Our second derivative is 0. If your slope isn't changing, if your slope is constant, if your first derivative is constant, your second derivative is going to be 0. So let's just see what our second derivative is at our initial condition, and then we'll have a pretty good sense of whether we have an overestimate or an underestimate for part A. So let's just figure out what our second derivative is at time 0. It's going to be equal to 1 over 625 times W of 0, which we know, minus 300. Well, W of 0, the amount of waste we have at time 0, they told us in the problem, is 1400 tons. 1400 minus 1300 is 1100.