Помогите решить пожалуйста

$(\frac{y}{x-y}+\frac{x}{x+y}):(\frac{1}{x^2}+\frac{1}{y^2})-\frac{y^4}{x^2-y^2}=\frac{y(x+y)+x(x-y)}{(x-y)(x+y)}:\frac{y^2+x^2}{x^2y^2}-\frac{y^4}{x^2-y^2}=$

$=\frac{xy+y^2+x^2-xy}{(x-y)(x+y)}:\frac{y^2+x^2}{x^2y^2}-\frac{y^4}{x^2-y^2}=\frac{y^2+x^2}{(x-y)(x+y)}*\frac{x^2y^2}{y^2+x^2}-\frac{y^4}{x^2-y^2}=$

$=\frac{x^2*y^2}{x^2-y^2}-\frac{y^4}{x^2-y^2}=\frac{x^2*y^2-y^4}{x^2-y^2}=\frac{y^2(x^2-y^2)}{x^2-y^2}=y^2$

$(\sqrt{3})^2=3$

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