Documentation/Calc Functions/SEC

Function name:
SEC

Category:
Mathematical

Summary:
Calculates the trigonometric secant (sec) of an angle expressed in radians.

Syntax:
SEC(Number)

Returns:
Returns a number that is the trigonometric secant of the specified angle. The value returned is a real number x, such that x ≤ -1 or x ≥ 1 (x cannot lie in the range (-1, 1)).

Arguments:
Number is a real number, or a reference to a cell containing that number, that is the angle in radians whose trigonometric secant is to be calculated.


 * If Number is non-numeric, then SEC reports a #VALUE! error.

Additional details:
If your angle is expressed in degrees, either multiply by PI/180 or use the RADIANS function to convert to radians.

The formula for the trigonometric secant of x is:

$$\sec(x)~=~\frac{1}{\cos(x)}$$

Mathematically, the secant of any odd multiple of π/2, i.e. {......-3π/2, -π/2, π/2, 3π/2.....} is undefined. However, because of the inherent inaccuracy in representing &pi; numerically, SEC does not report errors for arguments close to these values. You should be aware that SEC will return large positive or negative results for odd multiples of π/2.

The figure below illustrates the function SEC.

Related LibreOffice functions:
COS

COT

CSC

SIN

TAN

ODF standard:
Section 6.16.52, part 2

Equivalent Excel functions:
SEC