Section: Handle-Based Graphics
  xlabel('label')
or in the alternate form
xlabel 'label'
or simply
xlabel label
Here label is a string variable.  You can also specify properties
for that label using the syntax
  xlabel('label',properties...) 
x-axis.
--> x = linspace(-1,1);
--> y = cos(2*pi*x);
--> plot(x,y,'r-');
--> xlabel('time');
which results in the following plot.
