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Xcas

Xcas is a user interface to Giac, which is an open source computer algebra system (CAS) for Windows, macOS and Linux among many other platforms. Xcas is written in C++. Giac can be used directly inside software 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. 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 Giac to perform calculations.

Features

Here is a brief overview of what Xcas' features:

Example Xcas commands:

  • produce mixed fractions: <code>propfrac(42/15)</code> gives 2 +
  • calculate square root: <code>sqrt(4)</code> = 2
  • draw a vertical line in coordinate system: <code>line(x=1)</code> draws the vertical line in the output window
  • draw graph: <code>plot(function)</code> (for example, <code>plot(3 * x^2 - 5)</code> produces a plot of
  • calculate average: <code>mean([3, 4, 2])</code> is 3
  • calculate variance: <code>variance([3, 4, 2])</code> is
  • calculate standard deviation: <code>stddev([3, 4, 2])</code> is
  • calculate determinant of a matrix: is
  • calculate local extrema of a function: <code>extrema(-2*cos(x)-cos(x)^2,x)</code> is [0, π]
  • calculate cross product of two vectors: <code>cross([1, 2, 3], [4, 3, 2])</code> is
  • calculate permutations: <code>nPr()</code>
  • calculate combinations: <code>nCr()</code>
  • solve equation: <code>solve(equation,x)</code>
  • factoring polynomials: <code>factor(polynomial,x)</code> or <code>cfactor(polynomial,x)</code>
  • differentiation of function: <code>diff(function,x)</code>
  • calculate indefinite integrals/antiderivatives: <code>int(function,x)</code>
  • calculate definite integrals/area under the curve of a function: <code>int(function,x,lowerlimit,upperlimit)</code>
  • calculate definite integral (also called solid of revolution) - finding volume by rotation (around the x-axis): <code>int(pi*function^2,x,lowerlimit,upperlimit)</code>
  • calculate definite integral (also called solid of revolution) - finding volume by rotation (around the y-axis) for a decreasing function: <code>int(2*pi*x*function,x,lowerlimit,upperlimit)</code>
  • separation of variables: <code>split((x+1)*(y-2),[x,y])</code> produces
  • desolve differential equation (the derivatives are written as y or y): <code>desolve(differential equation,y)</code>

Supported operating systems

History

Xcas and Giac are open-source projects developed and written by and Renée De Graeve at the former Joseph Fourier University of Grenoble (now the Grenoble Alpes University), France since 2000. Xcas and Giac are based on experiences gained with Parisse's former project Erable. 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 1.5.0 engine under a dual-license scheme.

In 2013, the mathematical software Xcas was also integrated into GeoGebra's CAS view.

Use in education

Since 2015, Xcas is used in the French education system. Xcas is also used in German universities, and in Spain and Mexico. It is also used at the University of North Carolina Wilmington and the University of New Mexico. Xcas is used in particular for learning algebra.

"χCAS" port for graphing calculators

There is a port of Giac/Xcas for certain graphing calculator models, called χCAS (KhiCAS) , installed or "sideloaded" as a 3rd party application. (As opposed to an officially distributed or supported component of the calculators' OS, as is the case for some HP calculators' Xcas integration)

Casio graphing calculators were the first to support Xcas ("KhiCAS"), as a 3rd party CAS engine on the fx-CG Prizm series, including the fx-CG50 and 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.

Xcas is also available for the TI Nspire CX, CX-II, and Numworks N0110

In 2024, a special cut-down version was released for the TI-84+ CE and some variants from Texas Instruments. Other models that Xcas supports bear 32-bit systems, standing in contrast to the TI-84+ CE's much older 8-bit Zilog Z80-based CPU. These comparatively limited hardware resources necessitated the removal of some features to make the port possible. While Casio and NumWorks graphing calculators are not uncommon in France, from where Xcas author Bernard Parisse hails, TI-84+ CE support makes Xcas much more relevant in the United States, where Texas Instruments holds a monopoly on graphing calculators used in education.

See also

References

Further reading

External links