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:
“Why is it so difficult—so degradingly difficult—to bring the notion of Time into mental focus and keep it there for inspection? What an effort, what fumbling, what irritating fatigue!”
—Vladimir Nabokov (1899–1977)