Fibonacci - Golden Ratio

In mathematics, the Fibonacci numbers or Fibonacci series or Fibonacci sequence are the numbers in the following integer sequence: 0, 1, 1,2, 3, 5, 8, 13, 21, 34, 55, 89, 144 ...

I have always done the one with recursion (or iteration). But mathematics says we could do it with the Golden Ratio ..

	var phi = (1 + Math.sqrt(5)) / 2;
	var fib_gr = function (n) {
	return Math.floor((Math.pow(phi, n) / Math.sqrt(5)) + (1 / 2));
	};
	for (var i = 1; i < 20; ++i) {
	console.log(i, '->', fib_gr(i));
	}
	var fib_recursion = function (n) {
	if (n === 0 || n === 1) {
	return n;
	}
	return fib_recursion(n-1) + fib_recursion(n-2);
	};
	for (var i = 1; i < 20; ++i) {
	console.log(i, '->', fib_recursion(i));
	}

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