I am a noob to linux.  I tried the following commands:  sudo bootnukem  sudo apt-get autoremove  dpkg -l linux-{image,headers}-"[0-9]*" | awk '/^ii/{ print $2}' | grep -v -e uname -r | cut -f1,2 -d"-" | grep -e '[0-9]' | xargs sudo apt-get -y purge  Problem is  sudo apt-get autoremove Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  linux-image-generic-hwe-16.04-edge : Depends: linux-image-4.15.0-43-generic but it is not installed  linux-image-virtual-hwe-16.04-edge : Depends: linux-image-4.15.0-43-generic but it is not installed  linux-modules-extra-4.15.0-43-generic : Depends: linux-image-4.15.0-43-generic but it is not installed or                                                   linux-image-unsigned-4.15.0-43-generic but it is not installed E: Unmet dependencies. Try using -f.   When tried to install it fails with no space issues.  :~/bootnukem$ sudo apt-get -f install     Reading package lists... Done     Building dependency tree            Reading state information... Done     Correcting dependencies... Done     The following additional packages will be installed:       linux-image-4.15.0-43-generic     Suggested packages:       fdutils linux-hwe-tools     The following NEW packages will be installed:       linux-image-4.15.0-43-generic     0 upgraded, 1 newly installed, 0 to remove and 181 not upgraded.     7 not fully installed or removed.     Need to get 0 B/7.898 kB of archives.     After this operation, 8.141 kB of additional disk space will be used.     Do you want to continue? [Y/n] y     (Reading database ... 511782 files and directories currently installed.)     Preparing to unpack .../linux-image-4.15.0-43-generic_4.15.0-43.46~16.04.1_amd64.deb ...     Unpacking linux-image-4.15.0-43-generic (4.15.0-43.46~16.04.1) ...     dpkg: error processing archive /var/cache/apt/archives/linux-image-4.15.0-43-generic_4.15.0-43.46~16.04.1_amd64.deb (--unpack):      cannot copy extracted data for './boot/vmlinuz-4.15.0-43-generic' to '/boot/vmlinuz-4.15.0-43-generic.dpkg-new': failed to write (No space left on device)     No apport report written because the error message indicates a disk full error                                                                                dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)     /var/lib/dpkg/tmp.ci/postrm ... removing pending trigger     Errors were encountered while processing:      /var/cache/apt/archives/linux-image-4.15.0-43-generic_4.15.0-43.46~16.04.1_amd64.deb     E: Sub-process /usr/bin/dpkg returned an error code (1)   My version   uname -a Linux NB128 4.15.0-39-generic #42~16.04.1-Ubuntu SMP Wed Oct 24 17:09:54 UTC 2018 x86_64 x86_64 x86_64 GNU/Linu   Any help is greatly appreciated.

My /boot partition is nearly full and I get a warning every time I reboot my system. I already deleted old kernel packages (linux-headers...), actually I did that to install a newer kernel version that came with the automatic updates.  After installing that new version, the partition is nearly full again. So what else can I delete? Are there some other files associated to the old kernel images?  Here is a list of files that are on my /boot partition:  :~$ ls /boot/ abi-2.6.31-21-generic         lost+found abi-2.6.32-25-generic         memtest86+.bin abi-2.6.38-10-generic         memtest86+_multiboot.bin abi-2.6.38-11-generic         System.map-2.6.31-21-generic abi-2.6.38-12-generic         System.map-2.6.32-25-generic abi-2.6.38-8-generic          System.map-2.6.38-10-generic abi-3.0.0-12-generic          System.map-2.6.38-11-generic abi-3.0.0-13-generic          System.map-2.6.38-12-generic abi-3.0.0-14-generic          System.map-2.6.38-8-generic boot                          System.map-3.0.0-12-generic config-2.6.31-21-generic      System.map-3.0.0-13-generic config-2.6.32-25-generic      System.map-3.0.0-14-generic config-2.6.38-10-generic      vmcoreinfo-2.6.31-21-generic config-2.6.38-11-generic      vmcoreinfo-2.6.32-25-generic config-2.6.38-12-generic      vmcoreinfo-2.6.38-10-generic config-2.6.38-8-generic       vmcoreinfo-2.6.38-11-generic config-3.0.0-12-generic       vmcoreinfo-2.6.38-12-generic config-3.0.0-13-generic       vmcoreinfo-2.6.38-8-generic config-3.0.0-14-generic       vmcoreinfo-3.0.0-12-generic extlinux                      vmcoreinfo-3.0.0-13-generic grub                          vmcoreinfo-3.0.0-14-generic initrd.img-2.6.31-21-generic  vmlinuz-2.6.31-21-generic initrd.img-2.6.32-25-generic  vmlinuz-2.6.32-25-generic initrd.img-2.6.38-10-generic  vmlinuz-2.6.38-10-generic initrd.img-2.6.38-11-generic  vmlinuz-2.6.38-11-generic initrd.img-2.6.38-12-generic  vmlinuz-2.6.38-12-generic initrd.img-2.6.38-8-generic   vmlinuz-2.6.38-8-generic initrd.img-3.0.0-12-generic   vmlinuz-3.0.0-12-generic initrd.img-3.0.0-13-generic   vmlinuz-3.0.0-13-generic initrd.img-3.0.0-14-generic   vmlinuz-3.0.0-14-generic   Currently, I'm using the 3.0.0-14-generic kernel.


I wanted to put an image from a company onto my 3D model. How would I do this with blender cycles? I have the image file and I want to put it on the torso of my character (which is about 4 faces put together) I would really appreciate any help!

I'm trying to setup a image decal in cycles, and I can't figure how to setup the nodes to work fine. Does anyone know the solution?


I used this command: sudo apt update  to update my packages on Ubuntu, but it shows the errors below: Err:13 http://archive.ubuntu.com/ubuntu disco Release  404  Not Found [IP: 91.189.91.38 80] Err:14 http://archive.ubuntu.com/ubuntu disco-updates Release   404  Not Found [IP: 91.189.91.38 80] Err:15 http://archive.ubuntu.com/ubuntu disco-backports Release   404  Not Found [IP: 91.189.91.38 80] Err:16 http://archive.ubuntu.com/ubuntu disco-security Release   404  Not Found [IP: 91.189.91.38 80] Reading package lists... Done  Here is the screenshot:

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


I was on Politics just now, and noticed :    On my screen, it appears that they are wearing both Where in the World? and Warm Welcome at the same time.  When I try to equip hats, however, there seems to be a one-per-user limit for use of them.  What's up here? Is this a glitch, or is there a way to equip two hats that I just don't understand?

I earned two hats on a site, and I think it would be great if we can wear both at the same time.  Can this please be made possible?


I always have a doubt that how do firmware engineers dump code into a quad flat microcontroller(with or without leads)? For a starter kit there is already connection like USB or some SPI ,I2C headers to burn the code. I know that for Dual inline Package there are some programmers in the market.Then what about quad flat micros used in industrial application?How do you all proceed?

I have broken open a few circuits of some electronics (DVD player, handheld game device) and I can see the microcontrollers in them. However, I have no idea how they get their programs onto them! There is no micro usb or usb plug anywhere on them! How would they have gotten their program onto there?


I don't quite understand. How can some academics after hundreds of years of research on, say, Plato, still come up with novel, publishable interpretations, ideas, readings, solutions to these texts?  Plato is a good example for this, I think. But i am generally confused how this works, and how people can still come up with new ideas all the time.  Doesn't it get more difficult after some time?

As a very new researcher who is exploring the best way to generate ideas, some guidance on this question would be very helpful. I have found that this is NOT easy. Ideas seem to pop out of my Professor every day and I wonder how he does it. This question is broad;   How do you tend to come up with initial/seed ideas? What is your search method (if you have one)? What proportion of your ideas for past papers come from; (i) colleagues, (ii) intentionally browsing the literature for ideas, (iii) on the spot inspiration, (iv) conferences, (v) other? How do you prioritize research ideas? Is there any special, generalizable method that you've discovered to sift out those ideas that are likely to be unrealistic early on in the process of idea generation?   Based on small amounts of anecdotal evidence I have reason to believe that there is vast heterogeneity among professors regarding the above questions. For example, economist Steven Levitt says he works on 22 papers at once. A professor I know will have maybe 25% of this at any one time.  Related but not duplicate:


I charged my 2016 13"   this morning with a 24W solar panel.  I am not sure if this is safe to do longterm for the the laptop. Am I damaging the MacBook if I do this? What would happen if I used a 60W solar panel?

This question pertains to USB-C not MagSafe. MagSafe negotiates available power with the . USB Power Delivery (PD) is an unrelated protocol. Answers based on experience with MagSafe are unlikely to be relevant.  I'm considering buying a 2016 MacBook Pro Retina about which :     the Griffin product was only powerful enough to offer 60W of power, not quite enough for the 87W needed to power the larger Pro models at fully   I'm also considering buying a  which it advertised as providing:     Mobile / Laptop Charging Up to 60W   What are the consequences of using a 60W supply instead of an 87W one?  Does it just mean it will take longer to charge the laptop?  Could it have side effects such as putting parts of the system into a slower, low-energy mode?   covers MagSafe power supplies but Charles Duffy's comment suggests that the rules for USB-C may be different.


Here is my example scenario:  I have a WIN 7 Pro computer with 3 different accounts; John Jack James  This computer sits on a desk on it's own and users RDP on to the machine.  James is already RDP'd on to the machine on his own profile John wants to RDP on to the machine and login with his profile  John wants to use mspaint and draw something James is already RDP'd on and is using excel.  Is it possible for John to RDP on to the same machine and do whatever tasks he needs whilst James is currently on the machine too.  I'm aware this will involve some dll hacking however is the above possible?  Thanks in advanced.  Can what I am asking be achieved using the machine to run 3 virtual machines, then RDP on to the individual Virtual Machines?  Thanks

In Vista you could copy the 2k8 server .dll for remote desktop and it would let you use remote desktop on the computer without logging off the active user.  Does this work for Windows 7? Has anyone tried?


Is there an easy way to convert a 1D list into a 2D list with a given row length?  Suppose I have a list like this:  myList =  [1, 2, 3, 4, 5, 6, 7, 8, 9]   I want to convert the above list into a 3 x 3 table like below:  myList = [[1,2,3],[4,5,6],[7,8,9]]   I know I can accomplish this by creating a new 2D list called myList2 and inserting the element into MyList2 using 2 nested for loops. Like MyList2[x][y] = myList[i] i++  I think there should be a better way to do it (without using external libraries or modules)  Thanks!

