I have been starting back in school after a long hiatus.  In one of my classes, a discussion of Truth began.  The problem I have had is that no one seems to have a solid definition between the two.   My earlier training and schooling left me with this definition, and I would like some feedback.  Fact - A point of data that can be directly qualified/quantified through confirmed, standardized measurement.  Truth - A point of data not directly qualified/quantified through confirmed, standardized measurement.  So fact would be that ice cream is cold, as we can place a measurement of the temperature.  Ice cream being tasty would be truth, as it is impossible to accurately measure "tasty".  Please let me know your thoughts.

I'm curious about the difference between Fact and Truth. I was searching on the internet if I could find it. But still I'm confused about the exact meaning. I first read the forum discussion here  where an author has given two examples for each like below     A fact is a reality that cannot be logically disputed or rejected. If   I say "fire is hot," I don't care how great your reasoning skills are,   if you touch fire your skin will burn (and don't give me that "but   people can walk on hot coals!" bull. There's a difference between the   transfer of heat through conduction and training one's body to deal   with the agonizing pain of said conduction). Now when I say this, I am   not speaking a truth, I am speaking a fact. If you say "fire is not   hot," you are not lying, you are incorrect. Facts are concrete   realities that no amount of reasoning will change. When one   acknowledges a fact, they are doing just that. Facts are not   discovered, facts are not created, facts are simply acknowledged.      A truth on the other hand, is almost the opposite. Truths are those   things that are not simply acknowledged, but must be discovered, or   created. If I say "God exists," and I possess strong reasoning for the   affirmative of that statement, then God really does exist, that is a   reality. However, if another individual possesses strong reasoning for   the negative, and because of this reasoning they believe that God does   not exist, then that is also a reality. If we were to debate our   ideologies, and my reasoning appeared stronger than theirs, they may   choose to adopt my belief that God does exist. If they do, then the   existence of God is just as true as the nonexistence of God which they   believed a week ago. Truths, as opposed to fact, are much more fluid   and malleable than their empirical counterparts.   and followed by further discussion.  Then I found this . Article from above link says like below:     Facts are notes and lyrics on sheet music.  Truth is what the singer   gives to the listener when she’s brave enough to open up and sing from   her heart.   But still curious about the difference between both of them.  In our daily life, in general conversation, we generally use these both terms interchangeably. Then what is the difference? Are they synonym or have specific difference?


I have an array of arrays which I have planted in the DOM, so that I can reuse it at a later stage to transfer to the server: [["1","aaaaaa","1"],["2","bbbbbbb","2"],["3","ccccccc","3"]]  If I would like to convert it back into a Javascript array, how would I go about doing this?

What is the best way of converting a multi-dimensional javascript array to JSON?


I believe I am supposed to use a mod in this problem. I am unsure exactly how to do so. Help would be much appreciated and thanks in advance!

This is my question: Find the last 2 digits of $123^{562}$  I don't even understand where to begin on this problem. I know I'm supposed to use Euler's theorem but I have no idea how or why. Any help? Thanks


Upon reading the text of Dispel Magic it isn't clear to me whether or not the caster of Dispel Magic knows whether or not they have been successful at dispelling a higher level effect. Or even if there is a higher level effect.   In particular the caster needs to     For each spell of 4th level or higher on the target, make an ability check using your spellcasting ability. The DC equals 10 + the spell''s level. On a successful check, the spell ends.   So because of this ability check, the caster seems like they might know about whether they have succeeded at the spell or not (just like a rogue knows they succeeded at their ability check to pick a lock for example).  So does the caster know if they have successfully dispelled a spell/magical effect (for these or any other reasons)?    This is related to, but distinct from,  because my question is unconcerned about saves or immunity specifically.

Suppose a cleric casts Zone of Truth on a captured enemy. Unbeknownst to them, the enemy is a rakshasa. Zone of Truth says (PHB, p. 289):     You know whether each creature succeeds or fails on its saving throw.   But (MM, p. 257):     The rakshasa is immune to spells of 6th level or lower unless it wishes to be affected.   Assuming the rakshasa doesn't wish to be affected by the Zone of Truth spell, does the caster know this?  More generally, does a caster know when targets are unaffected by a spell they have cast, either because they have made saving throws, or because they are outright immune to the spell or its effects (e.g., casting Ray of Sickness on a shadow demon, which is immune to poison damage and the poisoned condition)?


How can I find historical flight arrival data for AF149 for September 29, 2017? I need to file a claim.

Where can I find historical data on flights, specifically Delta international flights?  I need to find out about cancellations, diversions and any other flight data pertaining on particular route at a given time.  This source has to be official and stand up to legal scrutiny.


Let $F$ be a sub-field of the complex numbers (i.e. a field of characteristic zero). Let $V$ be a finite dimensional vector space over $F$. Suppose that $E_1, E_2, \dots , E_k$ are projection of $V$ and that $E_1 + E_2 + \dots  + E_K = I$. Prove that $E_iE_j = 0$ $\forall$ $i \neq j$.     I have tried this problem for for $n = 2$ as follows:  As $E_1$ and $E_2$ are projection operators,  $E_1^2 = E_1$ and $E_2^2 = E_2$. Also since $E_1 + E_2 = I$, multiplying this relation by $E_1$ we get $$ E_1 (E_1 + E_2) = E_1 I = E_1 \Rightarrow E_1^2 + E_1 E_2 = E_1 \Rightarrow E_1 + E_1E_2 = E_1 \Rightarrow E_1E_2 = 0 $$     But what to do for the general case?

I am reading Introduction to Quantum Computing by Kaye, Laflamme, and Mosca. As an exercise, they write  "Prove that if the operators $P_{i}$ satisfy $P_{i}^{*}=P_{i}$ and $P_{i}^{2}=P_{i}$ , then $P_{i}P_{j}=0$ for $i\ne j$.''   In the context of this problem, it has been assumed that $I=\sum_{i=1}^{n} P_{i}$, where I suppose that $n$ could be infinite. I have shown that this is true in the trivial case $n=2$, but the general case has been eluding me. How should I attack this?


I've got this object which started as an SVG file.  I've used solidify and bevel on the curve but it will not bevel no matter what I do. So I converted it into a mesh.  I've converted tris to quads.  I still can't get the edge to bevel. What can I do? BLEND FILE:

I'm running Blender Version 2.83.0 (2.83.0 2020-06-03) on mac 10.15.5. I've been tinkering with modeling items and I can't make mesh modifier operations work for me.  I draw a path in Adobe Illustrator It looks like like the outline of seahorse. Export to SVG. Go blender. Import SVG convert to mesh extrude Boolean two cylinders  The last item want to do is break the edge with a bevel. It won't bevel. I've also tried to use the geometry tab to extrude the SVG curve and bevel it there before converting to mesh. However then it won't let me boolean the cylinders out. Any direction would be appreciated.


I have a string "2013-10-09 00:00:00" and I use the code below to change it to a timestamp  date_default_timezone_set($timeZone); $timeStamp = strtotime("2013-10-09 00:00:00"); //echos 1381269600   When I do   date_default_timezone_set($timeZone); date("Y-m-d H:m",$timeStamp);   I get 2013-10-09 00:10:00. This is completely strange. Why do I get this 10 minutes difference?

I have a datetime column in MySQL.   How can I convert it to the display as mm/dd/yy H:M (AM/PM) using PHP?


I know this question is duplicated  but I tried to follow old answers and didn't understanded them.   So I tried to update an it went wrong and now I have to reinstall ubuntu but I would like to keep the home files. I'm a complete beginner at upuntu and not so good with computers so if the answer could be very detailed and best with photos that would be awsome.  When I installed  I think I tried to make a partition  of the /home but trying to reinstall I didn't find it.  So when I reinstall and click on do something else I have /dev/sd1 type ext4 used 26GB with ubuntu 16.04. LST system /dev/sd5 type swap used 0 mb /dev/sd6 type ext4 used 365 GB  I need to know when I click on change what to do with everyone of them I'm details  because I didn't understand when I read the ubuntu guide to reinstalling.  Please answer with the most basic and detailed instructions possible  Thank you!!

Recently I installed Ubuntu 12.10 x64 Server Edition on my PC. Unfortunately, I attempted to install a lightweight desktop but due to the fact that I have an old graphics card, the PC does not perform so well. I am thinking of re-installing an Ubuntu version but I do not want to lose the contents in my home folder. Is there any way to do that with a Live CD?


What is the subject in the following sentence?     Who hit the ball through Mr. Brown's window?     How can we tell what the subject is in a sentence like this in terms of the grammar?

In a question like "Who hears a noise?",  is the subject of the sentence who?  I can think of a few tests for subjects like: "the subject is the phrase that inverts with the auxiliary to form a question". But this is a question and there is no auxiliary. We could say that's because it's a subject, but that would be just to presuppose that it's a subject in the first place.  I can think of tests like: "the form of the verb will agree with the number of the subject", but on the other hand who does not seem to have  fixed grammatical number, and it sometimes seems like who might actually be agreeing with noun phrases later in the sentence:   Who are the most prolific writers of our age? Who is the most prolific writer of our age?   There are also tests like "the subject is usually the first noun phrase in the sentence". But of course if we have a question like:   Who have you bitten?   ... you, not who seems to be the subject. The first noun phrase test is not very good.  I also know that some theories of grammar say that there is a gap in wh- questions that the wh- word is extracted from. So can this gap for instance be the real object of a question? If so, is [See community wiki post in the linked to question]  How can we show whether who is really the subject of my original example question? And how about other wh- words like what? Can they (also) function as subjects?


I have two list as follows (both list contains super long data):  list_1 = ["apple", "orange", "banana", ......] list_2 = [[1,0,0,0,0], [0.5,0,0.5,0,0], [0,0,1,0,0], ......]   I want to have an outcome of :  list = {"apple" : [1,0,0,0,0], "orange" : [0.5,0,0.5,0,0], "banana" : [0,0,1,0,0], .......]   What I want to do is like putting list_1[0] to list_2[0], list_1[1] to list_2[1] and so on.  Is there a way to do automatically pair the data up no matter how long the datasets are ?  Thanks

Imagine that you have the following list. keys = ['name', 'age', 'food'] values = ['Monty', 42, 'spam']  What is the simplest way to produce the following dictionary? a_dict = {'name': 'Monty', 'age': 42, 'food': 'spam'}


This is getting old, sometimes I answer a Q and it feels like doing tech support for my uncle or neighbor. You know, they call every few days with "one more thing".  Case:   Here, they accept an answer and thank you for the help, then come back the next day, take back the 15 rep, and change the question scope in the comments.  How can I reply to comments like this better in the future? Any suggestions on kindly asking the OP to just make a new question rather than appointing me as their personal help desk?

