What should I do about upvoted, inactive, unanswered questions that I'm also trying to find the answer for?

has been suggested as a possible duplicate. However, my question points out a few specific scenarios that could be worth discussing.  is also relevant, as it's about bringing attention to questions. I occasionally research a programming problem, trying to solve the problem myself, and come across a Stack Overflow question, of which I'm not the author, about the problem I'm trying to solve. However, it is:  Unanswered  Inactive for months or years  Upvoted (so the Community user won't auto delete it)  No answered duplicates   And I:  Do not have enough reputation to offer a bounty  Do not see any ways to edit and improve the post   Put another way, the chance that question will gain any activity by itself in a reasonable timeframe if at all is not worth discussing, and I do not have any means to promote the question myself. So the question already exists, so if I try asking it myself, mine might get closed as a duplicate, but the existing question is useless, as it is unanswered. Also I haven't really seen the Community user's bump to the homepage feature in action much or at all on Stack Overflow. In this case, what should I do? Should I post the question in such a case anyway, despite the duplicate? Would the question be closed as a duplicate of the unanswered question?


What are some unintuitive consequences if we assume that axiom of choice is wrong?

Accetping axiom of choice gives rise to all sort of paradoxes. What if we assume the contrary?


Why is JDI's invokeMethod exponentially slower as the number of parameters increases?

com.sun.jdi.ClassType.invokeMethod() takes < 1ms on a dummy method with no parameters at all. With 6 parameters, it takes 3-4ms (the method implementation does not change, the parameters are just passed to the method but are not used at all). For 20 params it is like 16-17ms. So it takes 16-17ms to pass these parameters to the method which is huge in my opinion. This is my method which is called: public static void dummy(Object a1, Object a2, Object a3, Object a4, Object a5, Object a6){ //some basic operations which do not depend on the params, can be replaced with Thread.sleep(), or even left empty }  and this is how I call it: List<Value> values = new ArrayList<>(map.values()); long l = System.currentTimeMillis();  invokeMethod(threadRef, dummyMethod, values, ObjectReference.INVOKE_SINGLE_THREADED);     System.out.println("time:"+ (System.currentTimeMillis() - l));  I also tried with Varargs, the result is even worse. Also, is there a workaround so that I can pass all my params to the method without this huge time overhead(for example using some sort of wrapper)? Update:  I ran another benchmark where I call invokeMethod several thousand times and calculate the total time it takes. The difference between the no-param and multi-param version is too large to be because of microbenchmark bias.


Identify self closing tag of XML in Java

I am reading an XML file with a Java project. Everything is alright if the tags are regular i.e. with start tag and end tag. Example:  <Packages>     <Number>20</Number>     <Marks_one>ONE</Marks1_one>     <Marks_two>         <null/>     </Marks_two>     PX     <name>Pallet </Kind> </Packages>   All of the value of these tags can be read including  whice is . But in the same file I have  like this:  <Packages>     <Number/>     <Marks_one>ONE</Marks1_one>     <Marks_two>         <null/>     </Marks_two>     PX     <name>Pallet </Kind> </Packages>   Here  is self closing and also doesn't have any attribute. Java is giving exception here and exception is null. I shall omit the tag if it is self closing. Please tell how to find out if that tag is self closing or regular?   Code for parsing XML is given below:  NodeList Packages_List = Item_Element.getElementsByTagName("Packages"); System.out.println("Packages_List.getLength() : "+Packages_List.getLength());Node Packages_Node = Packages_List.item(0);if(Packages_Node.getNodeType() == Node.ELEMENT_NODE){ Element Packages_Element = (Element)Packages_Node;  NodeList Number_of_packages_List = Packages_Element.getElementsByTagName("Number");  Element Number_of_packages_element =(Element)Number_of_packages_List.item(0); NodeList text_Number_of_packages_List = Number_of_packages_element.getChildNodes(); Number=((Node)text_Number_of_packages_List.item(0)).getNodeValue().trim();  System.out.println("Number : "+Number);   }


Show vote buttons for historical notice locked posts

On the UX Stack Exchange, recently there was a .  As shown , the voting buttons are not there, unlike other posts:        , it says that because nobody can vote, it doesn't show it. The accidental discovery could show a message like You can't vote on locked posts, kind of like the 'you need 15 rep', or 'you can't vote on your own posts' messages. While the rationale is 'it's a global state', it's inconsistent with the rest of the site.  Can we please put the vote arrows back in those posts, same way we have in other locked posts?


I want to make this for my cover page, to write over an image. Any advice will be very well received.


How does everyone in Star Wars understand droidspeak?

All throughout the Star Wars movies, we see the droids emit several beeps and whirs, and the humans reply to the droid as if it were a normal conversation. How can every character in Star Wars fluently understand droidspeak? We know that Anakin Skywalker could speak several languages by the age of 9, including droidspeak. Is this language just something standardly taught to young children across the galaxy? Droidspeak is a complicated language. Are children in Star Wars born knowing it? Do they learn it like their own language, from their parents and surroundings? (This question has been associated with "How do people understand astromech droids?". I am asking about all types of droids and their language droidspeak (or Binary), not specifically astromech droids, although the questions are fundamentally similar) **edit: I have found evidence for this question in the show Star Wars Rebels (which is canon). In one scene, Zeb says to Ezra "Wait, you actually understand that glorified beeping garbage can?" (referring to a droid) and Ezra responds: "Yeah, sort of. I'm learning." which implies that droidspeak can be learned, but is not widely known. **


Beamer consists of multiple frame layouts

I am creating a beamer that consist of frames using certain layout repeatedly.  To put it simple, let's say my beamer consists of 3 types of frames   A: only a giant word at the dead centre of the frame B: a big pictures with a big (inspirational) word under C: a quotation at left, and picture of that person at right   I wish to make some kind of template so that I can later use \begin{frame}[A] ... \end{frame} so that all the setting (font size, colour) are pre-set once and for all, just like MS powerpoint slide layout function.     Is it possible?


How can I set Hibernation in Ubuntu 18.04 LTS (laptop)?  When I open the Power option > When the Power Button is pressed, I just see the following options:   Suspend Power OFF Nothing   But does not show Hibernate.


Is it bad to have a 'coming soon' page before launch?

I bought a domain name and for the moment the page only says something like 'this domain is registered' but does it have a negative impact on SEO if I keep this page for some months, before I'm ready to launch the website? Will Google blacklist the website because it considers that it has no content?


True or False and why ? basic integration

$$\int_0^2f(x)\,\mathrm dx=\int_0^2 f(t)\,\mathrm dt.$$  I would say true because a&b = a&b and it would not make a change if is x,d,f,q,w,t it will logically be all the same, am I right ? but because it is MATH not logic so everything could be unexpected!


Replacing all null values from attribute table with zeros in QGIS

In QGIS 1.8 I have a new column in my attribute table with a lot of NULL values and I want to replace all them to zeros. How can I do that in field calculator?


I'm developing onto Arduino and sometimes the USB port that is being used stops working. Then I need to plug the device into another USB port. Once all the USB ports stop working I have to restart the machine which is really annoying.  As far as I remember there is a command which is able to restart the USB subsystem individually but I can't remember. How can I restart USBs without restarting the entire system?  I'm using macOS Sierra.  This is different to the question  as I need software-only solution as my USB ports get frozen - which means they stop working until full system restart. There must be a way of restarting the USB subsystem individually.


I have written a package and placed it in the same directory as e.g. latex.ltx. However, TeXShop just won't load it, or rather, XeLaTeX and pdfTeX called through TeXShop won't. If I, however, on the file not found error, type:  /usr/local/texlive/2013/texmf-dist/tex/latex/base/mworx.sty   on the Console, the file is found and loaded. And that path is the same as to size10.clo, the first file I see loaded. Why exactly is XeLaTeX doing what appears to be looking for the file only in the .tex file's directory?


How could Sirius buy a broomstick for Harry?

I don’t understand how Sirius managed to buy Harry a firebolt when he was a widely known mass murderer. I recall them mentioning that they took the gold from Sirius’ vault and had it shipped to him. However, how do you buy something with just your vault number? I just don’t buy the Goblins would be so lax on security.  Also you’d think someone would have alerted the Ministry if a mass murderer who broke out of Azkaban is making accessing his vault.  Is there something in the book I’m missing?


Does the 40K universe have an equivalent of Kevin Feige?

Part of the success of the MCU has been the hand of Kevin Feige overseeing the various projects ensuring continuity.   Do Games Workshop/Black Library have a similar role? It certainly feels in recent years that the books have become more in sync, in particular with characters and events in the Horus Hersey books feeding into the more recent (timeline wise) stories, with characters and events being referenced back and forth.


A vertical thermally insulated cylinder of volume $V$ contains $n$ moles of an ideal monoatomic gas under a weightless piston. A load of weight $W$ is placed on the piston as a result of which the piston is displaced by a distance $h$. Determine the final temperature of the gas. Take area of cross section as $A$ and atmospheric pressure $P0$.   My approach:I conserved the total number of moles before and after attaing final equilibrium.I also applied the Work Energy theorem on the piston:Work done by(gas+atmosphere+gravity)=0. So I'm getting the work done by gas as -(P0*A*h+Mgh) which is equal to the negative of the change in internal energy of the gas. However the author gives the equation:Mgh=change in internal energy of gas. Why has he skipped the work done by the atmosphere. Can I prove mathematically that only the work done by gravity goes into change in internal energy of gas?Is it because the system was initially in equilibrium under atmospheric pressure?


I have the feeling that luggage is more closely associated with vacation travel, whereas baggage is for general transportation.  Or... are they just exact synonyms?


Why isn't average speed defined as the magnitude of average velocity?

Speed is usually defined as the magnitude of (instantaneous) velocity. So one could assume that average speed would be defined as the magnitude of average velocity. But instead it is defined as   $$s_{\textrm{average}} = \frac{\textrm{total distance traveled}}{\textrm{total time needed}}$$  which generally speaking is not equal to the magnitude of the corresponding average velocity.   What historical, technical or didactic reasons are there to define average speed this way instead of as the magnitude of average velocity?


Let $F$ be an algebra. Prove that $\forall A\in\sigma(F), \varepsilon>0, \exists B\in F\mid\mathbb P((A\setminus B)\cup(B\setminus A))< \varepsilon$.

I tried approaching the problem by defining $S = \{A\in\sigma(F) : \forall\varepsilon >0 \exists B\in F\mid\mathbb P((A\setminus B)\cup(B\setminus A))<\varepsilon\}$ and then showing that $S$ itself is a $\sigma$-algebra that contains $F$ and thus it must be $\sigma(F)$.  I was able to show that $\Omega\in S$ and that $\forall A\in S, \overline{A}\in S$. And that $F\subseteq S$. But I got stuck trying to show that $S$ is closed under countable union. I would love help in proving the last part of if someone has another approach, I would love to hear it.