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I found  which was a direct duplicate of .   So I cleaned up the original and voted to close the duplicate. Unfortunately, he then proceeded to delete the question I just cleaned up. Annoyed, I told him he shouldn't have done that. And as a result he seems to have undeleted the original.   Now it does seem that the close votes have been reset. Either that, or I no longer have an indicator that the question currently has a close vote. Trying to vote once again shows me I can't do so because I already voted on the question.   Is this expected behaviour? Or are we dealing with a bug here?

I voted to close  as a duplicate of  (now deleted, after being closed as off-topic and voted down to -6), so did one other user. The author of both questions deleted the earlier one, and now the later question has gone from two close votes to zero. This makes a certain amount of sense (it's no longer a duplicate), but I can't cast another vote even though my original vote is gone. This is troubling for a few reasons:   The original post was closed as off-topic; I can no longer cast a close vote against the new post as off-topic, even though it's a duplicate of an off-topic question (my close vote is effectively lost) Users can abuse this to swallow a certain number of close votes while spamming the same question into the system (as has just unintentionally happened with the above two questions)   Is this a feature or a bug? Was my close vote supposed to vanish, and afterwards am I supposed to be unable to cast a second close vote for the next-best reason?


it should be a quite standard demand.   load data from a database (in this case PostGis) add data to the layer (in this case points with attributes) save new data back to database   I use this functionality with google maps api, but I wan't to move to Openlayers (3/4). Does anyone know a good example, tutorial how i could implement this?

I have read in OpenLayers how to load KML, GeoJSON etc. vector files in OpenLayers. But how can I connect to PostGIS data. If not, why should I upload my data to PostGIS then instead of directly putting my data using WebServices. Am I missing anything?   And I want to load this vector data so that one can see the attributes by clicking on the features.  I need PostGIS because in future I want to enable queries. I think it's only possible by maintaining a database like PostGIS. But how using OpenLayers?   I have read OpenLayers Beginner's Guide, but nowhere it is mentioned. Please help!!


When I click on the button ADD, I got the following error: The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine. I have no clue how to fix this. My operating system is Windows 8.1.

I have a Visual Studio 2008 solution with two projects (a Word-Template project and a VB.Net console application for testing).  Both projects reference a database project which opens a connection to an MS-Access 2007 database file and have references to System.Data.OleDb.  In the database project I have a function which retrieves a data table as follows   private class AdminDatabase    ' stores the connection string which is set in the New() method    dim strAdminConnection as string     public sub New()    ...    adminName = dlgopen.FileName    conAdminDB = New OleDbConnection    conAdminDB.ConnectionString = "Data Source='" + adminName + "';" + _        "Provider=Microsoft.ACE.OLEDB.12.0"     ' store the connection string in strAdminConnection    strAdminConnection = conAdminDB.ConnectionString.ToString()    My.Settings.SetUserOverride("AdminConnectionString", strAdminConnection)    ...    End Sub     ' retrieves data from the database    Public Function getDataTable(ByVal sqlStatement As String) As DataTable         Dim ds As New DataSet         Dim dt As New DataTable         Dim da As New OleDbDataAdapter         Dim localCon As New OleDbConnection           localCon.ConnectionString = strAdminConnection          Using localCon             Dim command As OleDbCommand = localCon.CreateCommand()             command.CommandText = sqlStatement             localCon.Open()             da.SelectCommand = command             da.Fill(dt)             getDataTable = dt         End Using      End Function End Class   When I call this function from my Word 2007 Template project everything works fine; no errors. But when I run it from the console application it throws the following exception     ex = {"The 'Microsoft.ACE.OLEDB.12.0'   provider is not registered on the   local machine."}   Both projects have the same reference and the console application did work when I first wrote it (a while ago) but now it has stopped work.  I must be missing something but I don't know what.  Any ideas?


On my server many users performing complex queries using tempdb. Sometimes a failed specifying boundary values obtained are very large tables.   So I want to know who created this temporary table.   When I do:   select * from tempdb.dbo.sysobjects where xtype = 'U' order by name    I get the names of the tables like this:   # tablename__________000000004EB1   How to determine the SPID user who created this table.

We have a SQL Server 2005 database the temp database has become full. By going into SQL Server Management Studio I can see all the temporary tables in the tempdb. Is it possible to tell which session is holding which temp table? Ideally a query which would list temp tables used by each session.  Thanks,


When asking someone what should I say?      Do you have an account on  facebook?     Do you have an account in facebook?    I can simply ask- ''Do you have a facebook account?''  But I'm asking should I use on or in .

What's the difference between say:     "The project will be on GitHub",      "The project will be in GitHub" and      "The project will be at GitHub"?


So let me start off by saying that I'm a complete beginner at Linux in general. I wanted to install Ubuntu along Windows 10 to learn slowly. I did this by booting off of a flash drive, but I made the mistake of thinking when it said it would replace everything, that it meant just on the flashdrive. So after managing to remove my entire OS (thankfully there was nothing important on my hard drive), I need windows back so I can sucessfully install Ubuntu on the side.   Now I have a windows 10 iso on a flash drive, and when I go to install it apparently, I somehow have a FAT32 hard disk now, which in result I get a prompt stating that I can't install windows to fat32.  I can't seem to find many articles on what to do because I'm unsure whether I have to completely wipe my HDD or if there's an easy solution to this. Any guidance someone can help me out with will be greatly appreciated!

I have Ubuntu on my laptop. Now I want install Windows 7 in a dual-boot. How can I do this? I can't lose my Ubuntu files, and I'm afraid that I might break . Go  for UEFI only!


this happens every time i load it, but i dont know how to fix it.  16:00:53    launcher    Preparing to launch minecraft client for 1.8.9   16:00:53    launcher    Checking installations.   16:00:53    launcher    Minecraft client 1.8.9 is ready to start.   16:00:53    launcher    Starting!   16:00:55    launcher    Using default game log configuration client-1.7.xml (outputs XML)   16:00:57    ave Setting user: ASUfan   16:00:57    ave (Session ID is token:4918f14dc0964316b0c451978a27eed3:9b055a259386464cb70d5f589d9e008c)   16:00:59    ave LWJGL Version: 2.9.4   16:00:59    ave Couldn't set pixel format org.lwjgl.LWJGLException: Pixel format not accelerated         at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelFormat(Native Method)     at  org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat(WindowsPeerInfo.java:52)     at org.lwjgl.opengl.WindowsDisplay.createWindow(WindowsDisplay.java:247)     at org.lwjgl.opengl.Display.createWindow(Display.java:306)     at org.lwjgl.opengl.Display.create(Display.java:848)     at org.lwjgl.opengl.Display.create(Display.java:757)     at ave.ap(SourceFile:521)     at ave.am(SourceFile:363)     at ave.a(SourceFile:310)     at net.minecraft.client.main.Main.main(SourceFile:124)

Similar to  on the bugs in Minecraft, I would like a complete list of what error codes exist in Minecraft and how they occur, as well as how they can be resolved.


for some reason my mesh is only visible as a wireframe. I would like to get it back to a solid or textured view. Any suggestions?

I'm new to Blender and this site, so I apologize in advance if I'm not following any of the proper etiquette.  I'm no artist, but I'm trying to learn Blender so that I have some programmer art for me to work around in Unity.    I followed a tutorial for making a basic human model, I rigged it with rigify, and now I'm starting to export it following yet another tutorial.  The thing is, when I was trying to rig the model, I couldn't get the model to go transparent so that I could see the bones inside the model.  Eventually, I managed to get it into wireframe mode, but I can't get it back into solid mode.    It's probably just a display thing and not a property of the model itself, but I want to be sure.  I'm looking at the display options under the "Figure" pane in Blender, and none of the Display check boxes are checked, including the one that says "Wire".  I don't want to import a plain wireframe model into Unity, and even if that doesn't happen, this is functionality of Blender that I should really know anyway, so I'd appreciate any help that anyone has to offer.  If necessary, I can upload the .blend file, but I'm not sure what site people would prefer that I upload it to.


Using QGIS 2.4, I want to create 1,000m buffer around an object, but when I enter 1,000 as the distance I get something that looks more like a 100,000m buffer.    I can enter 0.01 to get what looks like a 1,000m buffer, but I would rather work in single metres.   How do I change the settings so that the number I enter is in single metres?

I am using QGIS. I am aware there is a similar question here but the solution (changing the layer CRS) is not working for me. I cannot change my CRS as I am using information for the entire Asia-Pacific region. Is there another option to create a 1000 km buffer zone from all volcanoes in the region? It is currently projected as geographic coordinates, the default WGS:84.


What if the epsilon-delta definition of a limit reversed the wording for $δ$ and $ϵ$: “for all $δ>0$, there exists an $ϵ>0$ such that, if  $0<|x-a|<δ$, then  $|f(x)-L|<ϵ$.” Would this definition still capture the concept of limit? Why or why not? If not, give a counter-example.  I want to say "no" this doesn't capture a limit because the definition of a limit must hold true for each and every epsilon. However, I'm not quite sure how to state this or what might be a counter-example.

Can anyone please give an example of why the following definition of $\displaystyle{\lim_{x \to a} f(x) =L}$ is NOT correct?:  $\forall$ $\delta >0$ $\exists$ $\epsilon>0$ such that if $0<|x-a|<\delta$ then $|f(x)-L|<\epsilon$  I've been trying to solve this for a while, and I think it would give me a greater understanding of why the limit definition is what it is, because this alternative definition seems quite logical and similar to the real one, yet it supposedly shouldn't work.


I use the document class "book(more font sizes)", with French language. Tables appear as "Table" in the pdf. I tried \renewcommand\tablename{TABLEAU} in the preamble, but even if it does not generate an error, it does not work neither.

I am completely noobie in LaTeX. I need to change table name in all captions. But when I write \renewcommand\tablename{newname} at the beginning of document, it doesn't do anything. It's still "Table" My code looks like this:  ... \renewcommand\tablename{new} ... \begin{table}[b] \centering \begin{tabular}{|l|} ... your table ... \end{tabular} \caption{This table shows some data} \end{table} ...   What am I doing wrong?


