Solve / NSolve take too much time or fail

*To*: mathgroup at smc.vnet.net*Subject*: [mg60847] Solve / NSolve take too much time or fail*From*: "grimey" <tfgeyer at yahoo.com>*Date*: Fri, 30 Sep 2005 03:57:14 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hello, I'm working with Mathematica (version 5.0) for perhaps 3 month. And now I have a problem, I try to solve an equation like this: cf=(a1*x (a2 + a3*x + a^2))/(b1 + b2*x - b3*x^2 + b4*x^3); w=(1-c1*Sqrt[1-(1-c1^2)*x/c2])^2 / (1-c1)^2; This is the main equation: Solve[Numerator[cf]-I d1 w Denominator[cf]==0,x] And even after hours of working I don't get any solution, whether I take Solve or NSolve. And I gave a lot of virtual memory free for Mathematica to work with. Are there any tricks to help solving difficult polynomial equations faster (or at all)? I want to get, of course, a set of Root-functions for x (complex), depending on a1, a2, a3, b1, b2, b3, b4, c1, c2, d1, so I have no numerical number to start with for the FindRoot-function. Can anyone help me? Some other equations, not always that different from this one, could be solved more easily... Thank you very much! Thomas Geyer (tfgeyer at yahoo.com)