# Evaluate $\sum\limits_{i=0}^{n}\frac{1}{6^i}$

I'm asked to evaluate: $$\sum\limits_{i=0}^{n}\frac{1}{6^i}$$

Since it's a geometric series, I got $\dfrac{1-\frac{1}{6^n}}{\frac56}$ but I think it could be wrong.

• Did you check some simple cases? – Did Mar 15 '15 at 21:06
• @Henry yes I do mean the ∑ sign – Sean Dowling Mar 15 '15 at 21:10
• @Did What do you mean by some simple cases? I firstly wrote out the series, 1 + 1/6^1 + 1/6^2 – Sean Dowling Mar 15 '15 at 21:12
• Dunno... N=0 perhaps? Or N=1? Or even, let us be foolishly daring, N=2? – Did Mar 15 '15 at 21:14
• @Did for N=0 I get 0 for N=1 I get 7/6 – Sean Dowling Mar 15 '15 at 21:21