《国际贸易》芬斯特拉版人大版练习题答案09.pdfVIP

Import Tariffs and Quotas under Imperfect Competition 9 1. Figure 9-1 shows the Home no-trade equilibrium under perfect competition (with the price PC), and under monopoly (with the price PM). In this question, we compare the welfare of Home consumers in these two situations. a. Under perfect competition, with the price PC, label the triangle of consumer surplus and the triangle of producer surplus. Outline the area of total Home surplus (the sum of consumer surplus and producer surplus). Answer: Refer to Figure 9-1: Consumer surplus is the area under the demand curve D and above the market price, and producer surplus is the area above the marginal cost curve MC and below the market price. Under perfect competition, consumer surplus is PCBPD, where PD is the intersection of the demand curve with the vertical axis. Producer surplus is PCBPMC, where PMC is the intersection of the marginal cost curve with the vertical axis. Total surplus is thus represented by the triangle PMCBPD. b. Under monopoly, with the price PM, label the consumer surplus triangle. Answer: Refer to Figure 9-1: Consumer surplus is the triangle PMAPD. c. Producer surplus is the same as the pro?ts earned by the monopolist. To measure this, label the point in Figure 9-1 where the MR curve intersects MC at point B?. For selling the units between zero and QM, marginal costs rise along the MC curve, up to B?. The monopolist earns the difference between the price PM and MC for each unit sold. Label the difference between the price and the MC curve as producer surplus, or pro?ts. Answer: Refer to the following ?gure: Producer surplus is represented by the trapezoid PMAB?PMC. S-79 S-80 Solutions ■ Chapter 9 Import Tariffs and Quotas under Imperfect Competition Price PD PM PC P MC A B B? MR QM QC MC D Quantity d. Outline the area of total Home surplus with a Home monopoly. Answer: Refer to the ?gure from part (c): Total surplus is represented by the trapezoid PDAB?PMC. e. Compare your answer with parts (a)