迈克尔版本微观经济学 第六章 Chapter6_SM
2019年-微观经济学06章-PPT精选文档
中南林业科技大学经济学院 蔡卫中
西方经济学·微观·第6章 2
2.市场结构共有4种教材184页
市场结构 完全竞争 垄断竞争 寡头 垄断
厂商数量 产品性质 很多 产品无差别 较多 产品有差别 几家 有或无差别 一家 产品有特点
典型部门 农产品 轻工业 重工业 公用事业
划分不同市场结构的依据是： 根据市场上竞争和垄断的程度
中南林业科技大学经济学院 蔡卫中
西方经济学·微观·第6章 7
4.完全竞争厂商的收益曲线
P D
E P0
S
dd dd AR=MR=P
Q
AR = MR = P=dd
中南林业科技大学经济学院 蔡卫中
西方经济学·微观·第6章 8
三、利润最大化
1. 数学推导。π表示厂商的利润：π=TR-TC
ma xT(Q R 0)T(Q C 0)
（1）盈利：行业供给小于需求，价格水平比较高。
利润最大化原则：MR=MC
E点为厂商决策点
决定产量OM，价格ON。
P
TR=OMEN
TC=OMKG
N
超额利润GKEN
G
（绿色部分）
P=AR＞SAC，
厂商处于盈利状态。
O
中南林业科技大学经济学院 蔡卫中
SMC SAC
E
K dd
AR=MR=P
M
西方经济学·微观·第6章 14
（3）厂商需求曲线切于SAC最低点。
P=AR=SAC， 厂商的利润恰好为零,处于盈亏平衡状态
P
SMC
SAC
N
E
dd
（AR=MR=P）
OM
Q
中南林业科技大学经济学院 蔡卫中
微观经济学(6)政府政策
18
向买者征税
新均衡： Q = 450 卖者得到的价格： PS = $9.50 PB = $11.00 买者支付的价格： $10.00 P = $11.00 PS = $9.50
B
向买者征收$1.50的税收
P 税 收 S1
两者之差 = $1.50 = 税收
D2 450 500
供给、需求与政府政策
因此，在当前的政府框架中，提高粮价是关键之
策、点睛之笔。
内容提要
价格上限是某种物品或劳务的法定最高价格。租
金控制是一个例子。如果价格上限低于均衡价格， 则需求量大于供给量，会引起短缺
价格下限是某种物品或劳务的法定最低价格。最
低工资是一个例子。如果价格下限高于均衡价格， 则供给量大于需求量，会引起劳动力超额供给， 也就是失业
帮助的人
供给、需求与政府政策
15
税收
政府对许多物品与劳务征税是为了给国防，公立
学校等这类公共项目筹资
政府能向买者或卖者征税
税收可以是物品价格的一个比例或者每售出一单
位物品需支付一定数量的货币 简化起见，我们仅分析后者
供给、需求与政府政策
16
例 3: 皮萨市场
P
没有税收 时的均衡
$10.00
入户的人均粮食消费为78公斤，按占城镇人 口比例20％计，为11541万人。假设粮食价 格每公斤上涨0.2元，那么低收入人群每人 增加粮食消费为15.6元，如果这部分钱全部 由财政来补贴，仅需18亿元，远远低于 1028亿元的种粮补贴。即使财政给所有国 人都补贴，上涨0.2元，也仅需支出200亿元 ，还是要比种粮补贴节约。
案例 1: 供给相对于需求更富有弹性
微观经济学第六章PPT课件
练习
完全竞争市场
1、完全竞争企业所面对的需求曲线同时是 （D）
A.总收益曲线
B.平均收益曲线
C.边际收益曲线 收益曲线
D.平均收益曲线与边际
2、在完全竞争市场中，厂商总收益曲线的斜率 为（ A ）
A.固定不变
B.经常变动
C.1
D.0
完全竞争市场
3、如果某厂商的边际收益大于边际成本，那么为了取得最
完全竞争市场
3.不同类型市场的特点
市场和厂 商的类型
厂商
的数 目
产品差别的程 度
对价格控制 的程度
