First the error which i am recievieng is undefined is not a function. I am generating a table on ajax call by button click. The problem is that the click event on cell is not performing.  my code is like   $(document).ready(function () {     $('#btnCall').click(function () {        $.ajax({....           success: function (data) {              //Here i am creating a table with id = myTable           }        });    });     //After ajax call completed i am using this     //but this is not happening    //i want to show alert when cell clicked of the table     $("#myTable tr td").click(function(event) {          alert(event.pageX);          alert(event.pageY);     }); });

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


note: A few people have marked this question as duplicate - But my question here is not answered in the other question. Though a fine distinction, what I was asking about here was not whether the signs of a factor matters in the absolute, but whether there was any significance to the relationship between factors (i.e. whether they were largely the same sign, or largely different signs).  So I am fairly familiar with factor analysis, and am aware of answers  and  that tangentially address my question. I believe I am right in my answer to the question I'm asking, but I wanted to make sure.   Essentially, I have, for each of several hundred participants, answers to two sets of almost identical questions. For examples' sake, let's say these are ratings of their current mood state on 10 items at the start (A) and the end (B) of a questionnaire survey. I expect that these mood rating items should load onto two main factors (positive and negative) and that these loadings should be consistent (i.e. both sets A and B should break down similarly into two factors).  When I run the factor analysis, I find pretty much what I expected, except that for rating set A, items 1:5 load positively on factor 1, and items 6:10 load positively on factor 2, while for rating set B, items 1:5 load positively on factor 1, while items 6:10 load negatively on factor 2. Within each factor, the direction of the loadings are consistent across all items. This analysis was performed using varimax rotation.  Now, my understanding is that the difference between the two results is meaningless. Only the relative loading within each factor matters, and the reversal in sign is simply due to the factor analysis randomly converging on a factor that points in the opposite direction, but is essentially the same (except conceptually reversed). But I have had a colleague try to interpret the difference between the two analyses as meaning something with regards to the difference between the two factors.   Is my understanding right, or is there actually something to the difference?  A visual representation that might be more helpful - this is essentially what my output looks like:

I performed principal component analysis (PCA) with R using two different functions (prcomp and princomp) and observed that the PCA scores differed in sign. How can it be?  Consider this:  set.seed(999) prcomp(data.frame(1:10,rnorm(10)))$x              PC1        PC2  [1,] -4.508620 -0.2567655  [2,] -3.373772 -1.1369417  [3,] -2.679669  1.0903445  [4,] -1.615837  0.7108631  [5,] -0.548879  0.3093389  [6,]  0.481756  0.1639112  [7,]  1.656178 -0.9952875  [8,]  2.560345 -0.2490548  [9,]  3.508442  0.1874520 [10,]  4.520055  0.1761397  set.seed(999) princomp(data.frame(1:10,rnorm(10)))$scores          Comp.1     Comp.2  [1,]  4.508620  0.2567655  [2,]  3.373772  1.1369417  [3,]  2.679669 -1.0903445  [4,]  1.615837 -0.7108631  [5,]  0.548879 -0.3093389  [6,] -0.481756 -0.1639112  [7,] -1.656178  0.9952875  [8,] -2.560345  0.2490548  [9,] -3.508442 -0.1874520 [10,] -4.520055 -0.1761397   Why do the signs (+/-) differ for the two analyses? If I was then using principal components PC1 and PC2 as predictors in a regression, i.e. lm(y ~ PC1 + PC2), this would completely change my understanding of the effect of the two variables on y depending on which method I used! How could I then say that PC1 has e.g. a positive effect on y and PC2 has e.g. a negative effect on y?    In addition: If the sign of PCA components is meaningless, is this true for factor analysis (FA) as well? Is it acceptable to flip (reverse) the sign of individual PCA/FA component scores (or of loadings, as a column of loading matrix)?


Find the smallest positive multiple $n$ of 1994 such that the produc of the divisors of $n$ is $n^{1994}$  Attempt Let $n\in \mathbb{N}$ and denote by $d(n)$ the number of divisors of $n$ and $p(n)$ the product of all the divisors of $n$ including $n$. Consider the factorization of $n$ given by $n=p_1^{\alpha_1} p_2^{\alpha_2}\cdots p_n^{\alpha_n}$ for $\alpha_i\in \mathbb{N}$. Is known the fact that $p(n)=n^{d(n)/2}=n^{1994}$ it is $d(n)=997 \cdot 2^2$ in addition $n=997 \cdot 2 \cdot k\, $  for some  $k\in \mathbb{N}$. since $n$ is the smallest multiple of $1994$ with $997 \cdot 2^2$ divisors then $n$ should be $2^{998} \cdot 997$ Any comment or corretion was helpful

The function $d(n)$ gives the number of positive divisors of $n$, including n itself. So for example, $d(25) = 3$, because $25$ has three divisors: $1$, $5$, and $25$.  So how do I prove that the product of all of the positive divisors of $n$ (including $n$ itself) is $n^{\frac{d(n)}{2}}$.  For example, the divisors of $12$ are $1$, $2$, $3$, $4$, $6$, and $12$. $d(12)$ is $6$, and $1 · 2 · 3 · 4 · 6 · 12 = 1728 = 12^3 = 12^{\frac{6}{2}} = 12^{\frac{d(n)}{2}}$


Is there any way to calculate the % difference between two strings in Excel? For example, oftentimes a customer sends us a list of items that they want us to match with items in our system based on description and item SKU #. However, matching by SKU does not always return an accurate result, especially if it is short and not unique. If there was a more efficient way of doing this than manually searching & matching, it would greatly increase the efficiency of my job.  Optimally, the function would return a number... higher the number, better the possibility of a match. To be clear, both comparison cells are defined, and both exist in the same row. This would not be a  (already have that add-in).  Possible?

I am currently trying to reconcile “Name” fields from two separate data sources.  I have a number of names that are not an exact match but are close enough to be considered matched (examples below).   Do you have any ideas of how I can improve the number of automated matches?    I am already eliminating middle initials from the match criteria.    Current Match Formula:  =IFERROR(IF(LEFT(SYSTEM A,IF(ISERROR(SEARCH(" ",SYSTEM A)),LEN(SYSTEM A),SEARCH(" ",SYSTEM A)-1))=LEFT(SYSTEM B,IF(ISERROR(SEARCH(" ",SYSTEM B)),LEN(SYSTEM B),SEARCH(" ",SYSTEM B)-1)),"",IF(LEFT(SYSTEM A,FIND(",",SYSTEM A))=LEFT(SYSTEM B,FIND(",",SYSTEM B)),"Last Name Match","RESEARCH")),"RESEARCH")


Let's say I have  on my side of the field, and my friend plays . Would Progenitus still be on the field after Worldfire resolves or is he also exiled since he has "Protection from everything?"

Example 1) Let's say I have some random creature with protection from white, and my opponent plays , a white card with the effect "Destroy all creatures." Can my creature with protection from white be destroyed by a white card that isn't actually targeting it specifically?  Example 2) I was playing a match with a friend where I had  on the field against his 3 zombies. Is he able to declare his zombies as blockers even though Elite Inquisitor has "protection" from zombies?  If he can declare them as blockers, does protection mean that no damage is dealt by the zombies to  Elite Inquisitor?


I had previous problems like this, first it did not want to update anything. It always sad:  Failed to download repository information check your internet connection,  but i have internet connection and i discovered just to uncheck the PPA packadges that caused the problem and i successfully update all my software. After that a exclamation mark in triangular sign appeard next to Wifi icon that says:  The update information is outdated. This may be caused by network problems or by a repository that is no longer available. Please update manually by selecting 'Show updates' from the indicator menu, and watching for any failing repositories.  After clicking on that it says your software is up to date, but when i try to press update it's checking for cache and says, as always, FAILED TO DOWNLOAD REPOSITORY INFORMATION CHECK YOUR INTERNET CONNECTION.  Is this problem with a wirelles driver, or some packadges that needs to be removed? Solutions? Suggestions?

When I run software updater it says that it failed to download repository information and to check Internet connectivity.  I have Internet connectivity.  How do I fix this?  editing to add content of sources,list:  sorry I can't figure out how to paste in the content of sources.list without making a huge mess.  Some of it previews as really large bold print.  I tried to follow the block quoting and code rules but it is a huge mess anyway.


If I can't go back I'm getting rid of iPhone for droid, any help would be appreciated. My iPhone and all upgrades are legal, just hate new upgrade... Please help me Terry

I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this?


I need to swap bytes of a 32 bit value 11223344 should be swapped as 44332211. Currently i'm using following logic.  val = ((((val) & 0xff000000) >> 24)|       (((val) & 0x00ff0000) >>  8) |       (((val) & 0x0000ff00) <<  8) |       (((val) & 0x000000ff) << 24));   This is working as expected. But i just wanted to know is there any other fastest/Optimized way to do the same.

How do I convert between big-endian and little-endian values in C++? For clarity, I have to translate binary data (double-precision floating point values and 32-bit and 64-bit integers) from one CPU architecture to another.  This doesn't involve networking, so ntoh() and similar functions won't work here.  Note: The answer I accepted applies directly to compilers I'm targeting (which is why I chose it).  However, there are other very good, more portable answers here.


I'm trying to start an external application through system() - for example, system("ls"). I would like to capture its output as it happens so I can send it to another function for further processing. What's the best way to do that in C/C++?

I am looking for a way to get the output of a command when it is run from within a C++ program.  I have looked at using the system() function, but that will just execute a command. Here's an example of what I'm looking for:  std::string result = system("./some_command");   I need to run an arbitrary command and get its output. I've looked at , but I have not found anything that will give me what I need.


According to  and  answer, it becomes exceedingly difficult/impossible for a question to hit the HNQ once it gets older. When this  appeared on Science Fiction & Fantasy SE, it was over four years after the question had originally been asked. In spite of the epicness of the answer and overwhelming response (possibly the best ever on that SE), it should have been totally impossible for the question/answer to hit the HNQ, since the HNQ formula  However, SF&F SE moderator Rand al'Thor  due to the epic answer. Rand notes  by   I thought of the story as soon as I saw the post in hot network questions. Now I am lamenting not having seen it in the unanswered section.  The user has   Here's the data I can provide: When I saw the question in HNQ, I was on Win7 and using Internet Explorer 11 (only browser allowed on work computer at the time). I saw the question in the HNQ section on the right-hand side. At the moment, that section looks  for me. It's right underneath the Linked and Related questions lists. I was probably on either Puzzling or SuperUser since those are the two I frequent the most. I was definitely not on the root  site.  So:  Was this question really in the HNQ after the answer was posted? If yes, was it manually added* to celebrate the epic answer? If yes to #1 but no to #2, how was it possible?  I have tried to , but the records seem incomplete for the relevant time period. The problem seems to be that the the second, third, fourth page etc. of the front page aren't cached frequently enough to give detailed results. I've also gotten  saying "No questions found", further complicating research. * = I have never heard of a question being manually added to the HNQ, but if this question was actually there after the answer, I can't really think of any other explanation. Unless I have misunderstood the math somehow.

