When I plug my flash drive in the USB I get the message that I have to Format the disk in order to use  it. Does that  mean that I have already lost all of my data?

I have a USB flash drive which is no longer recognized by my computer. Windows Disk Management and DiskPart report No Media with no storage space (0 bytes) on the drive and I cannot partition or format the drive:     If the drive appears in Windows Explorer, trying to access it returns an error message indicating that there is no disk inserted, such as the following:     Please insert a disk into drive X:.   Various disk partitioning and data recovery utilities don't recognize the drive or only give a generic name for the drive and cannot access the contents of the drive.  What can I do? How do I recover data from the drive?     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


Today I did sudo apt upgrade and then, as a double-check, did sudo apt update.  The latter terminated with: Hit:5 http://dl.google.com/linux/chrome/deb stable InRelease                                        Get:6 https://repo.skype.com/deb stable InRelease [4,502 B]                                         Err:6 https://repo.skype.com/deb stable InRelease   The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository <se-um@microsoft.com> Fetched 4,502 B in 5s (894 B/s) Reading package lists... Done Building dependency tree        Reading state information... Done All packages are up to date. W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://repo.skype.com/deb stable InRelease: The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository <se-um@microsoft.com> W: Failed to fetch https://repo.skype.com/deb/dists/stable/InRelease  The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository <se-um@microsoft.com> W: Some index files failed to download. They have been ignored, or old ones used instead.  In an attempt to clear this problem, I called sudo apt remove skypeforlinux and then did another sudo apt update.  The update again terminated with the message about the invalid signature. How can I clear up this invalid signature problem? $ uname -mrs Linux 5.4.0-77-generic x86_64 $ lsb_release -d Description:    Ubuntu 20.04.2 LTS

After a recent apt update && apt full-upgrade I started getting the following error when running apt full-upgrade subsequently: Get:4 https://repo.skype.com/deb stable InRelease [4,502 B]                                         Err:4 https://repo.skype.com/deb stable InRelease   The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository <se-um@microsoft.com> W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://repo.skype.com/deb stable InRelease: The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository <se-um@microsoft.com> W: Failed to fetch https://repo.skype.com/deb/dists/stable/InRelease  The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository <se-um@microsoft.com> W: Some index files failed to download. They have been ignored, or old ones used instead.  Is there a way to correct this, or is it down to Microsoft/Canonical to produce/update the necessary key signatures?


How do I UNINSTALL Cortana, not "disable" it.   Disabling Cortana and Uninstalling Cortana are very different things...   My main concern is Windows magically "re-enabling" Cortana if I disable her vs if she is removed it may be harder/less likely for Windows to re-enable/start Cortana.  See -->      How to Disable Cortana has many answers in the marked duplicate, but I would love to see this thread re-opened as a separate thread for people whom want to completely delete/uninstall/remove etc Cortana from their Windows System.

Windows 10 has Cortana, which I don't like. I disabled it as soon as I could. However, looking in Task Manager, the process for Cortana is still running, and can't be effectively terminated: ending the task simply results in the process respawning a few seconds later. Using the command  taskkill /IM Cortana.exe /F   has the same result: the process respawns.  Is there any way to disable Cortana so that the process doesn't keep running in the background, and doesn't respawn if terminated?


I answered a question with a bounty and my answer was accepted, but the question was closed (it was flagged as needing to be more focused). What happens to the bounty? I didn't get it, and now there seems to be no trace of it. Answer in question:  EDIT - This isn't actually a duplicate of the linked question. The referenced question refers to a bounty that was awarded and then lost, while this one refers to a bounty on an accepted answer that was never awarded. Details are however clarified in , in the section What happens if a bounty question is closed or deleted? It turns out a moderator refunded the bounty and closed the question, and the OP accepted my answer shortly after. The bounty had to be refunded to close the question. Since the bounty had already been refunded and the question closed, the bounty was not awarded.

It seems that  was closed as not constructive.  While I could argue on the "not constructive" part, especially because it was already protected and made a CW, I'd be especially interested on what happened to my earned bounty.  I checked the reputation recalc page and it is gone. I am a little bit confused because I thought .


I've nearly got this working.  I wanted to know if there was a much better way.      function replaceURLWithHTMLLinks(text) {     text = text.replace(/a/g, "--ucsps--");     text = text.replace(/b/g, "--uspds--");     var arrRegex = [         /(\([^)]*\b)((?:https?|ftp|file):\/\/[-A-Za-z0-9+&@#\/%?=~_()|!:,.;]*[-A-Za-z0-9+&@#\/%=~_()|])(\))/ig,         /(\([^)]*\b)((?:https?|ftp|file):\/\/[-A-Za-z0-9+&@#\/%?=~_()|!:,.;]*[-A-Za-z0-9+&@#\/%=~_()|])(.?\b)/ig,         /()(\b(?:https?|ftp|file):\/\/[-a-z0-9+&@#\/%?=~_()|!:,.;]*[-a-z0-9+&@#\/%=~_()|])(.?\b)/ig];     for (i = 0; i < arrRegex.length; i++) {         text = text.replace(arrRegex[i], "$1a$2b$3");     }     text = text.replace(/a([^b]*)b/g, "$1");     text = text.replace(/--ucsps--/g, "a");     text = text.replace(/--uspds--/g, "b");     return text; } var elm = document.getElementById('trythis'); elm.innerHTML = replaceURLWithHTMLLinks(elm.innerHTML);   Any thoughts?

I am using the function below to match URLs inside a given text and replace them for HTML links. The regular expression is working great, but currently I am only replacing the first match.  How I can replace all the URL? I guess I should be using the exec command, but I did not really figure how to do it.  function replaceURLWithHTMLLinks(text) {     var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/i;     return text.replace(exp,"$1");  }


Very new to SQL and I built a DB that stores information about companies. In the query below, I am trying to display the founder and ceo's name, but I am getting ambiguity errors.   I joined the founder table and ceo table onto the person table which stores the first and last name of the ceo/founder. The foreign key shared among all 3 tables is pid (person ID). I ran into issues with my select statement when I tried to return the names. I then tried adding the joined table name in from of the column name (founder.first_name and ceo.first_name), but that didn't work.  SELECT co.ein,        company_name as Company,        CONCAT(fo.first_name,' ',fo.last_name) as Founder,        CONCAT(ceo.first_name,' ',ceo.last_name) as CEO,        CASE          WHEN last_price IS NULL THEN '-'          ELSE CONCAT('$',FORMAT(last_price,2))        END as 'Current Stock Price' FROM company co LEFT JOIN stock s ON co.ein = s.ein LEFT JOIN ceo ON co.ein = ceo.ein LEFT JOIN founder fo ON co.ein = fo.ein LEFT JOIN person p ON ceo.pid = p.pid LEFT JOIN person ON fo.pid = p.pid   I need to return the Company Name, Founder's Name, CEO's Name, and Current Stock Price.

I have 2 tables. One (domains) has domain ids, and domain names (dom_id, dom_url).  the other contains actual data, 2 of which columns require a TO and FROM domain names. So I have 2 columns rev_dom_from and rev_dom_for, both of which store the domain name id, from the domains table.  Simple.  Now I need to actually display both domain names on the webpage. I know how to display one or the other, via the LEFT JOIN domains ON reviews.rev_dom_for = domains.dom_url query, and then you echo out the dom_url, which would echo out the domain name in the rev_dom_for column.  But how would I make it echo out the 2nd domain name, in the dom_rev_from column?


i create a function that move element by 1 px and repeat it with a specefic time with setInterval heres The Code :   var Elementt = document.querySelector('.h'); var left = 0; var speed = 100; var limit = 10;  setInterval(function MoveByOnepixel() {     if (left > limit ){      } else {         Elementt.style.left = left + 'px';         left++;     }  }, speed);   The thing is when Left > limit is the  setinterval stops or going to repeat without stop ?  If it repeat how do i stop it when the if statment is true ?

I am using setInterval(fname, 10000); to call a function every 10 seconds in JavaScript. Is it possible to stop calling it on some event?   I want the user to be able to stop the repeated refresh of data.


If I have $~18~$ cards: $~1,~1,~1,~2,~2,~2,~3,~3,~3,~4,~4,~4,~5,~5,~5,~6,~6,~6~$ how many different hands of $~9~$ cards are possible. The order of the cards does not matter.  So $~1,~4,~5,~3,~6,~2,~4,~2,~2~$ is the same as $~1,~2,~2,~2,~3,~4,~4,~5,~6~$ etc so they should not be counted as different hands.  I've looked everywhere but I cannot find any relevant information which could help me. I can only find either answers for simpler questions or answers for incredibly harder questions when I looked and the answer (to me) doesn't seem obvious.  Edit: This question is similar though subtly different from the 10 cards out of a super deck as in this question the size of the hand exceeds the number of duplicate elements making it a much more complex question.

I have the following problem from book "Introduction to Probability", p.32     A certain casino uses 10 standard decks of cards mixed together into one big deck, which   we will call a superdeck. Thus, the superdeck has 52 · 10 = 520 cards, with 10 copies   of each card. How many different 10-card hands can be dealt from the superdeck? The   order of the cards does not matter, nor does it matter which of the original 10 decks   the cards came from. Express your answer as a binomial coefficient.   Hint: Bose-Einstein.   My solution:  Because the number of cards of each type in the superdeck (10) is not less than the size of the hand (10), and thus not limiting, it's the same as sampling with replacement where the order does not matter,  so the number of possible 10-card hands would be $\binom{52+10-1}{10}$.  Is my thinking correct?


I have a 16GB USB Flash Drive that is partitioned into two different sizes. The first partition contains a bootable version of Ubuntu, the second partition is for general saving of files.   Windows will only recognise the first partition. I have tried using  but this breaks the bootable partition. Disk Management recognises the second partition but does not allow me to do anything with it.  Is there a way to make both partitions accessible by Windows and keep the USB disk bootable?

I've got a USB stick with multiple Partitions on it (FAT32 (active), FAT32, Ext2, but that's another story) and it seems like that my Windows XP can only mount the first partition of the stick. If I try to mount the second one using the volume manager it tells me that I need to make it active and reboot...is it really that limited or am I just missing something here?  Partitions:   FAT32, System Rescue CD, bootable and active FAT32, some tools ext2, some data (I know that I need extra drivers, etc., but that's not asked here)


In this example:  The instrument can be used to apply pressure to the subject. The instrument can be used for applying pressure to the subject.  Are both correct? Are there any nuances between the two?

