## If n is a positive integer, then $n^3 + 5n$ is divisible by $6$.

Is this possible to prove through the induction method. It seems it is not to me. I built a base case, proceeded to substitute in k, then finally moved onto my $k+1$ case. Where I ended up with a ...

## Should I learn to use LaTex to write up a History Masters Thesis?

So I reviewed the "What are the advantages or disadvantages of using LaTeX for writing scientific publications?" (sorry can't link to it) question on this forum and am sitting on the fence at the ...

## What? No error?

Your task is simple. Write a program that should obviously produce an error on first glance either when compiled or run, but either doesn't or produces some other unrelated error. This is a popularity …

## Is there a name for the red circle and slash in a No Smoking sign?

When my daughter asked me and my husband about a No Smoking sign, we explained that it means no cigarettes are allowed. (We had to explain cigarettes to her too.) Unfortunately, she now thinks ...

## What's the inspiration for the owlbear?

The standard explanation for the owlbear in-universe is "A Wizard Did It." Which is fine, as far as it goes, because the trope of "madman tinkering with bizarre mutations" is part of our speculative …

## Do snapshots + RAID count as a good on-site backup solution?

The two main reasons I can think of for taking backups seems to be taken care of when I use both snapshots and RAID together with btrfs. (By RAID here, I mean RAID1 or 10) Accidental deletion of ...

## How to typeset basic arithmetic

What would be the best way to use TeX to typeset basic arithmetic as it's done in school - for example, to typeset equations like 356 + 42 --- 398 written in this way?

## Should I use “apt-get remove” or “apt-get purge”?

For uninstalling an app (or package) should I use apt-get remove package-name or apt-get purge package-name? What is advantage of any of them to other one?

## Best way to express 2014

In my class, I always write the date using mathematical formulas, or cool little equations. I want to show my students that even the most mundane seeming number often has fascinating features, and its …

## In left skewed data, what is the relationship between mean and median?

I found this question on the open MOOC from Stanford, however the answer is not present. I think the median $\leq$ mean. Is this the case?

## Why am I allowed to access protected Windows files when I boot Ubuntu from USB?

How come I'm allowed to reboot a computer that I don't own, put in a USB, boot ubuntu from it and then access all files stored on the drives available (even critical files such as system files on C …

## Time complexity of a compiler

I am interested in the time complexity of a compiler. Clearly this is a very complicated question as there are many compilers, compiler options and variables to consider. Specifically, I am interested …

## Set matrix zeros

I solved this problem in about 11 minutes (with all 50+ test cases passed). I think most of you already know me by now, and I truly appreciate your advice, but please be brutal and judge me as if I …

## If a subgroup $S$ of $G$ is Abelian (the subgroup, not the entire group!) then is $S$ a normal subgroup?

I saw a glimpse of similarity in their definitions and I thought I'd try to prove or disprove it. I have a feeling that it is true but my attempts to form a proof (that given an Abelian subgroup, ...

## Nazism and Jewish persecution awareness during the WW2 years

I've always wondered how is it possible that an entire nation and beyond (Germany) wasn't aware of the Jewish persecution during the WW2 years or, if they were, that they did nothing to stop it. Were …

## If DOS is single-tasking, how was multitasking possible in old version of Windows?

I read that DOS is single-tasking OS. If old version of Windows (also including Windows 95?) were just wrappers of DOS, how could Windows run as multi-tasking OS?

## Why is cross product only defined in 3 and 7 dimensions?

Why $3$ and $7$? I know from some reading that Hurwitz's Theorem explains this, but can someone help me build some intuition behind this or perhaps provide a simpler explanation? It still seems ...

## Can I abandon my Kerbonaut in space?

My little Kerbonaut is currently circling the planet in a stable orbit, and seems to be having a grand ol' time with it. You should see the smile on his face. He's been circling now for what looks ...

## Is it appropriate for an employer to ask skilled professionals to do manual labor?

Although I think it applies to many positions, I am a software developer (mid-level). The company is rather small (30-40). Recently, my employer brought up the idea that to help another department, …

## Why did this aircraft re-route?

I was looking through my ADSB Virtual Radar outputs couple days ago and saw a weird re-route for one of the aircraft that looked out of place. Can one of the pilots/ATC guys pitch in to help me ...

## Mandelbrot image in every language

I always used a Mandelbrot image as the 'graphical' version of Hello World in any graphical application I got my hands on. Now it's your guys' turn. Language must be capable of graphical output or …

## Good slide design for teaching?

When I am preparing slides for a course (as I have been today, weekend be damned), aside from questions of pacing and exposition, I often find myself asking various questions about the layout of ...

## How to draw an arrow with a different head?

I need to draw an arrow but with different head. The head should look like $\dashv$. And I do need to change the line. I tried with $--\dashv$, but it wasn't nice. Any idea? It should look like a ...

## Terminal, how to quit --More— list

I use autocomplete a lot in the terminal, like for example for cp command. But sometimes, when I am putting in the directory for the cp command and I press Tab, the list of files is so long that ...

## How do the streetcars in Toronto draw power from the lines?

I've tried googling this but to no avail. I've been trying to figure out how streetcars can draw power from a short circuit. For reference: If I imagine the power lines simplified as a shorted ...

## Disadvantages of scoped-based memory management

I really like scope-based memory management (SBMM), or RAII, as it is more commonly (confusingly?) referred to by the C++ community. As far as I know, except for C++ (and C), there's no other ...

## Fahrenheit 451 time period

Is there an allocated time period in Ray Bradbury's novel? I'm not too sure if there is a timeline that led up to the events in the book, so the time in which it is set is unclear to me.

## can I still wear my star of david

Hi I am just curious my mother is Jewish but my father is christian and I was raised in the christian church but I still have alot of respect for my jewish heritage, would it be wrong to wear a star …

## Logic to test for 3 of 4

I want to return true if and only if 3 out of 4 boolean values are true. The closest I've gotten is (x ^ y) ^ (a ^ b): What should I do?