I wanted to understand how to use Excel better, and I had some question regarding it. Which exchange site is good for this?

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


I want to show that no two of the spaces $(0,1), \ (0, 1], \ [0,1]$ are homeomorphic, with the hint: what happens if you remove a point from each one of these spaces.  No idea where to begin, except that it concludes a chapter on connectedness.  All these spaces are all in the subspace topology of the usual topology on $\mathbb{R}$.  Edit  (Thanks @Chris Culter)  So far what I've got is: Let $A = (0,1] - \{1\}$.  If $f:(0,1] \rightarrow (0,1)$ is a homeomorphism, then $f$ restricted to $A$ is a homeorphism onto a subset of $(0,1)$ with one and only one point removed.  But any removal of a point in $(0,1)$ results in a disconnected space, while at the same time $f_A$ ensures that the space is connected, it being a continuous image of a connected space $A$.  Therefore there is no continuous bijective map between the two spaces let alone a homeomorphism.  A similar agument shows that $[0,1]$ and $(0,1)$ are not homeomorphic.    I can't seem to show that $(0,1]$ and $[0,1]$ are not homeomorphic using this method though.

As the topic is there exist a homeomorphism between either pair of $(0, 1),(0,1],[0,1]$


Lets assume we have a dependent varible which can take on three values: 1, 2 and 3.   Is there any differences in running multiple binary logit regressions(ie. 1 vs 2 and 2 vs 3) or the multinomial logit regressions with 2 as the base group? Will the results be the same as the base group is the same in both cases? I've tried to look it up but can't seem to find an answer.  Thanks in advantage, have a nice weekend.  Regards, Martin

Lets say we have a dependent variable $Y$ with few categories and set of independent variables.    What are the advantages of multinomial logistic regression over set of binary logistic regressions (i.e. )? By set of binary logistic regression I mean that for each category $y_{i} \in Y$ we build separate binary logistic regression model with target=1 when $Y=y_{i}$ and 0 otherwise.


Let's say the two ends A and B of a wormhole are moving relative to one another.  If I stick a starship halfway into end A of the wormhole, does the part of the starship that sticks out of end B move along with end B, or does it remain stationary with respect to end A?  Assuming it does move, will a force be exerted on it if end B of the wormhole for some reason suddenly accelerates or decelerates?

First, I consider the following as given: All the galaxies, solar systems and planets in the universe travel on a different route at a different velocity through space, mostly moving away from each other.  Now, imagine we would be able to create a wormhole from planet x in solar system y in galaxy z to planet a in solar system b in galaxy c. Since both planets are moving in different directions, I see 2 options how it could work.  1) The wormholes would travel with the planets, constantly changing the spacetime-wrapping.  2) The wormholes would stay at the position they were initially created, which means the planets would move away from them, after they were created. But the spacetime-wrapping would stay the same.  I know most people (me included) think that option 1 is the case. But the following question really made me think, and led me to the question I'm now asking:  If option 1 was the case, what would happen if someone entered the wormhole? Would he keep the velocity of the planet where he entered at the planet he came out, which means he would move away from the target planet? Or would he adopt the velocity of the target-planet? If the latter was the case, would this person notice the slow-down/speed-up/direction-change? Could the person even die?  I'm not a physicist, so I may assume totally wrong concepts. I'm sorry about that.


I bought my new laptop yesterday it's a HP pavilion 17 177-sb i believe and it has a UEFI BIOS so I usually install ubuntu the day I buy laptops and I did that this time too. I can only boot and shutdown the OS a few times before it crashes at the gnome logo saying it stopped all the services and then the screen goes black and the windows 8 HP logo appears and it just boots Win8 perfectly fine but ubuntu won't boot I currently have Secure boot turned on(doesn't really matter because it doesn't get fixed when I turn it of) and legacy support disabled! Only a reinstall helps and it just keeps screwing it up  if someone can help me with this I would appreciate it!  thanks,  noahvt

