1. TEORI PERMINTAAN DAN PENAWARAN
Pertemuan 2
TEORI PERMINTAAN DAN PENAWARAN

2. AGENDA
Demand
Supply
Equilibrium

3. DEMAND
Quantity demanded is the amount of a good that buyers are willing and able to purchase.
Law of Demand
The law of demand states that, other things equal, the quantity demanded of a good falls when the price of the good rises. 8

4. The Demand Curve: The Relationship between Price and Quantity Demanded
Demand Schedule
The demand schedule is a table that shows the relationship between the price of the good and the quantity demanded. 17

5. Catherine’s Demand Schedule17

6. The Demand Curve: The Relationship between Price and Quantity Demanded
The demand curve is a graph of the relationship between the price of a good and the quantity demanded. 17

7. Figure 1 Catherine’s Demand Schedule and Demand Curve
Price of
Ice-Cream Cone
$3.00
2.50
1. A decrease
in price
...
2.00
1.50
1.00
0.50 1 2 3 4 5 6 7 8 9 10 11 12
Quantity of 2.
...
increases quantity
of cones demanded.
Ice-Cream Cones
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8. Market Demand versus Individual Demand
Market demand refers to the sum of all individual demands for a particular good or service.
Graphically, individual demand curves are summed horizontally to obtain the market demand curve.

9. Shifts in the Demand Curve
Change in Quantity Demanded
Movement along the demand curve.
Caused by a change in the price of the product. 19

10. Changes in Quantity Demanded
Price of Ice-Cream Cones
A tax that raises the price of ice-cream cones results in a movement along the demand curve. B
$2.00 A
1.00 D 4 8
Quantity of Ice-Cream Cones

11. Shifts in the Demand Curve
Consumer income
Prices of related goods
Tastes
Expectations
Number of buyers 11

12. Shifts in the Demand Curve
Change in Demand
A shift in the demand curve, either to the left or right.
Caused by any change that alters the quantity demanded at every price. 19

13. Figure 3 Shifts in the Demand Curve
Price of
Ice-Cream
Cone
Increase
in demand
Decrease
in demand
Demand
curve, D 2
Demand
curve, D 1
Demand curve, D 3
Quantity of
Ice-Cream Cones

14. Shifts in the Demand Curve
Consumer Income
As income increases the demand for a normal good will increase.
As income increases the demand for an inferior good will decrease.

15. Consumer Income Normal Good
Price of Ice-Cream Cone
$3.00
An increase in income...
2.50
Increase
in demand
2.00
1.50
1.00
0.50 D2 D1
Quantity of Ice-Cream Cones 1 2 3 4 5 6 7 8 9 10 11 12

16. Consumer Income Inferior Good
Price of Ice-Cream Cone
$3.00
2.50
An increase in income...
2.00
Decrease
in demand
1.50
1.00
0.50 D2 D1
Quantity of Ice-Cream Cones 1 2 3 4 5 6 7 8 9 10 11 12

17. Shifts in the Demand Curve
Prices of Related Goods
When a fall in the price of one good reduces the demand for another good, the two goods are called substitutes.
When a fall in the price of one good increases the demand for another good, the two goods are called complements.

18. Table 1 Variables That Influence Buyers

19. SUPPLY
Quantity supplied is the amount of a good that sellers are willing and able to sell.
Law of Supply
The law of supply states that, other things equal, the quantity supplied of a good rises when the price of the good rises. 25

20. The Supply Curve: The Relationship between Price and Quantity Supplied
Supply Schedule
The supply schedule is a table that shows the relationship between the price of the good and the quantity supplied. 29

21. Ben’s Supply Schedule 29

22. The Supply Curve: The Relationship between Price and Quantity Supplied
The supply curve is the graph of the relationship between the price of a good and the quantity supplied. 29

23. Figure 5 Ben’s Supply Schedule and Supply Curve
Price of
Ice-Cream
Cone
$3.00
2.50
1. An
increase
in price
...
2.00
1.50
1.00
0.50 1 2 3 4 5 6 7 8 9 10 11 12
Quantity of
Ice-Cream Cones 2.
...
increases quantity of cones supplied.

24. Market Supply versus Individual Supply
Market supply refers to the sum of all individual supplies for all sellers of a particular good or service.
Graphically, individual supply curves are summed horizontally to obtain the market supply curve.