Proof by Induction: Solving $1+3+5+\cdots+(2n-1)$

The question asks to verify that each equation is true for every positive integer n.   The question is as follows:  $$1+ 3 + 5 + \cdots + (2n - 1) = n^2$$  I have solved the base step which is where $n = 1$.  However now once I proceed to the inductive step, I get a little lost on where to go next:  Assuming that k is true (k = n), solve for k+1:  (2k - 1) + (2(k+1) - 1) (2k - 1) + (2k+2 - 1) (2k - 1) + (2k + 1)   This is where I am stuck. Do I factor these further to obtain a polynomial of some sort? Or am I missing something?


I'm using the  for quite a long time; but after exporting my key storage and gpg keys to another machine I see following output:  $ gpg --list-key /home/shved/.gnupg/pubring.gpg ------------------------------ pub   2048R/FA829B53 2015-04-28 uid       [ultimate] Yury Shvedov (shved) <shved@lvk.cs.msu.su> sub   2048R/74270D4A 2015-04-28   My key imported and trusted, but not usable:  pass insert test Enter password for test:  Retype password for test:  gpg: 2048R/FA829B53: skipped: No public key gpg: [stdin]: encryption failed: No public key fatal: pathspec '/home/shved/.password-store/test.gpg' did not match any files   What can I do to use my key again?


I have two checkboxes in a lightning component, when we click on the first checkbox it marks true to the other checkbox, it works well only with the UI tags but doesn't work when I convert it to lightning tag  <ui:inputCheckbox aura:id="box3" change="{!c.selectAll}"/>  <ui:inputCheckbox aura:id="boxPack" value=""                                                          change="{!c.checkboxSelect}"/>   below are the lightning tags  <lightning:input type="checkbox" aura:id="box3" onclick="{!c.selectAll}"/>  <lightning:input type="checkbox" aura:id="boxPack" value=""                                                          onclick="{!c.checkboxSelect}"/>   controller  checkboxSelect: function(component, event, helper) {         // get the selected checkbox value           var selectedRec = event.getSource().get("v.value");         // get the selectedCount attrbute value(default is 0) for add/less numbers.          var getSelectedNumber = component.get("v.selectedCount");         // check, if selected checkbox value is true then increment getSelectedNumber with 1          // else Decrement the getSelectedNumber with 1              if (selectedRec == true) {             getSelectedNumber++;         } else {             getSelectedNumber--;         }         // set the actual value on selectedCount attribute to show on header part.          component.set("v.selectedCount", getSelectedNumber);     },      selectAll: function(component, event, helper) {         //get the header checkbox value           var selectedHeaderCheck = event.getSource().get("v.value");         // get all checkbox on table with "boxPack" aura id (all iterate value have same Id)         // return the List of all checkboxs element          var getAllId = component.find("boxPack");         // If the local ID is unique[in single record case], find() returns the component. not array            if(! Array.isArray(getAllId)){             if(selectedHeaderCheck == true){                  console.log('true');                 component.find("boxPack").set("v.value", true);                 component.set("v.selectedCount", 1);             }else{                 component.find("boxPack").set("v.value", false);                 component.set("v.selectedCount", 0);             }         }else{             // check if select all (header checkbox) is true then true all checkboxes on table in a for loop               // and set the all selected checkbox length in selectedCount attribute.             // if value is false then make all checkboxes false in else part with play for loop              // and select count as 0              if (selectedHeaderCheck == true) {                 for (var i = 0; i < getAllId.length; i++) {                     component.find("boxPack")[i].set("v.value", true);                     component.set("v.selectedCount", getAllId.length);                 }             } else {                 for (var i = 0; i < getAllId.length; i++) {                     component.find("boxPack")[i].set("v.value", false);                     component.set("v.selectedCount", 0);                 }             }          }        },


Two different definitions of Jordan canonical form

I am currently reading two linear algebra books. One is Hoffman/Kunze's and the other one is Friedberg/Insel/Spence's.  They define Jordan canonical form of linear operator in different ways.  In Hoffman's book, Jordan forms are obtained by the primary decomposition and cyclic decomposition. In this case, 1's can appear some sub-diagonal entries. For example,  $M = \begin{array}{cc} 2 & 0 & 0 & 0 & 0 \\ 1 & 2 & 0 & 0 & 0 \\ 0 & 0 & 3 & 0 & 0 \\ 0 & 0 & 1 & 3 & 0 \\ 0 & 0 & 0 & 0 & 3 \\ \end{array}$  But in Friedberg's (And almost any other linear algebra books for engineers..), 1's can appear some super-diagonal entries. For example,  $M' = \begin{array}{cc} 2 & 1 & 0 & 0 & 0 \\ 0 & 2 & 0 & 0 & 0 \\ 0 & 0 & 3 & 1 & 0 \\ 0 & 0 & 0 & 3 & 0 \\ 0 & 0 & 0 & 0 & 3 \\ \end{array}$  Can someone explain why they define differently and relation of each other?


When setting up a new SQL Server, I use the following code to determine a good starting point for the MAXDOP setting:  /*     This will recommend a MAXDOP setting appropriate for your machine's NUMA memory    configuration.  You will need to evaluate this setting in a non-production     environment before moving it to production.     MAXDOP can be configured using:      EXEC sp_configure 'max degree of parallelism',X;    RECONFIGURE     If this instance is hosting a Sharepoint database, you MUST specify MAXDOP=1     (URL wrapped for readability)    http://blogs.msdn.com/b/rcormier/archive/2012/10/25/    you-shall-configure-your-maxdop-when-using-sharepoint-2013.aspx     Biztalk (all versions, including 2010):     MAXDOP = 1 is only required on the BizTalk Message Box    database server(s), and must not be changed; all other servers hosting other     BizTalk Server databases may return this value to 0 if set.    http://support.microsoft.com/kb/899000 */   DECLARE @CoreCount int; DECLARE @NumaNodes int;  SET @CoreCount = (SELECT i.cpu_count from sys.dm_os_sys_info i); SET @NumaNodes = (     SELECT MAX(c.memory_node_id) + 1      FROM sys.dm_os_memory_clerks c      WHERE memory_node_id < 64     );  IF @CoreCount > 4 /* If less than 5 cores, don't bother. */ BEGIN     DECLARE @MaxDOP int;      /* 3/4 of Total Cores in Machine */     SET @MaxDOP = @CoreCount * 0.75;       /* if @MaxDOP is greater than the per NUMA node        Core Count, set @MaxDOP = per NUMA node core count     */     IF @MaxDOP > (@CoreCount / @NumaNodes)          SET @MaxDOP = (@CoreCount / @NumaNodes) * 0.75;      /*         Reduce @MaxDOP to an even number      */     SET @MaxDOP = @MaxDOP - (@MaxDOP % 2);      /* Cap MAXDOP at 8, according to Microsoft */     IF @MaxDOP > 8 SET @MaxDOP = 8;      PRINT 'Suggested MAXDOP = ' + CAST(@MaxDOP as varchar(max)); END ELSE BEGIN     PRINT 'Suggested MAXDOP = 0 since you have less than 4 cores total.';     PRINT 'This is the default setting, you likely do not need to do';     PRINT 'anything.'; END   I realize this is a bit subjective, and can vary based on many things; however I'm attempting to create a tight catch-all piece of code to use as a starting point for a new server.  Does anyone have any input on this code?


How can I add a page (pdf) that takes the size of an A4 page in a document?

How can I add a page that takes the size of an A4 page in a document? I use the package \usepackage[left=2.5cm,top=3cm,right=2.5cm,bottom=3cm,bindingoffset=0.5cm]{geometry}. I tried to add it that way \documentclass[14pt,twoside]{extreport} \renewcommand{\baselinestretch}{1.4} \usepackage[english]{babel} \usepackage[utf8]{inputenc} \usepackage{graphicx} \usepackage{color} \usepackage{float} \usepackage{amsfonts} \usepackage{amsthm} \usepackage{amsmath} \usepackage{enumerate} \usepackage{refstyle} \graphicspath{ {images/} } \usepackage[left=2.5cm,top=3cm,right=2.5cm,bottom=3cm,bindingoffset=0.5cm]{geometry} \usepackage{fancyhdr} \pagestyle{fancy} \fancyhead{} \fancyhead{} \fancyhead[RO,LE]{\footnotesize \nouppercase{\leftmark}} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{document} \begin{figure}[H] \centering \includegraphics[scale=1]{image} \end{figure} \thispagestyle{empty} \chapter{chapter one} \section{text} \chapter{chapter two} \section{text} \end{document}  But the way failed in the image (extension pdf) move to the second page when zoomed. It is not A4 size. The following images illustrate    The image should be on the front page of A4 size and there are no margins. Please help, thank you anyway.


A set is infinite iff it is equivalent to a proper subset of itself

A certain section of the chapter "The Axiom of Choice" on "Naive Set Theory" got me confused:     "[...] The assertion is that a set is infinite if and only if it is equivalent to a proper subset of itself. The "if" we already know; it says merely that a finite set cannot be equivalent to a proper subset. To prove the "only if," suppose that $X$ is infinite, and let $v$ be a one-to-one correspondence from $\omega$ into $X$. If $x$ is in the range of $v$, say $x=v(n)$, write $h(x)=v(n^{+})$; if $x$ is not in the range of $v$, write $h(x)=x$. It is easy to verify that $h$ is a one-to-one correspondence from $X$ into itself. Since the range of $h$ is a proper subset of $X$ (it does not contain $v(0)$), the proof of the corollary is complete. The assertion of the corollary was used by Dedekind as the very definition of infinity."   (The corollary would follow from "every infinite set has a subset equivalent to $\omega$".)  The question is: how can $h$ be a one-to-one correspondence from $X$ into itself if its range does not contain an element (namely, $v(0)$) that is in $X$?


A new Stack Overflow user recently asked how he could improve a question that was not well received:   I told the user to click Close(3) to see why the community was not receiving the question well. @psubsee2003 corrected me with:     The OP doesn't have 250 rep, so can't see the "Close(3)" link   I think that's a bad strategy. The close reasons are important feedback for a user, and I'm having trouble understanding why the feedback would be with held from them.  The current strategy of denying feedback and allowing the question to whither and die does not seem like a good one. It clutters the site with poor questions, it does not reinforce user training of site features, it causes the creation of duplicate questions that don't materially improve, and it creates a poor user experience.  In fact, the cited question is an example of creation of duplicate questions that don't materially improve. The poster originally asked a similar question that was closed too.  And, here's another one that would have benefitted from a user learning what was going on:        Notice they do not suffer the "false, misleading or fictitious reason" as argued by some others below.  Request: Please allow new users to view close reasons on their questions.    Related to withholding close reasons, a custom off-topic close message is displayed immediately. So immediately providing feedback has a precedent. (You can see an example of the immediate feedback on countless questions, like ).  If withholding information is the strategy, then it seems to me the custom close message should be with held too.    Related: . But the request in this question is less encompassing than the related question.


The inconsistent long i sound in English

As a phonics teacher, I have long had a problem with finding the right explanation to my students about an inconsistent sound. Hope someone has the explanation to it here.   The long i sound in English represented by the IPA: aɪ exists in a lot of words including lie, by, tie, night, rice, lice, etc. Here comes the problem.   Not even talking about accents of different regions, but even within the same person, there seems to be an inconsistency. For example, when one says lice, he/she doesn' say lie-s, but with the vowel being something different. It also applies to tie vs tight, bye vs bite, fly vs flight, and many more. I wonder whether other phonics teachers point this out to their students and, if they do, how they explain it? Is there a rule to when the long i is one way and when the other? Or is it really  the same but it's my ears that's playing tricks on me? Appreciate any help and discussions.


