octave-3.2.2:25> plot(x,sin(x));
warning: sin: some elements in list of return values are undefined
error: __plt2__: invalid data for plotting
error: called from:
error:   /usr/share/octave/3.2.2/m/plot/__plt2__.m at line 72, column 7
error:   /usr/share/octave/3.2.2/m/plot/__plt__.m at line 79, column 10
error:   /usr/share/octave/3.2.2/m/plot/plot.m at line 186, column 5
octave-3.2.2:25>