Since we can not assign null value to integer type variable. So I declared int? type variable and used ternary operator and tried to pass the variable as parameter. But getting error.  int? SAP = 0;  SAP = SAP_num == null ? null :Convert.ToInt32(SAP_num);  // SAP_num is string   While trying to do this I am getting error, type of conditional expression can not be determined because there is no implicit conversion betwen '<null>' and 'int'  Then I tried   int? SAP = 0; SAP  = Convert.ToInt32(SAP_num); int confimation_cd = GetCode(SAP);   while trying to do this getting error,cannot convert from 'int?' to 'int' GetCode function accepts integer.  My problem is, if the SAP_num IS NULL , pass as null in the function GetCode else pass as integer value. How to achieve this?

EmployeeNumber = string.IsNullOrEmpty(employeeNumberTextBox.Text)     ? null     : Convert.ToInt32(employeeNumberTextBox.Text),  I often find myself wanting to do things like this (EmployeeNumber is a Nullable<int> as it's a property on a LINQ-to-SQL dbml object where the column allows NULL values).  Unfortunately, the compiler feels that  There is no implicit conversion between 'null' and 'int'  even though both types would be valid in an assignment operation to a nullable int on their own. Using the null coalescing operator is not an option as far as I can see because of the inline conversion that needs to happen on the .Text string if it's not null. As far as I know the only way to do this is to use an if statement and/or assign it in two steps.  In this particular case I find that very frustrating because I wanted to use the object initializer syntax and this assignment would be in the initialization block... Does anyone know a more elegant solution?


I'm looking for a book series I started but never finished 20+ years ago.  It was about a group of colonists who ended up on an inhabited planet.  Some, maybe all, of the characters were sent there as punishment for crimes.  The main character's name was Cord, he was really strong.  The villain's name was Lamprey, he was violent and had been in some kind of special ops military group back on Earth.  The native inhabitants of the planet were peaceful and not particularly dangerous, if I recall correctly.  Looking for this on Google has taught me much I didn't know about the spinal cords of lampreys and other fish, but no luck finding the book I'm after.

I'm trying to identify a book (or possibly a series, as I seem to recall reading a sequel which still left the story unfinished).  I read the book or books in the early 90's and had picked them up from a jumble sale at school, so they were probably published in the 80's or possibly 70's. I guess you would class them as YA fiction, though that wasn't really such a thing back then...  As I recall the story began with a slave transport craft crash landing on an alien world, with only a handful of teenage and pre-teen humans surviving. They scraped together what they could, including a couple of functional 'sunguns' (basically, laser rifles) and began a low level guerilla rebellion against the alien race that were using humanity as slave labour on the planet.  I've googled 'sungun' repeatedly, thinking that this should be the best way of finding the story but the references that come up are all for other stories or conspiracy technologies.  Anyone got any vague recollections of a book or series like this?


Suppose Mark and Paul are sitting on a table, and Mark starts tossing an unbiased and fair coin. He tosses it for 99 times, and he gets 99 consecutive tails. At this point Mark asks Paul: "let's bet $100 on the next toss, do you want to pick tail or head?"  Question: In order to maximize his expected return, should Paul pick tail, head, or it doesn't matter?

A two-sided coin has just been minted with two different sides (heads and tails). It has never been flipped before. Basic understanding of probability suggests that the probability of flipping heads is .5 and tails is .5. Unexpectedly, you flip the coin a very large number of times and it always lands on heads. Is the probability of flipping heads/tails still .5 each? Or has it changed in favor of tails because the probability should tend to .5 heads and .5 tails as you approach an infinite number of trials?  I understand that flipping coins is generally a stochastic process, but does that change at all if you see a large number of trials bias to one side?


The military units in SC2 almost all have counters (i.e. Thor counters Siege Tank). There are a lot of military units, so it makes it hard to remember all the counters. Is there an easy way to remember what counters what?

I find myself clicking on the "Help" button at the top of the screen to figure out Rock-Paper-Scissors counters on the fly. The Help system is nice, but I'd prefer if there were some easier way to quickly learn what counters what without having to memorize an .  I recall in Warcraft III, there were different types of damage and armor, like "Piercing" and "Siege" or something.  If such a thing exists for StarCraft 2, it might be what I'm looking for.  How can I learn my StarCraft 2 unit counters quickly?


I installed Google Earth Pro using the .deb package. Now I am struggling to find where it is installed. Where do .deb packages get installed in Ubuntu 20.04 LTS?

For some applications its fairly easy enough to locate where the application was installed to using the "which" command.  However, some applications such as Tomcat are a little out of my league to locate.  I'm asking for particular methodology that can be applied to any apt-get install  to locate where the binary, library, and support files are installed to.  The cause of this question is that I installed Tomcat7 and I can's seem to locate it and I have a list of customizations to perform.


How much have I broken and should I just reinstall the OS?

I accidentally removed all the packages starting with the name jpeg with:  sudo apt-get remove jpeg*   This screwed up a lot of things, removed Unity, Firefox, Flash player etc.  I somehow managed to recover the desktop and unity but then a lot of things are still buggy. For example .rpm files and .tag.gz just won't open up at all.  What I want is a way to fix everything that's amiss. Something that is the equivalent of a 'repair installation' with a windows disc.  Any tips, anyone?


Problem Statement:- Let $y=3x-8$ be the equation of tangent at the point $(7,13)$ lying on the parabola whose focus is at $(-1,-1)$. If the latus rectum of parabola is $k$ then find the value of $\lfloor{k^2}\rfloor$.  I could not think of much on this, but I did the find that the image of focus of the parabola w.r.t any tangent lies on the directrix by messing around in geogebra. Some hints to this problem would be great.

Let $y=3x-8$ be the equation of tangent at the point $(7,13)$ lying on a parabola, whose focus is at $(-1,-1)$. Evaluate the length of the latus rectum of the parabola.     I got this question in my weekly test. I tried to assume the general equation of the parabola and solve the system of equations to calculate the coefficients with the help of these given conditions. But this way it becomes very lengthy and tedious. Can anyone provide an elegant solution? Thanks.


Why do reviewer block improvements of tag wikis, which just fix spelling and broken links? Is it more important to have larger edits than better content? And why is there no flag option to report such cases?   Example:    If the reason is that some reviewers are bored accepting smaller fixes, what could be done to ensure that improvements are not stopped by the moods of these community members?

I just edited someone's post so that it would be more readable.  Basically, I just added some line breaks and spaces into their sql code so that it now takes a reader about 5 seconds to comprehend what the query is doing instead of 50.  It was rejected on the basis that the edit was too minor.  I respect that decision in that if there's a rule that minor edits should be rejected then they were following that rule.  I am just curious to know why that is a hard rule.  Is it just to prevent having too many edits?


I have created a script which includes the below.  The idea is to go through a list of excel files (Countries) in a folder and then, if it exists already to pass through and ignore, if it does not exist then to create it. In both cases, it will then move on to the rest of the script. I want to create it this way because I do not want to overwrite the other countries files every time as there will be data dating back a few months in each file (so overwriting will lose this). I would like to just create a new file for when one new country gets added to the list.  I cannot just create a file manually, as the rest of the script takes into account all files.  if ''.join(Countries) in path:     pass else:     for x in Countries:         workbook = xlsxwriter.Workbook(path + x)         worksheet = workbook.add_worksheet(sheetname)          FirstSheet = ([firstMes])          row = 0         col = 0          for y in (FirstSheet):             worksheet.write(row, col, y)             row += 1          workbook.close()

How do I check whether a file exists or not, without using the  statement?


To list all docker repositories I need to use an asterisk. But I am forced to add quotes because zsh globbing catches the asterisk.  sudo docker image list "hub.local/*"   I try aliasing with noglob, but sudo will fail, and docker needs sudo  alias docker="noglob docker"   I thought I could set zsh to not complain when it fails to match, but it seems zsh will remove the asterisk anyway.  setopt nomatch   I want to either disable zsh globbing entirely, or get zsh to pass through the globbing character if it fails to match. Or possibly set zsh globbing to behave like bash. I want to get around typing quotes all the time.

Using zsh, I get a "No match found" message when choosing a pattern that does not fit with rm and that even when redirecting the output.  # rm * > /dev/zero 2>&1   zsh: no matches found: *   How can I get rid of this message?


Why are there two different post notices applied to duplicate questions? One has an edit link, and one doesn't. Which one is applied to which questions?  This notice:     marked as duplicate by OneUser, TwoUsers, ThreeUsers, FourUsers, FiveUsers      This question has been asked before and already has an answer. If these answers do not address your question, please .   vs. this one:     marked as duplicate by OneUser, TwoUsers, ThreeUsers, FourUsers, FiveUsers      This question has been asked before and already has an answer. If these answers do not address your question, please  to explain how it is different or .

The new closed-as-duplicate banner says:     This question has been asked before and already has an answer. If those answers do not fully address your question, please .   I think it should instead say     This question has been asked before and already has an answer. If answers there do not fully address your question, please  or  to the pre-existing one.   — to discourage re-re-asking the same question. (I also changed "those answers", which has no plural , to "answers there", which doesn't need one.)    As of September 19, 2013, the original text quoted above has returned here.


I'm trying to construct my own expressions evaluator based on the Shunting-yard algorithm. I'm having difficulty adding String objects to the stack I have though. My code just skips over these lines every time, even when the condition is met. Any suggestions? I have the operatorStack declared as:  Stack operatorStack = new Stack();   I'm thinking that it has something to do with my if statement. I've tested it with the Eclipse debugger and when the currentChar variable shows as "(" it still skips over the push to the stack.  Here is the excerpt in question:  int count = 0; String currentChar=new String();  //While loop to test for the conditions stated in the Shunting-yard algorithm. while (count<=temp.length()) {      currentChar = temp.substring(count, count+1);     if(currentChar == "(")         operatorStack.push(currentChar);      if(expressionEval(currentChar) instanceof Integer)         outputQueue.offer((Integer)expressionEval(currentChar));      if(currentChar == "+" ||                 currentChar == "-" ||                 currentChar == "<" ||                 currentChar == "?") {          while(operatorStack.peek() == "+" ||                            operatorStack.peek() == "-" ||                            operatorStack.peek() == "<" ||                            operatorStack.peek() == "?") {             outputQueue.offer((Integer)operatorStack.peek());             operatorStack.pop();         }          operatorStack.push(currentChar);     }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Why doesn't sound wave escape in a open end pipe, why does it reflect again at open end of organ pipe when it can just move outside.

