i need solution where i need to check overlap, end-start match and start-end match like startDateTime=2020-10-24T11:30:34 endDateTime=2020-10-27T17:00:02  jpqlQuery.where(                 (                     (start.loe(startDateTime)                     .and(end.goe(startDateTime)))                      .or((start.loe(endDateTime)                     .and(end.goe(endDateTime))))                      .or((start.loe(startDateTime)                     .and(end.goe(endDateTime))))                      .or((start.loe(endDateTime)                     .and(end.goe(startDateTime))))                     )                 );  need to replace where for following scenarios Scenario      -------------------------   Result start: 2020-10-24T11:30:34 end: 2020-10-27T17:00:02        -- false start: 2020-10-24T11:30:34 end: 2020-10-28T17:00:02        -- false start: 2020-10-23T11:30:34 end: 2020-10-25T17:00:02        -- false start: 2020-10-25T11:30:34 end: 2020-10-26T17:00:02        -- false start: 2020-10-23T11:30:34 end: 2020-10-28T17:00:02        -- false start: 2020-10-28T11:30:34 end: 2020-10-30T17:00:02        -- true start: 2020-10-22T11:30:34 end: 2020-10-23T17:00:02       -- true start: 2020-10-22T11:30:34 end: 2020-10-24T11:30:34       -- true start: 2020-10-27T17:00:02 end: 2020-10-30T17:00:02      -- true all above scenarios should work under single where condition


Typeset a bibliography with entries in several different languages

What is the best way to typeset a bibliography that contains several entries in a number of different language scripts like Latin, Cyrillic, Chinese, Japanese and Vietnamese.  The question centers around the issue if there is (or not) a solution withing pdflatex, for example biber+babel+biblatex or if one HAS o move to XeLaTeX and to Polyglossia.  I currently have a file   \documentclass{article}  \usepackage[utf8]{inputenc}  \usepackage[OT2,T1]{fontenc}  \usepackage[english,french,german,polish,portuguese,romanian,spanish,russian,vietnam]{babel}  \usepackage[bibencoding=auto,backend=biber,babel=other]{biblatex}  \addbibresource{book-lib.bib}  \addbibresource{russian.bib}  \addbibresource{vietnamese.bib}  %\addbibresource{chinese.bib}  %\addbibresource{japanese.bib}   \begin{document}  This is a test.  \nocite{*}  \printbibliography   that stops working as soon as one adds the russian/vietnames biblio enties, with complaints like:  ! LaTeX Error: Command \cyrs unavailable in encoding T1.   when the Russian entries are added and and more as the other are added.


System log full of session and slice messages

I have a new CentOS 7 installation, and noticed that my /var/log/messages file is full of messages like this  Mar  6 08:40:01 myhostname systemd: Started Session 2043 of user root. Mar  6 08:40:01 myhostname systemd: Starting Session 2043 of user root. Mar  6 08:40:01 myhostname systemd: Created slice user-1001.slice. Mar  6 08:40:01 myhostname systemd: Starting user-1001.slice. Mar  6 08:40:01 myhostname systemd: Started Session 2042 of user userx. Mar  6 08:40:01 myhostname systemd: Starting Session 2042 of user userx. Mar  6 08:40:01 myhostname systemd: Started Session 2041 of user root. Mar  6 08:40:01 myhostname systemd: Starting Session 2041 of user root. Mar  6 08:40:31 myhostname systemd: Removed slice user-1001.slice. Mar  6 08:40:31 myhostname systemd: Stopping user-1001.slice. Mar  6 08:41:01 myhostname systemd: Created slice user-1001.slice. Mar  6 08:41:01 myhostname systemd: Starting user-1001.slice. Mar  6 08:41:01 myhostname systemd: Started Session 2044 of user userx. Mar  6 08:41:01 myhostname systemd: Starting Session 2044 of user userx. Mar  6 08:41:21 myhostname systemd: Removed slice user-1001.slice. Mar  6 08:41:21 myhostname systemd: Stopping user-1001.slice.   What do all of these mean, and why are they there?  If this is normal background noise them it seems like an enourmous waste to of resources to log this...


recyclerview list is not displaying in android

Hi in the below code value am adding values to account_name the after that using that adapter doing the set adapter.response is coming the server but values are not adding to the list and list is also displaying.  For displaying used the recyclerview to display the values .  can any one help me where did the mistake  Error:  java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean)' on a null object reference         at com.genworks.oppm.Adapter.MyAdapter.onCreateViewHolder(MyAdapter.java:32)         at com.genworks.oppm.Adapter.MyAdapter.onCreateViewHolder(MyAdapter.java:19)   updated code:  Activity.java:  for(SyncBlocks syncBlocks1:syncBlocks){                          String label=syncBlocks1.getLabel();                          ArrayList<SynFields> synFields=syncBlocks1.getFields();                          ArrayList<SynFields> jsonArray=syncBlocks1.getFields();                          for(SynFields synFields1:synFields){                              String name=synFields1.getName();                              Object values = synFields1.getValue().toString();                              try {                                  if (values instanceof JSONObject) {                                     JSONObject jsonObject1 = new                                             JSONObject(String.valueOf(synFields1.getValue()));                                     String value=jsonObject1.getString("value");                                 }else if (values instanceof String) {                                     //here, you get string                                       String value =  synFields1.getValue().toString();                                     //account_name.addAll(value);                                     String value_names= String.valueOf(synFields1.getValue());                                    // Log.e("account_name", String.valueOf(account_name.add(value)));                                     account_name.add(value_names);                                      //account_name.add(value);                                  }                              } catch (JSONException e) {                                 e.printStackTrace();                             }                          }                          myAdapter = new MyAdapter(getContext(),account_name);                         recyclerView.setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false));                         recyclerView.setAdapter(myAdapter);                      }   MyAdapter.java:     public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {      private LayoutInflater inflater;     private Context mContext;     private ArrayList<String> mSynFields=new ArrayList<>();      public MyAdapter(Context context, ArrayList<String> synFieldsArrayList) {         mContext=context;         mSynFields=synFieldsArrayList;     }     @Override     public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {          View view = inflater.inflate(R.layout.fragment_account, parent, false);         MyViewHolder holder = new MyViewHolder(view);          return holder;     }      @Override     public void onBindViewHolder(MyViewHolder holder, int position) {         holder.name.setText(mSynFields.get(position));       }      @Override     public int getItemCount() {          return mSynFields.size();     }      class MyViewHolder extends RecyclerView.ViewHolder{          TextView country, name, city;         ImageView iv;          public MyViewHolder(View itemView) {             super(itemView);              country = (TextView) itemView.findViewById(R.id.headingText);             name = (TextView) itemView.findViewById(R.id.subHeaderText);             city = (TextView) itemView.findViewById(R.id.subHeadingText);         }      } }


Screen Resolution Problem with Ubuntu 14.04 and VirtualBox

Environment: Lenovo T530 running Windows 7.  Have installed Ubuntu 14.04 on a virtual machine using VM Virtual Box.  Have installed all the updates from both Virtual Box and Ubuntu.  Problem: While in Ubuntu's desktop and other Ubuntu initiated programs, the window is reduced to about 3x4 inches showing in the middle of the rest of my regular Virtual Box window.  I am seeing only the upper right hand of the screen output of what I would normally see.  Please help.   I've seen    But, none of these answers works in 14.04.


Unable to install software using brew install

I am unable to install software using brew install. I have tried brew cleanup & brew update, and deleting the file, but it just does not work!  This is the error message:  ==> Downloading http://ftpmirror.gnu.org/automake/automake-1.14.tar.gz ######################################################################## 100.0% Error: SHA1 mismatch Expected: 648f7a3cf8473ff6aa433c7721cab1c7fae8d06c Actual: 3432ee773dd67c6333bdeda956bd364497630fab Archive: /Library/Caches/Homebrew/automake-1.14.tar.gz (To retry an incomplete download, remove the file above.)


What partitions are required for Ubuntu?

I've been unsuccessfuly partitioning for a while, so what partitions do I need? I'm running a rather old device, with these specs as follows: 3.7 GB ram, Intel Core 13-3220 CPU, Intel Ivybridge Desktop graphics card, GNOME 3.28.2, 64 bits, and a 500.1 GB hard drive (500,107 MB). I am trying to install Ubuntu 18.04.2 LTS, and I would be very grateful if someone could tell me the size, primary/logical, mount point and what it's used as. I am a complete beginner, so I don't know anything, so it would help tremendously if I could get some direction. Thanks!


A single word for someone who is quick to hate others

What is a single word to describe someone who is quick to hate others?   With anger we can say quick-tempered, but what about quick in hating other people/easily hates others.   Hateful means full of hate, but doesn't really give the meaning of being quick to hate people.


Mounted cifs share but no write permissions

Have reinstalled Ubuntu on my web dev server. On the old one I had an smbfs share setup to access a share over the local network to other Ubuntu boxes. It was setup using the following and worked fine -   This time round I am using cifs-utils instead of smbfs, but I presume this is fine?  Upon reinstalling the server I have been having issues making the files writable. Its mounted ok, and when from my local machine I ls -l it shows me write permissions (although from my local user), but when I goto create or save over a file it gives me a no permissions error  Here is the line in my /etc/fstab. I had to make one change to be able to mount, and I added the ,sec=ntlmv2 option, without which I was getting mount error(13)  //192.168.0.40/webserver    /media/webserver        cifs    credentials=/root/.smbcredentials,sec=ntlmv2,iocharset=utf8,file_mode=0777,dir_mode=0777,uid=1000,gid=1000 0 0   and my credentials file (unchanged from when it was previously working)  username=melon password=xxxxxxxxxxxx   How can I fix it so that I have write permissions on my mount?


Proving: $\cos A \cdot \cos 2A \cdot \cos 2^{2}A \cdot \cos 2^{3}A ... \cos 2^{n-1}A = \frac { \sin 2^n A}{ 2^n \sin A } $

$$\cos A \cdot \cos 2A  \cdot \cos 2^{2}A  \cdot \cos 2^{3}A  ... \cos 2^{n-1}A = \frac { \sin 2^n A}{ 2^n \sin  A } $$  I am very much inquisitive to see how this trigonometrical identity can be proved.  PS:I am not much of interested about an inductive proof.


