Foci Meaning: Definition, Examples, and Translations
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foci
[ˈfoʊ.saɪ ]
Definition
mathematics, science
Foci are specific points used in the context of conic sections in mathematics. In geometry, they refer to the fixed points related to the shape of an ellipse or hyperbola. For an ellipse, there are two foci, which are located along the major axis. The distance from any point on the ellipse to the two foci has a constant sum, which is a unique characteristic of ellipses. In physics, the term can also refer to points from which light or heat emanates, such as in the case of a lens or mirror.
Synonyms
Examples of usage
- The distance from any point on the ellipse to the two foci is constant.
- In his study of light, he examined the foci of the lens.
- The foci of the hyperbola can be calculated using the equation of the curve.
Translations
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Origin of 'foci'
The word 'focus' originates from the Latin word 'focus', meaning 'hearth, fireplace, or center'. Originally used in reference to a physical hearth where heat and fire are centric, it evolved in mathematical terms during the 17th century to describe the loci of conic sections. The plural form 'foci' was adopted to indicate multiple points, particularly in the study of ellipses and hyperbolas. This term became essential in both mathematics and physics, representing crucial points that define the geometry of conics and the study of light phenomena. Over time, its applications have expanded beyond traditional fields, encompassing various scientific and theoretical domains.