autocrop
-.2 5 setxrange
-.5 1.2 setyrange

0 5 setxrange
0 1.2 setyrange

50 setxunit
100 setyunit

/lambda 1 def
/f {
   lambda mul neg Exp 
} def

.6 setlinewidth
gsave
   mixte
   {pop 1} courbe
grestore

1 setlinewidth 
0 xmax {f} Courbe
gsave
   pointilles
   0 xmax {f neg 1 add} Courbe
grestore

traceaxes
axesarrow
0 xmark
1 ymark

setTimesItalic
   (y) 0 ymax drtext
   (t) xmax 0 dltext

<tex>
$y = R (t)$
</tex>
2 dup f urtexlabel

<tex>
$y = F (t)$
</tex>
2 dup f neg 1 add drtexlabel