ECO2003F Microeconomics II Detailed Notes (UCT Economics Study Guide)

ECO2003F—Microeconomics II—extends the core consumer and firm foundations from introductory microeconomics into deeper topics such as market structure, welfare analysis, uncertainty and risk, intertemporal choice, and strategic behaviour. This study guide is written for students in the University of Cape Town (UCT) Economics programme and is designed to help you build exam-ready reasoning: you should be able to move from definitions to diagrams to algebra and then to welfare and policy conclusions.

Across the five sections below, the notes connect standard micro theory (often tested through problem sets and exam questions) with the typical South African university approach: careful assumptions, disciplined use of marginal analysis, and clarity about equilibrium concepts. The guide also emphasizes how to show work in assignments—because many marks come from the method, not only the final answer.

1. Market Structures: Monopolistic Competition, Oligopoly, and Strategic Interaction (ECO2003F Foundations)

1.1 Why market structure matters (and what exams look for)

In Microeconomics II, “market structure” is not treated as memorization of labels (perfect competition vs monopoly vs monopolistic competition). Instead, you are expected to connect structure → incentives → equilibrium → welfare.

Exams typically test one or more of the following chains:

1. Assumptions about demand and competition
2. Firm’s marginal decision problem (MR=MC, pricing rule, or game-theoretic best responses)
3. Equilibrium outcome (quantity/price, profits, entry/exit, strategic moves)
4. Welfare implications (consumer surplus, producer surplus, deadweight loss, efficiency)

A frequent UCT-style assessment approach is: “Given a cost structure and a form of demand, derive the equilibrium; then interpret with welfare triangles and/or elasticities.”

1.2 Monopolistic competition: long-run equilibrium and excess capacity

In monopolistic competition, many firms sell differentiated products, so each firm faces a downward-sloping demand curve, but entry is possible. In the short run, firms act like monopolists: they choose output where MR = MC and typically earn positive economic profit.

Key logic to remember

• Short run: possible economic profit.
• Entry in the long run: economic profit attracts new firms.
• Demand shifts left for existing firms as variety expands and customers diversify.
• Long run: economic profit becomes zero.

Diagram interpretation (what you must be able to explain in words)

In the long run for monopolistic competition:

• The firm produces where MR = MC.
• That output is associated with a price such that P = ATC (zero economic profit).
• Yet P > MC, so allocative inefficiency persists.

That means:

• Productive inefficiency: firms operate with excess capacity because output is not at the minimum of ATC.
• Allocative inefficiency: price exceeds marginal cost.

Concrete numerical example (useful for exam arithmetic)

Suppose a firm has marginal cost:

• ( MC(q) = 2q )

Demand for its product:

• ( P(q) = 20 – q )

Then revenue:

• ( TR(q) = P(q)\cdot q = (20-q)q = 20q – q^2 )
• ( MR(q) = \frac{dTR}{dq} = 20 – 2q )

Set MR = MC:

• ( 20 – 2q = 2q \Rightarrow 20 = 4q \Rightarrow q^* = 5 )

Price:

• ( P^* = 20 – 5 = 15 )

If ATC at (q=5) is, say, 15, then long-run equilibrium requires:

• ( P = ATC \Rightarrow 15 = 15 \Rightarrow ) zero economic profit.

Welfare conclusion:

• Since ( MC(5) = 2\cdot 5 = 10 ) and ( P=15 ), we have (P>MC) and thus deadweight loss relative to the efficient level where (P=MC).

In an exam answer, you would:

1. Derive (q^) and (P^).
2. Compute (MC(q^*)).
3. Compare to (P) to show inefficiency.

1.3 Oligopoly and the need for game theory

For oligopoly, interdependence is crucial: each firm’s best output depends on rivals’ output. That is why economics shifts from single-agent optimization (like monopoly) toward strategic decision-making.

A typical question might ask you to use either:

• Cournot (quantity competition),
• Bertrand (price competition with/without differentiation),
• or a game matrix (prisoner’s dilemma, coordination games, entry deterrence).

