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MHT CET · Maths · Application of Derivatives

If \(f(x)=k x-\sin x\) is monotonically increasing, then

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

Answer & Solution

Correct Answer

(A) \(k>1\)

Step-by-step Solution

Detailed explanation

Since, \(f(x)=k x-\sin x\) is monotonically increasing for all \(x \in R\). Therefore,
\(
f^{\prime}(x)>0 \text { for all } x \in R
\)
\(\therefore \quad f^{\prime}(0)>0\)
\(\Rightarrow k-\cos 0>0\)
\(\Rightarrow k > 1\)