I'm not sure if there's already an existing term for this, so I'm inventing my own. (tl;dr: I call them "chameleon questions" because they change every time you submit or edit an answer.  If you're already intimately familiar with the phenomenon, please skip past the first set of bullet points to where I ask for recommendations.)  I think many of us have experienced this on occasion:  You open up a narrow-looking question, usually dealing with some specific error message.  The question probably contains a snippet of sloppy but not quite awful code; code indicating that the author, typically a new/low-rep user, possibly a , doesn't really know what they're doing.  I'm not trying to be condescending here, they're probably very intelligent and hardworking, but in this specific case, they're clearly in way over their head.  However, as a question, it's not really too bad.  The goal and problem are both clearly stated.  The code is formatted (sort of).  Mort was polite and checked their spelling.  The question looks answerable, although from a rep perspective* it's an obvious dead-end, it's had maybe 3 views in the past 30 minutes.  So you decide, you know what, this person took the time to write up the question properly, they deserve an answer, put on your good citizen hat and throw them a bone.  You slog through the ugly code, find the offending line, direct their attention to it and explain why it's wrong and how it needs to be fixed.  Later, they leave a comment saying that yes, that was indeed the problem and your answer helped them fix it (great!).  Oh, but, now there's another problem (uh-oh...). Something else is broken.  After letting out a long sigh, you read the comment and/or edited question, roll up your sleeves, and write up Take 2, hoping that's the end of it.  And of course it's not the end.  Now maybe the error is gone, but it's not doing what it's supposed to.  If you're anything like me, your patience is now starting to wear thin. It's lousy code and you didn't volunteer to help them rewrite their whole app.  And of course, the question still only has 12 views, and nobody has upvoted either the question or your answer, including the person you're helping, so this is turning out to be a genuinely thankless task in all respects.  Welcome to "Family Tech Support", Web 2.0 Edition.   * Which is of course just an arbitrary number that none of us care about. Not really, anyway. Not very much, at least.  So, here's where I get to my question.  At this point, do you:  Leave a comment, stating as politely as possible that you've done your best to help them answer the original question they asked, and if they have a new problem then they should start a new question?  (I did this once, and actually ended up with an accept, but I felt kind of guilty afterwards, I don't think anybody answered their 2nd question).  Bite the bullet and edit your answer a 3rd, 4th, 5th time, however many times it takes to resolve their issue, knowing full well that they may not even remember to accept the answer once you're done? (I may work for free on SO, but that doesn't mean my time is worthless.)  Just abandon the question, hoping that it will force Mort to start thinking for himself?  Something else?   I've tried all three of the above and none of them ever quite feel right. I do want to help, but at the same time there are a lot more "lucrative" questions I could be answering. And I don't mind spending a lot of time on an answer either, if the question is interesting or important to me, but debugging is dull work. I'd prefer not to reference specific questions here; I'm pretty sure that this is a shared experience, and my objective isn't to point fingers at "misbehaving" members.  I'm more looking for some practical advice on how to dig myself out of these pits of despair. Anybody have any other ideas?


Let $G$ be a region in a complex plane. Suppose $f:G\to\mathbb C$ is analytic and one-one. Show that $f'(z)$ is not zero for any $z$ in $G$.    I was trying to do the contradiction method. But I can't conclude anything. Please help

I recently saw a lecturer prove the following theorem (assuming the result that every analytic function is locally 1-1 whenever its derivative is nonzero): Let $\Omega \subset \mathbb{C}$ be open, and let $f : \Omega \to \mathbb{C}$ be 1-1 and analytic on $\Omega$.  Then $f'(z_0) \not = 0$ for every $z_0 \in \Omega$.  I got the basic idea behind the proof: we assume for contradiction that $f'(z_0) = 0$, and, assuming without loss of generality that $z_0 = f(z_0) =0$, we have (from the power-series expansion) that $f(z) = z^kg(z)$ for some analytic $g$ in some disk at the origin (i.e., $z_0$) and some $k \ge 2$. Since $z^k$ is not 1-1 in any such disk (because there are multiple roots of unity), then $f$ isn't either.  However, the proof he gave was rather awkward and technical- it involved defining three different axillary functions, even though the idea was simple, and I've since forgotten how it exactly worked.  In any case, I'm convinced there's a better way.  The problem is that I'm having trouble turning the idea into a real proof- I know that it obviously follows if $g$ is 1-1, but I'm also pretty sure that that is too strong an assumption.  Am I missing something, or does the argument just have to be more complicated?


I hope, that the question fits here. What does the picture of Warm Welcome hat represent? (I am not asking about the meaning of the hat, but the image itself.)  EDIT: It turned out to be an usánka.

I've just earned the "Warm Welcome hat" and the red star on it looks like a communist symbol. I associate this symbol on this particular hat closely with many atrocities against my country: Poland, as well as Czechia, Hungary, Slovakia, Ukraine and many others from inside the Iron Curtain.    I hope I don't get banned by this. It's just… I was really shocked to see it this morning.     Disclaimer: text below was added by a moderator, not me  Can Stack Exchange be more mindful of the symbols used when it's just about fun?


On my mobile phone everytime I ask or answer a question it asks me to fill in a reCaptcha. How can I prevent this. I am using Opera Mini 10 on a Nokia C6.

Which browsers are officially supported by Stack Exchange?  Also, what else is needed in order to use every feature of the site?


Let's assume RH was correct, and $1/2+Ki$ is any one of non-trivial zero of $\zeta$, is following problem open?  1) $K$ is irrational number  2) $K$ is transcendental number

A look at the first few zeros  $$14.134725,21.022040,25.010858,30.424876,32.935062,37.586178,\dots$$ is in accord with     Numerical evidence suggests that all values of $t$ (the imaginary part of a root of $\zeta$) corresponding to nontrivial zeros are irrational (e.g., Havil 2003, p. 195; Derbyshire 2004, p. 384).    (numbers and quote taken from ). What are the attempts to prove that all values of $t$ are irrational? Would it mean something to the distribution of primes, if one, some or plenty of rational roots $\frac{1}{2}+i\frac{q}{r}$ exist?


I'm trying to store multiple different derived classes from the same base class in a vector of pointers. Trying to call a function of one of those objects results in a segmentation fault. I haven't used inheritance very much, but I've tried every version I've been able to find and they either result in a  segmentation fault or just calls the function of the base class. I'm relatively new to C++ and haven't posted much before so please let me know if I'm sharing too much code, missing anything important, or messing up in any other respect (style, efficiency, etc.). Edit: Instead of trying to return a Random or Human, the getPlayer function now just returns an int which which indicates which type of Player to create. The new code still results in a seg fault at the same point. (excluded getPlayer since it just returns an int and can no longer be the cause of the problem.) This is where I define the base class (Player) and derived classes (Human and Random): #include <string> #include <iostream> #include <limits> #include <time.h> #include "Othello.h" using namespace std;  // Player interface to choose game moves class Player { public:     // Selects and returns a move      virtual int getMove(Othello &game) {         return 0;     } };  // User-operated player class Human: public Player { public:     int getMove(Othello &game) {         int move = 0;         bool valid= false;                  while (!valid) {             cout << "Select a move: " << endl;             cout << "-> ";             cin >> move;                          if (cin.good()) { valid = true; }                          else {                 cin.clear();                 cin.ignore(numeric_limits<streamsize>::max(),'\n');                 cout << "Invalid input. Try again.\n" << endl;             }         }         return move;     } };  // Basic bot - selects a move at random class Random: public Player { public:     int getMove(Othello &game) {         srand(time(NULL));         return ( 1 + rand() % game.n_moves );     } };  Here is the main function which results in a seg fault at the line move = players[state-1]->getMove(game): int main() {          // Select players (human, AI, random, etc.)     // players[0] is left empty to keep the index consistent with the player id     vector<Player*> players(2);     int type;     for ( int i : {1, 2} ) {         type = getPlayer(i);         if (type == 1) { players.push_back( new Human() ); }         else if (type == 2) { players.push_back( new Random() ); }     }          // Load and start the game     Othello game = loadBoard();     int state = game.getState(1); // 1 or 2 for turn, or 0 for game over          // Continue making moves until the game ends     int move;     int legal;     while(state != 0) {         game.print();         legal = 0;         cout << "PLAYER " << game.turn << endl;         while (legal == 0) {             move = players[state-1]->getMove(game);             legal = game.doMove(move);         }         state = game.getState();     }          game.print();     game.score();          return 1; }

Someone mentioned it in the IRC as the slicing problem.


My app contains a directory X.  Inside directory X all the files will be automatically generated by the scripts, but directory X needs to be there.  I have added the following to the .gitignore and it does not create an empty directory when I do the commit.  How can I get it to just create and empty directory? /myApp/dirX/somestuff.  I just need /myApp/dirX to be created. .* dirX/*

How can I add an empty directory (that contains no files) to a Git repository?


My Samsung Note 4 has been acting up lately and is now practically dead. It doesn't turn on whatever the method is. As much as I want to let it go, it holds a lot of pictures that I didn't put on my memory card that I don't think I want to disappear. I have been consulting it to numerous people and they suggested to reprogram it, which means to wipe out every single thing on it. I thought of removing the physical internal memory of the phone and put it to another Note 4 and access the pictures there, maybe even the whole phone itself.   Is there a better option to salvage my pictures? Thanks a lot :)

Phone worked perfectly. Then one day completely dead, nothing at all. It may have been that "one day" was after some time of laying around, cannot recall.  Model: Android AT&T Samsung Galaxy S3 (SGH-i747 SKU S9255)  Already tried;   Charging phone: no visual output at all, no leds Removing battery while charging: no visual output at all, no leds Removing SIM and SD card: no visual output at all, no leds Attempt to turn on: no visual output at all, no leds   I need to get our family photo's off this phone (stored on internal memory). I care less about the hardware/phone itself.  Thank you for any help you can offer!


