New to Ubuntu - Realtek Ethernet drivers

I have recently dual boot'd my new rig for my data science stuff. So yea...I'm purely new here Ubuntu (Tho. I hear'd Linux/Ubuntu already lol). I'm currently running an Ubuntu 20.04 LTS with a kernel ver. of 5.4.0-42-generic. As of the moment, I'm running with an ethernet cable and ofc problems with regards to installing the ethernet drivers from Realtek. Firstly, I checked the network description which indicates a network unclaimed... $ sudo lshw -C network *-network UNCLAIMED           description: Ethernet controller    product: RTL8125 2.5GbE Controller    vendor: Realtek Semiconductor Co., Ltd.    physical id: 0    bus info: pci@0000:05:00.0    version: 04    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress msix vpd cap_list    configuration: latency=0    resources: ioport:f000(size=256) memory:fc500000-fc50ffff memory:fc510000-fc513fff  As I scoured in previous forums, you can easily download the drivers from this -> . I DID! the steps from the README file only to hit a road block yet again. By running the autorun.sh file from the command line, it just says $ sudo ./autorun.sh Check old driver and unload it. Build the module and install ./autorun.sh: 31: make: not found  I give it a shot find out my ethernet card and it says $ lspci -knn | grep Eth -A3 05:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller [10ec:8125] (rev 04)     Subsystem: ASUSTeK Computer Inc. RTL8125 2.5GbE Controller [1043:87d7]     Kernel modules: r8169 06:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:2484] (rev a1)  I'm literally needing some help or someone who can thoroughly guide me on how to 'install' the ethernet drivers on this one. :C Regards, astro_cgha


As an amateur mathematician and lover of the sciences I have a well working knowledge of classical mechanics, quantum mechanics, general relativity, quantization, and so on...  But recently I've been intrigued in the concept of string theory and have considered reading Polchinski's text book on the matter. As a lover of mathematics first most are there any different branches of mathematics used in proofs in string theory other then the types of mathematics used in the subjects I have listed above?


US doctor working in Tripoli wants me to open online account

A man I recently started talking to over Facebook says he is a doctor from the US working with the UN in Tripoli.  He wants get out of Tripoli because of terrorist attacks on his camp.  He is asking me to open an online bank account for his account manager to send me money, and then I send the money to the camp head office.  Am I being scammed?


Is there a word for "one who is spoken to"?

Is there an English word for "a person who is spoken to"? I guess you could say speakee or talkee or something but I'm looking for a word that's already well established.


Let $f$ be an entire function and $L$ a line in $\mathbb{C}$ such that $f(\mathbb{C})\cap L=\emptyset$. Show that $f$ is constant function.  If $f$ is not constant  then $f(\mathbb{C})$ is dense set in $\mathbb{C}$, but how can I use that line does not intersect the image set?


Let $a$ and $b$ be positive integers. If $b=ak$ for some $k \gt 0$ then $2^b − 1 = (2^a)^k − 1 = (2^a − 1)m$ for some $m$.

I came across a homework question asking if this is true or false. After plugging in some numbers, this turned out to be true. May I know a proof or explanation for this? I sort of know this is related to congruence and GCD, but unsure of how to start.


Why does logistic regression produce well-calibrated models?

I understand that one of the reason logistic regression is frequently used for predicting click-through-rates on the web is that it produces well-calibrated models.  Is there a good mathematical explanation for this?


Why isn't a straightforward 1/5/15 minute moving average used in Linux load calculation?

Until recently I thought the load average (as shown for example in top) was a moving average on the n last values of the number of process in state "runnable" or "running". And n would have been defined by the "length" of the moving average: since the algorithm to compute load average seems to trigger every 5 sec, n would have been 12 for the 1min load average, 12x5 for the 5 min load average and 12x15 for the 15 min load average.  But then I read this article: . The article is quite old but the same algorithm is implemented today in the Linux kernel. The load average is not a moving average but an algorithm for which I don't know a name. Anyway I made a comparison between the Linux kernel algorithm and a moving average for an imaginary periodic load:   .  There is a huge difference.  Finally my questions are:   Why this implementation have been choosen compared to a true moving average, that has a real meaning to anyone ? Why everybody speaks about "1min load average" since much more than the last minute is taken into account by the algorithm. (mathematically, all the measure since the boot; in practice, taking into account the round-off error -- still a lot of measures)


Can I use a 1-year visa and a tourist visa back-to-back in Spain?

I'm a Canadian citizen and I have a Youth Mobility Visa in Spain that lasts 1 year. After it expires, is it possible for me to re-enter on a tourist for another 3 months?  For example, if my 1-year visa ends on October 14th, will I:    automatically get 3 more months? need to re-enter to get 3 more months? not be able to get the tourist visa at all?


Writing a before delete trigger to delete only based on count of attribute

So I have a table T with some attributes say A and B. A condition on the table is that every value of B must have atleast 'n' rows in the table (with different values of A).  I want to ensure that if a record is deleted from the table T, it can only happen if the atleast 'n' condition holds for the remaining records. That is, if there are exactly 5 rows that have the attribute B with value = 1, then a row with B=1 cannot be deleted.  I'm wondering how I can write a trigger in SQL to handle this, or if a trigger is even the best way of doing this. Any suggestions?


One word - someone so scared that he can't move

I am not able to find an appropriate word to fill in for "scared".  He was so scared, he couldn't move. He turned to stone. He was too shocked. He almost turned to stone and could not move.  What would be a single word that has more intensity than scared or shocked. A word that can convey the figurative meaning of "he turned to stone".  [The following edits are the text of a well-formed and well-considered question () posed by  2017-8-2, later closed as a duplicate of this question. This question had previously been closed due to lack of research. The answers to Geiselmann's question have been merged with the answers to this question.] I am searching for a nice, possibly picturesque and idiomatic way of expressing in English what Germans call Schockstarre - being paralyzed by fear.  in Schockstarre verfallen  The word is used, first, to discribe the state some animals fall into when under threat, for example a beetle may have such a condition - not moving, apparently dead, so that a predator would hopefully turn away disinterested. Second, the word is used to picturesquely desribe a similar state in humans; usually ironically. I tried to find adequate expressions in English but what I found so far seems too normal, not pointed enough to me:  to be paralyzed from shock to be in a state of shock  These expressions seem to be mere descriptions of an actual state of shock, and I feel they lack the expressive power of German in Schockstarre verfallen (which evoces the picture of a motionless beetle or other funny animal). Any ideas? If you need a context: imagine, for example, a newspaper article describing a dangerous international situation, and the White House is unable to do anything meaningful due to inner confusion (I make this up, nothing real is intended here). Or take German car makers who seem to be paralyzed by daily new revelations of their fraudful schemes. Anyway, people who should actually do something, but do conspicuously nothing, and you describe this with irony.


Using R with ArcGIS for Desktop (without using GME)?

I am trying to learn R generally and making statistics for maps. I found some useful tricks for making maps with it but it is not the best you can do. My everyday GIS program is ArcGIS.  How I can use R in ArcGIS?  A tool I use is the GME plugin. Is this the only way?  I tried to use R in QGIS but a plugin I found never worked.


Can Muggles publicly establish the existence of a magical community?

In the Harry Potter universe, wizards and witches have managed to keep Muggles unaware of their existence, across the planet and over many centuries. Up to the timeframe that the novels take place in (the 1990s), I can see how this can be achieved through a combination of discretion and magic, with discretion being the preferred method on occasion (e.g., you don't need magic to slip into Platform 9 3/4 unnoticed, you just need to check that nobody is looking).   Our current world of 2016, however, its a very different place. The UK is (in)famously heavily camera-monitored (). Even more poignantly, a very large (and growing) segment of the population carries an internet-enabled HD camera with them at all times and are willing to use it at a moment's notice (, but it is comedy in part because a more realistic version could happen). It looks like, the moment something magical happens in public, a video of it would be on Youtube/Facebook/Twitter and within minutes.   How does the Ministry of Magic deal with this development? Do they need to create a dedicated corps to monitor social media services and alter records as necessary?


I have watched a few David videos and have noticed he has this pet rabbit. It follows him around and hops when he hops. I was wondering if it's possible to tame a rabbit.


I used a mysql database to create a user's registration form and in my sign up code, I did not specify the encryption type for password. How do I create a login form in php which requires password?


How to find all values for $\alpha$ and $\beta$ such that $\int _0^{\infty }f\left(x\right)$ converge

$f(x) = \begin{cases} x^{\alpha }\left(1-cos\left(1-x\right)\right)^{\beta } & \text{if $\;\;\;0<x<1$} \\ \frac{1}{x^{\alpha }+x^{\beta }} & \text{if $\;\;\;1\ge x$} \end{cases}$  I split into two integrals:  $\int _0^1x^{\alpha }\left(1-cos\left(1-x\right)\right)^{\beta }dx\:+\:\int _1^{\infty }\left(\frac{1}{x^{\alpha }+x^{\beta }}\right)dx$  I want to use the comparison test. but I find it hard to choose $g(x)$ that will give me an answer for $\alpha$ and $\beta$


Any Way to Remotely Control (or at Least View) an iPad without Jailbreaking?

There must be thousands of people in the same situation as me, so I find it hard to believe there isn't a solution.  But I've looked all over and have come up dry.  My elderly Dad got an iPad and is having trouble with it.  He's no dummy, but iOS is new to him and he's not good at describing his problem and what he's seeing to me, 1100 miles away.  I'm sure I could help him if I could just see what he sees.  I had installed LogMeIn on his laptop, and could remotely control and view his screen when he had problems.  I know iOS is different and has different levels of sandboxing and other protection from Windows.  But is there any way to remotely view a WiFi-connected iPad, without jailbreaking?  If not, this seems like a great opportunity for an app developer, or maybe Apple if things are too locked down for a 3rd party app.


Python 3.8: Iterate over 1st and 2nd element, then 2nd and 3rd and so on

I want to compare certain numbers I have in a list with values from another list by creating a range. Like this: r = np.arange(0, 20, 2)  Now, r is an array that looks like this: array([ 0,  2,  4,  6,  8, 10, 12, 14, 16, 18])  Now, I would like to use a for loop starting with the first two elements of r, and create a range, such that for the first iteration the 1st and 2nd elements are considered, then for the second iteration, the 2nd and 3rd elements are considered. So it looks like this for each iteration: range(0,2) range(2,4) range(4,6) range(6,8)  and so on. Is there a function to loop through in this way? I don't want to iterate over non-overlapping chunks, i.e. range(0,2) range(4,6) # This is not what I want range(6,8)  and so on.


