; Demo of multiple functions in one graph.

 a = 31
 b = 9
 f(x) := SIN(x)
 g(x) := COS(x)
 h(x) := -SIN(x)
 i(x) := -COS(x)
 PLOT f,g,h,i
 SHOW a, b
 TITLE "sine and cosine"
 SUBTITLE "waveforms"
 GBOUNDS 0,2
 XLABEL "x axis"
 YLABEL "y axis"
 LEGEND