This common proof, as well as many closely related proofs - are already presented in many prior answers here, e.g. see the inked dupes and the posts linked there. Please search for answers before asking questions. $\ \ $
Although to some extent, if you check out the post that I linked in my comment, you might see various ways to search and you can be able to see for yourself which of them are usable for MO: How to search on this site?
I would disagree with "Google is a better search engine for MathOverflow than MathOverflow's built-in search" as a blanket statement covering all possible cases. I do certainly use Google quite often. At the same time, on SE sites I often restrict the search to some combination of tags. There are certainly many various ways how to search - which of them works better might depend on the situation. (As far as searching goes, Mathematics has some advantages over MO, for several reasons.) — Martin Sleziakyesterday
Is this the post you are looking for—? math.stackexchange.com/a/4538371 (I searched for 0.091767* user:1714. The star operator is a wildcard, and the user operator searches within your posts.) Oh wait, is it that you wanted other posts containing this number? Then the search 0.091767* might help. (But this latter search only brings up your post. Searching for 0.0917* brings up two more, not sure how related.) — The Amplitwist7 hours ago
Just wanted to find any q&A containing the numerical constant $0.091767$. ('ve used this constant (with some more digits) in an answer of mine. Pure text-search does not find matches, so maybe one must search for this numbers as a math expression. Now approach0 finds many mathces, but no relation to the digits of my number... now no more option? — Gottfried Helms7 hours ago
Approach0
Searching for a specific formula is often rather difficult. A tool which is very suitable for this is the Approach0 search engine.
Some basic information can be found in Guide for New Users (which contains also animations of some examples). If you want to know more about the project, ...
> In addition to the built-in searchbar (which has some more powerful options), you may also want to consider using the advice given in the question How to search on this site?. The math-aware search engine approach0 may also be useful.
@XanderHenderson I am a bit torn whether it is better to link directly to Approach0 or maybe to this answer. (The latter has an advantage that it has also some examples.)
One thing I would consider in favor of closing as a duplicate - it is possible to leave a comment explaining how the duplicate was found (and thus helping the user to learn that they should search before asking and also how to search).
Approach0
Searching for a specific formula is often rather difficult. A tool which is very suitable for this is the Approach0 search engine.
Some basic information can be found in Guide for New Users (which contains also animations of some examples). If you want to know more about the project, ...
@NicolasChabanovsky hello! Thanks for coming back to this and sorry for the delay. I think the simplest would be to link the faq mentioned by @MartinSleziak in the help center. This one https://math.meta.stackexchange.com/questions/29265/how-to-search-on-this-site
@NicolasChabanovsky hello! Thanks for coming back to this and sorry for the delay. I think the simplest would be to link the faq mentioned by @MartinSleziak in the help center. This one math.meta.stackexchange.com/questions/29265/…
Hi everyone! Could you please tell me what is the community's current stand on this question? As I can see, you have already created a meta post about external search options and there is an answer that contains a paragraph that might be added to the /help/searching. Could you please tell me if I understand you correctly? (Btw, I started a conversation in the chat, please feel free to ping there.) — Nicolas Chabanovsky ♦24 mins ago
The loop rules in the Comprehensive Rules do not cover these situations. However, a recently added section of the Magic Tournament Rules does address the scenarios in this question. Of course, the Magic Tournament Rules are not binding on casual "kitchen table" games, but it is reasonable to inte...
I'll repeat my suggestion that sometimes it might be useful to do a bit of searching and you might find some similar problems on the site: How to search on this site?
Some time ago, we discussed that this link could be added into help center: How to search on this site? Are there plans among moderators to request doing this?