(0 )2 1436587@9BAC9EDGF4HI 7P5QHRFTSVU0DXW6F4H

¡
T AA = (a2 + b2 + c2 ) + (a2 + b2 ) + a2 = 3a2 + 2b2 + c2
A (BC) =
a 0 0
= (A 2 ) + 2b 2 + c 2
(BC) A =
b a 0
c b a
0 0 0
1 0 0
0 1 0
0 0 0
1 0 0
0 1 0
a 0 0
b a 0
c b a
A (BC) = (BC) A
=
=
0 0 0
a 0 0
b a 0
0 0 0
a 0 0
b a 0
¡ A BC
A B C n A B ¨ ¡
£¢
(A − In) A−1C + B (AB) −1 C = AA−1C − In A−1C + B (AB) −1 C
= InC − A −1 C + B (B −1 A −1 ) C
= C − A −1 C + (BB −1 ) A −1 C
= C − A −1 C + In A −1 C
= C − A −1 C + A −1 C = C
¢ Aα £¢ ¢
¢
1
Aα = 1
−1
−1
−α
1
−1
−α
α + 1
r (Aα) =
−−−−→
ℓ3 + ℓ1
Aα
1 −1 −1
1 −α −α
0 0 α
−−−−→
ℓ2 − ℓ1
2 ¢¡ α = 0 £¥¤ α = 1,
¡
3 ¢¡ α = 0 ¡ α = 1.
1 −1 −1
0 1 − α 1 − α
0 0 α
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