How can standing waves be produced in an open organ pipe even though both of its ends are open? Can someone explain with more clarity?


I have a event type and event organizer.Based on the event type,event organizer will search.All the functions are working properly ,but name is not printing on the screen.Here is the code.
                 Event Organizer User Type 	                 <edu:select name="usertype" fieldlist="<%=userType%>" selvalue='STUDENT' noselect="true" onclick="TypeValue(this)"/>
Student Id<edu:prnStar />
	                  <input type="text" name="eventorganizer" id="eventorganizer" maxlength="25" onblur="validateField('SPLALPHA',this)"/>
   Here are the functions  function TypeValue(as){  ttype=as.value;  if(ttype=="STUDENT"){      document.getElementById('ele').innerHTML="Student Id<edu:prnStar/>";  }else if(ttype=="STAFF"){      document.getElementById('ele').innerHTML="Staff Id<edu:prnStar/>";  }else{      document.getElementById('ele').innerHTML="Guest/Visitor Id<edu:prnStar/>"; }  document.edufrm.typee.value=ttype;   }  //For Dynamic Staff Search  function openwindow1() {      window.open('EduManage.jsp?control=search1&searchno=5_0s1&position=2','','width=790,height=420,left=0,top=70,scrollbars=1,location=no,status=no,resizable=yes'); }  //For Dynamic Student Search  function openwindow2() {     window.open('EduManage.jsp?control=search1&searchno=3_0s1&position=2','','width=790,height=420,left=0,top=70,scrollbars=1,location=no,status=no,resizable=yes'); }   Can anyone help?


Given that $a^2 + b^2 + c^2 = 1$ How can I prove that the maximum value of |a - b| + |b - c| + |c - a| is $2\sqrt{2}$ ? In extends, given that $a_1^2 + a_2^2 + a_3^2 + ... + a_{2020}^2 = 1$ find the maximum value of $|a_1 - a_2| + |a_2 - a_3| +|a_3 - a_4| + ... + |a_{2020} - a_1|$

Given reals $a_1, a_2, \cdots, a_{n - 1}, a_n$ such that $a_1^2 + a_2^2 + \cdots + a_{n - 1}^2 + a_n^2 = 1$ $(n \in \mathbb N, n \ge 3)$. Calculate the maximum value of $$\large |a_1 - a_2| + |a_2 - a_3| + \cdots + |a_{n - 1} - a_n| + |a_n - a_1|$$   There must exist $1 < k < n$ such that $a_{k - 1} \le a_k \le a_{k + 1}$  $ \implies |a_{k + 1} - a_k| + |a_k - a_{k + 1}| = |a_{k + 1} - a_{k + 1}|$.  Repeat the above process for about $n - 1$ times and we have that $$|a_1 - a_2| + |a_2 - a_3| + \cdots + |a_{n - 1} - a_n| + |a_n - a_1| \le 2 \cdot \min(|a_i - a_j|, 1 \le i < j \le n)$$  Now we just have to find the maximum value of $\min(|a_i - a_j|, 1 \le i < j \le n)$ for $$a_1^2 + a_2^2 + \cdots + a_{n - 1}^2 + a_n^2 = 1$$, which I don't know how.


This came out of  when discussing in the comments what is and is not allowed. For some context, David Coffron said in the comments of the above question:  [...] Does unofficial, published content (i.e. 3rd party content) count for your question? [...] [... I answered with basically "what even is XGtE Expanded Racial Feats?" ...] [...] It does have WoTC approval (according to the document itself), but I don't think its considered official. Bit of a weird case. XGtE is an official book, but the expanded feats are not MWICT.  So, does the XGtE Expanded Racial Feats have WotC's approval, is it considered official or unofficial, 3rd party or what? What is it exactly?

(Dungeon Masters Guild) is a Wizards of the Coast-sponsored platform that holds an immense amount of material provided by the community and WoTC themselves. It seems to contain a mix of homebrew and officially published and AL-usable materials.  How do you determine how something on DMsGuild is classified in terms of being  at the same level as PHB, MM, etc., or if it's homebrew, or something in between?  I'm not looking for personal opinions on classification, but on if/how WoTC has classified the materials published on the platform.


It would be great to be able to have mini-Stack Exchange sites for each course that I'm taking in university.  At the moment we're using Piazaa or some generic forum. But having a Stack-Overflow like page for each class would make Q & A much more effective.  This would require people to be able to create temporal Stack Exchange sites, like:  www.university.stackexchange.com/UniversityOfToronto/CSC458  etc..  Thoughts?

So at my university (Aberystwyth) we all seem to have Q&A groups on Facebook for all the various courses and disciplines. Alongside societies, websites and all the rest.  I think it would be fantastic if universities could own their own set of Stack Exchange sites, setting up a separate exchange for each discipline. If this is done correctly it provides an education in Stack Exchange etiquette and removes (hopefully!) the vast majority of homework questions that seem to flood at the very least, Stack Overflow.  The best part about this is that it gives courses a great way to communicate their help on what I find the best platform ever for any kind of help. Of course it would require the universities (or at least institutes) to get behind this, as well as the lecturers and hopefully the alumni too.  What do you guys think of the idea? An overall yae or nae on the core of it?  I'm not flat out suggesting this is something that should be done, I'm wondering if it's: a) Something that should be done b) Something that would work well for both the universities & the Stack Exchange communities  What are your opinions?


I have the newest version of iOS 11 on an iPhone SE. I am having no luck figuring our what time text messages were sent or received. Is there any way to do this?

In iOS 7, I've noticed that some SMS/MMS messages have a date and time stamp displayed above the message.  Although this is useful, not all text's in the list receive such a date and time stamp.  Is there a way that I can view the date and time for ever text message?


I had a problem while writing emails where I want to tell few things in order. I had used "Firstly" in the email but I am not very sure is it a correct way to talk or write.

I've come across many sources claiming that the words firstly and first (as an adverb) can be used interchangeably. They, however, only seemed to be comparing their meanings with regard to enumerations - first(ly) I want to say ..., second(ly) ..., last(ly) ...  What bothers me more is if the word firstly is also usable within the meaning of at first or initially like in the sentence:     Muons (subatomic particles) were firstly observed in cosmic rays.   The word first fits there very well, but is that the case for firstly too? I have not found a dictionary definition or example saying so.


The first script is very long, and I need to use only the top of it:  using System; using System.Collections; using System.Collections.Generic; using UnityEngine;  public class mBitmap2MeshV30a : MonoBehaviour {     public Texture2D SourceTexture;      private float Pixel_vs_Unit_Scale = 1;       public float extrudeDepth = 1;      private Vector2 scanpoint;     private bool gotStart = false;     private int maxsteps = 512;      public bool invertFaces = false;     private Mesh srcMesh;     private mMeshExtrusion2.Edge[] precomputedEdges;     private List<ExtrudedTrailSectionBM3> sections;      public class ExtrudedTrailSectionBM3     {         public Vector3 point;         public Matrix4x4 matrix;         public float time;     }   I need to assign a value to SourceTexture from another script. This is the other script:  void Start () {     text2d = new Texture2D(10, 10, TextureFormat.ARGB32, false);     System.Drawing.Font myf = new System.Drawing.Font(FontFamily.GenericSerif, 12);     Image myimage =  DrawText("Hello", myf, System.Drawing.Color.Red, System.Drawing.Color.Black);     Bitmap mybitmap = new Bitmap(myimage);      MemoryStream msFinger = new MemoryStream();     mybitmap.Save(msFinger, mybitmap.RawFormat);      text2d.LoadImage(msFinger.ToArray());     filter.GetComponent<Renderer>().material.mainTexture = text2d;      mBitmap2MeshV30a bb = new mBitmap2MeshV30a();     bb.SourceTexture = text2d; }   The problem is I can't make a new mBitmap2MeshV30a bb = new mBitmap2MeshV30a();. Both scripts are attached to the same GameObject, in the hierarchy.

I need to access a variable from another script in Unity, but I can't figure it out. Script:  public class move : MonoBehaviour { public float speed; // Use this for initialization void Start () {  }  // Update is called once per frame void Update () {     transform.position += Vector3.left * Time.deltaTime * speed; }  }   I want to access the variable speed in another script, but I can't. Any help will be appreciated :)


Do I need to place a comma before 'and'? 'Trelawny buys a schooner(,)and, with the help of Long John Silver, he puts together a crew.'

After showing me the house, Nana led us to the living room, and with Mongai's Take Me Somewhere Nice playing on in the background, we started on the Scotch we'd bought at the 7-Eleven. The dim light and the soft   Is the comma correctly positioned before the italics in the example above? Or I should place the comma after and?


A study that was carried on recently showed that even babies at the age of few months know that $1+1=2$. My question is : is this a fact that can be proved, or is it a just a postulate as those in geometry ?   Also what about the saying "A given statement can be either true or false." ? Why are there two and only two cases for a statement ?

Me and my friend were arguing over this "fact" that we all know and hold dear. However, I do know that $1+1=2$ is an axiom. That is why I beg to differ. Neither of us have the required mathematical knowledge to convince each other. And that is why, we decided to turn to Math Stackexchange for help. What would be stack's opinion?


I've read a lot of posts and everyone says, that virtual table is per class, not per object and object only has _vtpr pointer to shared vtable. But please consider this example:  class Base { public:     virtual void func1(void) {}     virtual void func2(void) {} private:     int dummy; };  class Der1 : public Base { public:     virtual void func1(void) {} private:     int dummy; };  class Der2 : public Base { public:     virtual void func2(void) {} private:     int dummy; };  int main(void) {     Base * obj1 = new Der1;     Base * obj2 = new Der2; }   Does obj1 and obj2 relates to that one unique Base class vtable? I believe the answer is no, but can you please explain? And if both of these objects do relate to the same vtable, how it is determined which methods to be called? For example, obj1->func1 reference is different than obj2->func1.  UPDATE: What operations are executed when doing Base * obj1 = new Der1;? Can someone write a pseudo code for these actions?

Does every object of virtual class have a pointer to vtable?  Or only the object of base class with virtual function has it?  Where did the vtable stored? code section or data section of process?


