How can I find an international flight number?
Historical flight data outside of the USA?
Proving ${n \choose p} \equiv \Bigl[\frac{n}{p}\Bigr] \ (\text{mod} \ p)$ Okami is now reborn in High Definition for PS3. The graphics are obviously better, sharper and yet preserves the gist of the original game, however I can swear some of the texts have changed as well.  My PS2 console is no longer available to me so I can't test it myself, but does anyone know whether there are any changes to the game (aside from graphics) or not? How do I copy an entire directory into a directory of the same name without replacing the content in the destination directory? (instead, I would like to add to the contents of the destination folder) Let $A\in M_{n\times n}(\Bbb R)$ so that $I\notin span(A,A^2,...,A^n)$. Prove that $\det(A)=0$. Let $A\in M_{n\times n}(\Bbb R)$ so that $I\notin span(A,A^2,...,A^n)$. Prove that $\det(A)=0$.   I was thinking of showing $A$ is not invertible, meaning it has an eigenvalue of $0$. Since no matter the power you give to $A$, it is still not the identity, you can deduce that at least one eigenvalue is indeed $0$. However this doesn't work if you have different eigenvalues in the Matrix, so I got stuck.  Help will be most appreciated. Which partition is mounted to where? How do I find out which program and process ID accesses a given IP address in Windows? Is it possible to catch, which program is accessing a specific IP address?   I found my computer is flooding and wish to check addresses one by one.  May be it is possible to set up some audit for this? How to cleanly launch a GUI app via the Terminal? Where can I learn the meanings of RPG terminology? Words like 'campaign', 'system', 'dX', etc. Is there a good web resource with them all on a single page? What does "formal" mean? I know the definition of formal power series, power series and polynomials. But what does the adjective "formal" mean? In , does it mean "9. Of or relating to linguistic or logical form as opposed to function or meaning" or maybe another one in the link?   Or does "formal" have some mathematical meaning which is other than usual dictionary meaning? How is a generator found for a group, both in case of DH & ECDH? Today, on C.SE, I reviewed some 'Late Answers' and First Posts.  I was not even near my daily vote limit.  And yet, I was given a message that said      comments disabled on deleted / locked posts / reviews   It seems I was not the only one either:   The workaround, of course, was simply to go back and provide the guidance - but was this a design or a bug?  If it is design, why would you want to discourage the feedback? Especially with first posts, there is often a high percentage of 'didn't read the FAQ' usage, which can best be addressed by gently providing guidance. (e.g. "Unfortunately, this doesn't answer the question" or "This reads like a comment" or "This really isn't on-topic here - can I suggest you checkout our [faq]" etc...)  Timely first post guidance goes a long way towards making good users.   If it was a bug, was other functionality silently rolled out? Learning Regular Expressions Consecutively Adding Sines One thing, I'm not a mathematician so please be patient. I am still in Algebra II Trig. Leading with that, why does  $$ x_0 = \sin 1, \space  x_1 = x_0 + \sin x_0, \space x_2 = x_1 + \sin x_1 ... $$ and after a while, $$ x = \pi $$  I know this to be true because I have evaluated this on my TI-84 and more deeply evaluated it with this program I made:   To $100000$ Iterations (which I believe is enough)   So what's the math behind it? Why does adding $\sin 1$ in this manner produce $\pi$? Why doesn't doing the same thing using $100$ produce $\pi$? For example,  $$\sin(1) = 0.841470...,\space \sin(1) + \sin(0.8414...), \sin(1) + \sin(0.841470...) + \sin(1.587095126...),\space ... $$ $$ = \pi$$  My question is different from the mentioned because my function is not taking the sin of a sin consecutively, but is this following function: $f(x) = x + \sin x$ and is not $f(x) = \sin x$ and therefore can exhibit different properties I need explained. Per the title, does $\displaystyle\sum_{n=1}^{\infty} \sin(\pi(2+\sqrt{3})^n)$ converge? Converge absolutely?   I'm stuck on this question, not sure how to approach it.  Thank you! How to input integer value to an array, based preceeding row + column values? Set "default" monitor I would like to be able to set my "default" monitor to be my external 25' monitor instead of my laptop one when I have my external monitor connected.  