30 setxunit
18 setfontsize
-1 7 setxrange
-5 7 setyrange

/f {
   ln
} def

/g {setxvar x -1 add} def

/val 3.14 2 div def

[1 1 ] {orange} Quadrillage
tracerepere
marks
gsave
   bleu
   1.75 setlinewidth
   .0001 xmax {f} Courbe
grestore
{g} courbe

<tex>
$$
   y = \ln x
$$
</tex>

3 -2 [2 dup] cctexlabel

<tex>
$$
   y = x-1
$$
</tex>
4.5 5 [2 dup] cctexlabel