But what is the slope of that tangent line? What is the slope of that tangent line? Which is the same as the slope of the curve right at that point. So to do it, I'm going to actually do this exact technique that we did before. And then we'll generalize it so you don't have to do it every time for a particular number. So let's take some other point here. Let's call this 3 plus delta x. I'm changing the notation because in some books you'll see an h, some books you'll see a delta x.