Source
40 setxunit
7.5 setborder
90 setangle_repere
-5 5 setxrange
-4 7 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#   x^2
} def
/g {setxvar
#rpn#   1/x
} def
/h {setxvar
#rpn#   1/x^2
} def
gsave
   bleu
   .75 setlinewidth
   continu
   {f} courbe
grestore
gsave
   rouge
   .75 setlinewidth
   continu
 xmin .01 neg  {g} Courbe
 .01 xmax  {g} Courbe
grestore
gsave
   vert
   .75 setlinewidth
   continu
   {h} courbe
grestore
   

  rouge

<tex>
$y={1\over x}$
</tex>
-4 -3 [1.5 1.5] urtexlabel

bleu

<tex>
$y=x^2$
</tex>
3 6 [1.5 1.5] drtexlabel 

   vert

<tex>
$y={1\over x^2}$
</tex>
-4 2 [1.5 1.5] drtexlabel