18张图玩转AP微观经济学-学术葩AP学习中心
微观经济学从考试的角度来讲主要考察对图形的理解炙炎梵天剑 。重点理解图形每个交点和面积的含义，和每条线段形状的由来。为了同学们方便记忆考试，以下内容以英文写就哈！
1. Demand and Supply

Intersecting point:
A: market equilibrium where at the equilibrium price quantity demanded equals the quantity supplied.
Shapes of curves:
Downward sloping of demand curve:
a.law of diminishing marginal Utility
b.income effect and substitution effect (law of demand)
Upward sloping of supply curve:
supply curve is the marginal cost curve above average variable cost
Tips:
distinguish movement of points from shifts of curves. only the changes in price of the product causes the point to move along demand or supply curve. except from price, other determinants, such as costs of raw of materials, income, preference哟组词 , shift the whole curves. a rightward shift means an increase, while leftward a decrease.
Areas:
Consumer surplus: accumulated satisfaction gained from paying less than what consumers are prepared to pay after consuming Qe units;
Producer surplus: accumulated profits gained from receiving more than additional cost incurred by every unit.
2. Ceiling Price Control (maximum price control)

Intersecting points:
C: equilibrium without price control
A: quantity supplied after effective price ceiling (which must be below equilibrium price)
B: quantity demanded shortage
Areas:
consumer surplus before control = a+b
consumer surplus after control = a+c
producer surplus before control = c+d+e
producer surplus after control = e
deadweight loss = b+d
3. Floor Price Control (minimum price control)

Intersecting points:
C: equilibrium without price control
B: quantity supplied
A: quantity demanded surplus
Areas:
consumer surplus before control = a+b+c
consumer surplus after control = a
Producer surplus before control = e+f
producer surplus after control = b+c+d+e+f
4. Per Unit Tax

Intersecting points:
B: equilibrium without tax
A: equilibrium with tax
C: price received by producer after tax
Areas:
producer surplus after tax=f
consumer surplus after tax=a
government tax revenue=b+d t
tax burden on producer=d
tax burden on consumer=b
deadweight loss=c+e
Tips:
If demand is more elastic than supply, producer will share more tax burden
If demand is less elastic than demand, consumer will share more tax burden
If a lump sum tax is imposed on producer, then it has no effect on equilibrium price and quantity.
5. Per Unit Subsidy to Producer

Intersecting points:
B: equilibrium without subsidy
A: equilibrium with subsidy
Areas:
producer surplus after subsidy = g+f+h
consumer surplus after subsidy = a+b+c+d
subsidy from government = distance between supply before and after subsidy multiplied by Qs
Tips:
If a lump sum subsidy is granted to producer旺家小农女 , then it has no effect on equilibrium price and quantity.
If per unit subsidy is granted to consumer, then it will shift demand curve rightward.
6. Tariff

Intersecting points:
A: domestic quantity demanded before tariff
B: domestic quantity supplied before tariff
Difference between A and B: imports before tariff
C: domestic quantity demanded after tariff
E: domestic quantity supplied after tariff
Difference between C and E: imports after tariff
Shapes of curve:
world supply is horizontal恋爱告急 , assuming the world producers can provide infinite amount of goods to the specific country under the world price.
Areas:
consumer surplus before tariff = a+b+e+c+d+m
consumer surplus after tariff = a+d
domestic producer surplus before tariff = g
domestic producer surplus after tariff = g+b
foreign producer surplus before and after tariff = 0
government tariff revenue = c
deadweight loss = e+m
7. Quota

Intersecting points:
A: domestic quantity demanded before quota
B: domestic quantity supplied before quota
Difference between A and B: imports before quota
C: domestic quantity demanded after quota
E: domestic quantity supplied after quota
Difference between C and E: quota
Shapes of curve:
orld supply is horizontal, assuming the world producers can provide infinite amount of goods to the specific country under the world price.
Areas:
consumer surplus before quota = a+b+e+c+d+m
consumer surplus after quota = a+d
domestic producer surplus before quota = g
domestic producer surplus after quota = g+b
foreign producer surplus before and after quota = 0
economic rent = c
deadweight loss = e+m
8. Labor Output Curves

