prod_vect_mixte (1)
TRANSCRIPT
-
8/18/2019 prod_vect_mixte (1)
1/16
i j
B = ( i, j, k) B = ( i, j, − k)
B
(u, v, w)
( i, j) i j
-
8/18/2019 prod_vect_mixte (1)
2/16
( i, j, k)
i j k
( j, k, i) ( k, i, j)
i, j, k
( i, j, k)
v = x i + y j + z k ⇔ v =
x
y
z
u + v =
a
b
c
+
a
b
c
=
a + a
b + b
c + c
λu = λ
a
b
c
=
λa
λb
λc
u.v = aa + bb + cc
||u|| =√
u2 =
a2 + b2 + c2
u2
E ( i,
j,
k)
E
∧
i ∧ j = k j ∧ k = i k ∧ i = j
-
8/18/2019 prod_vect_mixte (1)
3/16
∀(u, v) ∈ E 2, u ∧ v = −v ∧ u
u ∧ (v + w) = u ∧ v + u ∧ w
(u + v) ∧ w = u ∧ w + v ∧ w
(λu) ∧ v = λ(u ∧ v)
∀u ∈ E, u ∧ u = 0
u =
x
y
z
v =
x
y
z
u ∧ v = (x i + y j + z k) ∧ (x i + y j + z k)= xy i ∧ j + xz i ∧ k + yx j ∧ i + yz j ∧ k + zx k ∧ i + zy k ∧ j= xy k − xz j − yx k + yz i + zx j − zy i= (yz − zy ) i + (zx − xz) j + (xy − yx) k
u ∧ v =
yz − yzzx − zxxy − xy
u ∧ v u v
u.(u ∧ v) = x(yz
− y
z) + y(zx
− z
x) + z(xy
− x
y)= xyz − xyz + xyz − xyz + xyz − xyz = 0
v.(u ∧ v) = 0
-
8/18/2019 prod_vect_mixte (1)
4/16
u ∧ v
||u ∧ v||2
= (yz
− y
z)2
+ (zx
− z
x)2
+ (xy
− x
y)2
( u.v)2
||u ∧ v||2 + (u.v)2 = ||u||2.||v||2
u.v = ||u||.||v|| cos (u, v) ||u ∧ v|| = ||u||.||v|| sin (u, v)
π
u∧v
(u, v, u ∧ v) ( i, j, k) k = i ∧ j
(u, v) w = u∧v (u, v, w)
|| w|| = ||u||.||v|| sin (u, v)
|| w
|| = airedu parallélog ramme construit sur u et v
||u ∧ v|| = ||u||.||v||. sin (u, v) = 0 ⇔ ||u|| = 0 ou ||v|| =0 ou sin (u, v) = 0
u = 0 ou v = 0 ou (u, v) = 0 ou π
0 = 0.u
-
8/18/2019 prod_vect_mixte (1)
5/16
P (A, u, v). n = u ∧ v
−−→AM .n = 0
−−→AM .(u ∧ v) = 0
det(−−→AM , u, v) = 0
D (A, u) M H
−−→AM ∧ u = (−−→AH + −−→HM ) ∧ u = −−→HM ∧ u
−−→AH u
−−→HM
u
||−−→AM ∧ u|| = H M.||u|| M D
d(M, D) = ||−−→AM ∧ u||
||u||
∆ = (A, u) R
||−−→AM ∧ u|| = R||u||
||−−→AM ∧ u||2 = R2||u||2
A(1, 0, −2) u =
2
30
−−→AM ∧ u =
x − 1y
z + 2
∧
230
=
−3(z + 2)2(z + 2)
3(x − 1) − 2y
∆
13(z + 2)2 + (3x − 2y − 3)2 = 52
-
8/18/2019 prod_vect_mixte (1)
6/16
9x2 + 4y2 + 13z2
−18x + 12y + 52z
−12xy + 9 = 0
∆ = (A, u) A θ
M
d(M, ∆)
d(M, A) = sin θ
||−−→AM ∧ u||2 = sin2 θ||u||2.AM 2
-
8/18/2019 prod_vect_mixte (1)
7/16
A(2, 0,−
1) u =
1
−1
0
θ = π6
−−→AM ∧ u =
x − 2y
z + 1
∧
1−10
=
z + 1z + 1
−x + 2 − y
2(z + 1)2 + (x + y − 2)2 = 12
[(x − 2)2 + y2 + (z + 1)2]
x2 + y2 + 3z2 − 4x − 8y + 6z + 4xy + 7 = 0
(x ,y ,z) ∈ [−3, 7] × [−5, 5] ×[−6, 4]
u, v, w
(u, v, w) = u.(v ∧ w)
||u||.||v ∧ w|| cos (u, v ∧ w)
-
8/18/2019 prod_vect_mixte (1)
8/16
u, v, w v w
h = ||u|| cos
(u, v ∧ w)
u = λv + µ w u.(v ∧ w)
