Apr 15, 2012 Thread starter Banned #1 P Poirot Banned Feb 15, 2012 250 Find the sum to infinity of the series $1 +2z +3z^2+4z^3+.......$
Apr 15, 2012 Moderator #2 Opalg MHB Oldtimer Staff member Feb 7, 2012 2,800 Integrate it, find the sum of the integrated series, then differentiate it.
