$\int e^{x \operatorname{cosec} x} \cdot \operatorname{cosec} x \cdot(1-x \cot x) d x=$
$\int e^{x \operatorname{cosec} x} \cdot \operatorname{cosec} x \cdot(1-x \cot x) d x=$
- $e^{x \cot x}+c$
- $e^{x \operatorname{cosec} x}+c$
- $e^{-x \operatorname{cosec} x}+c$
- $e^{-x \cot x}+c$
Solution
$\int e^{x \operatorname{cosec}} x \operatorname{cosec} x(1-x \cot x) d x$
Put, $x \operatorname{cosec} x=t$
Differentiate w.r.to ' $x$ '
$
\begin{aligned}
& x \cdot \frac{d}{d x} \operatorname{cosec} x+\operatorname{cosec} x \cdot \frac{d}{d x} \cdot x=\frac{d}{d x} t \\
& x(-\operatorname{cosec} x \cdot \cot x)+\operatorname{cosec} x(1)=\frac{d t}{d x} \\
& \operatorname{cosec} x(1-x \cot x) d x=d t=\int e^t \cdot d t \\
&=e^t+c=e^{x \operatorname{cosec} x}+c
\end{aligned}
$
Hence, option (2) is correct
Asked in: AP EAMCET 2020 (22 Sep Shift 2)
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