php.js/acosh.js

Use phpjs functions as required.

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

function acosh(arg) {
  //  discuss at: http://phpjs.org/functions/acosh/
  // original by: Onno Marsman
  //   example 1: acosh(8723321.4);
  //   returns 1: 16.674657798418625

  return Math.log(arg + Math.sqrt(arg * arg - 1));
}