How to observe Newton's third law violation?

I met a statement, that  disobeys the third Newton's law.  Is this true?   Also I met some setups, where it was stated, that third law is violated. Also I met some explanations about WHY it is violated, saying that momentum is transferred to the field, like in "duplicate" question:   But my question is different. I am disputing the fact itself. Is this really true, that it is possible to observe third law violation (i.e. momentum leak) in table experiments?  For illustration suppose we have two conducting parallel horizontal plates and two perpendicular horizontal rods between them. Rods have contacts with plates, so that one end of each rod is contacting one plate and another end is contacting another. Contacts go vertical, but they are infinitesimally small and we can ignore forces, induced by them.  So, two rods are perpendicular and have current flowing through them.     Magnetic field of red rod is shown by red ellipse. It reaches blue rod in the center and since it's perpendicular to the current, it applies a force to blue rod, shown by black arrow.  Magnetic field of blue rod is not shown. But it's geometry implies that red rod falls into the center of symmetry. So, there is no magnetic field, applied to red rod.  The question is: will the momentum lack be observable here?  This setup is taken from "duplicate" question setup, where two charged particles were moving. But I am not insisting on this setup.  Please suggest ANY other setup. I have my laboratory table, have wires, batteries, have Wimshurst machine etc.   Can I observe third law violation? If "yes" then "how"?


Seeking free, publicly available GIS data for Singapore?

Are there any free, publicly available datasets for Singapore?   I've examined , ,  and the  datasets, but I'm interested in vector data of higher resolution and or any type of census information.


A synthetic geometrical proof required on a result regarding Isosceles triangles.

I need a synthetic proof on this problem without the use of trigonometry.     Question: Let $ABC$ be a triangle with $AB=AC$. If $D$ is the midpoint of $BC$, $E$ the foot of perpendicular drawn from $D$ to $AC$ and $F$ the midpoint of $DE$, prove that $AF\perp BE$.    The proof is very easy using coordinate geometry.    I'm stuck at: Since point $F$ is midpoint of $DE$, it is fixed and is not a trivial information. But I can't see a way to use this information.


Could Tom Bombadil have defeated Sauron?

There is evidence that Tom Bombadil is unaffected by the One Ring's power and he has magical ways about him that can't be explained.  It seems that Tom did not participate actively in the War of the Ring, even though he was clearly more powerful than others.  Is it possible that Tom Bombadil could have used his magic to defeat Sauron?


Equation numbering problems in AMSMath environments with \pause

I'm writing a beamer presentation, and trying (unsuccessfully) to use \pause to step through a numbered array of equations, with the equations appearing in turn, and the corresponding numbers appearing at the correct time (i.e. when the equation first appears).   edit: I have partially solved the problem, using a variant on the \alt trick described , but with some vertical wiggling.  The solution ought to be a little more elegant than the one I've proposed below, given that the end user of the document (not me) is likely to need to make changes, and is not an advanced (La)TeX-user.  \documentclass{beamer} \begin{document}   \begin{frame}     \begin{gather}        1\alt<2->{\\2\alt<3>{\\3}{}}{}     \end{gather}   \end{frame} \end{document}


Windows 8 (64-bit) System.I downloaded Ubuntu  and every thing going well and started installing it. Ubuntu is successfully installed and rebooted but then I get an error during Ubuntu's boot.The error  is:  Starting Windows didn't succeed. The reason may be changing software. To solve this problem: 1. Insert installation disc of Windows and reboot pc 2. Choose language settings and click Next 3. Use Repair If you dont own this disk contact with the administrtor. File: \ubuntu\winboot\wubildr.mbr State: 0xc000007b   Here i read for many users have the same problem that i have,I think Ubuntu is not working on Windows 8 (64-bit) System


Real analysis: Show a continuous and nonnegative function on $[a, b]$ = 0

Suppose $f$ is continuous and nonnegative on $[a, b]$, and $\int_{a}^{b}f dx=0$. Show that $f=0$ on [a,b].  My idea:   The conditions, continuous and nonnegative, remind me to use the theorem to show they are Rienman integrable. My question:    It seems that we do not need to show they are Rienman integrable, since we already know their integration.  It seems it does not help if I have already showed their Rienman integrable.  I can come up two approaches, but I am not sure whether they are right.    Suppose there is a point larger than 0, then this point must fall into one of the partitions, then its integration cannot be 0.  We take $[a,b]$ as the partition, then the difference between $U(p,f)$ and $L(p,f)$ must be less than arbitrary small positive number. Hence $\sup f$ and $\inf f$ must be 0.


Can there be a multiple dimension of time?

Multiple dimensions of space makes sense. We can understand multiple dimensions of space by lines ,planes,spaces etc. But what does a 2-D time,3-D time etc means. Visualizing time as a line makes sense ,where forward means future,backwards means past and present means the point we are in right now. But a 2-D or 3-D time would like a plane or something else. So what does it means to travel right ,left in time?


Command in .bash_profile returns outdated result

The .bash_profile file has the alias below.  ~# cat .bash_profile # other commands alias btcblock="echo $(bitcoin-cli getblockcount 2>&1)/$(wget -O - http://blockchain.info/q/getblockcount 2>/dev/null)"   But if I run the command and shortly thereafter the alias, the results showed are different, as below:  ~# echo $(bitcoin-cli getblockcount 2>&1)/$(wget -O - http://blockchain.info/q/getblockcount 2>/dev/null) 503967/534428 ~# btcblock 503839/534428   It's like the results of alias is always outdated. Any idea why it's happening ?


What is the difference between the GNU Makefile variable assignments =, ?=, := and +=?

Can anybody give a clear explanation of how variable assignment really works in Makefiles.   What is the difference between :   VARIABLE = value  VARIABLE ?= value  VARIABLE := value  VARIABLE += value   I have read the  in GNU Make's manual, but it still doesn't make sense to me.


How to install Epson L3150 inkjet printer's scanner in Ubuntu 18.04? Printer was successfully installed in Ubuntu 18.04. But scanner not detect in Gimp,Xsane.(imagescan-bundle-ubuntu-18.04-3.57.0.x64.deb(1).tar.gz)installed.


Execute commands every x seconds in Python 3

In Python 3, I have written a program that checks if it has been more than 30 seconds since the last time the commands started and executes these commands. At the same time, it checks for other commands that are executed for 10 seconds, and in addition, a condition must be true.  from datetime import datetime  lastExecute1 = datetime(1, 1, 1) lastExecute2 = datetime(1, 1, 1)  while True:     utcnow = datetime.utcnow()     if (utcnow - lastExecute1).total_seconds() >= 30:         runCommands1()         lastExecute1 = utcnow     if (utcnow - lastExecute2).total_seconds() >= 10 and someCondition:         runCommands2()         lastExecute2 = utcnow   The program works, but the processor load is high (I run on Raspberry Pi) and the processor is heated.  That's why I used a sched module (). This program also works, but with a lower processor load, and that's good.The problem is that the delay in the previous program was only a few milliseconds, and now it is half a second (the commands are run at 0:0.0, 0:30.5, 1:1.0, 1:31.5 ... instead of 0:0.0, 0:30.0, 1:0.0, 1:30.0 ...). Therefore, within 10 minutes, the delay increases for approximately 10 seconds.


Proof of "$L$ / Rad$L$ is semisimple for arbitrary Lie algebra L".

I found the following statement in Humphreys' book, 'Introduction to Lie Algebras and Representation Theory', in the first chapter, section 3.1:  "Notice that for arbitrary (Lie algebra) L, $L$ / Rad$L$ is semisimple."  And as substantiation of the statement he cites the proposition "If $I$ is a solvable ideal of a Lie algebra $L$ such that $L/I$ is solvable, then $L$ itself is solvable" which was proven earlier. I could prove the proposition that he's referring to but I could not, after hours of trying, see how the statement follows from the proposition. I'd much appreciate some help on this.


How to change path in Finder by entering the path manually?

It seems that by default there is no way to enter a whole path in the Finder, so instead one should traverse through all the tree to get somewhere deep in the filesystem. Is there anyway to overcome this problem? If there is no GUI for it in the Finder maybe launching it from the command line with the path? Something like:     $ finder /Library/Frameworks/Python.framework/Versions/


I have a claim:  XX,XXX CR Bounty in Federation  Where can I collect this? I have docked in a couple space ports, checked Contacts. But nothing.


I am confused at whether or not there is a weak form at preposition's 'ON'. I've checked at some dictionaries at Cambridge and Oxford dictionary, they don't mention on the weak form's pronunciation. However, I, am a Japanese, checked at English-Japanese dictionaries, they mention on the weak form as /ən/.  For example, is there the difference of pronunciation between 'It goes on' and 'There is an apple on the table' in connected speech?  Does it exist?  Thanks Yuichi  *It's Edited


Why can't ISO, shutter and aperture speeds be controlled more precisely rather than sticking to a fixed scale?

Each camera supports a standardized scale of ISOs, shutter  and aperture speeds, adding or removing one stop of light at each value. Some cameras also support 1/3rd stop increments which adds a bit more of a scale.   But why can't the speeds be controlled more precisely, down to (say) a single ISO percentage (101 ISO) or a single aperture point (f/7)? It would obviously be too tedious in manual mode, but wouldn't the automatic exposure modes benefit from having more graduated controls?


How to find a object in by name in the properties?

I would like to change the color of one object in the shapefile. I have done it with every object of interest and it worked so far. But this one I can’t find by name in the properties. Is it possible to click on that shapefile with the “information button” and go directly to the properties where I can change the color? So far I couldn’t figure it out.   I am using the QGIS 2.12.3 - Lyon Version.


How to send Weekly Email to email-fields of records?

I have rejected Workflow Rules, since email alerts can't be sent at the exact same time every week. I have rejected schedulable Reports/Dashboards since emails can't be sent to email fields of records and the email content can't be customized.   What are the Apex topics I should look into, to send weekly emails (every Monday) to email-fields of records of a custom object? Can you provide me with code snippets?


What I want to prove is... A conjugacy class in  $S_n$ splits into two distinct conjugacy classes under the action of  $A_n$ if and only if its cycle type consists of distinct odd integers. Otherwise, it remains a single conjugacy class in $A_n$.  To prove this statement I proved...  • A conjugacy class in  $S_n$  consisting solely of even permutations (i.e. that is contained in  $A_n$ ) either is a single conjugacy class or is the disjoint union of two equal-sized conjugacy classes when considered under the action of  $A_n$.  • If  $\sigma \in A_n$, then the elements of the conjugacy class of $\sigma \in S_n$ (which is just all elements of the same cycle type as  $\sigma$ ) are conjugate in $A_n$ if and only if  $\sigma$ commutes with some odd permutation.  • $\sigma \in S_n$ does not commute with an odd permutation if and only if the cycle type of $\sigma$ consists of distinct odd integers.  I proved first two lemma and only if part of the third lemma. But I got problem considering if part of the third lemma.  The cycle type of $(1 2 3)$ in $A_{n}$ is $(3)$. But it commutes with $(4 5)$ since $(1 2 3)$ and $(4 5)$ are disjoint. I'm not sure that I'm confusing something or the author of  is saying something wrong. I hope somebody help me.


