Re: problems with DSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg99428] Re: problems with DSolve
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Tue, 5 May 2009 06:01:52 -0400 (EDT)
- Organization: Uni Leipzig
- References: <gtnk4s$3md$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
Hi,
may be that
Plot[Evaluate[
(x[t] /. DSolve[{x'[t] == y[t], y'[t] == -x[t], x[0] == 1, y[0]== 2}],
{x, y}, t]), {t, 0, 5}]
will work too.
Plot[] hat the attribute HoldAll.
Regards
Jens
szymon.stoma at gmail.com wrote:
> hello,
>
> i am new to mathematica, therefore sorry if my question is trivial. I
> would like to understand why the following line does not work:
>
> Plot[(x[t] /. DSolve[{x'[t] == y[t], y'[t] == -x[t], x[0] == 1, y[0]
> == 2}, {x, y}, t]), {t, 0, 5}]
>
> whereas after splitting into two lines it works:
> sol = DSolve[{x'[t] == y[t], y'[t] == -x[t], x[0] == 1, y[0] == 2},
> {x, y}, t]
> Plot[(x[t] /. sol), {t, 0, 5}]
>
> i would like to use Manipulate to play with boundary conditions, so
> the first notation would be highly useful.
>
> thanks a lot for any feedback.
>