3 setxyrapport
25 setxunit
7.5 setborder
90 setangle_repere
-10 10 setxrange
-20 20 setyrange
1 1 settkstep
.5 .5 setsubtkstep
2 5 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
unites
/f {setxvar
#rpn#   abs(x^2+2*x-8)-abs(x^2-9)
} def
/g {setxvar
#rpn#   -2*x^2-2*x+17
} def
/h {setxvar
#rpn#   2*x^2+2*x-17
} def
/i {setxvar
#rpn#   2*x+1
} def
/j {setxvar
#rpn#   -2*x-1
} def
gsave
   bleu
   1 setlinewidth
   continu
   {f} courbe
grestore
gsave
   rouge
   .75 setlinewidth
   dotted
   {g} courbe
grestore
gsave
   rouge
   .75 setlinewidth
   dotted
   {h} courbe
grestore
gsave
   rouge
   .75 setlinewidth
   dotted
   {i} courbe
grestore
gsave
   rouge
   .75 setlinewidth
   dotted
   {j} courbe
grestore