人大版微观经济学(第三版)课后答案第7-8章

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微观经济学第7章课后计算题答案

1、已知某完全竞争行业中的单个厂商的短期成本函数为STC=0.1Q 3-2Q 2+15Q+10。

试求：（1）当市场上产品的价格为P=55时，厂商的短期均衡产量和利润；（2）当市场价格下降为多少时，厂商必须停产？（3）厂商的短期供给函数。

解答：（1）因为STC=0.1Q 3-2Q 2+15Q+10所以SMC=dQdSTC =0.3Q 3-4Q+15 根据完全竞争厂商实现利润最大化原则P=SMC ，且已知P=55，于是有：0.3Q 2-4Q+15=55整理得：0.3Q 2-4Q-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即厂商短期均衡的产量Q *=20，利润л=790（2）当市场价格下降为P 小于平均可变成本AVC 即P ≤AVC 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成本AVC 。

根据题意，有： AVC=QQ Q Q Q TVC 1521.023+-==0.1Q 2-2Q+15 令即有,0=dQ dAVC ：022.0=-=Q dQdAVC 解得 Q=10 且02.022 =dQAVC d 故Q=10时，AVC （Q ）达最小值。

以Q=10代入AVC （Q ）有：最小的可变平均成本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则P=SMC ，有：0.3Q 2-4Q+15=p整理得 0.3Q 2-4Q+（15-P ）=0 解得6.0)15(2.1164P Q --±= 根据利润最大化的二阶条件C M R M '' 的要求，取解为： Q=6.022.14-+P考虑到该厂商在短期只有在P 时5≥才生产，而P ＜5时必定会停产，所以，该厂商的短期供给函数Q=f （P ）为： Q=6.022.14-+P ，P 5≥ Q=0 P ＜52、已知某完全竞争的成本不变行业中的单个厂商的长期总成本函数LTC=Q 3-12Q 2+40Q 。

微观经济学习题及答案(高鸿业-人大版)

第1章绪论一、单项选择题1．经济学可定义为（ C ）A、政府对市场制度的干预B、企业取得利润的活动C、研究如何最合理地配置稀缺资源于诸多用途D、人们靠收入生活2．经济学研究的基本问题是（D ）A、怎样生产B、生产什么,生产多少C、为谁生产D、以上都包括3．说“资源是稀缺的”是指（ B ）A、世界上大多数人生活在贫困中B、相对于资源的需求而言,资源总是不足的C、资源必须保留给下一代D、世界上资源最终将由于生产更多的物品和劳务而消耗光4．人们在进行决策时，必须作出某种选择，这是因为（B ）A、选择会导致短缺B、人们在进行决策时面临的资源是有限的C、人是自私的,所作出的选择会实现自身利益的最大化D、个人对市场的影响是微不足道的5．下列问题（ C ）是经济学研究不会涉及的问题A、在稀缺资源约束条件下，实现资源有效配置的方法B、如何实现中国人均收入翻两番C、中国传统文化的现代化问题D、充分就业和物价水平的稳定6．一国生产可能性曲线以内的一点表示（ B ）A、通货膨胀B、失业或资源没有被充分利用C、该国可利用的资源减少以及技术水平降低D、一种生产品最适度水平7．下列各项中( C ）会导致一国生产可能性曲线向外移动A、失业B、通货膨胀C、有用性资源增加或技术进步D、消费品生产增加,资本物品生产下降8．下列命题中（ C )不是实证经济学命题A、1982年8月联储把贴现率降到10%B、1981年失业率超过9%C、联邦所得税对中等收入家庭是不公平D、社会保险税的课税依据已超过30 000美元9．下列( B ）是规范经济学的说法A、医生挣的钱比蓝领工人多B、收入分配中有太多的不公平现象C、从1999年开始，中国的物价水平基本保持稳定状态,这一现象也许会保持到2005年D、如果在20世纪80年代中期你购买了微软公司的1000股股票，现在你愿意出售的话,你肯定赚不少钱10．由市场配置资源意味着( B )A、所有的人都会得到他想要的东西B、资源的配置是由市场机制实现的C、政府能够决定谁获得多少消费品D、要得到急需的物品你只能“走后门”11．西方学者认为现代美国经济是一种（ C )A、完全的自由放任经济制度B、严格的计划经济制度C、混合资本主义市场经济制度D、自给自足制度1-5 C D B B C 6-10 B C C B B11、C二、判断正误1．只有落后国家才存在资源的稀缺性和供给的短缺现象。

(完整word版)西方经济学(微观经济学)课后练习答案第八章

微观第八章习题一、名词解释引致需求联合需求边际产品价值边际收益产品边际要素成本完全竞争要素市场买方垄断卖方垄断二、选择题1、下列各项中不属于生产要素的是（ D ）A ．企业管理者的管理才能 B. 农民拥有的土地C ．用于生产的机器厂房 D. 在柜台上销售的服装2、完全竞争厂商对生产要素的需求曲线向右下方倾斜的原因在于（）A.要素的边际成本递减B.要素的边际产量递减C.要素生产的产品的边际效用递减D.要素参加生产的规模报酬递减3、在产品X 市场和要素K 、L 的市场都是完全竞争市场的厂商，利润最大化的条件是（ D ）A ．X X X P MC MC =，且上升B ．L K L KMP MP P P = C ．1L K L K X MP MP P P MC == D ．11L K L K X XMP MP P P MC P ===4、对于一个垄断企业（其所处要素市场是完全竞争的），投入品M 的价格为20元，边际产量为5，产品价格是4元，则这个企业的产量（）A.未达到利润最大化，应减少产量B.未达到利润最大化，应扩大产量C.生产出利润最大化，但是成本未达到最小化D.在成本最小条件下实现利润最大化产量5、市场中单个厂商对某种生产要素的需求曲线同全体厂商对该种生产要素的需求曲线之间的关系表现为（）A.两者是重合在一起的B.前者较后者平坦C.前者较后者陡峭D.无法确定6、在一个完全竞争的市场中，追求利润最大化的厂商的产品价格上升时，将引起劳动的边际产品价值（），从而导致劳动的需求曲线（）A.降低，右移B.增加，左移C.增加，右移D.降低，左移7、完全竞争产品市场与不完全竞争产品市场两种情况下的生产要素的需求曲线相比( )A. 前者比后者陡峭B. 前者与后者重合C. 后者比前者平坦D. 均有可能8、假定生产要素A 、B 、C 的边际产量分别是20、16、8，它们的价格分别是10、8、4，那么这一生产要素的组合（ C ）A ．不是最小成本的组合B ．是最小成本的组合C ．是否为最小成本组合，视不同的要素市场而定D ．是否为最小成本组合，视不同的产品市场和要素市场而定9、假定两种生产要素X 和Y 的价格为30元，18元，产品的边际收益是3元，那么当这两种要素的边际产量为（ B ）时，该生产商才能获得最大利润。

微观经济学第七章习题答案

MR，试求：图7—1(1)A点所对应的MR值；(2)B点所对应的MR值。

解答：(1)根据需求的价格点弹性的几何意义，可得A点的需求的价格弹性为e d ＝eq \f(15－5,5)＝2或者e d ＝eq \f(2,3－2)＝2再根据公式MR＝P eq \b\lc$\rc$(\a\vs4\al\co1(1－\f(1,e d )))，则A点的MR值为MR＝2×eq \b\lc$\rc$(\a\vs4\al\co1(1－\f(1,2)))＝1(2)与(1)类似，根据需求的价格点弹性的几何意义，可得B点的需求的价格弹性为e d ＝eq \f(15－10,10)＝eq \f(1,2)或者e d ＝eq \f(1,3－1)＝eq \f(1,2)再根据公式MR＝P eq \b\lc$\rc$(\a\vs4\al\co1(1－\f(1,e d )))，则B点的MR值为MR＝1×eq \b\lc$\rc$(\a\vs4\al\co1(1－\f(1,1/2)))＝－12. 图7—2(即教材第205页的图7—19)是某垄断厂商的长期成本曲线、需求曲线和收益曲线。