I use hibernate every day. Recently (without any conscious change from me) it stopped working. Whenever the computer is supposed to hibernate, it only locks the computer. Clicking hibernate, pressing the power button and (worst) low battery all have the same effect.  I don't even know how to trouble shoot this situation. Sleep works. hiberfil.sys exists. Hibernation is in the list of choices for the power button.  This happens always, even directly after a reboot.   edit: since i dont know how to format in comments:  C:\Windows\system32>bcdedit /enum all The boot configuration data store could not be opened.  The configuration registry database is corrupt.   edit: i was told to try bootrec /rebuildbcd. this doesnt exist in regular or safe mode, but according to google in repair mode. so i booted into that mode, it detected on its own that there's a problem and asked, if i wanted to fix it. i clicked yes, and now hibernate works again.  edit: apparently, my question is kind of a duplicate of:

My Windows 7 (x86, Pro) laptop no longer hibernates. When I tell it via power button or "shutdown /h /f" it fades out the screen to black, but doesn't do anything else. Doesn't even go into a sleep state. Hitting a key pops the screen back on.  I've tried disabling and reenabling hibernation to clear the hiberfil.sys, but it makes no difference. If hibernation is disabled, sleep works fine.  This problem started happening immediately after swapping hard drives. I used Ghost 14 to restore a backup to a new drive then plugged it in. Windows wouldn't boot (BOOTMGR problem) so I ran a repair from the Win7 disc. It's been working fine since, aside from inability to hibernate.  Nothing is showing up in the event log that seems new or relevant.  Any ideas on how I can diagnose or resolve this?


is there a way using sed and awk to search for every last (by spaces seperated) field of a line (in a file), matching a search value (without touching the other fields even if string is matched in a field before the last one), and can that searched value be changed with an other value? 210983342900 342832423-1 i2301rw1900 309212dw90 900 9328423ABC 32091840-943543-9435 3012=32193900 301 3029432 334 210983342900ABCDE 342832423-1 i2301rw1900 309212dw90 900 9328423 32091840-943ABC3-9435 3012=32193900 301 3029432 ABC 3843209898 48435843098543098543 43985439859209438543 499 ABC  So search for ABC at every last field, and change every found value to DEFG or search for 900 at every last field and change it to 000 Can you guys break down and explain the solution?

I have a format looking like this: 983243 woiewewrsadhjf 234 093111 srewdslkjfdgdsdsf 111  Can i use sed to search for all instances of text in the third field and change only those while leaving other third fields as is? So searching for 111 in the third field, changing all third fields containing 111 into othertext, wile leaving other third fields (such as 234) as they are. If possible can you guys break down the solution so I can get educated on how the command is formed. I am here to learn.


I'm very new to Ubuntu and Code so apologies if some stuff isn't understandable. I was trying to run a file after building it in a IDE (Code::Block) and the file popped up as this:  The program was a very simple Hello World program that looks like this: using namespace std;  int main() {    cout << "Hello, world!" << endl;    return 0; }```

I have written a C++ program and complied it to produce a.out file. However, whenever I try to run it, I get Permission Denied. I read that we can use sudo, but I can't quite get it to work. I use something like, sudo "./a.out" but that too doesn't work.  Edit:  Here is the message I get when I try "./a.out".  bash: ./a.out: Permission denied


We have an urn with $17$ balls, $3$ are green, $4$ are blue, $5$ are red and $5$ are brown. We take balls out of the urn until there are none left. What is the probability that the sixth ball picked will be blue? I tried to do this by case work, because in order for the sixth pick to be blue we can't have the first five picks use up all the blue marbles. So we can split it into three cases for the first five picks.  No blue ball was picked One blue ball was picked Two blue balls were picked Three blue balls were picked  I quickly realized that there is too much adding and calculating doing it like this. Since there are $5$ subcases for $2$, and $10$ subcases each for $3$ and $4$. Is there a better way to do this problem? Thank you!

We had this question arise in class today and I still don't understand the answer given. We were to assume that drawing cards are independent events. We were asked what the probability that the second card drawn is a queen if we take two from the deck. The answer given was 4/52, which seems counter-intuitive to me. How is the probability still 4/52 if there was a card drawn before it? What if the first card drawn was a queen?


When I boot up my laptop (which by the way boots really fast), everything is okay even when typing my password. Then, as soon as desktop shows, the typing (and only that it seems) gets really slow.  What I mean by "slow" is if I write for example "Hello world!" in notepad the characters will appear one by one with seconds between them. After a few minutes it eventually catches up and writes evrything (if the sentence was long enough of course), and then there's no more issue at all.  It's not only letters, for example for "windows+r" (execute) to run i need to have both keys pressed for a few seconds, until the windows shows up.  I bought the laptop with Windows 8 on it and eventually upgraded to windows 10. The problem appeared long after and has been around for a while, I'm just now trying to get rid of it.  I should mention, I'm using the integrated keyboard and only my mouse is plugged on.  Here it is on Asus' website   I have no idea how to diagnose or solve the issue whatsoever. Any help is welcomed :)

I have upgraded my computer using a core i5 2500K from Windows 7 x64 to WIndows 10 x64, and the whole system runs fast and reliable, with one exception: after booting from SSD, which takes only about 10 seconds, my keyboard is really slow for the first 1 or 2 minutes right after booting. "Slow" means that when I start notepad, and type some characters, it takes a second for each character to appear on screen. Everything else is fast, including mouse movement, starting programs, only keyboard input is that slow. After 1 to 2 minutes, the keyboard suddenly behaves normally again.  This happens with every kind of keyboard I connect, no matter if I use the legacy PS/2 adapter, or USB.  Does anybody have any idea what might be the cause of this strange behaviour?


Does your reputation get compromised when the flag is declined?  Do you get notified when your flag has been reviewed?

The  (click on your number of helpful flags in your profile) is cool, however some posts have a gray background, some don't. What does it mean?  example:


I would like to connect at least two USB-C monitors, but maybe 3 if possible. Firstly, should it work? Secondly, will it work well in terms of performance? I mostly need the monitors for text editing and web browsing (not video editing or gaming).

How do I find out the number, type, resolution & refresh rate of additional monitors I can attach to my MacBook or MacBook Pro?  This is an attempt at a canonical QA, as per the Meta QA -   to try prevent the myriad "same but different" questions we get on every possible combination of computers, cable & monitors There are perfectly good resources out there that Ask Different should not have to duplicate the efforts of.


As I understand, the metric system starts with an arbitrary weight, and calls it $1\, \mathrm{kg}$, then the volume of this weight in water gives the meter. And then the energy is defined based on the meter, second and kilogram.  My question is: given that the relation between meter, kg and joule relies on the density of water (or did so originally), how can we possibly tie them again with $E=mc^2$ by adding the speed of light? The density of water seems completely uncorrelated to the speed of light.  Intuitively I would have added an extra constant to Einstein's equation.

Why is it that many of the most important physical equations don't have ugly numbers (i.e., "arbitrary" irrational factors) to line up both sides?   Why can so many equations be expressed so neatly with small natural numbers while recycling a relatively small set of physical and mathematical constants?  For example, why is mass–energy equivalence describable by the equation $E = mc^2$ and not something like $E \approx 27.642 \times mc^2$?  Why is time dilation describable by something as neat as $t' = \sqrt{\frac{t}{1 - \frac{v^2}{c^2}}}$ and not something ugly like $t' \approx 672.097 \times 10^{-4} \times \sqrt{\frac{t}{1 - \frac{v^2}{c^2}}}$.  ... and so forth.    I'm not well educated on matters of physics and so I feel a bit sheepish asking this.   Likewise I'm not sure if this is a more philosophical question or one that permits a concrete answer ... or perhaps even the premise of the question itself is flawed ... so I would gratefully consider anything that sheds light on the nature of the question itself as an answer.    EDIT: I just wished to give a little more context as to where I was coming from with this question based on some of the responses:  @Jerry Schirmer comments:      You do have an ugly factor of $2.997458 \times 10^8 m/s$ in front of everything. You just hide the ugliness by calling this number c.   These are not the types of "ugly constants" I'm talking about in that this number is the speed of light. It is not just some constant needed to balance two side of an equation.  @Carl Witthoft answers:      It's all in how you define the units ...   Of course this is true, we could in theory hide all sorts of ugly constants by using different units on the right and the left. But as in the case of $E=mc^2$, I am talking about equations where the units on the left are consistent with the units on the right, irrespective of the units used. As I mentioned on a comment there:     $E=mc^2$  could be defined using units like $m$ in imperial stones ($\textsf{S}$), $c$ in cubits/fortnight ($\textsf{CF}^{−1}$) and $E$ in ... umm ... $\textsf{SC}^2\textsf{F}^{−2}$ ... so long as the units are in the same system, we still don't need a fudge factor.   When the units are consistent in this manner, there's no room for hiding fudge constants.


The question seems rather simple, yet it is suprisingly difficult.   There is a bug under one of six tiles and it is my job to find it. The tiles lie in a row. At night, the bug moves randomly 1 tile, so it either moves to the left or to the right. During the day you are allowed to pick up one tile to see if the bug is there. If you choose the tiles as optimal as possible, how many days will it take you to find the bug, at most?   The answer is multiple choice, namely a.) 6 days, b.) 8 days or c.) 10 days.   Lets defne the tiles as follows: the first tile on the left we call 1, then the tile on the right of the first tile we call 2, etc. until we have a set {1,2,3,4,5,6}.   MY APPROACH: [I was thinking that you start with 3. You find that it's not there, but the bug could have been under 4 and moved during the night under 3, so the next day you lift 3 again. It's not there, but the bug could have gone from 5 to 4 and now there is again a possibility that the bug moves under 3 when you decide to lift another tile, so again you would think it's best to lift 3. Since the bug can move between 5 and 6 back and forth it is useless to continue looking under just tile 3. But if you decide to look under another tile there is always the possibility that the bug will move under the tile you looked under one days before that. Therefore, it seems to me that the problem is unsolvable.   I tried to visualize the problem on a lattice of 10 by 6 where every day (the number of rows) is representated by a row of 6 tiles. Then drawing two lines from every tile in the first row to the left and right tile in the row below and leaving out the lines from the tile I looked under. Then I eliminated the tiles to which the most lines come to. But after 10 days there are about 4/5 lines per tile, so this doesn't work even though it seems rock solid to me.]  Does anybody have any suggestions or solutions?

