I have a problem similar to this this thread

http://www.mathhelpforum.com/math-he...um-series.html

But my problem is

infinity

n=1

And I know that you use partial fractions and get

or

infinity

n=1

and expanded I have

And I have to find the sum of the series but when I do I get it is equal to

lim

n->infinity

and the answer is

What am I doing wrong?