Introduction to trigonometric functions
The following functions return trigonometric values. Each function has two formats that let you choose the type of angular unit you work with: degrees or radians. For example, the cos function expects an argument in radians, while cosd expects an argument in degrees.
A radian equals 180 degrees divided by pi, or roughly 57.3 degrees. (Pi equals 3.1415927, pi radians is 180 degrees.