需求价格弹性教案

需求价格弹性教案 第二章 市场运行:需求与供给 第五节 需求价格弹性 (第一部分2学时) 【教学目的】:让学生理解弹性、需求价格弹性的含义;掌握需求价格弹性的计算。 【前课回顾】:上节课讲了需求与供给的均衡:在市场条件下，需求和供给两个力量在相互作用的情况下会产生均衡的价格和数量，即市场均衡(Market Equilibrium)。市场均衡出现在需求曲线和供给曲线的交点上。在该点上消费者愿意购买商品的数量正好等于生产者愿意生产商品的数量。但是该均衡是在不断变化着的，变化后又会达到新的均衡。(5分钟) 【新课导入】:在现实生活中我们会经常见到一些现象，如商家通过降低价格的方法来增加销售量从而增加销售收入和提高利润水平的做法称为“薄利多销”。还有，如农业大丰收，农产品储量丰富，农产品的价格下降，农民虽然多产了粮却反而收入下降的现象叫做“谷贱伤农”。上述这两种现象当中到底蕴含着怎样的经济学原理呢,(5分钟) 【授课内容】: 一、需求价格弹性 (一)弹性(Elasticity)源于物理学，指的是某一物体对外部力量的的敏感程度或反应程度。 表示因变量对自变量变化的敏感程度或反应程度。 公式: YY,,y21 因变量的相对变化,yXYYE=,,,, XXx,,自变量的相对变化,xY21 XX (其中:E是弹性系数，X是自变量，Y是因变量) 含义:自变量每变化一个百分点时，因变量会变化的百分点，这是一个比值，表示了两个变量各自变化量的比例关系，与其变量的计量单位无关。 [例1]: “基础设施投资增加1%，区域经济的GDP将被拉动提升1%”(出自世界Stems, root cause mechanical damage, looping root amputation at the wound to prevent infection. (3) category tree seedlings: a spindle should have a uniform distribution of main branches, branches, trunk diameter above 3.0CM; make trees of broadleaved trees branch height should be relatively consistent, with 3-5 main branch, trunk diameter of not less than 4cm, branch point is not less than 2.5M; coniferous trees with the spindle, there are primary. (4) shrubs class seedlings: tufted type shrubs requirements irrigation bundle full, and main collateral distribution uniform, and main branch number not less than 5 branch, at least has 3 branch above irrigation high reached provides standard; creeping type shrubs requirements at least has 3 branch above main branch reached provides standard length; vine health seedlings, and should points branch uniform, and main article number 5 branch above, and main article diameter 1.0CM above; going it alone type shrubs requirements with trunk, and points branch uniform, base diameter in 2.0CM above; hedge with shrubs requirements irrigation bundle full, and points branch uniform, and dry lower leaves no bare, More than 2 years old. All plants are shrubs should meet the specifications. (5) the solitary trees should be selected single planting ornamental tree is beautiful, high ornamental value of individual plants. (6) design should be selected when the bushes planted plant specifications, flowering shrubs such as rhododendron plants should select color uniform varieties, planting interval and density. 4, seedling planting project plants should be located according to the drawings, and with reference to the national standard and suitable to avoid lines, planting pits should be greater than the minimum thickness requirements, planting soil backfill compaction in layers to ensure that plants are firmly rooted in the ground, supported by large-size seedlingshe primary analysis of soil physical and chemical properties, such as pests, disinfection, pest control in advance. Garden plant growth by required of minimum planting soil thickness should meet Xia table (construction figure Shang indicate of except) vegetation type herb flower lawn to was small shrubs big shrubs shallow root trees deep root trees soil thickness 30 (CM) 30 (CM) 45 (CM) 60 (CM) 90 (CM) 120 (CM) planting soil should selection for plant growth of selective soil, as humic acid soil, and lawn fertilizer, and peat soil, and pH 5.5~7.0, humidity 30~70%, completely loose, Lawn planting soil roughness (soil surface should be lower than teeth pond 2~5cm). 2, planting garden of foundation engineering projects from planning to the construction stage, focus on after completion of landscaping, the overall goal is to create a good living environment for plants, create a garden and green space. Plant engineering of the project was to create the basis for plant growth, soil, it can be said is the garden project, is one of the most important works. Also planted phase of this project must be carried out by the local soil improvement project. 