60 setxunit
7.5 setborder
90 setangle_repere
-2.5 2.5 setxrange
-0.5 3 setyrange
/quadrillagegray 0.5 def
0.25 setquadrillagexstep
0.25 setquadrillageystep
quadrillage
0.5 0.5 settkstep
.25 .25 setsubtkstep
0.5 0.5 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
unites
/f {setxvar
#rpn#   (x^4)/4-x^2+1.5
} def
gsave
   bleu
   .75 setlinewidth
   continu
 2.5 neg 2.5  {f} Courbe
grestore