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GATE 2023 ES – Question 7

General Aptitude · Quantitative Aptitude: Algebra, Geometry and Mensuration · 2 marks · Multiple choice

Which one of the following options represents the given graph?

Diagram for GATE 2023 ES question 7
  1. $f(x) = x^2\, 2^{-|x|}$
  2. $f(x) = x\, 2^{-|x|}$
  3. $f(x) = |x|\, 2^{-x}$
  4. $f(x) = x\, 2^{-x}$

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Show answer and explanation

Correct answer: (B) $f(x) = x\, 2^{-|x|}$

Explanation

The curve is an odd function: $f(-x) = -f(x)$, and it tends to 0 for large $|x|$. $x\,2^{-|x|}$ satisfies both. $x^2 2^{-|x|}$ and $|x| 2^{-x}$ are not odd (the first is even and positive), and $x\,2^{-x}$ grows without bound for negative $x$.

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