How to use more than 10 tab stops in bmatrix or other amsmath matrix environments?

I'm using bmatrix environment from the amsmath package, and I'm trying to do something like this:  \documentclass{article} \usepackage{amsmath}   \begin{document}      \begin{equation}          \begin{bmatrix}              1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11\\          \end{bmatrix}     \end{equation}  \end{document}   However, pdfLaTeX returns an error: "Extra alignment tab has been changed to \cr", and in the output the extra element is moved to the next row. (If I remove one element, then it works perfectly fine). I guess this means that I've hit some hard limit on the number of tab stops in a matrix. Is there a way to change this?  The elements in the matrix are short and could fit perfectly on a single row.


Prove $\lceil(3 + \sqrt{5})^n\rceil$ is divisible by $2^n$ for all natural numbers $n$

This sub-question is part of a larger question:     If $S_n = \left(3 + \sqrt{5}\right)^n + \left(3 - \sqrt{5}\right)^n$, show that $S_n$ is an integer. Also prove that the next integer greater than $\left(3 + \sqrt{5}\right)^n$ is divisible by $2^n$.   I was able to prove the first part easily using induction, but for the second part, I have no clue. If I use induction, I get stuck with the ceil function, which, for me, is difficult to manipulate.  How do I prove the second part?


i got a problem with hashset, I cannot remove a hashset, and here is the code  //take stopword list from file     public void stopWordList(){     openFile("D:/ThesisWork/Perlengkapan/stopword.txt");     while(x.hasNext()){          String a = x.nextLine();             a = a.toLowerCase();             stopWords.add(a);     }  }     //the method to remove stopword public void stopWordRemoval(){     stopWordList();             //if the word in the streams set is equal to stopword, it should be removed     for(String word:streams){         for(String sw:stopWords){              if(word.equals(sw)){                 streams.remove(word);                                    }         }     }   But, it gives me an exception, it says like :   Exception in thread "main" java.util.ConcurentModificationException, could anyone help me? thanks :)


How to use different workspaces on Ubuntu 14.04?

I heard something about having multiple work spaces on Ubuntu 14.04 and was curious about it.


I plugged Seagate 1 TB external hard disk into my computer and used Diskpart to check the detail information of disk. I can correctly select the USB drive. However, when I type detail disk in Diskpart, I receive an error message: there are no volumes. Why and how to fix this error?   Hint: Hard disk does not show up anywhere except in Device Manager.  Edit: The issue started after I plugged disk into my android phone then back into pc.It does not appear in   or in .Ony it appears in


I have external hard drive with some data (movies, music, apps, etc.) and I am wondering whether I can use it as bootable HDD to install windows from it, I have installer on my second PC and I am not sure if the fact I have other data on this external HDD may cause any problem when installing Windows using it? I am trying to install one of the following: Windows 7 Ultimate Windows XP Professional  preferably the solution(s) should apply to both, because not yet decided which one I will use.  Thanks in advance for any help :)


Reputation counters for SO and MSO not in sync?

SO says: 89008     MSO says: 88948    Shouldn't SO and MSO be fully in sync?


I'm confused, perhaps unnecessarily by which term to use:     What programs is company X involved in?     OR     What programs are company X involved in?


JavaScript - While loop - odd numbers exponentiation

I found some problem with JavaScript exponentiation While loop code:    var x = Number(prompt("X:")); var y = Number(prompt("Y:")); var count = 1; var power = 1; while(count <= y){  power = power * x;  console.log (x + " to the power of " + count + " is: " + power);  count++; }    This is simple mathematical formula X^Y.  In case of X=5 and Y=25 it's going well till Y=23. It looks like there is some problem with X odd numbers. Eg. X=3 and Y=35. Wrong result at Y=34. Missing "1" during multiplication. Can someone explain why it happend?


A word/phrase to describe this type of person

I'm looking for a word or phrase to describe someone who thinks that their perspective is the only one, or is the universal fixed norm against which all other perspectives are judged. They think that if they have never personally experienced something, it thereby doesn't exist.   An example is an older heterosexual white man who thinks that oppression hasn't existed in 100 years.  I'm looking for a better descriptor than "ignorant" or "narrow-minded." Thank you.


Multivariable logistic regression analysis and EPV (events per variable) in clinical journals?

Need guidance, I am not new to reading and appraising articles in clinical journals but I do feel am very new to understanding regression (if at all) after sifting through discussions here!  EPV is very important in modeling but many clinical papers published, perform (mostly) logistic regression analyses using multiple predictor variables with EPV < 5.  Then, a table is produced showing e.g. 10 variables whether each was statistically significant or not after multivariate analysis.  Is this right?  At the end of the day, odds ratios are exponentiated coefficient, and if coefficients are biased, so would your conclusions?  Edit: (Taking Scortchi's advice to elaborate) A good EPV is important as shown in the article quoted below (Villinghof & McCullough) and this (I am sure I miss many others):  Modern modeling techniques are data hungry: a simulation study for predicting dichotomous endpoints, by: Tjeerd van der Ploeg, Peter C. Austin, Ewout W. Steyerberg BMC medical research methodology, Vol. 14, No. 1. (22 December 2014), 137, doi:10.1186/1471-2288-14-137.


systemctl --user not available for www-data user

systemctl --user seems to be working fine for the desktop user:  dev@dev-VirtualBox:~$ systemctl --user > /dev/null dev@dev-VirtualBox:~$ echo $? 0   But when running the same command under the www-data user I get an unexpected response  dev@dev-VirtualBox:~$ sudo su www-data -s /bin/bash www-data@dev-VirtualBox:~$ systemctl --user > /dev/null  Failed to connect to bus: No such file or directory  www-data@dev-VirtualBox:~$ echo $?  1   How to enable systemctl --user here?  Running Ubuntu 16.04


I can't access my Gnome terminal after I installed Python 3.6 & 3.7

I tried changing my locale and also configured Python 3 alternatives. Nothing worked, but I can access the terminal after getting into file explorer. Error message for Gnome terminal:


I want to download BitTorrent Sync to synchronize my Android and PC.  Question #1  What's the difference between download from  or ?  Since I'm not interested in register myself on Google Play, can I download an APK file from any site and run it with some sort of "double click" over the name of the file, in the same way as in Windows?   Question #2  After download a file where do I save it? In the smartphone RAM? In the SD Card?  Thank you


Is it possible to move one feature in front of another in the same layer?

Is it possible to move feature in front of another? If I have smaller polygon and I draw larger polygon over it, is there a way how to move the smaller one in front? Is it possible in QGIS or better in PyQGis?


Can someone please help me proof this theorem. So far I assumed towards contradiction that there exist three consecutive odd natural numbers that are primes P, P+2, and P+4.   Theorem: 3, 5, 7 are the only three consecutive odd natural numbers that are prime.


Legal issues around using real players names and team emblems in an open source game

I'm writing a sports management simulation game. Like most sport management games, it makes heavy use of statistics. I would like to use real players, teams and league names.  i) Am I running the risk of getting into legal battles if I should use the real names? ii) Also what about team colours and emblems etc?    Update Much thanks for all the input!


I have the following data set and I applied logistic regression and my model is given below.  $logit(\pi_i) = -60.71 + 34.27*Dose_i$ I know that $e^{34.27}$ gives the odds ratio, but don't know how to interpret this. Thoughts please


Ready to use leaderboard service. Is any?

I'm looking for ready to use thirdparty leaderboard service where player's achivementes and scores can be placed. I'd intagrate it into my game to allow players push scores and locate themselves in the tables of tops. It would be nice whether anybody experienced share some points with me.


I'm an avid photographer and used bunch of cameras and memory cards that didn't given me any problem like this. Yesterday night when i was transferring files from the SD card to my Laptop, the power supply goes down accidentally and since then, I can't see any of my files stored in there. Moreover, whenever I try to access the stored files, it given me some kind of error messages i.e. Format the drive first!!   I don't know what the hell this is but I need the stored files back. I've found in previous threads that using recovery software could be your last resort. Fortunately, I've found few useful but none of them could actually recover those photos. Stellar Photo Recovery is the tool I've tried to recover photos and luckily, it is showing all my photos there but recovered files can't be open??  If you guys have some better suggestions, please do share it.  P.S. Please, I need the answer immediately or as soon as possible. I've to prepare the presentations for today meeting.   Thanks!!


It is often considered a punishment to send thieves, rapists, bastards etc. to the Wall for serving in the Night's Watch. Also there is a list of rules to follow like not fathering children, etc. Apart from that there is a danger of ranging in the wild (e.g. wilding attacks, the Others, other creatures, etc.). In spite of this there are some people who deliberately take the Black.   My question is: What are, if any, the positive benefits of joining the Night's Watch?   (Other than getting away from a society that treats you unfairly if you are a bastard)


Increase space between lines of glossed text, gb4e

I'm using gb4e in report class. I'd like to format the glossed examples created using gb4e. There are three lines in my glossed example: The original text and the gloss, which are presented in one block, and the translation, which is set off from the original text and gloss.  At the moment, there is a gap between the original text/gloss block and the translation, which is good. But when the original text is longer than one line, the text wraps round and starts again on the next line, with no gap between the new line and the preceding lines of original and glossed text.  Is there a way to increase the space between the lines of original and glossed text when they wrap around the page? I've looked through the documentation, but I can't see anything.  Here is a picture of what my current output is, and what I'd like to format:    And here is a MWE:  \documentclass[12pt]{report} \usepackage{geometry} \usepackage{gb4e}  \begin{document}  \begin{exe} \ex \gll kata-kata ini terlalu panjang, tidak ada spasi untuk kata-kata ini, saya tidak tahu harus bikin apa ka \\ word-\textsc{redup} this too long \textsc{neg} exist space for word-\textsc{redup} this \textsc{1sg} \textsc{neg} know should do what \textsc{tag} \\  \glt `These words are too long, there isn't enough space for these words, I don't know, what I should do?' \end{exe}  \end{document}


Using Model to equally distribute points, spatially within known geometry using ArcGIS ModelBuilder?

Is it possible to create a model in ArcGIS ModelBuilder where you simply state number of points and an area in the form of a polygon to get the model to try and equally space out the points based on the geometry of the polygon and number of points?


Using awk, how we can remove extra spaces, where it finds more than one space? We just need to keep one space between words, as usual. The file size is 3kb.


My question is this: should passive or active perception be used for spotting traps? If you use passive, then the DM knows ahead of time whether or not a PC will spot a trap as no die roll is involved (eg. if the highest passive perception is 13, and the DM makes the spot trap DC 14, the PCs will not see it). I would like to avoid railroading PCs by knowing ahead of time which traps they will see and which they will or won't see. Another problem with passive perception is that you have a 50% chance of getting lower than your passive perception every time you make an active perception check, so you are actually better off never looking for things, and just hoping you notice them. In summary, when should I use passive perception and when should I use active perception?


