Evaluating the limit of a sequence given by recurrence relation $a_1=\sqrt2$, $a_{n+1}=\sqrt{2+a_n}$. Is my solution correct?

Problem  The sequence $(a_n)_{n=1}^\infty$ is given by recurrence relation:   $a_1=\sqrt2$, $a_{n+1}=\sqrt{2+a_n}$.   Evaluate the limit $\lim_{n\to\infty} a_n$.  Solution   Show that the sequence $(a_n)_{n=1}^\infty$ is monotonic. The statement $$V(n): a_n < a_{n+1}$$ holds for $n = 1$, that is $\sqrt2 < \sqrt{2+\sqrt2}$. Let us assume the statement holds for $n$ and show that $V(n) \implies V(n+1)$. We have that $$a_n < a_{n+1}.$$ Adding 2 to both sides and taking square roots, we have that $$\sqrt{2+a_n} < \sqrt{2+a_{n+1}},$$ that is $a_{n+1} < a_{n+2}$ by definition. Find bounds for $a_n$. The statement $$W(n): 0 < a_n < 2$$ holds for $n=1$, that is $0 < \sqrt2 < 2$. Let us assume the statement holds for $n$ and show that $W(n) \implies W(n+1)$. We have that $$0 < a_n < 2.$$ Adding two and taking square roots, we have that $$0 < \sqrt2 < \sqrt{2+a_n} < \sqrt4 = 2.$$ The limit $\lim_{n\to\infty} a_n$ exists, because $(a_n)_{n=1}^\infty$ is a bounded monotonic sequence. Let $A = \lim_{n\to\infty} a_n$. Therefore the limit $\lim_{n \to\infty} a_{n+1}$ exists as well and $\lim_{n \to\infty} a_{n+1} = A$. (For $(n_k)_{k=1}^\infty = (2,3,4, \dots)$, we have that $(a_{n_k})_{k=1}^\infty$ is a subsequence of $(a_n)_{n=1}^\infty$, from which the statement follows.) We have that $a_{n+1} = f(a_n)$. That means that $A = \lim_{n\to\infty} a_n = \lim_{n \to\infty} {f(a_n)} = f(\lim_{n \to\infty} a_n) = f(A) = \sqrt{2 + A}$. Solving the equation $A = \sqrt{2 + A}$, we get $A = -1 \lor A = 2$. Putting it all together, we get that $A = 2$, because the terms of the sequence are increasing and $a_1 > 0$.   Is my solution correct?


I'm making a small object and it is bit difficult to see what i'm doing.  Usally i just open the N-panel and change it under Display, but can't find that option in the new Blender 3.0 Beta.  I want to make the grid floor smaller.  I want to change the scale to 0.1


Proof of the inclusion-exclusion formula in probability

Let $(\Omega,\mathcal F, P)$ be a probability space and let $A_1,A_2,...,A_n$ be events in $\mathcal F$.  Prove the following inclusion-exclusion formula  $P(\bigcup_{i=1}^nA_i)=\sum_{k=1}^n$ $\sum_{\mathcal J \subset \{1,...,n\}; |\mathcal J|=k} (-1)^{k+1}P(\bigcap_{i \in \mathcal J} A_i)$  I am trying to prove this formula by induction; for $n=2$, let $A, B$ be two events in $\mathcal F$. We can write $A=(A \setminus B) \cup (A\cap B)$, $B=(B \setminus A) \cup (A\cap B)$, since these are disjoint unions, then  $P(A)=P(A \setminus B)+P(A\cap B)$ and $P(B)=P(B \setminus A)+P(A\cap B)$.  Now, $A \cup B$ can be expressed as $A \cup B= (A\setminus B) \cup (A \cap B) \cup (B \setminus A)$, which it's also union of disjoint sets, so  $P(A \cup B)=P(A \setminus B)+P(A\cap B)+P(B \setminus A)=P(A)+P(B)-P(A \cap B)$.  This proves that for $n=2$, the formula is correct.  Now, I want to show that the formula is true for $n \implies$ the formula is satisfied for $n+1$, I got stuck at this point, maybe I could express $P(\cup_{i=1}^{n+1} A_i)=P((\cup_{i=1}^n A_i \setminus A_{n+1}) \cup A_{n+1})=P(\cup_{i=1}^n A_i \setminus A_{n+1})+P(A_{n+1})$ (1)  I can use the inductive hypothesis on the term $P(\cup_{i=1}^n A_i \setminus A_{n+1})$, so $P(\cup_{i=1}^n (A_i \setminus A_{n+1}))=\sum_{k=1}^n$ $\sum_{\mathcal J \subset \{1,...,n\}; |\mathcal J|=k} (-1)^{k+1}P(\bigcap_{i \in \mathcal J} (A_i\setminus A_{n+1}))$  Expression (1) becomes $\sum_{\mathcal J \subset \{1,...,n\}; |\mathcal J|=k} (-1)^{k+1}P(\bigcap_{i \in \mathcal J} (A_i\setminus A_{n+1})) +P(A_{n+1})$  I don't know to to take this expression to the one I want, which is  $\sum_{k=1}^{n+1}$ $\sum_{\mathcal J \subset \{1,...,n+1\}; |\mathcal J|=k} (-1)^{k+1}P(\bigcap_{i \in \mathcal J} A_i)$  I would like to know how to continue this part of the exercise.


The use of definite article with phrases including "of"

Can we sometimes write the "of-phrases" without the definite article? I give few examples. Can we remove the definite articles marked boldly?  However, the identification of relevant covariates needed in modelling can often be challenging.   These allow transparent dealing with confounding bias by enabling the controlling of causal assumptions.   The provided code allows the full production of our findings.


Getting NullPointerException while Overriding equals method of Object class in subclass

/* This is the Car class where the equals method of Object class is overridden to compare contents of 2 objects instead of comparing reference variables of 2 objects */ package langPackage; public class Car  {     private String cName;     private int cModel;      Car (String sName, int cModel)     {         this.cName = cName;         this.cModel = cModel;     }      public boolean equals(Object Obj1)     {              String s1 = cName;             int r1 = cModel;              Car c = (Car) Obj1;              String s2 = c.cName;             int r2 = c.cModel;              if((s1.equals(s2)) && (r1==r2))             {                 return true;             }             else              {                 return false;             }         }     public static void main(String[] args)      {         Car c1 = new Car("Ciaz",2018);         Car c2 = new Car("Celerio",2017);         Car c3 = new Car("Ciaz",2018);         Car c4 = c1;          System.out.println(c1.equals(c2));         System.out.println(c1.equals(c3));         System.out.println(c1.equals(c4));     }  }


lebesgue measure of difference of two sets

Suppose $A,B$ are in $\mathbb R^n$, $A$ lebesgue measurable and $|(A \setminus B)\cup(B\setminus A)| = 0$.  Show $B$ must be lebesgue measurable as well and $|A| = |B|$ (where $|\cdot |$ is the lebesgue outer measure).


Two and a half men features Charlie Sheen as a hedonistic jingle-writer.  He has a beach house in Malibu and spends a lot of money while he is rarely shown working.  So, how much does he really earn and how? Royalties?


I learnt in Merriam-Webster and other reliable sources that advice differs from advise. Advice is a noun while advise is a verb. Same goes with the words device and devise.    However, the word practice does not differ from practise as stated by the Merriam-Webster Dictionary. Is it true? Or the rule is still the same like on the words advice and advise? Here are some examples the Webster Dict. used:       You need to practice what you preach.- It is a verb because it entails that   you need to apply or carry out what you have been preached.        Being a good musician takes a lot of practice- It is used as a noun   because it entails a systematic exercise for proficiency in music.


Just finished my semester in advanced abstract algebra and there was one question that I could not answer.     Let $R$ be commutative and let $(e_1,...,e_n)$ be a base for $R^{(n)}$. Put $f_i=\sum_{j=1}^n a_{ij}e_j$ where $A=(a_{ij})\in M_n(R)$. Show that the $f_i$ form a base for a free submodule $K$ of $R^{(n)}$ if and only if $\det A$ is not a zero-divisor.


Not working this if statement on android (Java)

Im trying to compare the versionName of my android app located in the build.grade with the version that takes from a external database.  My script is this:  version.add(jsonarray_appdata.getJSONObject(i).getString("version"));                         String versionName = BuildConfig.VERSION_NAME;                         String str = version.toString();                         versionName = "[" + versionName + "]";                         if(versionName != str){                             Intent intent2 = new Intent(getApplicationContext(),Update.class);                             startActivity(intent2);                             finish();                         } else {                             Thread myThread = new Thread() {                                 @Override                                 public void run() {                                     try {                                         sleep(3000);                                         Intent intent = new Intent(getApplicationContext(),MainActivity.class);                                         startActivity(intent);                                         finish();                                     } catch (InterruptedException e) {                                         e.printStackTrace();                                     }                                 }                             };                             myThread.start();                         }   The versionName value is "[1.3]" and the str value is "[1.3]". So the values are the same but it never goes to the else {} condition.  I tried removing the [ ] of both, and not working.  There are no blank spaces in the values.  Any idea what is happening?  Thanks!


Where does the expression "long odds" come from?

In English we say an event has "long odds" if it is unlikely to happen, and "short odds" for the opposite.  The question is why?  Best I have been able to get from people:   Long over even (if you are betting then the odds you get from the house are larger then for an even bet) Long as in something being a long way away and harder to hit/achieve/get to.


How does the Split feature of Ooze creatures interact with buffs or debuffs?

Bart the Bard is fighting against three .  Bart casts  to protect himself from their attacks, which all three fail.  Bart then sends a lightning bolt through all three. Unfortunately, Black Puddings have the Split feature:     Split. When a pudding that is Medium or larger is subjected to lightning or slashing damage, it splits into two new puddings if it has at least 10 hit points. Each new pudding has hit points equal to half the original pudding's, rounded down. New puddings are one size smaller than the original pudding.   They split into 6 medium-sized Black Puddings.  Which (if any) of those 6 Black Puddings are affected by Bane?


I've got the following bit of C# code running on .NET Core 2.2 to launch a Java process and wait for its execution:  using (var validator = new Process()) { validator.StartInfo.FileName = "java"; validator.StartInfo.Arguments = finalArguments; validator.StartInfo.UseShellExecute = false; validator.StartInfo.RedirectStandardOutput = true; validator.StartInfo.RedirectStandardError = true;  try {     validator.Start();     validator.WaitForExit(); }   When run on Linux, this code works absolutely fine - Java process runs and exits.  When run on Windows, the Java process will just hang for a long while for some reason and not properly exit:    If I pause the debugger, the debugger pauses on validator.WaitForExit();. If I kill the Java process manually, my application continues as normal.   What could be making the Java process hang and not exit correctly on Windows?  Edit: I'm running my function async so it doesn't hang the application, in case it makes a difference:  Task<OperationOutcome> validateWithJava = Task.Run(() => ValidateWithJava());


Would elements heavier than iron not be extremely rare if only created by supernovae?  I believe all elements above hydrogen are created in the star's corona. Hydrogen fusion is not possible in star's centre as pressure and temperature are relatively low and hydrogen would not gravitate  to that region. The surface of the sun is only 8000 K where the corona is about 15000000 K.