How can I change the size of Unity 2D launcher icons?

Is it possible to make Unity 2D launcher icons smaller or larger than the default size?


What's the connection between Kendall tau and AUC ROC?

What is the relationship between Kendall tau and the area under the receiver operating characteristic curve (AUC ROC)?


What does "the denominator does not contain any theta dependence" mean in Bayes' Rule?

Every lecture and book says that the denominator in Bayes' Rule does not depend on the parameter $\theta$. However, the denominator also includes $\theta$ in the formula of Bayes' Rule. I just cannot understand what it really says.


Desoldering/soldering 1/4" chip with eight pins

I need to transfer a working eight-pin 1/4" (4 mm) chip from the top PCB to the bottom PCB that has a non-working chip. Is there a special soldering tool for such micro soldering? Has anyone tried desoldering/soldering something this small?   Any special technique for this or can it only be done by machine?


What's the different between the solutions

I have 2 solutions (see image below). This is how I create them:   File -> New -> Project -> ASP.NET Web Application File -> New -> Web Site -> ASP.NET Web Site     What's the different between the projects?  In Solution Explorer the only difference is the icon next to the project. They have the same file structure.  The question came up due to a problem I had with 2 solutions ()


I found that with long.Parse, ToString can take argument and I can format it to desired string, for example.  Input:     Console.WriteLine(long.Parse("123").ToString("#-#-#"));  Output: 1-2-3   I wanted to do something similar with string, lets say I wanna parse string to format ####-###-####. Is there any way to do it without regex with one liner like example above?  EDIT  Ok, so I may be misunderstood, I didn't want to parse numbers, but string instead. I can do in python like:  '{}-{}-{}'.format(*'abc') and I will receive a-b-c. In C# it seems to work only with numbers.


Why does latex put the images at the end of the PDF file?

This is really interesting. In any editor or formatting language I ever used images and text would appear in the order in which you have entered them. Not so much in LaTeX. I have a following figure:  Blah blah blah:  \begin{figure}[htb]   \centering   \includegraphics[scale=0.8]{image.eps}   \caption{this is image} \end{figure} blah blag. Blah.   These are in the document headers:  \usepackage{graphicx} \usepackage{grffile}  \usepackage[outdir=./]{epstopdf}   And the image jumps to the end of the end of my PDF, leaving the text like this:     Blah blah blah:    blah blag. Blah.   Which looks stupid. The image looks stupid too, so alone at the end:     Why does LaTeX do this and in which cases it's a good thing? How to prevent it when it's not a good thing?


I set my displays to sleep with xset dpms force off after locking the screen with kscreenlock. This is great, the displays wake up when the mouse is moved (by me, air, the cat). I'd like to set it in a way that only the keyboards can wake up the screens again.  Is there some way to do this for the KDE screen locker or in general?


Is there a way to prevent a file or folder being set invisible ? I am working on an infected machine (which I cannot disinfect) that constantly makes the files and folders in my usb stick invisible. I use the:  attrib -h -r -s /s /d f:\*.*  command to make them visible again but the problem continues since this command just saves the day.


Reserve Space for Topbar Ads as the page loads

Currently, if you have ads enabled on any Stack site that offers ads, the topbar ads are loaded in after the site itself is loaded. Instead of reserving sufficient space for that when the site is loaded, everything on the site just moves downwards as the ad loads in.  It would be significantly less obnoxious and significantly more user friendly if you reserved the space for the ad before loading it in, right when the site itself loads, so things like flag or edit buttons or vote buttons don't suddenly jump downwards as the ad loads in.


Resample raster image, how to choose new resolution?

I know this is not a new question, and I know it depends on the context and what I would like to do with the data, but I am still finding it difficult to solve this problem in practice. And I haven't found any good answer online (this question was marked as possible duplicate, but I do not think this is the case, so I have modified my question, I hope it is clearer now).  For example: I have a  of modeled atmospheric N deposition for the whole world, with a resolution of 5 by 3.75 degrees. Now I would like to resample it to a finer resolution, say with cubic resampling from GDAL warp.     EDIT:  The reason I want to do this is that I would like to estimate N deposition per country. I understand I am introducing an error when I do any resampling, however as you can see in the image, the pixels are really quite large compared to the size of an average country.  Now I could run a zonal statistics on a world countries vector layer, using this raster image as it is. However, I suspect that my results would be of better quality if I resample the raster image first, to a higher resolution. If I am wrong, than please let me know and I will close this question myself.  Question: Can you please explain what logical steps and reasoning I should follow to decide the new resolution of the raster image? The aim here is to then run a Zonal Statistics on the higher resolution raster image, with a vector layer containing country boundaries.  I would like this to be an example of how to make such a decision, I don't care so much about the answer to this specific case.


get list of objects distinct by all fields

How can I get all the distinct objects in a list using java 8 streams? It has to compare all the fields of objects with each other. For example   Person a = Person("nameA", "35") and  Person b = Person("nameA", "35")   should be equal.  What I've attempted   personList.stream().distinct().collect(Collectors.toList()) is returning a list of 2 persons, instead of only 1.


Why did Thor choose Earth after forging Stormbreaker?

In Avengers: Infinity War, why didn't Thor choose to go to Titan right after the forging of Stormbreaker?  What prompted him to go to Earth instead?


I've been looking at the python code loging of Blender. But in there things get loged as mouse clicks.  What i like to do is combine a few images into a larger one using compositor, but i need control over compositor by python script. The problem seams to me that it is a bit hard to "spawn" a few nodes, set their values and connect them.  I need an micture of:  image, scale, source image location, mix nodes, output nodes  I have no Code samples other then the log of blender python which in this case is of no big help.


Shouldn't it be impossible to fall into a black hole?

Imagine that you, unfortunately, fell into a black hole. For external observers, you would slowly go closer and closer to the event horizon. Then, when you reach the event horizon, you would appear to be frozen there and get red-shifted for an external viewer.  Since it takes infinite amount of time to enter the event horizon, which will happen instantly for you. It is possible that by the time you enter, the black hole, or maybe even the universe, has ceased to exist. So, how would you enter it if it doesn't even exist anymore?


Is it a problem if I have a flag that's been pending for over a day?

So, I flagged  for being off-topic, and the flag has been pending for 2 days. Why? Here's a relevant screenshot.


A Combinatorics Problem Involving Some Badminton Players

In a badminton competition there are n players. All the players play with each other exactly once and each game has a result, i.e. win or lose. No tie is permitted. Now all the players enlist the name of some other players in the following manner -  1. He enlists the name of all the players he defeated. 2. He enlists the names of the players who are defeated by the players whom he defeated. For instance, a player A enlists the names of B and C if A defeats B and B defeats C.  Prove that there exists at least  one such player A who has enlisted the names of all the other players.


The $f(x)=\sqrt{x}$ has a domain of $[0,\infty)$. As of in our textbook it is written that range is also $[0,\infty)$. How? $\sqrt{x}=-\sqrt x\space or \space \sqrt x.$ According to me range should be $(-\infty, \infty)$ then. for example:  f(1) = -1 or 1 f(4) = -2 or 2 f(9) = -3 or 3 . . . $f(\infty)=-\infty \space or \space \infty$


How do file permissions work for the "root" user?

I have the following file:  ---------- 1 Steve Steve 341 2017-12-21 01:51 myFile.txt   I switched the user to root in the terminal, and I have noticed the following behaviors:   I can read this file and write to it. I can't execute this file. If I set the x bit in the user permissions (---x------) or the group permissions (------x---) or the others permissions (---------x) of the file, then I would be able to execute this file.   Can anyone explain to me or point me to a tutorial that explains all of the rules that apply when the root user is dealing with files and directories?


Does constructing huge buildings affect the rotation of the Earth, similar to skater whose angular rotation increases when her arms are closed comparatively than open?


I use 3 languages when I brows the internet and changing it from the top panel is quite disturbing on windows you can changed the languages with pressing alt+shift so can I some how do the same on ubuntu   thank you in advanced


I'm writing a VBA module that uses a lot of computational power. To speed things up, I'm using all available processors on my machine. Excel gives me an option though to use a different number of threads. Is there a difference between (for example) specifying 8 processors versus selecting 8 threads? Would selecting 7 threads limit the machine to using 7 processors?  Thank you


Badge image inconsistent when on profile view

I have recently realized that when visiting an account page then scrolling down to other accounts, the badges will look as if they were all from the current site.   IE: The photo above was taken from my bag on Arquad site and represents this bug. All badges are represented as coins rather than the look of their own sites. '  I am not 100% sure this is what the engineers of StackExchange are looking for so I am just pointing it out.  Thanks.


Can anyone tell me what this command means?  I've seen it in a tutorial but can't get it well. find . -type f | xargs file


Automatic base URL not picking up https://

My Drupal site is using https:// but the base URL is not using it.  My site therefore is not opening properly. Is there any way to make Drupal pick up the correct base URL?  I tried adding $base_url in settings.php but it's giving me this error:     GET  404 (Not Found)


Photolysis in the Light Reactions of Photosynthesis

I'm a bit confused concerning photolysis. During the light reactions, photons are used to excite the chlorophyll molecules so they are passed to the primary electron acceptor. The electrons initially come from a split water molecule. Is water split by the photons?


How does the system select questions in the newsletter?

In , we know that there are 3 sections in weekly newsletter and they are all automatically selected by the Stack Exchange system. How does the system select questions?


Its/It's for "It", but not for other words?

Why is there a distinction between "it's" and "its"?  You can write "The cat's walking." where "cat's" might ambiguously be either "cat is" or "cat (possessive)", and I don't think anyone considers this to be a major problem of usage. What's different with its/it's?  Perhaps it is better to compare with other pronouns.  Its is substantially different in form than other genitive pronouns, in that it appears to be a relatively modern construction (OED has the earliest attested use in the 15th century) which in fact generalizes from the apostrophe possessive, or is a result of the same transformation that produced the apostrophe from OE strong|singular|masc./neut. -es. "Him"->"his" definitely isn't generalized from a widely attested grammatical rule; they've been in the language from old english essentially unchanged. By the logic that "its" operates similarly to other pronouns one would expect its (its' ?) modern form to be something like "his" which was its' original genitive form.  So my question is, who decided that its doesn't get an apostrophe, and why?


Translating a good question from a foreign language: do it and how?

I remarked this problem from this post:    Lets say I see a really good question in a foreign language and I am fluent in this language.  I want to translate it in English so all users can understand it.  If I do that, we have following occuring problems:   Source: To guarantee that the translation is correct, the original text should be preserved and visible (at first ?) so that other people can verify that this is a correct translation. Grace period: If we would allow someone to translate questions, we need a grace period. If these questions are open, there is a very high probability that the question will be closed and removed -> useless work done. We would only need a few hours. Mark as translation in progress: To prevent flagging and complaints it should be possible to mark this question so that people see that a translation is in work.   If you support the idea that people may translate questions, is it possible to introduce documentation rules, grace period and translation mark into Stackoverflow ?


