6 A record club has found that the marginal profit, P'(x), in cents, is given by P'(x) = -0.0008x3 + 0.34x + 57.8x for x 400, where x is the number of members currently enrolled in the club. Approximate the total profit when 240 members are enrolled by computing the sum P' (x)) Ax with Ax=40. i=1 The total profit when 240 members are enrolled is approximately $ (Round to the nearest cent as needed.) 28,000- 22,400- 16,800- (x)=-0.0008x3 +0.34x+57.8x Marginal profit (in cents) 11,200- 5,600- NV VI 100 200 300 400 Number of members