Focus (geometry)
In geometry, the foci ( /ˈfoʊsaɪ/; singular focus) are a pair of special points with reference to which any of a variety of curves is constructed. For example, foci can be used in defining conic sections, the four types of which are the circle, ellipse, parabola, and hyperbola. In addition, foci are used to define the Cassini oval and the Cartesian oval.
Read more about Focus (geometry): Cartesian and Cassini Ovals, Generalization, Confocal Curves
Famous quotes containing the word focus:
“Carlyle is not a seer, but a brave looker-on and reviewer; not the most free and catholic observer of men and events, for they are likely to find him preoccupied, but unexpectedly free and catholic when they fall within the focus of his lens.”
—Henry David Thoreau (1817–1862)