And I say critical point as opposed to just a point where the slope is zero, because it's possible that the function is not differentiable there. You could imagine a function that looks like this. And maybe it wouldn't be differentiable there, but that point there still would be the absolute maximum. So what we really just have to do is evaluate g at the different end points of this interval to see how high it gets or how large of a value we get for the g at the end points. And then we have to see if g has any critical points in between, and then evaluate it there to see if that's a candidate for the global maximum. So let's just evaluate g at the different end points. So let's start off, let's evaluate g at negative 4, at kind of the lowest end or the starting point of our interval.