经济学原理(英文)4优秀课件

1、1The Market Forces of Supply and demandnA competitive market is a market in which there are many buyers and sellers so that each has a negligible impact on the market price.2What Is Competition?nCompetition: Perfect and Otherwise qPerfect CompetitionnProducts are the samenNumerous buyers and sellers

2、 so that each has no influence over pricenBuyers and Sellers are price takersqMonopolynOne seller, and seller controls price3What Is Competition?nCompetition: Perfect and Otherwise qOligopolynFew sellersnNot always aggressive competitionqMonopolistic CompetitionnMany sellersnSlightly differentiated

3、productsnEach seller may set price for its own product4DEMANDnQuantity demanded is the amount of a good that buyers are willing and able to purchase.nLaw of DemandqThe law of demand states that, other things equal, the quantity demanded of a good falls when the price of the good rises. 5The Demand C

4、urve: The Relationship between Price and Quantity DemandednDemand Schedule qThe demand schedule is a table that shows the relationship between the price of the good and the quantity demanded. 6Catherines Demand Schedule7The Demand Curve: The Relationship between Price and Quantity DemandednDemand Cu

5、rve qThe demand curve is a graph of the relationship between the price of a good and the quantity demanded. 8Figure 1 Catherines Demand Schedule and Demand CurvePrice ofIce-Cream Cone02.502.001.501.000.50123456789 10 11Quantity ofIce-Cream Cones$3.00121. A decrease in price .2. . increases quantity

6、of cones demanded.9Market Demand versus Individual DemandnMarket demand refers to the sum of all individual demands for a particular good or service.nGraphically, individual demand curves are summed horizontally to obtain the market demand curve.10The Market Demand CurvePrice of Ice-Cream ConePrice

7、of Ice-Cream ConePrice of Ice-Cream Cone2.002.002.004371.001.001.008513Quantity of Ice-Cream ConesQuantity of Ice-Cream ConesQuantity of Ice-Cream ConesCatherines DemandNicholass DemandMarket Demand+=The market demand curve is the horizontal sum of the individual demand curves!110DPrice of Ice-Cream

8、 ConesQuantity of Ice-Cream ConesAB81.00$2.004Changes in Quantity Demanded12Shifts in the Demand CurveqConsumer incomeqPrices of related goodsqTastesqExpectationsqNumber of buyers13Figure 3 Shifts in the Demand CurvePrice ofIce-CreamConeQuantity ofIce-Cream ConesIncreasein demandDecreasein demandDem

9、and curve, D3Demandcurve, D1Demandcurve, D2014Shifts in the Demand CurvenConsumer IncomeqAs income increases the demand for a normal good will increase.qAs income increases the demand for an inferior good will decrease.15$3.002.502.001.501.000.502134 56789 101211Price of Ice-Cream ConeQuantity of Ic

10、e-Cream Cones0Increasein demandAn increase in income.D1D2Consumer Income Normal Good16$3.002.502.001.501.000.502134 56789 101211Price of Ice-Cream ConeQuantity of Ice-Cream Cones0Decreasein demandAn increase in income.D1D2Consumer Income Inferior Good17Shifts in the Demand CurvenPrices of Related Go

11、odsqWhen a fall in the price of one good reduces the demand for another good, the two goods are called substitutes.qWhen a fall in the price of one good increases the demand for another good, the two goods are called complements.18SUPPLYnQuantity supplied is the amount of a good that sellers are wil

12、ling and able to sell. nLaw of SupplyqThe law of supply states that, other things equal, the quantity supplied of a good rises when the price of the good rises.19The Supply Curve: The Relationship between Price and Quantity SuppliednSupply ScheduleqThe supply schedule is a table that shows the relat

13、ionship between the price of the good and the quantity supplied. 20Bens Supply Schedule21The Supply Curve: The Relationship between Price and Quantity Supplied nSupply CurveqThe supply curve is the graph of the relationship between the price of a good and the quantity supplied. 22Figure 5 Bens Suppl

14、y Schedule and Supply CurvePrice ofIce-CreamCone02.502.001.501.0012345678910 11Quantity ofIce-Cream Cones$3.00120.501. Anincrease in price .2. . increases quantity of cones supplied.23Market Supply versus Individual SupplynMarket supply refers to the sum of all individual supplies for all sellers of

15、 a particular good or service.nGraphically, individual supply curves are summed horizontally to obtain the market supply curve.24Shifts in the Supply CurvenInput pricesnTechnologynExpectations nNumber of sellers251 5Price of Ice-Cream ConeQuantity of Ice-Cream Cones0S 1.00AC$3.00A rise in the price

16、of ice cream cones results in a movement along the supply curve.Change in Quantity Supplied26Figure 7 Shifts in the Supply CurvePrice ofIce-CreamConeQuantity ofIce-Cream Cones0Increasein supplyDecreasein supplySupply curve, S3curve, SupplyS1Supplycurve, S227SUPPLY AND DEMAND TOGETHERnEquilibrium ref

17、ers to a situation in which the price has reached the level where quantity supplied equals quantity demanded. 28SUPPLY AND DEMAND TOGETHERnEquilibrium PriceqThe price that balances quantity supplied and quantity demanded. qOn a graph, it is the price at which the supply and demand curves intersect.n

18、Equilibrium QuantityqThe quantity supplied and the quantity demanded at the equilibrium price. qOn a graph it is the quantity at which the supply and demand curves intersect. 29At $2.00, the quantity demanded is equal to the quantity supplied!SUPPLY AND DEMAND TOGETHERDemand ScheduleSupply Schedule3

19、0Figure 8 The Equilibrium of Supply and DemandPrice ofIce-CreamCone0123456789101112Quantity of Ice-Cream Cones13EquilibriumquantityEquilibrium priceEquilibriumSupplyDemand$2.0031EquilibriumnSurplusqWhen price equilibrium price, then quantity supplied quantity demanded. nThere is excess supply or a s

20、urplus. nSuppliers will lower the price to increase sales, thereby moving toward equilibrium.32Figure 9 Markets Not in EquilibriumPrice ofIce-CreamCone0SupplyDemand(a) Excess SupplyQuantitydemandedQuantitysuppliedSurplusQuantity ofIce-CreamCones4$2.50102.00733EquilibriumnShortageqWhen price the quan

21、tity supplied. nThere is excess demand or a shortage. nSuppliers will raise the price due to too many buyers chasing too few goods, thereby moving toward equilibrium.34Figure 9 Markets Not in EquilibriumPrice ofIce-CreamCone0Quantity ofIce-CreamConesSupplyDemand(b) Excess DemandQuantitysuppliedQuant

22、itydemanded1.5010$2.0074Shortage35EquilibriumnLaw of supply and demandqThe claim that the price of any good adjusts to bring the quantity supplied and the quantity demanded for that good into balance.36Table 3: Three Steps for Analyzing Changes in Equilibrium37Figure 10 How an Increase in Demand Affects the EquilibriumPrice ofIce-CreamCone0Quantity of Ice-Cream ConesSupplyInitialequilibriumDD3. . . . and a higherquantity sold.2. . . . resultingin a higherprice . . .1. Hot weather increasesthe demand for ice cream . . .2.007New equilibrium$2.501038Three Steps to A