And at least over this interval, it seems it's positive from here to here. So it's positive. This graph is positive when the slope of the tangent line here is positive, and this graph is negative when the slope of the tangent line here is negative. Now one thing that might be causing some unease to immediately say that this last graph is the derivative of the first one is we're not used to situations where the derivative has more extreme points, more minima and maxima, than the original function. But in this case, it could just be because we don't see the entire original function. So for example, if this last graph is indeed the derivative of this first graph, then what we see is our derivative is our graph, our derivative is negative right over here, but then right around here, it starts becoming less negative. So if that point corresponds to roughly right over there, then over here, our slope will become less and less and less negative.