1.4 Cournot duopoly: best responses and equilibrium

Two firms choose quantities (q_1, q_2). Market price depends on total quantity:

• ( P = a – b(q_1+q_2) )

Firm i profit:

• ( \pi_i = P\cdot q_i – C(q_i) )

Assume constant marginal cost (c) and no fixed cost for clarity:

• ( C(q_i)=cq_i )

Then:

• ( \pi_i = (a-b(q_1+q_2))q_i – cq_i )

To find firm i’s best response, differentiate w.r.t. (q_i):

• ( \pi_i = (a – bq_i – bq_{-i})q_i – cq_i = aq_i – bq_i^2 – bq_{-i}q_i – cq_i )
• ( \frac{d\pi_i}{dq_i} = a – 2bq_i – bq_{-i} – c = 0 )

So:

• ( 2bq_i = a – c – bq_{-i} )
• ( q_i = \frac{a-c}{2b} – \frac{1}{2}q_{-i} )

In symmetric equilibrium with (q_1=q_2=q):

• ( q = \frac{a-c}{2b} – \frac{1}{2}q \Rightarrow \frac{3}{2}q = \frac{a-c}{2b} \Rightarrow q = \frac{a-c}{3b} )

Total quantity:

• ( Q = q_1+q_2 = \frac{2(a-c)}{3b} )

This is exam-critical because it lets you compute:

• price (P = a – bQ)
• profits
• welfare comparisons with monopoly and perfect competition.

Example with numbers

Let (a=100), (b=1), (c=20).

Then each firm:

• ( q = \frac{100-20}{3\cdot 1} = \frac{80}{3} \approx 26.67 )

Total:

• ( Q \approx 53.33 )

Price:

• ( P = 100 – 1\cdot 53.33 = 46.67 )

MC is 20, so (P>MC): still inefficient relative to the competitive benchmark (P=MC).

1.5 Bertrand competition: price-setting and the knife-edge result

In Bertrand with identical products and constant marginal cost:

• If firms set prices simultaneously and choose the lowest price wins all demand,
• then the Nash equilibrium is often (P=c) (the “Bertrand paradox”), matching perfect competition despite having only two firms.

But exams may also ask: what happens if products are differentiated or if there are capacity constraints?

Why differentiation changes everything

If products are differentiated, demand depends on both prices and the “lowest price wins all” assumption breaks down. Then equilibrium typically yields (P>c) and positive market power.

1.6 Strategy games and Nash equilibrium: showing best responses

Many ECO2003F exam questions involve a game table like:

	Rival: A	Rival: B
You: A	(x,x)	(y,z)
You: B	(z,y)	(w,w)

To solve:

1. Identify your best response in each rival case.
2. Identify rival’s best response in each of your cases.
3. Nash equilibrium is where choices are mutual best responses.

Prisoner’s dilemma structure (conceptual)

• Dominant strategies can lead to a non-cooperative outcome worse for both players than the cooperative outcome.
• If a question gives payoff numbers, compute:
  • Nash equilibrium (non-cooperative),
  • Pareto-superior alternative (cooperation),
  • discuss policy relevance (commitment mechanisms, enforcement, repeated games).

2. Welfare Analysis, Externalities, Public Goods, and Policy Instruments

2.1 Consumer and producer surplus: efficient benchmarks

Welfare analysis is not optional in Microeconomics II. Even when the question is about market structure or strategy, an exam marker often expects you to know how to evaluate whether outcomes are efficient.

Start with benchmarks:

• Efficient allocation occurs where marginal willingness to pay equals marginal cost for the relevant activity.
• In many problems, that means efficient output satisfies:
  • ( MB = MC )
  • and if the market were competitive, the equilibrium could align with this condition.

Step-by-step approach for typical welfare questions

1. Identify the demand curve (MB).
2. Identify marginal cost (MC) from cost information.
3. Find:
   • competitive quantity where (P=MC),
   • monopoly quantity where (MR=MC),
   • then compute welfare areas (surpluses and deadweight loss).

