# Should I add a tag to somene else's question (to reflect the content of answers)?

I found a simple solution to sum a series with trigonometric functions by converting it into a telescoping sum, and posted an answer. However, the OP did not mention about telescoping in their question; what's more, the accepted answer does not rely on the concept, either (instead, it utilizes a summing of a geometric complex series).

The question was Proof explanation for a sum of sines (closed as a duplicate now).

So my question is: would it be appropriate to add the to the question..?
Taking into account that would be some kind of a self-promotion due to a connection with my answer more than with the original question...

I found a similar question here: Why shouldn't I add a tag to increase visibility?
However, I don't feel it answers my question clearly enough.

• Related: Retagging after an answer is given. Mar 22 at 10:51
• The downvotes mean that people disagree with the idea, not that your question was asked badly, but you probably have enough rep to know that Mar 22 at 16:01
• It's stupid. If wise people disagree with an idea, they say it, not piss at it. Enough downvotes will cause the question disappear. Then other users with similar doubts will be unable to find it, hence will be forced to ask the same or similar question again. And again.... And the downvoters will be forced to downvote again... and again... And they will get more and more frustrated with the recurring question. If you're correct, @SomeGuy, then they're simply shooting their own feet. But who cares...? It's their feet, not mine. :) I've got the answer and don't care about this post any more. Mar 22 at 16:13

The question in the title and the question in the body of your post are subtly different.

Title question(see a note below): Yes, adding appropriate tags to questions on the site is good for the site and should be done. The aim of the site is to have an easily-searchable repository of mathematics knowledge and tagging questions appropriately aids in the searching. If you've ever noticed some of the complaints about how hard it can be to find duplicates, even when you know they do/must exist, you can see that good tagging is worth its weight in gold. It can hard for question askers to identify the correct tags as often, if they knew the right tag it would help them in solving their question.

Body question: This is a bit harder to answer, however I think it would be wrong to add the tag telescopic-series to the question just because you have an answer that makes use of that. If the question had asked for an answer of that form, or it is the only reasonable way to obtain the answer, then it would be appropriate to add the tag. If it were possible to tag answers then it would certainly be useful to tag the answer; sadly this is not possible.

The question to ask yourself before adding (or deleting!) a tag is really: does this tag make the question easier for people interested in this issue easier to find when searching? If your answer is no, it's probably better to leave the tags be.

Note (by OP): that part refers to the title 'Should I add a tag to somene else's question', as it was before I appended the '(to reflect the content of answers)' part.
CiaPan

• The tag would make it easier for people interested in telescoping series to find the question when searching. Mar 22 at 11:20
• Yes, I realized the title was too short and might actually read '...to add a tag [...] after an answer was added with unexpected method of solving' – but then virtually nothing would remain to be posted as a question itself. :) Anyway I think I'll refrain from adding the tag. It is not that important, and if someone seeks telescoping sums, they may find that particular answer by the text search, too. Thank you for sharing your opinion. Mar 22 at 12:19
• I modified the first subheading in your reply to explain the context, which has changed after I expanded the question's title. Mar 22 at 14:04
• @CiaPan ok, thank-you :) Mar 22 at 14:06