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NCERT Solutions for Class 12 Mathematics Chapter 12 Linear Programming

NCERT Solutions for Class 12 Mathematics Chapter 12 Linear Programming covers the formulation of linear programming problems, the graphical method of solving them, and the concept of the feasible region and optimal solutions occurring at corner points.

Overview of Topics & Subtopics (Click to Jump)

1. Formulating a Linear Programming Problem

Short Note:

• A linear programming problem (LPP) involves an objective function (a linear function to be maximized or minimized) subject to a set of linear constraints, usually expressed as inequalities.

• Decision variables in an LPP typically represent quantities to be determined and are restricted to non-negative values, reflecting real-world limitations like production quantities or resource usage.

2. Graphical Method and Feasible Region

Short Note:

• For problems involving two variables, each constraint is plotted as a line on a graph, and the feasible region is the common region satisfying all constraints simultaneously.

• The feasible region can be bounded (enclosed within a finite area) or unbounded (extending infinitely in some direction), which affects whether a maximum or minimum value definitely exists.

3. Corner Point Method

Short Note:

• According to the fundamental theorem of linear programming, the optimal value of the objective function occurs at one of the corner points (vertices) of the feasible region.

• The corner point method involves evaluating the objective function at each vertex of the feasible region and comparing the results to identify the maximum or minimum value.

NCERT Textbook Exercise Questions

What are the essential components of a linear programming problem?
Answer: A linear programming problem consists of an objective function, which is the linear expression to be maximized or minimized (such as profit or cost), and a set of linear constraints expressed as inequalities that restrict the possible values of the decision variables. Additionally, the decision variables themselves are typically required to satisfy non-negativity restrictions, since most real-world quantities cannot be negative.
Explain the graphical method for solving a linear programming problem with two variables.
Answer: Each linear constraint is first plotted as a straight line on a graph, and the appropriate half-plane satisfying the inequality is shaded to represent that constraint. The region common to all shaded half-planes, known as the feasible region, contains every point that satisfies all constraints simultaneously, and its corner points are then evaluated to find the optimal solution.
State the corner point method used to find the optimal solution of an LPP.
Answer: According to the corner point method, the objective function is evaluated at each vertex (corner point) of the feasible region, and the largest of these values gives the maximum, while the smallest gives the minimum. This method is based on the fundamental theorem of linear programming, which guarantees that the optimal solution, if it exists, will occur at one of these corner points.
What is the difference between a bounded and an unbounded feasible region in a linear programming problem?
Answer: A bounded feasible region can be enclosed within a circle of finite radius, meaning it does not extend infinitely in any direction; in such regions, both a maximum and minimum value of the objective function are guaranteed to exist. An unbounded feasible region, on the other hand, extends infinitely in at least one direction, and in this case, a finite optimal value may or may not exist, requiring further verification.
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Class 12 › Mathematics › Linear Programming
Chapter notesRead the chapterPractice MCQsCheck what you rememberChapter test10 questions on one pageOnline testTest 1, 2 and 3, one question at a timePYQPrevious year questionsStudy materialPDF notes
Topics in this chapter: Formulating a Linear Programming ProblemGraphical Method and Feasible RegionCorner Point Method