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CUET · MATHS · PYQ PAPER 2025

The real valued function \(f(x)=x^{15}+5 x^9+10\) is increasing for __________ .

  1. A all positive real values of x
  2. B all negative real values of x
  3. C all non-positive real values of x
  4. D all real values of x
Verified Solution

Answer & Solution

Correct Answer

(D) all real values of x

Step-by-step Solution

Detailed explanation

\(f'(x) = \frac{d}{dx}(x^{15}+5 x^9+10) = 15x^{14}+45x^8\) \(f'(x) = 15x^8(x^6+3)\) Since \(x^6 \ge 0\), \(x^6+3 > 0\). Since \(x^8 \ge 0\), \(15x^8 \ge 0\). Thus, \(f'(x) \ge 0\) for all real values of x, and \(f'(x)=0\) only at \(x=0\). The function is increasing for all real…