two consecutive terms is a

constant r, called common ratio

General term or nth term

The nth term, nu , of a geometric sequence { }nu with common

ratio r and initial term 1u is given by 11

−= nnu u r

Generally, if pu is any thp term of a sequence then the nth term

is given by −= n pn pu u r

Geometric means If three or more than three numbers are in geometric sequence, then all terms lying between the first and the last numbers are called geometric means.

To insert k geometric means between two terms 1u and nu is to form a geometric sequence of 2n k= + terms whose the first

term is 1u and the last term is nu .

Sum of first nth terms or geometric seriesThe sum of first n terms of a finite geometric sequence with initial

term 1u is given by ( )1 1

, 11

−= <

n

n

u rS r

r or

( )1 1, 1

1−

= >−

n

n

u rS r

rwhich is called finite geometric series

If the initial term is 0u , then the formula is ( )1

0 11

n

n

u rs

r

+−=

with 1r ≠

If 1r = , 1ns nu=

Also, the product of first n terms of a geometric sequence with

initial term 1u and common ratio r is given by ( )( )1

21

n nn

nP u r−

=

If the initial term is 0u then ( ) ( )11 20

n nnnP u r

++=

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28

Subsidiary Mathematics Teacher’s Book Five

Teaching guidelines

Let learners know what arithmetic sequence is. Recall that for an arithmetic sequence we add a constant number to the term to obtain the next term.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 2.6 Page 37

Materials Exercise books, piece of paper (or manila paper), pens,

calculator, scissors or blades

AnswersLearners will take a piece of paper and cut it into two equal part. Take one part and cut it again into two equal parts. When they continue in this way the fraction corresponding to the obtained parts according to the original piece of paper are as follows:

1 1 1 1 1, , , , ,...2 4 8 16 32

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29

Sequences

Exercise 2.6 Page 39

1. 6 6x or= −2. No, the number multiplied to the fourth term

to obtain fifth term is not the same as the one used for previous terms.

3. Common ratio is -2.

Activity 2.7 Page 39

Materials Exercise books, pens, calculators

AnswersGeneration ( )n Number of ancestors Observation

1st 2 02 1 2 2× = ×2nd 4 12 2×3rd 8 22 2×4th 16 32 2×5th 32 42 2×6th 64 52 2×7th 128 62 2×8th 256 72 2×9th 512 82 2×

10th 1024 92 2×11th 2048 102 2×12th 4096 112 2×

n 12 2 −× n

1. Up to 6th generation , this person has 564 2 2= × ancestors

2. Up to 8th generation, this person has 7256 2 2= × ancestors

3. Up to 10th generation, this person has 91024 2 2= × ancestors

4. Up to 12th generation, this person has 114096 2 2= × ancestors

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30

Subsidiary Mathematics Teacher’s Book Five

We have 2,4,8, 12th term which are in geometric

progression.

Here, 1 2, 2= =a r

The general formula which can be used is 12 2 2−× =n n

Exercise 2. 7 Page 42

1. 4 16=u 2. 98304

3. 5 164

4. 10

6

23

5. i) 12 1380=u ii) 28 1190=u

Activity 2.8 Page 42

Materials Exercise books, pens, calculators

Answers

1 61, 243= =u u

1 51 6 1

−= ⋅ ⇒ = ⋅nnu u r u u r

5243⇒ = r 5 53⇒ = r 3⇒ =r

The sequence is 1,3,9,27,81,243

Exercise 2. 8 Page 44

1. 1 1 1 1 1 1 1, , , , , ,4 8 16 32 64 128 256

or 1 1 1 1 1 1 1, , , , , ,4 8 16 32 64 128 256

− − −

2. 2 2 2 2 2 22, , , , , ,3 9 27 81 243 729

or 2 2 2 2 2 22, , , , , ,3 9 27 81 243 729

− − −

3. 92

4. a) 162

b) 6

5. 1 ,1,33

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31

Sequences

Activity 2.9 Page 44

Materials Exercise books, pens

Answers

1. Let 1 2 3 ...n ns u u u u= + + + +2 1

1 1 1 1... nns u u r u r u r −= + + + + (1)

Multiply both sides of (1) by r, we obtain2 3

1 1 1 1... nns r u r u r u r u r= + + + + (2)

Subtract (2) from (1), we get2 1

1 1 1 1

2 31 1 1 1

1 1

...

...

nn

nn

nn n

s u u r u r u r

s r u r u r u r u r

s s r u u r

− = + + + +

− = − − − − −

− = −

( ) ( )11 1 nns r u r⇔ − = − or

( )1 11

n

n

u rs

r−

=−

with 1r ≠

2. 2 11 1 1 1... nP u u r u r u r −= × × × ×

( ) ( )2 11 ...n nP u r r r −⇔ = × × ×

( ) ( )1 2 ... 11

n nP u r + + + −⇔ =

We need the sum 1 1 2 ... 1nS n− = + + + −

( ) ( )1

11 1 12 2n

n nnS n−

−−= + − =

Then ( )( )1

21

n nn

nP u r−

=

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32

Subsidiary Mathematics Teacher’s Book Five

Exercise 2. 9 Page 471) 21.25 2) 39.1

3) First term is 1, common ratio is 54

4) -32 5) 8th

Activity 2.10 Page 47

Materials Exercise books, pen

Answers

If 1 1r− < < , lim 0→∞

=n

nr

thus ( )1 11

lim1 1→∞

−=

− −

n

n

u r ur r

Exercise 2. 10 Page 48

1. a) 403

< <x b) 19039

2. 115m

2.3. Applications

Activity 2.11 Page 49

Materials Exercises book, pens

AnswersBy reading text books or accessing internet, learners

will discuss on how sequences are used in real life.

For example; the interest portion of monthly payments

made to pay off an automobile or home loan, and the

list of maximum daily temperatures in one area for a

month are sequences. One application in economy

is calculation of interset rate. The compound interest

formula: 1ktrA P

k = +

with P = principle, t = time

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33

Sequences

in years, r = annual rate, and k = number of periods

per year. The simple interest formula:

PI rt= with I = total interest, P = principle,

r = annual rate, and t = time in years.

End of Unit Assessment Page 54

1. a) 20 2078, 800u S= = b) 20 2023.5, 185u S= =

2. a) ( ) ( )2 1 , 3n nu n S n n= + = +

b) ( )20 3 , 37 32n nnu n S n= − = −

c) 1 1,

2n nnu S

n+

= =

3. a) 8 818, 88u S= = b) 1 103, 210u S= =

c) 10, 2n d= = d) 1 1, 2u d= =

4. 157 79 159 161 81 163 165 83 167, , , 40, , , , 41, , , , 42,...4 2 4 4 2 4 4 2 4

5. 5,7,9,11,13,15,17,19,21,23,25,27,29,31,...

6. 7 6 5 3 2 1 12, , , , 1, , , ,0,4 4 4 4 4 4 4

− − − − − − − −

7. 8,9,10

8. 9,11,13 or 13,11,9

9. a) 5 5768, 341u S= = b) 1 1533,2 64nr S= =

10. 5812

u = 11. 82187

4u =

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34

Subsidiary Mathematics Teacher’s Book Five

12. 2, 2 2, 4, 4 2,8 or 2, 2 2,4, 4 2,8− −

13. 3,6,12 14. 128 or -972

15. 6, 6, 6 or 6, -3, -12. 16. 11,17,23

17. 5,8,11,14 18. -4,-1,2,5,8

19. 2,3 20. 6

21. £11 million 22. 23

23. 4 ,55

23. 2048000 25. 099.8 F 26. 1800

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35

Unit 3 Logarithmic and Exponential Equations

Learner’s Book pages 57–75

Aim

Solve equations involving logarithms or exponentials and

apply them to model and solve related problems

Objectives

࿌ Solve simple exponential equations.

࿌ Convert a number from logarithmic form to exponential form.

࿌ Change the base of any logarithm.

࿌ Use the properties of logarithms to solve logarithmic and exponential equations.

࿌ Apply logarithms or exponential to solve interest rate problems, population growth problems, radioactivity decay problems, earthquake problems,…

Materials Exercise books, pens, instruments of geometry, calculator

Contents3.1. Exponential and logarithmic functions

Recommended teaching periods: 3 periodsThis section looks at how to sketch exponential and logarithmic

function in Cartesian plane.

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36

Subsidiary Mathematics Teacher’s Book Five

The graph of a logarithmic function is found by reflecting the

graph of the corresponding exponential function to the first

bisector, i.e. the line y x= .

Then the coordinates of the points for = xy a are reversed to

obtain the coordinates of the points for ( ) log= ag x x .

Teaching guidelines

Let learners know how to draw linear function in 2-dimensions.

Recall that to sketch a function you need a table of points.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 3.1 Page 58

Materials Exercise books, pens, instruments of geometry, calculator

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37

Logarithmic and Exponential Equation

Answers

-9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9

-7

-6

-5

-4

-3

-2

-1

1

2

3

4

5

6

7

x

y

0

2xy =y x=

2y =

3y = −

( )g x

Any horizontal line crosses the curve at most once

2xy = is one to one function (is invertible function)

Exercise 3.1 Page 59

-9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10

-6

-5

-4

-3

-2

-1

1

2

3

4

5

6

7

8

x

y

12

x

y =

0

112

logy x− =

y x=

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38

Subsidiary Mathematics Teacher’s Book Five

-9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10

-5

-4

-3

-2

-1

1

2

3

4

5

6

7

8

9

x

y

13

x

y =

0

113

logy x− =

y x=

3.2. Exponential and logarithmic equations

Recommended teaching periods: 6 periodsThis section looks at the method used to solve exponential and

logarithmic equations.

In solving exponential or logarithmic equations, remember

basic rules for exponents and/or logarithms.

Basic rules for exponents For 0 1, ,a and a m n IR> ≠ ∈

a) m n m na a a +× = b) :m n m na a a −=

c) ( )nm mna a= d) 1n

naa

− =

e) 1

nna a= f) m

n mna a=

g) loga ba b=

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39

Logarithmic and Exponential Equation

Basic rules for logarithms

] [ ] [ { }, 0, , 0, \ 1 :x y a∀ ∈ +∞ ∈ +∞

a) log log loga a axy x y= + b) 1log loga a yy

= −

c) log log loga a ax x yy

= − d) log logra ax r x=

e) logloglog

ca

c

bba

=

Teaching guidelines

Let learners know how to solve linear and quadratic equations.

They should also know basic properties of powers. Help them

to recall basic properties of powers.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

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40

Subsidiary Mathematics Teacher’s Book Five

Answers to activities and exercises

Activity 3.2 Page 60

Materials Exercise books, pens, calculators

Answers

If log , log= =a am x n y and log= az xy then

,= =m nx a y a and = zxy a .

