\[\begin{array}{l}
\sin \frac{{\sqrt {1 + x} }}{{\sqrt {1 - x} }}\\
DK:\,\,\,\left\{ \begin{array}{l}
x + 1 \ge 0\\
1 - x > 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x \ge - 1\\
x < 1
\end{array} \right. \Leftrightarrow - 1 \le x < 1.\\
TXD:\,\,\,D = \left[ { - 1;\,1} \right).
\end{array}\]