Someone edited my message on StackOverflow, but it really bugs me out.  I'm not sure what's wrong with it:   As you see, the bigger the circle becomes, the more vertices I need for hiding the straight lines. As you see, the bigger the circle becomes, the more vertices I need to hide the straight lines.   The latter (corrected) sentence just bugs me out for some reason. It would sound better if there was a comma after the word "need", perhaps, but I guess that would be even worse in means of grammatical correctness.  Can someone explain why is the first sentence bad and the second sentence correct? And could there even be better solution to fix the first sentence?


So I installed Ubuntu to use on my Chromebook by Crouton. I am using the Gnome shell because this is what I am learning in class. My problem is, I cannot upgrade it and am stuck at 16.04.6. I do not have much in the way of apps, to include an update manager. I installed my class version onto a virtual machine on another laptop but really want to use this Chromebook. The versions are not the same, that much is apparent just by looking at the windows and such. Is there a way to update it to 18.04? I tried the sudo apt-get update command from the terminal but had no luck, nothing was upgraded and nothing was installed. Please help

What are the different ways I can use to upgrade Ubuntu from one release to another?


I'm making a pet project with java GUI (netBeans) and while I was using ant, images worked properly. But I changed to maven since I don't know how to do tests work in ant with NetBeans. And the issue that I've encountered now with Maven is that image Icons keep creating this Exception.  I have this autogenerated code that creates buttons, actionEvents, listeners etc.  As I said, everything worked in ant but in maven it doesn't anymore. I'm using NetBeans. INeither do I understand exactly what to do with pom.xml, nor I know if I should put icons in another folder instead of "E:[...]\LeagueOfPokemon\src\main\java\icons". I don't mind ant or maven, I just want something that allows me to make tests and shows images. If someone knows what should I do please tell me.

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


I have a server (2 x E2620, 32 GB RAM, Debian 6 Linux us-fw 2.6.32-5-amd64 #1 SMP Mon Feb 25 00:26:11 UTC 2013 x86_64 GNU/Linux, 10G Intel Ethernet Card). It has an Nginx proxy server inside. Idea is to use it as a frontend against DDoS attacks. Currently, if faced to a 500kpps spoofed SYN flood, it becomes almost unresponsive. I've already tried syncookies and various sysctl parameters. Even if a half-open connection timeout is 1 second, it is enough to fill up any buffers. Any ideas how to harden it against spoofed syn floods? Maybe, some hardcore configs or fw rules?

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


Normally, if I'm too slow to contribute to closing a question in the CV queue, the error message is pretty reasonable: "This question is already closed. Please refresh the page." (Or words to that effect.)  Recently, though, at least on MSE, the error message in those cases is completely wrong. It tells me I can only open the close dialog every 3 seconds. While true, that's utterly irrelevant and entirely misleading.

Steps to reproduce:   Open two questions (with answers, in this case) in different tabs in the same browser Flag an answer to one (might not be needed, but it's what I did, so I'm including it) Someone else (might need a diamond for this) deletes an answer to the other Without reloading the second tab, try opening the flag dialog on the now deleted answer   Environment: Firefox 46.0.1 on up-to-date Windows 8.1.  Actual result: The UI responds with a message stating that I am opening the flag dialog too quickly.  Expected behavior: (A) The flag dialog should open, as happens after I reload the page and click "flag" again. Alternatively, (B) a message should be displayed saying that the answer is ineligible for flagging. If the user doesn't have the reputation necessary to see deleted posts, always do (B).  Something like this, shamelessly borrowed from :


If one travels in a spaceship at speed V, the time elapsed for the traveller relative to an observer on earth is dilated by,  $$ t' = t(1 - v^2/c^2)^{1/2} $$  Does this mean that a space traveller, who gradually accelerated to a speed very close to the speed of light can then travel 10 billion light years in a few minutes?  Relative to the travelling observer, does this mean that effectively there is no speed limit? Even though this can be translated as a space contraction, what difference does that make - the traveller effectively travelled 10 billion light years in say 6 minutes - meaning an effective speed of 100 billion light years per hour (876 trillion times the speed of light).   Does this mean that time travel into the future is possible? Would it be possible for a traveller making a round trip away and back to earth to travel to the year 3000 in 5 years?

It has already been  how fast a probe would have to travel to reach Alpha Centauri within 60 years.  NASA has done  into a probe that would take 100 years to make the trip.  But I am interested in this question from a slightly different perspective.  I would like to know how long the trip from our solar system to Proxima Centauri would take for both a ship and for an observer on Earth while accounting for the effects of general relativity on a .  The following assumptions may be made:   The ship starts and ends at 0 km/s relative to the Earth observer. The ship experiences a constant force of acceleration of 20 g until the half-way point and then a constant force of deceleration of 20 g until the destination. The path traveled is such that accleration is in only one spatial direction. The distance traveled is 4.25 light years.   Calculate (accounting for general relativistic effects):   Time of trip for Earth-based observer. Time of trip for ship-based observer. Maximum speed.   You don't need to consider mass, or life-support systems, or method of propulsion; I am really only interested in the effects of relativity on the perceived time of the trip.


As we know, Total number of permutations of the digits 12345 is 5!.  Well, I am looking for another interesting fact. How many permutations among them are in the way that no digit is in its original position?  (For example, 54231 is one of such ones, where all the digits are in different positions from the original permutation 12345)  Thanks in advance. :-)

I am trying to figure out how many permutations exist in a set where none of the numbers equal their own position in the set; for example, $3,1,5,2,4$ is an acceptable permutation where $3,1,2,4,5$ is not because 5 is in position 5.  I know that the number of total permutations is $n!$. Is there a formula for how many are acceptable given the case that no position holds its own number?


I am trying to automatically open a Word Document in Python. I am very new to programming and I heard this site helped people who had trouble with it.  I have looked at various questions and have found this:  DummyFile = path_to_docx with open(DummyFile) as f:     source_stream = io(f.read()) document = doc(source_stream) source_stream.close()   But when I run it, I get:   UnicodeDecodeError: 'charmap' codec can't decode byte 0x90 in position 74: character maps to <undefined>   It seems that this code is not what I want. I believe it is trying to read my document and put it into a variable. Not what I want. I want the command, that when executed, will open the word document in Microsoft Word  Expected Result:  Word Document opens in Microsoft Word, as can be seen here:

I need to be able to open a document using its default application in Windows and Mac OS. Basically, I want to do the same thing that happens when you double-click on the document icon in Explorer or Finder. What is the best way to do this in Python?


Given that  $a> 1$, $\alpha \in \mathbb{R} $,then  find $$\lim_{x\rightarrow \infty } \frac{a^x}{x^{\alpha}}$$ My attempts : $\frac{a^x}{x^{\alpha}} \le \frac{1}{x^\alpha}$ now  i take $\lim_{x\rightarrow \infty } \frac{1}{x^{\alpha}} = \frac{1}{\infty} = 0$ Is its correct ?? thanks  in advance

In other words, how to prove:  For all real constants $a$ and $b$ such that $a > 1$, $$\lim_{n\to\infty}\frac{n^b}{a^n} = 0$$  I know the definition of limit but I feel that it's not enough to prove this theorem.


I want to do something like this printf("%d,%d",array[c], array[c+1]), with only one variable that increases in every iteration. I wrote the following code, and I expected "1,2" to stdout, I was wrong:  #include <stdio.h> int main() {     int c = 1;     printf("%d,%d",c++,c++); /* 2,1 */     //printf("%d,%d",c,c++);   /* 2,1 */     //printf("%d,%d",c++,c);   /* 1,2 */ }   If I try doing printf("%d,%d",c++,c) and  printf("%d,%d",c,c++), I can see that there is no defined order of execution of the "c++" statements.  Could somebody explain how the code I wrote compiles to ? And why and how does it change according to the position of the "c++" statements.

Can it be assumed a evaluation order of the function parameters when calling it in C ? According to the following program, it seems that there is not a particular order when I executed it.   #include <stdio.h>  int main() {    int a[] = {1, 2, 3};    int * pa;      pa = &a[0];    printf("a[0] = %d\ta[1] = %d\ta[2] = %d\n",*(pa), *(pa++),*(++pa));    /* Result: a[0] = 3  a[1] = 2    a[2] = 2 */     pa = &a[0];    printf("a[0] = %d\ta[1] = %d\ta[2] = %d\n",*(pa++),*(pa),*(++pa));    /* Result: a[0] = 2  a[1] = 2     a[2] = 2 */     pa = &a[0];    printf("a[0] = %d\ta[1] = %d\ta[2] = %d\n",*(pa++),*(++pa), *(pa));    /* a[0] = 2  a[1] = 2 a[2] = 1 */  }


I need to grant all the privileges of a user (say 'AAA') to another user (say 'BBB').  Is there such an Oracle command (11.2.0.3.0)?

We'll be having external auditors coming over to perform a review on our Oracle database. They will be running a tool to perform the review and for that, they require a user ID that can connect to the database and grab information from it.  We have an existing user in the database for this. However, it is a production ID and we cannot afford to have it locked out. We would like to clone / duplicate this ID including its roles and rights.  Is there a way we can do so in Oracle?


As mentioned in the title. I’m trying to solve this problem by estimating $1+1/2+…+1/n$:$$1+\frac{1}{2}+…\frac{1}{n}=\ln(n)+\gamma+o(1)$$ Where $\gamma=0.57721...$ is Euler–Mascheroni constant. Then we get $$\sum_{n=1}^\infty (1+\frac{1}{2}+…\frac{1}{n})\frac{\sin{nx}}{n}= \sum_{n=1}^\infty \frac{\ln n\sin{nx}}{n}+ \gamma\sum_{n=1}^\infty \frac{\sin{nx}}{n}+ \sum_{n=1}^\infty \frac{\sin{nx}}{n} o(1)$$ I have problem continuing because I do not know how to handle the first term and the third term of RHS. P.s. I already know that $\sum_{n=1}^\infty \frac{\sin{nx}}{n}$ is convergent due to Dirichlet’s test.

