1. The problem statement, all variables and given/known data Prove [tex]a \times (b \times c) = (a * c)b - (a*b)c[/tex] For orthagonal coordinates, a,b,c 2. Relevant equations Cross Product and Dot Product 3. The attempt at a solution I thought about expanding both sides out and proving they are equal, but I just realized that the left side of the theorem would give me a vector and the right side would give me a scalar. Perhaps I don't understand the theorem perfectly. Can someone explain the notion about this theorem and how I would go about proving it?