Re: coupled ODE system: won't solve [?]

*To*: mathgroup at smc.vnet.net*Subject*: [mg6527] Re: [mg6503] coupled ODE system: won't solve [?]*From*: jpk at max.mpae.gwdg.de*Date*: Sun, 30 Mar 1997 22:24:05 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi Partric, take a moment of thinking -- if You request the analytical solution of a linear System of ODE's y'=A y Mathematica must find the eigenvalues & eigenvectors of A. Analytical even very complex expressions exist only for Dimensions[A]={4,4}. If Your system is lager than 4 (Yours is 8) Mathematica may or may not be able to find the eigenvalues and eigenvectors of A. Even the eigenvalues of a nearly full 4x4 matrix are an ugly nightmare of forlmulas. So it may not verry helpfull to You to see a solution of some dozend pages. And so it hits the ceiling in complexity of mathematics in general because no analytical formula for zeros of polynoms with order larger than 4 is known. Best regards Jens