The div containing tags for a question doesn't reflow, causing layout issues for questions with long/many tags

This appears to be a css bug which (I think) has recently been introduced. It's most visible when viewing questions on Stack Exchange sites using mobile devices (the full site with responsiveness, not the mobile site) but can easily be reproduced by resizing a browser window on a question where the combined width of the tags is large. A couple of example questions show this behaviour:  On Meta Stack Overflow:   On Meta Stack Exchange:     Using the Meta Stack Overflow question to demonstrate (as the total width of the tags is larger):  At 1100px, the tags just about fit into their containing div.     At 800px, the tags appear on top of related questions:     At 450px, the tags are now wider than the view (the last tag is completely off the screen), causing scroll bars to appear:      This doesn't happen to lists of questions - the tags flow onto multiple lines:     Reproduced on: { Firefox 81, Chrome 84, Edge 84 } on Windows 10, and Chrome 85 on Android 11.


If the total electric energy associated with a field is:    and the electric field of a point charge follows an inverse square law:    then $U_{ES}$ would be infnite if you compute the integral. Can someone shed light on what it means for "infinite total energy" to be associated with a particle?  Secondly, if charges are actually "points" and do not have a finite radius, shouldn't all matter collapse into black holes?   Could someone explain what it means for an electron or other fundamental particle to be associated with a finite radius? What is the "electron radius," and how is it measured? What is self-interaction energy?  equations from


How to create a .desktop file that launchs 2 programs at the same time?

I am trying to make a .desktop file that launches more than one app. This are the commands I tried:  Exec=appcmd & appcmd Exec=appcmd AND appcmd Exec=appcmd && appcmd


What are the costs of books and materials in Harry Potter?

In the first book, Harry sees his Gringotts vault for the first time.  (Quotes thanks to Slytherincess!)     Griphook unlocked the door. A lot of green smoke came billowing out, and as it cleared, Harry gasped. Inside were mounds of gold coins. Columns of silver. Heaps of little bronze Knuts.      "All yours," smiled Hagrid.      All Harry's -- it was incredible. The Dursleys couldn't have known about this or they'd have had it from him faster than blinking. How often had they complained how much Harry cost them to keep? And all the time there had been a small fortune belonging to him, buried deep under London.      Hagrid helped Harry pile some of it into a bag. "The gold ones are Galleons," he explained. "Seventeen silver Sickles to a Galleon and twenty-nine Knuts to a Sickle, it's easy enough. Right, that should be enough fer a couple o' terms, we'll keep the rest safe for yeh."      Harry Potter and the Sorcerer's Stone - pages 58-59 - US Hardcover Edition   Jk Rowling posts in the Harry Potter Lexicon      JKR has stated in an interview (Comic Relief 2001) that she estimates the value of one Galleon to be "about five pounds," which works out to around US$9.75 (the exchange rate at the time of the interview was US$7.33). In the introduction to both QA and FB, US$250-million is stated to be the equivelent of 34 million Galleons. That also works out to a value of £5 to the Galleon, at the exchange rate of the time. The price listed on the back of the books, however, is not correct, since US$3.99 would equal less than half a British pound, or 8 sickles and 15 knuts. The book instead incorrectly lists US$3.99 as being equal to 14 sickles and 3 knuts. (Unfortunately, CNN.com uses this incorrect value for their Knuts-to-dollars converter.)      This gives us approximate values as follows:      1 bronze Knut = £0.01 (US about 2 cents)      1 silver Sickle = £0.29 (about US$0.57)      1 Galleon = £5.00 (more or less US$9.75)      These rates vary as the exchange rate fluctuates - see the Wizarding World Currency Converter for the current rate.   Now looking at the quote      Hagrid helped Harry pile some of it into a bag.   and     Right, that should be enough fer a couple o' terms, we'll keep the rest safe for yeh.   Obviously "some" is unspecified, but presuming the costs of ...     Typical elementary-school textbooks cost more than $100 each   He would be carrying at least 10 galleons for each school book, and going by the list of books just for his first year,  (Thanks Ibid!)     COURSE BOOKS      All students should have a copy of each of the following:         The Standard Book of Spells (Grade 1) by Miranda Goshawk   A History of Magic by Bathilda Bagshot   Magical Theory by Adalbert Waffling   A Beginners’ Guide to Transfiguration by Emeric Switch   One Thousand Magical Herbs and Fungi by Phyllida Spore   Magical Drafts and Potions by Arsenius Jigger   Fantastic Beasts and Where to Find Them by Newt Scamander   The Dark Forces: A Guide to Self-Protection by Quentin Trimble         (Harry Potter and Philospher's Stone, Chapter 5)   That's 80 Galleons just for books. This does not include the list of other expenses Harry has for his school years (wand, potion reagents, etc.)  How many Galleons is "some" or is Diagon Alley selling supplies for third world prices?  Sidenote, is this just a case of bad JK maths?


Why can't I call an operator defined as a friend?

I was trying to define a unary operator+ for a certain type. I was hoping this operator could be used only within the scope of a class, but even if that's not possible, I'm still confused by this:  struct X {};  struct Foo {     friend const char* operator+(X x) { return "hi"; }      void foo() {         +X{};   // error: invalid argument type 'X' to unary expression     } }; int main() {     +X{};   // error: invalid argument type 'X' to unary expression     return 0; }   If the operator isn't callable inside the class, and it's not callable outside the class, is it callable at all? Where did it go?  (Note that +(X{}) behaves the same way, and if the operator+ is moved outside of struct Foo, both calls are valid.)


How to solve large matrix equations involving eigenvalues?

This is a multipart linear algebra textbook question. Let $A, P_1, P_2, N_1, N_2$ be $n$ × $n$ matrices with real entries such that $I_n$ = $(t I_n − A) \big(\frac{N_1}{(t-1)^3} + \frac{N_2}{(t-1)^2} + \frac{P_1}{(t-1)} + \frac{P_2}{(t-2)}\big)$ Then, I'm asked to show the following:  If $\lambda$ is an eigenvalues of $A$, then λ ∈ {1, 2}.  I'm not really sure what my first steps here should be. Given the initial equation, I don't really know what matrix algebra I can apply. I'm wondering first of all how I can even take the determinant of both sides to connect it to eigenvalues Any assistance on this question would be much appreciated!


Is there any proper word for a person who is very hard to please?

I searched on Google - but mainly find "difficult" / "demanding". I am just wondering if there is any more appropriate word?


I need to add files to multiple value file field using drupal rest api (restws module). return format of restws is something like this :  "field_files": [      {         "file": {             "uri": "http://drupal/file/445",             "id": "445",             "resource": "file"         }     } ],   but when I send it to http//drupal/node/<node_id> restws returns not acceptable.  Can anyone suggest which format I must use to send data to?  and second question : How can I upload files using restws module ?


Why Did Gringotts Pay Out for Harry's Firebolt?

In Prisoner of Azkaban, Sirius Black anonymously sends Harry a Firebolt broom after the demise of Harry's Nimbus 2000 in the Whomping Willow. At the end of PoA, Sirius writes Harry a letter and explains that, yes, it was he who sent the Firebolt:     There is something I never got round to telling you during our brief meeting. It was I who sent you the Firebolt –  Crookshanks took the order to the Owl Office for me. I used   your name but told them to take the gold from Gringotts vault number seven hundred and eleven – my own. Please consider it as thirteen birthdays’ worth of presents from your godfather.   Prisoner of Azkaban - page 315 - Bloomsbury - chapter 22, Owl Post Again   Throughout the entire series it's made very obvious that breaching Gringotts' security was punishable by death. Gringotts had tons of security measures in place (and for the sake of this question, I'm not talking about the successful break-in the trio pulled off in Deathly Hallows).     Vault seven hundred and thirteen had no keyhole.   ‘Stand back,’ said Griphook importantly. He stroked the door gently with one of his long fingers and it simply melted away. ‘If anyone but a Gringotts goblin tried that, they’d be sucked through the door and trapped in there,’ said Griphook.   ‘How often do you check to see if anyone’s inside?’ Harry asked.   ‘About once every ten years,’ said Griphook, with a rather nasty grin.   Philosopher's Stone - page 59 - Bloomsbury - chapter 5, Diagon Alley   Why did the Gringotts goblins act on Sirius's written direction that the money for the Firebolt should be taken out of his vault instead of Harry's? Sirius was the most wanted wizard in Britain at the time and it would seem that the goblins wouldn't have followed such suspicious directions so blithely when they received the request for funds from, presumably, Quality Quidditch Supplies for the broom. Why wasn't the Ministry notified that a request for funds from Sirius Black's vault had been made? How is it possible that Sirius was able to purchase Harry's broom via third party? Why did Gringotts pay out?  ★ I'm looking for a canon-based answer (the Harry Potter novels and three supplemental books, any J.K. Rowling interviews with relevant information, or Pottermore). I do not prefer an answer from the HP Wikia/Wikipedia.


Configure up-arrow to browse through commands with same initial characters rather than all previous commands

On the bash command-line, ↑ gives me the previous command. On the command-lines in ipython or matlab, when I type a few characters, ↑ gives me the previously entered command starting with those characters. How can I enable exactly this behaviour in bash? I am aware of more advanced ways of searching through the command-line history, but sometimes a simple way is more convenient.


Showing $\sin(\bar{z})$ is not analytic at any point of $\mathbb{C}$

Use the Cauchy-Riemann equations to show that the function $$g(z) = \sin (\bar z)$$ is not analytic at any point of $\mathbb{C}$.  Here's as far as I got -  $$\sin \left(\frac{\bar z}{1}.\frac{z}{z}\right) =\sin \left(\frac{|z|^2}{z}\right) =\sin \left(\frac{x^2 + y^2}{x+iy}\right)$$  I can't see how to separate the real and imaginary parts so that I can apply the Cauchy-Riemann equations.


How can I remove duplicate subarrays from my multidimensional array?

I have an array:  array:3 [▼   0 => array:1 [▼     "name" => "test#4"   ]   1 => array:1 [▼     "name" => "C"   ]   2 => array:1 [▼     "name" => "C"   ] ]   I want to get only the unique values:  array:2 [▼   0 => array:1 [▼     "name" => "test#4"   ]   1 => array:1 [▼     "name" => "C"   ] ]   What PHP function should I use?   I use array_unique():  $group_array = []; foreach ($private_group_devices as $i=>$group) {     $group_array[$i]['name'] = $group['group_name']; } // dd($group_array); dd(array_unique($group_array));   But I keep getting:     Array to string conversion


Limit of $(1+\frac{1}{2})(1+\frac{1}{4})...(1+\frac{1}{2^n})$ as $n \to \infty$ and the rationality of the answer

What is the Limit of $(1+\frac{1}{2})(1+\frac{1}{4})...(1+\frac{1}{2^n})$ at n = $\infty$?  At first I think it is divergent but it is surely convergent to something between $2$ and $3$. More exactly it is between $2.3$ to $2.4$. something about $2.38$. but I don't know how to find its limit. What can we say about rationality of the answer? (Is it rational or irrational?)  My question is made of two parts. first finding the limit and second, discussing about its rationality.


