cross product?

Question

let k be a scalar. Use the definition of the cross product to explain why ka x b= a x kb = k (a+b) .
this is where a and b are vectors.

Answer 1

I don't think you stated the problem correctly. By definition the result of a cross product is a vector perpendicular to the two vectors in the cross product. a+b is clearly not perpendicular to both a and b

a"dot"(a+b) = a^2 + a "dot" b <> 0 unless a = 0
b "dot" (a +b) = a "dot" b + b^2 <>0 unless b = 0

Answer 2

That's wrong dude!!

a x kb = k (a+b) it's not true...

Answer 3

You've lost me.