php.js/atan.js

Use phpjs functions as required.

module.exports=function(){ return atan.apply(exports,arguments) };

function atan(arg) {
  //  discuss at: http://phpjs.org/functions/atan/
  // original by: Onno Marsman
  //   example 1: atan(8723321.4);
  //   returns 1: 1.5707962121596615

  return Math.atan(arg);
}