What are the location based alarm applications available for Android?

I want to know what apps can sound an alarm depending on my location.   Obviously it would be better if the battery consumption is low.  I'd be happy if the application is free but wouldn't mind paying if it's working properly with not much battery consumption. Also please post (if you can) only applications that you've used.   UPDATE: Sorry guys, I should have been more clear. The alarm I am looking for is something where I can set an alarm when I am in the bus/train and make it sound the alarm and wake me up before my stop.


"There's too many numbers" vs "There are too many numbers"

When people use plural nouns after the word "there's", for example:     There's too many numbers.   it makes me a bit frustrated. I try to correct it by using "There are," but it still happens sometimes to me (the "there's" situation). Do you think that there are is the correct usage option?  People usually use there's, as I said.


Too much water in box cake mix batter. Can it be fixed?

I added too much water in my box cake mix and I already mixed the 2 together. What can I do to save the cake? Could I add another box of cake mix to the batter?


Agreed upon domain of inverse trig functions

Why do we choose $[-\pi/2,\pi/2]$ as the domain restriction for $\sin(x)$ when determining $\arcsin(x)$, clearly other restrictions are possible, which also yield a 1-1 function (like $[\pi/2,3\pi/2]$). No pre-calculus book I have seen goes beyond saying that this choice is completely arbitrary. However, I have noticed that every domain restriction for inverse trig functions contains the whole first quadrant in its entirety (with the exception of x values where there are vertical asymptopes). I think these domain restrictions we choose are the only possible choices to get a 1-1 function on a domain that includes "effectively" the whole first quadrant. Is this the reason why we choose these domain restrictions? Are there other reasons why these domain restrictions are more natural than others that would yield a 1-1 function?


Generalization to higher moments of the survival function method for computing the first moment.

If $X$ is a nonnegative random variable, we may compute the first moment by integrating the survival function:  $$ E(X) = \int_0^\infty S_X(x) \, dx $$  Is there a reasonable generalization of this for computing higher moments?


Problem with copying files above ~4.2 GB

I am trying to copy video (mp4) files from the solid state drive of my MacBook Pro to both a external hard disk as well as to a SanDisk USB thumb drive. It goes well up to abut 4.1 GB file size, but for larger files I get an error message "The item "Filename" cannot be copied. The operation couldn't be completed. File too large".   But the file I am trying to copy is only 4.5 GB, whereas there is about 25 GB free space on the USB thumb drive, and about 1 TB on the external hard disk. Does this possibly depend on the file transfer program? First I tried to use Forklift, and then simply Copy and Paste from one Finder window to another. But always the same error message. I checked if there is a limitation on the size of transferred files in Forklift, but did not find any. I would appreciate if someone could tell me where the bottleneck is.


Problem with assigning values to keys in a dictionary

My goal is to create a dictionary with words for keys and lists of line numbers where said words appear as values. The problem is: list of lines is created correctly and assigned as a value to a key word. But each iteration replaces all the values of previous keys somehow, and as a result all values in the dictionary are the same. This is a problem part of my code:    line_list = []      words_lines = {}     # words is a set which contains separate words      for word in words:          line_list.clear()         # text is a list of strings - separate lines of text        for line in range(len(text)):               if word in text[line] and line+1 not in line_list:                  line_list.append(line+1)                  print(word)                     print(line_list)          words_lines[word] = line_list      print(words_lines)


It says in the faq:     If you do not award your bounty within 7 days (plus the grace period), the highest voted answer created after the bounty started with at least 2 upvotes will be awarded half the bounty amount. If there's no answer meeting that criteria, the bounty is not awarded to anyone.   Then why I did not get half of bounty for this question:   I need to mention that the author accepted the answer and then declined it; might have something to do with that.


Would running Ubuntu (or another distro) on my low spec computer instead of windows improve performance much?

Trying to get the most out of a low-end HP laptop running windows 10 It runs alright provided I don't open more than 2 intensive programs at once. I've used Ubuntu on it before (dual boot) but did not fully switch over was mostly just trying out different OS. Is there an advantage performance wise?  My  Also, the hard drive is almost 30G but mostly taken up by windows, I use a USB for storage of programs and pictures  And sorry if anything here seems stupid, I'm new to the site


Direct product, semidirect product and central extension are different types of group extensions. Is there any other type? If there is, can you please give an example with a small finite group?


How to model this odd-shaped distribution (almost a reverse-J)

My dependent variable shown below doesn't fit any stock distribution that I know of.  Linear regression produces somewhat non-normal, right-skewed residuals that relate to predicted Y in an odd way (2nd plot).  Any suggestions for transformations or other ways to obtain most valid results and best predictive accuracy?  If possible I'd like to avoid clumsy categorizing into, say, 5 values (e.g., 0, lo%, med%, hi%, 1).


Must the graph of a linear model always be a straight line of the form $y=mx+b$?  I think that yes, but am checking, whether there might be some exceptions.


Extract image associated to a file based on the extension

I want to get the image associated to a file based on the extension.  for example: \100xadmin\100xredirectedfolders$\elianf\Desktop\WORK\Query Coalesce.txt   I just want to get image related with .txt extension.


What is color?  “The property possessed by an object of producing different sensations on the eye as a result of the way the object reflects or emits light”…. You might say.  So take a white object and paint it “red”. What property of the paint now makes the object appear red?  “Pigmentation!” … you might say.  Good. Now that I’ve got you thinking in line with what I’m thinking, please help me understand what pigmentation actually is. I’m looking for an explanation that goes down to the microscopic level. What is it about the elemental structure of different pigmentation that alters the way that pigmentation (color) is seen by our eyes when applied over an object?


Permutation tests assume exchangeability of the response/observations under the null hypothesis. In what practical situations is this clearly violated? When is it unproblematic? Edit/additional question in order to not be considered as duplicate: if we permute within additional blocking structure (e.g. patients) and sum up the test statistic across blocks, we would only need exchangeability within block, right? PS: I am not looking for tests to verify this symmetry condition as it is a condition under the null, not of the observed data...


I need to create a list as a function of two variables, but the output from that list is different from the output from another list created manually (both list are equal). Here is the code: from math import factorial n=4 k=3 ntuples=int(factorial(n-1)/factorial(k-1)) B=[[1]*k]*ntuples A=[[1,1,1],[1,1,1],[1,1,1]] print(A==B) m=0 n=0 for i in range(len(A)):     A[i][m]=A[i][m]+1     m+=1 for j in range(len(B)):     B[j][n]=B[j][n]+1     n+=1 print(A) print(B)  output:  True [[2, 1, 1], [1, 2, 1], [1, 1, 2]] [[2, 2, 2], [2, 2, 2], [2, 2, 2]]  I want to get the output of A, but using B list. What am I doing wrong? Thanks!


How can I determine what hosting provider hosts a site?

Is there a service that will identify where a site is hosted (presumably by IP)?


How do I make a subdomain (e.g. mirror.site.com) on a LAMP server?

I pretty much want to make a main site that's a proper site, then a subdomain (I think that's what it's called) so I can also make a thing where you go through the folders (the "Index of /folder/folder/file" thing (don't know the proper name).  Sorry for the horrible explanation.


what changes when you install a package in linux

i wanted to know what happens in the background when you install a package in linux?


How do I show that $S_n$ is generated by the set $\{(1\space i), i=2,3,...,n\}$?  Is it correct to say that since each product of elements of $\{(1\space i), i=2,3,...,n\}$ is an element of $S_n$, we know that $\{(1\space i), i=2,3,...,n\}\subset S_n$, and how can I prove that $S_n\subset\{(1\space i), i=2,3,...,n\}$?


What is the physical explanation of the statement "magnetic force is vector product of velocity of charged body and magnetic field"?

If a charged particle is projected under the influence of magnetic field, magnetic force acts perpendicularly with both the direction of magnetic field and velocity of particle. The direction can be calculated by vector product rule.                    But, my question is that why does the force act normally to both the direction? In other words, what is the physical explanation of the statement "magnetic force is vector product of velocity of charged body and magnetic field"?


#1093 - You can't specify target table 'new_keyword' for update in FROM clause

I have query like this   update new_keyword set key_count=key_count-1  where  id in     (select b.id  from new_keyword b ,new_news a ,new_mudoal_label c where c.label_id=b.id and a.id=c.id and c.type=1 and c.id=186)    The sub query return id for exmple (1,2,3) but mysql show me error


Adding datetime.time objects to each other in python

How can i add datetime.time objects to each other? Lets say i have:  import datetime as dt  a = dt.time(hour=18, minute=15) b = dt.time(hour=0, minute=15)  #c = a+b???   c should be equal to datetime.time(hour=18, minute=30)  Edit:  I have a function that gets as arguments datetime.time objects and should return datetime.time object that is sum of passed arguments. As i am only dealing with hours and minutes i wrote this:  def add_times(t1, t2):     hours = t1.hour + t2.hour     minutes = t1.minute + t2.minute     hours += minutes // 60     minutes %= 60     new_time = datetime.time(hour=hours, minute=minutes)     return new_time   But it is a dirty way and i am sure there is a legit way of doing it.  How do i achieve that?


Committing fouls during celebration time

If a player scores a goal and in the time between the goal and the kick off again, if an opponent player pushes or punches the goal scorer, what kind of action is taken? (The conceding team might do this because they're salty) After a goal a free kick cannot be given because a center start is done.


Why is there both `:=` and `=` used in set notation?

I see two kinds of equal signs in different resources in regards to defining sets. One is := and the other is =   An example : S = {1, 2, 3} or S := {1, 2, 3}  I realized that resources concerned with mathematical analysis uses the latter whereas others use the former.  Is there any difference in the meaning of both notations?


Algorithm for finding Time Complexity of Algorithm

I understand that it is possible to analyse code and manually calculate the time complexity of an algorithm by hand and then determine the Big O notation. However I am curious if an algorithm exists to automatically compute this problem.


I need to use xp_cmdshell in one of SQL job.So is it safe to reconfigure xp_cmdshell to 1 or can i set value 1 in the starting of SQL statements and set it back to 0 in the end of SQL Statement ?


If I cancel when prompted for my Git password, I can no longer see anything I type, until I log back in

Everything still works (typing "exit", for instance, exits), but I can't see anything I type. There's not "funny characters", just nothing. Even re-running git and entering the password properly doesn't work.  How do you turn the display of typed characters back on?


