Step 1 We recall that the derivative of the function y = sin (x) is given by the following. (sin (x ) ) = 1 - x We note that for the given function, f(x) = sin (3x), we will need to combine the formula above with the chain rule as follows, where u = 3x. du (sin (u)) = 1- u2 dx So, our first step is to determine du dx U = 3X du dx Submit Skip (you cannot come back) Need Help? Read It