How can I check is  of given parameter ?  public static void main(String[] args) {     if (isPrimitive("test")) {         System.out.println("True");     }     if (isPrimitive(1)) {         System.out.println("True");     } }  public static boolean isPrimitive(Object o) {     // Here what would I do ? }


I'm trying to get some console output in my homework. I put it in a listings environment but I want it to be centered horizontally on the page.  The only thing I get centered is the caption ;-/  \begin{minipage}{1\textwidth} \begin{center} \begin{lstlisting}[caption={Ausgabe des C-Programms},label={ggt_c_ausgabe}] a  |  b  |  q  |  u  |  s  |  v  |  t   ---------------------------------------- 78 |  21 |   1 |     |   1 |   1 |  -1  21 |  15 |   3 |   1 |  -3 |  -1 |   4  15 |   6 |   1 |  -3 |   4 |   4 |  -5   6 |   3 |   2 |   4 | -11 |  -5 |  14   3 |     |   2 | -11 |  26 |  14 | -33  ---------------------------------------- \end{lstlisting} \end{center} \end{minipage}


Covering ten dots on a table with ten equal-sized coins: explanation of proof

Note: . I have moved it here because:   I am curious about the answer The OP has not shown any interest in moving it himself     In the Communications of the ACM, , Peter Winkler asked the following question:     On the table before us are 10 dots,   and in our pocket are 10 $1 coins.   Prove the coins can be placed on the   table (no two overlapping) in such a   way that all dots are covered. Figure   2 shows a valid placement of the coins   for this particular set of dots; they   are transparent so we can see them.   The three coins at the bottom are not   needed.   In the , he presented his proof:     We had to show that any 10 dots on a   table can be covered by   non-overlapping $1 coins, in a problem   devised by Naoki Inaba and sent to me   by his friend, Hirokazu Iwasawa, both   puzzle mavens in Japan.      The key is to note that packing disks   arranged in a honeycomb pattern cover   more than 90% of the plane. But how do   we know they do? A disk of radius one   fits inside a regular hexagon made up   of six equilateral triangles of   altitude one. Since each such triangle   has area $\frac{\sqrt{3}}{3}$, the hexagon   itself has area $2 \sqrt{3}$; since the   hexagons tile the plane in a honeycomb   pattern, the disks, each with area $\pi$,   cover $\frac{\pi}{2\sqrt{3}}\approx .9069$ of the   plane's surface.      It follows that if the disks are   placed randomly on the plane, the   probability that any particular point   is covered is .9069. Therefore, if we   randomly place lots of $1 coins   (borrowed) on the table in a hexagonal   pattern, on average, 9.069 of our 10   points will be covered, meaning at   least some of the time all 10 will be   covered. (We need at most only 10   coins so give back the rest.)      What does it mean that the disks cover   90.69% of the infinite plane? The easiest way to answer is to say,   perhaps, that the percentage of any   large square covered by the disks   approaches this value as the square   expands. What is "random" about the   placement of the disks? One way to   think it through is to fix any packing   and any disk within it, then pick a   point uniformly at random from the   honeycomb hexagon containing the disk   and move the disk so its center is at   the chosen point.   I don't understand. Doesn't the probabilistic nature of this proof simply mean that in the majority of configurations, all 10 dots can be covered. Can't we still come up with a configuration involving 10 (or less) dots where one of the dots can't be covered?


In the triangle ABC, the point P lies in the third of the segment AB near point A, the point R is in the third segment PB near the point P, and the point Q lies on the cutting line BC so that the angles PCB and RQB are equal. Determine the ratio of ABC and PQC triangle.  Thank u in advance.


How can I upgrade Mac OS without the administrator password?

I recently received an old iMac secondhand.  I have no way to reach the original owner. I am trying to upgrade the OS software, but the prompts demand the administrator's name (which is auto-filled) and password (which I do not have).  I understand why these security features are in place, but is there any way in the world for me to access Admin. privileges without the password?


Why is a javascript function unaccessible from another script file?

I have a problem I've been searching SO for answers to, but nothing seem to do it for me. I've referenced a question that mimics my problem but the solution still don't solve my problem.    My problem is as I've mentioned similar. I can't access a method inside a script file from another script file. These are my codes:  page.js  $(document).ready(function () {     $.getScript('script.js').done(function () {         $('#build').append(literals.test()); // $('#build') is a span tag in the HTML-file.     }).fail(function () {         console.warn('Unable to load script file.');     }); });   script.js  (function ($) {     var literals = {             test: function () {                 return 'Hello world!';             }         }; })(jQuery);   This still returns the following error even though I've built it almost exactly the same way as in the answer of the referenced question.  Uncaught ReferenceError: literals is not defined at Object.<anonymous>   What am I doing wrong here?


Can anyone tell me what kind of insect (if it is one) is this...!! Or is it the pupa of some insect?  Well I don't think that the whole big thing is the insect itself, it appears to be just a kind of protection or shelter which moves along with the tiny little thing that keeps on popping out and going it so as to move. Location:  India


If $n = p_1^{a_1} ... p_r^{a_r}$ the set of nilpotents of $\mathbb{Z}_n$ is $(p_1 p_2 ... p_{r-1} p_r)\Bbb Z_n$

Suppose $n = p_1^{a_1} ... p_r^{a_r}$ where $p_i$'s are prime integers and $a_i$'s are positive integer.  (a) Show that the set of nilpotent elements in $\mathbb{Z}_n$ is $(p_1 p_2 ... p_{r-1} p_r)$, the ideal generated by the element $p_1p_2 ... p_{r-1} p_r$.  (b) Find a necessary and sufficient condition on $n$ such that $\mathbb{Z}_n$ does not have any non-zero nilpotent elements.  My attempt:  (a)Let x be a nilpotent element in $\mathbb{Z}_n$. Then $x^k = n$ for some $k > 0$.Note that $x \neq 1$. Since $Z_n$ is a UFD, $x =  p_1^{b_1} ... p_r^{b_r}$, where $b_i > 0$ and so $x^k = p_1^{k b_1} ... p_r^{k b_r} = p_1^{k b_1 - 1} ... p_r^{k b_r - 1}(p_1 ... p_r) \in (p_1 ... p_r)$. Hence the set of nilpotent elements is a subset of $(p_1 ... p_r)$. On the other hand, for all $x \in (p_1 ... p_r)$, $x = z_1 \cdot p_1 ... p_r \cdot z_2$ for some $z_1 = p_1^{c_1} ... p_r^{c_r}, z_2 = p_1^{d_1} ... p_r^{d_r} \in \mathbb{Z}_n$, so $x = p_1^{c_1 + d_1 +1} ... p_r^{c_r + d_r+1}$. Let k be an natural number such that $k(c_i+d_i+1) >a_i$ for all i. Then we have $x^k = p_1^{k(c_1 + d_1 +1)} ... p_r^{k(c_r + d_r+1)} = p_1^{a_1} ... p_r^{a_r}(p_1^{k(c_1 + d_1 +1)-a_1} ... p_r^{k(c_r + d_r+1)-a_r}) = 0 \in\mathbb{Z}_n$. Hence the $(p_1 ...p_r) \subseteq$ the set of nilpotent elements in $\mathbb{Z}_n$. Therefore $(p_1 ...p_r) =$ the set of nilpotent elements in $\mathbb{Z}_n$  (b) $a_i = 1$ for all $i$. If $a_i = 1$ for all i, then it is obvious then $\mathbb{Z}_n$ does not have any non-zero nilpotent elements. Now I just need to show that if $\mathbb{Z}_n$ does not have any non-zero nilpotent elements, then $a_i = 1$ for all $i$. Proof by contradiction: Suppose there exists some $a_i$ > 1. Then $p_1...p_r < n$ is non-zero a nilpotent element.


Can't find Windows 10 after installing Ubuntu

I wanted to install Ubuntu alongside Windows 10 as dual boot. But after installing Ubuntu in grub menu, I can't find Windows 10 and I don't have any access on my hard drive even on Ubuntu. I can not unmount it. I have tried many commands on terminal but I couldn't fix Windows and I have not access to anything on my laptop. And also for installing some apps via terminal it says can't locate this app.


I'm interested in getting a basic physical understanding of how Earth's magnetic field is generated. I understand that it's a "dynamo" type of effect, driven by convection currents in the molten outer core. These currents cause charges to move, and this generates the field.  However, what I can't find a good explanation of is why there is a separation of charges in the first place. Presumably, moving neutrally charged molten iron would have the same effect as moving any other neutrally charged thing, i.e. it wouldn't create a field.  And presumably, if the fluid wasn't moving then it would become neutral pretty quickly, since molten iron is a good electrical conductor.  So am I right in thinking that the charge separation is the result of positive feedback, in that an intial deviation from neutrality would generate a field, and this would (somehow) cause a greater separation of charges, resulting in a kind of self-maintaining charge separation?  Or is there another explanation?  In either case, does anyone know of a good resource that explains the basic principles in physical terms?  I know that the interior dynamo is a very complex phenomenon, but I'd like something that gives a good physical picture of how the electromagnetic and fluid dynamical phenomena interact, rather than diving straight into partial differential equations.


Postgres version: 11  I've got 2 roles - one used for read and one for write on the same database.  CREATE ROLE reader WITH login; CREATE ROLE writer WITH login;  CREATE DATABASE thedatabase;  GRANT SELECT ON all tables in schema public TO reader; GRANT INSERT ON all tables in schema public TO writer;   Everything is fine for all the existing objects in the database, but as soon as another object is created both users will need a GRANT SELECT/INSERT to be able to perform their duties.  Is there a config to overcome this?


Which word is used for 4 wickets in 4 balls? Question about 4 in 4 not multiple hat-trick

Which word is used when bowler takes 4 continuous wickets in 4 balls? (such as hat-rick for 3 wickets in 3 balls)


For example $\prod_{2 \le j  < 1} 2^j= 1.$ How does that happen?


Concat multiple rows with dynamic table in SQL Server

I have two tables where I joined both to get the first view, after that I'd like to do GROUP_CONCAT in one column, but we don't have this function in SQL Server.  So I tried some examples here, but was unsuccessful with my SQL. Examples found always use a table to generate GROUP_CONCAT, but I didn't find any example with a SQL result.  TableA:  | CityID | MasterID | Account | +-----------------------------+ | 01 | 1234 | 1111 | | 01 | 1234 | 2222 | | 01 | 1234 | 3333 | | 02 | 1234 | 4444 |   TableB:  | Account | Item | Price | +------------------------+ |  1111   | A001 | 11,11 | |  2222   | A001 | 11,11 | |  3333   | A002 | 22,22 | |  4444   | A002 | 22,22 | |  5555   | A002 | 22,22 |   First SQL - Subselect:  SELECT *  FROM TableA, TableB WHERE TableA.AccountID = TableB.AccountID   Output:  | CityID | MasterID | Account | Account | Item | Price | +------------------------------------------------------+ | 01 | 1234 | 1111 | 1111 | A0001 | 11,11 | | 01 | 1234 | 2222 | 2222 | A0001 | 11,11 | | 01 | 1234 | 3333 | 3333 | A0002 | 22,22 | | 02 | 1234 | 4444 | 4444 | A0002 | 22,22 |   Second SQL - final view:  SELECT      MasterID, GROUP_CONCAT(Item) FROM      (SELECT *       FROM TableA, TableB      WHERE TableA.AccountID = TableB.AccountID) table01   Output:  | MasterID | Item | +-----------------+ | 1234 | A0001,A002 |


How can I draw an arrow with a 45 degree corner in tikzpicture?

