Show that the Cauchy problem $x''=x|x|,x(0)=a,x^{\prime}(0)=b$ ,has a unique solution for all $a,b\in \Bbb R$.

Show that the Cauchy problem $x''=x|x|,x(0)=a,x^{\prime}(0)=b$,has a unique solution for all $a,b\in \Bbb R$. (The Problem is from A text book on ordinary differential equation by Shair Ahmad and Antonio Ambrosetti,exercise 4.3,pg:70)  My attempt:  I am using this theorem(given in book,page 69):  $\begin{cases} x^{(n)}=f(t,x',x'',...,x^{(n-1)})\\              x(t_0)=\alpha_1,x'(t_0)=\alpha_2,...,x^{(n-1)}(t_0)=\alpha_n      \end{cases}$                                         (1)  If $f:\Omega \to \Bbb R$ is continuous and locally lipschitzian with respect to $(x_1,x_2,...,x_n),$ then (1) has a unique solution,defined in a suitable nbd of $t_0$.($\Omega$ is an interval containing point $(t_0,\alpha_1,...,\alpha_n)$)  (The function $f$ is called locally lipschitzian at  $(t_0,\alpha_1,...,\alpha_n) \in \Omega$ with respect to $(x_1,x_2,...,x_n)$ if $\exists$ a neighborhood $U \subset \Omega$ of $(t_0,\alpha_1,...,\alpha_n)$ and a number $L>0$ such that, denoting by $|.|$ the euclidean norm in $\Bbb R^n$, one has   $|f(t,x_1,x_2,...,x_n)-f(t,z_1,z_2,...,z_n)|\leq L |(x_1,x_2,...,x_n)-(z_1,z_2,...,z_n)|$ for every$(x_1,x_2,...,x_n),(z_1,z_2,...,z_n) \in U$. )  clearly $f$ is continuous.therefore we will show that $f$is lipschitzian at point $(0,a,b)$.  To prove lipschitzian at point $(0,a,b)$ we have to show that $\exists$ a nbd U of $\Bbb R^3$ containing point$(0,a,b)$ and a number $L>0$ such that  $|f(t,x,x_1)-f(t,z,z_2)| \leq L||(x,x_1)-(z,z_1)||$   $\forall (t,x,x_1),(t,z,z_1) \in U$  here $||(x,x_1)-(z,z_1)||=\sqrt{(x-z)^2+(x_1-z_1)^2}$  Now $x|x|$ is differentiable everywhere on $\Bbb R$.therefore it is locally lipschitz on any finite interval of $\Bbb R$. therefore we have (for finite interval)  $|x|x|-z|z||\leq L|x-z|$ for some number $L$.  Now   $|x|x|-z|z||\leq L|x-z| \leq L \sqrt{(x-z)^2+(x_1-z_1)^2}$  $\therefore$$|f(t,x,x_1)-f(t,z,z_2)| \leq L||(x,x_1)-(z,z_1)||$   $\forall (t,x,x_1),(t,z,z_1) \in U$ where $U$ is any nbd of finite radius of $\Bbb R^3$ which contains the point $(0,a,b)$  Hence given problem has a unique solution for all $a,b\in \Bbb R$.   I am confusing whether am I correct or not?If it is not correct then where am I making mistake?and how to solve this problem?Thank you in advance.


Why is neutron slightly heavier than the proton?

With latest knowledge of QCD, is there any explanation for why the neutron is slightly heavier than the proton? Can it be boiled down to a simple formula?


Latex biber gives me [0] for cites using JabRef

Hi guys I'm having an unresolvable problem with my LaTeX document (at least for me).  Here are my first two entries from the references file:  % Encoding: UTF-8  @Article{FelixWortmann2015,   author       = {Felix Wortmann, Kristina Fluechter},   title        = {Internet of Things - Technology and Value Added},   journal      = {Springer},   journaltitle = {Business \& Information Systems Engineering},   year         = {2015},   date         = {2015-03-27},   url          = {https://link.springer.com/content/pdf/10.1007/s12599-015-0383-3.pdf}, }  @Online{Lueth2016,   author = {Knud Lasse Lueth},   title  = {OVERVIEW OF 640+ ENTERPRISE IOT USE CASES},   year   = {2016},   date   = {2016-08-11},   url    = {https://iot-analytics.com/global-overview-640-enterprise-iot-use-cases/}, }   Here are my headers for the document:  \RequirePackage[utf8]{inputenc}  \graphicspath{{images/}} \logofile{logo} \bibliography{references}    in my project folder there is an "references.bib" and a "references.bib.bak" file (containing all the sources)  Now when creating my pdf-file i get all [0] instead of the correct number. My texnic center gives me this output:     pdflatex> LaTeX Warning: Citation 'Repschlaeger2014' on page1 undefined on input line 75   pdflatex> There were undefined references.   pdflatex> Package biblatex Warning: Please (re)run Biber on the file   I get the same warning for a number of citations. Please tell me if you require any more information.


What is the $d/dt$ in the Schrödinger equation?

I'm wondering, in the Schrödinger equation, $$ {\displaystyle i\hbar {\frac {d}{dt}}\vert \Psi\rangle ={\hat {H}}\vert \Psi  } $$ what is the $ {\displaystyle {\frac {d}{dt}}} $ ? I understand it has to do with time, t, but I guess i'm hoping for some more understanding into what d is and how this derivative works, and what it means to the whole.


How to get the new location of an object after a lattice deform?

I am using a lattice to displace an object and I would like the new location of the object after the lattice deform happens. I am trying to do this through the Blender API. ob is my sphere. ob.location is still giving me 0,0,0 and when I look at the 3D Viewport it also shows 0,0,0.


I would like to integrate Windows 8 integrate into grub without its loader. Can I do this? If yes, how? Loader loads slowly.


Reminding new users of accept/upvote "duty"?

I often see new users posting questions and getting answers. But instead of getting an upvote or accept for the answer, they just add a comment that the answer helped them.  I understand that you need 15 points minimum for upvote.  I often see people then commenting "when you are happy, please accept / upvote".  My impression is that the new users don't really know about the upvote/accept business.  So my idea is if the system could send them some automatic and more explicit message when they have earned > 15 (or another threshold) points in the sense of "Now you have x points, and posed some questions. Please review the questions and vote / accept answers given"


What was the command of "Fire at will" before gunpowder?

I've seen some discussions about the command of "fire" before gunpowder was invented. That may be "shoot", "loose", "throw" etc. But what was the command of "fire at will"?  Are there any clues?  Update:   "Fire at will" is a tactic which has long existed in history. After the invention of gunpowder, we call it "fire at will". Before gunpowder, what did we call this tactic? Was there a common used phrase or not?


Changed website permalink structure. Old permalinks show as duplicate content in webmasters tools

I have changed the permalink structure for a website containing about 2000 URLs. The old urls are 301 redirected to the new ones.  Google indexed most of them yet they show as duplicate titles in webmasters tools.  The thing is that after I changed the permalink structure I also changed the Title structure. So considering the fact that google sees the NEW title structure for the old urls it clearly shows that they were re-crawled, but instead of de-indexing them, they are shown in webmasters tools with a notice saying they are duplicate pages of the new ones.  Any idea why this happens ?  I would have expected the new permalinks to replace the old ones and for Google to NOT keep the old ones in the index too and consider them duplicates.  Thank you.


Changes Aren't Saved After Shut Down - Ubuntu 16.10 Live USB

I want to use Ubuntu 16.10 from my 8gb usb pen-drive. I've noticed that whenever I make any changes to it they all get reverted after shut down.  All the files I have downloaded, documents, etc, get automatically deleted.  Everything else is working completely fine except no changes are saved.


Getting an IDE mode installation of 7 to run in AHCI mode?

I installed windows 7 a few months ago while my SATAs in my bios were configured as IDE. When I change it to AHCI for an added speed boost, I get a BSOD on startup. Is there a way or tool I can use to get my OS to boot in ahci mode without reinstalling windows?  I tried the windows recovery and start up fixes but they did not work.  Thanks


I know it's not supported natively for some reason, but I'd really like to lay back on my couch and enjoy the game in a relaxed position instead of sitting straight up at the table with more keys than I need under one of my hands.  Is there a way to play Diablo 3 with a gamepad?  I'm interested in solutions for any kind of PC-compatible gamepads, so please specify which ones your solution supports.


Another Olympiad problem about prime number

p is a prime number Let $m,n \in \mathbb{N}$.  Find $m,n \ \text{and} \ p$ ,such that:  $$\frac{p+m}{p+n}=\frac mn+\frac {1}{p^2}$$  I don't know even how to start I need your help any suggestions please


How can I use a variable string within command substitution?

I'm attempting to create this command and it fails because the desc variable is being interpreted separately instead of a quoted string. I've tried many variations of quoting with and without using single quotes to make text literal including the my latest attempt below.  If I call the function using:  new_proj "FALSE" "TRUE" "This is a test" "path" "to"   function  new_proj(){   [ "$1" = "FALSE" ] && local p="p"   [ "$2" = "TRUE" ] && local o="o"     local sw="$p$o"   [ ! -z $sw ] && sw="-$sw"   local desc="$3"   local account="$4"   local name="$5"   local create=$(echo mycmd "$sw" -d "desc" "account"/"name")   if $create; then     echo "created."     return 0   else     echo "failed!"     return 1   fi }   Expected result - mycmd -po -d "This is a test" path/to


How to detect when a user has successfully finished downloading a file in php

I've got a php page which handles requets for file downloads. I need to be able to detect when a file has been downloaded successfully. How can this be done? Perhaps there's some means of detecting this client-side then sending a confirmation down to the server.  Thanks.  Edit: By handle, I mean that the page is doing something like this:  $file = '/var/www/html/file-to-download.xyz';   header('Content-Type: application/octet-stream');   header('Content-Length: ' . filesize($file));   header('Content-Disposition: attachment; filename=' . basename($file));   readfile($file);


Say you don't have a dark elixir storage, then you raid somebody who does and gain 500 dark elixir. What happens to that dark elixir? Is it unobtainable? Just gone?  Thanks


In our application, when one deletes a room, a notification message pops up. It says "Your room has been deleted successfully". I have been taught that adverbs are often supposed to precede the verb, as in "Your room has been successfully deleted". However the original version with the adverb at the end does sound somehow appropriate to me, although I can't tell why.   Your room has been deleted successfully.    Your room has been successfully deleted.   Which version is preferable? Are they both grammatical?


Any open or closed subset of a locally compact space is also locally compact

I found this question in an exercise on a book:     Check that any open or closed subset of a locally compact space is also locally compact.   The definition of locally compact in the book is the following: a Hausdorff space is locally compact if for each point there is a compact neighborhood.  There is no other mention to this concept in the entire book, so I assume that a subset is locally compact if seeing it as a topological subspace then it is locally compact (Im not sure if this is the intended use of the concept for subsets).  But then is trivial that any subset of a locally compact space is also locally compact because any closed set and any open set of a subspace is induced by closed and open sets of the general space.  In other words: I cant see any reason that make me think that open or closed subspaces have a different behavior than any other subspace as locally compact spaces. It is my reasoning correct?  In other words: its possible that a subspace of a locally compact space would not be locally compact?


