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Short-run outcomes for perfectly competitive firms

The average cost and average variable cost curves divide the marginal cost curve into three segments, as shown in [link] . At the market price, which the perfectly competitive firm accepts as given, the profit-maximizing firm chooses the output level where price or marginal revenue, which are the same thing for a perfectly competitive firm, is equal to marginal cost: P = MR = MC.

Profit, loss, shutdown

The graph shows how the marginal cost curve reveals three different zones: above the zero-profit point, between the zero profit point and the shutdown point, and below the shutdown point.
The marginal cost curve can be divided into three zones, based on where it is crossed by the average cost and average variable cost curves. The point where MC crosses AC is called the zero-profit point. If the firm is operating at a level of output where the market price is at a level higher than the zero-profit point, then price will be greater than average cost and the firm is earning profits. If the price is exactly at the zero-profit point, then the firm is making zero profits. If price falls in the zone between the shutdown point and the zero-profit point, then the firm is making losses but will continue to operate in the short run, since it is covering its variable costs. However, if price falls below the price at the shutdown point, then the firm will shut down immediately, since it is not even covering its variable costs.

First consider the upper zone, where prices are above the level where marginal cost (MC) crosses average cost (AC) at the zero profit point. At any price above that level, the firm will earn profits in the short run. If the price falls exactly on the zero profit point where the MC and AC curves cross, then the firm earns zero profits. If a price falls into the zone between the zero profit point, where MC crosses AC, and the shutdown point, where MC crosses AVC, the firm will be making losses in the short run—but since the firm is more than covering its variable costs, the losses are smaller than if the firm shut down immediately. Finally, consider a price at or below the shutdown point where MC crosses AVC. At any price like this one, the firm will shut down immediately, because it cannot even cover its variable costs.

Marginal cost and the firm’s supply curve

For a perfectly competitive firm, the marginal cost curve is identical to the firm’s supply curve starting from the minimum point on the average variable cost curve. To understand why this perhaps surprising insight holds true, first think about what the supply curve means. A firm checks the market price and then looks at its supply curve to decide what quantity to produce. Now, think about what it means to say that a firm will maximize its profits by producing at the quantity where P = MC. This rule means that the firm checks the market price, and then looks at its marginal cost to determine the quantity to produce—and makes sure that the price is greater than the minimum average variable cost. In other words, the marginal cost curve above the minimum point on the average variable cost curve becomes the firm’s supply curve.

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Questions & Answers

the relationship between two concept supply and Demand
Lebogang Reply
what is globalization
Nuertey Reply
what is the best definition of economic?
Humble Reply
what is aggregat demand in open economy
Dagim Reply
Aggregate demand is expressed as the total amount of money exchanged for those goods and services at a specific price level and point in time.
What is the full meaning of GDP
Akinbulejo Reply
gross domestic product
Gross Domestic Product
Formula for calculating the percentage of change in price, quantity, price elasticity of demand
Augustina Reply
Given that the elasticity of supply for a good is 2 and the percentage change in price is 45%.What is the percentage change in quantity supplied
Mbe Reply
Please don't understand
percentage change should be 44%
state and explainfour function of a costumer service
Egba Reply
the circular flow model of the economy is a simplification showing how the economy works and the relationship between income,production and spending in the economy as a whole
Anna Reply
It is an idea that show us the way the economy works about their income, production, and spending in the economy
what is circular flow
Ntokozo Reply
what is economics?
Dorcas Reply
Economics is defined as the science that study human behaviour as a relationship between ends and scarce means which have alternative uses.
economics is a social science concerned with the production,distribution, and consumption of goods and services
Economics as a science studies human behaviour as a relationship between ends and scarce means with alternative use.
economics can be defined as social science which studies human behavior as a relationship between ends and scare means which have alternative uses.... Lionel C Robins
in 2021 Amazon reduced the annual subscription fee for its prime membership service which provides free two_day shipping on many goods and other benefits, from $119 to $99. Zoppa consulting, an investment firm estimated that before the price reduction, prime had 62million subscribers globally. If so, what is the arc elasticity of demand for a prime membership.
Joan Reply
Differences between microeconomics and macroeconomics
tatiana Reply
Macroeconomics deal with the economy as a whole.that is an economy affect the firm ,government and the households eg.unemployment, whilst Microeconomics deal with the the decision making of households,firm and government separately.
Microeconomics is the branch of economic which studies the behaviour of individual households, firms and industries whiles macroeconomic studies the economy as a whole. It looks at the economy from a a broader perspective.
what is Economics
Ebem Reply
the branch of knowledge concerned with the production, consumption, and transfer of wealth and has Influence by sociology!!!!
Economics is the study of how humans make decisions when they want to fulfil their requirements and desires for goods, services and resources.
Economics is the study how humans make decisions in the faces of scarcity.
economic is the study of how human make decision in the fact of scarcity.
Economics is a social science which study human behavior as a relationship between earn and scarce mean which have alternative uses
what is market structure
market structure in economics depicts how firms are differentiated and categorised based on types of goods they sell and how their operations are affected by external factors and elements.
what is economic theory
what is demand
Gooluck Reply
demand is the willingness to purchase something
demand is the potential ability or williness to purchases something at a particular price at a given period of time..
Demand refers to as quantities of a goods and services in which consumers are willing and able to purchase at a given period of time. Demand can also be defined as the desire backed by ability to purchase .

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Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
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