In tikz, I can make an arrow connecting two nodes with straight lines and a 90 degree corner by using |- or -|. But is there an easy way to make a straight horizontal/vertical segment and then a 45 degree (or radially inward or some other angle) segment, like the red line in the figure?  \documentclass[12pt]{extarticle} \usepackage[paperwidth=7.4cm, paperheight=5.55cm, top=0cm, bottom=0cm, left=0cm, right=0cm]{geometry} \usepackage{tikz} \usetikzlibrary{shapes,arrows,positioning,calc} \tikzstyle{circle1} = [draw, circle, minimum size = 1.5mm]  \begin{document} \begin{tikzpicture}[auto, node distance = 1.2cm]         \node (first) [circle1] {first};         \node (second) [circle1, right of = first, node distance = 3.5 cm, below=2.5 cm] {second};          \draw[->, thick] (first.0) -- node [above] {$--$} (second.135);         \draw[->, thick] (first.0) |- node [below] {$|-$} (second.160); \end{tikzpicture}  \end{document}


Remove duplicate words from between lists example: We have two lists; the first list contains: a b c d  The second list contains: a b c d e f  I want to make a comparison between the first and second lists, removing the matches contained in both, resulting in this: e f  I couldn't find a solution to do that with bash, but I did find one in python:


In , the word preventative is compared (unfavourably, if my reading of the implication is correct) to preventive.  However, I have always used preventative, and can only recall hearing it in its longer form. Merriam-Webster online lists  (defining it as equal to preventive) as being first used circa 1666, and lists preventive as first used circa 1639.  Is this is a BrEng/AmEng difference? What is the etymology of these words?  (There is a  on World Wide Words, but more, or more precise, information would be appreciated.)


how do i shrink it to the size/shape of the image ? is it possible ?


Can a Wild Shaped Druid use weapons to attack?

If a 5th edition druid would transformed into an ape or creature like an ape that has has opposable thumbs like a human could they then use a weapon to attack with such as a great sword or dagger instead of the Beast usual melee attack?


How can I proof that $$\sum_{n=1}^{\infty} \sqrt[n]{3}-1$$ diverges? Which criterium should I use? I have tried integral criterium, but it was difficult to calculate. Maybe comparison test would be great, bu I have no idea with which serie should I compare.


If $n^{\alpha}$ is an integer for every $n\in\mathbb N$, is $\alpha$ a nonnegative integer?

Question:     $\alpha \in \mathbb{R}$, if $n^{\alpha}$ is an integer for $\forall n \in \mathbb{N}$, then show that $\alpha$ is a nonnegative integer.   I totally don't know how the procedure should go. Besides, I got this problem in the calculus textbook, but I cannot understand why the problem is included in the textbook.  Can you give me some simple key points to this kind of problem? Thanks for your advice.  [EDIT] I modified some expressions in order not to have various interpretations.


Indian visa for a Bangladeshi: how to deal with blacklisting?

I am a Bangladeshi. I have already travelled to India three times. The last time, I travelled to Nepal by road from India, then came back to Bangladesh. After finishing my Indian visa validity, I applied for an Indian visa, but the embassy gave me a blacklisted seal on my passport. I applied again and they did the same.   How can I withdraw this seal and get the Indian visa?


There's something wrong with this code:  \newenvironment{Tbl} {\begin{tabularx}{\textwidth}{|l|X|} \hline} {\end{tabularx}}   but this is fine:  \newenvironment{Tbl} {\begin{tabular}{|l|l|} \hline} {\end{tabular}}   Why? And how can I get the first to work?  Here is the full LaTeX file:  \documentclass[a4paper, 12pt]{article} \usepackage{tabularx}  \newenvironment{Tbl} {\begin{tabularx}{\textwidth}{|l|X|} \hline} {\end{tabularx}}  \begin{document}  \begin{Tbl} \end{Tbl}  \end{document}      latex test.tex   produces:  This is pdfTeXk, Version 3.141592-1.40.3 (Web2C 7.5.6)  %&-line parsing enabled. entering extended mode (./test.tex LaTeX2e <2005/12/01> Babel <v3.8h> and hyphenation patterns for english, usenglishmax, dumylang, noh yphenation, arabic, basque, bulgarian, coptic, welsh, czech, slovak, german, ng erman, danish, esperanto, spanish, catalan, galician, estonian, farsi, finnish,  french, greek, monogreek, ancientgreek, croatian, hungarian, interlingua, ibyc us, indonesian, icelandic, italian, latin, mongolian, dutch, norsk, polish, por tuguese, pinyin, romanian, russian, slovenian, uppersorbian, serbian, swedish,  turkish, ukenglish, ukrainian, loaded. (/usr/share/texmf/tex/latex/base/article.cls Document Class: article 2005/09/16 v1.4f Standard LaTeX document class (/usr/share/texmf/tex/latex/base/size12.clo)) (/usr/share/texmf/tex/latex/tools/tabularx.sty (/usr/share/texmf/tex/latex/tools/array.sty)) (./test.aux)) Runaway argument?  \par  ! File ended while scanning use of \TX@get@body. <inserted text>                  \par  <*> test.tex  ?


How to construct a packet containing following hexa values

I need to construct packet containing following hexa  information       01 05 00 03 D0 90 01   I need to send this data to tcp server I am confused that how can i create one packet of this data so that i can sent to server device


REML or ML to compare two mixed effects models with differing fixed effects, but with the same random effect?

Background:  Note: My data set and R code are included below text I wish to use AIC to compare two mixed effects models generated using the lme4 package in R.  Each model has one fixed effect and one random effect.  The fixed effect differs between models, but the random effect remains the same between models.  I've found that if I use REML=TRUE, model2 has the lower AIC score, but if I use REML=FALSE, model1 has the lower AIC score. Support for using ML: Zuur et al. (2009; p. 122) suggest that "To compare models with nested fixed effects (but with the same random structure), ML estimation must be used and not REML."  This indicates to me that I ought to use ML since my random effects are the same in both models, but my fixed effects differ.  [Zuur et al. 2009.  Mixed Effect Models and Extensions in Ecology with R.  Springer.] Support for using REML: However, I notice that when I use ML, the residual variance associated with the random effects differs between the two models (model1 = 136.3; model2 = 112.9), but when I use REML, it is the same between models (model1=model2=151.5).  This implies to me that I ought instead to use REML so that the random residual variance remains the same between models with the same random variable. Question: Doesn't it make more sense to use REML than ML for comparisons of models where the fixed effects change and the random effects remain the same?  If not, can you explain why or point me to other literature that explains more? # Model2 "wins" if REML=TRUE: REMLmodel1 = lmer(Response ~ Fixed1 + (1|Random1),data,REML = TRUE) REMLmodel2 = lmer(Response ~ Fixed2 + (1|Random1),data,REML = TRUE) AIC(REMLmodel1,REMLmodel2) summary(REMLmodel1) summary(REMLmodel2)  # Model1 "wins" if REML=FALSE: MLmodel1 = lmer(Response ~ Fixed1 + (1|Random1),data,REML = FALSE) MLmodel2 = lmer(Response ~ Fixed2 + (1|Random1),data,REML = FALSE) AIC(MLmodel1,MLmodel2) summary(MLmodel1) summary(MLmodel2)  Dataset: Response    Fixed1  Fixed2  Random1 5.20    A   A   1 32.50   A   A   1 6.57    A   A   2 24.77   A   B   3 41.69   A   B   3 34.29   A   B   4 1.80    A   B   4 10.00   A   B   5 15.56   A   B   5 4.44    A   C   6 21.65   A   C   6 9.20    A   C   7 4.11    A   C   7 12.52   B   D   8 0.25    B   D   8 27.34   B   D   9 11.54   B   E   10 0.86    B   E   10 0.68    B   E   11 4.00    B   E   11


The linear dependence of exponential functions

Let $\lambda_i \in \mathbb C$  $(i=1,2,\cdots,n)$ be $n$ different complex numbers and $p_i \in \mathbb C[t]$ $(i=1,2,\cdots,n)$ polynomials. If we have the relation $${e^{{\lambda _1}t}}{p_1}(t) + {e^{{\lambda _2}t}}{p_2}(t) +  \cdots  + {e^{{\lambda _n}t}}{p_n}(t) = 0$$ for all $t \geq 0$, can we conclude that all $p_i(t)=0$?


Jerk, $j(t)=\dddot x(t)$, acceleration, $a(t)=\ddot x(t)$ and velocity, $v(t)=\dot x(t)$ are derivatives of position, $x(t)$. What is the meaning of the integral of position?  For example, one could write  $$\int x \mathrm{d}t = \int x \frac{\mathrm{d}t}{\mathrm{d}x}\mathrm{d}x = \int x\frac{1}{v} \mathrm{d}x$$  which reminds the equation for .


Unable to access flash drive from within software in Ubuntu 19.04, able to access through desktop totally fine

Upgraded to 19.04 today and have run into a problem:  I am able to access my flash drive from my username folder on my desktop and copy and paste back and forth to my Documents, etc. BUT, when I am in Inkscape, Gimp, Scribus, or any other software, I am not able to access at all - It says that I do not have permissions.  I have tried sudo chown user:user media/user/device with no change.  The strangest part is that I can access it and copy and paste when accessing through the user folder on my desktop - I just can't open it from within applications. Anyone know how to fix?


Making a recursive CTE like query, but for many records

I have a table with a hierarchy ( with a recursive parentID column), for one record, I know how to get the last parent record, with the following code :  declare @Id integer  ;WITH CTE AS (     SELECT  a.[Id],             a.[ParentId]     FROM    [Area] a WITH (NOLOCK)     where a.[Id] = @Id       UNION ALL      SELECT  a.[Id],             a.[ParentId]     FROM [Area] a WITH (NOLOCK)     INNER JOIN CTE cte ON cte.[ParentId] = a.[Id] )  SELECT top 1 a.[Id] FROM CTE a WHERE a.ParentId is null   It works as long as I'm working with one id, here @Id.  But I can't find a way to do the same but for a list of Ids, without using cursors, as CTE seems to be OK only when y'oure working on one record.  Could someone point me at the right direction ?  Many thanks


sudo apt-get update not working could not lock

When I use the command sudo apt-get update I get the following error  E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable) E: Unable to lock directory /var/lib/apt/lists/ E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   Whats the meaning of this?


Markdown handles inline bold text (within a word) incorrectly

When I bold text inline like strongtext it gets parsed as italics instead of either bold or nothing.  I created the above with the following line:   **strong**text     As I understand it, inline Markdown is disabled here, so this text should really be ignored.


Switch from dvorak to qwerty when modifier key is pressed

Since I spend most of my day at a computer, I've become interested in learning to type on Dvorak. However, there's one thing holding me back: shortcuts. Shortcuts are designed to work on QWERTY, and there's a good deal of muscle memory there I am loathe to give up. Take CTRL-S for instance, normally I can do that with my left hand while my right is on the mouse, but with Dvorak S is on the right side of the board.  So here is my question: can I do something(write a script, download some software, whatever) that will automatically switch to qwerty when control, alt, or shift is pressed and then switch back when it's released? Any help is appreciated!


