60 setxunit
7.5 setborder
90 setangle_repere
-1.3 1.3 setxrange
-1.3 1.3 setyrange
1 1 settkstep
.5 .5 setsubtkstep
1 1 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
1.75 setlinewidth
continu
bleu
/X {settvar
#rpn#   Sin(t)*Sin(2*t) + Cos(t)*Cos(2*t)/2
} def
/Y {settvar
#rpn#   Sin(2*t)*Cos(t)/2 - Cos(2*t)*Sin(t)
} def
  pi 2 div  3 pi mul 2 div {X} {Y} Courbeparam
pointilles
  3 pi mul 2 div  5 pi mul 2 div {X} {Y} Courbeparam
noir
continu
/XX {settvar 
#rpn# Cos(t)
} def
/YY {settvar 
#rpn# Sin(t)
} def
0.75 setlinewidth
 0 2 pi mul {XX} {YY} Courbeparam