3, seedling selection requirements: (1) engineering seedling selection of cooked goods, provisions relating to plant size. Plant procurement specifications can be large, so as to achieve ecological effect in a short time. Seedlings should have ... Strong, lush, Crown-shaped full, normal color, root system, pest and disease-free. (2) the project should have growth robust, lush, Crown-shaped full, normal color, root system, pest and disease-free. 银行:《1994年世界发展》) 在上述的弹性系数是1。 (二)、需求价格弹性 是指某商品的需求量对其价格变化的敏感程度或反应程度。 即是需求量变化的百分比与价格变化的百分比之比。 公式: ,Q ,QPQ E,,=d,P,PQ P ——需求价格弹性系数 Ed Q——需求量 ——需求变化量 ,Q ,PP——价格 ——价格变化量 {注意}: 1、我们将所有的百分比变动视为正数，从而去掉数值中的负号。这意味着尽管有反方向变动的可能，但是需求价格弹性均不小于零。同样，当说到某产品的需求价格弹性大即是指其绝对值大。 2、弹性定义使用的是相对变化的百分比，而非实际变化量，并与变量单位无关。 3、计算公式中的“价格”和“需求量”，通常采用平均值计算。 即中点法: ,Q ,QQQ，[()2]Q12,,, 弧弹性 E,=d,P,PPP，[()2]12P ,P当趋于无穷小时，我们可以计算某一点处的需求价格弹性，用“微积分”得出“点弹性”。 公式: dQQdQP= E,,ddPPdPQ (三)、需求价格弹性的计算 1、中点法 Stems, root cause mechanical damage, looping root amputation at the wound to prevent infection. (3) category tree seedlings: a spindle should have a uniform distribution of main branches, branches, trunk diameter above 3.0CM; make trees of broadleaved trees branch height should be relatively consistent, with 3-5 main branch, trunk diameter of not less than 4cm, branch point is not less than 2.5M; coniferous trees with the spindle, there are primary. (4) shrubs class seedlings: tufted type shrubs requirements irrigation bundle full, and main collateral distribution uniform, and main branch number not less than 5 branch, at least has 3 branch above irrigation high reached provides standard; creeping type shrubs requirements at least has 3 branch above main branch reached provides standard length; vine health seedlings, and should points branch uniform, and main article number 5 branch above, and main article diameter 1.0CM above; going it alone type shrubs requirements with trunk, and points branch uniform, base diameter in 2.0CM above; hedge with shrubs requirements irrigation bundle full, and points branch uniform, and dry lower leaves no bare, More than 2 years old. All plants are shrubs should meet the specifications. (5) the solitary trees should be selected single planting ornamental tree is beautiful, high ornamental value of individual plants. (6) design should be selected when the bushes planted plant specifications, flowering shrubs such as rhododendron plants should select color uniform varieties, planting interval and density. 4, seedling planting project plants should be located according to the drawings, and with reference to the national standard and suitable to avoid lines, planting pits should be greater than the minimum thickness requirements, planting soil backfill compaction in layers to ensure that plants are firmly rooted in the ground, supported by large-size seedlingshe primary analysis of soil physical and chemical properties, such as pests, disinfection, pest control in advance. Garden plant growth by required of minimum planting soil thickness should meet Xia table (construction figure Shang indicate of except) vegetation type herb flower lawn to was small shrubs big shrubs shallow root trees deep root trees soil thickness 30 (CM) 30 (CM) 45 (CM) 60 (CM) 90 (CM) 120 (CM) planting soil should selection for plant growth of selective soil, as humic acid soil, and lawn fertilizer, and peat soil, and pH 5.5~7.0, humidity 30~70%, completely loose, Lawn planting soil roughness (soil surface should be lower than teeth pond 2~5cm). 2, planting garden of foundation engineering projects from planning to the construction stage, focus on after completion of landscaping, the overall goal is to create a good living environment for plants, create a garden and green space. Plant engineering of the project was to create the basis for plant growth, soil, it can be said is the garden project, is one of the most important works. Also planted phase of this project must be carried out by the local soil improvement project. 