CFLib.org – Common Function Library Project

Description:
Returns a structure containing the two real roots of a polynomial in the form: ax^2 + bx + c = 0

Return Values:
Returns a structure.

Example:

<CFSET a = 1>
  <CFSET b = -3>
  <CFSET c = -4>
  <CFSET Quadratic=#Quadratic(a, b, c)#> 

  <CFOUTPUT>
  Given a = 1, b = -3, c = -4
  The first root is #Quadratic.Root1#
  The second root is #Quadratic.Root2#
  </CFOUTPUT> 

<P>
Here's the Quadratic structure:
<P>
<CFDUMP VAR="#Quadratic#">

Parameters:

Full UDF Source:

/**
 * Returns the two real roots of a polynomial in the form: ax^2 + bx + c = 0
 * 
 * @param a      Coefficient of x^2 term 
 * @param b      Coefficient of x term 
 * @param c      Constant 
 * @return Returns a structure. 
 * @author Joel Cox (jlcox@goodyear.com) 
 * @version 1, July 18, 2001 
 */
function Quadratic(a, b, c)
{
  Var mRoots = StructNew();
  Var first = 0;
  Var second = 0;
  Var denom = 2 * a;
  Var arg1 = b^2 - 4 * a * c;
  if (arg1 LT 0) {
    mRoots["Root1"] = "not real";
      mRoots["Root2"] = "not real";
  }
  else {   
      first = -b / denom;
      second = Sqr(arg1) / denom;
      mRoots["Root1"] = first + second;
      mRoots["Root2"] = first - second; 
  }
  Return mRoots;
}