And then we're multiplying that times the derivative of sine of x with respect to x. And this is where it might start making a little bit of intuition. You can't really treat these differentials, this d whatever, this dx, this d sine of x, as a number. And the notation makes it look like a fraction, because intuitively that's what we're doing. But if you were to treat them like fractions, then you could think about canceling that and that. And once again, this isn't a rigorous thing to do, but it can help with the intuition. And then what you're left with is the derivative of this whole sine of x squared with respect to x.