lecture02 Supply and demand model 平狄克微观经济学英文课件
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平狄克 微观经济学 第七版 课件 第二章
– the direction of change in quantity with price – how much the quantity changes with a change in price
• in amount, or in proportion
Price Elasticity of Demand
19 20
%∆QS ∆QS / QS = % ∆P ∆P / P
Gasoline: SR and LR Demand Curves
Price
Short-Run and Long-Run Supply Elasticity
• For most goods and services,
– long-run price elasticity of supply is greater than short-run price elasticity of supply – firms can better adjust their capacity (“fixed” inputs) and method of production if given sufficient time
• Income elasticity also varies with the amount of time consumers have to respond to an income change
– for most goods and services, income elasticity is larger in the long run – when income changes, it takes time to adjust spending patterns
• in amount, or in proportion
Price Elasticity of Demand
19 20
%∆QS ∆QS / QS = % ∆P ∆P / P
Gasoline: SR and LR Demand Curves
Price
Short-Run and Long-Run Supply Elasticity
• For most goods and services,
– long-run price elasticity of supply is greater than short-run price elasticity of supply – firms can better adjust their capacity (“fixed” inputs) and method of production if given sufficient time
• Income elasticity also varies with the amount of time consumers have to respond to an income change
– for most goods and services, income elasticity is larger in the long run – when income changes, it takes time to adjust spending patterns
平狄克中级微观经济学讲义(厦门大学范文
平狄克中级微观经济学讲义（厦门大学王瑞芳）微观经济学 (平狄克，鲁宾费尔德，第四版)LECTURE 2 导论一、前言微观经济学的研究范围微观经济学的研究范围包括:微观主体行为：消费者（如何）选择买（什么）；生产者（如何）选择生产（什么）.市场：消费者和生产者的联系纽带。
而宏观经济学主要考察的是宏观课题如经济增长、通货膨胀和失业率等。
微观经济学是宏观经济学的基础。
微观经济学的要旨资源的稀缺性决定了我们不总是能获得我们想要的，这就要求对稀缺性资源进行合理配置，配置可以通过市场、也可以通过计划实现，微观经济学的目的不在于确定哪种方式更好，而是给衡量配置方式优劣一个标尺。
几个相关概念的比较理论VS模型；实证VS规范；市场VS行业；竞争性市场VS非竞争性市场；市场的内涵VS市场的外延；市场的地理边界VS市场的产品范围；名义价格VS实际价格二、需求和供给的基本原理需求与供给供给供给曲线显示在其他外部条件保持不变的情况下，在一个既定价格下生产者愿意出售的产品数量（价格-数量关系）；它与价格成正向相关关系。
非价格的供给决定因素包括：生产成本（劳动力、资本、原材料）。
供给曲线由非价格决定因素决定，一旦这些因素发生变动，整条曲线都将发生移动；在非价格决定因素不变的情况下，价格发生变动带来的供给数量的变动由曲线上点的移动来体现，此时供给曲线保持不变，改变的是实际的落点。
需求需求曲线显示在非价格因素保持不变的情况下，每单位产品售价发生的变化导致他愿意购买的数量的变化（价格数量关系）；它与价格成反向相关关系。
非价格的需求决定因素包括：收入、消费者品味,相关商品价格（互补品、竞争品）需求曲线的变动和需求曲线上点的变动规律同供给曲线。
均衡均衡（市场出清）：供给曲线与需求曲线相交。
