The value of ' \(k\) ' for which the function \(f(x)=k(x+\sin x)+k\) is increasing, is equal to

The value of ' \(k\) ' for which the function \(f(x)=k(x+\sin x)+k\) is increasing, is equal to
  1. \(k < 0\)
  2. \(k>0\)
  3. \(k=0\)
  4. Data Insufficient

Solution

Given function \(f(x)=k(x+\sin x)+k\) So, \(\quad f^{\prime}(x)=k(1+\cos x)\) \(\because f(x)\) is an increasing function, so \(\begin{aligned} & f^{\prime}(x) \geq 0 \\ & \Rightarrow \quad k(1+\cos x) \geq 0 \\ & \Rightarrow \quad k > 0 \quad\{\because 1+\cos x \geq 0\} \\ \end{aligned}\)

Asked in: AP EAMCET 2020 (18 Sep Shift 1)

Practice more Applications of Derivatives questions on Aicharya