A value of $x$ for which $\sin \left( \cot ^ { - 1 } ( 1 + x ) \right) = \cos \left( \tan ^ { - 1 } x \right)$, is :\\ (1) $- \frac { 1 } { 2 }$\\ (2) 1\\ (3) 0\\ (4) $\frac { 1 } { 2 }$