曼昆 经济学原理：宏观经济学 习题答案(第五版)
曼昆 经济学原理 第五版 答案 2
SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Economics is like a science because economists devise theories, collect data, and analyze the datain an attempt to verify or refute their theories. In other words, economics is based on thescientific method.Figure 1 shows the production possibilities frontier for a society that produces food and clothing.Point A is an efficient point (on the frontier), point B is an inefficient point (inside the frontier), and point C is an infeasible point (outside the frontier).Figure 1The effects of a drought are shown in Figure 2. The drought reduces the amount of food that can be produced, shifting the production possibilities frontier inward.15Figure 2Microeconomics is the study of how households and firms make decisions and how they interact in markets. Macroeconomics is the study of economy-wide phenomena, including inflation,unemployment, and economic growth.2. An example of a positive statement is “higher taxes discourage work effort” (many other answersare possible). That’s a positive statement because it describes the effects of higher taxes,describing the world as it is. An example of a normative statement is “the government shouldreduce tax rates.” That is a normative statement because it’s a claim about how the world should be.Parts of the government that regularly rely on advice from economists are the TreasuryDepartment in designing tax policy, the Department of Labor in analyzing data on the employment situation, the Justice Department in enforcing the nation’s antitrust laws, the Congressional Budget Office in evaluating policy proposals, and the Federal Reserve in analyzing economic developments (many other answers are possible).3. Economic advisers to the president might disagree about a question of policy because of differingscientific judgments or differences in values.Questions for Review1. Economics is like a science because economists use the scientific method. They devise theories,collect data, and then analyze these data in an attempt to verify or refute their theories about how the world works. Economists use theory and observation like other scientists, but they are limited in their ability to run controlled experiments. Instead, they must rely on natural experiments.2. Economists make assumptions to simplify problems without substantially affecting the answer.Assumptions can make the world easier to understand.3. An economic model cannot describe reality exactly because it would be too complicated tounderstand. A model is a simplification that allows the economist to see what is truly important.4. Figure 3 shows a production possibilities frontier between milk and cookies (PPF1). If a diseasekills half of the economy's cow population, less milk production is possible, so the PPF shifts inward (PPF2). Note that if the economy produces all cookies, so it doesn't need any cows, thenproduction is unaffected. But if the economy produces any milk at all, then there will be lessproduction possible after the disease hits.Figure 35. The idea of efficiency is that an outcome is efficient if the economy is getting all it can from thescarce resources it has available. In terms of the production possibilities frontier, an efficientpoint is a point on the frontier, such as point A in Figure 4. A point inside the frontier, such aspoint B, is inefficient since more of one good could be produced without reducing the production of another good.Figure 46. The two subfields in economics are microeconomics and macroeconomics. Microeconomics is thestudy of how households and firms make decisions and how they interact in specific markets.Macroeconomics is the study of economy-wide phenomena.7. Positive statements are descriptive and make a claim about how the world is, while normativestatements are prescriptive and make a claim about how the world ought to be. Here is an example.Positive: A rapid growth rate of money is the cause of inflation. Normative: The government should keep the growth rate of money low.8. The Council of Economic Advisers is a group of economists who consult with the president of theUnited States about economic matters. The Council consists of three members and a staff ofseveral dozen economists. It writes the annual Economic Report of the President.9. Economists sometimes offer conflicting advice to policymakers for two reasons:(1) economists may disagree about the validity of alternative positive theories about how theworld works; and (2) economists may have different values and, therefore, different normativeviews about what public policy should try to accomplish.Problems and Applicat ions1. Many answers are possible.2. a. Steel is a fairly uniform commodity, though some firms produce steel of inferior quality.b. Novels are each unique, so they are quite distinguishable.c. Wheat produced by one farmer is completely indistinguishable from wheat produced byanother.d. Fast food is more distinguishable than steel or wheat, but certainly not as much as novels.3. See Figure 5; the four transactions are