Overview

- GUYacas is a graphical user interface (GUI) on Windows platforms to the Yacas computer algebra system.
- GUYacas can be downloaded by clicking here

- GUYacas is "selfcontained" in the sense that it is NOT necessary
to install Yacas for GUYacas to work.

- GUYacas requires that "Microsoft .NET Framework Version 2.0" is installed on your computer. The .NET Framwork can be downloaded here. (Note: You may need to have administrative rights on your computer to make the installation).
- Yacas is described in numerous places on the internet, for
example at http://en.wikibooks.org/wiki/Programming/LearnByExample/Yacas
and http://en.wikipedia.org/wiki/Yacas

- Yacas comes with a comprehensive documentation (300+ pages) which includes many examples. Some examples are given here.

There is a code mode (see screenshot) and an interactive mode (see screenshot) of GUYacas.

- Code mode: In code mode, the entire content of the script window is submitted with ctrl-y. If some lines are highlighted, only these lines are submitted with ctrl-y. The result appears in the output window.
- Interactive mode: In
interactive mode, lines are submitted one at the time and the result
appears in the output window.

In the program group (Start -> Programs -> GUYacas) there is a help file with various scripts.

Scripts

A GUYacas script (for use in code mode) could look like as follows (note that # is used for defining a comment):

# Differentiate:

D(x)Sin(x)

# Expand polynomium:

Expand((1+x)^3);

# Integrate:

Integrate(x,a,b)Sin(x);

# Taylor expansion (and show the result in nice form):

Taylor(x,0,3) Exp(x)

PrettyForm(%);

# - and show in Latex format

Taylor(x,0,3) Exp(x)

TexForm(%)

D(x)Sin(x)

# Expand polynomium:

Expand((1+x)^3);

# Integrate:

Integrate(x,a,b)Sin(x);

# Taylor expansion (and show the result in nice form):

Taylor(x,0,3) Exp(x)

PrettyForm(%);

# - and show in Latex format

Taylor(x,0,3) Exp(x)

TexForm(%)

The examples from the Yacas documentation can be executed in GUYacas by pasting the code into the GUYacas script window. This is possible because of the following convention in GUYacas:

- Lines starting with "In>" are regarded as Yacas commands (and "In>" is removed before the line is sent to Yacas)
- Lines starting with "Out>" are regarded as comments (and
"Out>"
is removed before the line is copied to the output window). Recall that
lines starting with "#" are also regarded as comments in GUYacas.

In> 0+x;These code examples can be copied into the script window on GUYacas and executed directly. The result is shown on the screenshot .

Out> x;

In> x+1*y;

Out> x+y;

In> Sin(ArcSin(alpha))+Tan(ArcTan(beta));

Known issues

The Yacas help files can not be accessed directly from within GUYacas.

Miscellaneous

- Platforms: Currently, GUYacas has only been tested on Windows XP. Please let me know if you have problems on other versions of Windows.
- Credit: Credit is due to my collegue Henrik Stengaard who wrote the first version of GUYacas and introduced me to C# programming.
- Bugs: Please report bugs to me at sorenh [at] agrsci [dot]
dk

Søren Højsgaard

sorenh@math.aau.dk