When using custom path style in a tikz graph the quotes label isn't printed

I can put labels onto normal edges fine, but when the edge has a style applied to it, the label is no longer applied.  Any idea what is going on/how to fix this?   \documentclass{standalone} \usepackage{tikz} \usetikzlibrary{graphs,quotes} \begin{document} \tikz[hv path/.style = {to path={-| (\tikztotarget)}}] \graph[grow down sep, branch right = 4em] { A ->["this prints"] B ->{C,D}; A ->[hv path,"this doesn't"] D; };  \end{document}


What is difference between "recognizable" and "decidable" in context of Turing machines?


On the equation $3x^3 + 4y^3 + 5z^3 = 0$

How can I show that the equation $$3x^3 + 4y^3 + 5z^3 = 0$$ has nonzero solutions modulo every integer but not in $\mathbb{Z}$?


Just wanted to know why planetary orbits get to be elliptical? I'm not debating how stable these orbits are (obviously almost completely stable), but why don't planets revolve in the special ellipse known as a circle? Wouldn't the centrifugal/-pedal forces between the planet and Sun make the planet revolve around the Sun in a perfect circle? Is there a 'third force' that attracts planets at a specific point (a hypothetical reasoning for elliptical orbits)? I'm not trying to disprove Kepler over here, but I don't exactly get it.


Bijection between open and closed interval

I am not sure how to approach the following problem:  Show the open interval $(a,b)$ is bijective with the closed interval $[c,d]$.  I was thinking of using $a+u$ where $u$ is a really small number and $b+v$ where $v$ is a really small number to make a new interval $[a+u, b-v]$, which is equivalent to (a,b).


Inviting my friend to my minecraft pc singleplayer world

My friend uses minecraft pocket edition while I use minecraft pc edition. Is it possible to invite my friend to my singleplayer world? and how?


Whats the best way to convert a contractor's rate to an employee's rate


Remove the space between column name in MSACCESS dynamically

I have created a web application which uses Database as MSACCESS, one of the column name in MSACCESS is separated with space something like "Employee Name".  My c# code is failing and not able to read the column name which has space between two words. I cannot change the column name as it was used by many applications.  Can i dynamically add underscore or remove the space in a specific column.  Or can someone suggest the best approach for this.  SELECT      Format([empdate],'mm') AS Month,      Sum([Time]) as MyTime      Format([empdate],'yyyy') as CurrYear  FROM Table  where empName ='" + AND ManagerName='XYZ'  Group by Format([empdate],'mm') ,Format([empdate],'yyyy')    in the query say empdate is emp date and ManagerName is Manager Name - i am getting exception while executing in c#


Chrome 100% CPU usage, again - software_reporter_tool.exe

software_reporter_tool.exe belonging to Chrome running at 100% cpu, fan full speed.  Deleting it doesn't fix anything, because it gets redownloaded again! Disabling "Protect me from bla bla" doesn't make it stop running.  Please anyone have any solutions?


QGIS road style appears blocky, I want it to appear continuous. Is there a style merge function or something similar?

If you look closely and see the main roads, they break down into blocks [][][][].   I was wondering in QGIS how can I have them appear continuous and not blocked up as shown below. This is one file and not multiple ones.


In Inception movie final scene, why does the spinning top never comes to rest?

In Inception movie climax, why does the director cut to black before the spinning top is shown coming to rest?


Is it safe to give credit card first 6 numbers+ last 4 over email?

A company that I had previously had a subscription with and cancelled continues to charge me, so I contact their support team and they say that their system shows me to be cancelled. They have asked me to give the first 6 digits and last 4 of my credit card over email after a long back and forth. Is this safe details of my credit card to send or should I do it phone or perhaps just contact my bank. The company is SCRIBD, a reading service btw.


Time freezes and actors and things can be viewed from different angles. What is this special effect called and how is it made?

The  shows an effect previously seen in movies like “The Matrix”.                                  What is it is called and how is it made?


I cant find the themes folder  so i tried to create one in the home directory but it tells me it already exists


I'm having a strange issue where alpha images appear as completely black. It doesn't seem consistent and i'm not sure why. Anyone got an idea?


Implicitly calling a method in a class from main

I am new to Java and I am trying to solve an exercise given by my professor. He has given this class  public class MioPunto { public int x; public int y; public String toString() {     return ("[" + x + "," + y + "]");   } }   and I am supposed to write another class with a main method. Into the main I have to print the coordinates without explicitly calling the "toString" method. I unconsciously solved it in this way  public class TestMioPunto{ public static void main(String[] args){     MioPunto inizio = new MioPunto();     MioPunto fine = new MioPunto();     inizio.x=10;     inizio.y=10;     fine.x=20;     fine.y=30;     System.out.println("Inizio: " + inizio + "\n" + "Fine: " + fine);   } }   and the output is  I can't understand how Java automatically called the toString method (brackets and commas), can you please explain?


How to compute entropy of networks? (Boltzmann microstates and Shannon entropy)

I also asked in SO  a few days ago, thought it may be also interesting for physics-related answers.  I would like to model a network as a system.  A particular topology (configuration of edges between vertices) is a state-of-order of the system (a micro-state). I am trying to compute the entropy of a specific topology as a measure of the complexity of information embedded in that topological structure.   I don’t have a degree in physics, I would like to have answers that can help in creating a concept of entropy applied to networks (particularly small-world networks), as systems embedding information in their topology.  Below, I share my reasoning and doubts.   I first thought to make an analogy with Shannon entropy applied to strings: Here entropy is a measure of the randomness of a string as a sum of probability to have certain digits happenings.  Similarly, I then thought that entropy may hold for an Erdős–Rényi random network, and the measure could reflect the randomness of an edge between a pair of vertexes.   Does Shannon entropy hold for non-random types of networks?  As a second approach, I thought that according to Boltzmann’s definition, entropy is the multiplicity of equivalent states.    How could equivalent topologies be modelled (or how to can we compute similarity between two networks)?  How to measure how much a state of order of a particular topology is “uncommon”, with respect to all other possible configurations?  Should I attempt to model a topology as a probability over all possible distributions of edges (complete network)?


Feature request / idea: Sometimes a question seems to fall in between two sites.  An example might be  email questions, could be the code or could be the php.ini which often ends up being a system administrator. So my idea is that there could be a check box to show it on another site as well. It would be grayed out on the other site and only visible to people with high reputation points, and they could approve it, and then everyone would be able to see it on the other site as well. Maybe they could add answers, or maybe it would just be visible and people could go to the other site to add the answers. So for example, if the question was posted on Stack Overflow, there could be a 'show on Server Fault' check box. Which Server Fault  moderators / high reputation points users could vote to be shown there as well. These could also maybe be community-wiki so simplify the reputation points question. One downside I can think of is that maybe this might create more confusion about what to put what where worse, and maybe that would outweigh any benefits. Maybe it has been thought of, but I just thought I would share the idea...


Are bounties refunded on deleted questions?

I've researched here on MSE, but I haven't found a definitive answer to whether bounties are refunded on deleted questions. According to , bounties are not refundable. Does this also apply to deleted questions, or does it only apply to non-deleted posts?


For all uncountable set,  Is there an uncountable subset such that its complement is also uncountable?  How can I prove this?


Abort trap: 6 error when working with array in C

I am a beginner to C and am trying to get more familiar with arrays and the concept of manual memory allocation by doing simple exercises. I have been reading all the (many) questions on SO regarding the "Abort trap: 6" error, and though I've learned a lot, they haven't solved my issue.  Similar threads I checked out include:      ...and more, all slightly different than what I'm dealing with.  The problem seems to be that I'm writing to memory I don't have access to, but I thought that by making the array big enough when I declare it, I would avoid this issue. Evidently I was wrong!  The code is supposed to simply create an array that holds 100 ints (in positions 0 to 99), and assign each one the value of its position (i.e. the first item in the array should be the int 0, and the last should be the int 99). When I run this code, I get all the example printf statements as expected – with the correct values in them – but it's followed by a line saying "Abort trap: 6".  Could someone take a look at my code and tell me what I'm doing wrong to cause this error?  #include <stdio.h>   int main(void) {     int obvs[101];      for (int i = 0; i < sizeof(obvs); i++)     {         obvs[i] = i;     }      printf("obvs[9] = %i\n", obvs[9]);     printf("obvs[13] = %i\n", obvs[13]);     printf("obvs[37] = %i\n", obvs[37]);     printf("obvs[74] = %i\n", obvs[74]);     printf("obvs[99] = %i\n", obvs[99]);      return 0; }


Badges earned and privileges unlocked in the profile page shows in a weird manner

Why am I seeing badges earned and privileges unlocked like this in the profile page? I can see this issue in several Stack Exchange sites.        The problems in the above screenshot are:   "You earned a new privilege" should be above the green checkmark in the first box. "Edit community wikis" (or whatever privilege was unlocked) should be beside the green checkmark in the first box and not hidden beside the Track the next one > button in the first box. "Congratulations!" should be above the green checkmark in the second box. The earned badge should be beside the green checkmark and not hidden behind the second box. "Thanks to your efforts" text is missing in both the boxes.   Here is an image showing these problems:        It should look something like this:        I'm using Firefox 40.0.3 on Linux.


How should I check the assumption of linearity to the logit for the continuous independent variables in logistic regression analysis?

I am confused with the assumption of linearity to the logit for continuous predictor variables in logistic regression analysis. Do we need to check for the linear relationship while screening for potential predictors using univariable logistic regression analysis?   In my case, I am using the multiple logistic regression analysis to identify factors associated with nutritional status (dichotomous outcome) among the participants. The continuous variables including age, Charlson comorbidity score, Barthel Index score, hand grip strength, GDS score, BMI etc. My first step is to screen for significant variables using simple logistic regression. Do I need to check for the linearity assumption during simple logistic regression analyses for each continuous variables? Or should I just check for it in the final multiple logistic regression model?  Besides, for my understanding, we need to transform the non-linear continuous variable before enter it into the model. Can I categorize the non-linear continuous variable instead of transformation?


Why this code isn't working? In my mind the next() method should move the cursor for the next item of the list...  List<string> listX = new List<String> {'A','B','C'}; while(listX.iterator().hasNext())     system.debug(listX.iterator().next());   When I try to run it I receive a error message of exceed a governor limit of CPU time. It's happend because the next() method doesn't move the cursor for the next list item. Every time returns "A".


