Re: Re: PolarPlot
- To: mathgroup at smc.vnet.net
- Subject: [mg87510] Re: Re: [mg87484] PolarPlot
- From: Bruce Colletti <vze269bv at verizon.net>
- Date: Sat, 12 Apr 2008 06:55:54 -0400 (EDT)
Craig
Thankx for the reply. The code:
a = 2; PolarPlot[4 a^2 Cos@theta, {theta, 0, 2 Pi}]
only produces half the plot, since only theta values in [0,pi/2] and [3pi/2=
,2pi] can satisfy the function. The actual polar curve has two parts, each=
corresponding to a positive and negative value of r.
I don't see how to "easily" apply ParametricPlot (what would the parametric=
forms be for x and y?), although I may well be missing the obvious.
It seems that a "PolarContourPlot" command is what's needed, but no such th=
ing exists in Mathematica (I think).
Bruce
=====================
From: W_Craig Carter <ccarter at mit.edu>
Date: 2008/04/11 Fri AM 07:52:22 CDT
To: Bruce Colletti <vze269bv at verizon.net>
Cc: mathgroup at smc.vnet.net
Subject: [mg87510] Re: [mg87484] PolarPlot
Dear Bruce,
It doesn't appear that you are plotting what you say you wish to.
If I understand correctly, you are asking for
a = 2;
PlotPlot[4 a^2 Cos@theta, {theta, 0, 2 Pi}]
In your example, you are plotting two radial functions. Perhaps you were th=
inking of ParametricPlot?
On Fri, Apr 11, 2008 at 1:47 AM, Bruce Colletti <vze269bv at verizon.net> wrot=
e:
Re 6.0.2 under WinXP.
I'm using the command below to plot the polar equation r^2 = 4a^2 Cos@the=
ta. =C2 Is there a better way? =C2 Thankx.
Bruce
PolarPlot[{2 a Sqrt[Cos@t], -2 a Sqrt[Cos@t]}, {t, 0, 2 \[Pi]},
=C2 PlotRange -> 7]
--
W. Craig Carter