New girl gamer in our D&D group is causing weird tension - what to do?

I'm concerned because a new player just joined our D&D 5e group and is super flirty with all the male players (both in person and as her character - she's a bard). And the problem is that she's changed the whole vibe of our gaming group.  We used to be a really cohesive team, and now almost every decision takes ages to make because the guys are defending all her stupid ideas and not acting from their characters' perspectives. Even our online chats with the DM are strangely sexual now.   The new player is completely NEW to D&D (a complete beginner), and we only met her recently when the DM said she could join the group. Our group is not a friends-group; we met through a gaming group online. The DM likes to get people interested in D&D, so that's how she got in the door. Our group is aged in their 20s; I think (3 of us are over 35). We have mixed genders and mixed ethnicities (though most Australians). Most players are beginners (except 2 of us who grew up playing D&D in the 80s- I'm 1 of such).  I am a female player in the group, but it's not an issue of jealousy for me. If she's super flirty, it reflects badly on her, and in any case, if she "succeeds" in finding a partner, it doesn't bother me. I don't care if people date in our group (we already have a couple in the group).  The issue is that, since she joined our campaign, our team dynamic (in game) has changed. One such problem is that her character is a level 1, and we're all higher levels, so we're constantly trying to "save" her. I find it really annoying that the guys act all "smitten" and can't see she just has changed our group dynamic. It's a rift, and I don't know what to do to fix it.  I have mentioned my problem with this to the DM, who suggests we play harder campaigns. But the DM has not made any decision to kill her character off either way. Do we kill her? Or level her up? Or...?  The net problem is that decisions are taking too long, and the dynamic of the group is leaning on sexual-tension instead of gameplay.  Please share how you have seen a similar problem resolved using our site's ; specifically, back up your answer with relevant experience or citations. An "idea you think might be good" without any evidence isn't a good answer.


How do I turn off Modern UI and get the old Start Menu back in Windows 8?

I just bought a new Windows 8 laptop, but I want to get rid of the new "Modern UI" Start Screen, and get the old Start Menu back. How do I do this?


Is there a function with infinite integral on every interval?

Could give some examples of nonnegative measurable function $f:\mathbb{R}\to[0,\infty)$, such that its integral over any bounded interval is infinite?


When trying to change an item in matrix all item are changing(python 2d list)

mat = [[0] * 5] * 5 mat[1][1] = 3 print(mat[2][1])  expected output is 0 but compiler is giving 3 Can someone please explain me why this is happening.


How do we control web page caching, across all browsers?

Our investigations have shown us that not all browsers respect the HTTP cache directives in a uniform manner.  For security reasons we do not want certain pages in our application to be cached, ever, by the web browser. This must work for at least the following browsers:   Internet Explorer 6+ Firefox 1.5+ Safari 3+ Opera 9+ Chrome   Our requirement came from a security test. After logging out from our website you could press the back button and view cached pages.


I would like to create a matrix with divider lines as shown  in the following figure:    I'm not looking for a straight line like in  answer. any idea on how to do it?  thanks in advance


What is the force that causes it to move and why does it maintain the speed for so long? If it has no mass, why is it effected by mass?


Is forte pronounced “fort” or “for-tay”?

How do you pronounce forte?  Fort or for-tay?


I am facing a new problem. I have the below use case.  var a = parseFloat(10); // Returns 10 var b = parseFloat(1.62); // Returns 1.62 var c = a + b; // Returns 11.620000000000001   I want the c to return 11.62. What is the problem here?


Book about a guy that gets sent to a magical place because of an experiment, becomes a wizard

I'm trying to remember the name of a book series where a guy was broke and signed up to be the guinea pig in an experiment that sent him to a magical land where he ended up being a wizard, an "aa" wizard.   I don't remember much else about it other than he was terrible at being a wizard but automatically was one because he was from somewhere else I guess? And all the other wizards were like "omg peasant, I can't believe I have to deal with you not knowing all this magic stuff already." He spent most of the book trying to get home to his wife.


Id value 0012800000CyJVI is not valid for the Contact standard controller  how to check wrong id in apexpage and show error in salesforce? using standard controller


Does the laplace transform of $1/t$ exist? If yes, how do we calculate it? Putting it in $$\int_0^\infty (e^{-st}/t) dt$$ won't solve.  Is there any other way? If not, why?  Thanks!


"Failed to fetch... Temporary failure resolving..." when trying to install

I am unable to install apache. I get these errors when I try to install it.


True macro lenses come in fixed focal length. Are there any macro lensens which have variable focal lengths? And please explain why yes or why not?


Should users be penalized for answering bad questions?

On , a user decided it was a bad question and downvoted all answers with the comment "-1 closevote, not answer!".  I realize that , but is this the appropriate response?


Existence of a Boolean algebra with a unique ultrafilter in ZF

ZFC proves every infinite Boolean algebra has infinitely many ultrafilters. If every ultrafilter over $\omega$ is principal, then $\mathcal{P}(\omega)/\mathrm{fin}$ has no ultrafilter.  Is it consistent with ZF that there is an infinite Boolean algebra with a unique ultrafilter? Thanks for any help.


I have a board with various logos. I want to make them equal. So I set the equal height, e.g. 10cm.  However, this is not quite right, as logos that are long (e.g. "nice-company"), they visually dominate over logos that are more square (e.g. "box").  Do you have any smart suggestion how to make them visually equals?


Target package configured multiple times in /etc/apt/sources.list

This is the output of sudo apt update :  Hit:9 http://ppa.launchpad.net/openjdk-r/ppa/ubuntu bionic InRelease Err:10 http://ppa.launchpad.net/izx/askubuntu/ubuntu disco Release   404  Not Found [IP: 2001:67c:1560:8008::15 80] Reading package lists... Done                                 W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Translations (main/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Translations (main/i18n/Translation-en_GB) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 E: The repository 'http://ppa.launchpad.net/izx/askubuntu/ubuntu disco Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Translations (main/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Translations (main/i18n/Translation-en_GB) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:41 and /etc/apt/sources.list.d/vscode.list:3 W: Target Sources (main/source/Sources) is configured multiple times in /etc/apt/sources.list.d/izx-ubuntu-askubuntu-disco.list:2 and /etc/apt/sources.list


I have this piece of code  \begin{equation} \begin{split} n_1 &= Tr (O^{eff} \sigma_1 ) \\ &= Tr\Bigg [O^{eff} \begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix} \Bigg ] \\ \end{split} \end{equation}   and I get this when I compile with texmaker    Copy-pasted the same code in Overleaf, the 2x2 matrix looks normal. Any ideas?   Here is a list of the packages I use:  \usepackage{siunitx}   \usepackage{dcolumn}   \usepackage{sidecap} \usepackage{braket} \usepackage{amsmath} \usepackage{caption} \usepackage{wrapfig} \usepackage{bbold} \usepackage{amsthm} \usepackage{url} \usepackage{titlesec} \usepackage{caption} \usepackage{subcaption} \usepackage{appendix}


I’m animating a plate of steel cut by laser rays. My animation is complete for the most part of it but I want to make the overheating of the steel where the laser passes visible. As it passes it assigns another material with emission on the cut border of the meshes of the plate and the borders of the cut pieces. The appearance of the material has to be animated according to the movement of the laser or even in key frames.


Get a List of all Subscribers of an event

hopefully this question is not too stupid ;-)  I need a list of all subscribers of an event.  for example, I got this Code:  Driver.PrimaryMessageReceived += Driver_PrimaryMessageReceived;   Now, I assume there are more that this one 'Driver_PrimaryMessageReceived' handler to the event 'PrimaryMessageReceived'  Is there a way to figure out (in runtime), which and how many subscribers to the event PrimaryMessageReveived have been subscribed?  I found this post:   but it wasnt very helpfull to me.  Thanks in advance


How to set up passwordless SSH access for root user

I need to configure a machine so software installation can be automated remotely via SSH. Following , I was able to setup SSH keys so my user can access the machine without a password, but I still need to manually enter my password when I use sudo, which obviously an automated process shouldn't have to do.  Although my /etc/ssh/sshd_config has PermitRootLogin yes, I can't seem to be able to log in as root, presumably because it's not a "real" account with a separate password.  How do I configure SSH keys, so a process can remotely log in as root on Ubuntu?


Changing the font size of document title

A publication I am submitting to has the rather annoying requirement of needing the document title to be size 16pt (and the regular text size being 12pt, which I know how to do). I have absolutely no idea how to change the font size of the title (beyond adding \Large, \LARGE etc. but none of these correspond to 16pt).  How would I go about setting the font size of the title to a specific size?


Star operator (*) applied to lists and integers

Let's say we have a Foo class and we want to instantiate a lists of foos, which we can do as follows:  foo_list = [Foo()] * 3   Now what if we do foo_list[0].x = 5? This statement will set the attribute x to all of the instances inside the list!!!  When I found this it blew my mind. The problem is that when we create a list like that, apparently python will create the Foo instance first, then the list instance, and then append the same object to it 3 times, but I really would expect it to do something like this:  foo_list = [Foo() for i in range(3)]   Wouldn't you too? Well, now I know that definitely this syntactic sugar can't be used as I wanted to use it, but then, what is it used for? The only thing I can think of is to create a list with an initial size like this: list = [None] * 5, and that doesn't make much sense to me in the case of python.  Does this syntax have any other really useful use case?


