I don't think that any of the tags here are appropriate. Any ideas on correct tagging?

Question I suggest to reopen HERE.

Why? Nothing was changed since it was closed. If you want something reopened, it is probably worthwhile to justify why.

@MikeMiller Indeed I don't understand the closure in this case. It seems a good question to me. The asker has shown all his effort and was on the good track for the resolution.

I invite the users here to reconsider that. Thanks

On the topic of context, just posting your attempt is the least one can do, and it is focused on far too much.

In any case, as a matter of principle I do not get involved in bad faith requests.

Have a good night.

@MikeMiller Sorry I don't get your point. If you think that the question is good you can vote to reopen otherwise it will remain closed. Bye

Most likely the close process started when the question looked like this: math.stackexchange.com/revisions/3028851/4 Revision 5 is the first revision where the OP added a bit more text.

But I see that the case is considered closed, so it probably is not worth talking about it.

@MartinSleziak Yes indeed at first the question was not so good but it was improved by the asker. Isn't it a case eligible for reopening?

@gimusi Sorry, my impression was that you are not interested in discussing it anymore, which is why I left.

I am not sure whether it is just your style talking. But when I see "Bye" at the end of the message, it makes an impression that you do not want to hear more from the user you responded to.

@MartinSleziak I'm always intereted in discussion, Mike told me "Good night".

And I replied to that.

Fair enough, but this was definitely not first comment (or chat message) from you that sounded like this.

In any case regarding: 3028851 Show that $g(x)=[\frac1x]\sin x$ has a limit in $x=0$.

@MartinSleziak Really that should be a misunderstaing, always appy to have discussion and exchange in opinions.

Here is the last revision by the OP before closure - revision 9; one more edit from you came before closing.

But of course I don't want to waste your time. I've just posed to your attention an OP which I suppose eligible for reopening.

Personally, I would consider the question in that form sufficient context. The only question is whether this was genuinely something added by the OP, or whether the OP simply copied it from your answer.

@MartinSleziak But the final question is now ok? or there are still some lackness which justify to keep it closed?

@TheSimpliFire Up for deletion.

@MartinSleziak I think it is genuine since also after the asker wrote the final (or almost the final) version of the question, he/she didn't undestand how to conlude with that. I think that in this case it was only a problem related to a lackness in write down the question properly.

@MartinSleziak If he/she was interested just to a solution why should he/she have to spend time in editing the question?

It seems that the timestamp of your answer is 18:39. The first revision where I see the inequality is Revision 7 with the timestamp 19:21.

I really think that this user is in good faith and should be supported for that.

Was this mentioned in some earlier revision which I missed. Was the inequality mentioned in some comments?

At the very least the OP added something. Even though in revision 7 it was something already present in an answer (hint-answer) at the time, at least the limit in revision 8 seems not to be copied elsewhere.

And the fact that the OP at least tried to edit the post counts for something. I voted to reopen. We will see what other users think - and how the question fares in the reopen review uqeue: math.stackexchange.com/review/reopen/1116160

@MartinSleziak Yes the inequality was given by some hints or almost complete solutions in that or different forms but things were very confused. At the end I think that this user is aimed to act in a proper way.

If we do not support neither these case I think that there is no hope to improve thongs here.

@MartinSleziak Thanks for your analisys, really appreciative.

BTW did somebody check whether the question is not a duplicate?

@MartinSleziak No I don't, that's could be a different point.

I've searched a bit and did not find a duplicate - of course, it's possible that somebody has better luck when searching.

@MartinSleziak Thanks a lot for your constructive effort on that and more in general to make that a better place! You are one of my heros of course. Even I'm sure our ideas don't match! Bye

(if needed I'm still there for a while)

Regarding user21820's comment on your answer - you need $\sin x\ge0$ in those inequalities.

Of course, that's ok if $x$ is close enough to zero (and positive).

I am sure that anybody experienced enough with limits will understand, but still it might be probably worth mentioning this.

@MartinSleziak Yes indeed it seems really clear to me from the context, anyway I've updated that. Thanks for the advice

@gimusi I think you are right. I have voted to reopen it.

@amWhy All gone.

@JoseCarlosSantos Thanks to have take into consideration that. Really appreciative from you. I also need to apologize with you for some recent discussion. I was wrong the way I used to express my thoughts even if I confirm that I would appreciate a consistent way to act especially when dealing with closure and deletion. Sorry for my faults. Bye

@user21820 Great!

PSQs for deletion: 1, 2, 3.

4, 5, 6.

More PSQs: 7, 8, 9.

The smallest distance is dx. cough

Why is 1.124993839 so close to 1.125??

I would like to nominate this for reopening.

