Here, f(x) is measured in kilograms per 4,000 square meters, and x is measured in hundreds of aphids per bean stem. By computing the slopes of the respective tangent lines, estimate the rate of change of the crop yield with respect to the density of aphids when that density is 200 aphids per bean stem and when it is 800 aphids per bean stem. 200 aphids per bean stem 1 kg per 4,000 m2 per aphid per bean stem 800 aphids per bean stem 2 kg per 4,000 m2 per aphid per bean stem