Now, += = = ⇒ = +m n m n zxy a a a a z m n .

Thus, ( )log log log= +a a axy x y .

If log , log= =a am x n y and log= axzy

then

,= =m nx a y a and = zx ay

.

Now, −= = = ⇒ = −m

m n zn

x a a a z m ny a

.

Thus, ( )log log log= −a a axy x y .

Exercise 3.2 Page 62

1. a) m n m n

m factors n factors m n factors

a a a a a a a a a a a a a a a +

+

⋅ = ⋅ ⋅ × ⋅ ⋅ = ⋅ ⋅ =

b) 1m

m m nn n

a a aa a

−= =

c) ( )nm mn

m factors m factors m factors

n factors

a a a a a a a a a a a a a a= ⋅ ⋅ × ⋅ ⋅ ⋅ ⋅ =

d) ( )11 1 1 mmm m

m m a aa a a

− − = = = =

e) 1

nna a= from definition

f) ( )1m

nm mn na a a= =

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41

Logarithmic and Exponential Equation

2. a) 4log 64 3= b) 21log 38

= − c) 12

log =y x

d) log 3=p q e) 8log 0.5 = x f) 5log =q p

3. a) 32log 8 8 2 2 2 3= ⇔ = ⇔ = ⇒ =x xx x

b) 3 3log 125 3 125 125 5= ⇔ = ⇒ = ⇔ =x x x x

c) 0.5 2log 64 0.5 64 64 4096= ⇔ = ⇒ = ⇔ =x x x x

d) 34log 64 64 4 4 4 3= ⇔ = ⇔ = ⇒ =x xx x

e)

71 132 2

91log 3 9 9 21872

= ⇔ = ⇔ = ⇒ =

x x x x

f) 12

1 1log 2 2 2 12 2

−= ⇔ = ⇔ = ⇒ = −x xx x

4. a) 5 b) 1.5 c) 3−

d) 3− e) 13

f) 1

g) 1 h) 0

Activity 3.3 Page 62

Materials Exercise books, pens

Answers

1. logax m= and ( )log= paz m then = xm a ,

=p xm a .

Now, ( )= = = ⇒ =pp x px zm a a a z px .

Thus, ( )log logpa am p m= , as required.

2. logloglog

ca

c

bba

=

Let loga b x= , then =xa b .

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42

Subsidiary Mathematics Teacher’s Book Five

Take logarithms in base c of both sides

log log=xc ca b .

This gives loglog loglog

= ⇒ = cc c

c

bx a b xa

.

Therefore, logloglog

ca

c

bba

=

Exercise 3.3 Page 65

1. a) 4 p b) 2− p c) 1+ p

2. a) 2ex

b) 2

2

xy

c) 2 3lnx x− +

3. a) ln 5ln 2

b) ln 23ln 3

c) 1 ln17 16 ln 2

d) { }ln 2, ln 3

3.3. Applications

Activity 3.4 Page 65

Materials Exercise books, pens, calculators

Answers

( ) 0 2= ktP t PHere ( ) 2 1

0 2, 2, 2 += = ⇒ = tP k t in hours P t

a) ( ) 94 2 512= =P

b) ( ) 13 2 1 132 2 2+= ⇔ =tP t 2 1 13 6⇒ + = ⇒ =t t

c) Number of cells left is 22

212 22

or

Activity 3.5 Page 67

Materials Exercise books, pens, calculators

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43

Logarithmic and Exponential Equation

Answersa) The original amount of material present is

( ) ( )00 80 2 80A gram= =

b) For the half life, ( ) 40A t =

10040 80 2t

− =

1001 2

2

t−

⇒ =

1 1002 2t

−−⇒ =

1 100100

t t= ⇒ =

Therefore the half life is 100 years

c) ( ) 1A t =

10080 2 1t

− ⇒ =

100 12

80

t−

⇒ =

11002 80t

− −⇒ =

1100log 2 log80t

− −⇒ = log 2 log80100

t⇒ − = −

log80 100 632log 2

t⇒ = × =

Therefore, it will take 632 years for material to

decay to 1 gram.

Activity 3.6 Page 67

Materials Exercise books, pens

Answers

Suppose ( )P t has an exponential decay model so

that ( ) ( )0 0ktP t P e k−= < .

At any fixed time 1t let

11 0

ktP P e−=

be the value of ( )P t and let T denote the amount

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44

Subsidiary Mathematics Teacher’s Book Five

of time required to reduce in value by half. Thus,

at time 1t T+ the value of ( )P t will be 12P so that ( )1 1

1 0 02 k t T kt kTP P e P e e− + − −= = .

Since 11 0

ktP P e−= , ( ) 11 11 1 1

1 0 0 0 02 2ktk t T P ekt kt ktkT kTP P e P e e P e P e e

−− + =− − −− −= = → =

Or 2 kTe−= , taking ln on both sides gives

ln 2 kT= − or 1 ln 2Tk

= − which does not depend on

0P or 1t .

Exercise 3.4 Page 731. About 1,012

2. 29.15 years

3. 1,250

4. About 99.424; a little over 182 years.

5. 866 years

6. Frw 7,557.84

7. a) 10 years b) (i) 8 years (ii) 32.02 years.

End of Unit Assessment Page 75

1. 5 2. 1.5 3. 1.09

4. 1.5 5. -3 6. 1.05

7. { }81 8. { }1,6− 9. { }6

10. 1 ,55

11. 14

12. { }2

13. a) 38.7 million b) 46.4million c) 48.4million

14. a) 20.8 years b) 138 years

15. 012.9

16. a) 3.33sec b) 4.72sec c) 13.3sec

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45

Unit 4 Trigonometric Functions and their Inverses

Learner’s Book pages 77–122

Aim

Apply theorems of limits and formulae of derivatives to solve

problems including trigonometric functions, optimisation,

and motion.

Objectives

After completing this unit, the learners should be able to:

࿌ find the domain and range of trigonometric function and their inverses.

࿌ study the parity if trigonometric functions.

࿌ study the periodicity of trigonometric functions.

࿌ evaluate limits of trigonometric functions.

࿌ differentiate trigonometric functions.

Materials Exercise books, pens, instruments of geometry, calculator

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46

Subsidiary Mathematics Teacher’s Book Five

Contents4.1. Generalities on trigonometric functions and their inverses

Recommended teaching periods: 6 periodsThis section looks at the domain and range of trigonometric

functions and their inverses. It also looks at the parity and

periodicity of trigonometric functions.

Domain and range of trigonometric functions

Cosine and sine

The domain of sin x and cos x is the set of real numbers.

The range of sin x and cos x is [ ]1,1− .

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47

Trigonometric Functions and their Inverses

Tangent and cotangent

The domain of tan x is \ ,2

k kπ π + ∈

. The range of tan x

is the set of real numbers.

The domain of cot x is { }\ ,k kπ ∈ . The range of cot x is the

set of real numbers.

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48

Subsidiary Mathematics Teacher’s Book Five

Secant and cosecant

The domain of sec x is \ ,2

k kπ π + ∈

. Since 1sec

cosx

x=

and range of cosine is [ ]1,1− , 1

cos x will vary from negative

infinity to -1 or 1 to plus infinity. Thus the range of sec x is

] ] [ [, 1 1,−∞ − ∪ +∞

The domain of csc x is { }\ ,k kπ ∈ . Since 1csc

sinx

x= and

range of sine is [ ]1,1− , sin

will vary from negative infinity to -1

or 1 to plus infinity. Thus, the range of csc x is ] ] [ [, 1 1,−∞ − ∪ +∞

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49

Trigonometric Functions and their Inverses

Inverse trigonometric functionssin x and cos x have the inverses called inverse sine and

inverse cosine denoted by 1sin x− and 1cos x− respectively.

Note that the symbols 1sin x− and cos are never used to

denote 1sin x

and 1cos x

respectively. If desired, 1sin x

and 1

cos x

can be written as ( ) 1sin x − and ( ) 1cos x − (or csc x and sec x )

respectively.

To define 1sin x− and 1cos x− we restrict the domain of

sin x and cos x to the interval ,2 2π π −

and [ ]0,π

respectively to obtain a one-to-one function.

In older literature, 1sin x− and 1cos x− are called arcsine of x and arccosine of x and they are denoted by sinarc x and

cosarc x respectively.

Inverse tangent and inverse cotangentTangent of x, denoted tan x , is a function which is defined for

all positive and negative values of x except 0 090 , 270 ,...± ± . The

range of tan x is ( ),−∞ +∞ . It has the inverse called inverse

tangent and is denoted by 1tan x− .

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50

Subsidiary Mathematics Teacher’s Book Five

To define 1tan x− , we restrict the domain of tan x to ,2 2π π −

.

We will summarize the property of inverse cotangent briefly:1coty x−= is equivalent to tanx y= if 0 y π< < and

x−∞ < < +∞

Inverse secant and inverse cosecantThe inverse secant, denoted 1sec x− , is defined to be the inverse

of restricted secant function.

The domain of 1sec x− is ( ] [ ), 1 1,−∞ − ∪ +∞ and the range is

0, ,2 2π π ∪

We will summarize the property of inverse cosecant briefly:

1cscy x−= is equivalent to cscx y= if 02

yπ− ≤ < or 0

2y π

< ≤

and 1x ≥

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51

Trigonometric Functions and their Inverses

Domain restrictions that make the trigonometric functions

one to oneFunction Domain restriction Range

Sine [-1,1]

Cosine [0,π] [-1,1]

Tangent ,2 2π π −

Cotangent ] [0,π

Secant [ ]0, ,2 2π π π ∪

] ] [ [, 1 1,−∞ − ∪ +∞

Cosecant [ ],0 0,2 2π π − ∪

] ] [ [, 1 1,−∞ − ∪ +∞

Because sin x (restricted) and 1sin x− ; cos x (restricted) and 1cos x− are inverses to each other, it follows that:

࿌ ( )1sin sin y y− = if 2 2

yπ π− ≤ ≤ ; ( )1sin sin x x− = if 1 1x− ≤ ≤

࿌ ( )1cos cos y y− = if 0 y π≤ ≤ ; ( )1cos cos x x− = if 1 1x− ≤ ≤

From these relations, we obtain the following important result:

Theorem 1 ࿌ If 1 1x− ≤ ≤ and

2 2yπ π

− ≤ ≤ , then 1siny x−= and

sin y x= are equivalent.

࿌ If 1 1x− ≤ ≤ and 0 y π≤ ≤ , then 1cosy x−= and cos y x= are equivalent.

Periodic functions A function f is called periodic if there is a positive number P

such that ( ) ( )+ =f x P f x whenever x and x P+ lie in the

domain of f.