Ubuntu can't detect external 4TB Seagate hard drive after accidently formatting and stopping immediately

I used sudo mkfs.vfat /dev/sdb to format  a flash drive (I didn't notice /sd*) but accidentally my Seagate external hard disk (/dev/sdb) started being formatted and immediately after few seconds I cancelled that command. I was still able to use the hard disk as it was already mounted to my Ubuntu machine, but when I unmounted it and tried to access it Ubuntu didn't detect it anymore. Results of sudo mount /dev/sdb /media/backup: mount: /media/backup: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error.  Results of sudo fdisk -l # pasting the last few paragraphs: Disk /dev/sda: 931.53 GiB, 1000204886016 bytes, 1953525168 sectors Disk model: ST1000DM003-1ER1 Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: dos Disk identifier: 0x7f7a3175  Device     Boot     Start        End    Sectors   Size Id Type /dev/sda1  *         2048  199999487  199997440  95.4G 83 Linux /dev/sda2       200001534 1953523711 1753522178 836.1G  5 Extended /dev/sda5       200001536 1953523711 1753522176 836.1G 83 Linux  Partition 2 does not start on physical sector boundary. Disk /dev/sdb: 3.65 TiB, 4000787029504 bytes, 7814037167 sectors Disk model: BUP Portable     Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes  Results of df -h: Filesystem      Size  Used Avail Use% Mounted on udev             12G     0   12G   0% /dev tmpfs           2.4G  1.8M  2.4G   1% /run /dev/sda1        94G  9.4G   80G  11% / tmpfs            12G  197M   12G   2% /dev/shm tlsblkmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs            12G     0   12G   0% /sys/fs/cgroup /dev/loop0       56M   56M     0 100% /snap/core18/1988 /dev/loop2       32M   32M     0 100% /snap/snapd/11036 /dev/loop1       65M   65M     0 100% /snap/gtk-common-themes/1514 /dev/loop3      219M  219M     0 100% /snap/gnome-3-34-1804/66 /dev/loop5       33M   33M     0 100% /snap/snapd/11107 /dev/loop4       52M   52M     0 100% /snap/snap-store/518 /dev/sda5       823G  716G   65G  92% /home tmpfs           2.4G   28K  2.4G   1% /run/user/1000  Results of lsblk: NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT loop0    7:0    0  55.5M  1 loop /snap/core18/1988 loop1    7:1    0  64.8M  1 loop /snap/gtk-common-themes/1514 loop2    7:2    0  31.1M  1 loop /snap/snapd/11036 loop3    7:3    0   219M  1 loop /snap/gnome-3-34-1804/66 loop4    7:4    0    51M  1 loop /snap/snap-store/518 loop5    7:5    0  32.3M  1 loop /snap/snapd/11107 sda      8:0    0 931.5G  0 disk  ├─sda1   8:1    0  95.4G  0 part / ├─sda2   8:2    0     1K  0 part  ─sda5    8:5    0 836.1G  0 part /home sdb      8:16   0   3.7T  0 disk   My PhD career is based on data inside it. Please help to restore my data.


T and T* have the same Eigenvectors then T is normal

This is a Homework question i'm struggling with.  T is a linear map over C. Prove: if T and T* have the same Eigen-vectors then T is normal.  I've been breaking my back over this one... A complete solution would be nice but any help would do. thanks. Michael


Make it possible to retract comment flags

I misread the content of a comment, and flagged it. Then I realized that the comment wasn't what I had initially thought. Would it be possible to have the ability to retract comment flags, just like we have the ability to retract flags on questions and answers?  I'm aware of this  . But the answer there is just that it's not possible. At the time it was not possible to retract any flags.   This is a separate  which requests that it may become possible to retract comment flags.  If I've realized a flag was a mistake, I think it's unnecessary to keep it in the queue of content the moderators have to look at. Also, it would add an unnecessary "rejected" to the flaggers statistics. Sure, people should think before they flag. But everyone makes mistakes sometimes.


JAVA Exception in thread "AWT-EventQueue-0: NullPointerExecption"

I am doing this programming assignment for uni and I am using an ArrayList, now when I select a button I want a textfield to display the farm name text from that ArrayList. Here is a screenshot of my code and errors. The code for jtfFarmName.setText.... works out of "display(int i)" but when I put that code in "display(int i)" and call it like this "display(0)" it gives me that error.  Any help would be amazing, thanks. It is really annoying me. I have already initialized the farm variable;


Is the Heisenberg uncertainty principle based on experimental imprecision in measurement?

As far as I understand, the Heisenberg uncertainty principle states that the more one of the conjugate quantities are known, the less the other is known. So for instance, if the velocity of a particle is known more precisely, its location will become known less precisely.  I also read somewhere that it's because if you direct some ray at the moving particle, the ray will reflect, giving the former position of the particle, but the whole collision between the ray and the particle changes the particle's momentum, thus only one can be measured at a time which is the Heisenberg uncertainty principle.  In that case, if there is an indefinitely precise measuring device that can detect the particle's position and velocity at the same time, can the Heisenberg uncertainty principle disproved? Also, does the Heisenberg uncertainty principle apply only to subatomic particles, or large objects too?


Does the Hex spell's damage apply to spell attacks?

The Hex spell increases the damage when you hit with an attack and Eldritch Blast is a spell which causes you to make a spell attack roll.  Does any attack roll trigger the extra damage of Hex, or only attacks generated by the attack action?


SD Card showing weird file names and files are lost

I just plugged my SD Card to my PC after a long videography day, and I suddenly got this problem:    It is also not showing all the videos I took on my camera so what is the solution?


Modelling the number of apples an orchard yields with diminishing returns per tree

This is   in the University of Washington's precal book.  Sylvia has an apple orchard. One season, her 100 trees yielded 140 apples per tree. She wants to increase her production by adding more trees to the orchard. However, she knows that for every 10 additional trees she plants, she will lose 4 apples per tree (i.e., the yield per tree will decrease by 4 apples). How many trees should she have in the orchard to maximize her production of apples?  Instructing a precal class, I walked through my approach to answering this in class (without preparing) and ended up doing something strange that may have confused the students. How would you clearly explain a way to get the function for the number of apples that we are trying to maximize? More generally, how would approach answering this question? It'd be nice to collect a some different approaches to demonstrate to my students that there is not a single rigid correct way to solve a problem.


Where can I ask questions about which laptop to purchase?   I need help to choose between two laptop brands; is there a Stack Exchange site for these type of questions?


Story that includes a description: "Two concentric circles, intersecting at three points"

I am trying to find a story I read as a child.  I remember little about it except for the following:   I suspect I read it before 1985, but it was a school library book which means it could be God knows how much older than that.   This may mean it was a book meant for younger readers.  In memory it "feels" longer than a short story, but I was a bit young to be reading novels.  If I had to guess, I would guess novella length or shorter. English language, available in the United States. Contains several descriptions and ideas that stuck with me:   The overall idea was that there were "parallel" worlds, parallel like the pages of a book, except for one that was (for whatever reason) skew to the rest, or warped somehow, and therefore intersecting the rest Geometry between that world and the rest seemed fundamentally incompatible as a result The most evocative example of this (by definition, since it is the only one I recall with clarity) is a description of... something... as looking like "Two concentric circles, intersecting in three places."  This is obviously gibberish (concentric circles intersect nowhere unless they also have the same radius in which case they overlap perfectly; non-concentric circles that do intersect do so only at two points) but I was just old enough to realize it was gibberish being used to a purpose.  It stuck with me.


How to show that  $$ \lim _{\alpha \rightarrow \infty } \sup_{t \in \left [0,T \right]} \left | e^{-\alpha t} \int _ 0 ^t e^{\alpha s} ~ dB_s \right | =0, \ \ \text{a.e.} $$  where $\left (B_s \right)_{s\geq 0}$ is a real standard brownian motion starting from zero ?


What is today's date vs What date is it today?

What is today's date vs What date is it today ?  Is there an alternative to this?


If an effect would prevent a spell from doing damage, does it continue to prevent that damage after the spell changes zones?

Anthony casts , targeting Nathan's .  Nathan casts and resolves , choosing to 1) prevent all damage that would be dealt by Searing Blood this turn and 2) put a +1/+1 counter on Elvish Mystic.  Searing Blood resolves, deals no damage, and goes to the graveyard.  Anthony casts and resolves  to kill Elvish Mystic.  Searing Blood triggers from the graveyard, because Elvish Mystic died. Does the prevention effect created by Dromoka's command still apply to it after it changes zones? In other words, will Searing Blood deal 3 damage to Nathan?


The [virtual-method] tag should be a synonym of [virtual-functions]

When I try to suggest to make  a synonym of , I get an error message about a reverse synonym:    The reason seems to be that  has itself a synonym, . Both of those tags should be made synonyms of .


How do I drywall when the studs are not flush?

I have a problem with my bathroom. I recently had someone come and switch the door from the kitchen side to the other side while redoing my kitchen. He did a great job and the kitchen looks great. That being said he used new studs to re-frame the wall and those studs are smaller than the 2x4's used 100 years ago on the original bathroom. I do not know how to correct this issue while dry-walling.... Any suggestions would be great! Thank you i have provided a picture.


Does it make any sense to complain about App Store app review?

Apple has refused my app, but I can not accept reason. They said it is not able to fully loaded, but on all device, conditions etc. work well for me.    Do you think is it any chance they read my complain, and tries to recheck my app, or better to submit and wait an other 1 week for review?     We discovered one or more bugs in your app when reviewed on iPad running iOS 8.2 and iPhone running iOS 8.2 on both Wi-Fi and cellular networks. Specifically, we found that your app is unable to fully load and function.


Can a batch file tell if a program is already running?

I want to use a conditional in my batch file, so that it opens a program, but only if that program isn't already running. Very roughly, something like:  @echo off  ::(Insert IF conditional here, if program is running, then exit, if not, then continue)  cd "C:\xampp" start xampp-control.exe  exit   I'd be super appreciative of any idea. Thanks!


Cant get the wifi to work on Macbook air early 2015 (Ubuntu 15.10)

As i have low internal memory only 128 GB. so i do not wish to install in my hard drive. Instead i wish to use it on my flash drive itself with persistence. My problem is i cant get the wifi to work.


Prove that Group Ring RG is not a Division Ring for R commutative and G a finite group

How do I prove that a group ring RG is not a division ring, assuming that R is commutative and G=(g_1,g_2,...g_n) finite? I understand that I need to show there exists some element of RG that is not a unit. But how do I find such element? Would the element g_1+g_2+g_3+....+g_n work?


How to change text format of summary/trimmed field?

