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CUET · MATHS · PYQ PAPER 2025

If the interval in which \(f(x)=\frac{x}{4}+\frac{4}{x}, x \neq 0\) is strictly increasing is \((-\infty, a) \cup(b, \infty)\), then

  1. A \(a=b\)
  2. B \(a=-b\)
  3. C \(a=2 b\)
  4. D \(a=-2 b\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(a=-b\)

Step-by-step Solution

Detailed explanation

\(f'(x) = \frac{1}{4} - \frac{4}{x^2}\) \(\frac{1}{4} - \frac{4}{x^2} > 0 \implies x^2 > 16\) \((x-4)(x+4) > 0 \implies x \in (-\infty, -4) \cup (4, \infty)\) \(a = -4, b = 4\) \(a = -b\)