For what values of $a$ does $$\sum_{n=1}^\infty \left( 1+\frac12 +  \dotsb + \frac1n \right) \frac{\sin (na)}{n}$$ converge?   To my thinking, $$f(n)=\frac{\left( 1+\frac12 +  \dotsb + \frac1n \right)}{n}$$ will behave like $\frac{\log n}{n}$, which is not convergent, but certainly has terms going to zero (eventually monotonically). By Dirichlet's test, $$\sum_{n=1}^\infty f(n) \sin(an)$$ will converge provided that the partial sums of $\sum_{n=1}^\infty \sin(na)$ are bounded, which they always are. So it should converge for all $a\in \mathbb{R}$.  Would appreciate anyone pointing out mistakes in this reasoning. Thanks


I am confused a little bit. I would like to swap 2 directory in the apache2 config files with the sed program.  APACHE_CONF=/etc/apache2/apache2.conf FULL_DIR=/home/$USER/new DEFAULT_DIR=/var/www/html`   This works fine:  sudo sed -i.bak 's|'$DEFAULT_DIR'|'$FULL_DIR'|' "$APACHE_CONF"   These are not (these don't have error, just do nothing):  sudo sed -i.bak 's/"$DEFAULT_DIR"/"$FULL_DIR"/' "$APACHE_CONF" sudo sed -i.bak 's/\"$DEFAULT_DIR"/\"$FULL_DIR"/' "$APACHE_CONF"   Can anybody explain why don't these work and why does the first one work?

I often see tutorials on the web or posts on this site which make heavy use of the following characters at the command line. Often it seems that they are used for pretty similar purposes. What are the differences between them when used on the command line or for shell programming? For what purpose do I use which of them?  " " double quotes  ' ' single quotes  ` ` backticks


I'm having a bit of trouble thinking of a good way to describe/search for this, so bear with me if it's a duplicate.  I recently realised that in the iOS app, when you click a link and a page is opened in the included browser, apart from closing the browser by hitting the “OK” button at the top (which is not always visible), swiping from left to right to ‘go back’ has the same effect.  However, when I close the browser in this manner, the question that I return to remains frozen for about five seconds, and even after it unfreezes, the “<” button to return to the previous question or question list does not work. It looks normal, but when I click on it, it changes to being greyed out and does nothing.  If I close the browser with the “OK” button, this does not happen: the question does not freeze, and the “<” button works as it should.  Is this a known bug?  (iOS 9.2.1, up to date; SE app version 1.4.3.7.)

iOS app 1.4.3, iOS 9.2.1  While viewing a post, the app somehow ended up in a state where it refuses to do much of anything.  What does work:   Swipe-scrolling vertically Jumping to the previous / next post using the up / down buttons    Everything else, though, has no effect:   Swipe-scrolling horizontally will not return to the previous view Tapping on a code block will not zoom to code-block view Tapping Delete button to delete a post will show a confirmation dialog, but saying yes will not cause deletion The Add Comment button brings up the text field, but I cannot type anything in it; I can only dismiss it None of the other buttons (Share, More, etc.) do anything Cannot view user profiles or revision history Tapping on links in a post or comment will not show a web page Tapping on a tag shows some visual feedback with a temporary color change, but doesn't do anything else   I still receive push notifications, but tapping on them doesn't take me anywhere.


How to search the topics in Stackoverflow by filtering with 2 tags. For Example , I was able to search the questions with single tag like playframework, but if i want to search with tags like playframework, scala, internalization etc,  Can you please suggest me? It will be helpful to me in learning the concepts from stackoverflow

How do I search for questions with specific tags?       For more information about searching, see "" in the .


I want to make screencast videos and record audio externally. What video editing software should I use? This is for an online class in introductory logic that I'm terribly late putting together.  To clarify: I want to record external audio, not internal. I want to highlight lines in a PDF while talking about the material.  I tried recordMyDesktop but it doesn't seem to have an external audio option.

Is there a way to record my screen, as well as the internal audio? Like, if I were recording a game, it would record the screen, and the sounds from the game.


I was solving a problem in real analysis where the author used the below to support his argument. $$\lim_{n\to\infty} \frac{2^{n}}{n!} = 0$$ How does the above limit hold ?

Why is     $$\lim_{n \to \infty} \frac{2^n}{n!}=0\text{ ?}$$   Can we generalize it to any exponent $x \in \Bbb R$? This is to say, is     $$\lim_{n \to \infty} \frac{x^n}{n!}=0\text{ ?}$$     This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


[Duplicate question:  see  for answer ("No, don't qualify the attributes")]  This is my first time working with XML namespaces, and I want to make sure I'm doing this right.  Strangely, for such a simple thing, I can't find anything on SO that addresses the question:  I've got a namespace-qualified XML element with some attributes.  Do the attributes need to be qualified too, or does the scope extend to them?  <foo:tag value="bar" />   or   <foo:tag foo:value="bar" />

I'm trying to understand how namespaces work in XML. When I have an element like foo:bar, the attributes will often not have namespaces on them. But sometimes they will. Are the attribute in the namespace of the element, even when the default namespace has been declared? Looking over the xsd for xhtml it seems the attributes are part of the schema and should be in the namespace for xhtml, but they are never presented that way...


While using a delay in a loop i am passing the loop index like below  for (var t = 0; t < 3; t++) {     var t1 = {};     t1['a'] = String(t);     setTimeout(function () {         console.log("Step ", t1);     }, 1000); }   Edit : Here t1 is a local variable i.e. it is scoped for one iteration only.  And the console output is   Step  Object {a: "2"} Step  Object {a: "2"} Step  Object {a: "2"}   And when i wrap the for loop content with a function like below  var func = function (index) {         var t1 = {};         t1['a'] = String(index);         setTimeout(function () {             console.log("Step ", t1);         }, 1000);     }; for (var t = 0; t < 3; t++) {     func(t);    }   The console output is   Step  Object {a: "0"}  Step  Object {a: "1"}  Step  Object {a: "2"}   So, in first example the value is passed by reference and in second it is not.   Can anyone like to explain this behavior.

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


I would like to know if it is possible to fill a mesh, using it as a bounds area to then fill it entirely with a polygon(the shape) mesh.  The idea is I’ve blocked out a level design. But i want my level to be all polygons just like Vavle’s the lab archery level.    I have made various block sections of the level and now want to make it look like the section is made up of multiple individual polygon meshes. So I want them all touching but would still like to modify them individually. For example I am wanting to add details to the outside polygons  Edit: linked solution doesn't work for a hexagon. The rigidbodies never settle in the animation.

I'm trying to find a way to achieve an extruded version of what the image below shows without having to manually scale every cylinder.  I tried particle systems (hair, both vertex and face modes), but I seem to be unable to reach a satisfying compromise between gaps and intersections. My cylinders, in an ideal world, should not intersect at all, and every cylinder must be touchng at least another one.  Here is my reference image:   Any ideas?  Thanks in advance :)


I am trying to install software-properties-common, but I am getting this error:  The following packages have unmet dependencies: software-properties-common : Depends: python-gi but it is not going to be installed E: Unable to correct problems, you have held broken packages.   I actually tried to install this python-gi dependency, but getting again an error:  The following packages have unmet dependencies: python-gi : Depends: libgirepository-1.0-1 (>= 1.29.0) but it is not going to be installed Depends: libglib2.0-0 (>= 2.31.8) but it is not going to be installed Depends: gir1.2-glib-2.0 (>= 1.31.0) but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Ubuntu version  Distributor ID: Ubuntu Description:    Ubuntu 14.04.4 LTS Release:    14.04 Codename:   trusty   EDIT Result of apt-cache policy software-properties-common python3-gi python-gi  software-properties-common:   Installed: (none)   Candidate: 0.82.7.7   Version table:      0.82.7.7 0         500 http://mirror.symnds.com/ubuntu/ precise-updates/main amd64 Packages      0.82.7.5 0         500 http://mirror.symnds.com/ubuntu/ precise-security/main amd64 Packages      0.82.7 0         500 http://mirror.symnds.com/ubuntu/ precise/main amd64 Packages python3-gi:   Installed: (none)   Candidate: 3.2.2-1~precise   Version table:      3.2.2-1~precise 0         500 http://mirror.symnds.com/ubuntu/ precise-updates/main amd64 Packages      3.2.0-3 0         500 http://mirror.symnds.com/ubuntu/ precise/main amd64 Packages python-gi:   Installed: (none)   Candidate: 3.2.2-1~precise   Version table:      3.2.2-1~precise 0         500 http://mirror.symnds.com/ubuntu/ precise-updates/main amd64 Packages      3.2.0-3 0         500 http://mirror.symnds.com/ubuntu/ precise/main amd64 Packages

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


The  in my Network Profile is showing that I have a rep. of 3,728 in Economics Meta Stack Exchange. That's my rep. in Puzzling Stack Exchange and moreover I don't have an account in Economics Stack Exchange.  It's also not showing the graphs of sites where I have more than 200 rep.  I tried visiting some others' Reputation tabs too. For some it's consistent and for others it's again showing inconsistent data. For example, José Carlos Santos doesn't have an Internet of Things account but his  showing he has a rep. of 3,972 in IOT Meta SE.  This is his rep. in History of Science and Mathematics

Today I noticed that when I look at the reputation graph on my profile, I don't even belong to most of the sites it is showing. My highest reputation sites are not shown at all. This is me:  This is not me:


Can I shorten the sentence like this?  1- This is Peter, a student who is researching nuclear physics at a university .   2- This is Peter, a student researching nuclear physics at a university.

I went down yesterday to the Piraeus with Glaucon the son of Ariston, that I might offer up my prayers to the goddess (Bendis, the Thracian Artemis.); and also because I wanted to see in what manner they would celebrate the festival, which was a new thing. - The Republic of Plato.   Glaucon is the son of Ariston, right? I suppose it should be Glaucon who is the son of Ariston. Can we omit that?


A user profile on the site can be deleted via  in the settings. Is there a way to delete only a chat profile? If the user can’t do it by himself/herself, can the moderators?

The process of deleting a site profile is explained in Help Center and elsewhere. But I don't see any instructions for requesting the deletion of one's chat profile. (Why delete it? To disassociate self from chat content, for example. The chat profile may contain information that identifies the author.)   Should such requests be communicated to a moderator via a flag, or sent to the Team using contact us form, or ...?   The answer might be different in two scenarios:   There is still a site profile to which the chat profile is attached (the "parent" of chat profile). The parent no longer exists (for example, SO profile was deleted but chat.SO account still exists).