I tried to install apache2 with  sudo apt-get install apache2   Why am i seeing this   E: Type 'gpg' is not known on line 1 in source list /etc/apt/sources.list.d/sublime-text.list E: Type 'gpg' is not known on line 1 in source list /etc/apt/sources.list.d/sublime-text.list

Every once in a while I see users having issues to update due to errors like this:  E:Type 'ain' is not known on line 1 in source list /etc/apt/sources.list.d/some-ppa.list'   with varying types/line numbers/source list files (often after removing a PPA).  How can such an error be fixed?


I've added a repo with the following:  add-apt-repository "deb http://archive.ubuntu.com/ubuntu artful universe"   How would I remove it? I'm using this in a automated script also!

I've added many PPAs using the add-apt-repository command. Is there a simple way to remove these PPAs? I've checked in /etc/apt/sources.list for the appropriate deb lines but they aren't there.   This is on a server system so a command line solution would be great!


Following are the text samples I have:  text1 : "The salary is $34-$36"  text2 : "The salary is $34.50-$36.20" text3 : "The salary is $45000-$34000" text4 : "The salary is $45-$34K"  So whenever I find patterns like $34-$36 or $34.50-$36.20 I need to add word hour to the text and whenever I find patterns like $45000-$34000 or $45-$34K I need to add word salary to text.   Can someone help me how to solve this in R using regular expressions?  Thank-you.

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


What version of Ubuntu would be good for a HP 1110nr mini netbook 1g memory 160g processor.

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


echo $HOME $var /home/user abc   My variables.  echo $HOME$var | sed "s/$(echo $HOME$var | cut -c 3)/ello/g" /hellome/userabc   This works as expected.  echo $HOME$var | sed "s/$(echo $HOME$var | cut -c 3-)/ello/g" sed: -e expression #1, char 16: unknown option to `s'   Adding the range "3 to the end" produces failure. The subexpression has no problem when isolated.

Take the following script:  #!/bin/sh sed 's/(127\.0\.1\.1)\s/\1/' [some file]   If I try to run this in sh (dash here), it'll fail because of the parentheses, which need to be escaped. But I don't need to escape the backslashes themselves (between the octets, or in the \s or \1). What's the rule here? What about when I need to use {...} or [...]? Is there a list of what I do and don't need to escape?


Evaluate the line integral $\int_{C}^{ }xe^{y}ds$, where $C$ is the line segment from $(-1,2)$ to $(1,1)$.    I know that I need to first get a parametrized equation. I got $r(t) = [(2t - 1), (-t + 1)]$. I am not sure how to proceed.

Evaluate the line integral  $$\int_C xe^{y}\, {\rm d}s,$$  where $C$ is the line segment from $(-1,2)$ to $(1,1)$.  I do not get this part of calculus at all please show me how this is solved and if you give me hints is ok too. Please help me. Thanks


I am new to JS. I have the following question -  Is it right to say that I can declare variables only in global scope or inside a function/method only in JS and in no other type of Object which is not function/method?  I understand that properties can be defined in any object of Javascript but variables cannot be declared everywhere.    EDIT: I might not have right terminology to explain but in simplest words I need a list of places where i can write var x = .. in JS code. Please,I am not looking for scope of a variable.

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


First of all i am not looking for very accurate lower bound. It would be enough to me the following :      Prove that $TREE(3)>f_{\omega +2}(3)$ (here that function $f$ comes from fast growing hierarchy)   Generally i don't know how to solve it. I have a little idea. It is to show that there is a injective function between two sets. One of them would be the set of elements of the longest sequence with 3. labels second set would have cardinality equal or greater to the $f_{\omega +2}(3)$. But i don't know how to find that function

I'm interested in where TREE(n) would rank on the fast growing hierarchy. I've read that the small tree(n) function is bound by the Small Veblen Ordinal. Given that TREE(n) grows faster, where would TREE(n) fall in the FGH?   Assuming Friedman's definition of TREE(n):  TREE(n) is the length of the longest sequence of trees T1,T2, … labeled from {1,2,3,..,n} such that, for all i, Ti has at most i vertices, and for all i, j such that $i<j$, there is no label-preserving homeomorphic embedding from Ti into Tj.


I am making an A0 poster using the lmodern package, which has a strange influence on formula formatting.  Removing this package makes everything work well, but I would like to know what I have done wrong.  With lmodern package :    Without lmodern package :    Here is the corresponding code.  \documentclass[landscape,30pt]{sciposter} \usepackage{amsmath,amssymb,amsrefs} \usepackage[english]{babel} \usepackage{lmodern}   \begin{document}  $$\int_0^\infty \sqrt{\frac{f(t)}{g(t)}}dt$$  \end{document}

Both the  package and the  package define the delimiter macros \big, \Big, \bigg and \Bigg based on the internal macro \bBigg@. However, as the following minimal example reveals the amsmath and exscale versions of \bBigg@ have a different meaning:  \documentclass{article}  \usepackage{etoolbox}  \usepackage{lmodern}  \usepackage{amsmath}  \show\big %% > \big=\long macro: %% ->\bBigg@ \@ne .  \csshow{bBigg@} %% > \bBigg@=macro: %% #1#2->{\@mathmeasure \z@ {\nulldelimiterspace \z@ }{\left #2\vcenter to#1\big@size {}\right .}\box \z@ }.  \usepackage{exscale}  \show\big %% > \big=macro: %% ->\bBigg@ \@ne .  \csshow{bBigg@} %% > \bBigg@=macro: %% #1#2->{\hbox {$\left #2\vcenter to#1\big@size {}\right .\n@space $}}.  \begin{document}  \noindent \Huge \(\big(\sum_{i=1}^{N}i\big)\)  \end{document}   Does this mean that I might get different results, depending on whether the amsmath package is loaded before or after the exscale package? Or are the two versions of \bBigg@ interchangeable so that the package loading order essentially doesn’t matter?


I'm trying to write a code that returns a new array which swaps every pair of elements. If there is an odd number of elements, the last element remains the same.   Currently what I have is this which doesn't seem to be working at all. I keep returning a nullpointerexception error when trying to test it   public static String[] pairSwap(String[] inputArray) {     String[] outputArray = new String[inputArray.length];     for (int i = 0; i < inputArray.length; i += 2) {          inputArray[i] = outputArray[i + 1];         inputArray[i + 1] = outputArray[i];          if (inputArray.length % 2 != 0) {             inputArray[inputArray.length] = outputArray[inputArray.length];         }     }     return outputArray; }

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


I'm applying to Computer Science PhD programs (subarea is Theory). Due to Covid, I think there are roughly 4 types of schools in terms of GRE General requirements:  Don't even send your score (they will be ignored) Optional (sometimes accompanied with "we expect most students won't have a GRE score" or "we perform a holistic review and you won't be at a disadvantage if you don't send") Not required but (encouraged)/(can help if application has weak sides) Required  My question is about the 2nd and the 3rd type. How do I decide if I should send them my scores for each type? Unfortunately they don't generally publish the average GRE scores either (some do). More specifically, my case is as follows. I'm applying to top 20 CS schools in the US, and I am an international student from a not-famous country and school. My GRE score is Quantitative:170/170 (96%), Verbal:161/170 (88%) and Analytical Writing: 5.0/6.0 (92%). If it matters, I'm particulary concerned about my verbal score and my GPA is 3.9+, my TOEFL score is strong (110+). Since I can't know if people generally took the GRE or not or if they're sending their scores, I can't decide whether to send. Would my score help me, hurt me or simply not affect me?

I am preparing to submit applications to high ranking CS PhD programs in the US. My GRE quant score is not quite what I wanted (162V/163Q). I have strong research experience, good letters from professors I worked with, and a decent GPA (~3.6) from a top 10 undergrad CS school. However, my quant score is only around 80th percentile, whereas many top CS programs have averages in the 90-95 range. I'm not sure if submitting my GRE scores will hinder my chance, or if the opposite case is true. Is it the case that a student without GRE scores will look lazy, or look like their hiding poor scores? All of the institutions that I am applying to have made the GRE optional.


Can't find information on it, since don't know what it is actually. This is what I have in Rendered Viewport Shading:    And this is what Render shows me as an result:    So, what are these vertical lines? Seems like something wrong with UV, but why then Viewport shows everything ok? I mean, I'm pretty noob in blender, so I don't have any idea.

I was following  on creating a watch and noticed that when I rendered the watch, some pieces were messed up.  I'm new to 3D modeling and I've just learned Blender, I can't explain it well, so here's a picture:    Other examples:     I don't know if it's a problem with my World texture, the object, or the object's texture/material, so I can't even guess how to fix it. What causes this? Is it possible to fix it?


I've been trying to install the Microsoft anti-virus but Microsoft Security Essentials does not work and I can't find Defender to install.  From what I know you CAN NOT use Microsoft Security Essentials with Windows 8/Server 2012. I've done some searching for Windows Defender Download but I can't fine a link anywhere. How can I get this installed?

On earlier versions of Windows client and server you could install Microsoft Security Essentials, free antivirus from Microsoft. In Windows 8 client, it is integrated into Windows Defender. However, I see no such option in Windows Server 2012 and attempts to install MSE fail.


This question might be silly, it's easy to look at and could've been answered after looking at the Internet, but still, I came here for  help. This question look like this:  I want to create a table using LaTeX. The table looks like this:    I was able to manage make a table, but it is not what I envisioned. It looks like this:    The code I used looks like this:  \documentclass[a4paper,twocolumn]{article} \usepackage[margin=1in]{geometry} \usepackage{multirow,booktabs} \setlength\parindent{0pt} \begin{document}  \begin{tabular}{|c|c|c|c|} \hline \multirow{2}{*}{USERNAME} & \multirow{2}{*}{PASSWORD} & Did the user denied access to the app when the user inputted wrong username or password? \\                           &                          &  YES                    & NO \\                     \hline papad@gmail.com          & 7221456                  &                         & \\                       \hline idislikeyou@gmail.com    & password                 &                         &  \\                      \hline devs@gmail.com           & 12A2ZAQR                 &                         & \\                      \hline devs@gmail.com           & password                 &                         & \\                      \hline  \end{tabular}  \end{document}   My question is:      How can we make a table using LaTeX that looks like the first picture above?   And I wonder what is the best book for LaTeX to be read...

