-2 2 setxrange -1.5 1.5 setyrange 50 setxunit 8 -8 6 SetCamPos 0 0 0 SetCamView qplanxy -10 10 setxrange3d -3 3 setyrange3d /f { 1 dict begin /t exch def #rpn# Cos (3*t) #rpn# Sin (3*t) #rpn# t/8 end } def 0 pi 3 mul {f} CourbeR3 #tex# $$f (t) = \big(\cos 3t, \sin 3t,t/8\big)$$ 0 ymin [1.6 dup] uctexlabel