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CUET · MATHS · PYQ PAPER 2023

The maximum value of \(\left( \frac{1}{x} \right)^x\) is :

  1. A \(e\)
  2. B \(e^e\)
  3. C \(\frac{1}{e}\)
  4. D \(\left( \frac{1}{e} \right)^{\frac{1}{e}}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\left( \frac{1}{e} \right)^{\frac{1}{e}}\)

Step-by-step Solution

Detailed explanation

Let \(f(x) = \left( \frac{1}{x} \right)^x = x^{-x}\). Take \(\ln f(x)\): \(\ln f(x) = -x \ln x\). Differentiate: \(\frac{f'(x)}{f(x)} = -(\ln x + 1)\). Set \(f'(x) = 0 \implies -(\ln x + 1) = 0\). \(\ln x = -1 \implies x = e^{-1} = \frac{1}{e}\). Maximum value:…