Originally Posted by

**orendacl** confirm is this one divergent?

inf x!

sum ------------------------

x=1 1 * 3 * 5 ... ( 2 x -1)

I said that we should start by replacing all n with n+1

Then we multiply an+1 by the reciprocal of an

That leads me to a messy fraction.

I get all messed up with a fraction that looks like:

(x+1)(2x-1)

-----------

2x+1

I come up with the series is divergent but due to abs value of ratio an+1 to an.

How do you solve this so the fraction obtained after the reciprocal is one that is easily taken a limit of to determine divergence or convergence?