5 \documentclass[12pt]{article}
6 \usepackage[charter]{mathdesign}
14 pair O,C,D,H,A,I,J,K,P;
21 I=cc intersectionpoint segment(O,A);
22 ce=perpendiculaire(O,A,I);
23 J=cd intersectionpoint ce;
25 C=segment(O,J) intersectionpoint cc;
26 D=segment(O,K) intersectionpoint cc;
28 trace droite(O,O+u*(1,0)) dashed evenly;
29 trace droite(O,O+u*(0,1)) dashed evenly;
31 trace cd dashed withdots;
32 drawoptions(withcolor gris);
33 trace Codelongueur(C,H,H,D,2);
34 trace segment(C,D) dashed evenly;
36 trace demidroite(A,C);
37 trace demidroite(A,D);
38 trace codeperp(O,C,A,5);
39 trace codeperp(O,D,A,5);
42 label.urt(btex Observateur etex,A);
45 drawarrow segment(H,P) withpen pencircle scaled1.5bp;
46 drawarrow segment(H,A) withpen pencircle scaled1.5bp;