Linear Optimization (1:640:354:05)
Spring 1999, Professor Ben-Israel
Assignment 1: LP Formulation and Rn Geometry
Date: Thursday, January 21
Due: Tuesday, February 2
This assignment has four problems, of equal weight. For each of the first three
problems, write an algebraic linear program as we did in class.
Use the "standard" format, starting with clear definitions of the decision
variables as quantities. For example, write "x1
= number of regular widgets to produce," not "x1 = regular".
Once you have defined
variables, write the problem in the form:
Minimize
or
Maximize |
Objective Function |
| Subject To |
Constraint 1 |
|
Constraint 2 |
|
etc. |
Customarily, the constraints involving more than one decision variable
are listed first, followed by the simpler constraints like "x1
> 0"
1 Text, p. 57, Exercise 2.
2 Text, p. 57, Exercise 4.
3 Text, p. 57, Exercise 6.
4 This problem has three parts.
- In R2 consider:
-
the square of side 2 centered at the origin,
i.e. the square with four vertices (-1,-1), (-1,1), (1,-1) and (1,1),
- four circles of radius 1/2 inscribed in the corners of the square (i.e.
circles of radius 1/2 centered at (-1/2,-1/2), (-1/2,1/2), (1/2,-1/2)
and (1/2,1/2)), and
- the smallest circle, with center at the origin, that is tangent to the
above four circles.
Calculate the radius of the inner circle.
- Repeat for R3. Now we have a cube of side 2,
with 8 vertices, 8 balls of radius 1/2 at the 8 corners of the cube
and an inner ball tangent to them.
Calculate the radius of the inner ball.
- Repeat for Rn, for n > 3. Conclude that the
inner ball will eventually stick out of the cube. What is the smallest n for
which this will happen?
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