1. The problem statement, all variables and given/known data partial derivative (d/dx) sin(x)cos(x) 2. Relevant equations Partial Derivatives, product rule 3. The attempt at a solution sin(2x) = 2 sin x cos x, therefore y=sin(2x)/2 so y'=cos(2x)*(2/2) = cos (2x)? Is this correct? Is there an easier way of directly finding the derivative without using substitution?