\[\begin{array}{l} {\text{Упростите:}} \hfill \\ \left( {\frac{{{m^{\frac{1}{2}}} + {n^{\frac{1}{2}}}}}{{{m^{\frac{1}{2}}} - {n^{\frac{1}{2}}}}} - \frac{{{m^{\frac{1}{2}}} - {n^{\frac{1}{2}}}}}{{{m^{\frac{1}{2}}} + {n^{\frac{1}{2}}}}}} \right):\frac{{{{\left( {\sqrt m - \sqrt n } \right)}^{ - 1}}}}{{{m^{ - \frac{1}{2}}} + {n^{ - \frac{1}{2}}}}}. \hfill \\ \end{array}\]