3, seedling selection requirements: (1) engineering seedling selection of cooked goods, provisions relating to plant size. Plant procurement specifications can be large, so as to achieve ecological effect in a short time. Seedlings should have ... Strong, lush, Crown-shaped full, normal color, root system, pest and disease-free. (2) the project should have growth robust, lush, Crown-shaped full, normal color, root system, pest and disease-free. [例2] 设某商品的需求函数为，请计算当价格从5降到4时的Q,2400400,pd需求价格弹性。 解: 当P=5时， Q,400d1 当P=4时， Q,800d2 ,Q ,QQQ，[()2]400(12002)Q12 E,,,3=d,P1(92),PPP，[()2]12P 2、微积分法 [例3] 设某商品的需求函数为，计算当价格为5时的需求价格弹Q,2400400,pd性。 Q,,，,24004005400d 5dQQ,，,4005 =Ed400dPP 其中的负号已忽略。 3、几何法 (1)、线性需求曲线 设线性需求曲线分别与纵坐标及横坐标相交于A、B两点，令C点为该曲线上任 意一点，求C点的需求价格弹性。 价格P A C ? D曲线 需求B 量Q BCE= dAC Stems, root cause mechanical damage, looping root amputation at the wound to prevent infection. (3) category tree seedlings: a spindle should have a uniform distribution of main branches, branches, trunk diameter above 3.0CM; make trees of broadleaved trees branch height should be relatively consistent, with 3-5 main branch, trunk diameter of not less than 4cm, branch point is not less than 2.5M; coniferous trees with the spindle, there are primary. (4) shrubs class seedlings: tufted type shrubs requirements irrigation bundle full, and main collateral distribution uniform, and main branch number not less than 5 branch, at least has 3 branch above irrigation high reached provides standard; creeping type shrubs requirements at least has 3 branch above main branch reached provides standard length; vine health seedlings, and should points branch uniform, and main article number 5 branch above, and main article diameter 1.0CM above; going it alone type shrubs requirements with trunk, and points branch uniform, base diameter in 2.0CM above; hedge with shrubs requirements irrigation bundle full, and points branch uniform, and dry lower leaves no bare, More than 2 years old. All plants are shrubs should meet the specifications. (5) the solitary trees should be selected single planting ornamental tree is beautiful, high ornamental value of individual plants. (6) design should be selected when the bushes planted plant specifications, flowering shrubs such as rhododendron plants should select color uniform varieties, planting interval and density. 4, seedling planting project plants should be located according to the drawings, and with reference to the national standard and suitable to avoid lines, planting pits should be greater than the minimum thickness requirements, planting soil backfill compaction in layers to ensure that plants are firmly rooted in the ground, supported by large-size seedlingshe primary analysis of soil physical and chemical properties, such as pests, disinfection, pest control in advance. Garden plant growth by required of minimum planting soil thickness should meet Xia table (construction figure Shang indicate of except) vegetation type herb flower lawn to was small shrubs big shrubs shallow root trees deep root trees soil thickness 30 (CM) 30 (CM) 45 (CM) 60 (CM) 90 (CM) 120 (CM) planting soil should selection for plant growth of selective soil, as humic acid soil, and lawn fertilizer, and peat soil, and pH 5.5~7.0, humidity 30~70%, completely loose, Lawn planting soil roughness (soil surface should be lower than teeth pond 2~5cm). 2, planting garden of foundation engineering projects from planning to the construction stage, focus on after completion of landscaping, the overall goal is to create a good living environment for plants, create a garden and green space. Plant engineering of the project was to create the basis for plant growth, soil, it can be said is the garden project, is one of the most important works. Also planted phase of this project must be carried out by the local soil improvement project. 