Maxima 20 6 19 http://maxima.sourceforge.net/ download Sourceforge download page http://sourceforge.net/project/showfiles.php?group_id= 4933 maxima X xmaxima & Windows xmaxima wxMaxima describe(string) string ? string describe(string) apropos(string) string example(topic) topic ; $ ......; ......$ % %o1 %% block %th(i) i /* ... */ _ %i1 __ : a:3 a 3 := f(x):=sin(x) :: fundef(func) func kill(v) v r