MHB Are the Accumulation Points of the Series $(-1)^n/[1 + (1/n)]$ Open at 1 and -1?

[Dustinsfl]

All numbers of the form $(-1)^n/[1 + (1/n)]$, $n\in\mathbb{Z}^+$.

$(-1)^n/[1 + (1/n)] = (-1, 1)$ is that true?

 

[CaptainBlack]

All numbers of the form $(-1)^n/[1 + (1/n)]$, $n\in\mathbb{Z}^+$.

$(-1)^n/[1 + (1/n)] = (-1, 1)$ is that true?

For what $n\in\mathbb{Z}^+$ does $-2/3=(-1)^n/[1 + (1/n)]$

CB

 

[Dustinsfl]

So the accumulation points are 1 and -1 and the set is open then.