I have heard that a 'vitamin B17' can cure cancer, but that the medical industry never talks about it, since making it legal would cause them loss of billions. But I have never found a reliable report on whether B17 really works or not. There is a question on 'vitamin B17' deficiency as a cause of cancer (see ), however, not on 'vitamin B17' as a possible medication for cancer. What are the proposed mechanisms? And is there evidence that 'vitamin B17' really works in curing cancer?


I am trying to install a software that came with my USB interface on PlayOnLinux. I am not getting very far. How do I install software that’s on a compact disk on Linux? Oh I am using Ubuntu 13.4 by the way.


Using Windows 10 in a virtual machine. Can it be done?

I am currently running 8.1. I'd like to try out Windows 10 and if I like it upgrade. If not, I'll keep running as I am.   I've never used a virtual machine before: can Window 10 be used from a virtual machine as a "sandbox", and if so how?


Own command for \mintinline cannot handle hash character

I'm using the following command to create my own version of \mintinline:  \newcommand{\inline}[1]{{\mintinline[fontsize=\normalsize]{text}{#1}}}   This works except when I'm using the hash character. For instance:  \inline{Class#method()}   Which gets rendered with two hashes (i.e. Class##method()). When I replace my own command with \mintinline[fontsize=\normalsize]{text}{…}, everything is fine.  What am I doing wrong in my \newcommand definition?


User was removed - Why does it affect me?

Why does someone else breaking the rules and being removed cause me to lose reputation for votes they had cast on my questions or answers?


I'm in the process of debugging GLSL vertex shaders and I can't shake the feeling that I'm doing it wrong.   In general I have two strategies to make up for the lack of tracing   I stuff values into a debug color varying that I pass to the fragment shader and then try to interpret the colors. I change the vertex shader code and see what happens.   I'm thinking that ideally I could make up for the lack of tracing by writing values to a texture somehow, reading the texture from the GPU and printed the values stuffed in the texture.  My guess is that there might be way better ways. Any suggestions?


how can I make a Ubuntu installation disk? I am planning on to fresh install Ubuntu on a new hard drive.


On this problem, I'm not sure what Big O definition they are referring. How would the big o definition help show this?  Use the definition of $O$ to show that if $y = y_h + O(h^p)$, then $hy = hy_h + O(h^{p+1})$.


Does anyone actually wear eyeglasses in Star Wars?

Does anyone in The Galaxy Far Far Away wear eyeglasses? (specifically to correct for bad vision, NOT sunglasses or some special optics designed to enhance you natural senses ala whatever optics Vader's suit or Mandalorian armor provided).  (this arose out of random comment in Chat)  The question is mostly for G-canon, though I'll accept answers from T-/C- canons


HTTP 1.1 Persistent Connections using Sockets in Java

Let's say I have a java program that makes an HTTP request on a server using HTTP 1.1 and doesn't close the connection. I make one request, and read all data returned from the input stream I have bound to the socket.  However, upon making a second request, I get no response from the server (or there's a problem with the stream - it doesn't provide any more input). If I make the requests in order (Request, request, read) it works fine, but (request, read, request, read) doesn't.  Could someone shed some insight onto why this might be happening? (Code snippets follow). No matter what I do, the second read loop's isr_reader.read() only ever returns -1.  try{         connection = new Socket("SomeServer", port);         con_out = connection.getOutputStream();         con_in  = connection.getInputStream();         PrintWriter out_writer = new PrintWriter(con_out, false);         out_writer.print("GET http://somesite HTTP/1.1\r\n");         out_writer.print("Host: thehost\r\n");         //out_writer.print("Content-Length: 0\r\n");         out_writer.print("\r\n");         out_writer.flush();          // If we were not interpreting this data as a character stream, we might need to adjust byte ordering here.         InputStreamReader isr_reader = new InputStreamReader(con_in);         char[] streamBuf = new char[8192];         int amountRead;         StringBuilder receivedData = new StringBuilder();         while((amountRead = isr_reader.read(streamBuf)) > 0){             receivedData.append(streamBuf, 0, amountRead);         }  // Response is processed here.          if(connection != null && !connection.isClosed()){             //System.out.println("Connection Still Open...");          out_writer.print("GET http://someSite2\r\n");         out_writer.print("Host: somehost\r\n");         out_writer.print("Connection: close\r\n");         out_writer.print("\r\n");         out_writer.flush();          streamBuf = new char[8192];         amountRead = 0;         receivedData.setLength(0);         while((amountRead = isr_reader.read(streamBuf)) > 0 || amountRead < 1){             if (amountRead > 0)                 receivedData.append(streamBuf, 0, amountRead);         } }         // Process response here     }   Responses to questions: Yes, I'm receiving chunked responses from the server. I'm using raw sockets because of an outside restriction.  Apologies for the mess of code - I was rewriting it from memory and seem to have introduced a few bugs.  So the consensus is I have to either do (request, request, read) and let the server close the stream once I hit the end, or, if I do (request, read, request, read) stop before I hit the end of the stream so that the stream isn't closed.


Explicit holomorphic differentials on $y^3 = P(z)$ riemann surface

Let X be a compact Riemann surface of genus $g$ corresponding to the equation $w^3 = P(z)$, P is a polynomial without multiple roots and $degP = 8$ It's known that there are $g$ holomorphic differentials on this surface. How can I construct them explicitly?  If my curve was defined as hyperelliptic one, $w^2=P(z)$, then I would use $\frac{z^k \cdot dz}{w}$ for $k = 0, \cdots ,g-1$. $\frac{z^k dz}{w} = \frac{2z^k dw}{P'(z)}$, we would check that the form is holomorphic at $z \to \infty$ and $\omega \to 0$. Mention here that $deg P = 2g+2$. (I don't understand to the full how we do this). Then $\frac{z^k dz}{w}$ is well defined when $z$ is a coordinate. and $\frac{2z^k dw}{P'(z)}$ is well defined when $w$ is a cordinate.  By implicit function theorem $w$ is a coordinate everywhere where $P'(z) \neq 0$ so the second representation works and we get over the case of $w=0$.  $z$ is a coordinate everywhere where $2w \neq 0$. so the first representation works and when $z \to \infty$ then we have a double pole from $dz$ and $g+1$-ble pole from $\frac{1}{w}$  Our curve equation means that $dw = \frac{P'(z)}{3w^2} dz$ so if we try the same way it is done for hyperelliptic curve, then we should seek the answer as $\frac{z^k dz}{w^2}= \frac{3z^k dw}{P'(z)}$.   How can we check the holomorphoucity of forms more rigorously and how can I construct the forms in the case $w^3 = P(z)$


How can I capture a screenshot of an entire webpage in iPhone's Safari browser?

How to capture screenshot of entire webpage in iPhone's Safari browser like I can take in my Desktop with Help of Firefox Addon called ?


Why does bash output data instead of executing, when a script is piped?

I'm running the following script on Ubuntu 14.04:  #!/bin/bash  apt-get purge -y nginx apt-get install -y nginx  date   When I run it like cat /tmp/script | bash, apt-get starts installing, then "date" is printed (not the actual date, but the command name), then the remaining apt-get output is printed.  If however I run the script like /tmp/script, it works as expected: printing the date after apt-get finished.  Why does this happen and how can I force bash to work when being piped to the same way it does when invoked directly?


Is there a way to link users to their profile page?

Say I'm writing a post on meta, and I want to direct the reader to a specific section of their profile page. One thing one can do is to just link to the profile page of the OP who asked the question, say,  ,  and this will work for OP ─ but any future readers will be redirected to Jane's profile page instead of their own. Is there a smart way to use the SE url handling (say, something along the lines of    or something similar) which will send any logged-in user to their profile page? (And which, ideally, will carry along any additional attributes such as ?tab=badges and the like?)


How to tell a lambda function to capture a copy instead of a reference in C#?

I've been learning C#, and I'm trying to understand lambdas.  In this sample below, it prints out 10 ten times.  class Program {     delegate void Action();     static void Main(string[] args)     {         List<Action> actions = new List<Action>();          for (int i = 0; i < 10; ++i )             actions.Add(()=>Console.WriteLine(i));          foreach (Action a in actions)             a();     } }   Obviously, the generated class behind the lambda is storing a reference or pointer to the int i variable, and is assigning a new value to the same reference every time the loop iterates.  Is there a way to force the lamda to grab a copy instead, like the C++0x syntax  [&](){ ... } // Capture by reference   vs.  [=](){ ... } // Capture copies


Can protagonist be an antagonist, and vise versa?

The protagonist, is the main actor, no matter what his character is--good or bad. Normally, it centralized the story with the protagonist. On the other hand, the antagonist is the opposing character of the protagonist, with conflicting characteristics with the protagonist. What if the protagonist and antagonist change roles? Is there any special term for that? Like when either the protagonist and antagonist lead the story, having different plots, and both have the part in causing the trouble. Some stories use an interrelated parallel story plot that helps one another develop each plot. So, back to the question, how do you call that instances? How if the protagonist act as the antagonist, and vise verse for the antagonist? What's your idea about this?


Representing every positive rational number in the form of $(a^n+b^n)/(c^n+d^n)$

About a month ago, I got the following :      For every positive rational number $r$, there exists a set of four positive integers $(a,b,c,d)$ such that    $$r=\frac{a^\color{red}{3}+b^\color{red}{3}}{c^\color{red}{3}+d^\color{red}{3}}.$$      For $r=p/q$ where $p,q$ are positive integers, we can take    $$(a,b,c,d)=(3ps^3t+9qt^4,\ 3ps^3t-9qt^4,\ 9qst^3+ps^4,\ 9qst^3-ps^4)$$   where $s,t$ are positive integers such that $3\lt r\cdot(s/t)^3\lt 9$.      For $r=2014/89$, for example, since we have $(2014/89)\cdot(2/3)^3\approx 6.7$, taking $(p,q,s,t)=(2014,89,2,3)$ gives us $$\frac{2014}{89}=\frac{209889^3+80127^3}{75478^3+11030^3}.$$   Then, I began to try to find every positive integer $n$ such that the following proposition is true :   Proposition : For every positive rational number $r$, there exists a set of four positive integers $(a,b,c,d)$ such that $$r=\frac{a^\color{red}{n}+b^\color{red}{n}}{c^\color{red}{n}+d^\color{red}{n}}.$$  The followings are what I've got. Let $r=p/q$ where $p,q$ are positive integers.   For $n=1$, the proposition is true. We can take $(a,b,c,d)=(p,p,q,q)$. For $n=2$, the proposition is false. For example, no such sets exist for $r=7/3$. For even $n$, the proposition is false because the proposition is false for $n=2$.   However, I've been facing difficulty in the case of odd $n\ge 5$. I've tried to get a similar set of four positive integers $(a,b,c,d)$ as the set for $n=3$, but I have not been able to get any such set. So, here is my question.     Question : How can we find every odd number $n\color{red}{\ge 5}$ such that the following proposition is true?      Proposition : For every positive rational number $r$, there exists a set of four positive integers $(a,b,c,d)$ such that $$r=\frac{a^n+b^n}{c^n+d^n}.$$   Update : I posted this question on .  Added :  asks the case $n=3$.