C++ - template classes, header files and duplicate errors

When I have a class that's declared completely within a header file (templated types), and that header file is included by multiple cpp source files, compilation errors appear to be reported once per source file that includes the header. So, if I have a header that's used in 8 different places, each error is reported 8 times.  Suggestions? Do I have to live with this, am I doing it wrong, or what?  Edit  Aside from just being generally annoying, this also messes up the error popup when hovering over the red squiggly line in VS. Yay.    (Using Visual Studio 2012)


I'm  installing Ubuntu on a Samsung evo 850 SSD drive. System has 4GB memory but no other harddrive. Should I use thedefault partition table or install without swap and make a swap file after installation? Or does it even make a difference whether it’s a partition or a file?


I am confused about the usage of the words like and unlike in sentences. Like and unlike make me confused because I see them being used everywhere almost interchangeably, and to make matters worse I even saw commas making difference in meaning.  Which of the following sentences is most correct, and least ambiguous?      Unlike Xbox, Playstation can't play Halo.     Playstation can't play Halo unlike Xbox can.     Playstation can't play Halo, unlike Xbox can.     Like Xbox, Playstation can't play Halo.     Playstation can't play Halo like Xbox can.     Playstation can't play Halo, like Xbox can.     Playstation can't play Halo unlike Xbox.     Playstation can't play Halo, unlike Xbox.     Playstation can't play Halo like Xbox.     Playstation can't play Halo, like Xbox.    In case you don't know what I actually wanted to say in those sentences: I'm trying to say that Playstation can't run the Halo video game and Xbox can run that game. I probably should have tried sentences with no brands but I can't imagine any meaningful sentences at this moment which contains like/unlike.


Is there any word for a person who gives the contract to murder to someone else?

Is there a word for a person who doesn't commit murder himself but gives the contract to murder to someone else?


How can I trust any Repositories  like   sudo add-apt-repository ppa:upubuntu-com/tor  or  sudo add-apt-repository ppa:wagungs/Kali-linux


Which lubricant/grease to use for ball bearings?

A little mishap happened today during cleaning my bicycle. I tried to take off the sprocket wheel for easier access, but instead I opened the lock nut of the hub (cassette type) and the balls came out.  Before I can put this mess back together I got some questions:   What kind of lubricant/grease do I need for the ball bearings? There are two ball bearings in the wheel. One with smaller balls (the one on the sprocket wheel side), the other has bigger balls. Former used some black grease while the latter used a green, jelly-ish one. I'm confused, do they need different types of grease? To solve my initial task: How would you get the sprocket wheel off of the wheel/hub/cassette? Does this require a special tool? I tried pulling, but I'm afraid to break something when pulling too hard.


Calculate number of days from date to today

I have tried and looked for the answer to calculate the number of days from a date to  today's date and getting an error.     Calculated columns cannot contain volatile functions like Today and Me.   Any help would be great.


C++ Overloaded operator is not exported to dll

I'm creating this simple struct (Windows 10, g++10.2 Mingw-64): #ifndef GEARSETDATA_H #define GEARSETDATA_H  #include "Helpers_global.h"  #include <cmath>  namespace Helpers {  template<class T> struct HELPERS_EXPORT GearSetData { public:     T pinion, wheel;     GearSetData(const T &pinion = T(), const T &wheel = T()): pinion(pinion), wheel(wheel)     {     } };  template<class T> HELPERS_EXPORT bool operator==(const GearSetData<T> &gearSetData1, const GearSetData<T> &gearSetData2) {     return ((std::abs(gearSetData1.pinion - gearSetData2.pinion) < 1.0e-9) && (std::abs(gearSetData1.wheel - gearSetData2.wheel) < 1.0e-9)); }  }  #endif // GEARSETDATA_H  It is using the definitions from the file "Helpers_global.h": #ifndef HELPERS_GLOBAL_H #define HELPERS_GLOBAL_H  #if defined(_MSC_VER) || defined(WIN64) || defined(_WIN64) || defined(__WIN64__) || defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__) #  define DECL_EXPORT __declspec(dllexport) #  define DECL_IMPORT __declspec(dllimport) #else #  define DECL_EXPORT     __attribute__((visibility("default"))) #  define DECL_IMPORT     __attribute__((visibility("default"))) #endif  #if defined(HELPERS_LIBRARY) #  define HELPERS_EXPORT DECL_EXPORT #else #  define HELPERS_EXPORT DECL_IMPORT #endif  #endif // HELPERS_GLOBAL_H  The problem I have is, that the struct itself is exported as expexcted, the operator == however is not. During the compilation I get the following error message.  error: function 'bool Helpers::operator==(const Helpers::GearSetData&, const Helpers::GearSetData&)' definition is marked dllimport  If I change HELPERS_EXPORT to DECL_EXPORT for the operator it compiles sucessfully. Do you have any idea why the struct is exported as expected and the operator is not? And why does it work is work when I change the "export keyword"?


Prove that a standard torus is diffeomorphic to $ \mathbb S^1\times \mathbb S^1$

I was asked to prove that a standard torus(which means we don't consider those pathological cases where it intersects with itself, e.g horn torus) is diffeomorphic to $ \mathbb S^1\times \mathbb S^1$.  I was thinking if we could prove it this way: Since every point on the torus can be uniquely defined with a pair of angles $(\theta_1, \theta_2)$. Then we construct a diffeomorphism $\phi(\theta_1, \theta_2)=(\tilde{\theta}_1 ,\tilde{\theta}_2)$ which maps every point on the torus to every point on $\mathbb S^1 \times \mathbb S^1$. Since the map is definitely bijective and smooth with a smooth inverse. We're basically done...  THERE MUST BE SOMETHING WRONG I THINK.  Thanks a lot for everyone's help!


Construct disjoint sequence of infinite subsets of $\mathbb{N}$ whose union is not $\mathbb{N}$

Possible to construct a disjoint sequence of infinite subsets of $\mathbb{N}$ whose union is not $\mathbb{N}$?   I am thinking this must be possible.  I've considered trying to define each sequence as the range of some function. I have to find a way to hop over natural numbers in some way to leave infinitely many left for each subsequent subset of $\mathbb{N}$. Thinking about just leaving out $1$ so then the union isn't $\mathbb{N}$. I haven't tried to do anything like this before. Any possible hints on how this can be done and I can think a little more to see if I can come up with something? If not I may just ask for an answer heh.  Thanks much for your time and input I appreciate it very much.


Cannot access network from LXD container created by the ubuntu-sdk

I've created an LXD armhf image from inside the ubuntu-sdk, and I can launch it successfully. However, this image is not able to access the network: any execution of apt-get install ... will fail with similar errors:   E: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/pool/universe/libs/libsdl2/libsdl2-dev_2.0.2+dfsg1-6ubuntu2_armhf.deb       Temporary failure resolving 'ports.ubuntu.com'  E: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/pool/universe/libs/libsdl2-mixer/libsdl2-mixer-dev_2.0.0+dfsg1-5_armhf.deb      Temporary failure resolving 'ports.ubuntu.com'   There are no ifconfig, route, wget or even ping commands inside the image, so I have no clue on how to debug this. Note that this happens only inside the LXD container: from my machine, I can access internet without any issues.


When I share images with the folks in , I frequently find myself double posting just so that I can explain what the image is about or why I bothered posting it. For example:    Addind any text other than the link  prevents it from being oneboxed. That means that if I have to post the image alone. If someone finds it interesting and stars it, an ugly imgur link gets added to the transcript. Others have to click on it to have a clue what it is about. My Suggestion In addition to the current oneboxing... If the entire message consists of [MESSAGE](LINK) and that link is otherwise oneboxable, just onebox it and display the message above it. For example, the following message would show an image of the weather with "Hello, cold, rainy world!" floating above it. [Hello, cold, rainy world!](http://i.stack.imgur.com/jYXpI.png)


what is the meaning of %< in printf statement?

i get </ttd> instead of 	 in the below printf. Can someone please explain why. i want % symbol in my output. But it adds extrac t in my output.  awk '{printf("%0.2f`%</td>`\n",$0)}'   bash-4.3$ echo "50" | awk '{printf("%0.2f	\n",$0)}' 50.00	 bash-4.3$ bash-4.3$ echo "50" | awk '{printf("%0.2f%	\n",$0)}' 50.00%</ttd> bash-4.3$


Interpretation of main effect when interaction term is significant (ex. lme)

As an example I use Pinheiro, J. C. & Bates, D. M. 2000. Mixed-effects models in S and S-PLUS. Springer, New York. page 225. Rats whose body mass has been measured are fed by 3 different diets over time.   Response: Body mass, fixed effects Time*Diet, random effect ~Time|Rat. The main question with this test was if the interaction term is significant (i.e. difference in growth rate between diets). However, my question is could I also look at the p-values of the main effects to say that body mass increased significantly with time for Diet1 (which is the "dummy variable")?   From Pinheiro, J. C. & Bates, D. M. (2000)   Fixed effects: weight ~Time * Diet                   Value        St.error         DF        t-value         p-value   Intercept       251.60         13.068         157         19.254          <.0001  Time              0.36          0.088          13          4.084          0.0001  Diet2           200.78         22.657          13          8.862          <.0001  Diet3           252.17         22.662         157         11.127          <.0001  Time*Diet2        0.60          0.155         157          3.871          0.0002  Time*Diet3        0.30          0.156         157          1.893          0.0602    As stated by Pinheiro & Bates, the growth rate of diet 2 (TimeDiet2) differs significantly from diet 1. Although could I state like this for the effect of time on Diet1: f(x) = 251.60 (+/-13.068) + 0.36 x (+/- 0.088), t = 4.084, p = 0.0001? I have seen that people have claimed that it is wrong to interpret p-values for the main effects when the interaction is significant. And is it more proper to split the data and run the test  (weight ~Time) for each diet separately, when only looking at the effect of  time on body mass?


When leaving the US do you have to go through customs?

A friend of mine went recently to the USA, and he was saying that he didn't go through customs when leaving. After asking at the information balcony in the airport he was told not to worry. Everything would be handled at the departure gate. Only the ticket was checked though.  Is this normal? how do they register the exit?


Why don't we use the proper terminology for linear and affine?

Why do we call y = mx + b linear (in high school)? Why don't we call it affine?  and linear what is actually linear  $$f(x+y)=f(x)+f(y)$$ $$f(ax)=af(x)$$


Underlined math in a Beamer presentation: felt-tip marker underlining

I am composing a Beamer presentation, and I would like to underline some mathematical entities for emphasis.  I am aware of the ulem package, however for a presentation I would like something more visually pleasing, and I was thinking about a felt-tip marker effect, bold and slightly irregular, along these lines:    or also    I must be able to underline just parts of a mathematical expression.  Is there any package I can use to achieve such an effect?


Creating bounding extent of existing polygon with same geometry using QGIS?