I really like the , where certain questions from the Stack Exchange Network are presented, along with a hotness rating that is described as "arbitrary" in its tooltip. Such questions also appear randomly on the sidebar on sites across the network, under the heading "Hot Network Questions". How do these arbitrary hotness points work, and how are they used to select questions to appear in those lists?


I have had questions on other boards edited with the reason "remove run on sentence"  but why are they bad I went to one page and the example was     I have a dog his name is George.   The suggested solution was     I have a dog. His name is George.   well I was taught that was wrong as you can't use his in a sentence alone, as a sentence is a standalone construct and we have no idea who "his" is (I have been roundly told my teacher was wrong).  another solution was      I have a dog, and his name is George.   This appears to be a rule without reason, so please what is the reason?    I have read the suggested  ,which has been closed, it is about comma-splice with only a passing nod to run on sentences.

Is this sentence acceptable?     You’re welcome, have a nice day ahead.


Can I display the checkboxes horizontally using lightning-checkbox-group tag? <lightning-checkbox-group                             onchange={handleChange}                             name={objectInfo.data.fields.Reason__c.apiName}                             label={objectInfo.data.fields.Reason__c.label}                             options={reasonOptions}                             value={recordInput.fields.Reason__c}></lightning-checkbox-group>

currently, I'm passing in a options array to the options attribute of a lightning-checkbox-group. I need to mimic the behavior of that tag, but I need to do it in html because I don't think I can get the checkboxes to display horizontally. I've tried <template for:each and have not had any luck. My goal would be to pass in the same name/value pair array, loop through it and call the same change handler that is called when using lightning-checkbox-group. A simple code snippet would be awesome. This is what I've tried so far: {lineItemObjectInfo.data.fields.Reason__c.label}  <template for:each={reasonOptions} for:item="option" for:index="index">
          <lightning-input onchange={handleChange}                            name={lineItemObjectInfo.data.fields.Reason__c.apiName}                            type="checkbox" label={option.label}                            value={recordInput.fields.Reason__c}></lightning-input>
  </template>  That actually gets me pretty close. When changed it fires the change handler and fails when I'm trying to do a .join on the recordInput for the field: handleChange(event) {     const {target: {name, value}} = event;        switch (name ) {         case "Reason__c":             this.recordInput.fields[name] = value.join(";");             break;         default:             this.recordInput.fields[name] = value;             break;     } }  I've also tried using a form tag with input and label tags but that didn't get me much further. The switch has been reduced for purpose of making it more clear. This is my original use of lightning-checkbox-group which functionally worked but styling is inflexible:
     <lightning-checkbox-group     onchange={handleChange}     name={lineItemObjectInfo.data.fields.Reason__c.apiName}     label={lineItemObjectInfo.data.fields.Reason__c.label}     options={reasonOptions}     value={recordInput.fields.Reason__c}></lightning-checkbox-group>


StackExchange / Stack Overflow were built on the premise that serving the developer community at large would lead to a better, smarter Internet but in my opinion the path that you have chose to reach that goal is a terribly slow one.  The Stack communities are full of great knowledgeable answers. To make the Internet better and smarter it’s going to take more than just answers. It’s going to take understanding and comprehension of those answers. The Internet is full of young and old minds yearning to comprehend. Isn’t discussion part of learning? How do people discuss some of the answers they find on the Stack sites? Isn’t discussion contributing?  My feature request is to expand your website to a sister website called discussion.stackexchange.com, a place to discuss posts found on Stack sites in a more relaxed manner.  By adding “Discuss this post on discussion.stackexchange” to the end of every thread like this mock up image:    You have the site where you talk about unicorns, and the meta site where you talk about the site where you talk about unicorns. What is needed is a place where the common user can talk about the knowledge represented on unicorns.   Currently, there are two main option to "discuss" a post: the chat and comments.  The chat, while more open to discussion, requires 20 reputation points to take part in. Adding comments on the question itself, if it's not your question, would instead take 50 reputation points, and that is not even considering that comments aren't meant for extended discussion in the first place. The spur-of-the-moment users will never reach that because they don’t strive to gain a reputation on the site. The site is just there for them as a means to comprehension, nothing more.  What is my definition of the spur-of-the-moment user? The spur-of-the-moment user is a general person just that is here to find comprehension to a question, someone that is busy doing their own project but needed understanding on some topic. They are not here to gain reputation and probably won't interact a lot with votes or by posting new content. How can someone gain reputation on a subject they are just learning? Especially if they are in competition with other more qualified users.  This community is the place  for the discussion of this knowledge, since this is where the knowledge is located, not Quora or reddit.  You don't have to participate in it if you don't want to. Lots of people will participate because they want others to learn.  There is entire market of people that will participate. The experts don't have to moderate the forum. Forums themselves attract the type of people that love to moderate them. The experts aren't required to participate but they will.   As a side notice, I would like to point out that  comments are still one of the most abused feature here, often being used as a way to discuss over a post in a more "forum like" way.     Honestly, comments are the single most abused feature of Stack   Exchange. However, they are also a very important part of stack   exchange.      I think that people are heavily abusing your comment feature to try to have a voice. They will continue to abuse it if you ignore them, but give them an outlet to speak and you will resolve one of your huge problems. The abuse will drop drastically and you can continue doing the others things you love, with much less hindrance.   For those that feel this request is unclear I'll break it down for you.  "My feature request is" that statement means that following it will be some words that state my request  "to expand your website to a sister website called discussion.stackexchange.com" means start a new web site that is called discussion.stackexchange.com  "a place to discuss posts found on Stack sites in a more relaxed manner" This web site will be a place where posts can be discussed in an atmosphere not as militarized as this site.  "By adding “Discuss this post on discussion.stackexchange” to the end of every thread" I think this sentence is very self-explanatory if you look at the mockup picture.

I've been seeing a lot of comments, on a lot of questions and answers, and most of them, seem to be related, some are asking new questions themselves, some are talking to the poster, looking for more information, but most of them seem to be more of discussion rather than comment.   But all these comments, are scattered, some are on the question itself, some are throughout all the different answers.  Would we benefit from having a separate Talk/Discussion page/tab/section that we could flesh out the details of the question, and ask more on, in one unified spot?  Also, it might be nice for questions that go unanswered, or the poster accepts a half-baked answer; so that people had a way of asking something like "hey did you ever figure this out" kind of deal and the poster still getting notifications on both sides.  I know it'd probably be difficult to get right, but maybe others have similar ideas on how to refine it, or something they'd like to see, or how to implement it?


I accidentally deleted the 2 admin account on my windows 10 then I restart my pc. After restart I'm not able to log in to my PC there's no account to be choose. What should I do?

I accidentally disabled my admin account.  After I login to another account I found I can not get admin rights, because all admin accounts on my computer are disabled.  I clicked on 'run as administrator' but only see a smart card choice (all the admin accounts are disabled so no choice provided)    I don't want to re-install my OS, help!    Details:  I have account A on my computer.    I got a new computer so I want to give the old one to my mother.    Creating a new user account B for her and disable account A.    Logout and restart.    Successfully login B, now I found I could not get admin rights because no account choice is provided.    More informations about my machine:  OS is Windows 10 and my admin account is a Microsoft Account.  I have an arch-linux installed on my computer and dual-boot it using GRUB, so maybe I can not use safe mode.


I'm running 18.04, and I'm attempting to install Wine, which has an unsigned repository. I tried bypassing this by using the --allow-unauthenticated flag, but I get an error  $ sudo apt-add-repository https:/dl.winehq.org/wine-builds/ubuntu/ --allow-unauthenticated Usage: apt-add-repository <sourceline>  apt-add-repository is a script for adding apt sources.list entries. It can be used to add any repository and also provides a shorthand syntax for adding a Launchpad PPA (Personal Package Archive) repository.  <sourceline> - The apt repository source line to add. This is one of:   a complete apt line in quotes,   a repo url and areas in quotes (areas defaults to 'main')   a PPA shortcut.   a distro component    Examples:     apt-add-repository 'deb http://myserver/path/to/repo stable myrepo'     apt-add-repository 'http://myserver/path/to/repo myrepo'     apt-add-repository 'https://packages.medibuntu.org free non-free'     apt-add-repository http://extras.ubuntu.com/ubuntu     apt-add-repository ppa:user/repository     apt-add-repository ppa:user/distro/repository     apt-add-repository multiverse  If --remove is given the tool will remove the given sourceline from your sources.list  apt-add-repository: error: no such option: --allow-unauthenticated   I've seen other users on the site with the same version of Ubuntu claim this option works. What am I doing wrong here?

I am looking for a step by step instruction to guide me in the ways of installing, configuring and debugging many of the issues new users have when dealing with Wine in Ubuntu.  What is the recommended way of installing Wine, some of the key issues that it has and how to solve them?  If I have a specific problem with an App in Wine, how do I go about solving it? What are the recommended steps to ensure that I can fix a problem related to an app I wish to use?


How do you access the site meta from the iOS app? I didn't see it in the menu, or in the list of sites in the menu bar. Is this not implemented yet?

I'd like to be able to easily browse the per-site metas of some sites. Unfortunately, there isn't an easy way to do this from the iOS app.  I tried searching for 'meta' in the other site chooser gizmo, but only mSO showed up. I've also tried tapping random likely-looking images and text. No luck.  Eventually, I found that I can do this by scrolling through my inbox and finding a notification from the meta I want to visit. I tap on it, then hit the back button. I can then see the meta's question list.   Can we please make this easier?


