60 setxunit
7.5 setborder
90 setangle_repere
-0.25 3.2 setxrange
-1 1.5 setyrange
0.7859 1 settkstep
.5 .5 setsubtkstep
0.78539 1 setmkstep
ticks
ymarks
traceaxes
axesarrow
unites
/f {setxvar
#rpn#   (Sin(x))^4
} def
/g {setxvar
#rpn#   -(Sin(x))^4
} def
gsave
   noir
   .75 setlinewidth
   continu
 0 pi  {f} Courbe
grestore
gsave
   noir
   .75 setlinewidth
   continu
 0 pi  {g} Courbe
grestore
gsave
   jaune
   continu
   /hstep 4 store
   /hangle 45 store
   {f} {g} hachcourbes
grestore