Is there a straightforward way to change the summary/trimmed text to "full html" in Drupal 8?  There are workarounds such as creating separate body fields and using them as the summary but I am specifically asking about changing the text format of default summary/trimmed field of "Text (formatted, long, with summary)".  To put it another way, how to I add the CKEditor bar to the summary/trimmed text.


Why must the name on my passport match the booking details?

I've recently booked some flights using my 'nickname' instead of my full birth name that appears on my passport (Rob verse Robert).  I've since contacted two airlines (RyanAir and Aer Lingus) and both told me I needed to correct the booking mistake.  The Aer Lingus rep mentioned that the specific destination was particularly strict and that I would need to sort this out.  Both airlines were happy to fix this for me, free of charge, but I'm left wondering 'Why does it matter?'  I was told 'security'.  But I don't understand how this increases security.  I've also been told airlines do it simply to find another reason to tack on a 'name change fee' but, in my experience, airlines make it quick, easy and free to update the name.  So, is there any real reason for this?  I can't imagine any scenario where it serves any purpose.


Proposed methods for countering plagiarized text in tag wikis

A pet peeve of mine is people who copy and paste text from Wikipedia for tag wikis, don't source their text, and then get approved in the blink of an eye.    I'm aware that you can Improve a tag wiki , but I'm not quite there yet.  So my options are:   wait for the wiki to get approved anyways, go back and either add a source or clean up the text, or ... reject the edit, and hope that two other people notice the problem and flag the same.   You can guess which option happens much more often.  So, I have a few thoughts on how to handle this:   One or two (preferably one) "Copied content" rejection should immediately reject the tag wiki edit. Each "Copied content" rejection increases the number of votes required to approve the edit by 1 or more votes, in the hopes that others are given enough time to flag appropriately. Any "Copied content" rejection voids any previous approvals, effectively starting the review process over.     BONUS FEATURE:  Once an edit has been flagged as "Copied content", if you try to approve the edit, you get a warning first along the lines of "There are one or more "Copied content" rejection flags, are you sure you want to approve this?"  DOUBLE-BONUS FEATURE:  As above, but once any edit has been flagged for any reason, if you try to approve the edit, you get a warning first indicating that the edit has one or more rejection votes.  ...  Personally, my vote would go to #1 or #3, as #2 might be difficult to implement (but I have no idea what the code base looks like, so I could be completely wrong here).  The only problem with #1 I could see is that the "Copied content" flag would have to function differently for tag wiki edits than regular edits; otherwise, you could have people flagging everything as "Copied content" just to reject an edit quickly.  Option #3 could function as-is for both tag wiki edits and regular edits, since I don't think we wouldn't want copied content to be approved for either questions, answers or tag wikis.    Update 2013/02/04  After a week of giving the review queue another try again, I'd be in favor of Option #3 plus the DOUBLE-BONUS FEATURE.   It's a small sampling of data, but I pretty consistently came in as vote #3 on a Copied Content edit, would vote to reject, and then watch as the edit got its third approval vote (fourth vote in total) shortly afterwards.   If approval votes got cleared out from a Copied Content rejection and all future reviewers would see upfront that there is a rejection flag against the edit, this would go a long way to making sure the edits are handled properly.


Just trying to understand why destructor is called outside of the scope of USING after instance is dispose. I know there is no need for destructor when IDisposable is implemented. Here is my example:  using System;  namespace Destructor {     class Program     {         static void Main(string[] args)         {              using (var a = new A())             {                 Console.WriteLine("... inside USING ...");             }              Console.WriteLine("...END...");         }     }      //............................................................      class A : IDisposable     {         public A()         {             Console.WriteLine("...Constructor called...");         }          ~A()         {             Console.WriteLine("...Destructor called...");         }          public void Dispose()         {             Console.WriteLine("...Dispose called...");         }     } }      Output:      ...Constructor called...      ... inside USING ...      ...Dispose called...      ...END...      ...Destructor called...


How to use oEmbeds on Post Content during AJAX requests

I have an AJAX request that returns a post. The post_content has links to Twitter, YouTube, TED and other platforms that are registered as oEmbed providers in a default, vanilla WordPress install. By now, the WordPress oEmbed handler does not register them and displays plain links and nothing else.   How can I fetch content via AJAX with oEmbed support?


Adding more features improves the variance explained by PCA but the prediction model performs worse

With my 37 base features, I obtain a PCA 7 components whose explained variance is 62584.661. Below is my code (I use scikit-learn):  >> pca = decomposition.PCA() >> X = set_1.to_dataframe().drop(['user_id', 'TARGET'], axis=1) >> pca.fit(X)  >> print pca.explained_variance_    [6.14280876e+04   4.54217662e+01   2.72989436e+01   2.67631322e+00    1.82282196e+00   1.21712136e+00   1.14632304e+00   9.78220983e-01    5.29859226e-01   4.46864198e-01   2.20896621e-01   1.35477040e-01    1.24036813e-01   1.16983213e-01   9.77577393e-02   9.52879856e-02    6.33013163e-02   5.11503915e-02   4.46737594e-02   4.17721621e-02    3.62836939e-02   2.81101420e-02   2.40227513e-02   1.73247899e-02    9.59248897e-03   5.97952400e-03   2.32278409e-03   1.53377399e-03    1.13924785e-03   3.69972626e-04   5.94762833e-28   5.94762833e-28    5.94762833e-28   5.94762833e-28   5.94762833e-28]   >> pca.explained_variance_[:7].sum()  62584.661944243671   Using these 7 PCA variables in my linear regression model, I obtain 0.20 as the r2 value.  To improve the results, I add 39 more features (76 in total). Following the same steps, PCA results indicate 71052.64 as the variance explained with 76 components. However, when I run linear regression using these 76 components, I obtain a r2 of 0.06 that is less than 0.20 of the previous model.  I wonder if I am doing something wrong in my experiment. Is this behavior expected? I thought I would get a better model with a PCA that explains more variance.


error:Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

I get this error when I insert an interstitial ad. Help me  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     mBinding = DataBindingUtil.setContentView(this, R.layout.module_home_activity_home);     mViewModel = ViewModelProviders.of(this).get(HomeViewModel.class);     getLifecycle().addObserver(mViewModel);      initView();     subscribeUi();      MobileAds.initialize(this, "ca-app-pub-3940256099942544~3347511713");      mInterstitialAd = new InterstitialAd(this);     mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");     mInterstitialAd.loadAd(new AdRequest.Builder().build());      Button tvOk = (Button) findViewById(R.id.tvOk);      tvOk.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {             if (mInterstitialAd.isLoaded()) {                 mInterstitialAd.show();             }         }     });      mPermissionReqHandler = new PermissionReqHandler(self()); }   Logcat Message:      FATAL EXCEPTION: main Process: com.xxx.xxx, PID: 29573 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx.xxx/com.xxx.xxx.app.tally.module.home.HomeActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)     at android.app.ActivityThread.-wrap11(Unknown Source:0)     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)     at android.os.Handler.dispatchMessage(Handler.java:105)     at android.os.Looper.loop(Looper.java:164)     at android.app.ActivityThread.main(ActivityThread.java:6541)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference     at com.coderpage.mine.app.tally.module.home.HomeActivity.onCreate(HomeActivity.java:86)     at android.app.Activity.performCreate(Activity.java:6975)     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)      at android.app.ActivityThread.-wrap11(Unknown Source:0)      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)      at android.os.Handler.dispatchMessage(Handler.java:105)      at android.os.Looper.loop(Looper.java:164)      at android.app.ActivityThread.main(ActivityThread.java:6541)      at java.lang.reflect.Method.invoke(Native Method)      at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)


Install Windows 7 on macoS High Sierra (MBP Late 2011)

Device: MacBook Pro 8,2 (Late 2011)  Operating System: macOS High Sierra  Security Update: 2020-002  Boot Camp: Version 6.1.0 (6067.60.1)    Context:  A couple of weeks ago I decided it was time to do a clean install - from scratch - of my macOS High Sierra and Windows 7 operating systems installed on my MacBook, after a year of use. I used this  as a guide to install macOS High Sierra:  The installation was correct and without errors, after that I installed the updates from the App Store following the steps of the support website for the installation of Windows 7 from macOS High Sierra with Boot Camp:   .  Issue:  Following the process above, Boot Camp created the installation drive, the disk was partitioned during the process and when the computer restarted, this error appeared:     No bootable device -- insert boot disk and press any key     I have been searching for ways to install Windows 7, without success. Among them:   Try 5 different USB 2.0 drives (HP, Sandisk, Kingston): Since in a video they think that the problem with this black screen warning is due to USB. Install Windows 7 creating the boot from Windows on a PC with the Rufus application and start from the Mac boot screen (without using Boot Camp). It did not work, although if it recognized the usb with Windows 7 it was frozen when clicked, however with the ISO of Windows 10 following the same procedure if it installed correctly, but the version of my MacBook does not have the complete drivers for Windows 10 in addition to which in my opinion is quite slow compared to Windows 7.     I have done the same installation process with BCA to install Windows 8, 8.1 and 10 and have got the same result.     No bootable device -- insert boot disk and press any key


I realize this has been asked many times and many of the answers seam well written, but I'm missing something with my little task.  Trying to pass a Shell variable (an argument in this case) to awk to grab a section of a text file out.  cat ~/work/junk.txt   [Section1] innerline1 innerline2 innerline3  [Section2] innerline4 innerline5 innerline6   I'm trying to make a script to use the provided argument ($1) to pass as the pattern to match in awk.  #!/bin/bash  echo pattern is $1  # record separator (RS) is the next blank line awk -v var="$1" {print '/var/'} RS= ~/work/junk.txt   If $1 is the argument provided as "Section1" I expect this output:  [Section1] innerline1 innerline2 innerline3   I think I'm close, but yet so very far.  Thanks for any ideas.


Does energy expenditure require movement?

In every formula I've seen that involves energy, I've also seen a distance element. Is there nothing that doesn't involve movement? For instance if I hold my arm out parallel to the ground with a weight in it, my arm will get tired very quickly but according to the formulas I've done no work (force * distance) since distance is 0 and I'm not even applying any force (mass * acceleration) because the mass is not accelerating.  Where's the flaw in my understanding?


