A function is a quasi-convex function if and only if
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2 marks, −0.666666666666667MathematicsConcavity, convexity and quasi-concavityQuasi-concavity and quasi-convexityModerateabout 3 min
DSE 2017 Question 20: Concavity, convexity and quasi-concavity
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A function f:ℝⁿ→ℝ is a quasi-convex function if and only if (A) {(x,y)∈ℝⁿ×ℝ| y≥ f(x)} is a convex set (B) {x∈ℝⁿ| y≥ f(x)} is a convex set for every y∈ℝ (C) {(x,y)∈ℝⁿ×ℝ| y≤ f(x)} is a convex set (D) {x∈ℝⁿ| y≤ f(x)} is a convex set for every y∈ℝ
Also written as: A function f:R^n->R is a quasi-convex function if and only if
Concavity, convexity and quasi-concavity has come up 39 times in 6 exams since 2006.
What this question tests
This question is on Quasi-concavity and quasi-convexity, part of Concavity, convexity and quasi-concavity in Mathematics.
The weaker shape conditions defined by upper or lower level sets.
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Question from the DSE 2017 paper. Solutions are TestStop's own. Not affiliated with or endorsed by any examination authority.