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:
![](https://upload.wikimedia.org/wikipedia/commons/thumb/f/fd/Newton_trident.svg/300px-Newton_trident.svg.png)
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 = x/z and y = 1/z into the equation of the trident curve, we get
![](https://upload.wikimedia.org/wikipedia/commons/thumb/0/03/Newton_trident_y%3Dinf.svg/300px-Newton_trident_y%3Dinf.svg.png)
which has an ordinary double point at the origin. Trident curves are therefore rational plane algebraic curves of genus zero.
References
- Lawrence, J. Dennis (1972). A Catalog of Special Plane Curves. Dover Publications. p. 110. ISBN 0-486-60288-5.
External links
- O'Connor, John J.; Robertson, Edmund F., "Trident of Newton", MacTutor History of Mathematics Archive, University of St Andrews