So my company orders laptops from Dell, and as per usual ordered one downgraded from Win 10 to Win7.  In this case it is a Dell Precision 7510 with an Intel i7 and an SSD Lite On CX2 NVMe 512 GB. The SSD failed pretty quickly and Dell sent someone to replace it. I think he also replaced the Motherboard. Unfortunately trying to boot our Win 7 Pro image failed because this machine has only USB 3, and the standard Win 7 image has no drivers for USB 3. So the guy left before we got to installing Windows, which I now regret. I added USB 3 drivers to the image and got as far into the install as selecting a drive but no drive is found –and it invites me to load a driver for mass storage.  But I cannot find a driver for any Lite On SSD. I’ve never seen an SSD that needed one to be added, actually so not sure if this is the right way to tackle this. I have seen suggestions of using another make of driver and I downloaded a load of different ones including Intel on the theory that’s the chipset. In BIOS I get option for AHCI and RAID On and I tried both with same result.  It recognizes different drivers if I check ‘Hide drivers that are not compatible’, depending on RAID or AHCI. But any I can see and load still give no drive visible. DISKPART also fails to find the disk so none of the solutions which involve DISKPART are useful right now.  If it’s relevant when I go to boot options I get: Boot mode – Legacy, Secure boot: Off. Then under legacy boot it shows: M.2 PCIe SSD or Onboard NIC. Under UEFI Boot is : UEFI: CX2-8B512-Q11 NVMe LITEON 512GB. So it’s sort of showing up under Legacy Boot but sort of not properly. Can’t see anything else under BIOS that seems even vaguely relevant.   When I contacted Dell the guy said try installing Windows 10, which works fine, so he said there is no fault and it was therefore not their problem (even though it was definitely ordered as a Windows 7 machine). They also said supplying a Win 7 image was not their problem – although I tried 3 different ones, in case. Any smart people out there got a clue what to do?

I have an Asus Sabertooth Z170 motherboard, with a Samsung 950 Pro m.2 NVMe drive on it. I've heard in the past that installing Windows 7 on an NVMe drive was a significant amount of work. Its now August 2016, is it still difficult? I've seen updates from Microsoft saying they've added support for NVMe in Windows 7.  Can I just download Windows 7 from Microsoft () and put it on a USB drive and install?  Is it harder than that?


How can i find words with doubled letters(e.g. progress, tool and so on) in text using regex?

I am looking for a regex that will find repeating letters. So any letter twice or more, for example:  booooooot or abbott   I won't know the letter I am looking for ahead of time.   This is a question I was asked in interviews and then asked in interviews. Not so many people get it correct.


How does subsurface scattering RGB radius work? Right now, I have a light source and instead of RGB, it is showing cyan magenta and yellow. I don't know why this is happening and I have read documentation and watched video tutorials and nothing seems to have shown the problem or even properly explain how to use this tool.

The Subsurface Scattering in Principled BSDF is a bit confusing:  Where can I find some recommended presets (like in other software)? What is the main difference between SSS Color and Radius? (Technical papers don't help very much, I'm not an engineer)


I want to create a simple one page PDF document with some figures (png) plus some text (no maths) and would like to avoid installing the full 2GB MikTex for that. Is there some minimal small sized teX package designed for such small projects? Thanks,

I am using LaTeX to document a system I am developing. The system is itself a development environment which will be generating documentation. What is the minimum distribution I need to include in my system in order for users to produce documents from the generated LaTeX code.  What is the minimum distribution that will meet the first requirement, and satisfy all the license conditions of all distributed material (I assume this will be larger).  In response to comments:  OS Window XP Distribution MikTex + TexNic centre


Denote $p_j := j\text{th prime}$ and $S(n)\:=\sum_{j=1}^n p_j$ (The sum of the first $n$ primes).     Is it known whether $S(n)$ is prime for infinite many $n$?   OEIS gives the sum of the prime numbers  upto $10^{18}$, which is $12,212,914,292,949,226,570,880,576,733,896,687$, being a $35$-digit prime.  The relative low growth rate of $S(n)$ (of order $n^2\ln n$) is another heuristic argument that the answer to the given question should be yes.

Starting from 2, the sequence of sums of all consecutive primes is:  $$\begin{array}{lcl}2 &=& 2\\     2+3 &=& 5 \\     2+3+5 &=& 10 \\     2+3+5+7 &=& 17 \\     2+3+5+7+11 &=& 28 \\     &\vdots& \end{array} $$ If the $n^\text{th}$ prime is $P_n$, then we can write $S_n=\sum_{i=1}^n P_n$.  I conjecture that the sequence $S_n$ contains an infinite number of primes.  I doubt I'm the first person ever to think this, but I cannot find reference to the idea, nor can I conceive a proof, nor a disproof.  Computationally, it can be verified that     $$S_{13,932}=998,658,581=P_{50,783,012},$$ and the sequence shows no sign of slowing down.  Can you prove the sequence $S_n$ contains an infinite number of primes?


I am trying to scrape the number of photos statistic from a Facebook Group (currently 432,780) at:  I have copied the relevant xpath and used the following formula in Google Sheets: =importxml("https://m.facebook.com/groups/553511078046085?view=info","//*[@id='u_0_y_OX']") However, it doesn't work and keeps showing the error message "imported content is empty" Any ideas what I'm doing wrong?

Google Sheets has several import functions   IMPORTDATA IMPORTFEED IMPORTHTML IMPORTXML   Sometimes the above functions returns errors like #N/A Imported content is empty and would like to be sure that there isn't a problem with the resource content to be imported.  How do I know if these functions are able to get the content that I looking to import?  I know that there also exist IMPORTRANGE but that function only is able to import content from Google Sheets spreadsheets


I would like to print the entire array sPack[]. I take in up to 500 values into sPack then I sort in ascending order. My median value is off so I would like to print what my sort method is doing so I can see if it is an issue with my median method or my sort method.  int [] sPack = new int [500]; int i = 0; String input = br.readLine(); while(input!=null && i<500 && input.length()!=0)//(!input.isEmpty()&& i<500)// {   sPack [i] = Integer.parseInt (input);   i++;   input = br.readLine(); } sort(sPack, i); double Var = calcVariance(sPack,i); System.out.println (sPack); //this is where i need help***************<==

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


The following might be standard textbook question, but not being a native speaker I am unaware of the origin.  In ancient English, as well as in other Germanic languages, questions were posed exchanging the position of subject and verb, a structure that still holds nowadays for auxiliary and modal verbs.   Examples:   why speakest thou? how goes it?   whereas nowadays such ordinary verbs require the "do" as in "why do you speak?" and "how does it go?", respectively. Likewise for the negative forms, that used to be defined accompanying the verb with the negative not (as in speak not of the subject and similars).  When was the "do form" introduced in the English language (and how come)?

When and why did we start using auxiliary verbs, particularly "do", to ask questions and make negatives?


This may be a very silly question, but when I'm looking at the current value of a 'per second' counter in PerfMon, for example SQL Statistics\Batch Requests/sec - how is that value actually measured?  Let's say I use PowerShell's Get-Counter method to return a result for a specific server, as follows:  (Get-Counter -ComputerName $server -counter $countername -SampleInterval 1 -MaxSamples 1).CounterSamples.CookedValue   And this returns: 32  How can that value actually be contextualized? Is it an "average of 32 batch requests per second in the last x minutes"? Or is it "in the last second there were 32 batch requests"

I have verified through SQL Server Profiler that my request per-second are around 30 request/s as is corroborated by SSMS Activity Monitor but sys.dm_os_performance_counters is reporting hundreds of millions/s.  Any idea what might be causing this gross discrepancy?  Query:  SELECT     RTrim(LTrim(object_name)) as object_name,     RTrim(LTrim(counter_name)) as counter_name,     cntr_value FROM     sys.dm_os_performance_counters  WHERE      instance_name IN ('', '_Total')     and counter_name IN (         N'Batch Requests/sec'         , N'SQL Compilations/sec'         , N'SQL Re-Compilations/sec'         , N'Transactions/sec')   Results:  object_name counter_name    cntr_value SQLServer:Databases Transactions/sec    191721399 SQLServer:SQL Statistics    Batch Requests/sec  242955426 SQLServer:SQL Statistics    SQL Compilations/sec    42048371 SQLServer:SQL Statistics    SQL Re-Compilations/sec 1200947


On almost all keyboard layouts I have ever seen, the 0 is to the right of the 9, rather than to the left of the 1 (the  is the only exception I can think of; it has 0 between 9 and 2):  1234567890  Why is the 0 to the right of 9 rather than to the left of 1 — the latter seems more logical, as it means all digits are in increasing order?  The modern answer is, of course, because people are used to it.  So the real answer must lie in history...

On a typical keyboard, why is the 0 in the number row next to the 9 instead of the 1?  This seems like a question which should have a straight-forward answer, but the only one I could find is  which has two instances of entirely unsourced speculation as answers.  (0 as 10, and because 0 is rarely at the start of a number)  To complicate things, the  article adds that      0 and 1 were omitted to simplify the design and reduce the manufacturing and maintenance costs; they were chosen specifically because they were "redundant" and could be recreated using other keys. Typists who learned on these machines learned the habit of using the uppercase letter I (or lowercase letter L) for the digit one, and the uppercase O for the zero.   One might speculate that the 0 is placed where it is because of it's proximity to the O, but since the 1 was added down at the other end (nowhere near the I), it would have made just as much sense to put 0 down there too.  Almost every keyboard layout I've seen listed on wikipedia is this way, even the ones which don't use latin script at all. Only the Hungarian one (thanks, Gildas) puts 0 before the 1.  This may be due to inheriting from latin-alphabet keyboards, though.  Anyone have an explanation for this oddity?  Or specific sources backing up the yahoo theories?    Edit: Based on everyone's answers, I've done more research and come up with what I think is the logical explanation.  I don't have specific sources to cite, though, so I'm still open to an "official" answer, if anyone has one.


I would like to avoid anonymous visiting to my wordpress site. It is focused to a very small community from our neighborhood. I would like to force users to register themselves by facebook or regular login.  Is that possible somehow?   I tried to find a plugin for it, but I was not able to found anything.

How to redirect non-logged users requesting for a specific page/URL to another page/URL and display a message like "for members only".  I know its quite easy to code using !is_user_logged_in() function but i don't know how to code it because i am a newbie to WordPress.  Care to tell me the file to put the code also.


I see numbers in parentheses after program names and it confuses me. For example, perldoc mentions that perl grep is "similar in spirit to, but not the same as, grep(1) and its relatives."  What does the (1) signify? In there a grep(2)? Where is this documented?   I see manual pages that refer to the numbers as well but I don't know what the numbers mean or how to use them. I can't type "man grep(1)" for instance.

So, for example, when I type man ls I see LS(1). But if I type man apachectl I see APACHECTL(8) and if I type man cd I end up with cd(n).  I'm wondering what the significance of the numbers in the parentheses are, if they have any.


I use ubuntu gnome, it gives error while starting. I have to restart samba with command, but i dont know how to reach terminal before logging in, any advices?

