Question: I've seen a lot of questions of rather elementary limits (most of them 'highschool' level), where users answer saying things like

> 
> "Note that $\sin x =\sum \frac {(-1)^n}{(2n+1)!}x^{2n+1}$, then it's rather trivial $\dots$"
> 
> 
> 

Or

> 
> "Just remember that $\sqrt x \in o(x)$, then $\dots$"
> 
> 
> 

I'm always disappointed at seeing answers like that, it's utterly obvious they'll be useless for the one asking the question (and most of the times it's really kind of "killing an ant with a nuclear bomb").

What do you guys think?

Answer: 
1. You have no way of knowing if the answer will truly be useless to the one asking the question.
2. "killing an ant with a nuclear bomb" So what? Is it a bad thing?
3. Answers are for everyone, not just the OP. Maybe these answers will be helpful to someone else. Considering that questions get closed for being duplicate of one another, if someone asks a question about some limit but displays high-school level knowledge, does it mean that everyone is forbidden from ever answering this limit using power series on this site?
In general I won't down vote an answer just because the answer is an overkill. That kind of answers might provide the asker a new way of thinking the problem that (s)he never sees before (like asymptotic equivalent in your examples).

I'll, however, consider down-voting an answer if the answer use a technique that the question explicitly stated to not use (e.g. Use L'hopital when it's stated in the question that it's not allowed).

Contrary to what you think, the community seems to dislike the opposite- trying to crack a hard problem using elementary approach while using more advanced tool can yield a simpler and more natural solution. For example, the following answers I wrote that got down-vote(s).

[example 1](https://math.stackexchange.com/questions/972765/what-is-the-minimum-value-of-tan2a-2-tan2b-2-tan2c-2-where/972798#972798)

[example 2](https://math.stackexchange.com/questions/1639327/in-need-of-assistance-with-evaluation-of-a-tricky-limit/1639351#1639351)

[example 3](https://math.stackexchange.com/questions/1648482/how-to-find-approximate-value-of-1-01e1-010-99-2/1648494#1648494)