Real number with lower limit topology is not 2nd countable

I find it hard to prove that R with lower limit topology is not second countable.  Let's construct a collection B consists of half-open interval [a,b) where a,b $\in$ Q, so there's a mapping from B to Q x Q which is a countable set  Consider an arbitrary open set [x,y), then there's an open set [q1,q2) $\subset$ [a,b) such that q1,q2 $\in$ Q which means B is a countable basis for lower limit topology which means R with lower limit topology is 2nd countable  P/S: I've read some of other posts on this but nothing gave me a satisfied answer


Why is IIS 10 serving content using HTTP 1.1 instead of HTTP 2?

I have a base install of IIS 10 on Windows Server 2016 which I have setup my basic web application on.   The application website uses HTTPS.  For some reason, when browsing from Chrome 63, the content is served using HTTP/1.1 when I expected it to be served over HTTP/2. I have checked the IIS logs which show:  #Software: Microsoft Internet Information Services 10.0 #Version: 1.0 #Date: 2018-02-09 16:32:34 #Fields: date time s-ip cs-method cs-uri-stem cs-uri-query s-port cs-username c-ip cs-version cs(User-Agent) cs(Referer) sc-status sc-substatus sc-win32-status time-taken 2018-02-09 16:32:38 196.44.182.180 GET /uploaded/a87f9d27-3732-426f-80cb-ac531579a908.jpg - 443 - 196.44.177.71 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/63.0.3239.132+Safari/537.36 https://xxxxxxx/ 200 0 0 46   Interestingly, when I use  to check if HTTP/2 is supported by my web application, it says "Yeah! xxxxx supports HTTP/2.0"  But when I use Chrome or Lighthouse (to test) it tells me content is being served over HTTP/1.1


By the time data on whether they met the targets are made public, Mr Trump could be long gone.  i) The verb "are" takes which subject ? ii) How to understand/ find out the subject in this type of sentence? iii) what kind of sentence is this and what is the meaning of second clause?


Erased Windows 8.1 after installing Ubuntu

My issue is a little bit different than anything I've found so far on the forums. I had successfully installed Ubuntu on my Windows 8.1 hp laptop using the manual partitioning method (not the "install alongside windows 8" way). Today my Ubuntu was being weird and the mouse was blinking and all the text was resizing over and over again, and my shutdown button actually popped up the "lock" and "log out" options instead of the "shutdown" and "restart" options.   So I rebooted Ubuntu using LiveUSB and installed it again, and a message showed up saying "Ubuntu 14.04 detected", and the 2 options were "install Ubuntu 14.04 alongside Ubuntu 14.04" and "erase Ubuntu 14.04 and do a clean installation of it (or something like that)". I thought the second option would only affect my Ubuntu partition, so I selected it. Then I restarted my computer and found that my entire hardrive now was taken up by Ubuntu.   Is there a way for me to get back my windows partition? Would installing windows with LiveUSB and then restoring it with the backup I created work?


How to check if all property values are true?

var myData = {   "value1": {       "ext": false   },   "value2": {       "ext": false   } };  myData.value1.ext = true;   How can I loop through myData to see if the ext for all the properties in my object are true?  Something like this:  if (value1.ext === true && value2.ext === true) {      //do something }


Should I include details about extracurricular art projects on a grad program application?

I'm in the process of applying to graduate programs in a field unrelated to music. I write, record, and perform original music in my free time. Normally I would not mention this in a personal statement; however, one of the programs I am applying to has an additional statement where I am to discuss ways in which I would add to the diversity of the school. I do have material I hope to discuss that falls within normal parameters of relevance, but I am wondering if it would also be appropriate (or rather, not obviously inappropriate) to mention my creative projects? I would obviously attempt to mention them in a way that demonstrates personality traits about me (creativity and drive), rather than just an irrelevant aside.  Any help would be appreciated. Please let me know if there's any additional info I can provide.


Why is the $\rho^0 \rightarrow \pi^0 + \pi^0$ decay not allowed? I have seen  but I am not satisfied with the answers. The $J^{PC}$ of the $\rho$ and $\pi$ are $1^{--}$ and  $0^{-+}$ respectively. Taking the orbital angular momentum of the final two pions state to be $1$ seems to conserve everything ($J$, $P$, $C$, etc.) but is apparently not allowed by the spin-statistics theorem. The answers I have seen say that $L=1$ for the pions gives an anti-symmetric wavefunction. Assuming this is true, I understand why this is not allowed under the spin-statistics theorem, but I don't understand why the wavefunction anti-symmetric; that is the main question.


Should there be a way to close a question as a duplicate of a question from another site?

We had this question on .     Which is a duplicate of this question from .    Is there/should there be a way to close the question as a duplicate of the question from the other site?


Why must a fundamental particle's spin be a multiple of $\frac 1 2$?

A fermion is a particle whose spin is an odd multiple of $\frac 1 2$, and a boson is a particle whose spin is an integer. From what I've seen, these appear to be the only two possibilities; not only have no particles been discovered with a spin of, say, $\frac 2 3$, it seems as though that's not even considered to be a possibility (in contrast, as I understand, there could be a spin $\frac 3 2$ particle, but it happens that none have ever been discovered).   Why is this the case? Or am I mistaken? Sorry if this question has been asked before, I couldn't find any like it.


Accidentally unloaded all launchctl daemons and now can't boot

While trying to set up some services (OS X 10.10 Yosemite), I accidentally did a sudo launchctl unload -w /System/Library/LaunchDaemons/ and the screen was frozen immediately. Now my Mac doesn't boot any more. The loading bar is half full, and nothing happens.  Is there a way to restore the daemons with some kind of rescue console? Unfortunately, I don't have a working time machine backup, my external hard drive crashed some days ago.  I can still boot into recovery mode, using Cmd+R while booting. I can also access the terminal. I tried a launchctl load -w /System/Library/LaunchDaemons/ but it said ‘Operation already in progress’ for every process.  When trying to load the LaunchDaemons files, I was on the rescue partition. After switching to /Volumes/Macintosh HD/System/Library/LaunchDaemons/ and doing a launchctl load -w /Volumes/Macintosh HD/System/Library/LaunchDaemons/ I got some errors with File already exists, but some other Daemons seem to load.  But I suspect, that they are loaded into the rescue system. So I also tried to use the launchctl file of /Volumes/Macintosh HD/bin/launchctl. But unfortantely, same result, the screen stucks with a half progress bar during startup.  I had a look into the verbose startup (pressing Cmd+V at startup). The last lines, where everything stops are  hfs: mounted Macintosh HD on device root_device XCPM: registered VM Swap Subsystem is ON Darwin Bootstrapper Version 2.0.2: Mon Mar.... boot-args = -v ** /dev/rdisk1 (NO WRITE) ** Root file system    Executing fsck_hfs (versoin hfs-285) Warning: couldn't block sleep during cache update Warning: proceeding w/o DiskArb /dev/disk1 on / (hfs, local, journaled) BootCacheControl: Unable to open /var/db/BootCache.playlist: 2 No such file or directory Bash: /etc/rc.server: No such file or directory USBMSC Identifier (non-unique): 0000000... bash: /etc/rc.installer_cleanup: No such file or directory AppleUSBMiltitouchDriver::checkStatus - received Status Packet, Payload 2: device was reinitialized   I also tried to reinstall Yosemite over my old system (without deleting the filesystem, so my data is still there). Unfortunately, the problem stays the same.  Now I can log in in single-user mode (I had to press an additional Enter). After that, I set the filesystem to read with mount -uw /. Then I load all the daemons with launchctl load -w /System/Library/LaunchDaemons. And then, surprise it loads my Mac's login screen, and I can login.  But when I try to restart, I have to repeat that step to login (which is kinda annoying…). I also tried to load all daemons with launchctl load -w /System/Library/LaunchDaemons when I'm logged in.  Here I get ‘Operation already in progress’. I read something in the single-user mode that the loading of services is not supported. Does this affect the fully loaded OS X too? I'm not sure if I'm still in single-user mode or not. How can I tell OS X to load all the LaunchDaemons on startup?


Do I need a User CAL for a record in AD if the user is not authenticating?

We are considering expanding our user provisioning to cover a large portion of the workforce that does not currently exist in AD.  Our understanding is that any named user in AD requires a User CAL.  Is that correct even if the employee will not be authenticating or have an email address assigned to them?


Java prints array memory address rather than array contents

I have created a function which finds the maximum of groups of 3 in my array. When I come to print this, the memory address [I@43c46747 gets printed instead of the maximums which should be contained within the array.   I am not allowed to use any import statements/ anything advanced to solve this - trying to possibly use a helper function?  Thanks :)


How access public websites via Local SSH tunneling?

I just learned about different types of SSH tunneling. First off the list was local ssh tunneling. To try it out, I ran this command, ssh -NL 6454:google.com:80 host  but it didn't work as expected, localhost:6454 threw a 404 page saying, The requested URL / was not found on this server. That’s all we know.  even http://localhost:6454/search?q=hello didn't work The requested URL /search was not found on this server. That’s all we know.  I tried this for other websites like youtube and yahoo but neither of them worked. The only address I was able to access was localhost:8000 of the host server. Why is this command failing for these public websites?


Using cat index.html | grep 'src.*js' I got these results:  <script src="/c/dam/cdc/j/adrum.js"></script> <script type="text/javascript" src="/c/dam/cdc/j/targeter-bundle_min.js"></script> <script type="text/javascript" src="/etc.clientlibs/clientlibs/granite/jquery.min.js"></script> <script type="text/javascript" src="/etc.clientlibs/clientlibs/granite/utils.min.js"></script> <script type="text/javascript" src="/etc.clientlibs/clientlibs/granite/jquery/granite.min.js"></script> <script type="text/javascript" src="/etc/clientlibs/foundation/jquery.min.js"></script> <script type="text/javascript" src="/etc/clientlibs/foundation/shared.min.js"></script> <script type="text/javascript" src="/etc.clientlibs/clientlibs/granite/lodash/modern.min.js"></script> <script type="text/javascript" src="/etc/clientlibs/foundation/personalization/kernel.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/clientlibs/responsive/js/foundation.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/context-banner/clientLib.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/libs/u.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/libs/nmsp.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/libs/log.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/libs/metrics.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/libs/utils/dynamic-video-init.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/libs/base.min.js"></script> <script type="text/javascript" src="/etc/designs/cdc/dmr/bundles/dmr.min.js"></script> <script src="/etc/designs/cdc/dmr/libs/dmimg.min.js"></script> <script src="/c/dam/assets/dmr/three-marquee/dmh-marq3_min.js"></script> 100 48065    0 48065    0     0   140k      0 --:--:-- --:--:-- --:--:--  140k<script type="text/javascript" src="/etc/designs/cdc/dmr/mosaic/clientLib.min.js"></script> <script id="sprinklr-embed-loader-1035-ZW1iZWQ6NWJjZjJhZDAxNjIzYWUxYTM0YzRlOTg0" type="text/javascript" src="https://gallery.sprinklr.com/clients/1035/embeds/ZW1iZWQ6NWJjZjJhZDAxNjIzYWUxYTM0YzRlOTg0/script.js"> <script type="text/javascript" src="/etc/designs/cdc/clientlibs/responsive/js/homepage.min.js"></script>   But I want to extract the strings that begin with src= and end with .js.   Like this:  src="/etc.clientlibs/clientlibs/granite/jquery.min.js"


To have GPU (computer's graphic card) in hand luggage?

