需求及供应弹性课件

Demand and Supply:Demand and Supply:ElasticityElasticity需求及供應：彈性需求及供應：彈性Definition(定義定義)Elasticity of Demand需求彈性需求彈性It refers to the measurement of the responsiveness(反應反應)of quantity demanded for a good,to a change in its prices.當貨品的價格變動時,消費者對需求量的變動的幅度(反應)Elasticity of demand 需求彈性需求彈性Elasticity of Demand需求彈性需求彈性percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=Example one 例子例子 一一:As the price of apples rises from$3.8 to$4.2,the quantity demanded falls from 200 to 120.Calculate the elasticity of demand for apple.當蘋果的價格由當蘋果的價格由$3.8增加至增加至$4.2，需求，需求數量由數量由200下降至下降至120。計算蘋果的需求。計算蘋果的需求彈性。彈性。Elasticity of demand 需求彈性需求彈性Qd:200 120 P:$3.8$4.2percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=120-200(200+120)/2Elasticity of demand 需求彈性需求彈性Qd:200 120 P:$3.8$4.2percentage change in price價格的的轉變百分比價格的的轉變百分比=$4.2-$3.8($4.2+$3.8)/2-801600.44=120-200(200+120)/2=Elasticity of demand 需求彈性需求彈性Qd:200 120 P:$3.8$4.2-801600.44=Elasticity of demand 需求彈性需求彈性Qd:200 120 P:$3.8$4.2-801600.44=X=-5Elasticity of demand 需求彈性需求彈性Qd:200 120 P:$3.8$4.2=-801600.44Example 例子例子:As the price of a mini hi-fi system falls from$2500 to$2000,the quantity demanded rises from 350 to 550.Calculate the elasticity of demand for apple.當一套微型音響組合的價格由當一套微型音響組合的價格由$2500下降下降至至$2000，需求數量由，需求數量由350增加至增加至550。計算微型音響組合的需求彈性。計算微型音響組合的需求彈性。Elasticity of demand 需求彈性需求彈性Qd:350 550 P:$2500$2000percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=$2000-$2500($2500+$2000)/2200450-5002250=550-350(550+350)/2=Elasticity of demand 需求彈性需求彈性Qd:350 550 P:$2500$2000200450-5002250=X=-2Elasticity of demand 需求彈性需求彈性Qd:350 550 P:$2500$2000200450-5002250=Types of Elasticity of Demand 需求彈性的種類需求彈性的種類Unitary Elastic 單一彈性單一彈性Relatively Elastic 相對具相對具彈性彈性Relatively Inelastic 相對欠相對欠彈性彈性Perfectly Elastic 絕對具絕對具彈性彈性Perfectly Inelastic 絕對絕對欠彈性欠彈性Unitary Elastic 單一彈性單一彈性Elasticity of demand 需求彈性需求彈性=1percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=1percentage change in quantity demanded需求數量的轉變百分比需求數量的轉變百分比 Unitary Elastic 單一彈性單一彈性Elasticity of demand 需求彈性需求彈性=1percentage change in price 價格的價格的轉變百分比轉變百分比=PQ0DUnitary Elastic 單一彈性單一彈性Elasticity of demand 需求彈性需求彈性=1Relatively Elastic 相對具相對具彈性彈性Elasticity of demand 需求彈性需求彈性 1percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比1percentage change in quantity demanded需求數量的轉變百分比需求數量的轉變百分比 Relatively Elastic 相對具相對具彈性彈性Elasticity of demand 需求彈性需求彈性 1percentage change in price 價格的價格的轉變百分比轉變百分比PQ0Relatively Elastic 相對具相對具彈性彈性Elasticity of demand 需求彈性需求彈性 1DRelatively Inelastic 相對欠相對欠彈性彈性Elasticity of demand 需求彈性需求彈性 1percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比1percentage change in quantity demanded需求數量的轉變百分比需求數量的轉變百分比 Relatively Inelastic 相對欠相對欠彈性彈性Elasticity of demand 需求彈性需求彈性 1percentage change in price 價格的價格的轉變百分比轉變百分比PQ0Relatively Inelastic 相對欠相對欠彈性彈性Elasticity of demand 