When I posted an answer from my another profile, it reached, in the first two seconds after posting, very bad score. Of course, it is always possible that someone simply dislike the answer, or the poster, or nickname, or anything. However, reaching score of -3 in the first few seconds after posting is something very concerning me.

This is the answer I'm talking about. I'm trying to see what is wrong in the answer, but I still have no idea. If there is some typo, someone usually leaves a comment without voting. However, very negative score may be reached only if the poster of the answer shows completely misunderstanding of the problem or provides completely useless information.

I would like to improve the answer, but without comment I really have no idea what people see so horrible in the answer. I tried to check if I maybe hhave made some miscalculations, but I think it is correct. Therefore, I'm not sure what to improve.

Why I've asking this here: simply because I don't see what is wrong with the answer and I would really like to improve it. If it turns out that nothing is wrong, but people just simply dislike that answer, I would leave it there, no matter how bad score is. But, I think it would be better to improve if something can be improved.

I would ask you to take a look at the answer and tell me what is wrong with it. Does it provide useless information or does it contain wrong math formula or wrong calculations?

Thank you in advance.

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    $\begingroup$ Why not ask this question from the account in question?: @ThePirateBay ? That's the account from which the answer you speak of originated. $\endgroup$
    – amWhy
    Nov 26, 2017 at 20:12
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    $\begingroup$ Just note that math.stackexchange.com/posts/2523610/revisions is a violation of the rules. Your second account received points for an edit this account was supposed to make. $\endgroup$
    – Asaf Karagila Mod
    Nov 26, 2017 at 21:01
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    $\begingroup$ Indeed (thanks, @Asaf). Two independent accounts owned by one user is acceptable, unless one account supports the other account, e.g., the case Asaf points out, or one account upvoting another account, or answering another account. I think it is also not appropriate to post a meta question on behalf of one's other account either. You have a problem occurring in one of the accounts answers, any meta posts about it should be posted by the account that answered.... etc. $\endgroup$
    – amWhy
    Nov 26, 2017 at 21:14
  • $\begingroup$ @amWhy. Ok, maybe you are right. Even if I fix all issues with my answer, there are still better answers on that question and my answer will not be very helpful. As your wish, I deleted it, and I'm sory if I insulted you or wronged you in any way :) $\endgroup$
    – user503399
    Nov 28, 2017 at 14:10

1 Answer 1


I would ask you to take a look at the answer and tell me what is wrong with it. Does it provide useless information or does it contain wrong math formula or wrong calculations?

Here we go.

Because $x^x$ has it's limit at $x\to0$ (and the limit is $1$), it can be written as

$$\begin{align}\lim_{x\to 0^+}{x^{x^x} -1}&=0^{\lim_{x\to 0^+}{{x^x} }}-1\\&=0^1-1\\&=0-1\\&=-1\end{align}$$

First, there are grammatical mistakes in the first sentence: it should be "its limit", not "it's limit". One could say something like "limit as $x\to 0$" or "continuity at some point", but "limit at $x\to 0$" is rather strange. Moreover, "$x\to 0$" should really be $x\to 0+$. So you could simply say $$ \lim_{x\to 0+}x^x=1. $$

Note that when you prove this limit later, "proof" is a noun, not a verb.

Important: Notice that in this case the limit can be split into two limits just because both $x$ and $x^x$ have finite limits at $x\to0^+$ and because they do not form indeterminate expression (see the edit below, I'm sorry if someone misunderstood what I was trying to say).


If we have any two functions $f$ and $g$ such that $$\lim_{x\to x_0}f(x)^{g(x)}$$ then it is indeed equal to $$\left(\lim_{x\to x_0}f(x)\right)^{\lim_{x\to x_0}g(x)}$$ if both $f(x)$ and $g(x)$ have finite limit at $x\to x_0$ and if they do not form indeterminate expression. That is what I have said at the beginning of my answer.

I don't think I understand what you are talking about by "If we have any two functions $f$ and $g$ such that $\lim_{x\to x_0}f(x)^{g(x)}$". Did you notice that "$\lim_{x\to x_0}f(x)^{g(x)}$" is not a statement? Moreover, $f(x)^{g(x)}$ is not necessarily defined for arbitrary $f$ and $g$.

One can guess though, you are referring to the following statement:

Note that $a^b:=e^{b\ln a}$ for $a>0$. Suppose $f$ and $g$ are two functions such that both $\lim_{x\to x_0}f(x)$ and $\lim_{x\to x_0}g(x)$ exist. Moreover $f$ is strictly positive and $\lim_{x\to x_0}f(x)>0$. Then $$ \lim_{x\to x_0}f(x)^{g(x)}=(\lim_{x\to x_0}f(x))^{\lim_{x\to x_0}g(x)}. $$

Saying that this is true "if they do not form indeterminate expression" seems begging the question: one could ask "why is that so"? Logical correctness does not substitute clarity. Giving a proof of the statement or at least a sketch of it would be much more convincing than a lengthy "mumble jumble".

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    $\begingroup$ @Math_974 A mathematician can read your answer, understand what you're trying to write, and then conclude that you're missing so many of the details that it's not helpful. A student can read your answer and be completely confused and mislead. $\endgroup$
    – user296602
    Nov 27, 2017 at 16:10
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    $\begingroup$ @Math_974: "You are talking mostly about grammar issues." I am talking about serious mathematical issues after the sentence "Note that when you prove this limit later, 'proof' is a noun, not a verb." Also, please note that you explicitly asked in the title of your post "How to improve (my) answer". I'm assuming you are seriously looking for improvement, not voting. $\endgroup$
    – user9464
    Nov 27, 2017 at 16:46
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    $\begingroup$ You are targetting the wrong audience. No mathematicians would need to read your proof to know how to do that question. $\endgroup$
    – user99914
    Nov 27, 2017 at 18:18
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    $\begingroup$ Ok, thanks to anyone who helped in explaining what is wrong with the answer. At least, I know what not to do in the future. Anyway, even if I fix all issues in the answer, there are still much better answers, so my answer will be useless. It seems that sometimes it is better to accept what community says :) $\endgroup$
    – user503399
    Nov 28, 2017 at 14:08

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