I have this code where i have two fixed navbars at the top and bottom.  I want the box to be of the size between the two navbars and to change it with the size of the nav changing with the size of the screen to always see the margin and the text of the cards.    body, html{   width:100%;   height:100%;   margin:0; }    .nav{   padding:5px;   margin:0;   position:fixed;   width:100%;   background-color:#84a9ca;   font-size:5vh; } .bas{   opacity:0.5;   bottom:0; } .box{   width:100%;   height:100%;   background-color:#6ec6e1;   display:flex;   justify-content:space-around;    } .element{   background-color:#488a45;   width:100px;   margin:5px; }
nav

element

element

element

nav

I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ }

...

...

     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works.


Mountain Lion and later OS X releases have a very useful feature where Time Machine can alternate between multiple backup destinations. I use this to back up to both a network share at home and an external drive I keep offsite. Because I only have physical access to the offsite drive occasionally, I don't back up to it often.  After 10 days, OS X gives me a message around the same time each day, such as:     Time Machine is still backing up successfully to the network share every hour, so this message is unnecessary (and the second sentence is incorrect).  I like being able to see when the last backup was completed, so I'd prefer not to remove the disk from Time Machine's destination list entirely. Likewise, turning Time Machine off (as suggested ) isn't an option because I still need my backups to run on the other drives.  Is there any way to disable or delay this message? Ideally I would be able to set it to a longer period of time, so it could remind me to go do an offsite backup every month or so.

(Updated answer choice for High Sierra. See the old answer if you are still on Yosemite)  I'm running OS X Yosemite, and I want to disable the notifications from Time Machine. I rarely do a hard-drive backup because all of my essential files are in the cloud. I don't need to run timemachine as often as it suggests/warns/annoys me about.  How do I disable the notifications? Time Machine is not in the Notifications preferences, and I don't want to stop using it entirely.


I have gone through this web application which can save and edit local files using web application.  I didn't get how they do it? Anybody has idea for this ?

Is there local file manipulation that's been done with JavaScript? I'm looking for a solution that can be accomplished with no install footprint like requiring .  Specifically, I'd like to read the contents from a file and write those contents to another file. At this point I'm not worried about gaining permissions and am just assuming I already have full permissions to these files.


Hello I have some small pitts of rust on my 1980 Raleigh royal frame. I don't want to strip the paint and sand blast it are there any non invasive treatments? Some of the chrome surfaces also appear to have been eaten away is there anyway to repair the chrome or is it a lost cause?

I have a small spot of rust on the bottom side of my steel frame's top tube (Columbus Niobium tubing).  It's from abrasion during transport that I didn't notice until it was too late.  The spot is about 2cm x 2cm and most the worn area is white in colour (base coat or primer?) but there's a bit of rust forming in the center.  I'm not ready to get the frame totally repainted so what's the best way to get this patched up?


How can one prove that  $$\ln\left( \frac{1+x}{x}\right) >\frac{1}{1+x} \, ?$$

I would like to prove the following inequality without integration; could you help?   $$\frac {1}{x+1}\leq \ln (1+x)- \ln (x) \leq \frac {1}{x}, \quad x > 0. $$  I can however differentiate this.  Thanks in advance.


Let $f(x)$ be a polynomial of degree n with real coefficient and such that $f(x)\geq0$ for every real number $x$ prove that $ f(x)+f'(x)+\dots+f^{(n)}(x)\geq0 $ for all real number $x$. I thought about the following. Since $f(x)$ is positive for all real number, then $f(x)$ must be even function, with a positive leading coefficient. Any hints will be appreciated

Let $p(x)$ be a polynomial of degree $n$ satisfying $p(x)\geq 0$ for all $x$. That is, for all $x$, $p(x) = a_n x^n + a_{n-1} x^{n-1} + \cdots + a_1 x + a_0 \geq 0$, $a_n\neq 0$.  Show that $p(x)+p'(x)+p''(x)+\cdots+p^{(n)}(x)\geq 0$ for all $x$ where $p^{(i)}(x)$ is the $i^\text{th}$  derivative.  My interest: I know that, we can rewrite the LDE as follows  $$ p(x)+p'(x)+p''(x)+\cdots+p^{(n)}(x) = Lp(x) $$  where $L := I + D + D^2  + \cdots + D^{(n)}$. Can we say anything about a linear operator of this kind so that it does not change the sign of the input it takes? I can try to solve the question by writing for all the derivatives and factoring them using $p(x)$, but I think there should be a clever way of showing this by the properties of $L$. Can I figure out a solution by just looking at $L$ and the sign of $p(x)$ as in the question? Where should I look for that?


Many are familiar with the hello world program in C:  #include <stdio.h>  main () {     printf ("hello world");     return 0; }   Why do some precede the main() function with int as in:  int main()   Also, I've seen the word void entered inside the () as in:  int main(void)   It seems like extra typing for nothing, but maybe it's a best practice that pays dividends in other situations?  Also, why precede main() with an int if you're returning a character string? If anything, one would expect:  char main(void)   I'm also foggy about why we return 0 at the end of the function.

What is the correct (most efficient) way to define the main() function in C and C++ — int main() or void main() — and why? And how about the arguments? If int main() then return 1 or return 0?  There are numerous duplicates of this question, including:       — For C++, with a very good answer indeed.     Related:


Is it possible to create an x-y Plot with addplot table where the x-axis entries are not shown, but instead text can be inserted for each one? This is because I have a file containing bonds and I'd like to write CH instead of 1 CN instad of 2,... The legend is already used to describe the different data sets. Of course I could write a separate "legend" in which I'd define 1=CH, 2=CN, but I have the feeling it should be possible to rename the axis entries. However I have not found anything of that sort so far.  Here is the code:  \begin{tikzpicture} \begin{axis} [xlabel = {Bond}, ylabel={Länge in \si{\angstrom}}, xmin= {0}, xmax={14}, legend style={legend pos=  outer north east}]  \addplot [blue, only marks, mark=x, legend entry= {6-31G(d,p)}] table [x expr=\thisrowno{0}, y expr=\thisrowno{2}, header=true] {plot/raw/length/13RHF.txt};   \addplot [green , only marks, mark=x, legend entry= {6-311G(d,p)}] table [x expr=\thisrowno{0}, y expr=\thisrowno{5}, header=true] {plot/raw/length/13RHF.txt};   \addplot [purple, only marks, mark=x, legend entry={cc-pVDZ}] table [x expr=\thisrowno{0}, y expr=\thisrowno{8}, header=true] {plot/raw/length/13RHF.txt};   \addplot [black, only marks, mark=x, legend entry={cc-pVTZ}] table [x expr=\thisrowno{0}, y expr=\thisrowno{11}, header=true] {plot/raw/length/13RHF.txt};   \addplot [pink, only marks, mark=x, legend entry={cc-pVDZ?}] table [x expr=\thisrowno{0}, y expr=\thisrowno{14}, header=true] {plot/raw/length/13RHF.txt};   \addplot [yellow, only marks, mark=x, legend entry={SVP}] table [x expr=\thisrowno{0}, y expr=\thisrowno{17}, header=true] {plot/raw/length/13RHF.txt};   \addplot [orange, only marks, mark=x, legend entry={TZV}] table [x expr=\thisrowno{0}, y expr=\thisrowno{20}, header=true] {plot/raw/length/13RHF.txt};   \addplot [red, only marks, legend entry={GAFF}] table [x expr=\thisrowno{0}, y expr=\thisrowno{2}, header=true] {plot/raw/length/13GAFF.txt}; \addplot [red, only marks, mark=o, legend entry= {XXX} ] table[x expr=\thisrowno{0}, y expr=\thisrowno{2}, header=true] {plot/raw/length/XXX.txt};   \end{axis} \end{tikzpicture}  the preamble uses apart from the regular tikz/pgfplots/pgfplotstable packages and the tikzexternal/pgfplotsexternal libraries:  \pgfplotsset{     legend entry/.initial=,     every axis plot post/.code={%         \pgfkeysgetvalue{/pgfplots/legend entry}\tempValue         \ifx\tempValue\empty         \pgfkeysalso{/pgfplots/forget plot}%         \else         \expandafter\addlegendentry\expandafter{\tempValue}%         \fi     }, }

I'm very new to the TikZ environment. I'm trying to replace the "4" in the following graph by a Greek letter (ideally a \tau^{*}). Any idea ? Thanks in advance  \begin{document} \begin{tikzpicture}[     declare function={             gamma(\x)= 0.25*\x*\x*exp(-0.5*\x);     } ]  \begin{axis}[   no markers, domain=1:13, samples=200,   axis lines*=left, xlabel=$\tau$, ylabel=$V(\tau)$,   every axis y label/.style={at=(current axis.above origin),anchor=south},   every axis x label/.style={at=(current axis.right of origin),anchor=west},   xtick={4}, ytick=\empty,   enlargelimits=false, clip=false, axis on top,   grid = major,       xmin=0, ymin=0, ] \addplot [very thick,cyan] {gamma(x)};  \end{axis} \end{tikzpicture}  \end{document}


I accidentally used sudo rm * while I was in the root directory. Now, I am not able to open terminal and my computer does not shut down, only a single _ is flicking on the black screen. How can I solve this/reset my computer?

I stupidly ran sudo rm /* followed by sudo rm -R /*  My sites still run, although the vast majority of commands like ls are now broken.  Is there a simple way to get data off the server or reverse some of damage?


Can anyone suggest a nice eBook reader in Ubuntu?   Preferably something lightweight.

What software can I use to view .epub documents?


I will brief about the problem, that how it started.   I purchased a Sony VAIO (SVE15133CNW) laptop on May-2013, with pre-installed Windows 8 After couple of days I installed Ubuntu 13.04 using    USB in a dual boot mode; Both were working fine for few weeks One day, while the Ubuntu shutdown was still in progress, I closed the lid (I did this before as well many times); But this time it did some corruption While next starting up, it directly booted to Windows 8 and that happened repeatedly. The GRUB menu never really appeared. During trying to fix it, I hard shut down Windows 8 few times. I posted a  as well Then, I tried with "Boot repair" tool and finally the GRUB was back, I was able to login to Ubuntu without any problem Unfortunately, Windows 8 would never really boot after that; It will do some auto repair stuff and then give an error and then go back to the GRUB menu.   After searching numerous forums, there is no luck (from this forum too, I tried many suggestions which also include  and ). I tried every possible option, like editing the Windows 8 entry by pressing "E" and changing the current gpt3 into gpt1 till gpt8. But it always gives the :       can't find command 'drivemap'   invalid EFI file path   At the max after repairing, it reaches to the error which points out to .  For many days, I am in this situation. If someone can fix this, I would be really thankful. :) On other side, I don't have much data in Windows 8, but have lots in Ubuntu. As a final resolution, is there a way by which I can re-install Windows 8 without affecting Ubuntu partition?  I can still access Windows memory inside Ubuntu and here are some of the files which are appearing under "C:\Windows\System32\Logfiles\Srt":   .     Please let me know if something more is needed.  This is the latest result in pastebin of running . Here are some of the photos if they help:

I installed Windows on my computer, followed by an installation of Ubuntu. However, now I'm unable to boot into my Windows install.  What can I do to fix this?