I have a number of polygons (in the hundreds) that have been taken from a cadastral layer and I am trying to create another polygon layer based on that group of polygons (from a field ID) without digitizing if possible?  I have looked at the convex hull tool in QGIS but it only creates the minimum boundary I am looking for an exact replica of the exisitng polygons - essentially removing all the parcels and being left with a singlepart polygon of the area.  I have access to ArcGIS as well if there are any tools suitable ?    and what I want to achieve is:


Basic Web Development IDE/Editor like Dreamweaver?

I've used Windows for many years, using Dreamweaver as my editor as it had a file tree which is based on a project (via Local, FTP or SFTP).  I need a web development IDE with the following functionality:   syntax highlighting for PHP, HTML, CSS, JavaScript  file tree - Local, FTP, SFTP, Project-Based (e.g. via the methods of Local/FTP/SFTP) in other words, like Dreamweaver can open multiple files (tabbed)   Additionally, I wouldn't mind features like debugging, class listings, etc, as long as I can hide them away.


What hook can I use for post-save actions?

I've found several posts with this same question, but the answers always diverge to some other topic or they don't work for my needs.  After a node is saved, I want my custom module to insert a row into one of my custom tables which contains the nid of the new node. When hook_node_submit is called, the nid doesn't exist yet. hook_node_insert does have the nid, but only gets called the first time the node is saved, but I potentially need to take action each time the node is saved.   My plan is to separate my functionality into its own method and implement both hooks, but I'm trying to learn to do things properly with Drupal and so I'm wondering if there is a hook that actually fits with my requirements.  Is there a hook which is called every time a node is saved and called AFTER the save is complete?


Connected, locally connected, path-connected but not locally path-connected subspace of the plane

I am looking for a set in the plane (with respect to the natural Euclidean topology) that is connected, locally connected, path-connected but not locally path-connected. I did not find one in , but maybe I overlooked?


Erratum in Griffiths Electrodynamics (wrong reference is made)

I have the Fourth Edition of Introduction to Electrodynamics by David J. Griffiths, published by Pearson.  I have found this erratum in Chapter 5 Magnetostatics, page 234 .     We can see that "Product rule number 6" is written and no asterisk or dagger is there, so I looked in Chapter 1 and found this on page 21    The "rule" which he is using is actually rule number 4.    I have seen the list of errata in the  but couldn't find it.


What is the right ffmpeg output format for playing a video to webcam using v4l2-loopback in linux?

please can someone show me the new syntax for sending videos to webcam using ffmpeg and v4l2loopback?  It used to work perfectly until I updated and upgraded recently  the previous syntax i use is:  sudo modprobe v4l2loopback  ffmpeg -an -re -i inputvideo.mp4 -f v4l2 -vcodec rawvideo /dev/video0   and the error I get is:  [v4l2 @ 0x55a452b3a400] ioctl(VIDIOC_G_FMT): Invalid argument Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument Error initializing output stream 0:0 --  Conversion failed!   I attached a screenshot of the error message   The full code with the error is:  ffmpeg -an -re -i virtualcam.mp4 -f v4l2 -vcodec rawvideo /dev/video0 ffmpeg version 3.4.2-2+b2 Copyright (c) 2000-2018 the FFmpeg developers   built with gcc 7 (Debian 7.3.0-21)   configuration: --prefix=/usr --extra-version=2+b2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared   libavutil      55. 78.100 / 55. 78.100   libavcodec     57.107.100 / 57.107.100   libavformat    57. 83.100 / 57. 83.100   libavdevice    57. 10.100 / 57. 10.100   libavfilter     6.107.100 /  6.107.100   libavresample   3.  7.  0 /  3.  7.  0   libswscale      4.  8.100 /  4.  8.100   libswresample   2.  9.100 /  2.  9.100   libpostproc    54.  7.100 / 54.  7.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'virtualcam.mp4':   Metadata:     major_brand     : isom     minor_version   : 512     compatible_brands: isomiso2avc1mp41     encoder         : Lavf58.16.100   Duration: 00:08:08.36, start: 0.000000, bitrate: 377 kb/s     Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 376 kb/s, 22.77 fps, 22.77 tbr, 11384 tbn, 45.54 tbc (default)     Metadata:       handler_name    : VideoHandler Stream mapping:   Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native)) Press [q] to stop, [?] for help [v4l2 @ 0x55a452b3a400] ioctl(VIDIOC_G_FMT): Invalid argument Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument Error initializing output stream 0:0 --  Conversion failed!


How to let Python recognize both lower and uppercase for the input?

I am doing my homework now and want to make python recognize both lower and uppercase for the input. Here is the script:  print("Welcome to the student checker!")  student_lists={"Mary A","Tony Z","Sophie L","Zoe J","Joey M","Connie O","Olivia L","Mark Z","Donny M"}  while True:      name=input("Please give me the name of a student (enter 'q' to quit):")      if name in student_lists:         print("Yes, that student is enrolled in the class!")      else:         print("No, that student is not in the class.")      if name=="q":         break  print("Goodbye!")   Please let me know how to fix it. Much appreciated!!


Closed form of $\sum_{r=1}^{n}2r*3^{n-r}$

The closed form for this sum, $$\sum_{r=1}^{n} (2r) 3^{n-r}=\frac{1}{2} \left(-3 + 3^{1 + n} - 2 n\right)$$ is quoted in my textbook. How would I derive it?


Night vision camera got a picture but it was just a blank white rectangle from the license plate lights. Is there any way to get the numbers?

Recently, we had a problem with people doing donuts in our parking lot. We have the cameras in place but the night vision camera couldn’t see the license plate because of the lights that illuminate the plate. It looked like a blank, white rectangle where the license plate should be.   Is there anything I can do in Photoshop or something of the sort in order to get the plate numbers?


A word meaning a choice made for self advantage

A word for a choice that is made by someone to his advantage, but somewhat against his principles. Begins with 'co' I think. Not 'pragmatic'. More a suggestion  of manipulation, deviousness, slightly cynical, compromising for gain.


I want to hide a column on the NewForm of a list but it should be visible on the EditForm.  How to do this?


Can we shoot photos with a very shallow DoF with the Lumix FZ300 at any focal length?

I couldn't find that information anywhere. Lot says you can't get a shallow DoF with a tiny sensor. So, anyone has got an FZ300, Can you?  mattdm, that question was about all p&s's in common, I posted this question because I saw a video which was shot by this camera, that had a lot of shallow DoF shots. So I need to know if this camera can shoot photos with a shallow DoF at any focal length.


how to set system wide proxy address in Ubuntu 18.04 LTS server

I install ubuntu server 18.04 LTS distribution without specifying the proxy address during installation and I am having a challenge in setting the systemwide proxy address...


Gravitational constant in higher dimensions?

From Newton's law of gravitation we know that  $$F=G\frac{m_1m_2}{r^2}$$  where $G$ is gravitational constant. We can also see that it has dimensions  $$[G]=\frac{[L]^3}{[M][T]^2}$$  and we have a good numerical estimate of its value ($G\simeq 6.67\times 10^{-11} N(m/kg)^2$).  I've read (for instance in the paper I'm currently mostly interested in, Kerr/CFT correspondence) that in higher dimensions, there are 4 dimensional gravitational constant, and in the search for explanation of it, I've also found that in string theory we have gravitational constants of higher dimensions.  But I haven't seen any formula that would give me mean to calculate it in higher dimensions.  Is there such a thing, or is the definition of it theory dependent?


Convert all geo TIFF in a directory in ASCII

I would like to convert all geoTIFF in a directory in ASCII with the use of a command like gdal_translate -of GTiff... in OSGeo4W Shell.  Is this possible?


I upgraded Ubuntu version 11 to ver 13.04. When I try to download anything like "openvpn" a message of "Failed to fetch openvpn and 404 File not found" occurs. It also says the software cannot be authenticated.  It seems to be attempting to access Nz.archives.com without success. This happens in Software Center, in the terminal with "apt-get install" and in synaptic package manager. Is a tweak possible or is Ubuntu no longer compatible with this HP-Compaq Desktop? I also have "software Updater" on this machine but it won't work and suggests I "check the internet connection." My connection is great to all three of my machines so what gives?


how can I convert a negative log likelihood to likelihood?

how can I convert a negative log likelihood to likelihood between 0 and 1 ?   I use HMMs package in R and  I keep getting strange results of the log likelihood for example, -48569 ! I need to understand these values so I can pick the best model. any advice will be appreciated.  thanks


Considering Hawking radiation, can an object ever actually cross event horizon of a black hole?

The Schwarzschild solution of Einstein's field equations clearly shows that a far away observer sees time slow down for an in-falling object. Relative to him, it takes an infinite amount of time for the object to reach the event horizon. But all black holes evaporate by Hawking radiation in a long but finite time. So wouldn't the observer see the BH completely evaporate away before any object reaches its event horizon?   What would an in-falling person experience? In a very short finite proper time, he would expect to reach the event horizon. But since the BH lost mass, the event horizon would have shrunk. It would keep shrinking away from him, until its radius is zero and the BH is gone. Would he see an explosion at this time and then be in free space in the far future?   Considering time dilation of particles collapsing to form a BH, it seems that neither an event horizon or singularity could ever form in a finite time. Astronomical BHs would really be concentric shells of matter that have almost, but not quite, shrunk within their Schwarzschild radius. Does this seem reasonable?


I have a list [1, 2, 3, 4, 5, 6] and I want to write a for loop to get an output that looks like this: [1,2], [3,4], [5,6]  Most answers that I found online end up giving [1,2], [2,3], [3,4], [4,5], [5,6], but that is not what I want. I did try options such as: s = [0,0,0,1,1,2,1,3]  for value in zip(s, s[2:]):     print(value)  but that did not help.


How to open a file in the same display I am working it?

I have connected a LCD to my laptop. When I try to open a file in Nautilus, the target application opens in my laptop display, rather than the second display (in which nautilus window is open).  I don't want to change the default display. I want to open windows in the display I am working in. If my file manager is in laptop display, I want the apps to open in laptop display. If my file manager is in external display, I expect to open files there.  The output of xrandr  Screen 0: minimum 320 x 200, current 3286 x 1080, maximum 32767 x 32767 eDP1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 256mm x 144mm    1366x768       60.1*+    1360x768       59.8     60.0      1024x768       60.0      800x600        60.3     56.2      640x480        59.9   VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 connected primary 1920x1080+1366+0 (normal left inverted right x axis y axis) 527mm x 296mm    1920x1080      60.0*    50.0     59.9      1920x1080i     60.1     50.0     60.0      1680x1050      59.9      1280x1024      75.0     60.0      1440x900       59.9      1280x960       60.0      1280x800       59.9      1152x864       75.0      1280x720       60.0     50.0     59.9      1440x576i      50.1      1024x768       75.1     70.1     60.0      1440x480i      60.1     60.1      832x624        74.6      800x600        72.2     75.0     60.3     56.2      720x576        50.0      720x480        60.0     59.9      640x480        75.0     72.8     66.7     60.0     59.9      720x400        70.1   DP1 disconnected (normal left inverted right x axis y axis) HDMI2 disconnected (normal left inverted right x axis y axis) VIRTUAL1 disconnected (normal left inverted right x axis y axis)


Key input without pressing enter? (LINUX)

So i'm trying to make something that waits for a user to press a key, and it stores whatever key they pressed in a variable without pressing enter. I heard of mscvrt but that only works on Windows, but i'm trying to make this on linux. Any ideas?


