Here is the Leibniz formula Cameron spoke of last night: http://en.wikipedia.org/wiki/Leibniz_formula_for_pi and http://www.math.psu.edu/tseng/class/Calculation_of_Pi.doc and http://gradyiscool.googlepages.com/pi.gif and in the middle of the proof here: http://www.jstor.org/view/0025570x/di021167/02p0073q/0 Matt