MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

vertical lines in plot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg94100] vertical lines in plot
  • From: "Cristina Ballantine" <cballant at holycross.edu>
  • Date: Fri, 5 Dec 2008 05:28:24 -0500 (EST)

In plotting the inverse image of the unit circle under the function B 
below, I get all kinds of vertical lines. They are obviously jump 
discontinuities, very likely caused by choices of branch cuts. I there any 
way of getting rid of the vertical lines without redefining the brunch 
cuts? I looked at the value of different solutions in sol4 close to a 
point of discontinuity and it looks like the order of the solutions is 
switched when t gets to that point. I am not sure if this is just a 
coincidence. I also tried ExclusionsStyle->Red but there don't seem to be 
any exclusions. 


alpha := Pi/3
r := 2/3
a := r*Exp[I*alpha]
n := 3

B[z] := 1/(z^n)*((Conjugate[a]/a)*(a^2 - z^2)/(1 - (Conjugate[a])^2*z^2))^n

sol4 := Solve[B[z] == Exp[I*t], z]

ParametricPlot[Evaluate[{Re[z], Im[z]} /. sol4], {t, 0, 2 Pi}, PlotRange -> All]

Best regards,

Cristina



  • Prev by Date: Re: A plot of Sign[x]
  • Next by Date: Re: A plot of Sign[x]
  • Previous by thread: Re: Newbie question: Which is more versatile, Table[] or Array[]?
  • Next by thread: Re: vertical lines in plot