SymPy is the best!

In addition to the already-excellent official tutorial https://docs.sympy.org/latest/tutorial/index.html , I have written a short printable tutorial summary of the functions most useful for students https://minireference.com/static/tutorials/sympy_tutorial.pd...

For anyone interested in trying SymPy without installing, there is also the online shell https://live.sympy.org/ which works great and allows you to send entire computations as a URL, see for example this comment that links to an important linear algebra calculation: https://news.ycombinator.com/item?id=23158095