I am new at Linux and I am facing a problem. I am trying to add the bin directory to the PATH in the Linux executing the command below:  $ export PATH="/opt/gcc-arm/bin:$PATH"   However, when I try to execute a command it returns me it was not found  Command 'arm-none-eabi-gcc' not found, but can be installed with: sudo apt install gcc-arm-none-eabi   How could I add this directory to Linux PATH or there is a way to access the User variables from Windows using the Linux?  Edit1: I just run $PATH and I got this:  bash: /opt/gcc-arm/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/mnt/c/Program:   The Path to the file that I created is there (/opt/gcc-arm/bin), but I do not understand why the system cannot recognize it.   Edit2: I executed the command suggested by @steeldriver      what is the result of file /opt/gcc-arm/bin/arm-none-eabi-gcc run   The result is: /opt/gcc-arm/bin/arm-none-eabi-gcc: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/l, for GNU/Linux 2.6.24, BuildID[sha1]=7af6e16f1d030393cdf4a6e6007a0e554470f126, stripped. But I have no idea what it means.  Edit3: Now the things start to work, first I use the command sudo -s and then   $ export PATH="/opt/gcc-arm/bin:$PATH".   After doing that I was able to run the commands from that PATH, however, when I close the Linux env and open again, it can not recognize those commands, so I have to include the PATH  again.  Is there some solution to avoid entering the PATH every time when I reopen the Linux?  Edit4: I followed this tutorial from Youtube , now my PATH is permanent.  I hope this can help someone else that face this same problem

How do I add a directory to the $PATH in Ubuntu and make the changes permanent?


I'm an Italian citizen. I came to the USA on a tourist visa 2 years ago but overstayed. I only have my Italian passport with me. Should I be fine flying within the US with no worries? Is anybody going to ask me for my immigration status? I'm very scared.

I am a foreigner and my student visa expired last month. I do have an American driver's license valid until the end of next year. Can I still fly inside the US without being afraid they will check my papers and try to get me out of the country? I haven't used any of my European IDs or passport in 2 years since I got the US ID, so I haven't been showing them off. I've been feeling pretty secure with my license. What do you think?


I've installed Magento2 on Ubuntu using ssh on AWS EC2. However I would like the niceties of a control panel such as cPanel/Plesk to make things easier.   I've read that cPanel is not supported, can Plesk be used and is it a good alternative for someone not too familiar with Linux commands?  Is there any other way of remoting into Linux which provides a UI ?  Thanks

As a dedicated Ubuntu server or as a VPS, I am looking for a web control panel, something like cPanel which is something like a web administrator for a server.  I have not used any on Linux since I do everything through the terminal, but still want to know what I can use in the case I have to recommend Ubuntu Server with such an application installed.


I know that $$1^3+2^3+3^3+\cdots+n^3=\left(\frac{n(n+1)}{2}\right)^2$$  What I would like to know is whether there is a simple proof (that obviously does not use the above info) as to why the sum of the first $n$ cubes always a perfect square.

I recently proved that  $$\sum_{k=1}^n k^3 = \left(\sum_{k=1}^n k \right)^2$$  using mathematical induction.  I'm interested if there's an intuitive explanation, or even a combinatorial interpretation of this property. I would also like to see any other proofs.


I am in Boulder, CO, but work on a machine in SoCal.  Careers is always suggesting jobs in LA.  Does careers use my stated location, or my IP address, or is this just a coincidence?

I'm in Bristol, England, and Careers appears to know that (my Profile page shows "Bristol, England"). Whenever I visit the homepage, though, Careers shows a section for "jobs near worcester".  Now, I'm sure Worcester has a lot going for it, but it's a relatively small city more than 50 miles away from where I am, so I'm just curious as to (a) why Careers is so keen to show me jobs near Worcester, and (b) if there's any way of telling the homepage to show me jobs near where I live, instead?  EDIT: I've since checked Careers from work (dangerous!) rather than home and it shows me jobs from London, which is even further away from me. So I guess it's ignoring what I've specified and guessing, wrongly, by IP address.


I want to reset Ubuntu. I have searched it on Google many times and I am new to Ubuntu so I am wondering how to reset it without too much complication. I have already tried re-installing it but my computer will not boot from the DVD. I am using Ubuntu 14.04.2 LTS.  I want to completely delete everything and have it start like it did when it was originally installed. Completely erase everything and restart, reinstall, and reconfigure Ubuntu.

I've had a lot of problems lately and now I'm having problems logging in at the login screen. I'm giving up and just want to reset and start over. How can I "factory reset" Ubuntu, in this situation, or, for future reference, in general?


Here is the feature in question:  Sunlight Sensitivity. You have disadvantage on attack rolls and on Wisdom (Perception) checks that rely on sight when you, the target of your attack, or whatever you are trying to perceive is in direct sunlight.  And the spell, Daylight:  A 60-foot-radius sphere of light spreads out from a point you choose within range. The sphere is bright light and sheds dim light for an additional 60 feet. If you chose a point on an object you are holding or one that isn't being worn or carried, the light shines from the object and moves with it. Completely covering the affected object with an opaque object, such as a bowl or a helm, blocks the light. If any of this spell's area overlaps with an area of darkness created by a spell of 3rd level or lower, the spell that created the darkness is dispelled.  Clearly it is not explicitly spelled out in the text, but still I'm not sure if the reader is meant to assume an intended effect, since "Daylight" and "Sunlight" are synonymous.

My PCs have a spear which is able to cast the Daylight Spell. Would this have any effect on Vampires in the spell radius like regular Sunlight would or would it just be considered Bright light for the vampire and have no ill effects against him?


but I need to create it with these configs GPT partition scheme for UEFI computer It is possible to do with rufus but it does not work in linux (I tried with wine) so somebody knows some program like rufus for linux sorry for my incredible english

This is the third time I've tried to install Ubuntu Server 14.04.03 64-bit on the same laptop, and each time it caused different problems.  Each time I wrote the same iso image to a USB flash drive by using a different application and OS.   Universal USB Installer (pendrivelinux.com) from Windows WinImage writer from Windows built-in image writer from Linux Mint 17.2    The iso image is the same in all three cases, the USB flash drive is the same, and the laptop is the same. However each time the installation of Ubuntu gave me different installation options. For example, the last time I installed Ubuntu, it didn't show all the packages to choose while installing (Basic Ubuntu server, etc.).


I’m trying to scrap prices from various e-commerce site. However the IMPOrtxml function is not working  For instance,

Google Sheets has several import functions   IMPORTDATA IMPORTFEED IMPORTHTML IMPORTXML   Sometimes the above functions returns errors like #N/A Imported content is empty and would like to be sure that there isn't a problem with the resource content to be imported.  How do I know if these functions are able to get the content that I looking to import?  I know that there also exist IMPORTRANGE but that function only is able to import content from Google Sheets spreadsheets


I'm trying to hide a process from task manager. Is it possible ? Btw. it isn't a malware program or something else.

I have a requirement to hide a process in Task Manager. It is for Intranet scenario. So, everything is legitimate. :)   Please feel free to share any code you have (preferably in C#) or any other techniques or any issues in going with this route.  Update1: Most of the users have admin privileges in order to run some legacy apps. So, one of the suggestion was to hide it in task manager. If there are other approaches to prevent users from killing the process, that would be great.  Update2: Removing the reference to rootkit. Somehow made this post look negative.


$A$ is a matrix sized $n\times n$, all elements in $A$ are $\pm1$. Find $\max |A|$.   My Attempt Denote $f(n)=\max |A_{n\times n}|$. $f(1)=1$. $f(2)=2$ is also obviously. If $n\ge2$, $|A|$ must be even. For $n=3$, $f(3)\ge4$ because $\left|\begin{array} r1&1&1\\1&-1&1\\1&-1&-1 \end{array}\right|=4$. Also, $|A|=A_{11} A_{22} A_{33}+A_{12} A_{23} A_{31}+A_{13} A_{21} A_{32}-A_{13} A_{22} A_{31}-A_{11} A_{23} A_{32}-A_{12} A_{21} A_{33}$ can not be $6$ since $A_{11} A_{22} A_{33}A_{12} A_{23} A_{31}A_{13} A_{21} A_{32}A_{13} A_{22} A_{31}A_{11} A_{23} A_{32}A_{12} A_{21} A_{33}$ must be $1$.  $1\ne 1\cdot1\cdot1\cdot(-1)\cdot(-1)\cdot(-1)$. Hence we have $f(3)\ne 6$. $f(3)=4$. For $n\ge4$, I have no idea where to start with $f(n)$. A trivial bound is $0<f(n)\le n!$. EDIT Related question: It is not duplicated since I am discussing $n\times n$ determinants, not $3\times3$.

Find Maximum value of Determinant of $3 \times 3$ Matrix  with  entries $\pm 1$  My try:  I considered a matrix as :  $$A=\begin{bmatrix} 1 &-1  &-1 \\  -1 &1  &-1 \\   -1&-1  &1  \end{bmatrix}$$  we have $$Det(A)=-4$$ and maximum is $4$, but how can we show that these are max and min values?   I also tried as follows:  By definition Determinant of a matrix is dot product of elements of any row with corresponding Cofactors  hence  $$Det(A)=a_{11}C_{11}+a_{12}C_{12}+a_{13}C_{13}$$  By cauchy Scwartz Inequality we have  $$a_{11}C_{11}+a_{12}C_{12}+a_{13}C_{13} \le \left(\sqrt{a_{11}^2+a_{12}^2+a_{13}^2}\right)\left(\sqrt{C_{11}^2+C_{12}^2+C_{13}^2}\right)$$  any way to proceed here?


