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XA = AX = E,
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AX = E Þ , i=(1,n), j=(1,n),
eij = 0, i ¹ j,
eij = 1, i = j.
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ji - ji .
. = , -1.
det A = 4 - 6 = -2.
M11=4; M12= 3; M21= 2; M22=1
x11= -2; x12= 1; x21= 3/2; x22= -1/2
, -1= .
:
1) (A-1)-1 = A;
2) (AB)-1 = B-1A-1
3) (AT)-1 = (A-1)T.
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2 = = = ; A3 = = .
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= -1
= -1(6 4) 1(9 1) + 2(12 2) = -2 8 + 20 = 10.
= = 2(0 2) 1(0 6) = 2.
= = 2(-4) 3(-6) = -8 + 18 = 10.
: -10 + 6 40 = -44.