shown.Figure 54. a. Figure 6 shows a production possibilities frontier between guns and butter. It is bowedout because when most of the economy’s resour ces are being used to produce butter, thefrontier is steep and when most of the economy’s resources are being used to produceguns, the frontier is very flat. When the economy is producing a lot of guns, workers andmachines best suited to making butter are being used to make guns, so each unit of gunsgiven up yields a large increase in the production of butter. Thus, the productionpossibilities frontier is flat. When the economy is producing a lot of butter, workers andmachines best suited to making guns are being used to make butter, so each unit of gunsgiven up yields a small increase in the production of butter. Thus, the productionpossibilities frontier is steep.b. Point A is impossible for the economy to achieve; it is outside the production possibilitiesfrontier. Point B is feasible but inefficient because it’s inside the production possibilitiesfrontier.Figure 6c. The Hawks might choose a point like H, with many guns and not much butter. The Dovesmight choose a point like D, with a lot of butter and few guns.d. If both Hawks and Doves reduced their desired quantity of guns by the same amount, theHawks would get a bigger peace dividend because the production possibilities frontier ismuch steeper at point H than at point D. As a result, the reduction of a given number ofguns, starting at point H, leads to a much larger increase in the quantity of butter producedthan when starting at point D.5. See Figure 7. The shape and position of the frontier depend on how costly i t is to maintain a cleanenvironment the productivity of the environmental industry. Gains in environmental productivity, such as the development of a no-emission auto engine, lead to shifts of the production-possibilities frontier, like the shift from PPF1 to PPF2 shown in the figure.Figure 76. a. A family's decision about how much income to save is microeconomics.b. The effect of government regulations on auto emissions is microeconomics.c. The impact of higher saving on economic growth is macroeconomics.d. A firm's decision about how many workers to hire is microeconomics.e. The relationship between the inflation rate and changes in the quantity of money ismacroeconomics.7. a. The statement that society faces a short-run tradeoff between inflation and unemploymentis a positive statement. It deals with how the economy is, not how it should be. Sinceeconomists have examined data and found that there is a short-run negative relationshipbetween inflation and unemployment, the statement is a fact, thus it is a positivestatement.b. The statement that a reduction in the rate of growth of money will reduce the rate ofinflation is a positive statement. Economists have found that money growth and inflationare very closely related. The statement thus tells how the world is, and so it is a positivestatement.c. The statement that the Federal Reserve should reduce the rate of growth of money is anormative statement. It states an opinion about something that should be done, not howthe world is.d. The statement that society ought to require welfare recipients to look for jobs is anormative statement. It doesn't state a fact about how the world is. Instead, it is astatement of how the world should be and is thus a normative statement.e. The statement that lower tax rates encourage more work and more saving is a positivestatement. Economists have studied the relationship between tax rates and work, as wellas the relationship between tax rates and saving. They have found a negati verelationship in both cases. So the statement reflects how the world is, and is thus apositive statement.8. Two of the statements in Table 2 are clearly normative. They are: "5. If the federal budget isto be balanced, it should be done over the business cycle rather than yearly" and "9. Thegovernment should restructure the welfare system along the lines of a 'negative income tax.'"Both are suggestions of changes that should be made, rather than statements of fact, so they are clearly normative statements.The other statements in the table are positive. All the statements concern how the world is, nothow the world should be. Note that in all cases, even though they are statements of fact, fewer than 100 percent of economists agree with them. You could say that positive statements arestatements of fact about how the world is, but not everyone agrees about what the facts are.9. As the president, you'd be interested in both the positive and normative views of economists, butyou'd probably be most interested in their positive views. Economists are on your staff to provide their expertise about how the economy works. They know many facts about the economy and the interaction of different sectors. So you would be most likely to call on them about questions of fact positive analysis. Since you are the president, you are the one who has to make thenormative statements as to what should be done, with an eye to the political consequences. The normative