calcul – Vertical tangent folium of Descartes

So, for the folium of descartes, there is a horizontal and vertical tagnet at $ (0,0) $.

Using a parametric equation, $ x = 3t / (1 + t ^ 3) $ and $ y = 3t ^ 2 / (1 + t ^ 3) $.

Asymptotic horizontal I understand. But vertical asymptote?

There is a vertical asymptote, when $ dx / dt = $ 0but $ dx / dt $ is equal to $ 0 only when $ t = (1/2) ^. $ 333. This gives another point where a vertical asymptote is present.

So, how can I calculate that there is a vertical asymptote at (0,0) using these parametric equations?