Even if you don’t compute exact numeric areas, you should draw and label:

• consumer surplus,
• producer surplus,
• deadweight loss triangle between efficient and market quantities.

2.2 Externalities: taxes, subsidies, and cap-on harm

If an activity imposes costs or benefits on third parties, market outcomes are typically not efficient.

Negative externality example structure

Let private marginal cost be ( MPC ) and social marginal cost be:

• ( MSC = MPC + MEC ) (marginal external cost)

A tax equal to the marginal external cost can align private incentives:

• ( t = MEC )

Then:

• the firm’s effective marginal cost becomes ( MPC + t = MSC ),
• so equilibrium quantity moves toward the efficient quantity.

Numerical template (how to set up quickly)

Suppose market demand:

• ( P(q)=100 – q \Rightarrow MB(q)=100-q )

Private marginal cost:

• ( MPC(q) = 20 + q )

Marginal external cost:

• ( MEC(q)= 10 ) (constant)

Then:

• ( MSC(q)= 20+q + 10 = 30+q )

Efficient quantity solves:

• ( MB(q)=MSC(q) \Rightarrow 100 – q = 30 + q \Rightarrow 70 = 2q \Rightarrow q^{eff}=35 )

Competitive/uncorrected market (no tax) solves:

• ( MB(q)=MPC(q) \Rightarrow 100-q = 20+q \Rightarrow 80=2q \Rightarrow q^{market}=40 )

So the externality causes overproduction: (q^{market}=40) exceeds (q^{eff}=35).

Tax:

• ( t=MEC=10 )

In a full solution, you would also compute:

• prices under each scenario,
• welfare gain due to correction.

2.3 Positive externalities: subsidies and optimal intervention

For positive externalities (benefits spill over), social marginal benefit exceeds private marginal benefit:

• ( SMB = MPB + MEB )

A subsidy equal to marginal external benefit:

• ( s = MEB )

If a question asks for the difference between a subsidy and a tax, your reasoning should flip:

• Negative: too much production → tax.
• Positive: too little production → subsidy.

2.4 Public goods: free-riding and why markets struggle

A public good is non-excludable and non-rival. The key efficiency issue:

• each individual underestimates social value because they only consider private marginal benefit.

For a public good with two consumers with marginal benefits (MB_1(q)) and (MB_2(q)), the efficient rule is:

• ( MB_{social}(q) = MB_1(q)+MB_2(q) )

Then choose (q) where:

• ( MB_{social}(q)=MC(q) )

Markets often result in too little provision because each consumer benefits from others’ spending without paying full cost.

Exam-friendly example setup

Let:

• ( MB_1(q)=20-q )
• ( MB_2(q)=15-q )
• ( MC(q)=5+q )

Social marginal benefit:

• ( MB_1+MB_2 = (20-q)+(15-q)=35-2q )

Efficient (q):

• ( 35 – 2q = 5 + q \Rightarrow 30 = 3q \Rightarrow q^{eff}=10 )

If each consumer alone would set:

• ( MB_i(q)=MC(q) ) privately, you would get lower contributions. You can emphasize that free-riding is a structural problem.

2.5 Deadweight loss, efficiency, and distribution

Microeconomics II often includes a conceptual component: efficiency vs equity.

A policy that increases efficiency can still be distributionally unfair. Exams may ask:

• “Is the Pareto improvement guaranteed?”
• “What happens to consumer surplus and who gains/loses?”

Key terms:

• Pareto efficient: no one can be made better off without making someone else worse off.
• Kaldor-Hicks: policy could pass if winners could theoretically compensate losers, even if compensation doesn’t occur.

UCT-style answers are usually balanced:

• show direction of welfare change,
• then discuss distribution and feasibility.

2.6 Application: policy instruments—price vs quantity and administrative reality

Sometimes exam questions ask you to compare:

• Pigouvian tax vs cap-and-trade,
• or subsidy vs regulation.

Economic logic:

• If you can precisely target marginal external harm/benefit, a Pigouvian tax can replicate the efficient condition.
• If measurement is difficult, quantity regulation or performance standards may be more feasible, though they may not achieve the same efficiency.

