And I color coded it intentionally so we can say that u of x is equal to e to the x and v of x is equal to cosine of x. So v of x is equal to cosine of x. And if u of x is equal to e to the x, we know that the derivative of that with respect to x is still e to the x. That's one of the most magical things in mathematics. One of the things that makes e so special. So u prime of x is still equal to e to the x. And v prime of x, we know is negative sine of x.