No option for enabling wifi in ubuntu 16.04 after dualbooting it with Windows 10 in hp-Notebook

Its been a long searching for a solution to enable wifi in my hp-Notebook laptop after i dual booted ubuntu along with windows 10 but all in vain.   Now before some of you downvote this question and flag it as dublicate i must tell you that I tried answers , ,  ,  many other links, sources, videos and what not, but nothing worked so far. I have lost hope but still seeking a great answer from an angel and intelligent mind to get me out of this desperate situation.   The funny part is, the same worked in virtual box without any error. Every thing was fine but now its not the same.  If somebody needs any further information regarding anything, please let me know i will provide you all the information you need. I have tried the things in additional driver but that too in vain.  Any kind of help will be greatly appreciated. Thanks in advance.  speedious@speedious:~$ lspci -knn | grep Net -A3; rfkill list 0d:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)     Subsystem: Hewlett-Packard Company BCM43142 802.11b/g/n [103c:804a]     Kernel modules: wl 1: hci0: Bluetooth     Soft blocked: no     Hard blocked: no  speedious@speedious:~$ sudo modprobe wl [sudo] password for speedious:  modprobe: ERROR: could not insert 'wl': Required key not available


show that Cov(X+ Y, X-Y)= Var(X) - Var(Y)

I have up until Cov(X+Y,X-Y) = E[((X-E(X))+(Y-E(Y)))((X-E(X))-(Y+E(Y)))] and now I am stuck and do not know how this turns into Var(X)-Var(Y)


I recently installed the 'dash-to-dock' extension for Gnome on Ubuntu 18.04 as I liked the way it looked as opposed to the default dock. I liked the extension although I wasn't keen on the auto-hide feature as I like to see the dock at all times so I can see what applications I have open and badge icons for messages, etc. I turned off the autohide feature. Although when I did that I got this:  The dock pushed up the window instead of overlaying it as I expected it would and how it appeared when autohide was enabled. I checked in settings but I wasn't able to find anything to change this. I also tried the 'dash-to-pannel' extension but it didn't acheive what I wanted. There didn't seem to be much about this online either. I was wondering if there was a way to achieve this either by using this extension or another one or is it just not possible in Gnome?


Does using an extender actually change the aperture of the lens?

I just bought a Canon 2X extender and I always believed that it would only result in 2 stops' loss of light and not change the aperture.    However, when I tested this extender on a Canon 135mm f/2 lens, the maximum aperture I could set went down to F/4.  So it kind of confused me, because if I step down the aperture to f/5.6, is it actually setting the aperture to f/5.6 or f/2.8 (i.e., 1 stop below f/2)?


Make the Stock Widget display percentage change

Is there a way to make the Stock Widget in iOS's Notification Center to display percentage change instead of price change? Any Cydia tweak?  In the Stocks.app you can switch between those and market cap by pressing the price change tile on the right.


How do you import the new OS X Photos app to Adobe Lightroom?

I recently purchased a new camera to start my photography hobby. I have an SD card that I put into my Macbook Pro, and was able to easily import pictures from it into Lightroom.   This didn't work, however, because the pictures remained on the SD card and upon removing it the photo links were all broken in Lightroom.  I decided to, instead, import them to the new Photos app with the intent to then import them from there to Lightroom, but there seems to be no option to do this and I can't find the pictures from within Lightroom.  The images are visible in the Photos app, however, so they're definitely on the Mac.  I'm new to Lightroom and new to the Macbook, so I'm convinced that this is user error but I don't know what I'm doing wrong. I just want to get the pictures off my SD card, onto the Macbook and editable within Lightroom. How do I do that?  EDIT  I'm using Lightroom CC. I read something once about installing an addon within Lightroom but the option wasn't there because Creative Cloud is apparently slightly different from the older versions?


Gate to allow only one player to pass through

On my server I have a quiz which you need to take before you can go to most of the areas, build etc... However, sometimes people try to cheat by going with friends into there. I want some kind of gate/mechanism which only allows one player to pass through and insert some kind of delay or so after this. Is this possible? For the delay I know how to make it, I only need to know if you can build something where only one person can pass through, not multiple at once.


Azure malicious activity / SSH brute force

Recently, I got e-mail from Microsoft Azure Safeguards Team saying that there was a complaint of malicious activity originating from my deployment (VM).  Description is: "SSH Brute Force".  Now, I wasn't even remotely sure what this means. That someone used my VM for some malicious activity, and brute forced into it, or used it to brute force somewhere else?  I'm pretty sure no one had access to my Ubuntu Azure VM since last password change.  It was said that all this may result in suspension of my deployment. And I can't afford that because this machine is used to deploy a business application.  So my question is - what methods of protection should I look into, in order to prevent incidents as the one described above? What else should I use besides firewall on a Linux VM in cloud(Azure)? For now, the port 22 is closed, until I resolve this issue.  Thanks.


InputStream return NullPointer : java.lang.NullPointerException at org.apache.pdfbox.text.PDFTextStripper.(PDFTextStripper.java:1825)

im trying to index pdf files using pdfbox 2.0.7 source version and lucene 6.6.0. im getting this following errors.  Exception in thread "main" java.lang.ExceptionInInitializerError     at org.apache.pdfbox.examples.lucene.LucenePDFDocument.addContent(LucenePDFDocument.java:361)     at org.apache.pdfbox.examples.lucene.LucenePDFDocument.convertDocument(LucenePDFDocument.java:254)     at org.apache.pdfbox.examples.lucene.LucenePDFDocument.getDocument(LucenePDFDocument.java:326)     at javaapplication18.JavaApplication18.indexDocs(JavaApplication18.java:112)     at javaapplication18.JavaApplication18.indexDocs(JavaApplication18.java:90)     at javaapplication18.JavaApplication18.main(JavaApplication18.java:67) Caused by: java.lang.NullPointerException     at org.apache.pdfbox.text.PDFTextStripper.<clinit>(PDFTextStripper.java:1825)     ... 6 more   and open the PDFTextStripper.java and found this  static     {         String path = "org/apache/pdfbox/resources/text/BidiMirroring.txt";         InputStream input = PDFTextStripper.class.getClassLoader().getResourceAsStream(path);         try         {             parseBidiFile(input);         }         catch (IOException e)         {             LOG.warn("Could not parse BidiMirroring.txt, mirroring char map will be empty: "                     + e.getMessage());         }         finally         {             try             {                 input.close(); // here is PDFTextStripper.java:1825             }             catch (IOException e)             {                 LOG.error("Could not close BidiMirroring.txt ", e);             }         }     }   PDFTextStripper.java:1825 pointing at input.close();  i need help. what i should to do?


I tried blender on my laptop, the top of the window seem to be cut, and i can't see every tool especially taskbar which's supposed to be there. That's not such a big problem but the real problem is that the cursor is copletly off when i try to click on something the cursor actually goes way higher than what i was aiming for.  The white cross is actually where my cursor is supposed to be and you can see the taskbar is missing up there


Getting disk i/o statistics for single process in Linux

I need to monitor the I/O statistics of a process that writes to disk. The purpose is to avoid write rates too high for long periods.  I know there's iostat tool to accomplish this task on a system-wide perspective.  Is there something similar to monitor single process disk usage?


What would be gravity in one spatial dimension?

First of all, I should say that I understand if this is put on hold for being unclear... but I'll try my best to make it as clear as it can get.  For all the time I spent learning Newtonian Gravity (school etc), I've associated it with the fact that the gravitational field "dissipates" with the area it covers based on the distance it is from a given point. This seemed reasonable to me, if we think of gravity as a field generated by a particle. And this seems consonant with the fact that it depends on the inverse of the square of distance:  $$\displaystyle |F|=G \frac{Mm}{||\textbf{x}-\textbf{x}_0||^2}. $$  I don't know if this is a standard interpretation, my first question is therefore:    Is it?   Okay, going on with the reasoning:  We then have that:  $$\displaystyle F=-G \frac{Mm}{||\textbf{x}-\textbf{x}_0||^3}(\textbf{x}-\textbf{x}_0)$$  By following my reasoning, imagining if we were in a two dimensional space (euclidean space, as in Newton's POV), we would get:  $$\displaystyle F=-G \frac{Mm}{||\textbf{x}-\textbf{x}_0||^2}(\textbf{x}-\textbf{x}_0)$$  and, in one spatial dimension:  $$\displaystyle F=-G \frac{Mm}{||\textbf{x}-\textbf{x}_0||}(\textbf{x}-\textbf{x}_0)$$  Therefore, the force of gravity would be "constant". My second question, then, is:    Does this make physical sense?   Now, I don't know Einstein's General Relativity Theory, but I know differential geometry, and I know that gravity is associated to the curvature tensor. So, if we understand gravity this way, then we can simply give a $1$-manifold some metric, and gravity will be the result of this metric. But I don't know if the metric must be given by something specific, or if it can be arbitrary. If it is arbitrary, this creates much more freedom to gravity: It wouldn't be so restricted as to necessarily imply that the "field" should be constant.   Therefore, my last questions are:   What would be gravity according to Einstein's General Relativity Theory in a $1$-manifold? Would it be VERY different from the Newtonian's perception? If not, is there any support for any (or none) of those interpretations to be physically valid?


Let $G = a_0,a_1, \cdots, a_6$ where $a_i\cdot a_j = a_{i+j}$ if $i+j <  7$ and $a_i\cdot a_j = a_{i+j-7}$ if $i+j \ge 7$.   I'm trying to see whether this is a group or not. The problem is I can't see what the identity element or the inverses would be from the definition. I tried to prove closure and associativity:  (a) By definition for any $a_i, a_j \in G$ we have $a_i\cdot a_j = a_{i+j} \in G$ if $i+j <7$ and $a_i\cdot a_j = a_{i+j-7} \in G$ if $i+j \ge 7$.   (b) For any $a_i, a_j, c_k \in G$ we have $$a_i \cdot (a_j \cdot a_k)=\begin{cases}  a_i \cdot a_{j+k} = a_{i+j+k} & \mbox{if } i+j+k < 7 \\    a_i \cdot a_{j+k-7} = a_{i+j+k-14} & \mbox{if } j+k \ge  7 \\ a_i\cdot a_{j+k} = a_{i+j+k-7} & \mbox{if}  ~i+j+k \ge 7, j+k < 7  \end{cases}$$  And similarly we have $$(a_i \cdot a_j) \cdot a_k=\begin{cases}  a_{i+j} \cdot a_{k} = a_{i+j+k} & \mbox{if } i+j+k < 7 \\    a_{i+j-7} \cdot a_{k} = a_{i+j+k-14} & \mbox{if } i+j \ge  7 \\ a_{i+j}\cdot a_{k} = a_{i+j+k-7} & \mbox{if}  ~i+j+k \ge 7,  i+j < 7 \end{cases}$$  Is this correct?


I have Ubuntu 14.04, and I'm trying to install wine:i386 to use PlayOnLinux, following . However, when I run:  sudo echo "foreign-i386 architecture"> /etc/dpkg/dpkg.cfg.d/multiarch  I get this error /etc/dpkg/dpkg.cfg.d/multiarch: Permission denied  Being still new to Ubuntu I don't know how safe it is (or advisable) to manually change permissions to overcome this. What should I do to solve this?  EDIT The main objective of this question is to install Wine, not the syntax itself (although the syntax was the problem), the accepted answer provided a better way of solving this.


I have found one text is going out of the div while visiting some random posts.    I think there is issue with the "word-break" CSS content.  After applying word-break, it seems to be working fine:


Type conversion in expression may affect "CardinalityEstimate" in query plan choice?

