25 setxunit
7.5 setborder
90 setangle_repere
-4 5 setxrange
-4 5 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#   -(1/2)*x^2+x+(7/2)
} def
/g {setxvar
#rpn#   3*x^2-12*x+12
} def
gsave
   bleu
   0.75 setlinewidth
   continu
   {f} courbe
grestore
gsave
   rouge
   0.75 setlinewidth
   continu
  xmin  .01 neg {g} Courbe
  .01  xmax {g} Courbe
grestore


#latex#${\mathcal{C}_g}$
3.5 4.25 [2 2] crtexlabel


#latex#${\mathcal{C}_f}$
3.5 -3.25 [2 2] crtexlabel