# SEC

## Purpose:

Calculates the secant of any expression.

## Syntax:

SEC(val)

 val - A scalar, series or table.

## Returns:

A scalar, series, or table.

## Example:

sec(-2*pi..pi/100..2*pi);gridhv;griddot;sety(-10, 10)

displays the secant from -2π to 2π.

sec(pi)

returns -1.

## Example:

sec(-2..0.1..2)

returns a 41 point series.

## Remarks:

The secant is defined as:

for all complex z.

The function calculates in radians unless degrees are specified with the SETDEGREE function.

At or near ((2N + 1) / 2) π radians, or (2N + 1) 90 degrees, where N is any large integer, this function returns very large results or math errors.