# PolarPlot with Dashed and PlotRange freezes for simple function

When I plot

PolarPlot[1/(1+Cos[6-t]), {t,0,2\[Pi]}, PlotRange->{{-4,4},{-4,4}}, PlotStyle->Dashed]


everything works normally, but when I change the numerator to 2,

PolarPlot[2/(1+Cos[6-t]), {t,0,2\[Pi]}, PlotRange->{{-4,4},{-4,4}}, PlotStyle->Dashed]


this causes Mathematica to freeze and have to kill the process. Any idea what is going on?

I'm using 10.0.0 on Linux, but I had the same issue with 10.0.0 OSX.

If I take away the PlotStyle, it works. If I take away PlotRange, it works. If I change Cos[6-t] to Cos[t], it works.

• Good question. Actually this happens with the first plot as well for me, with Mathematica 10.0.0 and OS X. Changing Cos[6-t] to Cos[t] does not resolve it for me either. – C. E. Nov 11 '14 at 1:21
• on V10.1 windows 7, I get no crash and empty plot? !Mathematica graphics ps. for problem like this it is best to give version number and platform. – Nasser Nov 11 '14 at 1:27
• It gives two nice blank plots on V9 – Dr. belisarius Nov 11 '14 at 2:44
• ^edited to add version number(s) -- 10.0.0 on Linux (but I see the same behavior with 10.0.0 on OSX) – Jacob Schwartz Nov 12 '14 at 2:20

Too long for a comment and maybe just an observation.

I'm on 10.0 for Mac OS X x86 (64-bit) (September 10, 2014) and have also a kind of freeze, the rainbow shell comes up and rotates for 10-15 seconds. This effect again fetches 3-5 times. Very uncomfortable ...

But if I set PlotRange -> 4 and Performance Goal -> "Speed" I have not freeze at all.

PolarPlot[1/(1 + Cos[6 - t]), {t, 0, 2 \[Pi]}, PlotRange -> 4,
PlotStyle -> Dashed, PerformanceGoal -> "Speed"]


PolarPlot[2/(1 + Cos[6 - t]), {t, 0, 2 \[Pi]}, PlotRange -> 4,
PlotStyle -> Dashed, PerformanceGoal -> "Speed"]


• Thanks @Lou, the PerformanceGoal option causes it not to freeze up. – Jacob Schwartz Nov 12 '14 at 2:23
• @Jacob Schwartz, My pleasure! – user9660 Nov 12 '14 at 3:58
• (+1) This workaround works for MMa 10.0.1 under Win7 x64. – Alexey Popkov Nov 12 '14 at 10:38

the plot is empty when the upper limit of t is 2 Pi. I am not sure why. also I got problem when the PlotStyle->Dashed. Not sure why.

This gives the plot.

PolarPlot[2/(1 + Cos[6 - t]), {t, 0, 2 \[Pi] - .1}, AspectRatio -> 1,
PlotRange -> {{-40, 40}, {-10, 10}}, PlotStyle -> Red]


• A funny thing. If I try to repeat the above solution, if works. It still works with the option PlotRange -> {{-4, 10}, {-5, 5}} . And with such an option one can make sure that the maximum value of x is about one. Therefore, I expect that the option PlotRange -> {{-4, 2}, {-5, 5}}  will simply give a more detailed view. Instead I see an empty plot. It is Mma 10.0, Win7. Looks very much like a bug for me. – Alexei Boulbitch Nov 11 '14 at 9:10