%% PhS
%% fig_Rch06_fin_poly_courbes_param_02

40 setxunit
-2 6  setxrange
-4 2 setyrange


%% parametrage de la parabole
/xdet {
1 dict begin
	/t exch def
	t
end
	} def


/ydet {
1 dict begin
	/t exch def
	t dup mul 5 div neg
end
	} def


/xpdet {
1 dict begin
	/t exch def
	 2
end} def


/ypdet {
1 dict begin
	/t exch def
	t 2 mul 5 div neg 2 mul
end
	} def


	
%% symetrie par rapport a un point
/symcentr { %% Ax Ay x y
4 dict begin
	/y exch def
	/x exch def
	/Ay exch def
	/Ax exch def
	gsave
	Ax 2 mul x sub
	Ay 2 mul y sub
	grestore
end
	} def
	



%% definition des points

/M0x {1 xdet} def
/M0y {1 ydet} def
/M0vx {1 xpdet} def
/M0vy {1 ypdet} def


/xdetsym {
1 dict begin
	/t exch def
	M0x M0y t xdet t ydet symcentr pop
end
	} def


/ydetsym {
1 dict begin
	/t exch def
	M0x M0y t xdet t ydet symcentr exch pop
end
	} def



%% definition d'une couleur
/coul1 {120 255 div 70 255 div 9 255 div setrgbcolor} def
coul1



%% traces
continu
[M0x M0y] points



vert
1 4 settrange
{xdet} {ydet} courbeparam
-3 1 settrange
{xdetsym} {ydetsym} courbeparam


rouge
continu
[M0x M0y M0x M0y M0vx M0vy addv] (->) ligne
%%[M0x M0y M0x M0y M0vx neg M0vy neg addv] (->) ligne



%% texte

setTimesItalic
coul1 

<tex>
$ M(t_0) $
</tex>
M0x -0.3 add M0y -0.25 add [1.7 dup] dctexlabel