I need new GPU for my computer and must buy it from Finland. I am travelling with AirBaltics from Finland.  I would like to take the following GPU in my hand luggage because they break easily:    Can you get get GPU in hand luggage?


How to exit from bash script where root shell is on foreground process

I have a clean up script which cleans up memory  cleanup.sh  Script :  # root script starts here echo ".........running clean up script ..........."  /usr/local/packages/aime/ias/run_as_root "su -" free -t sync; echo 1 > sudo /proc/sys/vm/drop_caches free -t sync; echo 2 > sudo  /proc/sys/vm/drop_caches free -t sync; echo 3 > sudo /proc/sys/vm/drop_caches free -t swapoff -a && swapon -a echo "#####swapoff and swap on command ############" free -g exit # root script ends here free -g   script end  The script uses root and doing the stuff but could not able come out of root prompt  i tried exit 0, exit 1 and {exit} all   the process is comming to foreground , how to gabck to the shell where i started this script  running the script and script staying just as root  [sgongali@slc06wvd cronjob]$ ./cleanup.sh .........running clean up script ........... [root@slc06wvd ~]#    after i give exit manually what i get is below Note that swapoff -a && swapon -a is not working as part of script but its working manually  [root@slc06wvd ~]# exit logout              total       used       free     shared    buffers     cached Mem:      15037256   12776036    2261220     793448     382132    3357904 -/+ buffers/cache:    9036000    6001256 Swap:     15826924          0   15826924 Total:    30864180   12776036   18088144              total       used       free     shared    buffers     cached Mem:      15037256   12776036    2261220     793448     382140    3357896 -/+ buffers/cache:    9036000    6001256 Swap:     15826924          0   15826924 Total:    30864180   12776036   18088144              total       used       free     shared    buffers     cached Mem:      15037256   12776036    2261220     793448     382160    3357876 -/+ buffers/cache:    9036000    6001256 Swap:     15826924          0   15826924 Total:    30864180   12776036   18088144              total       used       free     shared    buffers     cached Mem:      15037256   12776104    2261152     793448     382164    3357872 -/+ buffers/cache:    9036068    6001188 Swap:     15826924          0   15826924 Total:    30864180   12776104   18088076 ./cleanup.sh: line 14: swapoff: command not found #####swapoff and swap on command ############              total       used       free     shared    buffers     cached Mem:            14         12          2          0          0          3 -/+ buffers/cache:          8          5 Swap:           15          0         15 [sgongali@slc06wvd cronjob]$


If you have two mirrors facing each other and you introduce a light source into the reflections and you take the light source away, would it immediately go away for all reflections in the "tunnel" of reflections?


This problem was inspired by this question.  $\sqrt [ 3 ]{ a(\frac { a+b }{ 2 } )(\frac { a+b+c }{ 3 } ) } \ge \frac { a+\sqrt { ab } +\sqrt [ 3 ]{ abc }  }{ 3 } $  The above can be proved using Hölder's inequality.   $\sqrt [ 3 ]{ a(\frac { a+b }{ 2 } )(\frac { a+b+c }{ 3 } ) } =\sqrt [ 3 ]{ (\frac { a }{ 3 } +\frac { a }{ 3 } +\frac { a }{ 3 } )(\frac { a }{ 3 } +\frac { a+b }{ 6 } +\frac { b }{ 3 } )(\frac { a+b+c }{ 3 } ) } \ge \sqrt [ 3 ]{ (\frac { a }{ 3 } +\frac { a }{ 3 } +\frac { a }{ 3 } )(\frac { a }{ 3 } +\frac { \sqrt { ab }  }{ 3 } +\frac { b }{ 3 } )(\frac { a }{ 3 } +\frac { b }{ 3 } +\frac { c }{ 3 } ) } (\because \text{AM-GM})\\ \ge \frac { a+\sqrt { ab } +\sqrt [ 3 ]{ abc }  }{ 3 } (\because \text{Holder's inequality)}$  However, I had trouble generalizing this inequality to   $\sqrt [ n ]{ \prod _{ i=1 }^{ n }{ { A }_{ i } }  } \ge \frac { \sum _{ i=1 }^{ n }{ { G }_{ i } }  }{ n } $  when ${ A }_{ i }=\frac { \sum _{ j=1 }^{ i }{ { a }_{ i } }  }{ i } $  and ${ G }_{ i }=\sqrt [ i ]{ \prod _{ j=1 }^{ i }{ { a }_{ i } }  } $ as I could not split the fractions as I did above.


Topological proof to show a complement set of a set is polygonally connected

I started learning topology recently, so I'm very new to this.    The question is as follows:     Given the set $A = \{ (x,y)\;;\;x, y\in\mathbb{Q} \}=\mathbb{Q}^2$, show that the complement set $A^c=\mathbb{R}^2\setminus A$ is polygonally connected.   As an attempt on this question, I plan to show that the set $A^c$ is connected, thus using a theorem, I can say $A^c$ is polygonally connected.  But here is the part that I got confused: By definition, the set $A^c$ is connected iff it cannot be written as the union of $2$ nonempty separated sets.    In this case, I believe $A^c$ is the set of all $(x,y)$ where $x,y$ belong to $\mathbb R-  \mathbb Q$.  But how can I express the fact that $A^c$ is not the union of $2$ nonempty separated sets ?   Based on my knowledge, I know both sets $\mathbb Q$  and $\mathbb R-\mathbb Q$ are dense, but how is this helpful to solving this problem?  I think a reason is because for any collection of $(x,y)$ where $x,y $are in $\mathbb Q$, I can always find a point in $\mathbb R-  \mathbb Q$ which is a boundary point of that certain collection.  But is my thought ok ?  Would someone please help me on this?  I'm kinda lost >_< Thanks ^^


What is the analytic continuation of the Riemann Zeta Function

I am told that when computing the zeroes one does not use the normal definition of the rieman zeta function but an altogether different one that obeys the same functional relation. What is this other function that they use explicitly given?  Also if I were to take one of these non trivial zeroes and plug it into the original definition would my answer tend towards zero as I evaluate the series?


How do I generate a pivoted CROSS JOIN where the resulting table definition is unknown?

Given two tables with an undefined row count with a name and value, how would I display a pivoted CROSS JOIN of a function over their values.  CREATE TEMP TABLE foo AS SELECT x::text AS name, x::int FROM generate_series(1,10) AS t(x);  CREATE TEMP TABLE bar AS SELECT x::text AS name, x::int FROM generate_series(1,5) AS t(x);   For example, if that function were multiplication, how would I generate a (multiplication) table like the one below,    All of those (arg1,arg2,result) rows can be generated with   SELECT foo.name AS arg1, bar.name AS arg2, foo.x*bar.x AS result FROM foo CROSS JOIN bar;    So this is only a question of presentation, I would like this to also work with a custom name -- a name that is not simply the argument CASTed to text but set in the table,  CREATE TEMP TABLE foo AS SELECT chr(x+64) AS name, x::int FROM generate_series(1,10) AS t(x);  CREATE TEMP TABLE bar AS SELECT chr(x+72) AS name, x::int FROM generate_series(1,5) AS t(x);   I think this would be easily do-able with a CROSSTAB capable of a dynamic return-type.  SELECT * FROM crosstab(   '     SELECT foo.x AS arg1, bar.x AS arg2, foo.x*bar.x     FROM foo     CROSS JOIN bar   ', 'SELECT DISTINCT name FROM bar' ) AS **MAGIC**   But, without the **MAGIC**, I get   ERROR:  a column definition list is required for functions returning "record" LINE 1: SELECT * FROM crosstab(    For reference, using the above examples with names this is something more like what tablefunc's crosstab() wants.  SELECT * FROM crosstab(   '     SELECT foo.x AS arg1, bar.x AS arg2, foo.x*bar.x     FROM foo     CROSS JOIN bar   ' ) AS t(row int, i int, j int, k int, l int, m int);   But, now we're back to making assumptions about the content and size of the bar table in our example. So if,   The tables are of undefined length, Then the cross-join represents a cube of undefined dimension (because of above), The catagory-names (cross-tab parlance) are in the table   What's the best we can do in PostgreSQL without a "column definition list" to generate that kind of presentation?


I recently tried out the beta of Big Sur on a separate APFS container. I don't need it anymore so I deleted the container. There is now one more container left called "Update". Does anyone know if this container belongs to Big Sur? Can I just delete it as well? EDIT This is the output of diskutil list: /dev/disk0 (internal, physical):    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:      GUID_partition_scheme                        *500.3 GB   disk0    1:                        EFI EFI                     209.7 MB   disk0s1    2:                 Apple_APFS Container disk1         500.1 GB   disk0s2  /dev/disk1 (synthesized):    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:      APFS Container Scheme -                      +500.1 GB   disk1                                  Physical Store disk0s2    1:                APFS Volume Macintosh HD - Daten    312.2 GB   disk1s1    2:                APFS Volume Preboot                 91.4 MB    disk1s2    3:                APFS Volume Recovery                528.8 MB   disk1s3    4:                APFS Volume VM                      1.1 GB     disk1s4    5:                APFS Volume Macintosh HD            11.2 GB    disk1s5    6:                APFS Volume                         14.0 GB    disk1s7    7:                APFS Volume Update                  819.9 MB   disk1s8


How to install codec on live Ubuntu 16.04 LTS?  If I try run sudo apt-get update, I get this message:     comunicate "** (appstreamcli:6785): CRITICAL **: Error while moving old database out of the way.   "