I maintain an archive database that stores historical data in partitioned views. The partitioning column is a datetime. Each table under the view stores one month of data.  We constraint the events on each table with a check constraint on the datetime column. This allows the optimizer to limit the tables that are searched for queries that filter on the event datetime column.  The names of the check constraints were generated by SQL Server, so it's hard to know what they do by looking at their name.  I want the constraint names to have the form 'CK_TableName_Partition'.  I can generate a rename script using this query and copying data from from sql_text column. The WHERE clause matches check constraints whose names look like they were generated by SQL Server:  SELECT   checks.name AS check_name,   tabs.name AS table_name,   skemas.name AS schema_name,   cols.name AS column_name,   N' EXECUTE sys.sp_rename   @objname = N''' + skemas.name + N'.' + checks.name + N''',   @newname = N''CK_' + tabs.name + N'_Partition'',   @objtype = ''OBJECT'';' AS sql_text FROM sys.check_constraints AS checks INNER JOIN sys.tables AS tabs ON   tabs.object_id = checks.parent_object_id INNER JOIN sys.schemas AS skemas ON   skemas.schema_id = tabs.schema_id INNER JOIN sys.columns AS cols ON   tabs.object_id = cols.object_id AND   cols.column_id = checks.parent_column_id WHERE checks.name LIKE (   N'CK__' + SUBSTRING(tabs.name, 1, 9) +   N'__' + SUBSTRING(cols.name, 1, 5) +   N'__' + REPLACE(N'xxxxxxxx', N'x', N'[0-9A-F]') COLLATE Latin1_General_BIN2 ) ORDER BY table_name;   The output looks like this:  check_name  table_name  schema_name column_name sql_text CK__tbAcquisi__Acqui__5C4299A5  tbAcquisitions_201301   Archive AcquisitionDT   EXECUTE sys.sp_rename  @objname = N'Archive.CK__tbAcquisi__Acqui__5C4299A5',  @newname = N'CK_tbAcquisitions_201301_Partition',  @objtype = 'OBJECT'; CK__tbAcquisi__Acqui__76026BA8  tbAcquisitions_201302   Archive AcquisitionDT   EXECUTE sys.sp_rename  @objname = N'Archive.CK__tbAcquisi__Acqui__76026BA8',  @newname = N'CK_tbAcquisitions_201302_Partition',  @objtype = 'OBJECT'; CK__tbAcquisi__Acqui__7D6E8346  tbAcquisitions_201303   Archive AcquisitionDT   EXECUTE sys.sp_rename  @objname = N'Archive.CK__tbAcquisi__Acqui__7D6E8346',  @newname = N'CK_tbAcquisitions_201303_Partition',  @objtype = 'OBJECT'; ... CK__tbRequest__Reque__60132A89  tbRequests_201301   Archive RequestDT   EXECUTE sys.sp_rename  @objname = N'Archive.CK__tbRequest__Reque__60132A89',  @newname = N'CK_tbRequests_201301_Partition',  @objtype = 'OBJECT'; CK__tbRequest__Reque__1392CE8F  tbRequests_201302   Archive RequestDT   EXECUTE sys.sp_rename  @objname = N'Archive.CK__tbRequest__Reque__1392CE8F',  @newname = N'CK_tbRequests_201302_Partition',  @objtype = 'OBJECT'; CK__tbRequest__Reque__1AFEE62D  tbRequests_201303   Archive RequestDT   EXECUTE sys.sp_rename  @objname = N'Archive.CK__tbRequest__Reque__1AFEE62D',  @newname = N'CK_tbRequests_201303_Partition',  @objtype = 'OBJECT';   The result of the query seems to be correct and the server executes it quickly.  But the root node of the execution plan has a warning:     Type conversion in expression (CONVERT_IMPLICIT(nvarchar(128),[o].[name],0)) may affect "CardinalityEstimate" in query plan choice   What does that mean in this context? Is such a complex filter confusing the optimizer? Is it something I should be worried about?


How does Westworld handle guest-on-guest violence?

We've seen guests do pretty much whatever they want to hosts, but what happens should things get ugly between paying customers? Could one complain to management? Would the instigator be kicked out/blacklisted/whatever?


How do I get the text to be flush with one side of the cube?

My graphic designer left our organization, and my Photoshop abilities less advanced. I'm having trouble figuring out how to make the letters flush with the sides of the cube.   The .psd file I have does not have a 3D layer, just the sides. I'm sure it's something simple, but it eludes me.


TIFR GS 2015 computer science: $G = \lim_{n\to\infty}(n+1)\int_{0}^{1} x^{n} f(x) dx$

Following expression was asked to be evaluated in TIFR GS 2015 exam,   $$G = \lim_{n\to\infty}(n+1)\int_{0}^{1} x^{n} f(x) dx$$  where $x \in [0, 1]$ and $f(x)$ be any real valued continuous function.  I have tried using Integration by parts technique but I am not able to solve the integral. I would like to know if any other approach should be used for solving this problem.  P.S. : As per answer key, $G = f(1)$.


Windows 10: Can I safely remove WINRE or RECOVERY partitions?

I'm attempting to install Ubuntu Linux alongside Windows 10 in a dual-boot configuration. However, my hard drive comes with four Primary partitions already created, as seen here in gParted:    Thus, I must remove a partition to allow for an extended partition, in which I can place my logical partitions for Linux. I'll shrink the Windows partition to create space.   I created a recovery USB drive using the HP Recovery Media Creation tool desktop app. Does this drive fully replace the functionality of either the WINRE or RECOVERY partitions? If so, can I safely remove either partition without messing up my Windows 10 installation in any way (including boot process), voiding any warranties, or preventing myself from restoring Windows 10 in the future? I know that holding Shift while clicking the Restart button will restart your computer into a special menu where you can change certain settings or boot from removable media (, step 4 in the article). Is this special menu reliant on either the WINRE or RECOVERY partitions? Is the computer in fact booting into one of these partitions to display this menu? What exactly are the purposes of these two partitions?   NOTE: I've read other questions regarding hard drives with four primary partitions already created. They don't resolve my issue, as they don't address the WINRE and RECOVERY partitions on a Windows 10 system specifically.


What does dash "-" at the end of a command mean?

Given the following command:  gzip -dc /cdrom/cdrom0/file.tar.gz | tar xvf –   What does the - at the end of the command mean? Is it some kind of placeholder?


How do I add grunge & rusting texture to a pre-made material? [CYCLE]

I am working on a nature scene where there is a car due to nature it gets rusted and rather by time it gets old. I want to add grunge and rust texture. I had bought materials plugin a while ago, so used the already made plugins from there. The problem is I have no clue where to apply the roughness texture since I am not that experienced.  Firstly, the grunge and rust textures are from megascan ( not sure if this helps).  First the glass material;  When you expand it this is what it looks like   Where do I apply the image texture of grunges which I got fro megascans to , where do I plug it to be exactly?  Second  I also have another metal material which has scratches over it, and it is premade, I would like to add some rust texture as well from megascans.    I can probably post the whole node, but I don't have 10 rep.


Is it possible to "steal" an event handler from one control and give it to another?

I want do something like this:  Button btn1 = new Button(); btn1.Click += new EventHandler(btn1_Click); Button btn2 = new Button(); // Take whatever event got assigned to btn1 and assign it to btn2. btn2.Click += btn1.Click; // The compiler says no...   Where btn1_Click is already defined in the class:  void btn1_Click(object sender, EventArgs e) {     // }   This won't compile, of course ("The event 'System.Windows.Forms.Control.Click' can only appear on the left hand side of += or -="). Is there a way to take the event handler from one control and assign it to another at runtime? If that's not possible, is duplicating the event handler and assigning it to another control at runtime doable?  A couple of points: I have googled the heck out of this one for awhile and found no way of doing it yet. Most of the attempted approaches involve reflection, so if you read my question and think the answer is incredibly obvious, please try to compile the code in Visual Studio first. Or if the answer really is incredibly obvious, please feel free to slap me with it. Thanks, I'm really looking forward to seeing if this is possible.  I know I could just do this:  btn2.Click += new EventHandler(btn1_Click);   That's not what I'm looking for here.  This is also not what I'm looking for:  EventHandler handy = new EventHandler(btn1_Click); Button btn1 = new Button(); btn1.Click += handy; Button btn2 = new Button(); btn2.Click += handy;


Getting started with quantum computing from a computer science perspective

I started this  on quantum computing (Nielsen and Chuang). I have gone through the first chapter but I need to really understand the concepts; what should I do? Should I cover some background topics or move to some other book. By the way, I have done Bachelors in Computer Science; I never studied quantum before but I started this book so I can start research on quantum algorithms.


A proton and antiproton annihilate at rest into pions

I'm having a difficult time with this particular problem. I'm really hoping for some guidance.  A proton and an antiproton annihilate at rest (or in a $p\bar{p}$ atom in an $S$ state) into pions.  (a) Show that a $\pi^0\pi^0$ state cannot be produced by strong interactions.  I know that a way to do this is to show that the interaction is not symmetric under parity, but am not sure how to go about doing that.  (b) Show that the decay into a $\pi^+\pi^-$ final state is possible from a $^3S_1$ state, but not from a $^1S_0$ state. (Here we use the spectroscopic notation $^{2S+1}L_J$.) Consider $C$, $P$, and $CP$, where $C$ is the charge conjugation operator, and $P$ is the parity operator.  I don't even know what "spectroscopic notation" is.


I have this tiny little program made for fun, wanted to see how interfaces work . When I enter " iarba " onto the eatsOrNot function, for the dog object, I get true , when I am supposed to get false. What am I doing wrong in that boolean function ?   package animals;      public interface Actions {    void Sound();  boolean eatsOrNot(String s);  void guessNumberOfLegs(int x );    }    package animals;   public class Dog implements Actions {     public boolean eatsOrNot(String s)  {      if (s=="paine"||s=="morcovi"||s=="iarba") return false;      else return true;   }   public void Sound() {     System.out.println("Dog goes 'woof'"); }  public void guessNumberOfLegs(int x) {     if (x==4)          System.out.println("Right!");     else    System.out.println("Wrong!"); }              }     package animals;  public class Rabbit implements Actions {         public boolean eatsOrNot(String s)      {          if (s=="fier") return false;          else return true;      }       public void Sound() {         System.out.println("Rabbit goes bla");     }      public void guessNumberOfLegs(int x) {         if (x==4)              System.out.println("Right!");         else    System.out.println("Wrong!");     }   }    package animals;  import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Scanner;   public class TestAnimals {      public static void main(String[] args) throws IOException {         // TODO Auto-generated method stub         Scanner in= new Scanner(System.in);         BufferedReader in1=new BufferedReader(new InputStreamReader(System.in));          Dog dog=new Dog();         Rabbit rabbit=new Rabbit();          System.out.println("Rabbit sound:" );          rabbit.Sound();          System.out.println("Dog sound:" );          dog.Sound();           System.out.println("Guess number of a dog's legs:" );            int legs=in.nextInt();            dog.guessNumberOfLegs(legs);            System.out.println("Guess number of a rabbit's legs:" );             legs=in.nextInt();            dog.guessNumberOfLegs(legs);              System.out.println("The dog eats or not : ");                 String str=in1.readLine();                dog.eatsOrNot(str);                System.out.println(dog.eatsOrNot(str));             System.out.println("The rabbit eats or not : ");            String str1=in1.readLine();            rabbit.eatsOrNot(str1);            System.out.println(rabbit.eatsOrNot(str1));             }  }


how to check if one element is hidden with jquery

I want to show and hide one div as below:  $('#Div1').click(function () {             if ($("#Div2").hidden) {                 $("#Div2").show(500);             }             else {                 $("#Div2").hide(1000);             }          });   this code does not work.  and i want to hide div2 with clicking on empty sapce of page how can i do that and where is my code is wrong?


