Well, a line segment has no area. So this thing right over here is going to be equal to zero. Now, you might say, okay, I get that. I see why that could make sense, why that makes intuitive sense. I have, I'm trying to find the area of a rectangle where I know its height, but it has, its width is zero, so that area is going to be zero, is one way to think about it. But Sal, why are you even pointing this out to me? And as we'll see, especially when we do more complex, definite integration problems and solving things, sometimes, sometimes, recognizing this will help you simplify an integral, an integration problem dramatically.