Hi all, This is just wild shot, since my memory is not what it used to be ... I remembered reading about Feynman pointing out an interesting fact, that the integration of the gaussian function \int_-\infty^\infty e^(-x x) dx = \sqrt[\pi] has to do with Pi. He then went on to show the connection. I couldn't find out if this is in one of his Lecture books or his autobiography. I could find out where he mentioned the connection between exp and trig functions, but that was as far as I could go. I am not even sure that it was Feynman. Any idea? Thanks in advance, Michuco Ps. google feynman and integral leads, no surpise, to many links that have to do with his path integral.