And we also know at 5 we're at 3. So 1, 2, 3. So at 5 we are right over here. So over the interval that we care about, our graph looks something like this. Our graph looks something like this. So that's the interval that we care about. And we're saying that we were looking for a c whose slope is the same as the slope of the secant line, same as the slope of the line between these two points.