350 setwidth
-2 5 setxrange
-.3 3 setyrange

/f {
   setxvar
   x 1 add dup mul
   x neg Exp mul
} def

quadrillage
.7 setlinewidth
tracerepere
-1 0 {f} Hachcourbe

1.2 setlinewidth
{f} courbe

-1 xmark
1 xmark
1 ymark


14 setfontsize
setTimesItalic
   (O) O dltext
   (C) 2.5 dup f uctext
   (x) xmax 0 (-5 0) dltext
   (y) 0 ymax (-2 -5) dltext