Молю алгебра помогите !!!!!

Решите задачу:

$( \frac{x^2+y^2}{x^2-y^2} )^2:(( \frac{x+y}{x-y} + \frac{x}{y} )\cdot( \frac{x+y}{x-y} - \frac{y}{x}))= \\\ =( \frac{x^2+y^2}{x^2-y^2} )^2:( \frac{(x+y)y+x(x-y)}{y(x-y)} \cdot \frac{(x+y)x-y(x-y)}{x(x-y)} )= \\\ =( \frac{x^2+y^2}{x^2-y^2} )^2:( \frac{xy+y^2+x^2-xy}{y(x-y)} \cdot \frac{x^2+xy-xy+y^2}{x(x-y)} )= \\\ = \frac{(x^2+y^2)^2}{(x^2-y^2)^2} : \frac{(y^2+x^2)^2}{xy(x-y)^2}= \frac{(x^2+y^2)^2xy(x-y)^2}{(x^2-y^2)^2(y^2+x^2)^2} = \frac{xy(x-y)^2}{(x-y)^2(x+y)^2} =\frac{xy}{(x+y)^2}$