statements made by economists represent their own views, not necessarily your views or the electorate’s views.10. There are many possible answers.11. As of this writing, the chairman of the Federal Reserve is Alan Greenspan, the chair of the Councilof Economic Advisers is R. Glen Hubbard, and the secretary of the treasury is Paul H. O’Neill.12. As time goes on, you might expect economists to disagree less about public policy because they willhave opportunities to observe different policies that are put into place. As new policies are tried, their results will become known, and they can be evaluated better. It's likely that thedisagreement about them will be reduced after they've been tried in practice. For example, many economists thought that wage and price controls would be a good idea for keeping inflation under control, while others thought it was a bad idea. But when the controls were tried in the early1970s, the results were disastrous. The controls interfered with the invisible hand of themarketplace and shortages developed in many markets. As a result, most economists are now convinced that wage and price controls are a bad idea for controlling inflation.But it is unlikely that the differences between economists will ever be completely eliminated.Economists differ on too many aspects of how the world works. Plus, even as some policies get tried out and are either accepted or rejected, creative economists keep coming up with new ideas.。
曼昆宏观经济学原理第五版chap31to32课后习题答案(中文)
未预期的通货膨胀降低了政府债券的投资价值。
11．解释一种与未预期到的通货膨胀相关而与预期到的通货膨胀无关的害处。
然后解释一种既与预期到的通货膨胀相关，又与未预期到的通货膨胀相关的害处。
答：未预期到的通货膨胀会以一种既与才能无关又与需要无关的方式在人们中重新分配财富，这种再分配的发生最可能发生在以固定价格来计量的贷款中。
它会以损害债权人的代价而减轻债务人的偿还负担。
无论通货膨胀是否预期到了，它都会扭曲价格信号、影响货币的正常使用，使现金的名义利率从零变为负数。
12．说明以下陈述正确、错误，还是不确定。
A．“通货膨胀伤害了债务人的利益而帮助了债权人，因为债务人必须支付更高的利率。
”答：这种陈述不确定。
如果实际通货膨胀率高于预期通货膨胀率，则帮助了债务人，因为实际利率低于预期名义利率。
如果实际通货膨胀率低于预期通货膨胀率，则帮助了债权人，因为实际利率高于预期名义利率。
B．“如果价格以一种使物价总水平不变的方式变动，那么，没有一个人的状况会变得更好或更坏。
”答一：这种陈述正确。
答二：这种陈述错误。
因为即使物价总水平保持不变，但相对价格的变动也会使一些人的福利变好，而使另一些人的福利变坏。
C．“通货膨胀并没有降低大多数工人的购买力。
”答一：这种陈述错误。
因为通货膨胀降低了大多数工人的购买力。
大多数工人的工资由于长期劳资合约的限制不能迅速调整，因此工人的工资增长慢于通货膨胀的攀升。
答二：这种陈述正确。
因为大多数工人的工资根据通货膨胀率的变动而进行合理的调整。
第十一篇开放经济宏观经济学第三十一章开放经济宏观经济学：基本概念复习题1．定义净出口与资本净流出。
解释它们如何相关以及为什么相关。
答：净出口是一国的出口值减去进口值，又称贸易余额。
资本净流出是指本国居民购买的外国资产减去外国人购买的国内资产。
一个开放经济以两种方式与世界其他经济相互交易——在世界物品与劳务市场上和世界金融市场上。
净出口和资本净流出分别衡量了这些市场上的不平衡类型。
宏观经济学第五版课后习题答案
P38013.假定一国有下列国民收入统计资料：单位：亿美元国内生产总值 4 800800总投资净投资3003 000消费960政府购买 30政府预算盈余 试计算：(1) 国内生产净值；(2) 净出口；(3) 政府税收减去转移支付后的收入；(4) 个人可支配收入；(5) 个人储蓄。
解答：(1) 国内生产净值＝国内生产总值－资本消耗补偿，而资本消耗补偿即折旧等于总投资减净投资后的余额，即500＝800－300，因此国内生产净值＝4 800－500＝4 300(亿美元)。
(2) 从GDP＝c＋i＋g＋nx中可知nx＝GDP－c－i－g，因此，净出口nx＝4 800－3 000－800－960＝40(亿美元)。
(3) 用BS代表政府预算盈余，T代表净税收即政府税收减去转移支付后的收入，则有BS＝T－g，从而有T＝BS＋g＝30＋960＝990(亿美元)。
(4) 个人可支配收入本来是个人收入减去个人所得税后的余额，本题条件中没有说明间接税、公司利润、社会保险税等因素，因此，可从国民生产净值中直接得到个人可支配收入，即y d＝NNP－T＝4 300－990＝3 310(亿美元)。
(5) 个人储蓄S＝y d－c＝3 310－3 000＝310(亿美元)。
14.假定国内生产总值是5 000，个人可支配收入是4 100，政府预算赤字是200，消费是3 800，贸易赤字是100(单位都是亿元)。
试计算：(1) 储蓄；(2) 投资；(3) 政府支出。
解答：(1) 用s代表储蓄(即私人储蓄s p)，用y d代表个人可支配收入，则 s＝y d－c＝4 100－3 800＝300(亿元)(2) 用i代表投资，用s p、 s g、 s r分别代表私人部门、政府部门和国外部门的储蓄，则s g＝t－g＝BS，在这里，t代表政府税收收入，g代表政府支出，BS代表预算盈余，在本题中，s g ＝BS＝－200。
s r表示外国部门的储蓄，即外国的出口减去进口，对本国来说，则是进口减出口，在本题中为100，因此投资为 i＝s p＋ s g＋ s r＝300＋(－200)＋100＝200(亿元)(3) 从GDP＝c＋i＋g＋(x－m)中可知，政府支出 g＝5 000－3 800－200－(－100)＝1 100(亿元)第十三章 简单国民收入决定理论1.在两部门经济中，均衡发生于( )之时。
曼昆经济学原理宏观第五版答案
曼昆经济学原理宏观第五版答案【篇一：经济学原理曼昆(宏观部分答案)】>第二十三章一国收入的衡量复习题 1 ．解释为什么一个经济的收入必定等于其支出? 答：对一个整体经济而言，收入必定等于支出。
因为每一次交易都有两方：买者和卖者。
一个买者的1 美元支出是另一个卖者的1 美元收入。
因此，交易对经济的收入和支出作出了相同的贡献。
由于gdp 既衡量总收入 135 又衡量总支出，因而无论作为总收入来衡量还是作为总支出来衡量，gdp 都相等.2 ．生产一辆经济型轿车或生产一辆豪华型轿车，哪一个对gdp 的贡献更大？为什么? 答：生产一辆豪华型轿车对gdp 的贡献大。
因为gdp 是在某一既定时期一个国家内生产的所有最终物品与劳务的市场价值。
由于市场价格衡量人们愿意为各种不同物品支付的量，所以市场价格反映了这些物品的市场价值。
由于一辆豪华型轿车的市场价格高于一辆经济型轿车的市场价格，所以一辆豪华型轿车的市场价值高于一辆经济型轿车的市场价值，因而生产一辆豪华型轿车对gdp 的贡献更大.3 ．农民以2 美元的价格把小麦卖给面包师。
面包师用小麦制成面包，以3 美元的价格出售。
这些交易对 gdp 的贡献是多少呢? 答：对gdp 的贡献是3 美元。
gdp 只包括最终物品的价值，因为中间物品的价值已经包括在最终物品的价格中了.4 ．许多年以前，peggy 为了收集唱片而花了500 美元。
今天她在旧货销售中把她收集的物品卖了100 美元.这种销售如何影响现期gdp? 答：现期gdp 只包括现期生产的物品与劳务，不包括涉及过去生产的东西的交易。
因而这种销售不影响现期gdp.5 ．列出gdp 的四个组成部分。
各举一个例子.答：gdp 等于消费(c)+投资(i)+政府购买(g)+净出口(nx) 消费是家庭用于物品与劳务的支出，如汤姆一家人在麦当劳吃午餐.投资是资本设备、存货、新住房和建筑物的购买，如通用汽车公司建立一个汽车厂.政府购买包括地方政府、州政府和联邦政府用于物品与劳务的支出，如海军购买了一艘潜艇.净出口等于外国人购买国内生产的物品(出口)减国内购买的外国物品(进口)。
曼昆 经济学原理 第五版 答案 1
SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. The four principles of economic decisionmaking are: (1) people face tradeoffs; (2) the cost ofsomething is what you give up to get it; (3) rational people think at the margin; and (4) peoplerespond to incentives. People face tradeoffs because to get one thing that they like, they usually have to give up another thing that they like. The cost of something is what you give up to get it, not just in terms of monetary costs but all opportunity costs. Rational people think at the margin by taking an action if and only if the marginal benefits exceed the marginal costs. People respond to incentives because as they compare benefits to costs, a change in incentives may cause theirbehavior to change.2. The three principles concerning economic interactions