\[\boxed{\mathbf{750}\mathbf{.}}\]
\[y = \arcsin x;\]
\[возрастает\ на\ \lbrack - 1;\ 1\rbrack.\]
\[1)\arcsin\frac{1}{\sqrt{3}} < \arcsin\frac{2}{\sqrt{10}}\]
\[\frac{1}{\sqrt{3}} < \frac{2}{\sqrt{10}}\]
\[\frac{1}{3} < \frac{4}{10}\]
\[\frac{1}{3} < \frac{2}{5}\]
\[\frac{5}{15} < \frac{6}{15}.\]
\[2)\arcsin\left( - \frac{2}{3} \right) > \arcsin\left( - \frac{3}{4} \right)\]
\[- \frac{2}{3} > - \frac{3}{4}\]
\[\frac{2}{3} < \frac{3}{4}\]
\[\frac{8}{12} < \frac{9}{12}.\]