%% PhS %% fig_fct_convexe_01 40 setxunit -4.5 7 setxrange -2.3 5.5 setyrange %% definition des points /O {0 0} def /Oxg {-2.5 0} def /Oxd {7 0} def /Oyb{0 -3.3} def /Oyh {0 5.5} def /Ax {0.4} def /Ay {Ax -2.3 add dup mul 5 div 1 add} def /Bx {2.5} def /By {Bx -2.3 add dup mul 5 div 1 add} def /Bsy {Bx Ax sub Cx Ax sub div Cy Ay sub mul Ay add} def /Cx {6} def /Cy {Cx -2.3 add dup mul 5 div 1 add} def /A {Ax Ay} def /B {Bx By} def /Bs {Bx Bsy} def /C {Cx Cy} def %% parametrage de la parabole /xdet {settvar t t} def /ydet {settvar t -2.3 add dup mul 5 div 1 add} def %% traces continu [O A B Bs C Ax 0 Bx 0 Cx 0 0 Ay 0 Bsy 0 Cy ] points [Oxg Oxd] ( ->) ligne [Oyb Oyh] ( ->) ligne -1.5 6.5 settrange {xdet} {ydet} courbeparam /coul1 {188 255 div 128 255 div 9 255 div setrgbcolor} def coul1 vert pointilles [0 Ay A Ax 0] ligne [0 Bsy Bs Bx 0] ligne [0 Cy C Cx 0] ligne rouge continu [A C] ligne %% texte setTimesItalic bleu (O) O dltext bleu $ x $ Ax -0.6 [1.6 dup] bctexlabel $ \lambda x+(1-\lambda)x' $ Bx -0.6 [1.6 dup] bctexlabel $ x' $ Cx -0.6 [1.6 dup] bctexlabel $ f(x) $ -0.2 Ay [1.6 dup] cltexlabel $ \lambda f(x)+(1-\lambda)f(x') $ -0.2 Bsy [1.6 dup] cltexlabel $ f(x') $ -0.2 Cy [1.6 dup] cltexlabel