范里安中级微观经济学知识点总结
I. Summary
? Marginal analysis:1:Marginal magnitudes=tangentα=slope of TM 2:Average magnitudes=tangentβ=slope of ray
TM??MM<0F.O.C????MM?0?3: Total magnitude max??? TM??MM>0 MIN 4: AM??MM>AM AM??MM
TM
? Budget constraint and indifference curves:
mVertical intersection:
P2P1MX1?P2X2?m
MM(x*) AM(x*) xX2 m/p2 Budget line Slope = -p1/p2 m p1?
PBudget lines: slope=?1
P2 Horizontal intersection:
Budget set m/p1 X1
? Imposing a tax/giving a subsidy; changing income/price. X2
Increasing income Increasing price
m’/p2
m/p2 Budget line
? Indifference curves: cannot cross each other. ? Following are some indifference cur ves.
Goods Slope = - p’1/p2 m/p’1
Slope = - p1/p2 m/p2
Budget m/p1
Goods Bads Bads Neutrals Bads Good1 Goods Goods Good1 Perfect substitutes Good2 y?a bPerfect complement Good2 ? Utility function:?
mv1dx2P??MRS(forgoodone)??1 mv2dx1P2
? Optimal choice: solutions)
MV1MD2MVn??PPPn12p1x1?p2x2?pnxn?m (Interior/boundary/kinky
Graphically, it is the point where budget line and indifferences curves tangent
m X2X1?2x1Luxury goods: >0 2?mNormal goods:
?x1>0 ?m? Inferior goods: X2 Normal Good Necessary goods:
?x1<0 ?m22By income
?x1<0 ?m Ordinary goods: O ?x1?0?pxm ?x1?0?pxSubstitution goods:X1 By price Inferior Good ?x>0 ?PyGiffen goods: X2 Complement goods: Y ?x<0 ?Py
? Perfect complement:
Good1 Ordinary Good
Giffen Good
Budget lines Income offer curve I Engel Curve Slope=1 P1?P2Good1 Perfect complement Good1 Good2 P1 Budget lines Price offer curve Demand Curve Perfect complement X2 Good2 Good1
? Perfect substitutes: Budget lines Income offer curve X1 Slope=Engel Curve I 1 P1X1
X 2 Budget lines Price offer curve X1
? Cobb-Douglas:
X2
Income offer curve
X1
Budget lines
X2 m P 2 Price offer curve bBudget lines a?b*mP 2? Quansilinear: X2 Income offer curve mP X1
1 X* X1 XBudget lines 2
Price offer curve P1
Demand Curve
X1
I Engel Curve Slope=aP 1X1 P1
Demand curve
X1=
aa?b?mP 1I
Engel curve x1
X1