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52

Subsidiary Mathematics Teacher’s Book Five

Any function which is not periodic is called aperiodic.

The period of sum, difference or product of trigonometric

function is given by the Lowest Common Multiple (LCM) of the

periods of each term or factor.

Teaching guidelines

Let learners know how to find domain of definition of a polynomial, rational and irrational functions. Recall that the domain of definition of a function is the set of elements where the function is defined.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

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53

Trigonometric Functions and their Inverses

Answers to activities and exercises

Activity 4.1 Page 78

Materials Exercise books, pens, calculators

Answers1. No value of x 2. No value of x

3. ,2

x k kπ π= + ∈ 4. ,x k kπ= ∈

Exercise 4.1 Page 81

1.

2. { }\ 0 3. { }\ 0

Activity 4.2 Page 82

Materials Exercise books, pens, calculators

Answers

1. ] [ ] [, 1 1,−∞ − ∪ +∞ 2. ] [ ] [, 1 1,−∞ − ∪ +∞

3. No value of x

Exercise 4.2 Page 88

1. 1 1,0 0,2 2

− ∪ 2. [ ]1,1−

3. ] ]0,1 4. [ [ ] ]1,0 0,1− ∪

Activity 4.3 Page 89

Materials Exercise books, pens

Answers

1. ( ) ( ) ( ) ( ) ( ) ( )sin sin, , ,x xf x f x f x f x f x f xx x

− = − = − − ≠ − − =

2. ( ) ( ) ( ) ( ) ( ) ( )cos cos, , ,x xg x g x g x g x g x g xx x

− = − − = − − = − − ≠

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54

Subsidiary Mathematics Teacher’s Book Five

Exercise 4.3 Page 901. Even 2. Odd 3. Odd

4. Neither even nor odd, 1 is in domain but -1 is

not in domain.

Activity 4.4 Page 91

Materials Exercise books, pens, calculators

Answers

1. 2 ,k kπ ∈ 2. 2 ,k kπ ∈ 3. ,k kπ ∈

Exercise 4.4 Page 94

1. π 2. 3π 3. 3π

4. 2π 5. 2wπ 6.

Activity 4.5 Page 94

Materials Exercise books, pens, calculators

Answers

1. 2π 2. π

Exercise 4.5 Page 97

1. π 2. 2π 3. 2π 4. 2 33π

4.2. Limits of trigonometric functions

Recommended teaching periods: 3 periodsThis section looks at the method used to find the limits of

trigonometric functions

0

sinlim 1x

xx→

=

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55

Trigonometric Functions and their Inverses

Teaching guidelines

Let learners know how to find the limits of polynomial,

rational and irrational functions. They also know trigonometric

identities.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 4.6 Page 97

Materials Exercise books, pens, calculators

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56

Subsidiary Mathematics Teacher’s Book Five

Answers

A. 1) 0

limsin sin 0 0→

= =x

x 2) 0

lim sin 0sin 0 0→

= =x

x x

3) 0lim cos cos 0 1

→= =

xx 4)

0

1lim→

= ∞x x

5) 0 0 0

cos 1lim lim lim cos 1→ → →

= = ∞× = ∞x x x

x xx x

B. 1)

x sin xx

x sin xx

1 0.841470985 -1 0.841470985

0.9 0.870363233 -0.9 0.870363233

0.8 0.896695114 -0.8 0.896695114

0.7 0.920310982 -0.7 0.920310982

0.6 0.941070789 -0.6 0.941070789

0.5 0.958851077 -0.5 0.958851077

0.4 0.973545856 -0.4 0.973545856

0.3 0.985067356 -0.3 0.985067356

0.2 0.993346654 -0.2 0.993346654

0.1 0.998334166 -0.1 0.998334166

0.01 0.999983333 -0.01 0.999983333

0.001 0.999999833 -0.001 0.999999833

0.0001 0.999999998 -0.0001 0.999999998

2) 0

sinlim 1x

xx+→

= 3) 0

sinlim 1x

xx−→

=

4) Since both limits on each side are equal to 1

then 0

sinlim 1x

xx→

=

Exercise 4.6 Page 104

1) 4π 2) 2 3) 0 4) 3

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57

Trigonometric Functions and their Inverses

Activity 4.7 Page 104

Materials Exercises book, pens, calculator

Answers

1. a) Let ( )1cos 1y −= − . This is equivalent

to cos 1,0y y π= − ≤ ≤ . The only value of y satisfying these conditions is π . So

( )1cos 1 π− − =

b) Let ( )1tan 1y −= − . This is equivalent to

tan 1,2 2

y yπ π= − − < < . The only value of

y satisfying these conditions is 4π

− . So

( )1tan 14π− − = −

c) Let ( )1csc 1y −= . This is equivalent to

sec 1, , 02 2

y y yπ π= − ≤ ≤ ≠ . The only value

of y satisfying these conditions is 2π . So

( )1csc 12π− =

d) Let 1 1cos2

y − =

. This is equivalent to 1cos ,02

y y π= ≤ ≤ . The only value of

y satisfying these conditions is 3π . So

1 1cos2 3

π− =

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58

Subsidiary Mathematics Teacher’s Book Five

2. a) ( ) ( )1 2 1

1lim cos 1 2 cos 1x

x π− −

→− = − =

b) ( ) ( )1 1

0lim tan 1 tan 1

4xx π− −

→− = − = −

c) 1

21

1 0lim cos I.C1 0x

xx

−=

− . Remove this I.C

21 1

1 1 1lim lim1 2 2x x

xx x→ →

−= = −

− −. But 1 1 2cos

2 3π− − =

.

Thus, 121

1 2lim cos1 3x

xx

π−

−=

d) ( )2

11

1 0lim I.Csin 1 0x

xx−→

−=

−. Remove this I.C

( )( )

2

11 1 1

2 2

1 2 2lim lim lim 21 1sin 121 1

x x x

x x xx

x xx

−→ → →

−= = = −

− − −−− −

Thus ( )2

11

1lim 2sin 1x

xx−→

−= −

Exercise 4.7 Page 105

1) 34π 2)

3) 34π

4) 4π

4.3. Differentiation of trigonometric functions and their inverses

Recommended teaching periods: 3 periodsThis section looks at the derivative of trigonometric functions

and their inverses.

Derivative of trigonometric functions

1. ( )sincos

d u duudx dx

= 2. ( )cossin

d u duudx dx

= −

3. ( ) 2tansec

d u duudx dx

= 4. ( ) 2cotcsc

d u duudx dx

= −

5. ( )secsec tan

d u duu udx dx

= 6. ( )csccsc cot

d u duu udx dx

= −

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59

Trigonometric Functions and their Inverses

Derivative of inverse trigonometric functions

1. ( )2

arcsin 11

d u dudx dxu

=−

2. ( )2

arccos 11

d u dudx dxu

= −−

3. ( )2

arctan 11

d u dudx u dx

=+

4. ( )2

arccot 11

d u dudx u dx

= −+

5. ( )2

arcsec 11

d u dudx dxu u

=−

6. ( )2

arccsc 11

d u dudx dxu u

= −−

Teaching guidelines

Let learners know trigonometric identities. The trigonometric identities will be used in this section

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

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60

Subsidiary Mathematics Teacher’s Book Five

Answers to activities and exercises

Activity 4.8 Page 106

Materials Exercise books, pens

Answers

1. 0x∀ ∈

( )0

0

0 0

0 0

0 0

00

0

0 0

0

0

0

0

0

0

0

0

0

0

0 0

0

sin sinsin ' lim

2cos sin2 2lim

2sin2lim cos lim

2

2sin2lim cos lim

2 22

sin2lim cos lim

22

cos 12

cos

x x

x x

x x x x

x x x x

x x x x

x xxx x

x x x x

x xx x

x xx x

x xx x

x x

x xx x

x x

x x

x

→ →

→ →

→ →

−=

+ −

=−

−+

=−

−+

=−

−+

=−

+ = ×

=

Thus, ( ), sin ' cosx x x∀ ∈ =

2. cos sin2

x xπ = −

( )/

/

/

cos sin2

cos2 2

cos2

sin

x x

x x

x

x

π

π π

π

= −

= − −

= − −

= −

Thus, ( ), cos ' sinx x x∀ ∈ = −

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61

Trigonometric Functions and their Inverses

Exercise 4.8 Page 107

1. 22 cos( 3)x x + 2. ( ) ( )2 2 26 cos 4 sin 4x x x+ +

3. 26 sin 3x x− 4. 26cos 2 sin 2x x−

Activity 4.9 Page 107

Materials Exercise books, pens

Answers

1. sintancos

xxx

=

( )

( ) ( )( )

( )

2

2

2 2

2

2

//

/ /

sintancos

sin cos sin coscos

cos cos sin sincos

cos sincos

1cos

xxx

x x x xx

x x x xx

x xx

x

=

−=

+=

+=

=

( ) 2

2

2

/ 1tancossec1 tan

xx

xx

=

=

= +

2. cot tan2

x xπ = −

( )/

/

2

2

cot ' tan2

2

cos2

1sin

x x

x

x

x

π

π

π

= −

− =

−=

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62

Subsidiary Mathematics Teacher’s Book Five

( )

( )

2

2

2

/ 1cotsin

csc

1 cot

xx

x

x

−=

= −

= − +

Exercise 4.9 Page 108

1. ( )2tan 1 tanx x x+ + 2. ( )23 1 tan 3 2x + +

3. ( )2 22 1 cot 5x x − + − 4. ( )24sin 1 cot 4 cos cot 4x x x x− + +

Activity 4.10 Page 108

Materials Exercise books, pens

Answers

1. 1sec

cosx

x=

( )

2

1sec ' 'cossin

cos1 sin

cos cossec tan

xx

xx

xx xx x

=

=

=

=

2. 1csc

sinx

x=

( )

2

1csc ' 'sincos

sin1 cos

sin sincsc cot

xxxx

xx x

x x

= −

=

−=

= −

Exercise 4.10 Page 109

1. ( ) ( )3sec 3 2 tan 3 2x x+ + 2. ( )2 csc 2 3 2 cot 2θ θ θ θ−

3. 412sec 3 tan 3x x

Activity 4.11 Page 109

Materials Exercise books, pens

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63

Trigonometric Functions and their Inverses

Answers

1. ( ) 1sinf x x−= for [ ]1,1x∈ − and sinx y= for

,2 2

y π π ∈ − where ( )y f x= .

