f of g of x is equal to, where everywhere you see the x, you replace with the g of x, the principal root of g of x, which is equal to the principal root of, we've defined g of x right over here, 3x squared minus x. So this thing right over here is exactly f of g of x if we define f of x in this way and g of x in this way. Fair enough. So let's apply the chain rule. What is f prime of g of x going to be equal to, the derivative of f with respect to g? Well, what's f prime of x? f prime of x is equal to, this is the same thing as x to the 1 half power, so we can just apply the power rule.