"Paragraph ended before \Gin@iii was complete" while inserting image with \includegraphics

I'm trying to insert a figure into my LaTeX file using the following syntax:  \begin{figure}   \centering   \includegraphics [width=3in]{fig1.png}   \caption{Calculation of shortest path betweenness}   \label{Fig.3:Shortest path betweenness} \end{figure}   It worked for me before but this time I'm getting the following error:   LaTeX Error: \begin{figure} on input line xxx ended by \end{document}   Also, hovering over the red cross symbol indicating error in Eclipse, I see this message    paragraph ended before Gin@iii was completed.   It's obvious that I have the \end{figure} to end my \begin{figure} so I don't understand how I still get that error.  Can someone please tell me what the problem is?  Edit: Add more details for debugging. The problem went away if I remove '[width=3in]'. Here is the detail error:  pdflatex> Runaway argument? pdflatex> width=3in]{fig1.png} \caption {Caption} \label {Fig.1}  pdflatex> ! Paragraph ended before \Gin@iii was complete. pdflatex> <to be read again>  pdflatex>                    \par  pdflatex> l.40  pdflatex>        pdflatex>  pdflatex> Underfull \vbox (badness 10000) has occurred while \output is active pdflatex> (./document.bbl pdflatex>  pdflatex> Package natbib Warning: Empty `thebibliography' environment on input line 3.   Added sample code:  \documentclass[10pt,psfig,letterpaper,twocolumn]{article} \usepackage{geometry} \usepackage{graphics} \usepackage{setspace} \usepackage{natbib} \usepackage{verbatim} \usepackage[scaled=0.9]{helvet} \singlespacing \paperwidth 8.5in \paperheight 11in \oddsidemargin 0in \headsep 1.3cm  \geometry{left=0.75in,top=0.75in,right=0.75in,bottom=1in} \textwidth 7in  \textheight 9.25in \columnsep 0.4in \footskip 0in  \renewcommand{\bibname}{REFERENCE} \pagestyle{empty}  \begin{document} \bibliographystyle{acm}   \title{\fontfamily{phv}\selectfont{\huge{\bfseries{Title here}}}} \author{ {\fontfamily{ptm}\selectfont{\large{\bfseries{author name}}}}\thanks{contact info }}  \maketitle \thispagestyle{empty}  \section*{\fontfamily{phv}\selectfont{\normalsize{\bfseries{Section name}}}}  \begin{figure} \centering \includegraphics[width=3in]{fig1.png} \caption{Caption} \label{Fig.1} \end{figure}  \pagebreak[4] \vspace*{5.52in} \bibliography{ref} \end{document}


How to paste when using tmux on a remote server with putty

If I start tmux on a remote server while using putty I can't paste using right click.


Now I created RD Web Access (RDWA) in windows server 2008 R2 everything is work well.  I need your help, I have a problem    Customer A use user A in PC A ( user created in windows server 2008 r2) login in RDWA ex: . and run programs Customer A go to another pc (PC B) also login by use User A access webpage . and run programs. Now programs in PC A is disconnect and Programs is continue show in PC B. I want if user A login first another user using the same user can’t login or have a notification “ Another user of your computer is currently using this connection.  This user must disconnect before you can log on.”    Important: I already found notification in source of rd web C:\Windows\Web\RDWeb\Pages\en-US\login.aspx.  please focus   bWorkspaceDisconnected = false but it’s not work if I login one user in the same time ??? how make it work for my section   ****I will explain for you. User A: Login in PC A at 9:22 AM and now he's using. Another people use user A login in PC B in 9:25 AM. I want the people login in time 9:25 Am can't login because user A already login ( 9:22 AM) and now he using** People login after exist user login before will not login for useing. That's my hope please help me. Thank you so much**


What does it mean when Google Search Console URL inspection says resources don't load due to "other error"?

I'm currently analysing some landing pages with the URL inspection tool of the Search Console, and most of them look to be not loaded (script and css). The main reason announced by Search Console is: other error (without any more information).  I was thinking the problem might be that the scripts are too complex, but some of them are very simple.


Simple subtraction that I can't figure out.

A bat and a ball cost £1.10 in total. The bat costs £1 more than the ball. How much does the ball cost?  The answer to this question is somehow 5p. How?!! Should it not be 10p?


`sudo apt-get update` lock error on a fresh 12.04 install ( different angle )

My question(s) are related to the sequence of the following actions: i) I performed a fresh installation of 12.04 on a machine ii) After the installation was complete and the media ( optical disk ) were removed ( as per the prompt ), I rebooted the machine and logged in into the brand-new system. iii) I opened a terminal and tried to do an update of APT's cache ( sudo apt-get update ). This results in apt-get reporting an error due to some conflict it detects ( indicated by the /var/lib/apt/lists/lock file being locked by some other application ) This question ( or related questions ) seems to have been asked several times and one ( plausible ) post explains the error as having been caused by some updating software such as Software Center or Synaptic already running.  Is this systematic ( i.e. part of the installation process )?  Is the system trying to run Synaptic after a fresh installation ( ... perhaps as some automated post-installation sequence which runs on initial log-in )?  Did I get the lock error for apt-get update because I was inadvertently interfering with another instance of apt-get or similar which gets started immediately after the first log in of a user after a fresh installation?   In short I would like to understand why this happened, because as outlined above, after the installation and my firs log-in, I did not launch or start any apps. >other< than the terminal (....from previous experience with the Synaptic package I knew that if you intend to use apt-get you must make sure Synaptic is not running..). Note: You only seem to get this when you try to run sudo apt-get from one of the pseudo terminals within the X windowing system. You don't get the lock error if you use one of the virtual terminals ( the character based ones you get by doing 'Ctrl+Alt+F(1-6)'). Exact error messages ( added at request from one of the commenters @Sushantp606 ): E: Could not get lock /var/lib/apt/lists/lock -open ( 11: Resource temporarily unavailable ) E: Unable to lock directory /var/lib/apt/lists/


I have been pulling my hair out with snap permissions issues. The apps that are specifically giving me the most trouble are Spotify (Premium Account) and bcompare (Beyond Compare). I'm runnning Ubuntu 18.04.1 LTS.  The problem is that snap can't seem to access directories that I need it to.  Spotify, I would like it to access the audio files on an external hard drive that is mounted on /media for all users. The problem it gives me a "Could nor read the contents of "FOLDER" Error opening directory "FOLDER":Permission Denied for folders outside of its snap folder or my home directory.  It also won't follow a symlink to the drive. I presume it must be operating as a different user since my user has access to all drives and directories.  bcompare (Beyond Compare) has the same issue. The whole purpose of bcompare is to compare one directory to another to see if you have missing or duplicate files, but now that it's a snap, the only way I can get it to compare directories on external drives is to change the fstabs of the drives to mount inside the bcompare snap folder, and reboot the computer.  This caused tremendous problems since it changes the directory location, which then messes up syncing to Dropbox and Google Drive-which then start deleting files in the cloud since the directory no longer exists and it takes about a month to resync when I revert the fstab back to the original.  Is there a way to give snap access to the external drives, or run snaps as my user, or add snap to my group, or some way to have snaps access directories outside of their snap folder?


I was trying to move (ctrl + X) from Ubuntu Desktop to a memory card. Moved upto 8G files but unfortunately the card reader disturbed. Got error and when I re insert the card reader I got another error. Inserted card reader in windows machine and I could see only 500MB data. I do not find the data in Ubuntu desktop as well. How to find those image files. Please help me.


Is totally disconnected space, Hausdorff?

Recall a space is totally disconnected if the only connected subsets are singletons (one-point subsets). Is a totally disconnected space,  Hausdorff?     I think it is true since if $a $ and $b $ are two distinct points, they can be separated two disjoint  open sets, since the main space is totally disconnected (see Theorem at <  >).   Is this argument true?


am coming back from Sudan to Canada and I have a 6 hours layover in Amsterdam  and I have a Canadian travel document do I need a visa there


How to justify a very long ciphertext and corresponding plaintext in Latex?

I have a very long ciphertext and corresponding plaintext both are of 680 alphabets without space to print in a latex document. I have not found any way to make justify it in internet. Any Ideas please?  Text is like as follows without any space:  RFROSERHUKEITFRIZXHVNVSIRLCJPWGSYVSMGKIOPEBUWCDEZZTVWIGKATEPSUWJPRGYEJPEFUHGCZCZCGNPCJEVZLSIECCCCLRGELWEKKYKOSOWEWCDEVSMBXMAOIOIAPOXVRTOLOSJYQFJCIGGEXCKANVMQRNVEIZCYQFNIJTPZAKYAVELSDOTLPCWTJLXWJBWEMGYANWVSDEOMIFZTKYEPZTRPVVRPUTXVRSPESBVANTGSMEPEYFVDVZVSDATVXIKTWEGVZLFDEWUTJPHITHGDWSMETJXVZNIDKCKAOZVOCIHZRZPYQFGOEFKYHWKAPOWVVSSFISQEFSIFJENQYDTLQDIFKOCWMQVSUTHSRSUSIGGOMPEZZCGOMREOVXYQYLKVIYVERTRUJOEWSGVTQSIFWITDXPVCCFWSKHGOYQYEUDAOJVGCCIXLALRRJEEZRRCYDPGOLSGDLSNAUPBOTTNJXVVRKRLHYEKRLHKOTPWHYETNLWEURZROCIEPWGYOWWHSIAPOMHNAULRIECQXJCITCMPMJHCCTQYIPSSKVVGCWVVDKORCKLKVIHFBGCYRVSQDLSSOTPMHRSYPPZRSUSIQFUNOXVVGCXIGXOKYKCERCELSIBGEXSINQHWVVSCTHPPWCJSTBEGAMBXURELSTOPGIFJAVTSBRLKEXZV


I've seen its proof in Bartle and Sherbert.  But, I think a lot more interesting proofs of this can be done. Plz, help me in writing its proof in other possible ways. So, that I can develop more constructive ideas for building proofs of such type in future.  Thanks in advance. Plz write.


What do people usually wear to conferences?

I'm going to my first conference in about a month, where I will be presenting a poster.  How do people usually dress for conferences? Do I need to dress more smartly than usual? Is formal dress (e.g. a suit) normal? Or does no-one really care?  I'm a PhD student, if that makes any difference, and both my university and the conference are in the UK. It's a biology conference.


I am using Sony Vaio and laptop charger burned its rating was 19.5V-3.9A, i am trying to find the same model but I have been only been able to find one with the rating 19.5V-4.7A. Can I use this, any pro's and cons. FYI my battery has already worn out!


Does the Planck scale imply that spacetime is discrete?

On a quantum scale the smallest unit is the , which is a discrete measure.  There several question that come to mind:   Does that mean that particles can only live in a discrete grid-like structure,  i.e. have to "magically" jump from one pocket to the next? But where are they in between? Does that even give rise to the old paradox that movement as such is impossible (e.g. )? Does the same hold true  for time (i.e. that it is discrete) - with all the ensuing paradoxes? Mathematically does it mean that you have to use difference equations instead of differential equations? (And sums instead of integrals?) From the point of view of the space metric do you have to use a discrete metric (e.g. the ) instead of good old Pythagoras?   Thank you for giving me some answers and/or references where I can turn to.  Update: I just saw this call for papers - it seems to be quite a topic after all: Is Reality Digital or Analog? FQXi Essay Contest, 2011. , , . One can find some pretty amazing papers over there.