The disk my server is on was full and Apache couldn't create logfiles anymore. I cleaned the disk and it has enough free disk space now, but still no logfiles are created. I tought to try restarting Apache (hoping that the issue would be solved by that, if somebody has some other bright idea, be welcome...), but that gave the following error messsage:  # /usr/local/apache2/bin/httpd -k restart [Tue Jun 06 11:58:33 2017] [warn] NameVirtualHost *:443 has no VirtualHosts httpd not running, trying to start (98)Address already in use: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down Unable to open logs   The "unable to open logs" is the reason I wanted to restart Apache, but it still isn't working... anybody have an idea what I could do?  Trying to solve the "make_sock: could not bind to address 0.0.0.0:80,", I tried   # /usr/local/apache2/bin/httpd -k stop   This gives me this message ...   [Tue Jun 06 14:00:14 2017] [warn] NameVirtualHost *:443 has no VirtualHosts httpd (no pid file) not running   but when I try   # ps aux | grep apache   I get ...   apache1267  0.2  0.0  31816  7548 ?S13:53   0:01 /usr/local/apache2/bin/httpd -k start apache1535  0.1  0.0  31520  7320 ?S13:54   0:00 /usr/local/apache2/bin/httpd -k start apache1541  0.1  0.0  30224  6016 ?S13:54   0:00 /usr/local/apache2/bin/httpd -k start apache1928  0.1  0.0  30744  6440 ?S13:56   0:00 /usr/local/apache2/bin/httpd -k start apache2075  0.2  0.0  31268  6732 ?S13:57   0:00 /usr/local/apache2/bin/httpd -k start apache2508  0.2  0.0  30624  6284 ?S14:00   0:00 /usr/local/apache2/bin/httpd -k start apache2693  0.3  0.0  30236  5724 ?S14:01   0:00 /usr/local/apache2/bin/httpd -k start apache2718  0.0  0.0  30368  5788 ?S14:01   0:00 /usr/local/apache2/bin/httpd -k start apache2722  0.0  0.0  30068  4968 ?S14:01   0:00 /usr/local/apache2/bin/httpd -k start apache2754  0.2  0.0  31272  6516 ?S14:02   0:00 /usr/local/apache2/bin/httpd -k start apache2780  0.1  0.0  30232  5688 ?S14:02   0:00 /usr/local/apache2/bin/httpd -k start apache2808  0.2  0.0  30496  6016 ?S14:02   0:00 /usr/local/apache2/bin/httpd -k start apache2903  0.0  0.0  29928  4748 ?S14:02   0:00 /usr/local/apache2/bin/httpd -k start apache2912  0.0  0.0  29792  3944 ?S14:03   0:00 /usr/local/apache2/bin/httpd -k start apache2915  0.0  0.0  29792  3772 ?S14:03   0:00 /usr/local/apache2/bin/httpd -k start apache2916  0.0  0.0  29792  3772 ?S14:03   0:00 /usr/local/apache2/bin/httpd -k start root  2921  0.0  0.0   3348   844 pts/0S+   14:03   0:00 grep apache root 18281  0.0  0.0  29792  5000 ?Ss   May29   0:21 /usr/local/apache2/bin/httpd -k start


Why is Java 10 installed in /usr/lib/jvm/java-11-openjdk-amd64?

I uninstalled all versions of java. I then installed java using  sudo apt install default-jre default-jdk  I then looked to see which java is installed and what version it is. Here is the result I got:  joshua @Joshua-PC ~ $ readlink -f `which java`                                                                                /usr/lib/jvm/java-11-openjdk-amd64/bin/java  joshua @Joshua-PC ~ $ java --version                                                                                openjdk 10.0.2 2018-07-17 OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.3) OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.3, mixed mode)   `  Why is java version 10 in the java 11 directory?


Check whether values are unique in a column or not

How can I check if a value in a cell of a specific column is unique in the respective column or not.  e.g. I have a column called OBJECTID. Some of the ID's are unique whereas others exist twice.   I would like to create a new column which indicates whether a value is unique or not.


I'm working through an abstract algebra book that mentioned something but made me want to understand something semi unrelated that I wasn't sure of. If we have a prime number $p$ we know that by Wilson's theorem that $(p-1)! \equiv -1$ mod $p$. Is there a way to apply this and make it work for any $n \in \mathbb{N}$ such that $n$ is less than $p$? For instance is there a way to get a "formula" for $(p-n)!$ Would $(p-n)! \equiv - n$ mod $p$ work?


Download folders and subfolders from document libraries: bulk download

I have multiple folders and sub folders in a SharePoint document library.   How to download multiple folders and subfolders from this library at once?


What is the simplest organism that was observed to learn: change its behavior permanently in response to some event/stimuli in a way that this change persists even if the event does not happen again?


Is there a single word for the quality of doing good works for others without any selfishness?

Can anyone give the exact single word for the feeling/quality of doing good works for others without having any selfishness?


I have a simple algorithm to add a node in a sorted LinkedList in Java. The issue is with insertBefore method. When the call returns to the calling method, the reference (node) is not updated with pointing to the new node. Java is call by reference and should update the underlying object value, according to my understanding. Any help appreciated.  Below is the code:  public MyListNode<Integer> findAndInsert(MyListNode<Integer> node, int nbr) {      MyListNode<Integer> head = node;     MyListNode<Integer> tail = null;      boolean inserted = false;      //Sample Input: 2, 3, 5, 7, 9;  1     //Sample Output: 1, 2, 3, 5, 7, 9      if(nbr <= node.data)     {         insertBefore(node, nbr);         inserted = true;     }     else     {         while(node != null && node.next != null)         {             if( nbr <= node.next.data )             {                  insertAfter(node, nbr);                 inserted = true;                 break;             }              if(node.next.next == null)             {                 tail = node.next;             }              node = node.next;         }     }      if(!inserted)     {         insertAfter(tail, nbr);     }     return head; }  public void insertAfter(MyListNode<Integer> node, int i) {     MyListNode<Integer> n = new MyListNode<Integer>(new Integer(i));      n.next = node.next;     node.next = n; }  public void insertBefore(MyListNode<Integer> head, int i) {     MyListNode<Integer> newNode = new MyListNode<Integer>(new Integer(i));       newNode.next = head;     head = newNode; }


Looking for a phrase: a needlessly overcomplicated method of accomplishing a simple task

In my language, there is an expression for this - you can touch the tip of your nose normally, or you can move your hand behind your neck, across it, then touch the tip of the nose from the opposite side. I can't translate this to a concise and acceptable phrase/idiom, and the descriptive version loses its sheen in the verbose explanation.  So what's a good phrase in English for this? I've heard of some close versions like:   three right turns to make a left two steps forward, one step back (although this is usually in the context of progress)   But they don't quite get the same feeling across.


What creating bootloop when flashing TWRP?

I follow this XDA tutorial to . However, after flashing TWRP via Odin, the phone only boots into recovery, not system. Even factory reset or  cannot help. I have to reflash its . This erases TWRP and replace with the stock recovery. This is what the tutorial says, which I follow exactly:  Flash with ODIN in the AP slot. Put your device in DOWNLOAD mode. Uncheck Auto reboot. Load the respective file below into the AP slot and hit start. After flashing and ODIN reports PASS immediately reboot to recovery by holding POWER + HOME + VOL DOWN. As soon as the screen goes blank change to VOL UP whilst still holding POWER + HOME. You should now see TWRP recovery.  Yes I see TWRP recovery, but now the system cannot be booted.


I wrote a small software in Python, and I'd like to keep it secure. Of course I know it's the wrong language, but at the moment I cannot rewrite it. The small program will run under a linux box. Eventually I can turn to windows if it's easier to achieve my goal. I'd like to avoid users to unplug the disk and connect to another PC to download the file. In this case I think a crypted partition could be my case, with TPM, or maybe a secure usb key? If a user can have access to the pc, is there a way to let him not read the py files? Like encrypt them but still able to run it, as example with a usb secure key?  thank you   UPDATE/CLOSE I write an update even if the case is closed because it could be useful for someone, I'm using Python 2.7 with Pyglet framework, and with pyinstaller under linux it worked like a charm


I stumbled upon this question in my course, and I am out of ideas. Let $f$ be a periodic function $$f(x)=f(x+l), \qquad l>0$$  Prove that if it is not constant, then $\lim_{x\to 0}f\left(\frac1x\right)$ does not exist.  I don't understand why it's true, let alone how to prove it.


I'm trying to make sense of the  tag. It has no description, and the questions tagged with it are all over the place - filtering rows in SQL, limiting access to certain devices/activities, defining the allowed input values for programs, etc., etc.  With such a wide range of topics, does this tag make sense to anyone, or should it just need to be burniated?


I am trying to use a method for an object in an array in an enhanced for loop but it gives me an error message that says null. Here is my code: Pet[] pets = new Pet[10];  pets[0] = new Pet("Buddy", 2); pets[1] = new Pet("Cocoa", 2); pets[2] = new Pet("Caramel", 1); pets[3] = new Pet("Oreo", 1);  for (Pet p : pets) {   p.feed(); }


Bash - How do I loop through sub directories and execute this command

Well, Before I decided to post this I have tried all the solutions provided here that are related to my issue. And I know it's a simple but this is my first time ever dealing with Bash .. so please bear with me a little  I have this Script      FILES=*.html for f in $FILES do    # extension="${f##*.}"   filename="${f%.*}"   echo "Converting $f to $filename.md"   `pandoc $f -t markdown -o $filename.md`   rm $f done   This script was created to convert a directory full of Html files into markdown equivalents. It uses Pandoc to do the conversion.  The issue is this script will convert the file in the same exact folder only, and I want to convert all the files in subfolders like this:  Folder1/Folder2/folder3/index.html   So any ideas on how I could do this?


Why is my render camera always teleporting to a top view?

Whenever I add a camera to my scene and set it as main camera with ctrl+num0 and press render, the camera 'teleports' to a strange top view where no camera is placed. After that that strange camera automatically becomes my main camera. I am stuck in this endless loop of setting the actual camera as main camera and blender switching it to a nonexistent camera. Does anybody have a solution for me or some tips? The first image I added gives a clear view of the scene with the main camera selected. The second picture shows the wrong camera view it switches to. Thanks in advance, Lucas


I want to know if it is possible to update to Xubuntu 20.04 since I can't find a 32-bit version. If I update through the terminal with sudo apt update && sudo apt -y dist-upgrade  will the system break? Thank you!


There's a weird thing happening with my Windows application. I have created a Sharepoint utility to automate the creation of content-types and site-columns. At a point where I try to get my available fields, I get this error:     An unhandled exception of type 'Microsoft.SharePoint.Client.ServerException' occurred in Microsoft.SharePoint.Client.Runtime.dll   Additional information: Requested value 'CheckBoxes' was not found.   It is throwing an exception at:  ClientContext clientContxt = new ClientContext(clientContext.Url);         clientContext.Credentials = clientContext.Credentials;         Web web = clientContext.Web;          clientContext.Load(web, w => w.AvailableFields);         clientContext.ExecuteQuery(); //**exception thrown here**   Kindly please suggest what is wrong here?


python case sensitive disable and get eual string

def worker(queue):     while True:         if not queue.empty():             words = 'BananA'             words1 = 'nut'             words2 = 'KreMA'             words3 = 'KIVI'             words4 = 'TesT'             process(data, words, words1, words2, words3, words4)  def process(data, words, words1, words2, words3, words4):     if (search != words):         print("Words Not Found")     if (words in search or words1 in search or words2 in search or words3 in search or words4 in search):         print("Words Found  : " + str(Words) + "\n")         file = open("finded.txt","a")         file.write("Words Founds "+ str(words)         file.close()   but, if change the line if "banana"  to "Banana"  the code not work, I need Banana or BANANA or BaNaNa get equal, and get true,


What is the best way to monitor a production server?

