%% auteur : gh 100 setxunit -2.5 2.5 setxrange -1.5 1.5 setyrange /O {0 0} def /a 2 def /b 1 def /c {a 2 exp b 2 exp sub sqrt} def /F {c neg 0} def /F' {c 0} def /Dx {a 2 exp c div neg 0} def /Dx' {a 2 exp c div 0} def /D {Dx Dx 0 1 addv} def /D' {Dx' Dx' 0 1 addv} def /X {Cos a mul} def /Y {Sin b mul} def traceaxes axesarrow 16 setfontsize setTimesItalic (O) O dltext 2 setlinewidth rouge 0 pi 2 mul settrange {X} {Y} courbeparam 1.2 setlinewidth /t {pi 3 div} def /M {t dup X Y} def /N {t Cos a mul t Sin a mul} def noir setTimesItalic (M) M urtext (N) N urtext [F F'] points setTimesItalic (F) F dctext (F') F' dctext vert /I {a t Cos div 0} def M I droite /v {t Sin b mul a t Cos div a t Cos mul sub} def /P {M v subv} def M P droite bleu F M (-) line F' M (-) line 0.7 setlinewidth /arrowangle -5 store F M P 0.2 (=) tripointarc P M F' 0.2 (=) tripointarc