(a)
We have , $\int_{0}^{2\pi}{(\sin{x + |\sin{x|\ )dx}}}$
$= \int_{0}^{\pi}{(\sin{x + \sin{x)dx + \int_{\pi}^{2\pi}{(\sin{x - \sin{x)\ \ dx}}}}}}$
$= \int_{0}^{\pi}{2\sin{x\ dx + 0 = 2\lbrack - \cos{x\left. \ \ \right\rbrack_{0}^{\pi}}}}$
$= - 2(\cos{\pi - \cos{0) = 4}}$