Translate code from external encrypted file to protect the code

I am currently working in a programm that has the abillity for implementors to save Vb code in a specific form of the programm , and then the programm includes the code in an auto generated class of the core programm. Is there anyway in VB.NET in a sub() to place some type of command  like the following ? Sub() Read and Decrypt file from c:\xxxx\xxxx.txt  (the file will contain my code) End sub so that the program then puts the code in execution from a somehow encrypted file ... Now , it does something like this : Namespace ESDynamicallyGeneratedCode  Public Class Autogenerated_7268126381276  Inherits Ent.Framework.Platform.CustomCommandsTemplate.ExprEvaluatorImpl   {My Code}  End Class  End Namespace


How does a metric of the form $\mathrm{d}z \mathrm{d}\bar z$ work, if $z$ and $\bar z$ are not independent?

My question is motivated by 2D CFT where one works in "complex coordinates". The question is the following: Suppose I am in 2D flat Euclidean space, i.e.  $$\mathrm{d}s^2 = \mathrm{d}x^2 + \mathrm{d}y^2$$  One of the crucial things here is that $x$ and $y$ are independent. Now it well known that the plane can also be described by one complex number. The point here is that it is ONE complex number, so once I write down:  $$z = x+iy$$  I have everything to describe the complex plane. And yet in every book, they then define  $$\bar z = x-iy$$  so the complex conjugate and write down the metric:  $$\mathrm{d}s^2 = \mathrm{d}z \mathrm{d}\bar z$$  Of course, the norm in the complex plane is given by $z\bar z$ but what I don't understand is that the complex conjugate is not an independent variable, so how does the above metric make sense. Of course, often in the books, they at some point mention that they complexify and essentially consider $\mathbb{C}^2$ in which case $z$ and $\bar z$ are to be considered as independent, then the metric makes more sense. But if you don't complexify, how am I supposed to understand the said metric?  Edit: It seems that the standard answer is that you consider the complexified $\mathbb{C}^2$, but that wasn't my question: If I don't want to go to $\mathbb{C}^2$, and just consider $\mathbb{R}^2$ as $\mathbb{C}$, what would the metric be?


Any English terms for ‘to change the part of speech (of a word) without applying modification’?

Is there any appropriate English terminology for changing the part of speech (of a word) without applying any modification?   This is a concept including verbing (where the verb verb means "to use a word that is not conventionally used as a verb, typically a noun, as a verb").   Korean has a term  for it, but I'd like to know the English one.


Which is better in terms of grammar and why, I wonder?      Once upon a time lived King and Queen...     Once upon a time there lived King and Queen...


Does the mass of an object change as it moves away from the earth?

The mass of a helium nucleus is less than the mass of two isolated protons and two isolated neutrons.  When the component hadrons are assembled, this mass is lost as energy ($E=mc^2$).  This makes it (at least sort of) seem like mass is a kind of potential energy.  Matter and antimatter can annihilate each other, releasing energy ($E=mc^2$).  This also makes it (at least sort of) seem like mass is a kind of potential energy.  If I have a mass at approximately sea-level on Earth, will flying it away from Earth increase its mass?  (If so, is this related to relativistic mass?)  EDIT:  The original question doesn't really ask what I mean to ask.  Suppose that, after the mass has been flown into space, it is stopped relative to Earth.  (I think that would require a geosynchronous orbit.)  Would its mass be different than it was before it left Earth?


Is there a minimal graph in $\mathbb{R}^3$ which is not area-minimizing?

Let $\Omega\subset\mathbb{R}^2$ be an open subset such that $\partial\Omega$ is a closed, simple curve.   I'm trying to find an example of an $u:\overline{\Omega}\to\mathbb{R}$ such that $\Sigma:=\text{graph}(u)$ is a minimal surface and, yet, there exists another minimal surface $\Sigma'$ with $\partial\Sigma'=\partial\Sigma$ and $\text{Area}(\Sigma')<\text{Area}(\Sigma)$.  Does such an example exist?


Let $a$, $b$, $c$, $d$ and $e$ be positive numbers. Prove that:  $$\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{c+d}+\frac{d}{d+e}+\frac{e}{e+a}\geq\frac{a+b+c+d+e}{a+b+c+d+e-3\sqrt[5]{abcde}}$$  Easy to show that $$\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{c+a}\geq\frac{a+b+c}{a+b+c-\sqrt[3]{abc}}$$ is true  and for even $n$ and positives $a_i$ the following inequality is true.  $$\frac{a_1}{a_1+a_2}+\frac{a_2}{a_2+a_3}+...+\frac{a_n}{a_n+a_1}\geq\frac{a_1+a_2+...+a_n}{a_1+a_2+...+a_n-(n-2)\sqrt[n]{a_1a_2...a_n}}$$


I'm sure I have the recipe for the Samum Bomb (to destroy monster nests). But after using two of my own crafted bombs, I see 0/2 in my inventory.  If I try to recreate such bombs with the matching ingredients, I get the hint: "You already have this item". That's not really true .-) Actually I have 0 of 2 of this bombs and can not destroy a third nest.  How can I replenish my stock of Samum Bombs?


What freely available software is equipped for editing PDF Bookmarks?

I know of PDFMod, which I rather like except it has one flaw, I can't seem to be able to add bookmarks before pre-existing bookmarks (see the attached image if this is unclear).   I've looked at this question:  -   That question does not deal specifically with bookmark editing, neither does it specify which software is freely available and which isn't.  I should add that I'm incompetent when it comes to installing software so any software that's not available in the Software Centre requires you to detail exactly how I'm meant to install it. Plus, I would specifically like a software that can handle large (like >80 MB) PDF files without lagging like crazy or closing down.


What would the properties of a particle be that would allow light to orbit it?  Light travels fast. Really fast. Almost to the point where we consider that it's instantaneous, and moves only in a straight line.  We know that's not true though. Light can be influenced in such a way so as to cause it to change course. "Bend" if you will.  Black holes influence light strongly enough as to cause the light to be pulled in without escaping. (at least, as far as we know. right?)  This gives me the fundamental basis for thinking that it would be possible to influence light enough to allow it to orbit a particle. I'm curious if anyone has an idea of what properties a particle like this would have, how it could be described, and whether or not it could exist in our physical reality.


Prove that $\lim_{n\to\infty}a_n\le \lim_{n\to\infty}b_n$

Theorem  Let $\{a_n\}$ and $\{b_n\}$ be convergent real sequences. Assume that there exists a $N\in\mathbb{N}$ so  $a_n\le b_n$ (eq. 1)  for all $n\ge N$. Then  $\lim_{n\to\infty}a_n\le \lim_{n\to\infty}b_n$.  My attempt at proving  Let $a=\lim_{n\to\infty}a_n$ and $b=\lim_{n\to\infty}b_n$. $a$ and $b$ are real numbers because the limit of a sequence of real numbers is a real number (which is a corollary in my textbook). For proof by contradiction, assume  $b<a$.  Let $\epsilon=\frac{a-b}{2}$. Then we can find $N_a,N_b\in\mathbb{N}$ so  $|a-a_n|\le\frac{\epsilon}{2}$ when $n\ge N_a$, (eq. 2)  $|b-b_n|\le\frac{\epsilon}{2}$ when $n\ge N_b$. (eq. 3)  In a textbook I found that I should do the following:  Choose a $n$ so $n\ge\max(N,N_a,N_b$), then eqs. (1-3) are satisfied. Then  $a-\epsilon\le a_n+\frac{\epsilon}{2}-\epsilon$  How do I get that last thing? Is it necessary to do a proof by contradiction or can one do a direct proof?


Allow php sessions to carry over to subdomains

I use php sessions (not cookies, except for session id cookie) for all user data, and when a user goes to their profile user.mydomain.com they are immediately "logged out" untill then remove the subdomain.  Is there a way to accept sessions from all domains as long as its *.mydomain.com


Using remoteWebDriver, can I change the time on the executing system?

I'm trying to functional test some code that is dependent on reading the client date, and I want to validate that it does so correctly. Locally, I can change my system date using Java and run the test using Selenium, but I want to run my tests with RemoteWebDriver. Is there some way I can change the date on the client system? If not, can I spoof the date somehow?


To my best knowledge Java uses pass by value. but if you look below I passed a list and added a Integer to it.  Desired output : list before [] and after should be [] Resultant output : list before [] and after is [20]  Also,  if I initialize the list inside static function that my desired output is achieved .  Can i know the reason for this phenomenon please   import java.util.ArrayList; import java.util.List;  public class NormalTest {      public static void testMethod(Integer testInt, List<Integer> sampleList) {         testInt *= 2;         System.out.println(" Inside testInt :: " + testInt);         sampleList.add(testInt);     }      public static void main(String[] args) {         Integer testInt = 10;         List<Integer> sampleList = new ArrayList<>();         System.out.println(" Before testInt :: " + testInt);         System.out.println(" Before sampleList :: " + sampleList);         NormalTest.testMethod(testInt, sampleList);         System.out.println(" After testInt :: " + testInt);         System.out.println(" After sampleList :: " + sampleList);     } }


So I messed up my $PATH when trying to put BLAST into my /etc/enviroment. Now I can't log in to Ubuntu (version 20.04), each time I attempt a login it just loads a couple of seconds and then sends me back to the login screen. I have tried launching the terminal using Alt+Ctrl+F3 and ran sudo nano /etc/enviroment to write the following, according to an older an similar  and from : PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:"  Yet this does nothing for me and the problem persists. I did change the $PATH within .profile as well but I managed to remove these changes using vim inside the Terminal. Error messages:


Searching for a book involving blocks of fog

I read a book nearly twenty years ago when I was in Jr high.  What I remember is a man traveling around with a teenage girl, (nothing twisted) in a camper I think, and there were these weird blocks of fog or mist. I believe there may have been a dog also. It was a novel in English. I believe it was written in the 70's or 80's. I remember a part in the book where two blocks of the fog got stuck right where a woman's house was. The man and girls stopped there for the night. I remember the girl didn't talk much. That's about all I can remember. I don't even remember the story behind what caused the fog and I really want to reread the book.


I have a Windows Server 2019 VPS for hosting websites. It has all the latest updates. But somehow there is a (partial) hacking attempt. I first noticed it by the SMS I got for high CPU usage of the Microsoft Register Server (regsvr32.exe). With the help of  and  that the cause was a DLL in the ProgramDAta folder. There I found a zip with the name set.zip. Containing the following 5 files. comhij.dll, let.exe, rn.bat, x.mof and xg.dll. Is seems that the .bat file got executed and was running the script. But it failed somehow, maybe Windows Defender or something else was blocking it causing the high CPU. I know this because the last lines in the .bat causes it to delete itself. And I could not find any of the changes the script wanted to make. I copied the zip to my own PC, and Norton 360 immediately identified the let.exe as Hacktool, the comhij.dll as Trojan Horse and xg.dll as Trojan.Get.MTB. The Server has the Windows Firewall active and at the provider level  there is also a Firewall active. I was able to find out that the set.zip was created by one of the AppPools (hosting a  if that matters) with no FTP access. So my question is how to find out how this happened and how I can prevent it in the future? And how an AppPool can write a file to disk outside it's root directory? On request I could post the entire .bat script.