To show that $\lim_{n\rightarrow\infty}$ $\frac{n^{2}}{2^{n}} = 0$

We need to show that that $\lim_{n\rightarrow\infty}$ $\frac{n^{2}}{2^{n}} = 0$. This makes sense intuitively since exponentials always rush to infinity faster than do polynomials, but I don't know how to prove it. Cool thing is, this is actually not from a math class, but from my CS class, where we have to compare runtimes. Regardless, can someone show me how to prove this without using differentiation? Thanks!


Better performance to have nullable columns or an extra table?

There are many ways to get rid of nulls in tables, and I have heard of various reasons to get rid of them, but can anyone show me some real numbers as to how your database might perform differently using different models?  One Table:  A    B    C 1    La   NULL 2    Moo  7 3    Ba   9 4    La   NULL   OR These two tables:  A    B 1    La 2    Moo 3    Ba 4    La  X    C 2    7 3    9   Which is better?  (X is Foreign key to A)  The second set of tables would remove the nulls from the first design. When would be better to use each design?  This second pair of tables would achieve the same result, however it would be more flexible by naming the column as a cell:  First model (A, Arms Legs):  A    Arms    Legs 1    NULL    NULL 2    NULL    2 3    4       2 4    NULL    NULL 5    1       NULL   Second Model (XYZ):  X     Y     Z 2     Legs  2 3     Arms  4 3     Legs  2 5     Arms  1   The second one would remove nulls, but at what compromise?


LaTex by default sets fairly small spaces around "divide" symbol (|). Is there a way to force larger skip (e. g. force LaTex to treat | as binary operator or = symbol)? MWE would be fairly simple:  \documentclass{article} \begin{document} What is set by default:  $a|b$  What I want:  $a\hspace{0.28em}|\hspace{0.28em}b$ %for some reason I can't use mu in \hspace, but 1mu=1/18 em and 0.28em=5mu=\thickmuskip. \end{document}


How to avoid null insertion in ArrayList?

How to avoid null insertion in ArrayList while inserting element?  ArrayList<String> al=new ArrayList<String>(); al.add(null);//should avoid . . . al.add("Ramesh");


"Airport-friendly" suspenders (braces) with AIT

I regularly wear  with "airport-friendly" plastic clasps, designed to be worn under your shirt.  However, I will be traveling to an airport that used Advanced Imaging Technology (AIT) full-body scanners, and I wanted to get an idea of what to expect.  Depending on the answers, I may just leave them off and pray my pants stay up until I can get to a restroom, which is a tall order given my body shape.  Assuming I opt to leave them on:   Do they trigger an alert? If so, am I better off requesting a pat down from the beginning? If I get a pat down, will they make me remove them anyway? I am traveling with my five year-old daughter.  How can I keep a pat down from affecting my ability to keep an eye on her?


I'm suspicious about ONLY ONE thing. Do I have a doubt or doubts then?

The question rooted from the comment of J.R. on  He edited my answer making 'a doubt' 'doubts'. In the comment it's mentioned that if I'm suspicious about something, generally it's expressed in a plural way. But in my answer, I had only one doubt that she meets someone which is out of my knowledge.  Now the question:   If I'm suspicious about only one thing, do I have a doubt? or doubts?  Note: In India, as I said there in my comment, it's quite clear. I have a doubt if I have a doubt and I have doubts if I have them many. In fact, I have many doubts is also common. In my dialect, I'm clear and pretty sure about it but posting this question to learn further.


Recently, we bought a "HP-DL380 G6 Server" with 6 146GB (SCSI)HDD for our colleague course management application and website with 10000 daily visitors.  we want to choose the best RAID level. how can we choose the right RAID level ? what is the best RAID level for our application ?


$f$ is constant if derivative equals zero

Suppose $f'(x)=0$ for all $x\in (a,b)$. Prove that $f$ is constant on $(a,b)$.   This seems painfully obvious, but I can't prove it rigorously.  $f'(x)=0$ for all $x\in (a,b)$ means that for any $c\in(a,b)$, we have $$\lim_{x\rightarrow c}\frac{f(x)-f(c)}{x-c}=0$$ So for any $c\in (a,b)$, for any $\epsilon$ there exists $\delta$ such that if $|x-c|<\delta$ then $$\left|\frac{f(x)-f(c)}{x-c}\right|<\epsilon$$ which also means $$|f(x)-f(c)|<\epsilon\delta$$ How to continue from here?


If $f(x)=x-\int^{\frac{\pi}{2}}_0f(x)\sin(x)dx$ find the explicit function for $f(x)$ in its simplest form

A function $f(x)$, where $x$ is a real number , is defined implicitly by the following formula:   $$f(x)=x-\int^{\frac{\pi}{2}}_0f(x)\sin(x)dx$$   Find the explicit function for $f(x)$ in its simplest form.   This question appeared in the recent New Zealand Qualifications Authority 2016 Scholarship Calculus examination.    What I have done  Let $f(x)=y$  $$f(x)=x-\int^{\frac{\pi}{2}}_0f(x)\sin(x)dx \Rightarrow y=x-\int^{\frac{\pi}{2}}_0y\sin(x)dx$$  $$ y=x-\int^{\frac{\pi}{2}}_0y\sin(x)dx  \Leftrightarrow \int^{\frac{\pi}{2}}_0y\sin(x)dx=x-y$$  Consider the integral  $$ \int^{\frac{\pi}{2}}_0y\sin(x)dx$$  Let $u=y\Rightarrow du=dy$ and $dv= \sin(x) \Rightarrow v=-\cos(x)$  $$ \int^{\frac{\pi}{2}}_0y\sin(x)dx = \left[y\sin(x) \right]^{\frac{\pi}{2}}_0+\int^{\frac{\pi}{2}}_0\cos(x) dydx$$   How can I continue?


This question led to a new package:      This is a followup to . The idea is to switch between two different margin sizes. The answer provided by @godbyk work very well. However, it is difficult if you are using an asymmetric page layout (e.g. \documentclass[twoside]{article} and the fullwidth environment spans over two pages. Is it possible to make it work in these cases, too?   The memoir manual states:       Note that the adjustwidth environment applies to complete paragraphs;   you can’t change the width of part of a paragraph except for hanging   paragraphs or more esoterically via \parshape. Further, if the   adjusted paragraph crosses a page boundary the margin changes are   constant; a paragraph that is, say, wider at the right on the first   page will also be wider at the right as it continues onto the   following page.   So, how to do it esoterically ;)  MWE:  \documentclass[twoside]{article}  \usepackage{changepage}% provides the adjustwidth environment  % The following code should be used *after* any changes to the margins and % page layout are made (e.g., after the geometry package has been loaded). \newlength{\fullwidthlen} \setlength{\fullwidthlen}{\marginparwidth} \addtolength{\fullwidthlen}{\marginparsep}  \newenvironment{fullwidth}{%   \begin{adjustwidth*}{}{-\fullwidthlen}% }{%   \end{adjustwidth*}% }  \usepackage{lipsum}% provides dummy text  \begin{document}  \lipsum[1]  \begin{fullwidth}     \lipsum[2-10] \end{fullwidth}  \lipsum[3]  \end{document}


I'm trying to install node.js version 12 on my Ubuntu 19.10 laptop by following the instructions .  When I execute the curl command I get an error about a locked directory:  $ curl -sL https://deb.nodesource.com/setup_12.x | bash -  ## Installing the NodeSource Node.js 12.x repo...   ## Populating apt-get cache...  + apt-get update Reading package lists... Done E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied) E: Unable to lock directory /var/lib/apt/lists/ W: Problem unlinking the file /var/cache/apt/pkgcache.bin - RemoveCaches (13: Permission denied) W: Problem unlinking the file /var/cache/apt/srcpkgcache.bin - RemoveCaches (13: Permission denied) Error executing command, exiting   I've looked to see if there's an apt-get task and rebooted my machine, but no joy.    Does anyone have a suggestion on how to get past this?


"click on the image" vs. "click the image"

Transitive verbs take object directly. Source -     If "click" is a transitive verb, why do we say "click on the image" and not "click the image"?


Rakan and Xayah have the ability to recall together where one starts recall and the other can join in. Will the 2nd champ who joins in at the last second get recalled to base instantly, or does the recall refresh?


I am using blender 2.79b. I cannot see the image output even after i load an image. I used the properties panel to load the image. Under the 'Background Images' tab. I added an image file(i tried both ".png" & ".jpg" formats). Please guide me.


geodesic computation: "energy" minimization versus arc length minimization

Is it true that applying the Euler-Lagrange equation to the integral  $E(\gamma)=\int_{t_1}^{t_2} g_{\alpha\beta}(\gamma^{\alpha})'(\gamma^{\beta})'\operatorname{d}\!t$ rather than the arc length integral $L(\gamma)=\int_{t_1}^{t_2} \sqrt{g_{\alpha\beta}(\gamma^{\alpha})'(\gamma^{\beta})'}\operatorname{d}\!t$ is just a mathematical trick for simplifying computation when parameterizing by arc length?  Isn't it true that if you are parameterizing a curve on a surface by something other than a constant multiple of arc length (for example, a curve $\mathbf{C}(x)=(x,y(x))$ in the parameter space of the hemisphere surface mapping $z=\sqrt{1-x^2-y^2}$), the critical point of $E(\mathbf{C})$ will not be a geodesic in general?


An application attempted to save a file with a ':' in it, now the file is not deletable

I used an application that creates files automatically which attempted to save a file with a ':' character on it on a Windows 10 system.  The colon is clearly not an allowed character - but somehow the application succeeded in creating a file of size zero bytes, with the name truncated from the colon onwards.  For example, if the file was named "My File : A history", the zero-byte file that was created was called "My File ".  I have three such files and am unable to delete them.  Using file explorer, I get a message box that says "This is no longer located in .  Verify the item's location and try again."  Using the command prompt to try and 'del' the file, I get an error that states "Could not find "  I get the same errors when moving them.  The files aren't causing any issues, but I'd like to delete them rather than have these be permanent fixtures of this directory.


Is it considered rude if you only ask Questions but almost never answer one yourself

I have used the websites of SO a lot the past few months because I am busy with a large scale web project. I feel I get better answers here on SO than when I just do a Google search, maybe because I can be more specific here with my problem, and the responses are really fast.  Occasionally when I am not working I try to answer some questions, but the question almost always has an answer which is 'as good as' or 'better' than the answer I would supply.  So my question/answer ratio is about 20/1 something, if not more. When I look at my profile page I see a bucket-load of questions and almost nothing I answered myself.  Is this considered bad behaviour? I can see that this looks a little egoistic.  : One devoted to one's own interests and advancement.