Using  to install Oracle Java I accidentally restarted on Step 10 and now I can't get past the login screen. I'm wondering if there is a way to access terminal without logging in and finish the last 4 steps? After I try to sign in it takes me right back to the sign in screen.


I was looking up the difference of the speed of electricity versus the speed of light online and I found that the speed of electricity can approach (up to 90% of) the speed of light at 186,000 miles per second or approximately 300,000 kilometers per second. But, the comparison that I saw was with light traveling in a vacuum versus electricity traveling via a medium such as a cable. So, my question is what would be the speed of electricity in an absolute vacuum? Please help me understand.

I'm in a freshmen level physics class now, so I don't know much, but something I heard today intrigued me. My TA was talking about how at the research facility he worked at, they were able to accelerate some certain particle to "99.99% the speed of light". I said why not 100%, and I didn't quite understand his explanation, but he said it wasn't possible. This confused me. Since the speed of light is a finite number, why can we go so close to its speed but not quite?  Edit: I read all the answers, and I think I'm sort of understanding it. Another silly question though: If we are getting this particle to 99.99% the speed of light by giving it some sort of finite acceleration, and increasing it more and more, why cant we increase it just a little more? Sorry I know this is a silly question. I totally accept the fact we cant reach 100%, but I'm just trying to break it down. If we've gotten so close by giving it larger and larger acceleration every time, why cant we just supply it with more acceleration? And how much of a difference is there between 99.99% the speed of light, and the speed of light? (I'm not really sure if "difference" is a good word to use, but hopefully you get what I'm asking).


i am stuck on this question for a while and i'm not sure about it  i need to calculate the radius of convergence for: $\sum _{n=1}^\infty d(n)x^n$  what i did:  since i cannot use the root test or check the next eleent against its previous(ratio test), i think that to find the radius of convergence i need to check for the upper limit(sup).  so what i did is this: if n=1 we get that its one, so while going to a very large n, i think that $d(n) < n$. if this is correct, then tha radius should be: $\frac{1}{R}=\limsup_{n \to \infty}d(n) ^ {\frac{1}{n}}$. however, i don't know how to calculate it.  am i correct? how can i calculate the radius of convergence here?

I came across this question.  Let $d(n)$ denote the number of divisors of $n$. Let $$\nu(z) = \sum\limits_{n=1}^{\infty} d(n) z^{n}$$ Whats the radius of convergence of this power series. We also have to show that $$\nu(z) = \sum\limits_{n=1}^{\infty} \frac{z^{n}}{1-z^{n}}$$  Regarding the divisor function, we have Dirichlet's formula in hand. But will that help!


When using Nano text editor, how can I display line numbers so I can see the lines that I am getting error messages about.  I have a lengthy program and am getting an error message for line 95 and 125 for example.

Is there a way to tell nano to automatically show line numbering each time I open a file?


i am recently come from windows 7 to ubuntu 14  how can the PC hibernate in ubuntu system ?  i tried a command but it doesn't work will thanks

In Ubuntu 12.04 and newer, . How can I enable this back?


My dad was going for a surgery on his shoulder this month and he invited me over to assist him for awhile. I have a 3-year-old child, so I applied for the both of us and we were refused a visa.   I had already been given visas to the UK when I was in school, so I thought it was the same process. My husband is in Italy now, and he was the sponsor. When I sent the documents, I did not translate any of them. Also, I ticked unemployed instead of self employed.   My dad is out of surgery and alone in the apartment and not able to move much. I have my own business and I will never jeopardize my child's life for anything. Next summer, we will be on holidays in Italy.  Can I apply with all the necessary documents? How soon can I apply?

Many of the UK visa refusals we see here share a common pattern and the prevailing reasons refer to V 4.2 (a) and (c).    I do understand that, while the applicants may describe very different individual circumstances, there's a consistent pattern and, broadly, fall into specific categories:    Credibility (lifestyle, lack of ties, visit history, lies & omissions) Funding (insufficient funds, provenance of funds, funds parking) Sponsorship (family, friends, employer)   Question: What most commonly triggers a UK visa refusal where V 4.2 (a) and (c) are given as the grounds?  Secondarily: Given that there is a clear pattern, to what extent are these refusals predictable? Does sponsorship make a difference? Is there a set of personal circumstances, however abstract, where a refusal is all but guaranteed? For example, why do those we see here on TSE who sought entry for the PLAB or British Army appear to be refused with a common theme? Is there a uniform shortcoming or is it just discrimination?   PLAB: What is about applications for a visa, for the purpose of sitting the Professional and Linguistic Assessments Board (PLAB) exam, that seem to invite refusals. After all, the test is given so that international medical graduates can show that they qualify to practise medicine in the UK. The first part, PLAB 1, can be taken in centres outside of the UK. However, PLAB 2 can be taken only in the UK. Why can't you can't get a visa just to sit the exam, promising that you'll leave immediately after?    British Army: Since Commonwealth citizens are eligible to apply online to join, even those who don't reside in the UK, why is it so difficult to get a visa just to attend an interview to see whether you are suitable? Even with an invitation from the Army, such visa applications seem to be unsuccessful. Isn't a career in the British Army a valid reason?     Lastly:  After such a refusal, what approaches would increase the chance of a successful application?


I am reading about Win32 programming with C/C++ and came across a page which defines the WinMain as:  int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow);   I understand most of this, except I do not understand where did the part WINAPI come from?  I know that this is a macro for a calling convention. That's not what I am seeking clarity on. My question is not on calling conventions.  When I look at Microsoft's documentation on , and I read through optional parts of a function declaration, I don't see any mention of including a calling convention at any place in the function declaration. So where exactly does Microsoft in their documentation speak about including calling conventions in a function declaration?

I'm learning about Win32 programming, and the WinMain prototype looks like:  int WINAPI WinMain ( HINSTANCE instance, HINSTANCE prev_instance, PSTR cmd_line, int cmd_show )   I was confused as to what this WINAPI identifier was for and found:  #define WINAPI      __stdcall   What does this do?  I'm confused by this having something at all after a return type.  What is __stdcall for?  What does it mean when there is something between the return type and function name?


I am found below example and I can't understand the calculation of the return statement (return (kk, ll);).  Is there anybody who explain to me about the calculation of the return statement?  #include<stdio.h>  int addmult(int ii, int jj) {     int kk, ll;     kk = ii + jj;     ll = ii * jj;     return (kk, ll); }  int main() {     int i=3, j=4, k, l;     k = addmult(i, j);     l = addmult(i, j);     printf("%d %d\n", k, l);     return 0; }

How does the comma operator work in C++?  For instance, if I do:  a = b, c;     Does a end up equaling b or c?   (Yes, I know this is easy to test - just documenting on here for someone to find the answer quickly.)  Update:  This question has exposed a nuance when using the comma operator.  Just to document this:  a = b, c;    // a is set to the value of b!  a = (b, c);  // a is set to the value of c!   This question was actually inspired by a typo in code.  What was intended to be  a = b; c = d;   Turned into  a = b,    //  <-  Note comma typo! c = d;


My laptop has a decent i5 processor, 8 gigs of ram. I have dual booted it with Ubuntu 16.04 but it takes too long to boot.  Some information:  systemd-analyze   returns,  Startup finished in 2.630s (firmware) + 2.417s (loader) + 4.067s (kernel) + 44.125s (userspace) = 53.240s   and  systemd-analyze critical-chain   returns,  The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character.  graphical.target @44.100s └─multi-user.target @44.100s   └─mysql.service @37.972s +6.127s     └─network.target @37.951s       └─wpa_supplicant.service @40.980s +419ms         └─basic.target @33.530s           └─sockets.target @33.529s             └─snapd.socket @33.504s +17ms               └─sysinit.target @33.495s                 └─apparmor.service @22.549s +10.945s                   └─local-fs.target @22.437s                     └─boot-efi.mount @22.080s +356ms                       └─systemd-fsck@dev-disk-by\x2duuid-4C19\x2dC7DF.service @11.596s +10.419                         └─dev-disk-by\x2duuid-4C19\x2dC7DF.device @11.575s lines 1-17/17 (END)   First, is this performance normal? How might I make improvements? Thanks.

I have seen many videos that make Ubuntu faster, but these methods only make desktop performance faster.  I am looking to make my computer boot faster. Is their anything I can do to make Ubuntu boot significantly faster?


When im using text area the output format is different from input format eg:   input as :   hi,  hello world.  it outputs :  hi,hello world  what changes i want to make this code  to get a format as input.  <html> <head> </head> <body> <form method="get" action="textarea.php"> <pre> <textarea name="name"> </textarea> </pre> <input type="submit" name="submit"> </form> <?php if(isset($_GET['submit'])) {     $name=$_GET['name'];     echo $name;  } ?> </body> </html>

How do I save user-entered line breaks from a <textarea> HTML element to a database?  It always removes the line breaks.


Sorry for my English, I'm French and  I have  tried a lot (even with SIP disabled) but nothing works. I'm kind very desperate since I’m not sure how I would set up screen time to limit my children’s usage of the Pre-installed apps. The reason why I need to do so, is that my kid waste time in stead of studying. Is there a guide how to set this up?

There are some preinstalled apps that came with my laptop that I know I wil never ever use.   Apps like "Notes", "Stickies", "Game Center", etc.. that were preinstalled in my Macbook Pro are apps that I don't plan on ever using and it's taking up too much space in my Application Folder.  Are there any ways to remove them? Please note that I have already tried dragging it to the Trash bin, but it won't even go to the Trash bin. It' just stuck in my computer forever.


I want to prove that $\lambda$ is an eigenvalue of $A$ if and only if $\lambda$ is an eigenvalue of $A^T$. We know that $\det(A)=\det(A^T)$, but how can I apply it to $\det(A-\lambda I)$? Thanks a lot!

Let $ \sigma(A)$ be the set of all eigenvalues of $A$. Show that $ \sigma(A) = \sigma\left(A^T\right)$ where $A^T$ is the transpose matrix of $A$.


Instead of having captions such as Caption 2.1, Caption 2.2 and so on, I would like to have Caption 1, Caption 2 etc. in my document, e.g. the captions which are not related to the chapters. I am using the following code:  \begin{figure}[!ht]   \centering     \includegraphics[width=0.7\textwidth]{prizemlje}     \caption{Osnova prizemlja \cite{5}} \end{figure}

Some document elements (e.g., figures in the book class) are numbered per chapter (figure 1.1, 1.2, 2.1, ...). How can I achieve continuous numbering (figure 1, 2, 3, ...)?  And vice versa: Some document elements (e.g., figures in the article class) are numbered continuously. How can I achieve per-section numbering?  \documentclass{book}% for "vice versa" variant, replace `book` with `article`  \begin{document}  \chapter{foo}% for "vice versa" variant, replace `\chapter` with `\section`  \begin{figure} \centering \rule{1cm}{1cm}% placeholder for graphic \caption{A figure} \end{figure}  \end{document}   Bonus question: Is it possible to adjust the numbering of the sectioning headings themselves? Can I, e.g., switch from per-chapter to continuous numbering of sections in the book class?


