# This is a sandbox

You can use this question as a formatting sandbox (if you can edit CW questions), and you can post answers if you want to test out formatting there as well.

NB: It's hard not to like this meta post but please keep it downvoted to -8 or less (rather than upvoting it) so that it doesn't get bumped to the front meta page every time someone is experimenting in the sandbox, which usually is not interesting to anyone else.

• In line with meta.stackexchange.com/questions/3122, but math/formulas don't work there. Jan 31 '11 at 19:26
• @ David Zaslavsky: thanks. Don't the formulas work here on meta? The original post is at physics.stackexchange.com/questions/2372/… Feb 1 '11 at 9:01
• Oh wait, LaTeX doesn't work in MeTa Jun 28 '13 at 15:26
• Links work in comments. Use the [text](url) syntax. Jul 2 '13 at 19:33
• @Manishearth Can we have a periodic clean-up of this thread? It's a huge unsightly mess. A few comments are worth keeping, but it'll be a lot nicer to use this Sandbox if it gets a good plow-through now and then. (Edit: actually, no, let me make this a flag. stupid of me.) Sep 13 '13 at 22:35
• @DImension10AbhimanyuPS That one was long, contained a lot of images (which made it hard to find the end of it/scroll), and was bothering others. Sep 14 '13 at 4:12
• @DImension10AbhimanyuPS No need for it. FWIW, the post will still be bumped to meta front page anyway. Sep 14 '13 at 4:23
• @Manishearth: No, it won't. I just edited this post with -10 votes and it doesn't bump the fIrst page. Sep 14 '13 at 4:29
• @DImension10AbhimanyuPS This is meta. Sep 14 '13 at 4:30
• @Manishearth: Even on meta. I retagged this post just now; it doesn't bump the first page. Sep 14 '13 at 4:33
• @DImension10AbhimanyuPS Yet the formatting sandbox is at the top of the main page. There's some criteria other than votes which I forgot about. Sep 14 '13 at 4:36
• Please don't rollback Sep 14 '13 at 4:36
• @DImension10AbhimanyuPS IIRC the edits to the question don't bump, but edits to the answers and new answers do. The vote threshhold is -4. meta.stackexchange.com/a/48579/178438 Sep 14 '13 at 4:38
• @EmilioPisanty: I have one thing to say to that: ♦.♦ Sep 14 '13 at 15:18
• @Manishearth it's the weirdest thing, though. An edit to a deleted answer seems to have brought the page to the top. I don't know if that's by design or not; I'll ask the corresponding question/experiment in a bit. Sep 14 '13 at 15:29

## 7 Answers

Some apparent redspace problems, 10 m/s (original post):

The period of a pendulum of length $h$ for small oscillations is $2\pi \sqrt{h/g}$, with $g$ the acceleration due to gravity, about $10 m/s$.

Sοurce:

The period of a pendulum of length $h$ for small oscillations
is $2\pi \sqrt{h/g}$, with $g$ the acceleration due to gravity,
about $10 m/s$.


Test post to test something (see comment)

gibberishwaE RscSA

gibberish .......qawr ASDCSaASFAF

gibberish

Mars Is Earth. , Manish Earth wrote this post.

• Identity theft! ‮ ♦ yksvalsaZ divaD May 8 '12 at 13:56
• Just a note: The above comment is a test case for this: meta.stackexchange.com/q/131818/178438 . The comment was made by me, to display how usernames can be spoofed (doesn't work on MSO due to different styles for links). May 8 '12 at 15:21
• I don't think I particularly needed to add the extra em dash, realized that now. May 9 '12 at 4:51
• Identity theft! ‮♦ yksvalsaZ divaD May 9 '12 at 6:17
• @dimension10 Oh, no problem, that comment is OK. ;-) Jul 6 '13 at 8:26
• The original owner Sep 14 '13 at 15:46
• Nope. Community wiki posts have different behavior when it comes to votes and edits, but otherwise the original poster is the owner Sep 14 '13 at 15:50
• Big Bang ‮‮ Is that so? - Sep 14 '13 at 20:23
• Test test test test test Nov 18 '13 at 4:53

Given $\left\{ a_{n}\::\:n=1,\:2,\:3,\:\cdots\right\}$ is an infinite sequence in $\mathbb{R}$, and every term is positive. How to prove that the set

$$\left\{ \frac{2+a_{n}}{\sqrt{2+a_{n}^{2}}}\::\:n=1,\:2,\:3,\:\cdots\right\}$$ has a limit point?

Bolzano-Weierstrass theorem says that every bounded infinite subset of $\mathbb{R}$ has a limit point. But how to prove it is bounded? I tried this $$\left|\frac{2+a_{n}}{\sqrt{2+a_{n}^{2}}}\right|\leq\left|\frac{2+a_{n}}{\sqrt{a_{n}^{2}}}\right|=\left|\frac{2+a_{n}}{a_{n}}\right|$$ but does not seem work.

Or these is another way to show it has a limit point, without using Bolzano-Weierstrass theorem

Let me check if the sandbox at -8 goes to the front meta page if I add a new answer.

• Long message <html> <body><br> <br><br> </body></html>________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ end
– Qmechanic Mod
Dec 9 '16 at 12:58
• Sandbox on Mother Meta (Warning: Slow to load.)
– Qmechanic Mod
Dec 9 '16 at 13:29

I greet you, people from a decade ago, from the far future land of 2021.

I’m testing whether it’s still the case that activity on this highly-downvoted post is still hidden from the main page.

this is a sandbox {$$1\frac2$$

[done, feel free to reuse this post]