Source
%% PhS

%% fig_conique_17

35 setxunit
-8 8  setxrange
-6.5 6.5 setyrange

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%% procédures

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/bddroite {
8 dict begin
/kd exch def
/kg exch def
/By exch def
/Bx exch def
/B {Bx By} def
/Ay exch def
/Ax exch def
/A {Ax Ay} def
gsave
[A A B vecteur kg mulv addv A A B vecteur kd mulv addv] ligne
grestore
end
} def

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%% definition d'une couleur

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/coul1 {120 255 div 70 255 div 9 255 div setrgbcolor} def

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%% definition des points

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/a {4} def
/c {7} def
/b {c c mul a a mul sub sqrt} def
/e {c a div} def
/Kx {a e div} def
/K {Kx neg 0} def
/K+ {K 0 6 addv} def
/K- {K 0 -6 addv} def
/Kp {Kx 0} def
/Kp+ {Kp 0 6 addv} def
/Kp- {Kp 0 -6 addv} def
/O {0 0} def
/F {c neg 0} def
/Fp {c 0} def
/S1 {a neg 0} def
/S2 {a 0} def
/B {0 b} def

/xdet {settvar t t mul b b mul div 1 add sqrt a mul} def
/ydet {settvar t} def

/Mx {b 0.6 mul xdet} def
/My {b 0.6 mul ydet} def
/M {Mx My} def
/H {M Kp Kp+ orthoproj} def

/bissec {F M Fp bissectrice} def
/T {bissec Kp Kp+ interdroite} def
/U {bissec M perp Kp Kp+ interdroite} def

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%% traces

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1 setlinewidth
[O F Fp S1 S2 B K Kp M T H] points
F Fp -0.05 1.05 bddroite

2 setlinewidth
coul1
b -1.2 mul b 1.2 mul settrange
{xdet} {ydet} courbeparam

1 setlinewidth
vert
[K+ K-] ligne
[Kp+ Kp-] ligne
M H Kp angledroit
pointilles
[M H] ligne

bleu
continu
[F M Fp T] ligne
M Fp T angledroit
F M T 0.5 (=) tripointarc
T M Fp 0.7 (=) tripointarc

orange
continu
M T -0.4 1.3 bddroite
M U -1.3 1.8 bddroite

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%% texte

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setTimesItalic
noir
(O) O [1.5 dup] dltext
(F) F [1.5 dup] drtext
(F') Fp [1.5 dup] drtext
(B) B [1.5 dup] ultext

<latex>
$S_1$
</latex>
S1 [1.3 dup] dltexlabel

<latex>
$S_2$
</latex>
S2 [1.3 dup] drtexlabel

noir
(M) M -0.2 0.2 addv [1.5 dup] uctext

vert
(K) K [1.5 dup] dltext
(K') Kp [1.5 dup] drtext
(H) H [1.5 dup] cltext

<latex>
$\mathcal{D}$
</latex>
K 0 -5 addv [1.5 dup] dltexlabel

<latex>
$\mathcal{D}'$
</latex>
Kp 0 -5 addv [1.5 dup] drtexlabel

coul1
(T) T [1.5 dup] cltext