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📐 Mathematics  ·  Linear Programming  ·  JEE

If the feasible region of an LPP is unbounded, what is true about finding the maximum of the objective function?

Answer: A maximum may not exist even if the corner point values suggest one, and must be checked separately.

  • A A maximum tends to exist at a corner point in most cases, regardless of how unbounded the region is
  • B A maximum may not exist even if the corner point values suggest one, and must be checked separately
  • C Maximization becomes considerably harder to define clearly on an unbounded region
  • D The feasible region would first need to be re-drawn artificially as a bounded shape

Correct answer: B. A maximum may not exist even if the corner point values suggest one, and must be checked separately

Explanation: On an unbounded feasible region, a value that looks like the maximum from corner points must be verified by checking whether the half-plane Z > that value has any point in common with the feasible region; if it does, no maximum exists.

Feasible Region and Corner PointsxyOABCfeasible regionZ = ax+by is evaluated ONLY at corners O, A, B, C - the optimum is always at one of these

The feasible region (shaded) is bounded by the constraint lines; the fundamental theorem of LPP guarantees the optimal value of the objective function occurs at one of the corner points (O, A, B, C), so only these need to be checked, not the entire region.

Concept context

Optimizing a linear objective function subject to linear constraints using the graphical corner point method.

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