进出一个行 业的难易程
度
接近哪种 市场情况
完全竞争 很多 完全无差别 没有
很容易
农业
垄断竞争 寡头 垄断
较多 几个 一个
有差别
有差别或无差 别
唯一的产品， 没有接近的替 代品
有一些
比较容易
相当程度 比较困难
在长期中，厂商如何实现MR=LMC的利润最大化 的原则？
厂商对生产要 素的调整方式
对最优生产规模的选择 进入或退出一个行业
完全竞争市场
1.对最优生产规模的选择
P（ MR） = LMC =SMC
P
SMC1
SMC2
P
SAC1 E
LMC B
0
F
G
SAC2 LAC
H
D
D (AR=MR=P)
Q
Q1
Q2
. 长期内，厂商通过对最优生产规模的选择， 获得比短期内更大的利润。
完全竞争市场
三、成本递减行业的长期供给曲线
成本递减行业是指该行业产量的增加会导 致生产要素价格的下降。
P
微光经济学第六章
24
第三节 完全竞争市场的长期均衡
25
完全竞争厂商的长期均衡原则
厂商在长期对生产要素的调整有两类： 对最优的生产规模的选择 进入或退出一个行业
完全竞争长期均衡原则 P=LMC
26
供小于求，市场价格高， 有超额利润，吸引新厂商进 入，价格回落； 供大于求，市场价格低，存 在亏损，部分厂商退出，价 格回升；
第六章 完全竞争市场中的厂商
1
第一节 厂商和市场的类型
2
决定市场竞争程度的因素
第一，卖者和买者的集中程度或数目。
第二，不同卖者之间各自提供的产品的差别程度。
第三，单个厂商对市场价格控制的程度。
第四，厂商进入或退出一个行业的难易程度。
3
市场结构共有4种
市场结构 完全竞争 垄断竞争 寡头垄断 完全垄断
S
AVC
E2 E3
P4 P5
O
E4
E5 Q5 Q 4 Q2 Q1
E4
SMC O Q4 Q3 Q2 Q1 Q
Q
Q3
完全竞争厂商的短期供给曲线是SMC在AVC之上部分
22
1、已知某完全竞争行业中的单个厂商的短期成本函
3 2 数为STC=0.1Q-3Q+10Q+200 。当市场上产品价 格P=100时，求厂商的短期均衡产量和利润。
P
LMC
LAC
N
E
dd
（AR=MR =P）
O
M 进一步分析
Q
27
P 利润最大化原则：P=LMC
LMC
LAC
E点为厂商决策点
N 既无超额利润，也无亏损 O M Q
E d（AR=MR=P）
微观经济学6
Firm
27
© copyrights by 苏莱曼 2004. imfec.
厂商与行业的长期调整及长期均衡
• 行业与厂商的长期均衡 P=MR=SMC=LMC=SAC=LAC
＄
LMC LAC
SMC2 SAC2
P2
E
d2
O
Q2
Q
28
© copyrights by 苏莱曼 2004. imfec.
Firm
微观经济学
Microeconomics
内蒙古财经学院经济学系 内蒙古财经学院经济学系
西方经济学教研室
微观经济学 Microeconomics
第六章
完全竞争市场
第六章 完全竞争市场中价格与产量决定
本章主要内容： （1）厂商实现利润最大化的条件 （2）完全竞争市场的特点、需求曲线和收益曲线 （3）完全竞争市场的短期均衡和短期供给曲线 （4）完全竞争市场的长期均衡和长期供给曲线 （5）生产者剩余的概念及其应用
MC
AC AVC
厂商短期产 品供给曲线
Q
23
© copyrights by 苏莱曼 2004. imfec.
厂商与行业的短期供给曲线
• $ 行业短期产品供给曲线
S1 S2 S3 S=S1+S2+S3
行业短期供给曲线 为行业内各厂商供 给曲线的水平加总
P3
P2 P1
O
2
4 5 6 7 8
10
15
22
3
© copyrights by 苏莱曼 2004. imfec.
