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## Re: Multiple variables in ode45

 From: Shai Ayal Subject: Re: Multiple variables in ode45 Date: Tue, 06 Dec 2005 19:00:23 +0200 User-agent: Thunderbird 1.5 (Windows/20051025)

```I'm not sure I understand -- is Vl a function or constant?
```
In general you e to solve your two equations (for u_dot and Vf_dot) simultaneously, and ide45 should be able to do this.
```
Shai

Ron Crummett wrote:
```
```Hi all -

```
I am trying to solve a differential equation with ode45 that has two input variables and one output, but one of the input variables is dependent on the other. When I try searching for anything like this it is to no avail (maybe I don't know what to search for).
```
Anyway, the equation is

u_dot = 0.5*e_dot+1.64*(e-1.14*Vf_dot)

```
where e = Vf-Vl, Vl is my input, and Vf is my output. The value of u is then fed into another system (which I do have the diff. eq. for) to get Vf, if that helps.
```
Could someone give me some pointers on how to do this?  Thanks.

-Ron

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