Okay here's the question:  Ubuntu 12.04 Precise will not shut-down it just Reboots again!  Its as simple as that. I have tried every command out there and not a single one of these commands works in grub or Ctrl + Alt + T or any other method suggested.   sudo shutdown -p now <-This does not work Type in terminal:   sudo -i (to get a root shell, sudo gedit is not recommended) gedit /etc/default/grub   Find the line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"   Change this to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=force" Save the file and close the file. Finally, in terminal: update-grub exit (to end the root shell) <-This does not work  sudo poweroff <-This does not work alt + F2 and type gksudo poweroff <-This does not work Code:   sudo gedit /etc/default/grub   --> remove quiet splash, then :  sudo update-grub   before trying to shut down again, run:  sudo apt-get install --reinstall ubuntu-desktop sudo dpkg-reconfigure -phigh -a  <-This does not work  halt or shutdown -h now <-This does not work sudo init 0 <-This does not work acpi=norq added to grub <-This does not work Typing shutdown or restart in Dash Home <-This does not work sudo shutdown -h 0 <-This does not work sudo halt <-This does not work sudo shutdown -h 0 <-This does not work   So lets try to figure it out together, lets solve it since no updates are coming in to fix it!

After two days of installation, strangely my Ubuntu machine is restarting instead of shutdown from both desktop GUI and command line.  sudo shutdown -h now sudo halt  # (doesn't shutdown, instead freezes on boot screen Plymouth)   I had force shutdown by powering off the machine.  This is not happening all the times.  I have been using Ubuntu for 6 months and never experienced this kind of problem.


I want to update a Text_Element with a newline or page break using ArcGIS Desktop 10.0.    Does anyone know the tag or syntax?

I ran across an issue the other day when I tried to use ArcPy's mapping module to edit rectangle text elements with newlines (\n) in an ArcMap document.  Here's what the output looked like:    Here's the code I used to generate that output.  The first column are rectangle text elements Text1, Text2, Text3 going down; the second column are "plain" text elements Text4, Text5, and Text6 going down.  import os import arcpy  HomeDir = r"C:\Desktop" arcpy.env.workspace = HomeDir  CurrentMXD = arcpy.mapping.MapDocument(r"C:\Desktop\TextTest.mxd") OutputFilename = r"C:\Desktop\TextTest.pdf" if os.path.exists(OutputFilename):     os.remove(OutputFilename)  for TextElement in arcpy.mapping.ListLayoutElements(CurrentMXD, "TEXT_ELEMENT"):     TextElementName = TextElement.name      String1 = "The quick brown fox jumped over the lazy dog.\nShe sells sea shells by the sea shore."     String2 = "The quick brown fox \njumped over the lazy dog.\nShe sells sea shells by the sea shore."     String3 = "The quick brown fox jumped \nover the lazy dog.\nShe sells sea shells by the sea shore."      if TextElementName == "Text1":         TextElement.text = String1     if TextElementName == "Text2":         TextElement.text = String2      if TextElementName == "Text3":         TextElement.text = String3     if TextElementName == "Text4":         TextElement.text = String1     if TextElementName == "Text5":         TextElement.text = String2     if TextElementName == "Text6":         TextElement.text = String3  arcpy.mapping.ExportToPDF(CurrentMXD, OutputFilename)   So far, it looks like the presence of the messed up text depends on whether the line is longer enough to wrap, and whether the line before the newline is longer than the line after the newline.  Any ideas about what could be going wrong?  Is there a workaround?  I could use plain text elements and worry about wrapping lines using Python, but I'm hoping I can figure something out.


If you know what a number mod two different primes is (3 and 2) in this case, how can you tell what the mod is of the two products?


I am having issues creating dirs using a variable in a script. Ex:  read user mkdir $user{01..10}   Interestingly, it will work like this:  read user mkdir {01..10}$user   Any way to get around this, or what am I missing?  Thanks

I can write  VAR=$VAR1 VAR=${VAR1} VAR="$VAR1" VAR="${VAR1}"   the end result to me all seems about the same. Why should I write one or the other? are any of these not portable/POSIX?


Hi!  Is this card working with Ubuntu. Is there any driver? When I installed Ubuntu 12.04 there was a black screen.  Thx, Akitoru

I just ordered the Nvidia GTX card. I have a dilemma, though. Should I keep using the driver which is available in "additional drivers" in Ubuntu, or should I install the driver from the Nvidia site?  So which driver is the best for me?


Sometimes an icon is shown in the left bottom corner of the lock screen. Sometimes I can see some logic in it - when I plug the earphones, then the streaming radio app icon appers. I cannot start the app tapping the icon though. But sometimes an icon is just there without any visible connection to my actions, for example the Stack Exchange app icon:    Why is that? What is it useful for and what can I do with them? If I tap them nothing happens.

On the Lock Screen, Proactive Siri can suggest apps. If my iPhone detects I'm in the car, it correctly shows a Maps icon in the lower left corner on the lock screen.  Under iOS 9, you could swipe up to open that app.  How do you open the app in iOS 10? Swiping up doesn't work.  Note: I am using a Force Touch enabled phone, but for completion's I'm also wondering how this works on a non-force touch phone.


I want to simulate a flow using the Euler equations. For this reason I'm wondering if there's a modified version of the Euler equations.  At the moment my formula looks like this:  $$ \frac{\partial}{\partial t} \begin{pmatrix} \rho \\ \rho v_1 \\ \rho v_2 \\ \rho v_3 \\ \rho E \end{pmatrix} = -\mathrm{div} \begin{pmatrix} \rho v_1 & \rho v_2 & \rho v_3 \\  \rho v_1^2 + p & \rho v_1 v_2 & \rho v_1 v_3 \\  \rho v_2 v_1 & \rho v_2^2 + p & \rho v_2 v_3 \\  \rho v_3 v_1 & \rho v_3 v_2 & \rho v_3^2 + p \\  (\rho E + p) v_1 & (\rho E + p) v_2 & (\rho E + p) v_3 \end{pmatrix} $$  Since the state variables are all in combination with the density, I need a division to calculate the flow. So what I actually would like to get is something like this:  $$ \frac{\partial}{\partial t} \begin{pmatrix} \rho \\ v_1 \\ v_2 \\ v_3 \\ E \end{pmatrix} $$   Can someone help?

I'm working on the calculation of the  with the . Unfortunately I'm not allowed to do a division. So I'm wondering if there's a form which does not need a division.  At the moment the Euler equations look like this:  $$ \frac{\partial}{\partial t} \begin{pmatrix} \rho \\ \rho v_1 \\ \rho v_2 \\ \rho v_3 \\ \rho E \end{pmatrix} = -\mathrm{div} \begin{pmatrix} \rho v_1 & \rho v_2 & \rho v_3 \\  \rho v_1^2 + p & \rho v_1 v_2 & \rho v_1 v_3 \\  \rho v_2 v_1 & \rho v_2^2 + p & \rho v_2 v_3 \\  \rho v_3 v_1 & \rho v_3 v_2 & \rho v_3^2 + p \\  (\rho E + p) v_1 & (\rho E + p) v_2 & (\rho E + p) v_3 \end{pmatrix} $$  As you can see, I first need to calculate $\frac{\rho v_1}{\rho}$ to get $v_1$ so I can calculate e.g. $\rho v_1^2$


I have historically been able to create SFDX projects with no issue but have just began to receive the following error on creation:  Starting SFDX: Create Project  16:16:37.144 sfdx force:project:create --projectname HelperJS --outputdir c:\Users\mhandler\Desktop --template standard ERROR running force:project:create:  Command failed with exit code 1: npm root -g --prefix c:\Users\mhandler\Desktop\.yo-repository --loglevel error 'npm' is not recognized as an internal or external command, operable program or batch file. 16:16:43.741 sfdx force:project:create --projectname HelperJS --outputdir c:\Users\mhandler\Desktop --template standard  ended with exit code 1   Steps to Replicate:   SFDX: Create Project 'Standard' ProjectName: 'HelperJS' Tried Multiple Folders Including Desktop & Sub-folders   Any assistance would be greatly appreciated. I am unable to create an SFDX Projects now.  Thanks,

I am getting the error "'npm' is not recognised as an internal or external command" while creating project in VS code using Salesforce CLI. Don't know what I am missing out. Can anyone guide me.


Does it mean "user"? I attempted to navigate to  usr via  cd however I received No such file or directory error.  I could only find  in Russian the following information:      "/usr (от англ. User System Resources — системные ресурсы   пользователя) — каталог в UNIX-подобных системах, содержащий   динамически компонуемые программы, файлы пользователей и программы,   устанавливаемые вручную. В соответствии с FHS, монтируется на корневую   файловую систему и должен содержать только не изменяющиеся программами   данные (то есть /usr в режиме эксплуатации может быть смонтирован в   режиме «только для чтения» без ущерба для функциональности)[1].      Традиционная система подкаталогов /usr/   Вторичная иерархия для данных   пользователя; содержит большинство пользовательских приложений и   утилит, используемых в многопользовательском режиме. Может быть   смонтирована по сети только для чтения и быть общей для нескольких   машин[2]. /usr/bin/"   However, I don't understand.    Translation of the quote:  /usr ( from English "User System Resources" ) - catalogue/directory in UNIX-like systems, containing dynamically combined programs, user files and manually-installed programs. In accordance with FHS, it is mounted on root filesystem and must contain only data which is not to be modified by programs (that is to say, /usr in operational mode can be mounted as read-only without loss of functionality)  Traditional system of subdirectories /usr/ Secondary hierarchy for user's data; contain most user's applications andutilities, used in multiuser mode. Can be mounted over network only in read-only mode, and can be shared between multiple machines.