How can I stop windows from rebooting after an automatic update?

I like Windows to keep itself up to date via the automatic updates, but sometimes it does that when I'm not at the computer and it's doing something critical, like downloading the latest stack overflow podcast.  How do I prevent Windows from doing the automatic reboot if I'm not there?


Linux file permissions are "-????????? ? ? ? ?" (Corrupted?)

I have recently found a very odd issue I have not encountered before. ╭─daemonslayer2048@desktop ~  ╰─$ ls -l /tmp/project                             ls: cannot access '/tmp/SpeedTest/lib': Permission denied ls: cannot access '/tmp/SpeedTest/First_Boot.py': Permission denied ls: cannot access '/tmp/SpeedTest/help.sh': Permission denied ls: cannot access '/tmp/SpeedTest/ResetDefaults.py': Permission denied ls: cannot access '/tmp/SpeedTest/Manager.py': Permission denied ls: cannot access '/tmp/SpeedTest/Maintenance.py': Permission denied total 0 -????????? ? ? ? ?            ? First_Boot.py -????????? ? ? ? ?            ? help.sh d????????? ? ? ? ?            ? lib -????????? ? ? ? ?            ? Maintenance.py -????????? ? ? ? ?            ? Manager.py -????????? ? ? ? ?            ? ResetDefaults.py  Is anyone familiar with what may be going on here? Did something get corrupted? I tried searching first but I only seem to get explanations of file permissions nothing to explain how this happened and if I can fix it. I tried setting an owner and permissions to the files but they remain unchanged. Edit: Added ls -ld of project folder. ╭─daemonslayer204@desktop ~  ╰─$ ls -ld /tmp/project/ drw-------. 3 daemonslayer204 daemonslayer204 380 Jun 17 15:56 /tmp/project/


Is it possible to add an additional static method to .Net string class so I could write:  var header = string.FormatHeader(str1,str2,str3,formatOption);


Do Chinese citizens require a visa to go to Hong Kong for less than 7 days?

I and my girlfriend (a mainland Chinese citizen) are planning to visit Hong Kong from Malaysia (where we both have MSC working visas), and will also be returning to Malaysia. I have been surprised at all of the restrictions placed on mainland Chinese citizens; it seems that there is a lot of bureaucracy required before a mainland Chinese citizen can enter Hong Kong. I am trying to find out if there is some way that she can enter Hong Kong for 3-4 days with me (a British citizen) without having to go through the hassle of trying to get a visa. After a little while reading, I found :  Chinese passport holders who are in transit through Hong Kong from another country, region or territory may be granted a stay of 7 days without the prior need to obtain an entry permit, with the condition of possession of valid Chinese passport and confirmed onward air tickets for the overseas journey. If Chinese passport holders will go for mainland China or Macau via Hong Kong, onward air tickets are not compulsory.  It seems that this could be used to allow her visaless entry to Hong Kong, as we only plan to go for 3-4 days. So here are my questions based on that 7-day exemption clause:  Does the "onward air tickets" stipulation apply when flying from and returning to Malaysia, or would it only apply if we were flying on to another country entirely? If "onwards air tickets" may not apply in that situation, does flying back to Malaysia via Macao or mainland China permit her to enter without a visa? Does simply entering mainland China without flying (for example, using the Hong Kong–Shenzhen Western Corridor to drive there) also entitle her to this entry?  I have contacted the Chinese embassy in Malaysia about these questions, but they advised me that they do not know the answer to them (which I find a little surprising).


I have a home server running Centos 7 that I'm using to host various different servers - a webserver, two Minecraft servers, and a PLEX server. Currently I have a  4TB HDD which serves as the primary storage, housing the OS and all files, and a 240GB SATA SSD which I'm using as a cache drive with Lvmcache. I've begun to run out of space on the 4TB disk, so I'm looking for a way to migrate this single disk to RAID 5 without needing to reinstall and reconfigure the OS and all software. I've chosen RAID 5 as it appears to be the best balance of price, performance, and redundancy for me.  If I were to purchase 3 additional drives and build a RAID 5 array with them, is there any possible way to clone the data and OS from the existing drive onto the array, verify that this worked correctly, then erase the single drive and join it into the array? Alternatively, should I purchase an additional, smaller drive to house the OS and clone it there, then simply use the RAID array for mass storage?  I have never previously had the occasion to use a RAID array, so I have no prior experience with them. I did find a piece of software called "Raider" that looks like it might possibly be up to the task, but, again, I have no experience with it; better safe than sorry!  Edit: output of "lvs -a -o +devices && df":


I'm trying to prove : Given a simple graph $G$ with $n$ vertices, where $n$ is even, prove that if every vertex has degree $\dfrac n2 + 1$, then $G$ must contain a (simple) $3$-cycle. A (simple) $3$-cycle is a set of $3$ (distinct) vertices, $a, b, c$ such that $ab$ is an edge, $bc$ is an edge and $ac$ is an edge.  I know there are similar ones already on here, but I can't comprehend any of the answers. This is what I have so far:  Base Case: Since the graph has to have at least $3$ vertices to have a simple $3$-cycle, the lowest possible even number of vertices is $n = 4$.   $\dfrac42 + 1 = 3$ degree (edges attached to node). This means each vertex connects to each of the other $3$ vertices since $G$ is a simple graph. Thus, any combination of $3$ vertices will be a simple $3$-cycle.  Inductive Hypothesis: Assume a simple graph with $k$ vertices, where $k$ is even, contains a simple $3$-cycle if each vertex has degree $\dfrac k2 + 1$.  Inductive Step: Since only concerned about when the graph has an even number of vertices, going to show a simple graph with $k + 2$ vertices, where $k$ is even, contains a simple $3$-cycle if every vertex has degree $\dfrac{k+2}{2} + 1$   This is as far as I get and don't know how to finish the Inductive Step (Also please feel free to let me know if I messed anything up, up to this point)


Every time I run sudo apt-get install or sudo apt-get update I get the following error message:  dpkg: irrecoverable fatal error, aborting:   files list file for package 'kde-runtime-data': Input/output error  E: Sub-process /usr/bin/dpkg returned an error code (2)   How can I fix it?


When do you use “learnt” and when “learned”?

Is learnt UK English and learned US? Is it that simple?  I’m used to using learnt, but my US spellchecker says it is wrong.


Summation to infinity with a general pattern

$$ \sum_{n=1}^{\infty} \frac{(n-1)!}{(x+1)(x+2)..... (x+n)}. $$ I tried solving it by inserting some values $\frac{1}{x+1}$ +$\frac{1}{(x+1)(x+2)}$+$\frac{2}{(x+1)(x+2)(x+3)}$ $\frac{1}{x+1}$+$\frac{1}{x+1}$-$\frac{1}{x+2}$+$\frac{1}{x+1}$-$\frac{1}{x+2}$+$\frac{1}{x+3}$-$\frac{1}{x+2}$ This gives me a hint that $\frac{1}{x+1}$ this comes n times -$\frac{1}{x+2}$ comes n-1times and so on But since the terms tend to infinity I dont find it useful so any hint? Answer is $\frac{1}{x}$


Assume you want to put a green screen overlay at the end of a longer video clip. Blender doesn't allow to do this in the compositor mode, because the overlay is placed at the beginning.  Is it possible to easily add the overlay at the end of the video?


Why is Training Neural Nets a Non-Convex Optimization Problem?

I keep hearing that neural net training is non-convex. The objective function is non-convex.  My question is:   What is the proof that the learning process is non-convex? How can you prove it is non-convex for say max likelihood training?  Is training wrt all objective functions non convex?    I am unable to find answers to these questions as most online resources never care to explain the non-convexity and take it for granted.  Thanks.


I'm a beginner in electronics, and in my free time I love making stuff with my Arduino.  As I was handling a few Bluetooth modules with my hands, I thought about static electricity discharging on the chips. I'm not very familiar with this, so I have a few questions about the topic, and I hope you could help me out to get some stuff straight in my head.   Is static electricity really so dangerous? Can I really destroy something simple like an Arduino module if I touch it? Assuming that I need a discharge in order to pass the electricity, how is this happening? Anything more I should know?


Prove that p(x) cannot have more than m zeros , where $p(x)$ is a polynominal of degree m and $p(x) ∈ \mathbb{K} [x]$ and $\mathbb{K}$ is a field

The question is as stated in the title:  Prove that p(x) cannot have more than m zeros $p(x)$, where $p(x)$ is a polynominal of degree m and $p(x) ∈ \mathbb{K} [x]$ and $\mathbb{K}$ is a field . (where the zeros are counted with multiplcities)  I am also given the hint :  Use the fact that $\mathbb{K} [x]$ is a factorial ring


Irreducibility of $1+X+\ldots+X^{p-1}$ over $\mathbb{Q}$

Show that the polynomial:  $$g(X)=1+X+X^2+\ldots+X^{p-1}$$  is irreducible over $\mathbb{Q}$, where $p$ is prime.  I am not sure how to approach this.


I recently downloaded the 2018 MacTex suite, and the following MWE fails to compile,  \documentclass{beamer} \usepackage{subfig} \begin{document} \begin{frame} Testing MWE \end{frame} \end{document}   with error code   ./Untitled.tex:3: Undefined control sequence. <argument> \@@magyar@captionfix           So, what is the "correct" way of adding side-by-side subfigures with captions now?


I am trying to prove the inequality 3*(a^3+b^3+c^3) > (a+b+c)*(a^2+b^2+c^2)  where a,b,c are positive and unequal.  RHS = a^3+b^3+c^3+ab*(a+b)+bc*(b+c)+ac*(a+c)  so the inequality reduces to proving  2*( a^3+b^3+c^3) > ab*(a+b)+bc*(b+c)+ac*(a+c)  This is where I got stuck , how to prove this ? , please help.


Parsing JSON with jQuery Mustache template

I am complete rookie to Javascript, jQuery and JSON. For the most part the JSON data is displaying correctly. I have a list of JSON array comments that is rendered in HTML. I would like to include a different background color for list items. I realize that Mustache is a logicless template but can this be achieved. Below are the codes. Any advise will be very much appreciated. Thanks in advance!  HTML:

       JSON data:          {     "comments": [     {      "name": "John Smith",      "comment": "Would like background in light gray",      "timestamp": "18-11-2013"      },      {      "name": "Jane Doe",      "comment": "Would like background to be dark gray",      "timestamp": "26-11-1991"      },      {      "name": "Amy Lang",      "comment": "Would like background in light gray",      "timestamp": "30-5-1991"      },     {      "name": "Jessica Rabbit",      "comment": "Would like background to be dark gray",      "timestamp": "23-5-1988"      }      ] }


I have a file named foo whose permissions are -rwxr-x--- root and I'm neither the user (root) nor in the group. I have another file named bar, which I want to append to foo. I've tried  sudo cat bar >> foo  but this fails with foo: Permission denied.


