# Perfect competition firm's output decisions

##### Intros
###### Lessons
1. Firm's Output Decisions Overview:
2. Total Revenue & Total Cost Curves
• 2 ways for markets to maximize profit
• Low output level $\,$$\,$ economic loss
• High output level $\,$$\,$ economic loss
• Intermediate output level $\,$$\,$ economic profits
• Find the output with the biggest gap
3. MC = MR
• Profit maximized when MC = MR
• MR > MC, economic profit $\, \uparrow \,$ when output $\, \uparrow \,$
• MR < MC, economic profit $\, \downarrow \,$ when output $\, \uparrow \,$
• MR = MC, economic profit $\, \downarrow \,$ when output $\, \uparrow \,$ or $\, \downarrow \,$
4. A Firm's Decision to Shutdown
• Calculating Economic Loss
• Shutdown $\,$$\,$ Firm must cover TFC
• Open $\,$$\,$ Firm must cover TFC & TVC
• Open when AVC < p, Close when AVC > p
• Shutdown Point when AVC = p
5. Firm's Supply Curve
• Market price varies, MR varies
• How much output firms make when price varies
##### Examples
###### Lessons
1. Maximizing Economic Profit, Analyzing Firm Operation, & Graphing Firm Supply Curves
Use the following table to answer the questions
 Output Total Cost 0 5 1 10 2 13 3 18 4 25 5 34
1. Calculate the profit-maximizing output and economic profit if the market price is $7. 2. What is the shutdown point? 3. What is the economic loss if the firm shuts down temporarily? 2. Use the following table to answer the questions  Output Total Cost 0 5 1 10 2 13 3 18 4 25 5 34 1. Calculate the profit-maximizing output and economic profit if the market price is$5.
2. Should the firm shut down or operate?
3. Consider the following graph

Find the profit-maximizing output & economic profit when the market price is:
1. $10 2.$20
4. Consider the following graph

Graph the firm's supply curve.

## Introduction to Perfect Competition Firm's Output Decisions

Welcome to our exploration of perfect competition and firm's output decisions! This fundamental concept in economics is crucial for understanding how businesses operate in highly competitive markets. Our introduction video sets the stage for a deep dive into this topic, providing you with a solid foundation. In perfect competition, firms are price takers, meaning they can't influence market prices. Instead, they focus on optimizing their output to maximize profits. We'll examine how firms make these critical decisions, balancing marginal revenue and marginal cost. You'll learn about the profit maximization rule and how it guides firms in determining their ideal production levels. As we progress, we'll also discuss the short-run and long-run implications of perfect competition on firm behavior. This knowledge is essential for grasping market dynamics and business strategies in competitive environments. Let's embark on this exciting journey to unravel the intricacies of perfect competition and firm decision-making!

## Maximizing Profit: Total Revenue and Total Cost Curves

### Understanding Profit Maximization

Hey there, future economists! Let's dive into the fascinating world of profit maximization using total revenue and total cost curves. This method is like a treasure map for businesses, helping them find the sweet spot where profits are at their peak. Ready to explore?

### The Total Revenue Curve

Imagine a line that shows how much money a company makes as it sells more products. That's our total revenue curve! It usually starts low and climbs up as sales increase. For example, if you're selling lemonade, your revenue grows with each glass sold.

### The Total Cost Curve

Now, picture another line representing all the costs involved in making and selling products. This is our total cost curve. It includes both fixed costs (like rent) and variable costs (like ingredients for our lemonade). This curve typically starts higher than the revenue curve (due to initial costs) and then rises as production increases.

### The Profit Maximization Graph

When we put these two curves together on one graph, magic happens! The space between them tells an important story:

• Where the total revenue curve is above the total cost curve, we're in the economic profit zone.
• Where the total cost curve is higher, we're looking at economic loss.
• The point where these curves are furthest apart? That's our profit maximization point!

### Economic Profit Region

In this happy place, our lemonade stand is making more money than it's spending. The gap between the revenue and cost curves represents pure profit. It's like finding extra change in your couch cushions, but on a business scale!

### Economic Loss Region

Uh-oh! When costs outweigh revenue, we're in the economic loss zone. It's like spending more on lemons than you're making from lemonade sales. Not ideal, but understanding this helps businesses know when to make changes.

### Finding the Sweet Spot

The goal is to find where the gap between total revenue and total cost is largest. This is where profits are maximized. On our graph, it's the point where the distance between the two curves is greatest. For our lemonade stand, it might be selling 100 glasses a day any more or less, and profits start to dip.

