Really nice, but it supports only the very basics e.g
Plot[x^2, {x, -1, 1}, AxesLabel -> {x, y}, PlotStyle -> Dashed, Filling -> Bottom] ignores all options
And D can't compute JacobiP derivative even with
Simplify[
D[JacobiP[n, a, b, x], x] ==
1/2 (1 + a + b + n) JacobiP[-1 + n, 1 + a, 1 + b, x]]
It's startling how much work goes into something like Mathematica, too bad it's not open source, and have to be redone:(
I couldn't find a full table of compatibility with Mathematica though, anyone know where one is?