( ) ( ) ( )

( )

11

2

2 1

2

1 1 1sin 'sin ' cos cos sin

1 since cos 1 sin1 sin sin

11

xy y x

x xx

x

−−

= = =

= = −−

=−

2. ( ) 1cosf x x−= for [ ]1,1x∈ − and cosx y= for [ ]0,y π∈

where ( )y f x=

( ) ( ) ( )

( )

11

2

2 1

2

1 1 1cos 'cos ' sin sin cos

1 since sin 1 cos1 cos cos

11

xy y x

x xx

x

−−

−= = =

−= = −

−=

Exercise 4.11 Page 111

1. 2

11x x −

2. 4

21

xx

3. 2

12x x−

− 4. 1

2 1 2x x−

Activity 4.12 Page 111

Materials Exercise books, pens

Answers

1. ( ) 1tanf x x−= for x∈ and tanx y= for ,2 2

y π π ∈ −

where ( )y f x= .

( ) ( ) ( )1

2 22 1

1 1 1 1tan 'tan ' 1 tan 11 tan tan

xy y xx

−−

= = = =+ ++

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64

Subsidiary Mathematics Teacher’s Book Five

2. ( ) 1cotf x x−= for x ∈ and cotx y= for ] [0,y π∈

where ( )y f x=

( ) ( ) ( )1

2 22 1

1 1 1 1cot 'cot ' 1 cot 11 cot cot

xy y xx

−−

− − −= = = =

+ ++

Exercise 4.12 Page 112

1. ( )( )1'

2 1f x

x x=

+ 2. ( ) 22

1 1'11

f xxx x

= ++−

3. ( ) 1'2 1

f xx x

−=

Activity 4.13 Page 113

Materials Exercise books, pens

Answers

1. ( ) 1secf x x−= for 1x ≤ − or 1x ≥ and

secx y= for [ ]0, ,2

y y ππ∈ ≠ where ( )y f x=

( ) ( )1

2

1 1 1sec 'sec ' sec tan 1

xy y y x x

− = = =−

2. ( ) 1cscf x x−= for 1x ≤ − or 1x ≥ and cscx y=

for , , 02 2

y yπ π ∈ − ≠ where ( )y f x=

( ) ( )1

2

1 1 1csc 'csc ' csc cot 1

xy y y x x

− − −= = =

Exercise 4.13 Page 114

1. ( ) 2

12 1x x x+ +

2. 2

125 1x x −

3. ( )2 4 2

21 2

xx x x

+ +

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65

Trigonometric Functions and their Inverses

Activity 4.14 Page 114

Materials Exercises book, pens

Answers

1. ( ) ( )' 4cos 4g x x= 2. ( )16sin 4x−

3. ( )64cos 4x− 4. ( )256sin 4x

5. ( )1024cos 4x

Exercise 4.14 Page 116

1. a) 2 3 4 2' tan 1, '' 2 tan 2 tan , ''' 6 tan 8 tan 2y x y x x y x x= + = + = + +

2 3 4 2' tan 1, '' 2 tan 2 tan , ''' 6 tan 8 tan 2y x y x x y x x= + = + = + +

b) ( ) ( )2 3' sec tan , '' sec 1 2 tan , ''' sec 6 tan 5 tany x x y x x y x x x= = + = +

( ) ( )2 3' sec tan , '' sec 1 2 tan , ''' sec 6 tan 5 tany x x y x x y x x x= = + = +

c) ( ) ( ) ( ) ( ) ( )2 2 2 2 2 3 2' 2 sin , '' 2sin 4 cos , ''' 12 cos 8 siny x x y x x x y x x x x= − = − − = − +

( ) ( ) ( ) ( ) ( )2 2 2 2 2 3 2' 2 sin , '' 2sin 4 cos , ''' 12 cos 8 siny x x y x x x y x x x x= − = − − = − +

d) 2 2 3

cos sin cos sin sin' , '' 2 2x x x x xy yx x x x x

= − = − − + ,

3 2 4

cos cos sin sin''' 6 3 6x x x xyx x x x

= − + + −

2. a) 12 cos 22

n nx π− +

b) 1 5 sin 5 sin2 2 2

n n nx xπ π + − +

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66

Subsidiary Mathematics Teacher’s Book Five

4.4. Applications

Activity 4.15 Page 116

Materials Exercises book, pens

AnswersBy reading text books or accessing internet, learners will discuss on harmonic motion and how differentiation of trigonometry functions is used to find velocity, acceleration and jerk of an object if the function representing its position is known.

If we have the function representing the position, say

( )S t , then:

࿌ the velocity of the object is dsvdt

=

࿌ the acceleration of the object is 2

2

d sadt

=

࿌ the jerk of the object is 3

3

d sjdt

=

Exercise 4.15 Page 118

1. a) 3m b) 9 msπ− c) 227 m

sπ−

d) 33

t ππ +

e) 32

Hz f) 23

2. a) amplitude mx is 4m

frequency f is 0.5 Hz

period T is 2

angular frequency ω is π

b) velocity is 4 sin4

dx tdt

ππ π = − +

acceleration 2

22 4 cos

4d x tdt

ππ π = − +

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67

Trigonometric Functions and their Inverses

c) displacement at 1t = is 2 2 mπ−

velocity at 1t = is 2 2 msπ−

acceleration at 1t = is 222 2 m

sπ−

d) the maximum speed 4 msπ

maximum acceleration 224 m

End of Unit Assessment Page 121

1. a) 23π

b) π c) 2π

d) not periodic e) π f) not period

2. a) neither even nor odd b) even c) odd

d) odd

3. a) 2 b) 32

c) 1 d) 2

e) 7 f) 23

g) 116

h) 119

i) 157

j) 12

k) 1 l) cos a

m) sin a− n) 0 o) 4 p) 0

q) 2 r) 12

s) 34

t) 12

u) 2

2π v) 0 w) 2

32

4. a) 23sec tan 10cscx x x+ b) 5 2 212 2 tan secx x x x x−− − −

c) 5cos 2 4csc cotx x x− d) ( )2

3cos 23 2cos

tt

− e) ( )248 sin 6 5x x− + f) ( ) ( )3 2 4 472 sin 2 1 cos 2 1x x x+ +

g) ( ) ( )324 cos 1 sin 2x x x− + h) ( )

2

2sin 4 4 2 3 cos 4sin 4

x x xx

− +

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68

Subsidiary Mathematics Teacher’s Book Five

i) 2

2

21

xx

− j)

2

11 x−

k) 2

24x x

− l)

2

2

11

xx x

m) 1sin x−

5. The amount of money in the bank account will

be increasing during the following intervals:

2.1588 5.3004t< < , 8.4420 10t< <

6. a) 3π

− b) 21 t− c) 2π

d) -1 e) 3π f)

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69

Unit 5 Vector Space of Real Numbers

Learner’s Book pages 123–150

Aim

Apply vectors of 3 to solve problems related to angles using

the scalar product in 3 and use the vector product to solve

also problems in 3 .

Objectives

After completing this unit, the learners should be able to:

࿌ find the norm of a vector.

࿌ calculate the scalar product of two vectors.

࿌ calculate the angle between two vectors.

࿌ apply and transfer the skills of vectors to other area of knowledge.

Materials Exercise books, pens, instrument of geometry, calculator

Contents5.1. Scalar product of two vectors

Recommended teaching periods: 3 periods

Scalar productThe scalar product of two vectors of space is the application

0 0E E× → .

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70

Subsidiary Mathematics Teacher’s Book Five

Algebraically, the scalar product of vectors ( )1 2 3, ,u a a a=

and

( )1 2 3, , v b b b=

of space is defined by 1 1 2 2 3 3u v a b a b a b⋅ = + +

.

Teaching guidelines

Let learners know how to find scalar product of two vectors and magnitude of a vector in two dimensions. In three dimensions, there is a third component, z

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 5.1 Page 124

Materials Exercise books, pens, calculators

Answers

a) -5 b) 2

Exercise 5.1 Page 1251. 26 2. -9 3. -195 4. -125

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71

Vector Space of Real Numbers

5.2. Magnitude (or norm or length) of a vector

Magnitude of a vector

The magnitude of the vector u

noted by u

is defined as its

length.

If ( ), ,u a b c=

then 2 2 2u a b c= + +

.

Distance between two points

The distance between two points ( )1 2 3, ,A a a a and ( )1 2 3, ,B b b b

denoted, ( ),d A B is

( ) ( ) ( ) ( )2 2 21 1 2 2 3 3,d A B AB b a b a b a= = − + − + −

Activity 5.2 Page 125

Materials Exercise books, pens, calculators

Answers

a) 5 2 b) 46

Exercise 5.2 Page 128

1. 7 2. 26 3. 610 4. 746

5.3. Angle between two vectors

Recommended teaching periods: 3 periods

Angle between two vectors u

and v

is such that

( )cos , u vu vu v

⋅=

Teaching guidelines

Let learners know how to find scalar product of two vectors

and magnitude of a vector in two dimensions. In three

dimensions, there is a third component, z

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72

Subsidiary Mathematics Teacher’s Book Five

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 5.3 Page 128

Materials Exercise books, pens, calculators

Answers

1. 21u v⋅ = −

2. 21u v =

3. ( )1cos 2 1 2 ,u v k k ku v

π π π− ⋅ = + = + ∈

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73

Vector Space of Real Numbers

Exercise 5.3 Page 132

1. a) 047.5 b) 047 c) 070.6 d) 031.7

2. a) 2 3 4cos , cos , cos29 29 29

α β γ= = =

b) 4 1 4cos , cos , cos17 17 3 17

α β γ−= = =

c) 1 2 14cos , cos , cos201 201 201

α β γ− −= = =

d) cos 1, cos 0, cos 0α β γ= = =

5.4. Vector product

Recommended teaching periods: 2 periodsThe vector product (or cross product or Gibbs vector product) of

( )1 2 3, ,u a a a=

and ( )1 2 3, ,v b b b=

is denoted and defined by

2 3 1 3 1 21 2 3

2 3 1 3 1 21 2 3

i j ka a a a a a

u v a a a i j kb b b b b b

b b b× = = − +

Or

2 3 1 3 1 2

2 3 1 3 1 2

, ,a a a a a a

u vb b b b b b

× = −

planeα

u v×

v

u

The vector product of any two vectors is perpendicular to each

of these vectors.

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74

Subsidiary Mathematics Teacher’s Book Five

Mixed product

The mixed product of the vectors ( )1 2 3, ,u a a a=

, ( )1 2 3, ,v b b b=

and ( )1 2 3, ,w c c c=

is denoted and defined by ( ), ,u v w u v w = ⋅ ×

Teaching guidelines

Let learners know how to find determinant of order three and

scalar product of two vectors.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 5.4 Page 132

Materials Exercise books, pens, calculators

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75

Vector Space of Real Numbers

Answers

1. Let ( ), ,w a b c=

be that vector. w

is

perpendicular to both ( )4,2,1u =

and

( )2,4,2v = −

if 4 2 0a b c+ + = and

2 4 2 0a b c− + + = . Solving we have

( )0,1, 2w = −

or any other multiple of this

vector.