are: (1) trade can make everyone betteroff; (2) markets are usually a good way to organize economic activity; and (3) governments can sometimes improve market outcomes. Trade can make everyone better off because it allowscountries to specialize in what they do best and to enjoy a wider variety of goods and services.Markets are usually a good way to organize economic activity because the invisible hand leadsmarkets to desirable outcomes. Governments can so metimes improve market outcomes because sometimes markets fail to allocate resources efficiently because of an externality or market power.3. The three principles that describe how the economy as a whole works are: (1) a country’sstandard of living depends on its ability to produce goods and services; (2) prices rise when thegovernment prints too much money; and (3) society faces a short-run tradeoff between inflation and unemployment. A country’s standard of living depends on its ability to produce g oods andservices, which in turn depends on its productivity, which is a function of the education of workers and the access workers have to the necessary tools and technology. Prices rise when thegovernment prints too much money because more money in circulation reduces the value of money, causing inflation. Society faces a short-run tradeoff between inflation and unemployment that is only temporary and policymakers have some ability to exploit this relationship using various policy instruments.Questions for Review1. Examples of tradeoffs include time tradeoffs (such as studying one subject over another, orstudying at all compared to engaging in social activities) and spending tradeoffs (such as whether to use your last ten dollars on pizza or on a study guide for that tough economics course).2. The opportunity cost of seeing a movie includes the monetary cost of admission plus the time costof going to the theater and attending the show. The time cost depends on what else you might do with that time; if it's staying home and watching TV, the time cost may be small, but if it's working an extra three hours at your job, the time cost is the money you could have earned.3. The marginal benefit of a glass of water depends on your circumstances. If you've just run amarathon, or you've been walking in the desert sun for three hours, the marginal benefit is veryhigh. But if you've been drinking a lot of liquids recently, the marginal benefit is quite low. The point is that even the necessities of life, like water, don't always have large marginal benefits.4. Policymakers need to think about incentives so they can understand how people will respond to thepolicies they put in place. The text's example of seat belts shows that policy actions can ha vequite unintended consequences. If incentives matter a lot, they may lead to a very different type1of policy; for example, some economists have suggested putting knives in steering columns so that people will drive much more carefully! While this suggestion is silly, it highlights the importance of incentives.5. Trade among countries isn't a game with some losers and some winners because trade can makeeveryone better off. By allowing specialization, trade between people and trade betweencountries can improve everyone's welfare.6. The "invisible hand" of the marketplace represents the idea that even though individuals and firmsare all acting in their own self-interest, prices and the marketplace guide them to do what is good for society as a whole.7. The two main causes of market failure are externalities and market power. An externality is theimpact of one person’s actions on the well-being of a bystander, such as from pollution or thecreation of knowledge. Market power refers to the ability of a single person (or small group of people) to unduly influence market prices, such as in a town with only one well or only one cable television company. In addition, a market economy also leads to an unequal distribution ofincome.8. Productivity is important because a country's standard of living depends on its ability to producegoods and services. The greater a country's productivity (the amount of goods and servicesproduced from each hour of a worker's time), the greater will be its standard of living.9. Inflation is an increase in the overall level of prices in the economy. Inflation is caused byincreases in the quantity of a nation's money.10. Inflation and unemployment are negatively related in the short run. Reducing inflation entailscosts to society in the form of higher unemployment in the short run.Problems and Applicat ions1. a. A family deciding whether to buy a new car faces a tradeoff between the cost of the carand other things they might want to buy. For example, buyi ng the car might mean theymust give up going on vacation for the next two years. So the real cost of the car is thefamily's opportunity cost in terms of what they must give up.b. For a member of Congress deciding whether to increase spending on national parks, thetradeoff is between parks and other spending items or tax cuts. If more money goes intothe park