Microeconomics and macroeconomics tutoring in English
An economics tutor for students on English-taught business programmes in Spain, covering both microeconomics and macroeconomics. One to one, online, and at whatever hour works for you, including the week before the exam.
Economics rewards a particular habit: reading the graph before reaching for the algebra. Most exam questions can be half-answered from a well-drawn diagram, and the calculation then just confirms what the picture already told you. That is the habit we build.
Consumer theory and demand
Preferences, indifference curves and the budget constraint, then the optimum where the marginal rate of substitution equals the price ratio. From there we derive the demand curve, and separate a price change into its substitution and income effects. We cover elasticity properly, price, income and cross elasticity, because the sign and the magnitude both carry meaning and exam questions test whether you can interpret them rather than just compute them.
Production, costs and the supply side
The production function, marginal and average product, and why diminishing returns show up in the shape of the cost curves. Fixed, variable, total, average and marginal cost, and the relationships between them, in particular why marginal cost cuts average cost at its minimum. Then the distinction between the short run and the long run, returns to scale, and the shutdown decision, which is the classic question about when a loss-making firm should still keep producing.
Market structures, from perfect competition to oligopoly
Perfect competition and the zero economic profit result in the long run. Monopoly, where price is set above marginal cost and the Lerner index measures by how much, along with deadweight loss and price discrimination. Then the awkward middle: monopolistic competition, and oligopoly with Cournot, Bertrand and Stackelberg, plus the game theory basics you need for the Nash equilibrium questions that always appear.
National accounts and aggregate demand
The macro half starts with measurement: what GDP includes and excludes, nominal against real, the deflator against the consumer price index, and the three equivalent ways of computing it. Then the components of aggregate demand, the consumption function, the multiplier, and why the multiplier is smaller once you allow for taxes and imports. Getting the accounting identities right here saves you throughout the rest of the module.
The IS-LM model and policy
Building the IS curve from goods market equilibrium and the LM curve from money market equilibrium, then reading the two together. What shifts each curve, how fiscal and monetary policy work through them, and crowding out. We extend into aggregate supply and demand, look at the short-run and long-run outcomes, and cover inflation, unemployment and the Phillips curve, plus the open economy version if your syllabus goes there.
How the lessons work
Video call, one to one, with a whiteboard where we draw every diagram from scratch rather than pasting a finished one. No fixed timetable, no packages. Send me your lecturer's slides and past papers and we work in that framework, because economics notation varies a lot between courses and the exam expects the version you were taught.
Where almost everyone gets stuck
Confusing a movement along a curve with a shift of it
A change in the good's own price moves you along the demand curve. A change in income, tastes or the price of a related good shifts the whole curve. Getting this backwards turns a correct explanation into a wrong one, and it is examined in almost every paper because it reveals whether the model is actually understood.
Setting price equal to marginal cost for a monopolist
Every firm maximises profit where marginal revenue equals marginal cost. Under perfect competition price equals marginal revenue, so the shortcut works. A monopolist faces a downward-sloping demand curve, so marginal revenue is below price and the two are not interchangeable. Find the quantity from MR = MC, then read the price off the demand curve.
Treating fixed costs as if they mattered to the output decision
Fixed costs affect whether the firm is profitable, not how much it should produce. The output decision compares marginal revenue with marginal cost, and fixed costs appear in neither. They come back in when you ask whether to shut down in the long run, which is a different question.
Worked example: monopoly with linear demand, price, quantity, profit and Lerner
A monopolist faces the inverse demand function P = 100 - 2Q and has a total cost function TC(Q) = 20Q + 100. Find the profit-maximising quantity and price, the profit obtained and the Lerner index. Also work out what quantity would be produced under perfect competition.
- Total revenue: TR = P x Q = (100 - 2Q) x Q = 100Q - 2Q^2. Differentiating with respect to Q, marginal revenue is MR = 100 - 4Q.
- Marginal cost: differentiating TC = 20Q + 100 gives MC = 20, a constant. The fixed cost of 100 does not affect the output decision, only the final profit.
- Profit-maximising condition: MR = MC, so 100 - 4Q = 20, giving 4Q = 80 and Q = 20 units. Substituting into the demand function: P = 100 - 2 x 20 = 60 euros.
- Profit: TR = 60 x 20 = 1,200 euros; TC = 20 x 20 + 100 = 500 euros. Profit = 1,200 - 500 = 700 euros.
- Lerner index: L = (P - MC)/P = (60 - 20)/60 = 0.667. It is consistent with 1/|Ed|, because at that point |Ed| = (1/2) x (60/20) = 1.5 and 1/1.5 = 0.667. Under perfect competition output would be where P = MC: 100 - 2Q = 20, so Q = 40 units.
SolutionQ = 20 units, P = 60 euros, profit = 700 euros and a Lerner index of 0.667. The perfectly competitive quantity would be Q = 40 units, double the monopoly output.
About these lessons in particular
Do you cover both micro and macro, or do I have to choose?
Both, and often in the same session if you have the two modules running at once. Tell me which topics are coming up and we plan around your exam dates.
My course uses different notation from the textbook. Does that matter?
It matters a lot, and it is the main reason I ask for your lecturer's slides before we start. We use the notation your exam uses, not a generic version.
Can we do this in English?
Yes, the entire module. I live and study in the United States, so English is where I work daily, and we can switch to Spanish for anything that is clearer that way.
I also teach
Shall we work on it together?
Tell me where you are, which university you are at and when the exam is. I will get back to you as soon as I can.