In Windows there’re perhaps only a couple of important folders (by important I mean important in my logical picture of the Windows file system) in the installation drive (in my case C:\). Namely Program Files and Windows. I simply stay away from Windows folder and the “add remove program files” is good enough to handle the program files folder of Windows. Of course there’s a folder named Users where the users (who are not admins) can access only their folders.  Thus there’s a clear picture at some level in my mind of the Windows file system. In Ubuntu, when I reach the location /, there’s a huge list of folders, most of which I have no clue as to what they contain. The /bin folder seems to be the equivalent of the Windows folder in windows. The /usr folder seems like it’s the equivalent of the Users folder in Windows. But even the /home folder looks like it can fit the bill.  Please understand that I do understand, that Ubuntu (Linux) has a different character than that of Windows, i.e., there need not be exact equivalent of Windows functions, in Ubuntu. All I am looking for is a bit more clearer picture of the Ubuntu file system.   This question is a part of a bigger question which I am splitting up to make it more answerable. The original question can be found here:


I have declared at line 1-3 for the value to be in integer. But when running the code, it'll give me float value instead of integer unless I declare it: total = int(group_3 + group_2 + group_1) Is this because of Modulo? If so, any idea why? a = int(input()) b = int(input()) c = int(input())          group_1 = (((a % 2) + a) / 2) group_2 = (((b % 2) + b) / 2) group_3 = (((c % 2) + c) / 2)          total = (group_3 + group_2 + group_1) print(type(total)) print(total)

Is there a benefit to using one over the other? In Python 2, they both seem to return the same results:  >>> 6/3 2 >>> 6//3 2


I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


The result of df -h is like this:  Filesystem               Size  Used Avail Use% Mounted on udev                     3.9G     0  3.9G   0% /dev tmpfs                    797M   88M  710M  11% /run /dev/mapper/vgroot-root   25G   18G  5.8G  76% / tmpfs                    3.9G  106M  3.8G   3% /dev/shm tmpfs                    5.0M  4.0K  5.0M   1% /run/lock tmpfs                    3.9G     0  3.9G   0% /sys/fs/cgroup /dev/sda1                945M   75M  806M   9% /boot /dev/mapper/vgroot-home   15G   14G   56K 100% /home vmhgfs-fuse              239G  200G   40G  84% /mnt/hgfs tmpfs                    797M     0  797M   0% /run/user/999 tmpfs                    797M   64K  797M   1% /run/user/500   I see /home directory is 100% full, but don't know how can I enlarge it?  I tried resize2fs /home 50G and got     open: Is a directory while opening /home   Then I tried mount -o remount,size=50G /home but I got     mount: /home not mounted or bad option   Then I run gparted in the ubuntu client, the info is like this:  /dev/sda1   ext4        /boot  976MB /dev/sda2   extended           299GB   /dev/sda5 lvm2 pv     vgroot 299GB unallocated unallocated        1MB   This is for my vmware disk, in vmware, the Ubuntu's disk is set to 300G as the max size.  Should /home be listed here? Do I need to mount it?  sudo lvdisplay is:  --- Logical volume ---   LV Path                /dev/vgroot/root   LV Name                root   VG Name                vgroot   LV Status              available   # open                 1   LV Size                25.00 GiB   - currently set to     256   Block device           253:0    --- Logical volume ---   LV Path                /dev/vgroot/swap   LV Name                swap   VG Name                vgroot   LV Status              available   # open                 2   LV Size                4.00 GiB   - currently set to     256   Block device           253:1    --- Logical volume ---   LV Path                /dev/vgroot/home   LV Name                home   VG Name                vgroot   LV Status              available   # open                 1   LV Size                15.00 GiB   Read ahead sectors     auto   - currently set to     256   Block device           253:2    LV size is 15GB.  sudo pvdisplay:  PV Name               /dev/sda5   VG Name               vgroot   PV Size               299.04 GiB / not usable 0      Allocatable           yes    PE Size               4.00 MiB   Total PE              76555   Free PE               65291   Allocated PE          11264   pvscan is:  PV /dev/sda5   VG vgroot          lvm2 [299.04 GiB / 255.04 GiB free]   Total: 1 [299.04 GiB] / in use: 1 [299.04 GiB] / in no VG: 0 [0   ]   I need to increase the size of /home, but how?

How do I resize a LVM partition using system-config-lvm?  As per   I clicked on the partition and tried to resize, but got a pop-up error from system-config-lvm.     Logical volume is not mounted but is in use. Please close all applications using this device (eg iscsi).     What's the problem and how can I fix it?    See also .


My company has very restrictive IT policies. I am not allowed to install LaTeX and the company rules won't let IT install anything that doesn't appear on their list of safe software. I think I see a safe and legal workaround though. I have an application for viewing videos that can produce standalone executables. These standalone executables allow someone without admin rights to use a limited version of the video software just by placing the .exe file on their computer and opening it.  Has anyone created something similiar for LaTeX? Does anyone have any ideas for a good workaround? (Safe and legal)

I want to install a portable Tex Live in windows 10. But after searching online I just get this from .  The -portable installer option (or V command in the text installer or corresponding GUI option) creates a completely self-contained TEX Live installation under a common root and forgoes system integration. You can create such an installation directly on a USB stick, or copy it to a USB stick afterwards. To run TEX using this portable installation, you need to add the appropriate binary directory to the search path during your terminal session, as usual. On Windows, you can double-click tl-tray-menu at the root of the installation and create a temporary ‘tray menu’ offering a choice of a few common tasks, as shown in this . The ‘More…’ entry explains how you can customize this menu.  Any more instructions in detail? What should I do?


There seems to be an inconsistency in my inbox. There has been a message from a user (under the form of a @reply comment) that I can see under the post and in the "responses" tab in my profile, but it is not showing up in my inbox:    It seems the post in question has been quickly deleted, then undeleted (see ), so this is probably what caused the issue.

Looking under , I see:    Looking under my inbox on the top bar, I see:    (I believe only I, and perhaps mods, can see either of these screens - sorry about that)  Note the two I circled are different comments, neither showing up in the other display.  The one I encircled in my inbox is actually  (since it's a deleted post, 10k+ users only unfortunately), which may explain why it doesn't show up in my responses tab (I don't really care about that, and frankly this behaviour makes sense).  My question is - why does 's notification show up in my responses tab, but not my inbox?  Is it perhaps related to the deleted comment?


Let $f : \mathbb{R} \to \mathbb{R}$ differentiable be such that $$f'(x)=f^2(x)$$ for all $x$ and $f(0)=0$. Show that $f(x)=0$ for all $x$.   My attempt:  Notice that $f'(x)=f^2(x)\geq 0$, thus $f$ is increasing. Since $f(0)=0, f(x)\geq0\; \forall x \geq 0$. Since $f$ is differentiable, $f$ is continous, therefore given $1> \epsilon >0$, there exists $\delta<1$ such that for $x \in (-\delta,\delta)\implies f(x)<\epsilon<1.$ Take $x=\delta/2$. Then $f(x) = f'(c)\delta/2=f^2(c)\delta/2$. Then $f^2(c) \geq f(x)$. But since $c\in (-\delta,\delta)$, $0\leq f (c)<1 \implies f^2(c) \leq f(c)\implies f(c)\geq f(x)$. But $c<x$, therefore $f(c)\geq f(x)$ which means $f(c)=f(x)$. Therefore for all $y \in (c,x)$, $f(y)=f(x) \implies f'(y)=f^2(y)=0 \implies f(y)=0$. Where do I go from here?

Let $f:\mathbb{R} \rightarrow \mathbb{R}$ be a differentiable function such that $f(0) = 0$ and $f'(x) = [f(x)]^{2}$, $\forall x \in \mathbb{R}$. Show that $f(x) = 0$,  $\forall x \in \mathbb{R} $.  I first (unsuccessfully) tried using the Mean Value Theorem, but this is in the Integrals chapter so the solution probably involves them. Can't really see where integrals come in here though.  What I've got so far:   (i) Since $f$ is differentiable, thus it is continuous and, hence,  integrable. Therefore $f^2$ is also integrable and as $f'=f^2$, $f'$ is too.   (ii) $f' \geq 0$, $\forall x \in \mathbb{R}$


I want to calculate the integral which is dependent on the parameters $a$ and $b$ ($a,b \gt0)$.   $\int_{0}^{\infty} \frac {b \sin (ax) - a \sin (bx)}{x^2}dx$  This integral is solved in my textbook but I don't understand how and why  like this:  $ab \int_{0}^{\infty} \frac {b \sin (ax- a \sin (bx)}{abx^2}dx=ab \int_{0}^{\infty} \frac {1}{x} (\frac {\sin (ax)}{ax} - \frac { \sin (bx)}{bx})dx = ab \ln (\frac {b}{a})$  $f(x) = \frac {1}{x}$, ${}$ $\lim_{\to \infty} \frac {sinx}{x}=0$, ${}$ $\lim_{\to 0^+} \frac {sinx}{x}=1$  I just can't see it how they calculated it. Thanks.

How can I prove the Theorem of Frullani? I did not even know all the hypothesis that $f$ must satisfy, but I think that this are  Let $\,f:\left[ {0,\infty } \right) \to \mathbb R$ be a a continuously differentiable function such that $$ \mathop {\lim }\limits_{x \to \infty } f\left( x \right) = 0, $$ and let $ a,b \in \left( {0,\infty } \right)$. Prove that $$ \int\limits_0^{\infty}  {\frac{{f\left( {ax} \right) - f\left( {bx} \right)}} {x}}dx  = f\left( 0 \right)\left[ {\ln \frac{b} {a}} \right] $$  If you know a more general version please give it to me )= I can´t prove it.


Does an Ubuntu 14.04 server automatically perform smartctl condition monitoring? How can I check that it's happening properly? How can I be sure that I will receive an email when things start to go wrong?  If the answer to the first question is 'no', what is a recommended simple, straightforward way to set this running in the Ubuntu context?  Have smartctl setup defaults changed in newer LTS releases?  This is not a duplicate of : the output from sudo smartctl -a /dev/sda does not say when the last test was completed, and gives no information about the scheduling of regular SMART tests.  I am trying to find out what regular, scheduled testing is happening on my machine, to ensure if a problem arises, I can be confident it will be spotted by the system and reported.  SMART testing is one thing, but perhaps there are other things that I can  be using as well?

How can I check the SMART status of a drive under 14.04 and beyond? I've seen  but it doesn't seem to apply under 14.04 and later.


Using the crop package, we can easily add printer marks. I am look for .     I am wondering if there is a package for this?

A standard proof for press needs crop marks and color bars as below    With the package crop, the crop marks can be easily added.  But how about the color bar ?  Is there a way or a package to make it ?  An example is   \documentclass[b5paper,10pt]{article} \usepackage[utf8]{inputenc} \usepackage[cross,a4,center,info,axes]{crop}  \title{Test} \author{User} \begin{document} \maketitle \section{Fox} The quick brown fox jumps over a lazy dog. \end{document}


Seems like searching for the answer on Google just leads me to how to create make files and profiles.  I know how to do that. I also know how to install Drupal with drush.  But I want to install one of the many existing Drupal profiles, like Drupal Commons, Commerce Kick Start, etc. with drush.  I would have thought it would have been just an easy process to find the profile's makefile and run that. Drush will take care of the rest. But I can't find the repositories where these makefiles sits.  Some direction would be appreciated.

Am I right in thinking that the Drupal distributions that I can download from  are a standard Drupal core download with a load of other stuff added at /profiles?  Anyone know if there are any plans to create a dev branch of distributions that would automatically update the core version that the distribution is running on? Currently it seems that the distribution runs on whatever core version its developer has chosen.  And how can I use distributions with Drush? Is there an equivalent to drush dl drupal that will download a specific distribution?  And, finally, is there any difference between an install profile and a distribution?