Many applications always open on the laptops monitor instead of the "big" one. Currently, the only way I know to disable this behavior is to disable the laptop monitor, however, as I use a laptop stand to bring it higher, Id like to be able to use my laptop monitor as a "secondary" monitor, without dock (launcher) and without any windows opening on it.  The only way for a window to reach it would be to actually manually grab it and drag it over.  Some known applications that ALWAYS open on the laptop monitor and drive me crazy: Slack, Rocket Chat, Thunderbird, Sky, System Settings, Guake (specially annoying since i cant move it). SQL Server 2012 Page Life Expectancy resets to 0 after about 50 days I've noticed an odd behavior on a 2-server HA cluster and I was hoping someone could confirm my suspicion, or maybe offer some other explanation... Here is my setup:   A 2-server SQL 2012 SP1 installation SQL AlwaysOn HA has been enabled for a few databases CPUs are 2.4GHz, 4 cores RAM is 34 GB (it is an AWS instance, hence the odd number) Resource utilization is relatively low - each server has 14+ GB memory free, and SQL is not capped on how much memory to use Disk access time is fine - rarely going over 15ms/Read or Write Databases are not big - 1 GB, 1.5 GB, 7.5 GB SQL server process is using 16 GB Private Bytes, 15 GB Working Set   Overall, no resource issues are noted. Now for the odd part. SQL is not restarted (process has been running for almost 6 months) but it seems that every ~50 days, the Page Life Expectancy counter drops to (almost) 0. Up until that point it climbs steadily, no drops. Here is a perf graph:    When I look at the counter data (I don't have the exact number, just an hourly aggregation) it seems the PLE counter value reached about 4,295,000 sec (roughly 50 days) every time (at least every time I have data for).   My crazy theory is that the PLE number is held as milliseconds as an unsigned long int (which has a limit of 4,294,967,295) and at 49.71 days it resets, either by design, or because of a bug. This would explain the behavior of the two servers and the identical pattern they have. Or it could be something totally different and I am just not making any sense. :)  Has anyone seen anything like that, or can explain this behavior?  P.S. I saw  post, but my case seems slightly different.  P.P.S. This is a repost - I originally posted it , but was advised the audience here is more appropriate.  Thanks! Constants in Objective-C I'm developing a  application, and I'm using constant NSStrings as ways to store key names for my preferences.  I understand this is a good idea because it allows easy changing of keys if necessary. Plus, it's the whole 'separate your data from your logic' notion.     Anyway, is there a good way to make these constants defined once for the whole application?     I'm sure that there's an easy and intelligent way, but right now my classes just redefine the ones they use. I am watching Susskinds's lecture , in which he introduced square angular momentum operator $L^2$, which can be written as $$ L^2=L_z^2+L_-L_++L_z $$ where $$ L_\pm=L_x\pm iL_y $$  Besides, he argued that the spectrum of $L$ can only be $m,m-1,\cdots,-m+1,-m$ in which $m$ is an integer or half-integer. If we denote $|m\rangle$ the eigenvector corresponds to eigenvalue $m$, we have $$ L_\pm|l\rangle=|l\pm 1\rangle\;\text{or}\;0 $$  In the lecture he showed that $L^2|m\rangle=m(m+1)|m\rangle$ for $m$ the highest eigenvalue, by $$ \begin{align*} L^2|m\rangle&amp;=L_z^2|m\rangle+L_-L_+|m\rangle+L_z|m\rangle\\ &amp;=m^2|m\rangle+0+m|m\rangle\\ &amp;=m(m+1)|m\rangle \end{align*} $$  Then he left an exercise to show that for any $-m\leqslant l&lt; m$, we also have $|l\rangle$ is an eigenvector of $L^2$ with eigenvalue $m(m+1)$.  In the lecture, he hinted by showing that it suffices to show that $L^2$ commutes with $L_i$ for $i=x,y,z$, which gives us $$ L^2|m-1\rangle=L^2L_-|m\rangle=L_-L^2|m\rangle=L_-m(m+1)|m\rangle=m(m+1)L_-|m\rangle=m(m-1)|m-1\rangle $$  I believe it is true since I find the   online.   However, my question is that, why the following proof is wrong.  I tried to mimic the proof for $|m\rangle$ to have that  $$ \begin{align*} L^2|k\rangle&amp;=L_z^2|k\rangle+L_-L_+|k\rangle+L_z|k\rangle\\ &amp;=k^2|k\rangle+L_-L_+|k+1\rangle+k|k\rangle\\ &amp;=k^2|k\rangle+|k\rangle+k|k\rangle\\ &amp;=(k^2+k+1)|k\rangle \end{align*} $$  which shows that $|k\rangle$ does not have eigenvalue $m(m+1)$ but $k^2+k+1$ for $k&lt;m$. Switching baselayers as user zooms in to map in OpenLayers?