\[\left( \frac{1^{\backslash x + y}}{x - y} - \frac{1^{\backslash x - y}}{x + y} \right) \cdot \frac{x^{2} - y^{2}}{y^{2}} =\]
\[= \frac{x + y - x + y}{(x - y)(x + y)} \cdot \frac{x^{2} - y^{2}}{y^{2}} =\]
\[= \frac{2y\left( x^{2} - y^{2} \right)}{\left( x^{2} - y^{2} \right) \cdot y²} = \frac{2}{y}\]