In written answers, you should:

1. State the goal (correct externality).
2. Explain the mechanism (align marginal incentives).
3. Mention key assumption (ability to measure marginal harm/benefit).
4. Conclude with efficiency expectation.

3. Consumer Theory: Utility Maximization, Choice Under Uncertainty, and Risk (with Microeconomics II Techniques)

3.1 Utility maximization and the budget constraint

Consumer theory is often tested more technically in Microeconomics II because you must demonstrate derivations and interpret conditions.

Consumer chooses consumption bundle ( (x,y) ) to maximize utility subject to budget:

• ( p_x x + p_y y = m )

A classic Lagrangian setup:

1. ( \max_{x,y} U(x,y) )
2. s.t. ( p_x x + p_y y = m )

Set up:

• ( \mathcal{L} = U(x,y) + \lambda(m – p_x x – p_y y) )

First-order conditions:

• ( \frac{\partial U}{\partial x} = \lambda p_x )
• ( \frac{\partial U}{\partial y} = \lambda p_y )

Divide:

• ( \frac{MU_x}{MU_y} = \frac{p_x}{p_y} )

This is the “tangency” condition: the consumer equates marginal rate of substitution (MRS) to the price ratio.

3.2 Interior vs corner solutions

Exams sometimes include goods that can be substitutes or perfect complements, leading to corner outcomes.

• Interior solution: tangency and FOCs hold.
• Corner solution: MRS may be outside price ratio due to non-negativity constraints.

Example: perfect complements utility:

• ( U(x,y)=\min{x,y} )

Then consumption follows a fixed proportion. The optimization reduces to choosing how many “units” of the complement bundle you can afford.

3.3 Slutsky decomposition: substitution and income effects

A major Microeconomics II technique involves decomposing the effect of a price change on quantity demanded.

Slutsky decomposition:

• total effect = substitution effect + income effect (via compensating variation)

For a normal good:

• substitution effect and total effect generally go in same direction (price up → quantity down).
• income effect depends on whether the good is normal or inferior.

If asked to interpret a graph:

• you should use the compensated demand curve idea to show substitution effect.

3.4 Revealed preference vs demand derivation (exam interpretive angle)

Although many courses focus on utility functions, UCT exam questions often reward:

• ability to interpret behavior (homothetic preferences, standard demand properties),
• and to state demand monotonicity results.

For example, if utility is homothetic:

• expenditure shares remain constant,
• Engel curves have predictable shapes.

3.5 Choice under uncertainty: expected utility

Uncertainty questions test both computation and reasoning.

Let outcomes (o_1,o_2,\dots) occur with probabilities (p_1,p_2,\dots).
Expected utility:

• ( EU = \sum_i p_i u(o_i) )

Consumer chooses the action with higher expected utility.

Common exam tasks:

• compute (EU) for each option,
• rank lotteries,
• compare to certainty equivalents.

3.6 Example: comparing two risky options

Suppose investor has utility ( u(w)=\sqrt{w} ).

Option A:

• with probability 0.5: wealth (w=100)
• with probability 0.5: wealth (w=25)

Expected utility:

• ( EU_A = 0.5\sqrt{100}+0.5\sqrt{25} = 0.5\cdot 10 + 0.5\cdot 5 = 7.5 )

Certainty equivalent (CE_A) solves:

• ( \sqrt{CE_A} = 7.5 \Rightarrow CE_A = 56.25 )

Option B:

• with probability 0.5: (w=81)
• with probability 0.5: (w=36)

Expected utility:

• ( EU_B = 0.5\cdot 9 + 0.5\cdot 6 = 7.5 )

So (EU_A=EU_B), meaning they are indifferent under expected utility.

You would then interpret:

• different “risk” profiles can be equivalent if expected utility matches.

3.7 Risk premium and risk aversion

Risk premium is the amount a risk-averse person would pay to avoid risk.

