Economics involves many graphs and curves, and this is because economists like to break down concepts so that they are easily understood by everybody else. The demand curve is one such concept. As a consumer, you contribute to an important concept in economics, which is the concept of demand. The demand curve helps to explain your behavior as a consumer and how you and other consumers in the market behave. How does the demand curve do this? Read on, and let's find out together!
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Jetzt kostenlos anmeldenEconomics involves many graphs and curves, and this is because economists like to break down concepts so that they are easily understood by everybody else. The demand curve is one such concept. As a consumer, you contribute to an important concept in economics, which is the concept of demand. The demand curve helps to explain your behavior as a consumer and how you and other consumers in the market behave. How does the demand curve do this? Read on, and let's find out together!
What is the definition of the demand curve in economics? The demand curve is a graphical illustration of the relationship between price and quantity demanded. But let's not get ahead of ourselves. What is demand? Demand is the willingness and ability of consumers to purchase a given good at any given time. It is this willingness and ability that makes one a consumer.
The demand curve is a graphical illustration of the relationship between price and quantity demanded.
Demand is the willingness and ability of consumers to purchase a given good at a given price at a given time.
Whenever you see the concept of demand in action, quantity demanded and price come into play. This is because, given that we do not have unlimited money, we can only purchase a limited quantity of goods at any given price. So, what are the concepts of price and quantity demanded? Price refers to the amount of money that consumers have to pay to acquire a given good at any given time. Quantity demanded, on the other hand, is the total amount of a given good consumers demand at different prices.
Price refers to the amount of money that consumers have to pay to acquire a given good at a given time.
Quantity demanded refers to the total amount of a given good consumers demand at different prices.
The demand curve shows the price of a good relative to its quantity demanded. We plot the price on the vertical axis, and the quantity demanded goes on the horizontal axis. A simple demand curve is presented in Figure 1 below.
The demand curve slopes downward because the demand curve is an illustration of the law of demand.
The law of demand contends that all other things remaining equal, the quantity demanded of a good increases as the price of that good decreases.
The law of demand states that all other things remaining equal, the quantity demanded of a good increases as the price of that good decreases.
It can also be said that price and quantity demanded are inversely related.
The demand curve in perfect competition is flat or a straight horizontal line parallel to the horizontal axis.
Why is this so?
This is because in perfect competition, as buyers have perfect information, they know who is selling the same product for a lower price. As a result, if one seller is selling the product for too high a price, the consumers will simply not buy from that seller. Rather, they will buy from a seller who sells the same product for cheaper. Therefore, all firms must sell their product at the same price in perfect competition, which leads to a horizontal demand curve.
Since the product is being sold at the same price, the consumers buy as much as they can afford to buy or until the firm runs out of product. Figure 2 below shows the demand curve in perfect competition.
Some factors can cause a shift in the demand curve. These factors are referred to by economists as the determinants of demand. The determinants of demand are factors that cause a shift in the demand curve of a good.
There is a rightward shift in the demand curve when demand increases. Conversely, there is a leftward shift in the demand curve when demand decreases at every price level.
Figure 3 illustrates an increase in demand, whereas Figure 4 illustrates a decrease in demand.
Determinants of demand are factors that cause a shift in the demand curve of a good.
Figure 3 above depicts a demand curve shift to the right from D1 to D2 due to an increase in demand.
As sketched in Figure 4 above, the demand curve shifts to the left from D1 to D2 due to a decrease in demand.
The main determinants of demand are income, the price of related goods, tastes, expectations, and the number of buyers. Let's explain these briefly.
Read our article on Change in Demand to learn more!
There are two main types of demand curves. These include the individual demand curve and the market demand curve. As the names suggest, the individual demand curve represents demand for a single consumer, whereas the market demand curve represents demand for all the consumers in the market.
The individual demand curve represents the relationship between the price and quantity demanded for a single consumer.
The market demand curve represents the relationship between the price and quantity demanded for all consumers in the market.
Market demand is a summation of all individual demand curves. This is illustrated in Figure 5 below.
As illustrated in Figure 5, D1 represents the individual demand curves, whereas D2 represents the market demand curve. The two individual curves are summed up to make the market demand curve.
Now, let's look at an example of the demand curve by showing the effect of multiple buyers on demand.
The demand schedule presented in Table 1 shows individual demand for one consumer and market demand for two consumers for towels.
Price ($) | Towels (1 consumer) | Towels (2 consumers) |
5 | 0 | 0 |
4 | 1 | 2 |
3 | 2 | 4 |
2 | 3 | 6 |
1 | 4 | 8 |
Table 1. Demand Schedule for Towels
Show the individual demand curve and the market demand curve on the same graph. Explain your answer.
Solution:
We plot the demand curves with the price on the vertical axis, and the quantity demanded on the horizontal axis.
Doing this, we have:
As shown in Figure 6, the market demand curve combines two individual demand curves.
The inverse demand curve shows the price as a function of the quantity demanded.
Normally, the demand curve shows how the quantity demanded changes as a result of changes in price. However, in the case of the inverse demand curve, price changes as a result of changes in quantity demanded.
Let's express the two mathematically:
For demand:
\(Q=f(P)\)
For inverse demand:
\(P=f^{-1}(Q)\)
To find the inverse demand function, we simply need to make P the subject of the demand function. Let's take a look at an example below!
For instance, if the demand function is:
\(Q=100-2P\)
The inverse demand function becomes:
\(P=50-\frac{1}{2} Q\)
The inverse demand curve and the demand curve are essentially the same, hence are illustrated in the same way.
Figure 7 shows the inverse demand curve.
The inverse demand curve presents price as a function of quantity demanded.
The demand curve in economics is defined as a graphical illustration of the relationship between price and quantity demanded.
The demand curve demonstrates the quantity of a product consumers will buy at different prices.
The demand curve is important because it illustrates the behavior of consumers in the market.
This is because in perfect competition, as buyers have perfect information, they know who is selling the same product for a lower price. As a result, if one seller is selling the product for too high a price, the consumers will simply not buy from that seller. Rather, they will buy from a seller who sells the same product for cheaper. Therefore, all firms must sell their product at the same price in perfect competition, which leads to a horizontal demand curve.
The demand curve shows the relationship between quantity demanded and price and is downward sloping. The supply curve shows the relationship between quantity supplied and price and is upward sloping.
Define the demand curve.
The demand curve in economics is defined as a graphical illustration of the relationship between price and quantity demanded.
What is demand?
Demand is the willingness and ability of consumers to purchase a given good at a given price at a given time.
Define price.
Price refers to the amount of money consumers have to pay to acquire a given good at a given time.
Define quantity demanded.
Quantity demanded refers to the total amount of a given good consumers demand at different prices.
What is the law of demand?
The law of demand states that all other things remaining equal, the quantity demanded of a good increases as the price of that good decreases.
Market demand tends to be higher than individual demand. Why?
Because the number of consumers increases in market demand.
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