Patching a command with an optional argument or declared with \DeclareRobustCommand

To re-define a command to contain itself (patching in TeX parlance) you usually use \let.  by @egreg says:     Never use \let on commands defined with \DeclareRobustCommand or commands defined with \newcommand and having an optional argument.   So a natural question is what should we do in such cases?  For example, how do I re-define \bibitem to add another command after it? This:  \let\old@bibitem\bibitem \def\bibitem{\old@bibitem\it}   does not work, and \show\bibitem shows why:  > \bibitem=macro: ->\@ifnextchar [\@lbibitem \@bibitem .   What should I do to achieve the effect?  I would prefer not to use packages such as xpatch because I am modifying a class which others will use, and I try to use as few pacages as possible to minimize possible conflicts.


Is it OK to re-submit my own work to the same class that I am retaking?

I'm retaking a class because I flunked the final which was worth most of our grades. The papers I'm resubmitting will be slightly edited, but mostly the same as I got good grades on them. Would this be considered plagiarism?


Do I need ETA or transit visa if I have a 5 hr transit by air at Toronto airport?

I am citizen of India (Indian passport holder) with a valid F-1 visa and work permit (EAD card) with me. I have an Air Canada flight from Delhi to LA via Toronto so I have a 5 hr transit at the airport. I am not planning to go out of the airport. Do I still need a transit visa or eTA to board my flight to LA? If yes, which one do I need? I have already checked this  and doesn't specify what type of visa do I need (eTA or transit). Also, it doesn't take into account that I am a valid US Visa holder.


I have been looking at an embedded microcontroller which has a cryptographic hardware engine (in particular the ). These devices have what they advertise as a cryptographically secure PRNG, as well as a true random number generator.  The features of the random number generators are,        TRNG:         List item   Up to 25 Mbps of random bits   Multi-Ring Oscillator based design   Built in Bias Corrector       PRNG:         LSFR-based   Up to 64-bit polynomial length   Programmable polynomial   TRNG can be seed value         From what I've read about LFSR PRNG (in particular ) my understanding is that you only require 2*n bits to be able to determine the polynomial of the LFSR and hence all the random numbers that it generates.  If my understanding is correct, then only 128 bits (16 bytes) of random data are required before the random data is compromised - that is just enough for a single AES IV.  One way that I can imagine making the PRNG cryptographically secure is to reseed it after every 16 bytes using the TRNG - would this be secure?  Is it even possible to make a LFSR cryptographically secure?


Where does Deadpool fall in the X-Men timeline?

When did the events of Deadpool take place in the X-Men timeline?  Surely Deadpool takes place in a quite recent time era as compared to First Class and it's sequel, but exactly where?


Is it "is" or "are" in "There is/are two of us here"?

I have a question, which one of these sentences would be grammatically correct, or can they both be?         There is two of us here.      Or,        There are two of us here.


iam about to blow up: i cant figure out why my jobs in the crontab -e file of any user are not running. None of them do so the "last cron job is not running" problem is not aplicable. Also i checked  thread and couldn't find any mistakes. I even escaped my percent signs.  Here's my crontab -e file when running under the root user:  # Edit this file to introduce tasks to be run by cron. # # Each task to run has to be defined through a single line # indicating with different fields when the task will be run # and what command to run for the task # # To define the time you can provide concrete values for # minute (m), hour (h), day of month (dom), month (mon), # and day of week (dow) or use '*' in these fields (for 'any').# # Notice that tasks will be started based on the cron's system # daemon's notion of time and timezones. # # Output of the crontab jobs (including errors) is sent through # email to the user the crontab file belongs to (unless redirected). # # For example, you can run a backup of all your user accounts # at 5 a.m every week with: # 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/ # # For more information see the manual pages of crontab(5) and cron(8) # # Minute Stunde TagIMonat Monat TagIWoche Kommando # m h  dom mon dow   command 50 3 * */2 * /usr/bin/openssl pkcs12 -export -out /home/user/export.pfx -inkey /etc/letsencrypt/live/domain/privkey.pem -in /etc/letsencrypt/live/domain/chain.pem -password pass: blabla > /var/log/cron.log 51 3 * */2 * /usr/bin/sshpass -p xxx scp /home/user/export.pfx root@255.255.255.255:/path/to/file/> /var/log/cron.log 0 0 */5 * * /usr/bin/rsync -avx /var/www/nextcloud/apps /nextcloud/backup/path/nextcloud-apps_`date +"\%Y\%m\%d"`/ > /var/log/cron.log 0 0 */5 * * /usr/bin/rsync -avx /var/www/nextcloud/config/config.php /nextcloud/backup/path/nextcloud-config_`date +"\%Y\%m\%d"`/ > /var/log/cron.log 0 0 * * * /usr/bin/mysqldump --single-transaction -h localhost -u user -pPassword db > /nextcloud/backup/path/nextcloud-sqlbkp_`date + "\%Y\%m\%d"`.sql > /var/log/cron.log   Maybe someone can help me with my problem.  Thanks


"I will refuse nothing to a soul that makes a request of me in virtue of my passion" - meaning?

"I will refuse nothing to a soul that makes a request of me in virtue of my passion"  I am having trouble understanding this sentence because of the statement "in virtue of my passion" that follows immediately after "....request of me".(English is my second language). Could someone re-phrase the above sentence into an easier form to understand?  More specifically, is it  "I will refuse nothing to the soul that makes a request of (me in virtue of my passion)", or  "I will refuse nothing to the soul that makes a request of me,(in virtue of my passion)"?  Thank you


Minimal polynomial: is $\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}=1$?

I was wondering about the minimal polynomial of real number $$u=\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}$$ over field $\mathbb{Q}$.  As you can see , I worked out that $u$ is a root of monic rational polynomial $x^3+3x-4$. This is not irreducible: $$x^3+3x-4=\left(x-1\right)\left(x^2+x+4\right)$$ and the second, quadratic, factor has complex roots $\frac{-1\pm i\sqrt{15}}{2}$.  Can I claim that the minimal polynomial of $u$ over $\mathbb{Q}$ is $x-1$?  In other words: does this prove that $\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}=1$?  In case it does, how can we demonstrate $u=1$ working on the roots in a way different from how I did in the link?  Edit:  $\sqrt[3]{2-\sqrt{5}}$ is meant to be the real cube root of $2-\sqrt{5}$.


Prove $\gcd(a,b) \gcd(a,c) \gcd(b,c) \,\text{lcm} (a,b,c)^2=$ $\text{lcm}(a,b)\,\text{lcm}(a,c) \,\text{lcm}(b,c) \gcd(a,b,c)^2$

I'm trying prove $$\gcd(a,b) \gcd(a,c) \gcd(b,c) \,\text{lcm} (a,b,c)^2=\text{lcm}(a,b)\,\text{lcm}(a,c) \,\text{lcm}(b,c) \gcd(a,b,c)^2$$  It is a part of solution of another problem I try a lot to prove it but I could not be succeed.  I tried using exponent manipulation in prime factorizations but it didn't help me.


Does Stack Exchange have an Economics section?

I was wondering if there is a viable place on Stack Exchange to ask economics-related questions.  Questions I'd have in particular could be equation-based or theoretical.  I suppose the equation-based questions could possibly fit into mathematics but I haven't checked their FAQ.


I want only one Thread to be active, here is the algorithm:  def myfunction(update):     if threading.activeCount >=1:         # kill all previous threads     while true:         # some execution   while true:     t = threading.Thread(myfunction, args=([update]))     t.start()   so In here thread goes in Infinite loop in myfunction, so before starting new one i need to close previous one, please guide me


How to set n-th bit of *x to v value in C

I need to implement this method.  I have the unsigned * x, I need to set v value in the n-th bit, using bitwise operators in C.  void set_bit(unsigned * x,              unsigned n,              unsigned v){      //I need the code here, thanks for your help! }


Non progressive verbs. Was seeing, was looking good

Non progressive verbs are not used in continuous, right?  But what about, for example, sentences like:     "Gazing absently over the rooftops, it was a few seconds before Harry realised what he was seeing." (Harry Potter and the Prisoner of Azkaban),   or      "She was looking good" (Rajesh in the "Big bang theory").   Can it be concluded, that non progressive verbs actually can be used in Past Continuous?


On Stack Exchange, users may gain a certain level of reputation.  What does reputation do? How can a user gain or lose reputation?   See also   in the Help Center  - Maximum amount of votes a user can use in a day and reputation requirements to vote.  - How to get an exact overview of the actions that got you your reputation.  - A full list of all privileges granted at each reputation level on all sites.


How to detect which application execute my program in Delphi?

I want to find the executer app of my Delphi app.  For example, if a file named "a.exe" executes another file "b.exe" then "b.exe" should show "a.exe" in a message.  I wrote a Delphi program like this:  uses   ...PsApi, TlHelp32;  type   TForm1 = class(TForm)     procedure FormCreate(Sender: TObject);   private     { Private declarations }   public     { Public declarations }     function FindParentProcess(): String;   end;  var   Form1: TForm1;    //Boolean   ParentProcessFound: Boolean;    //DWORD   CurrentProcessID, ParentProcessID: DWORD;    //String   ParentProcessPath, WhichParentProcess: String;    //THandle   HandleParentProcess, HandleSnapShot: THandle;    //TProcessEntry32   EntryParentProcess: TProcessEntry32;  implementation  {$R *.dfm}  function TForm1.FindParentProcess; const   BufferSize = 4096; begin   ParentProcessFound := False;    HandleSnapShot := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);    if HandleSnapShot <> INVALID_HANDLE_VALUE then begin     EntryParentProcess.dwSize := SizeOf(EntryParentProcess);      if Process32First(HandleSnapShot, EntryParentProcess) then begin       CurrentProcessID := GetCurrentProcessId();        repeat         if EntryParentProcess.th32ProcessID = CurrentProcessID then begin           ParentProcessID := EntryParentProcess.th32ProcessID;           HandleParentProcess := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, False, ParentProcessID);            if HandleParentProcess <> 0 then begin             ParentProcessFound := True;             SetLength(ParentProcessPath, BufferSize);             GetModuleFileNameEx(HandleParentProcess, 0, PChar(ParentProcessPath), BufferSize);             CloseHandle(HandleParentProcess);           end;           break;         end;       until not Process32Next(HandleSnapShot, EntryParentProcess);     end;     CloseHandle(HandleParentProcess);   end;    if ParentProcessFound then begin     Result := ParentProcessPath;   end else begin     Result := '';   end; end;  procedure TForm1.FormCreate(Sender: TObject); begin   WhichParentProcess := FindParentProcess;    ShowMessage(WhichParentProcess); end;  end.   And I wrote a program (test.exe) which will execute my Delphi app:  #include <iostream> #include <windows.h> using namespace std;  int main() {     ShellExecute(NULL, "open", "Project1.exe", NULL, NULL, SW_NORMAL);      return 0; }   But the problem is Project1.exe shows itself (Project1.exe) instead of "test.exe".  How to detect which application run my Delphi program?


Objects behind glass shader appear black

Why is this Iris not showing? It worked previously, before I started working on the fur and particle system today and other parts of the model (a monkey model) and at the end I realised that the Iris disappeared. I haven't touched the eyeball, but now the iris doesn't show. I suspect that it has to do with the UVs, but everything is in place, I didn't tweak anything, it should work. I'm attaching a stripped down .blend (only the eyeball) and a screenshot. Can someone have a look into the file, and try to make the iris show?  I should also note, that when I open the previous file, it shows. But when I append that eyeball to the new file, it doesn't show.


