about TeX

Here is a page discussing how to write mathematical expressions in LaTeX: http://en.wikibooks.org/wiki/LaTeX http://www.math.umbc.edu/~rouben/beamer/     A Beamer tutorial http://www.andy-roberts.net/misc/latex/   LaTeX tutorial...

about Sage

Here is what Wikipedia says about the free Sage software: http://en.wikipedia.org/wiki/Sage_(mathematics_software) You can use an online version of  Sage for free at http://www.sagenb.org/ sagenb Here is the Sage documentation front page, with links to tutorials,...

about Octave

Octave is a free program for doing math computations, especially ones related to linear algebra.  You can experiment with parts of Octave online at the following site: http://lavica.fesb.hr/octave/octave-on-line_en.php Some hints about using Octave can be found at...