2. 2 1 4 1 4 2

4 2 14 2 2 2 2 4

2 4 2

i j ki j k= − +

− −−

10 20j k= − +

3. Vector obtained in 2 is a multiple of vector

obtained in 1.

Exercise 5.4 Page 134

1. ( )2, 10,2− 2. ( )2, 2,0− − 3. ( )2, 10, 8− −

4. ( )1,1,3− 5. ( )2, 12,1−

Activity 5.5 Page 135

Materials Exercise books, pens

Answers

1. 2 3 1 3 1 2

2 3 1 3 1 2

, ,b b b b b bc c c c c c

or

( )2 3 2 3 1 3 1 3 1 2 1 2, ,b c c b b c c b b c c b− − + −

2. 2 3 1 3 1 21 2 3

2 3 1 3 1 2

, ,b b b b b b

a a ac c c c c c

or

( )1 2 3 1 2 3 2 1 3 2 1 3 3 1 2 3 1 2, ,a b c a c b a b c a c b a b c a c b− − + −

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76

Subsidiary Mathematics Teacher’s Book Five

Exercise 5.5 Page 1361. -16 2. -8 3. -82

4. 17 5. -7

5.5. Applications

Recommended teaching periods: 1 period

Work done as a scalar productIf a constant force F acting on a particle displaces it from A

to B , the work done is given by work done F AB= ⋅

Area of a parallelogram

Area of a parallelogram with vectors u

and v

as two adjacent

sides is S u v= ×

Area of a triangle

Thus, the area of triangle with vectors u

and v

as two sides is 12

S u v= ×

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77

Vector Space of Real Numbers

Volume of a parallelepiped

The volume of a parallelepiped which has vectors u

, v

and w

as three concurrent edges, where v

and w

define its base, is

given by

( )V u v w= ⋅ ×

Remember that if ( )1 2 3, ,u a a a=

, ( )1 2 3, ,v b b b=

and

( )1 2 3, ,w c c c=

, then ( )1 2 3

1 2 3

1 2 3

a a au v w b b b

c c c⋅ × =

.

If the parallelepiped is defined by four points ( )1 2 3, ,A a a a ,

( )1 2 3, ,B b b b , ( )1 2 3, ,C c c c and ( )1 2 3, ,D d d d , its volume is

( )V AD AB AC= ⋅ ×

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78

Subsidiary Mathematics Teacher’s Book Five

Volume of a triangular prismThe parallelepiped can be split into 2 triangular prism of equal

volume. Since the volume of a parallelepiped is the magnitude

of the mixed product, then the volume of a triangular prism is

equal to 12 of the magnitude of the mixed product.

1 2 3

1 2 3

1 2 3

12

a a aV b b b

c c c=

Volume of a tetrahedronThe parallelepiped can be split into 6 tetrahedra of equal

volume.

Since the volume of a parallelepiped is the magnitude of the

mixed product, then the volume of a tetrahedron is equal to 16

of the magnitude of the mixed product.

u

v

w

1 2 3

1 2 3

1 2 3

16

a a aV b b b

c c c=

RemarkA tetrahedron is also called triangular pyramid.

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79

Vector Space of Real Numbers

Teaching guidelines

Let learners know how to find scalar product, vector product, mixed product and magnitude of a vector.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 5.6 Page 137

Materials Exercise books, pens

AnswersIf a constant force F acting on a particle displaces it

from A to B, then,

( )( )cos

work done component of F Displacement

F AB

F AB

θ

= ⋅

= ⋅

= ⋅

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80

Subsidiary Mathematics Teacher’s Book Five

Exercise 5.6 Page 1381. 16 unit of work 2. 55 unit of work

3. 1412

unit of work 4. 20 unit of work

Activity 5.7 Page 139

Materials Exercise books, pens

AnswersSince the base and the height of this parallelogram

are u

and sinv θ

respectively, the area is

sinS u v θ=

. But sinu v u vθ = ×

.

Then area is S u v= ×

.

Thus, the magnitude of the vector product of

two vectors u

and v

represents the area of a

parallelogram with vectors u

and v

as two adjacent

sides.

Exercise 5.7 Page 141

1. a) 220 2 Sq. units b) 445 Sq. units

2. 3 2

2 Sq. units

3. 29 Sq. units

4. 62

Sq. units

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81

Vector Space of Real Numbers

Activity 5.8 Page 141

Materials Exercise books, pens

AnswersThe base of this parallelepiped is defined by the

vectors v

and w

. Then, the area of the base is

sinS v w v w α= × =

.

The height of this parallelepiped is a

.

Since the vector a

is not known we can

find the height in terms of u

. We see that

cos cosa

a uu

θ θ= ⇔ =

.

The angle θ is the angle between the vector a

and

vector u

but it is also the angle between the vector

u

and the vector given by the vector product v w×

since this cross product is perpendicular to both v

and w

.

Now, the volume of the parallelepiped is product of

the area of the base and the height.

Then,

sin cosV v w uα θ=

sin cosV v w u α θ⇔ =

( )sin cosV u v w α θ⇔ =

cosV u v w θ⇔ = ×

( )V u v w⇔ = ⋅ ×

Thus the volume of a parallelepiped which has vectors u

, v

and w

as three concurrent edges, where v

and w

define its base, is given by

( )V u v w= ⋅ ×

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82

Subsidiary Mathematics Teacher’s Book Five

Exercise 5.8 Page 147

1. a) 32

cubic units b) 352

cubic units

2. a) 2 cubic units b) 103

cubic units

3. 20 cubic units 4. 173

cubic units

End of Unit Assessment Page 149

1. a) 0 b) k

c) j−

d) i

e) 0 f) 0

2. a) 7 sq. units b) 30 sq. units

c) 15 sq. units d) 7 3 sq. units

3. a) 20 b) 13 c) 39

4. a) ( )20, 67, 9− − − b) ( )78,52, 26− −

c) ( )24,0, 16− d) ( )12, 22, 8− − −

e) ( )0, 56, 392− − f) ( )0,56,392

5. a) 3742

sq. units b) 9 13 sq. units

6. ambiguous, needs parentheses

7. a) 16 cubic units b) 45 cubic units

8. a) 9 cubic units b) 122 sq. units

9. a) 9 22

sq. units b) 2 2 2 2 2 212

b c c a a b+ + sq. units

10. ( ) ( ) ( )2 2 21 2 2 1 1 2 2 1 1 2 2 1

12

y z y z z x z x x y x y− + − + −

11. 6 cubic units

12. 077.88

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83

Unit 6 Matrices and Determinant of Order 3

Learner’s Book pages 151–182

Aim

Apply matrix and determinant of order 3 to solve related

problems.

Objectives

After completing this unit, the learners should be able to:

࿌ define and give example of matrix of order three.

࿌ perform different operations on matrices of order three.

࿌ find the determinant of order three.

࿌ find the inverse of matrix of order three.

࿌ solve system of three linear equations by matrix inverse method.

Materials Exercise books, pens, calculators

Contents6.1. Square matrices of order three

Recommended teaching periods: 6 periodsThis section looks at the definition of square matrices of order

three and their operations:

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84

Subsidiary Mathematics Teacher’s Book Five

࿌ Addition and subtraction (only matrices of the same type can be subtracted)

If 11 12 13

21 22 23

31 32 33

a a aA a a a

a a a

=

and 11 12 13

21 22 23

31 32 33

b b bB b b b

b b b

=

, then

11 12 13 11 12 13 11 11 12 12 13 13

21 22 23 21 22 23 21 21 22 22 23 23

31 32 33 31 32 33 31 31 32 32 33 33

a a a b b b a b a b a bA B a a a b b b a b a b a b

a a a b b b a b a b a b

+ + + + = + = + + + + + +

11 12 13 11 12 13 11 11 12 12 13 13

21 22 23 21 22 23 21 21 22 22 23 23

31 32 33 31 32 33 31 31 32 32 33 33

a a a b b b a b a b a bA B a a a b b b a b a b a b

a a a b b b a b a b a b

− − − − = − = − − − − − −

࿌ Transpose

If 11 12 13

21 22 23

31 32 33

a a aA a a a

a a a

=

, then 11 21 31

12 22 32

13 23 33

t

a a aA a a a

a a a

=

Properties of transpose of matrices

1. ( ) ttA A= 2. ( ) t t tA B A B+ = +

3. ( ) · · t tA Aα α=

MultiplicationTwo matrices A and B can be multiplied together if and only if

the number of columns of A is equal to the number of rows of

B.

m n n p m pM M M× × ×× =

11 12 13 11 12 13

21 22 23 21 22 23

31 32 33 31 32 33

11 11 12 21 13 31 11 12 12 22 13 32 11 13 12 23 13 33

21 11 22 21 23 31 21 12 22 22 23 32 21 13 22 23 23 33

a a a b b bA B a a a b b b

a a a b b b

a b a b a b a b a b a b a b a b a ba b a b a b a b a b a b a b a b a b

× = ×

+ + + + + += + + + + + +

31 11 32 21 33 31 31 12 32 22 33 32 31 13 32 23 33 33a b a b a b a b a b a b a b a b a b

+ + + + + +

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85

Matrices and Determinant of Order

Properties of multiplication of matricesLet A,B,C be matrices of order three

1. Associative

( ) ( )A B C A B C× × = × ×

2. Multiplicative Identity

A I A× = , where I is the identity matrix with the same

order as matrix A.

3. Not Commutative

A B B A× = ×

4. Distributive

( )A B C A B A C× + = × + ×

5. ( )t t tA B B A× = ×

Notice

࿌ If 0AB = , it does not necessarily follow that 0A = or 0B = .

࿌ Commuting matrices in multiplication

In general the multiplication of matrices is not

commutative, i.e, AB BA≠ , but we can have the case

where two matrices A and B satisfy AB BA= . In this

case, A and B are said to be commuting.

Teaching guidelines

Let learners know what square matrix of order two is. Square matrix of order three will have three rows and three columns.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

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86

Subsidiary Mathematics Teacher’s Book Five

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 6.1 Page 152

Materials Exercise books, pens

Answers

12 0 53 2 16 2 0

xyz

− − −

Exercise 6.1 Page 154

1. a) 2 3 112 13 10 11 1

, 1 23 241 43 441 1 2

, 0 1 121 20 40 18 6

,

4 2 19 1 0

7 0 1

− −

, 3 9 25 6 47 3 8

b) 1 2 4

0 4 00 0 1

, 1 1 5

0 3 10 0 2

− −

,

11 2 70 10 90 0 3

,

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87

Matrices and Determinant of Order

8 2 30 9 50 0 4

− −

, 2 2 30 4 50 0 7

c) 1 0 0

0 4 00 0 1

,

1 0 00 3 00 0 2

, 1 0 00 10 00 0 6

,

3 0 00 1 00 0 3

, 4 0 00 1 00 0 6

There are many possible answers

2. 5, 2x y= = −

Activity 6.2 Page 155

Materials Exercise books, pens, calculators

Answers

1. 7 2 20 10 76 0 2

2.

