Question

What is the cross product of `[9,4,-1]` and `[-1, -1, 2]`?

Answer 1

`A X B=7i-17j-5k`

Explanation:

`A=[a_i,a_j,a_k]`
`B=[b_i,b_j,b_k]`
`A X B=i(a_j*b_k-a_k*b_j)-j(a_i*b_k-a_k*b_i)+k(a_i*b_j-a_j*b_i)`
`thus;`
`A=[9,4,-1]`
`B=[-1,-1,2]`
`A X B=i(4*2-(-1*-1))-j(9*2-(-1*-1))+k(-1*9-4*-1)`
`A X B=i(8-1)-j(18-1)+k(-9+4)`
`A X B=7i-17j-5k`