Why is the Flash always so slow in key moments?

I'll try to ask the question as general as possible and I will give some spoilers with specific examples below. I've only watched the TV series of the Flash, but I will happily accept answers from the comics.  So the question in general: Is there any story reason why the Flash suddenly is so slow in key moments of the episodes? The non-canon answer is pretty easy: Because it would be boring, but maybe there is some kind of story-answer, too!?  Examples:  S01E15:      Barry and Joe are driving in the car as Mark strikes the car with lightning. Barry is fast enough to see the lightning move down and is able to get them out of the car. But he couldn't get up and just knock Mark down.   S01E10:      This is the second episode with the "Captain Cold" who fires the cold gun at Barry while "Heat Wave" fires the heat gun at him. Instead of just taking the guns he lets both of them fire at him so the guns would disable each other. He already undressed a robber and put a policeman beside him, but he can't just simply take the gun?   Thanks for your time.


What is the font used  in this image please?  Best Regards,


Why does the c# compiler emit Activator.CreateInstance when calling new in with a generic type with a new() constraint?

When you have code like the following:   static T GenericConstruct<T>() where T : new() {     return new T(); }   The C# compiler insists on emitting a call to Activator.CreateInstance, which is considerably slower than a native constructor.   I have the following workaround:  public static class ParameterlessConstructor<T>     where T : new() {     public static T Create()     {         return _func();     }      private static Func<T> CreateFunc()     {         return Expression.Lambda<Func<T>>( Expression.New( typeof( T ) ) ).Compile();     }      private static Func<T> _func = CreateFunc(); }  // Example: // Foo foo = ParameterlessConstructor<Foo>.Create();   But it doesn't make sense to me why this workaround should be necessary.


Is there a way in Adobe Creative Suite to "share palettes/swatches" across programs?

I use a mixture of InDesign, Photoshop and Illustrator to produce the vast amount of printed media I design at my current position and I find myself faced with copy/pasting color values from one program to another almost all the time, I have tried to find a quicker way but have been unsuccessful. I use a program called  to copy and store my most used colors, but still, it's not the same as being able to select it from the swatches palette in Adobe CS.  So the main meat of the question is:   Can I share my colors/swatches between InDesign, Photoshop and Illustrator and if so, how?


Let $a, b, c$ be real numbers such that $abc=8$. Prove that: $$\frac{a^2}{\sqrt{(1+a^3)(1+b^3)}} + \frac{b^2}{\sqrt{(1+b^3)(1+c^3)}} + \frac{c^2}{\sqrt{(1+c^3)(1+a^3)}} \geq \frac{4}{3}$$   Possible Solution:     $\sqrt{1+k^3} = \sqrt{(1+k)(1-k+k^2)} \stackrel{AM-GM}{\leq} \frac{k^2-k+1+k+1}{2} = \frac{k^2+2}{2} (*)$ Thus:    $$\begin{equation} \begin{split} \displaystyle \sum_{cyc} \frac{a^2}{\sqrt{(1+a^3)(1+b^3)}} & \geq \frac{4}{3} \\ \stackrel{(*)}{\Rightarrow} \sum_{cyc} \frac{4a^2}{(a^2+2)(b^2+2)} & \geq \frac{4}{3} \\ \Rightarrow 3 \sum_{cyc} a^2(c^2+2) & \geq (a^2+2)(b^2+2)(c^2+2) \\  \Rightarrow \sum_{cyc} 2a^2+ \sum_{cyc} a^2b^2 & \geq 72 \end{split} \end{equation}$$   Which is true by applying AM-GM in both sums separately. Hence proved.    The above solution states that $\displaystyle \sum_{cyc} \frac{4a^2}{(a^2+2)(b^2+2)} \geq \sum_{cyc} \frac{a^2}{\sqrt{(1+a^3)(1+b^3)}}$  So it proves that $\displaystyle \sum_{cyc} \frac{4a^2}{(a^2+2)(b^2+2)} \geq \frac{4}{3}$ instead of $\displaystyle\sum_{cyc} \frac{a^2}{\sqrt{(1+a^3)(1+b^3)}} \geq \frac{4}{3}$  Is that or the solution correct?  Generally if we are being asked to prove that $x \geq y$ and we prove that $z \geq x$, does it suffices to prove that $z \geq y$?


Invalid option name error with shebang "#!/bin/bash -o pipefail" in script

I have a file named test.sh:   #!/bin/bash -o pipefail echo "Running test" git diff HEAD^ HEAD -M --summary | grep delete |  cut --delimiter=' ' -f 5   When I try to run this script as:  ./test.sh   I get:  /bin/bash: line 0: /bin/bash: ./test: invalid option name   I ran cat -v test.sh to check if there are carriage returns or anything, but that doesn't seem to be the case. I can run the script if I just run it as bash test.sh. Grateful for any help, and lmk if I can provide more info!


Installing drivers for my Radeon card 16.04

I would like to install the driver for my Radeon graphics card on Ubuntu 16.04. Is it available? If it is, how do I install it?  I tried lspci -nn | grep and got the following:  VGA 00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics  Controller [8086:0116] (rev 09)  01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Whistler [Radeon HD  6630M/6650M/6750M/7670M/7690M] [1002:6741] (rev ff)


Reference an entire sheet in Google Sheets

Is there a way to reference an entire spreadsheet with a cell reference in Google Sheets?  Say I wanted to find out how many cells in Sheet1 were non empty. In sheet two I'd want to do something like  =COUNTA(Sheet1!<magic reference>)   I've tried some common sense things like just using a colon e.g. Sheet1!:, but that doesn't work.  Alternatively you can do something like Sheet1!A:ZZZ or Sheet1!1:1000 but obviously this misses an "infinite" number of rows or columns.  I haven't been able to find any documentation on the language of cell referencing.


Can't migrate my website from localhost to webhost

I can easily install Drupal 7.37 on my webhosting. But cannot migrate the existing website.  I uploaded all the files. Imported the database. Changed settings.php accordingly. But what I see is only 404 - . The basic link is www.orger.besaba.com. What do I do wrong?


NullPointerException when using abstract class

I've been recently working on rewriting my school assignments from C++ to Java, to which I'm still a beginner. I made this class:  package ThreeDimensionalController;  import ThreeDimensionalShape.*; import java.util.Deque;  public class ThreeDimensionalController {     private Deque<ThreeDimensionalShape> setOf3DShapes;     public void displayVolume() {         for( ThreeDimensionalShape s : setOf3DShapes)  System.out.println(s.volume());     }     public void displayArea() {         for (ThreeDimensionalShape s : setOf3DShapes)  System.out.println(s.area());     }     public void add(ThreeDimensionalShape shape) {         setOf3DShapes.push(shape);     } }   and the problem is with method called "add", it doesn't compile - NullPointerException and I do know why, but can't figure out how to deal with it. The ThreeDimensionalShape class is an abstract class, that is extended by 3 other classes called Cone, Cylinder and Cube. I wanted it to work like this:  threedimensionalcontroller.add(new Cone(...));   How do I fix it, so that it works?  @Edit: The NullPointerException is solved, thank you everyone!


wifi problem ubuntu 18.0.4 in hp ay03tx laptop tried every possible solution

i am using hp ay503tx there is A problem with my wifi , wifi is detecting the networks but not all available neworks . and couldn't connect with them   my network detail is   *-network             description: Wireless interface             product: RTL8723BE PCIe Wireless Network Adapter             vendor: Realtek Semiconductor Co., Ltd.             physical id: 0             bus info: pci@0000:03:00.0             logical name: wlo1             version: 00             serial: 3c:a0:67:76:a9:b5             width: 64 bits             clock: 33MHz             capabilities: bus_master cap_list ethernet physical wireless             configuration: broadcast=yes driver=rtl8723be driverversion=4.10.0-33-generic firmware=N/A ip=192.168.43.165 latency=0 link=yes multicast=yes wireless=IEEE 802.11             resources: irq:17 ioport:3000(size=256) memory:b1100000-b1103fff


I am using tmux on a local laptop to connect to a server via SSH in a pane. On that server, I am running several computations via screen. The issue is that the server's screen key bindings such as C-A C-D to detach from session do not work now, probably because of local tmux. Is there a way to tell local tmux to "ignore" key bindings for that particular pane? EDIT: Following the suggested post in the comments, here is what helped me: C-b C-a C-d the first C-b is a local tmux binding, the next two are the remote screen's bindings.


How to download drivers for Canon Pixma TR4520 Printer?

On Ubuntu 18.04, I tried running these commands:  sudo add-apt-repository ppa:michael-gruz/canon sudo apt-get update sudo apt-get install cnijfilter-tr4500series   No luck. :(


If PDFLaTeX fails to compile with     See the LaTeX manual or LaTeX Companion for explanation. Type  H     for immediate help.   I want to press e to get an instance of Emacs. The cursor should be on the position of the error (if TeX knows it)  I guess I should insert   export TEXEDIT="emacs magic"   to my .bashrc but what should I type instead of magic?


Having error when trying to update bit value to "0" using left shift

I'm trying to change the value of x from 5 to 7 to 6 using these bitwise operators. However, the second time where it says x = (x|(0 << 0)); yields no change and is ignored when I trace it. No errors. Any tips? int main() {     unsigned short x = 5;          x = (x|(1 << 1));     printf("%hd\n", x);     x = (x|(0 << 0));     printf("%d\n", x);   return 0; }


What happens when a foreigner gets a traffic fine in the United States?

What happens when a foreigner gets a speeding ticket / traffic fine in the United States? I've heard that the issuing officer will demand payment on site or will confiscate the drivers license.  That sounds a little too extreme to be true but on the other hand I'm not sure how they would enforce punishment for these infractions on people who can just leave the country.


As AD = Anno Domini/year of our lord and BC = Before Christ, BCE = Before Common Era, CE = Common Era.  What does common era mean?


Using complex exponential to represent waves in EM

Ever since we've been using exponentials to work with electromagnetic waves, I've been confused about the imaginary portion and want to confirm my thinking.  What does the imaginary portion represent? Nothing, right? It's just a side effect of using complex exponentials because they are very easy to deal with algebraically. So, in reality we can completely restructure all the math to be written in terms of cos/sin instead and never let a single imaginary number appear, right?


Let $V$ be a $K$-vector space, $f: V \rightarrow V$ a linear map. Under some condition, show that $v, f(v),...,f^n(v)$ are linearly independent.

