So let's think about what the second derivative is when we are less than four. And so, actually, let me just try g prime prime of zero, since that'll be easy to evaluate. G prime prime of zero, well, it's just going to be equal to 48. So when we are less than four, our second derivative, g prime, the second derivative is greater than zero. So we are actually going to be concave upwards over this interval to the left of four. Now let's think about to the right of four. Two is a different color.