SymPy is a Python library for symbolic mathematics. If you are new to SymPy, start with the Tutorial.
This is the central page for all of SymPy’s documentation.
The Installation section doesn’t apply to Pythonista, SymPy is already completely integrated.
SymPy is a very large package, and the first import can be somewhat slow on an iOS device (up to 10 seconds are not uncommon). After importing it for the first time, performance should be much better though.
Some pages refer to the SymPy live shell, which is integrated in the online version of the SymPy documentation, but not in Pythonista’s offline docs.