Let $V$ be a $K$-vector space,  $f: V \rightarrow V$ a linear map. Let $v \in V$. May a number $n ≥ 0$ exist, so that: $f^n(v) \not= 0$ and $ f^{n+1}(v) = 0$. Show that $v, f(v),...,f^n(v)$ are linearly independent.   What i know:   $f^0 = id, f^1 = f, f^2 = f \circ f, ...$ $v, f(v),...,f^n(v)$ are linearly independent if:  $a_1v + a_2f(v) + \cdots+a_nf^n(v)=0 \implies a_1 = a_2 =\cdots= a_n = 0$ $f$ is linear, hence $f(0) = 0$, $af(n) = f(an)$, $f(v_1 + v_2) = f(v_1)+f(v_2)$   My thoughts on it: the definition of linearly independent, in our case, can be rewritten as  $a_1v + f(a_2v) + f(f(a_3v)) + \cdots+f^n(a_nv)=0 \implies a_1 = a_2 =\cdots= a_n = 0$  Taking the function $f$ on both sides we can also obtain  $a_1f(v) + f(f(a_2v)) + f(f(f(a_3v))) + \cdots+f^{n+1}(a_nv)=0 \implies a_1 = a_2 =\cdots= a_n = 0$   ... I feel that i am on the right track, but i can't take it further from here.  So i have to show this sum only becomes $0$ when all $a_n$ are $0$. I thought about a proof by contradiction, but i wouldn't know where i can lead this to a contradiction.   Thanks for all help


A sequences converges in R^N if and only if each of its coordinates converge in R

I am trying to prove that a sequence converges in R^N if and only if each of its coordinates converges in R. p $\rightarrow$ q Given a sequence x = (x_1,..,x_n) for all l > 0 exist y = (y_1,..,y_n) such that d(x, y) < l, for the standard metric space d(x_j, y_j) <=  d(x, y) < l, so we are done. I am using the standard metric space and ,for now, all I know is the metric definition of convergence and that a convergent sequence is bounded. I am not sure how to do the coverse (if each of its coordinates converges in R then the sequence converges n R^n).


Adding .3 to .-3 in a for loop giving me a number in scientific notation and not 0 in PHP. Why?

I have this PHP code below:   $value = -.9; for ($i = 0; $i <= 6; $i++) {     echo "value = $value , ";     $value += .3; }   Output:  value = -0.9 , value = -0.6 , value = -0.3 , value = -1.11022302463E-16 , value = 0.3 , value = 0.6 , value = 0.9 ,    Why am I getting -1.11022302463E-16 and not 0? And what can I do to correct the problem? Thanks again.


Is it grammatically correct to say “Utilities Operations”?

My department is titled Utilities Operations.  We run the utilities (heating, cooling, power) for a public university.    It seems to me that the correct title should be either Utility Operations or Utilities Operation.


Using GRASS algorithms in Sextante under ArcGIS Desktop?

Sextante for ArcGIS comes with SAGA modules.   I know that I can use GRASS algorithms in Sextante under gvSIG.  But how can I use GRASS algorithms in Sextante under ArcGIS Desktop?   I tried to look for any instructions, but could not find any. Any suggestions?


How do fixed lenses "focus" on things at different distances?

I'm trying to understand depth of field and I'm struggling.  If I'm playing with a 50mm fixed lens, and I alter its focus using the little ring around the lens, what is actually changing in terms of depth of field? I'm trying to understand DoF a bit more. From my understanding, it's a calculation of aperature, focal length, and focal distance. By changing the focus manually, what's changing? Is it the focal length?  Sorry if this is vague. I'm just struggling to wrap my mind around the technical details of what happens when you alter a lens's focus. What variable is changing?


Construct a Lebesgue measurable subset A of $\mathbb{R}$ so that for all reals $a<b$,   $$0<m(A\cap(a,b))<b-a $$ under the usual Lebesgue measure $m$.       And then show that if $m(A\cap(a,b))\leq\frac{b-a}{2}$ for any $a<b\in\mathbb{R}$, then $m(A)=0$.   The answer to the first part is a dublicate, but as far as the second bit I am feeling stumped. Any thoughts?  Thank you for the help.


The breakindent feature is the greatest thing ever, but it's in 7.4.338. The latest version in the Ubuntu repos is just 7.4, I think. I notice , but I can't seem to find one for Ubuntu yet. I'm hopeless with compiling things, otherwise I'd compile it myself.


If $a+b=1$, show that $a^{4b^2} + b^{4a^2} \leq 1$. It's given that $a,b \in \mathbb{R^+}$.  I couldn't get the equality case actually. I couldn't get a rigorous way to get the equality case.          EDIT: New method     For the inequality, WLOG assume $a>b$.     Then $a^{4b^2} + b^{4a^2} \leq a^{4a^2} + b^{4a^2} \leq (a+b)^{4a^2} \leq 1$      Is it correct?  Thanks a lot StackExchangers!!


Regression - How do I know if my residuals are normally distributed?

Performing a regression and need to find out if my residuals are normally distributed.


I typically use 2 Google accounts simultaneously in my browser. So whenever I fire up any Google service like Google Maps or YouTube or Google Search, it uses one of the accounts. The problem is that I don't want that account to be used and no matter how many times I switch the account for these services, they seem to default to same account.  Is there any way to tell Google to use a particular account for all Google services by default?    I am not talking about using Google account to sign in to third party websites. I am talking only about Google's own services.  I am using Chrome if anyone is going to suggest client-side solution.


how to prove: every two numbers gcd can be divided by this two numbers any common divisor

for example, I have two numbers: 36 and 48. their gcd is 12. 12 can be divided by any common divisors of these two numbers: 1, 2, 3, 4, 6, 12. Is there a general proof for this? Thanks!


Problem is this:      Suppose for any element $r$ in a ring $R$ with unity $1$, $r$ or $1-r$ is invertible. Then show that non-invertible elements form an ideal of $R$.   It is crystal clear that $-r$ is non-invertible if $r$ is. So I tried to show the sum of two non-invertible elements is non-invertible, and the product of non-invertible elements with any ring element is non-invertible but I'm stuck.  Any help will be appreciated.


1/2" drywall ceiling support 7lb ceiling-mounted speakers?

I recently purchase some JBL SP8II wall-mount speakers that I would actually like to use in the ceilings. However these speakers don't come with a between-the-studs support of any kind (there is a wall bracket but it's a flimsy plastic that wouldn't add any support for a ceiling mount situation).  Do you think my 1/2" drywall ceilings would support these 7lb speakers without creating sag? The installation instructions are basically to cut out a 8"x10" rectangular hole in the drywall and then put the speakers in that hole, mounting them to the drywall.   Thanks in advance!


I am analyzing an experimental data set. The data consists of a paired vector of treatment type and a binomial outcome:  Treatment    Outcome A            1 B            0 C            0 D            1 A            0 ...   In the outcome column, 1 denotes a success and 0 denotes a failure. I'd like to figure out if the treatment significantly varies the outcome. There are 4 different treatments with each experiment repeated a large number of times (2000 for each treatment).  My question is, can I analyze the binary outcome using ANOVA? Or should I be using a chi-square test to check the binomial data? It seems like chi-square assumes the proportion would be be evenly split, which isn't the case. Another idea would be to summarize the data using the proportion of successes versus failures for each treatment and then to use a proportion test.  I'm curious to hear your recommendations for tests that make sense for these sorts of binomial success/failure experiments.


I'm testing the rule below else where and it's working but on my system it's not (centos 7, Apache/2.4.6) [I changed my domain to domain.com for the post here]  the purpose of the rule is to rewrite  to    note that the wordpress rules work but this one does not  RewriteEngine On RewriteCond %{QUERY_STRING} ^id=([^&]+) [NC] RewriteRule ^story\.php$ /?p=%1 [L,NC,R=302]   my .htaccess file is below (incase there are conflicting rules)  RewriteBase / Redirect 301 /forums http://domainforums.com Options -Indexes RewriteRule ^([a-z]{2}|zh-CN|zh-TW)/forums/(.*)$ /forums/$2 [R=301,L,QSA] RewriteRule ^([a-z]{2}|zh-CN|zh-TW)/(.*)$ http://$1.domain.com/$2     [R=301,L,QSA] RewriteRule ^(server-info|mv-server-status) - [L]  <IfModule mod_rewrite.c> RewriteEngine On RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L] </IfModule>


I'm automating a web application (the Mantis bug tracker) and I'm getting an interesting response header from it, called Refresh:  HTTP/1.x 200 OK ... Refresh: 0;url=my_view_page.php   It seems to be acting the same way that  does, and the meta refresh technique implies that it is an equivalent of a header in HTTP.  Problem is, I can't find any mention of the Refresh header in the  or any other definitive documentation on how it should be parsed and what the browser should do when it encounters it.  What's going on here?


Does the US ban on visitors from the Schengen area/UK also extend to Puerto Rico?

March 12th 2020, US banned immigration from people who has been in the Schengen area for the past 14 days. Does this ban also apply for someone arriving from the Schengen area to Puerto Rico?


Overheard on an elevator today,     I didn't realize it was him.   Corrected by the know-it-all,     He.  "I didn't realize it was he."   The know-it-all then went on a rant about how everybody is a dolt for not knowing that.  I swear I have never heard this before in my life.  Is the know-it-all correct?    If so, why is "I didn't realize it was he," grammatically correct?  What rule makes "him" incorrect here?


Stretch DIV inside a DIV to 100% height?

I want to stretch a DIV-Container inside a div to the height of 100%. The DIV-Container i want to stretch has a image inside via     I also want to center the Image vertically afterwards. I prepared a picture which makes my wishes more clear:    This is my Code right now:

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C++ - multiple inheritance for dynamic casting

I have two classes Foo and Bar. I have a data loader that loads data from file and return them as Foo or Bar.  Currently I have the solution as:   struct Foo {    std::vector<Foo> Filter() {      //do something with data and return new Foo's   }   std::vector<int> data;  }  struct Bar : protected Foo {   std::vector<Bar> Filter() {      //do something with data and return new Bar's   } }  template <typename T> DataLoader<T> {      ....      T & Get() { ... } }   where T is either Foo or Bar.  The problem with this solution is that I cannot dynamically choose to return Foo or Bar. I have to reload data. Ue of virtual method is not working, since Filter has different return types. Also, making inheritance public is not an option, because in that case I could do Foo f = Bar(); which I dont want to enable.  I have come up with a solution using multiple inheritance. However, I am not sure if it is correct or it would produce undefined-behaviour.  I have added private class to DataLoader:  struct FooBarStorage : virtual public Foo, public Bar {}   and changed inheritance in Bar to struct Bar : virtual protected Foo.  Now I can have non-templated DataLoader:  class DataLoader {    template <typename T> T & Get() { ... } }   and specialise Get to return Bar & or Foo &. The advantage is, I can load data only once and decide what to return in runtime. With a previous solution, data were loaded with a given type (Foo or Bar) and I was not able to change the type.   Is this a possible working solution or would it produce undefined-behaviour / other problems / performance impacts?


