100 setxunit 7.5 setborder 90 setangle_repere -2 1 setxrange -0.5 1.5 setyrange 1 1 settkstep .5 .5 setsubtkstep 0.5 0.5 setmkstep ticks subticks marks traceaxes axesarrow /R {settvar #rpn# (1+Sin(t))/(sqrt(3)+Cos(t)) } def 0 2 pi mul settrange gsave .75 setlinewidth continu bleu (R) courbepolar grestore