已知A,B均为n阶矩阵,设A为阶数大于2的可逆方阵,则(A*)^-1=(A^-1)*,怎么证明
问题描述:
已知A,B均为n阶矩阵,设A为阶数大于2的可逆方阵,则(A*)^-1=(A^-1)*,怎么证明
答
(A*)^-1 = (|A| A^-1)^-1 = A/|A|
(A^-1)*= (1/|A| A* )*=(1/|A|)* ( A* )*
(1/|A|)* = (1/|A|)^n-1 ( A* )*= A (|A|)^n-2
(1/|A|)* ( A* )* = (1/|A|)^n-1 乘以A (|A|)^n-2 = A/|A|
两者相等.