I can't snap 2d cursor to vertex in UV editor in blender 2.8

I'm in UV Editor and trying to snap the 2d cursor to the vertex ( while the vertices are visible). I turn ON snap and set it to 'vertex mode' , but the 2d cursor won't snap to any visible vertex at all. I can only make it snap to the grid (increment node). Is it a bug ? or did i miss something here ? i'm using 2.8.


Why is it (is it?) important to make it hard for banned users to check their deleted posts for 6 months (as opposed to 60 days)?

To avoid misunderstanding, I am not really opposed to making life harder for banned users in general. Here I am only trying to figure reasons of making so in one particular case and in certain particular way (frankly, if there are such reasons this would probably make me feel better).  Banned users are allowed to post :     If you're unable to improve your existing questions, you'll get the chance to ask one new one 6 months after your last question.   This can become complicated if they have deleted posts affecting the ban.  If these deleted posts are older than  it becomes quite difficult for user to find and check these and decide whether to wait for next attempt or maybe try to improve these deleted posts or maybe  (especially if they could see that time remaining for next attempt is long enough to justify investing effort in improving prior posts).  I think above can be made easier for them if the system changes the limit of showing deleted posts from 60 days to 6 months.    My understanding is, above change would be very low effort technically, kind of changing particular config parameter and editing few docs referring it in a non-parameterized way. Also it seems to be low risk because it's easy to revert if it turns out that it causes too much trouble.  So, the only reason I could imagine for keeping the current way is that it should be somehow important to make it hard for banned users to check their deleted posts for 6 months instead of current 60 days. I would like to understand the reasons why this is (is it?) important.  (Or maybe changing the parameter of showing deleted posts is indeed technically harder than I assume? To address particular , change is supposed to be done in a most technically straightforward way, that is for all users, and not only for .)


Do you need to get a new ESTA when your passport is renewed?

A bit over a year ago I applied for (and got) an ESTA for travel to the USA, valid for two years. That validity takes the ESTA to pretty close to the end of the passport validity.  I've just renewed my passport a bit early, to avoid problems with having enough passport validity on a different trip. Do I need to also get a new ESTA (for another 2 years starting today), or can I continue to travel on the existing ESTA until that expires, and only need to renew it then? (I am planning to travel to the US before the old ESTA expires)  (If you wish to travel to the US under the Visa Waiver Program, except by land, you need to to apply for an ESTA (Electronic System for Travel Authorization) before you travel.)


Find the greatest value of $a^2\cdot b^3$ where $a+b=10$

Find the greatest value of $a^2\cdot b^3$ where $a,b$ are positive real numbers satisfying $a+b=10$. Determine the values of $a,b$ for which the greatest value is attained.  At first I tried to find the value by putting $a=10-b$, I found a expression, but I got not way to do anything.   If we apply A.M-G.M. inequality, I think we found the minimum value or something else. It is a pre-Olympiad level problem. So I need some answers or some good hints.


I am playing Skyrim. My two kids won't move to my new house in Riften. Before, the game gave me the option to tell them that it was time to move, but as soon as I bought the house it doesn't have that option anymore...?


Does the improper integral $\int_0^\infty |\sin (x^2)| \; dx$ converge?

I have seen many questions about almost the same integral; the only difference is the absolute value. How can I check if this integral converges (as real integral)?  $\displaystyle\int_0^\infty |\sin (x^2)| \; dx$  EDIT: I've read  in topic you linked, and I don't fully understand the steps in:     Now we observe that $|\frac{\cos(x)}{2 \sqrt x}|\geq \frac{\cos^2(x)}{2 \sqrt x}=\frac{1}{4\sqrt x}+\frac{\cos(2x)}{4\sqrt x}$.    And this, which arguments?      By the same arguments above $\displaystyle\int_{0}^{\infty}\frac{\cos(2x)}{4\sqrt x}dx$ converges.


single thread locking to build resource and later the remaining threads can access the resource C#

best way in c# to make only one thread to build the resource so that the remaining threads can wait and then later access the resource.  I have a dictionary which needs to be build by a thread for the remain threads to use.  private Dictionary<string, List<A>> _aDictionary;   I have a method which gets or creates the dictionary.  public async Task<List<A>> GetAs(string aId) {      if (string.IsNullOrWhiteSpace(aId))      {          return default;      }      try      {           if (!_isCached)           {               await lockSem.WaitAsync();               if (!_isCached)               {                   await build(); // builds the dictionary                   _isCached = true;                   lockSem.Release();               }            }           return _aDictionary.TryGetValue(aId, out var a) ? a: default;       }       catch(Exception ex)       {           _logger.Error("Error", ex);           lockSem.Dispose();           return default;       }   }   Others should not access this resource until the _isCached is set. So I looking for suggestions or best practices in this scenario


$a^2+ab+b^2=1$, how many ordered integer solutions exist?

I found the answers to be a=-1, b=0; a=1,b=0; a=0,b=1 and a=0,b=-1. Only 4 pairs, however the answer is 6. Please tell me how to proceed.


How to install Windows on GPT disk without UEFI BIOS?

My PC does not support UEFI BIOS, but it has Legacy BIOS. The motherboard is "P5LD2-X1333".  I need to install Windows 8 on the 3TB hard drive with GPT scheme, since as we know, the MBR scheme does not support more than 2TB space. Also, you can not boot OS from a GPT hard drive without UEFI BIOS.  So how can I use the hard drive with 3TB space with OS and without UEFI BIOS?


More compact Algorithm template in Latex

All,  I am using the following Algorithm template:      \usepackage{algorithmicx}     \usepackage[ruled]{algorithm}     \usepackage{algpseudocode}  \vspace{-0.2cm}% \alglanguage{pseudocode} \begin{algorithm}[h] \small \caption{Delete item from Hash Table (with mCBF and aCBF)} \label{Algorithm:delete_mCBF_aCBF} \begin{algorithmic}[1] \Procedure{$\mathbf{DeleteItem}$}{item $x$}     \LineComment{\emph{Quick check if $x$ is in mCBF}}     \For {$i = 1 \to k$}             \If {$mCBF.C_{f_i(x)\%N}$ == 0}                 \State \textbf{return}             \EndIf     \EndFor     \LineComment{\emph{Look up $x$ in $aCBF_1\cdot\cdot\cdot aCBF_k$}}     \For {$i = 1 \to k$}         \If {\textbf{CBF\_query}($aCBF_i$, $x$) == \textbf{TRUE}}             \State $j \gets C_{f_i(x)\%N}$             \For {item $y \in B_j$}                 \If {$y.key == x$}                     \Comment \emph{found}                     \State \emph{remove $y$ from hash table}                 \EndIf             \EndFor         \EndIf     \EndFor \EndProcedure \Statex \end{algorithmic}   \vspace{-0.4cm}% \end{algorithm}   And I get this:    However, there are too many lines of end if and end for. Is there any more compact Algorithm template that does not contain these lines?


Sorting integer field in ArcGIS Modelbuilder and using smallest value as variable for tool?

I have to populate a new field using a formula containing the smallest value of an existing field.   As this is a small part of a larger model I am wondering which is the most efficient method.   My thoughts are as follows:   Sort the field ascending and somehow use the top value or Use a formula to search for the smallest integer greater than zero and use this value as a variable?   Which method would be most viable with ModelBuilder from ArcGIS 10.3.1 for Desktop?


Can't install VLC package from the PPA "The following signatures couldn't be verified because the public key is not available"

Since I installed Ubuntu I was unable to install video Codecs I get the following errors: The following packages have unmet dependencies:          The following packages have unmet dependencies:      gstreamer1.0-libav: Depends: libavcodec-extra-54 (>= 6:9.13) but 7:1.2.5-1~trusty1 is to be installed                         Depends: libavformat54 (>= 6:9.1-1) but 7:1.2.5-1~trusty1 is to be installed                         Depends: libavutil52 (>= 6:9.1-1) but 7:1.2.5-1~trusty1 is to be installed                         Depends: libc6 (>= 2.14) but 2.19-0ubuntu6 is to be installed                         Depends: libglib2.0-0 (>= 2.37.3) but 2.40.0-2 is to be installed     gstreamer1.0-libav:i386: Depends: libavcodec-extra-54 (>= 6:9.13) but 7:1.2.5-1~trusty1 is to be installed                              Depends: libavformat54 (>= 6:9.1-1) but 7:1.2.5-1~trusty1 is to be installed                              Depends: libavutil52 (>= 6:9.1-1) but 7:1.2.5-1~trusty1 is to be installed                              Depends: libc6 (>= 2.7) but 2.19-0ubuntu6 is to be installed                              Depends: libglib2.0-0 (>= 2.37.3) but 2.40.0-2 is to be installed   However, I was using VLC. I had to uninstall VLC for a reason, now I'm unable to reinstall it. When I try to install VLC it gives me the following errors:  The following packages have unmet dependencies:  vlc : Depends: vlc-nox (= 2.1.4-0ubuntu14.04.1) but it is not going to be installed        Recommends: vlc-plugin-notify (= 2.1.4-0ubuntu14.04.1) but it is not going to be installed        Recommends: vlc-plugin-pulse (= 2.1.4-0ubuntu14.04.1) but it is not going to be installed E: Unable to correct problems, you have held broken packages.   I've tried all the solve for this kind of problems, none of the worked for me. I've also tried aptitude which also didn't worked. Installation from source also failed.   apt-get update gives me an error:  W: GPG error: http://ppa.launchpad.net trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 6A9653F936FD5529


Time period of a pendulum when a constant horizontal force acts

The time period of a pendulum is given by $$T=2\pi\sqrt{\frac{l}{g}}$$  Will the time period change if a constant horizontal force acts on the pendulum? For example, if a force $F$ acts on the Bob along the horizontal. Or applying an electric field  along the horizontal and giving the Bob a charge.  I think the time period won't change but the equilibrium position will change. The only restoring force is gravity. I tried to prove it:  For small displacement of $\theta$ about point of suspension, the torque about the point of suspension is $$\tau=F\cos\theta\cdot l - mg\sin\theta\cdot l$$ $$I\alpha=F\cos\theta\cdot l - mg\sin\theta\cdot l$$ For small angular displacement, $\sin\theta=\theta$ $$I\alpha=F\cos\theta\cdot l - mg\theta\cdot l$$ For SHM, $\alpha$ should be proportional to $\theta$. The only term that obeys the SHM rule is $mgl\theta$.


Android Studio: Locale.getDefault().getLanguage() not working

I am programming a small app with a multi language feature.  But when I'm going to check the default language, it wont work. Does anyone know why?  Code:  String Lang = Locale.getDefault().getLanguage();     if(Lang == "de") {         Log.i("de", "de");     }     else if(Lang == "fr") {         Log.i("fr", "fr");     }     else {         Log.i("en", "en");     }


The study found relatively consistent benefits [for/of /to] using the drugs in severely ill patients.