### Real-World Application

Let's say you're running a small bakery. At first, as you bake and sell more cakes, your revenue grows faster than your costs. But eventually, you might need to hire more staff or buy bigger ovens, causing your costs to rise more quickly. The point just before this happens is often where profits are highest.

### The Importance of This Method

Understanding this graphical method helps businesses:

• Visualize their financial situation
• Identify the optimal production level
• Recognize when they're operating at a loss
• Make informed decisions about scaling up or down

### Limitations to Consider

While this method is super helpful, remember it's a simplified model. In the real world, factors like market changes, competition, and consumer behavior can affect these curves. It's a great starting point, but always consider the bigger picture!

### Conclusion

Mastering the total revenue and total cost curve method is like having a superpower in the business world. It helps you understand when you're making money, losing money, and most importantly, when you're making the most money possible. Whether you're running a lemonade stand or dreaming of a Fortune 500 company, this tool will serve you well. Keep practicing, and soon you'll be a profit maximization pro!

## Profit Maximization: Marginal Revenue and Marginal Cost

### Understanding Marginal Revenue and Marginal Cost

The second method of profit maximization involves analyzing the relationship between marginal revenue (MR) and marginal cost (MC). This approach is crucial for firms to determine their optimal output level and maximize profits. Let's delve into these concepts and explore how they work in perfect competition.

### Marginal Revenue in Perfect Competition

In a perfectly competitive market, firms are price takers. This means that the price of their product is determined by market forces, and individual firms have no control over it. As a result, the marginal revenue curve in perfect competition is horizontal and equal to the market price. This unique characteristic simplifies the profit maximization process for firms operating in such markets.

### Marginal Cost Curve Characteristics

The marginal cost curve typically has a U-shape. Initially, as production increases, marginal costs may decrease due to economies of scale. However, as output continues to rise, marginal costs eventually start to increase. This is often due to factors such as diminishing returns or capacity constraints. Understanding the shape of the MC curve is crucial for firms to identify their optimal production level.

### Determining Optimal Output

To maximize profits, firms should produce at the level where marginal revenue equals marginal cost (MR = MC). This point represents the optimal output level. At this equilibrium:

• If MR > MC, the firm should increase production as each additional unit adds more to revenue than to costs.
• If MR < MC, the firm should decrease production as each additional unit adds more to costs than to revenue.
• When MR = MC, the firm has reached its profit-maximizing output level.

### The Profit Maximization Process

In perfect competition, the profit maximization process follows these steps:

1. Identify the market price, which is equal to marginal revenue.
2. Plot the marginal cost curve.
3. Find the point where the horizontal MR line intersects the MC curve.
4. The quantity at this intersection point is the optimal output level.

### Short-Run vs. Long-Run Considerations

It's important to note that the MR = MC rule applies in both the short run and long run. However, in the long run, firms have more flexibility to adjust their production capacity. This can lead to changes in the shape of the MC curve and, consequently, the optimal output level.

### Practical Applications

While the MR = MC approach is theoretically sound, its practical application can be challenging. Firms often face difficulties in accurately measuring marginal costs and revenues. However, understanding this principle helps managers make informed decisions about production levels and pricing strategies.

### Beyond Perfect Competition

Although we've focused on perfect competition, the MR = MC rule applies to other market structures as well. In monopolistic or oligopolistic markets, the marginal revenue curve is not horizontal, which adds complexity to the analysis. Firms in these markets must consider how their output decisions affect market prices.

### Conclusion

The marginal revenue and marginal cost approach to profit maximization is a powerful tool for firms to optimize their production decisions. By understanding the characteristics of MR and MC curves and applying the MR = MC rule, businesses can identify their ideal output level. This method, combined with other economic analyses, helps firms navigate the complexities of market dynamics and achieve their financial goals.

## Firm's Shutdown Decision

Understanding how firms decide whether to shut down or continue operating is crucial in economics. This decision-making process involves analyzing costs, revenues, and market conditions. Let's dive into this topic with a friendly, tutoring approach to grasp the key concepts and their significance.

First, let's consider the concept of economic loss. A firm experiences economic loss when its total revenue is less than its total cost. The formula for economic loss is:

Economic Loss = Total Cost - Total Revenue

However, just because a firm is experiencing economic loss doesn't necessarily mean it should shut down immediately. This is where the concept of average variable cost (AVC) comes into play.

