Math Problem Statement

3.1) Complete each inequality by writing >= or <= in the boxes below. A. y ___ -2 B. y ___ x + 3 C. y ___ -2x + 6 3.2) Is there a maximum of the objective function F = -3x + 2y? If there is, state the coordinate pair where it occurs. If there is not a maximum, explain why. 3.3) Is there a minimum of the objective function F = -3x + 2y? If there is, state the coordinate pair where it occurs. If there is not a minimum, explain why. 3.4) Find an objection function for which the vertex (1,4) is a minimum. Show three calculations to demonstrate the point has a minimum value.

Solution

Let's walk through the questions presented in the image.

3.1 (9 pts) Completing the Inequalities

We are asked to complete the inequalities for three lines (A, B, and C) based on the graph and the feasible region.

  • Line A: The equation is y=2y = -2, which is a horizontal line. The feasible region is above this line, so the inequality should be: y2y \geq -2

  • Line B: The equation of the line is y=x+3y = x + 3. The feasible region lies below the line, so the inequality should be: yx+3y \leq x + 3

  • Line C: The equation is y=2x+6y = -2x + 6. The feasible region lies below this line, so the inequality should be: y2x+6y \leq -2x + 6

3.2 (8 pts) Maximum of the Objective Function

The objective function is F=3x+2yF = -3x + 2y. To check if there's a maximum, we need to evaluate FF at the vertices of the feasible region (since linear programming problems have their extrema at the vertices of the feasible region).

The vertices of the feasible region are:

  • (1,2)(-1, 2)
  • (4,2)(4, 2)
  • (4,2)(4, -2)

Now, we'll compute FF at each vertex:

  • At (1,2)(-1, 2): F=3(1)+2(2)=3+4=7F = -3(-1) + 2(2) = 3 + 4 = 7

  • At (4,2)(4, 2): F=3(4)+2(2)=12+4=8F = -3(4) + 2(2) = -12 + 4 = -8

  • At (4,2)(4, -2): F=3(4)+2(2)=124=16F = -3(4) + 2(-2) = -12 - 4 = -16

The maximum value of FF occurs at (1,2)(-1, 2) with F=7F = 7.

3.3 (8 pts) Minimum of the Objective Function

We already calculated FF at the vertices of the feasible region. The minimum value is 16-16, which occurs at (4,2)(4, -2).

3.4 (8 pts) Objection Function for Minimum at (1, 4)

We need to find an objective function for which the vertex (1,4)(1, 4) is the minimum. One approach is to choose a linear function that decreases in the direction of this point relative to the other vertices of the feasible region.

An example of such a function could be: F=2x+yF = 2x + y

To confirm, we calculate FF at the relevant vertices (including (1,4)(1, 4)) and show that (1,4)(1, 4) gives the smallest value:

  • At (1,4)(1, 4): F=2(1)+4=2+4=6F = 2(1) + 4 = 2 + 4 = 6

  • At another vertex (to compare), for instance (0,2)(0, 2): F=2(0)+2=0+2=2F = 2(0) + 2 = 0 + 2 = 2

This approach shows how you can create an objective function to minimize at (1,4)(1, 4).


Do you want more details or have any questions on these problems? Here are 5 related questions to further explore:

  1. How do you graph linear inequalities and identify feasible regions?
  2. What methods are used to find maximum and minimum values in linear programming?
  3. Can you explain why linear programming solutions always occur at the vertices of the feasible region?
  4. How would the problem change if the objective function was different?
  5. How can we test if a solution is optimal in linear programming?

Tip: Always evaluate the objective function at all vertices of the feasible region to find maximum or minimum values in linear programming problems.

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Math Problem Analysis

Mathematical Concepts

Linear Inequalities
Objective Functions
Linear Programming

Formulas

F = -3x + 2y
Equations of lines: y = -2, y = x + 3, y = -2x + 6

Theorems

Linear Programming Theorem: The maximum or minimum value of a linear objective function occurs at a vertex of the feasible region.

Suitable Grade Level

Grades 10-12