📖 Chapter 2: Microeconomics: Supply and Demand

What this chapter covers: This chapter focuses on the fundamental principles of supply and demand in microeconomics. It covers competitive markets, market equilibrium, and the impact of government interventions like taxes and subsidies. The goal is to understand how prices and quantities are determined in markets.

🔑 Essential Concepts & Applications

🛠️ Problem Solving

Problem Type A: Determining Market Equilibrium Setup: "When given supply and demand equations." Method: "Set quantity demanded equal to quantity supplied and solve for price and quantity." Example: "If Qd = 100 - 2P and Qs = 3P, then 100 - 2P = 3P, so P = 20 and Q = 60."

Problem Type B: Calculating Price Elasticity of Demand Setup: "If given percentage changes in price and quantity demanded." Method: "Use the formula: PED = (% change in quantity demanded) / (% change in price)." Example: "If price increases by 10% and quantity demanded decreases by 5%, then PED = -5%/10% = -0.5."

🧮 Solved Example

Problem: Suppose the demand function is Qd = 10 - P and the supply function is Qs = P. Find the equilibrium price and quantity.

Given:

• Qd = 10 - P
• Qs = P

Steps:

1. Set Qd = Qs: 10 - P = P
2. Solve for P: 2P = 10 => P = 5
3. Substitute P into either equation to find Q: Q = 5

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✅

Answer: Equilibrium Price = 5, Equilibrium Quantity = 5

⚠️ Common Mistakes

❌ Mistake 1: Confusing a change in quantity demanded with a change in demand. ✅ How to avoid: A change in price causes a movement along the demand curve (change in quantity demanded), while a change in other factors causes a shift of the demand curve (change in demand).

❌ Mistake 2: Incorrectly calculating elasticity due to using the wrong formula or not understanding percentage changes. ✅ How to avoid: Use the correct formula: PED = (% change in quantity demanded) / (% change in price).

📖 Chapter 3: Market Failure and Externalities

What this chapter covers: This chapter addresses market failures, particularly externalities, and explores policies to correct them. It covers both positive and negative externalities and how they lead to inefficient resource allocation.

🔑 Essential Concepts & Applications

🛠️ Problem Solving

Problem Type A: Identifying Externalities Setup: "When given a scenario involving production or consumption." Method: "Determine if there are any costs or benefits imposed on third parties not involved in the transaction." Example: "A factory polluting a river imposes a negative externality on downstream users."

Problem Type B: Analyzing the Effects of Corrective Taxes Setup: "If given a market with a negative externality and a corrective tax." Method: "Show how the tax shifts the supply curve, reducing output and internalizing the externality." Example: "A carbon tax on coal-fired power plants increases their production costs, leading to reduced electricity output and lower pollution levels."

🧮 Solved Example

Problem: A factory emits pollution that causes $10 of damage per unit produced. Without intervention, the factory produces 100 units. If a$10 tax per unit is imposed, the factory reduces production to 80 units. Calculate the reduction in external costs.

Given:

• External cost per unit: $10
• Initial production: 100 units
• Production after tax: 80 units

Steps:

1. Calculate initial external cost: 100 units * $10/unit =$1000
2. Calculate external cost after tax: 80 units * $10/unit =$800
3. Calculate reduction in external costs: $1000 -$800 = $200

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✅

Answer: The reduction in external costs is $200.

⚠️ Common Mistakes

❌ Mistake 1: Failing to distinguish between private costs and social costs. ✅ How to avoid: Social cost includes private cost plus external cost.

❌ Mistake 2: Assuming that all government intervention is beneficial. ✅ How to avoid: Evaluate the costs and benefits of each policy intervention.