All right, this is actually a very old piece of imperative knowledge for computing square roots, it's attributed to Heron of Alexandria, although I believe that the Babylonians are suspected of knowing it beforehand.

好，这是一个很古老的,关于计算平方根的程序性知识，是亚历山大的海伦提出的，不过我怀疑在那之前,巴比伦人就已经猜想过了。

麻省理工公开课 - 计算机科学及编程导论课程节选

Don't worry about how came about, Heron found this out.

别担心这是怎么来的，海伦发现了这个规律。

麻省理工公开课 - 计算机科学及编程导论课程节选