I'm creating a dynamic page using clone property.   The problem occurs when I create say 4 Assured elements and when I close the first Assured (i.e) Assured 1, the close if statement occurs multiple times based on the nth-element value (hopefully).   I would like only one loop to occur such that the id-- occurs only once...    $(document).ready(function() {   var id = 1;   var assured = document.getElementById('assuredconb');    $('.add-contact').click(function(e) {     e.preventDefault();     if (id < 5) {       $(this).closest('li').before('
New assured ' + id + '
');       var clone = assured.cloneNode(true);       clone.id = "assured" + id;       $('.tab-content').append(clone);       id++;     }      $('.close').click(function() {       id--;       var anchor = $(this).siblings('a');       $(anchor.attr('href')).remove();       $(this).parent().remove();       $(".nav-tabs li").children('a').first().click();       alert(id);     });    });  }); .close {   color: red;   opacity: 0.8;   position: absolute;   right: 5%;   top: 25%; }  .nav-tabs>li>a {   width: 175px;   text-align: center; }  .add-contact {   width: 50px !important; } <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"> <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap-theme.min.css" rel="stylesheet">   <link href="https://use.fontawesome.com/releases/v5.0.2/css/all.css" rel="stylesheet">

Mr.X

Mr.Boy

#1

#2

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


Having read  I have not managed to find any solution to my problem, so decided to make a new post. At first, consider the following code: \documentclass[11pt,a4paper]{article} \usepackage[english,greek]{babel} \usepackage[iso-8859-7]{inputenc} \usepackage{amsmath,tikz} \title{\foreignlanguage{english}{On the explanation of my Problem}} \author{Μάρκος Βασίλης} \begin{document} \maketitle \section{\foreignlanguage{english}{Latin text}} \foreignlanguage{english}{Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text  Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text  Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text, 1} \section{Ελληνικό κείμενο} Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο  Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο  \section{\foreignlanguage{english}{Math}} \[\ln x\leq x-1,\ x>0\] \section{\foreignlanguage{english}{Tikz}} \begin{tikzpicture} \draw[thick] (0,0) circle (1cm); \draw[thick, draw=red] (0,0) circle (1.2cm); \end{tikzpicture} \end{document}  Now, when typeset, it gives the following result:  If we zoom a little bit on each paragraph we will see that, despite english, math and tikz content are diaplayed in the usual high resolution of LaTeX, greek text is as follows:  Also note that 2018, in the date section of the title appears in low-resolution but, when in latin, it is allright. So, how could I also have a greek text of equally high resolution? Note that I could typeset normally in the same resolution with my previous installation of MikTeX and, despite installing the same version (2.9), I got this problem, now (typeset with pdfLaTeX). So, any help would be pretty much appreciated! Thanks in beforehand!

I'm using a custom class file.  My main file looks like this:  \documentclass[12pt,a4paper]{thesis} \begin{document} \frontmatter     \pagenumbering{alph}      \pagenumbering{roman}     \clearpage      \cleardoublepage     \tableofcontents     \clearpage     \listoffigures     \clearpage     \listoftables   \mainmatter        \part{test}       \input{test} \end{document}   If I put this in my test.tex it does work:  \chapter{test} \label{chapter:test} test    When it becomes more text (lets say 40x the word "test") I get the error stated in my question title.  To test it I brought my class file down to this:  \ProvidesClass{thesis} \NeedsTeXFormat{LaTeX2e}  % Based on the memoir class \DeclareOption*{\PassOptionsToClass{\CurrentOption}{memoir}} \ProcessOptions \LoadClass{memoir}   I'm totally confused what is causing my error now.  This is the complete error:  ! pdfTeX error (font expansion): auto expansion is only possible with scalable  fonts. \AtBegShi@Output ...ipout \box \AtBeginShipoutBox                                                    \fi \fi


Assuming the negation of the continuum hypothesis, there is a set $G_1 \subset \mathbb{R}$ such that if $\aleph^\prime_1$ is the cardinality of $G_1$, then $\aleph_0 < \aleph^\prime_1 < \mathfrak c$.  Do there exist models of set theory in which there exist another set, say $G_2$ such that $\aleph_0 < \aleph^\prime_1 < \aleph^\prime _2 < \mathfrak c$ with $\aleph^\prime _2$ the cardinality of $G_2$ and so on (that is, the cardinality of $G_2$ is bigger than that of $G_1$ and less than the cardinal of the set if real numbers)? Is it possible to repeat this process and find sets with larger and larger cardinalities which still are less than $\mathfrak c$? If the answer is yes, what are the consequences of this assumption in analysis?

What can be said in general (if we do not assume the continuum hypothesis) about the cardinality of the set of all infinite cardinals smaller than $\aleph$?


I have a base class, Card, and a derived class,  SkillCard, declared as such: class SkillCard : public Card { private:     int skillType;     int numberValue; public:     SkillCard();     SkillCard(int x, string z, int y, int w); };  While Card is declared: class Card { public:     string name;     int manaCost;     Card();     string printCard();     Card(string x, int y); };  I store cards of different types in the deck (eventually there will be AttackCard, PowerCard etc) so cards are stored in the deck as: SkillCard increaseCard(0, "Increase Strength", 0.05, 5); userDeck.addCard(increaseCard, 1);  userDeck is an object of the deck class, which is declared as: class Deck { private:     int size;     Card* deck = new Card[1]; public:     Deck();     Deck(int x);     void addCard(Card toAdd, int place);     Card getCard(int place);     void setSize(int x);     int getSize();     void changeDeck();     void deleteDeck(); };  However, a problem arises when I try to return a card from the deck, done as SkillCard returned = userDeck.getCard(1);, since that returns a Card type. Can I convert this returned Card type to SkillCard?

Someone mentioned it in the IRC as the slicing problem.


How do I create this text style with multiple offset fill colours in Illustrator please?

I want to be able to create a anti-aliasing effect as shown in windows command prompt with any text or vector I'd like without having to screenshot it within the program. How could I go about doing this?


Let ∼ be an equivalence relation on a topological space X such that each equivalence class is connected and the quotient space X/ ∼ is connected. Show that X is connected.  My  thinking that:  let $p\colon X \to Y$ be a quotient map  as  that if each set $p^{-1}({y})$ is connected, and if $Y$ is connected, then $X$ is connected.   I don't know the proper proof   Pliz help me

Let $p\colon X \to Y$ be a quotient map. Show that if each set $p^{-1}({y})$ is connected, and if $Y$ is connected, then $X$ is connected.     I am totally stuck on this problem. Can I get some help how to tackle this problem


Problem: Find a closed, uncountable without rationals,  subset in the unit interval.   Solution: Let X be any binary irrational number , replace the 1s with 2s in the decimal expansion .   Now we can use the digits of X as an index for a path through the cantor set, for example, if the first two digits of X are 0 2 then we take [0 , 1/3] and then we take [2/9 , 1/3] .   This subset is obviously closed and uncountable, and since we are using an irrational index all the elements of that subset will be irrational.   Ok, is there a big mistake here? And secondly, If all the end points of a cantor set are rational doesn't this contradict the above?

Give an example of a perfect set in $\mathbb R^n$ that does not contain any of the rationals.  (Or prove that it does not exist).


PKG will be sending the Private key,so it may not be secure,some one may get the private key,how to overcome this problem in IBE. Please help am unable to justify.

I'm using IBE in my applied-crypto project in primitive form. I saw many articles about IBE, but didn't find how user can get private key is generated by PKG after EXTRACT method.  So, my question: What is the best practice to hand private key to user after EXTRACT method?


See edit below, thanks  I have the following test script (important note: I cannot change this part):  while (($#)); do   echo $1   shift done   Running the command ./test aaa "bbbb cccc" ddd gives the following output:  aaa bbbb cccc ddd   which is what any sane person would expect.  I have another script:  mode="good" status="okay" name="bro" description="very good man dood" extra=""  # ----  PARAMS=""  // $1: key, $2: value function addParam {     if [ ! -z "$2" ]; then         PARAMS="$PARAMS --$1 \"$2\""     fi }  addParam "mode" "$mode" addParam "status" "$status" addParam "name" "$name" addParam "description" "$description" addParam "extra" "$extra"  echo ./test $PARAMS ./test $PARAMS   The output from echo is ./test --mode "good" --status "okay" --name "bro" --description "very good man dood", so I would expect the output of ./test $PARAMS to be  --mode good --status okay --name bro --description very good man dood   but instead, for some reason, I get the following output:  --mode "good" --status "okay" --name "bro" --description "very good man dood"   If I copy the output of echo ./test $PARAMS and paste it, I get the expected output from ./test. So I tried removing the last line which executes ./test and leave the echo line last, but apparently $(./script) still does not work and I'm beyond ideas.  What am I doing wrong?    Edit: @steeldriver's solution works but there's another constaint - I have to allow users to send their own arguments.  So having this script (thanks @steeldriver):  #!/bin/bash  mode="good" status="okay" name="bro" description="very good man dood" extra="" arguments="--config \"blablabla=yes\" --config2 \"bla2=no problem\""  # ----  declare -a PARAMS  # $1: key, $2: value function addParam {     if [ ! -z "$2" ]; then         PARAMS+=("--$1" "$2")     fi }  addParam "mode" "$mode" addParam "status" "$status" addParam "name" "$name" addParam "description" "$description" addParam "extra" "$extra"  # (1) PARAMS+=("$arguments")  # (2) PARAMS+=($arguments)  echo ./test "${PARAMS[@]}"  ./test "${PARAMS[@]}"   The desired output is:  --mode good --status okay --name bro --description very good man dood --config blablabla=yes --config2 bla2=no problem   However the output I get is:  With (1):  --mode good --status okay --name bro --description very good man dood --config "blablabla=yes" --config2 "bla2=no problem"   With (2):  --mode good --status okay --name bro --description very good man dood --config "blablabla=yes" --config2 "bla2=no problem"   Much appreciated!

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


It was then answered on 2016/02/24 at 15:52:52Z, seconds after being marked as duplicate.     How is this possible? Is there a delay between duplicate marking and closure? If so how long is this delay?

Question:   Answer:   The question was closed at 11:57:57 (according to the hover-over-"x-mins-ago" bar) and the answer was posted at 12:16:35. It's a fairly lengthy answer, so it's possible that it was started to be written before it was closed but I swear I've started to answer a question then I got a banner along the top saying "this question has been closed" and the answer was no longer post-able.


