%% PhS
%% fig_fct_convexe_03

40 setxunit
-4 6.3  setxrange
-2 5.5 setyrange

%% definition des points
/Oxg {-3.5 0} def
/Oxd {6 0} def
/h {0.8} def
/Ax {-2} def
/Ay {Ax dup mul 5 div 1 add} def
/Bx {Ax h add} def
/By {Bx dup mul 5 div 1 add} def
/Dx {4} def
/Dy {Dx dup mul 5 div 1 add} def
/Cx {Dx h sub} def
/Cy {Cx dup mul 5 div 1 add} def


/A {Ax Ay} def
/B {Bx By} def
/C {Cx Cy} def
/D {Dx Dy} def

%% parametrage de la parabole
/xdet {settvar t t} def
/ydet {settvar t dup mul 5 div 1 add} def



%% traces
continu
[A B C D Ax 0 Bx 0 Cx 0 Dx 0] points
[Oxg Oxd] ( ->) ligne



-3 4.5 settrange
{xdet} {ydet} courbeparam


/coul1 {188 255 div 128 255 div 9 255 div setrgbcolor} def
coul1



vert
pointilles
[Ax 0 A] ligne
[Bx 0 B] ligne
[Cx 0 C] ligne
[Dx 0 D] ligne


rouge
continu
[B A D C] ligne



%% texte

setTimesItalic
bleu



<tex>
$ x $
</tex>
Ax -0.6 [1.7 dup] bctexlabel


<tex>
$ x+h $
</tex>
Bx -1.2 [1.7 dup] bctexlabel


<tex>
$ x'-h $
</tex>
Cx -1.2 [1.7 dup] bctexlabel


<tex>
$ x' $
</tex>
Dx -0.6 [1.7 dup] bctexlabel