(b)
We know, $\int_{}^{}{e^{x}\lbrack f(x) + f^{'}(x)\rbrack dx} = e^{x}f(x) + c$
$\therefore$ If $f(x) = \log{\sin x}$
$\Rightarrow \ f^{'}(x) = \frac{1}{\sin x}.\cos x = \cot x$
$\therefore\ \int_{}^{}e^{x}\left( \log{\sin x} + \cot x \right)dx = e^{x}\log{\sin x + c}$