It has that slope of the tangent line when it starts, but then the slope decreases. And it's still an increasing function, but the slope is decreasing. And in that case, we would have an overestimate. And this is a situation, so this first situation, slope is increasing, that means W prime prime is positive. The slope is increasing. The second derivative is positive. This means, or this would be a byproduct, or this would cause the second derivative to be negative.