Descartes Welcome to Descartes, one of the cheapest mathematics software on the planet. Rene Descartes, the guy at bottom left, gave his name to Cartesian co-ordinates (x y co-ordinates), Cartesian graphs and Cartesian geometry - all relating to ideas that this application is concerned with. As well as being cheap, Descartes is very environmentally friendly. It uses only recycled electrons, and bio-degrades completely after use. Don't walk away, Rene..