I have a non-convex function of several parameters, that takes real values. I am looking for a good algorithm to find local minima. I am reasonably confident I can come up with descent starting points. I have some simple boundary conditions (parameters need to be positive)  I cannot have an analytical form of the Jacobian.  I looked into Nelder-Mead, but it is said to perform poorly in high dimensions (I have about 7 parameters for my function - do not know if that qualifies as high dimension), and also I could not find an implementation in python / scipy which has constraints.  Can anyone with optimization experience suggest some good optimizing algorithms to try?


How to assert on pagereference where the endpoint of pagereference is predefined

I have a pagereference for which I want to write a test class but get the error  Expected: System.PageReference[/CustomLoginPage], Actual: System.PageReference[/CustomLoginPage]. What am I doing wrong:  Class      /**  * An apex page controller that exposes the site login functionality  */ global with sharing class CommunitiesLoginController {      global CommunitiesLoginController () {}      // Code we will invoke on page load.     global PageReference forwardToAuthPage() {         String startUrl = System.currentPageReference().getParameters().get('startURL');         String displayType = System.currentPageReference().getParameters().get('display');         return Network.forwardToAuthPage(startUrl, displayType);     }     // Code we will invoke on page load.     global PageReference forwardToCustomAuthPage() {         return new PageReference('/CustomLoginPage');     } }   Testclass      /**  * An apex page controller that exposes the site login functionality  */ @IsTest global with sharing class CommunitiesLoginControllerTest {     @IsTest(SeeAllData=true)      global static void testCommunitiesLoginController () {         CommunitiesLoginController controller = new CommunitiesLoginController();         System.assertEquals(null, controller.forwardToAuthPage());           PageReference p = new PageReference ('/CustomLoginPage');         System.assertEquals( p, controller.forwardToCustomAuthPage());        }  }


I noticed in the PHB, page 20, under Speed for Dwarves:     Speed. Your base walking speed is 25 feet. Your speed is not reduced by wearing heavy armor.   However, I cannot find anywhere in PHB that mentions that wearing Heavy Armor imposes any speed reduction.  Does anyone know if I've missed something, or if this is actually some inconsistency in the book and Heavy Armor in fact doesn't impose any speed reduction?


Android phone issue with internet connection via WLAN shared by virtual wifi from my laptop

I try to share my internet connection from my laptop (win7) via virtual wifi to my android phone (Samsung Gio). In an elevated cmd I enter  netsh wlan set hostednetwork mode=allow ssid=VWiFi key=xxx keyUsage=persistent netsh wlan start hostednetwork   The android phone connects to VWifi, but the internet connection is hardly usable on the phone while the internet connection on my laptop is very good at the same time (some Mbps)  What works: I can start WhatsApp, type and receive text messages, so I guess there's no general problem, i.e. config can't be completely wrong - but when I try to send pics or audio or try to receive pics or audio messages then I see from the network monitor on my laptop that the connection doesn't even try to send or receive anything (0 kbps up/down).  What sometimes works: connection to some websites with acceptable speed - but sometimes I don't get a single byte. Also this is not reproducible - the same website sometimes shows up, sometimes android tells my the site was not available.  What never worked so far: connecting to Google Play Store. It always tells me to check my connection and try again.  What I tried so far: I read on problems with IPv6, but no matter if I enable or disable IPv6 in the settings of the virtual Wifi, it doesn't help.  I also read about problems related to static/dynamic IPs, my netsh interface ip show config tells my that dchp isn't enabled on my virtual Wifi connection. If I try to enable it by netsh interface ip set address "myWificonnection" dhcp the android phone won't even connect anymore to the virtual Wifi at all. So there may be a solution here if android would connect with dhcp enabled.  I also read about problems with MAC filters, but this is no router, there's no MAC filter in the virtual Wifi.  When I directly connect to a real WLAN router, everything is fine and working. I have the problems only when trying to get into the internet via the virtual Wifi.  Any ideas what may be configured wrong? Either on laptop or on android? Thanks.


Alternate moves, first one to roll a 6 wins: what's the probability of winning?

Question: Players A and B play a sequence of independent games. Player A starts and throws a fair die and wins on a "six". If she fails then player B throws the same die and wins on a "six" or fails otherwise. If she fails then player A gets the die and throws again, and so on. The first player to throw a "six" wins. Find the probability that player A wins.  Here is what I have done:  A wins right away: $\dfrac{1}{6}$  A fails B wins: $\dfrac{5}{6}\times \dfrac{1}{6}$  A fails B fails A wins: $\dfrac{5}{6}\times \dfrac{5}{6}\times \dfrac{1}{6}$  Unlike another similar question which the player B can win on "five" and "six" after player A fails on the first throw, in this case, the games do not seem to have an endpoint. How should I calculate the probability that player A wins then?


How can I use Einstein's field equations to find the metric tensor?

I have watched and read a lot on the topic of General Relativity and the geometry behind it. I am confident that I can derive an approximation of the the stress-energy-momentum tensor with just the metric tensor, but if I was given the stress-energy-momentum tensor I'm not sure how I would go back to find the metric. How can I use  to find the metric tensor? Would I have to expand all of the notation? Or is there some equation I can plug into my computer to get it? Or is there some other way?


How do I get Derkeethus out of the cave?

How can I get Derkeethus out of the cave? I've tried pushing him and attacking him. I don't know what else to do.  He won't go out either exit.  Any ideas?


We need a hard rate limit on suggested edits, to limit the damage someone can do with blasting the review queue with minor edit suggestions.  Case in point:  peppered the site with a whopping 133 tag-only edit suggestions in 2 hours and 15 minutes. That's one edit every minute on average, but towards the end he was entering a new suggestion every 20 seconds. He only stopped because a  drew enough rejections to have him banned from entering more.  If there was a limit to the number of suggested edits you can enter in a time period we could have stopped this guy earlier. No <2k user needs to edit hundreds of tags across that many questions in 2 hours time.  Considerations   There are cases where a retag drive or tag burninate justifies editing a larger number of posts, but I'd be fine if such tasks were limited to people with 2k+ reputation. A retag or burninate job requires a minimal engagement with the community to know when they are justified anyway. The suggested edit review process, by itself, was clearly not enough to stop this barrage. It cannot be seen as a rate limiting measure, at least not as a sufficiently efficient one.  The vast majority of the edits made in the above example were too minor, leaving spelling, grammar and formatting mistakes in the post untouched. The user was going too fast to pay attention to such details anyway. Yet this user has 98 approved edit suggestions, but all but 6 or 7 I'd have rejected as too minor, so the review process itself is broken.   What should be limited   The number of review votes reviewers have is already limited; I burned through 20 reviews in short order just reviewing the suggestions from just this one user. Certainly the number of unreviewed suggestions should be limited to let reviewers catch up with a user like this. I'd say having 20 outstanding suggested edits pending review is plenty. Suggested edits should be made with some consideration; we don't want minor edits, so if you are suggesting more than 20 in an hour (that's 1 every 3 minutes) you are not improving posts anymore, you are gaming the system to gain reputation.


Is it possible to distinguish between the soft copy and the hard copy of a pdf?

I have a document with a significant difference between its hard-copy and soft-copy.  Something like some text-boxes which should be printed bold and big in the hard copy but should be hidden (or as unobtrusive as possible) in the soft-copy version.  Is it possible in latex to incorporate materials in a pdf which are printed but not displayed?


Downloading historical OpenStreetMap data

Where can I download historical data from OpenStreetMap? I’m I am interested in downloading an OSM .pbf file of a particular city in previous years (say, from 2008 and 2010).


Is there a way to transfer thousand of small files faster on Windows 7?

I noticed that if I transfer a few large files between two hard drives, it's pretty speedy, at around at least 30 MB per second, but if I transfer thousands of files less than 5 KB, it is pretty damn too slow.. around 1 to 2 MB per second.   Is there a way to speed up the copy/paste process with thousands of small files on Windows 7?


While running kmeans clustering in java the absolute difference between the data points 0.33 and 0.99 is displayed as 0.659999999 instead of 0.66.  Why is that?  Both the variables holding the data are of type double and I am using the Math.abs() function.   I saw such a problem only for 0.99. When subtracting using other values, the results were fine.  Thanks for any help


libLAS georeference las file and update header

I am just starting to use libLAS and I had a small issue.  I have next code to generate a las file with georeferenced points:  std::ofstream ofs; liblas::Header header; liblas::SpatialReference srs; srs.SetFromUserInput("EPSG:4326"); header.SetSRS(srs); header.SetPointRecordsCount(1); ofs.open("H:\\temp\\test2.las", std::ios::out | std::ios::binary); liblas::Writer writer(ofs, header);  liblas::Point point(&header); point.SetCoordinates(1.0, 2.0, 3.0); writer.WritePoint(point);  point.SetCoordinates(5, 5, 5); writer.WritePoint(point);  point.SetCoordinates(-1, -1, -1); writer.WritePoint(point);  header.SetPointRecordsCount(3);  writer.SetHeader(header);  writer.WriteHeader(); ofs.Close();   When I run lasinfo over this file I get: It says that I have 3 points, but my spatial reference is none.    Same code above, but if I comment this line:  //writer.SetHeader(header);   I can see the spatial reference, but the number of points is 1.    Am I doing something wrong?


Adding a "next" Button to displayform.aspx

Is there a way of adding a button in the Dispform.aspx or the editform.aspx that will take you to the next item in the list?


At what reputation does a user gain 100% maximum privileges?

While users unlock all possible privileges at 20,000 reputation, their privileges are still "enhanced" as their reputation increases. For instance,   An  is granted per 1000 reputation. An  is granted per 2000 reputation.   Are there any other "enhanced" privileges out there that I am missing? It would be great if someone provided an exhaustive list of incremental privileges, as it's difficult to know for sure without sifting through the entire FAQ/privileges page.  At what point does a user gain 100% access to all possible privileges on the site (i.e. the maximum # of delete votes, flags, etc.)?


Through all the five seasons of Game of Thrones we had never seen a White Walker talking.  Does this mean they can't talk human language (e.g. they have their own language) or we will never see them talking (i.e. they can't talk at all)?


Where do I put the code snippets I found here or somewhere else on the web?

Many posts here or somewhere else contain code, but they do not say where to put it.  Example:  I have found this post:  I'm a newbie with PHP. Where exactly should I place the code from the answer?


How to recover Ubuntu Password if I can log in automatically, but forgot my password

I am a macOS user and installed Ubuntu and dual boot using reFind. I can automatically log into my Ubuntu account but I can’t do actions that require administrative authentication because I forgot my password. Is there a way to reset the password through terminal without actually knowing it? If not, some other posts said to reboot and press shift, Followed by some other steps. but this command won’t work for me. What would be the command if I am using reFind to boot Ubuntu? Thank you


How can I use $HOME or ~/ in my log paths of launchd plist to run as LaunchAgent

My plist has below keys:  <key>StandardOutPath</key> <string>$HOME/launchd.stdout.log</string> <key>StandardErrorPath</key> <string>$HOME/launchd.stderr.log</string>   But it doesn't identify  $HOME. What I want is to load this plist in different user accounts as I cant hardcode my user name.  How can I achieve this ultimate aim?