25. Shifts in the Supply Curve
Input prices
Technology
Expectations
Number of sellers 27

26. Shifts in the Supply Curve
Change in Quantity Supplied
Movement along the supply curve.
Caused by a change in anything that alters the quantity supplied at each price. 30

27. Change in Quantity Supplied
Price of Ice-Cream Cone S C
$3.00
A rise in the price of ice cream cones results in a movement along the supply curve. A
1.00
Quantity of Ice-Cream Cones 1 5 30

28. Shifts in the Supply Curve
Change in Supply
A shift in the supply curve, either to the left or right.
Caused by a change in a determinant other than price. 30

29. Figure 7 Shifts in the Supply Curve
Price of
Supply curve, S 3
Ice-Cream
curve,
Supply S 1
Cone
Supply
curve, S 2
Decrease
in supply
Increase
in supply
Quantity of
Ice-Cream Cones

30. Table 2 Variables That Influence Sellers

31. SUPPLY AND DEMAND TOGETHER
Equilibrium refers to a situation in which the price has reached the level where quantity supplied equals quantity demanded. 36

32. SUPPLY AND DEMAND TOGETHER
Equilibrium Price
The price that balances quantity supplied and quantity demanded.
On a graph, it is the price at which the supply and demand curves intersect.
Equilibrium Quantity
The quantity supplied and the quantity demanded at the equilibrium price.
On a graph it is the quantity at which the supply and demand curves intersect. 36

33. SUPPLY AND DEMAND TOGETHER
Demand Schedule
Supply Schedule
At $2.00, the quantity demanded is equal to the quantity supplied! 36

34. Figure 8 The Equilibrium of Supply and Demand
Price of
Ice-Cream
Cone
Supply
Demand
Equilibrium
Equilibrium price
$2.00
Equilibrium
quantity 1 2 3 4 5 6 7 8 9 10 11 12 13
Quantity of Ice-Cream Cones

35. Figure 9 Markets Not in Equilibrium
(a) Excess Supply
Price of
Ice-Cream
Supply
Cone
Surplus
Demand
$2.50 10 4
2.00 7
Quantity of
Quantity
demanded
Quantity
supplied
Ice-Cream
Cones

36. Equilibrium
Surplus
When price > equilibrium price, then quantity supplied > quantity demanded.
There is excess supply or a surplus.
Suppliers will lower the price to increase sales, thereby moving toward equilibrium.

37. Equilibrium
Shortage
When price < equilibrium price, then quantity demanded > the quantity supplied.
There is excess demand or a shortage.
Suppliers will raise the price due to too many buyers chasing too few goods, thereby moving toward equilibrium.

38. Figure 9 Markets Not in Equilibrium
(b) Excess Demand
Price of
Ice-Cream
Supply
Cone
Demand
$2.00 7
1.50 10 4
Shortage
Quantity of
Quantity
supplied
Quantity
demanded
Ice-Cream
Cones

39. Law of supply and demand
Equilibrium
Law of supply and demand
The claim that the price of any good adjusts to bring the quantity supplied and the quantity demanded for that good into balance.

40. Three Steps to Analyzing Changes in Equilibrium
Decide whether the event shifts the supply or demand curve (or both).
Decide whether the curve(s) shift(s) to the left or to the right.
Use the supply-and-demand diagram to see how the shift affects equilibrium price and quantity. 45

41. Figure 10 How an Increase in Demand Affects the Equilibrium
Price of
Ice-Cream
1. Hot weather increases
the demand for ice cream . . .
Cone D D
Supply
New equilibrium
$2.50 10
resulting
in a higher
price . . .
2.00 7
Initial
equilibrium
Quantity of 3.
. . .
and a higher
quantity sold.
Ice-Cream Cones

42. Three Steps to Analyzing Changes in Equilibrium
Shifts in Curves versus Movements along Curves
A shift in the supply curve is called a change in supply.
A movement along a fixed supply curve is called a change in quantity supplied.
A shift in the demand curve is called a change in demand.
A movement along a fixed demand curve is called a change in quantity demanded.

