5 hours later…
8:07 AM
@user why not? The explanation in the first comment seems like a reasonable reason.

4 hours later…
12:14 PM

1 hour later…
1:22 PM
@user1729 The "oldie" refer to a different case for the standard basis, which "covers" also this case (how? it would be expalined to the asker). If we would apply the same criteria for general answers which conver special cases, I suppose we should close a lot of answers on MSE.
@user1729 To be more specific wit a concrete example, isn't it this one covered from 1 million of other asnwers alredy given on MSE?

1:55 PM
@user Yes, that question probably is a duplicate. Why not take 10 or 15 minutes to see if you can find a good dupe target, rather than dash off a quick, redundant answer?
(that took less than a minute to find... given more time, I'm sure that you can find a better target)

2 hours later…
3:40 PM
@XanderHenderson I have my own idea about giving answers and contribute to the site, that's my way, I don't expect you like it but I think you should be respectful.
@XanderHenderson What I can't really understand are users which vote to close some questions as duplicate and at the same time give ansers to questions which, applying the same criteria, should be considered duplicates. I'm not saying that giving aswers is bad. I'm saying that this is a really uncorrect behaviuor. At least you are consistent in your way, as I can see.
@XanderHenderson Anyway my point here was give an answer to @user1729 and a concrete example to motivate my suggestion to vote to reopen the mentioned OP.

1 hour later…
4:45 PM

5:06 PM

5:19 PM
@user "Your way", as you put it, is in direct conflict with the intended use of the website.
> If you accept that Stack Overflow is a wiki type system, then for the same reasons that you obviously can't have five different articles about Italy on Wikipedia, Stack Overflow can't allow duplicate questions on the exact same programming problem. While there is a fair amount of code to do pre-emptive searches as people type in questions, plus many exhortations to search before you ask, with an inviting search field and button right there on the mandatory page you see before asking your ...
Jeff Atwood on April 29, 2009

As we get more and more questions in Stack Overflow, the issue of duplicate questions becomes more pressing. The odds of any question being a duplicate, however small, increases with the total number of questions in the system. So it’s worth considering: what makes a question an exact duplicate? As I see it, there are three classes of duplicate questions, from most clear to least clear.

Cut-and-paste duplicate questions. These questions are the very definition of exact duplicates; they are typically from users who willfully take the very same question and post it again. Either they’ …

@user I always believed that a canonical question should be made for such posts, however I'm not really sure how can one be made and the difficult part I believe is giving it an general context.
Also I believe this type of question appears quite frequently.

> Passively searching and reading highly ranked Stack Overflow answers as they appear in web search results is arguably the primary goal of Stack Overflow. If Stack Overflow is working like it's supposed to, 98% of programmers should get all the answers they need from reading search result pages and wouldn't need to ask or answer a single question in their entire careers. This is a good thing! Great, even!
(emphasis mine)

5:38 PM
@XanderHenderson Who "Cut-and-paste duplicate questions". I often link useful related questions and answers. Are we talking about math or coding? You can't assimilate the procees to learn math with the process to create a code. They are completely different things. learning math reqyuire interaction and the educational purpose of MSE is one of the best and useful part of the site.

5:48 PM
@Jack Why should this thread be undeleted ? Of the two non-deleted answers, one only points towards an older question with a lot of answers already, and the other is just based on the result covered in that same older question, and uses a very classical argument (limit->bounded) that almost everyone knows and is surely somewhere on the site as well. There is surely nothing new there.

The primary goal of MSE is not to "help people learn math." The primary goal is to create a useful encyclopedia, in the style of a Wiki. Duplicates hinder, rather than help, this effort.
@user If your primary desire is to "help people learn math", then I would suggest that you might be happier on Yahoo! Answers or Quora; or in a classroom. MSE is not the right place for that mission, at least not in the way that you approach it (e.g. answering every question which comes along, and not taking the time or effort to look for duplicates).

@XanderHenderson I think that the best way to reply is to copy and past here a part of the message I've received on 23.10.2019 from Robert Cartaino, Director of Community Development Stack Exchange Inc. (you can find the full massage on my page).

You mean the automatically generated message that is sent to any user who manages to accumulate 100k XP? I'm not sure what that is mean to prove...

@XanderHenderson Mr. Robert Cartaino talks not me: "Hitting a milestone like this is a great opportunity to take a step back and remember what the points are really about. It’s not just the tens of thousands of community members who took the time to upvote your posts; it’s the uncounted millions of people — yes millions — who have also learned (and will continue to learn) from what you’ve given so selflessly"
@XanderHenderson Please note the part "who have also learned (and will continue to learn) from what you’ve given so selflessly". Are you sure you are in the right place? Not me of course.

Again, I don't see the relevance of the quote, though perhaps I should have been more precise in my own language: the goal of MSE is not to help people learn math on a one-on-one basis, but to provide an encyclopedia which can help a large number of people learn math.

6:02 PM
@XanderHenderson It is mean to prove that you own point of view is respectable like mine, You don't have the truth in your hands. You can give suggestions, advices but you can't pretend to dictate your own law to others.

@user I am not trying to dictate; I am pointing out that your behaviour is contrary to the design intentions of the site, is contrary to the community standards (as agreed upon through discussion in meta), and is contrary to the good health of the site.

@XanderHenderson If thousands of community members took the time to upvote my posts it means that those posts are useful for the community. Why you state that it is not good for the health for the site? Downvoting correct answers, closing and deleting good OP and answers are, in my opinion, not good for the health of the site.

@ArnaudD. I'm afraid "nothing new" (to some people) does not justify the action of deletion. And it is very poor excuse for deletion.

