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Questions › DSE › DSE 2021 › Q1
4 marks, −1Mathematics › Constrained optimisation and linear programming › Inequality constraints, second-order conditions and envelope theoremModerateabout 3 min

DSE 2021 Question 1: Constrained optimisation and linear programming

Consider the problem of maximizing f(x,y)=x2+2xy+by2f(x,y) = x^2 + 2xy + by^2f(x,y)=x2+2xy+by2 with respect to x,yx, yx,y subject to the constraint x+y=100x + y = 100x+y=100, where bbb is a parameter taking some fixed value greater than 111. Let v(b)v(b)v(b) be the value attained, as a function of bbb, and let v′(b)v'(b)v′(b) be its derivative. Which of the following is correct?

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Consider the problem of maximizing f(x,y) = x² + 2xy + by² with respect to x, y subject to the constraint x + y = 100, where b is a parameter taking some fixed value greater than 1. Let v(b) be the value attained, as a function of b, and let v′(b) be its derivative. Which of the following is correct? (A) v′(b) > 0 (B) v′(b) < 0 (C) v′(b) = 0 (D) The sign of v′(b) changes with b

Also written as: Consider the problem of maximizing f(x,y) = x^2 + 2xy + by^2 with respect to x, y subject to the constraint x + y = 100, where b is a parameter taking some fixed value greater than 1. Let v(b) be the value attained, as a function of b, and let v'(b) be its derivative. Which of the following is correct?

Constrained optimisation and linear programming has come up 44 times in 7 exams since 2007.

What this question tests

This question is on Inequality constraints, second-order conditions and envelope theorem, part of Constrained optimisation and linear programming in Mathematics.

Optima with inequality constraints, tests for maxima, and how the optimal value changes with parameters.

TestStop has 8 past-paper questions on this subtopic; the nearest in year are below.

  • IIT JAM 2021 · Q55The optimal value of: minimize 2xy subject to 9x² + 4y² ≤ 36 is _ (in integer).
Practise Constrained optimisation and linear programmingMore on Inequality constraints, second-order conditions and envelope theorem

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