I have this table, but wanted to format the first row. I like to match the two columns of first row, and last two columns of the same first row. Any suggestion on how to do that?  \begin{table}[!h]  \caption{Comparison of percentages.} \begin{tabular}{lclclclclc} \hline \hline  Mode &  Var  &  Cum\\ \hline {}       & EF   & CHF    & EF2   & CHF2\\ 1   &  17.5 & 19.1   & 17.5  & 19.1\\ 2   &  11.8 & 12.7   & 29.3  &  31.9\\ 3   &  6.6  &  5.6         & 35.9    &  37.4\\ \hline \end{tabular} \end{table}


I have a problem with the Difference-In-Differences' control group.  In particular I have data from 2001 to 2015 and the problem rises because the timings of the treatment period can start from 2006 (till 2015) but is different for the different treatment group's elements. In this case the dummy variable that represent the treatment period can vary in the treatment group (in my case, it will be 1 for each firm (i) that does IFRS reporting in year (t), but what happens to the same time variable for the control group? I don't think that it could be right if the time variable will always be zero for the control group, but I could be wrong... so, should the time variable (for the control group) be 1 from 2006 to 2015 (the represent the period when the treatment starts, even if not for the whole treatment group?  Please help me and thank you.

When I estimate a difference in differences model with two time periods, the equivalent regression model would be  a.  $Y_{ist} = \alpha +\gamma_s*Treatment + \lambda d_t + \delta*(Treatment*d_t)+ \epsilon_{ist}$   where $Treatment$ is a dummy which is equal to 1 if the observation is from the treatment group and  $d$ is a dummy which is equal to 1 in the time period after the treatment occured   Thus the equation takes the following values.   Control group, before treatment: $\alpha$ Control group, after treatment: $\alpha +\lambda$ Treatment group, before treatment: $\alpha +\gamma$ Treatment group, after treatment:  $\alpha+ \gamma+ \lambda+ \delta$   Hence, in a two period model the difference in differences estimate is $\delta$.  But what happens concerning $d_t$ if I have more than one pre and post treatment period? Do I still use a dummy that indicates whether a year is before or after the treatment?  Or do I add year dummies instead without specifying whether each year belong to the pre or post treatment period? Like this:  b. $Y_{ist} = \alpha +\gamma_s*Treatment + yeardummy +     \delta*(Treatment*d_t)+ \epsilon_{ist}$  Or can I include both (i.e $yeardummy +\lambda d_t$)?  c. $Y_{ist} = \alpha +\gamma_s*Treatment  + yeardummy + \lambda d_t +     \delta*(Treatment*d_t)+ \epsilon_{ist}$  In conclusion, how do I specify a difference in differences model with multiple time periods (a,b or c)?


Consider the set of matrices G = {[1, a, b; 0, 1, c; 0, 0, 1] : a, b, c belong to Q (set of rational numbers)} Given that matrix multiplication is associative, find the center of G.  Since we know that the center of a group, Z(G) = {a belong to G: ax=xa for all x belong to G} Hence Z(G) = {0, 1, a, b, c} for all a, b, c belong to Q  Is it correct?

Let $H(F)$ be the Heisenberg group over the field $F$ introduced in Exercise 11 of Section 1.4. Determine which matrices lie in the center of $H(F)$ and prove that $Z(H(F))$ is isomorphic to the additive group $F$.   Section 1.4 defines the Heisenberg group $H(F)$ over the field $F$ to be the group of all upper-unitriangular $3\times 3$-matrices $\begin{pmatrix} 1 & a & b \\ 0 & 1 & c \\ 0 & 0 & 1 \end{pmatrix}$ with entries in $F$.  When I worked out the elements in the center, I got its elements such that the diagonal was multiplied by a scalar and the element in the first row,third column possibly non-zero. So, you see that my problem was compounded as I just did not see how the center was isomorphic to only F.  Thanks for any help that I might receive.


Supposed I have a list of $n$ real numbers, where $n$ is odd. The list is constructed such that I can remove any arbitrary number from the list, and the remaining numbers can be partitioned into two equal-sized subsets with equal sums. Prove that all numbers in the list are equal.   This should be somehow related to linear algebra. A way I could think of to interpret this is that the list is essentially a $1 \times n$ row, and there exist $n$ $n \times 1$ vectors with one zero in some entry and $1$'s and $-1$'s in other entries with the entries summing to $0$, such that the product of the row and the column vector is $[0]$.  In other words, the entries/$1 \times 1$ columns in the row are linearly dependent once we remove any arbitrary entry/column. I'm not sure how this is/could be related to the proof though.  Thanks in advance!

Let $S$ be a finite collection of real numbers (not necessarily distinct). If any element of $S$ is removed then the remaining real numbers can be divided into two collections with same size and same sum ; then is it true that all elements of $S$ are equal ?  (I know the result is true if the "reals" are replaced by "integers".)


It cannot be a Dirac delta as this is not a continuous normalisable function. Further to the answer written by John Rennie  We may assume that the collapse is not perfect. In this case, how is the quantum formalism applied to calculate the probability of this measurement? One solution to this is to discretise the continuous operator as a function of position. The eigenstates are then degenerate and we will have a non zero probability of measurement. However, is it necessarily true that the resulting collapse will be a projection of the wavefunction? Can it not be 'reset' to a simpler distribution, for example Gaussian?

Text books say that when you measure a particle's position, its wave function collapses to one eigenstate, which is a delta function at that location. I'm confused here.   A measurement always have limited accuracy. Does the wave function collapse to exactly a eigenstate no matter what accuracy I have? When a particle is in an eigenstate of position, I can represent the state in momentum basis, and calculate it's expected value (average) of kinetic energy. This gives me infinity. Can a particle ever be in such a state?


i have a hard disc that is completely dead. dead in the sense the hard disc is not even detecting in computer or neither starting. i had data in that hard disc which is important. How can i take retrieve the data from that drive?

I am using Acer Laptop one day before my Hard Disk is not detected in BIOS and not booting it's shows Insert Boot Disk and I am try another H.D.D it's boot perfectly in my Laptop but,I want detect and recover my data on not detected hard disk. I am not experience about Hard Disk please, can any one help me how to recover my data from not detected Hard Disk.


I am testing polymorphism in C# with generic types and trying to find the way to make generics countable but C# compiler does not accept operation such as summation on generic types. I found one of the workarounds based on which I created the code below that inherits from an interface that provides a proper function:  using System.IO; using System;  interface ICountable<T> {     T Add(T a, T b);     T Multiply(T a, T b); }  interface IExecute<T> : ICountable<T> {     T Operation(T a, T b); }  class IntSum : IExecute<int> {     public int Add(int a, int b)     {         return a + b;     }     public int Multiply(int a, int b)     {         return a*b;     }     public int Operation(int a, int b)     {         return Add(a,b);     } } class DoubleMultiply : IExecute<double> {     public double Add(double a, double b)     {         return a + b;     }     public double Multiply(double a, double b)     {         return a*b;     }     public double Operation(double a, double b)     {         return Multiply(a,b);     } }  class Program {     static void Main()     {         Console.WriteLine(DoOperation(new IntSum(), 1, 2));         Console.WriteLine(DoOperation(new DoubleMultiply(), 3.5d, 3d));     }      static TResult DoOperation<TOperand, TResult>(TOperand obj, TResult a, TResult b)     where TOperand : IExecute<TResult>     {         return obj.Operation(a,b);     } }   The code above works but in the end I use inheriting to a concrete primitive types and there's a lot of redundant code blocks. My ultimate goal would be to make such types as much generic as possible, something similar to this:  using System.IO; using System;  interface ICountable<T> {     T Add(T a, T b);     T Multiply(T a, T b); }  interface IExecute<T> : ICountable<T> {     T Operation(T a, T b); }  // Generic code class Sum<T> : IExecute<T>, ICountable<T> {     public T Add(T a, T b)     {         return a + b;     }     public T Multiply(T a, T b)     {         return a*b;     }     public T Operation(T a, T b)     {         return Add(a,b);     } }  class Program {     static void Main()     {         //Console.WriteLine(DoOperation(new IntSum(), 1, 2));         //Console.WriteLine(DoOperation(new DoubleMultiply(), 3.5d, 3d));     }      //static TResult DoOperation<TOperand, TResult>(TOperand obj, TResult a, TResult b)     //where TOperand : IExecute<TResult>     //{     //    return obj.Operation(a,b);     //} }   Obviously, the compiler complains as it cannot sum two generic types. Do you think I always have to inherit to specific primitive? Thanks.

What would I do if I want to have a generic method that only accepts types that have overloaded an operator, for instance the subtraction operator. I tried using an interface as a constraint but interfaces can't have operator overloading.   What is the best way to achieve this?


I'm having a hard time finding when I left a subgroup out.  For example, lets take $G=\mathbb{Z}_2 \times  \mathbb{Z}_4.$  Subgroups:  $s_1:$$\langle(0,0)\rangle$  $s_2:$$\langle(0,1)\rangle=\{(0,0),(0,1),(0,2),(0,3)\}$  $s_3:$$\langle(0,2)\rangle=\{(0,0),(0,2)\}$  $s_4:$$\langle(0,3)\rangle=\{(0,0),(0,3),(0,2),(0,1)\}=s_2$  $s_5:$$\langle(1,0)\rangle=\{(0,0),(1,0)\}$  $s_6:$$\langle(1,1)\rangle=\{(0,0),(1,1),(0,2),(1,3)\}$  $s_7:$$\langle(1,2)\rangle=\{(0,0),(1,2)\}$  $s_8:$$\langle(1,3)\rangle=\{(0,0),(1,3),(0,2),(1,1)\}=s_6$  By looking at this I'd say all the subgroups are here, but for this $G$ there is also the subgroup $\mathbb{Z}_2 \times  2\mathbb{Z}_4$. How should I know that?  If I take some other examples like $\mathbb{Z}_3 \times  \mathbb{Z}_4$ or $ \mathbb{Z}_3 \times  \mathbb{Z}_3$, the type of "list" I made is enough to determinate all the subgroups.

