Suppose the dollar cost of producing x video cameras is C(x) = 500x − 0.003x² + 10−8x³.
(a) Estimate the marginal cost at production level x = 5000 and compare it with the actual cost C(5001) − C(5000).
(b) Compare the marginal cost at x = 5000 with the average cost per camera, defined as C(x)/x.