微观经济学课件D讲义资料

Own-Price Elasticity of
p1Demandp1
slope
10 = - 2
10
slope = - 0.2
5
X1*
50 X1*
In which case is the quantity demanded X1* more sensitive to changes to p1?
Own-Price Elasticity of
From Individual to Market Demand F• Wunhecntaioll ncosnsumers are price-
takers, the market demand function for commodity j is
X j(p 1 ,p 2 ,m 1 , ,m n ) n x * ji(p 1 ,p 2 ,m i).
respect toxv,ayria% % blexyY.is
Economic Applications o• Ef cEonlaomstisitcsiutsye elasticities to
measure the sensitivity of
• quantity demanded of commodity i with respect to the price of commodity i (own-price elasticity of demand)
• and many, many others.
Own-Price Elasticity of Demand
• Q: Why not use a demand curve’s slope to measure the sensitivity of quantity demanded to a change in a commodity’s own price?
20
x
* 1
A
15
x
* 1
B
From Individual to
Market Demand
Fpu1 nctionsp1
p1’
p1’
p1”
p1”
p1
20
x
* 1
A
p1’
15
x
* 1
B
x*1AxB 1
From Individual to
Market Demand
Fpu1 nctionsp1
p1’
p1’
p1Demandp1
slope
10 = - 2
10
slope = - 0.2
5
X1*
50 X1*
In which case is the quantity demanded X1* more sensitive to changes to p1?
Own-Price Elasticity of
p1D1e0m-paacknsdp1
slope
10 = - 2
10
Single Units
slope = - 0.2
5
X1*
50 X1*
In which case is the quantity demanded X1* more sensitive to changes to p1?
Own-Price Elasticity of
p1D1e0m-paacknsdp1
i 1
• If all consumers are identical thenX j(p 1 ,p 2 ,M ) n x * j(p 1 ,p 2 ,m )
where M = nm.
From Individual to
Market Demand
Fpu1 nctionsp1
p1’
p1’
p1”
p1”
p1”
p1”
p1
20
xFra Baidu bibliotek
* 1
A
p1’ p1”
15
x
* 1
B
x*1AxB 1
From Individual to
Market Demand
Fpu1 nctionsp1
p1’
p1’
p1”
p1”
p1
20
x
* 1
A
15
x
* 1
B
p1’
The “horizontal sum”
p1”
of the demand curves
• quantity supplied of commodity i with respect to the price of commodity i (own-price elasticity of supply)
Economic Applications of Elasticity
• quantity supplied of commodity i with respect to the wage rate (elasticity of supply with respect to the price of labor)
slope
10 = - 2
10
Single Units
slope = - 0.2
5
X1*
50 X1*
In which case is the quantity demanded
X1* more sensitive to changes to p1? It is the same in both cases.
of individuals A and B.
35 x*1AxB 1
Elasticities
• Elasticity measures the “sensitivity” of one variable with respect to another.
• The elasticity of variable X with
Chapter Fifteen
Market Demand
From Individual to Market Demand Functions
• Think of an economy containing n consumers, denoted by i = 1, … ,n.
• Cfuonncstuiomnefx ro*jiri’(sp c1oo,p mrd2m,im noia)driytydej misand
• demand for commodity i with respect to the price of commodity j (cross-price elasticity of demand).
Economic Applications of Elasticity
• demand for commodity i with respect to income (income elasticity of demand)