作者mqazz1 (无法显示)
看板Math
标题[线代] symmetric, nonsingular
时间Sun Mar 20 23:52:02 2011
let A and B be n*n symmetric matrices and let C=AB. Is C symmetric?
let E and F be n*n elementary matrices and let C=EF. Is C nonsingular?
这两题我直觉都是true
因为我看过这样的题目
可是应该怎麽解释呢?
谢谢
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1F：→ THEJOY :证明c_ij=c_ji for i=!j;想想determinant的性质 03/21 00:00
2F：推 nonumber :1楼正解,det(c)=0 if c is singular 03/21 11:43