Paraboloid

In mathematics, a paraboloid is a quadric, a type of surface in three dimensions, described by the equation:

<math>

\left( \frac{x}{a} \right) ^2 + \left( \frac{y}{b} \right) ^2 + 2z = 0 </math> (elliptic paraboloid),

or

<math>

\left( \frac{x}{a} \right) ^2 - \left( \frac{y}{b} \right) ^2 + 2z = 0 </math> (hyperbolic paraboloid).