I created this trigonometric formula for finding the area of oblique triangles: $$R=\frac{(a^2+b^2-c^2)^2\sec C\tan C}{8ab}$$ where $a, b$ and $c$ are sides of the triangle, angle $C$ is the angle opposite to side $c$, and $R$ is the area.

Does this formula deserve being in textbooks or contests? And where can I publish this or find out if someone already discovered the formula?

Also see this post Have I found a formula for the area of a triangle?

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    I dont know if this is correct, but its certainly a nice looking formula. You probably can't get this posted in a journal but you might be able to write a blog post or post an article in a math magazine that collects other results like this and talks about how it is derived. I have to be honest though, I would expect a result such as this to already have been discovered earlier, but in the rare chance that it for some reason hasn't been (or it has been but long forgotten) you could still take the aforementioned actions – Sidharth Ghoshal Jan 05 '22 at 23:20
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    For the record, your question is probably off topic here (although I'll personally not downvote it). Math.SE is usually exclusively for asking specific mathematical questions as opposed to more general math-related questions (ex: can i publish X, how to get a job as a mathematician, etc...) – Sidharth Ghoshal Jan 05 '22 at 23:23
  • @frogeyedpeas Thanks for your opinion! –  Jan 05 '22 at 23:26
  • @frogeyedpeas so it's not a soft question? –  Jan 05 '22 at 23:27
  • No a soft question should be used for soft mathematical question, basically questions that are close to being mathematical but whose scope has a level of opinion/external influence: A nice example is: https://math.stackexchange.com/questions/2821112/integral-milking here the asker has a very "vague" notion that they make specific through examples and metaphors and they wish to turn this notion into a concrete strategy. There's a lot of opinion/philosophy that can go into answer to this question, its not a clear cut mathematical problem. So they attach the soft-question tag to it. – Sidharth Ghoshal Jan 05 '22 at 23:31
  • So I have to delete this question? –  Jan 05 '22 at 23:33
  • You don't have to delete it. It might get closed. But, you can leave it up. – J126 Jan 05 '22 at 23:34
  • Here is another example thats maybe a bit more down to earth: https://math.stackexchange.com/questions/2644700/whats-new-in-higher-dimensions, again the asker is basically looking for some opinionated/unstructured ideas for "how to think about higher dimensions". Now you might believe your question is opinionated and vague BUT you're asking a question about the real world, not mathematics, you're asking is something publishable so thats why its not really a math question. – Sidharth Ghoshal Jan 05 '22 at 23:34
  • Now you do have some options here, you can instead phrase as your question as: "Where can I find results similar to mine" and then add a reference-request tag. Perhaps some expert geometers might be able to point you in a useful direction. – Sidharth Ghoshal Jan 05 '22 at 23:35
  • Okay, thanks for your recommendation! –  Jan 05 '22 at 23:36
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    I removed the soft-question tag, and added a publishing tag. There is a maximum of five tags. – J126 Jan 05 '22 at 23:37
  • @J126 Thanks for your help! My reputation just reached 100! –  Jan 05 '22 at 23:38
  • @J126 I didn't even know we had that tag! Looks like I need to refresh my knowledge :) – Sidharth Ghoshal Jan 05 '22 at 23:40
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    Questions of the form "have I discovered something new?" are less useful than specific mathematical questions that support your learning. – Karl Jan 05 '22 at 23:43
  • @frogeyedpeas So many tags. It's weird that so many of them have zero questions attached. – J126 Jan 06 '22 at 01:20
  • You should mention your previous question ! https://math.stackexchange.com/q/4349687 – Jean Marie Jan 06 '22 at 09:00
  • @JeanMarie should've thanks! –  Jan 07 '22 at 02:11

1 Answers1


I can do you one better. $$ A=\frac{1}{2}ab \sin C. $$ This identity is equivalent to yours after a use of the Law of Cosines.

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    I've seen this formula before. What do you mean by "I can do you one better?" –  Jan 05 '22 at 23:31
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    Also where do you get so much reputation –  Jan 05 '22 at 23:31
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    @KamalSaleh I was trying to be cheeky. I just meant that this formula is closely related but a bit simpler than yours. – subrosar Jan 05 '22 at 23:32
  • @KamalSaleh you can click on subrosar's profile and see the questions and answers they have posted. This user has put in a lot of work, with some 117 answers as well as many questions. Hence they have such a high reputation. As you get more skilled at mathematics you too might be able to do the same. A good first step is just showing up to the site and asking questions the way you are doing right now. – Sidharth Ghoshal Jan 05 '22 at 23:45
  • @frogeyedpeas That does make sense why he has lots of reputation. –  Jan 05 '22 at 23:49