图PP11;市场机制：图PP12,13供给和需求相互作用决定市场出清价格；一旦价格偏离均衡，则市场将通过价格变动自发调整，减轻需求方或供给方的过剩或不足，从而实现重新均衡；要使市场机制有效，市场必须是竞争性的。
微观经济学平狄克
（短期：生产引导消费 长期：消费引导生产，有需求的产品才能生产——需求决定供给）
1篇 导论/ 2章 供给和需求/ 2.1 供给和需求
⑴ 需求(demand)
条件1：愿意、欲望(willing, desires)
[清]胡澹庵《解人颐》一书中收录的《不知足》诗： 终日奔波只为饥，方才一饱便思衣。衣食两般皆具足，又想娇容美貌妻。 娶得美妻生下子，恨无田地少根基。买得田园多广阔，出入无船少马骑。 槽头拴了骡和马，叹无官职被人欺。县丞主薄还嫌小，又要朝中挂紫衣。
5.00P
4.00 3.00
3
4.00
4
3.00
一般向右下方倾斜 (downward-sloping)
2.00
6
2.00
1.00
9
需求公式
Qd = D(P) eg. Qd = 7 - P
1.00
D
0.00
Qd
0 1 2 3 4 5 6 7 8 9 10
1篇 导论/ 2章 供给和需求/ 2.1 供给和需求
供求均衡(equilibrium)
供给曲线&需求曲线相交的点：市场的均衡点
价 格 ( P ) 需 求 ( Q d ) 价 格 ( P ) 供 给 ( Q d ) 5.00P
S
元
个
元
个
4.00
3
4.00
9
4.00
3.00
4
3.00
8
3.00
2.00
6
2.00
6 Pe 2.00
1.00
9
1.00
3
1.00
若要世人心里足，除是南柯一梦西。
Eg.马斯洛的需求层次论(Maslow’s hierarchy of needs) 自我实现
1篇 导论/ 2章 供给和需求/ 2.1 供给和需求
⑴ 需求(demand)
条件1：愿意、欲望(willing, desires)
[清]胡澹庵《解人颐》一书中收录的《不知足》诗： 终日奔波只为饥，方才一饱便思衣。衣食两般皆具足，又想娇容美貌妻。 娶得美妻生下子，恨无田地少根基。买得田园多广阔，出入无船少马骑。 槽头拴了骡和马，叹无官职被人欺。县丞主薄还嫌小，又要朝中挂紫衣。
5.00P
4.00 3.00
3
4.00
4
3.00
一般向右下方倾斜 (downward-sloping)
2.00
6
2.00
1.00
9
需求公式
Qd = D(P) eg. Qd = 7 - P
1.00
D
0.00
Qd
0 1 2 3 4 5 6 7 8 9 10
1篇 导论/ 2章 供给和需求/ 2.1 供给和需求
供求均衡(equilibrium)
供给曲线&需求曲线相交的点：市场的均衡点
价 格 ( P ) 需 求 ( Q d ) 价 格 ( P ) 供 给 ( Q d ) 5.00P
S
元
个
元
个
4.00
3
4.00
9
4.00
3.00
4
3.00
8
3.00
2.00
6
2.00
6 Pe 2.00
1.00
9
1.00
3
1.00
若要世人心里足，除是南柯一梦西。
Eg.马斯洛的需求层次论(Maslow’s hierarchy of needs) 自我实现
平狄克微观经济学第二章
需求函数 QD = QD(P,I,Px,U, PE ,A,T,……) ) 简化为Q 简化为 D = QD(P)
Chapter 2: 供给和需求的基本原理 Slide 4
供给和需求
需求法则
在其他条件不变的情况下, 在其他条件不变的情况下,随着某种商品或劳 务的价格上升(或下降), ),会导致对该商品或 务的价格上升(或下降),会导致对该商品或 劳务的需求量的减少(增加); );也就是商品价 劳务的需求量的减少(增加);也就是商品价 格与其需求量成反比 例外:吉芬商品,炫耀性商品(钻石) 例外:吉芬商品,炫耀性商品(钻石)
奢侈品 必需品
收入弹性
{ <0
>0
正常商品
{ <1
>1
低档商品 劣质品) (劣质品)
Chapter 2: 供给和需求的基本原理
Slide 29
供给和需求的弹性
其他需求弹性
需求的交叉价格弹性
定义: 需求量的相对变化 需求量的相对变化/Y商品价格的相对 定义:X需求量的相对变化 商品价格的相对 变化 EXY =( QX/QX)/(PY/PY) 反映相关商品间的相互影响 EXY >0, 则称Y是X的替代产品 则称 是 的替代产品 则称Y是 的互补产品 EXY <0, 则称 是X的互补产品
The Market for Wheat
Supply (Qs) Demand (QD)
1981 1800 + 240P 3550 - 266P
Equilibrium Price (Qs = QD)
1800+240P = 3550-266P 506P = 1750 P1981 = $3.46/bushel 1,944+207P = 3,244-283P P1998 = $2.65/bushel
平狄克中级微观经济学Ch02_Pindyck
Q1
©2005 Pearson Education, Inc.
Q2
Chapter 2
Quantity
6
The Supply Curve
Other Variables Affecting Supply
Costs of Production
Labor Capital
Raw
Materials
P1 P0
2. 3.
ቤተ መጻሕፍቲ ባይዱ4.
