25 setxunit
7.5 setborder
90 setangle_repere
-3.5 8.5 setxrange
-6 6 setyrange
/quadrillagegray 0.4 def
1 setquadrillagexstep
1 setquadrillageystep
quadrillage
1 1 settkstep
.5 .5 setsubtkstep
2 2 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
unites
/f {setxvar
#rpn#   1.46875 + 1.96875*x -0.46875*x^2 + 0.03125*x^3
} def
/g {setxvar
#rpn#   x
} def
gsave
   noir
   .75 setlinewidth
   continu
   {f} courbe
grestore
7.8 settailletangente
-1 {f} tangente