How can I export my model along with its shaders?

I created an eye with a lot of nodes in eevee but the problem is, there is no way to export the nodes with the model (I didn't import any texture I created them with nodes). What should I do? As you can see the materials are all gone and there is no node neither and it created another material using the same name.  Q: How I can export my model along with procedurally created shaders?


Juan Dela Cruz is a former member of this District formerly assigned at ABCD. Said employee was transferred to ZXC.  Does capital Said infront of the sentence correct? it seems to me it' wrong


Why doesn't "ipconfig /flushdns" completely wipe your DNS?

I've consistently had a problem where "ipconfig /flushdns" + restarting computer doesn't get rid of all the DNS records.  Should it completely flush any and all records in DNS? Why doesn't it usually happen like this? Is there some kind of restriction?


A word for not knowing an appropriate word

What is a word to represent a situation in which we feel short of word to be able to express what we want to or what we are feeling .


I am trying to install Ubuntu 13.04 on my 24Gb MSATA SSD. In my laptop, I've also got a 500Gb SATA HDD. I realize that in order for this to work I need to put my /home directory on the 500Gb HDD.   I've tried installing it by creating a ext4 partition on the SSD and a 8Gb swap partition on my HDD. This resulted in an error saying something similar to Cannot install bootloader, please select an other location for the bootloader.   Now before I waste any more time trying to get it to work I'm going to ask a bunch of questions:   Where should I put the swap partition? How big should I make the swap partition? (I've got 12Gb RAM) My 500Gb HDD is currently in Raid mode. Should I change that (to AHCI or IDE)? Where should I put the bootloader if the error message occurs again? How do I make the home directory point to the HDD instead of the SSD? Can I configure Ubuntu to install software/packages on the HDD instead of the SSD?


I have a 16Gb flash drive, was working fine till it just someday stopped working,  when i plug it the drivers are loaded, but i can't see it the "explorer" i went to "Disk managment" but this is what i get:   as u see the flash drive name is (Disque 1) (sorry it in French) and under F:  when i go to cmd and type: Formt F: i get Can not open volume for direct access. i even tried: chkdsk F: /F /X i got the same message  i tried to use the DiskPart utility, here s what i've done:     List disk   Select Disk 1   Clean   i get:   Virtual Disk Service Error.   There is no media in the device.   Does this means the my drive is broken forever? and there can't be a way to fix it?  USBDeview properties:


Community, please show some holiday spirit!

Why does ? And more importantly: why does she not wear them?    Please, show some goddamn holiday spirit! Can we get Community to wear her hats, either randomly or through popular vote?


There are two $n$-components column vectors $u$ and $v$. $I_n$ is the $n\times n$ identity matrix. Find the inverse of $I_n – uv^T$.


If wild shape ends by falling to 0 hp, does the druid lose concentration?

A druid that is wild shaped reverts "when" they drop to 0 hit points.  Does that mean other effects that occur when a creature drops to 0 hit points also occur (though possibly in any order of the druid's choice)?  Specifically, if the druid were concentrating on a spell, would dropping to 0 hp - even momentarily - suffice to cause the druid to lose concentration by being incapacitated? I can't figure out what RAW or RAI is on this one - does anybody have any pointers (e.g. a rule or rule interaction I missed, or some sage advice)?


i've been working on my project to create QGIS plugin for raster analysis purpose.  It will be easier if we use gdal library.  Are we able to use gdal library to develop QGIS plugin?   If so, how do we set up the gdal package inside the qgis2 plugin environment?


Prove that a semigroup satisfying $a^pb^q=ba$ is commutative

Let $(S, \cdot)$ be a semigroup. There are natural numbers $p,q \geq 2$ such that $a^pb^q=ba$ for all $a,b \in S$. Prove that $S$ is commutative.   I wrote   $$\begin{align} a^{p+1}b^{q+1} &=b^{(q+1)p}a^{(p+1)q} \\  &=b^{p}\cdot(b^q)^p \cdot (a^p)^q\cdot a^q \\  &=b^p\cdot a^p \cdot b^q \cdot a^q \\  &= b^p\cdot b \cdot a \cdot a^q \\  &=b^{p+1}a^{q+1}. \end{align}$$  From the given identity I also got $a^{p+1}b^{q+1}=abab$. Using $a^{p+1}b^{q+1}=b^{p+1}a^{q+1}$ I then got $abab=baba$.  Making $a=b$ in the statement gives $a^{p+q}=a^2$. I don't know what to do from there.


Using same variables in a switch statement

I am making a program to switch to different Algorithms. I would love to know if you could reuse variables in a switch statement.  I have tried looking it up and changing to global and final but nothing seems to work  enter code here  switch(nr){  case 1: //For one algorithm Console.Write("Write your base: ") double b = convert.ToInt32(Console.Readline())  break;  case 2: //For the second algorithm but with the same name on the variable  Console.Write("Write your second base: ") double b = convert.ToInt32(Console.Readline())  <<<<< //ERROR on this line break;   }   I did not expect this too happen due to its different cases  struct System.Double  Represents a double-precision floating point number


"And God said......and there was light." What does these equations mean?

Today while I was on the Internet I came across an interesting picture, that caught my eye. It's :     I don't have to explain why this picture seems interesting to someone who knows the meaning and doesn't. So here's my question:   I'm really curious as to what these equations stand for, I'm not an expert in physics, and since this picture has no name given to the equations I can't really search for this online and learn. So that's why I'm turning to you guys. I would be really glad to know the names of these equations, and maybe also the motivation (reason) of the artist to describe it in such a catchy way/meaning of this.


I am fairly new to hands-on electrical engineering (I have taken Physics II and have played with computers and electronics all my life, but am only now truly seeking to learn how to safely handle many different electrical appliances) and am involved in a greenhouse automation project.  The greenhouse has 220V AC power.  I have a number of submersible liquid pumps that draw 12V, 1.8A DC and have 4A fuses.  I've hacked up some old router and cellphone AC/DC adapters that do the trick, but I would like to add a dedicated DC line to the work space for additional motors, pumps, sensors, and other electronics that need DC power.  My question is: if I have an AC/DC adapter that outputs 12V, 16.5A, 203W DC power, would that fry my 4A fuses (as I suspect?)  What if I have 8 or 9 1.8A pumps wired in parallel?  Could I hook and Arduino Mega into any old DC line, or must I downstep it to the current amperage?


How to determine a schema version at runtime

Is there a portable way or best practice to access a version number for a schema at runtime?  Rationale: you have multiple systems (development, QA, etc.) where you push schema changes from one system to the next. Say you're not sure if you already have the latest schema on the QA system, how can you find out the version of the current schema (preferably automated with a script)?  I could imagine having   a convention on using a table comment (COMMENT ON TABLE with Oracle, is that a standard?) to version every table a special table in the schema storing version information   How do you do this? Is there a best practice?


Let $S = [{(-1)^n+ \frac{1}{n}}$] and $n \in \mathbb{N}$   Find the accumulation point of S.  I don't think there are any, but I am not sure. Can anyone shed some light on this?


For PCA, the best axis for the projection of the points is the one who has the minimal or the maximal inertia?

I am learning statistics mainly from a book : Elements de statistique, from three author of the Brussels University. 5th Edition  On the PCA chapter, however, I need to read from other sources, especially to understand how to describe what the axis represents from individual and variable analysis. I then read the whole courses that can be found everywhere over the Internet. And I have a trouble.  My book wrotes :      La droite qui ajuste le mieux le nuage N* des individus est celle autour de laquelle l'inertie de N* est minimale.   (The line that adjusts the best the cloud N* of individuals is the one around which the inertia of N* is minimal).   And the problem is : almost all other sources I can read are searching for the maximal inertia to find the best axes. I can't figure my book could be wrong (on it's 5th edition such a bug would had been found), so what is it trying to explain to me ? And why do I find the contrary elsewhere ?


How to clean/what to do about getting liquid form of compressed air cleaner on computer equipment?

I'm a little worried. I was using some compressed air cleaner (to be specific, Office Depot® Brand Cleaning Duster) to try to blow the dust off some dusty parts of my computer. The instructions are very explicit about not tilting it at an angle because this could cause the gases to be released in liquid form, but the parts I was trying to clean were at kind of an awkward angle, there was really no good way to get the can in at an upright angle, so some of the liquid did get on the stuff I was trying to clean, unfortunately. It evaporated almost immediately, though.  So now, what should I do? I've seen conflicting information online. Wikipedia says that the liquid form of the gases will act as a solvent, causing unwanted damage to surface coatings, so this is troubling to me, but I don't necessarily trust wikipedia as an accurate source. I have seen it said elsewhere that compressed (canned) air will do absolutely zero damage to your computer, even if you get the refrigerant (the stuff that blows out the nozzle when the can is sideways or upside-down) on your CPU/GPU/RAM/Motherboard.  So, what should I do now? I want to clean the peripherals and such that I used it on off now in the best way possible, to prevent or mitigate any further damage that may or may not have been done or will be done by the liquid. What would be the best method to use now? Just, cloth dampened with water? Isopropyl alcohol? Something else?


JS: function in $(document).ready(xx) not working

I want to implement a function into the $(document).ready(xx) block.  It should look like this but doesn't work:  $(document).ready(function () {     function navTo(target) {         if (target === 'into.html') {             window.location.href = 'into.html';         }         else if (target === 'index.html') {             window.location.href = 'index.html';         }     }      window.init = changeColor();      function changeColor() {         document.getElementById("url").style.color = "#000000";     } });   if I do like this, it works:  $(document).ready(function () {      window.init = changeColor();      function changeColor() {         document.getElementById("url").style.color = "#000000";     } });   function navTo(target) {     if (target === 'into.html') {         window.location.href = 'into.html';     }     else if (target === 'index.html') {         window.location.href = 'index.html';     } }   My relevant HTML code:  click


Rational Coordinates with two intersecting lines.

If there are two 2D lines with rational slopes that intersect, must the intersection point have rational co-ordinates?  I'm having a hard time wrapping my head around this and not sure how you prove it?


I'm using a Java program I made, to act as a client for rest platform called Firebase.  I have also an android app to read to coordinates from the Firebase platform, to update markers on google maps.  So my question is, if I have the latitude and longitude of both point A and point B, how can I calculate the coordinates between those both points?  Imagine this case scenario   Point A (left) lat: 39.091868 long: -9.263187  Point B (right) lat: 39.089815 long: -9.261857     How can I calculate, for example, 10 coordinates between those points?


