%% auteur : 

60 setxunit
7.5 setborder
90 setangle_repere
-1 7 setxrange
-1 3 setyrange
traceaxes
axesarrow
marks


/f {setxvar
    2.2
} def
gsave
   noir
   2 setlinewidth
   continu
 0 7   {f} Courbe
grestore

/fillstyle {hachure} def
1.5 4.5 {f} Fillcourbe 

/A0 {1.5 0} def
/A1 {4.5  0} def
/B0 {1.5 2.2} def
/B1 {4.5 2.2} def
[A0 B0] ligne
[A1 B1] ligne

<tex>
  $a$
</tex>
A0 [1.5 1.5]dctexlabel

<tex>
  $b$
</tex>
A1 [1.5 1.5]dctexlabel

<latex>
  $\mathcal{C}_f$
</latex>
6 2.7 [1.5 1.5]dctexlabel


<tex>
  $y=k$
</tex>
6 2.2 [1.5 1.5]dctexlabel


<tex>
  $k$
</tex>
0 2.2 [1.5 1.5] cltexlabel