试在图中标出：(1)长期均衡点及相应的均衡价格和均衡产量；(2)长期均衡时代表最优生产规模的SAC曲线和SMC曲线；(3)长期均衡时的利润量。

图7—2图7—3(1)长期均衡点为E点，因为在E点有MR＝LMC。

由E点出发，均衡价格为P0，均衡数量为Q0。

(2)长期均衡时代表最优生产规模的SAC曲线和SMC曲线如图7—3所示。

在Q0的产量上，SAC曲线和LAC曲线相切；SMC曲线和LMC曲线相交，且同时与MR曲线相交。

(3)长期均衡时的利润量由图7—3中阴影部分的面积表示，即π＝[AR(Q0)－SAC(Q0)]·Q 0。

3. 已知某垄断厂商的短期总成本函数为STC＝0.1Q3－6Q2＋140Q＋3 000，反需求函数为P＝150－3.25Q。

微观经济学第第七章课后答案资料

微观经济学第第七章课后答案第7章课后练习答案一、基本概念 1、一般均衡：经济中所有经济单位及其市场同时处于均衡的一种状态。

2、帕累托最优条件：1）交换的帕累托最化条件：A B XY XY MRS MRS = ；2）生产的帕累托最优条件：C D LK LK MRTS MRTS = ；3）交换和生产的帕累托最优条件：XY XY MRS MRT = 3、帕累托改进：在资源既定的情况下，如果经济社会通过资源重新配置可以在不使得他人境况受到损害的条件下使得某些人的境况得到改善，则社会福利得到增进。

二、分析简答1、什么是局部均衡和一般均衡，两者的区别和联系是什么？答：局部均衡是指：仅仅是某一种产品实现了均衡或某一种市场(例如，产品市场或要素市场)实现了均衡。

一般均衡是指经济中所有经济单位及其市场同时处于均衡的一种状态。

局部均衡把市场上其他商品和生产要素的数量与价格对这种商品或生产要素价格的影响忽略不计或视为不变，即假定这一商品或生产要素的价格只取决于它本身的供求状况，而不受其他商品的价格和供求状况的影响。

而在一般均衡分析中，不仅要分析影响该商品价格变动的供求关系，还要分析影响该商品生产的生产要素市场、消费者收入等多种因素的影响，即把经济中的所有经济单位和所有市场联系起来加以考虑和分析。

2、为什么完全竞争可以实现帕累托最优所需具备的三个条件？完全竞争经济在一定的假设条件下存在着一般均衡，即存在一组价格，在该组价格下市场中的供求平衡。

假设该组价格为Px ，P Y ，…，P L ，P K ，…。

其中P X ，P Y ，…表示商品X ，Y ，…的均衡价格；P L ，P K ，…表示要素L ，K ，…的均衡价格。

在完全竞争条件下，每个消费者和生产者都是价格的接受者，消费者在既定价格下追求自身效用的最大化，生产者在既定价格下追求自身利润的最大化。

对于消费者而言，任意一个消费者在完全竞争经济中效用最大化的条件是任意两种商品的边际替代率等于两种商品的价格比率，对于消费者C ，有：/A XY X Y MRS P P = ；对于消费者B ，有： /B XY X Y MRS P P =；将以上两式整理可得：A B XY XY MRS MRS =；此公式就是交换的帕累托最优条件。

中国人民大学经济学考研笔记高鸿业《西方经济学》(第三版)课后题答案解析

பைடு நூலகம்
11、短期均衡条件：MR=SMC MR=TR’＝（P·Q） ’＝150-6.5Q，SMC=STC’=0.3Q2-12Q+140 得 Q=20 或者 Q=-5/3 由于产量不能为负数，所以均衡产量为 Q=20 P=150-3.25*20＝85 第八章 7、厂商利润最大：要素的边际收益=要素的边际成本即：VMP=W， VMP=MQ·P，MQ=dQ/dL＝-0.03L +2L+36
由（1）、（2）式的方程组，可以得到 X1=9，X2=12 （2）U=3X1X2 =3888 8、（1）A 消费者的需求表为： P QAd 5 0 4 4 3 8 2 12 1 16 0 20
2
B 消费者的需求表为： P QBd 6 0 5 5 4 10 3 15 2 20 1 25 0 30
中国考研专业课辅导第一品牌
3 4 5 6 7 (4)\(5)略。 5、（1）可变成本部分为 VC=Q3-10Q2+17Q；不变成本部分为 66 TVC(Q)= Q3-10Q2+17Q AC(Q)= Q2-10Q+17+66/Q AVC(Q)= Q2-10Q+17 AFC(Q)= AVC(Q) MC(Q)=3Q2-20Q+17 6、AVC(Q)= 0.04Q2-0.8Q+10 令上述函数的一阶导数为零，可以得到 0.08Q-0.8=0,Q=10 AVC(10)=0.04*102-0.8*10+10=6 或者 MC=AVC 时，AVC 最小，有 0.04Q2-0.8Q+10＝0.12Q2-1.6Q+10 得到 Q=10,结果一样。第六章 2、（1）2 （2）4 （3）2 （4）4 （5）3 （6）4 （7）4 70 100 120 130 135 600 800 1000 1200 1400 60/7 8 100/12 120/13 1400/135 5 20/3 10 20 40

微观课后习题参考答案7-8

第七章复习题参考答案1、如果政策没有效率，那么根据定义，它可以进行改进使得至少一个人受益而不损害任何人的利益。

因此，经济学家强调效率，是因为它能够节省资源，增进社会福利。

2、就这个政策本身而言，它并不能够在不损害任何人利益的情况下，改善某些人的福利。

但是假设我们增加一个配套政策，比如对这些福利改善的工人增收5百万的税，用于补贴退休人员，这样，我们可以看到，所有的人的福利都改善了。

3、因为部分税收将以社会公共品的形式返回社会，所以市场参与者的经济剩余损失大于整个社会的经济剩余的损失。

（这道题比较拗口，它想比较的是市场参与者的经济剩余损失VS全社会的经济剩余损失。

）4、补偿政策使得那些时间机会成本较小的乘客自愿放弃，因此对于整个社会的资源配置而言更有效率。

5、价格上限使得生产者的产量低于边际成本等于边际受益时候的均衡产量，也就是说也就是说市场出现短缺，生产者本来还可以继续生产，因为其边际成本低于消费者所愿意支付的价格，因此价格上限减少了经济剩余。

练习题参考答案1、(1)消费者剩余等于消费曲线与价格线的三角形面积，即0.5*1.5*6＝$4.5。

(2)类似的生产者剩余：0.5*4.5*6＝$13.5。

(3)因为这个交易，整个社会增加的经济剩余为4.5+13.5=$18，这就是生产者和消费者所愿意付出的最大价格。

2、(1)在$7.50的价格上限下，供给为2，需求为18，短缺量为16。

(2)由于价格上限所造成的经济损失为下图的黑色三角形ABC和ACD，即0.5*4*1＋0.5*4*3＝$8。

24863、(1)按照先到先得的分配原则，对于得到游览机会的四个人的经济总剩余为：20+14+30+15=79。

(2)如果进行补偿，根据题目要求，$15的补偿金将使3人放弃该游览机会。

由于补偿金是从风景区转移到游客身上，所以整个社会的经济剩余不变，但是得到游览机会的4个人的经济总剩余变成了40+30+20+17＝$107——高于先到先得原则。

西方经济学（微观经济学）课后练习答案第七章

西⽅经济学（微观经济学）课后练习答案第七章微观第七章习题⼀、名词解释完全垄断市场垄断竞争市场寡头市场价格歧视博弈纳什均衡占优策略均衡⼆、选择题1、对于垄断⼚商来说，（）。

