# Infinite Series

1. Apr 15, 2010

### gmmstr827

Calculate the summation of i=1 to inf of the summation of j=i to inf of p^(j+i).
Yes, it is the summation of a summation. p^(j+i) can be seperated into (p^j)*(p^i).

2. Apr 15, 2010

### mathman

Write k=j-i, then you need to sum p2i+k with k=0 to ∞ and i=1 to ∞.