And then the other one, you'll take the derivative of the other one but not the first one. So derivative of u times v is u prime times v plus u times v prime. Now when you just look at it like that, it seems a little bit abstract and that might even be a little confusing but that's why we have a tangible example here. 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.