I don't know that one, but I once had a pure math problem that used a square root, too. Does anyone know which one I'm thinking of? —Dan ----- I seem to recall a classical inventory management problem whose optimum solution involves a sqrt function. Since I never took a Operations Research course, I think that this problem showed up in a calculus class & used Lagrange multipliers. But after Googling a while, I couldn't find it. Anyone here recall a similar problem? -----