We are running two production servers with Apache 2 and MySQL. I am looking for a reliable way of monitoring our load, stability and uptime.  I have come across , but are there better alternatives?


I have purchased a theme from envato and the theme came with a bunch of different demos. I am trying to use the "app landing" demo. It has already been installed but I am not able to make it my main page. Can someone help?  Thank you! Kelvin


Can a dementor decide which people around it will be affected by its magic?

Quoting from  and : From a :  Samantha: Was snape the only death eater who could produce a full patronus J.K. Rowling: Yes, because a Patronus is used against things that the Death Eaters generally generate, or fight alongside. They would not need Patronuses.  I always had the impression that just the presence of a dementor should have an effect on any human around, DE or otherwise. However, this quote makes it sound like DE's are exempt from the effect of the dementors. However, from Sirius's description in book 3, we know every prisoner in Azkaban was affected by dementors, which can further be corroborated by the fact of how much Barty Crouch, Jr. was scared of being thrown into Azkaban. Moreover, if the dementors didn't affect the DE's at all, throwing them in Azkaban wouldn't be much of a punishment either. So, Can dementors decide who to affect or not?


How to correct parse query string in C# if value contains ampersand?

I need parse query string: ?artist=singer1 & singer2&song=name song  Static method HttpUtility.ParseQueryString doesn't work the way I want if value contains ampersand like "singer1 & singer2".  For example:   string qs = "?artist=singer1 & singer2&song=name song";  NameValueCollection query = HttpUtility.ParseQueryString(qs);   Result is:        artist = singer1   null = singer2   song = name song      I would like result  artist = singer 1 & singer2 song = name song   Any idea?


How is the holodeck still rendering during the Voyager power drain?

In the Star Trek: Voyager episode "Night" (S05 E01), Voyager suffers a ship-wide total power drain.  How is the holodeck still rendering Tom Paris' program, albeit in darkness? He turns on a program-driven torch and you can see the screen.


Can you command someone under the Imperio to use the Imperio?


Settings API - Undefined Index when unchecking checkbox

I know this may be a duplicate however I haven't been able to make sense of previous questions.  I have a checkbox on a settings page. Everything is okay on the first load of the page, if I check the box and save all is fine. If I then uncheck i get the following error:     Notice: Undefined index: dat_checkbox_field_0 in .../wp-content/plugins/divi-auto-testimonials/admin/dat-options.php on line 49   value='1'>   The function:  function dat_checkbox_field_0_render(  ) {       $options = get_option( 'dat_settings' );     ?>     <input type='checkbox' name='dat_settings[dat_checkbox_field_0]' <?php checked( $options['dat_checkbox_field_0'], 1 ); ?> value='1'>     <?php  }   Line 49 is the input html.  I also get the same error for this code:  $options = get_option( 'dat_settings' ); if( $options['dat_checkbox_field_0'] != '1' ) {  include_once "admin/notification.php"; }   From what I understand I need to set the value as null I think but I am not entirely sure if that is correct and if so how.


I have used Matlab prettifier package with \lstinputlistings{file.m} command but its not working. Is there another way to import your MATLAB Code to the LATEX?


Show the determinant of a matrix is divisible by 17 without evaluating the determinant

Use the fact that 11322, 13209, 29189, 56661, and 15096 are all divisible by 17 to show that   $$\begin{vmatrix}  1&1&2&5&1\\ 1&3&9&6&5\\ 3&2&1&6&0\\ 2&0&8&6&9\\ 2&9&9&1&6 \end{vmatrix}$$   is divisible by 17 without directly evaluating the determinant.


Inner div text center inside a div block

I am working on website index page and my code is working fine on my pc. But on 25% inner div moving down . Here is snapshot:    and on 25% screen:    want it on the center and even i use position: fixed but nothing works. However i change structure but nothing work.    .txg{      position: absolute;         top: 40%;         left: 50%;         -moz-transform: translateX(-50%) translateY(-50%);         -webkit-transform: translateX(-50%) translateY(-50%);         transform: translateX(-50%) translateY(-50%);     }     .homelogo {      text-align: center;      line-height: 1em;      font-family: helvetica, arial, sans-serif;      font-weight: bold;      background: linear-gradient(to right, #7db9e8 50%,#1e5799 50%);      -webkit-background-clip: text;      -webkit-text-fill-color: transparent;      font-size: 50px;     }     .teg{      position: absolute;         top: 50%;         left: 48%;         -moz-transform: translateX(-50%) translateY(-48%);         -webkit-transform: translateX(-50%) translateY(-48%);         transform: translateX(-50%) translateY(-48%);     }     .teg ul{      list-style: none;     }     .teg li{      display: inline-block;      background-color: #07ABD8;      padding:15px;      border-radius: 8px;      font-size: 15px;      text-transform: uppercase;      font-family: helvetica, arial, sans-serif;     }     .teg li a{      text-decoration: none;      color: white;     }
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I have a series given below and I have to check if it converges or diverges. $$\sum_{2}^\infty    \frac{1}{\ln(n)^{\ln(n)}}$$ I decided for a comprasion test. Firstly, I converted  denominator so that; $\ln(n)^{\ln(n)}=n^{\ln(\ln(n))} $ (quick trick using properties of "e" number.) Next step - comparison with using inequalities:$$ \frac{1}{n^2}\geqslant \frac{1}{n^{\ln(\ln(n))}} \Rightarrow  n^2 \leqslant n^{ln(ln(n))} $$ But it holds only for $n\geqslant e^{e^2}$. Because I know that $\sum_{1}^\infty    \frac{1}{n^2}$ converges I did the following : $$\sum_{2}^\infty    \frac{1}{n^{\ln(\ln(n))}} =\sum_ {2}^{\lfloor e^{e^2}\rfloor}    \frac{1}{n^{\ln(\ln(n))}}(=A)+\sum_{\lceil e^{e^2}\rceil}^\infty   \frac{1}{n^{\ln(\ln(n))}}(=B)$$ I called first part as A, and second part as B. I assumed that $-\infty \lt A\lt \infty \Rightarrow $ convergence. That is because we sum up to the finite number = $\lfloor e^{e^2}\rfloor$. Since our inequality holds for $n\geqslant e^{e^2}$ I did a comprasion test only for B. $$ \frac{1}{n^2}\geqslant \frac{1}{n^{\ln(\ln(n))}} \Rightarrow \sum_{\lceil e^{e^2}\rceil}^\infty    \frac{1}{n^2} \geqslant \sum_{\lceil e^{e^2}\rceil}^\infty    \frac{1}{n^{\ln(\ln(n))}}=B $$ $\sum_{\lceil e^{e^2}\rceil}^\infty    \frac{1}{n^2}$ converges and it is greater than series "B" implies that B converges as WELL. Is my thinking correct? Have I done any mistakes ?


Two mutually untrusted parties want to exchange data: how to ensure each one gets the data it needs?

I am trying to come up with what could maybe be a novel algorithm for an application I am writing. Client A has a file fA. Client B has file fB. Each party is untrustworthy and will try to rip off the other party. Client A wants the fB and client B wants fA.  How can I make an algorithm were it is not possible for them to screw the other player.  For example:     A encrypts fA and send the file to B.     B encrypts fB and sends it to A.  Now, both A and B have an encrypted version of the file they want.  How can they both share the decryption key at the same time... or what?   Is this even possible? This is breaking my mind.  Since each client will try to rip the other party, Client A cannot send the file fA to client B and expect client B to send back its file. If client A sends it first "with no guarantees", client B will simply run off with the file.  In real life a person holds the pot in one hand, the other holds the cash in the other. They both trade each hand at the same time. The guy with the cash now ends up with the pot and vice versa. How can I do something similar with computer bits. (client A and B are on a network at different locations).  EDIT: Please note that each party has a hash of the file they are supposed to get. Therefore, the parties cannot send a junk file to the other guy whit-out him knowing. A trusted third party will provide the hash.


I have difficulty understanding the meaning of the Principal Components (PC) -    On one hand, PC are computed by finding loading vectors that maximize the variance, but on the other hand I read another interpretation that says PC are the closes to the n-observations. It seems to me like there is a contradiction, how are they closest if they have the highest variance?.. In general, when do we know to stop at the first PC and not go for the second one?    Thanks


Matrix mechanics for those with wave mechanics background

Just curious:  Is there any book or resource that teaches  (quantum mechanics) only without wave mechanics stuff - meaning that the book assumes wave mechanics background.


I'm given that $f:\mathbb{R} \to \mathbb{R}$ is twice differentiable and $f(0) = f'(0) =1$.  Assuming that $f''(x) > f(x)$ everywhere show that $f(x) > 0$ for all $x$.  I know that $f$ and $f’$  are continuous ($f’’$ exists). Since $f(0) =  f’(0)= 1$ there is some $\delta > 0$ where $f(x), f’(x) > 0$ for $-\delta \leq x \leq \delta$. I tried using the second-order Taylor approximation to extend the interval but I cannot see how to show $f(x) > 0$ for all $x < -\delta$.


"It is the category where most of the processed data falls into" - is it correct?

Is the following sentence correct? I have some doubts about "category where ... fall into" phrase.     It is the category where most of the processed data falls into


Can only write as root although user seems to have full permissions

I am having trouble writing to a samba share from a linux client (a Windows client can read and write just fine). According to ls -la run from the linux client, I should have full permissions:  james@Q35-ICH9:~$ ls -la /mnt/ total 8 drwxr-xr-x  3 root  root  4096 Feb 25 09:38 . drwxr-xr-x 24 root  root  4096 Feb 25 04:39 .. drwxrwxrwx 61 james james    0 Feb 26 05:39 cloudshare  james@Q35-ICH9:~$ getfacl  /mnt/cloudshare/ getfacl: Removing leading '/' from absolute path names # file: mnt/cloudshare/ # owner: james # group: james user::rwx group::rwx other::rwx   but:  james@Q35-ICH9:~$ touch  /mnt/cloudshare/test touch: cannot touch '/mnt/cloudshare/test': Permission denied   But if I use sudo, I can touch:  james@Q35-ICH9:~$ sudo touch  /mnt/cloudshare/test   The user also has full access to the parent folder:  james@Q35-ICH9:~$ ls -la /mnt/ total 8 drwxrwxrwx  3 james james 4096 Feb 25 09:38 . drwxr-xr-x 24 root  root  4096 Feb 25 04:39 .. drwxrwxrwx 61 james james    0 Feb 26 07:42 cloudshare   I am confused as to why I need to be root to write to cloudshare even though 'james' should have full permissions (as far as I can see).