Average variable cost is the variable cost per unit of output. It's calculated by dividing total variable costs by the quantity produced. AVC is crucial in the shutdown decision because it represents the costs that can be avoided if the firm ceases production.

Now, let's introduce the shutdown point. The shutdown point is the price level at which a firm is indifferent between operating and shutting down in the short run. It occurs when the price equals the minimum average variable cost. At this point, the firm is just covering its variable costs but not its fixed costs.

Here's the key decision rule: If the market price is above the average variable cost, the firm should continue operating in the short run, even if it's incurring an economic loss. Why? Because by operating, the firm can at least cover its variable costs and part of its fixed costs. On the other hand, if the market price falls below the average variable cost, the firm should shut down temporarily to minimize its losses.

Let's illustrate this with an example. Imagine you own a small bakery. Your total fixed costs (rent, equipment, etc.) are $1,000 per month. Your variable costs (ingredients, electricity, etc.) are$2 per loaf of bread. If you're producing 500 loaves per month, your average variable cost is $2 per loaf. Scenario 1: The market price for a loaf of bread is$2.50. Even though you're not covering all your fixed costs, you should continue operating because you're covering your variable costs and part of your fixed costs. Your loss by operating ($750) is less than your loss if you shut down ($1,000 in fixed costs).

Scenario 2: The market price drops to $1.80 per loaf. Now, you're not even covering your variable costs. In this case, you should shut down temporarily because your losses would be greater if you continued operating. The significance of the shutdown point lies in its role as a critical threshold for business decisions. It helps firms minimize losses in the short run when market conditions are unfavorable. By understanding this concept, businesses can make informed decisions about whether to weather temporary market downturns or cease operations to cut losses. It's important to note that the shutdown decision we've discussed applies to the short run. In the long run, all costs become variable, and firms have more flexibility to adjust their operations or exit the market entirely if they can't cover all their costs. To summarize, the shutdown decision involves comparing the market price to the average variable cost. The shutdown point occurs when price equals minimum AVC. Firms should continue operating as long as they can cover their variable costs, even if they're incurring an economic loss. This approach allows them to minimize losses in the short run by covering some fixed costs. Understanding these concepts empowers businesses to make sound economic decisions, especially during challenging market conditions. By carefully analyzing costs and market prices, firms can navigate through difficult periods and position themselves for long-term success. ## The Firm's Supply Curve in Perfect Competition In the realm of perfect competition, understanding the firm's supply curve is crucial for grasping how businesses make production decisions. This concept is intricately linked to the marginal cost curve and the shutdown point, playing a pivotal role in determining a firm's profit maximization strategy. The firm's supply curve in perfect competition represents the quantity of goods a company is willing to produce at various market prices. Interestingly, this curve is not a separate entity but is actually derived from the firm's marginal cost curve. To comprehend this relationship, we need to delve into the concept of marginal cost and its significance in the decision-making process of firms. Marginal cost refers to the additional cost incurred by producing one more unit of output. In a perfectly competitive market, firms are price takers, meaning they cannot influence the market price. As such, they aim to maximize profits by producing at a level where the marginal cost equals the market price. This point of intersection between the marginal cost curve and the market price line determines the optimal quantity of production for the firm. Now, let's visualize this concept. Imagine a graph with price on the vertical axis and quantity on the horizontal axis. The marginal cost curve typically has a U-shape, reflecting increasing marginal returns in the early stages of production, followed by diminishing returns as output expands. The firm's supply curve is the portion of the marginal cost curve that lies above the average variable cost curve. Why does the supply curve start from this point? This brings us to the concept of the shutdown point. The shutdown point is the price level at which the firm's total revenue equals its total variable costs. If the market price falls below this point, the firm is better off shutting down production in the short run to minimize losses. Graphically, this point occurs where the average variable cost curve intersects with the marginal cost curve. To illustrate this with an example, let's consider a small bakery operating in a perfectly competitive market for bread. At a market price of$2 per loaf, if the bakery's marginal cost of producing the 100th loaf is also $2, this would be the optimal production level. If the price rises to$2.50, the bakery would increase production until the marginal cost of the last loaf equals $2.50, perhaps at 120 loaves. Conversely, if the price drops to$1.50, the bakery would reduce production, possibly to 80 loaves.

However, if the market price falls below the bakery's average variable cost, say to \$1 per loaf, and this is expected to persist, the bakery would consider shutting down temporarily. In this scenario, by ceasing production, the bakery avoids variable costs and only incurs fixed costs, potentially minimizing losses.

