3 II 3 II

(Demand) (Supply)

(Supply)

(Rationing)

/: (Law of Demand)

/: (Law of Supply)

(Market equilibrium) (Market equilibrium)

(Shock)

/

/

/ / (Elasticity)

(Price Elasticity of Demand)

(Price

(Price Elasticity)

10 11 ( 5 ))

?

(Price Elasticity of Demand)

(Price

(Price Elasticity)

(%Q) (% (% P) x%

%

(%P)

mp3 50 60

% 100

(Price 100

50 60-

(Price Elasticity)

50 = 10 100

(100x10)/50 20% %P = +20

(%P)

P0 P1 P P P

(Price P1 P0 P

100 P x 100 / P0

(Price Elasticity)

P x 100 / P0 % %P = P x 100 / P0

(%Q) (%Q)

mp3 50 20 60

20 60 15

(Price %

100

(Price Elasticity)

20 15-20 = -5 100 (100x (-5))

/20 25%/20 25% %Q = -25

* *:

(%Q)

Q0

Q1 Q0 Q1 Q0

(Price 0 1 0

Q 100 Q x

(Price Elasticity)

100 Q x 100 / Q0

Q x 100 / Q0 % %Q = Q x 100 / Q0

(Price Elasticity of Demand) of Demand)

(%Q) (% P)

(Price (Price Elasticity)

%Q = Q x 100 / Q0 %P P x 100 / P %P = P x 100 / P0

(Ed)

mp3 50 20

60 15

(Price 15

mp3 ?(Price Elasticity)

(Price Elasticity of Demand)

(Price El i1 (Price Elasticity) Inelastic

Elastic

1

1

ElasticUnitary1

: /

Ed Ed

(Price

Ed Ed - 0.06 - 0.29(Price

Elasticity) (- 0.13

()- 0.60

) - 0.15 - 1.31 0.15 1.31 - 0.21

- 1.52

(Price Elasticity of Demand)

(Price

Price

(Price Elasticity) AP1P1

P2 CB

DB

Quantity

D*

QuantityQ1 Q2 Q3

(Price Elasticity of Demand)

(Price (Price Elasticity)

ElasticPerfectlyInelasticPerfectly0

?

( ) P

(Price () P

(Price Elasticity)

vs.

: /

? ()

(Price

(Price Elasticity)

(Price elasticity of supply)

(Price

(%Q) (% P)

(Price Elasticity)

(% P)

(Price elasticity of supply)

(Price El i1 (Price Elasticity) Inelastic

Elastic

1

1

ElasticUnitary1

. 20 7 500

7,500 . . 10

(Price 4,500 .

?

(Price Elasticity)

(Price elasticity of

supply)

S* (Price

Price

SB(Price Elasticity)

BC

PP2

AP1

QuantityQuantity

(Price elasticity of supply)

Price Price S

SP* SP

Quantity

E = QuantityQ*

E 0EP = EP = 0

?

( k )

( Sunk Cost) Es 0

(Price

(E )

(Price Elasticity)

(Es )

(E ) (Es )

( t ) (new entry)

: / ( ) ? ()

- /

-

(Price

- -

(Price Elasticity)

-

?

Supply shift

(Price Price S*(Price Elasticity)

SP1 E*

P E

Demand

Quantity0 Q* Q

?

Supply shift

(Price Price S*(Price Elasticity)

S

S

SP1 E*

D d

PE

Demand

Quantity0Q* Q

(Price

(Price Elasticity)

(Cross-Price xy = %Qx = Qx/Qx

%Py Py/PyPrice Elasticity)

xy (+) (-)

(Income

( co eElasticity of demand)

- (Income: I) (Qd)

(Income ?

(Income Elasticity)

(%Qd) (% I)

EI = %Qd% I

(Income

( co eElasticity of demand)

- EI > 0 (+) (Normal Goods)

(Income (Normal Goods)- 0 < |Ei | < 1

(Income Elasticity)

(Necessary Goods) - | Ei | > 1 (Luxurious Goods) ( )

(Income

( co eElasticity of demand)

- Ei < 0 (-) (Inferior Goods)

(Income ( ) / 2

(Income Elasticity)

/ 2

(Income

( co eElasticity of demand): /

(Income Ei Ei

(Income Elasticity)

- 1.52 1.03 - 0.31 1.32

0.25 2.25 0.73

4.51