43. Figure 11 How a Decrease in Supply Affects the Equilibrium
Price of
1. An increase in the
price of sugar reduces
the supply of ice cream. . .
Ice-Cream
Cone S2 S1
Demand
New
equilibrium
$2.50 4
resulting
in a higher
price of ice
cream . . .
Initial equilibrium
2.00 7
Quantity of 3.
. . .
and a lower
quantity sold.
Ice-Cream Cones

44. Table 4 What Happens to Price and Quantity When Supply or Demand Shifts?
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45. Elasticity . . .
… allows us to analyze supply and demand with greater precision.
… is a measure of how much buyers and sellers respond to changes in market conditions

46. THE ELASTICITY OF DEMAND
Price elasticity of demand is a measure of how much the quantity demanded of a good responds to a change in the price of that good.
Price elasticity of demand is the percentage change in quantity demanded given a percent change in the price.

47. The Price Elasticity of Demand and Its Determinants
Availability of Close Substitutes
Necessities versus Luxuries
Definition of the Market
Time Horizon

48. The Price Elasticity of Demand and Its Determinants
Demand tends to be more elastic :
the larger the number of close substitutes.
if the good is a luxury.
the more narrowly defined the market.
the longer the time period.

49. Computing the Price Elasticity of Demand
The price elasticity of demand is computed as the percentage change in the quantity demanded divided by the percentage change in price.

50. Computing the Price Elasticity of Demand
Example: If the price of an ice cream cone increases from $2.00 to $2.20 and the amount you buy falls from 10 to 8 cones, then your elasticity of demand would be calculated as:

51. The Midpoint Method: A Better Way to Calculate Percentage Changes and Elasticities
The midpoint formula is preferable when calculating the price elasticity of demand because it gives the same answer regardless of the direction of the change.

52. The Midpoint Method: A Better Way to Calculate Percentage Changes and Elasticities
Example: If the price of an ice cream cone increases from $2.00 to $2.20 and the amount you buy falls from 10 to 8 cones, then your elasticity of demand, using the midpoint formula, would be calculated as:

53. The Variety of Demand Curves
Inelastic Demand
Quantity demanded does not respond strongly to price changes.
Price elasticity of demand is less than one.
Elastic Demand
Quantity demanded responds strongly to changes in price.
Price elasticity of demand is greater than one.

54. Computing the Price Elasticity of Demand$5 4
Demand 50
100
Quantity
Demand is price elastic

55. The Variety of Demand Curves
Perfectly Inelastic
Quantity demanded does not respond to price changes.
Perfectly Elastic
Quantity demanded changes infinitely with any change in price.
Unit Elastic
Quantity demanded changes by the same percentage as the price.

56. Figure 1 The Price Elasticity of Demand
(a) Perfectly Inelastic Demand: Elasticity Equals 0
Price
Demand
100 $5
1. An
increase
in price . . . 4
Quantity
leaves the quantity demanded unchanged.

57. Figure 1 The Price Elasticity of Demand
(b) Inelastic Demand: Elasticity Is Less Than 1
Price
Demand $5 90
1. A 22%
increase
in price . . . 4
100
Quantity
leads to an 11% decrease in quantity demanded.

58. Figure 1 The Price Elasticity of Demand
(c) Unit Elastic Demand: Elasticity Equals 1
Price
Demand $5 80
1. A 22%
increase
in price . . . 4
100
Quantity
leads to a 22% decrease in quantity demanded.

59. Figure 1 The Price Elasticity of Demand
(d) Elastic Demand: Elasticity Is Greater Than 1
Price
Demand $5 50
1. A 22%
increase
in price . . . 4
100
Quantity
leads to a 67% decrease in quantity demanded.

60. Figure 1 The Price Elasticity of Demand
(e) Perfectly Elastic Demand: Elasticity Equals Infinity
Price
1. At any price
above $4, quantity
demanded is zero. $4
Demand
2. At exactly $4,
consumers will
buy any quantity.
3. At a price below $4,
quantity demanded is infinite.
Quantity

61. Nilai Keterangan Implikasi
> 1 Elastis % perubahan Q > % perubahan P
= 1 Unitary Elastis % perubahan Q = % perubahan P
< 1 Inelastis % perubahan Q < % perubahan P

62. Total Revenue and the Price Elasticity of Demand
Total revenue is the amount paid by buyers and received by sellers of a good.
Computed as the price of the good times the quantity sold.
TR = P x Q

63. Figure 2 Total Revenue Price $4 P × Q = $400 P (revenue) Demand 100
Quantity Q

64. Elasticity and Total Revenue along a Linear Demand Curve
With an inelastic demand curve, an increase in price leads to a decrease in quantity that is proportionately smaller. Thus, total revenue increases.

