Xcas


Xcas is a user interface to Giac, a free, open source basic Computer Algebra System for Microsoft Windows, Apple macOS and Linux/Unix; Xcas is written in C++. Giac can be used directly inside software written in C++.
Giac has a compatibility mode with WolframAlpha, Mathematica, Maple, MuPAD, Matlab, Yacas, SageMath, Qcas, ExpressionsinBar and Magma, CPMP-Tools, WordMat software and TI-89, TI-92, Voyage 200 and TI-Nspire calculators. Users can use Giac/Xcas as well as a free software compatible with Maple to develop formal algorithms or use it in other software. Xcas is used in SageMath for calculus operations. Among other things Xcas can solve equations and draw graphs. There is a forum for questions about Xcas.
CmathOOoCAS, an OpenOffice.org plugin which allows formal calculation in Calc spreadsheet and Writer word processing, uses Xcas to perform calculations.

Features

Here is a brief overview of what Xcas is able to do:
Read more commands and features here: http://www-fourier.ujf-grenoble.fr/~parisse/giac/cascmd_en.pdf

Xcas works for these operation Systems

Xcas and Giac are open-source projects developed by Bernard Parisse et al. at the Joseph Fourier University of Grenoble, France, since 2000. Xcas and Giac are based on experiences gained with Parisse's former project Erable.
In 2013 the mathematical software Xcas was also integrated into GeoGebra's CAS view.
Since 2013 there are videos showing how Xcas works.
Pocket CAS and CAS Calc P11 utilize Giac.
The system was also chosen by Hewlett-Packard as the CAS for their HP Prime calculator, which utilizes the Giac/Xcas 1.4.9 engine under a dual-license scheme.