Using Degrees
To supply an angle to COS in degrees, multiply the angle by PI()/180 or use the RADIANS function to convert to radians. For example, to get the COS of 60 degrees, you can use either formula below:
Explanation
The graph of cosine above visualizes the output of the function for all angles from 0 to a full rotation. Geometrically, the function returns the x-component of the point corresponding to an angle on the unit circle. Since the cosine of an angle returns a ratio, the output of the function will always be in the range [-1, 1]. Graph courtesy of wumbo.net
Dave Bruns
Hi - I’m Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.