It's important to note that the firm's supply curve in perfect competition is always upward sloping. This characteristic reflects the law of diminishing returns as a firm produces more, it typically faces higher marginal costs, requiring a higher price to justify increased production.

Understanding the firm's supply curve helps in analyzing market dynamics. In aggregate, these individual firm supply curves contribute to the industry supply curve. When market demand increases, leading to higher prices, firms respond by moving up their supply curves, increasing production. This responsiveness to price changes is a key feature of perfectly competitive markets, ensuring efficient allocation of resources.

In conclusion, the firm's supply curve in perfect competition is a fundamental concept in microeconomics. Its direct relationship with the marginal cost curve and the critical role of the shutdown point in decision-making highlight the complex interplay of factors influencing a firm's production choices. By grasping these concepts, we gain insight into how firms operate in competitive markets, striving for profit maximization while navigating the challenges of variable costs and market prices. This understanding is not just theoretical but has practical implications for business strategy and market analysis in real-world scenarios.

## Short-run vs. Long-run Decisions in Perfect Competition

Hey there, economics enthusiast! Today, we're diving into the fascinating world of perfect competition and exploring how firms make decisions in both the short run and long run. Let's break it down in a way that's easy to understand and remember.

First, let's talk about short-run decisions. In the short run, firms in perfect competition face some fixed constraints. Imagine you're running a small bakery. Your kitchen size, ovens, and some staff are fixed costs you can't quickly change. These are your short-run constraints.

In this short-run scenario, your main decision is how much to produce given these fixed factors. You'll want to produce at a level where your marginal cost (the cost of making one more unit) equals the market price. Why? Because in perfect competition, you're a price taker you can't influence the market price.

Now, let's shift gears to long-run decisions. This is where things get really interesting! In the long run, all factors of production become variable. Going back to our bakery example, you now have the flexibility to change everything kitchen size, number of ovens, staff size, even location.

The key long-run decisions for firms in perfect competition revolve around two main questions: Should we adjust our output? And should we stay in the market or exit?

Let's talk about adjusting output first. In the long run, firms aim to produce at the point where their long-run average cost is at its minimum. This is called the minimum efficient scale. It's like finding the sweet spot where you're operating most efficiently.

Now, onto the big decision of market entry or exit. This is where the concept of economic profit comes into play. In perfect competition, if firms are making economic profits (profits above normal returns), it attracts new firms to enter the market. Think of it like a gold rush when there's money to be made, everyone wants in!

On the flip side, if firms are making economic losses, some will exit the market. It's like a game of musical chairs, but with businesses. Those who can't keep up eventually leave.

Here's the cool part: this process of entry and exit continues until economic profits are driven to zero. At this point, we reach what's called long-run equilibrium. It's a balancing act where firms are making just enough to stay in business, but not so much that it attracts a flood of new competitors.

Let's use another example to illustrate this. Imagine a boom in the demand for organic smoothies. In the short run, existing smoothie shops might increase their production and enjoy some profits. But in the long run, new organic smoothie shops will pop up, increasing supply and bringing prices (and profits) back down.

The key difference between short-run and long-run decisions is the flexibility firms have. In the short run, they're working with what they've got. In the long run, they can change everything about their operation and even decide whether to stay in the game.

It's also worth noting that in perfect competition, firms are always pushed towards efficiency. The constant threat of new entrants and the ease of exit mean that only the most efficient firms survive in the long run. It's like natural selection, but for businesses!

Remember, perfect competition is an ideal model. In the real world, markets are rarely perfectly competitive. But understanding this model helps us grasp important economic concepts and how markets tend to work in the absence of complications like barriers to entry or product differentiation.

So, next time you're sipping on that organic smoothie or biting into a freshly baked croissant, think about the short-run and long-run decisions that went into bringing that product to you. It's a complex dance of supply, demand, and strategic decision-making that keeps our markets humming along.

In conclusion, while short-run decisions in perfect competition focus on optimizing output with fixed constraints, long-run decisions involve more fundamental choices about scale, efficiency, and market participation. The interplay between these decisions drives markets towards efficiency and equilibrium, showcasing the dynamic nature of competitive markets. Keep these concepts in mind, and you'll have a deeper appreciation for the economic forces at work in the world around you!