Equilibrium and movement of a cylinder with asymmetric mass centre on an inclined plane

A cylinder whose cross section is represented below is placed on an inclined plane. I would like to determine the maximum slope of the inclined plane so that the cylinder does not roll. The mass centre (CM) of the cylinder is at a distance r from the central axis. The cylinder consists of a cylindrical shell with mass $m_1$ and a smaller cylinder with mass $m_2$ placed away from the axis and rigidly attached to the larger cylinder. What is the influence of friction? Is it possible to establish the law of the movement? I think that the piece may roll upwards until it stops.  The figure was copied from Projecto Ciência na Bagagem --       EDIT: Depending on the initial conditions is it possible to find the highest point the cylinder rolls to, before stopping?  EDIT2: From Institute and Museum of the History of Science --  [another cylinder]     "When placed on the inclined plane,   [another] cylinder  tends to   roll upward, coming to a halt at a   well-determined position."


I'd like to make everything grayscale. The utility xcalib can be used to invert the colours displayed (every colour displayed is changed to its compliment) using the following command:  xcalib -i -a   How could I make the display grayscale? Could I desaturate in some way, for example?  Thanks!


Let $\textbf{A} \in M_{n\times n}(\mathbb{C})$ be a Matrix and $\textbf{A}^m=\textbf{I}$ where $m\neq \infty$. Show (with Jordan normal form) that $\textbf{A}$ is diagonalizable. I have no clue how to do that...


Wondering if having identical, verified correct by the Google Structured Data Testing Tool, JSON-LD Schema data on index and the same JSON-LD Schema Data on all subpages would create any sort of problem with google search engine?  Could this be hurting my ranking?  Webmaster Console recognizes pages with it, and is not complaining.


.exe downloads will not open to install. My laptop is new

I am able to download the .exe files but I cannot open or install on Ubuntu. Advice please. My laptop is 1 day old


How to simulate polyhedral dice in Minecraft?

A dispenser can simulate dice of up to nine sides by random choice, and there are redstone circuits for simulating six-sided dice. But how do you simulate, say, ten-sided, twelve-sided or twenty-sided dice in Minecraft?


Allow bounty owners to comment on questions they've placed a bounty on, even if they have less than 50 reputation

After offering a bounty to , I realize that I cannot comment on the question because I no longer have the required reputation. Is it possible to change this behavior, so that the bounty owner can comment only on the post with the bounty irrespective of their reputation? While bounty owners are told that they'll lose privileges at the time they place a bounty, it makes sense to allow them to interact with potential answerers/commentators to help solve the problem, or at least provide additional information.


FOR loop: pass 2 variables from a file simultaniously

I am writing shell script, to extract 2 variables from a file, and have used below FOR loop.   for i j in `cat list`                 do                 echo title                 echo total "$i" "," "$j"                 echo end done   where cat list is  AAA 111 BBB 222 CCC 333   Getting error as `j' unexpected, I have used "while loop" but no luck.   expect output is   title total AAA,111 total BBB,222 total CCC,333 end


I want to switch from Ubuntu 16.04 to Fedora 27, so I made a bootable USB, but it always shows the error in the title.  I tried for hours to solve it, also installed intel-microcode, but nothing seem to work.  Does someone have an idea?  Thanks


I've recently finished a project, during which many DB tables were created.   Most of these tables contain temporary garbage, and I am looking for a simple way to list all these tables.  Is there a way to list all DB tables sorted according to their creation date?


Is there a way to use the covariance matrix to find coefficients for multiple regression?

For simple linear regression, the regression coefficient is calculable directly from the variance-covariance matrix $C$, by  $$ C_{d, e}\over C_{e,e} $$ where $d$ is the dependent variable's index, and $e$ is the explanatory variable's index.  If one only has the covariance matrix, is it possible to calculate the coefficients for a model with multiple explanatory variables?   ETA: For two explanatory variables, it appears that $$\beta_1 = \frac{Cov(y,x_1)var(x_2) - Cov(y,x_2)Cov(x_1,x_2)}{var(x_1)var(x_2) - Cov(x_1,x_2)^2} $$ and analogously for $\beta_2$. I'm not immediately seeing how to extend this to three or more variables.


Row colour gaps in tabularx with \aboverulesep and \{}

\documentclass[]{article} \usepackage[table,dvipsnames]{xcolor} \usepackage{multicol,booktabs,tabularx}  % Table settings \renewcommand{\aboverulesep}{1pt} \renewcommand{\belowrulesep}{1pt}  \begin{document}     \begin{tabularx}{\textwidth}{@{}X l@{}}         This is Header 1 & This is Header 2 \\         \toprule         \rowcolor{Apricot}         This is Text 1 & This is Text 2 \\\midrule         This is Text 1 & This is Text 2 \\\midrule         This is Text 1 & This is Text 2 \\         \bottomrule     \end{tabularx} \end{document}   I have the above table MWE using tabularx, and I am trying to colour the row from the table. However, due to the use of my \aboverulesep and \belowrulesep, I now have gaps above and below my table row that is not coloured.   Also, because of the use of my @{} on either side of the table to 'remove' the excess padding on the sides of the table, the row colour is being applied in those padding as well.   Qn 1: How can I colour the aforementioned gaps (arising due to the \aboverulesep) in, while maintaining the rule separation?   Qn 2: How to remove the colour from the two sides of the table?     EDIT  This is in response to Zarko's answer. I want to maintain the use of @{} on either side to remove the padding. If I were to adapt this into your answer, like so:  % @Zarko's answer \documentclass{article} \usepackage[table,dvipsnames]{xcolor} \usepackage{booktabs, cellspace, tabularx}  % Table settings \renewcommand{\aboverulesep}{0pt} \renewcommand{\belowrulesep}{0pt} \setlength\cellspacetoplimit{5pt} \setlength\cellspacebottomlimit{5pt}  \begin{document}     \begin{tabularx}{\textwidth}{@{}SX Sl@{}}% <-- S is append for activate additional vertical space          This is Header 1 & This is Header 2 \\         \toprule         \rowcolor{Apricot}         This is Text 1 & This is Text 2 \\\midrule         This is Text 1 & This is Text 2 \\\midrule         This is Text 1 & This is Text 2 \\         \bottomrule     \end{tabularx} \end{document}   I obtain this:   and so my second question (Qn2) is still unresolved.. For Qn 1, I prefer to use the solution by @Skillmon with \renewcommand{\arraystretch}{1.15} as I need not add a new package.


May I use Google Fonts for creating a logo with commercial purposes?

I want to create a logo for a contest, the winner will be paid and the winning logo will be the institutional logo of an academic entity, so I need a font which can be used freely or at a cheap cost for commercial purposes.  I see that Google Fonts are delivered as "free fonts" for websites:  May I use them freely for graphic design products (a logo in particular) as well?


What flag should be used when it appears that a user is asking how to program malicious code through stack overflow?  Example Question:   I used the "it needs moderator attention" option and then selected "other", but is this the best tactic?


Windows Defender reported a virus on my PC: Trojan:Win32/Varpes.M!cl. Avast reported another: Win32:Conduit-F. How can I check if the virus is running? I did not find any suspicious entries in LOCAL MACHINE (and CURRENT USER) Microsoft Windows CurrentVersion Run / RunOnce.


\begin{align}   \mathcal{L}_{\lambda} =  u_{1}(h) - u_{1}(h^{*}) + T \geq 0 \text{(foc$\lambda$)}, \label{eqn:foca1}\\   \mathcal{L}_{T} = -1 + \lambda = 0 \Leftrightarrow \lambda = 1 \text{(focT)} ,\label{eqn:focb1}\\   \mathcal{L}_{h} =- u'_{2}(h) + \lambda u'_{1}(h) = 0 \Leftrightarrow \lambda = \frac{u'_{2}(h)}{u'_{1}(h)} \text{(foch)}.\label{eqn:focc1}\\   \lambda \geq 0 \text{(nn)}, \label{eqn:focd1}\\   \lambda \mathcal{L}_{\lambda} =  \lambda [u_{1}(h) - u_{1}(h^{*}) + T] = 0 \text{(cs$\lambda$)} .\label{eqn:foce1} \end{align}   I want to have foc$\lambda$, \text{(focT)}, etc, as an equation number on the other sides if that makes sense?


Kali-Linux dual boot doesn't work well: I cannot choose the operating system at boottime

I installed Kali Linux as dual boot and it works well, i.e. I had both Windows 10 and Kali Linux and before loading the operating system, the bootloader asks for the operating system to load.  Now, 5 days ago, I reinstalled Windows 10 and formatted the disk which contains Windows 10. I successfully installed it and it's working well.   The problem is that now, it no longer asks about which operating system I want to choose. It systematically loads Windows 10, so I no longer have a working dual boot.  One important thing: I installed Kali Linux on a separate drive. I made another drive (taking space from "drive D" and not from the Windows drive which is "drive C").  That drive which I made only for Kali Linux didn't get formatted during the reinstallation of Windows 10.  sorry about I give you pain to read the such a long article but I have to clear the overall scenario


I have hundreds of stored procedures in my SQL Server 2012 database.  From my c# code, I am calling one of the stored procedures which in turn calls another stored procedure and so on.  There is a failure in stored procedure execution. I need to debug it. For that I need to know what are the values which are sent as parameter when calling stored procedure inside another stored procedure .  I cannot alter the stored procedure, is there any way to Watch and StackTrace stored procedures?  Yes, I am using Visual Studio 2010


Why am I so bothered when a topic is being explained, the speaker interrupts the flow and inserts "but more importantly..."  This usage is very, very common. But is it consistent with English grammar? My inclination would be to say "but more important..." and then proceed to explain what I wish to insert. Am I incorrect?


How can there be a current and an electric field in an idealized wire with no voltage drop?

In an ideal circuit, How can there be a current b/w points a & b, when there is no potential difference and thus no electric field between a & b? If there is no current, then where does current across the resistor come from, because that means no charge is coming from the battery (?).