I road in a book that the function $f(x)=\sqrt{x} \sin(x)$ is differentiable at 0. Personally, I don't think so since f is undefined on the left of $x=0$. Can you confirm my thought or the book?


How to cite a work in a manuscript that is under review?

I have two manuscripts that I am ready to submit in two different journals.   In the first manuscript, I have developed two models to be used for my research. Both of them are new and are an upgrade to the currently used models.  In the second manuscript, I have used one of the models developed in the first manuscript and have carried out an elaborate study. However, I am unsure on how to cite the first manuscript in the second.   Can I cite a submitted manuscript as "under review" in another manuscript? What's the correct procedure for citing under review works?


directory size inconsistent between "du *" and "du file"

Can someone help me understanding this ?  # du -hs * 3,8M    depmodwrapper-cross 712M    linux-karo 211M    u-boot-karo  # du --apparent-size -hs * 3,6M    depmodwrapper-cross 672M    linux-karo 176M    u-boot-karo  # du -hs u-boot-karo 584M    u-boot-karo  # du --apparent-size -hs u-boot-karo/ 524M    u-boot-karo/   There are more info about filesystem and number of files  # df -h . /dev/md3        822G  658G  123G  85% /mnt/tmp  # mount |grep /mnt/tmp /dev/md3 on /mnt/tmp type ext4 (rw,relatime,data=ordered)  # find u-boot-karo/ |wc -l 28392   Forced e2fsck do not fix this. What does this mean ?


How does the List interface store data in java?

i've been wondering how does the interface List in java store data. An interface is a set of methods that must be implemented by a class (please correct if i'm wrong) and thus a list can't have variables to store data. For instance, List<Integer> list1 = new ArrayList<>(); list1.add(5); where will the integer 5 be stored ? Does the list1 use the ArrayList's attributes  to store data ? What really happens when i create an interface ? Does it create an object of a certain class to operate on it ? Thank you


Can we say:  His mother forbade his going out at midnight.  In some countries, women's wearing tiny skirts is totally forbidden!  But I don't mind (my) smoking here. here can we add "my"?  Somebody told me forbid+act so we can't say like that is that true?  Thanks very much!


Dn denotes the squares of a 2-by-n board using plain dominos. Then we see D1 = 1, D2= 2, and D3 = 3. find more values of Dn and guess an expression.

I understand this problem that this sequence is a Fibonacci sequence. Also, Fibonacci series is f(n) = f(n-1) + f(n-2). However, I am stuck on how to prove this using strong induction.   I am at this step: Dk+1 = Dk + Dk-1. I do not where to go from here. Any help would be appreciated.


How to fix NullPointerException in breath first search in java?

I try to construct a breath first search relationship(BFS) by using a txt file. It works perfectly when the BFS size is small(eg. 7nodes), but NullPointerException appears when the BFS size is big(eg. 20000nodes). I've already read some posts about NullPointerException, but I still have no idea on how to solve it.    The exception message:  Exception in thread "main" java.lang.NullPointerException         at GraphAdjacentList.setEdge(GraphAdjacentList.java:16)             at GraphAdjacentListDemo.main(GraphAdjacentDemo.java:52)   There are 7 nodes, then each line shows the relationship of two nodes. The format of the txt file:  7 1 2 1 3 1 4 4 5 4 6 5 7   My code:  import java.util.*; import java.io.*;  public class GraphAdjacentListDemo{ /* to build an adjacentList */ final private Map<Integer, List<Integer>> Adjacent_List; public GraphAdjacentListDemo(int numberOfVertices){     Adjacent_List = new HashMap<Integer,List<Integer>>();     for(int i=1;i<=numberOfVertices;i++){         Adjacent_List.put(i,new LinkedList<Integer>());     } }  public void setEdge(int source,int destination){     List<Integer> sList = Adjacent_List.get(source);     sList.add(destination);     List<Integer> dList = Adjacent_List.get(destination);     dList.add(source); }  public List<Integer> getEdge(int source){     return Adjacent_List.get(source); }  public static void main(String args[]) throws Exception{     /* to import a node source file */     File f = new File("/Users/apple/Desktop/Graph_Sample.txt");     List<Integer> source = new ArrayList<Integer>();     int count=0;     Scanner sc = new Scanner(f);       while(sc.hasNextInt()){         int i=0;         i = sc.nextInt();            source.add(i);         count++;         }         sc.close();      /* to store nodes into source_array and destination_array */     int time=(count-1)/2;     List<Integer> sourceList = new ArrayList<Integer>();     List<Integer> destinationList = new ArrayList<Integer>();     for(int i=1;i<=time;i++){         sourceList.add(source.get(1+2*(i-1)));         destinationList.add(source.get(2+2*(i-1)));     }      GraphAdjacentList adjacentList = new GraphAdjacentList(source.get(0));     for(int i=0;i<sourceList.size();i++){         adjacentList.setEdge(sourceList.get(i),destinationList.get(i));                  }      System.out.println("The graph is:\n");     try{     for(int i=1;i<=source.get(0);i++){         System.out.print(i+"-->");         List<Integer> edgeList = adjacentList.getEdge(i);         for(int j=1;;j++){             if(j != edgeList.size()){                 System.out.print(edgeList.get(j-1)+"-->");             }else{                 System.out.print(edgeList.get(j-1));                 break;             }         }         System.out.println();         }     }catch(InputMismatchException inputMismatch){}   }  }


Let $A$, $B$ and $C$ be complex matrices such that $C\neq 0, $ $AC=CB$. Prove that $A$ and $B$ have a common eigenvalue.   There is a hint in the question, these facts can be used for the prove:   For a complex matrices $A, B$, If $AB = 0$, and $B$ is invertible, $A = 0$. For a complex matrices $A, B$ and $C$, if $AB = BC$ than for each natural number $k$, $\\\\A^kB = BC^k $.   Any ideas?


If $f^2(b) - f^2(a) = b^2 - a^2$, then the equation $f'(x)f(x) = x$ has at least one root in (a, b).

Suppose $f$ is continuous on [a, b] and differentiable on the open  interval (a, b). How to  that if $f^2(b) - f^2(a) = b^2 - a^2$,   then the equation   $f'(x)f(x) = x$   has at least one root in (a, b).


Reasons for limits in triple integral of sphere

I know that the volume of a sphere is given by the triple integral $ \int_0^{2\pi} \int_0^{\pi} \int_0^r \rho ^2 \sin \phi d\rho d\phi d\theta $.   I am having trouble on how the limits for the angles are derived. Why don't they both go up to $2\pi$. Please help.


Is this an appropriate place to call for the resignation of an SO employee?

In a completely hypothetical situation wherein a known employee of Stack Overflow takes public actions that are objectively detrimental to both the company and community, and for which actions shows no remorse and makes no attempt at amends, apology, or  restitution:   Is this the appropriate forum to express the completely hypothetical opinion that the employee in question should resign their position for the benefit of the community?    I realize that this question may come across as trolling or gaslighting given the current... climate of Meta, but I'm not terribly familiar with the rules of Meta and I'm genuinely curious as to whether such a post would be in violation of any standing policies.  Please note that I'm not calling for anyone's resignation here (nor am I advocating such); I'm simply wondering how such a question would be received and whether it would be closed.


Intersecting geodesics in a positive curvature manifold

Suppose $M$ is a connected, compact orientable 2-dimensional Riemannian manifold, with positive Gaussian curvature. I'd like to show that two non-self-intersecting closed geodesics must intersect each other.  I tried to use Gauss-Bonnet Theorem to prove this, but I wasn't successful. Can somebody help me ? Thank you.


$f$ is entire, satisfying    $$|f(z)|\le \frac1{|\text{Re}(z)|}.$$   Show that $f$ is identically zero.    It suffices to show boundedness. Since $f$ is bounded on the real line, then if $f$ is unbounded on the complex plane, the infinity must be an essential singularity, which means, for an arbitrarily chosen point $z_0\in\Bbb C$, we can pick a sequence $z_n$ whose moduluses tend to infinity with $f(z_n)\to z_0$, and it follows that $|z_0|\le \frac1{|\text{Re}(z_n)|}$. This is the best I can do.   I'm not sure if I'm going in the correct direction. It however seems unlikely for me to deal with the problem on the $y$-strip in this way.


Is it a runout if both the batsmen have reached the same end and at the same end the stump is broken?

The situation is as below:  -------|----------------------------        |  stump |batsmen2   broken|batsmen1  here  |  -------|----------------------------   Is it a runout in the above situation?


When we apply a force, there's always a reaction force too. Why do forces always come in pairs?


I am using a modified verbose-ibid citestyle (as suggested ). If I use \cite, it won't use the short version, and that might be good, but right know I need to use the short version (cite:short). So how would I use \cite and force the short form?


Detect beginning of a sentence in a macro for capitalization

Is it possible to make macros give different results at the beginning of a new sentence? Suppose that I want the macro "\secname" to write "Section" at the beginning of a new sentence, and "section" anywhere else. How can I do so?


How can a 13 year old kid like me learn quantum mechanics and other advanced physics topics?

I have a huge interest in learning quantum mechanics and other advanced physics topics. Also I need to learn the mathematics for physics as well such as linear algebra and calculus. So please could you guys tell me some resources or books which do not dumb down content, but are appropriate for absolute beginners like me. Also may I please get resources or books for QED and QFT, and other advanced physics topics. Thank you.


Query runs in serial and parallel mode in two identical databases on the same instance

I have two databases in the same SQL Server instance. One is a test database with a smaller number of records and total size of 500GB. Other one is production database with a size of 2.2 TB. Both database are similar with same database objects. The server is enabled for parallel execution with MAXDOP = 8 and Cost Threshold for Parallelism = 20. There are 40 logical CPUs on SQL Server 2016 Standard edition.  When I run a somewhat complex query that has multiple joins and views, on the production database the query executes fast in parallel mode.  When I run the same query in the test database (on the same instance) the query runs in serial mode. Data in test database is static too.  I do not understand why it is not running in parallel mode.  From my research, since the test database is small compared to the production database, maybe the cost of the query in the test db does not exceed 20 (cost threshold for parallelism). How can I calculate the cost of the query to confirm?  I made the query run in parallel by removing a scalar function and replacing it with an inline function, but the same query runs differently in two identical databases, that is why I am confused. I have gone through the post which explains why SQL Server does not engage parallelism.  Estimated Subtree Cost is different in both. The one running in serial has a low value of 44. The parallel one has a higher value of 312.  Since the parallel one has to deal with more data, its individual node subtree cost is higher and adds up to 312. So maybe cost is the real issue?  My cost threshold for parallelism is 20 and the one running in serial has an estimated subtree cost of 44 (> 20). So shouldn't it run in parallel?


