Hyperboloid

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

<math>{x^2 \over a^2} + {y^2 \over b^2} - {z^2 \over c^2}=1</math>

(hyperboloid of one sheet),

or

<math>{x^2 \over a^2} + {y^2 \over b^2} - {z^2 \over c^2}=-1</math>

(hyperboloid of two sheets).