I am wondering how do we find all subgroups of a direct product? Is there a method to find it?  For example, how can we find all the subgroups of $\mathbb{Z}_2\times\mathbb{Z}_2$?  There is the answer: $\{(0, 0), (1, 0)\}, \{(0, 0), (0, 1)\}, \{(0, 0), (1, 1)\}$, and the improper and trivial subgroup. But I do not know the method how to find it.   All I can think about is the following: since the order of $\mathbb{Z}_2\times\mathbb{Z}_2$ is $4$, the order of a subgroup of it can be $1,2$ or $4$.   If order is $1$, then it is trivial, and if order is $4$, it is proper. Then, the order of a subgroup is $2$. We know all the elements of   $\mathbb{Z}_2\times\mathbb{Z}_2$, so we try all the pairs.   Is that the method?   But what if we are given a bigger order product, such as $\mathbb{Z}_2\times\mathbb{Z}_8\times\mathbb{Z}_3\times\mathbb{Z}_9$? It looks very long to try all possibilities.   Can anyone help?  Thanks


What is a difference between a friend of mine and my friend? Both are equally fine at any settings? Can this lead to any confusion or misunderstanding?  This question is different from how to use apostrophe s or of. As these two are quite common expressions in spoken English, the difference is beyond the range of how to use possessive forms.

Sometimes when I write, for example, "the boundaries of segments", I am suggested to use "segments' boundaries" or even "segment boundaries".   Or "the page's content" vs. "the content of the page" vs. "the page content". Then I would like to know is it always preferred to use phrases with apostrophe or adjective?  For example      In our terms, they are mainly textual elements within the page content, which serve as the starting point  of a data region (or a data region's starting point ?)  or a distinctive feature within it


I have seen several instances of this over the last week and wanted to get a viewpoint from the higher-ups.  This question addresses the corollary to this    Please consider the following prototypical (context free) thread...  Question Title:  How to make my doodlies fit? Text:  I can't make all my doodlies fit, can anyone help?  Answer: Move some of them over there. Comment:  WOW! that really worked!  But now I have humpers            on the carumpers!  How to fix that?   In essence, the person got 'unstuck' and proceeded with his project only to encounter the next problem that appeared on his awareness horizon.  And this is sometimes in a completely new area all together, hence the 'Russian Doll' metaphor.  I have left indicative commentary, but this seems to be ineffective.  Flag?  D/v?  Retag?  Edit the question?

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


I have this code that is supposed to avoid modifying the original data object "info" array of objects but it does! despite it is processing copies of this array?! I need to keep the original data object intact as otherwise, I am getting continually modified data object with each call of the functions as if they are chained together?!     const data = {     owner: "John Doe",     info: [       {         employeeId: 123000456,         firstName: "Alex",         lastName: "Mckenna",         email: "alex@work.org",         salary: 48000,         department: "Art and Media",       },       {         employeeId: 123000777,         firstName: "Devon",         lastName: "Foley",         email: "devon@work.org",         salary: 75000,         department: "Advertising",       },       {         employeeId: 123000894,         firstName: "Riley",         lastName: "Couch",         email: "riley@work.org",         salary: 33000,         department: "Shipping",       },       {         employeeId: 123000533,         firstName: "Cara",         lastName: "Eramchuk",         email: "cara@work.org",         salary: 39000,         department: "Accounting",       },       {         employeeId: 123000721,         firstName: "Cole",         lastName: "Tilbury",         email: "cole@work.org",         salary: 43000,         department: "Accounting",       },       {         employeeId: 123000832,         firstName: "Bree",         lastName: "Northam",         email: "bree@work.org",         salary: 61000,         department: "Shipping",       },       {         employeeId: 123000271,         firstName: "Mark",         lastName: "Miller",         email: "mark@work.org",         salary: 55000,         department: "Sales",       },       {         employeeId: 123000442,         firstName: "Jenna",         lastName: "McEvoy",         email: "jenna@work.org",         salary: 40000,         department: "Sales",       },     ],   };     const myCompany = {   renameProp(arr, old, neu) {     const modified = arr.map((obj) => {       if (old in obj) {         obj[neu] = obj[old];         delete obj[old];         return obj;       } else {         return `property, ${old}, doesn't exist for employee ${obj["firstName"]} ${obj["lastName"]}`;       }     });     return modified;   },   sortCopy(arr, prop) {     try {       const copied = Array.from(arr);       copied.sort((a, b) => {         if (typeof a[prop] === "string" && typeof b[prop] === "string") {           if (a[prop].toLowerCase() > b[prop].toLowerCase()) return 1;           else if (b[prop].toLowerCase() > a[prop].toLowerCase()) return -1;           else return 0;         } else {           if (a[prop] > b[prop]) return 1;           else if (b[prop] > a[prop]) return -1;           else return 0;         }       });       return copied;     } catch (err) {       return err.message;     }   }, };  console.log(myCompany.renameProp(data.info, "salary", "wage")); console.log("\n\n", myCompany.renameProp(data.info, "firstName", "name"));  console.log("\n", "examples of second function: ", "\n");  console.log(   "sorted by employeeId: \n\n",   myCompany.sortCopy(data.info, "employeeId") ); console.log(   "\n sorted by first name: \n\n",   myCompany.sortCopy(data.info, "firstName") );  console.log("\n\n original array \n\n", data);

What is the difference between a deep copy and a shallow copy?


My test circuit is shown below.  I've tried various configurations but keep getting jumps in the output counts.  Seems to be repeatable and consistent.  For instance, the first jump always occurs around 7k-8k counts.  I saw another post where the problem seemed to be with power supply filtering.  I've tried many different filtering caps on my regulator output, the register clock signal and the counting clock signal.  Advice would be greatly appreciated at this point.    Arduino code can be reviewed    Arduino Output:    UPDATE   Scope trace for RCLK input:   Scope trace for CLKA input:   5V supply with 555 running:   5V supply without 555 running:   UPDATE  Tried replacing the counter chip with a new one and got the same result as before.  Also, when I slowed down the input signal to 10 Hz I was able to see that the first jump occurred between decimal 8114 and 8150.  The first decimal value after the jump was 16390, almost exactly double!  00011111 10110010   Decimal: 8114 <-- Count before fault  00011111 11100100   Decimal: 8164  <-- Expected Count after fault  01000000 00000110   Decimal: 16390  <-- Actual Count

I am using a "Dual 16-bit binary counter with 3-state output registers" (SN74LV8154) to count input pulses up to 32 bits.  It is working fine most of the time, but some of the bits in the counter seem to flip randomly. The result is reflected in the register, as I see the output value sometimes jump forward and/or backward.   Jumps are persistent (not punctual misreadings) since the value does not jump the other way around right after the issue. e.g.    0x12fe 0x12ff 0x1200 (should be 0x1300) 0x1201 0x1202 (0x0100 still not on)   The chip allows to read byte by byte with the help of a 4 bit word selector. This is done quite frequently, word by word, and I record a timeseries with the result. I expect the counter to go up by a few increments between reads.  The result is fine most of the time, but it looks like some internal carries are either forgotten or doubled.  Here are a few examples:  |----------------------+------------------------+-------------| | Before               | After                  | Jump        | |                      | (Expected)             |             | |----------------------+------------------------+-------------| | 0b010011000011111111 |  0b010011001000000000  | 0b100000000 | |                      | (0b010011000100000000) |             | | 0b110001000001111111 |  0b110001000000000000  | -0b10000000 | |                      | (0b110001000010000000) |             | | 0b111100101011111111 |  0b111100110000000000  | 0b100000000 | |                      | (0b111100101100000000) |             | |----------------------+------------------------+-------------|   I also saw jumps by +/- 16, +/- 32, +/-65536, so I guess the issue is not related to the word size.   Any help on how to investigate this would be much appreciated.  Julien


I have a flashdisk drive that can't mount or backup, but when I check with lsusb that flashdisk is detected:  ➜  ~ lsusb         Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 004: ID 0930:6544 Toshiba Corp. TransMemory-Mini / Kingston DataTraveler 2.0 Stick (2GB) Bus 001 Device 003: ID 1bcf:2c18 Sunplus Innovation Technology Inc.  Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   But, if it is detected then  why doesn't my flashdisk exist in /dev/sdb? Does anyone know what happened to my flashdisk?   ➜  ~ sudo fdisk -l Disk /dev/sda: 465,8 GiB, 500107862016 bytes, 976773168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: dos Disk identifier: 0x00094cd3  Device     Boot     Start       End   Sectors   Size Id Type /dev/sda1  *         2048 195311615 195309568  93,1G 83 Linux /dev/sda2       195313662 199311359   3997698   1,9G  5 Extended /dev/sda3       199313408 942567423 743254016 354,4G 83 Linux /dev/sda4       942569472 976773167  34203696  16,3G 83 Linux /dev/sda5       195313664 199311359   3997696   1,9G 82 Linux swap / Solaris  Partition 2 does not start on physical sector boundary. Partition table entries are not in disk order.  ➜  ~ sudo parted -l Model: ATA WDC WD5000LPVT-2 (scsi) Disk /dev/sda: 500GB Sector size (logical/physical): 512B/4096B Partition Table: msdos Disk Flags:   Number  Start   End    Size    Type      File system     Flags  1      1049kB  100GB  100GB   primary   ext4            boot  2      100GB   102GB  2047MB  extended  5      100GB   102GB  2047MB  logical   linux-swap(v1)  3      102GB   483GB  381GB   primary   ext4  4      483GB   500GB  17,5GB  primary   ext4  ➜  ~ lsblk NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 465,8G  0 disk  ├─sda1   8:1    0  93,1G  0 part / ├─sda2   8:2    0     1K  0 part  ├─sda3   8:3    0 354,4G  0 part /media/agaust/Data ├─sda4   8:4    0  16,3G  0 part  └─sda5   8:5    0   1,9G  0 part [SWAP] sr0     11:0    1  1024M  0 rom    I also tried to check it via Disks:

I have a MicroSD card in a USB adapter (which plugs into a USB port on my machine, and acts like a USB flash drive). I was using Unetbootin to make this a bootable USB flash drive with Kubuntu. But I needed to cancel while it was working. So I killed the Unetbootin process from the console.  Since then, I can't format the MicroSD or delete the folder that Kubuntu made. I have also tried mkdosfs, with no success. I can't mount the drive anymore either? What can I do to make this drive usable again?  Trying to create a new partition table in GParted, as described in Eliah Kagan's answer, does not work. It fails with the error message "imposible crear tabla de particiones" ("unable to create a partition table").


