2019-05-07 05:33:38 -0500 answered a question Bipolar coordinate system Thank you very much for your prompt and extended answer. I will need some time to adapt and modify it the analysed geometry. I have to solve the Helmholtz equation - in between. Once again - thanks. 2019-05-06 05:42:23 -0500 asked a question Bipolar coordinate system I want to extend some work presented in a paper "Analysis of TM and TE Modes in Eccentric Coaxial Lines Based on Bipolar Coordinate System" using SageMath. Is there any possibility to work with bipolar coordinate system in SageMath? Thanks 2019-03-07 05:43:39 -0500 received badge ● Student (source) 2019-03-07 05:06:38 -0500 asked a question Wrong output by plotting with SageMath Version 8.4.rc1 (Trusted) What is wrong? I got erroneous results by plots.  In: plot(sin(x)) Out: Graph - incorrect! In: plot(bessel_J(0, x), x, -0, 1) Out: Graph - incorrect!  I can send send you screenshots of both, but I don't how.