This number, the Product[Cos[Pi/n], {n,3,infinity}] is the limit of an interesting figure in geometry.: If we take a circle, inscribe a triangle, then incribe another circle inside the triangle, then inscribe a square inside the inner circle, then inscribe another circle inside the square, then inscribe a pentagon... The radius of this figure (the number of sides of the polygon increase with every step:triangle 3, square 4, pentagon 5, ...) approaches a limit: Product[Cos[Pi/n], {n,3,infinity}] Is there any way to get an analytic solution to this? Like this would be the square root of Pi or some combination of radicals and irrational numbers? Anyway, Thanks, Mounitra Chatterji mounitra@seas.ucla.edu mentioned in december 1995. By Mounitra Chatterji .1149420448532962007010401574695987428307953372008635168440233965; maple routine --> product(cos(Pi/n),n=3..infinity);evalf(",64); ------------------------------------------------------------------ see also the interesting page : http://www.astro.virginia.edu/~eww6n/math/p2node32.html#SECTION000032 and also http://pauillac.inria.fr/algo/bsolve/infprd/infprd.html # This is the electronic signature for Plouffe's Inverter # # Ceci est la signature électronique pour l'Inverseur de Plouffe # # Copyright : Simon Plouffe/Plouffe's Inverter (c) 1986. # # http://www.lacim.uqam.ca/pi #