Date: Mar 27, 2014 3:44 AM
Author: Torsten
Subject: Re: ode45
"Matthew" wrote in message <lgvf54$86b$1@newscl01ah.mathworks.com>...

> Hello,

>

> I'm trying to use ode45 to solve a set of differential equations.

> Rp = 5;

> global Rp

> [t, y] = ode45('odefunctions', [.001:.001:.8], V0);

>

> Where odefunctions is a separate m_file:

>

> function [dydt] = odefunctions(t, y)

>

> global Rp

> Qao_current = Rp*t

>

> dydt = ones(2,1)

> dydt(1) = (Qao_current/c) - (y(1)/(Rp*c));

> dydt(1) = (0/c) - (y(2)/(Rp*c));

>

> Within odefunctions I need to define a variable thats dependent on t. This does not seem to work... and putting a loop within odefunctions does not work either... Qao_current should change with every t

>

> Any suggestions?

>

> Thanks!

What are V0 and c ? You did not define these variables.

Initialize dydt as dydt=zeros(2,1).

Why do you set dydt(1) two times ?

Best wishes

Torsten.