I ask excuse me because I was doing other things, like a paper, and I could not post since 4, April.
Now, I finished the paper, and other things.
Let's continue talking about the plot(.) function.
The command for create a new window is scf(), it creates a blank window.
If you have a used window but you want to clear it, so you use the command clf();
Those commands (scf() and clf()) have no arguments.
The scf() is utile for show many graphs simultaneously, like the following example.
The script is following, too:
-->x = 1:100;
-->w1 = %pi/3;
-->y1 = cos(w1*x);
-->w2 = %pi/7;
-->y2 = cos(w2*x);
-->scf(); plot(x, y2);
The next posts will present how to change the colors and styles of the graphs, and how to put labels on the graphs.