1. The problem statement, all variables and given/known data 2y = cot(x-y) 3. The attempt at a solution 2y' = -csc2 (x-y) . (1-y)(y') Is it correct so far? My book actually has 2y' = -csc^2 (x-y) + y' csc^2(x-y) And I don't understand where that sum comes from. Am I supposed to apply the product rule? Because I tried and it didn't get me to that step the book presents.