CFLib.org – Common Function Library Project

Description:
Returns the inverse hyperbolic secant of a value. All angles are expressed in radians.

Return Values:
Returns a numeric value or string.

Example:

<CFSET x=1>
<CFSET y=2>
<CFOUTPUT>
Given x=#x#:<BR>
Given y=#y#<BR>
Asech(x)=#Asech(x)#<BR>
Asech(y)=#Asech(y)#<BR>
</CFOUTPUT>

Parameters:

Full UDF Source:

<cfscript>
/**
 * Returns the inverse hyperbolic secant of a value.
 * 
 * @param x 	 0 < x <= 1 
 * @return Returns a numeric value or string. 
 * @author Rob Brooks-Bilson (&#114;&#98;&#105;&#108;&#115;&#64;&#97;&#109;&#107;&#111;&#114;&#46;&#99;&#111;&#109;) 
 * @version 1, October 16, 2001 
 */
function Asech(x){
  if (x lte 0)
    return "undefined";
  else 
    if (x gt 1)
      return "undefined";
  else
    return Log((Sqr(-x*x+1)+1)/x);
}
</cfscript>