Now this might seem all very abstract and mathy. How do you actually apply it? Well, let's try it with a real example. Let's say we were trying to take the derivative of the square root of 3x squared minus x. So how could we define an f and a g so that this really is the composition of f of x and g of x? Well, we could define f of x as being equal to the square root of x. And if we defined g of x as being equal to 3x squared minus x, then what is f of g of x?