Fix corrupted SD card filesystem using fsck

I'm trying to fix a corrupted sdcard vfat filesystem (used in an Android device) using fsck.  The sdcard just stopped working one day (the file browser doesn't show it and it's not visible in Android settings), I tried re-inserting it. When that didn't work I used my sdcard reader on my Linux machine. There I was able to mount and browse the filesystem, but after inserting it into Android it still didn't show up. I inserted it back to my Linux machine and the filesystem was gone (the device was recognized though). So I gave up and used cfdisk to create a new (ext4) partition. After doing that and quitting cfdisk, the previous filesystem (vfat) was recovered and the files could be browsed and viewed. I have no idea what's going on.  Current lsblk and fsck output:  > lsblk -f NAME         FSTYPE LABEL UUID                                 FSAVAIL FSUSE% MOUNTPOINT mmcblk0                                                                        ├─mmcblk0p1  vfat         6AEE-8592                                            ├─mmcblk0p2  swap         bf2ed99b-104e-4a91-8970-b392a19dccc8                [SWAP] └─mmcblk0p3  ext4         0cdff248-07ef-48aa-8c67-b9c86c6f8aa9     11G    55% / mmcblk0boot0                                                                   mmcblk0boot1                                                                   mmcblk1                                                                        └─mmcblk1p1  vfat         35B9-1806                                              > sudo fsck -av /dev/mmcblk1p1 fsck from util-linux 2.34 fsck.fat 4.1 (2017-01-24) Checking we can access the last sector of the filesystem Boot sector contents: System ID "android " Media byte 0xf0 (5.25" or 3.5" HD floppy)        512 bytes per logical sector      32768 bytes per cluster         74 reserved sectors First FAT starts at byte 37888 (sector 74)          2 FATs, 32 bit entries    1930752 bytes per FAT (= 3771 sectors) Root directory start at cluster 2 (arbitrary size) Data area starts at byte 3899392 (sector 7616)     482633 data clusters (15814918144 bytes) 16 sectors/track, 4 heads          0 hidden sectors   30896128 sectors total Reclaiming unconnected clusters. Checking free cluster summary. Free cluster summary wrong (189038 vs. really 118813)   Auto-correcting. Performing changes. /dev/mmcblk1p1: 1050 files, 363820/482633 clusters   For some reason, fsck returns with exit code 1  > echo $? 1   Repeating the fsck command produces the exact same output.  Is there anything I can do about this or is the SD card dead?


Windows 10 update on dual boot, can't boot into ubuntu

I decided to update my windows 7 install to windows 10, after which my grub was lost. So I used an ubuntu live usb with boot-repair and it found my win10 install. But I no longer have the option to boot into ubuntu. The partitiontable says its in extended space. How do I recover ubuntu? (system= x220 dualboot windows 10 + ubuntu 14.04)


What's the nice 'trick' to showing that the following expression is irrational?  $2^{1/3} + 2^{2/3}$


Can you warn your teammates that they are being surprised?

Can I warn my party members of an enemy even if they're surprised. If I can does that mean that they are not surprised?


How to propagate my display name change to the @name comments?

I changed my display name.  Now all comments still refer to my old @name.  Can this be fixed?


Is casting int pointer to float pointer legal if they have the same alignment?

Let's say that both int and float are 4-byte aligned. According to ISO C99 6.3.2.3 p.7:     A pointer to an object or incomplete type may be converted to a   pointer to a different object or incomplete type. If the resulting   pointer is not correctly aligned for the pointed-to type, the behavior   is undefined.   According to this, the following code should not invoke UB:  #include <stdio.h> #include <stdlib.h>  int main(void) {     int i = 7;     float *f = (float *) &i;     exit(0); }   I noticed that GCC is not always good at catching strict aliasing rules violation attempts but here in can correctly warn that dereferencing *f  will break will break strict-aliasing rules what is illegal according to 6.5 p. 7:     An object shall have its stored value accessed only by an lvalue expression   that has one of the following types:         a type compatible with the effective type of the object,     a qualified version of a type compatible with the effective type of     the object,     a type that is the signed or unsigned type corresponding to the     effective type of the object,     a type that is the signed or unsigned type corresponding to a     qualified version of the effective type of the object,     an aggregate or union type that includes one of the aforementioned     types among its members (including, recursively, a member of a     subaggregate or contained union), or     a character type.      $ gcc  -Wall -fstrict-aliasing -Wstrict-aliasing=2 so1.c -Wcast-align so1.c: In function ‘main’: so1.c:7:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing] so1.c:7:9: warning: unused variable ‘f’ [-Wunused-variable]   So does it mean that this code may invoke UB only when *f will be dereferenced and it's 100% correct in current shape?  EDIT:  One more thing - would this cast be also legal if float had a different size from int but alignment would still be the same for both types? I think yes because this is what C standard says but I don't understand why alignment is the most important here and not size. Why does alignment matters when converting pointers and only when dereferencing?


What is the difference between D&D and D&D Miniatures?

Are they the same game? Or is D&D Minis like an abridged toned down version of D&D 4.0? Or is it a separate rule-set entirely?


Updating profile and saving to all communities changes gravatar to identicon; asking question on meta reverts to gravatar

I'm aware , but I'm able to consistently reproduce another strange aspect of the bug on step 5:   Edit my profile on any non-beta Stack Exchange site Click Save and copy changes to all public communities   My profile on all other sites, including the meta site of the main profile that was edited, now use the Identicon image  Navigate to my main profile on another site, click Change picture, and select "Gravatar" Click Save changes just for this community   My profile on the respective meta site still uses the Identicon image  Navigate to the meta site, and simply click Ask Question   My profile on the meta site now uses the Gravatar image    In the meantime, I've opted to upload my profile image manually rather than going through gravatar. That appears to apply the change to all my networks without issues, as far as I can tell.  I thought that reporting these bizarre reproducible steps might help narrow down the cause of the bug.


Python: weird rounding behavior of math.sqrt()

Using Python 2.7.10, I have found quite by accident that 5*math.sqrt(3) and math.sqrt(5**2*3) are not the same float:  import math import decimal  print decimal.Decimal(5*math.sqrt(3)) print decimal.Decimal(math.sqrt(5**2*3)) print 5*math.sqrt(3) == math.sqrt(5**2*3)   returns   8.660254037844385521793810767121613025665283203125 8.6602540378443872981506501673720777034759521484375 False   which shows that they differ on the 15th decimal place. Intriguingly, this does not happen for numbers neighboring 5 and 3. The following code show a few pairs of numbers for which the equality fails:  for j in range(1,10+1):     for i in range(1,10+1):         a = i*math.sqrt(j)         b = math.sqrt(i**2*j)         if not(a == b):             print [i,j],   The list of problematic [i,j] pairs include: [3, 2] , [6, 2] , [9, 2] , [5, 3] , [9, 3] , [10, 3] , [3, 6] , [6, 6] , [7, 6] , [3, 8] , [6, 8] , [9, 8] , [5, 10] , [7, 10] , [10, 10]... Any ideas on why the rounding breaks, and why precisely for these pairs, and not others?


Keep 3d model facing the camera at all angles

I'm trying to keep a 3d plane facing the camera at all angles but while i have some success with this:  Vector3 gunToCam = cam.cameraPosition - getWorld.Translation; Vector3 beamRight = Vector3.Cross(torpDirection, gunToCam); beamRight.Normalize(); Vector3 beamUp = Vector3.Cross(beamRight, torpDirection); shipeffect.beamWorld = Matrix.Identity; shipeffect.beamWorld.Forward = (torpDirection) * 1f; shipeffect.beamWorld.Right = beamRight; shipeffect.beamWorld.Up = beamUp; shipeffect.beamWorld.Translation = shipeffect.beamPosition;   *Note: Logic not wrote by me i just found this rather useful  It seems to only face the camera at certain angles. For example if i place the camera behind the plane you can see it that only Roll's around the axis like this:   (imagine if you are looking from behind where you have fired from.  Any idea what to what the problem is (angles are not my specialty)  shipeffect is an object that holds this class variables: public Texture2D altBeam; public Model beam; public Matrix beamWorld; public Matrix[] gunTransforms; public Vector3 beamPosition;


In this  at 2:25, Sal (the narrator) says that $i^2$ is negative 1 and he didn't explain why.   Why is this so? What is the intuition behind it?


Topology induced from Kuratowski Closure properties

Proof:- From (c) $X\in \mathscr T$. $X\subset cl(X)[\because by (a)]$ and also we have $cl(X)\subset X$. Hence $cl(X)=X$ and $\emptyset \in \mathscr T$.   Let $\{U_i\}_{i=1}^n$ be a collection of open sets in $\mathscr T$. For each $i$ there exists $C_i$:$cl(C_i)=C_i$ and $U_i=X\setminus C_i$ then $\bigcap_{i=1}^{n}U_i=X\setminus \bigcup_{i=1}^n C_i$. We have $cl(C_i)=C_i,i=1,2,3,..,n$. By (d), we have $\bigcap_{i=1}^{n}U_i \in \mathscr T$. How do I prove arbitrary union axiom? If there is an axiom $\bigcap_{\alpha \in \Lambda}cl(A_\alpha)=cl(\bigcap_{\alpha \in \Lambda}A_\alpha)$. I could prove. Can you please help me?


Example of a k-dimensional random vector X where each component of the vector is normally distributed but X is not

From the , we know that if a k-dimensional random vector X = (X1, X2, ..., Xk) is (multi-variate) normally distributed if every linear combination of its components is normally distributed. This  that every component of X is also normally distributed. What about the reverse? What is an example of k-dimensional random vector X where each of X1, X2, ..., Xk are normally distributed but X is not? If there is a good example in 2-d, that would be even better, because I could plot the probability density in 3-D and visualize to improve my intuition. Motivation for this question: I have been studying professor Andrew Ng's  where we model a dataset using multi-variate normal distribution to detect anomalies / outliers. So, I am trying to understand when is it "ok" to model the data this way. For the univariate case, I can plot the data, and see if it "generally" follows a bell curve. But it's hard to get an understanding of a multi-dimensional dataset.


Why do I want to say "the iPhone" instead of just "iPhone"?

Apple is somewhat notorious for omitting articles when talking about their products, and statements such as "People love iPhone" hit my ear a little strangely. But when I stopped to think about it, I realized that I wouldn't say "the Windows" or "the iWork".   I couldn't come up with a reason that I use the definite article before some product names and not others. Is there some sort of convention (probably not a hard-and-fast rule) for usage here?


Dynamically Add remove rows with custom lookup in lightning component

I have to add row dynamically and i have to use Custom lookup comp in  first column.On the basis of lookup other fields values will be rendered in first row. But I am not able to add new row with blank values. I have followed blogs related to dynamically add/remove rows but nothing is helpfull in my case. Any help is appreciated.


In .NET the object type declares a method named GetHashCode() described here:  The article is full of gotchas about where not to use it. And my question isn't really about that. I understand that an Int32 hash code is a destructive algorithm that will quickly run into collisions with a large data set. And furthermore the calculation can change from platform to platform (and in some runtimes from process to process). I assume it is a core part of .NET since it is a member of the object class. What is this method used for? What would break if it went away? Why does it return an Int32 instead of an Int64?