## Conclusion: Key Takeaways on Perfect Competition Firm's Output Decisions

In this article, we've explored the crucial concepts of perfect competition, profit maximization, and the shutdown decision, which are fundamental to understanding a firm's supply curve. For economics students, grasping these principles is essential for building a strong foundation in microeconomics. We've seen how firms in perfect competition markets make output decisions based on marginal costs and market prices, always aiming to maximize profits or minimize losses. The shutdown point and its role in determining a firm's short-run supply curve are particularly important concepts to master. The introduction video provided a valuable visual aid to complement these ideas. As you continue your economics journey, remember that these concepts are not just theoretical but have real-world applications in understanding market dynamics. We encourage you to further explore these topics, discuss them with peers, and apply them to various economic scenarios. Your understanding of perfect competition will serve as a stepping stone to more complex market structures.

### Firm's Output Decisions Overview:

Firm's Output Decisions Overview: Total Revenue & Total Cost Curves

• 2 ways for markets to maximize profit
• Low output level economic loss
• High output level economic loss
• Intermediate output level economic profits
• Find the output with the biggest gap

#### Step 1: Introduction to Perfect Competition and Profit Maximization

In a perfectly competitive market, firms aim to maximize their profit. There are two primary methods to achieve this goal. The first method involves examining the total revenue and total cost curves, while the second method focuses on finding the output level where marginal revenue equals marginal cost. This guide will delve into the first method in detail.

#### Step 2: Understanding Total Revenue and Total Cost Curves

To maximize profit, firms need to analyze the total revenue and total cost curves. The total revenue curve is typically a straight line, while the total cost curve is more complex, often resembling a squiggly line. By graphing these curves, firms can identify different output levels and their corresponding economic outcomes.

#### Step 3: Identifying Economic Loss at Low and High Output Levels

When the total revenue is less than the total cost, firms experience an economic loss. This scenario usually occurs at low and high levels of output production. At low output levels, the cost of production exceeds the revenue generated, leading to a loss. Similarly, at high output levels, the increased costs outweigh the revenue, resulting in another economic loss.

#### Step 4: Recognizing Economic Profit at Intermediate Output Levels

Economic profit occurs when the total revenue exceeds the total cost. This typically happens at intermediate levels of output production. By producing at these levels, firms can ensure that their revenue surpasses their costs, leading to economic profit. The goal is to find the output level within this range that maximizes the profit.

#### Step 5: Finding the Output with the Biggest Gap

To maximize profit, firms need to identify the output level where the gap between total revenue and total cost is the largest. This gap represents the maximum economic profit. By graphing the total revenue and total cost curves, firms can visually determine the point where this gap is the widest.

#### Step 6: Graphing the Economic Profit Curve

Another useful tool is the economic profit curve, which can be derived by subtracting the total cost curve from the total revenue curve. This curve typically resembles an upside-down U shape. The peak of this curve represents the output level that maximizes profit. By identifying this point, firms can determine the optimal output level for profit maximization.

#### Step 7: Conclusion and Practical Application

In summary, firms in a perfectly competitive market can maximize their profit by analyzing the total revenue and total cost curves. By identifying the output levels that lead to economic loss and profit, and finding the point with the largest gap between revenue and cost, firms can determine the optimal production level. Additionally, graphing the economic profit curve provides a clear visual representation of the profit-maximizing output level.

### FAQs

1. #### What happens if a firm shuts down in the short run?

When a firm shuts down in the short run, it temporarily ceases production but retains its fixed assets. The firm stops incurring variable costs but continues to pay fixed costs. This decision is made when the market price falls below the average variable cost, making it more economical to halt production than to operate at a loss.

2. #### What costs do firms that shut down in the short run still have to pay?

Firms that shut down in the short run still have to pay their fixed costs. These typically include rent, property taxes, insurance, loan payments, and salaries for essential personnel. Variable costs, such as raw materials and hourly wages, are avoided during the shutdown period.

3. #### What does a firm that exits the market have to pay?

When a firm exits the market completely (long-run decision), it generally doesn't have ongoing costs. However, it may incur exit costs such as contract termination fees, severance payments to employees, and costs associated with liquidating assets. Any remaining debt obligations must also be settled.

4. #### How do firms in competitive markets determine their optimal output level?

Firms in competitive markets determine their optimal output level by producing where marginal cost (MC) equals the market price (P), which is also equal to marginal revenue (MR) in perfect competition. This point maximizes profits or minimizes losses. If P > MC, the firm should increase production; if P < MC, it should decrease production.