D Q
©2005 Pearson Education, Inc.
D
Q0
Chapter 2
QS
Quantity
19
The Market Mechanism
The market price is below equilibrium:
There is excess demand - shortage Upward pressure on prices Quantity demanded decreases and quantity supplied increases The market adjusts until the new equilibrium is reached
Q1
Q2
Q
8
The Supply Curve
Change in Quantity Supplied
Movement along the curve caused by a change in price
Change in Supply
Shift of the curve caused by a change in something other than the price of the good
平狄克和鲁宾费尔德微观经济学microeconomics rubinfeld pindyck textbook Ch 2
Price
S
P1 P2
D2 Q2 Q1
D1
Quantity of Butter
Figure 2.2.c 3. If a 3-percent increase in the price of corn flakes causes a 6-percent decline in the quantity demanded, what is the elasticity of demand? The elasticity of demand is the percentage change in the quantity demanded divided by 6 2 . the percentage change in the price. The elasticity of demand for corn flakes is 3 This is equivalent to saying that a 1% increase in price leads to a 2% decrease in quantity demanded. This is in the elastic region of the demand curve, where the elasticity of demand exceeds -1.0. 4. Explain the difference between a shift in the supply curve and a movement along the supply curve. A movement along the supply curve is caused by a change in the price or the quantity of the good, since these are the variables on the axes. A shift of the supply curve is caused by any other relevant variable that causes a change in the quantity supplied at any given price. Some examples are changes in production costs and an increase in the number of firms supplying the product. 5. Explain why for many goods, the long-run price elasticity of supply is larger than the short-run elasticity. The elasticity of supply is the percentage change in the quantity supplied divided by the percentage change in price. An increase in price induces an increase in the quantity supplied by firms. Some firms in some markets may respond quickly and cheaply to price changes. However, other firms may be constrained by their production capacity in the short run. The firms with short-run capacity constraints will have a short-run supply elasticity that is less elastic. However, in the long run all firms can increase their scale of production and thus have a larger long-run price elasticity.
平狄克微观经济学课件(英文)02
4 of 53
2.1
SUPPLY AND DEMAND
The Supply Curve
The supply curve is thus a relationship between the quantity supplied and the price. We can write this relationship as an equation: QS = QS(P)
Chapter 2 Supply and Demand
© 2008 Prentice Hall Business Publishing • Microeconomics • Pindyck/Rubinfeld, 7e.
5 of 53
2.1
SUPPLY AND DEMAND
The Demand Curve
© 2008 Prentice Hall Business Publishing • Microeconomics • Pindyck/Rubinfeld, 7e.
2 of 53
The Basics of Supply and Demand
Supply-demand analysis is a fundamental and powerful tool that can be applied to a wide variety of interesting and important problems. To name a few: • Understanding and predicting how changing world economic conditions affect market price and production • Evaluating the impact of government price controls, minimum wages, price supports, and production incentives
2.1
SUPPLY AND DEMAND
The Supply Curve
The supply curve is thus a relationship between the quantity supplied and the price. We can write this relationship as an equation: QS = QS(P)
Chapter 2 Supply and Demand
© 2008 Prentice Hall Business Publishing • Microeconomics • Pindyck/Rubinfeld, 7e.
5 of 53
2.1
SUPPLY AND DEMAND
The Demand Curve
© 2008 Prentice Hall Business Publishing • Microeconomics • Pindyck/Rubinfeld, 7e.
2 of 53
The Basics of Supply and Demand
Supply-demand analysis is a fundamental and powerful tool that can be applied to a wide variety of interesting and important problems. To name a few: • Understanding and predicting how changing world economic conditions affect market price and production • Evaluating the impact of government price controls, minimum wages, price supports, and production incentives
平狄克 中级微观经济学第一章课后练习答案_Ch01
Oklahoma and New Jersey represent separate geographic markets for gasoline because of high transportation costs.There would be an opportunity for arbitrage if transportation costs were less
In general, the first class is a good time to pique student interest in the course.It is also a good time to tell students that they need to work hard to learn how to do economic analysis, and that memorization alone will not get them through the course.Students must learn to think like economists, so encourage them to work lots of problems.Also encourage them to draw graphs neatly and large enough to make them easy to interpret.It always amazes me to see the tiny, poorly drawn graphs some students produce.It is no wonder their answers are often incorrect.You might even suggest they bring a small ruler and colored pencils to class as they can draw good diagrams.