需求彈性需求彈性 1DPerfectly Elastic 絕對具絕對具彈性彈性Elasticity of demand 需求彈性需求彈性=percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=Perfectly Elastic 絕對具絕對具彈性彈性Elasticity of demand 需求彈性需求彈性=percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比=PQ0Perfectly Elastic 絕對具絕對具彈性彈性Elasticity of demand 需求彈性需求彈性=DPerfectly Inelastic 絕對欠絕對欠彈性彈性Elasticity of demand 需求彈性需求彈性=0percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=0Perfectly Inelastic 絕對欠絕對欠彈性彈性Elasticity of demand 需求彈性需求彈性=0percentage change in quantity demanded 需求數量的轉變百分比需求數量的轉變百分比=0PQ0Perfectly Inelastic 絕對欠絕對欠彈性彈性Elasticity of demand 需求彈性需求彈性=0D1)Number of Substitutes 代替品的數目代替品的數目2)Degree of Necessity 必需的程度必需的程度3)Proportion of consumers income spent on the good 支出佔消費支出佔消費 者收入的比例者收入的比例4)Time for Adjusting Consumption 調整消費的時間調整消費的時間5)Habit of Consumers 消費者的習慣消費者的習慣Factors Affecting the Elasticity of Demand影響需求彈性的因素影響需求彈性的因素Total revenue means the amount of money obtained by producers.總收益是指生產者獲得的總金額。總收益是指生產者獲得的總金額。Elasticity of Demand and Total Revenue需求彈性和總收益需求彈性和總收益It is the same as the total expenditure paid by consumersorthe total market value of the goods transacted.這相等於消費者支付的這相等於消費者支付的總支出總支出或或產品交易的總市場價值。產品交易的總市場價值。Total Revenue 總收益總收益Price 價格價格Quantity 數量數量x=PQ0DStotal revenue總收益總收益If price and quantity change,total revenue will also change.如果價格和數量轉變，總收益亦會轉變。如果價格和數量轉變，總收益亦會轉變。Price increases,quantity decreases.價格增加，數量減少。價格增加，數量減少。For the case with:original total revenue原本的總收益原本的總收益PQ0Dnew total revenue新的總收益新的總收益PQ0Doriginal total revenue原本的總收益原本的總收益PQ0DPQ0Ddecrease in revenue減少的收益減少的收益increase in revenue新增的收益新增的收益PQ0D22019016013010070456789QPrice($)Suppose the price of the good decreases from$8 to$7.What is the effect on total revenue?10087130DQuantityPrice($)Elastic demandElasticity and change in total revenue 10087130DQuantityPrice($)Elastic demandElasticity and change in total revenue Loss in revenueGain in revenue _ units are sold at$1 less.100 Loss=_$1 100=$100 _ more units are sold at$7.30 Loss=_$7 30=$210Change in total revenue Loss _ Gain Total revenue will _.decreaseIf the demand is inelastic,when price decreases and quantity increases,gain in revenue is less than loss in revenue.A decrease in price will lead to _ in total revenue,and vice versa.a decrease Loss in total revenueGain in total revenueInelastic demandElasticity and change in total revenue 10050252010124510QdPrice($)Suppose the price of the good decreases from$5 to$4.What is the effect on total revenue?205425Unitarily elastic demandElasticity and change in total revenue 10050252010124510QdPrice($)DQuantityPrice($)205425Unitarily elastic demandElasticity and change in total revenue DQuantityPrice($)Loss in revenueGain in revenue _ units are sold at$1 less.20 Loss=_$1 20=$20 _ more units are sold at$4.5 Loss=_$4 5=$20Change in total revenue Loss _ Gain=Total revenue