Once again, we'll do the quotient rule, but you could also do this using the chain rule. So it's going to be the derivative of the expression on top, which is zero, times the expression on the bottom, which is sine of x, sine of x, minus the expression on top, which is just one, times the derivative of the expression on the bottom, which is cosine of x, all of that over the expression on the bottom squared. Sine squared of x, that's zero, so we get negative cosine of x over sine, over sine squared of x. So that's one way to think about it. Or, if you like, you could view this, the same thing we did over here, this is the same thing as negative cosine of x over sine of x, times one over sine of x. And this is negative cotangent of x, negative cotangent of x, times, let me write it this way, times one over sine of x is cosecant of x. Cosecant, cosecant of x. So whichever one you find more useful.