The OP has added a lot of context and work he tried. Including a very nice bit which should probably allow to answer with a hint.

@DRF I am not going to vote to reopen that question, though I also would not vote to reclose it were it to be opened. I really don't feel like "Here's what I tried..." is very good context. It is kind of the bare minimum level of context. In this case, I don't find the question interesting enough bother with reopening (it is a really standard exercise---Imma go look for a dupe target).

@XanderHenderson Fair enough. Though I do feel like that's moving the goalposts pretty far. He has added info about what he tried, what he knows and what he would like to use. Unless I'm missing something a Hint to try and use an automorphism to change to the case he knows would be sufficient.

@DRF How am I moving the goalposts? I've pretty consistently said that attempts are very poor context.

There are others who may disagree.

But I think that I have been pretty consistent in my stance.

@XanderHenderson Sorry I might have projected on you in that case.

;)

@XanderHenderson I'm really still trying to get a good feel for what is understood as acceptable and what's not. I'm onboard with PSQ's are bad, but I don't think I quite understand the nuances.

@DRF Different people have different opinions.

Exactly that. So the same question would can reopened/closed depending on who reviews it.

There are some things that are generally agreed, but people will differ in what they consider sufficient context.

Exactly this.

I don't like what I parse as the demanding tone in the comments.

Since I recognize that I am likely on the extreme end of the spectrum of opinions, I tend not to weigh in on questions like this one, where I can understand the point of view of others, but simply disagree. ;)

@MikeMiller That might simply be a problem stemming from the fact that the asker is not a native English speaker...?

@MikeMiller Yes I agree with that, it rubs me the wrong way too, but as Xander says I think it's likely non-native speaker that creates that. He does use please he just doesn't know how to use modals etc.

Seems plausible.

@XanderHenderson There are enough people that vote to reopen that I do not feel it is worth my energy to contribute in almost all circumstances. I think the problem of overzealous closing is less important than the problem of underzealous closing.

They can both be problems, but I have finite energy.

Essentially consider his comment. The things that are making the tone demanding is a missing "could" and some qualification of "provide answer". Same sentence "Please could you review it and try and answer." sounds much better but is a lot more complex linguistically.

I wonder if there should be a closure reason "homework problem/PSQ" The provide more context one is really quite weaselly.

@DRF Yeah, you're right. Anyway, it was just an unrelated comment on my part.

Not relevant to whether or not I think the question should be closed.

I would delete if it were not many moons late.

@DRF There used to be a close reason specifically about homework. You can find wording for example here.

And on meta you can probably find when it was abandoned.

And recently the "missing context" close reason was reworded a bit: chat.stackexchange.com/transcript/64952/2018/12/5 (I have to admit that I did not follow the discussion about the rewording too closely.)

Wow, that is a fantastic close reason.

Here is discussion perhaps in proximity to its removal.

It has been noted before that physics.se has a very strict "No Homework" policy. I wish that the culture here would allow that to happen.

I think the lack of ability to say very explicitly "This is a PSQ. We do not want PSQs." is unfortunate.

@MartinSleziak I must second @MikeMiller 's opinion that is an awesome closure reason.

I guess we have a limited number of close reasons? And it's "This or no context?"

Both are good to have.

Before somebody tells us of that we should stick to the topic of this room - which is discussing stuff like closure, reopening, etc. of specific question on main - perhaps discussion about choice of close reason would be more suitable elsewhere, maybe Math Meta Chat?

@XanderHenderson I'm curious what you mean by "really standard exercise", because it took me a while to find an elegant but systematic method to solve all such acute angle questions without numerical computation. As you know, I'm much more lenient when non-negligible effort is shown, but I'd also like to see your method if you have thought about it.

@user21820 Wouldn't an shift of the point to the origin along with the formula the OP provides in the third paragraph work?

@DRF You're right; I missed that...

@user21820 Maybe it isn't a really standard exercise? I thought it was...

@user21820 Note: I have no clue if the formula the OP provides is correct.

@DRF It's basically what happens when you apply half my method to that simple case; dropping the perpendicular to one plane gives you the normal vector that can be extracted directly from the coefficients of the equation, and then projecting it onto the normal vector to the other plane gives the answer.

@XanderHenderson Given DRF's comment, maybe it is just me being silly. I tend to miss simpler solutions once I can see a good-enough solution.

@user21820 Would you add that as a Hint to you answer maybe? That way the OP can see how to get to it I think.

@DRF Done.

@user21820 Thank you.:) Also good point on adding the argument about rigidity. Didn't really occur to me.

This is most definitely a dupe. Anyone want to help me find a good candidate as target, @MartinSleziak, @MartinR, and any else who'd like to practice searching?

@amWhy Maybe we could try in the searching chatroom?