system, that may mean less spending on national defense or on the police force.Or, instead of spending more money on the park system, taxes could be reduced.c. When a company president decides whether to open a new factory, the decision is basedon whether the new factory will increase the firm's profits compared to other alternatives.For example, the company could upgrade existing equipment or expand existing factories.The bottom line is: Which method of expanding production will increase profit the most?d. In deciding how much to prepare for class, a professor faces a tradeoff between the valueof improving the quality of the lecture compared to other things she could do with her time,such as working on additional research.2. When the benefits of something are psychological, such as going on a vacation, it isn't easy tocompare benefits to costs to determine if it's worth doing. But there are two ways to think aboutthe benefits. One is to compare the vacation with what you would do in its place. If you didn't go on vacation, would you buy something like a new set of golf clubs? Then you can decide ifyou'd rather have the new clubs or the vacation. A second way is to think about how much work you had to do to earn the money to pay for the vacation; then you can decide if the psychological benefits of the vacation were worth the psychological cost of working.3. If you are thinking of going skiing instead of working at your part-time job, the cost of skiingincludes its monetary and time costs, which includes the opportunity cost of the wages you aregiving up by not working. If the choice is between skiing and going to the librar y to study, then the cost of skiing is its monetary and time costs including the cost to you of getting a lower grade in your course.4. If you spend $100 now instead of saving it for a year and earning 5 percent interest, you are givingup the opportunity to spend $105 a year from now. The idea that money has a time value is the basis for the field of finance, the subfield of economics that has to do with prices of financialinstruments like stocks and bonds.5. The fact that you've already sunk $5 million isn't relevant to your decision anymore, since thatmoney is gone. What matters now is the chance to earn profits at the margin. If you spendanother $1 million and can generate sales of $3 million, you'll earn $2 million in marginal profit, so you should do so. You are right to think that the project has lost a total of $3 million ($6 million in costs and only $3 million in revenue) and you shouldn't have started it. That's true, but if youdon't spend the additional $1 million, you won't have any sales and your losses will be $5 million.So what matters is not the total profit, but the profit you can earn at the margin. In fact, you'd pay up to $3 million to complete development; any more than that, and you won't be increasing profit at the margin.6. Harry suggests looking at whether productivity would rise or fall. Productivity is certainlyimportant, since the more productive workers are, the lower the cost per gallon of potion. Ron wants to look at average cost. But both Harry and Ron are missing the other side of theequation−revenue. A firm wants to maximize its profits, so it needs to examine both costs and revenues. Thus, Hermione is right−it’s best to examine whether the extra revenue would exceed the extra costs. Hermione is the only one who is thinking at the margin.7. a. The provision of Social Security benefits lowers an individual’s incentive to save forretirement. The benefits provide some level of income to the individual when he or sheretires. This means that the individual is not entirely dependent on savings to supportconsumption through the years in retirement.b. Since a person gets fewer after-tax Social Security benefits the greater is his or herearnings, there is an incentive not to work (or not work as much) after age 65. The moreyou work, the lower your after-tax Social Security benefits will be. Thus the taxation ofSocial Security benefits discourages work effort after age 65.8. a. When welfare recipients who are able to work have their benefits cut off after two years,they have greater incentive to find jobs than if their benefits were to last forever.b. The loss of benefits means that someone who can't find a job will get no income at all, sothe distribution of income will become less equal. But the economy will be more efficient,since welfare recipients have a greater incentive to find jobs. Thus the change in the lawis one that increases efficiency but reduces equity.9. By specializing in each task, you and your roommate can finish the chores more quickly. If youdivided each task equally, it would take you more time to cook than it would take your roommate, and it would take him more time to clean than it would take you. By specializing, you reduce the total time spent on chores.Similarly, countries can specialize and trade, making both better off. For example, suppose ittakes Spanish workers less time to make clothes than French workers, and French workers canmake wine more