Talk:square root

The (square) root of a number is always positive. However, the equation x2 = 4 has two solutions, 2 and -2, or stated differently, &radic;4 and -&radic;4 \Mike


 * This is not quite the usage I learned when I got my math degree.


 * There are a couple of things going on. A number is a square root of another number iff its square is the number in question.  That is, -2 and 2 are both square roots of 4.


 * On the other hand, the square root function, being a function, must choose one or the other possibility, so by convention it is defined to be non-negative. That is, the result of applying the square root function to a non-negative number is another non-negative number.


 * However, this is a fine point. In general usage, even among mathemeticians, square root means positive square root.  But the usages a square root and the positive square root are used when there may be ambiguity.


 * I'm not going to update the definition right now pending wider consensus, particularly since Wikipedia takes the "postitive" view. -dmh 17:58, 19 Apr 2004 (UTC)~