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CUET · MATHS · PYQ PAPER 2023

If the function \(f(x)=x^2+k x+7\) is strictly increasing in the interval [-2, 2], then

  1. A \(K<4\)
  2. B \(K>4\)
  3. C \(K<-4\)
  4. D \(K>-4\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(K>4\)

Step-by-step Solution

Detailed explanation

\(f(x)=x^2+k x+7\) \(f'(x)=2x+k\) For \(f(x)\) to be strictly increasing in \([-2, 2]\), \(f'(x) > 0\) for all \(x \in [-2, 2]\). The minimum value of \(f'(x)\) in \([-2, 2]\) occurs at \(x=-2\). \(f'(-2) > 0\) \(2(-2)+k > 0\) \(-4+k > 0\) \(k > 4\)