Sigma Series Sumate To Infinity How do I summate to infinity? I know I need to give the equation in terms of "n" and split it up into two different summations and subtract them but I don't know how you can physically get a value up to infinity? !enter image description here

HINT:

$$\frac2{r^2-1}=\frac{r+1-(r-1)}{(r+1)(r-1)}=\cdots$$ which forms a Telescoping Series