Using Math.SE as a tool for my lecture/exercise

I am giving a lecture in a mathematical subject and in the exercise it turned out that many students had a big problem solving one particular homework. Since the calculation is longer and we have limited time in the exercise/lecture, I replied that I will send an E-mail with the solution to everyone. Then it occurred to me:

My thoughts:

• Answering my own questions is okay (and even very welcome, as it is formulated in the help center).
• For me it is much more convenient to write a short question/answer here with the embedded $$\LaTeX$$ instead of setting up a new document in a hopefully organized file structure and providing it to every student for which I have to create and maintain a mailing list.
• A question/answer on Math.SE will provide an easy accessible and well-organized source which I can use every semester.
• It might help students other than my own.
• Other answerers might be able to explain it better than I do.

Yes, I know that with this I make the solution to my homework "googleable". But I have no problem with this as I can change the problem formulation from time to time. Also my answer will contain an explanation instead of a copyable text.

Question:

• Do you think it is okay to use Math.SE for this purpose?
• Have you made experience with this idea?
• Should I mention in the question that it was asked with this purpose in mind?

Further context

The current question is about how to define the control points of a general cubic B-spline in order to automatically ensure $$C^2$$-continuity. This means the question is quite informative and not completely specialized for only one specific example. I want to answer this in full generality.

• My understanding is that answering your own questions is for the situation where you don't know the answer when you post the question, but then you figure it out. – Gerry Myerson Dec 8 '17 at 11:26
• @GerryMyerson The help center is very explicit about that this is not the only use case. Especially, when you write a question there is an option to directly include the (already known) answer in a separate input box without posting the question first. It's about documenting knowledge instead of gaining it. – M. Winter Dec 8 '17 at 11:37
• For what it's worth, here are some previous discussions: math.meta.stackexchange.com/questions/10898/… and math.meta.stackexchange.com/questions/4337/… and math.meta.stackexchange.com/questions/1839/… and math.meta.stackexchange.com/questions/15017/… and probably several more. – Gerry Myerson Dec 8 '17 at 11:49
• @M.Winter: Follow the first link in your help center blurb. My impression is that this has always been about "This is the sort of thing I would have searched stackexchange for, so I'll put it there for others!" rather than using stackexchange as a publishing platform. I would tentatively classify your usage as being sufficiently similar, but I haven't really thought the specifics through. – user14972 Dec 8 '17 at 20:40
• I have once answered my own question precisely for the benefit of letting people know about a not so well known proof of Taylor's theorem. In order to avoid letting it be seen as some sort of rep hunting, I made the post a community wiki. And I waited for some time before accepting the answer. This is a much easier option to spread knowledge compared to writing an article, or a blog post especially when the content is small in size. But obviously this shouldn't be done for run of the mill problems. – Paramanand Singh Dec 10 '17 at 4:07
• It's fine to answer your own question, however when asking a question you should make it clear to everyone that you already know the answer and intend to provide it, so that people wouldn't waste time answering it unless they have something more to add. – Anton Fetisov Dec 11 '17 at 3:30
• I wonder why you don't keep a website of your own for these sort of things. Having content in Stack Exchange means that you're relinquishing control and risking those "posts" to become too sparse such that it doesn't help your personal branding. – adib Dec 11 '17 at 9:20
• I don't understand why it is difficult to set up an organized Latex document to send out to your students. Presumably you have a template for such things, and have to already maintain an email list of your students for other purposes. – Morgan Rodgers Dec 13 '17 at 0:34
• @AntonFetisov you can answer at the same time as posting the question – can-ned_food Dec 13 '17 at 1:15

If you're posting a question and answer that that have long term value, then why not? By posting it on MathSE, you are not only making it easily accessible to your students, but to any future students you have or any anyone else studying the same topic. Also, it gives anyone else on the site, either now or in the future, the chance to weight in the question and to add their own answer to it that you hadn't thought of. That's like the whole point. A user may edit your question or answer, but the idea is that the edit will only be to improve the post or to clarify something; a user can't change the intent of a question or answer by editing it (at least that should be caught in the review queue).

