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:
“While the focus in the landscape of Old World cities was commonly government structures, churches, or the residences of rulers, the landscape and the skyline of American cities have boasted their hotels, department stores, office buildings, apartments, and skyscrapers. In this grandeur, Americans have expressed their Booster Pride, their hopes for visitors and new settlers, and customers, for thriving commerce and industry.”
—Daniel J. Boorstin (b. 1914)