3, seedling selection requirements: (1) engineering seedling selection of cooked goods, provisions relating to plant size. Plant procurement specifications can be large, so as to achieve ecological effect in a short time. Seedlings should have ... Strong, lush, Crown-shaped full, normal color, root system, pest and disease-free. (2) the project should have growth robust, lush, Crown-shaped full, normal color, root system, pest and disease-free. 即线性需求曲线上任意一点的需求价格弹性等于位于该点之下的线段长度与位于改点之上的线段长度的比值。如图可见，需求曲线中点处的需求价格弹性为1，沿着需求曲线从中点处往下移动，弹性越来越小，在B点处，需求价格弹性为0。沿着需求曲线从中点处往上移动，弹性越来越大，在A点处，需求价格弹性为。 ，, (2)、非线性需求曲线 设C为非线性需求曲线上任意一点，过该点作需求曲线的切线，分别与纵坐标及横坐标相交于A、B点，可以得到C点的需求价格弹性为: BCE= dAC 价格P A C ? D曲线 需求量Q B 【教学小结】:通过课堂教学中给出的公式和例举的例，理解和掌握弹性在经济学中的含义，并掌握弹性的计算方法。 弹性是指某一物体对外部力量的反应程度。变量之间存在函数关系，弹性表示因变量对自变量的反应程度。 需求价格弹性是指某种商品的需求量对其价格变化的反应程度，即需求量变化的百分比与价格变化的百分比之比。 计算需求价格弹性的方法有中点法、微积分法和几何法。 【课后作业】: 一、名词解释: 需求价格弹性 Stems, root cause mechanical damage, looping root amputation at the wound to prevent infection. (3) category tree seedlings: a spindle should have a uniform distribution of main branches, branches, trunk diameter above 3.0CM; make trees of broadleaved trees branch height should be relatively consistent, with 3-5 main branch, trunk diameter of not less than 4cm, branch point is not less than 2.5M; coniferous trees with the spindle, there are primary. (4) shrubs class seedlings: tufted type shrubs requirements irrigation bundle full, and main collateral distribution uniform, and main branch number not less than 5 branch, at least has 3 branch above irrigation high reached provides standard; creeping type shrubs requirements at least has 3 branch above main branch reached provides standard length; vine health seedlings, and should points branch uniform, and main article number 5 branch above, and main article diameter 1.0CM above; going it alone type shrubs requirements with trunk, and points branch uniform, base diameter in 2.0CM above; hedge with shrubs requirements irrigation bundle full, and points branch uniform, and dry lower leaves no bare, More than 2 years old. All plants are shrubs should meet the specifications. (5) the solitary trees should be selected single planting ornamental tree is beautiful, high ornamental value of individual plants. (6) design should be selected when the bushes planted plant specifications, flowering shrubs such as rhododendron plants should select color uniform varieties, planting interval and density. 4, seedling planting project plants should be located according to the drawings, and with reference to the national standard and suitable to avoid lines, planting pits should be greater than the minimum thickness requirements, planting soil backfill compaction in layers to ensure that plants are firmly rooted in the ground, supported by large-size seedlingshe primary analysis of soil physical and chemical properties, such as pests, disinfection, pest control in advance. Garden plant growth by required of minimum planting soil thickness should meet Xia table (construction figure Shang indicate of except) vegetation type herb flower lawn to was small shrubs big shrubs shallow root trees deep root trees soil thickness 30 (CM) 30 (CM) 45 (CM) 60 (CM) 90 (CM) 120 (CM) planting soil should selection for plant growth of selective soil, as humic acid soil, and lawn fertilizer, and peat soil, and pH 5.5~7.0, humidity 30~70%, completely loose, Lawn planting soil roughness (soil surface should be lower than teeth pond 2~5cm). 2, planting garden of foundation engineering projects from planning to the construction stage, focus on after completion of landscaping, the overall goal is to create a good living environment for plants, create a garden and green space. Plant engineering of the project was to create the basis for plant growth, soil, it can be said is the garden project, is one of the most important works. Also planted phase of this project must be carried out by the local soil improvement project. 