What is the meaning cosine value?

Answer 1

The cosine, in mathematics, is a function. It originated many thousands of years ago in calculations involving triangles. In a right triangle, the cosine of one of the acute angles is the length of the opposite side divided by the length of the hypotenuse. As mathematics advanced, the definition of the cosine function was extended to include a larger variety of inputs. The unit circle is a circle on a graph centered at the origin of radius one. If one side of an angle is the positive x axis and the vertex is the origin, then the other side of the angle crosses the unit circle at a point whose x-coordinate is the sine and whose y-coordinate is the cosine of that angle. Even more generally, if x is anything that can be added an multiplied (a complex number, a square matrix, etc.) then cos(x) is defined by the infinite series 1 - x2 / 2! + x4/4! - ... .