Hi,

I am trying to solve the following problem:

1. Find the projection of on . Hence resolve into two vectors, one parallel to and the other perpendicular to .

I can solve the the first part, just by using the projection formula =

But how do I get it perpendicular to ? I know that if the dot product of two vectors = 0, then they are perpendicular. So:

projection dot ??? = 0. How do I calculate what to dot it with?