So instead of it being three x squared, it is three cosine of x squared. And then the chain rule says, if we want to finally get the derivative with respect to x, we then take the derivative of cosine of x with respect to x. Now that's a big mouthful, but we are at the home stretch. We've now figured out the derivative. It's going to be this times this. So let's see, that's going to be negative three, negative three times sine of x times cosine squared of x. And I know that was kind of a long way of saying it.