Gains from Trade: A Numerical Example


1. A closed Economy's problem


PPF: y12 + 4 y22 = KL, MRT = y1/4y2.

 

Utility: U = x1x2, MRS = x2/x1

 

Constraint: x1 = y1, x2 = y2.


2. An Open Economy's Problem


K = 80, L = 10,

p*1 = p*2 = 1.

Step 1: Choose y1 and y2 to Maximize GDP

Step 2

Choose x1 and x2 to maximize U(x1,x2)

 

Prices: p*1 = p*2 = 1.

Budget Constraint: p*1x1 + p*2x2 = Io(income from step 1).


Homework 2


Production possibility frontiers, MRT, utility function, MRS,

resource supplies and international prices are as follows:

PPF: y12 + 4 y22 = KL, MRT = y1/4y2.

Utility: U = x1x2, MRS = x2/x1

K = 18, L = 100,

Prices: p*1 = p*2 = 2. 


A. The autarky problem:
Find y1, y2, UA, (p1/p2)A in autarky.

B. Optimal production under free trade:
Given international prices, p*1, p*2, find optimal output, y1, y2, and Io (maximized income) evaluated at world prices.

F. Optimal consumption under free trade:
Find, x1, x2, UF, z1 (export) and z2 (import).

G. Evaluate the gains from trade, G = UF - UA.

S. Sketch the solutions and carefully label points A, B, and F.

This concludes the math portion of the course.