Web scrape (or similar) html code from an ip address via Javascript

Currently have a Zebra printer which currently has its own IP address. When you visit the ip address via Chrome, it provides you the status of the printer (see attached).   I am wondering is there a way to   Is there any javascript library (or native code) that people recommend that could do this?


All is in the title: Is $\langle a,b \mid a^2b^2=1 \rangle$ a semidirect product of  $\mathbb{Z}^2$ and $\mathbb{Z}_2$? I think it is the case, but I don't know how to prove it.


What's difference between inner join and outer join (left join,right join), and which has the best performance of them?  Thanks!


Are there any disadvantages to always using nvarchar(MAX)?

In SQL Server 2005, are there any disadvantages to making all character fields nvarchar(MAX) rather than specifying a length explicitly, e.g. nvarchar(255)? (Apart from the obvious one that you aren't able to limit the field length at the database level)


I have a DC voltage source (between 5 and 10V) from which I want to charge cell phone with a USB cable. I believe that using a LM317 or similar IC for charging cell phones is not a good idea as most cell phones are coming with Lithium-ion batteries, which requires constant current phase first, then constant voltage phase.    I have seen MAX1555 IC but it gives only 4.2 V as regulated output. If I connect a VBUS (usb cable) from MAX155 chip to iPhone, my iPhone may not charge because it's less than 5 V.  Can anyone give some insight?


TikzPoster - figure to the right, and wrapped text. Is it possible?

Is it possible to have a figure to the right of you text, and at the same time have the text wrapped around it? I've tried the package wrapfig, but doesnt seem to work. Any advice? sketch:  \documentclass{tikzposter}  \title{The Title} \author{The Author}  \usepackage{lipsum}   \begin{document}  \maketitle  \block{A Title}{  \lipsum    \begin{center} \begin{minipage}{0.45\linewidth}   \centering   \begin{tikzfigure}[Caption of figure1]   \includegraphics[height = 10cm]{example-image-a}   \end{tikzfigure}% \end{minipage}\hfill \begin{minipage}{0.45\linewidth}   \centering   \begin{tikzfigure}[Caption of figure2]   \includegraphics[height = 10cm]{example-image-b}   \end{tikzfigure}% \end{minipage} \end{center} }    \end{document}


Is there another alternate way for getting input as bytes and swap them?

I am beginner to this programming and recently my teacher gave me a homework on swapping two bits in a byte. I could not figure out how to do so i referred to a website where there was an answer for that. The thing is there they gave a fixed input but I want to get input at runtime and swap bits in that.But I am receiving same output for every input My code is #include <stdio.h>  int main() {     unsigned char data;     printf("Enter hex number: ");     scanf("%c",&data);     unsigned char bit_1 = (data >> 1) & 1;     unsigned char bit_2 = (data >> 2) & 1;     unsigned char xor_of_bit = bit_1 ^ bit_2;     printf("After swapping the bits, data value is: %2X", data ^ (xor_of_bit << 1 | xor_of_bit << 2));     return 0; }  My input was 0xA and my ouyput was 30


Python pyproj converting from WGS84 to Israel Grid IG 05/12

Now I see this is duplicate and is answered in  I am trying to translate coords from WGS84 (file collected using a GPS) to ITM in Israel. I am testing the code by comparing results with the station points in the official documentation to see if working correctly and there are small differences. So what is missing? Where is the mistake? ALON RESULT:   624087.942N 162790.452E Expected: 624088.355N 162789.564E  My code: from pyproj import Transformer  stril2012 = '+proj=tmerc +lat_0=31.7343936111111 +lon_0=35.2045169444445 +k=1.0000067 +x_0=219529.584 +y_0=626907.39 +ellps=GRS80 +towgs84=-24.002400,-17.103200,-17.844400,-0.33009,-1.852690,1.669690,5.424800 +units=m +no_defs' stril = stril2012 transformer = Transformer.from_crs("epsg:4326", stril) #ALON STATION lat =  (28.569400 / 60 + 42) / 60 + 31 long = (23.921960 / 60 + 36) / 60 + 34 alt = 55.671 res = transformer.transform(lat, long, alt) print("ALON") print('RESULT:   {:010.3f}N'.format(res[1]), '{:010.3f}E'.format(res[0])) print("Expected: 624088.355N 162789.564E")


Were Batman's phones used to map surroundings using custom hardware? How did he distribute them?

In Nolan's Dark Knight, Batman (or rather Lucius Fox) develops a technology which allows using a phone as a mini-radar (I didn't quite catch if it was using EM like radar or sound like sonar, but given this is Batman I wouldn't be shocked if it was sonar).   Was this technology detailed anywhere as being hardware based or software based? If it was stated as hardware based, how exactly did Batman manage to equip pretty much everyone in the entire city with a new phone containing that hardware in the short time period that the movie takes place in? If it was software based, how did he download the software to both emit and receive the signals onto EVERYONE's phone without the cell companies objecting[1]?    I am looking for answers from canon (movie, script, DVD, delete scenes); creative team interviews; or if there are specific DC comics that Nolan based the movie on, I'm ok with answer from those specific comics if it matches up to the movies.  [1] If it was software, I would accept an answer listing the (canon) fact that Wayne was a major cell carrier in Gotham  h/t: Based on a comment on another post.


what is this para about on function objects

I came across this statement in a book and I don't understand it. The sentence is: "The templates in <function> help you construct objects that define operator(). These objects are called function objects and can be used in place of function pointers in many places".  Please tell me what operator() is, and I would also like some help in understanding what "function object" mean in this context.


Is $\langle A,B\rangle =\operatorname{trace}(AB^T)$ an inner product in $\mathbb R^{n\times m}$?

I don't understand why one should take transpose of $\operatorname{tr}(AB^T)$ and why we use the fact that $\operatorname{tr}(M)=\operatorname{tr}(M^T)$ for any $M$ that is a square matrix to solve the problem.


Why the principal value of complex number argument is taken within $(-\pi,\pi]?$ What is the harm in considering similar other intervals like $[0,2\pi)$ for the purpose?


I need to update the grub2 themes. I already removed unwanted entries in menu by editing grub.cfg file. Now I like to update or load the eye catching themes, I want to know whether any Linux application is available for updating themes or we want to do it manually. Please guide the process for both manual and application.


I'm finishing my Msc. Thesis and I'm facing the last problems with some tabular, I'm not able to align this one.  \documentclass[12pt,a4paper,oneside,openright]{book} \usepackage{adjustbox} \usepackage{array} \usepackage{dcolumn} \usepackage{amsmath,amssymb}    \usepackage{amsthm} \usepackage{booktabs}  \usepackage{caption}   \usepackage{multirow} \usepackage{siunitx}  \usepackage{tabularx} \usepackage{ltablex} \usepackage{makecell}  \begin{document} \begin{table} \centering \caption{Analisi variabile tasso di interesse\label{tab:stat:tasso}} \begin{tabular}{p{3cm}p{3cm}} \toprule Data di segnalazione & \makecell[ccc]{\% \\ Tasso di interesse\\ medio} \\ \toprule 2014h1 & 3.59\\ 2014h2 & 3.44 \\ 2015h1 & 3.37 \\ 2015h2 & 3.82 \\ 2016h1 & 3.68 \\ \bottomrule Media & 3.58 \\ \end{tabular}% \end{table}% \end{document}


How can I reliably determine if a file is an image file?

Currently I'm using the following command:  file image.jpg | cut -d " " -f 2   So far so good. It works on a file without an image extension too. So, I was wondering if there's another way to do this? I might have not seen a certain case where the above code would fail.  Edit: I am trying to create a script for renaming the image files in a directory sequentially.


Find expected value for $\max (X_1,...,X_n)$

I have a random variable $X$ behave as $ U[0,\alpha]$.  Out of $n$ experiments, I would look at the new random variable $Y=\max(X_1,...X_n)$.  I ask for $E(Y)$.   I know it supposed to be $\alpha \cdot \frac{n-1}{n}$ or something like that (maybe $\alpha \cdot \frac {n}{n+1}$) and I understand why, but all this is intuitive and I don't understand how to prove it.  Thanks in advance for your answers


The furniture in our classroom ___ uncomfortable.   Should I use is or are here? I found on the internet things like all of furniture is and house full of furniture is.  But nothing about my example. Personally I think that correct is is, but website where I found this says that correct is are. So I'm writing here to find out.


Consider this table in mysql  create table numbers (number int); insert into numbers values (3), (2), (9); select * from numbers;  +--------+ | number | +--------+ |      3 | |      2 | |      9 | +--------+   Is there a simple query to generate a table with the following columns   The numbers from 1 till 10 1 if the number is present in the table numbers, and 0 otherwise   I guess you have to create a sequence of numbers in order to do this. If possible, I want to create such a sequence without storing it in the database.  Related question: is there a select query that generates a sequence of numbers from 1 till 10 (or 100 or 1000)?


Is a suggested edit thrown out of the Queue when it is ignored/skipped?

What happens when a suggested edit is ignored/skipped?   Is it thrown out of the queue and how much time does it take to get out of the suggested edit Queue?


I need help resolving this error: E: Malformed entry 1 in list file /etc/apt/sources.list.d/nodesource.list (Component)

I've been trying to install the latest version of Node.js, but my terminal is throwing this error when I try to install. Any tips on how to resolve this would be much appreciated. thanks E: Malformed entry 1 in list file /etc/apt/sources.list.d/nodesource.list (Component)


How can I determine if a Win32 thread has terminated?  The documentation for  warns to not to use it for this reason since the error code STILL_ACTIVE can be returned for other reasons.  Thanks for the help! :)


I know this is (one of the) proper ways to create an Array of Objects in PHP:  $obj1 = new stdClass; $obj1->title = "Title 1"; $obj1->author = "Author 1"; $obj1->publisher = "Publisher Name 1";  $obj2 = new stdClass; $obj2->title = "Title 2"; $obj2->author = "Author 2"; $obj2->publisher = "Publisher Name 2";  $obj3 = new stdClass; $obj3->title = "Title 3"; $obj3->author = "Author 3"; $obj3->publisher = "Publisher Name 3";  $newArray = array($obj1, $obj2, $obj3); echo ($newArray[0]->title);   but in some other languages (JS,  ActionScript..etc) you can quickly create the object inside the array declaration like so:  var userArray = [{name:'name 1', age:'10'}, {name:'name 2', age:'11'}, {name:'name 3', age:'12'}];   generic, not named, no class objects.....  And then access it like so:  userArray[0].name    Is there a quick/shorthand way in PHP to do the same?  Or do you need to define an object name and instantiate it..etc  Like so: $obj1 = new stdClass;  and then move to assigning each property and then add to the array all in separate steps?


I am trying to solve question 4 in Munkres Analysis on Manifolds section 26.  The question is determine if the following is a tensor on $\mathbb{R}^4$ and express those that are in terms of the elementary tensors on $\mathbb{R}^4$.   $f(x,y) = 3 x_1 y_2 + 5 x_2 x_3$   I am trying to follow the definition of a tensor (which I don't think I fully understand) to show this. I know I must find a function $T: \mathbb{R}^4 \rightarrow \mathbb{R}$ that is linear on the $i^{th}$ variable. Since there are only 2, then I believe I have to somehow write $f$ as a projection. I'm just not sure where to  go from here.  Any hints would be great, thanks!


