1、 Demand and SupplyChapter 2A Story：豆你玩 In 2010,an opinion was hyped-up that every disease can be healed by eating mung bean.The humble mung bean was fast becoming a precious commodity and caused mung bean price boom.The netizens called this issue as“豆你玩”.In fact,this case contains a profound economi
2、c principle,that is the market rule.1 1Contents2.1 Theory of Demand2 23 32.2 Theory of Supply2.3 Market Equilibrium2.1.1 Definition of MarketMarket:The places where goods are tradedGoodsBuyer SellerExchange2.1.2 Definition of Demand 需求 Quantity DemandedQuantity Demanded（需求量）:The amount of any good,s
3、ervice,or resource that people are willing and able to buy during a specified period at a specified price-2 bottles a day-14 bottles a week$1$5 3 bottles2.1.2 Definition of Demand 需求 Quantity DemandedQuantity Demanded（需求量）-Refers to only one price DemandDemand（需求）:The range of quantities of any good
4、,service,or resource that people are willing and able to buy during a specified period at each possible price-Tells the quantity demanded at all prices-2 bottles/day$1-1 bottle/day$2 Demand=1,2,5,8,23.6,45.75,2.1.3 Demand Function 需求函数 The relationship between the quantity demanded and all the influ
5、ences on buying plansQd=f(P,I,Pe,T,Px)Main IMain InfluencesnfluencesQd=f(P)PricePriceIncomeExpectationPreferencePrice of Related Goods2.1.4 Demand Curve 需求曲线 A graph of the relationship between the quantity demanded of a good and its price when all other influences on buying plans remain the samePQT
6、he demand curve illustrates the law of demand2.1.5 The Law of Demand 需求规律The law of demand states:The law of demand states:Other things remaining the same,if the price of a good rises,the quantity demanded of that good decreases;and if the price of a good falls,the quantity demanded of that good inc
7、reases2.1.5 The Law of Demand 需求规律Thinking that:Is there any exception?$1$1$0.5 2.1.6 Changes in DemandChange in the Change in the Quantity Demanded Quantity Demanded 需求量变动A change in the quantity of a good people plan to buy that results from a change in the price of the good(when other influences
8、remain the same)Change in Change in Demand Demand 需求变动A change in the quantity of a good people plan to buy when any influence other than the price of the good changesPQ0P0Q0P1Q1DQ0*Q1*Thinking:What are the differences?Change in the Quantity DemandedPriceOthersResultChangedUnchangedUnchangedChangedA
9、 movement along the demand curveThe demand curve shiftsChange in DemandMain InfluencesMain InfluencesPrice:Change of quantity demandedOthers:Change of demandPIPeTPxSubstituteComplement Qd D Curve Exercise&Homework1、保持其他因素不变，某种商品价格下降则（）A、需求增加 B、需求减少C、需求量增加 D、需求量减少2、消费者预期某商品未来价格要上升，则对该商品当前的需求会（）A、减少 B
10、、增加 C、不变 D、以上三种均有可能3、所有下列因素除哪一种以外都会使需求曲线移动（）A、消费者收入变化 B、商品价格下降C、相关产品价格下降 D、消费者偏好变化4、A和B是替代品，则A的价格下降会造成（）A、A的需求曲线右移 B、A的需求曲线左移C、B的需求曲线右移 D、B的需求曲线左移5、某月内，X产品的替代品的价格上升和互补品的价格上升分别引起X产品的需求量变动50单位和80单位，则在它们的共同作用下，该月X产品的需求量（）A、增加30单位 B、减少30单位C、增加130单位 D、减少130单位6、指出下列几种情况下，移动电话的需求曲线是向左移动、向右移动，还是不移动？（1）卫生部门发
11、表报告，移动电话的辐射线会造成记忆力减退，引发老年痴呆（2）移动电话价格下降（3）消费者收入增加（4）电信局的移动电话通话费降低（5）生产移动电话的工人工资增加了1 1Contents2.1 Theory of Demand2 23 32.2 Theory of Supply2.3 Market Equilibrium2.2.1 Definition of Supply Quantity suppliedQuantity supplied:The amount of any good,service,or resource that people are willing and able to
12、 sell during a specified period at a specified price-Refers to only one price SupplySupply:The range of quantities of any good,service,or resource that people are willing and able to sell during a specified period at each possible price-Tells the quantity supplied at all prices2.2.2 Supply Function
13、The relationship between the quantity supplied and all the influences on selling plansQs=f(P,C,Pe,Px T,)Main IMain InfluencesnfluencesQS=f(P)PricePriceCostExpectationPrice of Related GoodsProductivity2.2.3 Supply Curve A graph of the relationship between the quantity supplied of a good and its price
