(a-b)X(a+b)=2(aXb), where a and b are vectors.
What have you tried so far?
I would start with the definition of cross multiplication.
I tried to set a=<x,y,z> and b=<x1,y1,z1> and expand everything...and the left side became a big mess.
Why don't u multiply exactly what u were given...?I mean there are exactly 4 cross products u'd be getting,when doing it.2 of them are 0...
The cross product is distributive. Use that and some of its other properties to get the answer. No need to fiddle with components.
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