function sec( x ) {
	return 1.0 / cos( x );
}
Evaluates the secant of a number.

@param {number} x - input value (in radians)
@returns {number} secant

@example
var v = sec( 0.0 );
// returns 1.0

@example
var v = sec( 3.141592653589793/2.0 );
// returns 16331239353195370.0

@example
var v = sec( -3.141592653589793/3.0 );
// returns ~1.9999999999999996

@example
var v = sec( 3.141592653589793/3.0 );
// returns ~1.9999999999999996

@example
var v = sec( NaN );
// returns NaN