50 setxunit
3 setborder
90 setangle_repere
-1 9 setxrange
-3 6 setyrange
1 1 settkstep
.5 .5 setsubtkstep
1 1 setmkstep
ticks
marks
traceaxes
axesarrow
unites

/f {setxvar
#rpn#   ln(x)
} def
/f' {setxvar
#rpn#   1/x
} def
/g {setxvar
#rpn#   x
} def
gsave
   noir
   .75 setlinewidth
   continu
  0.01  8 {f} Courbe
grestore

gsave
   pointilles
rouge
   .3 setlinewidth
   [2.78 0 2.78  dup f] ligne
[ 2.78  dup f 0 1 ] ligne
   .8 setlinewidth
   noir
   
grestore


2 settailletangente
1 (f) tangente
setTimesItalic
   (e) 2.78 0 dtext