# Talk:Derivative of Sine Function/Proof 5

This proof was inspired by a comment by "man on laptop" on https://math.stackexchange.com/questions/75130/how-to-prove-that-lim-limits-x-to0-frac-sin-xx-1?noredirect=1&lq=1 This is not a source allowed by the house style. I note it here to avoid plagiarism. --Pelliott (talk) 14:02, 27 January 2019 (EST)

The reason it's not allowed is because such sites are ephemeral. If I can be convinced that links to pages on stackexchange are permanent, then we may consider adding it to one of our acceptable sources.
The alternative is that you just don't pinch stuff you find from there, or second-source it. --prime mover (talk) 18:21, 26 January 2019 (EST)
Okay, so I have created the template {{Stackexchange}}, which is a convenient way of generating a uniform citation link back to the pages on Stackexchange that source the material in question.
Now, I'm not familiar with Stackexchange myself, having found it a little socially inaccessible, so I am unfamiliar with accepted forms of the citation. I understand the required format is not hard-and-fast, as long as the information is there. I copied the format given directly from the "cite" field of the page under discussion.
So, please feel free to suggest alterations to the presentational style according to how you think it might be expected to look (or if you are familiar enough with MediaWiki software, make those amendments yourself), and go to it. --prime mover (talk) 19:24, 26 January 2019 (EST)

I did not pinch anything. Ideas are not copyright-able. The particular expression of an idea is copyright-able. 3 concepts were mentioned together. This suggested the answer, that is, the particular expression. If you could not use other peoples' ideas, this whole project would be illegal. However, academic practice is to reveal source of ideas. Otherwise, people start yelling about plagiarism, even though you have not done anything legally wrong.

The purpose of credit, is to stop people from yelling about plagiarism. Not to stop "pinching" i.e. copyright violation, because legally, you can take all the ideas you want and never give any credit. If you want academics to contribute here, you must give them a way to contribute, without risking their careers with a charge of plagiarism. That is, you must give them a way to document their sources, even if those sources are not "general citation sources". Ephemeral is not relevant to this issue. Nobody in academia ever got accused of plagiarism, because a book went out of print. Sometimes a person is listed as an "author" of a mathematical work, because of a discussion in a hallway. It happens. I understand you do not want to clutter up the sources section with a bunch of broken links. Perhaps you could make it policy to put non general citation sources on the discussion page. That way everyone could be safe from attack.

In this context, where the results being discussed are problems set as school homework, I don't think anyone's going to express concern about plagiarism. If the proof were good and original, maybe. --prime mover (talk) 05:08, 27 January 2019 (EST)

By the way, the ideas in this proof are so simple and easy, that I suspect that "man on laptop"s discovery is not original. In other words, it is probably a rediscovery. If anyone knows who published this idea first, please tell us and I will give credit. Who knows? It could be Leibniz or Newton.

There's little point worrying about it in this case, as it's an unwieldy proof that (while it merits inclusion just by existing) is not particularly remarkable, I'm afraid (in my possibly limited view), and would probably not merit inclusion in a published work on calculus except as a curiosity. --prime mover (talk) 05:08, 27 January 2019 (EST)

I have read too many books on topology. Often, their proofs read like a novel. It may take a while for me to get used to the style here.--Pelliott (talk) 14:02, 27 January 2019 (EST)

Incidentally, you are invited (and encouraged) to sign your posts. --prime mover (talk) 05:08, 27 January 2019 (EST)