0 4 30 1 05 0 3

− −

3.

0 0 00 0 00 0 0

4. 3 2 00 4 34 0 0

and

3 2 00 4 34 0 0

. Addition of matrices is

commutative

5. 4 4 15 5 55 4 0

and

4 4 15 5 55 4 0

. Addition of matrices

is associative

6. 1 0 32 1 01 1 1

, 2 0 10 3 01 2 1

, and 1 5 12 1 41 2 0

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88

Subsidiary Mathematics Teacher’s Book Five

Exercise 6.2 Page 157

1. 5 2 18 5 53 2 2

− −

2.

3 0 11 2 21 3 1

3.

6 8 613 15 40 6 4

− − − −

Activity 6.3 Page 158

Materials Exercise books, pens, calculators

Answers

1.

3 1 2 0 1 23 1 2 , 1 1 11 1 1 1 1 0

− − − − − −

2.

3 2 04 2 30 2 1

− −

3. 3 4 02 2 20 3 1

− −

4.

3 2 04 2 30 2 1

− −

5. Matrices obtained in 2 and 4 are the same

6.

3 1 2 3 3 13 1 2 , 1 1 11 1 1 2 2 1

− − − −

The second matrix is

equal to matrix A

Exercise 6.3 Page 159

1.

1 3 32 1 02 4 3

2.

1 4 91 1 3

6 5 5

− −

3.

3 16 121 3 148 5 2

− − − − −

4.

21 2 4 1 2 1 2 44 1 0 , 4 1 0 4 1 01 1 8 1 3 8 1 1 8

t

xM

x

= =

+

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89

Matrices and Determinant of Order

2 42

3 1x

xx

=⇒ = −

+ =

Activity 6.4 Page 159

Materials Exercise books, pens, calculators

Answers

1 1 1 1 1 12 1 2 1 2 30 3 1 1 0 2

A B− −

× = × − −

( ) ( )( ) ( )

( ) ( ) ( ) ( ) ( )

1 1 1 1 1 1 1 1 1 2 1 0 1 1 1 3 1 22 1 1 1 2 1 2 1 1 2 2 0 2 1 1 3 2 2

0 1 3 1 1 1 0 1 3 2 1 0 0 1 3 3 1 2

− × + × + × − − × + × + × − × − + × + × = × + × + × − × + × + × × − + × + × × + × + − × − × + × + − × × − + × + − ×

( ) ( )( ) ( )

( ) ( ) ( ) ( ) ( )

1 1 1 1 1 1 1 1 1 2 1 0 1 1 1 3 1 22 1 1 1 2 1 2 1 1 2 2 0 2 1 1 3 2 2

0 1 3 1 1 1 0 1 3 2 1 0 0 1 3 3 1 2

− × + × + × − − × + × + × − × − + × + × = × + × + × − × + × + × × − + × + × × + × + − × − × + × + − × × − + × + − ×

1 1 61 4 34 6 7

− =

Exercise 6.4 Page 161

1.

28 36 3928 6 556 64 80

A B−

× = − −

2.

47 4 361 9 31

112 8 28A C

− × = − −

3.

161 9 21276 22 18123 7 17

B C−

× = − − −

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90

Subsidiary Mathematics Teacher’s Book Five

Activity 6.5 Page 161

Materials Exercise books, pens, calculators

Answers

1.

1 3 2 2 4 12 1 3 7 7 2

1 1 2 5 3 1A B , B A

− − − − × = − − × = − − − −

A B B A× ≠ × .

Multiplication of matrices is not commutative

2. ( )1 2 1 1 2 1

3 1 1 3 1 12 3 2 2 3 2

t t tA B , B A− − − −

× = − × = − − − − −

( )t t tA B B A× = ×

3. ( )3 0 1 2 3 1 4 9 40 1 1 4 3 0 6 3 12 3 2 2 0 1 4 3 0

A B C− −

× × = − − = − − − −

,

( )1 3 2 1 1 1 4 9 42 1 3 1 2 1 6 3 1

1 1 2 1 1 0 4 3 0A B C

− − − − × × = − − − = − − − −

( ) ( )A B C A B C× × = × × .

Multiplication of matrices is associative

4. ( )3 0 1 1 2 2 1 7 50 1 1 2 1 1 4 2 22 3 2 2 1 1 0 5 3

A B C− −

× + = − − − = − − − −

,

1 3 2 2 4 3 1 7 52 1 3 2 3 1 4 2 2

1 1 2 1 6 5 0 5 3A B A C

− − − − × + × = − − + − − = − − − − −

( )A B C A B A C× + = × + × .

Multiplication of matrices is distributive over

addition

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91

Matrices and Determinant of Order

Exercise 6.5 Page 164

1. 3 0 2 2 0 24 0 0 1 0 1

0 0 0 1 0 1A B , B A

− − − × = − × = − −

2. ( )3 0 2 1 0 1 5 2 34 0 0 2 2 0 4 0 4

0 0 0 1 1 0 0 0 0A B C

− − − × × = − − = − −

( )1 0 1 3 1 2 5 2 31 1 1 1 2 1 4 0 40 0 0 2 1 1 0 0 0

A B C− −

× × = − − − = − −

3. ( )1 0 1 1 0 0 3 1 11 1 1 1 2 2 2 1 10 0 0 2 1 1 0 0 0

A B C− −

× + = − − = − − − −

,

3 0 2 0 1 1 3 1 14 0 0 2 1 1 2 1 1

0 0 0 0 0 0 0 0 0A B A C

− − − × + × = − + − − = − − −

4. ( )3 0 24 0 0 3

0 0 0tr A B tr

− × = − = −

6.2. Determinant of order three

Recommended teaching periods: 10 periodsThis section looks the method used to find the determinant of order three: Rule of SARRUS. It looks the general method used to find determinant of order 2n ≥ (cofactor method). It also looks how to find the inverse of a square matrix of order three.

To calculate the 3x3 determinant we rewrite the first two rows below the determinant (or first two columns to the right of the determinant).

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Subsidiary Mathematics Teacher’s Book Five

11 22 33 21 32 13 31 12 23 31 22 13 11 32 23 21 12 33det a a a a a a a a a a a a a a a a a a= + + − − −

Or

11 22 33 12 23 31 13 21 32 31 22 13 32 23 11 33 21 12det a a a a a a a a a a a a a a a a a a= + + − − −

General rule for n n× matrices (minor and cofactor)General method of finding the determinant of matrix with n n×

dimension ( )2 2, 3 3, 4 4, 5 5,× × × × … is the use of cofactors.

MinorAn element, ija , to the value of the determinant of order 1n − ,

obtained by deleting the row i and the column j in the matrix

is called a minor.

CofactorThe cofactor of the element ija is its minor prefixing:

The + sign if i+j is even.

The − sign if i+j is odd.

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93

Matrices and Determinant of Order

The value of a determinant is equal to the sum of the products

of the elements of a line (row or column) by its corresponding

cofactors:

11 12 1322 23 21 23 21 22

21 22 23 11 12 1332 33 31 33 31 32

31 32 33

a a aa a a a a a

A a a a a a aa a a a a a

a a a= = − +

Teaching guidelines

Let learners know how to find determinant of order two. For

determinant of order three, we have three rows and three

columns.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

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94

Subsidiary Mathematics Teacher’s Book Five

Answers to activities and exercises

Activity 6.6 Page 164

Materials Exercise books, pens, calculators

Answers

1. ( ) ( ) ( )( ) ( ) ( ) ( )( )1 6 1 3 0 2 5 1 4 2 6 5 1 0 1 1 3 4 62× × + × × + × × − − × × − × × − × × − = −

2. ( ) ( )( ) ( ) ( ) ( ) ( )( )10 2 4 6 5 2 0 3 1 4 5 0 2 3 10 1 6 2 70× × + − × × + × × − × × − × × − × − × = −

Exercise 6.6 Page 1671) 9 2) 6 3) 8

Activity 6.7 Page 168

Materials Exercise books, pens, calculators

Answers

1. 0, 0A B= =

2. ( )36, 6 6 36C D C D⋅ = − ⋅ = × − = −

C D C D⋅ = ⋅

Determinant of product is equal to the product

of determinants.

3. Product of leading diagonal elements

1 2 3 6× × = , 6C =

Determinant of a triangular matrix is equal to

the product of leading diagonal elements.

Exercise 6.7 Page 171

1. 0A = 2. 0B = 3. 14C =

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95

Matrices and Determinant of Order

Activity 6.8 Page 171

Materials Exercise books, pens, calculators

Answers

1. 1A = −

2. Cofactor of each element:

( ) ( ) ( )( ) ( ) ( )( ) ( ) ( )

1 3, 1 5, 1 1

2 1, 1 2, 1 1

3 2, 2 3, 1 1

cofactor cofactor cofactor

cofactor cofactor cofactor

cofactor cofactor cofactor

= = − =

= = − − =

= − = = −

Cofactor matrix

3 5 11 2 12 3 1

− − − −

3. Transpose of cofactor matrix is

3 1 25 2 3

1 1 1

− − − −

4. 3 1 2 3 1 2

1 5 2 3 5 2 31

1 1 1 1 1 1

− − − − − = − − − − −

5. 1 0 00 1 00 0 1

, the obtained product is the

identity matrix.

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Subsidiary Mathematics Teacher’s Book Five

Exercise 6.8 Page 174

1. No inverse 2.

23 29 5268 268 268

3 37 11268 268 2689 23 33

268 268 268

− − − −

3.

6 45 167 14 75 24 187 7 7

1 11 57 14 7

− − − −

4.

2 3 15 5

1 4 15 56 29 85 5

− − − − −

6.3. Applications

Recommended teaching periods: 2 periodsThis section looks at how to solve a system of three linear

equations by matrix inverse and by Cramer’s rule method.

Consider the following simultaneous linear equations.

11 12 13 1

21 22 23 2

31 32 33 3

a x a y a z ca x a y a z ca x a y a z c

+ + = + + = + + =

One of the methods of solving this, is the use Cramer’s rule.

