--- /dev/null
+var $ = require('../internals/export');
+var log1p = require('../internals/math-log1p');
+
+var nativeAcosh = Math.acosh;
+var log = Math.log;
+var sqrt = Math.sqrt;
+var LN2 = Math.LN2;
+
+var FORCED = !nativeAcosh
+ // V8 bug: https://code.google.com/p/v8/issues/detail?id=3509
+ || Math.floor(nativeAcosh(Number.MAX_VALUE)) != 710
+ // Tor Browser bug: Math.acosh(Infinity) -> NaN
+ || nativeAcosh(Infinity) != Infinity;
+
+// `Math.acosh` method
+// https://tc39.github.io/ecma262/#sec-math.acosh
+$({ target: 'Math', stat: true, forced: FORCED }, {
+ acosh: function acosh(x) {
+ return (x = +x) < 1 ? NaN : x > 94906265.62425156
+ ? log(x) + LN2
+ : log1p(x - 1 + sqrt(x - 1) * sqrt(x + 1));
+ }
+});