It's going to be equal to the derivative of the numerator function, u prime of x, times the denominator function, v of x, minus the numerator function, u of x, do that in that blue color, u of x times the derivative of the denominator function, times v prime of x. And this already looks very similar to the product rule. If this was u of x times v of x, then this is what we would get when we took the derivative if this was a plus sign, but this is here a minus sign. But we're not done yet. We would then divide by the denominator function squared, v of x squared. So let's actually apply this idea. So let's say that we have f of x is equal to x squared over cosine of x.