Microeconomics Core Concepts: Study Guide

Capital and Factors of Production

Definition of Capital

In economics, capital refers to the man-made resources used in the production of goods and services. This includes machinery, buildings, tools, and equipment.

• Physical capital: Tangible assets like machines and factories.

• Human capital: Skills and knowledge of workers.

• Financial capital: Funds used to acquire physical or human capital.

Example: A bakery's ovens and mixers are its physical capital.

Unregulated Markets and the Role of Prices

Advantages of Unregulated (Free) Markets

• Efficient allocation of resources through the price mechanism.

• Encourages innovation and entrepreneurship.

• Consumer sovereignty: consumers decide what is produced.

Role of Prices in a Free Market

• Prices act as signals to both buyers and sellers.

• High prices encourage production; low prices discourage it.

• Prices help balance supply and demand, leading to market equilibrium.

Example: If the price of smartphones rises, more firms may enter the market to supply them.

Economic Agents: Firms, Entrepreneurs, Households, and Factors

Definitions

• Firms: Organizations that produce goods or services for profit.

• Entrepreneurs: Individuals who organize resources and take risks to create new products or businesses.

• Households: Consumers who provide factors of production (labor, capital, land) and purchase goods/services.

• Factors of production: Land, labor, capital, and entrepreneurship.

Roles in Output and Input Markets

• Households: Supply factors of production in input markets; demand goods/services in output markets.

• Firms: Demand factors of production in input markets; supply goods/services in output markets.

Inferior Goods and Income Changes

Definition of Inferior Good

An inferior good is a good for which demand decreases as consumer income rises.

• Example: Generic brand groceries may be considered inferior goods.

• If income increases, demand for inferior goods falls.

Utility and Marginal Utility

Marginal Utility

Marginal utility is the additional satisfaction gained from consuming one more unit of a good or service.

• Calculated as the change in total utility divided by the change in quantity consumed.

Formula:

$MU = \frac{\Delta TU}{\Delta Q}$

where $MU$ is marginal utility, $TU$ is total utility, and $Q$ is quantity.

Profit and Revenue Concepts

Definition of Profit

Profit is the difference between total revenue and total costs.

• Economic profit: Includes both explicit and implicit (opportunity) costs.

• Accounting profit: Only considers explicit costs.

Formula:

$\text{Economic Profit} = \text{Total Revenue} - \text{Total Economic Costs}$

Perfect Competition and Price Setting

Price in a Perfectly Competitive Market

• Firms are price takers; they cannot set the price.

• The market determines the price; each firm sells at this price.

Example: Wheat farmers sell at the market price, not a price they choose.

Short Run vs. Long Run in Production

The Short Run

• At least one input is fixed (e.g., factory size).

• Firms may be 'stuck with' fixed costs like rent or equipment leases.

The Long Run

• All inputs are variable; firms can adjust all factors of production.

• Firms can enter or exit the industry.

Production and Cost Concepts

Optimal Method of Production

• The optimal method minimizes costs for a given output.

Diminishing Marginal Returns

• As more units of a variable input are added to fixed inputs, the additional output from each new unit eventually decreases.

Marginal Cost

• The increase in total cost from producing one more unit of output.

Formula:

$MC = \frac{\Delta TC}{\Delta Q}$

Total, Fixed, and Variable Costs

• Total cost (TC): Sum of fixed and variable costs.

• Fixed cost (FC): Costs that do not change with output (e.g., rent).

• Variable cost (VC): Costs that change with output (e.g., materials).

Formulas:

$TC = FC + VC$

$AVC = \frac{VC}{Q}$

$AFC = \frac{FC}{Q}$

$ATC = \frac{TC}{Q}$

Marginal Revenue

• The additional revenue from selling one more unit of output.

Formula:

$MR = \frac{\Delta TR}{\Delta Q}$

Market Entry, Exit, and Profit in Perfect Competition

Free Entry and Exit

• Firms can enter or leave the market without barriers.

• Ensures long-run economic profit is zero in perfect competition.

Profit and Market Dynamics

• Firms enter if existing firms earn positive economic profit, increasing industry supply and lowering price.

• Firms exit if they incur losses, decreasing supply and raising price.

Shut Down and Stay Open Decisions

• Short run: Stay open if price covers variable costs ($P \geq AVC$).

• Long run: Stay open only if price covers total costs ($P \geq ATC$).

Productivity and Marginal Product

Productivity

• Output per unit of input (e.g., labor productivity = output per worker).