Prob. 9, Sec. 24 in Munkres' TOPOLOGY, 2nd ed: How to achieve this?

Let $A$ be a countable subset of $\mathbb{R}^2$. How to show that $\mathbb{R}^2 - A$ is path-connected?  My effort:   Let $A = \{ a_1, a_2, a_3, \ldots \}$, where $a_n = (\alpha_n, \beta_n) \in \mathbb{R}^2$ for each $n \in \mathbb{N}$.   Let $x_1 = (\xi_1, \eta_1)$ and $x_2 = (\xi_2, \eta_2)$ be any two given points in $\mathbb{R}^2 - A$.   How to find (explicitly) a continuous function  $f \colon [0,1] \to \mathbb{R}^2 - A$ such that $f(0) = x_1$ and $f(1) = x_2$?   Or, how to find (explicitly) a polygonal path (i.e. a path consisting of a finite number of line segments ) from $x_1$ to $x_2$ none of whose edges intersects $A$?


I see the  404 page didn't survive the migration. The current image is the default for beta sites. Is there a better image in the works to replace the somewhat bland '' and ''?


What is the best way to include Matlab graphics?

Which way of exporting Matlab graphics delivers the best result for inclusion in LaTeX? Is it possible to export scalable vector graphics, or even LaTeX graphics?


Representation under which Pauli matrices transform

In Peskin and Schroeder's Quantum Field Theory, there is an identity of Pauli matrices which is connected to the Fierz identity, (equation 3.77) $$(\sigma^{\mu})_{\alpha\beta}(\sigma_\mu)_{\gamma\delta}=2\epsilon_{\alpha\gamma}\epsilon_{\beta\delta}.\tag{3.77}$$ The author explains that      One can understand the identity by noting that the indices $\alpha,\gamma$ transform in the Lorentz representation of $\Psi_{L}$, while $\beta,\delta$ transform in the separate representation of $\Psi_{R}$, and the whole quantity must be a Lorentz invariant.   How can one see $\alpha,\gamma$ and $\beta,\delta$ transform in different representation?


I am biologist and just new to the field of quantum mechanics and trying to understand the subject by reading. It is said that virtual particles are created due to the uncertainty of energy when consider a time, energy conjugate pair. Which leads to violate the energy conservation principle temporarily. But how a huge uncertainty in energy creates virtual particles? How it could violate the energy conservation principle?


Create arrays from randomly placed letters in Java

How can I create an 80-character string array with the letters a, b, and c? Each time, the places of these letters a, b and c need to be arranged randomly. For example abcbabcabcababbc ... abcba  String[] str = new String[80];


Problem regarding Buoyancy forces and Archimedes principle

A thin-walled container of mass $m$ floats vertically at the separation surface of the two liquids of density $ρ_1$ and $ρ_2$  . The whole mass of the container is concentrated in the part of height $h$.  The question is to determine the immersion depth $h'$of the container in the lower liquid if the bottom of the container has a thickness $h$ and an area $S$ and if the container itself is filled with the liquid of density $ρ_1$.    I applied the fundamental principle of the statics on the container  $Balance$ $Sheet$:  The weight of the container ($-mg$)  The buoyancy force applied by the fluid with density $ρ_2$ ($ρ_2gSh$)  The weight of the fluid with density  $ρ_1$  (-$ρ_2gSh'$)  I summed up the forces and set them to zero and find my $h'$  but then  realised that the fluid with density  $ρ_1$  applied also a buoyoncy force on the top of the container , and the fluid with density  $ρ_2$  applied a buoyoncy force on the other fluid.  Where's the problem ?


New to everything web-programming wise.  I'm trying to vertically align the two wrapper divs so that they are in the middle of the page, irrespective of the browser.   The website can be found here:   I've looked up dozens of tutorials on this very question, and cannot get anything to work.  Any ideas?


How to overload __init__ method based on argument type?

Let's say I have a class that has a member called data which is a list.    I want to be able to initialize the class with, for example, a filename (which contains data to initialize the list) or with an actual list.  What's your technique for doing this?  Do you just check the type by looking at __class__?  Is there some trick I might be missing?  I'm used to C++ where overloading by argument type is easy.


How do I create an instance of a parameterized interface

I have this code:  ObjProcessor processor = getProcessor(); MyClass myObj = getObjToProcess();// MyClass extends PersistentObj   and classes:  public class ObjProcessor {    public <OP extends PersistentObj) void process(Class<OP> objClazz, OP object, Modifier<OP> modifier) {      ...    } } public interface Modifier<T> {     void modify(T obj); }   I am stuck. How do I create an instance of the Modifier to be able to invoke:  processor.process(myObj.getClass(), myObj, ???);     After Ron C's comment, I created this Modifier:   Modifier<MyClass> mod = new Modifier<MyClass>() {     @Override     public void modify(MyClass obj) {        // empty     } };   proc.process(myObj.getClass(), myObj, mod); // compilation error!   Eclipse gave this error:  The method process(Class<OP>, OP, Modifier<OP>) in the type ObjProcessor is not applicable for the arguments (Class< capture#1-of ? extends MyClass>, MyClass, Modifier<MyClass>)


I have spent a lot of time writing a project in Microsoft Visual C# 2010 Express. While creating it I used multiple computers and opted to store the files on a external hard drive. While finishing my project, the hard drive crashed. I am using Windows 7.  I now have roughly one tenth of my work remaining when I open the project.   Anybody have any ideas of how I get any of it back?


How do the dimensions of an "infinite" bar of chocolate change?

Here is a GIF image illustrating a supposedly "infinite" supply of white chocolate.     After watching this repeatedly, I can't definitively say why it doesn't add up. It clearly can't be infinite and the sizes of the pieces don't seem to be changed/edited. My guess is that the volume of the spaces between pieces somehow adds up to the final piece's volume.  However, the real question I have is: how have the dimensions of the array of chocolate changed? That is, if you start with a $6\times 4$ grid of chocolate pips, what are the final dimensions of the almost complete grid? I figure that height need not be considered because the cuts are made normal to the table surface.


I have office 2010 installed and the file was working but suddenly when I try to open it It gives me following error      Excel cannot open the file ... because the file format or the file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.   also I tried a program to repair it.  What can I do?


Clarify a step in proving $\forall n\ge 1,$ the sequence $2, 2^2, 2^{2^2}, 2^{2^{2^2}}, \dots$ is eventually constant $\pmod n$.

The  offers a concise proof-by-contradiction that if $n$ is any positive integer, then the sequence $2, 2^2, 2^{2^2}, 2^{2^{2^2}}, \dots$ is eventually constant $\pmod n$. However, I don't fully understand the following step in that proof: Claim: If the sequence $2, 2^2, 2^{2^2}, 2^{2^{2^2}},\dots$ is not eventually constant $\pmod n$, then the sequence of its exponents $1, 2, 2^2, 2^{2^2},\dots$ is not eventually constant $\pmod k$, where $k$ is the eventual period of $2^0,2^1,2^2,2^3,\dots\pmod n$. Equivalently: If $1, 2, 2^2, 2^{2^2},\dots$ is eventually constant $\pmod k,$ then $2, 2^2, 2^{2^2}, 2^{2^{2^2}},\dots$ is eventually constant $\pmod n.$ Equivalently: If $2, 2^2, 2^{2^2}, 2^{2^{2^2}},\dots$ is eventually constant $\pmod k,$ then this same sequence is eventually constant $\pmod n.$ I'm sorry if this is something obvious/elementary, but would someone please explain why this is true when $n\gt 1?$ How exactly does the claim then depend on $k$ being the eventual period of $2^0,2^1,2^2,2^3,\dots\pmod n?$


So right now I'm doing the Discerning The Transmundane, and the Lexicon Receptacle is not there. I've reloaded my game and everything and nothing has worked. What can I do without having to restart my entire game?


Is the placement of the word "only" correct in the sentence below? If not, where should it be?     Berlin is such a big city that we saw only a fraction of it.


How to pass WHERE condition as PDO prepared statement parameter?

I'm trying to make a simple project using PDO. I have a class UserDAO with two SELECT functions:  public function getAll(){  $query="select * from users";  $res = $this->db->query($query);  return $res; }   ...and this one...  public function getAllWhere($where){  $query="select * from users where ?";  $res = $this->db->query($query,array($where));  return $res;  }   When I call the function getAll(), it works fine:  <?php  $ud = new UserDAO();  $result=$ud->getAll();  foreach ($result as $row){    echo '
'.$row['id'].' '.$row['username']; } ?>   But when I try to user the other function...  <?php  $ud = new UserDAO();  $result=$ud->getAllWhere('id>10');  foreach ($result as $row){    echo '
'.$row['id'].' '.$row['username']; } ?>   ...it doesn't work. The error is:  PDOStatement::execute() expects parameter 1 to be array, string given  How can I pass the whole WHERE condition as a parameter? I would also like to make another step forward and to insert the table name ("users") as a parameter too.  Thanks.


Submitting a URL to Google using PHP/cUrl

I've been successfully submitting xml sitemaps to Google using cURL. The URL is   The problem is that XML sitemaps take several days to be processed, and pictures take a lot more time or can never be indexed at all.  When I manually submit a URL at , it is indexed in less than a minute, but the pictures it links to are not.  Is there a way to programmatically submit a single URL AND its images to Google without using a XML sitemap?  EDIT  Here's an example result, after using the manual tool:


Can someone explain the concept of 'Negative Probabilities' in an intuitive manner?

Can someone explain the concept of  in an intuitive manner? I can't seem to understand this concept. I hope someone can explain this concept in an intuitive manner.


Individual community preferences vs. SE network policy: who wins?

In the recent question , the OP asks where the following question would be appropriate:     What would be the best way to approach someone that works for me about bad odor?   CHAOS team member Abby Miller  by suggesting the proposal  — which is in commitment as I'm writing this — because     One of the up voted example questions there is about dealing with an irritating coworker. This question will be perfectly on topic for that site.   In my opinion,  qualifies for the not constructive close reason*, which applies to all sites in the network, and therefore, the question shouldn't be allowed, no matter how much it has to do with workplaces.  I know Abby isn't the only one who disagrees with me about this. I once had a talk with a mod of some beta about the presence of poll/GTKY questions on his site. His position, in short, was that his community had different rules from SO and its members enjoyed such questions. I don't remember which site it was, it might even be graduated now, but I never did end up participating there.  Anecdotal examples are nice and all, but here's the real question: to what extent can individual communities/sites override network policies? To what extend should they be able to do so?  *: not constructive comes with the description "This question is not a good fit to our Q&A format. We expect answers to generally involve facts, references, or specific expertise; this question will likely solicit opinion, debate, arguments, polling, or extended discussion."