I have a website where we created a unique and informational content and now we want to target same content City wise. So I don't have much to change as just changed the city name for other pages. So will google count it a duplicate content? As it's mine content so should not be the case. And also it's highly relevant on the page so won't impact the page experience and information is highly relevant on the page? Will google count this as a good practice? Do I need to make any SEO changes here?


I have some text parented to the camera to show how many lives the player has.  In the viewport, it looks like this:  But in the game, it looks like this:   How can I fix this?  Thank you.


In a 2D multiplayer game should I send the position of user to the server all the time?

In a 2D game where the user moves with the keyboard arrows, should the user send all the time he moves his position (x, y)?. If the user has some speed, the user would send (x, y) like 50 times pixel by pixel in just a second.


I am working on a campaign and there is a very good chance that the PC’s may find themselves involved in a large mass battle, a large siege or possibly both if things go slightly sideways in regards to there actions and success through the campaign (of course they may just as equally decide to get out of dodge if it all goes sideways but that is the joy of running a free from open campaign). I have experience of a system for large battles from 1st edition legend of the 5 rings, a combination of the players attempting to complete heroic actions to sway the battle, combined with dice rolling the skill of the generals behind the scenes to gauge the flow of the battle. Are there any official published 5th edition rules or suggestions as to how to run these kind of large scale battles for D&D?


How to import a default package class inside a workfolder package?

This is the directory structure of my program - Global Folder --base ---x ---y ---z --demo ---t ---u ---v -graphics.java -driver.java  x y z t u v are simply .java files. I have classes derived from base classes in demo, imported with a simple import demo.* How can I access a public method in graphics.java from a class in demo package?


Gödel's (in)completeness theorems and the axiomatization of Euclidean geometry

In David Hilbert's 1899 Grundlagen der Geometrie, Hilbert gives a rigorous axiomatization of Euclidean geometry. As I understand it, some of Hilbert's axioms must be expressed in second order logic (for example his "Euclid's axiom") and as his system contains some notion of arithmetic (this is perhaps not correct?), by Gödel's first incompleteness theorem this means that Hilbert's axiomatic system is incomplete (meaning that there exist statements expressed by the vocabulary of the system that cannot be proven to be true) and by Gödel's second incompleteness theorem, his system cannot demonstrate its own consistency.  Later, Tarski gave his own axiomatization of Euclidean geometry that is entirely in first order logic so by Gödel's completeness theorem, it can demonstrate its consistency, it is decidable and complete.   Is the above accurate and if so, is Tarski's axiomatic system still inferior in some ways to Hilbert's (with a lack of expressive power or doesn't cover the entire Euclidean geometry as we understand it)?


Reference for Fredholm Integral Equations..

Can anyone recommend me some nice books about ? I'm looking for complete references.


How could you password protect an application

How would you create A pop-up password dialogue using zenity (or other application) so that when a user tries to access a specified Applictaion it asks for a password


What material can help a tester generate more and better ideas?

which domain knowledge other than software engineering can help a tester generate good test ideas?  any books , courses, philosophy, theories , puzzles etc.


Is it possible to get single SIM card for Vienna + Prague without roaming

I will be travelling between Vienna and Prague in December. My plan is to buy local SIM card but as Vienna/Prague are very near to each other, i was wondering if any mobile operators offer combined plans for both cities.  Any ideas on this?


How to include PDF pages without a newpage before the first page?

I am using pdfpages which works quite well.  But this time, I want to include a 5 page pdf and the first page should be scaled down a bit such that above the first page is enough space for a subsection (in the LaTeX document).  Using just  \usepackage{pdfpages} ...  \subsection{Interesting Letter} \includepdf{letter.pdf}   does not work, because includepdf inserts a newpage command before the first page.  I looked at the pdfpages manual but could not find options relating to that.  I hacked this command, which kind of works:  \newcommand{\insertrep}[1]{% \hspace*{-2.4cm} \fbox{\includegraphics[page=1,scale=0.8]{#1}} \includepdf[scale=0.8,pages=2-,frame]{#1} }  \subsection{Interesting Letter} \insertrep{letter.pdf}   The subsection is printed on the same page as the first page of the pdf, but an empty page is inserted before the section ...  The empty page vanishes if I scale the first page to 0.5 - which is too small ...  It seems that \includegraphics inserts an empty page before the graphic, if the inserted graphic violates the margins of the page.  Besides, the hspace value does not always fit.  Thus, my question: How to solve this right?


Does the arithmetic mean minimize the sum of absolute values of deviations?

We have $x_1,x_2,\ldots,x_n \in \mathbb{R}$. I conjecture there to be a number $M \in  \mathbb{R}$ such that  for any $i=1,2,\ldots,n$ the quantity $$|x_i - M|$$ is as small as possible. How do you go about proving that $M$ is the arithmetic mean $$M=\frac{\sum_{i=1}^{n} x_i }{n}\text{ ?}$$


How should I approach for creating a command-line parser in java?

Hi I want to create my own command-line parser using java. As you might know, the design of this parser can be in a lot of ways.   I found this  but this seems more complex than I hoped.   I have more simple questions like;   What kind of data structures can i use to store options and parameters?    When I capture the commands, how should I execute them?   Can you give me something more in the starting stage. Can be a class design approach or some little library that you know.


Where is the downloaded package files directory?

Where can I find the location of downloaded .deb files?  I want to copy this folder before I reinstall Ubuntu so I don't have to redownload the packages.  I am running Ubuntu 12.10 32-bit.  How can I do this?


How many strings of length $n$ with $m$ ones have no more than $k$ consecutive ones?

Here is a problem from generatingfunctionology that I'm stuck on:    I'm trying to get started on part (a). I broke the string up like this. If the last digit is $0$, the number of possible strings is then $f(n-1,m,k)$. If the last digit is $1$, there are two subcases. If the $n-1^{th}$ digit is $0$, then we can cut them both off and the number of strings is $f(n-2,m-1,k)$. However, if the $n-1^{th}$ digit is $1$, then I don't know what to say, since even if I cut both last $1$s off, I can't have the last $k-2$ numbers of my $n-2$ long string be $1$s, but it's entirely possible that I could have $k-2$ $1$s earlier in the string. So I have something like: $$ f(n,m,k)=f(n-1,m,k)+f(n-2,m-1,k)+??? $$ and I don't know what third term to put there. What is the third term? Thanks.  If it's not trouble, I may ask questions on parts (b) and (c) when I get there.


When I try to install Pycharm or Atom through Ubuntu software centre, I get the error: snapd returned status code 400: Bad Request

I've just tried installing atom and pycharm from the software center.  Here's what happened:  I was asked to register to Ubuntu One. I was asked for authentication. Once the authentication was done,  I typed in my system password. I get this:   Detailed errors from the package manager follow:   snapd returned status code 400: Bad Request  Then I tried installing multiple software. Many of them like pycharm and atom were giving the same error.


Does paralysis prevent actions that don’t require movement?

Looking at the D&D 5th edition Compendium , I see:     A paralyzed creature is incapacitated (see the condition) and can’t   move or speak.   And for incapacitation:     An incapacitated creature can’t take actions or reactions.   Compare this to the , which specifically mentions physical actions:      This special attack renders the victim immobile. Paralyzed creatures   cannot move, speak, or take any physical actions. The creature is   rooted to the spot, frozen and helpless. Not even friends can move his   limbs. He may take purely mental actions, such as casting a spell with   no components.   Does this mean that, counterintuitively, by rules as written in 5th Edition a paralyzed creature cannot take actions that don’t require movement (e.g. casting a spell with no components)? It seems a silly interpretation, but that’s what the rules seem to be saying (assuming this resource accurately reproduces the rules).


How can I find the value of the following sum? $$\sum_{n=0}^{\infty}\arctan(\frac{1}{F_{2n+1}})$$ $F_n$ is the Fibonacci number.($F_1=F_2=1$)


Is there a way to change the Window 10 virtual desktop name

In Windows 10 there are virtual desktops. Unfortunately, the are by default Desktop 1, Desktop 2, etc. Or as in my screenshot Bureaublad 1, Bureaublad 2. Is there a way to rename them to something more useful?


What resolution would be needed for a billboard advertisement?

Does anyone know the required resolution for a photograph to be used on a billboard?  Would the Canon 7D be able to provide a large enough file size to meet the requirements?


Closure of an open ball is equal to the closed ball (Euclidean space)

Consider the Metric space $(\mathbb{R}^n,\|\cdot\|)$. Show that $Cl(B(x,r))=C(x,r)$ with $C(x,r)$ the closed ball around $x\in X$ with radius $r$.   $\operatorname{Cl}(B(x,r))\subseteq C(x,r)$ is trivially true (the closure is the smallest closed set containing $B(x,r)$).   I, however, have difficulties proving it the other way around. I am able to prove it when I introduce the concept of a boundary point and show that $\operatorname{Cl}(B(x,r))=B(x,r) \cup \partial(B(x,r))$, but the concept of a boundary hasn't been introduced yet in the lectures. Can anyone give me a hint on how to prove this without using the concept of a boundary?     Definition: Let $x\in X$. We say $x$ is a closure point of $A\subseteq X$ when $\forall r>0$ $B(x,r)\cap A\neq\emptyset$. We denote the set of all closure points as $\operatorname{Cl}(A)$


Is a relational database with a dynamic number of tables a good design?

I have a use case where I wish to create a table for each entity to which the underlying application that owns this entity will publish records. This table has a fixed structure, so if there are 5 such entities in my system, there will be 5 different tables with the same schema. The schema is generic with one of the columns in the schema as JSON for flexibility. I do not expect queries based on the fields in the JSON. I expect the following queries on each entity:  On the auto-increment id primary key column with LIMIT and OFFSET where I need to read X rows from the record with id Y. On the creation date column with LIMIT X.  I expect thousands of such entities to be created on the fly so in turn there will be thousands of tables in the database. In future when one of these entities have fulfilled their purpose, the table would be simply deleted. I expect most of these tables to have not more than 100 rows while there will be a few with at least 1M rows as time goes by. This design makes data easy to query as my application can determine the table name from the entity name. Is this a bad design? Is there a limit to the number of tables in a database in RDBMS (the above design is with Postgresql 11 in mind) keeping performance in mind? Should I use any different datastore to achieve this other than RDBMS? Any suggestions?


