title: Mistake in javascript with NaN in an array
body: <p>When I execute this function in javascript, I get a NaN result. It seems quite ilogical beacuse the arrays employed in this operation are all numerical and are shown properly when I do so with a Alert(); I left the code here for your supervision:</p>
  
  <pre><code>function calculation_errors(){      
      arr_error_P_t2=new Array();
      for(var i=0;i&lt;arr_P_t1.length;i++){
          var K=new Number(arr_K_t1[i]);
          var P=new Number(arr_P_t1[i]);      
          arr_error_P_t2[i]=(Math.sqrt(1+Math.pow(m_t2,2)))*(Math.sqrt((Math.pow(1/K,2)+(Math.pow(1/P,2)))));
      }
      alert(arr_error_P_t2.join('\n'));
  }
  </code></pre>