I have a Sony VAIO S series with Windows 8 preinstalled, and I installed Ubuntu 12.10 on a new partition. When the PC boots Grub is display, and I can choose between Windows 8 (didn't worked at the beginning, had to change Grub settings) and Ubuntu 12.10. When I select Ubuntu 12.10 everything is OK, but when I use Windows 8, and I restart Grub isn't displayed anymore (Windows 8 boots immediately).  I booted a Ubuntu 12.10 LiveUSB, used efibootmgr, and found out that Windows 8 (each time it boots) changes EFI default bootloader from Grub to Windows Boot Manager.  How do I change this in Windows 8? I read something about bcdedit, but it does not work or I don't know how to use it...


I installed Ubuntu 13.04 alongside the existing Windows 7 OS. The Ubuntu installation completed successfully, and it asked me to restart my computer. When I restarted, it was just Windows 7 that loaded as usual, but Ubuntu wasn't there. Can anyone tell me what's wrong?

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


Last time, I question that the sumatrapdf cannot show the time. you can see   And I get the answer it doesn't support the java.  Then I use the Adbreader,it's ok.  Now, Regardless of things whether Javascript or not, I only want to know  whether I can have another choice to add the time in beamer except the tdclock. Say thank you in advance  :)

I find some errors when using \usepackage[timeinterval=1]{tdclock}while opening the SumatraPDF.  As  zeniko says     The tdclock package only works in PDF readers supporting JavaScript,   which SumatraPDF currently doesn't and likely never will.   so I want to find the package like tdclock which can be used in SumatraPDF  Ps: tdclock is used in beamer to show the clock.


I'm trying to create a sort of html select dropdown using the bootstrap dropdown. In the list I'm hiding the default selected value but on change I delete the chosen option from the list and add the default value to make it selectable again etc. like this:  Selected: Cool  Option: Code  Option: Bro   When selecting Code it becomes:  Selected: Code Option: Bro Option: Cool  Now this works well when an option has not been selected before but when an option already has been selected you cant select it again.. Anyone who knows what I'm doing wrong here?    var from = $('#selected_from').data("curfromcoin"); var to = $('#selected_to').data("curtocoin");  $('#from_coin a').on("click", function() {   $('#selected_from').html($(this).data('fromcoin'));   $('#selected_from').data('curfromcoin', $(this).data('fromcoin'));   $("#from_drop").append($("
" + from + "
"));   $("#from_drop li").remove(":contains('" + $(this).data('fromcoin') + "')");   from = $('#selected_from').data("curfromcoin"); });
   <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">    Cool   </button>

Code

Bro

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


Could the requirement of a dark matter for the missing mass in the universe simply be explained by objects having high relativistic mass change with respect to other objects?  If this is not the case, how is it explained mathematically?

In a question  Ron Maimon comments that "relativistic mass makes gravity, not rest mass."  If so, does that mean that the faster that stars orbit the galaxy the larger the relativistic mass of the galaxy therefore more gravity therefore the stars orbit even faster therefore the gravity gets even more therefore the stars keep on getting faster ...  So the speed of stars and mass of galaxy would be correlated with age and history of the galaxy or galaxy clusters and that's why calculations of galaxies' masses don't add up.


There are two ways that spells are rolled for in D&D 5e, depending on the spell: attack rolls rolled by the players and saving throws rolled by the DM.  But as far as I can see, saving throws could be made as attack rolls instead. I know D&D 4e did it this way, with players making attacks against AC/Fortitude/Reflex/Will Defenses instead of the DM making Fort/Ref/Will saving throws and players making attack rolls against AC.  I don't really see why the designers of D&D 5e would choose to have two different ways to roll something that, as far as I can tell, could be simplified into one mechanic (and ), so I wondered if I'm missing something important that distinguishes the two methods.  I guess it boils down to: Is there any difference in probabilities or practical concerns between one or the other method, or are they interchangeable?  This is related to  and  This question is focused on if there is any practical difference, regardless of why they actually made that design decision.