A、提⾼价格⼀定能够增加收益；B、降低价格⼀定会减少收益；C、提⾼价格未必会增加收益，降低价格未必会减少收益；D、以上都不对。

2、完全垄断的⼚商实现长期均衡的条件是（）。

A、MR=MC；B、MR=SMC=LMC；C、MR=SMC=LMC=SAC；D、MR=SMC=LMC=SAC=LAC。

3、完全垄断⼚商的总收益与价格同时下降的前提条件是（）。

A、Ed>1；B、Ed<1；C、Ed=1；D、Ed=0。

4、完全垄断⼚商的产品需求弹性Ed=1时（）。

A、总收益最⼩；B、总收益最⼤；C、总收益递增；D、总收益递减。

5、完全垄断市场中如果A市场的价格⾼于B市场的价格，则（）A、A市场的需求弹性⼤于B市场的需求弹性；B、A市场的需求弹性⼩于B市场的需求弹性；C、A市场的需求弹性等于B市场的需求弹性；D、以上都对。

6、以下关于价格歧视的说法不正确的是（）。

A、价格歧视要求垄断者能根据消费者的⽀付意愿对其进⾏划分；B、⼀级价格歧视引起⽆谓损失；C、价格歧视增加了垄断者的利润；D、垄断者进⾏价格歧视，消费者就必定不能进⾏套利活动。

7、垄断竞争的⼚商短期均衡时，（）。

A、⼀定能获得差额利润；B、⼀定不能获得经济利润；C、只能得到正常利润；D、取得经济利润、发⽣亏损和获得正常利润都有可能。

8、垄断竞争⼚商长期均衡点上，长期平均成本曲线处于（ B ）A、上升阶段B、下降阶段C、⽔平阶段D、以上三种情况都有可能9、垄断竞争⼚商实现最⼤利润的途径有：（ D ）A、调整价格从⽽确定相应产量B、品质竞争C、⼴告竞争D、以上途径都可能⽤10、按照古诺模型下列哪⼀说法不正确，（）。

A、双头垄断者没有认识到他们的相互依耐性；B、每⼀个寡头都认定对⽅的产量保持不变；C、每⼀个寡头垄断者都假定对⽅价格保持不变；D、均衡的结果是稳定的。

微观经济学第七章答案

微观经济学第七章答案【篇一：微观经济学各校考研试题及答案整理第七章】>1概念题1.混合策略（mixed strategies）（中山大学2004试）2．囚犯两难处境（人大1999试）3．纳什均衡（nash equilibrium）（华东师大2004试；南京大学2005试；中国海洋大学2002试；华中科大2002试；北师大2005试；厦门大学2006试；北航2006试；东华大学2006试）4．占优均衡（dominant equilibrium）与纳什均衡（nash equilibrium）（北大1997；1998年试；中山大学2005试；东北财经大学2006试）5．双垄断（duopoly）（复旦大学1998试）6．折拐的需求曲线（kinky demand curve）（人大1998试）7．串谋8．价格领导9．寡头价格（oligopoly price）10．贝叶斯纳什均衡（bayesian-nash equilibrium）2 简答题1．解释卡特尔组织不稳定性的原因。

（北航2004试）2．说明纳什均衡与纳什定理的基本概念。

（南开大学2005试）3．对比其他市场结构，说明不能建立一般的寡头模型的原因。

（天津财经学院2000试）4．请用博弈论思想简述中国为什么要加入世界贸易组织？（对外经贸大学2002试）5．两家计算机厂商a和b正计划推出用于办公室信息管理的网络系统。

各厂商都既可以开发一种高速、高质量的系统（h），也可以开发一种低速、低质量的系统（l）。

市场试究表明各厂商在不同策略下相应的利润由如下得益矩阵给出。

厂商bh lh 厂商a l（1）如果两厂商同时作决策且用极大化极小（低风险）策略，结果将是什么？（2）假设两厂商都试图最大化利润，且a先开始计划并实施，结果会怎样？如果b先开始，结果又会如何？（上海交大2004试）6．下面的矩阵表示两个厂商选择的策略的支付矩阵（单位：万元） b守约违约守约 a 违约（1）哪一种策略使a的最大可能损失为最小？b的是哪一种？（2）如果你是a，你会选择哪一种策略？为什么？如果a违约，b会做什么？如果b违约，a会做什么？（3）这一对策最可能出现的结果是什么？为什么？7．完全垄断与寡头垄断的区别。

黄亚钧《微观经济学》(第3版)习题详解(第8章劳动市场)

黄亚钧《微观经济学》（第3版）第八章劳动市场课后习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。

以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。

1．在工资率为每小时12元时，小李乐意在一年内工作任意小时。

（1）以工作——闲暇图画出小李的预算约束线；（2）假设小李有个富有的叔叔，无论小李赚多少钱，每年都给他1000元，试画出与其相应的预算约束线；（3）用无差异曲线图来揭示小李的叔叔的收入如何影响小李工作时间。

答：（1）如图8-11所示，小李的预算约束线为AB。

（2）此时的预算约束线为A B''。

（3）由于有了叔叔给的1000元，小李的预算约束线AB在I轴向上平移1000到''A B，假设原无差异曲线U与AB切于E，现在无差异曲线U＇与A B''切于E'。

由于AB平行于A B''，所以E'必定位于E的右上方，则意味着小李由于有了这笔钱，将会有增加闲暇时间、减少工作时间的动机。

图8-11 预算约束线和无差异曲线2．如果某人意外地接受了一笔财产，他的收入—闲暇预算线有何变化？工作时间上升了还是下降了？答：若意外地接受了一笔财产，收入—闲暇预算线将向正上方平移，平移量等于该财产量。

因此，他可能会增加闲暇时间，工作时间下降。

3．一个行业面临着竞争的劳动市场，劳动的供给来自本国工人和外国工人两个来源，所有的工人都有相同的技能，同时假定该行业的产品要与进口品竞争。

（1）作图说明最初的竞争劳动市场，画出劳动的需求曲线和供给曲线，并确定均衡的工资率与就业水平。

（2）假定本国工人组成了工会，工会支持禁止企业雇用外国工人的法律。

(完整word版)西方经济学(微观经济学)课后练习答案第八章(word文档良心出品)

(完整版)微观经济学课后习题答案

第一章答案二、选择题1.B2.D3.C4.C5.D6.B7.C8.A三、简答题1.微观经济学的假设前提是什么？答：微观经济学有四个假设前提：资源稀缺性、市场出清、完全理性、完全信息2.微观经济学有什么特点？答：微观经济学的特点：（1）用数学语言描述经济现象与规律；（2）以价格理论为核心；（3）以均衡为目标；（4）理论与现实紧密结合3.微观经济学要解决什么样的问题？答：微观经济学要解决的三大基本问题是：生产什么，生产多少；如何生产；为谁生产。