Evaluating $\int P(\sin x, \cos x) \text{d}x$

Suppose $\displaystyle P(x,y)$ a polynomial in the variables $x,y$.   For example, $\displaystyle x^4$ or $\displaystyle x^3y^2 + 3xy + 1$.  Is there a general method which allows us to evaluate the indefinite integral     $$ \int P(\sin x, \cos x) \text{d} x$$   What about the case when $\displaystyle P(x,y)$ is a rational function (i.e. a ratio of two polynomials)?   Example of a rational function: $\displaystyle \frac{x^2y + y^3}{x+y}$.    This is being asked in an effort to cut down on duplicates, see here:   and here:


I'd like to have a header where the current section is centered but without the section-number.  In the following example the header looks like "1 Example" but I'd like to have "Example".  \documentclass[headsepline, footsepline]{scrartcl} \usepackage{scrpage2} \begin{document} \clearscrheadfoot \pagestyle{scrheadings} \automark[section]{section} \ihead[University]{University} \chead[\rightmark]{\rightmark} \ohead[Author]{Author} \ifoot[\today]{\today} \ofoot{\thepage} \section{Example} Text \end{document}   Is that anyhow possible?


$M$ finitely generated if submodule and quotient are finitely generated.

I know this must be easy. I'm new to modules, so perhaps I must be missing  something important.     Let $M$ be an $R$-module. Show that if there exists a submodule $N$ such that $N$ and $M/N$ are finitely generated, then $M$ is finitely generated.   If the exact sequence $0 \longrightarrow N \longrightarrow M \longrightarrow M/N \longrightarrow 0 $ (where the second and third arrows are inclusion and projection respectively) splits then $M$ would be isomorphic to the direct sum of $M$ and $M/N$ and the conclusion would follow (I think). But I can't show that it splits.  Thank you.


What is the average value of the determinant of matrices in this set?

State true or false. Let $n \geq 2$ be a natural number. Let $S$ be   the set of all $n \times n$ real matrices whose entries are only $0, 1$ or $2$. Then the average of determinants of matrices in $S$ is greater than or equal to $1$.   This is how I think the answer should go, but I am not fully convinced.   False. The average value is zero. There are only finitely many matrices in $S$, and we can exhibit a one-to-one correspondence between the matrices with non-zero determinants as follows: given $A \in S$ with positive determinant, interchanging the first two columns of $A$ gives us a matrix in $S$ with negative determinant. As this function has an inverse (itself) it is bijective. Thus, the average value of the determinant of matrices in $S$ is zero.


Calculate the display width of a string in C#?

A Java version of this question was just answered, and, well, I don't know how to do this in .net.   So how do you calculate the display width of a string in C# / .net?


Decrypting two XORed compressed messages?

If through a previous attack, cipher misuse or two time pad etc. I receive $c=m_1 \oplus m_2$. Where $m_1$ and $m_2$ are compressed messages, for instance GZIPped English text documents. Can we recover something significant about the messages?   Obviously if we can guess two prefixes we can verify. Can we do more? Can something practical be done about the end if we fail to decipher the beginning? or even don't have the start of the message.   Since the messages are compressed I don't know of commom substrings except in the header nor do I know how to validate if a short fragment in the middle is plausible.


What justify the division of power series?

It is sometimes seen that people divide power series of two functions $f$ and $g$ to get the power series representation of $\frac{f}{g}$.  For example, $\tan x=\frac{\sin x}{\cos x}$, so compute $\frac{x-\frac{1}{3!}x^3+\frac{1}{5!}x^5-\cdots}{1-\frac{1}{2!}x^2+\frac{1}{4!}x^4-\cdots}$ as if it were two finite polynomials by long division, and get the quotient of first few terms, and see the pattern of what this whole power series are.  However, I haven't read any analysis books which mentioned the division of power series.  What justifies doing so? Why is it valid? Is there something we should be careful when doing this? Why we can do the traditional long divison on infinite terms polynomials?


How do I install Adobe Acrobat Reader from the repository?

How do I install Adobe Acrobat Reader in Ubuntu 14.04 using a Trusty apt repository?  This is NOT a duplicate of . In Synaptic > Repositories > Other software I enabled "Canonical Partners", but I still cannot install acroread as it is not available on my 64-bit system.  Here's the output from the console:   root@liv-inspiron:/home/liv# apt-get install acroread Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package acroread root@liv-inspiron:/home/liv# apt-get install acroread:i386 Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package acroread


How to solve the limit $\lim\limits_{n\to \infty}(1-a)(1-a^2)\cdots(1-a^n)$?

Suppose $|a|<1$ be a real number. How to solve the following limit? $$\lim\limits_{n\to \infty}(1-a)(1-a^2)\cdots(1-a^n).$$


unsigned reference to unsigned long when compile c++ program

I have a homework to deal with big number, but I cannot compile the most simple version of code. There are three files (.hh, .cpp and a test .cpp). Codes here: bignum.hh:  #pragma once  #include <cstdint>  // uint8_t  #include <iostream> // ostream  namespace bistro {     template <typename T = uint8_t>     class BigNum     {     public:         BigNum(std::size_t base);     private:      }; }   bignum.cpp:  #include "bignum.hh"  namespace bistro {     using std::size_t;      // debug     using std::cout;     using std::endl;      template<typename T>     BigNum<T>::BigNum(size_t base) {         cout << base << endl;     } }   test0.cpp:  #include "../src/bignum.hh"  using bistro::BigNum;  int main() {     BigNum<uint8_t> *b = new BigNum<>(10);     return 0; }   and I use this command to compile them:  g++ -std=c++14 src/bignum.cpp tests/test0.cpp -o tests/test0   Here is the problem:  So, where is the problem?


How do I encode specific characters to HTML in python

I'm scraping Wikipedia using BeautifulSoup4 in Python.  data = urllib2.urlopen(wikiurl) soup = BeautifulSoup(data, 'html.parser')   I then use  for link in soup.find_all('p'):    completehtml = completehtml + str(link)   To get the HTML for a few paragraphs (The for loop has a break condition using a counter that counts the number of paragraphs and then breaks if they reach the limit)  Now after this data has been scraped. I need to enter it at a website online. (I need to enter it using the HTML which is scrapped). The problem is that some of the characters such as en-dash are not in proper HTML i.e coded in HTML, which is causing symbols to appear instead.  They print out fine in Python. But when I use methods such as pyautogui or the ActionChains class to send keys and thereby enter them using the scrapped string, they are entered as symbols.  How do I fix this. Looking for a solution in Python.  EDIT: Okay, so the main issue is when non-ascii characters are in the scrapped html.  They're decoded to 'latin-1' when they're copied to clipboard or entered using the send keys method by python.  EDIT: Need to convert certain HTML entities to unicode then turn them back into HTML after replacing certain unicode substirngs.


Understanding Alexa rank, it isn't showing many of my back links?

When I check Alexa rankings for my site it says that one site is linking to my site.   Is it only showing back links? If it is then why are other website traffic checking tools like Google showing different different back links?


Is there an upper limit to temperature in thermodynamics or statistical mechanics

In many presentations of statistical mechanics where we have a system of particles having mass, such as the molecules of an ideal gas, the temperature is often equated to the average relative velocity of the particles. However no such velocity can exceed that of light. Is there therefore an absolute upper bound to temperature as well as an absolute zero?


I just started using a Blender. I was Maya and Keyshot user for years.  In Keyshot making, custom shape labels is 2 mins job, but how can I do it in Blender?  The problem is how to create these types of labels and wrap them on the objects, without having to model each piece of a label? Is this possible?


Can an Xbox One player party or voice chat with an Xbox 360 player?

I have an Xbox one and my brother has an Xbox 360.  I couldn't figure out how to join his party or invite him to mine, or even initiate a private chat.  Is this possible or am I missing something?


My hat is not showing on the chat room list of occupants

There appears to be a bug in the chatroom code - my hat is not showing on the chat room list of occupants:     It is correctly showing in the message list:    My question is not a dupe of :  As you can see one avatar has a hat and the other doesn't. They should either both have a hat or neither should have a hat ;)


What is a good wide-angle prime lens for Nikon DX (APS-C) format?

I am looking for a wide angle lens for my D90, between 12 and 18mm focal length, preferably a prime, because I like fast(er) and cheap(er) lenses.  Any recommendations ?


I keep seeing conflicting definitions of a statistic. Is a statistic a random variable such that it is a function of the random variables of a random sample? Or is it the value of the function of the random sample, after each random variable of the random sample has taken on a specific value?   $$(1) \ S=f(X_1,X_2...X_n)$$  $$(2) \ s=f(x_1,x_2...x_n)$$  I haven't been able to get any clarification for this and I've seen the term statistic describe both situations


Making the auto-hidden menu bar show up faster

I have recently switched back to Mac after Linux Mint and there is one thing I find very cumbersome:  In fullscreen mode the menu bar at the top goes into auto-hide mode, so it animatedly rolls down when I pull the mouse up to the top. My issue is that, this happens pretty slow. There is a 0.5s delay and then the animation starts to roll the menu bar down. I know it doesn't sound a lot but in practice it gets annoying when I multitask and trying get tasks done fast.   Is there a way to remove the delay and trigger the animation instantaneously?  Also, is there way to make the animation faster, or perhaps disable it?   Yosemite 10.10.04


Statement $\frac ab+\frac bc+\frac ca \ge 3$ is true for any positive $a$, $b$, $c$?

Let us have $a,b,c$ arbitrary positive numbers. Prove: $\frac{a}{b}+\frac{b}{c}+\frac{c}{a} \ge 3$ I have tried many things, but none of them seemed to work. Any ideas? (If duplicate, I am sorry, didn't see it yet) :)


How do I create my own custom PPA to share with the Ubuntu community? I am trying to create my own custom package set and I would really like to share it with the community.


I am facing a havoc situation, I choose install Ubuntu in place of Windows 10, and now I don't have any OS on my computer and Installation of Ubuntu showing error 5 every time I reached out to install it.  It shows Errno 5 input/output error message and suddenly installation gets stop.  Type of installation: through Bootable USB drive 16 Gb  Hard drive of computer: 78 Gb RAM of computer: 2 Gb  What to do?  😢😢😢😢😢 I don't have any other computer, I tried it so many times but nothing works.  Now I have a pc which is not more than a Brick.


I got an error when trying to update ubuntu using   sudo apt-get update   The response below  W: Skipping acquire of configured file 'bionic/binary-i386/Packages' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/binary-amd64/Packages' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/i18n/Translation-en' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/i18n/Translation-en_US' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/dep11/Components-amd64.yml' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/dep11/icons-48x48.tar' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/dep11/icons-64x64.tar' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: Skipping acquire of configured file 'bionic/cnf/Commands-amd64' as repository 'http://mirrors.bangmod.cloud/ubuntu bionic InRelease' doesn't have the component 'bionic' (component misspelt in sources.list?) W: GPG error: http://download.opensuse.org/repositories/home:/manuelschneid3r/xUbuntu_18.10  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1488EB46E192A257 E: The repository 'http://download.opensuse.org/repositories/home:/manuelschneid3r/xUbuntu_18.10  Release' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.