I haven't experienced any issues when 13.10 is installed on my desktop but after installing it on my laptop (Fujitsu LifeBook) the brightness settings seem to default to the dimmest setting and even though I manually slide it to the brightest it will always default each time I reboot.  Is there a fix for this?

To work around  (changing LCD brightness via hotkeys impossible), I'd like to have one command line query for increasing and one for reducing the brightness of my LCD. I could then map a hotkey to each one of this queries.  The problem is: I don't know how to increase and reduce the LCD brightness on the command line. Do you?


I read recently that the galactic "flatness" of the Milky Way is due to the rotation of the galaxy combined with a vast stretch of time.  Yet, I also read where 1) the Milky Way rotates once every 225 million years, and 2) the Milky Way is about 12 billion years old.  This means -- all other things (such as galactic collisions adding substantial amounts of mass) being equal -- that the Milky Way has only rotated approximately 53 times in its existence.  How is that enough time to flatten the disk?

Question: As we know, (1) the macroscopic spatial dimension of our universe is 3 dimension, and (2) gravity attracts massive objects together and the gravitational force is isotropic without directional preferences. Why do we have the spiral 2D plane-like Galaxy(galaxies), instead of spherical or elliptic-like galaxies?   Input: Gravity is (at least, seems to be) isotropic from its force law (Newtonian gravity). It should show no directional preferences from the form of force vector $\vec{F}=\frac{GM(r_1)m(r_2)}{(\vec{r_1}-\vec{r_2})^2} \hat{r_{12}}$. The Einstein gravity also does not show directional dependence at least microscopically.  If the gravity attracts massive objects together isotropically, and the macroscopic space dimension is 3-dimensional, it seems to be natural to have a spherical shape of massive objects gather together. Such as the globular clusters, or GC, are roughly spherical groupings , as shown in the Wiki picture:     However, my impression is that, even if we have observed some more spherical or more-ball-like , it is more common to find more-planar  such as our ? (Is this statement correct? Let me know if I am wrong.)  Also, such have a look at this more-planar Spiral "galaxy" as this NGC 4414 galaxy:    Is there some physics or math theory explains why the  turns out to be planar-like (or spiral-like) instead of spherical-like?  See also a   p.s. Other than the classical stability of a 2D plane perpendicular to a classical angular momentum, is there an interpretation in terms of the quantum theory of vortices in a macroscopic manner (just my personal speculation)?  Thank you for your comments/answers!


I said, “I will swim today only if I go to the beach if it is sunny today.” Does the “if it is sunny today” clause modify “I will swim today only if I go to the beach” or does it only modify “I go to the beach”? My guess is the former answer because an if clause has to modify an independent clause or main clause. Please let me know if my reasoning is correct or if my sentence is so ambiguous that both interpretations are valid.

If I said, "I will run, not if it is snowing, if I my shoes are comfortable." Does the "if my shoes are comfortable" modify the "I will run" clause? I agree the sentence would be clearer with the addition of "and" in place of the comma. However, without the "and" is it still clear that the "if my shoes are comfortable" clause modifies the "I will run" clause?


I am trying to change title of a visualforce page which is rendered as PDF. But adding title attribute to apex:page tag,   or even adding title in head tag,  <apex:page controller="NMAT_PaymentReciept" title="Payment Acknowledgment Receipt for NMIMS Application" showHeader="false" sidebar="false" renderAs="pdf">     As of now its showing pages Name  Please help...this is frustrating.  Thanks for time!

What can I do on a Visualforce page that is a renderAs="pdf" that will result in the name of the file that shows up when the user clicks Save As... to not be the name of the Visualforce page.  The page is generated via a GET request coming from clicking a custom button.  Below is some code that is representative of the PDF.   <apex:page standardController="Account" extensions="AccountPdf"           showHeader="false"           sidebar="false"           renderAs="PDF"          title="AccountReport.pdf"          contentType="application/pdf#AccountReport.pdf"          <head>              <title>AccountReport.pdf</title>          </head>          <apex:outputText value="Hello World"/>  </apex:page>   The browser bar does not have the title value in it and when the user clicks Save As... the name of the file is the name of the Visualforce page (e.g., myPageName).  If I remove the renderAs="pdf" the file downloads automatically with the correct file name due to the contentType, but the actual content type doesn't appear to be a PDF.


We have a stored procedure that we run regularly. It blows up the size of TempLog.ldf from nothing to 150 GB in the course of 3-4 hours. What's going on and why is it so big? TempDB.mdf is a constant 40GB. That's a fine size, and it never gets bigger. The Recovery model for TempDB is set to Simple. AutoShrink is off.  The procedure does not use any explicit transactions. It works through roughly 500 chunks of data. Some are very small, only a couple hundred rows. Some are very large, 1 - 5 Million rows. One chunk has 16 million rows.   For each chunk of data the procedure:   Reads its rows from a persistent table into a #temp table 1.  Copies those rows from #temp_table_1 into another #temp table 2, processing them as it goes.  Creates a non-clustered index on #temp_table_2. Does a number of updates on #temp_table_2.  Deletes rows from #temp table 2 where a specific column contains a null. Copies rows from #temp_table_2 into a "persistent" table.   Truncates the #temp tables.   As I said, the size of TempLog.mdf consistently stays at 40GB which is fine. I need to know why TempLog.ldf gets so large and what I can do to mitigate the problem. I tried adding a manual checkpoint for TempDB at after the #temp tables have been truncated. That doesn't appear to make a difference.  Questions:   What goes on in TempLog.ldf? Does creating an index on a #temp table take a lot of space in TempLog.ldf? Why isn't any of this space released from TempLog.ldf when the procedure ends? Can I inspect the contents to determine what's taking so much space? Any other ideas about what might be going on?

I would like to know how to identify the exact query or stored proc which is actually filling up the transactional log of TEMPDB database.


Mary says, " I'll wait until you make your decision."  Which would John say? A) "She said she'd wait until I make my decision." B) "She said she'd wait until I made my decision." If they are both OK, is there any difference?  Thank you in advance.

How can I transform the following sentence into reported speech? Let's say my colleague said to me:      I will practice until I reach my goal   If I want to say it in reported speech, should it be      He said he would practice until he reached his goal   or      He said he would practice until he reaches his goal   Should I shift tenses completely, or should I leave the "reaches his goal" part in present tense?


Banach space $E$ is the direct sum of its closed subspaces $L$ and $M$. $M$ is finite dimensional. $T:E \rightarrow E$ is a bounded linear operator. I'm asked to prove that $T(E)$ is closed iff $T(L)$ is closed.  I have only learned the open mapping theorem and closed graph theorem, and have no idea how to prove that the image is closed. Any hint will help. Thank you.

Let $B$ be a Banach space, $H,K$ be closed subspaces and let $K$ be finite dimensional.  Suppose $B = H\oplus K$ and $T:B\to B$ is a bounded linear operator.  How do I show that $T(B)$ is closed $\iff$ $T(H)$ is closed ?


When I was read about the elliptic curve cryptography I found some definition about domain parameter of  elliptic curve like the follow. But I did not understand something $p$: prime number. $a, b$: field elements, they specify the equation of the elliptic curve $ E$ over $F_P$, $y^2  ≡ x^3+a • x+b  $ $G$: A base point represented by $G= (xg, yg)$ on $E (F_P)$ $n$: Order of point $G$ , that is $n$ is the smallest positive integer such that $nG = O$. $h$: cofactor, and is equal to the ratio #E($F_P$)/$n$, where #E($F_P$) is the curve order. My question What's diffrence between  $n$ & #E($F_P$)? also I think two are same value. because #E($F_P$) is Curve Order where The number of points on the elliptic curve is called its curve order. and when we do #E * $G$ = $O$. Is this right or not right?

In cryptography, an elliptic curve is a group based on a finite field $GF(p^k)$; this group has $n$ elements on it, and we work on a prime-sized subgroup of size $q$.  We denote the value $h = n/q$ as the cofactor of the curve.  My question is: why would we ever want to consider using a curve which has a cofactor $h>1$?  Or, in other words, why would we consider using an elliptic curve that had a composite number of points?  After all, the discrete log problem can be solved in $O(\sqrt{n / h})$ time; if we were to select a curve with $h>1$, we are deliberately making this problem easier.  Now, if $h$ is small, we're not making it much easier; if (for example) $p^k \ge 2^{256}$ and $h \le 4$, this would still appear to be an intractible problem.  On the other hand, I don't know if we want to make the attacker's job any easier than necessary, unless we gain some other benefit from it (perhaps making some other attack harder, or gaining some computational efficiency).  So, is there any benefit for using a curve with a cofactor > 1?


I have two tensors (12 x 128 x 10) samples. The second tensor contains some samples of the first tensor and other samples. Similar to that example with matrices:  A = [1 2 3 4 5 6; 11 12 13 14 15 16] B = [4 5 6 7 8 9; 14 15 16 17 18 19]   When I intersect of my two tensors, I get ~1080 values that are the same, which is expected since:  column 1 to 78 from tensor 2 = column 50 to 128 from tensor 1        tensor2 (:,1:78, 1:10) = tensor 1(:, 50:128, 1:10).   However, I do the mean of the two tensors in the third dimension  m1 = mean(tensor1, 3) m2 = mean(tensor2, 3)   Then the values of the mean are different. I expect:  m2 (:, 1:78) = m1(:,50:128).   But the values are different. Why is this happening?

