i tried but i'm stuck it seems too difficult for me
why is this even true? please. help me.
For any $\alpha \in \mathbb{R}$ and $n \in \mathbb{N}$ $$ \sum_{p=1}^n \frac{\sin(\alpha+ 2\pi p / n) }{x^2-2\cos(\alpha+2\pi p/n)xy + y^2} = \frac{\sin(\alpha) x^{n-1}y^{n-1}}{x^{2n}-2x^ny^n \cos(\alpha) + y^{2n}} $$