Several times I have come across about this problem. Solve $\phi(n)=m$ where $m$ is a given natural number. I did some investigation on the solution process, but till now I have not found any general procedure. May be I am wrong or may be my search is still require to go further, but I would like to get the suggestion from the experts around here. Can you please tell  me or at least provide me any link where I can find the general process of solving this types of number theoretical equation? Suppose that $m=12, 13, 15$ are given. How shall I proceed?  Thanks in advance

Let $\phi(n) $ is the numbers of number that are relatively prime to n.   Then, how could we solve the equation $\phi(n) = k, k > 0?$   For example:    $\phi(n) = 8 $  I can use computer program to check all numbers that are relatively prime to $n$, but I think there must be an easier way to approach this problem.    Base on this formula: $$\prod_{i=0}^{k} p_{i}a^{a_i} $$ The only thing I can see is n must not have a prime factor > 9, otherwise $\phi(n) > 8 $. I really don't know where to start :( ? A hint would be greatly appreciated.


I completed Unlikely Valintine and invited Valintine to join me.  Than I did Reunion and followed DogMeat.  Once I got to Fort Hagen Valintine said something along the lines of "You should give DogMeat a rest, he's done enough".   I haven't seen DogMeat since.  Where did he go?  I looked around Sanctuary Hills and didn't see him.    Update: I didn't explicitly assign DogMeat to any of my settlements, he just left.  But I'll check the Gas Station (as recommended in ) and report back.

I recently dismissed Dogmeat in favor of Codsworth, and I'm fairly sure I sent him to Sanctuary Hills. However, I've had a fairly detailed look around the place and I haven't found him yet. Does anyone know where he is?


As the story unfolds, a malicious rumor about Mr. Simon spreads after the principal suspends a school bully for beating up a female classmate whom he thinks has "cooties."

I can never figure out whether I should use who and whom. Most people use who for both colloquially, but some people say this is not correct.  What’s the rule for using who and whom correctly?


I have a django template in which a logged in user can check his/her account balance. The balance is obtained in the django template through a form labelled as 'form0'. Now I want to display this user balance through an alertbox. Given below are the relevant files:  HTML:  {% extends "base.html" %} {% load bootstrap4 %} {% block content %} <form action="/profiles/userLogin/" method="POST">     <button  class="material-icons floating-btnz" name="form0" onClick='showMessage()></button> </form>  <script> function showMessage(){     alert("Your balance is " + balance); } </script> {% endblock %}   views.py:  if request.method=="POST":     if 'form0' in request.POST:         x = employee.objects.get(name = request.user)         y = x.balance         return render(request, 'profiles/userLogin.html', {'balance': y})   models.py:  class employee(models.Model):     name = models.OneToOneField(User, on_delete=models.CASCADE)     id = models.CharField(max_length=20, primary_key=True)     balance = models.IntegerField(default=0)   How can I implement this requirement in my system? Any help is appreciated.

When I render a page using the Django template renderer, I can pass in a dictionary variable containing various values to manipulate them in the page using {{ myVar }}.  Is there a way to access the same variable in Javascript (perhaps using the DOM, I don't know how Django makes the variables accessible)? I want to be able to lookup details using an AJAX lookup based on the values contained in the variables passed in.


As the title says, is it possible? What is AOSP (Android Open Source Project)? I want to install a pure Android operating system, nothing else. Full control (root access), no bloatware and all.   Is there any possible way, as Android is said to be an open source, so why we are bounded by these restrictions?

So I have an old unlocked phone and I'd like to load up my own OS.  I've seen some mods out there.  CyanogenMod seems to be the most popular.  However, I was curious if I could just install a pure untouched version of the OS -- as distributed by Google. I seem to remember being able to download a clean compiled version of the Android OS.    Does Google distribute any binaries like this, and if not, is there someone out there that does?    Additionally, is this even worth trying?  These days is it necessary for Android to be packaged with special drivers and such for all of the different hardware out there?


Spoilers if you didn't see episode 473 of the anime yet:      In anime episode 473, Kakashi uses Obito's eyes to create Susanoo. But Obito's eyes were not Eternal Mangekyou. Previously, he had Rinnegan which he has borrowed in addition to one of his own eyes, and that's why he could do lots of stuff.    Note: this is not the same question as the closure says! Eternal Mangekyou is when someone from Uchiha gives his Mangekyou to to someone dear then it becomes eternal and the powers will be activated.

In chapter 604 of the manga, it is shown that Kakashi kills Rin. This fulfills the requirement to activate the Mangekyou Sharingan. So that should have been the moment when Kakashi was able to use the Mangekyou Sharingan.   Also, the Yellow Flash was still alive when this happens, so this means that Naruto was not yet born. This clearly points to the fact that from the very beginning of the Naruto series, Kakashi had his Mangekyou Sharingan activated.   When Kakashi first fought Itachi (when Itachi and Kisame appear at Konoha) and faced the Tsukuyomi he was devastated in a moment, even though he had his Mangekyou Sharingan active (though not used). But the next time they face (during the rescue mission of Gara), he was able to withstand it.  Now my first question is, was Kakashi unaware of his Mangekyou Sharingan until he faced Itachi, or was he not proficient in using it. Also why in the Naruto series (I mean the series before the start of Shippuden) didn't Kakashi use his Mangekyou Sharingan?  Now for my second question, in the same chapter, a few pages back, just when Kakashi strikes the blow at Rin, Obito's vision starts to fade as he can sense Rin dying. Does this mean Obito's Mangekyou Sharingan was awakened at the same time? We know that Kakashi and Obito shares the same "other dimension" because of the same Sharingan that the both use (not the same eye, but the eye of the same Uchiha). So does the same apply for their activation of Mangekyou Sharingan?


I found out black heats up the most and white the least, as I expected. The question I had is that despite black reflecting all the wavelengths of the visible spectrum, and hence giving the black material its colour, why is it not the coolest?  I mean, even blue. It's reflecting the higher frequencies, which are at a higher energy acc. to E=h*f (f is frequency), why does it get heated more than red?

In my book's thermodynamics chapter, it says that an      "object that radiates heat faster also absorbs heat faster. This means   that an object that is a more efficient radiator comes to equilibrium   with its environment more quickly. With this in mind, is it better to   paint your house black or white?"   I am confused which it would be. The book says white because      "in summer, you house is cooler than the environment and white   reflects away the heat. In winter your house is warmer than the   environment and white radiates away the heat"


I'm looking to remove the write-protection from a USB drive and have done everything I found on the internet. Some examples of what I have done are:  Tried to format it by right-clicking the icon through file explorer and clicking format then ok and by using diskmgmt.msc  Used diskpart, attempted to change it via properties  edit the registry (the key wasn't there)   None of these methods worked. My USB drive is one of the "2 TB" USB (I know, it was probably one of those fake ones from China considering the price I paid was under $20). This has been going on ever since the middle of an h2testw scan to check the real amount of storage. I am currently running on windows 10.0.18363.1016

When I plug in my USB flash drive, it shows up on my computer as write-protected or read-only. I am unable to transfer data to it, nor can I modify or delete any files already stored on it. I also cannot repartition or reformat the drive using Windows Disk Management, DiskPart, GParted, or other tools. The drive does not have a write-protect switch.  Why did this happen and what can I do about it? Is there a way to remove the write protection?  (Note that this can happen with some memory cards, too, as they often use controllers similar to those used in flash drives. In some cases, the system may report that the drive or card was formatted successfully even though it was never actually formatted; the original data reappears when the device is reinserted.)     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


About Me: I am new to C#. So i found this code on Microsoft! int a, b, c; a = 7; b = a; c = b++; b = a + b * c; c = a >= 100 ? b : c / 10; //This Line Is Confusing a = (int)Math.Sqrt(b * b + c * c);  Can Someone explain me why the ? : are used There? What's the use of the "? :"

This came to my mind after I learned the following from :  where T : struct   We, C# developers, all know the basics of C#. I mean declarations, conditionals, loops, operators, etc.  Some of us even mastered the stuff like , , , , ...  But what are the most hidden features or tricks of C# that even C# fans, addicts, experts barely know?  Here are the revealed features so far:    Keywords    by  var by  using() statement by  readonly by  as by  as / is by  as / is (improved) by  default by  global:: by  using() blocks by  volatile by  extern alias by    Attributes    by   by   by   and  by   by   by   by    Syntax    (coalesce nulls) operator by  Number flaggings by  where T:new by  Implicit generics by  One-parameter lambdas by  Auto properties by  Namespace aliases by  Verbatim string literals with @ by  enum values by  @variablenames by  event operators by  Format string brackets by  Property accessor accessibility modifiers by  Conditional (ternary) operator (?:) by  checked and unchecked operators by  implicit and explicit operators by    Language Features   Nullable types by  Anonymous types by  __makeref __reftype __refvalue by  Object initializers by  Format strings by  Extension Methods by  partial methods by  Preprocessor directives by  DEBUG pre-processor directive by  Operator overloading by  Type inferrence by  Boolean operators  by  Pass value-type variable as interface without boxing by  Programmatically determine declared variable type by  Static Constructors by  Easier-on-the-eyes / condensed ORM-mapping using LINQ by  __arglist by    Visual Studio Features   Select block of text in editor by  Snippets by      Framework   TransactionScope by  DependantTransaction by  Nullable<T> by  Mutex by  System.IO.Path by  WeakReference by    Methods and Properties   String.IsNullOrEmpty() method by  List.ForEach() method by  BeginInvoke(), EndInvoke() methods by  Nullable<T>.HasValue and Nullable<T>.Value properties by  GetValueOrDefault method by    Tips & Tricks   Nice method for event handlers by  Uppercase comparisons by  Access anonymous types without reflection by  A quick way to lazily instantiate collection properties by  JavaScript-like anonymous inline-functions by    Other   netmodules by     by     by


I have used this for changing other aspects of the style, but for some reason it won't change the input field colour.... Is it possible to change it this way something like style.background-color: "red";  ?  Other questions seem to make the space where my error message is, highlighted, rather than the actual text box its self.  JS  if (document.getElementById("telno").value == /^\d+$/ ) {             document.getElementById("errtelno1").style.display = "inline";             document.getElementById("errtelno1").style.visibility = "visible";   This is the CSS at the moment  .error{ display: none; color: #FF2121; font-family: arial; font-size: 14px; font-weight: bold; }  h1{ font-style: normal; font-weight: bold; font-size: 20px; font-family: Lucida Sans Unicode; color: #0A032F; text-align: center; text-decoration: underline; }  h2{ font-weight: bold; font-size: 18px; font-family: arial; color: #33257B; text-align: center; text-decoration: underline; }  p{ font-family: arial; font-size: 14px; }  fieldset{ margin-left: 400px; margin-right: 400px; margin-top: 40px;    text-align: center; border: 1px solid #000000; background: linear-gradient(#ffffff, #f2f2f2); }       label{ font-family: arial; font-size: 14px; display: inline; }  .formfield{ margin-left: 25px; display: inline; }  #title{ margin-left: 25px; display: inline; }

Anyone know a simple method to swap the background color of a webpage using JavaScript?


