Using the Excel COS Function
SummaryThe Excel COS function returns the cosine of a given angle.
The number argument is required in the COS function. This is the angle, in radians, for which you want to find the cosine.
Usage NotesCOS returns the cosine of an angle that is given in radians. If your angle is in degrees, multiply by PI()/180 or use the RADIANS function to convert to radians.
For example, if you wanted to find the COS of 80 degrees you could do either of the following: