如何得到一个数的双平方根

Question

I need to get a double square root of a number but my codes won't work:

function doubleSquareRootOf(num) {
  return num * num * num;
}

var output = doubleSquareRootOf(121);
console.log(output); // --> it must return 22 but its displaying 1771561

Any idea?

Answer 1

尝试 sqrt * 2 而不是 num

return Math.sqrt(num)*2;

Answer 2

math.sqrt(math.sqrt(number)) -> 这是一个数字的双平方根