elasticidade-preço da procura

8/9/2019 Elasticidade-preo Da Procura

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Elasticity . . .

is a measure of how much buyers and

sellers respond to changes in marketconditions

allows us to analyze supply anddemand with greater precision.

Journal Question-Name 3 necessities and3 luxuries that you would buy.


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Computing the Price Elasticity

of Demand$he price elasticity of demand is computedas the percentage change in the !uantitydemanded di"ided by the percentagechange in price.

rice %lasticity & ercentage 'hange in Qd(f )emand ercentage 'hange in rice


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Elasticity, Percentage Changeand Slope

*ecause the price elasticity ofdemand measures how much

!uantity demanded responds tothe price+ it is closely related tothe slope of the demand cur"e.

*ut instead of looking at unitchange+ elasticity looks at

percentage change. ,hat do wemean by percentage change


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Brief Assessment on

Percentages#f there are / tomatoes in a store and youpicked 01 of them+ what percentage of the total

did you pickaul used to weigh 2// lbs last year+ but now he

only weighs 0 lbs. 4ow many lbs did he lose,hat is the percent change of the loss

,hat is the a"erage of 3// and 33/ ,hat isthe midpoint


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of Demand

priceinchange Percentagedemanded quatityinchange Percentage

demand of elasticity Price =

%xample5 #f the price of an ice cream cone increasesfrom 62.// to 62.2/ and the amount you buy falls from0/ to 7 cones then your elasticity of demand would becalculated as5

2 percent10 percent20

100

002

002202

10010

810==

.

)..(

)(


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Computing the Price Elasticity ofDemand Using the idpoint

!ormula

$he midpoint formula is preferable when

calculating the price elasticity of demandbecause it gi"es the same answer regardlessof the direction of the change.

)/ 2]P)/ [(PP(P)/ 2]Q)/ [(QQ(Q

=Demandof ElasticityPrice1212

1212

+

+


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of Demand

%xample5 #f the price of an ice cream cone increasesfrom 62.// to 62.2/ and the amount you buy falls from0/ to 7 cones the your elasticity of demand+ using themidpoint formula+ would be calculated as5

32.25.9

22

2/)20.200.2(

)00.220.2(2/)810(

)810(==

+

+

percent

percent

)/ 2]P)/ [(PP(P)/ 2]Q)/ [(QQ(Q

=Demandof ElasticityPrice1212

1212

+

+


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Perfectly Inelastic Demand

# Elasticity e$uals %

Quantity

Price

4

$5

Demand

1002. ...leaves the quantity demanded unchanged.

1. Anincreasein price...


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Inelastic Demand

# Elasticity is less than &

Quantity

Price

4

$51. A 25%increasein price...

Demand

10002. ...leads t! a 10% decrease in quantity.


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Unit Elastic Demand# Elasticity e$uals &

Quantity

Price

4


Demand

100"52. ...leads t! a 25% decrease in quantity.


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Elastic Demand# Elasticity is greater than &

Quantity

Price

4


Demand

100502. ...leads t! a 50% decrease in quantity.


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Perfectly Elastic Demand# Elasticity e$uals infinity

Quantity

Price

Demand$4

1. At any pricea#!ve $4 quantity

demanded is er!.

2. At e&actly $4c!nsumers 'ill#uy any quantity.

(. At a price #el!' $4

quantity demanded is in)inite.


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Determinants of

Price Elasticity of Demand

Necessities versus Luxuries

Availability of Close ubstitutes

Definition of the !ar"et

#ime $ori%on


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Determinants of Price

Elasticity of Demand)emand tends to be more inelastic

#f the good is a necessity.

#f the time period is shorter.$he smaller the number of close substitutes.

$he more broadly defined the market.


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Determinants of

Price Elasticity of Demand Demand tends to be more elastic &

if the good is a luxury.

the longer the time period.

the larger the number of closesubstitutes.

the more narrowly defined the market.


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Elasticity and 'otal "e(enue

$otal re"enue is the amount paid bybuyers and recei"ed by sellers of a good.

'omputed as the price of the good timesthe !uantity sold.

TR = P x Q


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$4

Demand

Quantity

P

0

Price

P x Q = $400 *t!tal revenue+

100Q

Elasticity and 'otal "e(enue


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'he 'otal "e(enue 'est for

Elasticity

#N%89:$#')%;9N)

%89:$#')%;9N)

)ecrease inrice

%89:$#')%;9N)

#N%89:$#')%;9N)

#ncrease inrice

)ecrease in$otal


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An E)ample of an Inelastic

*ood(il and (il rices$his "ideo will show

the supply side issueswith getting oil out ofthe ground.$hen the "ideo willfocus on the demand=us>? issues of usingoil.

#nsert %conomics @ideoAile 0 and play 9rab (il

clip.


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Income Elasticity of Demand

#ncome elasticity of demand measureshow much the !uantity demanded of a

good responds to a change in consumersBincome.

#t is computed as the percentage change

in the !uantity demanded di"ided by thepercentage change in income.


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Computing Income Elasticity

IncomeElasticity

of Demand

Percentage Changein Q antity

DemandedPercentage Change in Income

=


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Income Elasticity

# 'ypes of *oods # Normal 'oods

#ncome %lasticity is positi"e.

Inferior 'oods#ncome %lasticity is negati"e.

4igher income raises the !uantity demandedfor normal goods but lo(ers the !uantity

demanded for inferior goods )


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Cross Price Elasticity of

Demand%lasticity measure that looks at theimpact a change in the price of one good

has on the demand of another good.C change in demand Q0DC change inprice of Q2.

ositi"e-:ubstitutesNegati"e-'omplements.

elasticidade-preço da procura

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