Force quit from running thread in Python

I'm trying to force quit all running threads and do clean up when people press Ctrl+C.  I followed this , but threads only quit if they are sleeping. This is my base class:  class StoppableThread(threading.Thread):      def __init__(self, timeout):         threading.Thread.__init__(self)         self._timeout = timeout         self._stop = threading.Event()      def run(self):         while not self.stopped():             self._stop.wait(timeout=self._timeout)  # instead of sleeping             if self.stopped():                 break             self.target()      def cleanup(self):         pass      def target(self):         pass      def stop(self):         self._stop.set()         self.cleanup()      def stopped(self):         return self._stop.isSet()   Although I've called stop() method, thread still try to finish target() function before quitting. How can I force exiting from target() function?  This is minimal code to reproduce:  class TestThread(StoppableThread):     def __init__(self):         super(TestThread, self).__init__(2)  # sleep 2 seconds      def target(self):         print 'Begin `target` function'         sleep(10)  # simulate long-running task         print 'Finish `target` function'      def cleanup(self):         print 'Clean Up'   if __name__ == '__main__':     t1 = TestThread()     t1.start()     print 'Thread 1 started'      t1.stop()  # before run into `target`     t1.join()  # quit immediately      print '\n################\n'      t2 = TestThread()     t2.start()     print 'Thread 2 started'     sleep(3)      t2.stop()  # after run into `target`     t2.join()  # blocking until `target` finished


Issue keeping connected app values the same after Salesforce redeploy

I'm facing an issue when we redeploy Salesforce. The connect applications on each environments lose all of their correct settings. I'm hoping to find a way around this. My main goal is to keep the connected apps the same, with static values as they are connected to the likes AWS, so losing these settings basically breaks our setup and we have to manually fix each app. I've investigated using the developer API to refresh each connected app with the correct settings after each deployment.But the issue with that is it seems I have to manually go onto Salesforce after the app is created through the automated process and save the app for it to become exposed/available for use. I'm also looking into using DX Packaging to keep the settings static for each connected app. I haven't had much luck getting this to work yet as I haven't much Salesforce experience and our deployment process was setup by someone else. Apologies if I'm missing something obvious, I'm new to Salesforce and still becoming familiar with terminology of the technology


Two sidebars in Beamer for two presentations in one tex file

I am trying to combine two presentations into one tex file. After the title of the second one, I still get the sidebar components of the first presentation. Do you know any way to 'restart' the sidebar to reflect only the second table of contents?


$f:I \rightarrow \mathbb R$ is said to be Hölder continuous if $\exists \alpha>0$ such that $|f(x)-f(y)| \leq M|x-y|^\alpha$, $ \forall x,y \in I$, $0<\alpha\leq1$. Prove that $f$ Hölder continuous $\Rightarrow$ $f$ uniformly continuous and if $\alpha>1$, then f is constant.  In order to prove that $f$ Hölder continuous $\Rightarrow$ $f$ uniformly continuous, it is enough to note that $|f(x)-f(y)| \leq M |x-y|^\alpha \leq M|x-y|$, since $\alpha \leq 1$. This implies that f is Lipschitz $\Rightarrow$ f is uniformly continuous.  But how can I prove that if $\alpha >1$, then $f$ is constant?


Pythonic way to create list of repeated independent elements

I have created a list of hashes as follows in python:  >>> hash_obj = [{}]*3   However, updating any one of the hashes in this list updates all elements:  >>> hash_obj[0]['a'] = True >>> print(hash_obj) [{'a': True}, {'a': True}, {'a': True}   Is there a clean 'pythonic' way to create a list of repeated independent elements? I also think the behaviour here is counterintuitive and should be changed, very interested to know why developers implemented as such.


Using Mathematical Induction to prove Reversal of Strings

The problem at hand:  Recall our recursive definition of the reversal of a string over $\Sigma$.   Base case: $\epsilon^R=\epsilon$ If $w \in \Sigma^*$ and $c \in \Sigma$, then $(wc)^R =cw^R$.   Use the definition above along with mathematical induction to prove the following: If $v,w$ are strings over $\Sigma$, then $(vw)^R= w^Rv^R$.  I'm honestly stumped and don't know where to begin. I've done mathematical induction on actual numbers but not on just variables like this problem. Any help is appreciated.


Compare Java Methods without external influence

I'm trying to compare on different levels two or more methods that are supposed to do the same thing. I'd like to compare them time-wise (who's faster), memory consuming-wise, etc.. but I don't want the results to be influenced by some background activity my computer may be doing (load an internet page, check for updates, etc...).  What are my options here to test my methods in an environment free of "distractions" that could influence the results.


Distributed web server to stop DDos attacks?

I have been thinking about a way to hinder DDos (Distributed Denial of Service) attacks (which seems to be a hot topic at the moment) by placing a signed Java Applet on the web site. This Java Applet should function as a web server so people viewing a web site could utilize their bandwidth to help others access the same web site. The Java Applet should not be included on the front page, but only if you clicked on a link like: "Help us against DDos attacks". Of course the first web page to get distributed to the web server, would be the front page, and just doing this should alleviate a lot. There are a lot of issues with this, which I simply lack the knowledge to solve.   Could this be utilized to help against DDos attacks? Would it be possible to do this in such a way that one can guarantee that the content that the distributed web servers sends out is the actual content of the page?    The distributed web servers could communicate with eachother, so they could organize themselves in hierarchies according to bandwidth etc.   There would need to be a central server to decide what content to present and which servers to utilize, but maybe it could be configured on only communicate with the Java applets so it would only accept incoming connections from certain IP addresses or something like that?  I believe that lots of people would keep this page running in the background to help out vulnerable web sites.  Please help me think outside the box on this issue, because there is a web site, I would really like to help out.


Are Canon EOS and Nikon DSLR lenses interchangeable?

Can we use the lenses from, say a Canon EOS 550D kit (Canon EF-S 18-55mm) with a Nikon DSLR D5000 for example) ? Also, is the reverse possible ?  I'm looking at interchangeability between recent DSLR lenses only, and not with older lenses. Also, for "average" lenses, and not ultra wide/ultra zoom.  The reason for this question is that I'm trying to decide between a Nikon D5000 and a Canon EOS 500D. I like the Nikon better, but Canon is more popular here amongst people I can interchange lenses with :)


An integer is a $n$'th power if that holds true for all moduli.

I have not been able to solve this problem. Any insights would be appreciated!   Let $x, n > 1$ be integers. Suppose that for each $k > 1$ there exists an integer $a_{k}$ such that $x − a_k^n$ is divisible by $k$. Prove that $x = A^{n}$ for some integer $A$.


How to remove Ubuntu from a computer with a dual boot option (Ubuntu is on a separate SDD than Windows)

I've been using Ubuntu for quite some time now but I need to shift to Windows and I need the SSD which Ubuntu is taking. I have set up a dual boot option, one SSD is Windows 10 and the second is Ubuntu. I want to remove Ubuntu and be able to add that SSD to Windows 10 if that's possible without reinstalling Windows.


Does Libre Office have an equivalent of OneNote, or is there another alternative?

I know that Libre Office is a bit like Microsoft Office, but I can't find the equivalent of One Note, something that I used a lot before I moved over to Ubuntu, and I do miss the features that it had. Currently I use Evernote Web, or just nothing at all.  Does this not exist?


prove if we want that the sum of some fractions be $1$ and the denominators of one of them is $d$ then another denominators should divisible by $d$ or $d$ should be divisible to another denominators.  It seems to be easy I tried to prove it.I first tried some cases.  $1=\frac{1}{2}+\frac{1}{3}+\frac{1}{6}$  Here we can see that $6$ is divisible by $3$. Also here $6$ is divisible by $2$ .But I want to prove one of the denominators but here two of them is possible.After trying a lot I cannot found any proofs.Any hints?  update1: the numerator should be prime


Binding a keyboard shortcut to shut down

I want to bind a gesture in BetterTouchTool to the shut down menu that is invoked by pressing the power button on my MacBook Air.  It's fairly simple to bind gestures to keyboard shortcuts, so what I'm really looking for is a way to bind a keyboard shortcut to the shut down menu. You can't use the power button in BetterTouchTool, so I need to bind it to a standard keyboard shortcut such as Command+Shift+S.


Prove that for any two numbers $0 \leq a < b \leq m - 1$ it is not possible that $m|b - a$

As the title suggest im having difficulty approaching how or where to start proving this. Only thing i can derive from the given is that $m|b - a$ is equivalent to $b - a = mk$ for some k


Do players have to get priority the same number of times?

I have a question regarding priority. Do players have to get it the same numbers of time during a step? I mean, for example, it's my turn, after declaring blockers, I get priority and decide to cast a spell. My opponent passes, and I get priority again, because all of players have to pass, right? And in this scenario I would have priority one time more than my opponent. Or maybe I don't get priority again?


Problems after git installation from source

I have the following problem.  I have installed latest git version from source, but maybe I have done something  wrong, because now when I am trying to install/uninstall any stuff using apt-get I get the following message:  You might want to run `apt-get -f install' to correct these:  The following packages have unmet dependencies:  git-core: Depends: git (> 1:1.7.0.2) but it is not going to be installed  E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   Well, after sudo apt-get -f install, it proposes to install git:  The following extra packages will be installed: git   and after typing 'Y' I get another error:  dpkg: error processing /var/cache/apt/archives/git_2%3a2.3.6-1avh1~lucid1_amd64.deb (--unpack):  trying to overwrite '/etc/bash_completion.d/git', which is also in package git-core 2:2.3.6-1avh1~lucid1  Errors were encountered while processing:  /var/cache/apt/archives/git_2%3a2.3.6-1avh1~lucid1_amd64.deb  E: Sub-process /usr/bin/dpkg returned an error code (1)   How can I fix it?


What's the purpose of a dual two-pole breaker?

I have one of these breakers in my panel? What is its purpose (vs a pair of two-pole breakers)? There are other  that deal with tandem breakers but not specifically dual tandem breakers.


What's the maximum safe temperature for a HD Radeon 6870?

I'm running a passively cooled HD Radeon 6870 in my PC. While using 3D Acceleration, the temperature climbs up to 95 degrees Celsius according to SpeedFan. It seems a bit hot, but on the other hand I've seen other GPUs being specified to run up to 120 Degrees Celsius. The system is very stable, but Battlefield 3 crashes every few hours or so. On the other hand it might be the game's fault and not related to the GPU temperature at all.   Does anyone know where I can find some manufacturer specs on the maximum allowed temperature for this GPU?  Thanks,  Adrian


Naruto Shippuden episodes after The final battle

After watching the final battle between Naruto and Sasuke and the Naruto Uzumaki episode, I stopped watching the series because I thought it was over. Now i see there are about ~15 more episodes.   Are the episodes after the 479 - Naruto Uzumaki (480-500) canon? Or are these episodes some fillers after the actual plot?


Find pairs of $(x, y)$ satisfying the given equation.

Find all pairs $(x, y)$ of integers such that $$xy+\frac{x^3+y^3}{3}=2007$$  $\mathbf{Try:}$  The given expression can be simplified as $$x^3+y^3+3xy=6021$$ $$\Rightarrow (x+y-1)[(x-y)^2+(y+1)^2+(x+1)^2]=12040$$ I tried considering the divisors of $12040$ but seems to be a much tedious task. Now how to proceed further.