\[\boxed{\mathbf{626}.}\]
\[1)\ \sqrt{x^{2} - 1} > 1;\]
\[\left( \sqrt{x^{2} - 1} \right)^{2} > 1^{2};\]
\[x^{2} - 1 > 1;\]
\[x^{2} > 2;\]
\[x < - \sqrt{2}\ \ и\ \ x > \sqrt{2};\]
\[Выражение\ имеет\ смысл\ при:\]
\[x^{2} - 1 \geq 0;\]
\[x^{2} \geq 1;\]
\[x \leq - 1\ \ и\ \ x \geq 1;\]
\[Ответ:\ \ x < - \sqrt{2};\ \ x > \sqrt{2}.\]
\[2)\ \sqrt{1 - x^{2}} < 1;\]
\[\left( \sqrt{1 - x^{2}} \right)^{2} < 1^{2};\]
\[1 - x^{2} < 1;\]
\[- x^{2} < 0;\]
\[x^{2} > 0;\]
\[x \neq 0;\]
\[Выражение\ имеет\ смысл\ при:\]
\[1 - x^{2} \geq 0;\]
\[x^{2} - 1 \leq 0;\]
\[(x + 1)(x - 1) \leq 0;\]
\[- 1 \leq x \leq 1;\]
\[Ответ:\ - 1 \leq x < 0;\ \ 0 < x \leq 1.\]
\[3)\ \sqrt{25 - x^{2}} > 4;\]
\[\left( \sqrt{25 - x^{2}} \right)^{2} > 4^{2};\]
\[25 - x^{2} > 16;\]
\[- x^{2} > - 9;\]
\[x^{2} < 3;\]
\[- 3 < x < 3;\]
\[Выражение\ имеет\ смысл\ при:\]
\[25 - x^{2} \geq 0;\]
\[x^{2} - 25 \leq 0;\]
\[(x + 5)(x - 5) \leq 0;\]
\[- 5 \leq x \leq 5;\]
\[Ответ:\ \ - 3 < x < 3.\]
\[4)\ \sqrt{25 - x^{2}} < 4;\]
\[\left( \sqrt{25 - x^{2}} \right)^{2} < 4^{2};\]
\[25 - x^{2} < 16;\]
\[- x^{2} < - 9;\]
\[x^{2} > 9;\]
\[x < - 3\ \ и\ \ x > 3;\]
\[Выражение\ имеет\ смысл\ при:\]
\[25 - x^{2} \geq 0;\]
\[x^{2} - 25 \leq 0;\]
\[(x + 5)(x - 5) \leq 0;\]
\[- 5 \leq x \leq 5;\]
\[Ответ:\ \ - 5 \leq x < - 3;\ \ \]
\[3 < x \leq 5.\]