From: "Sridatta Pasumarthy" <>
Newsgroups: comp.soft-sys.matlab
Subject: Solving second order differential equations
Date: Thu, 25 Nov 2010 16:48:04 +0000 (UTC)
Organization: IIT Delhi
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How do i solve four differential equations of second order involving many variables (numerically)?
I have referred van der pol (non-stiff) example in Matlab, but it didn't help much because i couldn't
figure a way to convert these to first order right away. Please help me find a solution.

Problem Structure
w' = [k*f(z)] * y'
w * x'' = c*g(z) * y'
w * y'' = f(z) + g(z) * x' + j(z) * z'
w * z'' = c*j(z) * y'
1-(1/sqrt(w))=x'^2 + y'^2 + z'^2

x(0)=0, y(0)=0, z(0)=0, dx/dt(0)=0, dy/dt(0), dz/dt(0)=v
c,k,v are constants.
It also doesn't help that f,g,j are complicated exponential functions based upon z.

I am supposed to plot 'dw/dz' vs 'z'