Re: PolarPlot

*To*: mathgroup at smc.vnet.net*Subject*: [mg87678] Re: PolarPlot*From*: Helen Read <hpr at together.net>*Date*: Tue, 15 Apr 2008 05:54:28 -0400 (EDT)*References*: <ftmu5p$50d$1@smc.vnet.net> <ftv938$80f$1@smc.vnet.net>*Reply-to*: HPR <read at math.uvm.edu>

dh wrote: > Hi Bruce, > > the radius in polar coordinates has to be real and positive. Therefore, Actually, no. In polar coordinates r is a *directed* distance, which may be positive or negative. > r=Sqrt[Cos[phi]] can not be the correct formula, we would get imaginary > > values. To prevent this, we may e.g. write: r=Sqrt[Abs[Cos[phi]] what > > gives the plot you are looking for. > > hope this helps, Daniel -- Helen Read University of Vermont