.
II
. ..
2009
: . .., - ..
: . .. , -- ..
.. . : II / ... : . .., 2008. 30 . | |
II . . . . |
ã .., 2009
ã . .., 2009
.
4
2. . 7
3. . 11
4. . 12
5. . 15
1. . 27
2. . 28
. 29
. 30
1.
. V , A : V V , . l A, u,
A u = l u. (1)
u A, l.
, V 3, . . , V 2 ( ). B = { i, j, k } V 3. A A. (x, y, z) . (1) :
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= l.
,
(a 11 - l) x + a 12 y + a 13 z = 0,
a 21 x + (a 22 - l) y + a 23 z = 0, (2)
a 31 x + a 32 y + (a 33 - l) z = 0.
, , :
det = 0. (3)
, l, A. l1, l2, l3 .
l1 (2) (x 1, y 1, z 1). (x 1, y 1, z 1) A, l1. , l2 l3, (x 2, y 2, z 2) (x 3, y 3, z 3). , .. k (xi, yi, zi) (2) l = l i k ¹0. l1, l2, l3.
(3) l1, l2 l3 ( : l3 = ). A (x 1, y 1, z 1).
, a, b, c
x 3 + px 2 + qx + r = 0,
(x a)(x b)(x c) = 0.
a b,
(x a)(x b)2 = 0 ( (x a)2(x b) = 0).
, b ( a) 2. a,
(x a)3 = 0.
, a 3.
(3) . , , l1 1, l2 2. l2 (2) , 2. A . l2 (2) , 1. , . , , A, l2. , A
(x 1, y 1, z 1),
= k + l = (kx 2 + lx 3, ky 2 + ly 3, kz 2 + lz 3), k, l Î R.
(3) l1. (2) 2, 1 0. , ,
= k + l, k, l Î R,
, (2). , (2) 0, , A : A = l1 E. A .
A A. , , , V 3 , , . , , .
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1. A: V 3 V 3, V 3
A =.
. 1. A l E:
A l E =. (4)
A det(A l E) = 0. ,
(8 l)(l2 3l 4) = 0 .
l1= -8, l2 = 4, l3 = 1.
2. (4) l1= -8:
A + 8 E =.
:
9 y + 3 z = 0,
2 y + 10 z = 0.
y = z = 0. , ? ! - x. (1, 0, 0).
3. (4) l2 = 4 :
A - 4 E =,
. . , x = 0, y = z. (0, 1, 1).
4. l3 = 1 (0, 1, 1).
: l1= -8, (1, 0, 0);
l2 = 4, (0, 1, 1);
l3 = 1, (0, 1, 1).
, , 2.
.
. B: V 3 V 3 A: V 3 V 3, , Î V 3
(A)= (B).
( ). B =A *. A , A * = A.
A A { i, j, k }, A * A T. A T= A. , ( ).
, A , , , . (3) (.. ) , , . 3 A. , V 3, A.
{, , } - V 3, A, l1, l2, l3 .
A = l1
A = l2
A = l3
, {, , } A
A =. (5)
k, l, m k, l, m Î R,
=, =, =.
{, , } .
2. A: V 3 V 3 :
A = 2 j - k
A = 2 i + 3 j - 2 k
A = - i - 2 j.
V 3, A .
. 1. A A { i, j, k } A -l E:
A =, A l E =
( : ; ). det(A l E) , . :
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det(A l E) = -l3 + (tr A)l2 - I2(A)l + det A. (6)
tr A = a 11 + a 22 + a 33 - A (.. ),
I2(A) = + +
A. :
I2(A) = + +
tr A =0+3+0=3, det A = 5,
I2(A) = + + = 9.
-l3 + 3l2 + 9l + 5 = 0 Û l3 - 3l2 - 9l - 5 = 0. (7)
: l1 = 1. l l1:
-
-
-
0
(7) :
(l + 1)(l2 - 4l - 5) = 0.
: l2 = -1, l3 = 5. , :.
2. , 1, (1, 2,-1), l3 = 5.
3. l1 = l2 = -1. : l1 l2 , .
A - (-1) E =,
1, .. , . , 1. , :
x + 2 y - z = 0, (8)
(1, 0, 1), (0, 1, 2). , l1 = l2 = -1,
= k + l = (k, l, k + 2 l), k, l Î R. (9)
, 1, . , . : l1 l2 , . . (1, 0, 1) . (x, y, z) (8), :
(1, 0, 1) (x, y, z) = 0.
, (x, y, z)
x + 2 y - z = 0,
(1, 0, 1) (x, y, z) = 0.
x + z = 0. :
x + 2 y - z = 0,
x + z = 0.
y = - x, z = - x. (1,-1,-1).
, . , :
|| = =, =
|| = =, =
|| = =, =
: ,
,,,
A
A = .
3.
. L . , L f: L ´ L R, (x, y) f (x, y), ; ..
1. f (x + y, z) = f (x, z) + f (y, z); f (x, y + z) = f (x, y) + f (x, z);
2. f (l x, y) =l f (x, y) = f (x, l y), lÎ R.
, f (y, x) = f (x, y) " x, y Î L.
L 3 , B = { e 1, e 2, e 3} . x (x 1, x 2, x 3), y (y 1, y 2, y 3) .
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f (x, y) = f (x 1 e 1 + x 2 e 2 + x 3 e 3, y 1 e 1 + y 2 e 2 + y 3 e 3) = xiyjf (e i, e j).
. aij = f (e i, e j), i, j = 1, 2, 3. , x, y, . .
:
f (x, y) = aijxiyj = a 11 x 1 y 1 + a 12 x 1 y 2 + a 13 x 1 y 3 + a 21 x 2 y 1 + a 22 x 2 y 2 + a 23 x 2 y 3 +
+ a 31 x 3 y 1 + a 32 x 3 y 2 + a 33 x 3 y 3.
, . ,
aji = f (e j, e i)= f (e i, e j) = aij, i, j = 1, 2, 3.
, . :
f (x, y) = a 11 x 1 y 1 + a 22 x 2 y 2 + a 33 x 3 y 3 +
+ a 12(x 1 y 2 + x 2 y 1) + a 13(x 1 y 3 + x 3 y 1) + a 23(x 2 y 3 + x 3 y 2). (10)
:
f (x, y) = a 11 x 1 y 1 + a 22 x 2 y 2 + a 12(x 1 y 2 + x 2 y 1).
. f (x, y) . k: L R, k (x) = f (x, x) . , f (x, y) k (x). .
, , L 3, (10) y = x:
k (x) = a 11 x 12+ a 22 x 22+ a 33 x 32+ 2 a 12 x 1 x 2 + 2 a 13 x 1 x 3 + 2 a 23 x 2 x 3. (11)
V 3, (x, y, z),
k ( ) = a 11 x 2+ a 22 y 2+ a 33 z 2+ 2 a 12 xy + 2 a 13 xz + 2 a 23 yz. (12)
, xy, xz, yz . , a 12 21:
A =.