4.微观经济学的研究对象是什么？答：微观经济学的研究对象是个体经济单位。

具体从三个层面展开的：第一个层面：分析单个消费者、单个要素供给者和单个生产者的经济行为。

第二个层面：研究单个市场的价格决定（局部均衡）。

第三个层面：研究所有市场的价格同时决定。

四、论述题1.请介绍微观经济学的新发展。

答：微观经济学的新发展体现在理论上新发展、方法上新发展和微观经济学发展的新趋势三个方面。

理论上的新发展主要体现在：（1）提出了新消费理论，包括显示性偏好理论、风险条件下的选择理论、消费也是家庭生产的理论；（2）提出了现代企业理论，包括企业的性质、最大化模型与委托——代理问题、内部组织效率与非最大化厂商理论；（3）博弈论改写了微观经济学；（4）信息经济学成为微观经济分析的主流。

方法上的新发展主要体现在三个方面：一是计量经济学的崛起，二是统计学在经济学中的大规模运用，三是博弈论引入到经济学。

微观经济学发展的新趋势包括：（1）假定条件多样化，（2）研究领域的非经济化，（3）学科交叉的边缘化。

2.微观经济学与宏观经济学有何区别？答：微观经济学与宏观经济学的区别体现在：（1）研究对象不同。

微观经济学的研究对象是单个经济单位，二宏观经济学的研究对象则是整个经济，研究整个经济的运行方式与规律，从总量上分析经济问题。

（2）解决的问题不同。

微观经济学要解决的是资源配置问题，而研究社会范围内的资源利用问题，以实现社会福利的最大化。

微观经济学课后习题答案第七章完整版

微观经济学课后习题答案第七章HEN system office room 【HEN16H-HENS2AHENS8Q8-HENH1688】第七章复习思考题参考答案1、为什么垄断厂商的需求曲线是向右下方倾斜的？并解释相应的TR 曲线、AR 曲线和MR 曲线的特征以及相互关系。

解答：垄断厂商所面临的需求曲线是向右下方倾斜的，其理由主要有两点：第一，垄断厂商所面临的需求曲线就是市场的需求曲线，而市场需求曲线一般是向右下方倾斜的，所以垄断厂商的需求量与价格成反方向的变化。

第二，假定厂商的销售量等于市场的需求量，那么，垄断厂商所面临的向右下方倾斜的需求曲线表示垄断厂商可以通过调整销售量来控制市场的价格，即垄断厂商可以通过减少商品的销售量来提高市场价格，也可以通过增加商品的销售量来降低市场价格。

关于垄断厂商的TR 曲线、AR 曲线和MR 曲线的特征以及相互关系，以图7-1加以说明：第一，平均收益AR 曲线与垄断厂商的向右下方倾斜的d 需求曲线重叠。

因为，在任何的销售量上，都是P=AR 。

第二，边际收益MR 曲线是向右下方倾斜的，且位置低于AR 曲线。

其原因在于AR 曲线是一条下降的曲线。

此外，在线性需求曲线的条件下，AR 曲线和MR 曲线的纵截距相同，而且MR 曲线的斜率的绝对值是AR 曲线的斜率的绝对值的两倍。

第三，由于MR 值是TR 曲线的斜率，即dQdTR MR =，所以，当MR>0时，TR 曲线是上升的；当MR ＜0时，TR 曲线是下降的；当MR=0时，TR 曲线达极大值。

图 7-1 垄断竞争厂商的AR 与TR 之间的关系2、根据图7-22中线性需求曲线d 和相应的边际收益曲线MR ，试求：（1）A 点所对应的MR 值；（2）B 点所对应的MR 值。

解答：（1）根据需求的价格点弹性的几何意义，可得A 点的需求的价格弹性为：25)515(=-=d e ，或者，2)23(2=-=d e ，根据)11(d e P MR -=，则A 点的MR 值为：MR=2×（2×1/2）=1。

第7-9章微观经济学习题答案

第7章生产理论习题答案1.名词解释生产函数：在一定时间范围内和生产技术水平不变的情况下，各种生产要素数量组合与其所能生产的最大产量之间的关系。

边际报酬递减规律：在技术水平不变的条件下，把某一种可变生产要素增加到其他一种或几种数量不变的生产要素上去的过程中，当该生产要素的投入数量增加到一定程度以后，单位生产要素投入增加所带来的边际产量终会出现递减。

边际技术替代率：在维持产量水平不变的条件下，增加一单位某种生产要素投入量时所减少的另一种要素的投入数量。

边际技术替代率是递减的，表示在保持产量不变的前提下，某要素投入量越少，越不容易被另外的要素所替代。

等产量曲线:是指在技术水平不变的条件下生产出相同产量的两种生产要素投入量的各种组合的轨迹。

等成本线:是指在既定的成本和既定生产要素价格条件下生产者可以购买到的两种生产要素的各种不同数量组合的轨迹。

规模报酬:分析的是企业的生产规模的改变与所引起的产量变化之间的关系。

如果因生产要素同比例增加而引起的产量增加的比例大于要素增加的比例，那么，生产呈现规模报酬递增;如果因生产要素同比例增加而引起的产量增加的比例等于要素增加的比例，那么生产呈现规模报酬不变;如果因生产要素同比例增加而引起的产量增加的比例小于要素增加的比例，那么生产则是规模报酬递减的。

2.单项选择（1）B、（2）C、（3）A、（4）A、（5）A 、（6）C、（7）D、（8）B、（9）B、（10）D、（11）A、（12）B、（13）D、（14）A、（15）C。

3.多项选择 (1)ABCE； (2)ABCDE； (3)BD； (4)BCD； (5)ABC；4.简答题(1)一个企业主在考虑再雇佣一名工人时，在劳动的平均产量和边际产量中他将更关心劳动的边际产量。

