18 setxunit
7.5 setborder
90 setangle_repere
-6 8 setxrange
-5 6 setyrange
1 1 settkstep
.5 .5 setsubtkstep
2 2 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
unites
/f {setxvar
   5 x 1 sub div  2 add
} def
/g {setxvar
   2
} def
gsave
   noir
   1.75 setlinewidth
   continu
  xmin  0.9 {f} Courbe
  1.1  xmax {f} Courbe
grestore
gsave
   rouge
   .75 setlinewidth
   pointilles
   {g} courbe
1 -1 1 1 droite
grestore