Mathematical pogram Octave wasn't thoughtful as program, which can supply comercial Matlab, but it was propose as user-friendly program for writing university textbook about proposal chemical reactor. Although was this plane, there was using in many next universities and in training chemical engineering in university in Texas. Mathematical department this university, was using to learning differential equation and linear algebra. Author opf this sofftware (John W. Eaton) are hope, that Octave will efficient tool for ambitious calculations. Everyone can share this software with next rules of GNU general public licence. You can contribute to do octave more useful - writing and supplying additional functions, report bugs... As illustration contribution to projecy Octave, there are graphic add-on - octaviz and Octplot, which there are described.