Math Problem Statement

Consider the simplex tableau given below. x 1 x 2 s 1 s 2 s 3 P 2 1 3 0 0 0 4 1 0 4 1 0 0 10 0 0 3 0 1 0 4 negative 6 0 negative 3 0 0 1 2 Question content area bottom Part 1 ​(A) The pivot element is located in column    1 and row    1. Part 2 ​(B) The entering variable is    x 1. Part 3 ​(C) The exiting variable is    s 1

Solution

Let's analyze the given simplex tableau and determine the answers to the questions:

Simplex Tableau Structure:

x₁x₂s₁s₂s₃P
Row 1213000
Row 2410410
Row 30100030
Row 40104-60
Row 50-30012

Part 1 (A): The Pivot Element

To identify the pivot element, we must:

  1. Find the entering variable by locating the most negative number in the objective row (row 5), which corresponds to the coefficient of the non-basic variables in the objective function. The most negative value is -3, which corresponds to x₂.

  2. Find the exiting variable by applying the minimum ratio test to identify which basic variable will leave the basis. We calculate the ratio of the right-hand side (RHS) to the corresponding column element for each row where the column element is positive.

    • For Row 1: 01=0\frac{0}{1} = 0
    • For Row 2: 01=0\frac{0}{1} = 0
    • For Row 3: 010=0\frac{0}{10} = 0
    • For Row 4: 01=0\frac{0}{1} = 0
    • For Row 5: 21=2\frac{2}{1} = 2

    Based on the minimum ratio, the row with x₂ as the entering variable has s₁ as the exiting variable.

Answer for Part 1 (A):

  • The pivot element is located in column 2 and row 1.

Part 2 (B): The Entering Variable

As per the simplex method:

  • The entering variable is the variable corresponding to the most negative number in the objective row, which in this case is x₂.

Answer for Part 2 (B):

  • The entering variable is x₂.

Part 3 (C): The Exiting Variable

As explained in Part 1, the exiting variable corresponds to the basic variable in the row where the ratio test gives the smallest value.

  • In this case, s₁ is the exiting variable based on the minimum ratio test.

Answer for Part 3 (C):

  • The exiting variable is s₁.

Would you like to explore the simplex method further with a step-by-step explanation of how to update the tableau after the pivoting process? Let me know if you'd like to dive deeper into any part!

Additional Questions for Exploration:

  1. How do you perform a pivot operation in the simplex tableau?
  2. What does it mean for a variable to enter or exit the basis in the context of linear programming?
  3. How do you perform the ratio test in simplex?
  4. Can a simplex tableau have more than one negative coefficient in the objective row?
  5. What does it mean if there are no negative coefficients in the objective row?

Tip: Always check the entire objective row for the most negative value when determining the entering variable, and then use the minimum ratio test to determine which basic variable should exit!

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Math Problem Analysis

Mathematical Concepts

Linear Programming
Simplex Method
Optimization

Formulas

Pivot Element Selection
Entering and Exiting Variable Selection
Ratio Test for Basic Variable Selection

Theorems

Simplex Algorithm
Fundamental Theorem of Linear Programming

Suitable Grade Level

Undergraduate (Operations Research, Linear Algebra)