A record club has found that the marginal profit, P'(x), in cents, is given by P'(x) = -0.0005x +0.35x +56.2x for x 700, where x is the number of members currently enrolled in the club. Approximate the total profit when 420 members are enrolled by 6 computing the sum P' (x) Ax with i=1 Ax = 70. Marginal profit (in cents) P'(x) = -0.0005x +0.35x +56.2x 54,000- 43,200- 32,400- 21,600- 10,800- 0 II IV V 100 200 300 400 500 600 700 Number of members