Question

@线性代数大神：这道题这样做为什么错了?第5题

Answer 1

2(AB)* =2(AB)^-1 *|AB|

=2(AB)^-1*|A||B|

=2*2*4*(AB)^-1

=16(AB)^-1

|(AB)^-1 -2(AB)*|

=|-15(AB)^-1|

=(-15)^n *|(AB)^-1|

=(-15)^n *|AB|^-1

=(-15)^n*(|A||B|)^-1

=(-15)^n / 8