I am a little bit confused about which is really the energy operator. During the lectures, the professor told us that the energy operator is simply the Hamiltonian $\hat{H}$ and that the eigenvalues represent the energy of the system. On Wikipedia [1], though, there is written that the energy operator is  $$ i \hbar \frac{\partial}{\partial t}. $$  On this website I rode that $\hat{H}$ and $\hat{E}$ are the same thing so now I do not understand which one is the right energy operator.  [1]

In the time-dependent Schrodinger equation, $ H\Psi = i\hbar\frac{\partial}{\partial t}\Psi,$  the Hamiltonian operator is given by  $$\displaystyle H = -\frac{\hbar^2}{2m}\nabla^2+V.$$  Why can't we consider $\displaystyle i\hbar\frac{\partial}{\partial t}$ as an operator for the Hamiltonian as well? My answer (which I am not sure about) is the following:   $\displaystyle H\Psi = i\hbar\frac{\partial}{\partial t}\Psi$ is not an equation for defining $H$. This situation is similar to $\displaystyle F=ma$. Newton's second law is not an equation for defining $F$; $F$ must be provided independently.   Is my reasoning (and the analogy) correct, or is the answer deeper than that?


I am trying to determine at what DPI a certain camera can shoot, namely  , however the technical specs at the official site do not give any details about it.   Is there a way to calculate the maximum possible DPI a given camera can shoot provided we have the sensor type and its number of pixels (just as the in the link above) ?

I have two cameras, a 6mpix Panasonic FZ8, and 14mpix Canon A2200.  When I compare shots from two cameras, one of differences I notice is dpi number that camera reports in JPG info:   FZ8 reports dpi=72 A2200 reports dpi=180   What physical meaning can these numbers have? I am at loss for guesses.    I am fairly familiar with notion of dpi in scanning and printing. I can calculate density of pixels on the sensor of the camera. But then, the linear density of pixels on the sensor will be hundreds times larger than number above. So what, if anything, does it mean?


If we repeat k, I think there is little chance for s to repeat since user's private key x is random which is also used to calculate s.

I recently stumbled across  about deterministic (EC)DSA again. There he states the following:     Note that $k$ must be generated uniformly in the $[1, q-1]$ range   (where $q$ is the subgroup order). Any information on $k$, even   partial (such as: values between $1$ and $2^{160}-q$ are twice as   probable than values between $2^{160}-q$ and $q$), can be exploited by   the attacker.   When asked for clarification on this,  with  which mentions that Bleichenbacher discovered the attack and mentioned it in private communication with the author.  Now the paper has a short paragraph (section 2.2), which basically states an approximate equation for the bias and says that     Bleichenbacher actually used it in order to approximate the secret key more   and more precisely with signatures.   Now my question: How does this attack work in a more detailed description? or formulated differently: How does one exploit this tiny bias to recover the secret key and how many signatures (ie oracle queries) are required for this along with what approximate computational effort (if it is non-negligible)?    The relevant section from the paper is (for your convenience):     The initial standard pseudorandom generator in DSA for $k$ was simply   a 160-bit pseudorandom number reduced modulo $q$. Bleichenbacher   observed that the probability of $k$ in the $[0, 2^{160} − q]$ range   have probability which is twice of the others. This leads to a bias      $$E\left(e^{\frac{2i\pi k}q}\right)\approx \frac{q  e^{i\pi\frac{N-1}q}}{\pi N} \times \sin\left(\frac{\pi N}q\right)$$      where $N=2^{160}$. Since $q \approx N$, this may be large depending on   the $\frac{\pi N}q$ angle. Bleichenbacher actually used it in order to   approximate the secret key moreand more precisely with signatures.


When I try sudo apt-get install ubuntu-desktop I get the error message: unable to locate package ubuntu-desktop. Where do I obtain the package? Or what am I doing wrong?

When I try to install any package through the command line, I get an error.   $ sudo apt-get install <package> Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package <package>   Can anyone help me on this?


Imra the wizard is cornered! Surrounded by multiple foes, she casts Thunderwave in an attempt to push her enemies back. One of them succeeds on the saving throw! Knowing that moving out of their range might trigger an attack of opportunity, can she cast Misty Step in the same turn? I'm asking this because the rules under Casting a Spell states that  A spell cast with a Bonus Action is especially swift. You must use a Bonus Action on Your Turn to cast the spell, provided that you haven’t already taken a Bonus Action this turn. You can’t cast another spell during the same turn, except for a cantrip with a Casting Time of 1 action.  Does the order of spells casted matter? The wording makes it seem like you can't cast a Bonus Action spell and then an Action spell, but you can do it the other way around.

When casting a spell as a bonus action, you can't cast another spell on the same turn except a 1-action cantrip - can the order be "reversed"? Can you cast a cantrip first as a bonus action, then any other spell? If not, would it be broken to allow it?  I'm thinking a Sorcerer casting a Quickened true strike, then casting a leveled spell requiring a touch attack. Seems like a great use of the cantrip + Metamagic feature, but it seems like it is not allowed.


Whenever I sudo apt-get update I get an error. Here are the errors from the log:    Err:13 http://ppa.launchpad.net/ehoover/compholio/ubuntu eoan Release    404  Not Found [IP: 91.189.95.83 80]     Err:14   http://ppa.launchpad.net/gnome-terminator/ppa/ubuntu eoan Release        404  Not Found [IP: 91.189.95.83 80]    Err:15   http://ppa.launchpad.net/pipelight/stable/ubuntu eoan Release          404  Not Found [IP: 91.189.95.83 80]     E: The repository 'http://ppa.launchpad.net/ehoover/compholio/ubuntu    eoan Release' does not have a Release file.     N: Updating from such a repository can't be done securely, and is    therefore disabled by default.     N: See apt-secure(8) manpage for repository creation and user    configuration details.     E: The repository 'http://ppa.launchpad.net/gnome-terminator/ppa/ubuntu    eoan Release' does not have a Release file.     N: Updating from such a repository can't be done securely, and is    therefore disabled by default.     N: See apt-secure(8) manpage for repository creation and user   configuration details.      E: The repository   'http://ppa.launchpad.net/pipelight/stable/ubuntu eoan Release' does   not have a Release file.      N: Updating from such a repository can't be   done securely, and is therefore disabled by default.      N: See   apt-secure(8) manpage for repository creation and user configuration   details.   also when I try for example sudo add-apt-repository ppa:openrazer/daily or adding any other repository, I get a similar error  Can someone help me solve this? there are some answers over the internet, but I'm a beginner, so I can't understand how to fix my specific problem and not similar problems... thanks in advance!

When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?


I have a light that is operated by two switches. One is upstairs, and the other is down stairs. How can I make the light work by either switch? Currently if I turn the light on down stairs, I cannot turn it off upstairs.   Please advise.

I have a 3 way switch that was wired incorrectly when the switches were replaced with a different color switch.  Is there a methodical way for me to identify which wires represent which piece of the system so I can correct the bad wiring?  Currently if switch 1 is on, switch 2 can turn light on or off.  If switch 1 is off, then switch 2 does nothing.


Show that $$\dfrac{3}{1\cdot2\cdot4}+\dfrac{4}{2\cdot3\cdot5}+\dfrac{5}{3\cdot4\cdot6}+\cdots+\dfrac{n+2}{n\cdot(n+1)\cdot(n+3)}\\=\dfrac{1}{6}\left[\dfrac{29}{6}-\dfrac{4}{n+1}-\dfrac{1}{n+2}-\dfrac{1}{n+3} \right]$$   Trial: I proceed in this way $$\dfrac{3}{1\cdot2\cdot4}+\dfrac{4}{2\cdot3\cdot5}+\dfrac{5}{3\cdot4\cdot6}+\cdots+\dfrac{n+2}{n\cdot(n+1)\cdot(n+3)}\\=\dfrac{1}{6} \left[\dfrac{18}{1\cdot2\cdot4}+\dfrac{24}{2\cdot3\cdot5}+\dfrac{30}{3\cdot4\cdot6}+\cdots+\dfrac{6n+12}{n\cdot(n+1)\cdot(n+3)} \right] $$Then stuck how to break $6n+12$ so that we get the following result.

$\frac{3}{1⋅2⋅4}+\frac{4}{2⋅3⋅5}+ \frac{5}{3⋅4⋅6}+...\text{(upto n terms)}$  The general term seems to be $$T_r= \frac{r+2}{r(r+1)(r+3)}.$$  I see no way to telescope this because the factors of the denominator of the general term are not in arithmetic progression.  Do I have to use something else? Or am I missing some easy manipulation?


I have Indian passport with a dependant visa. My husband has recently received a British passport and my baby is British by birth. We are planning to go to Paris.  Do I need a visa and if yes, what is the procedure and what documents do we need to provide?

My husband is a Sri Lankan national with a Sri Lankan passport. He holds an indefinite leave to remain in the UK (card). Our 3 kids and I have British passports, we are all going to go to France. Does he (my husband) need to apply for a Schengen visa before travelling to France?


Which is the correct one:     the big downside is the imperfect messages the user gets.        the big downside are the imperfect messages the user gets.   I am almost sure the second one is correct with "the messages" being the subject and "are the downside" the predicative nominal.

My fish's native habitat is rice fields. My fish's native habitat are rice fields.   Which one is correct? I'm pretty sure it's the first, since 'is' modifies 'habitat,' but it still sounds weird...


My not exposed MongoDB has hacked to ransom, my files stored on /home/mongo/store has deleted, i use foremost, ext4magic , extundelete , nothing is happening , backups on the same server are deleted too... I have only 1 earlier month backup, its not possible for me to announce that to my customers.  I try my last solution and cat /dev/md3 ( -> /home) and my data partialy encoded appear   Do you know how to decrypt encoded values ?  Thanks all to save me.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


Earlier Today, I had a conversation for physics and the teacher gave a question stating: Keys "A" and middle "C" were pressed which created a Frequency of 440 Hz, A tuning fork was also hit, what does it create. As a Musician, I understand that A and C does not make any sounds, and the fork is kind of useless. Would I be in the right to assume that it does not make beat frequency?

Consider 3 waves of frequency 101, 103, 106 hz, and of same intensity. What should be the beat frequencies?     Now I can calc it for 2 waves, and i know how to write the combined equation of the two. But the addition of a third causes lots of problems...the equation is getting cumbersome. Can you please help me here? I dug around online, and some responses were neglecting the third wave as it was too close to one of the waves. If I want to avoid that, is there any other solution?


