So we did the first part. Now use what we just figured out to determine whether your answer in part A is an underestimate or an overestimate of the amount of solid waste that the landfill contains at time 1 fourth. So in part A, we found the slope of the tangent line at time equals 0. And we use that slope to extrapolate out to 3 months, or time equals 1 fourth, 1 fourth of a year. Now, if the function's W's slope over that fourth was exactly the same as the slope of the tangent line, or if that slope did not change, then our extrapolation would be exactly right. If W's slope is increasing over that time, then our estimate would be an underestimate of the correct thing. And if the slope is decreasing over that time, then our estimate would be an overestimate of the actual amount in the landfill.