已知A=(x1,x2,x3),其中x1,x2,x3为三维列向量,且|A|=4,求|B|=|x1,3x1加2x2,2x3)|

问题描述:

已知A=(x1,x2,x3),其中x1,x2,x3为三维列向量,且|A|=4,求|B|=|x1,3x1加2x2,2x3)|

|B| = |x1,3x1+2x2,2x3|
= |x1,2x2,2x3|
= 4|x1,x2,x3|
= 4|A|
= 16.= |x1,2x2, 2x3|= 4|x1,x2, x3|怎么得到的呢谢谢|B| = |x1,3x1+2x2, 2x3|c2-3c1= |x1,2x2, 2x3|2,3列提出2= 4|x1,x2, x3|= 4|A|= 16.