efficiently than Spanish workers. Then Spain and France can both benefit ifSpanish workers produce all the clothes and French workers produce all the wine, and theyexchange some wine for some clothes.10. a. Being a central planner is tough! To produce the right number of CDs by the right artistsand deliver them to the right people requires an enormous amount of information. Youneed to know about production techniques and costs in the CD industry. You need toknow each person's musical tastes and which artists they want to hear. If you make thewrong decisions, you'll be producing too many CDs by artists that people don't want tohear, and not enough by others.b. Your decisions about how many CDs to produce carry over to other decisions. You haveto make the right number of CD players for people to use. If you make too many CDs andnot enough cassette tapes, people with cassette players will be stuck with CDs they can'tplay. The probability of making mistakes is very high. You will also be faced with toughchoices about the music industry compared to other parts of the economy. If youproduce more sports equipment, you'll have fewer resources for making CDs. So alldecisions about the economy influence your decisions about CD production.11. a. Efficiency: The market failure comes from the monopol y by the cable TV firm.b. Equityc. Efficiency: An externality arises because secondhand smoke harms nonsmokers.d. Efficiency: The market failure occurs because of Standard Oil's monopoly power.e. Equityf. Efficiency: There is an externality because of accidents caused by drunk drivers.12. a. If everyone were guaranteed the best health care possible, much more of our nation'soutput would be devoted to medical care than is now the case. Would that be efficient?If you think that currently doctors form a monopoly and restrict health care to keep theirincomes high, you might think efficiency would increase by providing more health care.But more likely, if the government mandated increased spending on health care, theeconomy would be less efficient because it would give people more health care than theywould choose to pay for. From the point of view of equity, if poor people are less likely tohave adequate health care, providing more health care would represent an improvement.Each person would have a more even slice of the economic pie, though the pie wouldconsist of more health care and less of other goods.b. When workers are laid off, equity considerations argue for the unemployment benefitssystem to provide them with some income until they can find new jobs. After all, no oneplans to be laid off, so unemployment benefits are a form of insurance. But there’s anefficiency problem why work if you can get income for doing nothing? The economyisn’t operating efficiently if p eople remain unemployed for a long time, and unemploymentbenefits encourage unemployment. Thus, there’s a tradeoff between equity andefficiency. The more generous are unemployment benefits, the less income is lost by anunemployed person, but the more that person is encouraged to remain unemployed. Sogreater equity reduces efficiency.13. Since average income in the United States has roughly doubled every 35 years, we are likely tohave a better standard of living than our parents, and a much better standard of living than our grandparents. This is mainly the result of increased productivity, so that an hour of workproduces more goods and services than it used to. Thus incomes have continuously risen over time, as has the standard of living.14. If Americans save more and it leads to more spending on factories, there will be an increase inproduction and productivity, since the same number of workers will have more equipment to work with. The benefits from higher productivity will go to both the workers, who will get paid more since they're producing more, and the factory owners, who will get a return on their investments.There is no such thing as a free lunch, however, because when people save more, they are giving up spending. They get higher incomes at the cost of buying fewer goods.15. a. If people have more money, they are probably going to spend more on goods and services.b. If prices are sticky, and people spend more on goods and services, then output mayincrease, as producers increase output to meet the higher demand rather than raisingprices.c. If prices can adjust, then the higher spending of consumers will be matched with increasedprices and output won't rise.16. To make an intelligent decision about whether to reduce inflation, a policymaker would need toknow what causes inflation and unemployment, as well as what determines the tradeoff between them. Any attempt to reduce inflation will likely lead to higher unemployment in the short run. A policymaker thus faces a tradeoff between the benefits of lower inflation compared to the cost of higher unemployment.。
(微观 宏观全)曼昆《经济学原理》(第五版)课后习题答案-中文版
