2.5 setxyrapport
50 setxunit
7.5 setborder
90 setangle_repere
-1 8 setxrange
-5 5 setyrange
1 1 settkstep
.5 .5 setsubtkstep
2 2 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
1. setlinewidth
continu
bleu
/X {settvar
#rpn#   t^3/(3*t+1)
} def
/Y {settvar
#rpn#   3*t^2/(3*t+1)
} def
  5 neg  0.34 neg {X} {Y} Courbeparam
  0.32 neg  5 {X} {Y} Courbeparam
noir
1.75 setlinewidth
[0 0 0 2] (->) ligne
/A {0 .33} def
/B {1 -8.67} def
.75 setlinewidth
A B droite