(a)
$\int_{- 1}^{1}{\lbrack x\lbrack 1 + \sin{\pi x\rbrack + 1\rbrack dx}}$
$= \int_{- 1}^{0}{\lbrack x\lbrack 1 + \sin{\pi x\rbrack + 1\rbrack dx + \int_{0}^{1}{\lbrack x\lbrack 1 + \sin{\pi x\rbrack + 1\rbrack dx}}}}$
Now, $- 1 < x < 0\ \ \Rightarrow \ \lbrack 1 + \sin{\pi x\rbrack = 0}$
$0 < x < 1\ \ \Rightarrow \ \lbrack 1 + \sin{\pi x\rbrack = 1}$
$\Rightarrow \ \lbrack x\lbrack 1 + \sin{\pi x\rbrack + 1\rbrack = 1}$
$\therefore\ \int_{- 1}^{1}{\lbrack x\lbrack 1 + \sin{\pi x\rbrack + 1\rbrack dx = 2}}$