1. The problem statement, all variables and given/known data The problem is to differentiate the function. y=cos4(x2 + ex) 2. Relevant equations cos(x)'= -sin(x), (xn)'=n*xn-1, (ex)'=ex*x' 3. The attempt at a solution Thought it would be the chain rule. Here's what I came up with: y'=4cos3(-sin(x2 + ex)(2x + ex) Is this right? If not, any suggestions on what I did wrong?