曼昆《经济学原理》（第五版）习题解答目录第一章经济学十大原理 (1)第二章像经济学家一样思考 (7)第三章相互依存性与贸易的好处 (14)第四章供给与需求的市场力量 (22)第五章弹性及其应用 (31)第六章供给、需求与政府政策 (41)第七章消费者、生产者与市场效率 (50)第八章应用：赋税的代价 (58)第九章应用：国际贸易 (65)第十章外部性 (75)第十一章公共物品和公共资源 (84)第十二章税制的设计 (91)第十三章生产成本 (99)第十四章竞争市场上的企业 (109)第十五章垄断 (121)第十六章垄断竞争 (135)第十七章寡头 (143)第十八章生产要素市场 (153)第十九章收入与歧视 (162)第二十章收入不平等与贫困 (169)第二十一章消费者选择理论 (177)第二十二章微观经济学前沿 (187)第二十三章一国收入的衡量 (195)第二十四章生活费用的衡量 (204)第二十五章生产与增长 (210)第二十六章储蓄、投资和金融体系 (214)第二十七章基本金融工具 (221)第二十八章失业 (226)第一篇导言第一章经济学十大原理复习题1．列举三个你在生活中面临的重要权衡取舍的例子。
答：①大学毕业后，面临着是否继续深造的选择，选择继续上学攻读研究生学位，就意味着在今后三年中放弃参加工作、赚工资和积累社会经验的机会；②在学习内容上也面临着很重要的权衡取舍，如果学习《经济学》，就要减少学习英语或其他专业课的时间；③对于不多的生活费的分配同样面临权衡取舍，要多买书，就要减少在吃饭、买衣服等其他方面的开支。
2．看一场电影的机会成本是什么?答：看一场电影的机会成本是在看电影的时间里做其他事情所能获得的最大收益，例如：看书、打零工。
3．水是生活必需的。
一杯水的边际利益是大还是小呢?答：这要看这杯水是在什么样的情况下喝，如果这是一个人五分钟内喝下的第五杯水，那么他的边际利益很小，有可能为负；如果这是一个极度干渴的人喝下的第一杯水，那么他的边际利益将会极大。
曼昆经济学原理第五版标准答案宏观
曼昆经济学原理第五版答案宏观【篇一:经济学原理曼昆(宏观部分答案)】>第二十三章一国收入的衡量复习题 1.解释为什么一个经济的收入必定等于其支出? 答：对一个整体经济而言，收入必定等于支出。
因为每一次交易都有两方:买者和卖者。
一个买者的1 美元支出是另一个卖者的1 美元收入。
因此，交易对经济的收入和支出作出了相同的贡献。
由于gｄp 既衡量总收入 13５又衡量总支出,因而无论作为总收入来衡量还是作为总支出来衡量,gdｐ都相等.2 ．生产一辆经济型轿车或生产一辆豪华型轿车,哪一个对gdp的贡献更大？为什么? 答:生产一辆豪华型轿车对gdp的贡献大。
因为gｄｐ是在某一既定时期一个国家内生产的所有最终物品与劳务的市场价值。
由于市场价格衡量人们愿意为各种不同物品支付的量,所以市场价格反映了这些物品的市场价值。
由于一辆豪华型轿车的市场价格高于一辆经济型轿车的市场价格,所以一辆豪华型轿车的市场价值高于一辆经济型轿车的市场价值，因而生产一辆豪华型轿车对gdp 的贡献更大．3 ．农民以２美元的价格把小麦卖给面包师。
面包师用小麦制成面包,以3美元的价格出售。
这些交易对ｇdｐ的贡献是多少呢？答：对ｇdp 的贡献是3美元。
ｇdp 只包括最终物品的价值，因为中间物品的价值已经包括在最终物品的价格中了.４ .许多年以前,peggy 为了收集唱片而花了500 美元。
今天她在旧货销售中把她收集的物品卖了１０0 美元.这种销售如何影响现期gｄp? 答：现期gdｐ只包括现期生产的物品与劳务，不包括涉及过去生产的东西的交易。
因而这种销售不影响现期gdp.5 .列出gdp的四个组成部分。
各举一个例子.答：gdp等于消费(c)+投资(ｉ）+政府购买(g)＋净出口(nｘ) 消费是家庭用于物品与劳务的支出,如汤姆一家人在麦当劳吃午餐.投资是资本设备、存货、新住房和建筑物的购买,如通用汽车公司建立一个汽车厂.政府购买包括地方政府、州政府和联邦政府用于物品与劳务的支出，如海军购买了一艘潜艇．净出口等于外国人购买国内生产的物品(出口)减国内购买的外国物品(进口)。
宏观经济学第五版课后习题答案
第十二章国民收入核算1.宏观经济学和微观经济学有什么联系和区别？为什么有些经济活动从微观看是合理的，有效的，而从宏观看却是不合理的，无效的？解答：两者之间的区别在于：(1)研究的对象不同。
微观经济学研究组成整体经济的单个经济主体的最优化行为，而宏观经济学研究一国整体经济的运行规律和宏观经济政策。
(2)解决的问题不同。
微观经济学要解决资源配置问题，而宏观经济学要解决资源利用问题。
(3)中心理论不同。
微观经济学的中心理论是价格理论，所有的分析都是围绕价格机制的运行展开的，而宏观经济学的中心理论是国民收入(产出)理论，所有的分析都是围绕国民收入(产出)的决定展开的。
(4)研究方法不同。
微观经济学采用的是个量分析方法，而宏观经济学采用的是总量分析方法。
两者之间的联系主要表现在：(1)相互补充。
经济学研究的目的是实现社会经济福利的最大化。
为此，既要实现资源的最优配置，又要实现资源的充分利用。
微观经济学是在假设资源得到充分利用的前提下研究资源如何实现最优配置的问题，而宏观经济学是在假设资源已经实现最优配置的前提下研究如何充分利用这些资源。
它们共同构成经济学的基本框架。
(2)微观经济学和宏观经济学都以实证分析作为主要的分析和研究方法。
(3)微观经济学是宏观经济学的基础。
当代宏观经济学越来越重视微观基础的研究，即将宏观经济分析建立在微观经济主体行为分析的基础上。
由于微观经济学和宏观经济学分析问题的角度不同，分析方法也不同，因此有些经济活动从微观看是合理的、有效的，而从宏观看是不合理的、无效的。
例如，在经济生活中，某个厂商降低工资，从该企业的角度看，成本低了，市场竞争力强了，但是如果所有厂商都降低工资，则上面降低工资的那个厂商的竞争力就不会增强，而且职工整体工资收入降低以后，整个社会的消费以及有效需求也会降低。
同样，一个人或者一个家庭实行节约，可以增加家庭财富，但是如果大家都节约，社会需求就会降低，生产和就业就会受到影响。
曼昆宏观经济学原理第五版chap33to35课后习题答案(中文)
答：这种“为了安全的资本外逃”对美国经济是件好事。
当外国人增加了对美国政府债券的需求时，这种行动减少了美国的资本净流出。
国外净投资减少时，美国可贷资金市场上的可贷资金需求减少，可贷资金的需求减少使利率下降，利率下降增加了国内投资，减少了国民储蓄。
资本净流出减少使得美国外汇市场上的美元供给减少，外汇市场上美元供给的减少引起实际汇率上升，实际汇率上升使贸易余额倾向于赤字。
13．假设美国共同基金突然决定更多地在加拿大投资。
A．加拿大的资本净流出、储蓄和国内投资会发生什么变动?答：加拿大的资本净流出会下降，加拿大的国内投资会增加，储蓄会下降。
B．这对加拿大资本存量的长期影响是什么?答：这会增加加拿大的长期资本存量。
C．资本存量的这种变化将如何影响加拿大劳动市场？这种美国在加拿大的投资使加拿大工人状况变好还是变坏?答：资本存量的这种变化会增加加拿大劳动市场的劳动需求。
这种美国在加拿大的投资使加拿大工人状况变好。
D．你认为这将使美国工人状况变好还是变坏？你能想到有什么原因一般会使这对美国公民的影响与对美国工人的影响不同?答：这将使美国工人状况变坏。
因为美国共同基金增加在加拿大的投资增加了美国公民的投资利润，但由于国内投资下降，美国工人的情况变坏。
第十二篇短期经济波动第三十三章总需求与总供给复习题1．写出当经济进入衰退时下降的两个宏观经济变量。
写出当经济进入衰退时上升的一个宏观经济变量。
答：当经济进入衰退时，实际GDP和投资支出下降，失业率上升。
2．画出一个有总需求、短期总供给和长期总供给的曲线的图。
仔细并正确地标出坐标轴。
答：图33—1经济的长期均衡3．列出并解释总需求曲线向右下方倾斜的三个原因。
答：为了理解总需求曲线向右下方倾斜的原因，我们必须考察物价水平如何影响消费、投资和净出口的物品与劳务需求量。
(1)庇古的财富效应：物价水平下降使消费者感到更富裕，这又鼓励他们更多地支出，消费支出增加意味着物品与劳务的需求量更大。
宏观经济学习题答案(曼昆第五版)
第八篇宏观经济学的数据第二十三章一国收入的衡量复习题 1 ．解释为什么一个经济的收入必定等于其支出? 答：对一个整体经济而言，收入必定等于支出。
因为每一次交易都有两方：买者和卖者。
一个买者的1 美元支出是另一个卖者的1 美元收入。
因此，交易对经济的收入和支出作出了相同的贡献。
由于GDP 既衡量总收入 135 又衡量总支出，因而无论作为总收入来衡量还是作为总支出来衡量，GDP 都相等。
2 ．生产一辆经济型轿车或生产一辆豪华型轿车，哪一个对GDP 的贡献更大？为什么？答:生产一辆豪华型轿车对GDP 的贡献大。
因为GDP 是在某一既定时期一个国家内生产的所有最终物品与劳务的市场价值.由于市场价格衡量人们愿意为各种不同物品支付的量，所以市场价格反映了这些物品的市场价值。
由于一辆豪华型轿车的市场价格高于一辆经济型轿车的市场价格，所以一辆豪华型轿车的市场价值高于一辆经济型轿车的市场价值，因而生产一辆豪华型轿车对GDP 的贡献更大。
3 ．农民以2 美元的价格把小麦卖给面包师。
面包师用小麦制成面包,以3 美元的价格出售。
这些交易对 GDP 的贡献是多少呢？答：对GDP 的贡献是3 美元。
GDP 只包括最终物品的价值，因为中间物品的价值已经包括在最终物品的价格中了.4 ．许多年以前，Peggy 为了收集唱片而花了500 美元。
今天她在旧货销售中把她收集的物品卖了100 美元.这种销售如何影响现期GDP？答：现期GDP 只包括现期生产的物品与劳务，不包括涉及过去生产的东西的交易。
因而这种销售不影响现期GDP.5 ．列出GDP 的四个组成部分。
各举一个例子。
答：GDP 等于消费（C)+投资(I)+政府购买(G）+净出口（NX) 消费是家庭用于物品与劳务的支出，如汤姆一家人在麦当劳吃午餐.投资是资本设备、存货、新住房和建筑物的购买，如通用汽车公司建立一个汽车厂.政府购买包括地方政府、州政府和联邦政府用于物品与劳务的支出，如海军购买了一艘潜艇。
(完整版)曼昆宏观经济学原理答案
第一篇导言复习题第一章宏观经济学的科学1、解释宏观经济学和微观经济学之间的差距，这两个领域如何相互关联？【答案】微观经济学研究家庭和企业如何作出决策以及这些决策在市场上的相互作用。
微观经济学的中心原理是家庭和企业的最优化——他们在目的和所面临的约束条件下可以让自己的境况更好。
而相对的，宏观经济学研究经济的整体情况，它主要关心总产出、总就业、一般物价水平和国际贸易等问题，以及这些宏观指标的波动趋势与规律。
应该看到，宏观经济学研究的这些宏观经济变量是以经济体系中千千万万个体家庭和企业之间的相互作用所构成的。
因此，微观经济决策总是构成宏观经济模型的基础，宏观经济学必然依靠微观经济基础。
2、为什么经济学家建立模型？【答案】一般来说，模型是对某些具体事物的抽象，经济模型也是如此。
经济模型可以简洁、直接地描述所要研究的经济对象的各种关系。
这样，经济学家可以依赖模型对特定的经济问题进行研究；并且，由于经济实际不可控，而模型是可控的，经济学家可以根据研究需要，合理、科学的调整模型来研究各种经济情况。
另外，经济模型一般是数学模型，而数学是全世界通用的科学语言，使用规范、标准的经济模型也有利于经济学家正确表达自己的研究意图，便于学术交流。
3、什么是市场出清模型？什么时候市场出清的假设是适用的？【答案】市场出清模型就是供给与需求可以在价格机制调整下很快达到均衡的模型。
市场出清模型的前提条件是价格是具有伸缩性的（或弹性）。
但是，我们知道价格具有伸缩性是一个很强的假设，在很多实际情况下，这个假设都是不现实的。
比如：劳动合同会使劳动力价格在一段时期内具有刚性。
因此，我们必须考虑什么情况下价格具有伸缩性是合适的。
现在一般认为，在研究长期问题时，假设价格具有伸缩性是合理的；而在研究短期问题时，最好假设价格具有刚性。
因为，从长期看，价格机制终将发挥作用，使市场供需平衡，即市场出清，而在短期，价格机制因其他因素制约，难以很快使市场出清。
曼昆经济学原理(第五版)课后答案
第十二章税制的设计复习题1．在过去的几十年来，政府的增长比经济中的其他部分快还是慢?答：在过去几十年间，政府的增长比经济中其他部分快。