My Null for the T-test is  h0: -tcritical < Tstat < +tcritical  I would like a  confidence level of 95%.  If my empirical result satisfies the null, but not my confidence requirements (the p value was 0.36),  does this mean that the test is inconclusive? Or that the null is not-rejected/rejected?  The t-test I have performed is the 'T-test:unequal variances' on Microsoft Excel  Identical procedure to this   I'm a beginner with modelling, so I thank you for your patience in explaining things


Is it possible to get UNIX time from such date 2011-02-27 02:04:46?

Mktime and other functions give wrong answer for such a date like 2011-02-27 02:04:46;


Without manipulating the actual date and time using the datetime module, is there any way to basically say:  # wait x amount of time  call_function()   Is there any way to replicate that without using datetime? If not, how would I do it using datetime?


Is there a fix for the "Too many open files in system" error on OS X 10.7.1?

I need to get rid of the pesky "Too many open files in system" limit on OS X 10.7.1.   Is there a way?


Proving that for $n \equiv 0 \pmod{2}$, we get ${n \choose 0} < {n \choose 1} <\ldots< {n \choose n/2-1}<{n\choose n/2}$ etc.

How can one prove that for $n \equiv 0$ mod $2$  we have  $${n \choose 0} < {n \choose 1} <\ldots< {n \choose n/2-1}<{n \choose n/2}>{n\choose n/2+1}>\ldots>{n\choose n-1}>{n\choose n}\,?$$  Can I say that for fixed $n$, the binomial coefficients $n \choose k$ increase with $k$ for $k < n/2$? If n is even (like in our case), then the central binomial coefficient $n \choose n/2$ is the largest one.   So $n \choose k+1$ is greater than, equal to, or less than $n \choose k$ according as $n-k$ is greater than, equal to, or less than $k+1$, that is according as $k$ is less than, equal to, or greater than $(n−1)/2$.  Is that correct?


How to I prove the equivalence of $f(S_1 \cup S_2)$ and $f(S_1) \cup f(S_2)$ (Discrete Mathematics)

If $S_1$ and $S_2$ are both subsets of some arbitrary set $A$, then how do I prove that $f(S_1\cup S_2) = f(S_1) \cup f(S_2)$ for ALL cases  I understand that it is true, but I don't know how to prove it.


Looking for MD5 utility that integrates to Windows

Is there any small utility that integrates with the Windows shell and computes md5 of files on demand? I'm too lazy to launch the command line.


Square root of a number squared is equal to the absolute value of that number

Possible Duplicate:          The square root of a number squared is equal to the absolute value of that number. Why is $\sqrt{x^2} = |x|$? Why not just $x$? Please give me a reason and also help me prove it.


Why/How does the determinant of the Hessian matrix, combined with the 2nd derivatives, tell us max., min., saddle points? Reasoning behind it?

In my classes, we are taught the following.  If the determinant of the Hessian matrix at the critical point $\det(D^2f(c)) > 0$ and $f_{xx}(c) > 0$, the function $f$ at c is concave up.  If the determinant of the Hessian matrix at the critical point $\det(D^2f(c)) > 0$ and $f_{xx}(c) < 0$, the function $f$ at c is concave down.  If the determinant of the Hessian matrix at the critical point $\det(D^2f(c)) < 0$, the function $f$ at c is a saddle point.  However, the reasoning behind this is never explained. We are never taught WHY or HOW.  I would like to know why the determinant of the Hessian matrix, combined with the second derivative at the critical point, contains this information about max., min., and saddle points. I would also like to know how this is derived, as I think this would likely go hand-in-hand with why.   Please give clear reasoning behind each step - not just 'this is what it is' without any reasoning.  When researching this topic, I recall reading mentions regarding eigenvectors or eigenvalues, but I honestly cannot remember.   Thank you.


Avoid updating kernel as I need a specific kernel for my processor?

I am going to install Xubuntu 12.04 LTS as it has a non-pae kernel that I need to get it to run on my old PC. Is there any way I can update everything other than the kernel once I get it installed?


Adding large images to posts fails silently

Attempting to add a large (15MB) image to a post fails with no error message.  When I try to drag and drop the image into the "Add a picture" dialog, it just stays uploading forever. In Chrome's network tools, I see that the post to  has been redirected to .  When I try the standard browse to add, the entire window is redirected to .  Shouldn't I see an error message letting me know the image is too big?  For reference, here's . (No idea why it was 15MB. I guess the Awesome Screenshot Chrome extension isn't so awesome.)


In the following instances of possessive, genitive:   1)      It has taken Dan's father's breath away.   Is the possessive grammatically, correctly used?  or should it be:     It has taken Dan's father breath away.   We have 2 possessives here: first, the father of Dan, and next the breath of the father...  2)   In the following instance:     The smoke was terrible for Dan's and everyone else's health.   or, better would be:      The smoke was terrible for Dan and everyone else's health.   Tnx,


connecting multiple led strips to a single DC power supply

I have 12 led strips that each came with a 3 amp/12vDC power supply.  I want to connect all 12 strips to one DC power supply.  How do I calculate the size power supply I need? Do I increase the wattage or the amperage?


Using Console.WriteLine within a Windows Forms application

I have an external DLL whose source code is C#. From the documentation for the DLL, I determined that it writes its debug messages to the console using Console.WriteLine.  I'd like to use this DLL within a WinForms application. However, what I have discovered is that I cannot see the debug messages emitted by the DLL since a WinForms application does not have a console.  is there a way to capture those debug messages, perhaps even to a simple log file? Of course, using ProcessInfo.RedirectStandartOutput will not work as I do not use the DLL as a process.


An arbibrary hight on header + rest of the height on container

I want to achieve the following behavior like in the image    So, I have a header with an arbitrary height and I want the container to fill the rest of the space. I have the following code:
         My header
 Arbitrary height (ex: 123px)

         Container
 Height = rest of the viewport
    Note: I don't want to use .container{ height: calc(100% - 123px) } because the in the future 123px may change, so I don't want to modify in two places.


If you have done well in undergrad (i.e one of the top students of the graduating class; physics and mathematics major with highest honors; with exposure to engineering) and have done a masters for 1-2 years with research experience and publications (i.e assisted professor and PhD students and have coauthored 2-3 papers), do you have a good chance of going to a top 10 physics graduate school?


Which is Greater $31^{11}$ or $17^{14}$  My try:  Consider $$x=11 \ln(31)=11 \ln\left(32\left(1-\frac{1}{32}\right)\right)=55 \ln 2+11\ln\left(1-\frac{1}{32}\right)$$  hence  $$x=55\ln2 -11\left(\frac{1}{32}+\frac{1}{2048}+\cdots \infty\right) \lt 55 \ln 2$$  Now consider $$y=14 \ln (17)=14 \ln\left(16 \left(1+\frac{1}{16}\right)\right)$$  hence  $$y=56 \ln 2+14\ln \left(1+\frac{1}{16}\right) \gt 56 \ln 2$$  Now we have $$55 \ln 2 \lt 56 \ln 2$$  which implies  $$11 \ln(31) \lt 14 \ln (17)$$ $\implies$  $$31^{11} \lt 17^{14}$$  is there any Elementary way to solve this?


how to tackle this partial differentiation problem

show that if $$f(x, y, z)=0$$ then $$\left ( \partial x \over \partial y \right )_{z}\left ( \partial y \over \partial z \right )_{x}\left ( \partial z \over \partial x \right )_{y}=-1$$  I don't know  how   to tackle this problem although I've tried.


In which situations is it OK to omit articles in short sentences?

Recently, in many new online software I often see that developers omit articles in short sentences, especially on action buttons or tooltips.     For instance: "Add new task" (not "Add a new task"), "Create project" (not "Create a project"), but often in the same software I can see "Make a copy". What are situations it can be justified?


Do I need a UK or Ireland transit visa when flying from the US to a Schengen country?

I am travelling to Budapest and therefore have a Schengen Visa. I hold an Indian passport and a valid US visa. I'm travelling from Chicago-Heathrow-Budapest and returning by Budapest-Dublin-Chicago.  Would I need a transit visa for UK/Ireland?  UPDATE  Hoping this will help someone someday.   I was not allowed to board my return flight (BUD-DUB-ORD) because I do not hold an overnight Irish Transit Visa. They said I could have transited happily if the connecting flight was in the same day, but because I would have to originally land at 10 PM and catch the connecting flight next morning at 10 AM, I needed a transit visa. Well, I thought it was BS, but couldn't help comply with the rules. I booked another last minute ticket and flew via Warsaw via LOT.


Updating Items in Arraylist throws ConcurrentModificationException

I am making a game in java with lwjgl and slick. And I have a World that contains a arraylist with all items laying on the ground that it has to update. But when it updates the items a second time it throws a ConcurrentModificationException.  How can I fix this?  This is the full error:Exception in thread "main" java.util.ConcurrentModificationException     at java.util.ArrayList$Itr.checkForComodification(Unknown Source)     at java.util.ArrayList$Itr.next(Unknown Source)     at com.jakibah.infinyvale.World.HandleItems(World.java:43)     at com.jakibah.infinyvale.World.Update(World.java:65)     at com.jakibah.infinyvale.Game.Update(Game.java:29)     at com.jakibah.infinyvale.Canvas.CreateCanvas(Canvas.java:41)     at com.jakibah.infinyvale.Game.main(Game.java:16)  And this is my code:  World:  package com.jakibah.infinyvale;   public class World {  public Tile[][] map; private int TilesWide, TileHeight; public ArrayList<Item> items = new ArrayList<Item>();  public World(int volume) {      this.TilesWide = volume / 2;     this.TileHeight = volume / 2;     map = new Tile[TilesWide][TileHeight];     for (int i = 0; i < map.length; i++) {         for (int j = 0; j < map[i].length; j++) {             map[i][j] = new Tile(TileType.Test, i * 32, j * 32, 32);         }     } }  public World(int[][] newMap) {     this.TilesWide = newMap[0].length;     this.TileHeight = newMap.length;     map = new Tile[TilesWide][TileHeight];     for (int i = 0; i < map.length; i++) {         for (int j = 0; j < map[i].length; j++) {             switch (newMap[j][i]) {             case 0:                 map[i][j] = new Tile(TileType.Test, i * 32, j * 32, 32);                 break;             }          }     } }  public synchronized void HandleItems() {     if (!items.isEmpty()) {         for (Item i : items) {             i.Update();         }     } }  public Tile GetTile(int xplace, int yplace) {      if (xplace < TilesWide && yplace < TileHeight && xplace > -1             && yplace > -1)         return map[xplace][yplace];     else         return null; }  public void Update() {     for (int i = 0; i < map.length; i++) {         for (int j = 0; j < map[i].length; j++) {             Tile t = map[i][j];             t.Update();         }     }     HandleItems(); }   Item:  public class Item { private ItemType type; private Texture tex; private int x, y; private World w; private int texturefactor; private int durability; private int power;  public Item(ItemType type, Texture tex, int x, int y, World w,int texturefactor, int durability, int power) {     this.type = type;     this.tex = tex;     this.x = y;     this.y = y;     this.w = w;     this.texturefactor = texturefactor;     this.durability = durability;     this.power = power;     this.w.getItems().add(this); }  public void Draw() {     Canvas.DrawQuadTex(tex, x, y, texturefactor, texturefactor); }  public void Update() {     Draw();     CheckPickUp(); } public void CheckPickUp(){     if(Canvas.isColliding(Game.p.getX(), Game.p.getY(), Game.p.getX() + 32, Game.p.getY() - 32, x, y));     System.out.println("Colliding");     this.ToBag(); }  public void ToBag() {     Inventory i = null;     i = Game.p.getI();     Game.world.getItems().remove(this);     i.getInventory().add(new BagItem(type, i, tex, texturefactor, durability, power));   }


How get the disk transfer rate, in percetage usage, for cmd/batch?

