And that makes sense, because if our second derivative goes from being negative to positive, that means our first derivative goes from being decreasing to increasing, which means the slope of our tangent line of our function goes from decreasing to increasing. We've seen that over and over, decreasing to increasing right over here. Now it's important to realize the second derivative doesn't need to just touch the x-axis. It needs to cross it. So you might say, well, what about this point right over here, two comma zero? The second derivative touches the x-axis there, but it doesn't cross it. So we never go from our derivative increasing to our derivative decreasing.