I HAVE OBTAINED THE FOLLOWING MESSAGE: octave-3.0.3:14> plot (t,x) sh: gnuplot: command not found sh: gnuplot: command not found error: you must have gnuplot installed to display graphics; if you have gnuplot installed in a non-standard location, see the 'gnuplot_binary' function HAW I CAN RESOUD THE PROBLEM. THANK YOU RAFFAELE COTZA