第六章 完全竞争市场中价格与产量决定
• • • • • • • 第一节 市场、厂商与行业 第二节 厂商的收益和利润 第三节 完全竞争市场的特点 第四节 完全竞争市场下的短期均衡 第五节 完全竞争市场下的长期均衡 第六节 蛛网模型 问/答
微观经济学第六章
30
3、成本递减行业的长期供给曲线
完全竞争行业的短期供给曲线可以粗略地看成是该行业所有厂商的短期 S曲线的加总。 n
P P2 P1
S
P P2 P1
S Si
i 1
Q O
10 25
单个厂商的供给曲线
q
O
1000
2500
22
整个行业的供给曲线
四、生产者剩余（Producer surplus)
生产者剩余：厂商在提供一定数 量的商品时实际得到的价格（市 场价格）与愿意接受的价格的差 额。 短期内，只要P>AVC，厂商就开 工生产。由于短期内，FC是沉没 成本，一时无法回收的，厂商开 工生产增加1单位产量所增加的成 本是变动成本（也是MC），因此 只要P>MC，厂商就愿意开工。 这时生产一定数量的商品实际得 到的与他愿意接受的（大于边际 成本的部分）的差额就是生产者 剩余。
小麦市场的需求曲线是向下倾斜的一条直线， 当小麦价格上升时其需求量也会下降。但是单 个农场主所面临的需求曲线并不是向下倾斜的： 它是一条水平线。一旦某个农场主试图提高价 格时，则对其销售的小麦需求量马上会降为零， 因为消费者将会转而购买其他农场主所生产的 小麦。但是，在既定的市场价格下，每一个农 场主都可以销售他想销售的任何数量的小麦， 因为任何一个农场主生产的产品数量相对于整 个市场容量都是很小的。
MC E
AC
P0 C
AVC D
O
Q0
16
2、P=AC，厂商收支相抵，获得正常利 润
利润最大化原则为 MR=MC，故E点为厂商 决策点，决定产量OQ， 价格OP， TR=P*Q=OPEQ TC=AC*Q=OPEQ P0 利润 =（P-AC）*Q=0 P MC AC
西方经济学(微观经济学)课后练习答案第六章
西方经济学(微观经济学)课后练习答案第六章1、某完全竞争行业中的单个厂商的短期本钱函数为STC=0.1Q3-2Q2+15Q+10。
试求：〔1〕当市场上产品的价格为P=55时，厂商的短期平衡产量和利润；〔2〕当市场价格下降为多少时，厂商必须停产？〔3〕厂商的短期供应函数。
解答：〔1〕因为STC=0.1Q3-2Q2+15Q+10所以SMC==0.3Q3-4Q+15根据完全竞争厂商实现利润最大化原那么P=SMC，且P=55，于是有：0.3Q2-4Q+15=55整理得：0.3Q2-4Q-40=0解得利润最大化的产量Q*=20〔负值舍去了〕以Q*=20代入利润等式有：=TR-STC=PQ-STC=〔55×20〕-〔0.1×203-2×202+15×20+10〕=1100-310=790即厂商短期平衡的产量Q*=20，利润л=790〔2〕当市场价格下降为P小于平均可变本钱AVC即PAVC 时，厂商必须停产。
而此时的价格P必定小于最小的可变平均本钱AVC。
根据题意，有：AVC==0.1Q2-2Q+15令，即有：解得 Q=10且故Q=10时，AVC〔Q〕达最小值。
以Q=10代入AVC〔Q〕有：最小的可变平均本钱AVC=0.1×102-2×10+15=5于是，当市场价格P5时，厂商必须停产。
〔3〕根据完全厂商短期实现利润最大化原那么P=SMC，有：0.3Q2-4Q+15=p整理得 0.3Q2-4Q+〔15-P〕=0解得根据利润最大化的二阶条件的要求，取解为：考虑到该厂商在短期只有在P>=5才消费，而P＜5时必定会停产，所以，该厂商的短期供应函数Q=f〔P〕为：，P>=5Q=0 P＜52、某完全竞争的本钱不变行业中的单个厂商的长期总本钱函数LTC=Q3-12Q2+40Q。
试求：〔1〕当市场商品价格为P=100时，厂商实现MR=LMC时的产量、平均本钱和利润；〔2〕该行业长期平衡时的价格和单个厂商的产量；〔3〕当市场的需求函数为Q=660-15P时，行业长期平衡时的厂商数量。
微观经济学-Chapter6
微观经济学Chapter61、Ahmed, Boris, Roberto, and Sunil all want to attend a football game. The admission price is $48. Ahmed is willing to pay $59 for the ticket. Boris is willing to pay $39. Roberto is willing to pay $45 and Sunil is willing to pay $55. Based on this information, who will go to the game?A. Boris, Roberto, and SunilB. All four of themC. Ahmed and SunilD. Boris and Roberto--------------------------------------------------------------------------------2、Suppose the price of a hotel room in San Diego averages $200 per night. At that price suppose 30,000 people stay in hotel rooms on an average night in San Diego. If the average level of consumer surplus for each hotel guest equals $24, what is the total consumer surplus per night?A. $480,000B. $600,000C. $720,000D. $528,000--------------------------------------------------------------------------------3、Javier and Pierre each want to buy an ice cream cone. Javier is willing to pay $2.50 and Pierre is willing to pay $4.00. If the ice cream cone costs $2.25, what is the total consumer surplus after Javier and Pierre make their purchases?A. $4.50B. $2.00C. $0.25D. $6.50-----------------------------------------------------------------------------4、Graciela is willing to sell 1 dozen roses for $50, while Giuseppe is willing to sell 1 dozen roses for $60. Carlos is willing to buy 1 dozen roses for $60, while Yuriko is willing to pay $50. If the market price is $52, how many roses are sold and what is the sum total of consumer and producer surplus after the transaction(s)?A. Two dozen roses will be sold, and the total consumer and producer surplus will be $16.B. No roses will be sold, and consequently the total consumer and producer surplus will be $0.C. One dozen roses will be sold, and the total consumer and producer surplus will be $10.D. One dozen roses will be sold, and the total consumer and producer surplus will be $16.--------------------------------------------------------------------------------5、An excise tax imposed on chocolate would create a deadweight loss becauseA. it will discourage new firms from entering the chocolate-making business.B. it will prevent some mutually beneficial trades from occurring.C. it will dampen the profits of chocolate producers.D. it will reduce the demand for chocolate.--------------------------------------------------------------------------------6、In a voluntary exchange,A. both the producer and the consumer can experience a net benefit.B. the amount of consumer surplus will equal the amount of producer surplus.C. if the consumer derives consumer surplus, the supplier will derive no producer surplus.D. if the supplier derives producer surplus, the consumer will derive no consumer surplus.--------------------------------------------------------------------------------7、Suppose at a price of $1.73 per gallon, residents of Tacoma purchase 1 million gallons of gas every week and enjoy a total consumer surplus of $730,000. If gas prices increase to $2.46 per gallon and the demand for gas is perfectly inelastic in Tacoma, residents of Tacoma will end up with a total consumer surplus equal toA. $2,460,000.B. $0.C. $.73 per gallon.D. $730,000.