Trident curve explained

In mathematics, a trident curve (also trident of Newton or parabola of Descartes) is any member of the family of curves that have the formula:

xy+ax3+bx2+cx=d

Trident curves are cubic plane curves with an ordinary double point in the real projective plane at x = 0, y = 1, z = 0; if we substitute x =  and y =  into the equation of the trident curve, we get

ax3+bx2z+cxz2+xz=dz3,

which has an ordinary double point at the origin. Trident curves are therefore rational plane algebraic curves of genus zero.

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