我们知道，厂商的理性决策在劳动的第二阶段。

在这个区域中，劳动的平均产量及边际产量都是递减的，但其中却可能存在着使利润极大化的点，劳动的第二阶段的右界点是使劳动的边际产量为零的点。

平狄克《微观经济学》课后答案 7-8

CHAPTER 7THE COST OF PRODUCTIONIn this chapter, it is easy for the students to concentrate too much on definitions and geometry and lose focus on the economics. Therefore, keep in mind the key concepts: opportunity cost, short-run average and marginal cost, cost minimization, and long-run average cost. These concepts can be illuminated with the supplementary material provided at the end of the chapter, which includes sections on economies of scope, learning curves, and estimating and predicting costs. The Appendix presents the calculus of constrained optimization, as applied to cost minimization. All exercises involve some algebra or geometry: Exercises (12) and (13) are time consuming, but rewarding.Opportunity cost is the conceptual base of this chapter. While most students think of costs in accounting terms, they must develop an understanding of the distinction between accounting, economic, and opportunity costs. One source of confusion is the opportunity cost of capital, i.e., why the rental rate on capital must be considered explicitly by economists. It is important, for example, to distinguish between the purchase price of capital equipment and the opportunity cost of using the equipment. The opportunity cost of a person’s tim e also leads to some confusion for students.Following the discussion of opportunity cost, the chapter diverges in two directions: one path introduces types of cost and cost curves, and the other focuses on cost minimization. Both directions converge with the discussion of long-run average cost.The geometry of total, fixed, variable, average, and marginal costs can prove to be tedious. An emphasis on the following issues helps students master this topic: 1) the relationship between the production function, diminishing returns in the short run, input prices, and the shapes of the various cost curves; 2) the distinction between total, average, and marginal; and 3) the reasonableness of the assumption of constant input prices (note that this assumption w ill be relaxed in Chapter 10’s discussion of monopsony). The determination of the cost-minimizing quantity is crucial to understanding Chapters 8 and 10. The concept of duality (minimizing cost subject to a given level of production) is equivalent to maximizing output subject to a given level of total cost) clarifies this concept for students.A clear understanding of short-run cost and cost minimization is necessary for the derivation of long-run average cost. With long-run costs, stress that firms are operating on short-run cost curves at each level of the fixed factor and that long-run costs do not exist separately from short-run costs. Exercise (6) illustrates the relationship between long-run cost and cost minimization, with an emphasis on the importance of the expansion path. Stress the connection between the shape of a long-run cost curve and returns to scale. While Section 7.7 is starred, it does not require calculus. Example 7.5 “Cost Functions for Electric Power,” gives students another vie w of long-run average cost and allows for discussion of minimum efficient scale, an important determinant of industry structure.1. A firms pays its accountant an annual retainer of $10,000. Is this an explicit or implicit cost?Explicit costs are actual outlays. They include all costs that involve a monetary transaction.An implicit cost is an economic cost that does not necessarily involve a monetary transaction, butstill involves the use of resources. When a firm pays an annual retainer of $10,000, there is amonetary transaction. The accountant trades his or her time in return for money. Therefore,an annual retainer is an explicit cost.2. The owner of a small retail store does her own accounting work. How would you measure the opportunity cost of her work?Opportunity costs are measured by comparing the use of a resource with its alternative uses.The opportunity cost of doing accounting work is the time not spent in other ways, i.e., time suchas running a small business or participating in leisure activity. The economic cost of doingaccounting work is measured by computing the monetary amount that the time would be worth inits next best use.3. Suppose a chair manufacturer finds that the marginal rate of technical substitution of capital for labor in his production process is substantially greater than the ratio of the rental rate on machinery to the wage rate for assembly-line labor. How should he alter his use of capital and labor to minimize the cost of production?To minimize cost, the manufacturer should use a combination of capital and labor so the rate atwhich he can trade capital for labor in his production process is the same as the rate at which hecan trade capital for labor in external markets. The manufacturer would be better off if heincreased his use of capital and decreased his use of labor, decreasing the marginal rate oftechnical substitution, MRTS. He should continue this substitution until his MRTS equals theratio of the rental rate to the wage rate.4. Why are isocost lines straight lines?The isocost line represents all possible combinations of labor and capital that may be purchasedfor a given total cost. The slope of the isocost line is the ratio of the input prices of labor andcapital. If input prices are fixed, then the ratio of these prices is clearly fixed and the isocost lineis straight. Only when the ratio or factor prices change as the quantities of inputs change is theisocost line not straight.5. If the marginal cost of production is increasing, does this tell you whether the average variable cost is increasing or decreasing? Explain.Marginal cost can be increasing while average variable cost is either increasing or decreasing. Ifmarginal cost is less (greater) than average variable cost, then each additional unit is adding less(more) to total cost than previous units added to the total cost, which implies that the AVCdeclines (increases). Therefore, we need to know whether marginal cost is greater than averagecost to determine whether the AVC is increasing or decreasing.6. If the marginal cost of production is greater than the average variable cost, does this tell you whether the average variable cost is increasing or decreasing? Explain.If the average variable cost is increasing (decreasing), then the last unit produced is adding more(less) to total variable cost than the previous units did, on average. Therefore, marginal cost isabove (below) average variable cost. If marginal cost is above average variable cost, averagevariable cost is also increasing.7. If the firm’s average cost curves are U-shaped, why does its average variable cost curve achieve its minimum at a lower level of output than the average total cost curve?Total cost is equal to fixed plus variable cost. Average total cost is equal to average fixed plusaverage variable cost. When graphed, the difference between the U-shaped total cost andaverage variable cost curves is the average fixed cost curve. If fixed cost is greater than zero, theminimum of average variable cost must be less than the minimum average total cost.8. If a firm enjoys increasing returns to scale up to a certain output level, and then constant returns to scale, what can you say about the shape of the firm’s long-run average cost curve?When the firm experiences increasing returns to scale, its long-run average cost curve isdownward sloping. When the firm experiences constant returns to scale, its long-run averagecost curve is horizontal. If the firm experiences increasing returns to scale, then constantreturns to scale, its long-run average cost curve falls, then becomes horizontal.9. How does a change in the price of one input change the firm’s long-run expansion path?The expansion path describes the combination of inputs for which the firm chooses to minimizecost for every output level. This combination depends on the ratio of input prices: if the price ofone input changes, the price ratio also changes. For example, if the price of an input increases,less of the input may be purchased for the same total cost. The intercept of the isocost line onthat input’s axis moves closer to the origin. Also, the slope of the isocost line, the price ratio,changes. As the price ratio changes, the firm substitutes away from the now more expensiveinput toward the cheaper input. Thus, the expansion path bends toward the axis of the nowcheaper input. See Exercise (7.6).10. Distinguish between economies of scale and economies of scope. Why can one be present without the other?Economies of scale refer to the production of one good and occur when proportionate increases inall inputs lead to a more-than-proportionate increase in output. Economies of scope refer to theproduction of more than one good and occur when joint output is less costly than the sum of thecosts of producing each good or service separately. There is no direct relationship betweenincreasing returns to scale and economies of scope, so production can exhibit one without theother. See Exercise (13) for a case with constant product-specific returns to scale andmultiproduct economies of scope.1. Assume a computer firm’s marginal costs of production are constant at $1,000 per computer. However, the fixed costs of production are equal to $10,000.a. Calculate the firm’s average variable cost and average total cost curves.The variable cost of producing an additional unit, marginal cost, is constant at $1,000, so theaverage variable cost is constant at $1,000, ()000,1$000,1$=QQ . Average fixed cost is $10,000Q. Average total cost is the sum of average variable cost and average fixed cost: ATC Q=+$1,$10,.000000 b. If the firm wanted to minimize the average total cost of production, would it choose to be verylarge or very small? Explain.The firm should choose a very large output because average total cost decreases with increase inQ . As Q becomes infinitely large, ATC