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

  The absolute value of number must be less than 2^27

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

trigonometry_triangleThe secant is the reciprocal of the cosine. Therefore, for the right-angle 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:  

    \[    sec(A) = \frac 1{cos(A)} = \frac h{b}    \]

See Wikipedia for more information on trigonometric ratios.