DEMAND DAN SUPPLYPENGANTAR ILMU EKONOMI

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• Demand• Wants,Needs And Demand• Faktor-Faktor Yang Mempengaruhi

Demand• Supply• Faktor-Faktor Yang Mempengaruhi

supply

DEMAND FUNCTION

To demand something, you must:• Want it• Be able to afford it• Have a definite plan to buy it (Wonderling, 2005)

DEMAND FUNCTION

Wants are the unlimited desires or wishes that people have for goods and services.

How many times have you thought that you would like something ‘if only you could afford it’ or ‘if it weren’t so expensive’?

When we make choices, scarcity guarantees that many – perhaps most – of our wants will never be satisfied.

Demand reflects our plans about which wants to satisfy.

DEMAND FUNCTIONNeed Wants DemandDemand adalah hubungan antara

harga barang dan jumlah permintaan barang

DEMAND FUNCTION

Permintaan adalah keinginan yang disertai kemampuan untuk membeli barang dan jasa pada tingkat harga dan waktu tertentu.

The term ‘demand’ is used to describe the amount of money purchasers are prepared to pay for a commodity.

DEMAND FUNCTION

Hal Penting dalam Permintaan: 1. Kuantitas yang diminta merupakan

kuantitas yang diinginkan2. Keinginan konsumen disertai oleh

kemampuan serta kesediaan untuk membeli (Permintaan efektif)

3. Kuantitas yang diminta dinyatakan dalam satuan waktu

THE LAW OF DEMAND

The law of demand states: Other things remaining the same (Ceteris Paribus), the higher the price of a good, the smaller is the quantity demanded.

KURVA DEMAND

Price

Quantity

DEMAND CURVE AND DEMAND SCHEDULE

Before going any further, you need to understand a critical distinction between demand and quantity demanded.

The term demand refers to the entire relationship between the quantity demanded and the price of a good, illustrated by the demand curve and the demand schedule.

The term quantity demanded refers to the exact quantity demanded at a particular price, or a particular point on a demand curve.

DEMAND CURVE AND DEMAND SCHEDULE Demand Schedule :

A table that shows the relationship between the price of a good and the quantity demanded

Demand Curve :A graph of the relationship between the price of a good and the quantity demanded

A CHANGE IN DEMANDWhen any factor that influences buying

plans, other than the price of the good, there is a change in demand.

Figure 2 illustrates one such change – an increase in demand. When demand increases, the demand curve shifts to the right and the quantity demanded is greater at each prices.

FIGURE 2: AN INCREASE IN DEMAND

Pri

ce (

£ p

er t

ape)

Quantity (millions of tapes /week)1 2 3 4 5 6

New demand schedule (Walkman £30)

Price (£/tape)

Quantity (millions of tapes/week)

A’ 1 7.8

B’ 2 5.9

C’ 3 4.7

D’ 4 4.2

E’ 5 3.81

2

3

4

5

A

B

C

D

E

A’

B’

C’

D’

E’

Demand for tapes (Walkman £125)

Demand for tapes (Walkman £30)

7 8

A CHANGE IN DEMAND

FACTORS INFLUENCING DEMAND

1 Prices of related goods The quantity of any goods and services that

consumers plan to buy depends in part on the price of related goods and services. There are two types: substitutes and complements.

2 Income Other things remaining the same, when

income increases, consumers buy more of most goods, and when income decreases, they buy less of most goods .

Goods for which demand increases as income increases are called normal goods.

Goods for which demand decreases when income increases are called inferior goods.

3 Expected future prices If the price of a good is expected to rise in

the future, and if the good can be stored, the opportunity cost of obtaining the good for future use is lower now than it will be when the price has increased.

So people substitute over time. They buy more of the good before the expected price rise and the demand for the good increases

4 Population Demand also depends on the size and the

age structure of the population. Other things remaining the same, the larger

the population, the greater is the demand for all goods and services, and the smaller the population, the smaller is the demand for all goods and services.

5 Preferences Preferences are an individual’s attitudes

towards and tastes for goods and services . Preferences are shaped by past experience,

genetic factors, advertising information, religious beliefs, and other cultural and social factors.

Changes in the factors that influence buyers’ plans cause either:

1. a movement along the demand curve, or

2. a shift of the demand curve

1. MOVEMENT ALONG THE DEMAND CURVE

If the price of a good changes but everything else remains the same, there is a movement along the demand curve.

For example, if the price of a tape changes from £ 3 to £ 5, the result is a movement along the demand curve, from point C to point E in figure 1.

The negative slope of the demand curve reveals that a decrease in the price of a good or service increases the quantity demanded – the law of demand

2. A SHIFT OF THE DEMAND CURVE If the price of a good remains constant but some other

influence on buyers’ plans changes, there is a change in demand for that good

Figure 2 illustrates such a shift

SUPPLY

Jumlah barang dan jasa yang bersedia dan dapat ditawarkan oleh Produsen kepada konsumen pada setiap tingkat harga selama periode tertentu

Quantity supplied : the amount of a good that sellers are willing and able to sell

HUKUM SUPPLY

Law of supply :“the claim that, other things equal, the

quantity supplied of a good rises when the price of the good rises”

A CHANGE IN SUPPLY

FAKTOR2 YANG MEMPENGARUHI PERUBAHAN SUPPLY

1. Price the quantity supplied rises as the price rises

and falls as the price falls, So we say that the quantity supplied is

positively related to the price of the good

2. Input Price To produce its output of ice cream, Student

Sweets uses various inputs: cream, sugar, flavoring, ice-cream machines, the buildings in which the ice cream is made, and the labor of workers to mix the ingredients and operate the machines.

When the price of one or more of these inputs rises, producing ice cream is less profitable, and your firm supplies less ice cream.

If input prices rise substantially, you might shut down your firm and supply no ice cream at all.

3. Technology The technology for turning the inputs into ice

cream is yet another determinant of supply. The invention of the mechanized ice-cream machine, for example, reduced the amount of labor necessary to make ice cream.

By reducing firms’ costs, the advance in technology raised the supply of ice cream

4. Expectations The amount of ice cream you supply today

may depend on your expectations of the future.

For example, if you expect the price of ice cream to rise in the future, you will put some of your current production into storage and supply less to the market today.

SUPPLY SCHEDULE

Supply Schedule : a table that shows the relationshipbetween the price of a good and the quantity supplied

SUPPLY SCHEDULE

MARKET SUPPLY

The market supply is the sum of the two individual or more supplies.

Market supply depends on all those factors that influence the supply of individual sellers, such as the prices of inputs used to produce the good, the available technology, and expectations.

In addition, the supply in a market depends on the number of sellers

GAMBAR 1: KURVA SUPPLY

Pri

ce

($)

Quantity

P2

P1

Q1 Q2

S

0

KESETIMBANGAN PASAR (MARKET EQUILIBRIUM)

Definisi

Situasi dimana harga terbentuk pada:

Jml demand thd barang = Jml barang yg

disupply

GAMBAR 2: PASAR BARANG …..

Quantity

Q10

Market Equilibri

um

P1Pri

ce

($)

S

D

TUGAS KELOMPOK1. Jelaskan apa yang dimaksud dengan Excess

Demand dan Excess Supply beserta contoh ?

2. Jelaskan hal-hal yang menyebabkan Excess Demand dan Excess Supply terjadi ?

3. Jelaskan penggolongan pembeli dan penjual di pasar ?

4. Jelaskan peranan pemerintah dalam pembentukkan harga pasar?

Thank You….