So let's say I have, I'll keep it pretty general right now. Let's say I have a curve. I'll make it a familiar looking curve. Let's say it's the curve y is equal to x squared, which looks something like that. And I want to find the slope. Let's say I want to find the slope at some point. And actually, before even talking about it, let's even think about what it means to find the slope of a curve.