# DEPARTMENT OF ECONOMICS ECON 2750A Spring 2009 ```DEPARTMENT OF ECONOMICS
ECON 2750A
Spring 2009
H.W. #1
Prof. K.C. Tran
Due Date:
Wednesday, January 28, 2009
1. Suppose that the universal set is the set of strictly positive integers, Z  and let
X  {w  Z  : w  15}
W  {w  X : w  12 and w / 2  Z  }
H  {w  X : 5  w  14 and w / 2  Z  }
What are W  H , W  H , W  H , W  H , W  H ?
2. Find the equilibrium solution for each of the following models (please provide explicit
steps for solving each problem and DO NOT use the general solution given in class. Use
(a) QD  3  P 2
Qs  6 P  4
(b) QD  30  2P
Qs  5 P  6
Q D  QS
Q D  QS
3. The demand and supply functions of a two-commodity market model are as follows:
QD1  18  3P1  P2
QD2  12  P1  2 P2
QS1  2  4 P1
QS2  2  3P2
Find the equilibrium prices and quantities for each market.
4. Given u T  5 1 3, v T  3 1  1, and wT  7 5 8 . Write out the column
vectors, u, v and w. Also find (a) uv T ; (b) w T u and (c) v T w .
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