If certainty equivalent is (CE) and expected wealth is (E[w]):

• risk premium (RP = E[w]-CE)

In Option A above:

• (E[w]=0.5\cdot 100+0.5\cdot 25=62.5)
• (CE=56.25)
• (RP=6.25)

An exam might ask to state how risk premium changes with:

• increased variance (typically increases for risk-averse agents),
• changes in curvature of utility (more concavity → more risk aversion).

3.8 Risk and diversification: portfolio intuition

If returns are uncertain across independent states, combining risks can reduce variance.

But in expected utility, the key is not only variance; it also depends on how utility maps outcomes.

For small risks, risk effects can be approximated using Taylor expansions:

• second derivative of utility determines sensitivity to risk.

Your qualitative statements should always align with:

• concave utility → risk aversion.

4. Intertemporal Choice and Demand for Time: Present Value, Consumption Smoothing, and Applications

4.1 Intertemporal budget constraint and present value

Intertemporal choice models decisions across time (t=0,1,\dots). A standard setup:

• consumer has initial wealth and income over time,
• interest rate (r),
• chooses consumption (C_0) and (C_1).

Budget constraint example (two-period):

• ( C_0 + \frac{C_1}{1+r} = m )

Equivalently:

• ( C_0 + \frac{C_1}{1+r} = ) present value of resources.

This is tested because students must compute present value properly.

Example: compute affordable consumption bundles

Suppose:

• (m = 100),
• (r=0.10),
• choose (C_0=60).

Then:

• ( 60 + \frac{C_1}{1.10} = 100 \Rightarrow \frac{C_1}{1.10}=40 \Rightarrow C_1=44 )

Show this computation in steps.

4.2 Consumption smoothing: Euler equation intuition

With standard preferences, consumers prefer smooth consumption over time because marginal utility decreases with consumption (diminishing marginal utility).

For utility (U = u(C_0)+\beta u(C_1)), the Euler condition for optimality is:

• ( u'(C_0) = \beta(1+r)u'(C_1) )

An exam might ask you to interpret:

• if (r) increases, saving becomes more attractive,
• the consumer shifts consumption toward the future unless constrained.

4.3 Savings vs borrowing constraints

Some questions include constraints like:

• non-borrowing: (C_1) cannot be financed beyond available resources,
• or limits on negative savings.

These constraints can create corner solutions:

• you consume as much as possible at (t=0),
• or defer consumption in a way that violates unconstrained smoothing.

In your answers:

• explicitly say whether the Euler condition holds (interior) or not (corner).

4.4 Present value and dynamic pricing/policy examples

Microeconomics II often uses present value to connect policy to consumption.

Examples:

• subsidy paid now vs later,
• tax credit at different times,
• discounting of future benefits (like energy-efficiency investments).

When asked which policy is more valuable, compare their present values.

Example: compare two payments

Payment 1: R 1,000 now.
Payment 2: R 1,120 in 1 year.
Discount rate (r=12%).

PV of payment 2:

• ( PV = \frac{1120}{1.12} = 1000 )

So the payments have equal present value.

Be careful: exam problems frequently test whether you invert the discount factor correctly.

4.5 Intertemporal demand curve and substitution effect over time

Price changes are analogous to interest-rate changes in intertemporal choice:

• an increase in (r) changes the relative price of future consumption.
• it also induces income effects if the consumer’s resources depend on returns.

Your decomposition should align:

• substitution: consumer wants relatively cheaper time.
• income: richer or poorer depending on net position.

4.6 Intertemporal choice under uncertainty (short extension)

If income in the future is uncertain, then the consumer may value insurance. In that context:

• expected utility with time and uncertainty can combine risk preferences with discounting.

Even when full modeling is complex, exam questions may ask:

• whether the consumer prefers certain vs risky outcomes for the same expected value.