Is there a way to shorten(not remove) the path displayed in the terminal by an alias

I want something like this:  "vivek@grishma:~/xxx/yyy/zzz/src$" to be shown as  "vivek@grishma:datasource$" where I would somehow have predefined "datasource" to be an alias for the long path above.  using the alias command as  " alias datasource='~/xxx/yyy/zzz/src'"   is useful for navigation but it does not take out the long path in the prompt.  Is this possible?  PS- I dont want it to be just "vivek@grishma:" as then each time I should run pwd to know my working directory.


Showing a bijection between the set of ringhomomorphisms $\mathbb{Z}[i] \to R$ and the set of $x \in R$ for which $x^2+1=0$

I am studying basic ring theory and I am stuck on the following (possibly easy) question.     Let $R$ be a commutative ring. Prove that there is a bijection between the set of ring homomorphisms $\mathbb{Z}[i]\to R$ and the set of $x\in R$ for which $x^2+1=0$.   Some  things I remember and can prove:   If $f$ is a ring homomorphism then $f(1)=1, f(a+b)=f(a)+f(b)$ and $f(ab)=f(a)f(b)$. Also $\mathbb{Z}[i]^* =\{1,i,-1,-i\}$ and I can prove $\mathbb{Z}[i] \cong \mathbb{Z}[X]/(X^2+1)$. My idea would be to construct a map from the set of ring homomorphisms to the set of $x \in R$ for which $x^2+1=0$ and show that it's bijective. The problem is that I don't know how to construct such a map (what does the set of ring homomorphisms look like?) and where to use that $R$ is commutative.  Any answer/big hint would be appreciated. Thank you.


Does the potion of clairvoyance require concentration?

The potion of clairvoyance says:  When you drink this potion, you gain the effect of the clairvoyance spell.  This is different than the potion of gaseous form and others:  When you drink this potion, you gain the effect of the gaseous form spell for 1 hour (no concentration required) or until you end the effect as a bonus action.  Emphasis mine. If a potion granting a spell effect doesn't say "(no concentration required)", must you concentration on it?


How would I compute the minimum union bounding box given a list of bounding boxes?

Constraints:  Assume -90 < latitude <= 90 and -180 < longitude <= 180.  A bounding box has the form [minLon, minLat, maxLon, maxLat].    Concerns:   A solution should be clever to realize that 2 boxes on either side of a boundary should be merged over that boundary.   Ex: Box_A has left/right longitude bounds of (177, 179), and box_B has (-179, -177). The result should compute (177, -177) and NOT (-177, 177).... may have confused this here, but look at the pictures below to see what I am getting at.  If 2 boxes are disjoint, (in my head) there are 4 possible union boxes:   Box A is merged with box B on either the left, right, top, or bottom of box A.  More than 2 boxes could really slow down a naive approach.     Question:  Is there a python library that will facilitate solving the following problem:  Given a set of bounding boxes {B}, compute a minimum bounding box C such that for all b in {B}, b is contained in C    , and if not, is there at least a library that can compute this result given lat/lon pairs manually extracted from corner points of these boxes?    Clarity:  I am not concerned about what metrics are used to solve the "minimum" box, whether it be area, boundary differences, etc. As long as it is a reasonable and efficient solution.    Visual:  Input:    Output (red is good, black and purple are bad):    EDIT: I just realized the purple box does not actually make sense here on the flat map (read Logan's comment below). I'm going to leave it for now since the principle still applies to the black box at least.


append %200 at the end of an "address 1.1.1.1" line

I need to add %200 at the end if "address 1.1.1.1". I am using bash on linux if someone can let me know.   Current  ltm node /test/10.90.0.1 {     address 10.90.0.1 } ltm node /test/10.90.0.12 {     address 10.90.0.12 }  ltm node /test/10.90.0.50 { address 10.90.0.50       }   Desired, with insertion of %200  ltm node /test/10.90.0.1 {     address 10.90.0.1%200 } ltm node /test/10.90.0.12 {     address 10.90.0.12%200    } ltm node /test/10.90.0.50 {     address 10.90.0.50%200 }


How can I instantiate a generalized hash function?

I've come across a bunch of "strange" hash function notations, such as the following ones and now I don't know how to choose / instantiate them.  Can you please explain me what this notation means and how I can actually instantiate such a hash function?  The notation in question: $$H_1:\mathcal M \rightarrow \mathbb F_p$$ $$H_2:\mathcal M \rightarrow \mathbb Z_n^*$$ $$H_3:\mathcal M \rightarrow \{0,1\}^l$$ $$H_4:\mathcal M_1\times ...\times \mathcal M_k\rightarrow \mathcal S$$  where $\mathcal M\in\{\mathbb F_p,\mathbb Z_n^*,\{0,1\}^*,\mathbb G,...\}$ where $\mathbb G$ is a generic (but there instantiated) group and $\mathcal S\in\{\mathbb F_p,\mathbb Z_n^*,\{0,1\}^l\}$


Unable to install systemd-container ubuntu 20.04

I tried to install systemd-container on brand new ubuntu 20.04 but I have following message: sudo apt-get install systemd-container Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  systemd-container : Depends: systemd (= 245.4-4ubuntu3) E: Unable to correct problems, you have held broken packages.  But it's not obvious how to fix it because when I try, getting this sudo apt install systemd=245.4-4ubuntu3 Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  policykit-1 : Depends: libpam-systemd but it is not going to be installed  systemd : Depends: libsystemd0 (= 245.4-4ubuntu3) but 245.4-4ubuntu3.2 is to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.  And so one till libpam-systemd sudo apt install libpam-systemd=245.4-4ubuntu3 Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  libpam-systemd : Depends: systemd (= 245.4-4ubuntu3) E: Unable to correct problems, you have held broken packages.  And at this point, we got a circle. EDIT: found that I can $ sudo apt download systemd-container  $ sudo dpkg --force-all -i systemd-container_245.4-4ubuntu3_amd64.deb   And it's working but I got dependency errors all the time. Is there any better workaround? EDIT 2: apt-cache output apt-cache policy systemd systemd-container systemd:   Installed: 245.4-4ubuntu3.2   Candidate: 245.4-4ubuntu3.2   Version table:  *** 245.4-4ubuntu3.2 100         100 /var/lib/dpkg/status      245.4-4ubuntu3 500         500 http://pl.archive.ubuntu.com/ubuntu focal/main amd64 Packages systemd-container:   Installed: (none)   Candidate: 245.4-4ubuntu3   Version table:      245.4-4ubuntu3 500         500 http://pl.archive.ubuntu.com/ubuntu focal/main amd64 Packages         100 /var/lib/dpkg/status  EDIT 3: Quick way to reproduce error on ubuntu 20.04: adam@adam:~/$ systemd-nspawn  Command 'systemd-nspawn' not found, but can be installed with:  sudo apt install systemd-container  adam@adam:~/$ sudo apt install systemd-container Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  systemd-container : Depends: systemd (= 245.4-4ubuntu3) E: Unable to correct problems, you have held broken packages.  Best


What is the relationship between the absolute nature of the speed of light and the indeterminate nature of Heisenberg’s uncertainty principle?  Or to phase it differently, can any of a particle’s many superpositions involve faster than light travel?  To illustrate this point I will use a thought experiment. Imagine a tube exactly 1 light second long. An object moving at very close to the speed of light enters the tube. After 1 second the particle will not have left the tube as it is traveling less than the speed of light, so there’s a distance x remaining for it to travel in the tube. There is also some indeterminacy in its position y.  If the speed of the particle is increased until x is of the same size as y there should be a conflict between the consistency of the speed of light and the uncertainty principle. At some point very close to light speed the indeterminacy of position should breach the light barrier.   is similar but is not asking exactly the same thing. I suspect that the answer is yes some of a particle’s many superpositions can involve faster than light travel. But it would be useful to have this confirmed by someone who understands both quantum theory and relativity.


In Java Edition, I can name a mob by using NBT tags like this: /summon zombie ~ ~ ~ {CustomName:'{"text":"TheUndead"}'}  But in Bedrock Edition, I've heard NBT is not accessible from commands. What can I do to summon a mob with a custom name tag using the /summon command?


Old movie about three boys who make a computer that lets them create a force field that leads them into space

So I'm trying to think of a movie I saw once when I was a kid. I don't know when the movie was originally published but I do know what it was about. The general plot was three boys come together and end up building a computer which allows them to go into space via some type of weird force field bubble. Thing I remember one boy had a father who worked with computers I think, and one boy said he never had dreams before. Does anybody know what movie I'm talking about?


Using OpenJDK and JavaFX for self-contained, modular packaging

EDIT: the tutorial linked in the answer of the duplicated question has gotten me past the problem I wrote about here. I had seen that question earlier and I did not, at the time, think it applied. But I was mistaken and I don't know how to account for the mistake. To install a working copy of a modular OpenJDK and JavaFX, I agree that the "Getting started" tutorial at  is an appropriate resource. /EDIT     I have relatively simple source code that I would like to compile on Ubuntu. The code was developed in Eclipse/Windows, and makes use of JavaFX. My hope was to simply copy over the text source and do a modular compile, with the end goal being to make a self-contained program using jlink for Linux installation. The code is simple enough that the command line commands javac (with the modules option) and jlink are quite sufficient.  I installed OpenJDK 10, figuring that would be fine, as it contains the jlink utility and supports modular programming.   > java -version openjdk version "10.0.2" 2018-07-17 OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4) OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)   I'm able to run Java jars with it, but NOT if they require JavaFX.  > java -jar rnk.jar Error: Could not find or load main class com.adonax.keyboard.LaunchKeyboard8 Caused by: java.lang.NoClassDefFoundError: javafx/application/Application   First attempt to deal with this, I installed OpenJFX with the following command:  sudo apt-get install OpenJFX   AFAIK, it installed fine, but I could not find instructions for testing or verifying the install on any of the Ask Ubuntu or StackOverflow posts that recommend this install. Attempting to run a jar which includes JavaFX code still fails, with the same error.  Using OpenJDK 8 is not a solution. The goal is to be able to use the command line javac and jlink, and Java 8 does not support modules.  I was trying to avoid using Oracle's Java 9 or 10, as suggested in many of the answers I've researched, because as far as I know, Oracle is requiring a license payment  I'm admittedly weak in terms of my Linux & Ubuntu knowledge, and have gotten myself totally confused on how to go forward. Ramping up to the expertise required to build as in  would be a big leap.  I am hoping that these last few lines justifies my question not be marked a "duplicate question."  Is there something simpler that I've overlooked?


