What is the cross product of $[3,-1,2]$ and $[1,-2,-1]$ ?

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Answer 1 · 2016-10-02T18:45:34

$5hati + 5hatj - 5hatk$

I use a 5 column matrix to compute the cross product:
|i....j.....k|i....j|
|3 -1....2|3 -1|
|1. -2. -1|1. -2|

$= hati{(-1)(-1) - (2)(-2)} + hatj{(2)(1) - (3)(-1)} + hatk{(3)(-2)-(-1)(1)}$

$= 5hati + 5hatj - 5hatk$

What is the cross product of [3,-1,2][3,-1,2] and [1,-2,-1] [1,-2,-1] ?