5. Exam-Style Problem Solving Toolkit: Derivations, Diagrams, and Typical ECO2003F Tasks (UCT-Aligned)

5.1 A method for writing full-mark answers in microeconomics

Microeconomics II exams often reward a structured approach. A disciplined workflow:

1. State the model and assumptions
   • e.g., monopoly with downward-sloping demand, constant MC, no fixed cost; or Cournot with linear demand.
2. Set up the firm/consumer problem
   • maximize profit or utility under constraints.
3. Derive the equilibrium condition
   • e.g., (MR=MC), (P=ATC) in long run monopolistic competition, best response in games.
4. Solve algebraically
   • show intermediate steps and substitutions.
5. Interpret economically
   • inefficiency, market power, welfare triangles, strategic implications.
6. Connect to policy/welfare if asked.

This method is particularly effective for UCT Economics-style marking schemes: examiners look for the condition and the interpretation.

5.2 Diagram “checklist”: what must be labeled

For each common topic, include these essentials:

Externalities diagram labels

• MB (or MPB) curve and MC (MPC) curve
• social marginal cost (MSC) or social marginal benefit (SMB)
• efficient quantity (q^{eff})
• market quantity (q^{market})
• tax amount aligned with (MEC) at efficient (q)
• triangles for deadweight loss

Market structure diagram labels

• monopoly: show (MR), (Demand), (MC), equilibrium (q_m)
• perfect competition: show (D) and (MC) intersection for (q_c)
• welfare comparison: deadweight loss triangle between efficient and monopoly quantities

Game theory diagram equivalent (game tables)

• label best responses
• identify Nash equilibrium cell
• if asked about cooperation, identify Pareto-superior outcome and explain why it’s not stable.

5.3 Standard derivations you must master

(A) Monopoly with linear demand

Demand:

• (P=a-bq)

Revenue:

• (TR = (a-bq)q = aq – bq^2)

Marginal revenue:

• (MR = a – 2bq)

Set MR=MC:

• if (MC=c) constant:
  • (a – 2bq = c \Rightarrow q_m = \frac{a-c}{2b})
  • (P_m = a – bq_m = a – b\frac{a-c}{2b} = \frac{a+c}{2})

This derivation appears constantly in exam questions that ask for:

• monopoly quantity,
• monopoly price,
• profits (if fixed costs absent),
• comparison with competitive.

(B) Cournot with linear demand

As done earlier:

• (q_i = \frac{a-c}{2b} – \frac{1}{2}q_{-i})
• symmetric equilibrium:
  • (q = \frac{a-c}{3b})
  • (Q = \frac{2(a-c)}{3b})
  • (P = a – bQ)

(C) Welfare: deadweight loss (how to compute or explain)

If demand and MC are linear, DWL can often be computed as triangle area:

• (DWL = \frac{1}{2}\cdot (q^{eff}-q^{market}) \cdot (P_{some}-MC_{some}))

If numbers are provided, compute explicitly.
If not, draw and describe the region.

5.4 Worked mini-cases (integrated practice)

Mini-case 1: Compare monopoly vs competitive output and welfare

Assume:

• Demand (P=100-q)
• Constant MC (c=20)

Competitive:

• (P=MC \Rightarrow 100-q = 20 \Rightarrow q_c=80)
• Price (P_c=20)

Monopoly:

• (MR = a – 2bq) with (a=100, b=1): (MR=100-2q)
• Set (100-2q = 20 \Rightarrow 2q=80 \Rightarrow q_m=40)
• Price (P_m = 100-40=60)

Interpretation:

• monopoly produces less: (40 < 80)
• price higher: (60 > 20)
• deadweight loss exists because units between 40 and 80 are valued by consumers above marginal cost but not produced.

If the exam asks for a welfare statement:

• show DWL triangle between efficient and monopoly quantities.

Mini-case 2: Externality correction with a per-unit tax

Suppose:

• Demand (P=50-q) so (MB(q)=50-q)
• Private marginal cost (MPC=q)
• Marginal external cost (MEC=10)

Then:

• (MSC=MPC+MEC=q+10)

Efficient:

• (MB=MSC\Rightarrow 50-q=q+10 \Rightarrow 40 = 2q \Rightarrow q^{eff}=20)

Market without tax:

• (MB=MPC\Rightarrow 50-q=q \Rightarrow 50=2q \Rightarrow q^{market}=25)

Tax:

• (t=10)

Interpretation:

• tax reduces output from 25 to 20 by raising firms’ effective marginal cost.