I am writing a program where I need to delete duplicate points stored in a matrix. The problem is that when it comes to check whether those points are in the matrix, MATLAB can't recognize them in the matrix although they exist.  In the following code, intersections function gets the intersection points:  [points(:,1), points(:,2)] = intersections(...     obj.modifiedVGVertices(1,:), obj.modifiedVGVertices(2,:), ...     [vertex1(1) vertex2(1)], [vertex1(2) vertex2(2)]);   The result:  >> points points =    12.0000   15.0000    33.0000   24.0000    33.0000   24.0000  >> vertex1 vertex1 =     12     15  >> vertex2     vertex2 =     33     24   Two points (vertex1 and vertex2) should be eliminated from the result. It should be done by the below commands:  points = points((points(:,1) ~= vertex1(1)) | (points(:,2) ~= vertex1(2)), :); points = points((points(:,1) ~= vertex2(1)) | (points(:,2) ~= vertex2(2)), :);   After doing that, we have this unexpected outcome:  >> points points =    33.0000   24.0000   The outcome should be an empty matrix. As you can see, the first (or second?) pair of [33.0000 24.0000] has been eliminated, but not the second one.  Then I checked these two expressions:  >> points(1) ~= vertex2(1) ans =      0 >> points(2) ~= vertex2(2) ans =      1   % <-- It means 24.0000 is not equal to 24.0000?   What is the problem?    More surprisingly, I made a new script that has only these commands:  points = [12.0000   15.0000           33.0000   24.0000           33.0000   24.0000];  vertex1 = [12 ;  15]; vertex2 = [33 ;  24];  points = points((points(:,1) ~= vertex1(1)) | (points(:,2) ~= vertex1(2)), :); points = points((points(:,1) ~= vertex2(1)) | (points(:,2) ~= vertex2(2)), :);   The result as expected:  >> points points =      Empty matrix: 0-by-2


I am running only Linux on a Mac computer. I am working on the TTY terminal only as I have not installed GUI yet. Right now, history gives me this:  $ history     1  2016-10-05 00:25:36 grape instance status     2  2016-10-05 00:26:00 history     3  2016-10-05 00:27:10 history | more     4  2016-10-05 00:44:56 history | sed 's/.[ ]*.[0-9]*.[ ]*//' | uniq | grep -i "heroku"     5  2016-10-05 00:45:36 history | sed 's/.[ ]*.[0-9]*.[ ]*//' | uniq     6  2016-10-05 00:49:29 history | sed 's/.[ ]*.[0-9]*.[ ]*//'     7  2016-10-05 00:51:32 history | cut -d " " -f7-1000 |     8  2016-10-05 00:51:36 history | cut -d " " -f7-1000     9  2016-10-05 00:56:54 history   I want to get rid of the timestamps and index number. I want just the commands. As you can see from the history, I tried solution of : history | sed 's/.[ ]*.[0-9]*.[ ]*//' | uniq | grep -i "heroku", but it does not seem to work on TTY terminal. It removes the index numbers, but the timestamp is still there. Output is as below (I omitted the  uniq and grep command as i don't need them):  $ history | sed 's/.[ ]*.[0-9]*.[ ]*//' 2016-10-05 00:25:36 grape instance status 2016-10-05 00:26:00 history 2016-10-05 00:27:10 history | more 2016-10-05 00:44:56 history | sed 's/.[ ]*.[0-9]*.[ ]*//' | uniq | grep -i "heroku" 2016-10-05 00:45:36 history | sed 's/.[ ]*.[0-9]*.[ ]*//' | uniq 2016-10-05 00:49:29 history | sed 's/.[ ]*.[0-9]*.[ ]*//' 2016-10-05 00:51:32 history | cut -d " " -f7-1000 | 2016-10-05 00:51:36 history | cut -d " " -f7-1000 2016-10-05 00:56:54 history 2016-10-05 00:59:04 history | sed 's/.[ ]*.[0-9]*.[ ]*//'   I even tried running history | cut -d " " -f7-1000 | sort (from the comments in the linked question) but it does not remove the timestamps either.   I also tried running first solution from the link: HISTTIMEFORMAT ="";, but I get an error saying      HISTTIMEFORMAT: command not found   Is it possible to get history without timestamps in TTY?  EDIT: The solution from  did not work for me initially because of a single space. (Given solution was HISTTIMEFORMAT =""; but the space had to be removed to make it work. Otherwise I wouldn't have asked this duplicate question.

Using bash, I save my history with the timestamp.   How do print the history omitting the timestamp?   alias h=history alias g=grep -i   To find lines that I used for heroku, I type:  > h | g heroku   I'd like to unique the results without the time-stamp, naturally.  This question is somewhat related:   However, sometimes I want to see the duplicate in the history to see the context under which a command was run.


I want to buy a laptop and install Ubuntu on it. Most laptops these days are Windows 10 based, which require a UEFI secure boot, but don't require it to be unlocked.  So I can imagine that most OEMs don't turn it off.  Would I be able to install Ubuntu on a Dell/HP/Lenova computer and (at least) have it boot?

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I am having trouble understanding how to answer this question. I have a transition matrix P: $$         \begin{matrix}         .7 & 0 & .3 \\         0 & 1 & 0 \\         .2 & 0 & .8 \\         \end{matrix} $$ I've figured out the first part of the question which asked me to prove that two 1x3 matrices were stationary which I did with SP=S. But for the second part of the question it asks me to find another stationary matrix for P and it provides me with a hint. The hint is:  $$         \begin{matrix}   \\T=aR+(1-a)S, \\  0<a<1         \end{matrix} $$  I'm not sure what to do with that equation. Am I supposed to turn it into another 1x3 matrix and prove it's stationary with TP=T? Do I multiply the  equation as it is now with P and then figure out something with that result? Or do I substitute a number in for 'a' and solve for that and then multiply that result with P?

This is my first post here so I apologize if I format something incorrectly.  So I have a transition matrix P, $$         \begin{matrix}         .7 & 0 & .3 \\         0 & 1 & 0 \\         .2 & 0 & .8 \\         \end{matrix} $$ and I have two stationary matrices R and S respectively,  $$         \begin{matrix}         .4 & 0 & .6 \\                \end{matrix} $$ and $$         \begin{matrix}         0 & 1 & 0 \\         \end{matrix} $$  I was able to prove that they are both stationary matrices by showing SP=S and RP=R but the next question asks me to find $\mathbf another$ stationary matrix for P using a provided hint. The hint is  $$         \begin{matrix}   \\T=aR+(1-a)S, \\  0<a<1         \end{matrix} $$  I am unsure how to get a stationary matrix from that. Do I just multiply the R matrix by a and then multiply (1-a)S and then add the two resulting matrices together? If I do that then I end up with 1-a in the matrix and that just confuses me more. Sorry if this is supposed to be basic stuff, I always struggle with math :/


Would an observer moving with close to the speed of light ($\sim 99\%$) towards a star system that's $20$ light years away perceive the distance as being less than $20$ light-years? If yes, how much time would elapse in their frame of reference given the aforementioned speed of $.99c$ and $20$ light-years distance?

So, I'm traveling to another star 100 light years away in my spaceship. This ship has a solar sail pushed by a laser beamed from my home star system, so can achieve a velocity close to c. It's also got a robust parachute to slow down with.  I understand that if I measure light coming from my origin star, it will always still seem to be streaming past me at light speed (but will red shift as my speed increases). Light coming from my destination star also travels past me at light speed, and will become increasingly blue shifted as I gain speed.  I also understand that an observer checking on my speed at my origin or destination will always find it to be less than c.  However, will I perceive that in terms of the time it apparently takes me to reach my destination, my speed was greater than c? In other words, will it seem to take less than 100 years to reach the destination? 10 years on my watch, say. Or 1 year. Or a week?  Ie, as far as I'm concerned, while light keeps zipping past me at light speed, do I continue to accelerate unabated to an arbitrary apparent speed?  If not, how do I notice my continued acceleration being prevented?


Suppose i have directory /home/me/okay which have permission as shown below : drwxr-xr-x 1 nizarpermanahadi nizarpermanahadi 4096 Jul 24 17:39 okay  After that i tried to change it with chmod -x okay command. And now the permission had changed like this : drw-r--r-- 1 nizarpermanahadi nizarpermanahadi 4096 Jul 24 17:39 okay Now the directory only can be read or written. When i tried to read it. The terminal showed like this : ls: cannot access 'okay/dalam.cpp': Permission denied total 0 -????????? ? ? ? ?            ? dalam.cpp  I want to read the directory without executing it and see the list. Can i do that?... if yes, how to do that?

I wonder - why, when some folder has read or read-write permissions for GROUP (or other), the members of the GROUP (or other) can't access this folder?   I'm almost sure there is a logical explanation, but I can't find it. Let me give an example.  Initial circumstances  1. There are two users, called admin and guest.  2. There is a folder, called /var/www/test-dir:  $ getfacl -pt /var/www/test-dir/ # file: /var/www/test-dir/ USER   root      rwx GROUP  admin     r-x other            r-x   3. Within these permissions all users are able to access the folder:    USER    root    rwx (7) is able to access the folder. GROUP   admin   r-x (5) is able to access the folder. other   guest   r-x (5) is able to access the folder.  guest@host:~$ cd /var/www/test-dir/ guest@host:/var/www/test-dir$ ࢒    Cases  Case 1: other has r-- permissions but admin can't access the folder:  root@host:~# chmod 574 /var/www/test-dir/    USER    root    r-x (5) is able to access the folder. GROUP   admin   rwx (7) is able to access the folder. other   guest   r-- (4)  is unable to access the folder.  guest@host:~$ cd /var/www/test-dir bash: cd: /var/www/test-dir/: Permission denied      Case 2: other has rw- permissions but guest can't access the folder:   root@host:~# chmod 656 /var/www/test-dir/    USER    root    rw- (6) is able to access the folder. GROUP   admin   r-x (5) is able to access the folder. other   guest   rw- (6) is unable to access the folder:     Case 3: GROUP has r-- permissions but admin can't access the folder:  root@host:~# chmod 745 /var/www/test-dir/    USER    root    rwx (7) is able to access the folder. GROUP   admin   r-- (4) is unable to access the folder. other   guest   r-x (5) is able to access the folder.     Case 4: GROUP has rw- permissions but admin can't access the folder:  root@host:~# chmod 467 /var/www/test-dir/    USER    root    r-- (4) is able to access the folder. GROUP   admin   rw- (6)  is unable to access the folder. other   guest   rwx (7) is able to access the folder.


Python program is automatically adding additional number in float longitude. I am creating new columns "src", "des" using others in csv. Can see the line number 4 in result csv, "des" contains longitude value different from that in Dropoff_longitude. But I want the same value with as it is. No modification while making tuple.   Code:  import pandas as pd import numpy as np  def loc(x):      return (round(x[0],14),round(x[1],14))   columns=["Pickup_latitude","Pickup_longitude","Dropoff_latitude","Dropoff_longitude"] df=pd.read_csv("demo.csv") df["src"]=df[ ["Pickup_latitude","Pickup_longitude"] ].apply(loc,axis=1) df["des"]=df[ ["Dropoff_latitude","Dropoff_longitude"] ].apply(loc,axis=1) df.to_csv("result.csv",index=False)   I have added a pic of my

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


My sister and I made a really cool house. She wanted to download the world so she could have it too. Problem is, in 0.7.3 it just say "quit to menu" or whatever. How do you quit and copy the world? Where did the menu option go to copy a multiplayer world?