How do you launch Windows Terminal from the "WinKey+r" run command in Window 10?

I installed the cool Windows Terminal from the Microsoft Store but I tire of clicking from the Windows Start menu to get to it. It is well known that you may more simply key "WindowsKey+r" and there enter "cmd" to launch and enter a persistent command line terminal. What is the command, however, to launch Windows Terminal, per se, in lieu of the long-time standby "cmd" or even "pwsh"?


So I've got some problems while downloading Ubuntu.  As I clicked on the downloadlink ( the first one you see when you get on the destkop page), the Ubuntu link started downloading.  When it was downloaded the problems started because I don't know which further stap I need to take since the download program mentions things like DVD and I didn't get a DVD from Ubuntu I just got the downloaded software!  Which steps do you need to take after you've downloaded Ubuntu?     What do I need to do when I dowloaded the software?  Can anyone explain it in steps ?


I am recently working on a template linked list, however I have encounered a problem      #ifndef _T_NODE_ #define _T_NODE_ using namespace std;  template<typename T> class TNode{ public:     TNode();     TNode(T a);      ~TNode();  private:     T template_;     TNode<T> *link_; };  #endif   My implementation is:  template<typename T> TNode<T>::TNode(){     link_ = NULL;     template_ = T(); }  template<typename T> TNode<T>::TNode(T a){     template_=a;     link_ = NULL; }  template<typename T> TNode<T>::~TNode(){     delete link_; }   In another Class, I tried to referred it in a function as such:  TNode<Bike> * actPtr;         actPtr = new TNode<Bike>(a);   I receive the following error:  error LNK2019: unresolved external symbol "public: __thiscall TNode<class Bike>::TNode<class Bike>(class Bike)"  referenced in function "public: void __thiscall


GIF/SWF animation embedded in LaTeX document (PDF)

There seem to be plenty of resources for how to do it (even on this website), but I'm struggling with the process.   Can someone provide a link to an example pdf with the working animations in it? The only I see have buttons and are interactive (but aren't working on my machine anyway)-- what I would like is even simpler, just a looping gif file that never stops (I'm trying to show the evolution of a system, against certain parameters and time).   Thanks for any examples.


An application of the intermediate value theorem

Show that between any two real solutions of $e^x \sin x = 1 $, there is at least one real solution of $e^x \cos x = -1 $ Try: Let $f(x) = e^x \sin x - 1 $. Consider $I = [0, \pi/2]$, Then, $f( 0) = -1 $ and $f( \pi/2) = e^{\pi/2} - 1 >0 $. Thus, one can find a solution $c_1 \in I $ such that $f(c_1) = 0$. Similarly, if $J= [ \pi/2, \pi ] $, one can find $c_2 \in J$ such that $f(c_2) = 0 $. Consider the interval $[c_1,c_2]$. Let $F(x) = e^x \cos x + 1 $. We have $$F(c_1 ) = e^{c_1} \cos (c_1) + 1 < e^{c_1} \cos 0 +1 =  e^{c_1} + 1 >0 $$ and $$ F(c_2) = e^{c_2} \cos (c_2) - 1 < e^{c_2} \cos \pi - 1 = - e^{c_2} - 1 < 0 $$ so, $\mathbf{there \; exists}$ some $\alpha \in [c_1,c_2]$ such that $F(\alpha) = 0$ as we wanted to prove. Is this a correct proof?


blender is amazing i have to say to begin with!!! but some of the ux design is like whaaaaatt:)  so once again my interface got messed up and i cant get it to how it was before..  how can i get rid of all the tabs/windows/duplicates there is no "close" option anywhere no matter where or how i click. (well i have to admit i didnt try every possible pixel on the screen)  can blender pleeeeeease add standard/recogniceable buttons for moving these tabs around/closing them?  thanks!


Adding Multiple IPs to One Network Interface

I've read several articles and tried various methods and I'm pulling my hair out... I know the answer is punching me in the nose but I just cant seem to see it.  I have 2 network ports on my server (Debian LAMP): eno1 eno2  I have a block of 5 IP addresses and I'm trying to assign the extra IPs to eno2 (or eno1, I don't care).  I have read the debian wiki and tried!  I added netmask field however dont believe it has to be there per debian wiki.  I got all IPs to ping successfully the other night with listing as(no alias #): Iface eno2 inet static Address ..***.*01  Iface eno2 inet static Address ..***.*02  Etc.. But then the following morning ALL interfaces were down and had to do a hard reboot which brought eno1 back online (though the "aliases" did not work after that, only the first IP set for the interface was reachable on both eno1 and eno2)  I've also tried using aliases: iface eno2:1 inet static address ...  I am using tabs properly (I believe) for the address field as i read in a similar article that spaces wont work properly on network config.  What am I doing wrong? Or may be I'm misunderstanding an answer in a relevant article.  I appreciate any information provided. If all else fails I will just use a single ip for eno1 and another single ip for eno2. I'm scared to do any changes under /dev/network (if I recall correctly) because I'll cost myself another 1hour drive to my server.  Guessing in the wind: Interface aliases MAC addresses are posing an issue? May be make each interface alias with their own MAC? If so, what is a good method for making MAC addresses?  Final piece I'll add: I thought I had this configured correctly because if I run ifdown eno2 && ifup eno2 it would bring network interface back online. Some variations of the file would fail when running that command... so I feel like in all over the answer but again I feel I'm missing a very small detail.  Debian 9 w/ Apache


If $W\subset V$ is a subspace such that $T(W)\subset W$, then $V/W$ is finite dimensiona

Let $V$ denote the vector space of polynomials in one variable with coefficients in $\mathbb{R}$, and let $T(f(x))=x(f(x))$.     Prove that if $W\subset V$ is a subspace $\neq 0$ such that $T(W)\subset W$, then $V/W$ is finite dimensional.   My attempt: We know that $\forall p\in W$, $xp\in W$ because $T(W)\subset W$, so given that $1$ is in our subspace $W$, so must $x$ be, and hence every linear combination of $x$ and coefficients in $\mathbb{R}$. Thus, $V/W$ is simply the constant functions (is this true?)  It this is the case, how do I show the constant functions are finite dimensional?  I understand this may have been solved before, but I would like insight on whether my line of reasoning works.  Any help appreciated!


Mechanism for a photon to impart momentum to an atom

Picture a simple hydrogen atom with one electron which is bound to a proton (nucleus). When trying to impart momentum to the atom, we may specify the photon wavelength to be $\lambda = 121.57$ nm to access the 1s-2s electronic transition. But in this picture, where exactly does the photon's momentum go and how does it get there?   We know that the electron can only occupy quantized states and the transition is instantaneous. The photon energy has decreased the electric potential energy between the proton-electron pair by $hc/\lambda$. But do not the quantized orbits occupied by electrons have well-defined momentum, too? Since the electron's momentum now that it has gone from 1s to 2s may not necessarily be the photon's total original momentum, $h/\lambda$, where does the rest of this momentum go? And is this momentum transfer an instantaneous process as well?   I believe a partial answer is that the entire atom has momentum imparted to it, but what is the mechanism to make the nucleus start moving if the photon was wholly absorbed by just the electron and the electron cannot simply drift off its quantized orbit (which would then pull on the nucleus via Coulomb interaction)? Perhaps answering this question may help elucidate the above: is imparting momentum by photons with wavelengths corresponding to particular transitions more efficient than photons with arbitrary wavelength?


Showing that ridge regression is a solution to the following optimization problem

$$\hat{\theta}=\arg\min_{\theta}\{ ||y-X\theta||_2^2+\lambda||\theta||_2^2\},$$ where $X$ is an $n\times p$ matrix.    We have if $y=X\theta+\varepsilon$ then $$\hat{\theta}^{\text{ridge}}=(X^TX+\lambda I)^{-1}X^Ty$$ So I'm kinda confused, because if $y=X\theta+\varepsilon$, then $||y-X\theta||_2^2+\lambda||\theta||_2^2=||\varepsilon||_2^2+\lambda||\theta||_2^2.$ But I'm confused as to how to show that  $$(X^TX+\lambda I)^{-1}X^Ty=\arg\min_{\theta}\{ ||y-X\theta||_2^2+\lambda||\theta||_2^2\}.$$ Any help would be much appreciated. Thank you. I gotta edit this cause someone said it's a duplicate of an entirely different problem cool.


Looking at the content of a character device's file

Why is it possible to look at the contents of a block device's file like /dev/sda using cat or a hex editor? Why can I not do the same for a character device like /dev/pts/3?


Visit to Paris in layover time, which visa?

I have booked a flight from Delhi to Prague with layover at Paris for 12 hrs. Want to do sight seeing in Paris during layover period.   Do I have to apply Schengen Visa from French embassy or Czech embassy in India.


What's the difference between the environments quote and quotation?

On meta, I've found the disscussion , but it doesn't answer my question.  When should I use the environment quote? When quotation?


Changing the values of variables in methods, Java

I have a question about changing the values of variables in methods in Java.  This is my code:  public class Test {     public static void funk(int a, int[] b) {          b[0] = b[0] * 2;          a = b[0] + 5;     }       public static void main(String[] args) {         int bird = 10;         int[] tiger = {7};          Test.funk(bird, tiger);     } }   After the execution of the method Test.funk(bird, tiger), the value of bird is not changed - it remains with the value 10, even though in the funk() method we have changed the value with a = b[0] + 5;  On the other hand, the value of the element in the array changes, because we have the statement b[0] = b[0] * 2;  I don't understand why one thing changes and the other not? Could someone please explain this for me.


This is a similar to . However, the answer does not correct my problem.   I have a variable:  $font="font-family:Arial,\"Helvetica Neue\",Helvetica,sans-serif;";   I want $font to be INSERTED into mysql Database, but all that is inserted:  "font-family:Arial,"   I need the quotes inserted to recognize the data. How do I go about inserting all of the data?


Show that there is $z_0$ on the unit circle such that $|p(z_0)|>1$.

Let $p(z)=z^n+a_{n-1}z^{n-1}+\dots+a_0$.  Prove that if $p(z)\neq z^n$, then there is $z_0$ on the unit circle such that $|p(z_0)|>1$.  Hint: Consider $q(z)=z^np(1/z)$.  I have really been messing around with $q(z)$, I have considered the case when $|z|=1$ (since that would put $z$ on the unit circle.  I have done many other things, tried Triangle Inequality, Lower Triangle Inequality, etc.  I just can't seem to find the required clever step to solve this.  I am only looking for a hint, please, as this is a homework problem.  By hint, I mean a tad bit more of a hint than the one that is given in the problem.  Thanks


Python list .extend method breaks string into characters

I am reading two columns of values out of a .csv file a line at a time, which yields a list of row entries made up of two strings (something like ['cat1', 'dog1'])  When I iterate over all the rows I extracted I try to put all the "cats" in one list and "dogs" in another, kind of like this:  for row in csv_file_entries:     catlist.extend(row[0])     doglist.extend(row[1])   I expect doglist to be:   ['dog1', 'dog2', 'dog3', 'dog4', ..., dogN]  but instead I get   ['d', 'o', 'g', '1', ' ', 'c', 'a', 't', '1', ' ', ...] ETC  I suspect when I find out why the characters are the list elements instead of the strings I will also figure out why the cats and dogs are in the same list, even though the row elements 0 are dogs and row elements 1 are cats.  My actual code, with silly debug statements is below:  # get csv file containing digitized EOT data # first column is day of year, second is EOT minutes # taken from US Naval Obs site and digitized with web digitizer program fname = 'C:\\time_calculator\\EOT.csv' dtzd_DOY = dtzd_EOT = [] print("tarrtart", dtzd_DOY) with open(fname, 'rt') as csvfile:     eot_entries = csv.reader(csvfile, delimiter=',') #    print(eot_entries)     print("pooooty", dtzd_DOY, dtzd_EOT)     for row in eot_entries:         print(row, row[0], row[1])         thisDOY = row[0]         thisEOT = row[1]         print(thisDOY)         print(thisEOT) #        thisEOT = "heychittyfgfgfttrgrtfgrt"         dtzd_DOY.extend(thisDOY)         dtzd_EOT.extend(thisEOT) print(dtzd_DOY, dtzd_EOT)   This is my first question, so don't feel bad about correcting my form.