There are five boxes in a row. There is robot in any one of these five boxes. Every morning I can open and check a box (one only). In the night, the robot moves to an adjacent box. It is compulsory that he moves. I need a method to ensure that I can catch the robot within ten days. How to do so?


I am working in QGIS 2.4. I have changed the CRS of all the layers and in the project properties to EPSG:102739 - NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet.   I am in print composer trying to create a scale bar and I can not figure out why the scale is so off. I am trying to go from feet to miles and it just creates a really long scale bar. Basically 1 mi = 5280 is what I am going for I have already checked each layer and they are all in state plane 4203. I am not sure what I am missing. I checked other threads about scale in QGIS and I am still at a loss. I have tried flipping the conversion around and its still not working.   Edit 2: Sounds crazy is there a difference between Qgis for Windows and for Linux. I loaded the exact same data(just copied and pasted the file with the map and data) to a windows computer. Opened it and everything works fine.   Edit: The answer given  does not address my issues. I have already done everything in that answer. All of my layers have been resaved with projection and the project projection has been changed.

The scale of my map is wrong, no matter what coordinate system I use in my project. The map and all objects show the correct coordinates but the scale of the map shows nonsense and the measurement tool gives wrong dimension.   The map should be like 1:10000 but qgis shows 1:1. Anyone an idea?


Say for instance my opponent uses  against my  ... can I use the counters on it to deal damage before it getting destroyed? Also can I use those counters to deal damage at anytime in any players turn?

I'm a relatively new player to Magic: the Gathering. I was reading  to try to understand exactly when it's okay to cast instants (e.g. ) and use some abilities (e.g.  should be tappable sometime during other peoples' turns), but I don't seem to be making much progress: as I come to understand some things, others make less sense.  My confusion is boundless  For instance: to cast  one needs priority. Spells go on the stack, and priority gets passed at some points (I have no idea when), and effects on the stack are resolved when both players have passed priority. But when is that? I can't find any mention of when the other player gets the priority to cast an instant, except on their own turn. Furthermore,  states that during the Main Phase:     505.4. Second, the active player gets priority. Players may cast spells and activate abilities. The active player may play a land.   So players (plural) may cast spells, but only the active player has priority, so only the active player can cast an instant. The turn rules, and the rules on , never mention any point at which the other player gets priority, so when can they possibly Cancel?  In addition, you can only cast a spell when the stack is empty, so the entire stack must be able to be resolved in your turn at some point.  I need an explanation!  I could go on a bit more. There is also  which can be overloaded to "Counter each spell you don't control", which seems like it could only possibly work with an understanding of the stack.  Could someone explain, in simple English:   When can Instants be cast? When can tap abilities be used? What do Instants and abilities have to do with the Stack and Priority?


Once in a while I get this bizarre behavior on my iPhone 5's screen with iOS 8.3.1. (The button says 'Approve' - in Hebrew).  I can't say if its SMS/MMS or something else. But it feels like Malware.   Anyone familiar with this behavior or something similar? What should I do next?

This weird message keeps appearing every few days and it's very irritating. It always contains spam messages that asks me to accept or cancel invitations to random services (weekly jokes, pics etc). From googling, I believe this is some sort of Flash SMS:    Can someone explain if this is caused by an app or forced through the service provider as I would like to know how to disable these permanently.


I want to draw plans for domestic buildings and be able to estimate materials and costings. Is there relatively simple CAD software available. I've searched extensively with no success.

Just that. By good I mean something at the level of SolidWorks, AutoCAD, or similar. This is a complete limitation for me (and many others) to use Ubuntu.


I'm currently learning linear algebra using textbook Linear Algebra Done Wrong, and I encountered this problem.  Let $X$ and $Y$ be subspaces of a vector space $V$. Show that $X\cup Y$ is a subspace if and only if $X\subset Y$ or $Y\subset X$  I don't really have any idea. I only figured out that 0 is in the set, so it is not empty. What else should I do? Thanks!!

I was doing some linear algebra exercies. One I did is this: Prove that the union of two subspaces $U,W$ of $V$ is a subspace of $V$ if and only if one contains the other.   My proof is this: If one is a subset of the other $U \subset W$ then the union is $W$ which by assumption is a subspace. If neither is contained in the other there exists an example where the union is not a subspace: let $V$ be the xy-plane, $U$ the x-axis and $W$ the y-axis. Then the union is not closed with respect to addition.   My question is whether it is valid to prove something by example? How would you prove this in another way?


I had QGIS version 2.18.14 installed on my ubuntu. Today I wanted to make an update, but some problems came up. So I deleted QGIS and wanted to reinstall it. But everytime I try to reinstall it, this comes up:  The following packages have unmet dependencies:  python-qgis : Depends: libqgis-analysis2.18.15 but it is not going to be installed                Depends: libqgis-server2.18.15 but it is not going to be installed                Recommends: liblwgeom-dev but it is not going to be installed  qgis : Depends: gdal-abi-2-2-2 but it is not installable         Depends: libqgis-analysis2.18.15 but it is not going to be installed         Depends: libqgis-app2.18.15 but it is not going to be installed         Recommends: qgis-plugin-globe but it is not going to be installed         Recommends: qgis-plugin-grass but it is not going to be installed         Recommends: qgis-provider-grass but it is not going to be installed E: Unable to correct problems, you have held broken packages.   How can I fix this problem?

I am aware that this could be a duplicate topic but I am struggling for a several days.  I upgraded QGIS from 2.8 to 2.18 and after that everything get broken. I couldn't use PostGIS extension on pgadmin3.  I figured out that there were a conflict with a libgdal1h: if installed, it removes other libraries used by PostGIS and vice versa.   I tried several tutorial about how to install QGIS, like for example:       I tried every suggestion reported on line, like for example:          Always, the reply of sudo apt-get install qgis python-qgis is:   The following packages have unmet dependencies:   python-qgis : Depends: python-qt4-sql but it is not installable                Depends: python-qgis-common (= 1:2.14.8+20trusty-ubuntugis) but it is not going to be installed                Depends: python-psycopg2 but it is not installable                Depends: python-qscintilla2 but it is not installable                Depends: python-jinja2 but it is not installable                Depends: python-markupsafe but it is not installable                Depends: python-pygments but it is not installable                Depends: python-yaml but it is not installable                Depends: python-pyspatialite but it is not installable                Depends: libqgispython2.14.8 but it is not going to be installed                Depends: libqgis-analysis2.14.8 but it is not going to be installed                Depends: libqgis-core2.14.8 but it is not going to be installed                Depends: libqgis-gui2.14.8 but it is not going to be installed                Depends: libqgis-networkanalysis2.14.8 but it is not going to be installed                Depends: libqgis-server2.14.8 but it is not going to be installed                Recommends: liblwgeom-dev but it is not installable  qgis : Depends: gdal-abi-2-1-0 but it is not installable         Depends: libgdal20 (>= 2.0.1) but it is not installable         Depends: libgeos-c1v5 (>= 3.4.2) but it is not installable         Depends: libqgis-analysis2.14.8 but it is not going to be installed         Depends: libqgis-app2.14.8 but it is not going to be installed         Depends: libqgis-core2.14.8 but it is not going to be installed         Depends: libqgis-gui2.14.8 but it is not going to be installed         Depends: libqgis-networkanalysis2.14.8 but it is not going to be installed         Depends: qgis-providers (= 1:2.14.8+20trusty-ubuntugis) but it is not going to be installed         Depends: qgis-common (= 1:2.14.8+20trusty-ubuntugis) but it is not going to be installed         Recommends: qgis-plugin-globe but it is not going to be installed         Recommends: qgis-plugin-grass but it is not going to be installed         Recommends: qgis-provider-grass but it is not going to be installed E: Unable to correct problems, you have held broken packages.   I have removed all the packages and the libraries so I do not have any library related to postgis, postgres and QGIS with the Synaptic Package Manager and all with the commands:  sudo apt-get purge qgis sudo apt-get autoremove qgis sudo apt-get --purge remove qgis sudo apt-get update   But the problem is not solved yet.  I tried to remove the repo of ubuntugis and/or debian on the file /etc/apt/sources.list.  Nothing.   And I do not understand why, using this source  I still have issues about the dipendences.   What should I do?   I am planning to format my laptop hoping this will help me with broken packages.. for the broken packages, I have already tried:  sudo apt-get update –fix-missing sudo apt-get install -f   but nothing fixed.


my server yesterday started sending thousands of spam emails. I blocked it adding default_transport=No transport to the postfix main.cf. But now of course I can't send legit emails as well.  I have 10+ websites in my Centos Server, using Nginx. I went via FTP to see if there were new strange files or recently edited (checking the dates). I couldn't find anything suspicious.   I want to track the source of the script sending emails - they are being sent using the generic email address configured in the server.  In my php.ini I added:  mail.log = /var/log/phpmail.log   And I created the file phpmail.log via touch on /var/log/ and I restarted the server using the command systemctl restart php-fpm  The file phpmail.log is not populating, still 0KB. Now it has the following righs:  -rwxrwxrwx  1 apache apache       0 Aug 10 12:47 phpmail.log   But I tried to give him nginx.nginx, root, root, web.web, but nothing seems to work. (of course after each chmod change I restarted once again php-fpm, and tried to send emails using for example the mail() contact form on my website).  And I tried also to make this file populate before adding default_transport=No transport to main.cf.  Not sure if it's useful for you, but mailq is full of mails in the queue.  Do you have any idea what is wrong with the file phpmail.log and why it's not populating, and/or how to find the root cause that is preventing it to populate?

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


I´m a beginner in Java or Programming in general, and i´m trying to make a program that works as a calculator to things like Sigma notation, Pythagoras theorem...  But as a "noob" i am at programming, i need help.  Well, i have a menu to choose the kind of "calculator" you want, and i have some JButtons. How can i make so that when one of those buttons is clicked, change what is showing in the frame. Like if button1 is clicked, in the frame it would appear a different menu? i don´t know if i made myself clear, but i hope you could help me.

To put it simple, there's a simple java swing app that consists of JFrame with some components in it. One of the components is a JPanel that is meant to be replaced by another JPanel on user action.  So, what's the correct way of doing such a thing? I've tried  panel = new CustomJPanelWithComponentsOnIt(); parentFrameJPanelBelongsTo.pack();   but this won't work. What would you suggest?