Intersecting point:
A: maximum AP (MP=AP)
Shapes of curves:
MP’s increasing part is due to the increasing marginal returns to labor and the diminishing part is due to the constraint of fixed factors in the short run.
AP is increasing when MP is greater than AP, and decreasing when AP greater than MP.
9. Cost Curves

Intersecting points:
A: minimum ATC
B: minimum AVC
Shapes of curves:
MC=wage/MP, so it is the inverted shape of MP,
AVC=wage/AP, so it is the inverted shape of AP.
AFC is always decreasing as AFC=TFC/Q
AVC is U shaped as when MC is less than AVC郑仲茵 , AVC is decreasing骑士风云录 , increasing when MC greater than AVC.
ATC is U shaped as initially both AVC and AFC are decreasing and eventually AVC is rising faster than AFC ‘s decreasing rate.
Tips:
marginal cost is independent of fixed costs ,and dependent on variable costs. The difference between ATC and AVC can’t rise as output increases.
10. Perfect Competition Market

Intersecting points:
A: market equilibrium and allocative efficient(P=MC)
B: profit maximizing: MR=MC,
Normal profit: P=ATC
productive efficient: MC=ATC (minimum ATC)
Shapes of curve:
demand faced by individual firm is horizontal, which means producer is a price taker and consumers’ responsiveness to individual firm’s price changes is perfectly elastic.
An individual producer can sell infinite goods at market price.
Areas:
abnormal profit, normal profit, loss
Tips:
in the short run, there are three possible situations for a competitive producer, normal, abnormal, and loss, while in the long run ,there is only normal profit.
11. Monopoly

Intersecting points:
B: profit maximizing point: MR=MC
E: ATC pricing (to regulate monopoly to set a price which earns normal profit P=ATC)
A: allocative efficient point (P=MC)
C: productive efficient point (MC=ATC)
Shapes of curve:
MR is under demand curve as the monopoly is a price maker which means MR<price.
Areas:
consumer surplus =a
deadweight loss=e
abnormal profit=green area
Tips:
monopoly is allocative inefficient and productive inefficient
12. Monopolistic Competition

Intersecting points:
C: allocative efficient(P=MC)
A: profit maximizing: MR=MC, Normal profit: P=ATC
B: productive efficient point: MC=ATC (minimum ATC)
Shapes of curve:
demand curve faced by individual firm is highly elastic, as individual firm’s product is highly substitutable.
Areas:
normal profit=0
deadweight loss=e
in the short run神华招标网 , there are three possible situations方便面雪糕 , normal, abnormal ,季天笙 and loss, while in the long run ,there is only normal profit.
13. Non-Collusive Oligopoly

Shapes of curves:
demand curve faced by individual firm is kinked, as a rise in price will not be matched by competitors while a cut will be.
14. Cartel

Intersecting points:
A: joint profit maximizing point
B: individual member’s quota
Shapes of curves:
price is fixed under cartel, so an individual member is a price taker which means MR=Price.
Areas:
individual firm’s allocated profits = white shaded area
Tips:
the whole industry acts like a monopoly, but every member has incentive to cheat when others obey the rule.
15. Purely Competitive Labor Market

Intersecting points:
B: market equilibrium
A: individual firms profit maximizing employment of labor(MRP=MFC)
Shapes of curve:
supply of labor faced by individual firm is perfectly elastic as it is a wage taker and it can employ as many workers as it wants at market wage.
16. Monopsony

Intersecting points:
A: profit maximizing employment of labor (MRP=MFC)
B: purely competitive labor market equilibrium (D=S)
Shapes of curves:
MFC is above supply of labor which means MFC>wage
17. Positive Externality

Intersecting points:
B: social optimal points (MSB=MSC)
A: market equilibrium (MPB=MPC)
Shapes of curves:
MSB is above MPB as acts generate positive benefits to a third party who is not involved in the action.
Areas:
deadweight loss=yellow shaded area
Tips:
to correct positive externality, a per unit subsidy should be granted to producer or consumer to increase the market output. remember not lump sum subsidy!
18. Negative Externality

Intersecting points:
A: social optimal points (MSB=MSC);
B: market equilibrium (MPB=MPC)
Shapes of curves:
MSC is above MPC as acts generate additional cost to a third party who is not involved in the action.
Areas:
deadweight loss=red shade area
Tips:
to correct negative externality, a per unit tax should be imposed on producer or consumer to decrease the market output. remember not lump sum tax粘竿处 !
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