       Re: request help

• To: mathgroup at smc.vnet.net
• Subject: [mg33110] Re: [mg33088] request help
• From: Tomas Garza <tgarza01 at prodigy.net.mx>
• Date: Sun, 3 Mar 2002 06:30:36 -0500 (EST)
• References: <200203011152.GAA27841@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```I suggest you take a look at NDSolve in the Help Browser, or in The Book. I
quote: "NDSolve[eqns, y, {x, xmin, xmax}] finds a numerical solution to the
ordinary differential equations eqns for the function y with the independent
variable x in the range xmin to xmax". And also "NDSolve gives results in
terms of InterpolatingFunction objects". So there should be no problem.
Using the right notation, since f[x] is a known function I take an
artificial example, e.g., f[x] = x^2, and any initial conditions:

In:=
NDSolve[{y''[x] == x^2*y[x] + Cos[x],
y' == 1, y == 1}, y[x], {x, 0, Pi}]

Out=
{{y[x] -> InterpolatingFunction[][x]}}

Now, I trust you know how to use the solution in terms of rules and
interpolation function. Otherwise, you must go back to basics.

Tomas Garza
Mexico City
----- Original Message -----
From: <luigi.rosa at tiscali.it>
To: mathgroup at smc.vnet.net
Subject: [mg33110] [mg33088] request help

> Hi!
> I'm a student of L'Aquila.
> I have a little problem: I have to solve an ordinary diff.
equation(numerically)
> with mathematica such as
> y''(x)=f(x) y(x) + cos(x) where y(x) is the unknown and f(x) is a known
> function which I Obtained as a numerical solution of another ord.
diffrential
> equation .
>
> May you send me an example of doing this?
>
> Thank u in advance.
>                             Luigi
>
> ps
> sorry... i do not speak english very well...i'm italian!!!
>
>
>
>
>
> __________________________________________________________________
> Abbonati a Tiscali!
> Con Tiscali By Phone puoi anche ascoltare ed inviare email al telefono.
> Chiama Tiscali By Phone all' 892 800        http://byphone.tiscali.it
>
>
>
>
>

```

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