Why is $\cos(\arctan(3x)) = \frac{1}{\sqrt{1 + 9x^2}}$? I've tried messing around with identities but still I'm not sure what's going on here.  Thanks.


Would this be considered duplicate content for a multi-language site, and is it necessary to redirect by language?

Our company now has 2 domains linked to one FTP: site.lt and site.eu   In the .lt site, we show the content in the local language In the .eu site, we show foreign languages like site.eu/lv.   1). My first question is if pages like:  http://site.lt/oliver-weber-auskarai-symbol-9919  http://site.eu/lv/oliver-weber-auskarai-symbol-9919  will be considered duplicates by Google if they have:   Same title Same description Different language body Same body description   Currently in the <head> section we use alternate tags:  <link rel="alternate" hreflang="lt-LT" href="http://site.lt/oliver-weber-auskarai-symbol-9919" /> <link rel="alternate" hreflang="lv-LV" href="http://site.eu/lv/oliver-weber-auskarai-symbol-9919" />   and canonical links to default local language pages to avoid duplicate penalties:  <link rel="canonical" href="http://site.lt/oliver-weber-auskarai-symbol-9919"/>   But I think that canonical links will not let us get indexed with other languages with site.eu. Should we not use canonical links?  2). The second question is:  Is it necessary to redirect users/bots to languages by IP or HTTP language header? Can Google add a penalty for this? Or maybe this will be better?  I had read a lot of information and suggestions about these questions, but all them seem to be different.


How to deal with questions that might get more attention on Stack Overflow when more appropriate for another board

I was just reading  regarding the appropriate place to post questions about WAMP (XAMPP in my case, but the same question):    It seems to suggest the proper place to ask my XAMPP question would be Super User. Then I was curious if my question would get more exposure on Stack Overflow, so I looked up how many questions about XAMPP are on either site. There are 63,394 questions tagged 'XAMPP' on Stack Overflow, and only 1,357 questions on Super User. So there is apparently more activity for XAMPP questions on SO, so it would appear that the appropriate place to ask a XAMPP question is not where my question would get the most exposure.  As someone looking to find a solution to a problem as quickly as possible,  I would be inclined to ask the same question in both Stack Overflow, and Super User. That doesn't seem right to have to ask in both places.  LET ME BE ABSOLUTELY CLEAR THAT I AM NOT ADVOCATING FOR ANYONE TO POST A QUESTION IN TWO PLACES. I'm saying as a matter of (possibly) self preservation, in some cases — NOT necessarily my example — it might be or seem to be more likely to yield more results, and that INEVITABLY people will choose that option. And that I believe that is a fault in the system.  Is there any established way to handle this issue?  I looked at , but I think my question differs, in that I believe Stack Overflow would not be the appropriate place for my question, but I feel like I might put it there anyways, just to get a solution faster.  I'm no expert, but it seems to me like there should be a way to take any question, and be able to select and/or change which sites the question gets posted to. That way there would only need to be one question, and one place to edit or answer it.  I do not believe my question to be a duplicate of  as this issue was a bit of a side note, and the actual question was in the next paragraph. Also, the answer does not seem to address my specific question. So this paragraph:     So my second instinct would then to be to post it into the Stack   Overflow site on the basis that I have a significantly higher chance   of my question being seen and getting a good answer. Then I notice   that there is also a 'programmers' network, and I don't even begin to   know where that fits in. I, and I am assuming most people, will   probably just post on Stack Overflow to be safe.   ...is related to my question, but:     My question is, other than the short little description blurb of each   one, is there a clear cut set of guidelines which what each network is   intended for, what kinds of questions should go to each one, and is   anything being done to encourage people to post in these newer,   smaller (more specialized?) networks as opposed to just posting in big   daddy Stack Overflow?   ...is the specific question that the answer seems to address.


Is external force equal to restoring force

I have reached a confusion. We know $$F=-kx$$ in a spring. If an external mass $m$ is suspended to a spring and the spring extends by a length $x$ and the mass comes to rest,   external force, $~mg = \text{restoring force of spring} ~~kx$ ( talking about the magnitude only here)  Again, at the stopping point, work done by external force will me $mgx$ and potential energy gained by spring will be $$\frac{kx^2}2$$ These terms must be equal as the system is in rest  So $$k\frac{x\cdot x}2 = mgx$$ Cancelling out $x$, we get $$\frac{kx}2 = mg$$ These contradicts the original statement that $mg=kx$  Please help me. I am confused.


How many connected graphs over V vertices and E edges?

Is there a way to calculate the number of simple connected graphs possible over given edges and vertices?   Eg: 3 vertices and 2 edges will have 3 connected graphs But 3 vertices and 3 edges will have 1 connected graph  Then 4 edges and 3 will have 4 connected graphs  Till such values...it is easy to see its  V choose E  But what about when the number of vertices are less than number of edges...how to calculate then?  I am not able to visualize that  Can it be a variation of the Stars and Bars problem  Like...number of ways 7 edges(balls) can be connected to (kept in) 5 vertices(bags) such that no vertex(bag) is isolated (is empty)  Here maybe we might have to consider the number of edges twice as each edge needs two vertices...


Remove the write protection from a USB flash disk

My flash disk encountered an error saying that it has been write protected, so of course I can't even copy files or even format my flash drive.   What happened to my flash drive to cause this?   And is there a way I can I fix this?


After downloading the July 30th update, I noticed the ability to Transfer my Pokemon was gone.    Is this a bug or is everyone experiencing this?


Playing civilization 5 the game explicitly says roads cost gold to maintain. This is of course a  in the answer to .  However, looking at the income report I do not see a "road maintenance" entry, and comparing with the number of roads I have it really feels that they do not cost 1 gold per tile, which is what I assumed from the game description. Further, I'm pretty sure building a single road tile does not affect my income.  So, do roads really cost gold to maintain, and if they do - how does it work? Is it really 1 gold per road tile, regardless of where that tile is?


The set of convergent points of a sequence of continuous functions is Borel

Suppose that $f_n$ are continuous.  Prove that $E=\{x\in \mathbb{R}:f_n(x)\text{ is convergent}\}$ is Borel.   My first instinct is to take balls around $\lim_{n\to\infty}f_n(x)$, for each $x$ in $E$, and then show that there has to be some ball small enough so that everything inside that ball is a member of $E$. But this would imply not only that $E$ is Borel, but moreover that it is open, so I don't think that can be right.  Can someone show me how to do this?


How to copy a 4.2GB file to a USB flash drive

I have a 4.2GB file on my hard disk. I need to put it onto a USB drive to copy it to another PC. However, when I use a standard Windows 10 copying and pasting process, it tells me that the 4GB file is too large for the 16GB drive. So something is not right. How can I get that file onto the USB drive, preferably without using dodgy adware-laced freeware?  The USB drive was formatted at FAT32.


How to correctly cite more than one reference in IEEE style?

I am using ieee.cls and its LaTeX template but I see a problem right away in the citation: I use \cite{ref1,ref2} in my text, and  I expect to get the following output: [1,2].  But I get  this [1], [2].   Please explain why is this happening.


How to install Sharepoint on Windows 10 Pro?

I want to install SharePoint on a Windows 10 Pro PC. How can I do this, and is there any extra software required?


I need to get the size of directory in terminal for signing purposes. I'm using following command:  du -s /path/to/dir   I'm multiplying the result by traditional UNIX block size (512 bytes) and get actual directory size in bytes. However, the Finder's "Get Info" dialog window shows the size slightly smaller than the one calculated with the terminal command. And it seems that it's reproducible on any folder/bundle. What am I missing?


Traditionally  at the end of a filename after uploading it via the image uploader. That doesn't seem to work any more. I've tested it on Q&A as well as chat.        (Yes, I know big M doesn't work)  Could we have this fixed please?


Prove of a finite cyclic group of order $n$ is isomorphic tto $(\mathbb Z_n,+)$.

Show that cyclic group of finite order $n$ is isomorphic to $(\mathbb Z_n,+)$ Actually, the answer to this question is available in MSE but I am not getting it,and one answer is not in the English language.Please kindly give a proof in easy language. Thank you.\ Here is a solution I don't understand:


Why is it possible write this function as a finite sum of entrie functions?

Let $f: \mathbb{C} \backslash\left\{a_{1}, \ldots, a_{n}\right\}$ be holomorphic, prove that there exist entire function $f_0,f_1,...f_n$ s.t $$f(z)=f_{0}(z)+f_{1}\left(\frac{1}{z-a_{1}}\right)+\ldots+f_{n}\left(\frac{1}{z-a_{n}}\right)$$ What I think that this thing can be only true if $a_{1}, \ldots, a_{n}$ are removable singularity of $f$ but how can I infer the kind of the singularity points from that question givens? The reason I think this true only if those are removable points is that it looks $f$ is defined in those points.


If we can interchange left or right join then what is the use of any specific type of join??


So I'm attempting to recreate this specific lollipop for a class. I was able to model the lollipop, but I'm unable to recreate the twist with 4 colors. I tried modeling 4 elongated cubes and using a simple deform to twist them. I got the result I wanted but it wouldn't work if I tried making it follow the spiral path. I also did a screw modifier on a circle and didn't know how to make it follow the spiral path either. How would you approach this in the most efficient way?   Edit: I made the lollipop! Thanks for the help!


How to easily convert fat32 local disk to ntfs? Can I do it without formatting the local disk?


I have 2 ancestors, a father and a mother. Two generations back - 4 ancestors. Three generations back - 8 ancestors.  30 generations back: 2^n = 2^30 = ~1,000,000,000 ancestors.  If a generation is 25 years long, 30 generations are 750 years and 30 generations ago the year was 1,267. But the world population was only 400,000,000 people so how can my math be wrong? and is there a way to estimate the number of ancestors I had 750 years ago?


lost all files by using sudo mount, need help

I have a urgent question which almost make me crazy now.  I used the following command for MATLAB installation:  sudo mount -o loop /home/study/MATLAB/R2017b/iso/iso2.iso /home/caihongzhu   Under /home/study directory, I have all my useful files. After using this command, I lost all files under the /home/study directory (for user caihongzhu).  Thanks a lot for your help!


