Cross Product proof

MJC684

1. The problem statement, all variables and given/known data

(u X v) X w = u X (v X w) Iff (u X w) X v = 0
2. Relevant equations

(u X v) = -(v X u)

3. The attempt at a solution

I know that I am supposed to prove this by proving P --> Q and Q --> P
I know that if (u X w) X V = 0 then (u X w) is a scalar multiple of v.

How do i deduce Q from P and P from Q?

tiny-tim

Hi MJC684!

What is (u X v) X w - u X (v X w) ?

(use the Einstein summation convention if you know it, otherwise use coordinates)