First of all, thank you very much for attempting to educate your student about the guidelines and how to ask a question here. I sincerely hope we can help you and them grow as contributors.
On question gaps and OP
Roughly, when a question is asked by an OP (OP = Original poster, the asker of the question), there is a certain "gap" between the point where the OP is, and the actual answer. On occasions where it's clear that the gap can be filled with the information provided by the author, in a manner that the author understands it, someone posts an answer.(The guidelines capture these key pieces of information). Otherwise, people comment, in an effort to bridge the gap and make it a collaborative effort with the poster if necessary. If OP does nothing to address these gaps, then two problems occur :
Someone posts an answer, and I , as a visitor, don't know whether it's worked for the OP or not : I could say it's useful to me and vote it up, but I wouldn't know OP's response. It could perhaps stunt the organization of the site as well. For example, if your student had accepted the second answer in that question, then we'd have probably closed the question as a duplicate, given that duplicates using implicit differentiation are available.
There is no subsequent activity by commenters on the post because the OP hasn't help bridge the gap. Then closure/deletion etc. follow because the gap is likely to remain as such without OP participation.
Either way, the most important reason I'd imagine you asked your student to come to this site is because they would benefit from it. It is likely that neither of these situations is beneficial to them, unless an answer is perfectly on point : in this question missing that key piece of context regarding implicit differentiation, both answers use it!
What your student needs to do for sure
That's why I really think there's one very important thing that your student , and many posters when they don't know if they've provided enough context, need to do very diligently : it's to be receptive and reply to every comment/answer, and admit the fact that some things are going over their head if and when they are (which can be difficult to do particularly if the student fears being seen as dumb or feels embarrassed at not knowing certain facts/results). Therefore, your student should know that they can comment and refer to users using the @ functionality. Really, I genuinely believe this is the most beneficial action for a user that isn't sure on what context to add.
There will be two types of comments (some of both types). One will tell them what to add to their post. The other, will attempt to resolve their mathematical question. Both will be important, one to find the context in the question and the other to place that context in the original post. There are commenters that are willing to converse, improve the question and eventually help the user out : particularly if the question is of an elementary level and hence attracts a larger audience.
In this question e.g., a conversation may look like so :
Commenter : Do you know implicit differentiation? Here(link to some post) is a post that solves the same question using implicit differentiation.
Poster : No, I don't know implicit differentiation.
Commenter : Thanks. If I take out implicit differentiation, then it's likely that I might require a different tool. Are you aware of the arcsine , or inverse sine function?
Poster : Yes , but how can I use it here?
Commenter : Can you write $x$ in terms of $y$ using the arcsine function?
Poster : I think so , $y = \sin(xy)$ so $\arcsin y = xy$ so $\frac{\arcsin y}{y} = x$.
Commenter : Thanks. I believe you can find $\frac{dx}{dy}$ from here?
Poster : I don't know what is $\frac {dx}{dy}$ / Oh, then I use $\frac{dy}{dx} = \frac 1{\frac{dx}{dy}}$? / I don't know how to differentiate the arcsine function?
Commenter : Thanks: by the way ,consider adding ... to your post (although with newbies, perhaps context in comments may be good enough) , do you know the differentiation rule for inverse functions? etc.
and so on. If the question is closed then conversation can carry on, with emphasis on what can be added to the question for it to be reopened.
If I were a commenter, I'd probably ask for details on the textbook , questions such as : "did this appear as an exercise? If so, what was the last thing taught to you before you reached this question?" That might be enough context and is part of the "source" of the guidelines.
Benefits and issues
Providing the OP sticks it out in the comments, I can see one of two outcomes :
No commenter is able to completely help the OP, despite everybody's honest and entire efforts. In that case, one of two things happen : either someone writes a lengthy exemplary answer that addresses the OP's concern with its sheer breadth, or the OP recognizes the gap and attempts to bridge it with further questions/reading elsewhere. In short, it's a productive experience for the user.
The OP reaches a point where they can self-answer the question, or someone else can clearly see a way for the OP to reach the answer from the question using tools available to them that have come out in the comments, and writes an answer.
That shows clearly that open participation in the comments is the best way for users that may not know what context to provide to benefit from the question they've asked. The big problem is that a lot of things need to go the right way for the best experience : answerers need to be careful they don't confuse the OP, down-close votes should do their job and prompt improvement, and everybody including the OP needs to be available and open for conversation. Seven-eighths of the trouble is that one of these break and the question dies, with someone else to pick up the pieces perhaps.
Of course, another problem is that people are split over whether the site should be accommodative of questions with many back-and-forth comments , given that SE itself isn't very welcoming of discussion : but if someone doesn't have context, then they need to discuss this with users, and I think visitors and potential answerers are likely to be helpful in figuring out what context is needed when a question is posted, or while it is closed. That's my personal take on this issue.
What posters should definitely know as well
I would ideally love it if any new user read a MathJax tutorial, the guidelines page, and How to search on this site prior to posting questions. I still believe the most important thing is to be receptive to comments on one's question and respond quickly. MSE is not Quora,reddit etc. so the format and system may be off-putting. In any case, we need to help new users integrate, and likewise new users need to make sure they want to be helped. I consider what I've said to be the primary way to do it smoothly.