Granted, such a question may not be well received here in terms of attention or getting upvotes, but I can't imagine such a question being downvoted or nominated for closure so long it has some long-term value and you type it up nicely. I've done this once before myself, granted for a much lower level of math than you are planning to, and the post didn't receive much attention besides from my students who visited it.

• Thank you very much for your answer and for sharing your experience with this idea. My biggest concern is that I get a bunch of down-votes and closing-attempts. It seems the concept of self-answering and using SE for knowledge sharing is not well established among the users. I am glad it went so well in your case! I also think of placing a small explanation of my intention below my question (as you did it), maybe with a link to this question to back-up my point. – M. Winter Dec 8 '17 at 19:24
• I agree. It is in keeping with the mission of Math.SE to promote learning "at all levels" to post Questions that are for the benefit of future Readers. Upvoting and Downvoting will occur as usual, as may Editing, but edits to the Question or to a self-Answer should not change the intent of original poster. – hardmath Dec 8 '17 at 20:00
• @M.Winter, yeah, adding a little explanation to the question is a good idea. I think that's all you need to avoid downvotes/closevotes, because that explanation adds "context" to the question. I'll guess that many users, when they vote to close an question, justify that vote because the question lacks context. – Mike Pierce Dec 8 '17 at 20:06

I rather like the general idea of exposing students to StackExchange. There is a lot to be gained, particularly for those students who haven't seen it before.

• It introduces students to a useful repository of mathematical information.
• Those who become users will obtain a gentle introduction to some useful technical tools such as LaTeX snippets and Markdown. They might be inspired to push things further to create images.
• They might become involved with the wider range of StackExchange sites.

Unfortunately, there are hazards such as rude users and poor information. This is probably a simple consequence of the size of the site and diversity of its users. We see even here in this Meta thread the lack of consensus that arises on a simple question that seems to have an affirmative answer according to help center.

I'd like to suggest an alternative. Every year, it becomes easier and easier to host and maintain your own forum. I've done this for about four years now and it's been tons of fun. You could certainly ask and answer the kind of question that you suggest but you can do much more. You can freely encourage your students to participate as well. This exposes students to the tools that they ultimately need to ask quality questions here on math.se but in a much safer environment and with your gentle instruction.

Tools that I've used to do this include

All of these are open source software that you can install on your own web server but they also all have pay versions someone else can get up and running almost immediately. Depending on your institutional support, it might not be super hard to get going.

• i.e. posting the example here could make it possible for other users to interfere with one's teaching – can-ned_food Dec 13 '17 at 1:19

There have been several links provided by Gerry in the comment concerning posting self-answered question in generel (My favorite is the answer by quid), so instead I wish to discuss your specific situation from an instructor's point of view.

I would prefer not posting anything concerning the course, since

• It is not under your sole control. Your question could be edited to notations that do not use in class. It might be closed, deleted and thus you can't even make sure it stays on the web throughout the span of your class.

• It cannot be course-specific. Due to your specific constraints (time, your students' background), you might want your answers to avoid some terminologies/method. Of course you cannot control that if you post it in MSE. So every year you have to tell the students "the answer that is really suitable for us is the forth one, with a net score -1 for the moment".

• It is just not convenient for the students. Lets say you have five answers posted on MSE that you wish to share with your students. So your students bookmark the link you give them and everytime they want the solution they go to that link. It is obviously less convenient than sending them a pdf containing all five questions and answers.

I would prefer posting everything on a website. The website can be re-used every year, and IMO it is more convenient for you and the students.

• I think this is already the standard practice. Most professors already have lecture notes (in PDF) available on their homepages in the university website. But this is more suitable for a printed copy. Any online content with mathjax is way better than those PDFs. For control over content one can create some sort of blog. – Paramanand Singh Dec 10 '17 at 4:14