will _.remain the sameIf the demand is unitarily elastic,when price decreases and quantity increases,gain in revenue is equal to loss in revenue.A decrease in price will lead to _ in total revenue,and vice versa.no change Loss in total revenueGain in total revenueElasticity and change in total revenue All rectangles formed on a unitarily elastic demand curve are _.This property is called _.rectangular hyperbolaequal in area205425Unitarily elastic demandDQuantityPrice($)Loss in revenueGain in revenue _ units are sold at$1 less.20 Loss=_$1 20=$20 _ more units are sold at$4.5 Loss=_$4 5=$20Change in total revenue Loss _ Gain=Total revenue will _.remain the sameLoss in total revenueGain in total revenuePrice Quantity Total Revenue價格價格 數量數量 總收益總收益 Elastic具彈性具彈性Inelastic欠彈性欠彈性Price Quantity Total Revenue價格價格 數量數量 總收益總收益 Elastic具彈性具彈性Inelastic欠彈性欠彈性Price Quantity Total Revenue價格價格 數量數量 總收益總收益 Elastic具彈性具彈性Inelastic欠彈性欠彈性Elasticity of demand can affect the amount of tax shared by consumers and producers.需求彈性可以影響由消費者負擔的稅額需求彈性可以影響由消費者負擔的稅額和生產者負擔的稅額。和生產者負擔的稅額。Elasticity of Demand and Tax Burden需求彈性和稅額負擔需求彈性和稅額負擔total tax paid by producers 生產者生產者支付的總稅額支付的總稅額total tax paid by consumers 消費消費者者支付的總稅額支付的總稅額Q1P1PoQoS1PQ0unit tax單位單位稅稅DS0If demand is inelastic,equilibrium price increases greatly.Consumers share a greater tax burden.Producers share a smaller tax burden.如果需求欠彈性，均衡價格大幅增加，如果需求欠彈性，均衡價格大幅增加，消費者要負擔較大量稅額，生產者負擔消費者要負擔較大量稅額，生產者負擔較少量稅額。較少量稅額。total tax paid by producers 生產者生產者支付的總稅額支付的總稅額total tax paid by consumers 消費消費者者支付的總稅額支付的總稅額Q1P1DS0S1PoQounit tax單位單位稅稅PQ0If demand is elastic,equilibrium price increases slightly.Consumers share a smaller tax burden.Producers share a greater tax burden.如果需求具彈性，均衡價格輕微增加，如果需求具彈性，均衡價格輕微增加，消費者負擔較少量稅額，生產者要負擔消費者負擔較少量稅額，生產者要負擔較大量稅額。較大量稅額。Elasticity of supply 供應供應彈性彈性Elasticity of Supply供應彈性供應彈性percentage change in quantity supplied 供應數量的轉變百分比供應數量的轉變百分比percentage change in price價格的的轉變百分比價格的的轉變百分比=Types of Elasticity of Supply 供應彈性的種類供應彈性的種類Unitary Elastic 單一彈性單一彈性Relatively Elastic 相對具相對具彈性彈性Relatively Inelastic 相對欠相對欠彈性彈性Perfectly Elastic 絕對具絕對具彈性彈性Perfectly Inelastic 絕對絕對欠彈性欠彈性PQ0Unitary Elastic 單一彈性單一彈性Elasticity of supply 供應彈性供應彈性=1SPQ0Unitary Elastic 單一彈性單一彈性Elasticity of supply 供應彈性供應彈性=1SPQ0Relatively Elastic 相對具相對具彈性彈性Elasticity of supply 供應彈性供應彈性 1SPQ0Relatively Elastic 相對具相對具彈性彈性Elasticity of supply 供應彈性供應彈性 1SPQ0Relatively Inelastic 相對欠相對欠彈性彈性Elasticity of supply 供應彈性供應彈性 1SPQ0Relatively Inelastic 相對欠相對欠彈性彈性Elasticity of supply 供應彈性供應彈性 1SPQ0Perfectly Elastic 絕對具絕對具彈性彈性Elasticity of supply 供應彈性供應彈性=SPQ0Perfectly Inelastic 絕對欠絕對欠彈性彈性Elasticity of supply 供應彈性供應彈性=0S1)Time factor 時間因素時間因素2)Production method 生產方法生產方法3)Mobility of factors 生生產產因因素素的的流流動動性性4)Ease of entry 供給者加入工業的難度供給者加入工業的難度Factors Affecting the Elasticity of Supply影響供應彈性的因素影響供應彈性的因素The EndThe End完完