Question

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

Answer 1

`5hati + 5hatj - 5hatk`

Explanation:

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`