In geometry, Wallis's conical edge is a ruled surface given by the parametric equations
x = v cos u , y = v sin u , z = c a 2 − b 2 cos 2 u {\displaystyle x=v\cos u,\quad y=v\sin u,\quad z=c{\sqrt {a^{2}-b^{2}\cos ^{2}u}}}
where a, b and c are constants.
Wallis's conical edge is also a kind of right conoid. It is named after the English mathematician John Wallis, who was one of the first to use Cartesian methods to study conic sections.
See also Plücker's conoid Ruled surface Right conoid
References
A. Gray, E. Abbena, S. Salamon, Modern differential geometry of curves and surfaces with Mathematica, 3rd ed. Boca Raton, Florida:CRC Press, 2006. [1] (ISBN 978-1-58488-448-4)
External links Wallis's Conical Edge from MathWorld.