Suppose that $f(z)$ is holomorphic, such that $e^{f(z)} $ is a constant. I want to show that $f(z)$ also has to be a constant. I have solved the problem by assuming that $h(z) = e^{f(z)} $ also is holomorphic. How can i prove that $ h(z) $ is holomorphic?

If $g(w)$ and $f(z)$ are holomorphic functions, show that $g(f(z))$ is also holomorphic.   From the assumptions we have that for some $A,B$,  $$\lim_{h\rightarrow 0}\frac{g(f(z)+h)-g(f(z))}{h}=A,$$  $$\lim_{h\rightarrow 0}\frac{f(z+h)-f(z)}{h}=B.$$  We want to prove that there exists $C$ with  $$\lim_{h\rightarrow 0}\frac{g(f(z+h))-g(f(z))}{h}=C.$$  The second equation means, by definition of the limit, that for any $\varepsilon > 0$, there exists $\delta$ such that $0<|h|<\delta$ implies $$\left|\frac{f(z+h)-f(z)}{h}-B\right|<\varepsilon.$$  I don't know how to get to $\dfrac{g(f(z+h))-g(f(z))}{h}$ from here.


Sorry to cross-post this between here , but this is very strange and seems to be something larger than what SuperUser mods usually handle.  I honestly don’t know  to even link to it, but what the heck is this about?


I have a shell script that has multiple variables , I would like to export a specific variable from the script to a command I want to run after the shell script is executed #!/bin/sh  a=10 b=20 c=a+b echo $a export a  and the command I want to run is echo $a

I have multiple Amazon EC2 accounts and want to quickly be able to switch variables, such as $EC2_HOME, using a script.  I have have a shell script set up like this:  #!/bin/sh export EC2_HOME=/home/me/.ec2 echo $EC2_HOME   When I run the script I know that EC2_HOME is set, but I thought that using export would make the variable stick around after the script completed. It does not, as running echo $EC_HOME does not show anything.  I know this must be very rudimentary Linux scripting knowledge, but I don't know it. I tried looking for related questions without luck - so my apologies if this is a duplicate.


Prove by induction: $\sum_{i=1}^n i^3 = \left[\sum_{i=1}^n i\right]^2$. Hint: Use $k(k+1)^2 = 2(k+1)\sum i$.  Basis: $n = 1$ $\sum_{i=1}^1 i^3 = \left[\sum_{i=1}^1 i\right]^2 \to 1^3 = 1^2 \to 1 = 1$.  Hypothesis: Assume true for all $n \le k$.  So far I have the following:  $$\sum_{i=1}^{k+1} i^3 = (k+1)^3 + \sum_{i=1}^k i^3$$  $$(k+1)^3 + \left[\sum_{i=1}^k i\right]^2$$

How can I prove that     $$1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$$    for all $n \in \mathbb{N}$? I am looking for a proof using mathematical induction.  Thanks


I am using local Ubuntu server with Apache 2.4. I am running as a default user Ubuntu and each time I need to change something under /var/www/ I have to use sudo to avoid permission denied messages.   I have thought an alternative to create a directory under my home, say public_html which will contain all documents and then create a symlink under /var/www/ which points to public_html  Is it safe to point Apache to my home directory? Can you guys recommend any other idea to avoid repeated use of sudo?

This is a  about File Permissions on a Linux web server.   I have a Linux web server running Apache2 that hosts several websites. Each website has its own folder in /var/www/.  /var/www/contoso.com/ /var/www/contoso.net/ /var/www/fabrikam.com/   The base directory /var/www/ is owned by root:root. Apache is running as www-data:www-data. The Fabrikam website is maintained by two developers, Alice and Bob. Both Contoso websites are maintained by one developer, Eve. All websites allow users to upload images. If a website is compromised, the impact should be as limited as possible.  I want to know the best way to set up permissions so that Apache can serve the content, the website is secure from attacks, and the developers can still make changes. One of the websites is structured like this:  /var/www/fabrikam.com     /cache     /modules     /styles     /uploads     /index.php   How should the permissions be set on these directories and files? I read somewhere that you should never use 777 permissions on a website, but I don't understand what problems that could cause. During busy periods, the website automatically caches some pages and stores the results in the cache folder. All of the content submitted by website visitors is saved to the uploads folder.


I want to see my best league position of all times. Is that possible? Do we have a history for the league positions? Because I was in top 0.30% of something but I don't remember what. Now I am in top 3% of the week, but I want to check all my league achievements. I don't have a lot for now, but in the future I hope it will be useful to check my history for such a thing. That didn't solve my question. As I still can't find in which league I was in the top 0.30%  Marked as duplicate? I think the people that voted for the should be banned, because they are kidding with their priviledges. I think when they see the word league and they mark as duplicate. To these who marked it as duplicate: people please read better these questions, because we the users are wasting time to think think think, then write and its well formed question, its unique question and you are ruining the website and OP passion for writing.   A feature where we can see our top rankings in each league would be great!

Not sure if this is a duplicate question, How do I find out my all time best ranking? Since ranking move up and down, Is there a way to find out my all time best rank? In case we do not have it, I suggest we take this as a request proposal and provide this feature for the users.


Is which town or region does the Handsmaid's Tale take place?

This is a somewhat peculiar question, and I recognize that it may end up being closed.  However, it concerns something that has been puzzling me for some years about Margaret Atwood's The Handmaid's Tale.  (Atwood's well-known feelings about SF notwithstanding, this novel is clearly science fiction.)  Early in the book, there is the first description of The Wall:     The Wall is hundreds of years old too; or over a hundred, at least. Like the sidewalks, it's red brick, and must once have been plain but handsome. Now the gates have sentries and there are ugly new floodlights mounted on metal posts above it, and barbed wire along the bottom and broken glass set in concrete along the top.   Aside from the sidewalks being made of the same brick as the wall, there seems to be very little that marks this wall as specifically identifiable.  And yet, from the first time I read this passage, I knew this wall.  Having lived in Cambridge, Massachusetts, I could tell that this was the wall of Harvard Yard, which I walked beside some many times over the years.  Reading on in the novel, it quite clear that I was quite correct in my identification of the wall.  What I a wondering is whether this was a particularly lucky flash of insight on my part, or whether there was something in the text that pointed to Harvard Square as the location of the book.  Is there something, early in The Handmaid's Tale, that points specifically to its geographic setting?


I'm having some trouble resetting my Windows 10 PC. Whenever I start the reset process, it always shows up an error message, saying "there was a problem resetting your PC".  Can anyone suggest as to what could be the source of the problem and how to overcome it.

I'm having some strange kind of trouble with Windows 10. Whenever I try to install any application, a pop-up dialogue box is supposed to come, asking for our confirmation, but such a box doesn't appear, and as a result, I'm unable to install any application.  Whenever I run an installation, the screen dims, but the dialogue box doesn't appear. The sound of the dialogue box does appear though. Can anyone help me with this kind of problem. What could be the reason for this and what are the possible solutions for the same.


I have oppoortunities related to opportunities via a lookup, and a wanted to find all the opportunities with children opportunities.  When I did it, I got the error - that inner and outer selects should not be the same object type.  Here is the offending query:   Select id, name, stagename, (Select Id, name, stagename From Opportunities__r where stagename = 'Pre-Renewal' and type = 'Renewal')  from opportunity  where id in (select Parent_Opportunity__c from Opportunity)

I'm trying to return parent opportunities that only have 1 or more related child opportunities, but I can't get my query right.   List <opportunity> oppsWithPotentialChildrenToBeUpdated = [Select id, name, stagename, (Select Id, name, stagename From Opportunities__r where stagename = 'Pre-Renewal' and type = 'Renewal')                                                                                From Opportunity o where id in  (Select opportunityId from Opportunities__r where stagename = 'Pre-Renewal' and type = 'Renewal') ];   Error:   Compile error at line 1 column 59  sObject type 'Opportunities__r' is not supported. If you are attempting to use a custom object, be sure to append the '__c' after the entity name. Please reference your WSDL or the describe call for the appropriate names.   I checked the schema in eclipse, and Opportunities ought to work.... I tried Opportunities__r, Opportunities__c, and Opportunity


I want to change my Ubuntu architecture from x32 to x64 thus wanted to boot from a live disk. Pressing F2 takes me to a screen giving Ubuntu Advanced Options and memtest

I have a dual boot laptop (Windows 10). I ran general updates and now my Ubuntu won't boot.   I ran in recovery mode and still it freezes in the same place.      Kernel panic – not syncing: Attempted to kill init! exit code=0x00007f00


The following is the code for the matrix I want to put in one column in a two column format in IEEEtran.cls. Any alternative solutions are welcome.  \begin{equation}    \begin{bmatrix}        V_A \\         V_B \\        V_C \\        V_{A^t} \\        V_{B^t} \\        V_{C^t} \\        V_P \\        V_Q \\        V_R \\      \end{bmatrix}        = \begin{bmatrix}                     L_{AA} & M_{AB} & M_{AC} & M{AA^t} & M_{AB^t} & M_{AC^t} & M_{AP} & M_{AQ} & M_{AR} \\                    M_{BA} & L_{BB} & M_{BC} & M_{BA^t} & M_{BB^t} & M_{BC^t} & M_{BP} & M_{BQ} & M_{BR} \\                    M_{CA} & L_{C} & M_{CC} & M_{CA^t} & M_{CB^t} & M_{CC^t} & M_{CP} & M_{CQ} & M_{CR} \\                    M_{A^tA} & L_{A^tB} & M_{A^tC} & M_{A^tA^t} & M_{A^tB^t} & M_{A^tC^t} & M_{A^tP} & M_{A^tQ} & M_{A^tR} \\                    M_{B^tA} & L_{B^tB} & M_{B^tC} & M_{B^tA^t} & M_{B^tB^t} & M_{B^tC^t} & M_{B^tP} & M_{B^tQ} & M_{B^tR} \\                    M_{C^tA} & L_{C^tB} & M_{C^tC} & M_{C^tA^t} & M_{C^tB^t} & M_{C^tC^t} & M_{C^tP} & M_{C^tQ} & M_{C^tR} \\                    M_{PA} & M_{PB} & M_{PC} & M{PA^t} & M_{PB^t} & M_{PC^t} & M_{PP} & M_{PQ} & M_{PR} \\                     M_{QA} & M_{QB} & M_{QC} & M{QA^t} & M_{QB^t} & M_{QC^t} & M_{QP} & M_{QQ} & M_{QR} \\                     M_{RA} & M_{RB} & M_{RC} & M{RA^t} & M_{RB^t} & M_{RC^t} & M_{RP} & M_{RQ} & M_{RR} \\                      \end{bmatrix}  \frac{\mathrm d}{\mathrm d t}   \begin{bmatrix}        I_A \\         I_B \\        I_C \\        I_{A^t} \\        I_{B^t} \\        I_{C^t} \\        I_P \\        I_Q \\        I_R \\      \end{bmatrix}     \end{equation}

