And here we just apply the chain rule. It's going to be the derivative of sine of y with respect to y, which is going to be cosine of y times the derivative of y with respect to x. So times dy dx. Times dy dx. And the right-hand side, what's the derivative of x with respect to x? Well, that's obviously just going to be equal to 1. And so we could solve for dy dx, divide both sides by cosine of y, and we get the derivative of y with respect to x is equal to 1 over cosine of y.