cos
    (PHP 3, PHP 4, PHP 5)
cos -- Cosine
Description
float 
cos ( float arg )
     cos() returns the cosine of the arg
     parameter.  The arg parameter is in radians.
    
     
Example 1. cos() example 
<?php
  echo cos(M_PI); // -1
  ?>
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     See also:
     acos(),
     sin(),
     tan(), and
     deg2rad().