They gave us g prime and h and g. How do we figure this out? Well here we're going to actually derive something based on the chain rule. And this isn't the type of problem that you'll see a lot of, but it is interesting. So we're going to work through it, and there's a chance that you might see it in your calculus class. So let's start with either one of these expressions up here. So let's start with the expression, well let's start with the, let's do this one over here. So if we have g of h of x is equal to x, h of x is equal to x, so we put that h of x back there, which is by definition true if g and h's are inverses.