40 setxunit 7.5 setborder 90 setangle_repere -3 3 setxrange -4 4 setyrange 1 1 settkstep .5 .5 setsubtkstep 2 2 setmkstep ticks subticks marks traceaxes axesarrow unites /f {setxvar #rpn# x^2 } def gsave bleu 1 setlinewidth continu {f} courbe grestore 1 setlinewidth continu bleu /X {settvar #rpn# Cos (t) } def /Y {settvar #rpn# -2+Sin (t) } def 0 2 pi mul {X} {Y} Courbeparam /t1 {setxvar #rpn# 2*sqrt(4+sqrt(13))*x-(4+sqrt(13)) } def gsave rouge .75 setlinewidth pointilles {t1} courbe grestore /t2 {setxvar #rpn# 2*sqrt(4-sqrt(13))*x-(4-sqrt(13)) } def gsave rouge .75 setlinewidth pointilles {t2} courbe grestore/t3 {setxvar #rpn# 2*(-sqrt(4+sqrt(13)))*x-(4+sqrt(13)) } def gsave rouge .75 setlinewidth pointilles {t3} courbe grestore/t4 {setxvar #rpn# 2*(-sqrt(4-sqrt(13)))*x-(4-sqrt(13)) } def gsave rouge .75 setlinewidth pointilles {t4} courbe grestore