Catalan trisectrix | l'Hôpital cubic

x(t) = a (1 - 3 t^2) y(t) = a t (3 - t^2)

(a - x) (8 a + x)^2 = 27 a y^2

r(θ) = a sec^3(θ/3)

algebraic | cubic | parametric | polar | trisectrix

d = 3