I am a Tunisian citizen working in Greece and holding the blue paper. I am married to a Greek citizen and now waiting for the Residence permit. As far as I know, I am able to go back to my home country and other visa-free destinations (Turkey, Morocco etc). While I wait for my residence permit, am I allowed to travel to schengen countries if accompanied by my Greek partner? I appreciate your help :) Cheers!

I have requested for a French long term (Type D) student visa from a consulate in India. It's a national Type D visa and not a Schengen visa. My question is that can we still go to other Schengen countries on this visa? If not then can we get a Schengen visa from a consulate in France?


I have been looking for a book about a group of teens with superhuman abilities. It is centred on a boy that has yellow eyes that can see into the future for a few seconds. I can't remember anything else about the book.

I read a YA novel in the early 2000s that I think takes place on Earth some time in the future. The human race has been enslaved by some other race, possibly aliens. If I remember correctly, humans were kept as slaves for some purpose and then exterminated at age 16, and I think some girls were kept to breed.  I remember scenes of a band of teenagers walking around sewers fighting these aliens who bled a blue "ichor." The only thing I distinctly remember about the book was that it was the first place I saw the word "ichor."  This is a pretty sorry description; but does anyone have a clue what this book was?


Dirichlet's Approximation Theorem shows how it is possible to find a rational approximation as close as required to any real number. Has it been proved whether there always exists a ratio of two primes as close as required to any real number?

Consider the closed interval $[0,1]$, there is $\frac{2}{3} \in [0,1]$ where $p=2$ and $q=3$. Similarly consider $[2,3]$, one can have $\frac{5}{2} \in [2,3]$ where $p=5$ and $q=2$. Does every interval of the form $[a,b]$, where $a,b \in \mathbb{R}$ contain a rational of this kind. If yes, how can we prove it?


I saw a lot of strange behaviours handling float numbers, but I don't know why that one occurs and how to avoid it...  With PHP on Windows, dividing 1136 by 100 returns 11.359999999999999:  echo (1136 / 100); //11.359999999999999   Why is that?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


My Lenovo P50 can't boot Linux.  I have Windows 10 installed on my SSD (with BitLocker -- I tried deactivating that before Linux installation, without any success). I used its Disk Manager to split the main SSD in two, and the second HDD also in 2. Then I booted on my USB stick and installed my Linux distribution (tried several versions of Ubuntu up to 18.10 & Mint up to 19.1) choosing SSD for /, HDD for /home and /dev/sda (SSD) for grub. The installation process works OK. Live Linux works perfectly fine, but when I'm rebooting the laptop hangs on a grub prompt. The only option I found so far is exit which then brings me to a BIOS boot menu where I can select between Windows Boot Manager, Linux Xxx and any other bootable device (my USB stick, etc.).  If I choose Linux Xxx, it turns to a black screen and goes back to that grub prompt. If I choose Windows... it boots fine.  Where could the problem be? What kind of grub command or option could I try? Where should I look for eventual logs? How can I "debug" or provide you with more details so we can fix the problem?  FYI, this is not a duplicate of "". I am booting with EFI, I have an ESP (), I'm using GPT.     grub2 is launched but in "prompt" mode. And none of the options I tried except "exit" are offering any solution. Lately, I tried to run boot, but it complains that I must first load the kernel. I have no idea about how to do this.  I assume there is also something to do with bcdedit, but I'm not very familiar with it and I'm afraid I could break the entire system messing with it.

First some background: I have dual-boot Windows 7 / Ubuntu 13.04 on Lenovo laptop. As I did the installation about 1.5 years ago and was then even more un-savvy linux user than I am now, I can't recall everything I did to get both OSes up and running. However, I do remember that it was quite troublesome procedure (running boot-repair at least once).  Now I'm considering trying another linux distro in addition to Ubuntu (most likely Arch), and this time I'd like to do it in a way that I have an idea what I'm doing (and possibly learn more about 'inner workings' of linux distros).  So that's enough for the background. Now my question is: How do I get information on what is my current grub / boot-loader configuration?  This seems to be first and quite separate issue to consider before even dreaming about installing a third OS and more advanced messing with partitions and boot.


I've seen the screenshots from  and noticed that when a mod deletes question-OP's comments, the mod's name gets the blue-OP-box too:        .  rolfl is certainly not the OP of that question, so their name should be wrapped in the box in such cases.

As they say, a picture is worth a thousand words:    The moderator here is not the original poster, but on the comments by the aforementioned OP, his name has the OP background. On the other comments, he (correctly) doesn't.


I added a key like this:  wget -q -O - https://jenkins-ci.org/debian/jenkins-ci.org.key | sudo apt-key add - sudo sh -c 'echo deb http://pkg.jenkins-ci.org/debian binary/ > /etc/apt/sources.list.d/jenkins.list'   Now I want to remove this key. How can I do that? I don't know where it got added and how does it look like.  When I do sudo apt-key list it prints out few things on the console. Not sure which one is related to what I did above?  david@machine:~$ sudo apt-key list /etc/apt/trusted.gpg -------------------- pub   1024D/437D05B5 2004-09-12 uid                  Ubuntu Archive Automatic Signing Key <master@ubuntu.com> sub   2048g/79164387 2004-09-12  pub   1024D/FBB75451 2004-12-30 uid                  Ubuntu CD Image Automatic Signing Key <image@ubuntu.com>  pub   4096R/C0B21F32 2012-05-11 uid                  Ubuntu Archive Automatic Signing Key (2012) <master@ubuntu.com>  pub   4096R/EFE21092 2012-05-11 uid                  Ubuntu CD Image Automatic Signing Key (2012) <image@ubuntu.com>  pub   1024D/D50582E6 2009-02-01 uid                  Kohsuke Kawaguchi <kkiu@kyterty.org> uid                  Kohsuke Kawaguchi <kyterty.iuytre@sun.com> uid                  [jpeg image of size 3704] sub   2048g/10AF40FE 2009-02-01  /etc/apt/trusted.gpg.d//pubring.gpg ----------------------------------- pub   2048R/06634014 2013-01-26 uid                  OSP Team <IET-OSP-IUY@host.com> sub   2048R/732F28E7 2013-01-26

I don't need the key in my server's keyring anymore. Is it possible to remove it? I added the key using this command:   curl http://repo.varnish-cache.org/debian/GPG-key.txt | apt-key add -   Thanks for helping


I need to calculate age in php.  I use this solution:  $birthdate = '1986-09-16';  $_age = floor( (strtotime(date('Y-m-d')) - strtotime($birthDate)) / 31556926);   from   Everything works fine, but for example if  $birthday = '1194-01-06' or   $birthday = '1900-01-01'  result is always 44.   if $birthday = '1910-11-09' everything is fine again and result is 103. Why?  Note: I don't want to use diff() function, because of some issues.  EDIT:   Earlier i had problems with diff(), some      Warning range()   showed during processing and after refreshing of website everything was fine again... i could not find solution to fix it and somewhere i read that using of diff() could cause it. So i tried other solution and it worked... until now.   Finally I used this solution:  $birthDate = from database in timestamp format... $birth = new \DateTime($birthDate); $now = new \DateTime; $age = $now->diff($birth)->y;   and I randomly get  Warning  range(): step exceeds the specified range   again.

I have two dates of the form:  Start Date: 2007-03-24  End Date: 2009-06-26   Now I need to find the difference between these two in the following form:  2 years, 3 months and 2 days   How can I do this in PHP?


My current laptop configuration is as below: Memory - 1.9Gib Processor - Intel Pentium(R) cpu A1018@2.10Ghz x 2 Graphics -:Intel Ivy bridge Mobile x86/MMX/SSE2 Disk - 245 GB When I increase my ram memory to additional 2GB a sum of 4GB ram does it sufficient to run Ubuntu 20.04 LTS latest OS?

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


I need to include many JPG images in a LaTeX document. They are quite "heavy" (many MBs each), but in my document they will be printed in a very small size (~2x2 cm). Obviously  \includegraphics[width=2cm]{...}   actually lets me include them as expected but the resulting PDF file is too "heavy" (some GBs).  I know I could use an external image editor to decrease the file size but, for a couple of reasons too long to explain here, I'd prefer to set the image resolution (so that a lower resolution implies a lower PDF file size) from within LaTeX.  Is there a reasonably simple way to achieve it?  I'm using pdfLaTeX and the document I'm working on has no other peculiarities:  \documentclass{article} \usepackage{graphicx}  \begin{document} \includegraphics[width = 2cm]{example.jpg} % ... \end{document}

I am using  $ pdflatex --version pdfTeX 3.14159265-2.6-1.40.18 (TeX Live 2017/Debian) kpathsea version 6.2.3   to compile a 30-page pdf output. Twelve of the pages look like this (the rest are only text):    All items are generated by this code:  \newcommand{\weapon}[8] { \begin{multicols}{2}   \noindent \textbf{#2} \\   Необходима сила: #3  \\   Обсег: #4  \\   Щети: #5  \\   Свойства: #6  \\   Маса: #7  \\   Стойност: #8  \\   \includegraphics[height=0.13\textheight]{../images/#1}~ \end{multicols} \vspace{0.01cm} }   This bring the file size to:  remote: warning: File build/elementaris-fantasy.pdf is 63.06 MB; this is larger than GitHub's recommended maximum file size of 50.00 MB   The images I am using are not scaled and some of them are quire large.  How can I reduce the size of the PDF file? The purpose of the PDF is to be printed on sheets of paper as reference for a game.


In order to get Harry out of the Dursleys' house, the aurors decided to come up with a plan to use polyjuice potion to create seven Harry Potters, providing confusion over who the Death Eaters should go after. This was to avoid the problem of apparating out of the house, since Harry still had the Trace and the Ministry would know where he went. (Floo powder and portkeys also had some Ministry oversight, so were off the table).  Why didn't Harry just leave while wearing the Invisibility Cloak, perhaps going out at the same time that the Dursleys were moving out? That doesn't involve casting any spells and nobody can see Harry. So long as he's smart enough to get out without having any strangely opening doors, I think he'd be safe. Heck, since the Cloak is large enough to cover three children, perhaps he could even ride his broomstick while wearing it. Sure, there's the homenum revelio spell, but I can't imagine the Death Eaters casting it continuously for days on end.  Why didn't Harry leave the Dursleys' house under the Invisibility Cloak instead of having the Seven Potters plan?

