1.1.6 `gnuplot.plot_function'
-----------------------------

gnuplot.gnuplot(F|proc=P)
     ::  ask the `gnuplot' server to draw a graph of F

RETURN
     Void

P
     Number

F
     Polynomial or a list of polynomials

   * ask the `gnuplot' server to draw a graph of F

     [290] gnuplot.plot_function((x+sin(x))^2);
     0
     [291] gnuplot.plot_function([x,x^2,x^3]);
     0

Reference
     `gnuplot.to_gnuplot_format'

