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GATE 2022 BM – Question 26

Engineering Mathematics · Calculus · 1 mark · Multiple select

For real x, select all even functions, on their stated natural domains.

  1. $x|x|$
  2. $\cos x/x$
  3. $\sin(x^2)$
  4. $e^{-|x|}$

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Show answer and explanation

Correct answer: (C) $\sin(x^2)$; (D) $e^{-|x|}$

Explanation

Replacing x by −x leaves x² and |x| unchanged, so sin(x²) and exp(−|x|) are even, C and D. The product x|x| changes sign. Cosine is even but division by x makes cos(x)/x odd on its domain excluding zero. Thus A and B are not even.

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