Proof that every group of order 30 has a subgroup or order 15

I'm trying to understand this proof that every group of order $30$ has a subgroup of order $15$:  By Example $37.12$, a group $G$ of order $30$ has a normal subgroup of order $5$ or of order $3$. Suppose that $G$ has a normal subgroup $H$ of order $5$. Then $G/H$ is a group of order $6$, which has a normal subgroup $K$ of order $3$ by Sylow theory. If $λ : G → G/H$ is the canonical homomorphism, then $λ^{−1}[K]$ is a normal subgroup of $G$ of order $3 · 5 = 15$. If $G$ has no normal subgroup of order $5$, then it has a normal subgroup $N$ of order $3$, so $G/N$ has order $10$ and has a normal subgroup $L$ of order $5$. Applying to $L$ the inverse of the canonical homomorphism mapping $G$ onto $G/N$ gives a normal subgroup of $G$ of order $15$  First, why the inverse image doesn't have the same number of elements as $K$ since $\lambda$ is a bijection? Also, why the inverse image has $3.15$ elements?


Having trouble solving the following problem:  Prove that any family of pairwise disjoint open intervals is countable.  Any help would be great!


Will we get our reputation back if bounty is not answered in SOF [2019]?

I saw many other old posts which states that we won't get our reputation back but I would like to know whether stackoverflow has added an option for it or not? If there is no feature till now please consider adding that feature.


I am not at all familiar with mathematical proof-writing and would like to learn how to create my own proofs. So, I was wondering whether it would be possible for you to recommend me to any book or site that would introduce me to proof-writing.  Additionally, I would like this source to not be of a very high mathematical level and not be about computer science based proofs.  Thank you :)


This is the table which has different technology with the same id  id   technology        ------------------ 1    MCA            1    BSC SCIENCE    2    BTECH          3    BTECH          3    MTECH     How can I get the output group together as:  id   technology        -------------------------- 1    MCA, BSC SCIENCE                2    BTECH          3    BTECH, MTECH


Substitution $\partial_\mu \to D_\mu \equiv \partial_\mu + ieA_\mu$ allows the introduction of electromagnetic interactions

I want to show that the substitution $\partial_u \to D_\mu \equiv \partial_\mu + ieA_\mu$, or equivalently $p_\mu \to p_\mu - eA_\mu$ allows the introduction of electromagnetic interactions. Here $e$ is the electric charge of the particle in question $($$e=-|e|$ for an electron$)$, and $A^\mu = (\Phi, \vec{A})$ is the vector potential. By converting the Dirac equation in the form$$[\vec{\alpha} \cdot (\vec{p} - e\vec{A}) + \beta m]\psi = (E - e\Phi)\psi$$to a second-order equation, and taking the low-energy limit, show that the interaction with the electromagnetic field gives rise to a change in energy in the presence of a magnetic field $\vec{B} = \nabla \times \vec{A}$ of the form$$\Delta E = -{{e}\over{2m}}\vec{\sigma} \cdot \vec{B}$$and hence implies a value of $g=2$ for the electron's magnetic moment $\vec{\mu}$ defined in terms of its spin $S$ as$$\vec{u} = g\left({e\over{2m}}\right)\vec{S}.$$Progress so far: The Dirac equation is $$(i\gamma^\mu D_\mu - m)\psi = (i\gamma^\mu(\partial_\mu + ieA_\mu) - m)\psi = 0.$$If we take $\gamma^0 = \beta$, $\gamma^i = \beta\alpha_i$, $\partial_\mu = (\partial_i, \nabla)$, and $A_\mu = (\Phi, -{\bf A})$ then we can write this as $$[i\beta(\partial_t + ie\Phi) + i\beta\alpha \cdot (\nabla - ie{\bf A}) - m]\psi = 0$$or, since $\beta^2 = 1$,$$[i(\partial_t + ie\Phi) + i\alpha \cdot (\nabla - ie{\bf A}) - m\beta]\psi = 0.$$I tried some things after this, but they didn't work out. Can anyone give me a step in the right direction?


Cartoon action series with suits that shoot grappling hooks to create ziplines across canyons

There was this 90s team action Cartoon on Cartoon Network back when the Power Zone would play with Swat Cats and Centurions. I just saw a few episodes and I don't think it lasted long. It was similar to the centurions with the protagonists being a large team of guys who would have machines attached to their backs via suits. The machines were the whole length of the person and would allow them to stand in it. The top of the machine would shoot grappling hooks with ropes. The whole cartoon was was set in mountains and canyons and this is how the characters would get across with their individual machines allowing them to zip along the ropeway made by it. Desperate to get the name of this series so that I can just relive a few episodes :)


Expected number of rolls until all die faces have appeared?

Suppose you have a die. On average, how many rolls does it take for all the faces (1 through 6) to have appeared?  Also, what kind of distribution is this?  (I thought of this question when watching rain fall on my driveway; I wondered how long it takes for rain to completely cover the whole driveway.)


How to convert a simple summation into algebraic expression?

I'm trying to simplify a calculation by making a summation an algebraic expression:  $$ \sum_{i=1}^{n} a^i $$  I have no idea how to do this, since when I expand the sum's first few terms it's difficult to find aw simple expression for it, that doesn't expand with $n$.  Any help is appreciated.


how to install OS in pandrive and run on any pc or laptop?

My laptop is currently not being formatted properly.  Every time I try to install any operating system it installs, but before I can move to drive, it crashed and gets back to boot screen, it doesn't even reaches the OS boot menu.  I was wondering If I could be helped to install an OS completely within a pen drive , then access my drives just by connecting my laptop to my pen drive.  Please guide me with this situation, I have some urgent data on one of my drive which I need to recover anyhow.


How does this `Underfull \vbox (badness 10000)` happen?

Perhaps this is a silly question. I got several Underfull \vbox (badness 10000) in my document, and to find the reason, I simplified the code all the way to \documentclass{book} \usepackage{geometry} \linespread{1.25} \usepackage{blindtext} \begin{document} \blindtext[10] \end{document}  And the problem remains: Underfull \vbox (badness 10000) has occurred while \output is active [1] [2]  Is there any way to solve this?


Would I notice the difference between a 7200 rpm and a 5400 rpm laptop hard drive?

During real, everyday use, that is?  I'm looking to upgrade a drive in a MacBook Pro, and am looking at either a 750GB/7200RPM or a 1TH/5400RPM drive.  Would I care about the speed difference? Is it worth giving up the additional space on the larger drive?


Let's make the hot network questions icons clickable

I would like to see the icons in the 'Hot Network Questions' right panel clickable, leading to the homepage of the site where the question comes from.  It would make it more comfortable to switch to the site when you want rather to visit it than to see that specific "hot" question.


Append an element to particular list within a list - Python


How do "stats changes if equipped" work in Diablo 3?

I am a little confused by this preview of the damage that could be done in Diablo 3  Dire Span is reporting to give me +1076 to damage.  When equipped however it in fact reduces my overall dam by nearly 1.5k.  So how is this calculated? Is it only a problem because of the % that is added on these weapons to the damage when strength is taken into account?   Whilst this question may appear similar to this:   However this question does not give information on strength factor.


Find foci and eccentricity of ellipse given either 5 points or its general equation

I'm considering an arbitrary, non-degenerate ellipse here, i.e., without assuming that it's centred on the origin or either axis, nor oriented at any specific angle.  I know either 5 points on the perimeter $(x_1,y_1)$ through $(x_5,y_5)$, or the general cartesian equation $Ax^2+Bxy+Cy^2+Dx+Ey+F=0$ where $F = 0$ or $1$.  The two forms are equivalent as it's easy to solve the simultaneous equations for 5 values of $(x,y)$ to get $A$ through $F$ when the ellipse isn't degenerate. These uniquely define one ellipse - or a conic at any rate ;-)  But what I'm really after are the cartesian foci and its eccentricity (I can get everything else I might need from these: the major/minor axes, rotate the ellipse to align with the axes, or find its equation in polar form if needed).   I can't find a way to do that......


What are the colored/highlighted edges in edit mode?

There are red and pink edges on my mesh.  What do these colored edges mean? How can I use them?


Is there a way to re-ask or refresh a question?

I have just run across a question on Stack Overflow that was asked and answered last year.    The answer to this question is time-sensitive in the fact that if the same question was posed today, it may receive a different answer.  It would be interesting to see a feature that allowed you to fire a request (probably with a limit of one request per 6-12 months per question) to have each answerer of a question indicate whether or not they still stand by the answer they provided.  Is there an already established etiquette for re-asking a question?


Why aren't solenoid/electromagnet windings insulated?

This has been bugging me for a long time. Take  for example.  I have always thought that electricity will take the shortest path. When the electromagnet's windings are uninsulated, it seems that the electricity would flow straight through the "mass of metal" created by the wire, not in the circular path needed for the electromagnet to work. I have also seen solenoids that work like this. How does this design work?