In D&D 4E as with many RPGs, characters have a fixed armour value or AC. When attacking, the attacker must roll a die to overcome the target's AC. In 4E offensive magic works the same way: the target has a fixed Fortitude/Reflex/Will defence determined by their stats, and in order to hit, the attacker rolls to overcome whichever defence is relevant.   However it was not always like this. Some spells in 3E and now again in 5E work the opposite way. In those editions the target is the one who rolls against a fixed value determined by the caster's stats, in order to avoid spell-damage.  Both methods compare the attacker and target's stats, and have an element of randomness. I personally like the 4E system as it simplifies combat without leaving anything out. Why was the decision made, when designing the early D&D editions (and still when iterating upwards into (A)D&D 1e–3e), to use saving throws to control spells?  Answers should consist of designer quotes and not personal opinions.


I am looking for a way to make biblatex to display the author names in format of First Middle Initial Last. I want biblatex to automatically convert from other formats of author names to the desired display format.  A MWE is like this:  \documentclass[]{article} \usepackage{filecontents}  \begin{filecontents*}{bib.bib}  @article{jdoe,     author={Doe, John Paul},     journal={Journal},     title={Title},     year=2014,     pages={111--222}, } \end{filecontents*}  \begin{document} \noindent Citation: \cite{jdoe}. \printbibliography[] \end{document}   I want to know how to add biblatex macros to make the display of the author names to be as John P. Doe, no matter what the format of the author names in .bib are specified. Is there an easy way to do so?  I have tried to use \DeclareNameFormat{first-last} in the preamble, but this did not work for me. Could you please help? Thanks.

The first given name of an author or editor in my bibliography should be written out, but all further first names should be abbreviated (initials with a period -- and space if there are multiple first names/initials, see below). I am using style=authoryear with BibLaTeX (v. 2.7) and Biber (v. 1.7).  My bibliography looks like this:     Doe, John Arthur Kyle (2013). The secret life of John Doe.   It should look like this:     Doe, John A. K. (2013). The secret life of John Doe.   Minimal example:  example.tex  \documentclass{scrartcl}  \usepackage[ngerman]{babel} \usepackage[babel,german=quotes]{csquotes} \usepackage[backend=biber,style=authoryear]{biblatex} \bibliography{bibliography}  \begin{document}  \cite[123]{Doe} \printbibliography  \end{document}   bibliography.bib  @book{Doe,     title = {The secret life of John Doe},     author = {Doe, John Arthur Kyle},     year = {2013} }   (Worked with said versions of BibLaTeX and Biber, Texmaker (v. 4.0.3) and MiKTeX (v. 2.9.4813).)  I could not find a solution in biblatex.def and firstinits=true abbreviates all first names, including the first one.


I try to make a tagged Armor Stand look at the same place as the player, but I can't find a way to do it.  For example, if the player looks in the direction of the (x, y, y) block, the Armor Stand should look at the (x, y, z) block.   For now I wrote the following command, but it only rotates the Armor Stand in the same direction as the player, it doesn't make it look at the same place:  /execute as @e[tag=my_armor_stand] at @s rotated as @p run teleport @s ~ ~ ~ ~ ~  If this should take more than one command, it is also okay.

I want to execute a command if I am looking at a specific block. A command should only be executed if it is targeted.


I have html code like that:

   I am developing function findvalue in C#:  if (line.Contains("title")) {     sTitle = findvalue("title", line); }   findvalue function is simple string opreations function which work like that for this line  find function will retrun News Letter value, similarly I will get value of other attributes like href, src atc

I'm looking for a library/method to parse an html file with more html specific features than generic xml parsing libraries.


Examples:   .bashrc .config/fish/config.fish   I would like to know which is more common and what pros and cons they each have. I imagine a dotfile would be easier to change, since it is right in the home directory, but it seems .config would be easier to carry around, since it is one directory with everything in it.  Do applications usually support just one, or both?  Would it be a good idea to pick one, then symlink for each application? For example, if I wanted a dotfile, I could use ln .config/fish/config.fish .fish and just edit .fish, right?