Adding up floating numbers in javascript

I was wondering about the way JavaScript handles floating points.  I.e. suppose I set 5 variables to (no decimal numbers):  var a = 1/2, b = 1/3, c = 1/12, d = 1/12, e = 0;   Is the sum of these guaranteed to be 1?  The attached answer does not answer my question, I want to distinguish declaring variables of decimal number with defining them as stated above (0.5 vs. 1/2)


Why is my child div overflowing outside of the parent div?

I have always had this problem and I avoid floating div's because of this problem. The code seems to work but when you inspect the code in Google's developer tools it shows that the Main div is 0px tall. the problem I have with this is what if I want the Main div to have an image or a color. The solution I found to getting this to work is applying a float to every div so Main would also get a float but floating the Main div will break the centering of the main container. Does anyone know of a way to fix the two divs going outside of the main div?   .float-left {   float: left; }  .float-right {   float: right; }  main {   width: 100%;   height: auto;   background-color: darkgray; }  .div1 {   height: 200px;   width: 50%;   background-color: darkgreen; }  .div2 {   height: 200px;   width: 50%;   background-color: darkblue; } <link href="https://meyerweb.com/eric/tools/css/reset/reset200802.css" rel="stylesheet" type="text/css">


When i use the XY pack for LaTeX by adding the following line to my source:  \usepackage[all]{xy}   i get this error:  ! No room for a new \dimen . \ch@ck ...\else \errmessage {No room for a new #3} \fi l.192 \xynew@{dimen}\Y@min This error message was generated by an \errmessage command, so I can't give any explicit help. Pretend that you're Hercule Poirot: Examine all clues, and deduce the truth by order and method. \Y@min=\dimen234   I have still missing packages?


Should a collaborator who recently passed away be included as an author?

I am finishing a publication based on my PhD thesis. The writing process took a long time, and a while ago, one of the collaborators passed away. The paper is mostly about the development of a model, but does include some experimental data. The data  have been published before, though I did some additional analyses.   The deceased collaborator was involved in discussions about possible mechanisms that I incorporated into the model, but not in the actual modeling process. The data was collected in his lab. He never saw the manuscript in any state, though he did see my thesis, which has substantial overlap with the paper. Should he be included as an author, or not?


Isn't there a way to close the comment box if you decide to not comment again. Maybe pressing the Esc key or a cancel button.


Vertical and horizontal lines in pgf-tikz

It is easy to produce a path between two nodes consisting of a single horizontal and a single vertical line (from the manual):  \begin{tikzpicture}   \draw (0,0) node(a) [draw] {A}  (1,1) node(b) [draw] {B};   \draw (a.north) |- (b.west);   \draw[color=red] (a.east) -| (2,1.5) -| (b.north); \end{tikzpicture}   However, what if I wanted the same short syntax to produce a path between (a) and (b) using a horizontal line, a vertical line, and a second horizontal line. It isn't to difficult to calculate the intermediate points, but how could the following syntax be defined?  \begin{tikzpicture}   \draw (0,0) node(a) [draw] {A}  (3,1) node(b) [draw] {B};   \draw (a.east) -|- (b.west); \end{tikzpicture}


Is Mackeeper scam/malware? Please give me advice!

I'm not very computer literate, so I need some help with my computer and thought the application will help me to remove the duplicates and other unwanted things from the hard drive. However, I saw many negative reviews on the Net. I'm very frustrated. Thank you!


I'm not sure why I need to use ul-li vs simply using divs when listing items. I can make both look exactly the same so where is the functional advantage to creating an unordered list vs lining up divs?


Get contiguous date ranges in grouped data

CREATE TABLE `rings` ( `ID_RingType` char(2) default NULL, `Number` date default NULL, `ID_User` int(11) default NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1;  INSERT INTO `rings` (`ID_RingType`, `Number`, `ID_User`) VALUES  ('AA', '2018-09-01', 1), ('AA', '2018-09-02', 1), ('AA', '2018-09-03', 1), ('AA', '2018-09-11', 1), ('AA', '2018-09-12', 1), ('AA', '2018-09-13', 1), ('AA', '2018-09-14', 1), ('AA', '2018-09-15', 1), ('AB', '2018-09-16', 1), ('AB', '2018-09-17', 1), ('AB', '2018-09-18', 1), ('AB', '2018-09-19', 1), ('AB', '2018-09-20', 2), ('AB', '2018-09-21', 2), ('AB', '2018-09-22', 2);   I wish to group the data based on ID_User and ID_RingType and for each contiguous range of dates list the MIN and MAX.  The results should look like:    ID_User   ID_RingType    MIN( Number )    MAX( Number )        1      AA            2018-09-01        2018-09-03        1      AA            2018-09-11        2018-09-15        1      AB            2018-09-16        2018-09-19        2      AB            2018-09-20        2018-09-22   This is what i tried :        SET @grp = NULL ;# MySQL returned an empty result set (i.e. zero         rows).       # MySQL returned an empty result set (i.e. zero rows).       # MySQL returned an empty result set (i.e. zero rows).        SET @preNum = NULL ;# MySQL returned an empty result set (i.e. zero        rows).       # MySQL returned an empty result set (i.e. zero rows).       # MySQL returned an empty result set (i.e. zero rows).       SELECT ID_User, ID_RingType, MIN( Number ) , MAX( Number )       FROM (       SELECT ID_RingType, ID_User, Number, @grp :=       CASE WHEN Number = DATE_ADD( @preNum , INTERVAL 1       DAY )       THEN @grp       ELSE DATE_ADD( @grp , INTERVAL 1       DAY )       END grp, @preNum := Number      FROM  `Rings`       ORDER BY ID_RingType, ID_User, Number      )T      GROUP BY ID_RingType, ID_User, grp   Any Help appreciated.


Forgot to Do System Transfer on old 3DS XL, can't login to old NNID

I just picked up the New 3DS XL and never knew about the system transfer until now. I did the 3DS exchange for $100 with GameStop without knowing about it. The GameStop employee didn't inform me either. I have the old SD card from the old system.  Is there any way to unlink the NNID from my old 3DS so I can login into my new 3DS?  Is there any way to salvage the save data from the old 3DS with the SD card I have to put it on the new 3DS?


How can I change the Desktop folder path?

I had some trouble upgrading to 11.10, and had to create a new user and copy some files to my old user to work. But now Ubuntu can't find my Desktop folder. I need to change the path, so where can I change it?


Can compositing be displayed in the viewport render?

I have made an object glow using nodes and cycles render. when I hit the render button in the properties panel it glows fine but when I go into the rendered view it won't glow. Is this even possible?  Rendered when render button is clicked:    Rendered in viewport:


I’m self-studying physics and mathematics out of interest and I am looking for some non-rigorous (text)books on mathematics. Perhaps one book covering all areas relevant to physics or separate books in the areas of non-linear dynamics, differential equations, differential geometry, group theory, etc.  I am explicitly looking for non-rigorous, intuitive approaches to these fields. I feel overly rigorous books make the material needlessly difficult (to me often impossible) and slow to read.  I am looking for things in the style of student’s guides, such as Dan Fleisch’s “A Student’s guide to vectors and tensors” but then more expanded:   Also, a mathematics book that shows the bigger picture on mathematics would be of interest. Something more or less popularising.


Here is my Python2 script, test.py:  x = sys.argv[1] y = 'foo' print(x) print(y) print(x is y)   I then call my script with python test.py 'foo'. This prints out:  foo foo False   But both x and y appear to be the same value, 'foo'. So why is this equivalence test returning False?


Can 'home' be an adjective as well as an adverb or a noun?

All the dictionaries I've consulted say that 'home' is an adverb and a noun, depending on context. For example:  (1) He went home. [adverb] (2) He is at home. [noun]  Also, there's  that seemingly resolves the issue of why 'home' sometimes should be analyzed as an adverb. But what about this example?  (3) I can find my way home.  Can you also say that home in (3) is an adverb? It seems to me that home in (3) cannot be an adverb, because I think it functions as a complement of the noun way and that my way home as a whole is a noun phrase. Even if we accept John Lawler's analysis in the above quoted answer of considering home "one of those idiomatic locative nouns that are allowed to drop determiners and occasionally even prepositions," we cannot say home in (3) is an example of "how a noun can be used as an adverb", because (3) can be analyzed as John Lawler suggests:  (3') I can find my way (to my) home.  Here, to my home is not an adverbial prepositional phrase but an adjectival prepositional phrase that acts as a complement of the noun way. So, to take what John Lawler said and adapt it to (3), "what it is is an [adjectival] prepositional phrase that has been stripped of its prepositions and determiners, leaving only a naked noun to stand for the whole phrase. That's how a noun can be used as an [adjective]." Now, does this mean we should call home a noun, an adverb, or an adjective, depending on context?


I am curious about the following problem:  Can we show that the set $\{p(x)\cdot\exp(-x^2/2)\}\subseteq L^2(\mathbb{R})$, where $p(x)$ is any real-domained polynomial function (i.e., functions in the form of the product between a polynomial function and the exponential function $\exp(-x^2/2)$), is dense in $L^2(\mathbb{R})$?  I am confident in this claim, but fail to prove it. The barrier to me is how to properly use the Stone-Weierstrass theorem (if we need to use it), as it only works on a compact set. Can anyone give me some hint or suggestions? Many thanks!


How do I solve Java error java.lang.NullPointerException for my code?

case 7 :             scan.nextLine();             System.out.println("Ievadiet reisa sākuma staciju");             k = scan.nextLine();             System.out.println("Ievadiet reisa gala staciju");             v = scan.nextLine();                 for(i=0; i<50; i++){                  for(j=0; j<5; j++){             if(A[i][0].equals(k) && A[i][1].equals(v) && A[i][j]!=null)                         System.out.println("Biļetes cena:"+A[i][4]);                 }                 if(A[i][j-1]!=null)                     System.out.println();             }             break;   I can't find a solution for my problem. I need to print on screen the lines with asked text content. Everything works but in the end it shows this error. Can anybody help?


What is the best practise to relase Excel interop objects in C#?

I have a function basically to convert an excel file to text file. The structure is like following. What I am concerned is the Finally part? Is it a best practise to kill the excel?   Excel.Application excel=new Excel.Application(); Excel.Workbook wb=excel.Workbooks.Open(…);  Try  {    …    Foreach(Excel.Worksheet sheet in wb.Sheets)    {       …       Marshal.RealseComObject(sheet);    }    … }  Catch() { }  Finally {    wb.Close(false, missing, missing);    while (Marshal.ReleaseComObject(wb)!=0)    {    }    wb=null;    excel.Quit();    while (Marshal.ReleaseComObject(excel)!=0)    {    }    excel=null;    GC.Collect();    GC.WaitForPendingFinalizers(); }   Update:  I have following version of Finally  Finally{ wb.close(false, missing, missing); excel.application.quit(); excel.quit();  Marshal.ReleaseComObject(wb); Marshal.ReleaseComObject(excel); GC.Collect(); GC.WaitForPendingFinalizers(); }   Which one is better (make more sense)? I have checked all the links here, but there is no finally answer, everybody's answer is sightly difference. I am not sure which one is the best?


