高代题,设四阶方阵A=（2A1,3A2,4A3,A4）,B=(A1,A2,A3,A5)其中Ai均为4×1矩阵,且detA=4,detB=1,试
问题描述：
高代题,设四阶方阵A=（2A1,3A2,4A3,A4）,B=(A1,A2,A3,A5)其中Ai均为4×1矩阵,且detA=4,detB=1,试
detB=1,试求det（A－B)
答
det（A－B)
= det(A1,2A2,3A3,A4-A5)
= det(A1,2A2,3A3,A4) + det(A1,2A2,3A3,-A5)
= 2*3det(A1,A2,A3,A4) - 2*3det(A1,A2,A3,A5)
= (1/4)*(2A1,3A2,4A3,A4) -6 det(A1,A2,A3,A5)
= (1/4)detA - 6det(B)
= (1/4)*4 - 6*1
= -5.我也是这样做的，可是答案不是啊答案错了这正常 ^_^