How do you save a joined game after the 0.7.1 update? The menus have all changed since 0.6.x and I can't find the option to save a copy of a joined world anymore. (My friend has got a diamond house on survival and I want to save it but it doesn't let me!)


I have doubt on String literal uninitialised variable html. Running version and trace are matching line number 95 is comment. public class WebviewActivity extends  AppCompatActivity  { String html;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);  } @Override protected void onResume() {     super.onResume();     generateChart(); } private void generateChart(){       html = "<!DOCTYPE html>";     html += "<head>";     ... }  } Not able to understand fully this crash. A method is in defined in NDK lib generateChart and in webview activity also with same name but different signatures. Native method is called in webview through ndk wrapper. I am confused with crash line Method.Invoke(Native method) Is this crash due to native method or Java method? And how to simulate this error to debug. java.lang.RuntimeException:   at android.app.ActivityThread.performResumeActivity (ActivityThread.java:4330)   at android.app.ActivityThread.handleResumeActivity (ActivityThread.java:4362)   at android.app.servertransaction.ResumeActivityItem.execute (ResumeActivityItem.java:52)   at android.app.servertransaction.TransactionExecutor.executeLifecycleState (TransactionExecutor.java:176)   at android.app.servertransaction.TransactionExecutor.execute (TransactionExecutor.java:97)   at android.app.ActivityThread$H.handleMessage (ActivityThread.java:2128)   at android.os.Handler.dispatchMessage (Handler.java:107)   at android.os.Looper.loop (Looper.java:214)   at android.app.ActivityThread.main (ActivityThread.java:7711)   at java.lang.reflect.Method.invoke (Native Method)   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:516)   at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:950) Caused by: java.lang.NullPointerException:   at in.multinetsystems.vedicastro.util.WebviewActivity.generateChart (WebviewActivity.java:95)   at in.multinetsystems.vedicastro.util.WebviewActivity.onResume (WebviewActivity.java:37)   at android.app.Instrumentation.callActivityOnResume (Instrumentation.java:1567)   at android.app.Activity.performResume (Activity.java:7989)   at android.app.ActivityThread.performResumeActivity (ActivityThread.java:4320)   at android.app.ActivityThread.handleResumeActivity (ActivityThread.java:4362)   at android.app.servertransaction.ResumeActivityItem.execute (ResumeActivityItem.java:52)   at android.app.servertransaction.TransactionExecutor.executeLifecycleState (TransactionExecutor.java:176)   at android.app.servertransaction.TransactionExecutor.execute (TransactionExecutor.java:97)   at android.app.ActivityThread$H.handleMessage (ActivityThread.java:2128)   at android.os.Handler.dispatchMessage (Handler.java:107)   at android.os.Looper.loop (Looper.java:214)   at android.app.ActivityThread.main (ActivityThread.java:7711)   at java.lang.reflect.Method.invoke (Native Method)   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:516)   at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:950)  Thanks

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Are the negative energy modes absorbed by the blackhole virtual exotic matter and when a blackhole hawking radiates does it produce matter and antimatter in equal amount and how do virtual particles convert to real particles after escaping the black hole

Could someone please provide an explanation for the origin of ? (Ideally someone who I have been speaking with on the h-bar)  Any advanced maths beyond basic calculus will most probably leave me at a loss, though I do not mind a challenge! Please assume little prior knowledge, as over the past few days I have discovered that much of my understanding surrounding the process as virtual particle pairs is completely wrong.


When a paragraph begins, there is an indentation in the first line. How do I know the size of the indentation? Does it depend on the size of the font? Does it depend on something else?

If no changes has been made to the settings of indentation of an article class LaTeX document, what is the width of the paragraph indent?  texdoc article in the terminal opens the Standard Document Classes for LaTeX version 2e manual. In section 6.2 Paragraphing I find the following line:  ⟨10pt⟩ \setlength\parindent{15\p@}   The  means 1pt ... so I guess this would mean that the standard indent is 15 pt at a 10 pt text size? Is this correct?


The error i receive is : Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException   String sourceURL = "jdbc:odbc:studentdb";             String driverName = "sun.jdbc.odbc.JdbcOdbcDriver";          String BName = txtDate.getText();         String AName = txtadd.getText();         String CName = txtCon.getText();         String Search = txtSeaNam.getText();        try{        Class.forName(driverName);       Connection conn = DriverManager.getConnection(sourceURL,"","");        Statement ins = conn.createStatement();       String Insert = "UPDATE student SET Address = '%"+AName+"%', ContactDetails = '%"+CName+"%', DateOfBirth = '%"+BName+"%'"               + " WHERE Name = '%"+Search+"%' and ContactDetails = '%"+Search+"%' and DateOfBirth = '%"+Search+"%'";       PreparedStatement st = conn.prepareStatement(Insert);         st.setString(1, BName);       st.setString(2, AName);       st.setString(3,CName);       st.executeUpdate();    }catch (SQLException | ClassNotFoundException e){       System.out.println(e.toString());   }   Please help with error. thanks


After I  and flagged some spam on the , for a poorly-understood reason, I went back to one of the questions I'd flagged and opened the flag dialog. There, I saw something of little importance, but of less than perfect... perfection:        I had flagged  as spam. I had not flagged the question as "not welcome in our community". And, for what it's worth, I had not added a custom flag, so... that part's right.

I recently flagged a post on SO as "Unclear what you're asking". Afterwards, for whatever reason, I clicked flag again and found this:    Is there any reason it says I've raised a duplicate flag too when I'm positive I have not? Is this a bug? The question, as of 2:56 PM UTC, 11 September, 2013, has only existed for 26 minutes and the flag doesn't exist in my flag history:    Note: There are several similar questions:       The first was never answered and the second is unrelated as it appears the person asking did, in fact, raise the flag they assumed they hadn't raised.


does anyone how does Linux decide which interpreter to call when running a text script?  i need the detail, the purpose of the ‘shebang’ and how

So, I thought I had a good understanding of this, but just ran a test (in response to a conversation where I disagreed with someone) and found that my understanding is flawed...  In as much detail as possible what exactly happens when I execute a file in my shell? What I mean is, if I type: ./somefile some arguments into my shell and press return (and somefile exists in the cwd, and I have read+execute permissions on somefile) then what happens under the hood?  I thought the answer was:   The shell make a syscall to exec, passing the path to somefile The kernel examines somefile and looks at  of the file to determine if it is a format the processor can handle If the magic number indicates that the file is in a format the processor can execute, then   a new process is created (with an entry in the process table) somefile is read/mapped to memory. A stack is created and execution jumps to the entry point of the code of somefile, with ARGV initialized to an array of the parameters (a char**, ["some","arguments"])  If the magic number is a  then exec() spawns a new process as above, but the executable used is the interpreter referenced by the shebang (e.g. /bin/bash or /bin/perl) and somefile is passed to STDIN If the file doesn't have a valid magic number, then an error like "invalid file (bad magic number): Exec format error" occurs   However someone told me that if the file is plain text, then the shell tries to execute the commands (as if I had typed bash somefile). I didn't believe this, but I just tried it, and it was correct. So I clearly have some misconceptions about what actually happens here, and would like to understand the mechanics.  What exactly happens when I execute a file in my shell? (in as much detail is reasonable...)


This question is not same as explaining Twin paradox. This question does expect that the travelling twin will age less. The question in here is what causes the travelling clock to slow down, which is verified at the end of the journey. If the cause is acceleration, then why the consecutive accelerations in opposite directions have opposite effects on clock speed.  I am looking for conceptual description, not a lot of mathematics.  Again, this is long question, please be patient.  Down voters, please share your thoughts as well.  Start -   Two twins are on earth with their clocks synchronized.  One stays on earth, the other makes a fast and long, quick round trip journey and then they compare the clocks.   Q1 - Is it expected that the trip making clock will be far behind the one that was left on earth? Obviously if it is true, then the difference will depend upon how fast and how long the trip was.  If the answer to above is true, then we know that the clock of the travelling twin did really slow down.   Doesn't this tell us that the ticking of clock was actually slowed down due to initial acceleration, then continued to run at slower rate (as compared to the one on earth), then sped up again during retardation at far end.   Suppose the travelling twin remained at 0 relative speed wrt earth for a day or so. During this day or so, both twins can verify that the clock of travelling twin is now behind, but tick rate is same during that day. Meaning the travelling clock was really ticking at slower rate.  Then the travelling twin started accelerating back toward earth. The clock of this twin would slow down again.  The retardation just before far end and the acceleration in start of return journey, are actually acceleration in same direction.  But the first part of this acceleration (retardation) sped up the clock, and second part slowed it down.   When the travelling twin reduces speed again before reaching earth. This reduction in speed again speeds up his/her clock so that the tick rate is same for both twins now. But the difference in clock times would be double of what it was noted at the far end. Consider all accelerations same rate.  Q2 - Do we really understand how the "same direction" acceleration sometimes slows down the speed and sometimes speeds them up.   But if answer to Q1 is yes, then this slow down and speeding up of clocks always seems to be equal and opposite if you consider any two consecutive changes in speed that pass through the 0 relative speed point.  Or, there is no real change in tick rate, and the slowdown is just relative and perception? And when the travelling twin comes back to earth, its clock will show same time as that of the other twin?

The paradox in the  is that the situation appears symmetrical so each twin should think the other has aged less, which is of course impossible.  There are a thousand explanations out there for why this doesn't happen, but they all end up saying something vague like it's because one twin is accelerating or you need general relativity to understand it.  Please will someone give a simple and definitive explanation for why both twins agree on which twin is younger when they meet for the second time?


In a real parallel glass slide(with two prisms imagined to be touching each other to form a parallel glass slide), The ray of light should pass through the Z in between without any dispersion or change in direction because the density in both of the prisms is the same(and they are touching each other). So Newton's experiment won't help in explaining this because in it, there is a vaccum(or air) in between and hence the change in direction of light. I hope that you are getting me, if not I'm ready to elaborate more.  [In case anyone is wondering that I did post a Q about dispersion earlier too, then that is true - but I did not get the answer of the question that I really meant to ask and hence this, I hope that you guys will help me better understand this.]

The question pretty much sums up what I need to know. Why is it that light only gets dispersed into a spectrum when travelling through two non-parallel sides(like a prism) and not through something like a glass slide with parallel slides.  And how does this experiment(an experiment conducted by Newton) explain this? Because this is what is in my school textbook.