||u.(v ∧ w)|| = ||u||.||v||.|| w|| sin (v, w)| cos (u, v ∧ w) = 0
u = 0 ou v = 0 ou w = 0 ou u colinéaire à v ou h = 0
u.(v ∧ w) = 0 ⇔ u, v et w coplanaires
u =
x
y
z
, v =
x
y
z
w =
x”
y”z”
u.(v ∧ w) = xy z” + yz x” + zxy” − zy x” − zy”x − z”yx
x x x” x x
y y y” y y
z z z” z z
-
8/18/2019 prod_vect_mixte (1)
9/16
v.(u ∧ w) = −u.(v ∧ w)u.( w ∧ v) = −u.(v ∧ w) w.(v ∧ u) = −u.(v ∧ w)
u.(v ∧ w) = v.( w ∧ u) = w.(u ∧ v)
v.( w
∧u) =
− w.(v
∧u) = +u.(v
∧ w)
f : E → R u f (u)
∀(λ, µ) ∈R2, ∀(u, v) ∈ E , f (λu + µv) = λf (u) + µf (v) u, v, λ
f (u + v) = f (u) + f (v)
f (λ u) = λf (u)
f : E × E → R (u, v) f (u, v),
∀(λ, µ) ∈ R2, ∀(u, v, w) ∈ E 3, f (λu + µv, w) = λf (u, w) + µf (v, w)∀(λ, µ) ∈ R2, ∀(u, v, w) ∈ E 3, f (u, λv + µ w) = λf (u, v) + µf ( u, w)
f : E × E × E → R (u, v, w) f (u, v, w)
∀(λ, µ) ∈ R, ∀( u, v, w, x), f (λu + µv, w, x) = λf (u, w, x) + µf (v, w, x)
∀(λ, µ)
∈ R,
∀( u, v, w, x), f (u, λv + µ w, x) = λf (u, v, x) + µf (u, w, x)
∀(λ, µ) ∈ R, ∀( u, v, w, x), f (u, v, λ w + µx) = λ(u, v, w) + µf (u, v, x)
f (v, u, w) = −f (u, v, w)f (u, w, v) = −f (u, v, w)f ( w, v, u) = −f (u, v, w)
-
8/18/2019 prod_vect_mixte (1)
10/16
det(u, v) = 0 ⇔ u et v colinéaires
∃λ ∈ R, u = λv ou v = λu u v
∀(λ, µ) ∈ R2, (λu + µv = 0) ⇒ (λ = µ = 0)
u.(v∧
w) = 0 ⇔
u, v et w coplanaires
∃(λ, µ) ∈ R2, u = λv + µ w ou v = λu + µ w ou w = λu + µv u, v w
∀(λ ,µ,ν ) ∈ R3, (λu + µv + ν w = 0) ⇒ (λ = µ = ν = 0)
det(u, v, w) = u.(v ∧ w)
u, v, w sont coplanaires ⇔ det(u, v, w) = 0
u, v et w sontliés ⇔ det(u, v, w) = 0
u =
x
y
z
, v =
x
y
z
, w =
x”y”z”
det(u, v, w) =
x x x”y y y
z z z”
-
8/18/2019 prod_vect_mixte (1)
11/16
x x
x” x x
y y y” y y
z z z” z z
x x x”y y y”z z z”
= xy z” + yz x” + zxy” − zy x” − yxz” − xzy”
M = (mij) M t =
(m̃ij) m̃ij = mji
M =
a b c
d e f
g h i
→ M t =
a d g
b e h
c f i
det
a b c
d e f
g h i
=
a b c
d e f
g h i
det(M ) = det(M t)
a b c
d e f
g h i
=
a d g
b e h
c f i
-
8/18/2019 prod_vect_mixte (1)
12/16
b a ce d f
h g i
= −
a b cd e f
g h i
a c b
d f e
g i h
= −
a b c
d e f
g h i
c b a
f e d
i h g
= −
a b c
d e f
g h i
d e f a b c
g h i
= −
a b cd e f
g h i
a b c
g h i
d e f
= −
a b c
d e f
g h i
g h i
d e f
a b c
= −
a b c
d e f
g h i
det(u, λu, v) = λdet( u, u, v) = 0
det(u, v, λv) = λdet( u, v, v) = 0
det(u, v, λu) = λdet( u, v, u) = 0
a b c
d e f
g h i
=
b c a
e f d
h i g
=
c a b
f d e
i g h
a b c
d e f
g h i
=
d e f
g h i
a b c
=
g h i
a b c
d e f
det(λu + µv, w, x) = λdet(u, w, x) + µdet(v, w, x)
