cosine

sine
tangent

definition

Cosine, sine, and tangent are three fundamental trigonometric functions that relate the angles of a right triangle to the lengths of its sides.

The cosine (cos) of an angle is defined as the ratio of the adjacent side to the hypotenuse. In other words, it is the length of the adjacent side divided by the length of the hypotenuse.

The sine (sin) of an angle is defined as the ratio of the opposite side to the hypotenuse. In other words, it is the length of the opposite side divided by the length of the hypotenuse.

The tangent (tan) of an angle is defined as the ratio of the opposite side to the adjacent side. In other words, it is the length of the opposite side divided by the length of the adjacent side.

These three functions are used extensively in trigonometry and other fields such as engineering, physics, and mathematics.