I want to install Ubuntu in dual boot with windows 8.1 in my Acer V3-572G-75CA. The partition situation is the following:  A. 600MB: recover partition  B. 300MB: system EFI partition  C. 914GB: Windows 8.1 partition  D. 15.83GB: recover partition  Of course I have to disable UEFI boot for start the Ubuntu Live USB. But then? I can create an extended partition for / and /swap, but I need to free a primary partition, isn't it? Can I delete partition A and/or B?

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I have the following nginx configurations:  server {      listen 80;      charset     utf-8;     client_max_body_size 5M;      location /severbat {          root /root/severbat/dist;         try_files $uri /index.html;     }      location /swagger {         root /root/av/swagger-ui-dist;         try_files $uri /index.html;     }  }   And I files /root/severbat/dist/index.html and /root/av/swagger-ui-dist/index.html exist. But if I open url  I see nginx greetings page instead of index.html  However if I serve files under / it works:  location / {     root /root/severbat/dist;     try_files $uri /index.html; }   nginx-acesss.log:  2018/10/03 09:32:44 [debug] 23052#23052: *519 trying to use file: "/swagger" "/root/av/swagger-ui-dist/swagger" 2018/10/03 09:32:44 [debug] 23052#23052: *519 trying to use file: "/index.html" "/root/av/swagger-ui-dist/index.html" 2018/10/03 09:32:44 [debug] 23052#23052: *519 internal redirect: "/index.html?" 2018/10/03 09:32:44 [debug] 23052#23052: *519 rewrite phase: 1 2018/10/03 09:32:44 [debug] 23052#23052: *519 test location: "/severbat" 2018/10/03 09:32:44 [debug] 23052#23052: *519 test location: "/api" 2018/10/03 09:32:44 [debug] 23052#23052: *519 using configuration "" 2018/10/03 09:32:44 [debug] 23052#23052: *519 http cl:-1 max:5242880 ... 2018/10/03 09:32:44 [debug] 23052#23052: *519 content phase: 17 2018/10/03 09:32:44 [debug] 23052#23052: *519 http filename: "/usr/share/nginx/html/index.html"

I've got a pretty much default sites-enabled set up in my nginx on debian squeeze and i'm now trying to get it to serve up my munin graphs on myhost/munin/  Heres the location i've added to the config         location /munin             {                     root /var/cache/munin/www/;                     index index.htm index.html;             }   And here is the error I recieve:              2012/07/09 23:52:03 [error] 3598#0: *13 "/var/cache/munin/www/munin/index.htm" is not found (2: No such file or directory), client: 93.*.*.*, server: , request: "GET /munin/ HTTP/1.1", host: ""   This set up used to 'just work' in apache. I'm new to nginx so a bit lost as to why its adding the extra /munin when looking for the path. Any advice?


Currently it is quiet cumbersome to come to do reviewing on the mobile app. IMHO especially reviewing is something people could / would do in every free minutes they have e.g. due the meeting or waiting time on the doctor. By putting a link or icon prominently on the entry site, it would enhance the reviewing activity.

I'm using the official Stack Exchange mobile app for iOS or Android, and  My app crashed! It doesn't look good on my new smartphone. It won't run after I updated my device. I noticed another bug. I have an idea for a new feature which is currently not in the app.  How do I report bugs with or request features for the iOS and Android apps? Also:  I've used the built-in functionality of the app to report a bug or submit a feature request. Did I do the right thing? The app prompted me to post on Meta after an error occurred. Should I post about it here? I'm wondering why the latest version is from 2017. I've heard rumors that the apps are no longer supported; is that true? I can't find the app on my device's app store anymore! Where did it go?     We get a lot of bug reports from users about the mobile apps, which are unsupported, and at the moment, there is no centralized Q&A pair for those to be closed as duplicates of (the relevant answers are spread across multiple unrelated questions). This question is an FAQ proposal, to serve as a directly-related duplicate target for those questions.


When a question is migrated, the user can no longer edit or delete their comment(s). Would be worth fixing unless that's by design?

When a question is migrated to a SE site that I'm not registered to, I can't claim ownership of my comments. An example question:   I registered only after the question was migrated and can't delete my comments. I always like to perform some garbage collection of noise comments made by me. (like on the example question)  Would it be possible to claim ownership of comments in this scenario? Is this a bug?


I have submitted two papers in a top-tier applied mathematics journal. The first one is a short paper and the second one is a full paper. After 7 months the short paper and after 8 month the full paper got major revision. For the short paper I submitted the revised paper after 5 months. Finally, this paper got rejected after 7 months after I submitted the revision. Therefore it was under review for (7+5+7) months i.e. around 1.5 yr including the time I took for revising the paper. For the second paper I submitted the revised paper after 5 months. After this 5 months have passed. Therefore it is under review for (8+5+5) months i.e. 1.5 year. Will it be ok if I politely ask the editor about the acceptance chance of the full paper. One week back I asked the editor, he told me that they are waiting for one review. After that they will send the decision. Is it ok to request the editor whether he can confirm its acceptance chance ? If they want to reject reject now only, so that I can send to other journals. I will be applying for some jobs now. I need to know this information urgently. I am concerned because from the first round reviews I am very much hopeful about its acceptance. If I pressurize them they may reject it.

I'd just submitted a manuscript to  Journal on Mar. 1st, 2015. Right after 1 month, its status changed to Under Review. I just waited up to Jan. 2016 and send a letter to editor-in-chief to clear the status of the paper and any potential problem due to this delay. He did say this after that 10 months!:     you are right with your criticism. However your paper deals with   research topics, where only a few of roboticist are familiar with.   Hopefully we can get now the final required review. Sorry for the   inconvenience.   Now, 2 extra months are passed, yet the paper's status is still Under Review.  They should have considered responsibility regarding the case. They could easily announce us about their inability to find any interested reviewer for the manuscript, and we would find the other journal. I'm frustrated a little bit. As a matter of fact, I am reluctant to withdraw the submission as they have wasted my time, NOTICEABLY, over the last year. I wonder if they have completely neglected it.   Is there any way to handle this case, and ask them POLITELY and REASONABLY, leading to the finalization of this manuscript's situation?  Thanks  Edit: After 2 weeks from sending an email to the editor about the manuscript, he has not still replied.


If ANOVA tests the homogeneity of means then why the test statistics involves the standard deviation ... F=MSSE/MSST only involves variance ... is there anyone who knows the logic behind it?

Introduction to Statistical Learning defines the F-statistic as follows: $$\frac{(TSS - RSS) / p}{RSS / (n - p - 1)}$$ I am trying to interpret this formula intuitively - the numerator looks like the $ESS$ per regressor, and the denominator looks like the $RSS$ per observation. This does not seem like an apples to apples comparison; can anyone explain why it makes sense?  They also say that the expectation of the denominator is equal to the variance of the irreducible error if the linear model assumptions hold (I get this, as the denominator is really the Residual Standard Error, which is an unbiased estimator). They also say the numerator is equal to the variance of the irreducible error if the null hypothesis is true. Therefore the F-statistic will be close to 1 if the null hypothesis is true.  But if you let p = 1, that is, apply the F-statistic to single linear regression, it becomes:  $$\frac{TSS - RSS}{RSS / (n-2)}$$  According to the book, if the regressor has no explanatory power, the F-statistic should be close to 1. But if you imagine a data set where the coefficient on X is 0 (i.e. no explanatory power), $TSS$ will be equal to $RSS$, so the numerator and hence the F-statistic should be 0, not 1 as they claim. What is going on?  Furthermore, if you accept that the F-statistic is 1, as they claim, then $(TSS - RSS) = RSS / (n-2)$, which means $ESS = RSS / (n-2)$. If you think of the F-statistics as comparing explained vs. unexplained variation, this does not seem like a fair comparison since this decomposition makes it the ratio of TOTAL explained variation summed across ALL observations vs. the unexplained variation PER observation. Again, what am I missing?  I am just trying to make sense of it in a layman way, apologies if I am missing something obvious.


What is that makes some objects transparent while some are opaque objects.?  While considering the atomic theory of matter every thing is made of atoms. Glass as well as wood.   I was recently studying the photon absorption and emission theory which somewhat explained different refractive indeces. At that time I thought about this.   For instance, take example of Carbon allotropes ; diamond and graphite - both made with carbon atoms  If bonding is considered : there are many solids analogous to diamond   Then what factors decide opaqueness, transparency and translucency of objects?

Once I asked this question from my teacher and he replied "Because it passes light.". "And why does it pass light?" I asked and he said, "Because it is transparent.".  The same question again, Why glass is transparent? Why does light pass through it, while for opaque objects, it does not?


I'm trying to make an account but the google account making choice isn't there. So I tried to make a Pokemon club account but it says the email u you used to make an account can't be created.  Please tell me what to do.


Unfortunately, I had a late-night doubt recently, which meant (that I realized later on) I wouldn't probably get many replies (). I got just one reply, but I need more input from the experienced community of sysadmins at ServerFault.  I do not have enough rep. to offer a bounty and feature the question. What should I do under circumstances like this? Asking the same question again, but in different tone, is one. But is it considered spamming? Please advise.  EDIT: Thanks for the quick answers. I normally edit my questions many times for the sake of clarity, but I never realized that I was actually bumping them. LOL!

I asked a question almost as soon as I got my account. I got a few decent answers, but none of them helped solve my problem. The question has long since become buried by newer questions, and there's still no accepted answer. Unfortunately, because there are quite a few answers with votes, to a casual observer it probably looks like the question was answered and I just neglected to mark an answer as accepted, and the system does not consider it "unanswered".  Or, I asked a question that was a bit more difficult to answer. After waiting for some time, I received no answers, little or no comments, and only a few views. The question does show up in the "unanswered" list, but no one has answered my question.  In either case, what's the protocol for me to try to get this question answered?  I see several options:   Post the question a second time, possibly linking to the original, to get attention for the original question. This is encouraged on sites like Reddit.  However, it's probably not appropriate here, since we're encouraged to check for duplicates and not submit a question that's already been asked by someone else, so this probably falls under that heading. Wait for some kind of wiki-like talk page to be implemented, then post a plea on the talk page for input and hope that activity on the talk page bumps up the question. Edit the question, but do nothing further on the Stack Exchange site. If I edit my post to say that I haven't accepted any of the current answers but am looking for more, then the question might get answered eventually by people browsing through old questions to find something they can answer. Post the question on other sites, but link to my original question on Stack Exchange. People will either answer here, or they'll answer on the other site and I can post the accepted answer here myself.  This might be considered spamming, so it might be better to do this without the link.      For more information, see the "" page in the .