Cos is the cosine function of a right triangle in trigonometry. Cos function is the ratio of the adjacent side and hypotenuse. If we have a right triangle and α is the angle between adjacent side and hypotenuse, then as per the cos function, we can write
Cos α = Adjacent Side/Hypotenuse
The value of cos is derived for different values of angles such as 0°, 30°, 45°, 60°, 90° and more are given in this table.