What are cosines?

Some articles on cosines, cosine:

Law Of Cosines - Law of Cosines in Non-Euclidean Geometry
... A version of the law of cosines also holds in non-Euclidean geometry ... C with opposite sides a, b, c then the spherical law of cosines asserts that each of the following relationships hold In hyperbolic geometry, a pair of equations are collectively known as the hyperbolic ... sinh and cosh are the hyperbolic sine and cosine, and the second is Like in Euclidean geometry, one can use the law of cosines to determine the angles A, B, C from the knowledge of the sides a, b, c ...
Jamshīd Al-Kāshī - Mathematics - Law of Cosines
... In French, the law of cosines is named Théorème d'Al-Kashi (Theorem of Al-Kashi), as al-Kashi was the first to provide an explicit statement of the law of cosines ...
Spherical Law Of Cosines
... In spherical trigonometry, the law of cosines (also called the cosine rule for sides) is a theorem relating the sides and angles of spherical triangles, analogous to the ordinary law of cosines ... to w), and the angle of the corner opposite c is C, then the (first) spherical law of cosines states Since this is a unit sphere, the lengths a, b, and c are simply equal to the angles (in radians ... then and one obtains the spherical analogue of the Pythagorean theorem A variation on the law of cosines, the second spherical law of cosines, (also called the ...
Hyperbolic Law Of Cosines
... In hyperbolic geometry, the law of cosines is a pair of theorems relating the sides and angles of triangles on a hyperbolic plane, analogous to the planar law of cosines from ... Christian Houzel (page 8) indicates that the hyperbolic law of cosines implies the angle of parallelism in the case of an ideal hyperbolic triangle When α = 0, that is when the ...
Cosec(x) - Properties and Applications - Law of Cosines
... The law of cosines (also known as the cosine formula or cosine rule) is an extension of the Pythagorean theorem or equivalently, In this formula the angle at C is opposite to the side c ... The law of cosines can be used to determine a side of a triangle if two sides and the angle between them are known ... It can also be used to find the cosines of an angle (and consequently the angles themselves) if the lengths of all the sides are known ...