Find the derivative of the function. f(x) = sin (7x) Step 1 We recall that the derivative of the function y = sin(x) is given by the following. 1 (sin(x)) = dx 1-x2 We note that for the given function, f(x) = sin (7x), we will need to combine the formula above with the chain rule as follows, where u = 7x. 1 du (sin (sin(u)) = dx 1-u dx So, our first step is to determine du u = 7x du dx