Sine and cosine are fundamental functions in trigonometry, a branch of mathematics that deals with the relationships between the angles and sides of triangles. They are particularly important in the study of right triangles and periodic phenomena. ### Sine (sin) The sine of an angle (usually measured in degrees or radians) in a right triangle is defined as the ratio of the length of the opposite side to the length of the hypotenuse.
New to topics? Read the docs here!