Hey everybody!

Really need some help cause I'm lost!

I need to find an asymptotically tight bound for this sum

http://img231.imageshack.us/img231/1606/32830911.jpg

, and I know u can't bound a sum, so I can't figure out a way to do it!! I'd REALLY appreciate if someone could explain to me (in the most simple way possible) what I need to do in a situation where I have a sum to bound)

THANK YOU!!!!

-1