Date: Mar 28, 2014 3:18 AM
Author: Torsten
Subject: Re: Third order non-linear boundary value problem
"Rachel " <rachel-dore20@hotmail.com> wrote in message <lh1o34$9lh$1@newscl01ah.mathworks.com>...

> Hey guys,

>

> I'm having a lot of trouble trying to get a numerical solution the the following boundary value problem,

>

> f'''+1/3ff''+1/3f'^2=0

>

> with the following boundary conditions,

>

> eta=0, f=0 & f''=0

> eta=infintiy, f'=0

>

> I am new to Matlab and I'm completely lost so your help would be much appreciated. I think this is how I set it up but I'm not sure??

>

> function dfdeta = mat4ode(eta,f)

> dfdeta = [ f(2)

> f(3)

> -1/3*f(1)*f(3)-1/3*Y(2)*Y(2) ];

>

> and for the boundary conditions,

>

> function res = mat4bc(ya,yb)

> res = [ ya(3)

> ya(1)

> yb(2)];

>

> And this is an attempt at the rest the code,

>

> function mat4bvp(solver)

>

> if nargin < 1

> solver = 'bvp4c';

> end

> bvpsolver = fcnchk(solver);

>

> infinity = 3;

>

> solinit = bvpinit(linspace(0,infinity,5),[0,0,0]);

>

> sol = bvpsolver(@mat4ode,@mat4bc,solinit);

>

> eta = sol.x;

> f = sol.y;

>

> figure(1)

> plot(eta,f)

> legend('F_1', 'F_2', 'F_3', 3)

> grid

>

> end

>

> I would be very grateful for the help. Thanks a mill.

>

> Rachel

There is no need to use bvp4c for your boundary value problem.

The solution is simply f=0.

Best wishes

Torsten.