-
8/18/2019 prod_vect_mixte (1)
13/16
λa + µb c d
λa
+ µb
c
d
λa” + µb” c” d”
= λ
a c d
a
c
d
a” c” d”
+ µ
b c d
b
c
d
b” c” d”
a λb + µc da λb + µc d
a” λb” + µc” d”
= λ
a b d
a b d
a” b” d”
+ µ
a c d
a c d
a” c” d”
a b λc + µda b λc + µd
a” b” λc” + µd”
= λ
a b c
a” b c
a” b” c”
+ µ
a b d
a b d
a” b” d”
det(M ) = det(M t)
λa + µb λa + µb λa” + µb”c c c”
d d d”
= λ
a a a”c c c”
d d d”
+ µ
b b b”c c c”
d d d”
a a a”
λb + µc λb + µc λb” + µc”d d d”
= λ
a a a”b b b”d d d”
+ µ
a a a”c c c”d d d”
a a a”b b b”
λc + µd λc + µd λc” + µd”
= λ
a a a”b b b”c c c”
+ µ
a a a”b b b”d d d”
a b c
d e f g h i
= a
e f
h i− b
d f
g i+ c
d e
g h
a b c
d e f
g h i
= −d
b c
h i
+ e
a c
g i
− f
a b
g h
a b c
d e f
g h i
= g
b c
e f
− h
a c
d f
+ i
a b
d e
a b c
d e f
g h i
= a
e f
h i
−d
b c
h i
+ g
b c
e f
a b c
d e f
g h i
= −b
d f
g i
+ e
a c
g i
− h
a c
d f
a b c
d e f
g h i
= c
d e
g h
− f
a b
g h
+ i
a b
d e
-
8/18/2019 prod_vect_mixte (1)
14/16
M 3(R)
(S )
ax + by + cz = dax + by + cz = d
a”x + b”y + c”z = d”
x A + y B + z C = D
A =
a
a
a”
B ∧ (x A + y B + z C ) = B ∧ D
B ∧ (x A + z C ) = B ∧ D
C
C.[ B ∧ (x A + z C )] = C.( B ∧ D)
x C.( B ∧ A) = C.( B ∧ D)
xdet( C, B, A) = det( C, B, D)
xdet( A, B, C ) = det( D, B, C )
ydet( A, B, C ) = det( A, D, C )
zdet( A, B, C ) = det( A, B, D)
∆det( A, B, C ) =
a b c
a b c
a” b” c”
x = 1
∆
d b c
d b c
d” b” c”
, y =
1
∆
a d c
a d c
a” d” c”
, z =
1
∆
a b d
a b d
a” b” d”
x D y
z
-
8/18/2019 prod_vect_mixte (1)
15/16
M 3(R) (S )
M X = D
M =
a b ca b c
a” b” c”
X =
xy
z
D =
dd
d”
M
M −1M X = M −1D
X = M −1D
M −1M = I =
1 0 00 1 00 0 1
∆ det(M )
x = 1∆
d b c
d b c
d” b” c”
, y = 1
∆
a d c
a d c
a” d” c”
, z = 1
∆
a b d
a b d
a” b” d”
x = 1
∆[(bc” − b”c)d − (bc” − b”c)d + (bc − bc)d”]
y = 1
∆[−(ac” − a”c)d + (ac” − a”c)d − (ac − ac)d”]
z = 1
∆[(ab” − a”b)d − (ab” − a”b)d + (ab − ab)d”]
x
y
z
= 1
∆
bc” − b”c −(bc” − b”c) bc − bc
−(ac”
−a”c) ac”
−a”c
−(ac
−ac)
ab” − a”b −(ab” − a”b) ab − ab
d
d
d”
1
∆
M −1
+ − +− + −+ − +
cof (M ) =
bc” − b”c −(ac” − a”c) ab” − a”b
−(bc” − b”c) ac” − a”c −(ab” − a”b)bc
− b
c −(ac
− a
c) ab
− a
b
cof (M )
cof (M )t =
bc” − b”c −(bc” − b”c) bc − bc−(ac” − a”c) ac” − a”c −(ac − ac)
ab” − a”b −(ab” − a”b) ab − ab
1
∆
-
8/18/2019 prod_vect_mixte (1)
16/16
M =
1 0 −10 2 3
1 −2 −5
det(M ) M
1 0 −10 2 31 −2 −5
= −10 + 0 + 0 + 2 − 0 + 6 = −2
M
cof (M ) =
−4 3 −22 −4 22 −3 2
M −1 = 1−2 −4 2 23 −4 −3
−2 2 2 =
2 −1 −1− 32
2 32
1 −1 −1
M −1