Would anyone be so kind as to help me to understand how can I get a null pointer exception here?      @Override     public Collection<? extends GrantedAuthority> getAuthorities() {         Collection<GrantedAuthority> grantedAuthorityCollection = new ArrayList<>();         Collection<UserRole> userRoleCollection = user.getUserRoleList();         if(userRoleCollection != null) {             if (userDetailsService.getAuthorities(userRoleCollection) != null) {             // ^^^ it occurs at the line above ^^^                 grantedAuthorityCollection.addAll(userDetailsService.getAuthorities(userRoleCollection));             }         }         return grantedAuthorityCollection;     }   Here's what I get at run-time:  java.lang.NullPointerException: null     at ua.tucha.passpass.web.security.UserDetails.getAuthorities(UserDetails.java:31)     at org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.createSuccessAuthentication(AbstractUserDetailsAuthenticationProvider.java:225)     at org.springframework.security.authentication.dao.DaoAuthenticationProvider.createSuccessAuthentication(DaoAuthenticationProvider.java:137)     at org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.authenticate(AbstractUserDetailsAuthenticationProvider.java:197)     ...   How can it be? I've just made sure if there's not null in userRoleCollection, the next instruction wouldn't have been executed if there was null, would it?  Thank you very much in advance for your kind help.

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 am wondering whether "remaining" is a dangling participle in the following:  By remaining calm, a solution is usually possible.  I'd appreciate your help.

I've been spotting what seems to me misplaced modifiers in professional writing, so I would love to get some tips on the following examples:        He'd sit until the last moment, watching them draw near.      Isn't "watching them draw near" modifying he? Then shouldn't it come at the very beginning of the sentence? It looks misplaced, but I'm doubting myself since the sentence was in a story written by a professional writer.         There is the sound of rain on the roof, intensifying, hammering at the gutters.      Is it okay if the participle and the noun are separated by a prepositional phrase?        my spirits are dreadful, owing entirely to the Horrors of every night      It seems to me that in this case, the participial clause is describing the state of my spirits being dreadful. Is it possible for a participial phrase to describe not just one word, but the entire clause?         The number of new UC students from other states and nations will continue to increase this fall, extending a trend that university officials say is financially necessary...      This seems to have a similar usage as above.  Would love any kind of input!


I upgraded my distro from 12.04 to 13.10, but it seems to have crashed my machine.  I'm dual-booting, and grub is okay - but my desktop appears with errors.  I can't shut down properly, because the GUI is gone, and an internal error appears upon boot.  I can't get to the terminal without using Ctrl+Alt+F1, and when I shut down from there all clicks are disastrous.  I don't know if I should upload a log (netstart no longer seems to work).  Please help me get my OS back; I have a lot of data stored that I can't afford to replace.

I just installed a new version of Ubuntu and I want to roll it back to the previous version.  How can I do that? Is that even possible?


I was paging through my grammar book and I came across with this sentence:     I was thinking of going to china next year, but it depends on how much money I've got.    I  know ,here, past progressive refers to the future, but I cant figure out why present perfect tense has been used at the end? Does it have a subjunctive mode?  In addition, compare:   I was thinking of going to china next year, but it depends on how much money I will have. I was thinking of going to china next year, but it depends on how much money I have.   In sentence #2, I used the bare infinitive have to imply subjunctive mood as matter of the fact that sentences similar to the highlighted one are extensively used in my native language (Persian) with subjunctive tone of voice.  Would you please help me to understand the difference(s) between these three sentences?

I know this subject was discussed for many times, but I still don't get it..  I've read in a book that we can use "I've got" instead of "I have" for possesion and it gave some examples,      I've got an English book.   I've got a red car.   So I understand that it can be used only for possession of physical objects, but I saw it used in sentences like "I've got something to say", is it correct? I hope it's not a stupid question..Thank you very much!


\item Obtain the one-to-one function $f_1$ and $f_2$ by cutting the graph of $f$ at        a certain point ($x_1$, $y_1$) so that domain of ($f_1$)=($-∞$ , $x_1$] and        domain ($f_2$)=[$x_1$,$+∞$)

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


what do you mean by  DASH? I have not come across this on other operating systems. Some one asked me to help them so I don't know your jargon

I've sent a few mails to the Ayatana mailing list regarding some UI suggestions for Unity, but I'm afraid I keep confusing the right terms for the UI element, so I would like to have some clarification.  Answer Index:


I would like to get time in below format 2020-10-12 10:41:42,526   How can it be done. I tried this but looks not correct date +"%Y-%m-%d %H:%M:%S,%N"

I need to display date and time in desired format in Unix/ Linux. My desired format is: dd/mm/yyyy hh:mm:ss:ms in Unix or Linux. I got close using the following command:  echo $(date +%x_%r)   This returns:  08/20/2012_02:26:14 PM   Any suggestions?


I am having trouble finding an answer to a question i have. I am pretty sure its a relatively simple question with a simple answer but cannot find it.   What i want to know is if you have two infinite sequences(maybe series not sure which is the correct term) if they are both countably infinite can one be larger than the other if one is a subset of the other. a simple example would be.  since all the odd numbers are a subset of all the natural numbers would the natural numbers contain more elements than the odd numbers since the odd numbers are a subset of the naturals?  I know both these sets are infinite but wouldnt the natural numbers be of a higher order than just the odd numbers. common sense tells me there are exactly twice as many natural numbers than odd numbers. but common sense doesn't work as you approach infinity.  Thanks in Advance

I have been studying Cantor's theorem, and I follow entirely that the set of natural numbers $\mathbb{N}$ is countable, as is the set of odd numbers (let's call it $\mathbb{O}$).  I understand his proof that there is a correspondence between the two sets and feel like I could accept that they therefore have the same cardinality based on that ... but ... hold on ...  We know that $\mathbb{O}$ is a subset of $\mathbb{N}$ right? $\mathbb{N}$ certainly contains all of the odd numbers.   We also know that $\mathbb{N}$ contains numbers that are not odd.   So if $\mathbb{N}$ contains all of $\mathbb{O}$ and some other stuff as well then surely it would be totally justified to argue that $\mathbb{N}$ is larger than $\mathbb{O}$?


I removed some fields from phpmyadmin; now I get the following error from Drupal:      PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'restech1_newDrupal.field_data_field_contactus_images' doesn't exist   I removed the contactus_images field together other fields I wasn't using, in order to make space on my server.   How do I get the site to come back?

How does one remove a field from a node programmatically? I have a migration in hook_update_N that moves the contents from a a field into a custom table. After that migration, I want to remove the field in that same function.  Are there any field API's that cater removing fields?  Edit, Solution: Because the answers lack actual code, here is what I did to move fields from the $users into my own records and subsequently remove the field from the database;  function my_module_update_7005(&$sandbox) {   $slice = 100;   //Fetch users from database;   if (!isset($sandbox['progress'])) {     $sandbox['progress'] = 0;     $sandbox['current_uid'] = 0;     // We'll -1 to disregard the uid 0...     $sandbox['max'] = db_query('SELECT COUNT(DISTINCT uid) FROM {users}')->fetchField() - 1;   }   if (empty($users)) {     $sandbox["current_uid"] += $slice;   }   $users = db_select('users', 'u')     ->fields('u', array('uid', 'name'))     ->condition('uid', $sandbox['current_uid'], '>')     ->range(0, $slice)     ->orderBy('uid', 'ASC')     ->execute();   //Loop trough users;   foreach ($users as $user) {     $foo = new Foo();     // Warning: drupal's fields return mixed values; e.g. NULL versus an int.     $foo->debits = (int) $user->user()->field_credits["und"][0]["value"];     $foo->save();      $sandbox['progress']++;     $sandbox['current_uid'] = $user->uid;   }    $sandbox['#finished'] = empty($sandbox['max']) ? 1 : ($sandbox['progress'] / $sandbox['max']);    // Remove the field.   field_delete_field("field_credits"); //note that the name for Foo is field_foo   field_purge_batch($sandbox['max']+1);//Drupal seems to have an offbyone problem. }


My partner needs to get a visa.  From all I read it's a transit C-1 that is required.  I have flight details completed and it asks for location of stay in US.  Then contact in US. However we are only in the airport to get connecting flight.    Can anyone advise what I should be selecting or do I just type does not apply?

I'm a Canadian citizen with a Canadian passport. I booked a flight with American Airlines to Mexico City From Toronto Pearson and it says that "Passenger details are needed to check in".  Flight 1: YYZ -> DFW -> MEX Flight 2: MEX -> DFW -> YYZ     They already took my name, gender and such. It is now asking for my passport number and expiry date. That all seems reasonable. However, when I enter that I am a Canadian resident it asks for:  1) Street or hotel in US 2) City in US 3) State in US    My trip to DFW is only for a connecting flight. The fields are required so I can't submit my passport information without filling this in.    Is there something I'm missing?


I have moved wp-config.php but my file structure is as given below:  public_html --abccom --applecom --wp-config.php   abcom and applecom folder has  wordpress websites both As advised, I have moved wp-config.php outside abccom for security, but now when I need to do the same for applecom, how can I achieve it?

One of the most common security best practices these days seems to be . I've never really found a good explanation for that, but I'm assuming it's to minimize the risk of a  malicious or infected script within the webroot from reading the database password.  But, you still have to let WordPress access it, so you need to expand open_basedir to include the directory above the document root. Doesn't that just defeat the entire purpose, and also potentially expose server logs, backups, etc to attackers?  Or is the technique only trying to prevent a situation where wp-config.php would be shown as plain-text to anyone requesting http://example.com/wp-config.php, instead of being parsed by the PHP engine? That seems like a very rare occurance, and it wouldn't outweigh the downsides of exposing logs/backups/etc to HTTP requests.  Maybe it's possible to move it outside the document root in some hosting setups without exposing other files, but not in other setups?    Conclusion:  After a lot of back-and-forth on this issue, two answers have emerged that I think should be considered the authoritative ones. Aaron Adams makes a good case in  wp-config, and chrisguitarguymakes a good . Those are the two answers you should read if you're new to the thread and don't want to read the entire thing. The other answers are either redundant or inaccurate.


I saw on Richard Hammond Builds A Universe on BBC2 a few days ago that you are always at the center of the universe wherever you are.  Surely this is illogical, because you could never get to the edge of the universe.  If I am in the center, then what about that object 10 meters away. Is that at the centre too? How is this possible?  What if I am driving for example. Does this mean that I am moving the universe while I stay still?  Thanks

If the big bang was the birth of everything, and the big bang was an event in the sense that it had a location and a time (time 0), wouldn't that mean that our universe has a center?  Where was the big bang? What is there now? Are we moving away from the center still? Are these even valid questions?


