已知A为3阶方阵,且 |A |=1/2.则 |（2A）* |=
问题描述：
已知A为3阶方阵,且 |A |=1/2.则 |（2A）* |=
答
知识点:1.(kA)* = k^(n-1)A*2.|kA| = k^n|A|3.|A*| = |A|^(n-1)|(2A)*| = |2^(n-1)A*| = 2^[n(n-1)] |A*| = 2^[n(n-1)] |A|^(n-1)= 2^[n(n-1)] (1/2)^(n-1)= 2^[(n-1)^2]