数据表明，美国经济中包括联邦、州和地方政府在内的政府收入在总收人中所占百分比的增长速度快于经济中其他部分。
2．美国联邦政府收入最重要的两个来源是什么?答：美国联邦政府收入最重要的两个来源是个人收入所得税和用于社会保障的工薪税。
3．解释公司利润如何双重纳税。
答：当企业赚到利润时，它要按公司所得税交税；当企业用其利润向公司股东支付股息时，按个人所得税第二次交税。
4．为什么纳税人的税收负担大于政府得到的收入?答：因为纳税人的税收负担除了向政府交纳的税收之外，还包括两种成本：一是税收改变了激励所引起的资源配置扭曲；二是遵守税法的管理负担。
这两种成本没有政府的收入作为补偿。
因此，纳税人的税收负担大于政府得到的收入。
5．为什么一些经济学家支持对消费征税，而不是对收入征税?答：因为对收入征税扭曲了对人们储蓄的激励，鼓励人们少储蓄。
如果政府采取消费税，储蓄起来的全部收入在最后支出前都不征税，就不会扭曲人们的储蓄决策。
6．举出富有的纳税人应该比贫穷纳税人多纳税的两种观点。
答：这方面的观点有受益原则和能力纳税原则。
受益原则认为：人们应该根据他们从政府服务中得到的利益来纳税。
通常富人从公共服务中受益多，他们应该多纳税。
能力纳税原则认为：应该根据一个人所能承受的负担来对这个人征税。
显然，富人的财务承受能力强于穷人，富人应该多纳税。
7．什么是横向平等概念。
为什么运用这个概念是困难的?答：横向平等是指主张有相似支付能力的纳税人应该缴纳等量税收的思想。
这一原则面临的问题是什么决定两个纳税人是相似的。
每个纳税人在许多方面不同，为了评价税收是不是横向平等，必须决定哪些差别对纳税人的支付能力是相关的，哪些是不相关的。
这些相关关系的确定是复杂而困难的。
它不仅涉及经济学问题，还涉及价值观问题，很难说确定的结果是否公平。
曼昆(经济学原理)第五版宏观经济学27
基本金融工具
7
主动学习 1
现值
你正在考虑以7万美元买一块6亩的土地，这块地在 5年后会值10万美元
A. 如果 r = 0.05，你是否应该买？ B. 如果 r = 0.10，你是否应该买？
8
主动学习 1
参考答案
你正在考虑以7万美元买一块6亩的土地，这块地在 5年后会值10万美元 A. 如果 r = 0.05，你是否应该买？
保险允许风险分摊，能使风险厌恶的人更好： 比如，对于房子着火的风险，一万个人承担万分 之一的风险比你自己一个人独自承担全部风险容 易得多
基本金融工具
15
保险市场的两个问题
1. 逆向选择： 高风险的人从保险的保护中获益更大，所以高风 险的人比低风险的人更可能申请保险
2. 道德风险： 人们在购买保险之后，对他们谨慎从事以避免风 险的激励小了
未来货币量的现值：用现行利率产生一定量未来货 币所需要的现在货币量
相关概念: 货币量的未来值：在现行利率既定时，现在货币 量将带来的未来货币量
基本金融工具
3
例 1: 一个简单的存款
以5%的利率在银行存款$100，这笔钱的未来值是多 少？
N 年以后， FV = $100(1 + 0.05)N
3年以后， FV = $100(1 + 0.05)3 = $115.76
由于复利，利率的微小差别在长期会产生巨大的差 别
例如：买$1000微软的股票，并持有30年 如果回报率 = 0.08, FV = $10,063 如果回报率 = 0.10, FV = $17,450
基本金融工具
10
70规则
70规则： 如果一个变量每年按x%增长，那么大约在70/x年 以后，该变量翻一番
曼昆_宏观经济学_第五版答案（可直接复制）
曼昆_宏观经济学_第五版答案（可直接复制）第一篇导言复习题第一章宏观经济学的科学1、解释宏观经济学和微观经济学之间的差距，这两个领域如何相互关联？【答案】微观经济学研究家庭和企业如何作出决策以及这些决策在市场上的相互作用。
微观经济学的中心原理是家庭和企业的最优化——他们在目的和所面临的约束条件下可以让自己的境况更好。
而相对的，宏观经济学研究经济的整体情况，它主要关心总产出、总就业、一般物价水平和国际贸易等问题，以及这些宏观指标的波动趋势与规律。
应该看到，宏观经济学研究的这些宏观经济变量是以经济体系中千千万万个体家庭和企业之间的相互作用所构成的。
因此，微观经济决策总是构成宏观经济模型的基础，宏观经济学必然依靠微观经济基础。
2、为什么经济学家建立模型？【答案】一般来说，模型是对某些具体事物的抽象，经济模型也是如此。
经济模型可以简洁、直接地描述所要研究的经济对象的各种关系。
这样，经济学家可以依赖模型对特定的经济问题进行研究；并且，由于经济实际不可控，而模型是可控的，经济学家可以根据研究需要，合理、科学的调整模型来研究各种经济情况。
另外，经济模型一般是数学模型，而数学是全世界通用的科学语言，使用规范、标准的经济模型也有利于经济学家正确表达自己的研究意图，便于学术交流。
3、什么是市场出清模型？什么时候市场出清的假设是适用的？【答案】市场出清模型就是供给与需求可以在价格机制调整下很快达到均衡的模型。
市场出清模型的前提条件是价格是具有伸缩性的（或弹性）。
但是，我们知道价格具有伸缩性是一个很强的假设，在很多实际情况下，这个假设都是不现实的。
比如：劳动合同会使劳动力价格在一段时期内具有刚性。
因此，我们必须考虑什么情况下价格具有伸缩性是合适的。
现在一般认为，在研究长期问题时，假设价格具有伸缩性是合理的；而在研究短期问题时，最好假设价格具有刚性。
因为，从长期看，价格机制终将发挥作用，使市场供需平衡，即市场出清，而在短期，价格机制因其他因素制约，难以很快使市场出清。
曼昆宏观经济学原理答案
第一篇导言复习题第一章宏观经济学的科学1、解释宏观经济学与微观经济学之间的差距,这两个领域如何相互关联？【答案】微观经济学研究家庭与企业如何作出决策以及这些决策在市场上的相互作用。
微观经济学的中心原理就是家庭与企业的最优化——她们在目的与所面临的约束条件下可以让自己的境况更好。
而相对的,宏观经济学研究经济的整体情况,它主要关心总产出、总就业、一般物价水平与国际贸易等问题,以及这些宏观指标的波动趋势与规律。
应该瞧到,宏观经济学研究的这些宏观经济变量就是以经济体系中千千万万个体家庭与企业之间的相互作用所构成的。
因此,微观经济决策总就是构成宏观经济模型的基础,宏观经济学必然依靠微观经济基础。
2、为什么经济学家建立模型？【答案】一般来说,模型就是对某些具体事物的抽象,经济模型也就是如此。
经济模型可以简洁、直接地描述所要研究的经济对象的各种关系。
这样,经济学家可以依赖模型对特定的经济问题进行研究;并且,由于经济实际不可控,而模型就是可控的,经济学家可以根据研究需要,合理、科学的调整模型来研究各种经济情况。
另外,经济模型一般就是数学模型,而数学就是全世界通用的科学语言,使用规范、标准的经济模型也有利于经济学家正确表达自己的研究意图,便于学术交流。
3、什么就是市场出清模型？什么时候市场出清的假设就是适用的？【答案】市场出清模型就就是供给与需求可以在价格机制调整下很快达到均衡的模型。
市场出清模型的前提条件就是价格就是具有伸缩性的(或弹性)。
但就是,我们知道价格具有伸缩性就是一个很强的假设,在很多实际情况下,这个假设都就是不现实的。
比如:劳动合同会使劳动力价格在一段时期内具有刚性。
因此,我们必须考虑什么情况下价格具有伸缩性就是合适的。
现在一般认为,在研究长期问题时,假设价格具有伸缩性就是合理的;而在研究短期问题时, 最好假设价格具有刚性。
因为,从长期瞧,价格机制终将发挥作用,使市场供需平衡,即市场出清,而在短期,价格机制因其她因素制约,难以很快使市场出清。
宏观经济学第五版课后答案(共10篇)
宏观经济学第五版课后答案(共10篇)宏观经济学第五版课后答案（一）: 宏观经济学习题3 ，请大家帮忙做做！非常感谢！5、假设在两部门经济中，C=50+0.8Y，I=50。
（C为消费，I为投资）• （1）求均衡的国民收入Y、C、S分别为多少（2）投资乘数是多少• (3)如果投资增加20（即△I=20），国民收入将如何变化若充分就业的YF=800，经济存在紧缩还是膨胀其缺口是多少6、假如某人的边际消费倾向恒等于1/2，他的收支平衡点是8000美元，若他的收入为1万美元，试计算：他的消费和储蓄各为多少？7、假设经济模型为：C=20+0.75(Y-T)；I=380；G=400；T=0.20Y；Y=C+I+G。
• （1）计算边际消费倾向。
（2）计算均衡的收入水平。
• （3）在均衡的收入水平下，政府预算盈余为多少？1 Y=C+I=0.8Y+50+50=0.8Y+100 ,Y=500,I=50,C=450,ki=1/(1-0.8)=5I增加20,Y增加100,紧缩,缺口800-500=3002 边际消费倾向1/2设消费函数c=a+0.5y收支平衡点80008000=a+4000,a=4000c=4000+0.5yy=10000,c=9000,s=10003 dc/dy=0.75*0.8=0.6y=c+i+g=20+0.75(y-0.2y)+380+400=0.6y+800,y=2023预算盈余bs=t-g=400-400=0宏观经济学第五版课后答案（二）: 普通物理学_(第五版) 课后习题答案-1 分析与解 (1) 质点在t 至(t ＋Δt)时间内沿曲线从P 点运动到P′点,各量关系如图所示,其中路程Δs ＝PP′,位移大小｜Δr｜＝PP′,而Δr ＝｜r｜-｜r｜表示质点位矢大小的变化量,三个量的物理含义不同,在曲线运动中大小也不相等(注：在直线运动中有相等的可能)．但当Δt→0 时,点P′无限趋近P点,则有｜dr｜＝ds,但却不等于dr．故选(B)．(2) 由于｜Δr ｜≠Δs,故 ,即｜｜≠ ．但由于｜dr｜＝ds,故 ,即｜｜＝．由此可见,应选(C)．1-2 分析与解表示质点到坐标原点的距离随时间的变化率,在极坐标系中叫径向速率．通常用符号vr表示,这是速度矢量在位矢方向上的一个分量；表示速度矢量；在自然坐标系中速度大小可用公式计算,在直角坐标系中则可由公式求解．故选(D)．1-3 分析与解表示切向加速度at,它表示速度大小随时间的变化率,是加速度矢量沿速度方向的一个分量,起改变速度大小的作用；在极坐标系中表示径向速率vr(如题1 -2 所述)；在自然坐标系中表示质点的速率v；而表示加速度的大小而不是切向加速度at．因此只有(3) 式表达是正确的．故选(D)． 1-4 分析与解加速度的切向分量at起改变速度大小的作用,而法向分量an 起改变速度方向的作用．质点作圆周运动时,由于速度方向不断改变,相应法向加速度的方向也在不断改变,因而法向加速度是一定改变的．至于at是否改变,则要视质点的速率情况而定．质点作匀速率圆周运动时,at恒为零；质点作匀变速率圆周运动时,at为一不为零的恒量,当at改变时,质点则作一般的变速率圆周运动．由此可见,应选(B)．1-5 分析与解本题关键是先求得小船速度表达式,进而判断运动性质．为此建立如图所示坐标系,设定滑轮距水面高度为h,t 时刻定滑轮距小船的绳长为l,则小船的运动方程为 ,其中绳长l 随时间t 而变化．小船速度 ,式中表示绳长l 随时间的变化率,其大小即为v0,代入整理后为 ,方向沿x 轴负向．由速度表达式,可判断小船作变加速运动．故选(C)．1-6 分析位移和路程是两个完全不同的概念．只有当质点作直线运动且运动方向不改变时,位移的大小才会与路程相等．质点在t 时间内的位移Δx 的大小可直接由运动方程得到：,而在求路程时,就必须注意到质点在运动过程中可能改变运动方向,此时,位移的大小和路程就不同了．为此,需根据来确定其运动方向改变的时刻tp ,求出0～tp 和tp～t 内的位移大小Δx1 、Δx2 ,则t 时间内的路程 ,如图所示,至于t ＝4.0 s 时质点速度和加速度可用和两式计算．解 (1) 质点在4.0 s内位移的大小宏观经济学第五版课后答案（三）: 曼昆的宏观经济学第五版中第26章习题的问题第九题最后一个问，假设家庭相信，政府现在借款越多意味着未来为了偿还政府债务而必须征收的税率越高，为什么这种信念还会让家庭认为“减税并没有减少家庭整体税单，它仅仅是延期而已。