【導(dǎo)讀】microeconomics?Whatisamarket?nominalprices?Limitedbudgets. Limitedtime. machinery?Howarethesetrade-offsbestmade?Consumers. Limitedines. Consumertheory–describeshow. Workers. jobsorworkplaces?work?Firms. TheoryoftheFirm–describeshowthese. Prices. Prices. Marketeconomies–pricesdeterminedby. TheTheoryoftheFirm. ValidatingaTheory. PositiveAnalysis–statementsthat

　　

【正文】 035.)(630,2ΔΔ ?????PPE DDP032.)(630,2ΔΔ ???PPE SSP169。2020 Pearson Education, Inc. Chapter 1 86 Elasticity: An Application ?Assume the price of wheat is $486,2))(266(550,3 ???DQ)266(486,2 ????DPQ169。2020 Pearson Education, Inc. Chapter 1 87 Elasticity: An Application ?In 2020, the supply and demand for wheat were: ?Supply: QS = 1439 + 267P ?Demand: QD = 2809 – 226P 169。2020 Pearson Education, Inc. Chapter 1 88 Elasticity: An Application QD = QS 2809 226P = 1439 + 267P P = $ per bushel Q = 2809 (226)() = 2181 million bushels Price of wheat fell in nominal terms. 169。2020 Pearson Education, Inc. Chapter 1 89 ShortRun Versus LongRun Elasticity ?Price elasticity varies with the amount of time consumers have to respond to a price ?Shortrun demand and supply curves often look very different from their longrun counterparts 169。2020 Pearson Education, Inc. Chapter 1 90 ShortRun Versus LongRun Elasticity ?Demand ?In general, demand is much more price elastic in the long run ? Consumers take time to adjust consumption habits ? Demand might be linked to another good that changes slowly ? More substitutes are usually available in the long run 169。2020 Pearson Education, Inc. Chapter 1 91 Gasoline: ShortRun and LongRun Demand Curves DSR DLR ? People cannot easily adjust consumption in the short run. ? In the long run, people tend to drive smaller and more fuel efficient cars. Quantity of Gas Price 169。2020 Pearson Education, Inc. Chapter 1 92 ShortRun Versus LongRun Elasticity ?Demand and Durability ?For some durable goods, demand is more elastic in the short run ?If goods are durable, then when price increases, consumers choose to hold on to the good instead of replacing it ?But in long run, older durable goods will have to be replaced 169。2020 Pearson Education, Inc. Chapter 1 93 DSR DLR ? Initially, people may put off immediate car purchase ? In long run, older cars must be replaced Cars: ShortRun and LongRun Demand Curves Quantity of Cars Price 169。2020 Pearson Education, Inc. Chapter 1 94 ShortRun Versus LongRun Elasticity ?Ine elasticity also varies with the amount of time consumers have to respond to an ine change ?For most goods and services, ine elasticity is larger in the long run ?When ine changes, it takes time to adjust spending 169。2020 Pearson Education, Inc. Chapter 1 95 ShortRun Versus LongRun Elasticity ?Ine elasticity of durable goods ?Ine elasticity is less in the long run than in the short run ? Increases in ine mean consumers will want to hold more cars ? Once older cars are replaced, purchases will only be to replace old cars ? Less purchases from ine increase in long run than in short run 169。2020 Pearson Education, Inc. Chapter 1 96 Demand for Gasoline 169。2020 Pearson Education, Inc. Chapter 1 97 Demand for Automobiles 169。2020 Pearson Education, Inc. Chapter 1 98 ShortRun Versus LongRun Elasticity ?Most goods and services: ?Longrun price elasticity of supply is greater than shortrun price elasticity of supply ?Other Goods (durables, recyclables): ?Longrun price elasticity of supply is less than shortrun price elasticity of supply 169。2020 Pearson Education, Inc. Chapter 1 99 SSR Quantity Primary Copper Price ShortRun Versus LongRun Elasticity SLR Due to limited capacity, firms are limited by output constraints in the short run. In the long run, they can expand. 169。2020 Pearson Education, Inc. Chapter 1 100 SSR Quantity Secondary Copper Price ShortRun Versus LongRun Elasticity SLR Price increases provide an incentive to convert scrap copper into new supply. In the long run, this stock of scrap copper begins to fall. 169。2020 Pearson Education, Inc. Chapter 1 101 Supply of Copper 169。2020 Pearson Education, Inc. Chapter 1 102 ShortRun vs. LongRun Elasticity – An Application ?Why are coffee prices very volatile? ?Most of the world’s coffee is produced in Brazil ?Many changing weather conditions affect the crop of coffee, thereby affecting price ?Price following bad weather conditions is usually shortlived ?In long run, prices e back to original levels, all else equal 169。2020 Pearson Education, Inc. Chapter 1 103 Price of Brazilian Coffee 169。2020 Pearson Education, Inc. Chapter 1 104 ShortRun vs. LongRun Elasticity – An Application ?Demand and supply are more elastic in the long run ?In the short run, supply is pletely inelastic ?Weather may destroy part of the fixed supply, decreasing supply ?Demand is relatively inelastic as well ?Price increases significantly 169。2020 Pearson Education, Inc. Chapter 1 105 D P0 S Q0 Quantity Price A freeze or drought decreases the supply of coffee S’ Q1 An Application Coffee Price increases significantly due to inelastic supply and demand P1 169。2020 Pearson Education, Inc. Chapter 1 106 S’ D S P0 Q0 P2 Q2 IntermediateRun 1) Supply and demand are more elastic 2) Price falls back to P2. An Application Coffee Quantity Price 169。2020 Pearson Education, Inc. Chapter 1 107 S P0 Q0 LongRun 1) Supply is extremely elastic 2) Price falls back to P0. 3) Quantity back to Q0. An Application Coffee Quantity Price D 169。2020 Pearson Education, Inc. Chapter 1 108 Predicting the Effects of Changing Market Conditions ?Supply and demand analysis can be used to predict the effects of changing market conditions ?Linear demand and supply must be fit to market data ? Given equilibrium price and quantity along with elasticities of supply and demand, we can calculate the curves that fit the information ? We can then calculate changes in the market 169。2020 Pearson Education, In