We're also not continuous at x is equal to one. And then the last situation where we are not going to be differentiable is where we have a sharp turn, or you could kind of view it as a sharp point on our graph. And I see a sharp point right over there. Notice, as we approach from the left-hand side, the slope looks like a constant, I don't know, it looks like a positive 3 1⁄2. Well, as we go to the right side of that, it looks like our slope turns negative. And so if you were to try to find the limit of the slope as we approach from either side, which is essentially what you're trying to do when you try to find the derivative, well, it's not going to be defined because it's different on either side. So f is also not differentiable at the x value that gives us that little sharp point right over there.