--------------------------------------------------------------------------------8、Which of the following statements is TRUE?A. The amount of deadweight loss resulting from an excise tax will increase as the demand becomes more inelastic.B. An excise tax does not create a deadweight loss if the taxed good is a necessity.C. An excise tax does not create a deadweight loss if the taxed good is a luxury.D. The amount of deadweight loss resulting from an excise tax will increase as the demand becomes more elastic.--------------------------------------------------------------------------------9、The amount of the deadweight loss resulting from an excise tax isA. the difference between the government revenue from an excise tax and the reduction in total surplus resulting from imposition of the tax.B. the difference between the amount of consumer surplus and the amount of producer surplus remaining after imposition of the tax.C. independent of the elasticity of demand for the taxed good.D. the amount of revenue collected from the tax.--------------------------------------------------------------------------------10、Some proponents of an excise tax on cigarettes argue that it will discourage smoking. Others argue that it will collect revenue for the government. Given the economic model of supply and demand, which of the following is true?A. The less elasticity there is in the supply of and demand for cigarettes, the more revenue will be collected from the tax.B. A tax that discourages smoking will not cause a deadweight loss.C. The more the tax discourages smoking, the more revenue it will collect for the government.D. The more elasticity there is in the supply of and demand for cigarettes, the more revenue will be collected from the tax.--------------------------------------------------------------------------------11、Which area on a graph represents producer surplus?A. The area above the supply curve up to a line indicating priceB. The area under the demand curve down to a line indicating priceC. The area between the supply and demand curves to the left of the equilibrium pointD. The area between the supply and demand curves to the right of the equilibrium point--------------------------------------------------------------------------------12、Consumer surplus isA. the amount of revenue collected from an excise tax.B. the difference between the price that consumers are willing to pay for a good and the amount they actually pay.C. the difference between the quantity of a good demanded and the quantity supplied.D. the quantity.Of a good that remains on the market in instances of market failure.--------------------------------------------------------------------------------13、Samia is willing to pay $10 for one bracelet and $5 for a second. Isabella is willing to pay $12 for one bracelet and $2 for a second. If the price is currently $8 per bracelet, what is the total consumer surplus after Samia and Isabella make their purchases?A. $5B. $7C. $6D. $8--------------------------------------------------------------------------------14、Which of the following is NOT a predictable result from imposition of an excise tax?A. The quantity demanded decreases.B. The quantity supplied decreases.C. A deadweight loss results.D. Producer profits increase.--------------------------------------------------------------------------------15、Mario is willing to mow one lawn for $18; he will mow a second for $22, and a third for $28. Assume that the market rate for lawn mowing is $24. How many lawns will Mario mow? What will be his total revenue? What will be his producer surplus?A. Mario will mow two lawns for a total revenue of $48, and his producer surplus will be $2.B. Mario will mow three lawns for a total revenue of $72, and his producer surplus will be $4.C. Mario will mow two lawns for a total revenue of $48, and his producer surplus will be $8.D. Mario will mow three lawns for a total revenue of $72, and his producer surplus will be $2.--------------------------------------------------------------------------------16、Economic theory asserts thatA. the equilibrium market price will maximize consumer surplus and minimize producer surplus.B. both producers and consumers gain from trade.C. all consumers have the same willingness to pay for a good.D. all producers have the same cost of providing a good.--------------------------------------------------------------------------------17、An efficient outcome is one in whichA. no individual seller could be made better off.B. no individual can be made better off without making someone else worse off.C. all consumers who desire the good can afford it at the current price.D. no individual buyer could be made better off.--------------------------------------------------------------------------------18、In 1990 the U.S. government imposed a special sales tax on yachts with a price of at least $100,000. The tax was repealed in 1993 since it generated far less revenue than expected and led to significant job losses in the yacht building industry. The sales tax was unsuccessful becauseA. the supply and the demand for yachts were relatively inelastic.B. the tax rate was too low.C. the supply and the demand for yachts were relatively elastic.D. yachts are luxury goods.