will equal $1,000.2. If a firm hires a currently unemployed worker, the opportunity cost of utilizing t he worker’s service is zero. Is this true? Discuss.From the worker’s perspective, the opportunity cost of his or her time is the time not spent inother ways, including time spent in personal or leisure activities. Certainly, the opportunity costof hiring an unemployed mother of pre-school children is not zero! While it might be difficult toassign a monetary value to the time of an unemployed worker, we can not conclude that it is zero.From the perspective of the firm, the opportunity cost of hiring the worker is not zero, and thefirm could purchase a piece of machinery rather than hiring the worker.3.a. Suppose that a firm must pay an annual franchise fee, which is a fixed sum, independent of whether it produces any output. How does this tax aff ect the firm’s fixed, marginal, and average costs?Total cost, TC , is equal to fixed cost, FC , plus variable cost, VC . Fixed costs do not vary with thequantity of output. Because the franchise fee, FF , is a fixed sum, the firm’s fixed costs increaseby this fee. Thus, average cost, equal toFC VC Q +, and average fixed cost, equal to FC Q , increase by the average franchise fee FF Q. Note that the franchise fee does not affect average variable cost. Also, because marginal cost is the change in total cost with the production of anadditional unit and because the fee is constant, marginal cost is unchanged.3.b. Now suppose the firm is charged a tax that is proportional to the number of items it produces. Ag ain, how does this tax affect the firm’s fixed, marginal, and average costs?Let t equal the per unit tax. When a tax is imposed on each unit produced, variable costsincrease by tQ . Average variable costs increase by t , and because fixed costs are constant,average (total) costs also increase by t . Further, because total cost increases by t with eachadditional unit, marginal costs increase by t .4. A recent issue of Business Week reported the following:During the recent auto sales slump, GM, Ford, and Chrysler decidedit was cheaper to sell cars to rental companies at a loss than to lay offworkers. That’s because closing and reopening plants is expensive,partly because the auto makers’ current union contracts obligatethem to pay many wor kers even if they’re not working.When the article discusses selling cars “at a loss,” is it referring to accountingprofit or economic profit? How will the two differ in this case? Explainbriefly.When the article refers to the car companies selling at a loss, it is referring to accounting profit.The article is stating that the price obtained for the sale of the cars to the rental companies was less than their accounting cost. Economic profit would be measured by the difference of theprice with the opportunity cost of the cars. This opportunity cost represents the market valueof all the inputs used by the companies to produce the cars. The article mentions that the carcompanies must pay workers even if they are not working (and thus producing cars). Thisimplies that the wages paid to these workers are sunk and are thus not part of the opportunitycost of production. On the other hand, the wages would still be included in the accountingcosts. These accounting costs would then be higher than the opportunity costs and wouldmake the accounting profit lower than the economic profit.5. A chair manufacturer hires its assembly-line labor for $22 an hour and calculates that the rental cost of its machinery is $110 per hour. Suppose that a chair can be produced using 4 hours of labor or machinery in any combination. If the firm is currently using 3 hours of labor for each hour of machine time, is it minimizing its costs of production? If so, why? If not, how can it improve the situation?If the firm can produce one chair with either four hours of labor or four hours of capital,machinery, or any combination, then the isoquant is a straight line with a slope of -1 andintercept at K = 4 and L = 4, as depicted in Figure 7.5.The isocost line, TC = 22L + 110K has a slope of -=-2211002. when plotted with capital on the vertical axis and has intercepts at K TC =110 and L TC =22. The cost minimizing point is a corner solution, where L = 4 and K = 0. At that point, total cost is $88.6. Suppose the economy takes a downturn, and that labor costs fall by 50 percent and are expected to stay at that level for a long time. Show graphically how this change in the relative price of labor and capital affects the firm’s expansion path.Figure 7.6 shows a family of isoquants and two isocost curves. Units of capital are on the verticalaxis and units of labor are on the horizontal axis. (Note: In drawing this figure we have assumedthat the production function underlying the isoquants exhibits constant returns to scale, resultingin linear expansion paths. However, the results do not depend on this assumption.)If the price of labor decreases while the price of capital is constant, the isocost curve pivotsoutward around its intersection with the capital axis. Because the expansion path is the set ofpoints where the MRTS is equal to the ratio of prices, as the isocost curves pivot outward, theexpansion path pivots toward the labor axis. As the price of labor falls relative to capital, thefirm uses more labor as output increases.business when costs are cheaper and discourage off-peak business when costs are higher.Do you follow the consultant’s advice? Discuss.The consultant does not understand the definition of average cost. Encouraging ridership always decreases average costs, peak or off-peak. If ridership falls to 10, costs climb to $3.00 per rider. Further, during rush hour, the buses are full. How could more people get on? Instead, encourage passengers to switch from peak to off-peak times, for example, by charging higher prices during peak periods.MC 2 is the marginal cost of refining distillate up to the capacity constraint, Q 2. The shape of thetotal marginal cost curve is horizontal up to the lower capacity constraint. If the capacityconstraint of the distilling unit is lower than that of the hydrocracking unit, MC T is vertical at Q 1.If the capacity constraint of the hydrocracking unit is lower than that of the distilling unit, MC T isvertical at Q 2.9. You manage a plant that mass produces engines by teams of workers using assembly machines. The technology is summarized by the production function.Q 4 KLwhere Q is the number of engines per week, K is the number of assembly machines, and L is the number of labor teams. Each assembly machine rents for r = $12,000 per week and each team costs w = $3,000 per week. Engine costs are given by the cost of labor teams and machines, plus $2,000 per engine for raw materials. Your plant has a fixed installation of 10 assembly machines as part of its design.a. What is the cost function for your plant — namely, how much would it cost to produce Qengines? What are average and marginal costs for producing Q engines? How do average costs vary with output?K is fixed at 10. The short-run production function then becomes Q = 40 L. This implies that for any level of output Q, the number of labor teams hired will be L = Q / 40. The total cost function is thusgiven by the sum of the costs of capital, labor, and raw materials:TC(Q) = rK + wL + 2000Q = (12,000)(10) + (3,000)(Q/40) + 2,000 Q= 120,000 + 2,075QThe average cost function is then given by:AC(Q) = TC(Q)/Q = 120,000/Q + 2,075and the marginal cost function is given by:∂ TC(Q) / ∂ Q = 2,075Marginal costs are constant and average costs will decrease as quantity increases (due to the fixed cost of capital).b. How many teams are required to producing 80 engines? What is the average cost perengine?To produce Q = 80 engines we need L = Q/40 labor teams or L = 2. Average costs are given byAC(Q) = 120,000/Q + 2,075or AC = 3575 c. You are asked to make recommendations for the design of a new production facility. Whatwould you suggest? In particular, what capital/labor (K/L) ratio should the new plant accommodate? If lower average cost were your only criterion, should you suggest that the new plant have more production capacity or less production capacity that the plant you currently manage?We no longer assume that K is fixed at 10. We need to find the combination of K and L which minimizes costs at any level of output Q. The cost-minimization rule is given byMP r =MP w .KLTo find the marginal product of capital, observe that increasing K by 1 unit increases Q by 4L, so MP K = 4L. Similarly, observe that increasing L by 1 unit increases Q by 4K, so MP L = 4K. (Mathematically, MP K = ∆Q /∆K = 4L and MP L = ∆Q /∆L = 4K.) Using these formulas in the cost-minimization rule, we obtain:4L/r = 4K/w or K / L = w / r = 3,000 / 12,000 = 1/4The new plant should accommodate a capital to labor ratio of 1 to 4.The firm’s capital -labor ratio is currently 10/2 or 5. To reduce average cost, the firm should either use more labor and less capital to produce the same output or it should hire more labor and increase output.