title: future value calculation not returning expected result
body: <p>have the following FV function</p>
  
  <pre><code>private static function fv($r,$n,$p,$pv=0)
  {
      $sum = $pv;
      for ( $i=0;$i&lt;$n;$i++ ) {
       $sum += ($sum * $r) + $p;
      }
      return $sum;
  }
  </code></pre>
  
  <p>These are the values I'm passing in:</p>
  
  <p>0.0067
  444
  1834.58</p>
  
  <p>This is the value I'm expecting from my deskcheck: 4983453.613
  This is what I'm getting from my method: 5036155.12</p>
  
  <p>Driving me nuts. I've tried a bunch of other functions on-line; none of them work!</p>