--------------------------------------------------------------------------------19、Which of the following is NOT an instance of market failure?A. A bad harvest increases the price of oranges.B. Production of a good generates pollution.C. Consumption of a good generates pollution.D. Precious gems are sold under monopoly conditions.--------------------------------------------------------------------------------20、Market failure arises when the market fails toA. provide a profit for all firms who produce the good.B. provide the good for all consumers who desire it.C. achieve an efficient outcome.D. prevent the price of a good from rising in response to an increase in demand.。
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A Labour Market with a Minimum Wage
Minimum Wage Brings Unemployment If the minimum wage is set above the equilibrium wage rate, the quantity of labour supplied by workers exceeds the quantity demanded by employers. There is a surplus of labour. The quantity of labour hired at the minimum wage is less than the quantity that would be hired in an unregulated labour market. Because the legal wage rate cannot eliminate the surplus, the minimum wage creates unemployment.
A Housing Market with a Rent Ceiling
Increased Search Activity The time spent looking for someone with whom to do business is called search activity. When a price is regulated and there is a shortage, search activity increases. Search activity is costly and the opportunity cost of housing equals its rent (regulated) plus the opportunity cost of the search activity (unregulated). Because the quantity of housing is less than the quantity in an unregulated market, the opportunity cost of housing exceeds the unregulated rent.
When a price ceiling is applied to a housing market it is called a rent ceiling. If the rent ceiling is set above the equilibrium rent, it has no effect. The market works as if there were no ceiling. But if the rent ceiling is set below the equilibrium rent, it has powerful effects.
The equilibrium rent is $1,000 a month. A rent ceiling is set at $800 a month. So the equilibrium rent is in the illegal region.
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A deadweight loss arises.
Producer surplus shrinks. Consumer surplus shrinks. There is a potential loss from increased search activity.
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Chapter 6: Government Actions in Markets
In this session, we will learn how interventions in free working of markets can create efficiency loss
In particular, we will focus on the following:
A Labour Market with a Minimum Wage
A price floor is a regulation that makes it illegal to trade at a price lower than a specified level. When a price floor is applied to labour markets, it is called a minimum wage. If the minimum wage is set below the equilibrium wage rate, it has no effect. The market works as if there were no minimum wage. If the minimum wage is set above the equilibrium wage rate, it has powerful effects.
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A Housing Market with a Rent Ceiling
Because the legal price cannot eliminate the shortage, other mechanisms operate:
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A Labour Market with a Minimum Wage
The quantity of labour supplied exceeds the quantity demanded and unemployment is created. With only 20 million hours demanded, some workers are willing to supply the last hour demanded for $8.
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A Housing Market with a Rent Ceiling
A rent ceiling decreases the quantity of housing supplied to less than the efficient quantity.
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A Housing Market with a Rent Ceiling
A Black Market A black market is an illegal market that operates alongside a legal market in which a price ceiling or other restriction has been imposed. A shortage of housing creates a black market in housing. Illegal arrangements are made between renters and landlords at rents above the rent ceiling—and generally above what the rent would have been in an unregulated market.
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A Labour Market with a Minimum Wage
The equilibrium wage rate is $9 an hour.
The minimum wage rate is set at $10 an hour. So the equilibrium wage rate is in the illegal region. The quantity of labour employed is the quantity demanded.
How rent ceilings create housing shortages and inefficiency
How minimum wage laws create unemployment and inefficiency The effects of a tax
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A Housing Market with a Rent Ceiling
At the rent ceiling, the quantity of housing demanded exceeds the quantity supplied.
There is a shortage of housing.
Increased search
activity
A black market
With the shortage, someone is willing to pay up to $1,200 a month.