I need to know when the hdd is a bottleneck, to improve my batch code on Windows 10 I am looking for a command line for cmd/batch similar to this one, but that helps me to know the disk load percentage. (This is not about the disk space).  wmic cpu get loadpercentage  thank you


Did SO used to have fundamentally different rules about what constituted a good question (see example)?

When reviewing whether or not to reopen a question, I came across .  What surprised me is that, IMO, if someone asked that today, they would be all but crucified (endless downvotes, and most likely closed within minutes).    It's not like the post has a few upvotes and downvotes; it has 21 upvotes and 0 downvotes.  So, are all questions equal, but some are more equal than others?  Or were the rules just different in 2010?    I don't really think that it just slipped through the cracks, because there are 0 downvotes...


Unmet Dependencies mongodb-org-server: Depends libcurl3 (>= 7.16.2)

I was trying to install R-base but I'm facing unmet dependencies. I have tried all possible ways to uninstall and install, re-run mongodb services... but nothing worked. The installation shows an error. Uninstallation doesn't work. This is the error: Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  mongodb-org-server : Depends: libcurl3 (>= 7.16.2) but it is not going to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.  I have tried many solutions from Stack Overflow, but nothing works.


Here's my code:  def date_it(month, day, year):     month= ('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'November', 'December')     d=int(day)     y=int(year)     print month[5],d,",",y   OUTPUT: June 17 , 2016 How do I get rid of the space between 17 and , ?


Put already running exe on top of windows

I am working on a Winform application. On button click I need to launch a new 3rd party exe. For this I am using the following code:  private void btnUserMgmt_Click(object sender, EventArgs e) {     if (!IsAlreadyRunning())     {         System.Diagnostics.Process proc = new System.Diagnostics.Process         {             StartInfo = new System.Diagnostics.ProcessStartInfo             {                 FileName = strAppPath + "ReveaLINXUserMgmt/ReveaLINXUserMgmt.exe",                 Arguments = "192.168.0.121\\TESTDBSERVER",                 UseShellExecute = false,                 RedirectStandardOutput = true,                 CreateNoWindow = true,             }         };         proc.Start();     } }    private bool IsAlreadyRunning() {     var processExists = System.Diagnostics.Process.GetProcesses().Any(p => p.ProcessName.Contains("ReveaLINXUserMgmt"));     return processExists; }   Now it is launching fine and running on the top of my main application window.   I need when some one again click btnUserMgmt button. If ReveaLINXUserMgmt.exe is already running and in minimized state, it will come on top of window.  If user closes the main application, child exe will also to be closed


Let $G$ be a group s.t. $|G|=pqr$, where $p,q,r$ are primes that are not necessarily distinct. Show that $G$ is soluable.  Unless there is a more general method to do this, I was going to break it up into cases when all thee primes are different, when two are the same, and when they are all distinct.   For a group to be soluable, then either it's derivied series has to terminate in the trivial subgroup, or there has to be a series such that every factor is abelian. I've been trying to use both definitions for the case when $G$ is three distinct primes but I am stuck an need some new insights.


What is my context and where do I find it?

I asked a similar question earlier but i don't understand what to do, I also have read other solutions like:  I still don't know what to do, please help:  According to what I understand is that my context = null; and I am not sure why, and how to fix it...   I wrote a UniversImageLoader.class to be able to load images over several activities. Now I have initiated it in all my activities, but in my UIL class, I need to pass a context.  public class UniversalImageLoader {      private static final int defaultImage = R.drawable.ic_android;     private Context mContext;      public UniversalImageLoader(Context context) {         mContext = context;     }      public ImageLoaderConfiguration getConfig(){         //File cacheDir = StorageUtils.getCacheDirectory(mContext);         ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(mContext)//<--the error is in this line                 .memoryCacheExtraOptions(480, 800) // default = device screen dimensions                 .diskCacheExtraOptions(480, 800, null)                 .threadPriority(Thread.NORM_PRIORITY - 2) // default                 .tasksProcessingOrder(QueueProcessingType.FIFO) // default                 .denyCacheImageMultipleSizesInMemory()                 .memoryCache(new LruMemoryCache(2 * 1024 * 1024))                 .memoryCacheSize(2 * 1024 * 1024)                 .memoryCacheSizePercentage(13) // default                 .diskCacheSize(50 * 1024 * 1024)                 .diskCacheFileCount(100)                 .diskCacheFileNameGenerator(new HashCodeFileNameGenerator()) // default                 .imageDownloader(new BaseImageDownloader(mContext)) // default                 .defaultDisplayImageOptions(DisplayImageOptions.createSimple()) // default                 .writeDebugLogs()                 .build();          return config;     }   in HomeActivity:[in every Activity I call it like this]  private void initImageLoader(){         UniversalImageLoader universalImageLoader = new UniversalImageLoader(mContext);         ImageLoader.getInstance().init(universalImageLoader.getConfig());     }   and in all those activities I call it in the OnCreate method like this:  initImageLoader();   So I have read up, looked at other solutions but can't find an understandable answer...your guidance will be highly appreciated!


Understanding SQL IN clause with NULL values

Assume the following tables:  CREATE TABLE X (x_name VARCHAR(100)); CREATE TABLE Y (y_name VARCHAR(100)); INSERT INTO X VALUES ('blue'); INSERT INTO X VALUES ('red'); INSERT INTO Y VALUES ('blue');   Resulting in:  +---------+        +---------+ | Table X |        | Table Y | +---------+        +---------+ |  x_name |        |  y_name | +---------+        +---------+ |  'blue' |        |  'blue' | |   'red' |        +---------+ +---------+   The results of the following queries are as expected:   SELECT * FROM X WHERE x_name IN (SELECT y_name FROM Y); will return one row | 'blue' |. SELECT * FROM X WHERE x_name NOT IN (SELECT y_name FROM Y); will return one row | 'red' |.   Let's insert NULL into table Y:  INSERT INTO Y VALUES (NULL);   The first query will return the same result (blue). However, the second query from above will return no rows. Why is this?


I like to store the current datetime and store that in a variable called Entry date. When I do the above, I get the following message:      var tz = TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time");      var EntryDate = TimeZoneInfo.ConvertTimeToUtc(DateTime.Now, tz);    I get the following message:  The conversion could not be completed because the supplied DateTime did not have the Kind property set correctly.  For example, when the Kind property is DateTimeKind.Local, the source time zone must be TimeZoneInfo.Local.  I tried a number of ways to put Kind but was not successful


What is the math font used in most of the Princeton "In a Nutshell" series?

Lately, I have been trying to find which font is used in most of the "In a Nutshell" books in the Princeton press. However, the font used appears not to be on The Latex Font Catalogue nor be a KpFont or Bitstream Charter font. For example:  or:  What font is used in the images above?


Can i join my friend playing rlcraft (Minecraft) from my ps4?

I need to know if I can join my friend playing mods on his computer from my ps4.


Exponentiation in Python - should I prefer ** operator instead of math.pow and math.sqrt?

In my field it's very common to square some numbers, operate them together, and take the square root of the result. This is done in pythagorean theorem, and the RMS calculation, for example.  In numpy, I have done the following:  result = numpy.sqrt(numpy.sum(numpy.pow(some_vector, 2)))   And in pure python something like this would be expected:  result = math.sqrt(math.pow(A, 2) + math.pow(B,2)) # example with two dimensions.   However, I have been using this pure python form, since I find it much more compact, import-independent, and seemingly equivalent:  result = (A**2 + B**2)**0.5   # two dimensions result = (A**2 + B**2 + C**2 + D**2)**0.5   I have heard some people argue that the ** operator is sort of a hack, and that squaring a number by exponentiating it by 0.5 is not so readable. But what I'd like to ask is if:  "Is there any COMPUTATIONAL reason to prefer the former two alternatives over the third one(s)?"  Thanks for reading!


Does this grep's regex `[c]ron` mean the same as `cron`?

From grep's manual   ps -ef | grep ’[c]ron’       If the pattern had been written without the square brackets, it would   have matched not only the ps output line for cron, but also the ps   output line for grep. Note that on some platforms, ps limits the   output to the width of the screen; grep does not have any limit on the   length of a line except the available memory   Doesn't [c]ron mean the same as cron, because [c] means a singleton set of alternative characters?  Why does it not match the ps output line for grep?  Thanks.


How do I see a C/C++ source file after preprocessing in Visual Studio?

Let's say I have a source file with many preprocessor directives. Is it possible to see how it looks after the preprocessor is done with it?


Book where Earth is being divided up into different time periods by aliens

I'm trying to remember the name of this book. I read the description maybe 20 years ago. It was about the Earth being divided up into different time periods by aliens. Some parts of the Earth were in the present day, others were in World War 2, etc. Can someone help me?


Performance of Non Clustered Indexes on Heaps vs Clustered Indexes

compares the performance for individual select/insert/delete/update and range select statements on a table organized as a clustered index vs that on a table organized as a heap with a non clustered index on the same key columns as the CI table.  Generally the clustered index option performed better in the tests as there is only one structure to maintain and because there is no need for bookmark lookups.  One potentially interesting case not covered by the paper would have been a comparison between a non clustered index on a heap vs a non clustered index on a clustered index. In that instance I would have expected the heap might even perform better as once at the NCI leaf level SQL Server has a RID to follow directly rather than needing to traverse the clustered index.   Is anyone aware of similar formal testing that has been carried out in this area and if so what were the results?


When I move files to a DVD window (It says Drag or Copy files  to write them to disk) I can only do it once.  If I try to "Write to Disk"  The window comes up "Please wait until the estimation of the size is completed. All files need to be Analysed to complete this operation."  This continues with back and forth progress bar for many hours. Nothing else  is done.  I tried installing  sudo apt install brasero   As I read the utility is not installed by default, but it says the utility is up to date.  how can I make writing to DVD work?  Thank you.


How to give stdout to different program on same line?

I could do it long way i.e cat hi.txt | grep 'important url' > imurl cat hi.txt | grep -v 'not important url' > imnoturl cat hi.txt | otherprogram1 cat hi.txt | otherprogramN  However, is there anycommand that allows me to do it in one line. Just curiosity not a neccessity. Like: cat hi.txt | someprogram -p1 ' grep "important url" > imurl ' -p2 ' grep -v "not important url" > imnoturl ' -p3 ' other task ' -pn '' Edit: I want to merge this two: cat $fdns_w1 | pigz -dc | fgrep ".$1" | awk -F 'name":"' '{print $2}' | awk -F '","type' '{print $1}' | sort -u cat $fdns_w1 | pigz -dc | fgrep ".$1" | awk -F 'value":"' '{print $2}' | awk -F '"}' '{print $1}' | sort -u