11 12 13

21 22 23

31 32 33

0∆ = ≠a a aa a aa a a

1 12 13

2 22 23

3 32 33

x

c a ac a ac a a

∆ =

11 1 13

21 2 23

31 3 33

y

a c aa c aa c a

∆ =

11 12 1

21 22 2

31 32 3

z

a a ca a ca a c

∆ =

, yxx y∆∆

= =∆ ∆

and zz ∆=

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97

Matrices and Determinant of Order

Remember that if 0∆ = , there is no solution or infinity of

solution

Teaching guidelines

Let learners know how to rewrite a system of linear equation in matrix form, how to find inverse of matrix and how to multiply to matrices of oder two.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 6.9 Page 174

Materials Exercise books, pens

Answers

1. 111 12 13

21 22 23 2

31 32 33 3

ca a a xa a a y ca a a x c

=

2.

1 1111 12 13 11 12 13 11 12 13

21 22 23 21 22 23 21 22 23 2

31 32 33 31 32 33 31 32 33 3

ca a a a a a x a a aa a a a a a y a a a ca a a a a a x a a a c

− − =

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Subsidiary Mathematics Teacher’s Book Five

1111 12 13

21 22 23 2

31 32 33 3

cx a a ay a a a cx a a a c

− =

Exercise 6.9 Page 178

1. ( ){ }0,0,0S = 2. { }S = 3. ( ){ }1,2,0S =

End of Unit Assessment Page 182

1. a)

7 3 00 4 120 10 2

− − − − −

b)

9 23 60 4 164 2 8

− − − − − −

c)

7 8 32 4 102 14 7

− −

d)

29 28 1510 34 21

4 28 16

− − − −

e)

38 36 131 12 42

0 0 18

− − −

f)

118 120 3719 12 1014 0 76

2. a)

1 0 01 1 0

0 1 1

− −

b) no inverse

c)

44 8 1207 207 691 19 11

207 207 6913 40 5207 207 69

− − − −

3. 3 2 25 5 2

5 3 1X

− − = − −

4. a) ( ){ }0,0,0S = b) ( ){ }1,1,1S = c) ( ){ }3,0,1S =

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99

Unit 7 Bivariate Statistics

Learner’s Book pages 183–212

Aim

Extend understanding, analysis and interpretation of bivariate

data to correlation coefficients and regression lines.

Objectives

After completing this unit, the learners should be able to:

࿌ find the covariance of two quantitative variables.

࿌ determine the linear regression line of a given series.

࿌ calculate a linear correlation coefficient of a given double series and interpret it.

Materials Exercise books, pens, calculators

Contents7.1. Covariance

Recommended teaching periods: 2 periodsThis section looks at formula used to find the covariance of two

variable x and y.

( )1

1cov ,k

i i ii

x y f x y x yn =

= −∑

Teaching guidelines

Let learners know how to find variance and standard deviation of a series. In bivariate statistics we use two series.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

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Subsidiary Mathematics Teacher’s Book Five

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 7.1 Page 184

Materials Exercise books, pens

Answers

i ix iy ix x− iy y− ( )( )i ix x y y− −

1 3 6 0.5 0.5 0.252 1 1 -1.5 -4.5 6.753 4 3 1.5 -2.5 -3.754 3 8 0.5 2.5 1.255 2 7 -0.5 1.5 -0.756 2 8 -0.5 2.5 -1.25

6

115i

ix

=

=∑6

133i

iy

=

=∑

( )( )6

12.5i i

ix x y y

=

− − =∑

2.5x = 5.5y =

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101

Bivariate Statistics

1. If you divide by total frequency you get variance

2. If you divide by total frequency you get

covariance

Exercise 7.1 Page 188

1. ( )cov , 5x y = 2. ( ) 71cov ,12

x y =

3. ( )cov , 98.75x y =

7.2. Regression lines

Recommended teaching periods: 5 periodsThis section looks at the adjustment of algebraic expression of

two regression lines.

The regression line y on x is written as

( ) ( )/ 2

cov ,y x

x

x yL y y x x

σ≡ − = −

The regression line x on y is written as

( ) ( )/ 2

cov ,x y

y

x yL x x y y

σ≡ − = −

Teaching guidelines

Let learners know how to find mean, standard deviation and covariance.

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

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102

Subsidiary Mathematics Teacher’s Book Five

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 7.2 Page 189

Materials Exercise books, pens

Answers

1. ( )( )/

12 1

k

b i ii

D y ax b=

= − − −∑ or ( )/

12

k

b i ii

D y ax b=

= − − −∑

2. ( )1

0k

i ii

y ax b=

− − =∑ or 1 1 1

0k k k

i ii i i

y ax b= = =

− − =∑ ∑ ∑

or 1 1 1

k k k

i ii i i

b y ax= = =

= −∑ ∑ ∑

Dividing both sides by n gives

1 1 1

1 1 1k k k

i ii i i

b y axn n n= = =

= −∑ ∑ ∑ or

1 1 1

11k k k

i ii i i

b ay xn n n= = =

= −∑ ∑ ∑ or b y ax= −

3. ( ) ( )22

1 1

k k

i i i ii i

y ax b y ax y ax= =

− − = − − +∑ ∑

Or

( ) ( ) ( ) 22

1 1

k k

i i i ii i

y ax b y y a x x= =

− − = − − − ∑ ∑

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103

Bivariate Statistics

Differentiation with respect to a and

equating to zero:

( ) ( ) ( )1

2 0k

i i ii

y y a x x x x=

− − − − − = ∑

( ) ( ) ( )1

2 0k

i i ii

y y a x x x x=

− − − − − = ∑

( ) ( ) ( )1

0k

i i ii

y y a x x x x=

⇔ − − − − = ∑

( )( ) ( )2

10

k

i i ii

x x y y a x x=

⇔ − − − − = ∑

( )( ) ( )2

1 10

k k

i i ii i

x x y y a x x= =

⇔ − − − − =∑ ∑

( ) ( )( )2

1 1

k k

i i ii i

a x x x x y y= =

⇔ − = − −∑ ∑

( ) ( )( )2

1 1

k k

i i ii i

a x x x x y y= =

⇔ − = − −∑ ∑

Dividing both sides by n gives

( ) ( )( )2

1 1

1k k

i i ii i

a x x x x y yn n= =

⇔ − = − −∑ ∑

( )( )

( )1

2

1

1

1

k

i ii

k

ii

x x y yna

x xn

=

=

− −⇒ =

∑4. The variance for variable x is

( )22

1

1 k

x ii

x xn

σ=

= −∑ and the variance for

variable y is ( )22

1

1 k

y ii

y yn

σ=

= −∑ and the

covariance of these two

variables is ( ) ( )( )1

1cov ,k

i ii

x y x x y yn =

= − −∑Then

( )2

cov ,

x

x ya

σ=

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104

Subsidiary Mathematics Teacher’s Book Five

5. Now, we have that the regression line y on x is

y ax b= + , where

( )2

cov ,

x

x ya

b y ax

σ

= = −Or

( ) ( )2 2

cov , cov ,

x x

x y x yy x y x

σ σ

= + −

Exercise 7.2 Page 194

1. a) 0.19 8.098y x= − b) 4.06y =

2. 5.6 163.3, 0.06 21.8x y y x= − + = − +

7.3. Coefficient of correlation

Recommended teaching periods: 3 periodsThis section looks at the correlation coefficient and its properties.

It also looks at the Spearman’s coefficient of rank correlation.

The Pearson’s coefficient of correlation also called product moment coefficient of correlation or simply coefficient of correlation, denoted by r, is a measure of the strength of linear relationship between two variables.

The correlation coefficient between two variables x and y is

given by ( )cov ,

x y

x yr

σ σ= .

The Spearman’s coefficient of rank correlation is given by

( )

2

12

61

1

k

ii

d

n nρ == −

Where, d refers to the difference of ranks between paired items

in two series.

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105

Bivariate Statistics

Teaching guidelines

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 7.3 Page 195

Materials Exercise books, pens, calculators

Answers

1. 3.3, 3.4x yσ σ= = 2. ( )cov , 4.1x y =

3. ( )( )( )

cov , 4.1 0.373.3 3.4x y

x yσ σ

= =

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106

Subsidiary Mathematics Teacher’s Book Five

Exercise 7.3 Page 2041. r = 0.9, as the correlation coefficient is very close

to 1, the correlation is very strong.

2. 0.94r = , as the correlation coefficient is very

close to 1, the correlation is very strong.

3. 0.26r = − , as the correlation coefficient is very

close to 0, the correlation is very weak.

7.4. Applications

Activity 7.4 Page 205

Materials Exercises book, pens

AnswersBy reading textbooks or accessing internet, learners

will discuss how bivariate statistics is used in daily

life. Bivariate statistics can help in prediction of a

value for one variable if we know the value of the

other by using regression lines.

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107

Bivariate Statistics

End of Unit Assessment Page 208

1. Data set 1

a) 4.50 0.64y x= + b) 4.42 0.75x y= +

Data set 2

a) 90.31 1.78y x= − b) 37.80 0.39x y= −

2. 2.59 0.65 ;36.5y x= − +

3. 0.918, 65.45 0.981( 65.18), 65.18 0.859( 65.45)r y x x y= − = − − = −

4. 0.611 10.5, 1.478 1.143, 28.83y x x y y= + = − =

5. 0.94 92.26, 134.56y x Blood pressure= + =

6. 3.8 1.6 , 2.06 0.59y x x y= + = − +

7. 8 1.2y x= − +

8. 15, 5c d= = −

9. 0.60, 0.89 76w h= −

10. 3 15 3, ,

29 29 4x y r= − = =

11. 0.4r =

12. 0.82

13. 0.77

14. 0.415−

15. a) 0.954 b) 2x = , 3y =

16. 13, 17, 0.8 6.6, 0.45 5.35, 0.6, 4yx y y x x y r σ= = = + = − = =

17. 13, 17, 4yx y σ= = =18. 0.26

19. a) 0.43b) Somme agreement between average attendances

ranking a position in league, high position in

league correlating with high attendance.

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108

Subsidiary Mathematics Teacher’s Book Five

20. a) (i) 0.976− (ii) 0.292( 0.292)or−

b) The transport manager’s order is more profitable

for the seller, saleswomen is unlikely to try to

dissuade.

c) (i) No, maximum value is 1

(ii) Yes, higher performing cars generally do

less mileage to the gallon.

(iii) No, the higher the engine capacity, the

dearer the car.

d) When only two rankings are known; when

relationship is non-linear.

21. a) There is a strong positive correlation

b) 54.5

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109

Unit 8 Conditional Probability and Bayes Theorem

Learner’s Book pages 213–230

Aim

Solve problems using Bayes theorem and use data to make

decisions about likelihood and risk.

Objectives

After completing this unit, the learners should be able to:

࿌ use tree diagram to find probability of events.

࿌ find probability of independent events.