3, seedling selection requirements: (1) engineering seedling selection of cooked goods, provisions relating to plant size. Plant procurement specifications can be large, so as to achieve ecological effect in a short time. Seedlings should have ... Strong, lush, Crown-shaped full, normal color, root system, pest and disease-free. (2) the project should have growth robust, lush, Crown-shaped full, normal color, root system, pest and disease-free. 二、计算题: 1、某商品的价格由24元上涨到30元后，需求量相应减少10%。问该商品 的需求弹性是多少,该商品价格变化对总收益有何影响, 2、求需求函数P=8-0.5Q在价格4~6元之间的弹性 1、解: 价格变化6元，需求量变化10%，其需求价格弹性为: ,Q 10%Q 0.4E,,,d6,P 24P 假设价格上涨前的需求量为Q，则有: 价格上涨前的收益为:24Q 价格上涨后的收益为: 30(110%)300.927，,,，,QQQ可见，价格上涨后的总收益增加了3Q。 2、解: 由需求函数可知: 8,PPQQ,,,,80.5 0.5 可求出价格在4元和6元的需求量分别为: 84,Q,,810.5 86,Q,,420.5 中点法求出4~6元之间的弹性为: ,Q4 ()/25QQ，12/212E,,, d,P23 ()/210/2PP，12 Stems, root cause mechanical damage, looping root amputation at the wound to prevent infection. (3) category tree seedlings: a spindle should have a uniform distribution of main branches, branches, trunk diameter above 3.0CM; make trees of broadleaved trees branch height should be relatively consistent, with 3-5 main branch, trunk diameter of not less than 4cm, branch point is not less than 2.5M; coniferous trees with the spindle, there are primary. (4) shrubs class seedlings: tufted type shrubs requirements irrigation bundle full, and main collateral distribution uniform, and main branch number not less than 5 branch, at least has 3 branch above irrigation high reached provides standard; creeping type shrubs requirements at least has 3 branch above main branch reached provides standard length; vine health seedlings, and should points branch uniform, and main article number 5 branch above, and main article diameter 1.0CM above; going it alone type shrubs requirements with trunk, and points branch uniform, base diameter in 2.0CM above; hedge with shrubs requirements irrigation bundle full, and points branch uniform, and dry lower leaves no bare, More than 2 years old. All plants are shrubs should meet the specifications. (5) the solitary trees should be selected single planting ornamental tree is beautiful, high ornamental value of individual plants. (6) design should be selected when the bushes planted plant specifications, flowering shrubs such as rhododendron plants should select color uniform varieties, planting interval and density. 4, seedling planting project plants should be located according to the drawings, and with reference to the national standard and suitable to avoid lines, planting pits should be greater than the minimum thickness requirements, planting soil backfill compaction in layers to ensure that plants are firmly rooted in the ground, supported by large-size seedlingshe primary analysis of soil physical and chemical properties, such as pests, disinfection, pest control in advance. Garden plant growth by required of minimum planting soil thickness should meet Xia table (construction figure Shang indicate of except) vegetation type herb flower lawn to was small shrubs big shrubs shallow root trees deep root trees soil thickness 30 (CM) 30 (CM) 45 (CM) 60 (CM) 90 (CM) 120 (CM) planting soil should selection for plant growth of selective soil, as humic acid soil, and lawn fertilizer, and peat soil, and pH 5.5~7.0, humidity 30~70%, completely loose, Lawn planting soil roughness (soil surface should be lower than teeth pond 2~5cm). 2, planting garden of foundation engineering projects from planning to the construction stage, focus on after completion of landscaping, the overall goal is to create a good living environment for plants, create a garden and green space. Plant engineering of the project was to create the basis for plant growth, soil, it can be said is the garden project, is one of the most important works. Also planted phase of this project must be carried out by the local soil improvement project. 