Would it be possible to install the T3i software on my T5 (1200D)? Both cameras have the same Digic-4 CPU. The reason I'm asking this is that the T3i have some features for video my T5 doesn't have.


Why is a parameter in a dynamically written LINQ operation causing error

I need to add a dynamic number of Join operations to a LINQ expression. The number is the size of the DemHeaderIDs array. The Joins include a Where clause with a parameter taken from the DemoHeaderIDs array. Using DemoHeaderIDs[0] in the first set works fine.  But when trying to use a DemoHeaderID[i] in a loop I get the error message below.  When I use a hard coded integer instead of DemoHeadersID[i], the code runs fine and the result is correct.  My Code:  private void DoSomething(int[] DemoHeaderIDs, OVContext _context) {   //first set of joins     var q = from oh in _context.OrgHierarchy             join odd in _context.OrgDemoData on oh.Identifier equals odd.Identifier             join dh in _context.DemoHeader.Where(h => h.DemoHeaderId == DemoHeaderIDs[0]) on odd.Demoheaderid equals dh.DemoHeaderId             select new             {                 Name = odd.Demovalue,                 Parent = "All",                 Identifier = oh.Identifier             };      for (int i = 1; i < DemoHeaderIDs.Count(); i += 1)     {   //dynamic joins         q = from qObj in q             join odd in _context.OrgDemoData on qObj.Identifier equals odd.Identifier             join dh in _context.DemoHeader.Where(h => h.DemoHeaderId == DemoHeaderIDs[i]) on odd.Demoheaderid equals dh.DemoHeaderId             select new             {                 Name = odd.Demovalue,                 Parent = qObj.Name,                 Identifier = qObj.Identifier             };     }      var ql = q.ToList();   The Error Message:     System.IndexOutOfRangeException: Index was outside the bounds of the   array.    at lambda_method(Closure )    at   Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.ParameterExtractingExpressionVisitor.Evaluate(Expression   expression, String& parameterName)   Adding EnableSensitiveDataLogging() to the DbContext configuration did not add information to the message.  I'm using EntityFramework.Core 2.2.


Regex: Do not replace any char or digit from any language

I used this regex to clear string from any non-alphanumeric characters   /[^0-9a-z]/gi   However, in my program there some strings with Arabic, Hebrew, Chinese and Dutch chars that are cleaned by this regex. For future support I would like to use regex that will not clean any alphanumeric chars on any language. Is it possible to create such one?


Repository error received during an upgrade

E: Repository 'http://ppa.launchpad.net/webupd8team/java/ubuntu bionic InRelease' changed its 'Label' value from 'Oracle Java (JDK) 8 Installer PPA' to 'Oracle Java (JDK) 8 Installer PPA (DISCONTINUED)' N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.   i read manpage but did not fully understand what i was to do so i did nothing...how do i resolve this issue???  Thank You


i need comma in between my number  eg- 1000 --> 1,000  i m attaching the controller and vf page for this  public List<BarData> getOpportunityTarget(){     Integer CurrentMonth = Date.Today().Month();     Decimal total = 0.0;      TargetList = new List<BarData>();     if(MonthlyTargetMap.get(currentMonth) != null){         if(OpportunityList.size()>0){                for(Opportunity objOpportunity : OpportunityList){                 if(objOpportunity.StageName == 'Approved' && objOpportunity.Amount != null && objOpportunity.closeDate.Month() == CurrentMonth){                     total += objOpportunity.Amount;                 }             }             TargetList.add(new BarData('Closed',total.setScale(0)));                     TargetList.add(new BarData('Target',MonthlyTargetMap.get(currentMonth).setScale(0)));                     }else{             TargetList.add(new BarData('Closed',0));                     TargetList.add(new BarData('Target',MonthlyTargetMap.get(currentMonth).setScale(0)));                     }     }                                         return TargetList;          Vf Page

Closed v/s Running Target

          <apex:chart height="300" width="400" data="{!OpportunityTarget}">             <apex:axis type="Numeric" position="left" fields="data" grid="true" minimum="0" />             <apex:axis type="Category" position="bottom" fields="name">                 <apex:chartLabel rotate="315" font="bold 13px Helvetica"/>             </apex:axis>             <apex:barSeries orientation="vertical" axis="left" xField="name" yField="data" colorSet="#99ccff">                 <apex:chartTips height="20" width="150" />                 <apex:chartLabel field="data" display="outside" orientation="horizontal" font="bold 12px Helvetica" />                                                 </apex:barSeries>         </apex:chart>


How to fix Spanish-Style Milkfish that became Too Salty

My wife made spanish-style milkfish, when I tasted it during the night it was alright, but when I tasted it next day for breakfast it has become too salty! I searched for recipes and saw that you're supposed to rinse the fish in running water after soaking it in brine for 1 hour but my wife says the recipe she found did not say that the fish should be rinsed. Is there any way to still fix this? The fish is already too soft to be rinsed and Im not sure vinegar or lemon juice would get through the olive oil. Thanks in advance.


Trying to figure out size of a linked list null pointer error

For the below code, I would like to know why the size of the linked list keeps giving me a null pointer exeption and why my pushEnd method to push a new node at the end doesnt work, it add an element after a few nodes and gets rid of rest.   class Node { int data; Node next; Node(int data){     this.data = data; }   }  public class LinkedList { Node head;    /* Inserts a new Node at front of the list. */ public Node push(int data)  {      Node newNode = new Node(data);      newNode.next = head;      return head = newNode;  }  public Node pushEnd(int data) {     Node newNode = new Node(data);     if (head == null) {         head = newNode;     }      newNode.next = null;      while(head != null) {         head = head.next;         head.next = newNode;         return newNode;         }     return head; }  public int getSize() {     int size = 0;     while(this.head != null) {         size++;         head = head.next;     }     return size; }   public void printList() {     while (this.head !=null) {         System.out.print(head.data + "-->");         head = head.next;     }            System.out.println(head); }   }  public class Tester {   public static void main(String[] args) {      LinkedList ll = new LinkedList();      ll.push(35);     ll.push(100);     ll.push(14);     ll.push(44);     ll.push(10);     ll.push(8);       System.out.println("Created Linked list is:");      ll.printList();         System.out.println(ll.getSize());  }  }   I want to figure out the size of the linked list and be able to add nodes at the end.


Ways to turn of a repeating_cb set to tp you away from it

I just added a repeating command block to an adventure map(1.15.2) I've been working on for awhile. It's purpose was to detect a falling player and then to tp them approximately 300 blocks away. I got distracted and ended up turning it on with a command along the lines of "execute if @p at @p run tp 20 70 200" This causes me to tp to the location whenever the block region containing the command block is loaded. My question is has anyone got any ideas of possible ways to solve this? I know the general location but cannot use the fill function as the blocks aren't loaded. And states this when executed Gamerule commandblockoutput false doesn't help And it registers me in spectator mode and still tp back.


a command to list all packagas installed on the system and their installed files, how?

I am using Ubuntu 14.04 LTS, Trusty. I want to execute a command to list all the installed packages of the system and for each packages name , it should list all the files that package has installed on the system. how I can do that?


Neron-Severi group as the image of first Chern class

Let $X$ be a smooth projective variety over $\mathbb{C}$, then the Neron-Severi group $NS(X)$ of $X$ is defined to be the Picard group of $X$ modulo algebraically equivalent relations.   On the other hand, by the exponential sequence, there is a first Chern class map  $$c_1: {\rm Pic}(X) \to H^2(X, \mathbb{Z}).$$ It is claimed that the image of $c_1$ coincides with $NS(X)$.   I want to know why this is true. Any suggestion or reference is greatly welcome!


What is the best workaround for the WCF client `using` block issue?

I like instantiating my WCF service clients within a using block as it's pretty much the standard way to use resources that implement IDisposable: using (var client = new SomeWCFServiceClient())  {     //Do something with the client  }  But, as noted in , wrapping a WCF client in a using block could mask any errors that result in the client being left in a faulted state (like a timeout or communication problem). Long story short, when Dispose() is called, the client's Close() method fires, but throws an error because it's in a faulted state. The original exception is then masked by the second exception. Not good. The suggested workaround in the MSDN article is to completely avoid using a using block, and to instead instantiate your clients and use them something like this: try {     ...     client.Close(); } catch (CommunicationException e) {     ...     client.Abort(); } catch (TimeoutException e) {     ...     client.Abort(); } catch (Exception e) {     ...     client.Abort();     throw; }  Compared to the using block, I think that's ugly. And a lot of code to write each time you need a client. Luckily, I found a few other workarounds, such as this one on the (now defunct) IServiceOriented blog. You start with: public delegate void UseServiceDelegate<T>(T proxy);   public static class Service<T>  {      public static ChannelFactory<T> _channelFactory = new ChannelFactory<T>("");           public static void Use(UseServiceDelegate<T> codeBlock)      {          IClientChannel proxy = (IClientChannel)_channelFactory.CreateChannel();          bool success = false;          try          {              codeBlock((T)proxy);              proxy.Close();              success = true;          }          finally          {              if (!success)              {                  proxy.Abort();              }          }       }  }   Which then allows: Service<IOrderService>.Use(orderService =>  {      orderService.PlaceOrder(request);  });   That's not bad, but I don't think it's as expressive and easily understandable as the using block. The workaround I'm currently trying to use I first read about on . Basically, you override the client's Dispose() method wherever you use it. Something like: public partial class SomeWCFServiceClient : IDisposable {     void IDisposable.Dispose()      {         if (this.State == CommunicationState.Faulted)          {             this.Abort();         }          else          {             this.Close();         }     } }  This appears to be able to allow the using block again without the danger of masking a faulted state exception. So, are there any other gotchas I have to look out for using these workarounds? Has anybody come up with anything better?


Why are nuclear weapons rare in the Star Wars universe?

I am reading the book Darth Plagueis, and when an assassination attempt is made on him by use of a nuclear bomb, the book states that nuclear weapons are scarcely available.   I searched briefly but found nothing on this and wondered if an explanation is available. Why would nuclear weapons be rare in a universe with such advanced technology across the board?


