12:33 PM
8

We came to think of this problem: Ali is a good Muslim who happens to travel a lot. On one occasion when Ali is praying, properly oriented towards Mecca, he notices that he is also facing exactly east. Where can Ali be? The geographical coordinates of Mecca are $21.4^\circ\text{N}$...

0

Suppose I have the piecewise function $f(x) = \begin{cases}1, & 0<x<1 \\ 0 & x>1 \end{cases}$ and I wanted to extend it to an even function over the entire real line. How would I do that? I know that normally for a function $\phi$ defined on the half line, the even extension would normally be ...

1 hour later…
1:50 PM
@JyrkiLahtonen Currently all questions tagged (straight-lines) are also tagged geometry). So I suppose it is possible to remove the tag from the remaining questions without bumping. (IIRC some of the mods mentioned that merging can be done without synonymizing two tags and that it effectively removes the tag.) Anyway, feel free to let me know here or in chat whether manual removal should continue or whether now it can be left to the moderators. — Martin Sleziak 24 secs ago
@quid If you happen to stumble upon this, you are probably able to say whether I remembered correctly that merging can be used to remove tags without bumping.
arjafi: "Merging into is the (silent) process by which the tags of questions are wholesale altered. Here, will be removed from all questions and replaced by (provided they don't already have that tag)."
Jeff Atwood: "I would ask here on a meta for a moderator to do it as a rename or merge which does not bump questions."
A good idea @MartinSleziak ! I ask other mods first, for they may know something I dont'. — Jyrki Lahtonen ♦ 1 min ago

2:31 PM
@MartinSleziak: Arthur told me that there should be no ill side-effects. It is now removed. — Jyrki Lahtonen ♦ 43 secs ago
So tag is now empty.

1 hour later…
3:46 PM
Since this question has been bumped, I had look at the tags.
14

$\forall {p_1\in\mathbb{P}, p_1>3},\ \exists {p_2\in\mathbb{P},\ p_3\in\mathbb{P}};\ (p_1 \neq p_2) \land (p_1\neq p_3) \land (p_1 = \frac{p_2+p_3}{2})$ Now I'm not a 100% sure about this, but I vaguely remember proving this once, but I cannot recall how I did it right now. It's also a bit li...

I think it falls under additive number theory. I have added as the closest approximation we have among the tags. But I am not entirely sure about that tag.

3 hours later…
6:34 PM
@MartinSleziak BTW the same question introduced also the tag qibla, but ist was removed since then. Wikipedia: Qibla.