I have a group of equations, such as  /begin{gather} Eq1 // Eq2 // Eq3 // Eq4 /end{gather}   Unfortunately, some of the equations in the group are too long to fit on the page.  For equations that are only slightly too long, is there a way to slightly decrease the font size of that equation only?  For equations that are much too long, is there any automated way to split the equation (where the computer decides where and how to split it to fit the page width), or would this split need to be defined by the user?  Thank you, Kevin  P.S.  Here is my code where the matrix is too wide and goes off the end of the page:  \documentclass{article} \begin{document} \[ \mathbf{L} = \left[ \begin{array}{*{6}{c}} {{L_S}}&{ - {L_{SS}}}&{ - {L_{SS}}}&{M\cos \theta }&{M\cos \left( {\theta  +       \frac{{2\pi }}{3}} \right)}&{M\cos \left( {\theta  - \frac{{2\pi }}{3}}   \right)}\\ { - {L_{SS}}}&{{L_S}}&{ - {L_{SS}}}&{M\cos \left( {\theta  - \frac{{2\pi }}{3}} \right)}&{M\cos \theta }&{M\cos \left( {\theta  + \frac{{2\pi }}{3}} \right)}\\ { - {L_{SS}}}&{ - {L_{SS}}}&{{L_S}}&{M\cos \left( {\theta  + \frac{{2\pi }}{3}} \right)}&{M\cos \left( {\theta  - \frac{{2\pi }}{3}} \right)}&{M\cos \theta }\\ {M\cos \theta }&{M\cos \left( {\theta  - \frac{{2\pi }}{3}} \right)}&{M\cos \left( {\theta  + \frac{{2\pi }}{3}} \right)}&{{L_R}}&{ - {L_{RR}}}&{ - {L_{RR}}}\\ {M\cos \left( {{\theta} + \frac{{2\pi }}{3}} \right)}&{M\cos \theta }&{M\cos \left( {\theta  - \frac{{2\pi }}{3}} \right)}&{ - {L_{RR}}}&{{L_R}}&{ -     {L_{RR}}}\\ {M\cos \left( {{\theta _2} - \frac{{2\pi }}{3}} \right)}&{M\cos \left( {{\theta _2} + \frac{{2\pi }}{3}} \right)}&{M\cos \theta }&{ - {L_{RR}}}&{ - {L_{RR}}}&{{L_R}} \end{array}\right] \] \end{document}


while I have no errors in the Text, I get a few warnings, from which most are similar: LaTeX Warning: You have requested package 'moderncvheadii', but the package provides 'moderncvheadii'. To me this warning seems rather weird...  Here a short section:  \documentclass[12pt,a4paper]{moderncv} \usepackage[latin1]{inputenc} \usepackage[T1]{fontenc} \usepackage[ngerman]{babel} \usepackage[scale=0.8]{geometry} \usepackage{graphicx} \moderncvtheme[blue]{casual}    The rest of the script is simple and repetitive (section, subsection, cvline).  PS: I use TeXnicCenter if that might be useful.

I know what this message means in general ("do not add path names in package names"), and my question is not a duplicate of , where the two names differ (by the path name). In my case the package names are really identical (without path name in both cases)!  I'm working on MiKTeX 2.9, with latest updates (I refreshed FNDB). I get this with the latest moderncv package (version 2.0), MWE:  \documentclass{moderncv} \moderncvtheme{classic} \name{Foo}{Bar} \begin{document} \end{document}   where I get  You have requested package `moderncvheadi', but the package provides `moderncvheadi'. You have requested package `moderncvbodyi', but the package provides `moderncvbodyi'.   What does trigger this warning in this case and how can I solve it? Is it a bug in moderncv? The official source on  looks fine to me.


I'm always curious about why we have to use "is" or "does" when we mention "more than one thing" though this phrase means few people, not one person. Please let me know if you don't mind, and sorry for gramatically incorrect sentences cuz I'm not a native.

However, if no x satisfies the equation or more than one x does—that   is the solution is not unique—the problem is said not to be well   posed.   In the line(source: ) above it uses "more than one does", but logically and intuitively it should be "more than one do" since "more than one" means two or more, then it is plural. I have tried my best to interpret it as it is, but hardly can I convince myself to make "more than" collocate with "does" as an adv., which may only make it make sense.


I'm wondering what is difference between these both?     She has been banned   and     She is banned

In a technical environment, what is the most suitable sentence to use when answering to someone about a problem that they had and we solved it for them:   The problem is solved The problem has been solved


Mathematic formulars in titles are not displayed correctly in the Android App. Always I see the "raw" code behind it.  If I switch to view in browser e.g. using Chrome, it works again.  One example is this    I am using version 1.0.89 on a Samsung Galaxy S5 mini with Android 5.1.1  Is this known?

See this screenshot:         MathJax is now enabled for the Android app (yay!). However, it doesn't work in titles.  Could this be fixified?


When I define a class with variables already assign, instantiate it and use __dict__ to get variables as a dictionary, I get an empty list.  In [5]:  class A(object):     a = 1     b = 2     text = "hello world"      def __init__(self):         pass      def test(self):         pass  x = A() x.__dict__  Out[5]: {}   But when I declare variables in __init__ and use __dict__ it returns variables which were assigned after instantiation of class.  In [9]:  class A(object):     a = 1     def __init__(self):         pass      def test(self):         self.b = 2         self.text = "hello world"   x = A() x.test() x.__dict__  Out[9]: {'b': 2, 'text': 'hello world'}   Why is that __dict__ returning only variables declared after instantiation of class  Edit Answer:  When an instance is created like x = A()  x.__dict__ stores all the instance attributes.   A.__dict__ stores the class attributes

Is there any meaningful distinction between:  class A(object):     foo = 5   # some default value   vs.  class B(object):     def __init__(self, foo=5):         self.foo = foo   If you're creating a lot of instances, is there any difference in performance or space requirements for the two styles? When you read the code, do you consider the meaning of the two styles to be significantly different?


Trying to center some text in a div that cover the whole page. Any horizontal adjustments that I make are fine yet vertical adjustments either do not work or push the text below the center of the page.     .home{  max-width:100%;  height:100%;  text-align:center;  background:url(desktop_1.jpg) no-repeat center center;    -webkit-background-size: cover;    -moz-background-size: cover;    background-size: cover; } .home .text{  height:100%;  width:100%; }  .home .text h1{  vertical-align:middle; }

 MOSTACK

 Lorem ipsum dolor sit amet
     ENTER SITE

     Understand that this may seem as a dupliacte yet tried solutions on other posts and none are working  EDIT- SOLVED used the following css    .home{  width:100%;  height:100%;  text-align:center;  background:url(desktop_1.jpg) no-repeat center center;    -webkit-background-size: cover;    -moz-background-size: cover;    background-size: cover; } .home .text{  max-width:100%;  height:50%;  position: absolute;     margin: auto;     top: 0;     left: 0;     right: 0;     bottom: 0; }  .home .text h1{  font-family:'Raleway', sans-serif;  padding-top:30px;  padding-bottom:100px;  font-size:60px;  color:black;  max-width:100%;  height:40%;  position: absolute;     margin: auto;     top: 0;     left: 0;     right: 0;     bottom: 0; }  .home .text a{  text-decoration:none;  padding-top:100px;  font-size:20px;  color:black;  max-width:100%;  height:0%;  position: absolute;     margin: auto;     top: 0;     left: 0;     right: 0;     bottom: 0; }

 MOSTACK
     ENTER SITE

I want to center a div vertically with CSS. I don't want tables or JavaScript, but only pure CSS. I found some solutions, but all of them are missing Internet Explorer 6 support.
Div to be aligned vertically
   How can I center a div vertically in all major browsers, including Internet Explorer 6?


Let $f:[0,\infty)\to\mathbb{R}$ differentiable and suppose that $$\lim_{x\to\infty}f'(x)=L.$$ How can I prove that $$\lim_{x\to\infty}\frac{f(x)}{x} = L\;?$$  I have solved some similar problems using the Mean Value Theorem, and I am trying to use it again in this one, but nothing works. For example, I tried to apply the MVT in $[x, 2x]$ but it does not work. Some hint?

If $f$ is differentiable on $(a,\infty)$, Show that if $f'(x)\rightarrow L$ as $ x \rightarrow \infty$, $-\infty \leq L \leq \infty $  then  $ f(x)/x \rightarrow L $ as $x \rightarrow \infty$.   Deduce further that if $f(x) \rightarrow M$ as $ x\rightarrow \infty$ , and $ f'(x)\rightarrow L $ as $ x \rightarrow\infty $ then $ L = 0$   For the first part I tried converting $f(x)$ to $F(\frac{1}{x})$ and $x \rightarrow 0$ and then using L'Hospital's rule but I am getting stuck. How do I proceed with this problem ?


when we want install device driver there are diferent device driver for each version of windows. e.g:debice driver for windows xp x86 is different from windows 7 x86 and windowd 8 x86 Why need Different device driver for each version of windows? why cant have same driver for all version or only have 2 for x86 and x64?? i want explain it in more technical detail

I am running into a problem with drivers on different versions of Windows. Why are newer versions not backward compatible (to a certain extent)? What changes between verions of windows in the OS that requires different drivers?


equivalence relation on a set breaks it into disjoint sets. does 'disjointness' make sense in classes. specifically, given a category, isomorphism classes of objects makes sense or not. can it be so that initially we start with a class of objects,but equivalence classes form a set.