In Harry Potter and the Deathly Hallows, a bunch of the Order of the Phoenix members show up to escort Harry to the Burrow.  The rationale behind this was that they couldn't use the Floo Network, they couldn't Apparate, they couldn't use a Portkey, and Harry still had the Trace on him.  Thus, they were all going to fly away, and have six decoys plus the real Harry Potter.  What I don't get is this:  Why didn't Harry just put on his Invisibility Cloak and walk out of range of the charm, and then Apparate away?  He's largely undetectable under the cloak, and as long as he were to get out of range of the Floo/Apparition restrictions, he could've met up with a couple of Disillusioned or invisible Order members and been on his merry way.  Why didn't he?


Is there a rule as to when I use "more" in a sentence or "-er"? For example, "I think it would be more fun/funner if we stayed home tonight." I know the correct usage in this sentence but is there a general rule to follow?

Which one of these adjectives is correct? I can see that both of them are being used, I'm just not sure which one is grammatically correct. Are there any general rules to follow as to the use of one against the use of the other?


I've recently bought a nikon 50mm prime 1/1.8f lens, and I'm learning about shooting portrait photos.  What I wonder about is how to focus on the eyes while having aperture wide opened at 1/1.8? The technique I know is to focus and recompose, but at such a wide opening the focus gets lost immediately in the process. My Nikon D3300 has only 16 AF points, which means that I should always focus on one of those points without any possibility to change the frame?  Also, which aperture should I choose? As far as I know, I should choose 1.8 for the best bokeh, step down a bit for better sharpness and tolerable bokeh...and try to choose "normal"/smaller apertures while shooting landscapes. How do I know which aperture is needed in which situation?

I've bought a  to use with my EOS 200D and while I love the wide aperture, it appears to be quite difficult to achieve sharp focus on people's faces when shooting at f/1.8. I've tried both using Dual Pixel focus in Live View and using the center focusing point in the viewfinder, but it doesn't get me perfect results.  Is this simply a characteristic of cheap wide-aperture lenses? Or is it impossible to get sharp focus with a fully open aperture?  When I'm at at home using a tripod and focusing on a still subject I do get good focus (so it's not a camera or lens issue). But it's hard to do with people who are slightly moving between shots.


$f$ is continuous function when $x \in [a,b]$ show that $M(x)=\sup\{ f(y):y \in [a,x]\}$ is continuous in $[a,b]$ Can someone help me to prove this ?  It seems simple but I can`t get started. I was far from real analysis for years, I Did not find a clue

I'm working on this problem from Elementary Analysis by Ross which is intuitive when sketched but keeps stymieing me when I try to write it out.  Let $f$ be a continuous function on $[a,b] \subset \mathbb{R}$. Define $f^\star (x)$ as:  $$ f^\star(x) = \sup \{f(y)\mid a \leq y \leq x \} $$ Prove that $f^\star$ is a continuous increasing function on $[a,b]$.  Things I've figured out: (these are mostly trivial)   $f$ is uniformly continuous on $[a,b]$. Since $[a,b]$ is closed and bounded there exists some $c \in [a,b]$ such that $f(c) \geq f(x)\ \forall x \in [a,b]$. (In words: the supremum is actually attained.) If $c \in [a,b]$ is as above, then $f^\star$ is constant (and hence continuous) on $[c,b]$ (which is possibly a singleton).   This seems completely obvious when you actually draw a continuous function but translating that to a formal proof eludes me...


\documentclass[letterpaper,10pt]{article} \usepackage{amsmath} \usepackage{nccmath}  \begin{document}  \begin{align*} \intertext{what is the vertical spacing here?} \\[-30pt] 1+2 \\ =3 \end{align*} \end{document}   There is an automatic vertical gap that the \intertext command inserts. I would like to know how many pts that gap is to exactly get rid of it with the \\[...] command explicit since manually adjusting this height gives me the freedom I require. -30pts is close, but it appears no integer value works and the ams manual doesn't specify the exact spacing of the intertext command.

I have a document I am trying to copy to learn TeX. Here is what I have encountered: How can I have the "or" in the equation. This is what I have right now:  \[ f = ma; \]  But $a$ is the change in velocity,  \[ f = m \frac{dv}{dt};\] \[ f = m  \frac{d^2y}{dt^2};\]   Edit: Trying out Stefan's answer


What is difference between select count(1) from table ; and select count(*) from table ;  Here my table contain 5rows and 5column

I seem to remember that (on Oracle) there is a difference between uttering select count(*) from any_table and select count(any_non_null_column) from any_table.  What are the differences between these two statements, if any?


Consider a heat equation  $\frac{\partial u(t,x)}{\partial t} = a^2 \frac{\partial^2u(t,x)}{\partial^2x},$ for $x \in (-\infty,+\infty), t\in(0,+\infty)$, $u(0,x)=0$ for $x \in (-\infty,+\infty)$ I know that there exists a unique solution in class of bounded functions. This solution in general case can be found by using Fourier transform. But there also exists unbounded solution. So, my question is how can I find it?

For the heat equation $(\partial_t-\partial_x^2)f(t,x)=0$ defined on $[0,T)\times(-\infty,\infty)$, to obtain uniqueness of the initial value problem, usually it is required to limit the growth of the potential solution at infinity, i.e. $|f(t,x)|<\exp(c\cdot x^2)$.  My question is, if we do not impose any such conditions, is uniqueness no longer valid? In particular, is there a well known example of a function $f(t,x)$ that satisfies the heat equation on $[0,T)\times(-\infty,\infty)$, $f(0,x)=0$, but $f$ is not identically zero?   What if we relaxed the conditions a little bit, and only required that $f$ satisfies the heat equation in $(0,T)\times(-\infty,\infty)$ and is continuous on $[0,T)\times(-\infty,\infty)$, is there an example in this case?


Consider a system of 10 (say) point particles each at a fixed distance from each other in 3-D space. In this case, the number of degrees of freedom: $3*(number-of-particle)-\binom{10}{2}=3*10-45<0$ which is wrong as it cannot be negative. So, is the number of degrees of freedom 6 by considering it a rigid body? If yes, why does the above formula fail?

Suppose we consider a rigid body, which has $N$ particles. Then the number of degrees of freedom is $3N - (\mbox{# of constraints})$.  As the distance between any two points in a rigid body is fixed, we have $N\choose{2}$ constraints giving $$\mbox{d.o.f} = 3N - \frac{N(N-1)}{2}.$$ But as $N$ becomes large the second term being quadratic would dominate giving a negative number. How do we explain this negative degrees of freedom paradox?


How can I found out which packages cause problems with the class svjour3?  After many compilations I found out that the problem lies in of the packages I use. The code is below and does not produce a pdf.   EDIT 1: The file svjour3.cls was modified on 1/10/2008. I use MiKTeX 2.9.   EDIT 2: The error is  ! TeX capacity exceeded, sorry [input stack size=5000]. \cl@chapter ->\cl@chapter                            \@elt {theorem} l.2486 }{}           %  end of \@ifpackageloaded{amsmath} !  ==> Fatal error occurred, no output PDF file produced! Transcript written on probleem.log.   PDFLaTeX Compilation Report:   (Pages: 0) Errors: 2   Warnings: 2   Bad Boxes: 0    \documentclass[smallextended]{svjour3}  \usepackage{amssymb} \usepackage{amsmath} \usepackage{undertilde} \usepackage{amstext} \usepackage{amsthm} \usepackage{epsfig} \usepackage{graphics} \usepackage{color} \usepackage{booktabs} \usepackage{graphicx} \usepackage{caption} \usepackage{float} \usepackage{subfigure} \usepackage[sort&compress,round,comma,authoryear]{natbib}%bibtex \usepackage{mathtools} \usepackage{epstopdf} \usepackage[titletoc,title]{appendix}% for appendix met A \usepackage{cleveref} \usepackage{dcolumn}   \begin{document} Hello \end{document}

I am getting this error while trying to build my tex file. As soon as I include the cleveref package, I get this error and it shows cleveref.sty with the cursor at the bolded part of the file.  \def\make@df@tag@@@#1{%     \gdef\df@tag{\tagform@{#1}%       \toks@\@xp{\p@equation{#1}}%       \edef\@currentlabel{\the\toks@}%       \edef\cref@currentlabel{[equation][2147483647][]\the\toks@}}} **}{}%  end of \@ifpackageloaded{amsmath}** \@ifpackageloaded{IEEEtrantools}{%   \PackageInfo{cleveref}{`IEEEtrantools' support loaded}   \let\cref@orig@@IEEEeqnarray\@@IEEEeqnarray   \def\@@IEEEeqnarray[#1]#2{%     \refstepcounter{equation}%   What could be the reason for this error?  from the comments:  \begin{filecontents*}{example.eps} gsave newpath 20 20 moveto 20 220 lineto 220 220 lineto 220 20 lineto closepath 2 setlinewidth gsave .4 setgray fill grestore stroke grestore \end{filecontents*} \RequirePackage{fix-cm}  \documentclass[smallextended]{svjour3}  \smartqed \let\proof\relax \let\endproof\relax \usepackage{cleveref}  \begin{document}  \title{Title} \author{First Author} \date{Received: date / Accepted: date}  \maketitle  \begin{abstract} \end{abstract}  \maketitle  \section{Introduction}  \end{document}


Looking for title/author of a short story I read in a sci fi anthology I read in the 80s. Here is the plot line I remember of one based on the visual imagery I had when reading rather than the text so possibly there are some embellishments.  An astronaut crashes or lands on a forest/plant covered planet.  I recall it being dark and raining.  I think the astronaut was on his own or in a group who died on a journey. He was trying to find safety in the form of a bio-dome.  He locates one but its smashed up and the vegetation has taken over.  I cant recall whether he travels to another and finds the same thing.  There is a some kind of twist - possibly the vegetation has attacked?  It will be in a collection and could be older than 80s as I used to borrow them from libraries in the UK.  It might have been young adult, possibly even children's.

It's not All Summer in a Day.  This was a story about explorers on Venus, who are separated from their base (possibly they're lost, possibly they suffered equipment failure, possibly they're just traveling from base to base) and are slowly being driven insane because it never stops raining.  The story is old enough that Venus' clouds were still believed to indicate a wet climate.  I can't remember much more detail than that.  I have the impression that the narrator at one point either dreamed of or fantasized about walking into the destination base and being handed a very plush towel to dry off.  I can't remember the central plot points - only the (very wet) setting.  I would have read this in the late 1970's or early 1980's.  I thought it might be an H. Beam Piper short story but I've been through his catalog and don't see any likely suspects.