文档介绍：Chapter Fourteen
Consumer’s Surplus
消费者剩余
Structure
Money equivalent of utility gains to trade
Consumer’s surplus
Changes in consumer’s pensating and equivalent variations
Producer’s surplus
ary Measures of Gains-to-Trade
You can buy as much gasoline as you wish at $1 per gallon once you enter the gasoline market.
Q: What is the most you would pay to enter the market?
A: You would pay up to the dollar value of the gains-to-trade you would enjoy once in the market.
How can such gains-to-trade be measured?
Three such measures are:
Consumer’s Surplus
Equivalent Variation (等价变换), pensating Variation (补偿变换).
Only in one special circumstance do these three measures coincide.
ary Measures of Gains-to-Trade
Reservation Price
Maximum willingness to pay for an additional unit of a good
Two goods: good 1 (x1) and expenditure on others (x2); p2=1
By budget constraint (p1x1+x2=m):
If x1=0, then x2=m
If x1=1, then x2=m-p1
If x1=2, then x2=m-2p1
If x1=3, then x2=m-3p1
Reservation Price
Reservation price for the 1st unit (r1)
u(0, m) = u(1, m-r1)
r1 is the dollar equivalent of the marginal utility of the 1st unit.
Reservation price for the 2nd unit (r2)
u(1, m-r2) = u(2, m-2r2)
r2 is the dollar equivalent of the marginal utility of the 2nd unit.
Reservation price for the 3rd unit (r3)
u(2, m-2r3) = u(2, m-3r3)
Generally, if she already has n-1 gallons of gasoline then rn denotes the most she will pay for an nth gallon.
rn is the dollar equivalent of the marginal utility of the nth gallon.
$ Equivalent Utility Gains
r1 + …+ rn will be the dollar equivalent of the total change to utility from consuming n gallons of gasoline at a price of $0.
$ Equivalent Utility Gains
$ Equivalent Utility Gains
1
2
3
4
5
6
r1
r2
r3
r4
r5
r6
What is the ary value of our consumer’s gain-to-trading in the gasoline market at a price of $pG?
$ Equivalent Utility Gains