I'm talking of the kind of yeast that tastes like cheese. I live in a country where finding or importing nutritional yeast is not an opcion, so I would like to know how to prepare it. I want to eat vegan & inspire people to do as well.  I haven't found the recipe or preparation anywhere.


I have a conundrum. I have a multiclassed 6th Paladin/ 5th Warlock character. With 6 levels of paladin, I have 4/2 spell slots, and as a 5th warlock, I have 2 spells that are cast as a 3rd level slot. The character has the Fiend pact, and therefore I have chosen Fireball as one of the spells in my narrow Warlock spell list.   Under the multiclass section, (and I'm paraphrasing here, without a PHB in hand), that spellcasters can share their spell slots with pact magic, and vice versa. Warlocks are not on the multiclassed caster table.   So, that being said, RAW should mean that I can burn a 1st level Paladin slot to cast a Fireball from my Warlock side, since all spells cast from a 5th level Warlock is done at its highest caster level. That means that I should literally be able to cast eight 8d6 fireballs before a long rest.   I've searched high and low to prove my theory wrong, but I think I'm correct. It seems unbalanced, and if I abuse it, no doubt my DM would intervene.  What do you all think, is my logic sound? Is there errata on this loophole?


How to install LINE (messaging app) on Ubuntu

I would like to install  chat platform on my Ubuntu 12.04 LTS system. Please, could anyone provide me the steps to successfully install this software?. I've been trying to install this software using wine but I couldn't succeed it.


I am searching a way to catch an NullPointerException in a Runnable class. I have this method called by run :  private void cooccurrence(int contextIndex, int targetIndex) {         try {             Double old_value = X.get(contextIndex, targetIndex);             X.set(contextIndex, targetIndex, old_value + 1);         }catch (NullPointerException e) {             X.growData(X.nz_length + 1);             X.addItem(contextIndex, targetIndex,  1);         } }   and I have this code in another class which call a class ThreadForX implements Runnable :  final BlockingQueue<JSONObject> queue = new ArrayBlockingQueue<>(5000000); int json_object_in_queue = 0;  ExecutorService pool = Executors.newFixedThreadPool(2);  DMatrixSparseTriplet X = new DMatrixSparseTriplet(200000,200000,0);  JSONObject inQueue_jsonObject; while ((inQueue_jsonObject = queue.poll()) != null) {         Runnable readTweet = new ThreadForX(contextLenght, inQueue_jsonObject, X, final_vocabulary);         pool.execute(readTweet); } pool.shutdown(); while (!pool.isTerminated()) { }   As you can see, the NullPointerException is really important to add an item so I need the values of contextIndex and targetIndex


Can the product of two non invertible elements in a ring be invertible?

Let $A$ be a unitary ring. The question is simply: can the product of two non invertible elements in $A$ be invertible?  I proved that the answer is negative if $A$ does not have zero divisors, because if you have $a,b$ non invertible elements in $A$ and $abx=xab=1$, then $a(bx)=1$ so $a$ is right invertible and if we put $d=bxa  \implies db=b(xab)=b1=b  \implies d=1$ (because obviously $b$ is not $0$), so $a$ is left invertible, as desired. If $A$ does have zero divisors, I don't see how to adapt the proof...  Thank you!


What space does the spell Cloud of Daggers fill?

I am trying to workout what template  (PHB, p. 222) would be on a grid. The spell states:     You fill the air with spinning daggers in a cube 5 feet on each side, centered on a point you choose within range.   So does that mean it would look like this:     Or like this:    From what I've read online, there seems to be some suggestion that it is a single square (tile) though this does stack with the spell description of "a cube 5 feet on each side".  Clearing this up for my group would be great, and I am sure our DM will be pleased as his monster were nicely diced by this spell. Thanks.


Explaining Stack Exchange to non-programmers

What's the best blog post/video/tweet/whatever to explain how the Stack Exchange system works to regular people? I am trying to gauge interest for a new Stack Exchange site, but I want to explain it to people as best (and preferably) as visually as I can. Any YouTube clips breaking it down?  anyone?  Note: I am fully aware of , but mine is about Stack Exchange, not Stack Overflow.  Most people think I'm describing traditional forum software, which they know sucks. Is there some way to describe the magic of how the design of the Stack Exchange system actually produces useful results very quickly? I can describe generally that it is a Q&A site that users vote on the answers, but Stack Overflow feels like so much more. Am I perhaps thinking too big about this?


What does "sudo apt-get dist-upgrade" do?

I would like to know more about this command:  sudo apt-get dist-upgrade


When I try to print from Gimp, it only shows print to file.  It offers none of my printers.


If a function is convergent and periodic, then it is the constant function.

I have to prove that if a function f is convergent : $$ \lim\limits_{x\to +\infty} f(x) \in \mathbb{R}$$ and f is a periodic function : $$\exists T \in \mathbb{R}^{*+}, \forall x \in \mathbb{R}, f(x + T) = f(x)$$ Then f is a constant function.  Actually, this is obvious, but I can't figure out how to prove it formally ..  (I previously thought of this : , but it doen't work because I assume the periodicity hypothesis, and then I use it to prove a contradiction ..)  Thanks !


Finite group $(G, \cdot)$ and H a subgroup of G. Prove that if $x \notin H, y \notin H$ then $xy \in H$.

Given the finite group $(G, \cdot)$ with $2n$ elements, $n \in N^*$ and also H a subgroup of G with $n$ elements.   Prove that if $x \notin H, y \notin H$ then $xy \in H$.  I'm not really sure how to do this since I've barely started working with subgroups. Could I have some hints on how to approach this type of exercise? Thank you.


How can I find out what is using the hard disk?

Possible Duplicates:             Once or twice a day my computer starts writing significantly hard to the hard drive, the HD led is ON and the performance hit is noticeable. A strange observation is that the Task Viewer does not show I/O activity - even Process Explorer shows no CPU activity and no I/O bytes read or written.  Is there a way to know which application is using the hard drive and how much data is it reading or writing?


Probability of factoring keys as a function of bit length

kinda new here, I had a question pertaining to someone being able to factor one's RSA keys through the GCD. Anyways the question goes that there are two people: A and B. A makes his/her private key as $N_a = p_a\cdot q_a$ and B does the same with $N_b = p_b \cdot q_b$. I'm assuming here that both random primes are of length n bits and so I'm wondering whats the probability of the two keys sharing a common prime. I was considering that it may have something to do with the Prime number theorem but not entirely sure.


How to get rid of layer created by Make Feature Layer (Data Management)

I like to run some scripts from mxd. Very often I am using Make Feature Layer tool to facilitate queries.  Tool help says: “Creates a feature layer from an input feature class or layer file. The layer that is created by the tool is temporary and will not persist after the session ends unless the layer is saved to disk or the map document is saved”.  Question:  How to remove newly created layer without closing mxd?   Note arcpy.mapping.RemoveLayer is not working on layer created that way or maybe I am doing something wrong here


I HAVE ALREADY INSTALLED WINDOWS 8 AND WINDOWS XP ON MY c: AND d: DRIVES OF 50 GB EACH RESPECTIVELY. NOW i WANT TO INSTALL UBUNTU ON MY e: DRIVE OF CAPACITY 50 GB. HELP ME PLS WITH THE THINGS I NEED TO KNOW TO ACHIEVE THIS. TELL ME ABT THE PARTITIONING ALSO IN UBUNTU AS I DONT KNOW ABT ext4.


How to make Deep Copy of an object in Angular?

I have an entity class as fallow: export class Contact {   id: number;   firstName: string;   lastName: string;    constructor(id?, firstName?, lastName?) {     this.id = id;     this.firstName = firstName;     this.lastName = lastName;   }   }  and want to have a different copy from Contact: export class MyComponent {      contactSrc = new Contact();   contactDest = new Contact();      constructor() {       this.contactSrc.firstName = "Adam"   }      handleCopyOfObject() {     console.log("firstName for contactSrc: " + this.contactSrc.firstName);      this.contactDest = this.contactSrc;     this.contactDest.firstName = "Mohsen";      console.log("-----------result after copy -----------");     console.log("firstName for contactSrc: " + this.contactSrc.firstName);     console.log("firstName for contactDest: " + this.contactDest.firstName);   }  }  the output is: firstName for contactSrc: Adam -----------result after copy ----------- firstName for contactSrc: Mohsen firstName for contactDest: Mohsen  you can see that by changing contactDest.firstName, contactSrc.firstName also changes. how can I change contactDest.firstName without effecting the contactSrc.firstName?


I'm trying to understand this case.  Let's say I want to have a method which has a return type of List<T>.  public List<T> GetAllItems(string category) { ... }   I've been advised to use instead this header :  public IList<T> GetAllItems(string category) { ... }   Why so?  I've made some research and one answer could be flexibility meaning that the type could be changed if it's implementing the same interface. But the motivation had to do something with exposing the interface only to prevent changes (?), I didn't really understand it. So, again, why is it better to return IList instead of List?


Is there a way to access a class from another .jar file in java

So, let's say I have a jar file called "a.jar" and another jar file called "b.jar".  In the b.jar we have a class called "c.class" and in the a.jar we have a class called "getmesomething.class" with a main function.  From the "getmesomething.class" I'd like to access the "c.class" methods and stuff.  But I do not know how to access "b.jar/c.class" from the main function in "a.jar/getmesomething.class".  I hope I spelled everything right and it isn't too confusing. :-)


Avoid page break after last line in lstlisting

I have a listing as follows:  \lstdefinestyle{yamlCode} {     numbers=left,     language=Yaml,     backgroundcolor={\color{lightgray!40}},     breaklines=true,     frame=single,     columns=fixed }  [...]  \begin{lstlisting}[style=yamlCode,label=YamlList, caption=List of Maps in YAML.] persons:   - name:  Peter     email: peter@example.org   - name:  Sally     email: sally@example.org \end{lstlisting}   Now that listing might break after the last line of code, as can be seen in this screenshot:     How can I prevent the page break after the last line? At least one line should be moved to the next page as well. Just to be clear: I do want it to break pages, however, not after the last line. How can I achieve that?  PS: Are the white lines between the code lines rendering artefacts or real? When I open the PDF in Adobe Reader and zoom in, I can still see them. Not very nice.


How can I disable the mouse wheel in gnome-terminal?

Does anybody know if it's possible to disable mouse wheel up-down events in gnome-terminal? I have a rather twitchy mouse wheel, and every time it twitches it does a history lookup in my terminal. But I still want to be able to middle-click paste.


What exactly is Simple algebra of type $A_2$? I found that it has something to do with root systems, which I also don't really know what those are. Any idea?  Thanks!


Android phone and PC is hacked. How to ensure that it won't be hacked again?

My android and PC has been hacked. Apps are being manipulated. Private data is remotely fetched. Files and photos from my PC are also fetched. The apps are being manipulated in runtime as well.   I work from home. So my most important data is on phone and PC. I am a poet and a blogger. The most intimidating issue is I found changes in my drafts which I didn't make. Also some drafts are missing. I am really terrified.   My question:  Can I get back the full control and saftety to store my data privately again? There must be some solution, how to get back full control of phone and computer again? How to prevent data from theft after reset?  Thanks.


