$$\frac{1}{x-y}+\frac{y}{x^{y}}+\frac{2xy}{x^{2}+y^{2}}$$
$\frac{xy^{3}+x^{y+2}-y^{4}+y^{2}x^{y}-2y^{2}x^{y+1}+yx^{3}+2yx^{y+2}-\left(xy\right)^{2}}{\left(x-y\right)\left(x^{2}+y^{2}\right)x^{y}}$
