Question 1035433
<pre>

I think the best method for you is to write the answers
out and see. Plug in n=1 for the first term, n=2 for the
second, etc.,

{{{A[n]=1/(2n+1)}}} = 1/3 + 1/5 + 1/7 + ...
{{{A[n]=1/(2n-1)}}} = 1/1 + 1/3 + 1/5 + ...
{{{A[n]=n/(2n-1)}}} = 1/1 + 2/3 + 3/5 + ...
{{{A[n]=n/(2n+1)}}} = 1/3 + 2/5 + 3/7 + ...

Now you know which one it is.

Edwin</pre>