I have defined a command for absolute value using providecommand. Initially, I simply used \providecommand{\abs}[1]{\lvert#1\rvert}  That was working fine until I needed to take the absolute value of an integral, and the lines did not scale at all. To make the lines scale, I tried \providecommand{\abs}[1]{\left\lvert#1\right\rvert}  This works in the document, but my editor (overleaf) does not like it at all, and has highlighted all subsequent text in red - an error message intermittently displays saying command may only be used in math mode. Is my use OK (and should I therefore ignore the error message - can I override it?) or is there a better way of writing it? Thanks


What facts about the weak topology fail in spaces that aren't Banach?

I'm learning about the weak and weak* topologies on a normed vector space following the book of Brezis. He limits his discussion to case where $E$ is a Banach space, and my question is most simply stated as, "Why?". I can't find an example of a theorem where the completeness of $E$ is a necessary hypothesis. Most of the basic results on weak and weak* topologies proceed by applications of Hahn-Banach, which holds for a much wider class of spaces than just Banach spaces.   Are there any examples of reasonably elementary (i.e. of relevance to a first-year graduate student who does not anticipate having heavy contact with functional analysis in the future) facts about weak or weak* topologies that are true for Banach spaces but not all normed vector spaces?  EDIT: I should add that, as Yemon Choi points out, dual spaces of normed vector spaces are complete, so the weak-star topology will never be defined on a space that isn't Banach. With regards to the weak-star topology, then, my question should refer to aspects of the weak-star topology on a space $E^*$ where the original $E$ is not Banach.


How to display the GRUB2 menu from the command line

I know how to use sudo grub-set-default # but I do not know how I can determine what the order is to specify the default boot (without booting and observing the menu).    Is there some way to get grub to echo the menu from the command line?  How can I figure out what 0, 1, 2, etc., are in grub without booting?


departing the US after arriving with ESTA

How does this work? i have dual Nigerian-British citizenship and i want to travel to the US from Nigeria. if I travel to the US with a british passport ( with ESTA of course) i will need to give the airline details of my UK Passport.  When departing, the airline will need my pp details on checkin and i provide my Nigerian pp details as it wont accept my british pp (saying i will need a visa).  how will the US know that the same person who entered with british pp is the same one departing with a Nigerian one?


Is this query secured from sql injection?

I Wonder if this sql query is secured from sql-injection, and if it is ok, or i should modify something.  I tried to bind the id from the GET and than if everything is ok, i use that actual query with that id.  if(isset($_GET['id']) && $_GET['id'] != null) {   $id = $_GET['id'];    $stmt = $mysqli->prepare('SELECT id FROM maps WHERE id = ?');   $stmt->bind_param('i', $id);    $stmt->execute();    $result = $stmt->get_result();    if (mysqli_num_rows($result) == 1)    {     $row = $result->fetch_assoc();       $secid = $row["id"];   } else {       header("LOCATION: index.php");   }    $sql = "SELECT    maps.id,   maps.name,   maps.description,   maps.date,   maps.mcversion,   maps.mapid,   maps.category,   maps.format,   maps.userid,   users.username,   users.rank,   users.verified,   users.mc_username,   (SELECT COUNT(*) FROM likes WHERE likes.mapid = maps.id) AS likes,   (SELECT COUNT(*) FROM downloads WHERE downloads.mapid = maps.id) AS downloads,   (SELECT COUNT(*) FROM subscribe WHERE subscribe.channelid = maps.userid) AS subscribes,   (SELECT COUNT(*) FROM views WHERE views.mapid = maps.id) AS views   FROM maps   INNER JOIN users        ON maps.userid = users.id   WHERE maps.id = '$secid'";    $result = mysqli_query($con,$sql);    if (mysqli_num_rows($result) > 0) {       $row = mysqli_fetch_assoc($result);   } else {       header("LOCATION: index.php");   }  } else {     header("LOCATION: index.php"); }


I am applying for a tourist Schengen visa type C. It is unclear if they will grant me a multiple entry visa. My currently planned trip lasts for 30 days. So what should be the duration of the insurance?   The reason why I am asking is, is the number of entries dependent upon the duration of the insurance? That is, if the insurance is valid for 30 days then does that have any effect on issuing a multiple-entry visa (considering my first trip is 30 days)?   In other words, is having a 180 days insurance necessary for getting a multiple entry visa?


Prove rigorously that the functions $f(z)$ and $\overline{f(\overline{z})}$ are simultaneously analytic.  From where do i start and what does simultaneouslt means here?   Any help is appreciated ?


I have used Xubuntu 16.04 fine for months. Today i updated some snapd package, then i restarted the system as required. And now it just won't let me log in. It replies invalid password. I tried to switch to lxde, then a tried to log in to another user account (including root) to no avail.    Then i pressed Ctrl + Alt + F1 to enter the CLI environment. Tried to log on (as regular user, then as root) and i keep getting the same message:      System is booting up. See pam_nologin(8).     I found out that pam_nologin means Prevent non-root users to login. And yet i can't log in as root! What can i do? Should i reset root password from a Live Ubuntu?    P.S. I'm so upset i'm not even looking for my Live Ubuntu and i'm writing this from Windows :( .


C++ Template enum T for functiun return type

i'm trying to have a template class that will call the adequate function for each Enum.  I Have 3 Enum : M_EnumA from class AAA, M_EnumB from class BBB and M_EnumC from class CCC.  My main class is like that  #pragma once  #ifndef HEADER_H_ #define HEADER_H_  #include "AAA.h" #include "BBB.h" #include "CCC.h"  template<typename T> class Header { public :    Header();    void Hello(T param);    AAA::M_EnumA retHello(AAA::M_EnumA e);   BBB::M_EnumB retHello(BBB::M_EnumB e);   CCC::M_EnumC retHello(CCC::M_EnumC e); }; #endif    template<typename T> Header<T>::Header() {   std::cout << "cst" << std::endl; }  template<typename T> void Header<T>::Hello(T param) {   std::cout << "hello" << std::endl;   std::cout << retHello(param) << std::endl; }  template<typename T> AAA::M_EnumA Header<T>::retHello(AAA::M_EnumA e) {   std::cout << "AAA" << std::endl;   return e; }  template<typename T> BBB::M_EnumB Header<T>::retHello(BBB::M_EnumB e) {   std::cout << "BBB" << std::endl;   return e; }  template<typename T> CCC::M_EnumC Header<T>::retHello(CCC::M_EnumC e) {   std::cout << "CCC" << std::endl;   return e; }   And my main is like that  int main() {   AAA::M_EnumA a = AAA::M_EnumA::A1;    Header<AAA::M_EnumA> *header = new Header<AAA::M_EnumA>();   Header<BBB::M_EnumB> *headerb = new Header<BBB::M_EnumB>();;   Header<CCC::M_EnumC> *headerc = new Header<CCC::M_EnumC>();    header->Hello(a);   headerb->Hello(BBB::A1);   headerc->Hello(CCC::A1);    return 0; }   But i got error LNK2019: unresolved external symbol in my main and i can't understand why. Sorry for this beginner question.


$Window.Add_KeyDown({        if ($args[1].key -eq 'Enter'){          $syncHash.GEL.Value.PerformClick() #button       } })  #error Method invocation failed because [System.Windows.Controls.Button] does not contain a method named 'PerformClick'. :171 char:5 +     $syncHash.GEL.Value.PerformClick() +     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : InvalidOperation: (:) [], RuntimeException     + FullyQualifiedErrorId : MethodNotFound


Dependencies unsatisfied for offline Broadcom installation

I just installed Ubuntu 17.1 on my Dell Precision M6500 (so the laptop is vintage 2009-2010), alongside Windows 7. When in Windows, wifi works fine (and the LED is ON, just above keyboard). When in Ubuntu, no wifi, wifi light is off, and if I go to Ubuntu Settings, the wifi page indicates that there is no wifi adapter. If I then try the lspci command, I get this for the Broadcom devices:   dell-M6500:~$ lspci -nnk |grep -iA3 broadcom 09:00.0 Ethernet controller [0200]: Broadcom Limited NetXtreme BCM5761e Gigabit Ethernet PCIe [14e4:1680] (rev 10)     Subsystem: Dell NetXtreme BCM5761e Gigabit Ethernet PCIe [1028:02ef]     Kernel driver in use: tg3     Kernel modules: tg3 0c:00.0 Network controller [0280]: Broadcom Limited BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b] (rev 01)     Subsystem: Dell Wireless 1510 Wireless-N WLAN Mini-Card [1028:000d]     Kernel driver in use: b43-pci-bridge     Kernel modules: ssb   If I then follow the instructions at , I get this:   dell-M6500:~$ ls bcmwl-kernel-source_6.30.223.271+bdcom-0ubuntu3_amd64.deb  Music Desktop                                                    Pictures dkms_2.3-3ubuntu3_all.deb                                  Public Documents                                                  Templates Downloads                                                  Videos examples.desktop dell-M6500:~$ sudo dpkg -i *.deb [sudo] password for ...:  Selecting previously unselected package bcmwl-kernel-source. (Reading database ... 126010 files and directories currently installed.) Preparing to unpack bcmwl-kernel-source_6.30.223.271+bdcom-0ubuntu3_amd64.deb ... Unpacking bcmwl-kernel-source (6.30.223.271+bdcom-0ubuntu3) ... Selecting previously unselected package dkms. Preparing to unpack dkms_2.3-3ubuntu3_all.deb ... Unpacking dkms (2.3-3ubuntu3) ... dpkg: dependency problems prevent configuration of bcmwl-kernel-source:  bcmwl-kernel-source depends on linux-libc-dev; however:   Package linux-libc-dev is not installed.  bcmwl-kernel-source depends on libc6-dev; however:   Package libc6-dev is not installed.  dpkg: error processing package bcmwl-kernel-source (--install):  dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of dkms:  dkms depends on gcc; however:   Package gcc is not installed.  dkms depends on make | build-essential | dpkg-dev; however:   Package make is not installed.   Package build-essential is not installed.   Package dpkg-dev is not installed.  dpkg: error processing package dkms (--install):  dependency problems - leaving unconfigured Processing triggers for man-db (2.7.6.1-2) ... Errors were encountered while processing:  bcmwl-kernel-source  dkms   This laptop does not support UEFI boot so there is no Secure Boot option to turn off (I also looked in BIOS and could not find anything related to secure boot). BIOS is latest (A10).  Any ideas of how to make wifi work?


Is it possible to use both Blender Render and Cycles in one render?

If I wanted to use cycles for a (example) floor and blender render for a (example) humanoid figure, how would I go about doing it? Is there a non complicated way to combine both cycles and blender render in one render output? Thanks!


How can I approach implementing the following in Drupal 7?  What I need to do is create a module which defines a new fieldable entity, called 'Company'. I have a list of, let's say, 20 fields that need to be filled out by each Company instance. These questions are predefined and some may contain custom validation.  At the moment, I'm at the point when I can add new fields to the Company entity. This works fine at the moment. My issue is that I need all these fields to be there as soon the module is installed, so adding them via the interface isn't an option.  I was wondering how can I approach this? I'd assume it comes down being able to do what can be done using the 'Manage Fields' UI programmatically.


Story about schooling in the future, using video monitors at home

It is about school in the future. In this system, all classes are taught through television and students all learn at home. Students get to decide what classes they wish to attend and teachers get paid by how many students sign up for their courses. As a result, teachers resort to tricks to get attention. One dresses up as a clown, another wears a bikini, etc. There is an older teacher who decides to teach the old-fashioned way. That's all I remember.