When I try to install PHPUnit in docker, I got the error message but mcrypt seems to be installed. What did I miss ? $ composer require phpunit/phpunit=3.7.* --dev The requested PHP extension ext-mcrypt * is missing from your system. Install or enable PHP's mcrypt extension.  $ yum list installed | grep mcrypt libmcrypt.x86_64                 2.5.8-9.el6                       @epel libmcrypt-devel.x86_64           2.5.8-9.el6                       @epel php-mcrypt.x86_64                5.3.3-5.el6                       @epel  CentOS release 6.10 (Final) PHP 5.3.29

It's got to be somewhere in the phpinfo() dump, but I just don't know where.  Is it supposed to be under the "Additional Modules" section?  Somewhere else?  I'm trying to figure out why some extensions don't appear to be loaded, but I don't even know where I should be looking.


I have MySQL field which contains plain text Cyrillic characters (ex. Широка поляна). Collation is utf8_general_ci.  When I pull out this content with MySQL query and try to output it with php I always get ???? symbols. HTML encoding is utf8, document encoding is utf8, mb_detect_encoding() shows ASCII for the string but none of the PHP / MySQL convert functions turns it into something readable.

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


Is it possible to not smash the laboratory wall for the achievement Another Way In?      Another Way In   Start a game without breaking the laboratory wall.

There's a new achievement and I'm stumped as to how to get it:     Start a game without breaking the laboratory wall   I assume it has something to do with the new Gadgets but none of them sound like they'd help. How do I get this achievement?


It is evident that expressions like "as has been seen" make reference to something already mentioned before. However, why is there no pronoun? why not, for instance, "as IT has been seen"? On the other hand, what kind of grammatical category does it belong to?

My senior English teacher was a tad bit confused where the subject for was is in this sentence:     As was traditional for unmarried women, Jane lived at home her entire life.


How can I prove that if $X_1,...,X_n$ are iid $Bernoulli(p)$, then $X_1+...+X_n$ is $Binomial(n,p)$ ?    Attempt  $$\mathbb P\{X_1+...+X_n=k\}=\sum_{x_1+...+x_n=k}f_{X_1,...,X_n}(x_1,...,x_n)$$ $$=\sum_{x_1+...+x_n=k}f_{X_1}(x_1)...f_{X_n}(x_n)$$ But now, I have difficulty to conclude. How can I do ?  I also did by induction, and it worked, but I really would like to use this method.

Let $\{X_n, n \geq 1\}$ be iid Bernoulli random variables with $\Pr(X_1 = 1) = p = 1 - \Pr(X_1 = 0)$ and let $S_n = \sum\limits_{i=1}^n X_i$ be the number of successes in $n$ trials. Show $S_n$ has a binomial distribution by the following methods:  1.) Prove for $n\geq0,$ $1\leq{k}\leq{n+1}$  $$\Pr(S_{n+1} = k) = p\Pr(S_n = k - 1) + q\Pr(S_n = k)\text{ where }q = 1-p.$$  2.) Solve the recursion using generating functions.  For the first method, I think I need to use convolution of $n + 1$ Bernoulli rvs, but I cannot immediately see the progression. For the second method, I don't exactly understand how to proceed either. This is problem 1.2 from Resnick's Adventures in Stochastic Processes.


I'm experimenting with electro vibrations. This principle is about simulating textures using low current electricity on an insulated conductive surface (see Wikipedia: ).  I've started to use some EL-wire IC's to create a AC signal from a DC powersupply since i need a high voltage AC signal (max 115 vpp). With the IC's i got some results but i'd like to have more freedom in the output (the ic gives a fixed voltage and frequency).   Actually what i'm looking for is a high voltage, low current signal generator circuit. 80-115 Vpp (AC) and 80-400 HZ. I'd like to control it with arduino. So ideally it would be a way to amplify and convert the 0-5 DC signal to a 80-115Vpp AC signal.  What's the best way to do this?  Cheers,

For my project, I'm trying to work with the principle of electrovibration. This principle is about simulating textures using low current electricity on an insulated conductive surface ().  In order to do this, I will be experimenting with generated AC signals of 80 to 160 Vpp at 60Hz to 400Hz. I will do this by using an DC - AC converter, usually used for EL lamp applications.  My only concern is how to limit the current coming from the converter. Are the techniques for limiting AC current the same as DC, by using a simple resistor? Or is it, as I expect, more complex?  I need to limit the current to 0.5mA, for safety reasons.


I've been looking at some proofs of derivatives of functions and the teacher who made it used this in his proof:  $$ \lim_{u \to 0}((1+u)^{\frac{1}{u}})=e\ $$  I can see that this is true by substituting small values for u but why is this true and how do I prove it?  I would thank you if you could explain on more of a basic level, since I am quite a beginner here :)  Thanks in advance!  PS Sorry for my sloppy Enlgish

I dont get it, if I look at $$\lim \limits_{n \to \infty}\left(1 + \frac{1}{n}\right)^n = e$$    It seems like it should be $1$ because $1 \over n$ is almost zero and $1^\infty$ is still $1$


Website is being indexed by Google twice.  Both indexes have the right SEO information for the home page, such as title and description. However for the sublinks there are two versions, one version of the indexed site that has the correct sublinks and sublink information, and the other version that has all sublinks pointing to the home page with the format of these wrong sublinks being http://example.com/#random%20text  I have gone into webmasters and chosen my prefered domain, I have tried removing these wrong sublink pages, but due to redirecting to home, it stops home from being indexed, so I reverted this change, I have tried demoting the sublinks, it did not work, I've tried adding <meta name="fragment" content="!"> to my header, it did not work, I have tried disabling all plugins on WordPress to see if that was the reason, it was not.  I've everything I can think of and would really appreciate some help as to how I can stop Google indexing one version of my website with all the wrong sublinks.  If it's of any help, when I search for the business website name on Google as "businessexample" it shows the broken link index version, and when I search as "business example" it shows the correct version.

As that title says, my website is being indexed by Google twice.  Both indexes have the right SEO information for the home page, such as title and description. However for the sublinks there are two versions, one version of the indexed site that has the correct sublinks and sublink information, and the other version that has all sublinks pointing to the home page with the format of these wrong sublinks being http://example.com/#random%20text  I have gone into webmasters and chosen my prefered domain, I have tried removing these wrong sublink pages, but due to redirecting to home, it stops home from being indexed, so I reverted this change, I have tried demoting the sublinks, it did not work, I've tried adding <meta name="fragment" content="!"> to my header, it did not work, I have tried disabling all plugins on WordPress to see if that was the reason, it was not.  I've everything I can think of and would really appreciate some help as to how I can stop Google indexing one version of my website with all the wrong sublinks.  If it's of any help, when I search for the business website name on Google as "businessexample" it shows the broken link index version, and when I search as "business example" it shows the correct version.  Update : Still not able to figure this out, any help is welcome.


I am building a contacts app and have created a database for it. Each time I run it, it shows the exception below.   Sample of logcat error:  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.util.ArrayList.size()' on a null object reference         at com.example.joey.sqlite.MainActivity.onResume(MainActivity.java:48)         at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1257)         at android.app.Activity.performResume(Activity.java:6076)         at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3039)         at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3081)          at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2447)          at android.app.ActivityThread.access$800(ActivityThread.java:156)          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)          at android.os.Handler.dispatchMessage(Handler.java:102)          at android.os.Looper.loop(Looper.java:211)          at android.app.ActivityThread.main(ActivityThread.java:5389)          at java.lang.reflect.Method.invoke(Native Method)          at java.lang.reflect.Method.invoke(Method.java:372)          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)    How can I resolve it?  The error is reported to be in the for loop:  @Override protected void onResume() {      DBHelper dbHelper = new DBHelper(this);      namesList = new ArrayList<String>();     for (int i=0; i< dbHelper.getAllContacts().size();i++){         namesList.add(dbHelper.getAllContacts().get(i).getName());     }      adapter = new ArrayAdapter(getApplicationContext(),android.R.layout.simple_list_item_1,namesList);      list.setAdapter(adapter);     super.onResume(); }   Sample For Database Read Method:  public ArrayList<Contact> getAllContacts() {     SQLiteDatabase db = this.getReadableDatabase();     ArrayList<Contact> contactArrayList = new ArrayList<Contact>();      Cursor cur = db.rawQuery("select * from " + TABLE,null);     cur.moveToFirst();     while (cur.isAfterLast() == false) {         try {             Contact contact_new =  new Contact();             contact_new.setName(cur.getString(cur.getColumnIndex(NAME)));             contact_new.setEmail(cur.getString(cur.getColumnIndex(EMAIL)));             contact_new.setPhone(cur.getString(cur.getColumnIndex(PHONE)));              contactArrayList.add(contact_new);             cur.moveToNext();              return contactArrayList;          } catch (Exception ex) {             ex.printStackTrace();             return null;         }     }     return null; }

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 posted a question on  a few days back on a weekend and it has received no responses/views.  Can I delete that question and undelete it again to make it appear in the "Newest Questions" feed?  Will undeleting a question make it appear in the newest questions feed?

What can cause a question to be "bumped" to the first page in the Active tab of a Stack Exchange site? (Changing the "Last Active" date.)  .


I have been trying to shrink my C: drive partion but currently to no avail. I am unsure about using 3rd party software to do it (such as  or ). So I have a 1TB harddrive with 4 partions. Running Windows 8.1.   My main goal is to get a 40GB partion for a dual boot of Linux. So I first tried to shrink the C: but the max I could shrink it by was only 9000MB so I followed the instructions at  (disabling paging, defrag and disabling hibernation) . This enabled me to shrink it by a maximum of 400000MB(ish). I went ahead and tried to shrink the partion by 40000MB but it came up with the error saying there is not enough space.  Below is a screenshot of the current partions:

I have just bought an HP laptop with Windows 7 (64 bit). It has a 500 GB HDD with three partitions: a small hidden system partition, a 12 GiB HP recovery partition, and a 450 GiB C: boot partition.  I would like to split this large C: partition into two partitions, leaving only 100 GiB for the system, and giving the rest to a new data partition.  Although the Windows built-in Disk Management utility has an option to shrink the bootable partition, it only allows me to shrink it roughly by half, even though only 20 GiB on the partition is used. As far as I understand, system unmovable files lie in the middle of the partition, preventing Disk Management utility to do what I want.    And since new HP laptops don't come with OS installation disks (they only allow you to create recovery disks yourself), I can't just repartition HDD and then reinstall OS.  So, is there a way to shrink the C: bootable partition and preserve Windows 7 working?  P.S.: I have tried to use the third-party  utility, and after shrinking the partition, Windows 7 stopped booting, with a . System recovery didn't work, and I had to do factory recover. Since this is a long process, I would like to avoid doing it again :) So, please, suggest only proven solutions.


