Q75 / 150 · MHT CET 2021 (23 Sep Shift 1) · Mathematics
$\int \cos ^3 x \cdot e^{\log (\sin x)} d x=$
- A$\frac{-e^{\sin x}}{4}+c$
- Correct answerB$\frac{-\cos ^4 x}{4}+c$
- C$\frac{-\sin ^4 x}{4}+c$
- D$\frac{-e^{\sin x}}{4}+c$
Solution
Let
$$
\begin{aligned}
I & =\int \cos ^3 x \cdot e^{\log (\sin x)} d x \\
& =\int \cos ^3 x \cdot \sin x d x
\end{aligned}
$$
Put $\cos \mathrm{x}=\mathrm{t}$
$$
\therefore I=\int-t^3 d t=\frac{-t^4}{4}+t=\frac{-\cos ^4 x}{4}+c
$$
Hence, the correct answer is option: 'B'.