*10. A computer company’s cost function, which relates its average cost of product ion AC to its cumulative output in thousands of computers CQ and its plant size in terms of thousands of computers produced per year Q, within the production range of 10,000 to 50,000 computers is given byAC = 10 - 0.1CQ + 0.3Q.a. Is there a learning curve effect?The learning curve describes the relationship between the cumulative output and the inputsrequired to produce a unit of output. Average cost measures the input requirements per unit ofoutput. Learning curve effects exist if average cost falls with increases in cumulative output.Here, average cost decreases as cumulative output, CQ, increases. Therefore, there are learningcurve effects.b. Are there increasing or decreasing returns to scale?To measure scale economies, calculate the elasticity of total cost, TC, with respect to output, Q:ETCTCQQTCTCQMCACC ===∆∆∆∆.If this elasticity is greater (less) than one, then there are decreasing (increasing) returns to scale, because total costs are rising faster (slower) than output. From average cost we can calculate total and marginal cost:TC = Q(AC) = 10Q - (0.1)(CQ)(Q) + 0.3Q2, thereforeMCdTCdQCQ Q ==-+100106...Because marginal cost is greater than average cost (because 0.6Q > 0.3Q), the elasticity, EC, is greater than one; there are decreasing returns to scale. The production process exhibits a learningeffect and decreasing returns to scale.c. During its existence, the firm has produced a total of 40,000 computers and is producing 10,000computers this year. Next year it plans to increase its production to 12,000 computers. Will its average cost of production increase or decrease? Explain.First, calculate average cost this year:AC1= 10 - 0.1CQ + 0.3Q = 10 - (0.1)(40) + (0.3)(10) = 9.Second, calculate the average cost next year:AC2= 10 - (0.1)(50) + (0.3)(12) = 8.6.(Note: Cumulative output has increased from 40,000 to 50,000.) The average cost will decreasebecause of the learning effect.11. The short-run cost function of a company is given by the equation C = 190 + 53Q, where C is the total cost and Q is the total quantity of output, both measured in tens of thousands.a. What is the company’s fixed cost?When Q = 0, C = 190 (or $1,900,000). Therefore, fixed cost is equal to 190 (or $1,900,000).b. If the company produced 100,000 units of goods, what is its average variable cost?With 100,000 units, Q= 10. Variable cost is 53Q= (53)(10) = 530 (or $5,300,000). Averagevariable cost is TVCQ==$530$53.10c. What is its marginal cost per unit produced?With constant average variable cost, marginal cost is equal to average variable cost, $53.d. What is its average fixed cost?At Q = 10, average fixed cost is TFCQ==$190$1910.e. Suppose the company borrows money and expands its factory. Its fixed cost rises by $50,000,but its variable cost falls to $45,000 per 10,000 units. The cost of interest (I) also enters into the equation. Each one-point increase in the interest rate raises costs by $30,000. Write the new cost equation.Fixed cost changes from 190 to 195. Variable cost decreases from 53 to 45. Fixed cost alsoincludes interest charges: 3I . The cost equation isC = 195 + 45Q + 3I .*12. Suppose the long-run total cost function for an industry is given by the cubic equation TC = a + bQ + cQ 2 + dQ 3. Show (using calculus) that this total cost function is consistent with a U-shaped average cost curve for at least some values of a, b, c, d.To show that the cubic cost equation implies a U -shaped average cost curve, we use algebra,calculus, and economic reasoning to place sign restrictions on the parameters of the equation.These techniques are illustrated by the example below.First, if output is equal to zero, then TC = a , where a represents fixed costs. In the short run,fixed costs are positive, a > 0, but in the long run, where all inputs are variable a = 0. Therefore,we restrict a to be zero.Next, we know that average cost must be positive. Dividing TC by Q:AC = b + cQ + dQ 2.This equation is simply a quadratic function. When graphed, it has two basic shapes: a U shapeand a hill shape. We want the U shape, i.e., a curve with a minimum (minimum average cost),rather than a hill shape with a maximum.To the left of the minimum, the slope should be negative (downward sloping). At the minimum,the slope should be zero, and to the right of the minimum the slope should be positive (upwardsloping). The first derivative of the average cost curve with respect to Q must be equal to zero atthe minimum. For a U -shaped AC curve, the second derivative of the average cost curve must bepositive.The first derivative is c + 2dQ ; the second derivative is 2d . If the second derivative is to bepositive, then d > 0. If the first derivative is equal to zero, then solving for c as a function of Qand d yields: c = -2dQ . If d and Q are both positive, then c must be negative: c < 0.To restrict b , we know that at its minimum, average cost must be positive. The minimum occurswhen c + 2dQ = 0. We solve for Q as a function of c and d : Q c=->0. Next, substitutingthis value for Q into our expression for average cost, and simplifying the equation:2222⎪⎪⎭⎫ ⎝⎛-⎪⎪⎭⎫ ⎝⎛-++=++=d c d c d c b dQ cQ b AC , orAC b b b c d cd cd c d c d =-=-+=->+2222223362660. implying b c d >26. Because c 2and d > 0, b must be positive.In summary, for U -shaped long-run average cost curves, a must be zero, b and d must be positive, cmust be negative, and 4db > c 2. However, the conditions do not insure that marginal cost is positive.To insure that marginal cost has a U shape and that its minimum is positive, using the sameprocedure, i.e., solving for Q at minimum marginal cost -c d /,3 and substituting into theexpression for marginal cost b + 2cQ + 3dQ 2, we find that c 2 must be less than 3bd . Notice thatparameter values that satisfy this condition also satisfy 4db > c 2, but not the reverse.where a, b, and c are positive. Is this total cost function consistent with the presence of economies or diseconomies of scale? With economies or diseconomies of scope?There are two types of scale economies to consider: multiproduct economies of scale and product-specific returns to scale. From Section 7.5 we know that multiproduct economies of scalefor the two-product case, S H,S , are()()()()()S H S H MC S MC H S H TC S +=, , where MC H is the marginal cost of producing hardware and MC S is the marginal cost of producingsoftware. The product-specific returns to scale are:()()()()H H MC H S TC S H TC S ,0 , -= and ()()()()S S MC S H TC S H TC S 0, , -= where TC (0,S ) implies no hardware production and TC (H ,0) implies no software production. Weknow that the marginal cost of an input is the slope of the total cost with respect to that input.Since()(),S cH b aH bS H cS a TC -+=+-=we have MC H = a - cS and MC S = b - cH .Substituting these expressions into our formulas for S H,S , S H , and S S :()()cH b S cS a H cHS bS aH S S H -+--+=, or S aH bS cHS H S ,=+-+->1, because cHS > 0. Also, ()()cS a H bS cHS bS aH S H ---+=, or()()()()1=--=--=cS a cS a cS a H cHS aH S H and similarly ()().1=---+=cH b S aH cHS bS aH S S There are multiproduct economies of scale, S H,S > 1, but constant product-specific returns to scale,S H = S C = 1.Economies of scope exist if S C > 0, where (from equation (7.8) in the text):()()()()S H TC S H TC S TC H TC S c , , ,0 0, -+=, or, ()()S H TC cHS bS aH bS aH S c , -+-+=, or ().0, >=S H TC cHS S c Because cHS and TC are both positive, there are economies of scope.CHAPTER 8PROFIT MAXIMIZATION AND COMPETITIVE SUPPLYAs the title implies, this chapter covers two interrelated topics: a consideration of the behavioral incentives of the profit-maximizing firm and an examination of the interaction of these firms in a competitive market. The chapter begins with a discussion of whether firms maximize profits and ends with a discussion of the criteria for a competitive market, including an introduction to contestable markets. Exercises (1), (2), and (4) rely on data discussed in the text, while Exercises (3), (6), and (7) focus on the determination of the firm’s profit -maximizing quantity. Exercises (5), (8), and (9) consider the influence of taxes on firms’ output in a competitive market.S ections 8.2 through 8.4 derive the firm’s supply curve. Although total revenue is easily understood, you will need to show why average revenue may be represented by the demand curve. Demand and average revenue will be used interchangeably in Chapters 10 and 11. When presented with a problem involving the derivation of marginal revenue, some students will substitute Q , instead of P , in the expression for total revenue. This leads to revenue as a function of price. Stress that when they are given a demand curve in these applications they should first solve for price as a function of quantity. The origin of this confusion could lie in the popular notion that the firm determines the profit-maximizing price instead of the profit-maximizing quantity. Emphasize the importance of quantity, for example, when discussing why deviations from the profit-maximizing quantity lead to a decrease in profit (see Figure 8.3). Using the solutions to the exercises, emphasize that, for a linear demand curve, the slope of the marginal revenue curve is twice the slope of the demand curve.Other sources of confusion arise during analysis of firms’ supply curves. Stress that, as a primary rule, the firm should choose a quantity such that marginal revenue is equal to marginal cost. In this chapter, we can simplify this rule: for a firm facing a perfectly elastic demand curve, price is equal to marginal revenue. Stress that the rule for the competitive firm is a special case. Although some students will understand references to second-order conditions, expect to be asked why q 0 in Figure 8.3 is not profit maximizing, although MR = MC . Two additional points warrant careful explanation: 1) why the firm would remain in business if the firm sustains a loss in the short run, and 2) that maximizing profit is the same as minimizing loss.Although the summation of firm supply curves into a market supply curve is easy, the analysis of long-run competitive equilibrium is difficult. Show that long-run equilibrium relies on profit maximization by firms. Accompanying the rule that price must be greater than average variable cost in the short run, there is the assumption of free entry and exit. This leads to the statement that price must equal long-run average cost, LAC, as no firm may make an economic profit. The rule that price must equal long-run marginal cost, LMC , is the second equilibrium condition. Therefore, because LAC = LMC at minimum LAC , price is equal to minimum LAC in the long-run equilibrium. This result will be reconsidered in Chapter 12 in the discussion of equilibrium for a monopolistically competitive firm. When discussing the attainment of equilibrium in constant, increasing, and。