65. Figure 3 How Total Revenue Changes When Price Changes: Inelastic Demand
An Increase in price from $1
to $3 …
… leads to an Increase in total revenue from $100 to $240
Demand
Demand $3 80
Revenue = $240 $1
100
Revenue = $100
Quantity
Quantity

66. Elasticity and Total Revenue along a Linear Demand Curve
With an elastic demand curve, an increase in the price leads to a decrease in quantity demanded that is proportionately larger. Thus, total revenue decreases.

67. Figure 4 How Total Revenue Changes When Price Changes: Elastic Demand
An Increase in price from $4
to $5 …
… leads to an decrease in total revenue from $200 to $100 $5 20
Demand
Demand
Revenue = $100 $4 50
Revenue = $200
Quantity
Quantity

68. Elasticity of a Linear Demand Curve

69. Income Elasticity of Demand
Income elasticity of demand measures how much the quantity demanded of a good responds to a change in consumers’ income.
It is computed as the percentage change in the quantity demanded divided by the percentage change in income.

70. Computing Income Elasticity

71. Income Elasticity Types of Goods
Normal Goods
Inferior Goods
Higher income raises the quantity demanded for normal goods but lowers the quantity demanded for inferior goods.

72. Goods consumers regard as necessities tend to be income inelastic
Income Elasticity
Goods consumers regard as necessities tend to be income inelastic
Examples include food, fuel, clothing, utilities, and medical services.
Goods consumers regard as luxuries tend to be income elastic.
Examples include sports cars, furs, and expensive foods.

73. implikasi Nilai Golongan Barang interprestasi Positif Income-Normal
barang normal, kenaikan pendapatan akan berpengaruh dengan kenaikan jumlah barang yang diminta.
 Nol
Income-Independen
barang netral, kenaikan / penurunan
pendapatan tidak berpengaruh terhadap jumlah konsumsi
 Negatif
Income-Inferior
konsumsi akan berkurang bila pendapatan konsumen naik

74. CROSS ELASTICITY
Cross elasticity of demand measures how much the quantity demanded of a good responds to a change in the other price.
It is computed as the percentage change in the quantity demanded divided by the percentage change in the other price

75. Computing Cross Elasticity
CROSS ELASTICITY = % Change in Quantity Demanded Y
% Change in The Other Price (X) 75

76. IMPLIKASI NILAI JENIS BARANG IMPLIKASI Positif Subtitusi
Barang-barang bisa saling mengganti satu sama lain
Nol
Independen
Barang-barang tersebut tidak berhubungan dalam pengkonsumsiannya
Negatif
Komplementer
Barang-barang tersebut dikonsumsi secara bersama-sama

77. THE ELASTICITY OF SUPPLY
Price elasticity of supply is a measure of how much the quantity supplied of a good responds to a change in the price of that good.
Price elasticity of supply is the percentage change in quantity supplied resulting from a percent change in price.

78. Figure 6 The Price Elasticity of Supply
(a) Perfectly Inelastic Supply: Elasticity Equals 0
Price
Supply $5
1. An
increase
in price . . . 4
100
Quantity
leaves the quantity supplied unchanged.

79. Figure 6 The Price Elasticity of Supply
(b) Inelastic Supply: Elasticity Is Less Than 1
Price
Supply
110 $5
1. A 22%
increase
in price . . .
100 4
Quantity
leads to a 10% increase in quantity supplied.

80. Figure 6 The Price Elasticity of Supply
(c) Unit Elastic Supply: Elasticity Equals 1
Price
Supply
125 $5
1. A 22%
increase
in price . . .
100 4
Quantity
leads to a 22% increase in quantity supplied.

81. Figure 6 The Price Elasticity of Supply
(d) Elastic Supply: Elasticity Is Greater Than 1
Price
Supply $5
200
1. A 22%
increase
in price . . . 4
100
Quantity
leads to a 67% increase in quantity supplied.

82. Figure 6 The Price Elasticity of Supply
(e) Perfectly Elastic Supply: Elasticity Equals Infinity
Price
1. At any price
above $4, quantity
supplied is infinite. $4
Supply
2. At exactly $4,
producers will
supply any quantity.
3. At a price below $4,
quantity supplied is zero.
Quantity

83. Determinants of Elasticity of Supply
Ability of sellers to change the amount of the good they produce.
Beach-front land is inelastic.
Books, cars, or manufactured goods are elastic.
Time period.
Supply is more elastic in the long run.

