设3级方阵A按列分块为A=(A1,A2,A3),且|A|=5,又设B=(A1+2A2,3A1+4A3,5A2),则|B|=_其他解答

设3级方阵A按列分块为A=(A1,A2,A3),且|A|=5,又设B=(A1+2A2,3A1+4A3,5A2),则|B|=

人气：302 ℃　时间：2020-06-13 10:59:31

解答

|B| = |A1+2A2,3A1+4A3,5A2|
c1-(2/5)c3
= |A1,3A1+4A3,5A2|
c2-3c1
= |A1,4A3,5A2|
=-4*5*|A1,A2,A3|
= -100.