微观经济学练习与思考的参考答案第8章寡头市场与博弈论初步

第8章寡头市场与博弈论初步【练习及思考】参考答案要点1. 填空题(1)从博弈类型和决策变量的角度，我们可对寡头模型进行分类，经典寡头模型包括：古诺模型、伯川德模型、斯塔克尔伯格模型、价格领导模型、卡特尔模型等。

(2)伯川德模型假定两个寡头厂商通过选择价格而展开竞争，相互竞价的结果将使均衡价格等于边际成本，产量等于完全竞争产量，厂商的经济利润为零，此结果被称为伯川德悖论。

(3)博弈论是研究决策主体的行为发生直接相互作用时候的决策以及这种决策的均衡问题的理论。

博弈的最基本要素包括：参与人、策略空间和支付，它们往往通过标准式进行表述。

2. 判断题（下列判断正确的在括号内打√，不正确的打 ×）(1)（×）古诺模型假定，行业中只有两个厂商，他们的边际成本既定，且每个厂商都假定另一个厂商的产出数量不变。

(2)（×）在伯川德寡头模型中，厂商的均衡价格大于边际成本。

(3)（×）当寡头厂商在竞争中勾结起来时，寡头市场的运行便相当于一个完全竞争市场。

(4)（×）利润最大化的卡特尔达到了稳定的均衡，因为在它控制下的任何一个厂商不打算做任何变动。

(5)（√）在斯塔克尔伯格模型中，领导企业的利润将大于古诺均衡利润。

(6)（×）寡头市场形成的必要条件之一是产品具有差别。

3. 选择题1）厂商之间关系最密切的市场是（ B ）。

A.完全竞争市场B.寡头垄断市场C.垄断竞争市场D.完全垄断市场2）根据古诺模型，在双头垄断条件下，厂商的产量是市场容量的（ A ）。

A.1/3倍B.2/3倍C.1倍D.不能确定3）寡头垄断就是（ D ）。

A.很多厂商生产不同的产品B.少数厂商生产不同的产品C.很多厂商生产同类的产品D.以上都不对4）博弈当中最基本的，揭示博弈最终结局的均衡是（ B ）。

A. 囚徒困境B. 纳什均衡C. 瓦尔拉斯均衡D. 古诺均衡5）寡头垄断市场的特点是（ABCDE ）。

微观经济学第三版习题答案

第1章习题答案1.单一选择答案：1（C）2 (D）3 （D）4 （B）5 （A）2。

判断正误答案： 1（×）2 （×）3 （×）4 （√）5（×）3。

分析题答案1).为什么说稀缺性的存在与选择的必要引起了经济学的产生？由于资源的稀缺,人类的需求是无限的,这对矛盾使得人类在利用资源的时候不能随心所欲，要进行选择--把稀缺资源用在何种用途上才能满足人类的最大需求？经济系统中的个人、组织和政府时刻面临着选择，选择怎样的用途，进行怎样的配置使得稀缺资源满足个人、组织和社会最大的需求？经济学正是研究有关选择的原则的学科，这是应人类选择的需要而产生的.2）。

为什么微观经济学的研究对象是经济资源的合理配置和充分利用问题?正是因为经济学是研究选择的原则的学科，而经济系统必须做出的基本选择是：生产什么、生产多少？怎样生产？为谁生产?人们需要的产品种类繁多和无限性,使得关于生产什么、生产多少的合理选择的难度大大提高。

怎样生产？用什么样的方法来生产这么多的产量与劳务，是对生产要素投入组合、生产规模和生产技术的选择。

为谁生产?生产出来的产量和劳务用什么样方式在参与生产的各部分人之间分配。

这是一个重要选择.综上，假定生产什么和生产多少一定，则所需多少资源投入等技术问题就决定下来，资源配置就被决定。

如果怎样生产一定,如何投入资源的选择就被决定。

为谁生产一定，资源的配置与流向就被决定。

所以说前两种选择是资源配置在产出方面的选择，后一种选择是资源配置在投入方面的选择。

所以说，经济学的研究对象是资源的合理配置和充分利用问题。

3）。

微观经济学的基本问题和研究内容有哪些？微观经济学的基本问题是：生产什么、生产多少?怎样生产？为谁生产？围绕这一基本问题研究的主要内容有：(1)均衡价格理论。

也称价格理论，研究商品的价格如何决定，以及价格如何调节整个经济的运行。

均衡价格理论是微观经济学的核心.象一条红线贯穿于微观经济学的始终。

习题--《微观经济学》第七章：不完全竞争--高鸿业,人教版

第七章：不完全竞争的市场一、名词解释完全垄断、自然垄断、价格歧视、一级价格歧视、二级价格歧视、三级价格歧视、垄断竞争、寡头垄断、古诺模型、斯塔克伯格模型、斯威齐模型。

二、单项选择题1、下列不能成为进入一个行业的壁垒的是（）。

A．垄断利润B．立法C．专利权D．资源控制2、下列那一个不是垄断竞争的特征（）。

A、厂商数目很少B、进入该行业容易C、存在产品差别D、厂商忽略竞争对手的反应3、一个市场上只有一个厂商，生产一种没有替代品的产品，这样的市场结构被称为（）。

A、垄断竞争B、完全垄断C、寡头垄断D、完全竞争4、垄断厂商面临的需求曲线是（）。

A、向下倾斜的B、向上倾斜的C、垂直的D、水平的5、垄断厂商拥有控制市场的权力，这意味着（）。

A．垄断厂商面对一条向下倾斜的需求曲线B．如果他的产品增加一个单位，则全部产品的销售价格必须降低C．垄断厂商的边际收益曲线低于其需求曲线D．以上都对6、垄断条件下，当商品的需求的价格弹性小于1时，厂商的边际收益（）。

A.大于0；B.大于1；C.小于0；D.小于1。

7、垄断利润属于( )。

A.经济成本；B.正常利润；C.经济利润；D.隐成本。

8、当一个行业由竞争演变成垄断行业时，则（）。

A．垄断市场的价格等于竞争市场的价格；B．垄断市场的价格大于竞争市场的价格；C．垄断市场的价格小于竞争市场的价格；D．垄断价格具有任意性。

9、在垄断厂商的长短期均衡产量上可以有（）。

A．P＞LAC；B．P＜LAC；C．P等于最小的LAC；D．P等于最小的LMC。

10、一个垄断厂商在长期中一直获得经济利润，那么（）。

A．该厂商的生产比竞争性市场的厂商更有效率B．其他厂商无法进入该行业与其竞争C．政府和垄断厂商之间必定串谋来维持一个高价格D．垄断厂商的需求曲线缺乏弹性，从而使得其获得更多的收益11、完全垄断厂商达于长期均衡的条件是：（）。

A、MR=MCB、MR=SMC=LMCC、MR=SMC=LMC=SACD、MR=SMC=SAC=LAC12、要有效地实行差别定价，下列那一条以外都是必需具备的条件：（）。