Sequence converge with an floor function.

I spent the last few hours evaluating this converge. I am pretty sure it converges. However, I am not able to prove it. Can you help me? I have already proven it absolutely diverges.  $$\sum_{n=1}^\infty \frac{(-1)^{\lfloor\sqrt{n}\rfloor}}{n}$$  I have tried to apply both the Abel and Dirichlet criteria. I got to the point, where I need to prove that $$\sum_{n=1}^\infty \frac{(-1)^{\lfloor\sqrt{n}\rfloor}}{\sqrt{n}}$$ is bounded, which is unresolvable for me as well.


What does Dumbledore see in the Mirror of Erised?

We know from the first book that Dumbledore guessed what Harry must be seeing in the Mirror of Erised (his family, assuming Dumbledore cannot directly see the Mirror anyway - which could be a possibility since he could alter it).  In the chapter in which this happens, JKR doesn't immediately reveal what Dumbledore sees when he looks in the Mirror.  Is it later revealed by JKR what Dumbledore sees when he looks in the Mirror of Erised?


Why all c programs should start with a main() that returns a `int`?

I like to know what is the main reason that all C programs should start with the standard function of "int main()"? and why it should be "int" ? Thank you


SFDX: Create a version for an unlocked package

I'm trying to create an unlocked package for all custom objects, custom fields, page layouts. Creating the package itself is going well, but when I tried to create a version, it failed with a very long list of errors!  I read them, and it seems that for some of the errors the problem is that when creating a version some features like (PersonAccount, ...etc) are not found   here is a link to the full list of errors:   these are some of the errors:   Account: The entity: Account does not have history tracking enabled,CaseMilestone: Invalid fullName, must end in a custom suffix ( for ex. __c ),AccountContactRelation: Invalid fullName, must end in a custom suffix ( for ex. __c ),MLModel: Invalid fullName, must end in a custom suffix ( for ex. __c ),ForecastingTypeToCategory: Invalid fullName, must end in a custom suffix ( for ex. __c ),Entitlement: Invalid fullName, must end in a custom suffix ( for ex. __c ),Case.SlaExitDate: Could not resolve standard field's name.,Case.SlaStartDate: Could not resolve standard field's name.,Case.SourceId: fullName must end with: __c or __kav or __x or __b or __xo or __e or __p or __mdt,DuplicateRecordSet: Invalid Type Exception,ForecastingOwnerAdjustment: Invalid fullName, must end in a custom suffix ( for ex. __c


Prove that it is not a Principal Ideal Ring

I am scratching my head on how to go about proving the statement that $F$ being a field implies $F[x_1,x_2]$ is not a principal ideal ring. I believe that the best method would be to initially assume for the sake of contradiction that $F[x_1,x_2]$ is a principal ideal ring. Then, given any ideal in $F[x_1,x_2]$, said ideal can be of the form of a cyclic group for a given element in $F[x_1,x_2].$ I can't seem to figure out an optimal path to move from here to solve this problem. Any suggestions?


How to trigger power bank to output 12V?

I have a  power bank that can output 5V fast charge or, 5V 9V or 12V regular charge.   I am using this voltage trigger to get the 12V output desired but I have a special condition.  The power bank will be secured away and I will not be able to access the buttons to change it to the mode needed. I soldered a wire to the positive and negative side  of the "up" button on the voltage trigger. I did the same for the "mode" button as well.  I wrote a small program that reads the Voltage output of the power bank using a voltage divider to have the ~12V match the top voltage that the arduino can read. When the power is not at the right setting it sends a signal to an N-channel MOSFET to simulate the button being clicked and change the voltage level.   When I touch the positive and negative wires that I soldered to the "up" button for about 700ms the voltage  output changes. I've tried a HIGH pulse and a LOW pulse at different lengths between 700 -1500 ms with the N-channel MOSFET that doesn't quite work.  The problem is that sometimes the voltage trigger toggles between the power levels without any influence. Even when all wires are disconnected and its just the power bank and the trigger. That makes it difficult/impossible for me to be sure  that my program is running correctly, or that I can rely on it to set the output to 12V  What options do I have to get  the power bank to output 12V without needing to manually do anything?


I encountered the integral $$\int_0^1 \frac{\log \left(1-x^2\right) \sin ^{-1}(x)^2}{x^2} \, dx = -0.9393323982...$$ while researching the evaluation of harmonic sums. Mathematica 11 is not able to evaluate this integral, and is not able to evaluate the underlying indefinite integral.  I considered using the Maclaurin series for the expression $\sin ^{-1}(x)^2$ to evaluate this integral. Using this Maclaurin series, it is easily seen that the problem of evaluating the above integral is equivalent to the problem of evaluating the series $$\sum _{n=1}^{\infty } \frac{2^{2 n-1} H_{n-\frac{1}{2}}}{(1-2 n) n^2 \binom{2 n}{n}}=-0.9393323982...$$ which Mathematica 11 is not able to evaluate directly.  I also considered using the Maclaurin series for the expression $\log \left(1-x^2\right)$ to evaluate the above integral. Using this Macluarin series, it is easily seen that this integral is equal to $$\frac{1}{4} \left(16 \pi  C-\pi ^3-\pi ^2 \log (4)\right)+\sum _{n=1}^{\infty } \frac{\, _3F_2\left(\frac{1}{2},\frac{1}{2},1;\frac{3}{2},n+1;1\right)}{n^2-2 n^3}=-0.939332...,$$ but Mathematica is unable to evaluate the above infinite series.  What is a closed-form evaluation of $\int_0^1 \frac{\log \left(1-x^2\right) \sin ^{-1}(x)^2}{x^2} \, dx$? What techniques can be applied to evaluate this definite integral?


Unclear terms: Statement of Purpose, Academic Statement and Personal Statement

I'm so confused. I can't distinguish between them. It seems to me that sometimes the statement of purpose (SOP) is the personal statement (PS), sometimes it is not the PS, and by the definition I'll give below, academic statement (AS) is the SOP. Is the SOP a PS (or not)? I think most people will agree that the SOP is another name for the PS, and you only need one statement beside your CV and research proposal (if necessary) to be written. That explains why in Academia.SE, we only have a  tag but no PS tag or AS tag. And most of the time I see people ask about a PS question under the SOP tag, and accept the answer only says about the SOP. Except these two questions, where the posters notice that SOP is not the PS (I find them when searching for ):     To be clear, the first question asks about academic statement of purpose and only localize to the NSF Fellowship application. But the (sole) answer only discusses the SOP, so I understand that ASOP is the other name of the SOP (don't know if it also be the AS as well). Is the SOP the Academic Statement? Now, in the , it requires me to have both an academic statement and a personal statement. It defines them like this:  ACADEMIC AND PERSONAL STATEMENTS. Each applicant must prepare a one-page Academic Statement and a one-page Personal Statement. The first essay addresses the applicant’s academic and scientific background and preparation, previous research, and a description of the study and research proposed at a U.S. graduate school department. The Personal Statement includes information about the applicant’s background, practical experience, special interests, and career goals, with some attention to plans after degree completion. Applicants should also address how they might represent Vietnam as students in the United States and how they might represent the United States and contribute to Vietnam upon return.  More explicit details are provided in the link. Based on the definition of the AS, I think that it is the SOP as we widely know (or at least is ). If then, what is the PS in this case? Is it the place for the "my first trembling steps" stuff? Or, does the aggregation of AS and PS in this situation equate the SOP as we widely know, and the recruiters just want to make it explicit?


Need help recalling name of sci-if story about earth evolving into electronic life forms

Read a story once about earth being abandoned for long periods of time. Upon the return of man to earth all life forms, flora and fauna, have evolved into intricate electronic forms of themselves.   Would like to find that story and it's name.


Shortcut or script to open Screen Sketch on Win10

Does anyone know a shortcut or even an AutoHotKey script that opens Screen sketch directly? i know that the shortcut Win+W opens Windows Ink Workspace but i have to select screen sketch afterward (which is annoying). Any help appreciated.


Provide links to candidate questionnaire answers in elections

Elections generally have a meta question, linked to in bold at the top of the election page with the text "The candidates answer your questions."    Can we include, in each candidate's nomination box, a link to the candidate's answer on that particular meta question, appropriately labelled?   I noticed in the , there are some candidates whose nomination text includes a link saying something like "," which appears to have been edited in by the candidate directly.  However, when an election has no primary (e.g. the ongoing election at ), it's impossible for a candidate to edit that in because that meta question .    Yes, one can get to it indirectly through "meta posts" or through the bold link above the list of candidates, but the percentage of voters who figure out that the election Q&A is really just a meta question and that answers are "posts" might not be that large, even among the subset of voters who know what meta is.


Nested environments to scale tikzpicture

I found  nice solution to scale a TikZ picture to \textwidth and wanted to use it within an own defined environment.   \documentclass{article} \usepackage{tikz}  \usepackage{environ} \makeatletter \newsavebox{\measure@tikzpicture} \NewEnviron{scaletikzpicturetowidth}[1]{%   \def\tikz@width{#1}%   \def\tikzscale{1}\begin{lrbox}{\measure@tikzpicture}%   \BODY   \end{lrbox}%   \pgfmathparse{#1/\wd\measure@tikzpicture}%   \edef\tikzscale{\pgfmathresult}%   \BODY } \makeatother  \newenvironment{bggrid}[1]{% \begin{scaletikzpicturetowidth}{#1\textwidth}% \begin{tikzpicture}[transform shape, scale=\tikzscale] \draw (-2,-2) grid (2,2); } {\end{tikzpicture}\end{scaletikzpicturetowidth}}  \begin{document}  % works perfectly % \begin{scaletikzpicturetowidth}{.5\textwidth}% % \begin{tikzpicture}[transform shape, scale=\tikzscale] % \draw (-2,-2) grid (2,2); % \draw (0,0) circle (1); % \end{tikzpicture}\end{scaletikzpicturetowidth}  % this causes the problem  \begin{bggrid}{.5} \draw (0,0) circle (1); \end{bggrid}  \end{document}   But when I do so I obtain an error, I was not able to fix.  ! LaTeX Error: \begin{scaletikzpicturetowidth} on input line 35 ended by \end{d ocument}.  See the LaTeX manual or LaTeX Companion for explanation. Type  H <return>  for immediate help.  ...                                                l.39 \end{document}  ? h Your command was ignored. Type  I <command> <return>  to replace it with another command, or  <return>  to continue without it.   Does somebody has any idea how to solve this?


Can I recover data from lost partitions?

I had Windows 7 and Windows 8 dual booted. I tried to install Ubuntu 14.04 by deleting Windows 8, but unfortunately whole hard disk wiped. Now I have only Ubuntu 14.04 installed using whole hard disk size. I'm at a loss now after losing my project data.  I had 3 NTFS partitions other than the Win 7 and Win 8 partitions.  Can I recover my data? If possible how?  Thanks