%% PhS gh
%% 

%% Èchelle et Ètendue de l'image
60 setxunit
-1 6  setxrange
-2 4  setyrange


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  DANGER !! Il ne faut pas utiliser de variables
%%  DANGER !! qui commence par les lettres :
%%  DANGER !! xmin, xmax, ymin et ymax...
%%  DANGER !! Utiliser x_min, y_min...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%




%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% procÈdures
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%% on donne ici x(t)
/xdet {
1 dict begin
	/t exch def
	t
end
	} def

%% on donne ici y(t)
/ydet {
1 dict begin
	/t exch def
	t dup mul dup mul -0.05 mul t dup mul 0.4 mul add t -0.3 mul add 1.5 add
end
	} def


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% dÈfinitions des couleurs
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

/coul1 {120 255 div 70 255 div 9 255 div setrgbcolor} def



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% tracÈs
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% tracÈ des axes et du point Origine
1 setlinewidth
15 setfontsize
noir
continu
traceaxes
marks
tracerepere



2 setlinewidth
coul1
continu
-2 2.5 settrange
{xdet 2.5 add} {ydet} courbeparam


/fillstyle {hachure} def

1 setlinewidth


noir
continu
[0.5 0 0.5 -2 ydet] (-) ligne
[5 0 5 2.5 ydet] (-) ligne


[0.5 0 0.5 1.2 -2.5 add ydet 1.8 1.2 -2.5 add ydet 1.8 0] polygone*
[1.8 0 1.8 2.4 -2.5 add ydet 3.5 2.4 -2.5 add ydet 3.5 0] polygone*
[3.5 0 3.5 4.1 -2.5 add ydet 4.2 4.1 -2.5 add ydet 4.2 0] polygone*
[4.2 0 4.2 4.7 -2.5 add ydet 5 4.7 -2.5 add ydet 5 0] polygone*

rouge
pointilles
[1.2 dup -2.5 add ydet 1.2 -0.4] (-) ligne
[2.4 dup -2.5 add ydet 2.4 -0.4] (-) ligne
[4.1 dup -2.5 add ydet 4.1 -0.4] (-) ligne
[4.7 dup -2.5 add ydet 4.7 -0.4] (-) ligne


vert
[0.5 0 0.5 -1.1] (-) ligne
[1.8 0 1.8 -1.1] (-) ligne
[3.5 0 3.5 -1.1] (-) ligne
[4.2 0 4.2 -1.1] (-) ligne
[5 0 5 -1.1] (-) ligne



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% texte
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
setTimesItalic



vert
<latex>
$a_0=a$
</latex>
0.5 -1.3 [1.8 dup] cctexlabel

<latex>
$a_1$
</latex>
1.8 -1.3 [1.8 dup] cctexlabel

<latex>
$a_2$
</latex>
3.5 -1.3 [1.8 dup] cctexlabel

<latex>
$a_3$
</latex>
4.2 -1.3 [1.8 dup] cctexlabel


<latex>
$a_4=b$
</latex>
5 -1.3 [1.8 dup] cctexlabel

rouge
<latex>
$\xi_0$
</latex>
1.2 -0.6 [1.8 dup] cctexlabel

<latex>
$\xi_1$
</latex>
2.1 -0.6 [1.8 dup] cctexlabel

<latex>
$\xi_2$
</latex>
4.1 -0.6 [1.8 dup] cctexlabel

<latex>
$\xi_3$
</latex>
4.7 -0.6 [1.8 dup] cctexlabel