Hi all,

I need a little help with this summation problem.

Find the value of,

For,

I tried to solve it like this,

What is the series,

.

Its clearly not a A.P. It also doesn't seem like a G.P. How do I calculate the sum of such a series?

Thanks for your help.

P.S. Latex doesn't work anymore. I used QuickLatex to explain the problem.