So this is the point x f of x. And notice, this top, the numerator right here, this is just our change in the value of our function. Or you could view that as a change in the vertical axis. So that would give you this distance right over here. That's what we're doing up here in the numerator. And then in the denominator, we're finding the change in our horizontal values, horizontal coordinates. Let me do that in a different color.