[Date Index]
[Thread Index]
[Author Index]
Re: How to solve or approximate a first order differential equation ?
*To*: mathgroup at smc.vnet.net
*Subject*: [mg123224] Re: How to solve or approximate a first order differential equation ?
*From*: Bob Hanlon <hanlonr357 at gmail.com>
*Date*: Sun, 27 Nov 2011 04:13:56 -0500 (EST)
*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com
Clear[y];
data = {{1, 0.033}, {2, 0.054}, {5, 0.088}};
With[{C = 1/9},
Column[{
model = DSolve[
{y'[t] == -A (y[t])^2 + B (C - y[t]), y[0] == 0},
y[t], t][[1]],
param = FindFit[data, y[t] /. model, {A, B}, t],
Plot[y[t] /. model /. param, {t, 0, Max[data[[All, 1]]]},
ImageSize -> 400, AxesLabel -> {"t", "y[t]"},
Epilog -> {Red, AbsolutePointSize[5], Point[data]}]}]] // Quiet
Bob Hanlon
On Sat, Nov 26, 2011 at 5:09 AM, Dino <dinodeblasio at gmail.com> wrote:
> Hello everyone,
>
> I have this first order differential equation:
>
> y'[t] = -A (y[t])^2 + B (C - y[t])
>
> where A and B are unknown constants and C is known constant.
> One condition is y[0]==0
>
> A and B should be determined by fitting a list of {y[i],t[i]} values.
>
> For this reason i would like to approximate my differential equation
> with a function which I could use to fit the data and find A and B.
>
> I don't know how to do this.
> Any help is highly appreciated.
>
> Thanks,
Prev by Date:
**Tee-arrow notation for pure functions**
Next by Date:
**Re: Matrices as operators**
Previous by thread:
**How to solve or approximate a first order differential equation ?**
Next by thread:
**Re: How to solve or approximate a first order differential equation ?**
| |