It's the derivative of f of the outer function with respect to the inner function. So let me write it. It is equal to 1 half times g of x to the negative 1 half times 3x squared minus x. This is exactly this, based on how we've defined f of x and how we've defined g of x. Conceptually, if you're just looking at this, the derivative of the outer thing, you're taking something to the 1 half power. So the derivative of that whole thing with respect to your something is going to be 1 half times that something to the negative 1 half power. That's essentially what we're saying.