Présentation de courbes_param_02.jps

/syracuse/bbgraf/albums/coniques/courbes_param_02.jpg
%% 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