I've noticed that some applications put their configuration files to ~/.config/appname while others use ~/.appname (the classic way, AFAIK) for this. What's the sense in this distinction and what could be better to consider for an application of mine?  UPDATE: Looks like my (XUbuntu 11.10 default) $XDG_CONFIG_HOME is set to ~/ and the most of the applications in my system (like Mozilla Firefox, Adobe Flash Player, Midnight Commander, Opera, Wine, etc.) comply to this. But there are still many applications (like Compiz, Deadbeef, VLC, Qt Creator, Google Chrome, XFCE, etc.) using ~/.config/ instead. Another suspicious thing is that directories in ~/.config/ are not themselves hidden (no dot in their names) - aren't application config dirs expected to have constant own names without depending on the location ($XDG_CONFIG_HOME value)?


Please find the image i am tying like this but it is not coming where i am doing wrong.?    .skills ul {   width: 100%;   margin: 10px 0px 0px 0px;   padding: 0px;   float: left; }  .skills li {     border: 1px solid #F0F0F0;     list-style: none;     text-decoration: none;     text-transform: capitalize;     padding: 7px 10px 0px 10px;     background: #F0F0F0;     color: #414141;     font-size: 13px;     text-align: left;     float: left;     border-radius: 50px;     margin: 3px 6px;     height: 31px;     position: relative; }  .skills li a {     position: absolute;     top: -8px;     right: 8px;     background: #FF6158;     width: 15px;     height: 15px;     border-radius: 50%;     display: flex;     align-items: center;     justify-content: center;     text-decoration: none;     color: #fff; } .skills li img {  vertical-align: middle; height: 38px; width:38px; border-radius:50%;  }

  AJAX                     <input type="checkbox" name="skills" value="3" style="display:none">                     x

  Action Script 3.0 (Mac Version)                     <input type="checkbox" name="skills" value="6" style="display:none">                     x

Why won't vertical-align: middle work?  And yet, vertical-align: top does work.   span{   vertical-align: middle; }
      Doesn't work.


I cooked chicken and made up enchilada with sour cream and the green sauce and made extra. How many days can I keep them in the refrigerator before reheating?

How do I know if a given food or ingredient I have is still good, or if I should discard it?  How can I best preserve a food or ingredient?     This broad question is intended as a "general reference" question to quickly answer many how long will food keep for? questions. Please feel free to edit this question to expand and clarify as needed.


The sentence is :"One of the most important things in his life WAS/WERE his speeches".  I'm not sure about the concordance! Could you help me please?

My fish's native habitat is rice fields. My fish's native habitat are rice fields.   Which one is correct? I'm pretty sure it's the first, since 'is' modifies 'habitat,' but it still sounds weird...


I would like to use some tool from command line, to check and download mail, from different providers (gmail, hotmail, yahoo...) periodically and automatically, and save them as text files, preferably a text file for each email. I don't want my previous emails, so it shoud be possible to specify not to download previous emails, but only new ones since this solution is set up. I have been looking for such a thing and found fetchmail, but it saves all the messages in a single mbox file. What do you suggest? Thanks  EDIT: This is not a duplicate of the question suggested, since I am not going to send any email from this computer. It will not even have a keyboard or mouse connected. My question is about downloading all my emails individually as plain text file ("readable"), and stored in txt format.


How can I customize Ubuntu installation ? I don't want install Libre office or other app. I need something like Ubuntu server but without server tools .

I would like to customize Ubuntu live CD by installing some additional packages. I have followed   but it doesn't seems to work. Can anyone provide clear instructions?   Note: I do not prefer Remastersys, manual way will be appreciated.  Customization  Packages that I want to install:   Thunderbird    Samba    SSH       Changes that I need:   Remove Games menu from the Application menu Firefox shortcut on Desktop Radiance as the default Theme Different default Ubuntu Wallpaper   Configuration file changes   I want the panel to be placed at the bottom I want to paste my Samba configuration file instead of default Samba configuration I have few Firefox shortcuts and folders I would like to show that in Desktop Also it will be nice if you say me how to change the icon sets   Recent Updates   I have customized Ubuntu 10.10 with Firefox shortcuts and few folders on desktops. Everything went smooth. But the installer gets crashes after choosing the timezone. How do i fix this issue? Also setting wallpaper affects the login screen. The wallpaper which i set is displayed on the login screen also. I just want the default one for the login screen.


