设A=(1,-1,2),B=(2-10113421),则BT•AT=____.

设A=(1,-1,2),B=
(2-10
113
421)
,则BT•AT=____.
【正确答案】:(9 2 -1) 分析:BTAT= (2 1 4 -1 1 2 0 3 1) (1 -1 2) = (9 2 -1)