What I wanna do is take the derivative of both sides of this equation right over here. So let's apply the derivative operator, d dx on the left-hand side, d dx on the right-hand side, and what are we going to get? Well, on the left-hand side, we would apply the chain rule. So this is going to be the derivative of g with respect to f of x, so that's going to be g prime of f of x, g prime of f of x, times the derivative of f of x with respect to x, so times f prime of x, and then that is going to be equal to what? Well, the derivative with respect to x of x, that's just equal to one. And this is where we get our interesting result. All we did so far is we used something we knew about inverse functions, and we used the chain rule to take the derivative of the left-hand side, but if you divide both sides by g prime of f of x, what are you going to get?