3, seedling selection requirements: (1) engineering seedling selection of cooked goods, provisions relating to plant size. Plant procurement specifications can be large, so as to achieve ecological effect in a short time. Seedlings should have ... Strong, lush, Crown-shaped full, normal color, root system, pest and disease-free. (2) the project should have growth robust, lush, Crown-shaped full, normal color, root system, pest and disease-free. 山西建筑职业技术学院 周雯雯 Stems, root cause mechanical damage, looping root amputation at the wound to prevent infection. (3) category tree seedlings: a spindle should have a uniform distribution of main branches, branches, trunk diameter above 3.0CM; make trees of broadleaved trees branch height should be relatively consistent, with 3-5 main branch, trunk diameter of not less than 4cm, branch point is not less than 2.5M; coniferous trees with the spindle, there are primary. (4) shrubs class seedlings: tufted type shrubs requirements irrigation bundle full, and main collateral distribution uniform, and main branch number not less than 5 branch, at least has 3 branch above irrigation high reached provides standard; creeping type shrubs requirements at least has 3 branch above main branch reached provides standard length; vine health seedlings, and should points branch uniform, and main article number 5 branch above, and main article diameter 1.0CM above; going it alone type shrubs requirements with trunk, and points branch uniform, base diameter in 2.0CM above; hedge with shrubs requirements irrigation bundle full, and points branch uniform, and dry lower leaves no bare, More than 2 years old. All plants are shrubs should meet the specifications. (5) the solitary trees should be selected single planting ornamental tree is beautiful, high ornamental value of individual plants. (6) design should be selected when the bushes planted plant specifications, flowering shrubs such as rhododendron plants should select color uniform varieties, planting interval and density. 4, seedling planting project plants should be located according to the drawings, and with reference to the national standard and suitable to avoid lines, planting pits should be greater than the minimum thickness requirements, planting soil backfill compaction in layers to ensure that plants are firmly rooted in the ground, supported by large-size seedlingshe primary analysis of soil physical and chemical properties, such as pests, disinfection, pest control in advance. Garden plant growth by required of minimum planting soil thickness should meet Xia table (construction figure Shang indicate of except) vegetation type herb flower lawn to was small shrubs big shrubs shallow root trees deep root trees soil thickness 30 (CM) 30 (CM) 45 (CM) 60 (CM) 90 (CM) 120 (CM) planting soil should selection for plant growth of selective soil, as humic acid soil, and lawn fertilizer, and peat soil, and pH 5.5~7.0, humidity 30~70%, completely loose, Lawn planting soil roughness (soil surface should be lower than teeth pond 2~5cm). 2, planting garden of foundation engineering projects from planning to the construction stage, focus on after completion of landscaping, the overall goal is to create a good living environment for plants, create a garden and green space. Plant engineering of the project was to create the basis for plant growth, soil, it can be said is the garden project, is one of the most important works. Also planted phase of this project must be carried out by the local soil improvement project. 3, seedling selection requirements: (1) engineering seedling selection of cooked goods, provisions relating to plant size. Plant procurement specifications can be large, so as to achieve ecological effect in a short time. Seedlings should have ... Strong, lush, Crown-shaped full, normal color, root system, pest and disease-free. (2) the project should have growth robust, lush, Crown-shaped full, normal color, root system, pest and disease-free.