most recent 30 from http://mathoverflow.net 2013-05-19T03:52:27Z http://mathoverflow.net/feeds/question/66302 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/66302/reason-why-the-even-root-of-a-number-always-positive nmehta 2011-05-28T18:01:40Z 2011-05-28T18:01:40Z

<p>So here goes the stupidest question on this site. I know that the definition of the even root of a number goes something like this: When n is an even natural number and a is a real number, then the nth root of a is a number b such that b^a = n. For all b >= 0. So for example the square root of 4 is either +2 or -2. But according to this definition only +2 is considered as the 2nd root of 4. Is there a reason for this?</p>