I am unsure as to how factorials should be expanded.(adsbygoogle = window.adsbygoogle || []).push({});

I have [tex]\sum[/tex][tex]\stackrel{1}{(2n!)}[/tex] (if what was just typed did not make sense due to html error on my part, it is supposed to say the sum of 1/(2n)!) from n=1 to infinity. I did the ratio test and found the limit to be 0, which is less than 1, which means this series is absolutely convergent. My fear is that I didn't expand the factorials properly and perhaps my answer is wrong. Could someone let me know if my answer makes sense?

FYI: (2n+2)! I expanded as (2n+2)(2n+1)(2n)!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# I am unsure of factorials

**Physics Forums | Science Articles, Homework Help, Discussion**