84. Computing the Price Elasticity of Supply
The price elasticity of supply is computed as the percentage change in the quantity supplied divided by the percentage change in price.

85. THE APPLICATION OF SUPPLY, DEMAND, AND ELASTICITY
Examine whether the supply or demand curve shifts.
Determine the direction of the shift of the curve.
Use the supply-and-demand diagram to see how the market equilibrium changes.

86. Figure 8 An Increase in Supply in the Market for Wheat
Price of
Wheat
1. When demand is inelastic,
an increase in supply
. . .
leads
to a large fall
in price . . . S1 S2
Demand $3
100 2
110
Quantity of
and a proportionately smaller
increase in quantity sold. As a result,
revenue falls from $300 to $220.
Wheat

87. Elasticity and Tax Incidence
Tax incidence is the manner in which the burden of a tax is shared among participants in a market. 21 87 31

88. Elasticity and Tax Incidence
Tax incidence is the study of who bears the burden of a tax.
Taxes result in a change in market equilibrium.
Buyers pay more and sellers receive less, regardless of whom the tax is levied on. 21 88 31

89. Figure 6 A Tax on Buyers Price of Ice-Cream Price buyers pay Supply,
Cone D1 D2
$3.30 90
Equilibrium without tax
Tax ($0.50)
Price
without
tax
3.00
100
A tax on buyers
shifts the demand
curve downward
by the size of
the tax ($0.50).
2.80
Equilibrium
with tax
Price
sellers
receive
Quantity of
Ice-Cream Cones

90. Elasticity and Tax Incidence
What was the impact of tax?
Taxes discourage market activity.
When a good is taxed, the quantity sold is smaller.
Buyers and sellers share the tax burden. 22 90 30

91. Figure 7 A Tax on Sellers Price of Ice-Cream Demand, D1
shifts the supply
curve upward
by the amount of
the tax ($0.50).
Price
buyers
pay
Cone S2
Equilibrium
with tax S1
$3.30 90
Tax ($0.50)
Price
without
tax
3.00
100
Equilibrium without tax
2.80
Price
sellers
receive
Quantity of
Ice-Cream Cones

92. Perbedaan Konsep
Menurut Ibnu Taimiyyah, permintaan suatu barang adalah  hasrat terhadap sesuatu.
Konsep permintaan merupakan hubungan antara jumlah barang yang diminta dengan berbagai tingkat harga.

93. Hukum Permintaan
pada masa zaman sebelum kenabian atau sesudah masa kenabian, sudah ada pemikiran yang menjadi kesepakatan bersama bahwa tinggi rendahnya pemintaan terhadap barang ditentukan oleh harga barang yang bersangkutan.
Abu Yusuf mengatakan
“Kadang-kadang makanan melimpah, tetapi tetap mahal dan kadang-kadang makanan sangat sedikit tetapi murah”

94. Landasan Filosofi
Islam dalam hal ini khususnya perekonomian sangat menjunjung nilai kesederhanaan.
norma-norma Islam yang selalu menemani kehidupan manusia yaitu halal dan haram.

95. Ibnu Taimiyyah (1263-1328 M) dalam kitab Majmu’ Fatawa
hal-hal yang mempengaruhi terhadap permintaan suatu barang:
Keinginan atau selera masyarakat
Jumlah para peminat (Tullab)
Kualitas pembeli (Al-Mu’awid)
Lemah atau kuatnya kebutuhan terhadap suatu barang.
Besarnya biaya transaksi.

96. Faktor-faktor Penawaran dalam Islam
Mashlahah
Keuntungan

97. Perbedaan Teori Permintaan Konvensional dengan Permintaan Islami
Men Islami :
Permintaan Islam bukan hanya berasal dari data pengalaman tapi juga berasal dari firman-firman Allah.
Konsep permintaan dalam Islam menilai suatu komoditi tidak semuanya bisa untuk dikonsumsi maupun digunakan.
Dalam motif permintaan Islam menekankan pada tingkat kebutuhan konsumen terhadap barang

98. Men Konvensional :
ekonomi konvensional filosofi dasarnya terfokus pada tujuan keuntungan dan material.
dalam permintaan konvensional, semua komoditi dinilai sama, bisa dikonsumsi atau digunakan.
motif permintaan konvensional lebih didominasi oleh nilai-nilai kepuasani.