为了证明答案给错了!呜呜~我做了八遍还是不对~1-12A=113a不等于2,求A的逆矩阵.a05

Question

为了证明答案给错了!呜呜~我做了八遍还是不对~
1 -1 2
A= 【 1 1 3 】 a不等于2,求A的逆矩阵.
a 0 5

Answer 1

|A| = 10-5a.
A11 = 5,A12 = -5+3a,A13 = -a,
A21 = 5,A22 = 5-2a,A23 = -a,
A31 = -5,A32 = -1,A33 = 2.
A^-1 = (1/|A|)A* = [1/(10-5a)]*
5 5 -5
-5+3a 5-2a -1
-a -a 2