Can someone please explain to me how to deal with equivalence relations on classes instead of sets? Is there some sort of generalisation of relations?  Thank you


If $a$ and $b$ are co prime and $n$ is a prime, show that:  $\frac{a^n+b^n}{a+b}$ and $a+b$ have no common factor unless $a+b$ is a multiple of $n$  Also enlighten me why $n$ has to be prime so that $\frac{a^n+b^n}{a+b}$ and $a+b$ have no common factor unless $a$+$b$ is a multiple of $n$?

Let $p$ be prime number ($p\gt2$) and $a,b\in\mathbb Z$ ,$a+b\neq0$ ,$\gcd(a,b)=1$ how to  prove that $$\gcd\left(a+b,\frac{a^p+b^p}{a+b}\right)=1~~\text{or}~~ p$$  Thanks in advance .


I am trying to get the response time of a server so for example I am using below curl command I got of the internet  curl -w "@curl-format.txt" -o /dev/null -s http://wordpress.$   The curl-format.txt looks like the following:  n         time_namelookup:  %{time_namelookup}n            time_connect:  %{time_connect}n         time_appconnect:  %{time_appconnect}n        time_pretransfer:  %{time_pretransfer}n           time_redirect:  %{time_redirect}n      time_starttransfer:  %{time_starttransfer}n                         ----------n              time_total:  %{time_total}n n   This command works fine when called through the command line.   However when I try to use it in crontab and output the times to a file called Restime.text it does not work.  Below is the crontab command I am using.  * * * * * /usr/bin/curl -w "@curl-format.txt" -o /dev/null -s http://wordpress.$ >> /home/ubuntu/newApp/Restime.txt    Any advice as to where I am going wrong ?  Kind Regards.

This is a  about using cron & crontab.   You have been directed here because the community is fairly sure that the answer to your question can be found below. If your question is not answered below then the answers will help you gather information that will help the community help you. This information should be edited into your original question.  The answer for 'Why is my crontab not working, and how can I troubleshoot it?' can be seen below.  This addresses the cron system with the crontab highlighted.


This might be an odd question. To my knowledge one have to initialize a language babel in Latex. But I was wondering if it's possible to make a variable inside overleaf indicating the languages and then some sort of if statement, such that certain files are included if variable var equals Language A another set of files is included if variable var equals languages B and so forth. Instead of having 20+ different documents, then have them all in the same document and switch between languages?

He is my issue: I need to keep many documents (CV, research statement, research projects, list of abstracts, etc.) updated and ready to be sent for applications, sometimes in quite a rush. However, depending on the place I send them to, the language change, and I keep translating again and again in one way or the other. I want to avoid it, and to stop juggling between many basically copies of the same content. Is there a way to define a "mode" (say "English" or "German" or "French"), to write in a single file the content in both languages, e.g. \english{2020-2023: PhD student} \german{2020-2023: Doktorand} \french{2020-2023: Étudiant doctoral}  and to define at the top of the document the mode, e.g. \mode{english}  so that the printed pdf will consider only the required language entries (here, English)? Basically, I will of course need to keep doing the translations and writing them, but it will be much more convenient to do for each bit of content that needs to be updated rather than rechecking the whole document to see if it is indeed the last version every time. I would like it to be robust enough to e.g. keep working with beamers, moderncv, or any class or environment already existing.


What is the meaning of the term "format", as used in  I received to  I posted on this forum:     LaTeX3' isn't released as a format: perhaps you mean expl3?    I received to the above mentioned question also mentions this term:     You can dump a format from the current expl3 but it will just do nothing because it doesn't provide basic things like an output routine. If you are already running some format (Plain TeX, LaTeX2e, ConTeXt, lollipop, etc) you can input the expl3 macro package and use everything it provides.            I think you are asking whether there exists a format which has expl3 preloaded, to which the answer is no.

I know LaTeX and I've heard that LaTeX is a set of macros in TeX. But what does it exactly mean?


I would like to evaluate: $$\displaystyle\int_0^1 \frac{\log(1+x)}{1+x^2}\, dx$$  I have tried to evaluate this using integration by parts but failed. How can I evaluate it?


In case of password security I often read, that the use of rainbow tables is appreciated. It is possible, that I don't get it right, but my current perspective is just confusion.  You save a couple of salts in a table, but you must reference them in the table with password hash, which allows you to rebuild the password hash. So I would do it like this:  By creating a new password, save hash ( input + salt ) into the table  Table: Password: hash, Salt reference: 123  I thought, this is used to prevent "dictionary attacks", but what happens, when the user uses a password, which is contained by the dictionary. The attacker can easily pass through.  Just a list with events, which are happening in my point of view:   User/Attacker "types" in this login data Email/Username is looked up and returns salt reference Look up salt with reference Build password Check password in table with email/username   So how can the salt matter, if it is automatically looked up? This might be a bit confusing, but in the end it makes all sense to me.

I'm having some trouble understanding the purpose of a salt to a password.  It's my understanding that the primary use is to hamper a rainbow table attack.  However, the methods I've seen to implement this don't seem to really make the problem harder.  I've seen many tutorials suggesting that the salt be used as the following:  $hash =  md5($salt.$password)   The reasoning being that the hash now maps not to the original password, but a combination of the password and the salt.  But say $salt=foo and $password=bar and $hash=3858f62230ac3c915f300c664312c63f.  Now somebody with a rainbow table could reverse the hash and come up with the input "foobar".  They could then try all combinations of passwords (f, fo, foo, ... oobar, obar, bar, ar, ar).  It might take a few more milliseconds to get the password, but not much else.  The other use I've seen is on my linux system.  In the /etc/shadow the hashed passwords are actually stored with the salt.  For example, a salt of "foo" and password of "bar" would hash to this: $1$foo$te5SBM.7C25fFDu6bIRbX1.  If a hacker somehow were able to get his hands on this file, I don't see what purpose the salt serves, since the reverse hash of te5SBM.7C25fFDu6bIRbX is known to contain "foo".  Thanks for any light anybody can shed on this.  EDIT:  Thanks for the help.  To summarize what I understand, the salt makes the hashed password more complex, thus making it much less likely to exist in a precomputed rainbow table.  What I misunderstood before was that I was assuming a rainbow table existed for ALL hashes.


In the relation between displacement and pressure wave in sound how can there be maximum pressure when there is zero displacement of a particle,doesn't the exact opposite happen in a compression wave when the particles are at the maximum displacement and pressure is the highest?

My teacher told  me that pressure variation is maximum at mean position in a sound wave. Though by proof of pressure wave and displacement wave, I am convinced but in understanding the physical meaning I am facing a problem as I have a counter argument. According to me pressure variation should be maximum there at extreme position because  pressure is maximum due to the fact that density is maximum as all particles come closest to each other due to compression.Hence by this argument the claim that pressure variation is maximum at mean position contradicts my understanding. please help


how to prove that expression is a tautology by using law of logic?? Thank you in instant

I am looking for a way to prove that the statement, $[(p \to q) \land (q \to r)] \to (p \to r)$, is a tautology without the help of the truth table. By using only Laws and Theorems like De Morgan's Law, Domination Law, etc. Also, I can't use the rules of inference. Please help, thank you.


I want to put a circle/dot ::before an element  &#8226  •  nothing I am doing is visible!  .line ::before{     content:'&#8226';     }   and  .line ::before{     content:'•';     }   (I see nothing)  I can't get this to work even with just text  I know content only accepts text, but I still don't see anything if I do:  .line ::before{     content:'xxx';     }   How do I get css ::before to show up?  (note: the css rule is in the default style sheet on page load so it should be applying to any new element ...)  How do I display this dot in ::before?

How do you use the CSS content property to add HTML entities?  Using something like this just prints &nbsp; to the screen instead of the non-breaking space:  .breadcrumbs a:before {     content: '&nbsp;'; }


I'm new to ubuntu, and I'm just now installing it, i've backed up some files and I'm going to completely system restore and I'm saving some files onto .rar's. from my website database.  I was wondering if I can use .rar on ubuntu?

I just realized I can't unrar .rar files on my Ubuntu machine!  What's the easiest way to accomplish this fundamental task? If possible I'd love something like 7Zip that I can just right Click, and extract and have the program worry about how to do it regardless if it's a .zip, a .rar or a .foo compressed file.


I am only curious, how the general lock on deleted posts interacts with the diamond.

Moderators should be able to comment on things after normal users are unable to, such as when a post is deleted or locked. As a moderator on Programmers, I try to leave a comment (if necessary) before taking the appropriate action on the post. However, in the time it takes to write a comment (which often includes digging up links to the most relevant resources and citing specific problems), things may happen - users can leave new answers or comments, Community or the author can delete the post, and so on.  A responding moderator should be able to take the appropriate moderator action on the post to remove the problematic behavior/content from the site and then leave a comment so that the user can learn why this behavior is unacceptable or what needs to be done to fix the content (if it's fixable).  This would effectively change the workflow from {hope no one will do anything -> write a comment -> hope nothing happened to the post that invalidates or blocks the comment -> moderate} to {moderate -> comment}.  Diamond moderators should be able to comment on posts that are otherwise locked from comments.  When a moderator comments on a deleted post, the comment should generate an inbox notification for the post's author just as it would if it were posted right before the post was deleted.


I have a domain, flyh2.com.  I use a CNAME to forward www.flyh2.com to flyh2.elasticbeanstalk.com where my web site is hosted. This is the only way Amazon allows custom domain names. A records aren't allowed.  I'd like people to simply type  (without the www) and still have visitors see my web site.  Originally I used CNAME to forward both the naked and the www records to my web site, but it seemed to cause problems.  Incoming mail was being returned to sender:  Fwd: Returned mail: see transcript for details <mark@flyh2.com>... Deferred: Connection timed out with flyh2.elasticbeanstalk.com. Message could not be delivered for 6 hours Message will be deleted from queue   Seems that the CNAME on the naked domain was overriding the MX records.  Now I've changed the CNAME on the flyh2.com record to point to www.flyh2.com and in turn www.flyh2.com to CNAME to flyh2.elasticbeanstalk.com.  My MX records are set up correctly, but the CNAME on the naked domain seems to override them. Do I have to use an A record?

