%% 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
continu
bleu
[F F'] points
D droite
D' droite
setTimesItalic
(F) F dctext
(F') F' dctext
(D) Dx 0 1.5 subv urtext
(D') Dx' 0 1.5 subv urtext
noir
setTimesItalic
(a) a 0 urtext
(b) 0 b urtext
(c) F' uctext
(-c) F uctext
$$
-{a^2 \over c}
$$
Dx [1 1] drtexlabel
$$
{a^2 \over c}
$$
Dx' [1 1] dltexlabel