I'm trying to simulate a logistic regression. My goal is showing that if Y=1 is rare, than the intercept is biased. In my R script I define the logistic regression model through the latent variable's approach (see for example pp. 140 ):  x   <- rnorm(10000)  b0h <- numeric(1000) b1h <- numeric(1000)  for(i in 1:1000){   eps <- rlogis(10000)   eta <- 1+2*x+eps   y   <-numeric(10000)   y   <- ifelse (eta>0,1,0)    m      <- glm(y~x,family=binomial)   b0h[i] <- coef(m)[1]   b1h[i] <- coef(m)[2] }  mean(b0h) mean(b1h) hist(b0h) hist(b1h)   The problem here is that I don't know how to force the observations y to be balanced before (50:50), then unbalanced (90:10). As we can see with the function table(), in my script the proportion of ones is random.  table(y)   How to solve this problem?

I know I'm missing something in my understanding of logistic regression, and would really appreciate any help.  As far as I understand it, the logistic regression assumes that the probability of a '1' outcome given the inputs, is a linear combination of the inputs, passed through an inverse-logistic function. This is exemplified in the following R code:  #create data: x1 = rnorm(1000)           # some continuous variables  x2 = rnorm(1000) z = 1 + 2*x1 + 3*x2        # linear combination with a bias pr = 1/(1+exp(-z))         # pass through an inv-logit function y = pr > 0.5               # take as '1' if probability > 0.5  #now feed it to glm: df = data.frame(y=y,x1=x1,x2=x2) glm =glm( y~x1+x2,data=df,family="binomial")   and I get the following error message:      Warning messages:   1: glm.fit: algorithm did not converge    2: glm.fit: fitted probabilities numerically 0 or 1 occurred    I've worked with R for some time now; enough to know that probably I'm the one to blame.. what is happening here?


I am using the programming language  which does not have any built-in function for drawing samples from a multivariate Gaussian distribution. So I wonder, how can one implement a function that does the sampling for a multivariate Gaussian distribution? Note that I do have access to a function which can draw samples from a single-variable Gaussian distribution. Can I somehow use that function to draw samples for the multivariate case given a desired covariance matrix?  Also, if I'm not mistaken, I remember I read somewhere that one can draw samples from a single-variable Gaussian distribution as follow:  $\text{sample } = \mu + \sigma^2 \epsilon$  where $\mu$ is a mean, $\sigma^2$ is a variance and $\epsilon \sim U(0,1)$. Therefore, a generalization of the above equation for a multivariate Gaussian distribution is to have mean and [diagonal] covariance matrix. However, if not sure if this equation is valid by itself and whether it gives valid samples for a non-diagonal covariance matrix.   So I wonder, can you guys give me some insights on how one should go about generating samples for a multivariate Gaussian distribution given a desired non0diagonal covariance matrix and without having having access to a built-in function in a programming language? Also, I would appreciate your help to verify/prove the equation I wrote above.