Why do objects appear smaller when viewed from a distance?

Yes, I know all about perspective (I'm an artist). I even have some basic knowledge of descriptive geometry. I know how it works. My question is more about why it works.   I have a sneaking suspicion it has something to do with the curvature of space. However, I'm not certain whether the two concepts are related.   Another thing that's been bothering me for a while (this may or may not be related to the question: please enlighten me) is the relation of the vanishing point to the horizon:  Strictly speaking, the geometrical horizon is where the vanishing point is. The actual horizon is a bit lower, but the difference is negligible.   Thus, if you sketch a perfectly straight street lined with buildings of equal size stretching all the way to the horizon, you shouldn't even be able to see anything beyond 2.9 miles (the distance to the horizon): all parallel lines will merge - and vanish. And yet, if the buildings are large enough, they will be visible beyond that point.     Which would suggest that smaller objects become a point source before they reach the true vanishing point, and that the true vanishing point is a lot further than 2.9 miles (which is why we can see the actual shape of the moon, as well as some of the planets: they're not point sources; they're actual disks). I would even go so far as to posit that the reason we see stars as point sources is they aren't large enough; and the Andromeda Galaxy, which appears to the naked eye as a cloud, is not a point source; which leads me to believe that the absolute vanishing point is at an infinite distance from the observer.  With all of the above in mind, my question still is - WHY do objects appear smaller in the distance?  P.S. "That's how perspective works" is not a good answer in this case unless physics has nothing more to contribute at this juncture.  P.P.S. Yes, about those angles (the light hitting the eye, etc). Why should the angle get narrower as the distance increases? Well, for one thing, that's how our brain interprets the signal it receives from the eye. I daresay if it were the other way around (i.e. if the angle got broader as the distance increased), our brain would find a way to adjust, and we'd all be saying "It's bigger because it's further away, that's how it works").


Test if the probability of two events occurring are equal

Suppose I have two independent events that occur with unknown probabilities. For example, I have two buttons, and each time I press a button there is an unknown chance that it will make a noise. I want to know if the probability that the two buttons make a noise is the same, so I run some tests. I press Button A 100 times, and it makes a noise 6 times (6%). I press Button B 200 times, and it makes a noise 16 times (8%). From this, I don't know if Button B actually has a higher chance of making the noise, or it was just luck. I want to do a hypothesis test with the null hypothesis that both buttons do have the same chance of making a noise. I'm not sure where to start though, how can I test this?


Can Newton’s law of gravitation be derived from Coulomb’s law?

I’m casually learning physics and have noticed that Newton’s law of gravitation and the electrostatic force formulas look similar. I’ve asked this question before but would really appreciate another response. Is it possible that the two laws are related? Can the law of gravitation be seen as the macroscopic averaging of Coulomb’s law? So atoms on average have negative charge (positive mass) and thus on a macroscopic scale we observe that two large bodies (eg planets) attract rather than repel. Would it help if we assume that masses can be positive as well as negative? Apologies as I’m not a physicist (rather a data analyst) and these are probably dumb questions.


I've been trying to teach myself some group theory and have come a across that has really stumped me. It is as follows:   Prove that in any finite group $G$ with a subgroup $H$ of order exactly half that of $G$, the left and right cosets of H in G are the same, i.e. for all $g ∈ G$ we have $gH = Hg$ and show that this implies that $gHg^{-1}= H$.  Any help is very greatly appreciated.


Limit definition of pseudoinverse: $A^+ b$ is as close as possible to $y$ in terms of the Euclidean norm $\lVert Ax-b\rVert_2$

I am currently studying  answer on the Moore-Penrose pseudoinverse and the Euclidean norm by the user "Etienne dM". The first point of their answer proceeds as follows:  Let $x$ be $A^+y$.  Let me begin by the second point. For all $z$, we have: \begin{align} \lVert Az-b \rVert_2^2 &= \lVert Ax-b \rVert_2^2 + \lVert A(z-x) \rVert_2^2 + 2 (z-x)^TA^T(Ax-b)\\ & \geq  \lVert Ax-b \rVert_2^2 + 2 (z-x)^TA^T(Ax-b) \end{align} Moreover, because $(AA^+)^T = AA^+$, $$ A^T(Ax-b) = ((AA^+)A)^Tb - A^Tb = 0$$ Thus, we prove that for all $z$, $\rVert Az-b \lVert_2^2 \geq\rVert Ax-b \lVert_2^2$, that is to say $A^+b$ is as close as possible to $y$ in term of the Euclidian norm $\lVert Ax-b\rVert_2$.   I realise that $x = A^+ y$, but I don't understand how any of this implies that "$A^+ b$ is as close as possible to $y$ in terms of the Euclidean norm $\lVert Ax-b\rVert_2$". I would greatly appreciate it if people would please take the time to explain this to me.


Unable to update ubuntu via terminal through a proxy server

I am currently a newbie in ubuntu. I have ubuntu 14.04 and want to update it via terminal. I use proxy server (which requires authentication ie username and password)to access internet. I can easily surf internet but when it comes to Ubuntu software centre or an update through terminal, i am unable to do it.Terminal always gives 'error 407 proxy authentication required' and then fails. Please help me with this.


Ibus incompatible with Tor Browser in 13.10

I have recently updated to 13.10 from 13.04 and noticed a compatibility issue between the new Ibus and the Tor Browser.  Basically, the Tor Browser does not accept any keyboard inputs, while all other programs do. I tested this with the 64 bit versions 2.3.25-11 and 2.3.25-13 and the 32 bit version 2.3.25-13.  According to this thread, quitting ibus "fixes" the problem:    Any ideas on how to fix this?


GTA5 Online: If I log off and come back in an hour will the garage buy cars again?

Okay, so I want to sell another car to the garage but it takes a full game day.  Do I need to be logged in with my game on to do this, or can I turn it off, come back in 48 minutes, and sell again?  Also, do I have to wait 48 minutes, or will it be at midnight of the following GTA-day that they will start purchasing again?  THANKS!


Formula for scaling weapon damage with size?

As weapons get larger or smaller, they tend to deal different damage dice.   Most weapons list damage for Small and Medium weapons:   There is also a chart for Tiny and Large weapons:   But what about Fine or Huge (and bigger) weapons? Normally I would try to extrapolate some formula from the existing tables, but those tables seems completely ad-hoc and a little random. Notice how both a 1d12 and a 2d6 become 3d6 weapons at large?  In my specific case, I have a character with the  and he's going to be a Huge creature wielding something that does 2d6 at Medium. That's 3d6 at Large, but what is it in Huge? 3d8? 4d6? 4d8?  An official reference would be nice, but even just some stats from a known Huge creature wielding a similar weapon.  Bonus Question: Is it just me or are the damage dice really non-sensical? Weapons double or halve in weight as they change size, shouldn't the damage dice be doing something similar? I mean if a 10lb weapon deals 1d10, shouldn't a 20lb version of the same thing deal more than just 1d12?  EDIT: Looks like 3.5 has a full table for this. The general formula is +50% rounded down. However, the rounding down is quite significant at larger sizes.


Degree of a splitting field is no greater than $n!$

Is it possible to prove that if $P$ is a polynomial of degree $n$ then the degree of its splitting field is no greater than $n!$ without using notion of Galois group?


Can someone help me understand this infinite product question?

Can someone walk this through for me, so I understand how to get from $A$ to $B$? $$\prod_{k=1}^K e^k=e^{K(K+1)/2}$$


Users with high number of badges break layout

Possible Duplicate:          I was checking the  earlier and noticed that Jon Skeet's number of badges is too large to be displayed in the layout:        But then I wondered, is it a bug or is it just so because one can't put Jon Skeet in a box?  Bug or not bug? That is the question.


Add Google as Default Search Provider in IE 11

Google Chrome becomes more and more unusable: crashing, eating memory, etc. So I decided to come back to IE and use it as my default browser. Chrome used to be much faster. But not recently. It slows down all my laptops now.  The first thing I wanted to do after starting using IE is to change Bing to Google Search as the search engine for toolbar searches.  I go to that page to add Google Search Add-on:    And it is not there. I tried on both Win8 and Win7. Am I missing something? Can anybody else install Google Search Add-on for IE?  Thanks!


Changing spacing in chapter titles and sections.

As stated, I need to change the spacing between the top of the page, the chapter name and title. I'm currently using \allsectionfont{\centering \fontsize{15}{15}\selectfont} to control the size and where they are placed. There is still a huge gap between where it says "Chapter 1" and the top of the page, as well as a gap between "Chapter 1" and the name of the chapter. How can I make this gap vanish?


What is the difference between the Taylor and Maclaurin series?

What is the difference between the Taylor and the Maclaurin series? Is the series representing sine the same both ways? Can someone describe an example for both?


Definition of locally pathwise connected

I have two definition of this property.     Def 1: A space X is said to be locally path connected at x if for every (open) neighborhood U of x, there is a path-connected (open) neighborhood V of x contained in U. If X is locally path connected at each of its points, then it is said to be locally path connected.   Munkres, Topology     Def 2: A space X is locally pathwise connected if each point has a nhood base consisting of pathwise connected sets.   Willard, General Topology  Notice, Def 1 is speaks of an open neighborhood, Def 2 of a generic neighborhood.  Are the two definition equivalent, if not which one is preferable?


Prove that in any GCD domain every irreducible element is prime

The proof of the following proposition is not completely clear to me. I get everything up until the bold part and I have a feeling some crucial steps are omitted, can anybody help clear this up?     Let $R$ be an integral domain. If every two elements of $R$ have a greatest common divisor, then every irreducible element in $R$ is prime.   Proof:  Consider an irreducible element $p \in R$ and $x,y \in R$ such that $p\vert xy$. Suppose now that $py$ and $xy$ have a greatest common divisor $z$ in R. We want to conclude from this that $p \vert x$ or $p \vert y$. This is obvious if $xy = 0$, so we may assume that $xy \neq 0$. Then $z \neq 0$. As both $p$ and $y$ divide each of $py$ and $xy$, we have that $z = pu = yv$ for certain $u,v \in R$. Using the cancellation law with $\boldsymbol z \boldsymbol \neq \boldsymbol 0$, we obtain that $\boldsymbol v \boldsymbol \vert \boldsymbol p$. As $p$ is irreducible, either $v \in R^\times$ (i.e. the set of invertible elements of $R$) or $v \sim p$ (i.e. $Rv = Rp$). If $v \sim p$, then $p \vert x$. If $v \in R^\times$, then $p$ divides $v^{-1} pu = v^{-1} z=y$.


