\[\left( \frac{1}{x} + \frac{1}{y} \right) \cdot \frac{x - y}{\sqrt{2}} =\]
\[= \frac{(x + y)(x - y)}{\text{xy}\sqrt{2}} = \frac{x^{2} - y^{2}}{\sqrt{2}\text{xy}}\ \]
\[x = \sqrt[4]{5 + 2\sqrt{6}};\ \ \ y = \sqrt[4]{5 - 2\sqrt{6}}:\]
\[= \sqrt{5 + 2\sqrt{6}} - \sqrt{5 - 2\sqrt{6}} =\]
\[xy = \sqrt[4]{5 + 2\sqrt{6}} \cdot \sqrt[4]{5 - 2\sqrt{6}} =\]
\[= \sqrt[4]{\left( 5 + 2\sqrt{6} \right)\left( 5 - 2\sqrt{6} \right)} =\]
\[= \sqrt[4]{\left( \sqrt{2} + \sqrt{3} \right)^{2} \cdot \left( \sqrt{2} - \sqrt{3} \right)^{2}} =\]
\[= \sqrt[4]{\left( \left( \sqrt{2} + \sqrt{3} \right)\left( \sqrt{2} - \sqrt{3} \right) \right)} =\]
\[= \sqrt[4]{\left( \left( \sqrt{2} \right)^{2} - \left( \sqrt{3} \right)^{2} \right)} =\]
\[= \sqrt[4]{(2 - 3)^{2}} = \sqrt[4]{( - 1)^{2}} = 1\]
\[\frac{x^{2} - y^{2}}{\sqrt{2}\text{xy}} = \frac{2\sqrt{2}}{\sqrt{2} \cdot 1} = 2.\]