1. The problem statement, all variables and given/known data csc(cos^-1 u) 2. Relevant equations Fundamental identities properties 3. The attempt at a solution The book is incredibly vague on how to do this. I tried multiplying csc by (cosθ/cosθ) to get cotθ*secθ. I'm not sure if this is the right thing to do, or what to do afterward if it is.