So if we were to imagine going into it, we have a negative slope. Right at that point, we have a 0 slope. And then we have a positive slope. So the function begins increasing. That's why we say we have a minimum point right over there. So what I did right over here is to try to conceptualize what the function itself could look like given the derivative, in this case, switching from a positive derivative to a negative derivative across that critical point or going from a negative derivative to a positive derivative. That's why this is a criteria for a maximum point.