@epimorphic I got your message. Thanks! Yes, I'll have to make sure I take screenshots of states of affairs!

@JoséCarlosSantos What tab refresher and screen catcher are you using? Curious.

None of the close reasons strictly apply. :\

The question displays a lack of research and is a poor question.

Or did you write a private script along with a tab refresher, for capturing and holding incoming questions to the review queue for late answers (and/or any all other review queues)?

But it is about math.

And there is context. And it is clear what the issue is.

@XanderHenderson "This leaves me puzzled. Websites I've seen give the expansion of the sum as ... (No citation of web URLs (plural due to the claim)), I do think it lacks sufficient context.

@amWhy Perhaps. I left a custom close message, in any case.

It seems it all boiled down to the question: "What is $0!$" where the OP assumed it to be zero, when in fact it is $1$ as you point out.

But the OP clearly didn't ask that, because they thought they knew 0! = 0. Kind of an X-Y problem, actually.

@XanderHenderson Yeah, thank gosh we have that option!!

Yup. X-Y problem. Thank goodness for custom close reasons. Agree 100%. ;)

@amWhy My tab refresher is called “tab auto refresh”. I don't use a screen catcher.

I ask this, @JoséCarlosSantos, because you benefit excessively (more than any other user) from handling late answers after other users have already handled them. The last three late answers I handled, you subsequently handled too, though they need only be handled once.

I started to use a tab refresher only after I noticed that you often handled late answers after other people had dealt with the same answers. As you did today with this answer, six hours after someone else dealt with it.

@JoséCarlosSantos Well I certainly don't match the number of posts you handle after others do, nor the number of late answers as you somehow manage to handle. So don't deflect the concern: it is you who is dominating the queue, and though you don't work and can afford to spend every waking minute here, that alone can't explain it.

@amWhy math.stackexchange.com/review/late-answers/history

And how is it that all three questions I handled today were immediately subsequently handled by you, @JoséCarlosSantos? That seems a bit unsettling to me. Just how much experience do you have computing?

@amWhy Not as much as I wish I had.

The asker of this question has asked some very poor questions, given their rep. Keep your eyes out.

@AlexanderGruber Please note this user's pattern of poor questions. I linked only one above, because I do not want to target the user, but a quick review of their questions, at least recently, seems to reveal consistently poor posts.

@amWhy yeah some of those are notable

Just wanted to bring it to your attention, (and other mods).

Several are an interesting case actually... bad multiple choice homework questions, but have attempts included

@AlexanderGruber Yes, indeed. Just quality of questions seems a bit incommensurate with reputation.

yes-- they have been around a while.

it'd be interesting to hear opinions of the regulars of this room on that issue in the abstract, actually. What do you think about questions which are very dry and homework-y, but do include attempts or thoughts that are legitimate (in the sense that they are not just obligatory blurbs, though they may be as boring and unmotivated as the question is)?

o/ @JyrkiLahtonen Hello!

IMHO this "gem" is in dire need of delete votes. Unfortunately it is also a dupe of this. We cannot directly delete a dupe target. IIRC it may help to get the referring question deleted first?

Hi @amWhy.

@JyrkiLahtonen The referring question has two delete votes.. Let's hope for a third.

Thanks, @amWhy :-)

@JyrkiLahtonen That's "Thanks," :P

Gone, both of them!

@AlexanderGruber I am probably at one extreme of the spectrum, but I really don't think that an attempt at a problem does very much of anything at all to add context. At best, it is a way of preempting XY problems.

I think that my objection stems from the idea that if a question is to be useful to many people, then the context should explain why it will be useful. An "attempt" just says "this is where I got stuck!", and so such context will make the question useful only to others that got stuck at the same step.

But such things are hard to search for, so the question itself becomes useless to almost everyone.

I also really don't like proof-verification questions, for many of the same reasons.

Also, not all "attempts" are created equal. I am able to appreciate sincere attempts to grapple with the material, but I think there are too many "cursory, or "obligatory blurbs", which you aptly refer to, @AlexanderGruber, that are mechanical in nature, and don't really engage or interact with the question at hand.

@amWhy (Thanks, @Did, for your help in deleting these).

@AlexanderGruber I'm not a regular but will weigh in anyway assuming that you're quite able to disregard if you wish. While I understand Xander's point of view I think it ends up very strongly limiting the questions that can be asked. Making it very hard for beginners to ask "good" questions as other than "I came across the problem here and this is what I tried" they rarely are able to say much more.

Having said that as I noted a while back in Math Meta it's not obvious that the format of this site (Q&A) is really great for teaching beginners anything anyway. To me it actually seems unlikely it's any good for that.