Pakcage "apache' has no installation candidate

I'm trying to install Apache into Ubuntu Desktop 18.04.1, but retrieving the error: package apache2 has no installation candidate Any help, please? Thanks!


The following Problem occurred. If i try to login per CL (pressed Ctrl+Alt+F1), i can enter my Username after pressing enter it skips the pw field and after 3 sec. it tells me login incorrect. After that it skips the login field and tells me login incorrect for 4 more times.   Ubuntu 18...  Laptop-01 login: asd Password:  Login incorrect Laptop-01 login:  Login incorrect Laptop-01 login:  Login incorrect ...   I can login per GUI and access everything, switch Users in the shell ...


Evaluate $\int_{0}^{1} \log^2(x)\log^2(1-x)\,dx$ using non-elementary methods.

The task is to evaluate, using the specific given hint, and only real-analysis methods, no complex analysis is allowed in the problem. $$\int_0^1 \log^2(x)\log^2(1-x)\, dx$$ The hint given is: $$ \sum_{k=1}^{\infty} (H_k)(x^k) = (-)\frac{\log(1-x)}{1-x},$$ where $H_k$ is the harmonic number.  If we integrate both sides we get.  $$ (2)\cdot\sum_{k=1}^{\infty} \frac{(H_k)(x^{k+1})}{(k+1)} = \log^2(1-x)$$ Recalling the hint: $$\sum_{k=1}^{\infty} (H_k)(x^k) = (-)\frac{\log(1-x)}{1-x}$$ Substitute $x \to 1-x$ $$\sum_{k=1}^{\infty} (H_k)((1-x)^k) = \frac{-\log(x)}{x}$$ Integrate both sides to get: $$(2)\cdot\sum_{k=1}^{\infty} (H_k)\frac{((1-x)^{k+1})}{k+1} = \log^2(x)$$  I think it is a good idea to evaluate the sums differently.  Or simply, $$\log^2(x)\log^2(1-x) = \left[(2)\cdot\sum_{k=1}^{\infty} (H_k)\frac{((1-x)^{k+1})}{k+1}\right]\left[(2)\cdot\sum_{k=1}^{\infty} \frac{(H_k)(x^{k+1})}{(k+1)}\right]$$  But that would result in quadruple sums... Any ideas?


Possible orders of permutations of $11$ symbols

Which of the following numbers can be orders of permutations $\alpha$ of $11$ symbols such that it does not fix any symbol ? $1.$ $18$, $2.$ $30$, $3.$ $15$, $4.$ $28$


I had some personal info shown on my profile, and I removed it.  I'm just curious: Does a record of profile revisions, much like post revision history, exist?  If so, who can access it? Mods? Devs? Anonymous users :p?


So, as your usual physics undergrad, I read Griffiths's derivation of the general   uncertainty principle. I understood it but there was no physical intuition given behind it in the book. It was basically a bunch of manipulations and inequalities used to get just the right result.  Other than "It's because of the statistical interpretation." is there a more intuitive reasoning behind uncertainty. Like commutators, behavior of particles, etc.  Thank you for the replies and as always, much obliged.


Can't download into /media/.../MyDisk (NTFS) - Permission denied

I'm trying to set my disk as a download folder for qBitTorrent. The problem is that when I'm trying to choose /media/milano/Milano Disk - here is my disk mounted. But nothing is being downloaded and when I try to open the folder using qBitTorrent it says:  Which is weird because qBitTorrent is running under milano user and Milano Disk has these permissions: milano@milano-desktop:~$ ls -la /media/milano/ total 24 drwsrwsrwx+ 3 root   root    4096 lis  7 16:19  . drwsrwsrwx  3 root   root    4096 dub 11  2020  .. drwxrwxrwx  1 milano milano 16384 zář  7 23:57 'Milano Disk'  Do you have an idea where is the problem? The same problem is when I try to use a different disk to be the destination.


Linear transformation for matrix using Einstein convention

I feel like I am stuck. How can I interpret the equation with Einstein summation? Here is the exercise:      you should see that r′ can be written as a linear transformation of r. This means we should be able to write r′=Ar for some matrix A.    The exercise is depicted on the picture.   I will be more than thankful if someone explains that to me in minute detail.


If Γ is a closed Jordan curve that encloses a region with area A, show that  $A=\frac{1}{2i} \int_{\Gamma} \overline{z}dz$. Then show that $A=\frac{1}{2i} \int_{\Gamma} \overline{z}dz$ can be written as $A=\frac{1}{4i}\int_{\Gamma}\overline{z}-z d\overline{z}$. I have no clue where to start here.


What does observation mean in two-slit electron diffraction experiment?

My question is clear, that I ask: What do we mean by "observation" in 2-slit experiment for electrons (or any other wave-particle)?  You know, we say that :"if we observe the electron, it shows a particle-like behavior; and if we do not observe it, it shows a wave like behavior"  So, if the observation is through sending and getting photons, is it just through our eyes or through any other interruption by light beams? I'm confused! Or if my sentences are silly, what's the correct approach to understand the term observation?


How to use django variable in Javascript?

I'm trying to associate a button with a dynamic url with the following javascript: <script type="text/javascript">     var name = {{pp.name}};     var url = "{% url 'editproject' %}";     document.getElementById("myButton").onclick = function () {      location.href = url + "/" + name    }; </script>   But I am getting an error when I try to click on the button. pp.name is a django variable that would return the name of the project, and the url I'm trying to access is path('editproject/<str:name>/', p.update, name="editproject"),


How can you disable the low battery warnings for bluetooth devices?

I use a bluetooth apple trackpad and keyboard, and once the battery hits 20% the bluetooth indicator in the menu bar starts flashing this lower battery warning. Normally, I wouldn't really care, but 20% battery is about 1-2 months of usage so the thing just flashes at me constantly for over a month.  Is there a way to disable this behavior?


Calling unspecified function from another file and another class

I am trying to call an uncertain named function from another class. I mean, external input or a variable in a loop as a function name.  For example;  class options(object):      def functionOne(): # or function1         pass     def functionTwo(): # or function2         pass     def functionThree(): # or function3         pass   in a options.py file and either:  class main(object):      def runSomething():          options=options()         while counter<=3:             options.function**"a"**()             counter = counter+1   or:  class main(object):      def runSomething():          options=options()         num=raw_input("number: ")          options.function**"num"**()   in the main.py.  What should I put at the bold places? Is there any way to combine function name and number in order to call function.  I have been looking for a solution to this problem for days, but I cannot find any relevant solution.


preg match all chars and whitespaces included

I want to match everything starting from the line /Subtype /Widget until the line <<  With this code nothing is matched  preg_match('#/Subtype /Widget([.\s]*)<<#', $pdf, $matches);   subject  522 0 obj  << /Subtype /Widget /V (some text) /T (Kreditor) /Rect [54.6 359.16 296.4 531.84] /P 414 0 R /DA (/Helv 8 Tf 0 g) /Ff 8392704 /Type /Annot /F 4 /TU (Kreditor:) /AP  << /N 534 0 R


How can a transistor burn out controller?

If a transistor works as a 'switch' and I turn it on using a controller (Arduino), how can I burn the controller?  I pass a 5v, 0.02A charge from my Arduino controller to transistor's base. The transistor opens and lets the electricity flow from the collector to the emitter powering on my other larger 40v device.   Can the current get in from the collector into the base? What's the reason for adding a resistor between the controller and the base? so that I don't add 'extra' current from Arduino into the other devices chain? Thanks!


Insert number into String fast, by .format or .replace?

I just want to set a placeholder in a String to a running number in a big loop. For convenience the placeholder is %d. What is faster, using String's .format or .replace method?


How to remove VirtualBox from Ubuntu permanently?

I need help removing VirtualBox from my computer.  I've already tried:  sudo apt-get remove virtual-box-* sudo apt-get purge virtual-box-*     it just said it was selecting some stuff and then it said it didn't remove them and commented:  linux-image-generic : Depends: linux-image-4.4.0-87-generic but it is not going to be installed  linux-signed-image-4.4.0-79-generic : Depends: linux-image-4.4.0-79-generic (= 4.4.0-79.100) but it is not going to be installed  linux-signed-image-4.4.0-87-generic : Depends: linux-image-4.4.0-87-generic (= 4.4.0-87.110) but it is not going to be installed   E: Unmet dependencies.   Try 'apt-get -f install' with no packages (or specify a solution).


I was musing about electric motors after seeing one randomly on TV, and there's something I'm must be remembering incorrectly.  It's just a thought experiment, so I'm imagining some theoretical DC electric motor, with a constant RMS current/voltage feeding in, and some constant load on it causing it to spin at some constant rpm and produce some constant torque.  Since voltage x current = electrical power = motor's mechanical power, that's the cap on how much you can get out of the machine.   But I remember that the greater the difference in rotational speeds between the rotor and stator fields (slip?), the more force/torque will be exerted on the rotor.   So in the hypothetical, if the motor is doing its thing and is stable with the load, if you suddenly increased the frequency of the input voltage/current, that in my mind would result in suddenly increasing the difference in relative rotational speeds of the stator/rotor, meaning the stator would feel more force/torque on it, which would make it want to speed up and catch up to the stator field, speeding up the load.  But only frequency changed and not how much electrical energy is entering the device, so there's no way that's possible! So I MUST be wrong, I just don't see where the error in my thinking is...  What's wrong with my thinking, and what would actually happen if you increased the frequency like that?  (I'm not an electrical person by trade, so there's a limit to my knowledge of concepts/terminology.)  [EDIT: I failed to mention that by "frequency", I'm referring to how DC motors can be controlled with pulse width modulation, and those pulses go in at some frequency. Otherwise it wouldn't make sense to talk about "frequency" with direct motors]


How to avoid TeXstudio highlight as wrong some commands?

It could be a dummy question, but I'm a little obsessive with the order and organization. I use TeXstudio as editor, so when I call the packages, generally the commands associated to them appears as suggestions when I write. However, TeXstudio mark as wrong some commands even when I called the package. There are 2 examples for the packages siunitx and makecell:  Here, the command \makecell from makecell package appears as wrong and the centimeter option \cm from siunitx too. It's important to say that I have no problems compilating, it's just an obsession.    How can I let TeXstudio to recognize this commands (and others that I can't remember) and show them in the siggestions too?


javascript - Get name of function through a function

So say, I have function Hello_world() :  function Hello_world() {   b(); }   I want to create function b() where b() returns the name of the function in which called it. In this case I want b() returns "Hello_world".  So how should b() be constructed? Thx.


arbiter bring down the three node mongodb replica set

I have a typical 3 node mongodb replica set. One primary, one secondary and one arbiter. I thought the replica set would survive one node offline but it didn't. Please help me understand what went wrong.  Here is what I observed. Are they supposed to work like this?    When I take the arbiter offline (killing the instance), both two data nodes become secondary (they were primary and secondary). When I take the primary offline (killing the instance), the secondary and arbiter remains secondary and  arbiter. There is no voting to select the new primary.   Thanks!  Here is the config  {   "_id": "0",   "version": 8,   "protocolVersion": NumberLong(1),   "writeConcernMajorityJournalDefault": true,   "members": [     {       "_id": 3,       "host": ":27017",       "arbiterOnly": true,       "buildIndexes": true,       "hidden": false,       "priority": 0,       "tags": {        },       "slaveDelay": NumberLong(0),       "votes": 1     },     {       "_id": 4,       "host": ":27017",       "arbiterOnly": false,       "buildIndexes": true,       "hidden": false,       "priority": 0,       "tags": {        },       "slaveDelay": NumberLong(0),       "votes": 0     },     {       "_id": 5,       "host": ":27017",       "arbiterOnly": false,       "buildIndexes": true,       "hidden": false,       "priority": 3,       "tags": {        },       "slaveDelay": NumberLong(0),       "votes": 1     }   ],   "settings": {     "chainingAllowed": true,     "heartbeatIntervalMillis": 2000,     "heartbeatTimeoutSecs": 10,     "electionTimeoutMillis": 10000,     "catchUpTimeoutMillis": 60000,     "catchUpTakeoverDelayMillis": 30000,     "getLastErrorModes": {      },     "getLastErrorDefaults": {       "w": 1,       "wtimeout": 0     },     "replicaSetId": ObjectId("")   } }


Can players perform checks using Ability modifiers?