Blocking youtube on Ubuntu using etc/hosts

I want to block Youtube using the hosts file. I managed to do this with Facebook and Instagram but with Youtube it is not working.  Here is my hosts file:  127.0.0.1   localhost 127.0.1.1   goncalo-X541UV  #The following lines are desirable for IPv6 capable hosts  ::1     ip6-localhost ip6-loopback   fe00::0 ip6-localnet   ff00::0 ip6-mcastprefix   ff02::1 ip6-allnodes    ff02::2 ip6-allrouters    127.0.0.1 216.58.210.174   127.0.0.1 youtube.com   127.0.0.1 www.youtube.com   127.0.0.1 www.facebook.com   127.0.0.1 www.instagram.com


I have test.csv,test1.csv,test2.csv...etc files. These files i am loading into custom table test through sql loader. in table test i have columns named seq_no,process_id apart from columns coimng from flat file mentioned above. i had created two sequence as mentioned below for the above mnetioned two columns.    CREATE SEQUENCE  test   MINVALUE 1   INCREMENT BY 1    START WITH 1   NOCACHE   NOORDER    NOCYCLE ;     and     CREATE SEQUENCE  test1    MINVALUE 1   INCREMENT BY 1   START WITH 1   NOCACHE          NOORDER    NOCYCLE ;     Now, seq_no will get populated depends on the no.of files getting loaded  E.G: if v have 5 files then seq_no would be 1,2,3,4,5 And process_id would be inside file how many "FDETL" records are ther that many E.G if v have file 1, FDETL=2 then seq_no=1,process_id=1,2     if v have file 2,FDETL=3 then seq_no=2,process_id=1,2,3. It is some thing like process_id should repeat/file. Now i am using test1.nextval So how can i reset the sequence test1 so that for every file process_id will repeat from 1 to count(FDETL) records?


How can I open a terminal in the desktop directory?

I am using Ubuntu 16.04 and Nautilus 3.14.3 (default version).  There is an open terminal context menu when right- clicking on the desktop. It opens the terminal with ~ as working directory, but I'd like it to open in ~/Desktop.  I think there was a dconf option to change this behavior, but I cannot find anything related under /org/gnome/nautilus.


Why is it that Complex Numbers are algebraically closed?

I find it curious that Complex Numbers give enough flexibility to be algebraically closed, where the reals, rational numbers do not.  For the reals it is easy to see that they cannot be used to solve equations like $x^2 + 1 =0$.  Geometrically, one can look at the number line as see that any $x$ squared yields a positive number which when added to one cannot get you back to zero.  In the complex case, however, we are working with the plane.  In this case exponents stretch and rotate any given $x$.  It is easy to therefore see in the particular circumstance that if $x=i$ that $x^2$ rotates it to $-1$ which when added to one yields the desired result (i.e. $0$).  So because the Complex Numbers are algebraically closed, I conclude that any polynomial equation with complex coefficients my be solved by choosing one or more $x$'s in the plane and rotating them and stretching them such that they will combine using the given coefficients to produce the RHS.    Question: Why is it that we do not need a larger space than the plane to solve Complex polynomial equations?  I have tried to find a sufficient answer through Google, but was not able.  I also searched M.SE and could not find a sufficient answer.  I am not a mathematician, so I am looking for an intuitive answer if possible.


How do I replace the default GRUB bootloader?

I have 2 distributions in my PC. Ubuntu and Linux Mint. Linux Mint was installed second, but I work mostly in Ubuntu.  Whenever I install new kernel in my ubuntu, I have to run update-grub from Linux-Mint to get it updated in Grub screen. Is there anyway to make the GRUB in my ubuntu as the one which loads the operating systems?


Stabilizing a gravel driveway with massive holes and steep inclination

I have inherited a 270 feet long driveway along a steep hill. It is part gravel/stone, and part concrete.  It is in very bad condition. Every winter, rain threatens to wash away parts of it. Driving up and down is very bad for the car, and deepens the damage depending on the skill of the driver.  The previous owner has applied some concrete, but only in a few select spots.  I guess the final fix for it is to have a professional pour concrete on it. That is not in the cards at the moment, though.   Is there a DIY way to make the road more driveable, at least temporarily? I have some gravel about an inch in size, but I fear that the car wheels will simply dig it out again due to the inclination if I put it in with nothing to glue it to the ground. Might mixing concrete with gravel work?


Which of the following series is uniformly convergent?

For $x\in (-\pi, \pi) $, I want to know whether the following series following series are uniformly convergent on  $(-\pi,\pi) $: 1. $\sum _{n=1}^{\infty}{(\frac {x}{n})^n} $ 2. $\sum_{n=1}^{\infty}{\frac {1}{((x+\pi)n)^2}}$. I think series in 2 has to be uniformly convergent for, $|\frac{1}{((x+\pi)n)^2}|$ $\leq $ $\frac {1}{n^2} $ and as $\sum {\frac {1}{n^2}} $ is convergent, by Wierstrass M-test the series in (2) is uniformly convergent. But I don't how to proceed for the series in (1). Any help please!  Also tell if my answer to the (2)nd is correct.


Single word for a person who makes things difficult

I am in search of a word that exactly means 'a difficult person of my description'.  For example, suppose that I am on the lookout for a heart specialist, and I ask my friend if he is familiar with any. Instead of answering this specific question, he begins describing the heart, its function, who can do without it, plausible the danger of being treated by doctors who skipped treatment of the heart in their studies, and so on and so forth. I am lost in a maze, my head goes whirling, and I fail to recollect what I was after.  Search among your acquaintances and you will find many similar examples. What I want is to give them an appropriate name–— preferably a single word.


Adding leaders to point symbols if they overlap using ArcGIS Desktop?

I've added symbols to one of my point shapefiles, but for several datapoints this has resulted in  symbols stacked on top of each other because there are multiple sample types for one sample location (i.e. water, sediment, and benthic samples collected at one station). The result is a cluttered mess! Can I bring a few of my symbols away from the location and have leaders point to the sampling station?     I'm working with ArcView so I can't use the "Disperse Markers" tool. If I download QGIS and deal with my markers in that environment, will my changes "stick" if I bring the layer back into ArcView? (I haven't used QGIS before; is this even possible?)    The Maplex extension suggestion doesn't seem to apply to my situation as I am attempting to remove overlap from symbols, not text. I am tring to determine if I can bring some of my symbols (I have 20 different symbols in the layer in question) out on leaders to aviod clutter. Is this even possible? I don't mind putting in a extra time to "fiddle" with my symbols.


I was drawing smooth curves through points $(a,f(a))$ and $(b,f(b))$ in an attempt to come up with a proof of the Mean Value Theorem. As I was doing that, I noticed that I couldn't draw the curve in such a way that its derivative would be discontinous. I tried to think up a function that is differentiable but whose derivative is discontinous but I got nothing. I did a quick Google search for the same question that I've asked here but all I could find was that differentiability of a function implies continuity of the same which I already know. If $f(x)$ is differentiable over $(a,b)$, does that mean $f'(x)$ is continuous over $(a,b)$? If not, what are some examples of functions where this is not the case?


How do I type the Spanish inverted question mark in Emacs?

I want to write in Spanish without having to keep Charmap open! How do I type the Spanish inverted question and exclamation marks?  ¡Quiero escribir en Castellano sin usar el charmap! ¿Cómo escribo los signos de interrogación y exclamación?   How do I type these characters in Emacs? How do I type them in any general input box in Windows?


script for removing files that are 1 hour old

I need shell script that runs every half an hour on cron and removes the files with extension (*.arc) that are 1 hour ,  old i tried mtime but that has a option only for days old not in terms of hours   it would be helpful if i can get a command or some logic which can run on all types of OS  meaning (hp-ux,linux,rhel etc)  edit:(some of the servers in my work environment have OS that dont have mmin option is there a work around)  can anyone please tell how i wud use tmpwatch or temreaper do delete files (*.arc) older than 1 hr   thank you


How do I quickly navigate to a full path using the "Files" program?

I have this path I want to navigate to in the UI. /usr/local/sbin  How can I do that with a couple clicks in the UI?


My question is this. I'm using this ic mppt SM72445 along with a 250 watt solar panel, mppt output configured to 50.4 or 51 volts, 12-cell lithium-ion battery pack and bms, if the load is less than the output of mppt the battery will be charged, but what happens when the load is greater than the mppt output and there is a voltage difference between the mppt output and the battery? example ; mppt output = 50.4V 5A / battery pack = 46.8V 3.9Vcell * 12 / load = 10A my doubts are for the difference in voltage between the two sources, mppt and battery in parallel


when i try to retrieve data from Firebase database i get this error? and app crashes?

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.safedining, PID: 5315 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.safedining/com.example.safedining.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7656) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)' on a null object reference at com.example.safedining.MainActivity.onCreate(MainActivity.java:65) at android.app.Activity.performCreate(Activity.java:8000) at android.app.Activity.performCreate(Activity.java:7984) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)  at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)  at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)  at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)  at android.os.Handler.dispatchMessage(Handler.java:106)  at android.os.Looper.loop(Looper.java:223)  at android.app.ActivityThread.main(ActivityThread.java:7656)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)  I/Process: Sending signal. PID: 5315 SIG: 9


With relativistic mass increase, what is velocity and distance as function of force and time?

Given a known force (rate of change of momentum), if we also consider the Lorentz mass increase, I'd like to have 2 functions where velocity and distance covered are dependent on time.  I'm talking about velocities where the mass increase is not trivial.  I'm 70, and my differential equation skill, pretty good back in 1969, is completely corroded.


How do I get a map with specific X and Z centers in the Bedrock Engine?

I tried creating maps, then zooming them out, they are not centered at (0 0).  I tried using the /give command with {scale:1,dimension:0,xCenter:0,zCenter:0} at the end, guess what I got? SYNTAX ERROR!!  Can anybody help me create a map with a scale of 1, centered at (0 0)??  P.S. I am playing from my XBox...


How to round this value into 2 decemal places asp.net mvc C#?

I want to round this with 2 decimal places value in c#. Here is my code.  IList<CartModel> CartItems = (from c in db.tblCart                                               where c.User_ID == UID                                               && c.Is_Active == true                                               select new CartModel                                               {                                                   CartID = c.Cart_ID,                                                   UserID = (c.User_ID == null ? 0 : (int)c.User_ID),                                                   SellerID = (c.Seller_ID == null ? 0 : (int)c.Seller_ID),                                                   BuyerID = (c.Buyer_ID == null ? 0 : (int)c.Buyer_ID),                                                   Quantiy = (c.Quantity == null ? 0 : (int)c.Quantity),                                                   Price = (c.Price == null ? 0 :((float)((c.Price*ConversionRate) * c.Quantity))),                                                   Match = (c.Match == null ? 0 : (int)c.Match),                                                                                }).ToList();                 return CartItems;  Price = (c.Price == null ? 0 :((float)((c.Price*ConversionRate) * c.Quantity))) How to apply math.round function on this? Price datatype is float.


How can I format the hardrive of laptop when I am getting error code 0x0000428

Here's the scenario. I have a HP laptop in which I installed Windows 10 Technical Preview a few months ago. Now, when I tried to turn it ON, it gave me an error "Your PC/device needs to be repaired", error 0x0000428. What I exactly want to do is, I want to format my entire hard drive so that I can reinstall Windows 7 in it but I don't know how to format it as I am unable to do anything with that error code in my laptop. I don't have disc for Windows 10 Technical Preview.