@DRF Most students who are up to date on their reading, attending lectures, and regularly doing homework assignments are able to say something significant with respect to their efforts toward a typical exercise. To state an exercise, and make rather cursory attempts that really don't address the question, or run circles around it, to me, is game playing. So while a sincere engaging attempt may reveal sincere involvelment and count as context, just because scribbles pretend to attempt an

answer, doesn't make it a sincere attempt to engage with material. Too many students come to MSE asking homework problems and perhaps faking attempts after they've fallen behind in coursework and haven't much of a clue as to what is being asked.

@amWhy I'm more skeptical than you regarding this. But at the same time I do agree that a lot of the questions I've seen fail even a very basic laugh test. I just remember some of the students I've taught that came from average or subpar high schools and made it into UW with a goal to try some STEM field (biology/chemistry/rarely engineering) and many of them even if they tried quite hard had incredible problems.

@DRF UW: University of Washington? Wisconsin? Just Curious...

@amWhy Wisconsin

@DRF That's my home state!

I teach in the UW system, too.

@amWhy I loved my time there even if it had some personal issues. :) Very nice place, great university and great state. I was in Madison and the city was extremely friendly in all the good ways.

Madison is wonderful! Not necessarily representative of the whole state, but awesome.

@amWhy Heh it's probably very far from representative from what I could tell. It's a blue island in a sea of red no?

We got to travel around a bit so we saw some of the rest of the state and I enjoyed all of it. Though of course I didn't get a feeling for the people of any of the other parts of the state. 2 day stays don't tell you much.:)

@DRF Probably at the time, indeed. Madison is very blue. Historically, Wisconsin has a very blue past, but for at least a generation, suburbs have been very red, yes. The county I grew up in is probably the "reddest" of all WI counties, to my shigrin! But, WI managed to elect a blue governor this past election.

@AlexanderGruber If it's a maths question and somebody wants an answer to it and somebody else wants to give an answer to it then it belongs on a maths question and answer site.

@RobertFrost I disagree. "Give me an answer to $d/dx(x^3 -2x+ 9)$" is not the kind of math question belonging on this site.

@amWhy Then give Alexander your answer

By the way, I don't think that fits the criteria he listed

I already have... just saying, you misunderstand this site, @RobertFrost

@amWhy in your opinion

@AlexanderGruber On the topic of homeworky questions though. I think quite often a bigger issue than questions is answers. In many cases the answers do little more than solve the given problem. They don't actually add anything much above "these scribbles get you to the end". Also in many cases Hints would be much more useful from a teaching point of view than full answers but are rarely given.

@DRF I agree hints are helpful but I've often learnt a lot from a complete answer. Some people don't have the luxury of a teaching environment and from an answer, we often learn a method which can be adapted to other problems.

@RobertFrost I'm not saying it's always bad to give a complete answer. But I find many contributors provide complete answers in situations where there certainly aren't necessary and even more provide nothing but the dry answer. If we (rightly in my opinion) criticize questions for lacking context, thought and usefulness I think it might be reasonable to apply the same measure to answers. I say that with the knowledge that some of my own answers might be downvoted to oblivion.

@DRF I do the same but especiall with new users I Always explain what's expected of them. The stock closure answers are quite unfriendly and cryptic.

*closure reasons /explanations

@RobertFrost Also my experience is that most students (and let's face it 90%+ of the question the site gets are from students) already have access to many, many examples of solved problems where the methods they need to use are already presented. Adding one more to that arsenal is unlikely to help.

@DRF Particularly when said students haven't paid attention to such solved problems provided by their text, or in lecture, or online, and wait to the last minute to come here, expecting a user here at MSE to tutor them through two or three weeks (or an entire semester) of material they need to know to answer the question they ask. This is a Q and A site; not a tutoring site.

@DRF I was looking for a link. I'm a believer big in this: ux.stackexchange.com/questions/122360 If the questions keep coming then there is something wrong with the system. But some seem to treat the users like there is something wrong with the user.

@amWhy True of course. Then again sometimes I wouldn't mind tutoring someone and the chats are reasonably fine for that (I've done it a couple of times) it just doesn't really belong on the Q&A part of the site.

@DRF Indeed. I've done the same. There's no problem in that. Anyway, it seems like Robert Frost is trying to play tug-of-war with you, and I don't want to put you in that position from my end. But I've enjoyed our exchange today!

@RobertFrost That post makes sense in the case of for profit enterprises. When the people start paying me for the time I spend with them or when I start to pay SE for using it as a platform we can talk about whether I/SE are supposed to be more accommodating to the students/me so that they make more money and everyone is overall more satisfied. Till then that post makes no sense. Just because someone believes I know math and so they get to use me as a teacher doesn't actually give them any right.