Can you check to see if i expressed the sums in closed form correctly?

[mr_coffee]

Hello everyone, I was wondering if someone can double check my work for #'s 25 and 31.

The directions say:
Express each of the sums in closed form (without using a summation symbol and without using an ellipis...).http://img224.imageshack.us/img224/3514/lastscanle2.jpg
Thanks!

 

[Office_Shredder]

You used the index from the sum instead of the limit. So 25 should be 5^m not 5ⁱ

Also, 31 is (1 + 1/2)ⁿ, which means not only should you have gotten 3/2ⁿ, but it should have been (3/2)ⁿ

 

[mr_coffee]

thanks a lot for catching those errors!