࿌ find probability of one event given that the other event has occurred.

࿌ use and apply Bayes theorem.

Materials Exercise books, pens, ruler, calculator

Contents8.1. Tree diagram

Recommended teaching periods: 3 periodsThis section shows the method used to find probability of events

by constructing tree diagram.

A tree diagram is a means which can be used to show the

probabilities of certain outcomes occurring when two or more

trials take place in succession.

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110

Subsidiary Mathematics Teacher’s Book Five

The outcome is written at the end of the branch and the fraction

on the branch gives the probability of the outcome occurring.

For each trial the number of branches is equal to the number

of possible outcomes of that trial. In the diagram there are two

possible outcomes, A and B, of each trial.

Teaching guidelines

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 8.1 Page 214

Materials Exercise books, pens, calculators

MethodologyFacilitate learners in Group work, then questioning.

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111

Conditional Probability and Bayes Theorem

Answers

1. Total number of balls is 8. There are 5 red balls

and 3 green balls, then probability of choosing a

red ball is 58

and probability of choosing a green

ball is 38

2. Since after the first draw the ball is replaced in

the bag, we have the same number of balls as

in question 1. The total number of balls is 8.

There are 5 red balls and 3 green balls, then

probability of choosing a red ball is 58

and

probability of choosing a green ball is 38

3. Complete figure:

Exercise 8.1 Page 216

1. a) 1564

b) 1532

c) 1732

2. a) ( ) 10 9 83boys 0.21416 15 14

P = × × =

b) ( ) 10 9 6 10 6 9 6 10 92 boys and 1 girl 0.48216 15 14 16 15 14 16 15 14

P = × × + × × + × × =

c) ( ) 10 6 5 6 10 5 6 5 102 girls and 1 boy 0.26816 15 14 16 15 14 16 15 14

P = × × + × × + × × =

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112

Subsidiary Mathematics Teacher’s Book Five

d) ( ) 6 5 43girls 0.035716 15 14

P = × × =

3. a) 49

100 b)

9100

8.2. Independent events

Recommended teaching periods: 3 periodsThis section shows the formula used to find probability of

independent events.

If probability of event B is not affected by the occurrence

of event A, events A and B are said to be independent and

( ) ( ) ( )P A B P A P B∩ = ×

This rule is the simplest form of the multiplication law of

probability.

Teaching guidelines

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

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113

Conditional Probability and Bayes Theorem

Answers to activities and exercises

Activity 8.2 Page 216

Materials Exercise books, pens

Answers

The occurrence of the event for the second selection

is not affected by the event for the first selection

because for the first selection the book is replaced. It

means that the sample space does not change.

Exercise 8.2 Page 218

1. ( ) 1 1 1red and red5 5 25

P = × =

2. ( ) 1 1 1head and 32 6 12

P = × =

8.3. Conditional probability

Recommended teaching periods: 3 periodsThis section shows the formula used to find conditional

probability.

The probability of an event B given that event A has occurred

is called the conditional probability of B given A and is written

( )|P B A .

In this case, ( )|P B A is the probability that B occurs considering

A as the sample space, and since the subset of A in which B

occurs is A B∩ , then

( ) ( )( )

|P B A

P B AP A

∩=

From this result, we have a general statement of the

multiplication law: ( ) ( ) ( )|P A B P A P B A∩ = ×

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114

Subsidiary Mathematics Teacher’s Book Five

Teaching guidelines

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 8.3 Page 219

Materials Exercise books, pens

Answers

The occurrence of the event for the second selection

is affected by the event for the first selection because

for the first selection the book is not replaced. It

means that the sample space has been changed.

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115

Conditional Probability and Bayes Theorem

Exercise 8.3 Page 223

1. 12

2. ( )1

166 | 3 36

P even = =

3. ( ) ( )( )

0.34| 0.720.47

P Black and WhiteP White Black

P Black= = =

8.4. Bayes theorem and applications

Recommended teaching periods: 5 periodsThis section shows how to find probability of events using

Bayes theorem and its applications.

Let 1 2 3, , ,..., nB B B B be incompatible and exhaustive events and

let A be an arbitrary event.

We have:

( ) ( )( )

( ) ( )

( ) ( )1

||

|

i i ii n

i ii

P B A P A B P BP B A

P A P A B P B=

∩= =

This formula is called Bayes’ formula.

Remark

We also have (Bayes’ rule)

( ) ( ) ( )( )

||

P A B P BP B A

P A=

Teaching guidelines

࿌ Organise class into groups. Request each group to have a group leader who will present their findings to the class.

࿌ Ask each group to do activity related to the lesson they are going to learn. The learners may need your assistance to do any activity. Help them to understand the activity. After group discussion, invite some or all groups for presentation of their work.

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116

Subsidiary Mathematics Teacher’s Book Five

࿌ After activity presentation, capture the main points from the presentation of the learners and summarise them. Guide the learners through given examples in Learner’s book or through your own examples.

࿌ Ask learners what they learned in day lesson to ensure that they understood what they have learned.

࿌ Request learners to do exercises in their respective groups. Request learners to correct exercises on chalkboard and give them individual evaluation. Remember to give them homework.

Answers to activities and exercises

Activity 8.4 Page 223

Materials Exercise books, pens

Answers

1. ( ) ( ) ( ) ( ) ( ) ( ) ( )1 1 2 2 3 3| | |P A P A B P B P A B P B P A B P B= + +

2. ( ) ( )( )

( ) ( )( ) ( ) ( ) ( ) ( ) ( )

1 1 11

1 1 2 2 3 3

||

| | |P B A P A B P B

P B AP A P A B P B P A B P B P A B P B

∩= =

+ +

( ) ( )( )

( ) ( )( ) ( ) ( ) ( ) ( ) ( )

2 2 22

1 1 2 2 3 3

||

| | |P B A P A B P B

P B AP A P A B P B P A B P B P A B P B

∩= =

+ +

( ) ( )( )

( ) ( )( ) ( ) ( ) ( ) ( ) ( )

3 3 33

1 1 2 2 3 3

||

| | |P B A P A B P B

P B AP A P A B P B P A B P B P A B P B

∩= =

+ +

Generally,

( ) ( )( )

( ) ( )

( ) ( )3

1

||

|

i i ii

i ii

P B A P A B P BP B A

P A P A B P B=

∩= =

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117

Conditional Probability and Bayes Theorem

Exercise 8.4 Page 226

1. a) 67

120 b)

2453

2. ( ) 0.2 0.75| 0.4050.2 0.75 0.2 0.5 0.6 0.2

P engeneer managerial ×= =

× + × + ×

3. ( ) 0.9 0.02| 0.1570.1 0.97 0.9 0.02

P No accident Triggered alarm ×= =

× + ×

End of Unit Assessment Page 228

1. 0.15 2. 0.13 3. 0.56

4. 1

169 5.

15128

6. 7291000

7. 0.37 8. 1021

9. a) 0.34 b) 0.714 c) 0.0833

10. a) 0.43 b) 0.1166 c) 0.8966

11. a) 0.0001 b) 0.0081

12. a) 0.384 b) 0.512

13. 0.1083

14. a) 0.5514 b) 0.2941

15. 313

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118

References

[1] A. J. Sadler, D. W. S. Thorning: Understanding Pure Mathematics, Oxford University Press 1987.

[2] Arthur Adam Freddy Goossens: Francis Lousberg. Mathématisons 65. DeBoeck,3e edition 1991.

[3] David Rayner, Higher GCSE Mathematics, Oxford University Press 2000[4] Direction des Progammes de l’Enseignement Secondaire. Géometrie de l’Espace

1er Fascule. Kigali, October 1988[5] Direction des Progammes de l’Enseignement Secondaire. Géometrie de l’Espace

2ème Fascule. Kigali, October 1988 [6] Frank Ebos, Dennis Hamaguchi, Barbana Morrison & John Klassen,

Mathematics Principles & Process, Nelson Canada A Division of International Thomson Limited 1990

[7] George B. Thomas, Maurice D. Weir & Joel R. Hass, Thomas’ Calculus Twelfth Edition, Pearson Education, Inc. 2010

[8] Geoff Mannall & Michael Kenwood, Pure Mathematics 2, Heinemann Educational Publishers 1995

[9] H.K. DASS... Engineering Mathematics. New Delhi, S. CHAND&COMPANY LTD, thirteenth revised edition 2007.

[10] Hubert Carnec, Genevieve Haye, Monique Nouet, ReneSeroux, Jacqueline Venard. Mathématiques TS Enseignement obligatoire. Bordas Paris 1994.

[11] James T. McClave, P.George Benson. Statistics for Business and Economics. USA, Dellen Publishing Company, a division of Macmillan, Inc 1988.

[12] J CRAWSHAW, J CHAMBERS: A concise course in A-Level statistics with worked examples, Stanley Thornes (Publishers) LTD, 1984.

[13] Jean Paul Beltramonde, VincentBrun, ClaudeFelloneau, LydiaMisset, Claude Talamoni. Declic 1re S Mathématiques. Hachette-education, Paris 2005.

[14] JF Talber & HH Heing, Additional Mathematics 6th Edition Pure & Applied, Pearson Education South Asia Pte Ltd 1995

[15] J.K. Backhouse, SPTHouldsworth B.E.D. Copper and P.J.F. Horril. Pure Mathematics 2. Longman, third edition 1985, fifteenth impression 1998.

[16] M.Nelkon, P. Parker. Advanced Level Pysics, Seventh Edition. Heinemann 1995[17] Mukasonga Solange. Mathématiques 12, Analyse Numérique. KIE, Kigali2006.[18] N. PISKOUNOV, Calcul Différential et Integral tom II 9ème édition. Editions

MIR. Moscou, 1980.[19] Paule Faure- Benjamin Bouchon, Mathématiques Terminales F. Editions Nathan,

Paris 1992.[20] Peter Smythe: Mathematics HL & SL with HL options, Revised Edition,

Mathematics Publishing Pty. Limited, 2005. [21] Rwanda Education Board (2015), Subsidiary Mathematics Syllabus S4-S6,

Ministry of Education: Rwanda.[22] Robert A. Adms & Christopher Essex, Calculus A complete course Seventh

Edition, Pearson Canada Inc., Toronto, Ontario 2010[23] Seymour Lipschutz. Schaum’s outline of Theory and Problems of linear algebra.

McGraw-Hill 1968.[24] Shampiyona Aimable : Mathématiques 6. Kigali, Juin 2005.[25] Tom Duncan, Advanced Physics, Fourth edition. John Murray (Publishers) Ltd,

London 1998[26] Yves Noirot, Jean–Paul Parisot, Nathalie Brouillet. Cours de Physique

Mathématiques pour la Physique. Paris, DUNOD, 1997.