在长期均衡点，完全竞争市场中每个厂商的利润都为零。因而，当价格下降时，所有这些厂商只能获得正常利润。（)

假设某一特殊行业的信息如下:Q^D=6500-100P市场需求Q^S=1200P市场供给C（q)=722+q卐

假设某一特殊行业的信息如下:

Q^D=6500-100P市场需求

Q^S=1200P市场供给

C(q)=722+q²/200厂商总成本

MC(q)=2q/200

厂商边际成本

假定所有厂商完全同质，而且市场是完全竞争的。

(1)计算均衡价格、均衡产量、厂商供给产量和每家厂商的利润。

(2)在长期将有厂商进入还是退出市场？试解释。进入或退出将会对市场产生何种影响？

(3)在长期，每家企业销售其产品的最低价格为多少？利润是正的、负的还是为零？解释你的结论。

(4)在短期，每家企业销售其产品的最低价格为多少？利润是正的、负的还是为零？解释你的结论。

Suppose you are give the following information about a particular industry:

Q^D=6500-100P Market demand

Q^S=1200P Market supply

C(q)=722+q²/200 Firm total cost function

MC(q)=2q/200 Firm marginal cost function

Assume that all firms are identical and that the market is characterized by pure competition.

a. Find the equilibrium price, the equilibrium quantity, the output supplied by the firm, and the profit of each firm.

b. Would you expect to see entry into or exit from the industry in the long run？ Explain. What effect will entry or exit have on market equilibrium？

e. What is the lowest price at which each firm would sell its output in the long run？ Is profit positive, negative, or zero at this price？ Explain.

d. What is the lowest price at which each firm would sell its output in the short run？ Is profit positive, negative, or zero at this price？ Explain.

A.垄断竞争市场上每个企业都是价格制定者

B.垄断竞争市场上产品不具差异

C.垄断竞争厂商的需求曲线弹性小于完全竞争厂商的需求曲线

D.垄断竞争厂商短期可能获得正经济利润也可能获得负经济利润

E.垄断竞争厂商长期的经济利润为零

A.完全竟争市场均衡时提供更少的产量、更便的价格

B.完全竟争市场均衡时提供更少的产量、更高的价格

C.完全垄断市场均衡时提供更少的产量、更低的价格

D.完全堃断市场均衡时提供更少的产量、更高的价格

A.在完全竞争的市场中，在成本不变的条件下，行业长期供给曲线是一条水平线

B.在完全竞争的市场中，在成本递增的条件下，行业长期供给曲线向右上方倾斜

C.在完全竞争的市场中，在成本递减的条件下，行业长期供给曲线向右下方倾斜

D.垄断市场的长期供给曲线和完全竞争市场相同

E.垄断竞争市场的长期供给曲线和完全竞争市场相同

A.市场中存在大量厂商

B.销售的产品同质化

C.没有市场进入壁垒

D.以上均正确

此题为判断题(对，错)。

A.MR=MC

B.MR=SMC=LMC

C.MR=SMC=LMC=SAC

D.MR=SMC=LMC=SAC=LAC

下表显示了一个以常数边际成本10美元生产的垄断者面临的需求曲线。（1)计算该厂商的边际收益曲线

下表显示了一个以常数边际成本10美元生产的垄断者面临的需求曲线。

(1)计算该厂商的边际收益曲线。

(2)该厂商的利润最大化产量和价格是多少？该厂商的利润为多少？

(3)在一竞争性行业中均衡价格和数量各为多少？

(4)如果该垄断者被迫以完全竞争的均衡价格生产，社会得益是什么？结果是谁获益谁受损？

The following table shows the demand curve facing a monopolist who produces at a constant marginal cost of $ 10.

a. Calculate the firm' s marginal revenue curve.

b. What are the firm's profit - maximizing output and price？ What is its profit？

c. What would the equilibrium price and quantity be in a competitive industry？

d. What would the social gain be if this monopolist were forced to produce and price at the competitive equilibrium？ Who would gain and lose as a result？