5. #### What is the difference between a firm's short-run and long-run supply curve in perfect competition?

The short-run supply curve in perfect competition is the portion of the marginal cost curve above the average variable cost curve. It reflects the firm's output decisions given fixed factors of production. The long-run supply curve, however, is perfectly elastic (horizontal) at the minimum of the long-run average cost curve, as firms can adjust all factors of production and enter or exit the market freely.

### Prerequisite Topics

Understanding the concept of perfect competition firm's output decisions is crucial for students of economics and business. While there are no specific prerequisite topics provided for this subject, it's important to recognize that a strong foundation in basic economic principles is essential for grasping this more advanced concept.

To fully comprehend perfect competition firm's output decisions, students should have a solid understanding of supply and demand dynamics, market structures, and basic microeconomic principles. These fundamental concepts serve as building blocks for more complex economic theories and models.

One key aspect to consider is the nature of perfect competition itself. In a perfectly competitive market, firms are price takers, meaning they have no control over the market price. This concept is crucial for understanding how firms make output decisions in such an environment. Students should be familiar with the characteristics of perfect competition, including a large number of buyers and sellers, homogeneous products, and free entry and exit from the market.

Another important area to grasp is the concept of marginal analysis. Firms in perfect competition make output decisions based on marginal costs and marginal revenues. Understanding how to calculate and interpret these marginal values is essential for determining the profit-maximizing output level.

Cost analysis is also a critical component of this topic. Students should be comfortable with various cost concepts, such as fixed costs, variable costs, average costs, and total costs. These cost structures play a significant role in a firm's decision-making process regarding output levels.

Furthermore, knowledge of profit maximization strategies is vital. Firms in perfect competition aim to maximize their profits, and understanding how to determine the point where marginal revenue equals marginal cost is key to this process.

While specific prerequisite topics are not provided, students should ensure they have a strong grasp of these fundamental economic concepts before delving into the intricacies of perfect competition firm's output decisions. A solid foundation in these areas will greatly enhance their ability to analyze and understand the decision-making processes of firms in perfectly competitive markets.

By building upon these core economic principles, students will be better equipped to explore the nuances of perfect competition and how firms navigate this unique market structure to make informed output decisions. This comprehensive understanding will not only aid in academic success but also provide valuable insights into real-world economic scenarios and business strategies.

There are 2 ways for firms to maximize profits:
1. Examine the Total Revenue & Total Cost curves
2. Find the output of when MR = MC

Total Revenue & Total Cost Curves

When examining the total revenue and total cost curves, we want to see which outputs give economic loss, and economic profit.

When TR < TC, when we have an economic loss. This happens at low and high levels of output production.

When TR = TC, we gain no profit and no loss. Then happens when the curves intersect.

When TR > TC, we gain economic profit. This happens at intermediate levels of output production.

Goal: Find an intermediate level of output that maximizes profit. In other words, find the biggest gap between TR & TC!

Note: We can also graph the economic profit curve (P = TR - TC), and find the point with the highest economic profit!

MC = MR

Recall that the marginal revenue (firms demand curve) is horizontal.

In addition, the marginal cost decreases as output increases in the beginning, and then increases afterwards.

Therefore, we get the following graph.

If MR > MC, economic profit increases as output increases.

If MR < MC, economic profit decreases as output increases.

If MR < MC, economic profit does not change if output increases or decreases. Profit is maximized here.

A Firms Decision to Shutdown

To see if a firm should stay open or shut down, we need to know how to calculate the economic loss of a firm.

Economic Loss = TFC + TVC - TR
= TFC + (AVC x q) - (p x q)
= TFC + (AVC - p) x q

When the firm decides to shutdown, then q = 0, and the economic loss is TFC. If the firm stay open, then q > 0, and the firm would have to pay both TFC and TVC.

The firm should stay open when AVC < p .

The firm should shut down when AVC > p .

The firm is indifferent about staying open and shutting down when AVC = p . This is also known as the shutdown point.

Note: Graphically, the shutting down is at the minimum of the AVC curve and intersects the MC curve.

Firms Supply Curve

A firms supply curve shows the firms profit-maximizing output as the market price varies.

When the market price varies, the MR $\,$ shifts, causing the intersection of MR = MC $\,$ to change. All the intersection points create the firms supply curve.

Note: The firms supply curve starts at the shutdown point because thats when the firm starts producing output to reduce economic loss or gain profit.