6:17 PM
> If you accept that Stack Overflow is a wiki type system, then for the same reasons that you obviously can't have five different articles about Italy on Wikipedia, Stack Overflow can't allow duplicate questions on the exact same programming problem.
"Nothing new" seems like a canonical reason for deletion...

@XanderHenderson Users in this site are not programmers. Questions and problems in programming in mathematics are by no means the same. In terms of searching, they may be completely different. Your argument does not apply here.

While the quote is about programming, it is reflective of the entirety of the StackExchange network.

@XanderHenderson That is your subjective imaginary judgement. Such action explicitly excludes users from participation.

The goal is to create a Wiki; duplication hurts the health of the site (it is not desirable to have many articles on the same thing). Deleting posts which add nothing new is "as intended".
And I don't see how this is an "imaginary" judgement. I am quoting the founder of the site... I expect that he knows how he meant the site to be used better than anyone.

@XanderHenderson This point has been raised by Jyrki very often. However, it is not clear what the definition of encyclopedia is in terms of questions of MSE. Most of time what I see is "Encyclopedia"="questions 'I' like" and "Wiki"="questions that are useful to 'me' ". By such stand point, most of the low level questions in this would all be eradicated.

6:25 PM
@XanderHenderson Refer also to this from the founder. More recently I see that from the staff more increasing partecipation is greatly appreciated particularly from new users.

@Jack That is your subjective opinion. I disagree with your characterization. The problem is not one of level, but of duplication and context.
If it is the case that many of the low level questions would be closed and/or deleted, then this would be because so many of the low level questions are duplicates of each other, or are so narrow as to be essentially useless to anyone other than the asker.
@user I see nothing there which contradicts anything I've said. Some duplication can be good. But do we really need 100 questions which all ask how to find the limit of $f(x)/g(x)$, where $f$ and $g$ are both functions which limit to 0?

@XanderHenderson Yes we need if at least one new user can learn from that and be motivated to take a part in the community. Self searching for duplicates is good and must be improved but the present way to handle the issue is completely wrong.

@Jack Suppose you are a beginner in some math subject and you search here for a FAQ and find over 1000 matches. How are you supposed to judge which of those are the best answer? By organizing the dupes we can help guide students to the "best" answers, and make them easier to locate (which will decrease the chance that further dupes are posted)

6:41 PM
@BillDubuque I do not object to organize the dupes. My previous response refers to unreasonable deletion. Sorry if I have stirred things up and confused you.

@Jack Deletion is necessary in order to whittle down the thousands of answers to FAQs to a more manageable number that contains all of the possible methods, viewpoints, etc.

28 mins ago, by Jack
@ArnaudD. I'm afraid "nothing new" (to some people) does not justify the action of deletion. And it is very poor excuse for deletion.

@BillDubuque Fair voting to best questions and correct answers is the only way to select best questions and answers. Also improving duplicates organization, merging, classification and self searching are important issues. But many users come here on MSE to directly learn from other users and it will always be the case. Otherwise why don’t read a good math book instead of a page on the web?

@BillDubuque And there seems to be several posts being discussed and I was confused. One at a time.

6:54 PM
@user But up/downvoting doesn't solve the problem of massive duplication of FAQS. Already in my tags the variations of FAQs that are asked anew every semester number into the hundreds and will soon be in the thousands. If even experts can't navigate this huge maze how can we expect students to? It's no wonder they don't search now since it is often impossible to comprehend the large amount of unorganized duplicate information.

One more vote needed for: U79-1,U79-2,U79-3

7:27 PM
@Jack The help center says that "Closed questions that are of no lasting value whatsoever should be flagged and deleted.", and this Meta SE answer by an employee adds that "You delete a question when the content no longer adds anything to the site".
I'd like to point out that the employee's answer that I pointed out in my previous message explicitly mentions that not all duplicates are worth keeping, even for signaling purposes; and that the current version of that portion of the answer has been written after the often-quoted "Strangedupe" blog post.

7:56 PM
0

I'm trying to figure out how to prove that the function $$f(x)=\frac{\sin(x)}{x}$$ is bounded (without using derivatives). I can clearly see it is bounded by looking at its graph, but can't find the way to show it formally.

This is not a duplicate. And it was not closed as a duplicate.
I do not find a duplicate
And this post adds to site showing why the function is bounded over its domain.

8:18 PM
I'm wondering why OP decided to delete their post(question+answer) in this case. Should this be let deleted assuming OP wanted it gone? FWIW OP's profile is also gone.
Im retaining my vote for now, hoping to hear some opinions on it.

8:38 PM
@Nyssa There is sometimes a suspicion that a user is attempting to hide the evidence of cheating on an assignment. It doesn't look like that in this case, but that is one possibility.
The question looks fine to me, and it is generally considered inappropriate to delete a question after getting an answer. While the question (and deletion) are rather old, I don't see any reason not to vote to undelete.

@XanderHenderson I thought that too, but why would they delete it after 5 months if it's about hiding something?
Do any of you have a SDE query to check other post from an user (with deleted account)? I remember Martin linked one recently, but I can't find it right now.

@Nyssa Personally, I don't try to understand the motivations of others if those motivations have no effect on my actions.
I don't really care why the asker deleted the question; I just gave a possible motivation (which appears, to me, unlikely in this case). In any event, the question itself seems fine (if a little narrow), and I see no reason not to undelete it.
Regarding SEDE queries, I am highly inexpert. Martin is the person to ask.

@XanderHenderson Good, the only problem I see is that we need a mod/20k+ users to undelete the answer from there.

3 hours later…
11:58 PM
I will point out that deleted posts are not shown there, only the posts that still exist.