To be broad here: Can Players use Ability Score Modifiers to add to their checks?  For example: can someone make a "Strength" check. (Not an Athletics Check) to, perhaps, break open a chest with force.


Biber exiting with error code 2 but no error messages

I get the following output (terminal output and blg log file) from running biber build/essay. It fails with error code 2 but doesn't give any error message... how helpful! [0] Config.pm:311> INFO - This is Biber 2.16 [0] Config.pm:314> INFO - Logfile is 'build/essay.blg' [120] biber-darwin:340> INFO - === Mon Jan 18, 2021, 04:53:13 [148] Biber.pm:415> INFO - Reading 'build/essay.bcf' [337] Biber.pm:949> INFO - Using all citekeys in bib section 0 [365] Biber.pm:4340> INFO - Processing section 0 [385] Biber.pm:4531> INFO - Looking for bibtex format file 'essay.bib' for section 0 [388] bibtex.pm:1689> INFO - LaTeX decoding ... [403] bibtex.pm:1494> INFO - Found BibTeX data source 'essay.bib'  Things used to run fine, but randomly stopped working. Here's my (sample) . Update It seems like the biber run passes when I remmove all numeric fields from the file (e.g., year, volume, number)... odd!


What is the difference between "property" and "attribute"?

This question has been , but I am not satisfied with the answer. In the course of researching this I developed a theory and now I am unable to verify whether this might be true or against common usage because I am not a native speaker. I will just give an example because formulating it in general is more confusing than helpful.     Jeff Atwood has the attribute black for the property hair color.   So a property (hair color) is a thing belonging to a class (human) while instances of a class (Jeff Atwood) have a concrete attribute (black) associated with this property.  Does that sound reasonable or unlikely?


When an electron moves from lower potential to higher potential and the work done by electric force is positive.   Therefore we will conclude that whenever a negative charge moves from a lower potential to higher potential, work done by electric force is positive and when a positive charge moves from lower potential to higher potential the work done by electric force is negative. Why? What is the concept?


I downloaded manually cntformats.sty and put it in the directory exsheets. But Latex still doesn't recognize it and asks if I want to download it. I tried several times to download it by changing the location of links through latex, but the message "not found" is always returned.  I greatly appreciate your help. Thank you


I am trying to insert some data to textview(In fragment) from database. Here is the fragment:  SQLiteOpenHelper deck_helper = new DeckDatabaseHelper(getActivity());     SQLiteDatabase db = deck_helper.getReadableDatabase();     TextView name = (TextView) getActivity().findViewById(R.id.textView2);     Cursor cursor = db.query("DECK", new String[]{"NAME"}, "_id=?",             new String[]{Integer.toString(1)}, null, null, null);         try {              if (cursor.moveToFirst()) {                 String nameText = cursor.getString(0);                 name.setText(nameText);              }             cursor.close();             db.close();         } catch (SQLException e) {             Toast toast = Toast.makeText(getActivity(),                     "Database unavailable", Toast.LENGTH_SHORT);             toast.show();         }   And DeckDatabaseHelper   public void onCreate(SQLiteDatabase db) {      db.execSQL("CREATE TABLE DECK (" + "_id INTEGER PRIMARY KEY AUTOINCREMENT, "             + "NAME TEXT, "             + "CLASS TEXT, "             +  "IMAGE_CLASS INTEGER"             + ");");     ContentValues values = new ContentValues();     values.put("NAME", "Mage");     values.put("CLASS", "Mage");     values.put("IMAGE_CLASS", "123");     db.insert("DECK",null,values);  }   I think that Textview should show "Mage", but get this error     java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference                                                                                at com.example.nikolaypavlin.deck.Fragments.DeckManagerFragment.onCreateView(DeckManagerFragment.java:54)   I am sure that textView2 exists  <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.nikolaypavlin.deck.Fragments.DeckManagerFragment">  <!-- TODO: Update blank fragment layout -->  <ListView     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:id="@+id/listView"     android:headerDividersEnabled="false"     android:visibility="visible" />  <Button     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="New Button"     android:id="@+id/button"     android:layout_gravity="right|center_vertical" />  <TextView     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:textAppearance="?android:attr/textAppearanceLarge"     android:text="Large Text"     android:id="@+id/textView2"     android:layout_gravity="right|top" />


Is there an English idiom for trying to do two things at the same time and failing at both of them due to splitting your effort?

I'm basically searching for the opposite of putting all your eggs in one basket, where the risk is total failure because you did not hedge your efforts. I'm searching for a phrase that encompasses splitting your efforts and evokes the prospect of failing at both. A bird in the hand is worth two in the bush also encompasses a sense of having focused your efforts, but only alludes to total failure. To satisfy the criteria, the phrase must cover:  attempting two things (or multiple iterations of one thing) both of which you might succeed at, if you addressed them serially but both of which you fail at because you address them in parallel  Here are the idioms/phrases that do not sufficiently cover the idea and why:  "A servant to two masters"  This has the sense of competing priorities, but not the sense of failing to achieve your goals.  "Jack of all trades. Master of none."  The sense is insufficiently pejorative. Being a jack-of-all-trades can be seen as an advantage; I'm trying to focus on the lack of mastery.  "The man who fancied himself a wit, and was half-right."  From Christopher Hitchens. Hilarious, but lacking the sense of split effort between two things.  "Walking and chewing gum at the same time."  An idiom for multi-tasking, not for failing to multi-task. Edit Addressing a few suggestions and another one that occurred to me:  "Hedging your bets" or "Betting against yourself"  In this case, you cannot win both bets, but you will almost certainly win one. You limit your upside, but also limit your risk. I'm looking in particular for total, catastrophic failure due to split attention/effort.  "Can't walk and chew gum at the same time"  Failing to do two fairly simple things that most everyone can do, not failing at two hard things because you tried to do both.  "Robbing Peter to pay Paul"  In this case, Paul gets paid. If you were to rob Peter to pay Paul, and get robbed yourself before you could get the money to Paul, that'd be closer. :)  "Spreading yourself too thin"  An actual English idiom, but missing the implied sense of failure.  "Too many irons in the fire"  "A lot of irons in the fire" can be viewed positively, so this is missing the sense of a strategic misstep.  "Between a rock and a hard place"  The sense is of needing to act but having no good alternative.  "Falling between two stools"  My favorite answer so far because it does appear to be an actual English idiom (not a proverb). In that sense, it's great, but some of the usages are closer to a failure of  than a failure of effort. And falling between two stools implies that the attempted action was simply sitting down.  "Chasing two rabbits and catching none."  This is the exact sense I was looking for, but it appears to be a cross-cultural proverb rather than idiomatic English like "putting all your eggs in one basket". I'll be accepting it, and using it in my work! But if there are other ideas, please let me know.


How do I find an invertible matrix $P$ such that $P^{-1}AP$ is upper triangular?  $$A=\begin{pmatrix}-3 & 1 & -1\\-7 & 5 & -1\\-6 & 6 & -2\end{pmatrix}$$   I can't really find a good general method for doing this online.


Proverbs similar to "We're not rich enough to buy cheap things"

I'm looking for other proverbs similar to "We're not rich enough to buy cheap things". This is because I want to use it for a similar but a little bit different purpose. I want it to be meant that to get something valuable you must pay more than the price that is common place.


Set of functions from $SS = \{ A_{1}, A_{2}, A_{3},...\}$ to $\{ \mathbf{T}, \mathbf{F} \} $ is countable?

Let $SS=\{ A_1,A_2,A_3,\ldots\}$, and let $V = \{ v \mid v: SS \to \{ \mathbf{T}, \mathbf{F} \} \}$ .Is the set  V countable?  Justify your answer. My instinct is to say that $V = \{ v \mid v: SS \to \{ \mathbf{T}, \mathbf{F} \} \}$ is uncountable, and to prove this using a diagonalization argument, i.e. create a table of values of the functions $v_{1}, v_{2},...$ for natural numbers $n_1, n_2,\ldots$ and define a function $v_{m} : SS \to \{ \mathbf{T}, \mathbf{F} \}$ where it takes all values in the diagonals of the table $T, F$ and flips them, and then show that $v_{m}$ cannot appear anywhere in the list. Is my guess correct, and if so would this be a reasonable approach to the problem?


pdf of a quotient of uniform random variables

Suppose $x_1, x_2$ are IDD random variables uniformly distributed on the interval $(0,1)$.  What is the pdf of the quotient $x_2 / x_1$?


C# .NET - Sending large number of small messages (over network) with minimal latency

I'm trying to find an optimal solution for sending large amount of small messages (usually around 1000 per sec, can be up to 10000 per sec. Each message is up to 1KB large), over the internet, but with minimal possible latency (think e.g. about financial data). I started with basic Duplex WCF channel - that was great for local network. Than I needed to change my contract to be oneway (OperationContractAttribute with IsOneWay property set to true), as otherwise each message waited for confirmation and so network latency was counted twice for each message. Even after this my service still sometimes doesn't catch up (and on the server side I'm just reading messages from the queue and immediately sending, on the client side I just enqueue message after receiving and do not block).  I'm wondering if there is some overhead caused by sending large number of small messages. Is there a better way (e.g. some sort of streaming over TCP)?  Edit1: Based on feedback I'm adding little technical info:  Our service is in Singleton instance mode that can be called concurrently ([ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)]).  We didn't configure throttling so it has default values (however there is just very few concurrent clients - 1 to 4)  In fact we use duplex channel - client calls in (registers) and then server is sending large amount of messages to client. Client itself performs very little calls. Server calls the client via callback Channel in synchronized way (we iterate through blocking queue), however very, very frequently (those mentioned ~1000 messages per sec, but even few thousands per sec).  Edit2: Explaining why this is not a duplicate to  question:  In our scenario we actually have very small number of clients (let's even consider just one single client), but large number of messages being continuously sent to that one client - so it's something like streaming scenario.  We already did the measurements of typical client scenario and service throughput and found that we currently cannot scale well in some situations (for over-the-internet client at the short times in day when there is larger number of messages needed to be sent - then those are probably queued by WCF as we temporarily see increasing delay in receiving time).  Scaling out to multiple server boxes isn't unfortunately viable solution for us (one client need to be connect to one server for whole day).