经济学原理曼昆讲义PPT学习教案

1、会计学1经济学原理曼昆讲义经济学原理曼昆讲义2第1页/共59页3第2页/共59页4第3页/共59页5第4页/共59页6第5页/共59页7第6页/共59页8第7页/共59页9第8页/共59页10第9页/共59页11第10页/共59页Catherines Demand Schedule and Demand CurveDemand curveThe demand schedule is a table that shows the quantity demanded at each price. The demand curve, which graphs the demand schedule,

2、 illustrates how the quantity demanded of the good changes as its price varies. Because a lower price increases the quantity demanded, the demand curve slopes downward.Price ofIce-CreamConeQuantity ofConesDemanded$0.000.501.001.502.002.503.0012 cones108642001210 1191 2 3 4 5 6 7 8Quantity of Ice-Cre

3、am Cones $3.002.502.001.501.000.50Price of Ice-Cream Cones 1. A decreasein price . . .2. . . . increases quantityof cones demanded.12第11页/共59页13第12页/共59页Market Demand as the Sum of Individual DemandsThe quantity demanded in a market is the sum of the quantities demanded by all the buyers at each pri

4、ce. Thus, the market demand curve is found by adding horizontally the individual demand curves. At a price of $2.00, Catherine demands 4 ice-cream cones, and Nicholas demands 3 ice-cream cones. The quantity demanded in the market at this price is 7 cones.14第13页/共59页Market Demand as the Sum of Indivi

5、dual DemandsDCatherine012101191 2 3 4 5 6 7 8Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price ofIce-CreamConesCatherines demandDNicholas01 2 3 4 5 6 7Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price ofIce-CreamConesNicholass demand+=DMarket0182 4 6 8 10 121416Quantity of Ice-Crea

6、m Cones $3.002.502.001.501.000.50Price ofIce-CreamConesMarket demand15第14页/共59页16第15页/共59页Shifts in the Demand CurvePrice of Ice-Cream Cones Quantity of Ice-Cream Cones 0Demand curve, D1Demand curve, D3Demand curve, D2Increase inDemand Decrease inDemand Any change that raises the quantity that buyer

7、s wish to purchase at any given price shifts the demand curve to the right. Any change that lowers the quantity that buyers wish to purchase at any given price shifts the demand curve to the left.17第16页/共59页18第17页/共59页19第18页/共59页20第19页/共59页21第20页/共59页Variables That Influence BuyersThis table lists t

8、he variables that affect how much consumers choose to buy of any good. Notice the special role that the price of the good plays: A change in the goods price represents a movement along the demand curve, whereas a change in one of the other variables shifts the demand curve.22第21页/共59页23“What is the

9、best way tostop this?”第22页/共59页24第23页/共59页25第24页/共59页Shifts in the Demand Curve versus Movements along the Demand CurvePrice of Cigarettes, per Pack Number of Cigarettes Smoked per Day0D1D2A policy to discourage smoking shifts the demand curve to the left1020$2.00BA(a) A Shift in the Demand CurveIf

10、warnings on cigarette packages convince smokers to smoke less, the demand curve for cigarettes shifts to the left. In panel (a), the demand curve shifts from D1 to D2. At a price of $2.00 per pack, the quantity demanded falls from 20 to 10 cigarettes per day, as reflected by the shift from point A t

11、o point B. By contrast, if a tax raises the price of cigarettes, the demand curve does not shift. Instead, we observe a movement to a different point on the demand curve. In panel (b), when the price rises from $2.00 to $4.00, the quantity demanded falls from 20 to 12 cigarettes per day, as reflecte

12、d by the movement from point A to point C.Price of Cigarettes, per Pack Number of Cigarettes Smoked per Day0D1A tax that raises the price of cigarettes results in a movement along the demand curve12202.00CA(b) A Movement along the Demand Curve$4.0026第25页/共59页27第26页/共59页28第27页/共59页29第28页/共59页Bens Sup

13、ply Schedule and Supply CurvePrice ofIce-creamConeQuantity Of ConesSupplied$0.000.501.001.502.002.503.000 cones012345Supply curveThe supply schedule is a table that shows the quantity supplied at each price. This supply curve, which graphs the supply schedule, illustrates how the quantity supplied o

14、f the good changes as its price varies. Because a higher price increases the quantity supplied, the supply curve slopes upward.01210 1191 2 3 4 5 6 7 8Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price of Ice-Cream Cones 1. An increasein price . . .2. . . . increases quantity of cones suppli

15、ed.30第29页/共59页31第30页/共59页Market Supply as the Sum of Individual SuppliesThe quantity supplied in a market is the sum of the quantities supplied by all the sellers at each price. Thus, the market supply curve is found by adding horizontally the individual supply curves. At a price of $2.00, Ben suppl

