Re: Plotting complex functions
- To: mathgroup at smc.vnet.net
- Subject: [mg23985] Re: Plotting complex functions
- From: "Kevin J. McCann" <kevinmccann at home.com>
- Date: Mon, 19 Jun 2000 01:45:28 -0400 (EDT)
- References: <8ihvf8$lgj@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Matthijs ,
In order to plot, the function has to produce numbers. Your example below
has two undetermined integration constants; so, the result will not produce
a number. Try the example below. I picked the IC's so that the result would
be complex.
Paste these into a NB
f=y/.DSolve[{y''[t] + y'[t] + y[t] == 0,y[0]==I,y'[0]==1}, y, t]
ParametricPlot[{Re[f[x]], Im[f[x]]}, {x, 0, 10},
Epilog -> {RGBColor[1, 0, 0], AbsolutePointSize[5],
Point[{Re[f[0.]], Im[f[0.]]}]}];
Cheers,
Kevin
"Matthijs Sypkens Smit" <matthijs at helena.tux.nu> wrote in message
news:8ihvf8$lgj at smc.vnet.net...
> Hi,
>
> How do I make a plot of a complex-valued function, such as y after
> DSolve[y''[t] + y'[t] + y[t] == 0, y, t]
>
> I've tried a ParametricPlot with Re[y[t] and Im[y[t], but either that
> doesn't work or I'm doing it wrong. Any pointers or an example?
>
> --
> Matthijs
>