I know  that uses $x={\sqrt{2}}^{\sqrt{2}}$ to prove that there must exist an irrational to an irrational power that evaluates to a rational. But I don't know if $x$ itself is known to be irrational or rational.  Could someone enlighten me? Thanks!

The fact that there exists irrational number $a,b$ such that $a^b$ is rational is proved by the law of excluded middle, but I read somewhere that irrationality of $\sqrt{2}^{\sqrt{2}}$ is proved constructively. Do you know the proof?


Just upgraded to 13.10, no desktop icons/menu, just the wallpaper.  I've tried :  sudo apt-get update sudo apt-get install --reinstall ubuntu-desktop sudo reboot  sudo apt-get upgrade sudo apt-get dist-upgrade

When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.


Tried  but no dice.  Also tried followed the steps  (which look similar) but on the last step I get:  $ sudo modprobe -v wl insmod /lib/modules/4.10.0-32-generic/updates/dkms/wl.ko  modprobe: ERROR: could not insert 'wl': Required key not available   I'm not getting any kind of connectivity, and have to connect to my router with ethernet.  Here's my dpgk info:  $ dpkg -s bcmwl-kernel-source Package: bcmwl-kernel-source Status: install ok installed Priority: optional Section: admin Installed-Size: 7870 Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com> Architecture: amd64 Source: bcmwl Version: 6.30.223.271+bdcom-0ubuntu1~1.1 Replaces: bcmwl-modaliases Depends: dkms, linux-libc-dev, libc6-dev Conflicts: bcmwl-modaliases Description: Broadcom 802.11 Linux STA wireless driver source  This package contains Broadcom 802.11 Linux STA wireless driver  for use with Broadcom's BCM4311-, BCM4312-, BCM4313-, BCM4321-,  BCM4322-, BCM43224-, and BCM43225-, BCM43227- and BCM43228-based  hardware. Modaliases: wl(pci:v000014E4d00004311sv*sd*bc02sc80i*, pci:v000014E4d00004312sv*sd*bc02sc80i*, pci:v000014E4d00004313sv*sd*bc02sc80i*, pci:v000014E4d00004315sv*sd*bc02sc80i*, pci:v000014E4d00004727sv*sd*bc02sc80i*, pci:v000014E4d00004328sv*sd*bc02sc80i*, pci:v000014E4d00004328sv*sd*bc02sc80i*, pci:v000014E4d00004329sv*sd*bc02sc80i*, pci:v000014E4d0000432asv*sd*bc02sc80i*, pci:v000014E4d0000432bsv*sd*bc02sc80i*, pci:v000014E4d0000432csv*sd*bc02sc80i*, pci:v000014E4d0000432dsv*sd*bc02sc80i*, pci:v000014E4d00004365sv*sd*bc02sc80i*, pci:v000014E4d00004353sv*sd*bc02sc80i*, pci:v000014E4d00004357sv*sd*bc02sc80i*, pci:v000014E4d00004358sv*sd*bc02sc80i*, pci:v000014E4d00004359sv*sd*bc02sc80i*, pci:v000014E4d00004331sv*sd*bc02sc80i*, pci:v000014E4d000043a0sv*sd*bc02sc80i*, pci:v000014E4d000043B1sv*sd*bc02sc80i*) Original-Maintainer: Alberto Milone <alberto.milone@canonical.com>   Not sure what other information I should provide.

This issue happens only on UEFI systems with enabled Secure Boot.  When I try to install DKMS modules like VirtualBox, Nvidia, or Broadcom drivers, they do not install and I get Required key not available when I try to modprobe them.  VirtualBox complains that vboxdrv is not loaded.  Broadcom wl driver is shown in lspci -k as a kernel module but is not in use. sudo modprobe wl throws Required key not available.  Also this issue may happen when I install some kernel modules from git sources.  This issue may appear after a kernel update as disabled wireless adapter, black screen after a reboot, etc.   How can I fix it?


There is a book series where the main characters (one boy and one girl) have powers. If I remember correctly, the boys powers are associated with the smell of oranges, and the girls powers are associated with the smell of vanilla. What book is this?

As a child, I read a book that I can't seem to remember. All I seem to get from my memories are pictures and scenarios from my imagination while reading the book. I remember the book including Bastet, the cat goddess, a type of tunnel where they went to an underground place (I think), a boy and a girl (possibly) walking in a type of room or something, and a part where there might be an owl involved. I read the book definitely after 2010 but I am more than sure that it was written before that, possibly. In the part where they were in a type of room, I think I remember hieroglyphs floating around in the air. That is kind of all I remember from the book. Some of this information may be wrong and confusing but I think that is all I remember from the book. I really want to read it again because as I remember, it was an amazing book.


For two square matrices $A$ and $B$ of the same size, we have the identity $$ \det\left[ \begin{matrix} A & B \\ B & A \end{matrix} \right] \ = \ \det\left( A + B \right) \det( A - B ) \ . $$ This is supposed to hold even when the matrices are non-commuting ie. $A B \neq BA$. In the case that $AB=BA$, I can see how the above follows from the identity $$ \det\left[ \begin{matrix} A & B \\ C & D \end{matrix} \right] \ = \ \det(D) \det\left( A - B D^{-1} C \right) $$ by taking $(C,D) \to (B,A)$ and mutiplying the argument of the determinants together, leads to $$ \det\left[ \begin{matrix} A & B \\ C & D \end{matrix} \right] \ \to \ \det(A) \det\left( A - B A^{-1} B \right) = \det\left( A^2 - B A^{-1} B A \right) = \det\left( A^2 - B^2 \right) =  \det\left( A - B \right)\det\left( A + B \right) $$ but the above proof relies heavily on $AB=BA$. How do you see this identity is true in the case that $AB\neq BA$?

The  mentions the following matrix identity $$\det\begin{pmatrix}A&B\\B&A\end{pmatrix}=\det(A+B)\det(A-B),$$ valid for squared matrices $A$ and $B$ of the same size.  How is this result proved?


I am an engineer and not a physicist. I am unable to understand why SuperNova happen.  I understand that when the core is composed of high atomic number of elements like Iron and further fusion is not possible. The core collapses under its gravity.  At this point the outer layer burst in a huge supernova. I am unable to understand why the outer layer just burst out in this supernova. Leaving behind a Neutron star or a black hole.

This is really bugging me. When you look up some educational text about stars life, this is what you find out:   Gravity creates the temperature and pressure to start fusion reactions. The fusion proceeds to heavier and heavier cores ending with iron, which remains in the centre of the star. One moment, all light cores are depleted and the gravity wins over the power of the fusion reactions, now absent. The core of the star collapses into high density object, which may vary depending on the star mass. And the top layers of the star explode.   And I just cannot find clear explanation why. According to what I imagine, the top layers of the star should just fall into the collapsing core.  Is that because of the 3rd Newtons rule?  Or do the stars have some need to end with a cool boom?


Consider this script:  \documentclass{report} \usepackage{subfig} \usepackage{graphicx} \usepackage{lipsum} \begin{document} \begin{figure}[htp]   \subfloat[\lipsum[1]]{     \includegraphics{example-image-a}   } \end{figure} \end{document}   I would like to use lipsum in the caption of the subfloat. I get the following error:  ! Argument of \lipsum  has an extra }. <inserted text>                  \par  l.8   \subfloat[\lipsum[1]]                            {   What is wrong?

LaTeX seems to be having problems handling nested optional arguments. I've included a minimal code example that generates the error:  \documentclass[12pt,oneside]{book} \begin{document}  \newcommand{\termbad}[2][]{#2#1} \newcommand{\termgood}[2][]{#2#1}  \newcommand{\up}[1]{#1} \newcommand{\dd}[1][]{#1}  \termgood{\up{Tart}}{Pop} \termbad[\up{Tart}]{Pop}      \termgood{\dd[Tart]}{Pop} \termbad[{\dd[Tart]}]{Pop} %\termbad[\dd[Tart]]{Pop}   \end{document}   If you run this code, it works. If you remove the % in the second to last line, it fails with:  Runaway argument?  Tart{Pop} \par \par \end {document}  !File ended while scanning use of \dd.   After further tinkering, I have discovered the problem: LaTeX is reading the ] for the inner optional argument as the end of the outer optional argument and then passing a malformed argument in. So it is passing in \dd[Tart as the optional argument to \termbad instead of \dd[Tart].  This still feels like a bug to me. Nesting braces in arguments works, brackets should as well. The following are workarounds:   Enclose the inner optional argument in braces (as in the line before %). Redefine your inner function to require its argument instead of using optional arguments. Redefine your outer function to require its argument instead of using optional arguments.   Any one of the three works around the issue.  (Reposted here; question was originally posted to stackexchange and then closed instead of being migrated.)


From last 2 days I have edited almost 30-35 question but none of them is being approved. Is there a limit on edit or any other reasons Why my edits are not being accepted.

When clicking "edit" I see:  Your edit will be placed in a queue until it is peer reviewed. We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.  Like:     Likewise, when I am not logged in, clicking "improve this question" or "improve this answer" shows:  You are not . Your edit will be placed in a queue until it is .  And when I click 'Save', I get:  Thanks for submitting an edit. It is only visible to you until it's been approved by trusted community members  Like:     Who can suggest an edit? Where do suggested edits go? Who can vote on a suggested edit? How do suggested edits get reviewed? Can I earn reputation? What about abuse or bad edits? Sometimes the Community user approves or rejects my edit. Why is that? When can I not suggest an edit? Is there a minimum change requirement for a suggested edit? How do I check my suggested edit history? I disagree with the reasons why my suggested edit was rejected. What can I do? How do I know whether there are edits waiting for review? Someone suggested an edit to my own post, and the reviewers took the wrong action. What can I do? Are tag wikis included in this scheme? What do the "Improve Edit" and "Reject and Edit" buttons do? Why are apparently valid links to rejected edits resulting in 404 errors?   For more information about editing, see "" in the .