Related Functions:
The SEC function returns the secant of an angle.
 This function was introduced in Excel 2013 and so is not available in earlier versions.
Syntax
=SEC(number)
Arguments
Argument  Description  

number  The number argument is the angle, in radians, for which you want the secant

Examples
A  B  C  

1  Formula  Result  Notes 
2  =SEC(0.7853982)  1.4140748  Returns the secant of a 45 degree angle 
3  =SEC(RADIANS(45))  1.414213562  Returns the secant of a 45 degree angle 
4  =SEC(PI()/4)  1.414213562  Returns the secant of a 45 degree angle 
Note: If the angle is in degrees, you need to be convert it to radians before supplying it to the SEC function. You can convert it, using the RADIANS function: =RADIANS(degrees)
Common Function Error(s)
Problem  What went wrong 

#VALUE!  Occurs if the supplied number argument is not recognized as a numeric value 
#NUM!  Occurs if the supplied number argument is less than 2^27 or is greater than 2^27 
The secant is the reciprocal of the cosine. Therefore, for the rightangle triangle at right, the secant of angle A is equal to the hypotenuse (h), divided by the adjacent side (b). For the angle at right, secant is calculated as:
See Wikipedia for more information on trigonometric ratios.