Source
100 setxunit
7.5 setborder
90 setangle_repere
-1 5 setxrange
-1 5 setyrange
2 1 settkstep
.5 .5 setsubtkstep
1 1 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
unites
/f {setxvar
#rpn# x^3 
} def
/g{setxvar
#rpn# x^(1/3) 
} def
/h {setxvar
  x
} def

gsave
   noir
   .75 setlinewidth
   continu
  4 neg  4 {f} Courbe
grestore
gsave
   noir
   .75 setlinewidth
   continu
  0 neg  4 {g} Courbe
grestore
gsave
   noir
   .75 setlinewidth
   mixte
 1 neg  4 {h} Courbe
grestore