MCQ
Evaluate: $\int[\sin (\log x)+\cos (\log x)] d x$
  • $x \sin (\log x)+C$
  • B
    $\sin (\log x)+C$
  • C
    $x \cos (\log x)+C$
  • D
    $\cos (\log x)+C$

Answer

Correct option: A.
$x \sin (\log x)+C$
(a) : Let $I=\int[\sin (\log x)+\cos (\log x)] d x$
Put $\log x=t \Rightarrow x=e^t \quad \Rightarrow d x=e^t d t$
$
\begin{aligned}
\therefore \quad I & =\int(\sin t+\cos t) e^t d t=e^t \sin t+C \\
& =x \sin (\log x)+C\left[\because\left[f(x)+f^{\prime}(x)\right] e^x d x=e^x f(x)+C\right)
\end{aligned}
$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free