Can we combine two text fields in report, I would like to build a bucket field with combination of two fields.Any other way a part from creating formula field in Object.

is it possible to combine two fields in one and use that field to group by in reports? for example, i would like to combine ee id and ee name fields in 1 and show as 1 field in the "group by" section on reports.


I have been greeting all my professors as "Professor (last name)" in emails I send to them. I think this is normal, but at my university all the professors/lecturers use their first name when ending emails they send.  For example, if the teacher's name was "Joe Smith", they might end an email they send as follows:  Regards, Joe  This behavior is the case with all of the professors I've had, so it seems to be something that's global to the university. Should I be addressing my professors by their first name in emails? I would have done so already, but I don't want to sound disrespectful. I've looked it up but haven't found any guidelines my university gives on addressing faculty.  Also, I think this question is different from others because as far as I know, my university is an exception with all professors using their first name.

I am an undergraduate student working for a professor this summer. Up to this point, I have referred to the professor as Dr. LastName. I have met his research group; his graduate and PhD students refer to him by his first name. Moreover, he signs his emails to me with his first name.  Is it acceptable to ask, through email, how he would like to be addressed? Or is it proper etiquette to wait for him to correct me? I would prefer to ask him in person, but I will not be seeing him for several weeks.   For example, in an email: "I have noticed that you sign your emails as 'FirstName'. Would you prefer that I address you as 'FirstName'?"


Why apt-get install is always slow at this line below?  0% [Connecting to gb.archive.ubuntu.com (2001:67c:1560:8001::14)]   It takes up to 5 to 10 mins sometimes. It just gets stuck there most of time.  For example:  $ sudo apt-get install php-pgsql Reading package lists... Done Building dependency tree        Reading state information... Done The following packages were automatically installed and are no longer required:   gyp libjs-inherits libjs-node-uuid libuv1 libuv1-dev linux-headers-4.8.0-22 linux-headers-4.8.0-22-generic linux-image-4.8.0-22-generic linux-image-extra-4.8.0-22-generic   node-abbrev node-ansi node-ansi-color-table node-archy node-async node-block-stream node-combined-stream node-cookie-jar node-delayed-stream node-forever-agent node-form-data   node-fstream node-fstream-ignore node-github-url-from-git node-glob node-graceful-fs node-gyp node-inherits node-ini node-json-stringify-safe node-lockfile node-lru-cache   node-mime node-minimatch node-mkdirp node-mute-stream node-node-uuid node-nopt node-normalize-package-data node-npmlog node-once node-osenv node-qs node-read   node-read-package-json node-request node-retry node-rimraf node-semver node-sha node-sigmund node-slide node-tar node-tunnel-agent node-underscore node-which Use 'sudo apt autoremove' to remove them. The following additional packages will be installed:   php7.0-pgsql The following NEW packages will be installed   php-pgsql php7.0-pgsql 0 to upgrade, 2 to newly install, 0 to remove and 1 not to upgrade. Need to get 57.7 kB of archives. After this operation, 223 kB of additional disk space will be used. Do you want to continue? [Y/n] y 0% [Connecting to gb.archive.ubuntu.com (2001:67c:1560:8001::14)] Get:1 http://gb.archive.ubuntu.com/ubuntu yakkety-updates/main amd64 php7.0-pgsql amd64 7.0.13-0ubuntu0.16.10.1 [55.8 kB] Get:2 http://gb.archive.ubuntu.com/ubuntu yakkety/main amd64 php-pgsql all 1:7.0+44 [1,920 B]                                                                                Fetched 57.7 kB in 8min 4s (118 B/s)                                                                                Selecting previously unselected package php7.0-pgsql.                                                                                (Reading database ... 258311 files and directories currently installed.)                                                                                Preparing to unpack .../0-php7.0-pgsql_7.0.13-0ubuntu0.16.10.1_amd64.deb ...                                                                                Unpacking php7.0-pgsql (7.0.13-0ubuntu0.16.10.1) ... Selecting previously unselected package php-pgsql. Preparing to unpack .../1-php-pgsql_1%3a7.0+44_all.deb ... Unpacking php-pgsql (1:7.0+44) ... Processing triggers for libapache2-mod-php7.0 (7.0.13-0ubuntu0.16.10.1) ... Setting up php7.0-pgsql (7.0.13-0ubuntu0.16.10.1) ...  Creating config file /etc/php/7.0/mods-available/pgsql.ini with new version  Creating config file /etc/php/7.0/mods-available/pdo_pgsql.ini with new version Setting up php-pgsql (1:7.0+44) ... Processing triggers for libapache2-mod-php7.0 (7.0.13-0ubuntu0.16.10.1) ...   I'm on ubuntu/ kubuntu 16.10.  EDIT:  $ ping -c4 gb.archive.ubuntu.com PING gb.archive.ubuntu.com(steelix.canonical.com (2001:67c:1560:8001::11)) 56 data bytes  --- gb.archive.ubuntu.com ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3056ms   vs  $ ping6 -c4 gb.archive.ubuntu.com PING gb.archive.ubuntu.com(steelix.canonical.com (2001:67c:1560:8001::11)) 56 data bytes  --- gb.archive.ubuntu.com ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3073ms   EDIT 2:  $ which ping /bin/ping  $ ping -V ping utility, iputils-s20150815

I am using Ubuntu 16.04 Beta 2 at the moment and every time I try to update at home via sudo apt-get update or upgrade trough sudo apt-get upgrade I wont get any feedback. Even installing of anything will have the same result. It will just "hang up" on 0% while fetching data.  $ sudo apt-get update [sudo] password for niclas:  0% [Connecting to archive.ubuntu.com (2001:67c:1560:8001::11)] [Connecting to archive.canonical.com (2001:67c:1360:8c01::1b)]   I have no idea how to solve the problem. I already tried to ping6 archive.ubuntu.com with 100% packet loss while just ping wont have any loss.  I changed the DNS-Server (IPv4 & IPv6) to Google's one no solution either.


It'll be nice if a notification is displayed when you're writing an answer to a question and someone else votes it as a dupe. Today, I answered a question and when I submitted, I noticed that it's being voted as an exact duplicate. It was indeed a duplicate so I deleted my answer and voted as a dupe. It would be nice to have notifications like the one that says "2 new answers added to the question" for duplicate votes and closing too.

I have one feature-request with the objective of having duplicate questions with no answers:   To (try to) avoid people answering duplicate questions, add an alert that says the question has a probable duplicate if it has a close vote as Exact duplicate, asking the answerer to go to the original and answer there.   What do you think? My objective is letting the duplicate question exist for search purposes, but the answers centralized in the root question.


I am not just asking how to change the DPI of X11 as a whole, but instead how to make each monitor run on a separate DPI. I am trying to use two 900p monitors (19 inch) and one 720p TV (30 inch).

I'm using Ubuntu 12.04.3 with NVidia drivers (319) for my Quadro K2100M graphic card, and when I switch my main 3200x1800 laptop screen to mode 1920x1080 (using nvidia-settings), the display goes blurry...  I am using two screens:    My main screen is a LCD with max resolution 1920x1200. My laptop screen (original resolution 3200x1800) is sitting to the right of that.   The main problem is that, on Ubuntu, the font is far too small on my laptop screen. Because of that, I wanted to change the resolution of my laptop to 1920x1080.  Reading , I tried to  and here is the DPI configuration which I should have:   94x94 for my main LCD screen 1920x1200 235x236 for my 3200x1800 laptop screen   Is there a way to have dual DPI resolutions with an extended desktop?


If $(x_α)_{α \in A}$ is a collection of numbers $x_α ∈ [0, +\infty]$ such that $\sum_{α∈A}{x_α} < \infty$, show that $x_α = 0$ for all but at most countably many $α \in A$, even if $A$ itself is uncountable.

Let $A$ be an infinite set. For each $a \in A$, let $x_a$ be a non-negative number. Let the value of the series $\sum_{a \in A} x_a$ be the value of the supremum of its finite partial sums, i.e.:      $$\sum_{a \in A} x_a = \sup_{n \geq 0} \sup_{(a_1, \ldots , a_n) \subset A} \left(x_{a_1} + x_{a_1} + \ldots + x_{a_n}\right)$$   (Supremum is well defined even when its value is infinite)       If $\sum_{a \in A} {x_a}$ is finite, prove that the set $A' = \left\{{a \in A | a > 0}\right\}$   is countable.   My guess is that we have to write $A$ as a union of finitely many sets.


I am a beginner so I need a simple example of custom delegates. How we can create, use and call? Step by step explanation would be appreciated. i know that the question asked many times before but still confused. Thanks in advance.

I know how delegates work, and I know how I can use them.  But how do I create them?


"The city was a thousand years a-building."  What does "a-building" (in building) modify in that sentence?

For example,   If this van's a-rockin', don't come a-knockin'  (song title)   (song title)   I have a few related questions:   What is the "a-" or "-a" called? Is there a function beyond a rhythmic one? Why is "a-" attached to a word at all -- and why attach to a word at all?


I'm Using front-end angularjs, there is a file upload option. When I upload a file it will pass to back-end Java Web services and It will insert into database. So this is the flow I have to do.  My problem is, How can I pass the file using JSON AJAX to the web services, Please let me know further any questions required.  Thanks in Advance.

