Re: Complex/imaginary numbers
- To: mathgroup at smc.vnet.net
- Subject: [mg6652] Re: [mg6614] Complex/imaginary numbers
- From: "w.meeussen" <w.meeussen.vdmcc at vandemoortele.be>
- Date: Wed, 9 Apr 1997 00:34:17 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
At 23:07 5-04-97 -0500, Heather Lyn Beegle wrote:
> Does anyone know how you can plot complex numbers/functions (both
>rectangular and polar) ? I've looked through the help, but so far I have
>not managed to get a plot of it.
>
> Thank you,
> Heather Beegle
>
>feel free to either post the answer or e-mail me at
>
> robertsn at wpi.edu
>
>
>
>
>
hi,
check: standard packages, add ons, Graphics`ComplexMap`
or else, maybe something like :
f[x_]:=2+3x-4x^2+5x^3
Table[ParametricPlot[
{Re[f[r E^(I fi)]],Im[f[r E^(I fi)]]}
,{fi,0,2 Pi},
PlotRange->{{-20,20},{-20,20}}],
{r,0,1.6,0.2}]
taking x as a complex argument, swinging 'round the unit circle Arg[x], and
modifying
the 'unit'circle radius (Abs[x]) stepwise.
Of course, if x is real and g[x] is complex, then it's trivial (just plot
both Re[g[x]] and Im[g[x]]
or Abs[g[x]] and Arg[g[x]] like:
g[x]:=E^(I x) f[x]
Plot[Evaluate at {Re[g[x]],Im[g[x]]},{x,0,2}]
a propos, if you ever have trouble with a plot, change 'Plot' to 'Table' and
check what's up.
Sometimes you need an 'Evaluate' to get y'r numbers out.
bye,
Dr. Wouter L. J. MEEUSSEN
eu000949 at pophost.eunet.be
w.meeussen.vdmcc at vandemoortele.be