"Jmath is a Computer Algebra System(CAS) for highschool students.
Here are some key features of Jmath:
- Plot mathematical functions.
- Solve equations.
- Find intersection.
- Show min/max points.
- Plot tangent to function.
- Find derivative.
- and more..."
"Mathics is a general-purpose computer algebra system. Enter queries and submit them by pressing Shift + Return. See the gallery for some neat examples or the documentation for a full list of supported functions. Mathics uses MathJax to display beautiful math."
"Mathics is a free, general-purpose online computer algebra system featuring Mathematica-compatible syntax and functions. It is backed by highly extensible Python code, relying on SymPy for most mathematical tasks and, optionally, Sage for more advanced stuff. Get Python if you don't have it already (you probably have it if you're on Linux or a Mac)."