Question Number 182909 by SANOGO last updated on 16/Dec/22
![xε]−1,1[ calcul: Σ_(n=1) ^(+oo) (x^n /((1−x^n )(1−x^(n+1) )))](https://www.tinkutara.com/question/Q182909.png)
$$\left.{x}\epsilon\right]−\mathrm{1},\mathrm{1}\left[\:{calcul}:\right. \\ $$$$\underset{{n}=\mathrm{1}} {\overset{+{oo}} {\sum}}\frac{{x}^{{n}} }{\left(\mathrm{1}−{x}^{{n}} \right)\left(\mathrm{1}−{x}^{{n}+\mathrm{1}} \right)} \\ $$