中级微观经济学之第四讲：个人与市场需求.ppt

中级微观经济学之第中级微观经济学之第四讲：个人与市场需四讲：个人与市场需求求4.1 Individual DemandnPrice Change As the price of one goods decrease,the quantity of the goods that a consumer purchased will increase,so do the utility that the consumer can attain grow.Two Properties of Individual Demand CurvenThe level of utility that can be attained changes as we move along the curve.nAt every point on the demand curve,the consumer is maximizing utility by satisfying the condition that MRSfc=Pf/Pc.Income ChangesclothingfoodPriceFood3574101641016ABCU1U2U3D1D2D3EGH1Income-Consumption CurveNormal versus Inferior GoodsIncomeFoodIncomeHamburgerEngel CurveInferiorNormalGiffen goodSubstitutes and ComplementsnSubstitute Goods Complement Goods 4.2 Income and Substitution EffectsnTwo effects of prices drop 1.Consumer will tend to buy more of the good that has become cheaper and less of those goods that are now relatively more expensive.2.Because one of the goods is now cheaper,consumers enjoy an increase in real purchasing power.Substitution and Income effectnSubstitution effect:the change in food consumption associated with a change in the price of food,with the level of utility held constant.nIncome effect:the change in food consumption brought about by the increase in purchasing power,with relative prices held constant.clothingfoodABC1C2F1F2DSubstitution effect Income effectTotal effectENormal GoodsRSTU2U1clothingfoodABC1C2F1F2DEInferior GoodRSTU2U1Substitution effect:F1EIncome effect:EF2Total effect:F1F24.3 Market DemandPriceQuantityDADBDCMarket Demand41234.4 Consumer SurplusnIndividual consumer surplus is the difference between the maximum amount that a consumer is willing to pay for a good and the amount that the consumer actually pays.PriceQuantityDP1AOBCConsumer surplus Actual ExpenditureConsumer Surplus and Differential Pricing n景点门票价格该不该不同游客区别对待？峨眉山游玩风景区全价门票为80元人，同时，对学生实行优惠票价：80元人。本地学生凭学生证，可以10元人的价格购得门票。景点门票价格该不该对本地游客、外地游客区别对待？4.5 Network ExternalitiesnPositive network externality:if the quantity of a good demanded by a typical consumer increases in response to the growth in purchases of other consumers.nNegative network externality:if the quantity of a good demanded by a typical consumer decreases in response to the growth in purchases of other consumers.Bandwagon EffectPriceQuantityD20D40D60D80D100Demand30202040 486080100Pure Price Effect Bandwagon EffectSnob EffectD2D4D6D8Demand15,00024681430,000Pure price effectsnob effectnet effectThe Slutsky Equation4.1Total differentiation of Eqs.4.14.2is unknownThe terms on the right must be regarded as constants Cramer RuleThe solution of 4.2 by Cramers Rule4.34.4Dividing both sides of 4.3 by dp1 and assuming that p2 and y do not change4.5All other things being equal(dp1=dp2=0),the rate of change with respect to incomeSubstitution effectIncome effect