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MathGroup Archive 1997

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

  • To: mathgroup at
  • Subject: [mg6527] Re: [mg6503] coupled ODE system: won't solve [?]
  • From: jpk at
  • Date: Sun, 30 Mar 1997 22:24:05 -0500 (EST)
  • Sender: owner-wri-mathgroup at

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

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