Figure 1. Xcas is able to calculate fractions that do not have a common denominator.
Figure 2. Xcas is able to solve equations, calculate derivatives, and calculate antiderivatives.
Figure 3. Xcas is able to solve differential equations.
Xcas is a user interface to Giac, which is an open sourcecomputer algebra system (CAS) for Windows, macOS and Linux among many other platforms. Giac can be used directly inside software written in C++; Xcas itself is written in C++.
Xcas has compatibility modes with many popular algebra systems like WolframAlpha, Mathematica, Maple, or MuPAD. Users can use Giac/Xcas to develop formal algorithms or use it in other software. Giac is used in SageMath for calculus operations. Among other things, Xcas can solve differential equations (Figure 3) and draw graphs.
The system was also chosen by Hewlett-Packard as the CAS for their HP Prime calculator, which utilizes the Giac/Xcas 1.5.0 engine under a dual-license scheme. In 2013, Xcas was also integrated into GeoGebra's CAS view.
χCAS (also known as KhiCAS) is a port of Giac/Xcas for certain graphing calculator models that is installed or "sideloaded" as a 3rd party application. (This is as opposed to an officially distributed or supported component of the calculators' OS, as is the case for some HP calculators' Χcas integration.)
Casio graphing calculators were the first to support χCAS ("KhiCAS"), as a 3rd party CAS engine on the fx-CG Prizm series, including the fx-CG50 and its successor fx-CG100. Outside of the Prizm series, select models in the Casio 9860 series are supported as well, including the fx-9750GIII and fx-9860GIII. None of these models have their own computer algebra system.
In 2024, a special cut-down version was released for the TI-84+ CE and some variants from Texas Instruments. Other models that χCAS supports bear 32-bit systems, standing in contrast to the TI-84+ CE's much older 8-bitZilog Z80-based CPU. These comparatively limited hardware resources necessitated the removal of some features to make the port possible.
12Tõnisson, Eno (2017-11-09). Differences between expected answers and the answers offered by computer algebra systems to school mathematics equations (Thesis). hdl:10062/58398.
↑Gandit, Michèle (2009). Bardini, C.; Fortin, P.; Oldknow, A.; Vagost, D. (eds.). Experimenting and proof in mathematics with XCAS. Proceedings of the 9th International Conference on Technology in Mathematics Teaching. Metz, France.
↑Fekih, Lassaad Ben; Verlinden, Olivier; Kouroussis, Georges (2011). Development of a user-friendly and open-source multibody framework with the help of symbolic tools. 4th International Congress Design and Modelling of Mechanical Systems. Sousse (Tunisia).