25 setxunit
7.5 setborder
90 setangle_repere
-0.5 10 setxrange
-0.5 20 setyrange
pi 1 settkstep
.5 .5 setsubtkstep
2 2 setmkstep
ticks
marks
traceaxes
axesarrow
unites
/f {setxvar
#rpn#   2*x-Sin(x)
} def
/g {setxvar
#rpn#   2*x+1
} def
gsave
   bleu
   .75 setlinewidth
   continu
  0  3 pi mul {f} Courbe
grestore
gsave
   rouge
   .75 setlinewidth
   mixte
  xmin  xmax {g} Courbe
grestore