So if we would take the derivative with respect to x of the first expression in terms of x. So this is, we could call this u of x u of x times another expression that involves x. So u times v of x. This is going to be equal to, and I'm color coding it so we can really keep track of things. This is going to be equal to the derivative of the first expression. So I could write that as u prime of x times just the second expression, not the derivative of it, just the second expression. So times v of x. V of x.