And so, and you can see when it looks something like that, the slope is constantly decreasing. So if you have an interval where the slope is decreasing and you know the point where the slope is exactly zero, which is where x is equal to 3.528, it must be a maximum. It must be a maximum. So we actually do take on a maximum value when x is 3.528. On the other side, we see that over here we are concave upwards, concave upwards. Concave upwards, the graph will look something like this over here. And if the slope is zero where the graph looks like that, we see that that is a local minimum.