If we have a function $f:A \rightarrow B$, then one way to give meaning, I think, to this function, in terms of set theory, is to say, that $f$ is actually a binary relation $f=(A,B,G_f)$, where $G_f \subseteq A \times B$ is the graph of the function. Now my question is: what is $f$ if   $\bullet \ A=\emptyset, \ B\neq\emptyset$,?  $ \bullet \ B=\emptyset, \ A\neq\emptyset$ ?  $ \bullet \ B=\emptyset, \ A=\emptyset$ ?  (Another way to formulate this, I think, would be: How do the sets $\emptyset\times B,\ A\ \times \emptyset, \ \emptyset \times \emptyset $ look like? Are they all $\emptyset$ ?)


voltage on Oscilloscope without signal applied

I am doing some measurement on Scope ( non-isolated) , my set up is like this -Scope is connected to 230V line mains with only two pin plug ( Earth or ground not used) -channel is connected with voltage probe -None of probe is hooked to any measurement point yet.  I observer when I touched any probe positive lead, I saw some high voltage waveform on screen,   a) First case :- I am reading 240Vac peak to peak and 82 Vrms on scope also can see sine wave on screen . I was sitting on chair , any I wore shoes and my shoes touching to ground.  b) First case :- I am reading 170Vac peak to peak and 50 Vrms on scope also can see sine wave on screen . I was sitting on chair , any I lift my legs form ground.  Q1) Is everything is right with setup  Q2) is it true voltage , then why i am not getting shock by touching probe lead  Q3) Why voltage shown when I am touching the lead, does I am generating the voltage from my body.


I know monoalphabetic ciphers are weak, but my message recipient doesn't like taking the time for the decryption process. I've tried Vigenere, Gronsfeld, Beaufort and Digraphic Ciphers, but he doesn't decrypt them. What is a good choice for speed and enough security against novice cryptanalysts? One-Time-Pad is highly impractical, and Solitaire takes too much time, what is the best bet? Your suggested answer gives me systems that are impractical and slow. I don't need high security, merely simple yet strong ciphers not mentioned above.


How can I create a keyboard shortcut to access a specific folder in Finder?

I have been using Total Commander as a file manager on Windows for years. There is one feature I miss a lot in Finder: a shortcut to one specific folder.  Saying I have a folder ~/Downloads, ~/Dropbox, ~/Code, ~/Books. Is it possible to setup a customized keyboard shortcut for each of them?   In Total Commander you could do ctrl+D+1/2/C/B/... etc.


Say, previously I received a payment of $100 from Party A, and NOW I am describing the amount of the payment: "The amount of the payment was $100" (past tense).  Must the past tense be used? Is it possible to use the present tense ("The amount of the payment is $100")?


What is the proof that the two below are equal?

Can you help me to prove the following equality ?


Is the series $ L = \sum_{i=2}^{\infty } \frac{1}{n \log(n)} $ convergent or divergent?

Does $ L = \sum_{i=2}^{\infty } \frac{1}{n \log(n)} $ converge or diverge?  I established that:  $$ L \le I   = \int^{\infty}_{2} \frac{1}{n \log(n)}   = \lim_{n \to \infty} [ \ln(\log(n)) - \ln(\log(2)) ], $$ and as $ \lim_{n \to \infty} \log(x) = \infty $, then $ L $ diverges.  But I'm not sure:   of the sense of the inequality, about the conclusion.


Fluid Simulation, make the fluid to be absorbed

I have a fluid falling on top of a plane.  I want the fluid (water) to be absorbed by the plane, like a cloth would do.  How can i do that?    Thank you


Let $G ⊂ S_7$ be a subgroup of order 8. Then there exists $i$ such that $\sigma(i)=i.$

I am looking for the solution of the following question.  Let $G ⊂ S_7$ be a subgroup of order 8. Prove that there exists $i ∈\{1,...,7\}$ such that for any $σ ∈ G$ we have $σ(i) = i$  Thank you in advance.


Matching points to polygons and handling points NOT in polygons

I have two GeoDataFrames: one with 191k address points and another with 18 polygons representing catchment areas for specific schools. Theoretically, every address should fall into one of the zones. When running my code, I get the following error: ValueError: Length of values (191888) does not match length of index (191921)  I suspect that there are 33 points that are not matched to a polygon. import geopandas as gpd import os  from shapely.geometry import Point, Polygon   pointpath = "/path/to/address points/" point_df = gpd.read_file(os.path.join(pointpath,"addresses.shp"))   shapepath = "/path/to/catchment areas/" shape_df = gpd.read_file(os.path.join(shapepath,"catchments.shp"))   school_list = [] for i in range(len(point_df)):     pt = Point(point_df['geometry'][i])     for index, row in shape_df.iterrows():         poly = Polygon(row['geometry'])         if(pt.within(poly)):             school_list.append(row['school_name'])             print(i) point_df['zoned school']=school_list point_df.to_excel(os.path.join(pointpath,'foo.xlsx'))  First off, is this the most efficient way of performing this task? Second, is there a way to loop through the catchment areas and if there is no match, enter something like "no match found" so that the number of list items matches the number of dataframe rows?


I need to build a function which parses the domain from a URL.  So, with   http://google.com/dhasjkdas/sadsdds/sdda/sdads.html   or  http://www.google.com/dhasjkdas/sadsdds/sdda/sdads.html  it should return google.com  with   http://google.co.uk/dhasjkdas/sadsdds/sdda/sdads.html  it should return google.co.uk.


Null pointer exception sketching a polygon

The Program I'm trying to make is supposed to draw a Polygon using points stored in an ArrayList. I rechecked the code and I am also using the driver, but when I try to run the program, it gives me a NullPointerException when I try to add coordinates for the program to use when drawing.  import java.awt.geom.*; import java.util.ArrayList; import gpdraw.*; public class IrregularPolygon {     private ArrayList <Point2D.Double> myPolygon;     DrawingTool myPen;     SketchPad myPaper;      double dblPerimeter;     double dblSegment;     double dblArea;      public IrregularPolygon()//Creating the sketchpad and pen     {         myPaper = new SketchPad(500,500);         myPen = new DrawingTool(myPaper);     }      public void add(Point2D.Double aPoint)//Adds to the array     {         myPolygon.add(aPoint);// This is where the problem is I think, I don't know what to do     }      public void draw()//This method draws the polygon     {         for(int x = 0; x < myPolygon.size() - 1 ; x++)         {             myPen.down();             myPen.move(myPolygon.get(x).getX(),myPolygon.get(x).getY());             myPen.up();         }        }       public double perimeter()//This method finds the perimeter     {         for(int x = 0; x < myPolygon.size() - 1; x++)         {             dblPerimeter += myPolygon.get(x).distance(myPolygon.get(x+1));         }         return dblPerimeter;     }      public double area()//This method finds the area     {         for(int x = 0; x < myPolygon.size() - 1; x++)         {             double X1 = (myPolygon.get(x).getX());             double Y1 = (myPolygon.get(x).getY());             double X2 = (myPolygon.get(x + 1).getX());             double Y2 = (myPolygon.get(x + 1).getY());             dblArea += (X1 * Y2 - Y1 * X2);          }         return dblArea;     } }   and the programs runs from this driver:  import java.util.*; import java.awt.geom.Point2D; public class IrregularPolygonDriver {     static boolean blnReadyToDraw = false;     static Scanner in = new Scanner(System.in);     public static void main(String[]args)     {         int num;         IrregularPolygon poly = new IrregularPolygon();         while(blnReadyToDraw == false)         {             System.out.println("Would you like to add a point, find the perimeter, or calculate the area?");             System.out.println("To add a point, enter 1; to find the perimeter, enter 2; to find the area, enter 3");             num = in.nextInt();             if(num == 1)             {                 double dblNum1;                 double dblNum2;                 Point2D.Double dblNumber;                 System.out.println("Enter an x value and a y value: ");                 dblNum1 = in.nextDouble();                 dblNum2 = in.nextDouble();                 dblNumber = new Point2D.Double(dblNum1,dblNum2);                 poly.add(dblNumber);                 System.out.println("Keep adding points until you are done drawing the figure.");             }             else if(num == 2)             {                 poly.perimeter();             }             else if(num == 3)             {                 poly.area();             }             else             {                 blnReadyToDraw = true;                 System.out.println("Preparing to Draw");             }         }         poly.draw();     }   }


In Disney canon, what is the origin of the name of the Millennium Falcon?

What is the origin of the Millennium Falcon's name,  within Disney canon?  Obviously the falcon is in reference to the bat-falcon (as per ) but what about the 'millennium' part?


Why does Voldemort always say 'Avada Kedavra' instead of casting it wordlessly?

Competent wizards, (as Voldemort clearly is) can effectively cast spells without speaking.  Dumbledore does this to reveal Harry under his invisibility cloak:     J.K. Rowling: Dumbledore, who could perform magic without needing to say the incantation aloud, was using ‘homenum revelio’   Why does Voldemort always say 'Avada Kedavra' when casting the spell?


Any issue installing and running 20.04 LTS on Ryzen 5 5500U processor laptop? Are Intel i5 's clearly better for Ubuntu in general?

Is there a general advice to go for Intel core processor (i3/5/7/...) devices when using Ubuntu 's instead of Ryzen's (3,5,...) or specifically Ryzen 5 5500 U?


I've accidently made an answer community wiki. How can I undo this?

Possible Duplicates:             I added  and edited it to correct a mistake and add more information. It was made community wiki after 12 edits, but it is a regular answer. How can I undo this?


How can I trigger a Notification Center notification from an AppleScript or shell script?

I'd love to be able to take advantage of 10.8's Notification Center features in AppleScripts and shell scripts I write.  Is there a built-in command or a third-party library I can use from either an AppleScript or shell script?  Ideally the type and icon of the notification could be controlled, but even just the ability to trigger a basic banner with a stock icon (but custom text) would be appreciated.


I am experiencing a issue in my 3d blender model. It seems as if hard shadows are appearing on my model, but it is not a lighting issue as when I add a sun lamp the black spots are still there as seen below.  It is also not an overlapping issue as i can find no overlapping quads over my whole model. I will leave the blender model below so that you can look at it yourselves and hopefully fix this issue :)


I was wondering if in the novel we knew about some deaths occurring before Kayaba announcement. I remember that in the anime, Kirito plays a bit with Cline before realizing that the log off option has disappeared. Then all the people are summoned to the city and learn about the fact that if they die in the game, they also die in real life.  I don't remember any players dying before the announcement in the anime, except for those who are not waking up and their relative pulling off their NerveGear thus causing death, but maybe in the light novel, some guys died without even knowing it just while being defeated by a mob (which seems awful for me).  Do we know about some players dying before that while thinking they are still in a normal game?


In Star Trek 2 (movie) The Wrath Of Khan, why does Khan wear the federation emblem?

Watching the film again, I noticed that once Khan gets on the bridge of the Reliant, he has a Federation emblem on a neck chain. Previously on the planet Khan was well covered (although it might appear in an earlier scene).    Here it is on Scottie's belt;    Some of Khan's crew wear ornament, although more in keeping with their gritty, weathered, simple eco time on Ceti Alpha V.    Q. So my question is, if Khan hates Kirk with a vengeance and presumably the Federation for marooning him on a remote planet for 20+ years (leading to the death of his wife), and he originates from a pre-Federation time period, why would he wear the Federation's emblem on his throat? Is it possibly a ritualistic thing - brandishing the teeth or bones of an enemy he has defeated for machismo / domination?   Thanks


Is "yesterday" a noun, an adjective or an adverb?

Are words like "yesterday" and "tomorrow" considered nouns, adjectives, or even adverbs?  I'm getting mixed signals from several references.  In a case like "I have an important meeting tomorrow," it seems as if they're nouns.  But what about "Yesterday afternoon?"