14、 when all other influences on selling plans remain the sameThe supply curve illustrates the law of supplyPQ2.2.4 The Law of SupplyThe law of supply states:The law of supply states:Other things remaining the same,if the price of a good rises,the quantity supplied of that good increases;and if the pri
15、ce of a good falls,the quantity supplied of that good decreases2.2.5 Changes in SupplyChange in the Change in the Quantity SuppliedQuantity SuppliedA change in the quantity of a good people plan to sell that results from a change in the price of the good(when other influences remain the same)Change
16、in Change in SupplySupplyA change in the quantity of a good people plan to sell when any influence other than the price of the good changesMain InfluencesMain InfluencesPrice:Change of quantity suppliedOthers:Change of supplyPCPePxTSubstituteComplement Qs S Curve Exercise&Homework1、在得出某商品的供给曲线时，下列因素
17、除哪一种外均保持常量（）A、技术水平 B、劳动力价格C、该商品价格 D、生产者对价格的期望2、生产者预期某商品未来价格要下降，则对该商品当前的供给会（）A、增加 B、减少C、不变 D、以上三种均有可能3、建筑工人工资提高将使（）A、新房子供给曲线左移 B、新房子供给曲线右移C、新房子需求曲线左移 D、新房子需求曲线右移4、假如生产某种产品所需原料价格降低了，则这种商品的（）A、需求曲线左移 B、供给曲线左移C、需求曲线右移 D、供给曲线右移5、下列事件对产品X的供给有何影响？（1）生产X的技术有重大革新（2）生产X企业数目减少了（3）生产X的人工和原材料价格上涨了（4）预计X的价格会下降1 1
18、Contents2.1 Theory of Demand2 23 32.2 Theory of Supply2.3 Market EquilibriumDemand+Supply=Equilibrium In everyday language,“equilibrium”means“opposing forces are in balance.”In a market,the opposing forces are those of demand and supply Buyers want the lowest possible price,and the lower the price,t
19、he greater is the quantity that they plan to buy Sellers want the highest possible price,and the higher the price,the greater is the quantity that they plan to sell2.3.1 Definition of Market EquilibriumPQ0P2Qd2P0Q0SDQs2Qs1Qd1P1Market EquilibriumMarket EquilibriumWhen the quantity demanded equals the
20、 quantity supplied(and the demand price equals the supply price)Occurs at the intersection of the demand curve and the supply curveEquilibrium Price:Equilibrium Price:The price at which the quantity demanded equals the quantity suppliedEquilibrium Quantity:Equilibrium Quantity:The quantity bought an
21、d sold at the equilibrium price2.3.2 Change of Market EquilibriumPQ0SDP0Q0Q1P1P2Q2The equilibrium price and the Demand change in the same direction，so as the equilibrium quantityThe equilibrium price and the Supply change in opposite directions，while the equilibrium quantity and the Supply change in
22、 the same directionPQ0SDP0Q0Q1P1P2Q2The result is decided by the one that changes greaterWhen demand and supply change together-Analysis of the story：豆你玩BuyerSellerTDPeSP0Exercise&Homework 1、已知当某种商品的市场均衡价格为10元的时候，商品的均衡数量是1000件。假定消费者收入增加使这种商品的需求增加了400件，那么在新的均衡价格水平上，商品的均衡数量是（）A、1000件B、大于1000件但小于1400件C
23、、1400件D、以上都不对 2、小麦歉收导致小麦价格上升，准确的说在这个过程中（）A、小麦供给的减少引起需求量下降B、小麦供给的减少引起需求下降C、小麦供给量的减少引起需求量下降D、小麦供给量的减少引起需求下降 3、如果政府对企业出售的商品每件征收5元的税金，那么这种做法将使这种商品（）A、市场价格上升5元 B、市场价格上升小于5元C、市场价格上升大于5元 D、不能确定 4、已知某商品的市场需求函数为Q=30-P，供给函数为Q=3P-10，如果对该商品实行减税，则减税后的市场均衡价格（）A、等于10 B、小于10C、大于10 D、小于或等于10 5、在需求和供给同时减少的情况下（）A、均衡价格
24、和均衡数量都下降B、均衡价格将下降，均衡数量的变化无法确定C、均衡价格的变化无法确定，均衡数量会减少D、均衡价格将上升，均衡数量将下降 6、均衡价格随着（）A、需求和供给的增加而上升B、需求和供给的减少而上升C、需求的减少和供给的增加而上升D、需求的增加和供给的减少而上升7、假设某商品的需求函数为Q=16-2P，供给函数为Q=-4+2P，则：（1）该商品的均衡价格和均衡数量为多少？（2）假设消费者收入增加，需求曲线向右平移4个单位，求收入变化后的需求函数，计算均衡价格和均衡数量，并绘图。（3）假设生产该商品的技术水平有了提高，供给曲线向右平移4各单位，求技术变化后的供给函数，计算均衡价格和均衡
25、数量，并绘图（4）若政府对出售的每单位商品增收2元的销售税，对均衡价格和均衡数量有何影响？征收的每单位税款中，生产者和消费者各支付了多少？（5）若政府对该商品的生产每单位补贴2元，对均衡价格和均衡数量又有何影响？消费者能从中获益吗？实践小游戏 游戏规则：18位参与者，分为买卖双方，每方各9人。每位同学将获得一张扑克牌，牌面的数字代表卖方能接受的最低价格和买方能接受的最高价格，请注意保密 另选3位同学担任市场工作人员 买卖双方自由交易，各自报价，自由还价，达成交易后双方到工作人员处登记并交还手上的牌。交易过程中除讨价还价，不得与其他人交流其它信息。交易时间每轮5分钟 报价规则：卖方报价不得低于手牌数字，买方报价不得高于手牌数字。随时注意工作人员公布的最新成交价，作为进行交易决策的参考 计算收益：买方收益=手牌数字成交价，卖方收益=成交价手牌数字。没有成交则收益为零。多轮交易结束后，将每轮收益加总将奖励收益最高的同学5分 工作人员做好登记，并及时大声报出最新成交价格并依次写在黑板上，供交易者参考 思考：游戏过程和结果说明了什么？
