It's also, we can use that with the derivative properties of sums of derivatives or differences of derivatives to take derivatives of polynomials. This right over here is the product rule. If I have an expression that I wanna take the derivative of and I can think of it as the product of two functions, well then the derivative is gonna be the derivative of the first function times the second function plus the first function times the derivative of the second. Once again, if this looks completely unfamiliar to you or you're a little shaky, go watch the videos, do the practice on the power rule or the product rule, or in this case, the quotient rule. And the quotient rule is a little bit more involved and we have practice and videos on that. And I always have mixed feelings about it, because if you don't remember the quotient rule, you can usually, or you can always convert a quotient into a product by expressing this thing at the bottom as f of x, or by expressing this as f of x times g of x to the negative one, so you could take the derivative with a combination of the products and this fourth rule over here, the chain rule. And if any of this is looking unfamiliar again, don't watch this video.