Let P(t) denote the profit made by a company when t dollars are invested in advertising. The marginal profit is dP / dt . (a) Explain the meaning of dP/dt in practical terms.
i. The expression dP/dt is the additional profit expected if t more dollars are invested in advertising.
ii. The expression dp /dt is the total profit expected if 1 more dollar is invested in advertising.
iii. The expression dP/ dt is the difference between the expected profit and the actual profit.
iv. The expression dP /dt is the additional profit expected if 1 more dollar is invested in advertising.
v. The expression dP/ dt is the total profit expected if t more dollars are invested in advertising.
(b) If the marginal profit is positive, should you invest more or less money in advertising?