Need free program to plot expressions in polar coordinates

[morangta]

Homework Statement

Need a free program to plot expressions in polar coordinates. For example, I want to plot the equipotentials for an expression in polar coordinates of the potential for a dipole charge, 4q and -q separated by a distance L.

Homework Equations

V=kq(4/r₁ - 1/r), where r₁² = r²+ L² - 2rLcosθ.

The Attempt at a Solution

Octave and SciPy/matplotlib are posted online as two (2) good programs.


PS Thank you to Simon for guiding me to a solution for the sheet charge electric field problem I posted.

 

[tms]

You could try GNUPlot.