Question

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|

Answer 1

|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.