Let $f(z) = \sum_{n = 0}^\infty a_nz^n$ be the Taylor series around $0$. Prove that lim $a_n/a_{n+1} = z_0.$

Let $f(z) = \sum_{n = 0}^\infty a_nz^n$ be the Taylor series around $0$ of a function which is analytic in $\mathbb{C}$ \ ${z_0}$, $z_0\neq 0$ and has only a simple pole at $z_0.$ Prove that $lim_{n \rightarrow \infty}$ $a_n/a_{n+1} = z_0.$  It is clear that the radius of convergence is $|z_0|$ and so that if it does converge, it converges to something with distance from the origin $|z_0|.$  But the rest I am not sure about.  Some help would be fantastic.  Thank you.


Let $\ell^1$ be the space of absolutely summable real or complex sequences. Let us say that a sequence $(x_1, x_2, \ldots)$ of vectors in $\ell^1$ converges weakly to $x \in \ell^1$ if for every bounded linear functional $\varphi \in (\ell^1)^*$, $\varphi(x_n) \rightarrow \varphi(x)$ as $n \to \infty$. How may I show that weak convergence, in this sense, is the same as the usual convergence-in-norm? It's clear the weak convergence implies pointwise convergence, but that's not good enough to conclude strong convergence...  By linearity, it suffices to prove that if $\varphi(x_n) \longrightarrow 0$ for every $\varphi \in (\ell^1)^*$, then $\| x_n \| \longrightarrow 0$. Let $x_n(k)$ be the $k$-th component of the vector $x_n$. Then, $x_n(k) \longrightarrow 0$ for every $k$, so $\sup_n |x_n(k)| < \infty$ for each $k$, and this implies $$\lim_{N \to \infty} \lim_{n \to \infty} \sum_{k=1}^{N} |x_n(k)| = 0$$ This is almost what I want, but the limits are the wrong way around. The obvious next thing to try is to construct some clever functional, or even a family of clever functionals, but I can't think of anything useful here. I can see that pointwise convergence alone is not good enough — if $x_n$ is the standard basis vector, then $x_n \longrightarrow 0$ pointwise, but $\| x_n \| = 1$ for all $n$. The fact that it doesn't converge strongly can be detected by the linear functional $\varphi(x_n) = \sum_k x_n(k)$, but I'm at a loss as to how to generalise this.


How create Makeself self executable archive file in LINUX?

I want to create a self-executable archive using Makeself. I referred to  but didn't understand anything from it. What are the steps for making a Makeself self-executable archive?


prepareStatement pst throws java.lang.NullPointerException

I'm trying to query my database and display in a combo box. But I constantly get the same error, so Im not sure now where the problem is exactly, I get java.lang.NullPointerException everytime I click on the combobox  this is my code:  ``    public Sell_Tick()    {      initComponents();      FillRouteCombo();     con = CreateDB.getConnection();          if(con!=null)     {         System.out.println("Successful DB Connection");     }  } private void FillRouteCombo()     {         try          {             pst=con.prepareStatement("select * from routes");             rst= pst.executeQuery();             while(rst.next())             {                 String getroutes=rst.getString("destfrom");                  destfrom.addItem(getroutes);               }         } catch (Exception e) {             System.out.println(e);         e.printStackTrace();         }      }   The error i get is this  java.lang.NullPointerException      Successful DB Connection     at Sell_Tick.FillRouteCombo(Sell_Tick.java:47)     at Sell_Tick.<init>(Sell_Tick.java:34)     at StartPage.TicketOperationActionPerformed(StartPage.java:1710)     at StartPage.access$5300(StartPage.java:52)     at StartPage$33.actionPerformed(StartPage.java:1121)  and line 47 is pst=con.prepareStatement("select * from routes");


Creating or adding geometry colunm fails even with postgis enabled

I'm trying to add a geometry colunm to a table in a database with postgis extention enabled (other tables in this schema even have geometry colunms), but it fails:  ALTER TABLE my_schema.my_table ADD COLUMN geom geometry(MultiPolygon, 4326);   gets me an error:  ERROR:  type "geometry" does not exist   although   CREATE EXTENSION postgis;   returns   ERROR:  extension "postgis" already exists   I'm running Postgres 9.5, but I cannot tell postgis verion because it throws another error   ERROR:  function postgis_full_version() does not exist   Although postgis is listed under extensions in pgadmin.


Looking for a short story about a robot evolving to have supernatural powers

I'm looking for a short story from about 50 years ago about a robot who escapes after being slated to be melted down and discovers while in hiding that it has evolved to have some supernatural powers.


What does it do and what are its applications? I am currently testing the subtitle of my beamer presentation for its string length to decide about line spacings. Could it be simpler using \empty?  If I just try \empty{word}, it seems that nothing happens. Of course, I do not expect to get a string length, but I thought that I could check the title for being empty or not.  This is how I add space by checking beamer's subtitle:  \usepackage{xstring} \StrLen{\insertsubtitle}[\subtitlelen]  \ifnum\subtitlelen>0{     \vskip0.2cm }\fi   I try to clarify my question as requested in the comments: I thought that I could check for \empty. \StrLen is easy to understand because you can output that value as text. However, this does not work for \empty so I wondered how one would use it to accomplish the same task.


I was wondering if there is a way to get the computer name in Java? I have seen several answers that feature java.net.InetAddress. However I was wondering if there is a way that does not use the network?  (As a side question, is the computer name only a network thing anyway, so therefore has to be done this way??)


showing $\psi: R\to \mathbb C$ is ring isomorphism.

Below is an example from I.N. Herstein:       Let  $R=\Bigg\{\left( \begin{array}{ccc} a & b \\ -b & a \end{array} \right)\Bigg|a,b\in \mathbb R\Bigg\}$ and let $\mathbb C$ be the field of complex numbers. Define $\psi :R\to \mathbb C$ by $\psi\left( \begin{array}{ccc} a & b \\ -b & a \end{array} \right)=a+bi.$       It is asked to prove that $\psi$ is a ring isomorphism of $R$ onto $\mathbb C$ .    can anyone help me with some hint how to prove the ring isomorphism.


I am trying to draw a bar chart in which each independent variable has multiple bars showing its performance in different areas. The problem I am having here is that the bars for the third variable is not showing up. The code I am using is shown below  \begin{center} \begin{tikzpicture} \begin{axis}[ x tick label style={ /pgf/number format/1000 sep=}, ylabel=Passenger Count, enlargelimits=0.05, legend style={at={(0.5,-0.15)}, anchor=north,legend columns=-1}, ybar interval=0.5, symbolic x coords={1st Class, 2nd Class, 3rd Class}, grid=major ] \addplot coordinates {(1st Class,6) (2nd Class,6) (3rd Class,324)}; \addplot coordinates {(1st Class,0) (2nd Class,98) (3rd Class,81)}; \addplot coordinates {(1st Class,41) (2nd Class,56) (3rd Class,45)}; \addplot coordinates {(1st Class,169) (2nd Class,24) (3rd Class,41)}; \legend{0-10,10-20,20-30,$>30$} \end{axis} \end{tikzpicture} \end{center}


How can I list the all the packages installed and uninstall unwanted ones from that

I'd like to output a list of all installed packages into a text file so that I can review it and bulk-install on another system. I even want to be able to uninstall unwanted ones. How would I do this?


Context I have a scenario in which i have to read the file data from Directory (I/O) after 5 minutes and read the content of the file using TPL and after reading it i have to show the file content in a Grid to some Windows form ?  Questions:  I have created the windows service and schedule it to run after every 5 minutes and it reads the files from the specified directory but now the problem is how i will show the data to grid because its a separate application written using WPF. Is there a way to get data from Windows service and show to windows form ?  Thanks


What FLOSS skype alternatives are available?

Given Skype's slow development speed for the GNU/Linux version and its recent acquisition by Microsoft, I am looking for alternative softwares.  What  Skype alternatives are available?


decoupling and integrating differential equations

I am having trouble with the process of decoupling. If I have $$\frac{dx}{dt}=-x+y$$ $$\frac{dy}{dt}=-x-y$$  I am trying to figure out how to solve for $x(t)$ and $y(t)$ by decoupling the system so that I only have one variable but I can't seem to get anywhere


How prove this $\prod_{1\le i<j\le n}\frac{a_{j}-a_{i}}{j-i}$ is integer

let $a_{i},i=1,2,\cdots,n$ be postive integer ,show that $$1^{n-1}2^{n-2}\cdots (n-2)^2(n-1)|\prod_{1\le i<j\le n}(a_{i}-a_{j})$$  I know this $\prod_{1\le i<j\le n}(a_{i}-a_{j})$ is  Vandermonde  determinants,and I found $$1^{n-1}2^{n-2}\cdots (n-2)^2\cdot (n-1)=1!2!3!\cdots (n-1)!=\prod_{1\le i<j\le n}(j-i)$$ we only prove $$\prod_{1\le i<j\le n}\dfrac{a_{j}-a_{i}}{j-i}$$ is integer  maybe consider Vandermonde determinants ? But I can't prove this


Is there an alternative to Adobe AfterEffects?

Is there a After Effects like software for Ubuntu (or for free)  Adobe After Effects is a compositing, compositional and post-production video tool. If you think about green-screening, those cool titles/credits, overlays with people's names, infographics... it's all that stuff, and a lot more. Like motion photoshop, in full hd.


Mentioning my clinical depression in a statement of purpose

I have been struggling with clinical depression for over an year now and that has affected my grades. Is it a good idea to mention that in a statement of purpose while applying to a university (for a M.Sc+Ph.D programme)?


Why didn’t anyone dial Abydos before Daniel solved the mystery of the seventh symbol?

From what I recall from the movie, Daniel only finds the seventh symbol... however when he explain they give way to show him the star gate and they put their sequence in the dialing computer. This proves the dialing computer was prepared to dial 7 chevrons.  It’s also stated they’ve also tested the 6 previous symbols in the order they appear on before, one has to assume only to fail when they insert the 7th, making them aware of the fact you can, at least dial 7th chevrons.  With 39 chevrons on the gate and 6 already locked in, that leaves 33 to try to get a lock. Those are not that many not to go and simply try one by one so... how come nobody brute forced the thing?


How do we initialise unpacked arrays in Verilog?

Suppose I declare an unpacked array of size say 8 bits wide. reg b[7:0];  If I want to assign b[7] = 1,b[6] = 1, b[5] = 1, ......b[0] = 1, then apart from assigning value to each bit is there a way to assign any combination of bits say 8'bA8, to b? For instance if I execute this code(below) in verilog: module tb();     reg [7:0]a;     reg b[7:0];     initial begin         $monitor("a = %b,b = ",a);         a = 8'hA8;         b = 8'hA8; // Line 7     end endmodule  I get this error: C:\iverilog\bin>iverilog -o a test.v test.v:7: error: Cannot assign to array b. Did you forget a word index? 1 error(s) during elaboration.  I am using Icarus Verilog on a command prompt on Windows 10 operating system.


I run a proxy server with squid and I've just got a report that a user of mine tried a ddos using my proxy. I can I block such requests? Ex: Allow just max 5 requests on the same domain on the same minute?  LATER EDIT max 5 requests per minute for the same URL


Having inside delimiters same size as outside ones

I want to define a set    $S= \left\{   \left[\matrix{ a &b \cr a^2 & b^2\cr }\right] \left| \right.  a, b  {\rm \  real \  numbers}  \right\} $   How do I make the separating bar |  same size as the  matrix delimiter?