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CUET · MATHS · PYQ PAPER 2025

In which of the following interval the function \(f(x)=x^x, x>0\) is strictly increasing?

  1. A \([e, \infty)\)
  2. B \(\left(\frac{1}{e}, \infty\right)\)
  3. C \([1, \infty)\)
  4. D \([0, \infty)\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\left(\frac{1}{e}, \infty\right)\)

Step-by-step Solution

Detailed explanation

Let \(y = x^x\). \(\ln y = x \ln x\) \(\frac{1}{y}\frac{dy}{dx} = \ln x + 1\) \(f'(x) = x^x(\ln x + 1)\) For strictly increasing, \(f'(x) > 0\). \(x^x(\ln x + 1) > 0\) Since \(x > 0\), \(x^x > 0\). So, \(\ln x + 1 > 0\) \(\ln x > -1\) \(x > e^{-1}\) \(x > \frac{1}{e}\) Interval:…
From CUET
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