I would like to upload a file asynchronously with jQuery.     $(document).ready(function () {     $("#uploadbutton").click(function () {         var filename = $("#file").val();          $.ajax({             type: "POST",             url: "addFile.do",             enctype: 'multipart/form-data',             data: {                 file: filename             },             success: function () {                 alert("Data Uploaded: ");             }         });     }); });  File <input type="file" id="file" name="file" size="10"/> <input id="uploadbutton" type="button" value="Upload"/>     Instead of the file being uploaded, I am only getting the filename. What can I do to fix this problem?


Hello I have a problem. The checkbox does not show me the field after I have made an append. m = 1; max_fields = 5;      $('.anadir_compania').click(function() {             if(m < max_fields){ //max input box allowed                 var my_html = '
<input type="checkbox" name="operador_virtual[]" value="1" class="custom-control-input" id="operador_virtual_'+m+'">Marcar si eres un operador virtual

Operador<input class="form-control company2_input" type="text" name="company2[]" id="company2" placeholder="Escribe un operador">
';                 m++;                 wrapper.html(my_html);             }         });                      $( ".custom-control-input" ).change(function() {                 if ($('.custom-control-input').is(':checked')) {                     $('.compania2').removeClass('d-none');                     $('.company2_input').prop('required', true);                 }else{                     $('.compania2').addClass('d-none');                     $('.company2_input').prop('required', false);                     $('.company2_input').val("");                 }             });  -------------------------------EDITED: ADDED HTML FOR MORE INFO-------------------------------         Añadir             más compañías

                         <input type="checkbox" name="operador_virtual[]" value="1" class="custom-control-input"                             id="operador_virtual">                         Marcar si eres un operador                             virtual

                     Operador                     <input class="form-control company2_input"type="text"                         name="company2[]" id="company2" placeholder="Escribe un operador">

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


Why does a bird not get electrocuted when it is sitting on a high tension electric wire?

When we touch electric wires, we get shocked. Why don't birds sitting on electric wires not get shocked?


I'm looking for another noun to describe someone who knows things are bad, but doesn't do anything to improve the situation because of fear of the consequences of acting.   Ostrich is the closest I can get but it doesn't fit with the six other labels I'm using; it introduces an unwanted comic element. Also, the ostrich pretends not to know: I'm trying to describe someone who knows perfectly well, but feels paralysed. Paralysis could work but it's not a noun used for a person; I can't use paralytic because that would have completely different connotations.

"The only thing necessary for the triumph of evil is for good men to do nothing." -Edmund Burke  Is there an idiom, phrase or preferably a single word that we can call people that could have helped but didn't? Bystanders don't necessarily have help to give. Cowards aren't particularly helpful either.    Addendum:  For example, once EMS has arrived on scene, bystanders are encouraged not to try to help, unless they're a nurse and therefore have the necessary skills to, and sometimes even then so. If in The Service, I would not want a coward (a liability) next me holding the line. Not to take anything away from these great answers, or to insist on a non-militaristic point of view, I would like to veer into the commercial or civilian realm in which I find this quote most often alluded to, E.G., "If we all gave 5 cents we could cure cancer tomorrow." Pretend most of us did give 5 cents and we did cure cancer, but you didn't give. You are now a(n) ____?... yes, I know what we call them, but what is their proper designation?


$$\arccos\left(\frac{\text{adjacent}}{\text{hypotenuse}}\right)=θ$$  I regard the above as witchcraft. How would I work this out if I didn't have a calculator? Once I know how to workout arcos without a calculator, will I know how to work out arcsine and arctangent? Is it simply a case of swapping around the the adjacent, opposite and hypotenuse?

Stupid question but I need to understand:  If $ \cos = \dfrac{\text{adjacent}}{\text{hypotenuse}} $  What is arcosine? $ \text{adjacent} \cdot \text{hypotenuse}$? Is this the same for arcsine and arctangent?


Inherited the following audit table: Table UserActions AppID int ActionTime datetime Action varchar(25) UserID int Description text  Clustering key is on AppID, ActionTime, Action columns. RowCount = appx 1 billion How do I view the size of this particular clustered index in total and per row?

It is a known fact that the DMVs dont hold accurate information regarding number of pages and count of rows. However, when you have the stats updated, I can't see why they wouldn't.  I am working on a monitoring tool, want to know disk size of each index and data, etc. Eventually I would like to find the right fill factor, and other things etc.  The space used by my function and the old sp_spaceused differs a little bit on the space usage, but not on record count.  Can you see if there is anything missing in my select?  this is the sp_spaceused (then I convert the numbers in MB):  sp_spaceused 'tblBOrderRelationship' go  select 318008/1024.00 AS reserved, 140208/1024.00  AS data, 177048/1024.00 AS index_size, 752/1024.00    AS unused     But when I run my select, code below\picture below, I get slightly different figures.  SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED  SELECT      schema_name(t.schema_id) as SchemaName,     t.NAME AS TableName,     t.type_desc,     t.is_ms_shipped,     t.is_published,     t.lob_data_space_id,     t.filestream_data_space_id,     t.is_replicated,     t.has_replication_filter,     t.is_merge_published,     t.is_sync_tran_subscribed,     --t.is_filetable,     i.name as indexName,     i.type_desc,     i.is_unique,     i.is_primary_key,     i.is_unique_constraint,     i.fill_factor,     i.is_padded,       sum(p.rows)               OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as RowCounts,     sum(a.total_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as TotalPages,      sum(a.used_pages)         OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as UsedPages,      sum(a.data_pages)         OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as DataPages,      (sum(a.total_pages)       OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024 as TotalSpaceMB,      (sum(a.used_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024 as UsedSpaceMB,      (sum(a.data_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024 as DataSpaceMB FROM      sys.tables t INNER JOIN           sys.indexes i ON t.OBJECT_ID = i.object_id INNER JOIN      sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id INNER JOIN      sys.allocation_units a ON p.partition_id = a.container_id WHERE      t.NAME NOT LIKE 'dt%' AND     i.OBJECT_ID > 255  AND T.NAME = 'tblBOrderRelationship'   the figures    the bigger picture, including the index names   Now doing some calculations to check the results:  --================================== -- the figures from sp_spaceused --================================== select 318008/1024.00 AS reserved, 140208/1024.00  AS data, 177048/1024.00 AS index_size, 752/1024.00    AS unused  --================================== -- the figures from my select --================================== select 137+61+56+54 AS reserved,        137 AS data,        61+56+54 AS index_size     It is not so far off, really, apart the fact I did not calculate the unused space!  What can I do to make this accurate?  AFTER CHANGES:  After I replaced 1024 by 1024.00 the results are much more accurate.  I noticed records have been inserted into the table in question, and obviously the stats are not so up to date, but still the results match (under 1 MB difference - which is all right for me)  The new result sets are:  --================================== -- the figures from sp_spaceused --================================== select 318072 /1024.00 AS reserved, 140208 /1024.00 AS data, 177096 /1024.00 AS index_size, 768 /1024.00 AS unused go  --================================== -- the figures from my select --================================== select 137.7578125+61.7968750+56.4218750+54.6406250 as reserved,        137.7578125 as data,        61.7968750+56.4218750+54.6406250 as index_size


$\newcommand{\tr}{\mathrm{Tr }}$ Let be $\mathcal{M}_n(\mathbb{C})$ the set of complex-valued square matrices of order $n$ and $[A, B] = AB - BA$ a commutator.  If, for some $A, B \in \mathcal{M}_n(\mathbb{C})$, we have $[A, [A, B]] = 0$, then $[A, B]$ is nilpotent.  So: $[A, [A, B]] = 0$ says that $A$ and $[A, B]$ commutes.  Let be $\lambda \in \mathbb{C}$ and $X \in \mathbb{C}^n$ such that $[A, B]X = \lambda X$ (an eigenvalue/eigenvector pair), such values always exist as $[A, B] \in \mathcal{M}_n(\mathbb{C})$ and must have $n$ eigenvalues.  Left-multiplication of the previous relation gives: $A[A, B]X = \lambda AX$.  By hypothesis, we have: $[A, B](AX) = \lambda (AX)$.  If we denote $E_{\lambda}$ the set of eigenvectors of $[A, B]$ for the $\lambda$ value, we have: $X \in E_{\lambda} \implies AX \in E_{\lambda}$.  As a result, for all $k \in \mathbb{N}, A^k X \in E_{\lambda}$.  Now, we also have $\tr [A, B] = 0$ because of properties on the trace.  If $A$ is not nilpotent or nilpotent for $k \geq n$, then: $(X, AX, \ldots, A^{n - 1} X)$ is linearly independent, as $\dim E_{\lambda} \leq n$ and $\dim E_{\lambda} \geq n$.  We conclude that $\dim E_{\lambda} = n$, finally: $n \lambda = 0$, now: $\lambda = 0$.  We conclude that $[A, B]$ is nilpotent.  If $A$ is nilpotent for $k \leq n - 1$, then $\dim E_{\lambda} \geq k$.  Here, I don't really know how to proceed, I'd like to show we cannot have any other value than $\lambda$ and it must be $0$ due to the trace.

Let $A,B \in \mathbb{M}_n (\mathbb{C})$. If $A^2B + BA^2 = 2ABA$ then exist $k \in \mathbb{N}$ where $(AB-BA)^k = 0$.  I tried solve with minimal polynomial, but I did not have much effect.


I am a little confused about the proof for the following theorem:     Every finite integral domain is a field.   $R$ is a finite integral domain with $R^{*}$ being the set of nonzero elements of $R$. The proof defines a map for all $a\in R^{*}$ to be $\lambda_{a}(r)=ar$ for $r\in R^{*}$. It showed it was injective. Then this is the part I am confused about: Since $R^{*}$ is a subset of $R$, $R^{*}$ is finite hence must be surjective. Could someone please explain this implication?

Let $R$ be an integral domain, and let $a \in R, a \neq 0$. Let $f_a: R \rightarrow R$ be defined by $f_a(r)=ar$. Prove that $f$ is injective.   Then prove that every finite integral domain is a field.   My ideas and concept:   Can someone help articulate my understandings into a proper solution?


I think  to this  is not a good idea in that one should not really be copying files from a JDK and moving them to a JRE.  I added an answer and a comment to that effect, but my concern is that a user may see the high votes on the original answer, assume it is a good idea, and try it.   Can I use flagging to bring this to a moderator's attention?

The accepted answer is factually incorrect; one can simply call  row.Table.Columns.Contains(name);   What should be done?