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Key issues
• demand • supply • market equilibrium • shocking the equilibrium • effects of government interventions • when to use supply and demand model
• change in any other factor besides the price causes a shift of the demand curve
Variable definitions
• Q = quantity of pork demanded (million kg per year)
curves: Q1 = D1(P) Q2 = D2(P) • total quantity demanded = horizontal sum of quantity each consumer demands at each given price: Q = Q1 + Q2 = D1(P) + D2(P)
• P = price of pork ($ per kg) • Pb = price of beef ($ per kg) • Pc = price of poultry ($ per kg) • I = income of consumers (thousand $)
Demand function
quantity demanded (holding other factors constant) • one of the most important empirical finding in economics
Demand effects of other factors
• change in any factor other than the price of the good causes a shift of the deng the demand curve)
Demand Curve for Canadian Pork
Effect of price changes
• movement along the demand curve • demand curve is a concise summary of the
answer to the question:
Supply and demand model
• most widely-used economic model • testable (like all good theories) • describes how consumers and suppliers
interact in a market to determine quantity of a good sold and its price
beef causes some people to switch from beef to pork
A Shift of the Pork Demand Curve
Summary
• change in the price of a good causes a movement along a demand curve
• note: quantity demanded of a good or service can exceed quantity sold (or vice versa)
• strange demand curve convention: price is on the vertical axis
Demand curve
• shows quantity demanded—largest quantity that consumers are willing to buy—at each price, holding constant other factors that affect purchases
To use supply and demand model
• you need to determine
• buyers' behavior • sellers' behavior • how they interact
• know whether the model is: applicable to the market under examination
what happens to the quantity demanded as the price changes, holding all other factors constant?
Law of demand
• demand curves slope down • a drop in price results in an increase in
• general function Q = D(P, Pb, Pc, I)
• specific (linear) pork demand function Q = 171 – 20P + 20Pb + 3Pc + 2I
Summing demand curves
• total demand is sum of demand for all consumers • suppose there are 2 consumers with demand
• this shift of the demand curve is a trick to avoid drawing 3D diagrams
Effect on pork demand of a rise in price of beef
• beef is a substitute for pork • at a given price of pork, a rise in the price of
• demand • supply • market equilibrium • shocking the equilibrium • effects of government interventions • when to use supply and demand model
• change in any other factor besides the price causes a shift of the demand curve
Variable definitions
• Q = quantity of pork demanded (million kg per year)
curves: Q1 = D1(P) Q2 = D2(P) • total quantity demanded = horizontal sum of quantity each consumer demands at each given price: Q = Q1 + Q2 = D1(P) + D2(P)
• P = price of pork ($ per kg) • Pb = price of beef ($ per kg) • Pc = price of poultry ($ per kg) • I = income of consumers (thousand $)
Demand function
quantity demanded (holding other factors constant) • one of the most important empirical finding in economics
Demand effects of other factors
• change in any factor other than the price of the good causes a shift of the deng the demand curve)
Demand Curve for Canadian Pork
Effect of price changes
• movement along the demand curve • demand curve is a concise summary of the
answer to the question:
Supply and demand model
• most widely-used economic model • testable (like all good theories) • describes how consumers and suppliers
interact in a market to determine quantity of a good sold and its price
beef causes some people to switch from beef to pork
A Shift of the Pork Demand Curve
Summary
• change in the price of a good causes a movement along a demand curve
• note: quantity demanded of a good or service can exceed quantity sold (or vice versa)
• strange demand curve convention: price is on the vertical axis
Demand curve
• shows quantity demanded—largest quantity that consumers are willing to buy—at each price, holding constant other factors that affect purchases
To use supply and demand model
• you need to determine
• buyers' behavior • sellers' behavior • how they interact
• know whether the model is: applicable to the market under examination
what happens to the quantity demanded as the price changes, holding all other factors constant?
Law of demand
• demand curves slope down • a drop in price results in an increase in
• general function Q = D(P, Pb, Pc, I)
• specific (linear) pork demand function Q = 171 – 20P + 20Pb + 3Pc + 2I
Summing demand curves
• total demand is sum of demand for all consumers • suppose there are 2 consumers with demand
• this shift of the demand curve is a trick to avoid drawing 3D diagrams
Effect on pork demand of a rise in price of beef
• beef is a substitute for pork • at a given price of pork, a rise in the price of