This is a  about CNAMEs at the apices (or roots) of zones   It's relatively common knowledge that CNAME records at the apex of a domain are a taboo practice.  Example: example.com. IN CNAME ithurts.example.net.  In a best case scenario nameserver software might refuse to load the configuration, and in the worst case it might accept this configuration and invalidate the configuration for example.com.  Recently I had a webhosting company pass instructions to a business unit that we needed to CNAME the apex of our domain to a new record. Knowing that this would be a suicide config when fed to BIND, I advised them that we would not be able to comply and that this was bunk advice in general. The webhosting company took the stance that it is not outright forbidden by standard defining RFCs and that their software supports it. If we could not CNAME the apex, their advice was to have no apex record at all and they would not provide a redirecting webserver. ...What?  Most of us know that  insists that A CNAME record is not allowed to coexist with any other data., but let's be honest with ourselves here, that RFC is only Informational. The closest I know to verbiage that forbids the practice is from :     If a CNAME RR is present at a node, no other data should be   present; this ensures that the data for a canonical name and its aliases   cannot be different.   Unfortunately I've been in the industry long enough to know that "should not" is not the same as "must not", and that's enough rope for most software designers to hang themselves with. Knowing that anything short of a concise link to a slam dunk would be a waste of my time, I ended up letting the company get away with a scolding for recommending configurations that could break commonly used software without proper disclosure.  This brings us to the Q&A. For once I'd like us to get really technical about the insanity of apex CNAMEs, and not skirt around the issue like we usually do when someone posts on the subject.  is off limits, as are any other Informational RFC applicable here that I didn't think of. Let's shut this baby down.


The idea is simple:   Load a text file into a string. Split this string into paragraphs. Split all paragraphs into words. Add each individual word to an ArrayList.   The result is an ArrayList containing all of the words in the text file.   The procedure works; it loads all of the words in an ArrayList fine.  HOWEVER, any "IF" statements to find a specific item in the ArrayList do not work.  EXCEPT: if the word is a newline.  public String loadText(String resourceName){       // Load the contents of a text file into a string     String text = "";     InputStream stream = FileIO.class.getResourceAsStream(resourceName);     BufferedReader reader = new BufferedReader(new InputStreamReader(stream));     String str = "";     try {         while ((str = reader.readLine())!=null){             text += str + "\n";         }     } catch (Exception e) {         System.out.println("Unable to load text stream!");     }     return text; }  public void test(){      ArrayList<String> collectionOfWords = new ArrayList<String>();     String text = loadText("/assets/text/intro.txt");      // Split into paragraphs     String paragraphs[] = text.split("\n");     for (String paragraph: paragraphs){          // Split into words         String words[] = paragraph.split(" ");          // Add each word to the collection         for (String word: words){             collectionOfWords.add(word);         }          // Add a new line to separate the paragraphs         collectionOfWords.add("\n");     }      // Test the procedure using a manual iterator     for (int i=0; i<collectionOfWords.size(); i++){           // ===== WHY DOES THIS WORK?         if (collectionOfWords.get(i)=="\n")             System.out.println("Found it!");          // ===== BUT THIS DOESN'T WORK???         if (collectionOfWords.get(i)=="test")                 System.out.println("Found it!");          // NOTE: Same problem if a I use:         // for (String word: collectionOfWords){         //   if (word=="test")         //     System.out.println("Found it!");     } }   Sample of text file: The Quick Brown\n Fox Jumps Over\n test the lazy dog\n  Any ideas?  I am at the point to just scratch my design and try something totally different...

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


i came across  and i saw the given solution but i can not understand how it proves the given problem. Ok i get that $lcm(5,7)= 35$ and it is the same as the $(mod 35)$. Please can someone help me?

How do i prove that $17^n−12^n−24^n+19^n≡0(\mod35)$ for every possitive integer n. Can anyone give me a hint of how to start?


Is there a general rule for the determinant of the sum if we know the determinants? For example:  If $\rm \det A = 1$ and $\rm\det B = 2$ and there is $ \rm A+B$, is $\rm\det (A+B) = \det (A) + \det (B) = 3$ ? Thank you.

Well considering two $n \times n$ matrices does the following hold true: $$\det(A+B) = \det(A) + \det(B)$$ Can there be said anything about $\det(A+B)$?  If $A/B$ are symmetric (or maybe even of the form $\lambda I$) - can then things be said?


Tried to use this KDEConnect on Linux Mint yesterday. No joy. This morning I installed Ubuntu thinking it may have more luck. But no connection. What I've tried:  Turned off 5ghz band on router cuz phone & linux box was on different bands. tried manually connecting to Ubuntu from phone by inputting ip address. tried GSConnect, still no connection used gufw to allow KDE Connect to pass through  I'm using a BT Home Hub 2. None of this has worked. I'm getting the feeling that KDEConnect is perhaps no longer functional, is this true? Or is there a step I'm missing. Much appreciate any help anyone can offer, I'm only using Linux a few months so any help should be dumbed down.

How to install and run the Gnome extension  to connect your Android device with Ubuntu and integrate the device with Gnome Shell, Nautilus, Nemo file browser and Firefox (or Chrome) to be able to transfer files from/to phone, send SMS/text, get notification, monitor battery, sync clipboard between phone & desktop, control volume & music playback and more?


The c# static constructors is guaranteed to execute only once. Therefore, if I have say ten threads accessing a member of class A, and the static constructor of A hasn't been run, and the static constructor of A takes 10 seconds to run, these threads will block for ten seconds.   This seems amazing to me - how is this achieved within the JIT/CLR? Does every access to a static field enter a lock, check if the static constructor is initalized, then initialize it if it isn't? Wouldn't this be very slow?    To be clear, I want to know how an implementation of the specification achieves this. I know that static constructors are threadsafe, this question is not asking that. It is asking how the implementation ensures this, and whether it uses locks and checks under the hood (these locks are not locks in c sharp, rather locks used by the JIT/CLR/other implementation).

In other words, is this Singleton implementation thread safe:  public class Singleton {     private static Singleton instance;      private Singleton() { }      static Singleton()     {         instance = new Singleton();     }      public static Singleton Instance     {         get { return instance; }     } }


I want to check the existence of the date, I have int variables ( representing format ) - day( dd ), month ( MM ) and year ( YY ). Here's my code:      SimpleDateFormat df = new SimpleDateFormat("YYMMdd");     df.setLenient(false);      try {         Date d = df.parse(""+day+month+year);     } ...   Because variables are in int I have problem when day for example can be 01 ( 1 digit in int ), or 21 ( 2 digits in int ) and I'm getting error as I have 'dd' in my format. Is there an easy way how I can use my numbers to check the validity of the date?

How do you left pad an int with zeros when converting to a String in java?  I'm basically looking to pad out integers up to 9999 with leading zeros (e.g. 1 = 0001).


I am trying to define a wrapper for my own listings:  \newenvironment{mycode} { \begin{lstlisting}[language=C] } { \end{lstlisting} }   So I can use it:  \begin{mycode} void main(); \end{mycode}   When compiling, I get this:     *** (job aborted, no legal \end found)     The full code is here:  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{listings}  \newenvironment{mycode} { \begin{lstlisting}[language=C] } { \end{lstlisting} }  \title{example} \author{andry.tino } \date{September 2019}  \begin{document} \maketitle \section{Introduction} Hello  \begin{mycode} void \end{mycode}  \end{document}

I am trying to define an enviroment for a specific programming language, F#. Here's my code:  \definecolor{bluekeywords}{rgb}{0.13,0.13,1} \definecolor{greencomments}{rgb}{0,0.5,0} \definecolor{turqusnumbers}{rgb}{0.17,0.57,0.69} \definecolor{redstrings}{rgb}{0.5,0,0}  \lstdefinelanguage{FSharp}     {morekeywords={let, new, match, with, rec, open, module, namespace, type, of, member, and, for, in, do, begin, end, fun, function, try, mutable, if, then, else},     keywordstyle=\color{bluekeywords},     sensitive=false,     morecomment=[l][\color{greencomments}]{///},     morecomment=[l][\color{greencomments}]{//},     morecomment=[s][\color{greencomments}]{{(*}{*)}},     morestring=[b]",     stringstyle=\color{redstrings}     }  \newenvironment{fslisting}   {     \lstset{         language=FSharp,         basicstyle=\ttfamily,         breaklines=true,         columns=fullflexible}     \begin{lstlisting}   }   {     \end{lstlisting}   }   Then I'm trying to use it as such:  \begin{fslisting} type 'a Process = 'a Signal IObservable \end{fslisting}   But it doesn't work. The output log says that the listing is not terminated - or is terminated by the document. So the rest of the document is also formatted as a listing, which is of course not the intention.  What am I doing wrong here?


I just know that I'm going to look like a crackpot, but here goes. The number $\pi$ is defined as the ratio of the circumference of a circle to its diameter. So there is an assumption here that all circles are similar. Using undergraduate calculus (Moise), I can analytically convince myself that this is true. But how would a 5th century geometer prove this synthetically?

Is there a proof that the ratio of a circle's diameter and the circumference is the same for all circles, that doesn't involve some kind of limiting process, e.g. a direct geometrical proof?


Is it possible to make the top of my model glossy, and have the glossiness fade into matte toward the bottom of the model? (Or any combination of surface variations, this is just an example) Thank you!

I am trying to render an object that has opaque base and gradually becomes clear/translucent at the top in Blender cycles.  Please see the attached image (which was not made with blender).


Changed Title and Meta description in Yoast seo for some pages, but it was not showing in the website even after google crawls the website. Instead it was showing the same old title that we put in the head section for all pages of the website.Only that same tile is showing for all the pages

Before we launched our website, we had set up a "coming soon" page and google picked up the title and description from its contents. So the description in the search results said:     Coming soon! Visit example.org for updates.   It's been a few weeks since we launched our website. We've even created a sitemap and submitted it to Google. In Google Search Console, the pages have been crawled and all the pages are appearing as expected on Google, EXCEPT the homepage which is still not updated! The title and description of the homepage in google search results still says "coming soon.".***  I checked on bing too, but it appears to be fine there.  All other pages seem to be indexed fine on Google. I don't even have any crawl errors in my reports. So what seems to be the problem? I've already waited for 2 weeks.


Are you allowed to develop closed source, commercial plugins for QGIS? License is GNU GPL, which is normally very restrictive.  Update: Assume it is a python plugin (possibly open-sourced), that call's a closed-source dll, which doesn't link to anything from QGIS.

I would like to create a plugin using commercial software.  Does the QGis licence permit this?  Are there any restrictions on the licence I can choose to apply to my plugin?