Cross Referencing not referring bibliography in elsarticle

I am working on a paper for Elsevier, but the cross reference is not referring to bibliography , as it appear disabled . My code is here   \documentclass[preprint,3p,twocolumn]{elsarticle}   \usepackage{lineno}          \usepackage{pifont} \usepackage{natbib} \usepackage{graphicx} %\usepackage{cite} \usepackage[nodots,nocompress]{numcompress} \usepackage{setspace}   \journal{Computer Networks}   \begin{document}  \begin{frontmatter}    \title{Wireless Sensor Networks Routing: Key Challenges and Open Issues}   \author[a]{Palvinder Singh Mann\corref{cor1}} \ead{psmaan@hotmail.com} \author[b]{Satvir Singh} \ead{satvir15@gmail.com} \cortext[cor1]{Corresponding author.Tel.:+91-9888395367 fax:+91-0181-2205852}  \address[a]{Department of Information Technology, DAV Institute of Engineering and Technology, Jalandhar,Punjab,India.144008.} \address[b]{Department of Electronics and Communication Engineering, Saheed Bhagat Singh State Technical Campus, Ferozepur, Punjab, India.152004.}  \begin{abstract} Wireless sensor networks (WSNs) enable new applications and require non-conventional paradigms for protocol design. Owing to the requirements for self-organization, scalability and primarily low energy consumption needs, a proper balance between communication and data processing capabilities must be maintained. This motivates a huge effort in research activities and investments on this field for past few years. At present most of the research on WSNs has concentrated on the design of energy and computationally efficient algorithms and routing protocols with application domain restricted to simple data-oriented monitoring. In this paper, we presented a comprehensive analysis on WSNs routing with key challenges for development of protocol designs. At last we discussed some open issues for future directions in WSNs for research contributions. \end{abstract}  \begin{keyword} Wireless sensor networks, self-organization, scalability, routing protocols   \end{keyword}  \end{frontmatter}  \linenumbers  %% main text  \section{Introduction}   Wireless Sensor Networks (WSNs) contain self-configured, distributed, autonomous and resource empowered sensor nodes that monitor physical or environmental activities, such as humidity, temperature, sound, vibration or pollutants in a specific area of operation\cite{akkaya2005survey}. Sensor nodes \cite{abbasi2007survey}cooperatively \cite{al2004routing}pass their sensed data through the wireless\cite{bi2010ant} network to a main location, known as sink or base station where the data can be monitored and analyzsed for decision making.   \subsection{Subsection One}    \subsection{Subsection Two}    \section{References}   \bibliographystyle{model1-num-names} \bibliography{Ref}     \end{document}


How to make a 'D' shape out of circles (that follow the curved path)?

I am creating a logo for an NGO and it must contain the letter 'D'. They've required it to be similar to this one:       How do I go about making the circles follow the 'D'-shaped path? I know how to make it such that the circles are cut off, but my client doesn't want that. Any help is appreciated.


i'm trying to use the  package  \usepackage{titlepages}   but TeX Maker gives me this error:     ! LaTeX Error: File `titlepages.sty' not found. Type X to quit or    to proceed, or enter new name. (Default extension: sty)   On Ubuntu 16.04, i install the following but the error still happens:  sudo apt-get install texlive   Please help.


Reverse Markov Inequality for non-negative unbounded random variables

I need to lower bound the tail probability of a non-negative random variable. I have a lower bound on its expected value. I am aware of a reverse markov's inequality that does the job when the random variable is bounded above. Unfortunately that is not my case.   Is there any other inequality that may be useful to me in this regard?  thanks  NR


Is it neccessary to unsubscribe eventhandler of an owned object?

It's important to mention that the question is about an owned object which its lifecycle will be controlled by the container it is declared in.   For an external object which has been assigned from outside which lifecycle is not controlled by the container class, it is neccessary to unsubscribe its event handler when the class will be disposed/destroyed to avoid memory leaks.   public class ContainerClass: IDisposable {     private INotifyPropertyChanged SomeNotifyObject = new SomeNotifyPropertyChangeedImplementingClass();      public ContainerClass()     {         SomeNotifyObject.PropertyChanged += SomeNotifyObjectOnPropertyChanged;     }      // Neccessary if ContainerClass OWNS the subscribed object?     void IDisposable.Dispose()     {         SomeNotifyObject.PropertyChanged -= SomeNotifyObjectOnPropertyChanged;     }      private void SomeNotifyObjectOnPropertyChanged(object sender, PropertyChangedEventArgs e)     {         // Stuff     } }   If the anser is no, it is not neccessary in case of an owned object, code could be written less complex:  private INotifyPropertyChanged SomeNotifyObject = SomeNotifyPropertyChangeedImplementingClass();      public ContainerClass()     {         SomeNotifyObject.PropertyChanged += (sender, args) =>         {             /* Call whatever you want */         };     } }


Determine the number of irreducible monic polynomials of degree 3 in $\mathbb F_p[x]$ where $p$ is a prime.  I'd like to start off by acknowledging that I know there are many posts relating to similar problems both on here and mathoverflow, however none address my problem.  In class, my professor went over the monic polynomials of degree 2 by reasoning that there are $p^2$ distinct polynomials, the reducible ones look like $(x - a)^2$ and $(x - a)(x - b)$ for the first one there are $p$ of them and for the second one there are $p(p-1)/2$ of them, subtracting the reducible ones from the total ones gives $$p^2 - p - \frac{p(p - 1)}{2} = \frac{2p^2 - 2p - p(p-1)}{2} = \frac{2p^2 - 2p - p^2 + p}{2} = \frac{p^2 - p}{2}.$$  I'm trying to use similar reasoning for polynomials of degree three using the fact that there are $p$ irreducible monic linear polynomials and $p(p-1)/2$ irreducible monic quadratic polynomials. But I can never get the result shown  and .  My reasoning is as follows: Observe that reducible polynomials would look like $(x - a)(x - b)(x - c)$, $(x - a)^2(x - b)$, $(x - c)^3$ and $(x^2 + ax + b)(x - c)$ formed from irreducible linear and quadratic monic polynomials.    For the first type where all three are distinct we can surmise that there are $p$ choices for the first, $p-1$ choices for the second and $p - 2$ choices for the third. So we have $p(p-1)(p-2)$. (is it $p$ choose $3$? Do I have to account for order not mattering?) For the second type there are $p$ choices for the square, and $p-1$ choices for the linear polynomial, so we have $p(p-1)/2$. For the third type, we have shown that there are $p(p-1)/2$ choices for the quadratic polynomials and there are $p$ choices for the linear polynomial. So we have $p^2(p-1)/2$.   Subtracting these values from $p^3$ should give me what I'm looking for, which is $p(p^2 - 1)/3$. But I'm not getting that.  Can someone tell me where my reasoning is wrong? Or tell me how to go about counting the number of irreducibles? (I know there are other methods of getting the answer, even more general ones, but I'm looking for a simple counting method that can help me better understand where my reasoning is wrong and help me correct it.)


Hello I am having a some difficulty with a very simple program.  import java.util.*; public class Compare {     public static void main( String args[] )     {          String username;          Scanner input = new Scanner(System.in);          String users[] = {"John", "James", "Smith", "Paul"};           System.out.println("Please Enter Username: ");          username = input.next();           for( int i = 0; i < users.length(); i ++ )          {                if( users[i] == username )                   System.out.println("Match");                else                   System.out.println("No Match");          }     } }   When I run this program I get No Match which I don't know how is possible when I enter the same string as on of the strings in the users array. Any Suggestions?


Continuous bijective function between the same topology that is not a homeomorphism.

I know there are many examples when the domain and co-domain do not coincide. Taking the identity on $X$ from $(X,\tau_1)$ to $(X,\tau_2)$ when $\tau_2$ is coarser than $\tau_1$ gives an infinite family of examples.  However I have been struggling to find an example of such a function between the same topology. I came to think about this because in $\mathbb R$ any bijective continuous function is a homeomorphism.  Thank you in advance, regards.


[2.] a. {intransitive} To deal with some matter in speech or writing; to discourse. (In quot. 1517   transf. of pictorial representation.) Const. of, formerly also on, upon    What are the similarities and differences? Which definition of  fits? Is of a preposition or a particle?   I encountered this verb phrase below, but notice that the quoted clause with the bold originates from OED's entry on the suffix .           word-forming element meaning "a speaking, discourse, treatise, doctrine, theory, science," from Greek -logia (often via French -logie or Medieval Latin -logia), from root of legein "to speak;"  thus, "the character or deportment of one who speaks or treats of (a certain subject);" see  (n.).


How to display KDE lock screen time in 24-hour format

Running Kubuntu with the Plasma desktop, 16.04.   I have my desktop configured to 24-hour time, which is what I vastly prefer.   But when the lock screen comes on, it shows me the detested AM/PM format. This cannot stand. Yet after diligent searching, I am unable to find a solution.   Is this configurable in KDE?


Why doesn't the huge difference between the muggle and wizard gold exchange rates get misused?

Why doesn't the huge difference between the muggle and wizard gold exchange rates lead to the collapse of the wizard economy?  We know, that 17 silver Sickles is worth a golden Galleon. However, in the muggle world, you can get more than 50 kg silver for one kg of gold.   Even if Sickles were the same size as Galleons (if I remember correctly, they are much smaller), and the gold content of Galleons was the same or even less than typical muggle gold coins, it would still be highly profitable, to buy silver in the muggle market, exchange it for gold in the wizard market, and sell the gold in the muggle market.  How is it that no one does it? It could ruin the wizarding economy in a very short time, or at least draining most the gold out of it and altering the exchange rates between Galleon and Sickle?  We all know that magic can't create money or precious metals...


What exactly is Characteristic impedence in transmission lines?

Please help me to understand what does a characteristic impedance mean. I am unable to get the exact idea of what does it actually mean and its physical significance.


How can I detect when a player breaks a mob spawner?

I am working on a map that I want to test if a player breaks a spawner. Then it gives the player a spawner, and maybe some XP. I want to use a scoreboard command, but /scoreboard objectives add SB stat.mineBlock.minecraft.mob_spawner doesn't work even though the spawner ID is mob_spawner. What is the correct way to write this?  (Forgot: I need it to be any spawner, natural or placed :P )


Find Total number of ways out of N Number taking K numbers every M interval

I have been stuck in a problem, that has thrown my brain out of the coding. This problem is at very high priority and I need the solution as early as possible. Problem is as :  There are exactly N advertising boards on the highway. Now a company want to advertise on some of these advertising boards(each advertising board costs some money) .  Company strategy is that, they want at least 'K' advertisement should be there among M consecutive advertising boards. But at the same time Company want to pay minimum for its advertisement .  Now, what is the total number of ways, different ways Company can advertise meeting its minimum cost strategy.  As for Example: N= 3, M = 2, K=1 ==> there is only one way for minimum cost, ie. 0C0 , where '0' denotes No company advertisement, and 'C' denotes company advertisement board.  Similarly, for N =4, M =2, K =1 ==> there is 3 possible ways, ie. C0C0, 0C0C, 0CC0.  Hope to get a reply from someone soon. Thanks.