In an exam, you might also compute:

• consumer and producer surpluses before and after, and show net welfare improvement.

Mini-case 3: Cournot equilibrium with numbers

Let:

• (P=100-(q_1+q_2))
• (c=20)

Then (a=100, b=1).
Each firm:

• (q = \frac{a-c}{3b} = \frac{80}{3})

We already computed:

• (q \approx 26.67)
• (Q \approx 53.33)
• (P \approx 46.67)

Compare with monopoly (previous mini-case):

• monopoly with (a=100,c=20): (q_m=(a-c)/2b=80/2=40) (with linear demand same b=1)
• here Cournot output is (53.33) which exceeds monopoly but is below competitive (q_c=80).

So oligopoly sits between monopoly and competition.

Write this as a clear sentence:

• “Cournot outcome is more competitive than monopoly but less competitive than perfect competition.”

5.5 Common mistakes that cost marks (and how to avoid them)

These appear repeatedly in micro exams:

1. Using MR=MC incorrectly

   • For monopoly and monopolistic competition, MR must come from revenue function. Do not set demand = MC.

2. Confusing private and social costs

   • In externalities, efficient condition uses MSC or SMB, not MPC/MPB.

3. Forgetting economic profit vs accounting profit

   • Long-run monopolistic competition requires zero economic profit, so include ATC and opportunity cost.

4. Game theory: mixing up player i and rival

   • In best responses, use (q_{-i}) carefully and then impose symmetry.

5. Present value algebra errors

   • Always divide by (1+r) to discount future values to present.

6. Not interpreting results

   • Even if the algebra is correct, without a welfare or incentive interpretation, you often lose marks.

5.6 Institution-specific exam culture: leveraging UCT resources effectively

Because this guide targets UCT Economics Study Guides within the broader South African university context, it emphasizes an exam culture you’ll recognize in tutorial questions and past papers:

• Derive, then interpret: most marking schemes reward the equilibrium condition derivation.
• Use diagrams to structure your narrative: even when not explicitly requested, a quick labeled diagram supports reasoning.
• Be explicit about assumptions: constant MC, linear demand, no fixed costs, full information, simultaneous moves—your answer must match the question’s setup.
• Check for plausibility: negative quantities or imaginary outputs usually indicate an algebra mistake.

While course content and paper formats can vary year to year, the underlying logic of Microeconomics II remains stable: micro theory is about incentives, equilibrium, and welfare.

5.7 A final “one-page” checklist for your ECO2003F exam

Use this checklist to guide your last-minute revision:

• Market structure
  • Can I derive MR from demand?
  • Can I compute MR=MC equilibrium?
  • Can I explain long-run monopolistic competition entry and zero economic profit?
  • In Cournot, can I write best response and impose symmetry?
• Welfare
  • Can I state efficient condition (MB=MC or SMB=SMC)?
  • Can I explain deadweight loss direction (over/underproduction)?
  • Can I interpret taxes/subsidies as marginal alignment tools?
• Consumer choice
  • Can I set MRS = price ratio from utility maximization?
  • Can I interpret normal vs inferior goods via income effects?
• Uncertainty
  • Can I compute expected utility and rank lotteries?
  • Can I interpret risk premium and certainty equivalent?
• Intertemporal
  • Can I calculate present value correctly?
  • Can I use Euler intuition (marginal utility conditions) and interpret changes in r?

Concluding synthesis

ECO2003F Microeconomics II is best mastered by treating every problem as a chain: assumptions → equilibrium condition → computation → interpretation → welfare. When you combine rigorous derivations (MR=MC, best responses, expected utility, present value budgets) with careful welfare analysis (efficiency vs inefficiency, deadweight loss, policy instruments), your answers become both correct and exam-markable. Use the mini-cases as templates for your own practice, and always write solutions in the same structured way—so your reasoning stays visible to the marker.