See also "Derivative" (listed in the Integral web site) in v0.9 (v1.0 will be announced next week) : http://www.robertocolistete.net/Derivative/ It can also calculate grad, div, curl and laplacian in 3 coordinate systems (carthesian, cylindrical and spherical), which is very useful in electromagnetism calculations If you have some idea of specific software for electric/magnetic field, feel free to suggest it to me, I plan to write softwares like "Cinematics", "Eletric Potential", etc, targetting Maemo/MeeGo.