Wikipedia:Articles for deletion/Square root of 5 (2nd nomination)


 * The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review).  No further edits should be made to this page.

The result was keep. Liz Read! Talk! 02:14, 24 June 2022 (UTC)

Square root of 5
AfDs for this article:


 * – ( View AfD View log | edits since nomination)

As noted in WT:AFD, having multiple articles for individual square roots is "more than enough". SQRT(2) is special, if for no other reason that it's the first one. The others, not so much. I'll be nominating Square root of 3, Square root of 5, Square root of 6, and Square root of 7. The same argument applies to them all, but I'll make them distinct AfDs because bundled AfDs so often become train wrecks. -- RoySmith (talk) 00:26, 17 June 2022 (UTC)
 * Note: This discussion has been included in the list of Mathematics-related deletion discussions. -- RoySmith (talk) 00:26, 17 June 2022 (UTC)
 * Note: Previous deletion discussion from long ago is at Articles for deletion/Square root of 5. Dicklyon (talk) 01:30, 17 June 2022 (UTC)
 * Keep. We definitely shouldn't have articles on more than a very small number of these square roots (Maybe only $$\sqrt2$$, $$\sqrt3$$, and $$\sqrt5$$), but I think $$\sqrt5$$ has enough properties to be independently notable. If it were only its appearance in the formula for the golden ratio, we could redirect there, but its appearance in basic geometric shapes having nothing to do with the golden ratio, such as the diagonal length in a $$1\times 2$$ rectangle, and as the tight constant in Hurwitz's theorem (number theory), give it enough for independent notability. —David Eppstein (talk) 00:40, 17 June 2022 (UTC)
 * Keep per David, especially given Hurwitz's theorem. — Ceso femmuin mbolgaig mbung, mellohi! (投稿) 04:30, 17 June 2022 (UTC)
 * Keep. Perhaps not as clear-cut as square root of 3, but as explained above (and even in the 2007 AfD), its significance for the golden ratio, Fibonacci numbers, regular pentagon, and Hurwitz's theorem appear to give it enough coverage to pass GNG. , for example, notwithstanding the references already present in the article. ComplexRational (talk) 14:56, 17 June 2022 (UTC)
 * Keep per others above as well as the prior AfD discussion. There is clearly a substantial literature concerning special properties of this number. I do not understand the basis for suggesting deletion. Newyorkbrad (talk) 15:42, 17 June 2022 (UTC)
 * Strong Keep. For all the above reasons stated, and simply because it is intrinsically connected to the golden ratio. In fact, given a sequence of Fibonacci and Lucas numbers, we can discern that $$\lim_{n\to\infty} \frac{L_n}{F_n}=\sqrt{5}.$$ It is such a profoundly powerful simple equation for $$\sqrt5$$, which can be replicated within a rectangle with simple measurements, making it an essential construction. It's not as important as the $$\sqrt2$$, but it is possibly the second most important square root of interest, alongside the square root of three given its universal trigonometric properties. This article is important, lets please keep it; thank you. Radlrb (talk) 10:37, 21 June 2022 (UTC)
 * Note that in the first deletion nomination discussion, nobody was able to point out any reference that would support notability, of the 6 references at that time. Now, there are 14 references, and a somewhat better suggestion of notability of the square root of 5 as a special number.  The arguments there that this number was "inherently notable" were weak, but now I think we're in a better place.  Similarly, square roots of a few other small integers are pretty well sourced now.  I'll admit that my satirical Square root of 4 article does not have quite the same support in sources, even though I found some good ones.  For square roots of 2, 3, 6, and 7, there are pretty good sources.  Higher than that, I don't think so.  So this is where we draw the line.  I don't think an article on the square root of 8 or 9 or 11 would fly; 10 maybe.  Dicklyon (talk) 05:06, 22 June 2022 (UTC)
 * I don't imagine Square root of -1 would fly either, and I could be induced to make the identical argument for Square root of 0. -- RoySmith (talk) 14:00, 22 June 2022 (UTC)
 * Square root of -1 is pretty important and notable, but it has other names. Square root of 1 and square root of 0 are too trivial, since they are just side effects of multiplicative and additive identities, which are well covered elsewhere. Dicklyon (talk) 16:58, 22 June 2022 (UTC)
 * Actually, the square root of minus-1 is one of the very most important numbers for us to have an article about, for both intrinsic and historical reasons, and of course we do have such an article; it is found under the title imaginary unit, to which "square root of -1" is a redirect. The square root of 0 is of course 0 itself, and we obviously have an important article about that number; there is no need for a separate "square root of" article where the "of" number is a perfect square and so the root itself is an integer. Newyorkbrad (talk) 17:03, 22 June 2022 (UTC)
 * Yes, I am fully aware of that. I was just having some pun.  Hence my use of "imagine".  I'll leave it to you folks to find the other puns I embedded. -- RoySmith (talk) 17:08, 22 June 2022 (UTC)
 * Keep because of the connections with golden ratio and for other reasons. Robert McClenon (talk) 16:54, 22 June 2022 (UTC)
 * Keep Relatively important in mathematics. 68.198.188.106 (talk) 22:26, 23 June 2022 (UTC)


 * The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.