Marginal Product

• The additional output from hiring one more unit of input.

Formula:

$MP = \frac{\Delta Q}{\Delta L}$

Example: If 1 worker produces 20 units and 2 workers produce 35 units, the marginal product of the second worker is 15 units.

Opportunity Cost and Surplus Concepts

Opportunity Cost

• The value of the next best alternative foregone when making a choice.

Example: If you use resources to make product A instead of product B, the opportunity cost is the value of product B.

Consumer and Producer Surplus

• Consumer surplus: Difference between what consumers are willing to pay and what they actually pay.

• Producer surplus: Difference between the price received and the minimum price at which producers are willing to sell.

Cost Calculations from Charts

Reading Cost Data

• Be able to identify variable, marginal, total, average, and fixed costs from tables.

• Fixed costs remain constant regardless of output.

• Variable costs increase with output.

• Marginal cost is the change in total cost for each additional unit produced.

Profit Maximization in Perfect Competition

Profit Maximization Rule

• Firms maximize profit where marginal cost equals marginal revenue ($MC = MR$).

• In perfect competition, $MR = P$ (market price).

Should a firm keep producing? Yes, if $P \geq AVC$ in the short run; otherwise, shut down.

Demand Curve in Perfect Competition

• The demand curve facing an individual firm is perfectly elastic (horizontal) at the market price.

Marginal Revenue Product

Definition

• The additional revenue generated from employing one more unit of input (e.g., a worker).

Formula:

$MRP = MP \times MR$

Production Possibility Frontier (PPF)

Points on, Below, and Outside the PPF

• On the PPF: Efficient use of resources.

• Below the PPF: Inefficient use of resources.

• Outside the PPF: Unattainable with current resources and technology.

Technological Advances

• Shift the PPF outward, allowing more production of both goods.

Elasticity of Demand

Price Elasticity of Demand

• Measures responsiveness of quantity demanded to a change in price.

Formula:

$E_d = \frac{\%\ \text{change in Q}}{\%\ \text{change in P}}$

• Elastic: $|E_d| > 1$ (quantity changes more than price).

• Inelastic: $|E_d| < 1$ (quantity changes less than price).

Effect on Total Revenue: If demand is elastic, a price increase lowers total revenue; if inelastic, a price increase raises total revenue.

Substitutes and Elasticity

• More substitutes make demand more elastic.

Labor-Leisure Tradeoff

Price of Leisure

• The opportunity cost of leisure is the wage foregone by not working.

Average Costs and Long Run Average Cost Curve

Finding Average Costs

• Average total cost (ATC): $ATC = \frac{TC}{Q}$

• Average variable cost (AVC): $AVC = \frac{VC}{Q}$

• Average fixed cost (AFC): $AFC = \frac{FC}{Q}$

Long Run Average Cost Curve

• Shows the lowest possible cost of producing each output level when all inputs are variable.

• Can exhibit economies or diseconomies of scale.

Economies of Scale

• When increasing production lowers average cost.

• Due to factors like specialization and bulk purchasing.

Shifting Demand and Supply Curves

Shifting Demand Curve

• Rightward shift: Increase in demand at every price.

• Leftward shift: Decrease in demand at every price.

Shifting Supply Curve

• Rightward shift: Increase in supply at every price.

• Leftward shift: Decrease in supply at every price.

How to read shifts: At a given price, compare the new and old quantity supplied or demanded.

Budget Constraint and Opportunity Cost

Budget Constraint

• Shows all combinations of goods a consumer can afford given income and prices.

• Moves outward with increased income or lower prices; inward with decreased income or higher prices.

Opportunity Cost Along a Budget Line

• Spending more on one good means giving up units of another good.

Marginal Revenue Product and Productivity

• If a worker becomes more productive, their marginal revenue product increases.

Marginal Utility from Total Utility Graph

• Marginal utility is the slope of the total utility curve at each quantity.

• Represents the extra utility from consuming one more unit.

Sample Table: Cost Concepts

Purpose: To compare different cost measures for a firm at various output levels.

Output (Q)	Fixed Cost (FC)	Variable Cost (VC)	Total Cost (TC)	Marginal Cost (MC)	Average Total Cost (ATC)
0	100	0	100	-	-
1	100	50	150	50	150
2	100	90	190	40	95
3	100	120	220	30	73.33
4	100	160	260	40	65

Additional info: Table values are illustrative; actual numbers may vary in specific problems.