PHP Software Source Code Math Library Logarithm Base Equation

AJ PHP Software Source Code Math Library
Logarithm Base

float log_base ( number y, number x)

Description:

log_base returns the base(b) of the logarithm given y and x in the following equation.

Source Code:

function log_base ($x, $y)
{
  //variable and initializations
  $the_result = 0.0;
  $temp01     = 0.0;

  //take the base 10 logarithm of y and divide by x
  $temp01 = log10($y) / $x;

  //calculate the result
  $the_result = pow(10.0, $temp01);

  //return the value
  return $the_result;
}

Example:

<?
include ("ajmath.php");

$x = 2.0;
$y = 5.4;

$the_base = log_base ($x, $y);

echo "x = $x<br>";
echo "y = $y<br>";
echo "the_base = $the_base<br>";
?>

Run Example

array average	solve for the average of an array
factorial integer	solve for the factorial of an integer
log base	solve for the base of the logarithm function

References - Books:

Max A. Sobel, Nobert Lerner. 1991. Precalculus Mathematics. Prentice Hall.