Let $g(x) = f(x) + f(1 - x)$ and $f ^ { \prime \prime } (x) > 0 , x \in (0,1)$. If $g$ is decreasing in the interval $(0 , \alpha)$ and increasing in the interval $(\alpha , 1)$, then $\tan ^ { - 1 } (2\alpha) + \tan ^ { - 1 } \left( \frac { 1 } { \alpha } \right) + \tan ^ { - 1 } \left( \frac { \alpha + 1 } { \alpha } \right)$ is equal to\\
(1) $\pi$\\
(2) $\frac { 5\pi } { 4 }$\\
(3) $\frac { 3\pi } { 4 }$\\
(4) $\frac { 3\pi } { 2 }$