16、ies 3 ice-cream cones, and Jerry supplies 4 ice-cream cones. The quantity supplied in the market at this price is 7 cones.32第31页/共59页Market Supply as the Sum of Individual SuppliesSBen01 2 3 4 5 6 7Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price ofIce-CreamConesBens supplySJerry01 2 3 4 5

17、 6 7Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price ofIce-CreamConesJerrys supply+=SMarket0182 4 6 8 10121416Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price ofIce-CreamConesMarket supply33第32页/共59页34第33页/共59页Shifts in the Supply CurvePrice of Ice-Cream Cones Quantity of Ice-Cre

18、am Cones 0Supply curve, S1Supply curve, S3Supply curve, S2Increase inSupply DecreaseIn supplyAny change that raises the quantity that sellers wish to produce at any given price shifts the supply curve to the right. Any change that lowers the quantity that sellers wish to produce at any given price s

19、hifts the supply curve to the left.35第34页/共59页36第35页/共59页37第36页/共59页38第37页/共59页Variables That Influence SellersThis table lists the variables that affect how much producers choose to sell of any good. Notice the special role that the price of the good plays: A change in the goods price represents a

20、movement along the supply curve, whereas a change in one of the other variables shifts the supply curve.39第38页/共59页40第39页/共59页41第40页/共59页42第41页/共59页The Equilibrium of Supply and DemandSupply01210 1191 2 3 4 5 6 7 8Quantity of Ice-Cream Cones $3.002.502.001.501.000.50Price ofIce-CreamCones Equilibriu

21、mDemandEquilibriumpriceEquilibriumquantityThe equilibrium is found where the supply and demand curves intersect. At the equilibrium price, the quantity supplied equals the quantity demanded. Here the equilibrium price is $2.00: At this price, 7 ice-cream cones are supplied, and 7 ice-cream cones are

22、 demanded.43第42页/共59页44第43页/共59页45第44页/共59页Markets Not in EquilibriumPrice ofIce-CreamConesQuantity of Ice-Cream Cones 0Demand7$2.50(a) Excess SupplyIn panel (a), there is a surplus. Because the market price of $2.50 is above the equilibrium price, the quantity supplied (10 cones) exceeds the quanti

23、ty demanded (4 cones). Suppliers try to increase sales by cutting the price of a cone, and this moves the price toward its equilibrium level. In panel (b), there is a shortage. Because the market price of $1.50 is below the equilibrium price, the quantity demanded (10 cones) exceeds the quantity sup

24、plied (4 cones). With too many buyers chasing too few goods, suppliers can take advantage of the shortage by raising the price. Hence, in both cases, the price adjustment moves the market toward the equilibrium of supply and demand(b) Excess demand2.00Supply Surplus 4Quantitydemanded10Quantitysuppli

25、edPrice ofIce-CreamConesQuantity of Ice-Cream Cones 0Demand71.50$2.00Supply Shortage4Quantitysupplied10Quantitydemanded46第45页/共59页47第46页/共59页48第47页/共59页Three Steps for Analyzing Changes in Equilibrium1. Decide whether the event shifts the supply or demand curve (or perhaps both).2. Decide in which d

26、irection the curve shifts.3. Use the supply-and demand diagram to see how the shift changes the equilibrium price and quantity.49第48页/共59页50第49页/共59页How an increase in demand affects the equilibriumSupplyNew equilibriumD2An event that raises quantity demanded at any given price shifts the demand cur

27、ve to the right. The equilibrium price and the equilibrium quantity both rise. Here an abnormally hot summer causes buyers to demand more ice cream. The demand curve shifts from D1 to D2, which causes the equilibrium price to rise from $2.00 to $2.50 and the equilibrium quantity to rise from 7 to 10

28、 cones.Price ofIce-CreamConesQuantity of Ice-Cream Cones 07$2.502.0010D1Initial equilibrium1. Hot weather increases the demand for ice cream . . .2. resulting in a higher price . . .3. and a higherquantity sold.51第50页/共59页52第51页/共59页53第52页/共59页How a Decrease in Supply Affects the EquilibriumS1New eq

29、uilibriumS2An event that reduces quantity supplied at any given price shifts the supply curve to the left. The equilibrium price rises, and the equilibrium quantity falls. Here an increase in the price of sugar (an input) causes sellers to supply less ice cream. The supply curve shifts from S1 to S2

30、, which causes the equilibrium price of ice cream to rise from $2.00 to $2.50 and the equilibrium quantity to fall from 7 to 4 cones.Price ofIce-CreamConesQuantity of Ice-Cream Cones 07$2.502.004DemandInitial equilibrium1. An increase in the price of sugar reducesthe supply of ice cream . . .2. resulting in a higher price . . .3. and a lowerquanti