What signs can a baby show to indicate he/she is ready for weaning?  What does a parent look for to determine the right timing for this for baby, mom and family?


What does the "Not an answer" flag really mean?

I flagged this answer as, "not an answer":   The answer begins (emphasis mine):     This won't solve your problem, but at least will shorten your code and make it maintainable. Replace your code with following, it will do the same.   In the comments the answerer states:     I don't know the answer. His code seems fine to me, just that style is really bad.   The text describing the "not an answer" flag says:     This was posted as an answer, but it does not attempt to answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.   The flag was declined:     a moderator reviewed your flag, but found no evidence to support it   I cannot imagine a more clear cut match between the text that describes "not and answer", and this particular answer. Since the flag was declined, I am clearly misunderstanding what this flag means.  I'd appreciate it if somebody could put me straight and tell me where my disconnect is.


Can't sort new users by creation date on mobile

The creation date link on the  points to  https://meta.stackexchange.com/users?tab=NewUsers&sort=creationdate   on the desktop version, but  https://meta.stackexchange.com/users?tab=newusers&filter=creationdate   on the mobile version of the site.  The casing doesn't seem to be important, but filter=creationdate gets ignored, sorting the new users by the default key (reputation). Manually editing the URL solves the problem.


On my users computers, Firefox has autoupdated to 20.0, and that's a big problem, because of the new download manager window. They cannot get used to it, they call me constantly at the intercom "hey, where are my downloads???".  If someone knows an hidden setting in the about:config that would restore the old download window, that would save my life


Will I have a better or bad SEO impact if I republish my articles on sites which adding canonical tags back to our site?

Website like Medium allow us to republish the our content on their site. They will give footer credit as well as they add canonical tag to our site....  If we republish our articles on that type of site, Will I have a better or bad SEO impact for my site?


When is the associative law for cartesian product true?

Is it the case that $A \times (B \times C) = (A \times B) \times C$ if and only if one of the factors is the empty set? I am talking about strict equality, not isomorphism. The duplicate question did not answer my question, because it never said when the associative law is true.


My computer boots to a black screen, what options do I have to fix it?

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


How do you manually recover a failed internal HDD?

See bottom of question for edits elaborating on original question  A SATA hard drive suffered mechanical failure (a little while after percussive shock) and OSX declared it unreadable despite correctly ascertaining it's existence and storage capacity (see links below).  Testdisk software, and presumably all other recovery software does not recognise it.  How does one manually recover, byte-by-byte if necessary, the contents of such a hard drive using (physical) tools other than a PC?  Message on plugging in HDD with SATA cable:    Result of initializing anyway:    First Aid does nothing despite returning an 'operation successful' message.  Responses to questions:  @Aganju yes it is still spinning, the HDD vibrates slightly when plugged into a computer. @fixer1234 I believe my question differs in that   The freezer trick is noted as a last resort but  (a biased source I admit but it makes the same argument as other sites) There are new software solutions suggested here, which I will elaborate on ASAP   I am having trouble discerning whether it is spindle/controller/flash memory from the linked question's only answer to mechanical failure.  @davidgo Ddrescue is available for OSX... however, taking your suggestion to put the drive directly into a computer (I have the original laptop which due to insurance has a new drive - I am not attached to this laptop or it's new drive) - presumably I would need to boot a Linux OS (any OS?) from a USB drive?


OpenID Connect - adding custom attributes (claims) to id token

I'm having trouble getting a custom claim attribute to come through in the id_token. I've got the scope set to openid and I've added the custom attribute to the Connected App (tenantId). I also tried implementing a connected app plugin and overiding the customAttributes method.  I checked Configure Id Token in the connected app config page and made sure custom claims was ticked (along with standard claims).  All of the above, and I keep getting back an id_token without the additional claim information. Have I missed anything? I know that i can make a call to the UserInfo endpoint, but i'm trying to avoid that.


How much should university ranking matter while choosing a place for graduate studies?

How much should I weigh in on the ranking of a university (provided by various academic ranking websites) while choosing a university for graduate studies? The universities that I am considering have equally strong faculty profiles in the areas of my interest. So in order to take the final decision, should I factor in this 'so-called' measure of academic repute in the form of rankings?   Though the phrasing of the question apparently makes it akin to how university ranking affects post-Ph.D. prospects, the detailing in my question reveals that I am not really looking for that answer. My question is that if I have been accepted at several places (outside the top 5) all having similar faculty profiles, should I use 'rank' as a deciding factor?


Easy way to prove $\frac{2^n+1}{5^n+1}\gt\frac{2^n}{5^n}$ for all $n\gt0$

I've simply said that adding $1$ to the numerator and denominator when the denominator is $5^n$ (greater than $2^n$), the "$+1$" accounts for a larger portion of the numerator than the denominator, so $\frac{2^n+1}{5^n+1}$ better be greater than$\frac{2^n}{5^n}$ for all $n\gt0$. I'm just not satisfied with this explanation because it seems sloppy and not rigorous... Does someone have a better proof?


when I created one custom exception class just like below   public class MyApppException extends Exception {      private String message = null;      public MyApppException() {         super();     }     public MyApppException(String message) {         super(message);         this.message = message;     }     public MyApppException(Throwable cause) {         super(cause);     } }   compiler giving me below waning      The serializable class InsufficientBalanceException does not declare a static final serialVersionUID field of type long   From Java doc I understand the meaning of serialVersionUID     The serialization runtime associates with each serializable class a version number, called a serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization. If the receiver has loaded a class for the object that has a different serialVersionUID than that of the corresponding sender's class, then deserialization will result in an InvalidClassException. A serializable class can declare its own serialVersionUID explicitly by declaring a field named "serialVersionUID" that must be static, final, and of type long:   But I did not understand why Java declared serialVersionUID in Exception and Throwable class? What is the use of serialVersionUID in Exception and Throwable class? Is it really required? If yes, Why? Someone please clarify.  Exception   public class Exception extends Throwable {     static final long serialVersionUID = -3387516993124229948L;   Throwable   public class Throwable implements Serializable {     /** use serialVersionUID from JDK 1.0.2 for interoperability */     private static final long serialVersionUID = -3042686055658047285L;


Why are the comment upvote and flag options always appearing now?

I just saw now that a new build had rolled out in which the comment upvote and flag options are always visible. Previously, one had to mouse over the area in order to see them.  Why was this just changed? Is it to support touch screens? I'll admit, it was difficult to find the flag button using my touchscreen laptop running Microsoft Edge.  Cross-site duplicate on MSO:


Let $G$ be a finite group and $H$ be a subgroup of $G$. Show that if $aH$ intersect $bH$ is not empty, then $aH$ and $bH$ contain an equal number of elements in $G$. Conclude the number of elements in $H$ divides the number of elements in $G$.


Is it possible and acceptable to temporarily remove specific posts from HNQ?

I need Stack Overflow for working purposes, so I automatically see every now and then the HNQ's.  In my spare time I'm watching  and not past season 6 yet.  Since weekly the episodes of season 7 get published, the HNQ just get flooded with GoT questions every Tuesday. Even the titles that carefully are phrased not to spoil leak hints I simply would like to not have yet. Not to mention the titles that get HNQ before spoilers got removed from their titles.  For me it isn't feeling fair, having a free time activity I enjoy, getting spoiled by the fact that I have to use SO on work.  So is there anything I can do to prevent this? Or is there a way maybe even moderators could prevent this?


When can I be sure a questionable check has cleared?

Someone has sent me a check for $250 in payment for property damage they caused in a car accident.  It would have been better if I had gotten a cashier's check or official check, but I'll have to make do with what I've got.  Since I've spoken directly with the person, and since I have their address and phone number, I'm fairly sure this is a good check.  But I really can't be 100% sure.  So once I deposit it, when can I consider the check to be "cleared"?  That is, at what point can I be sure that the $250 is irrevocably mine?  There are other questions that have dealt with something similar (like the advance-fee fraud that probably underpins ) but since the focus of the question was different, there wasn't a clear answer on the time for clearing a check.  Thanks to anyone who knows.


Link to feedback site in tag filter email does not have the correct formatting

I noticed that the email I received for a tag filter I created on  has the following footer:  Questions? Comments? Let us know on our [feedback site]().  Here's a screenshot of that part as I see it in my inbox:    Can the formatting of the link to Meta SE over the text "feedback site" be corrected?


I have created a proof that$ 1 = -1$ but I know that this is impossible. Could someone help me find the flaw in this proof...  $i = \sqrt{-1}$    Given  $i^2 = -1$       Given  $i^4 =  1$       Given $i^8 =  1$       Given --------------------------All Common Knowledge Above  $i^4= i^8$  Take sqrt of both sides...  $i^2=i^4$  Take sqrt of both sides...  $i= i^2$  $i=-1$  $i^2= -1$ (sub for $i$)  $-1 \times -1$ (sub for $i^2$)  = $1$  $1=-1$  Thankyou all for helping me. I looked at the other questions and this question is not a duplicate. However, we all have one common error; we forgot +- when taking the square root of i^4 = i^2


When I go to the admin profile in Wordpress, I don't see a place to edit the photo for the admin.  Would anyone be able to please suggest to me how to navigate to the place where I can change the admin/user profile photo?  Thank you!


How can you put animated gifs on your desktop? (in windows 7)   I have wanted to do this for a long time. Whenever I put a gif on my desktop it never animates. Is there any software I could use? Thanks in advance.


How do I position one image on top of another in HTML?

I'm a beginner at rails programming, attempting to show many images on a page.  Some images are to lay on top of others.  To make it simple, say I want a blue square, with a red square in the upper right corner of the blue square (but not tight in the corner).  I am trying to avoid compositing (with ImageMagick and similar) due to performance issues.  I just want to position overlapping images relative to one another.  As a more difficult example, imagine an odometer placed inside a larger image.  For six digits, I would need to composite a million different images, or do it all on the fly, where all that is needed is to place the six images on top of the other one.


Relationship between White Walkers and Children of the Forest

After viewing episode 5 of season 6 of Game of Thrones, we have come to know that      the Children of the Forest created the White Walkers.   But it seems that the White Walkers attack the Children of Forest. My question is why they would do so, given their origin.


What do I interpret from the unit root test?


Why is in-class initialization of static const members in C++ restricted to integral data types?

What are the reasons due to which the in-class initialization of static const members is restricted to integral data types in C++ ?


I have this question:     Let $x, n$ be integers with $n \geq 2$ and $n$ not dividing $x$.  Show that the order o($\bar{x}$) of $x \in Z_n$ is   $o(\bar{x})= \frac{n}{HCF(x, n)}$   I've been thinking about it for ages but I still don't get why. A hint would be appreciated.