Probability that no side of a dice is rolled more than $k$ times

Suppose, we roll a fair die $n$ times. The expected value of how many times each side of the die will appear is $\frac{n}{6}$. The question is, what is the probability that any side of the die will come up more than $k$ times, where $n>k>\frac{n}{6}$? Or you could put it this way: what is the probability that no side will come up more than $k$ times? Clearly these two probabilities add up to 1.


How to model changing services demand during COVID recovery phase?

With vaccinations the demand in certain services is likely to rise. This rise causes a form of non-stationarity in the demand data of these services. My assumptions are that demand has a period on the COVID level, then a period of recovery, and then a stabilisation on a post COVID level. The concept of level shift could help to model the downward trend at COVID onset, assuming a sharp decline. But would that also help during the recovery fase where the new level is not known, and the level is continuously increasing? Would ARIMA be a way to model this data? Could the same ARIMA model work during all three periods? Are there alternative models to handle this kind of non-stationarity?


If I drag a window to the left or right edge of the screen in Windows, Windows will tack it to that edge and resize it to occupy half the screen.  On some Linux desktops, this also works in dual display setups: if I have two screens next to each other, I can arrange up to four windows next to each other in this manner.  On Windows 7, this behavior seems to work only on the outer edges. I can make one window take up the left half of the left screen, but not the right half of the left screen. Is this behavior configurable, and if so, where?


Extended Euclidean Algorithm in $GF(2^8)$?

I'm trying to understand how the S-boxes are produced in the AES algorithm. I know it starts by calculating the multiplicative inverse of each polynomial entry in $GF(2^8)$ using the extended euclidean algorithm. However I am having some trouble understanding how to perform the euclidean algorithm with polynomials in a field. Could someone please explain how to do this with a step by step example?


What is the etiquette on requesting an upvote?

What is the etiquette on asking for upvotes?  i.e. I answered a question, and the person who asked wrote a comment saying my answer was very useful.  I am also the only answer, on the question and yet I don't have a single upvote.    I understand it would be inappropriate to ask for my answer to be picked as the correct answer.  However, I think maybe this person (who is very new), doesn't understand the purpose of upvotes.  Is it appropriate to request an upvote via a comment?


I'm getting the following error message:     System.QueryException: Didn't understand relationship 'AccountContactRelation' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.   Select Email, Id, (Select ContactId, AccountId From AccountContactRelation) From Contact  In AccountContactRelation object there are two lookup fields for Account and for Contact.  Please advise how to avoid such error message?


Recently I started working on a game with the spritekit engine. My question is not about spritekit in specific though, but generally about game engines.   When I write a loop and run it (eg while i < 100000) my cpu usage goes to 100% normally, but when I run the test game there is no changes especially on cpu usage, why? (I know game engines run in a loop that includes logic and graphic commands.)


I am trying to install steam after installing 15.04. When It should be installed the icon shows in my applications, but wont launch when i click on it. I entered      steam<   in the terminal, and got this...     Setting up Steam content in /home/brandon/.local/share/Steam   /home/brandon/.local/share/Steam/steam.sh: line 475: no match: ssfn*   find: `/home/brandon/.steam/steam': No such file or directory   Running Steam on ubuntu 15.04 64-bit   STEAM_RUNTIME is enabled automatically   Installing breakpad exception handler for appid(steam)/version(0)   libGL error: unable to load driver: nouveau_dri.so   libGL error: driver pointer missing   libGL error: failed to load driver: nouveau   libGL error: unable to load driver: swrast_dri.so   libGL error: failed to load driver: swrast   <   I have tried to Remove it, to Purge it to Install it again. I dont know what is going on. What should I do next?


When was the "do form" introduced in the English language?

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


Is it possible to 'blend' two processors from different computers into one "supercomputer"?

Maybe this is a little bit crazy, and I have the suspicion that it is impossible, however here is the situation. I have an old Xbox which I don't use, and I think it's a shame that all that storage, GPU, and CPU is sitting there accumulating dust. I also have a laptop with whatever specs...  Before jumping to the final question there's a couple things I want to know and I don't know where to get the information:   If I have two identical computers, can I blend the specs of the two to make one computer? In case it is possible two do that, what do I need to learn to blend the hard disks, the GPU, and the CPU?   And the final question, formulated in the simplest way:   Is it possible to use my Xbox to compute with my laptop?


class Boxing2 {      static Integer x;      public static void main(String[] args) {         doStuff(x);     }      static void doStuff(int z) {         int z2 = 5;         System.out.println(z2 + z);     } }   This code compiles fine, but the JVM throws a NullPointerException     Exception in thread "main" java.lang.NullPointerException     at   Boxing2.main(Test.java:4)   I cannot figure out the reason of this.


Setting the editing style on a UITableViewCell

I'm trying to set the editing style property of a UITableViewCell in a Cocoa Touch (iPhone) app.   For an example of what this looks like, check out the Contacts app, where you can see the little green plus sign to the left of some of the cells.   The UITableViewCell inspector in Interface Builder has an editing style drop down, but it doesn't seem to do anything.   Likewise there is a CodeSense completion of an undocumented method called -setEditingStyle: for a UITableViewCell that doesn't seem to work either.   Is this a setting in the table view data source? Has anyone outside of Apple gotten this to work?


Subgroup of matrices with $\det=1$ is isomorphic to commutator group?

Let $G$ be a group of $2 \times 2$ matrices and $N$ be the subgroup of $G$ of matrices with determinant 1. Prove $N=G'$ where $G'$ is commutator subgroup of $G$.  I was able to show $G'$ is subset of $N$ but having difficulty proving converse. My first approach was to break any $n\in N$ into $g_1g_2g_1^{-1}g_2^{-1}$. Then I tried to use normal subgroup property. For $n\in N$, $n=gn_1g^{-1}$ for some $g\in G$ and $n_1\in N$ as $N$ is normal. Now $nn_1^{-1}=gn_1g^{-1}n_1^{-1}$, this shows $nn_1^-1 \in G'$. What should be the next step from here?


Proving combinatorial identity $\sum_{k=0}^{n}(-1)^k \binom{2n-k}k 2^{2n-2k} = 2n+1$ "directly"

This is a homework problem. In the first part of the problem, I managed to use a combinatorial problem to prove the following identity:  $\sum_{k=0}^{n}(-1)^k {2n-k \choose k} 2^{2n-2k} = 2n+1$  But I actually have problem with the second part of the problem which asked me to prove this identity "directly", probably using some form of generating functions/algebra method.  There was a hint given but I got stuck: The hint says to calculate   $\Sigma_{n=0}^\infty\Sigma_{k=0}^{n}(-1)^k {2n-k \choose k} 2^{2n-2k} x^{2n}$  and that it would be useful to consider the fact that $ \Sigma(2n+1)x^{2n}= \frac{d}{dx}\frac{x}{1-x^2} $ and $(1-x)^{-a-1}=\Sigma_{j=0}^\infty {a+j \choose j}x^j$.  I am able to prove both these "possibly useful facts" in the hint, but I don't see how to calculate the suggested double sum or prove the identity. [I would have thought that the combinatorial proof is harder to find!] [You may assume that I am familiar with the formal treatment of power series.]  Any help would be greatly appreciated.


How to create this background with Illustrator?

I was wondering how I can create a background like this using Adobe Illustrator ( ignore the images at the corners, I am only interested at the Orange background ).  Thanks!


Why do some companies offer 401k retirement plans?

Why do companies offer 401k (or other) retirement plans?  Let me elaborate this...  I understand that it could be part of an employee's benefits and that a retirement plan option might increase the company's value and improve employees' retention but are there any other reasons? Does the company have any return on it? Any fiscal/financial facilitation?   Nowadays I can have access to thousands of Mutual Funds and ETFs through regular discounted online brokerage companies (that sometimes are way better than the options offered in 401ks) and a Roth IRA (for the ones who qualify) is generally more advantaged that any 'k' accounts so what's the point?  Also, why a company would prefer matching someone's contributions (and given him or her additional free money) instead of just offering a simple raise?


Problems with USB 2.0 extensions totalling 40+ft

I have a tv about 40+ feet from my pc (multiple rooms and 1 level separate us) I want to use as another monitor. I ran HDMI to the tv which worked fine, but then I tried to run a chain of  multiple 10 ft USB 2.0 M/F from my computer to a USB 2.0 Hub, where I then plugged my keyboard and mouse into the hub. I did this without consulting anyone, and now realize I should have, as I am having problems getting my PC to recognize the devices plugged into the hub. I can plug a single device into the end of the USB chain and that works fine, however I do need two devices on the hub on the end. Signal strength degradation isn't a big deal for me by the way as all I need it for is keyboard/mouse.   I've been reading about active extension USB and powered USB hubs today and think they might be able to solve my problem, but I am not familiar with them. Can anyone offer an idea for a setup so I can use a mouse and keyboard with this tv, all while my PC is 40+ feet away?  There were a couple similar questions I read that did not solve my problem by the way, so I don't think this is a duplicate. Sorry in advance for anything, as I'm new.  please provide a solution for my desired setup


I was playing around with some settings, and now I need to reset GNOME to it's defaults - how do I do that?


Proving Pascal's identity $ \binom{n}{k} + \binom{n}{k+1} = \binom{n+1}{k+1}$

I'm trying to prove Pascal's identity, no luck so far.  I have an answer which seem to include some unexplained shifts that I don't get.  What needs to be proved:  $$ \binom{n}{k} + \binom{n}{k+1} = \binom{n+1}{k+1}$$  This shift is not clear to me: $$\binom{n}{k}+\binom{n}{k+1}=\frac{n!}{k!(n-k)!}+\frac{n!}{(k+1)!(n-k-1)!}$$ $$=\bbox[10pt,border:5px solid blue]{\frac{n!}{k!(n+1-(k+1))!}+\frac{n!(n-k)}{(k+1)!(n+1-(k+1))!}}$$


My pendrive is not working and showing Unknown file System

I have a pendrive when I insert it into one o my port it shows in the My Computer but when I try to explore, it shows please insert a disk into drive H. However my usb drive is well inserted. I tried to format it but it is showing There is no disk in drive H, Insert a disk then try again. Its properties is showing Unknown File System and the used space and free space part showing 0 bytes. I cann't also check for errors in the drive. Its device status:The device is working properly. I also reinstalled the driver but that did not help me. Please suggest some way to recover the issue. Thanks.


Putting text in mysql database using tinymce and php

I am using tinymce editor for writing the text into the database using php. Whenever I am writing anything into the editor using keyboard then the code works absolutely fine. But whenever I copy and paste lorem ipsum text into the tinymce editor then I am getting a syntax error and the database is not getting updated.  following shows the syntax error which of course in not going to be helpful. But still for completing the post I am showing the syntax error related to mysql that I am getting while adding something to the database using tinymce.  You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'Open Sans', Arial, sans-serif; text-align: justify;">It is a long established fa' at line 1