Haversine formula

The haversine formula determines the great-circle distance between two points on a sphere given their latitudes and longitudes, and it is important in navigation as a special case of a more general result in spherical trigonometry called the law of haversines. The first table of haversine values in English was published by James Andrew in 1805, though the mathematician Florian Cajori credited an earlier use to Jose de Mendoza y Rios in 1801, and the term haversine itself was coined in 1835 by James Inman as a contraction of half-versed sine. Before the advent of computers, writing the formula in terms of the haversine function was convenient because it eliminated certain divisions and multiplications by factors of two, which is why tables of haversine values and logarithms appeared in nineteenth and early twentieth century navigation and trigonometry texts. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/