I am currently trying to simulate values of a $N$-dimensional random variable $X$ that has a multivariate normal distribution with mean vector $\mu = (\mu_1,...,\mu_N)^T$ and covariance matrix $S$.  I am hoping to use a procedure similar to the inverse CDF method, meaning that I want to first generate a $N$-dimensional uniform random variable $U$ and then plug that into the inverse CDF of this distribution, so to generate value $X$.  I am having issues because the procedure is not well documented and there are slight differences between the  and a .  In my case, I am also choosing the parameters of the distribution randomly. In particular, I generate each of the means, $\mu_i$, from a uniform distribution $U(20,40)$. I then build the covariance matrix $S$ using the following procedure:   Create a lower triangular matrix $L$ where $L(i,i) = 1$ for $i=1..N$ and $L(i,j)  = U(-1,1)$ for  $i < j$ Let $S = LL^T$ where $L^T$ denotes the transpose of $L$.   This procedure allows me to ensure that $S$ is symmetric and positive definite. It also provides a lower triangular matrix $L$ so that $S = LL^T$, which I believe is required to generate values from the distribution.  Using the guidelines on Wikipedia, I should be able to generate values of $X$ using a $N$-dimensional uniform as follows:   $X = \mu + L * \Phi^{-1}(U)$   According to the MATLAB function however, this is typically done as:   $X = \mu + L^T * \Phi^{-1}(U)$   Where $\Phi^{-1}$ is the inverse CDF of a $N$-dimensional, separable, normal distribution, and the only difference between both methods is simply whether to use $L$ or $L^T$.  Is MATLAB or Wikipedia the way to go? Or are both wrong?


I have an old HP Mini 110-1026NR netbook. I recently installed Ubuntu 14.04 LTS 32bit. I am unable to connect to wifi and I do not have an ethernet cable, but I do have a working mac and a flash drive. The netbook has a Broadcom chipset BCM4312 and its PCI-ID is [14e4:4315]. The current kernel in use is b43-pci-bridge. Please help.

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


I wonder why isn't it implemented in the GUI? I know git has a content approach vs. single file approach but sometimes single file reverting is crucial.  For instance an .png graphics file from a few commits before is needed.  Probably I need to do a checkout but I'm still not sure as the concepts sometimes escape me.

I have made some changes to a file which has been committed a few times as part of a group of files, but now want to reset/revert the changes on it back to a previous version.   I have done a git log along with a git diff to find the revision I need, but just have no idea how to get the file back to its former state in the past.


Please refund to our customer. (This is talking about the receiver of the action, in this case the customer.) Please refund for our customer. (This is talking about the reason of the action)   I am not sure I understand it right. Can the second sentence also be used to indicate the receiver of the action?

The place is important for/to me.   I changed the variable for/to the project.   I can do to/for you.   In/for/to this project, I created a new method.      Does it mean any difference?  This bothered me many times.  Wish someone can answer.


I'm having a perplexing issue. If I try to run a script via:  root@myServer:~/dig# ./minerd.sh   I get:  -bash: ./minerd.sh: No such file or directory   If I try:  root@myServer:~/dig# ~/dig/minerd.sh   I still get:  -bash: /root/dig/minerd.sh: No such file or directory   If I do:  root@myServer:~/dig# ls ~/dig/minerd.sh   Then I get:  /root/dig/minerd.sh   So, the file is clearly there. I have also previously done chmod +x on it. But still, its not allowing me to run it for some reason. What am I doing wrong?  Edit: Even moving the file to a different name doesn't work:  root@myServer:~/dig# mv minerd.sh test.sh root@myServer:~/dig# ./test.sh -bash: ./test.sh: No such file or directory

I have currently a strange problem on debian (wheezy/amd64).  I have created a chroot to install a server (i can't give any more detail about it, sorry). Let's call its path /chr_path/. To make things easy, I have initialized this chroot with a debootstrap (also wheezy/amd64).  All seemed to work well inside the chroot but when I started the installer script of my server I got : zsh: Not found /some_path/perl (the installer includes a perl binary for some reasons)  Naturally, I checked the /some_path/ location and I found the "perl" binary. file in chroot environment returns :  /some_path/perl ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.2.5, not stripped   The file exists, seems ok, has correct rights. I can use file, ls, vim on it but as soon as I try to execute it - ./perl for example - I get : zsh: Not found ./perl.  This situation is quite understandable for me. Moreover :   I can execute other basic binaries (/bin/ls,...) in the chroot without getting errors I have the same problems for other binaries that came with the project When I try to execute the binary from the main root (/chr_path/some_path/perl), it works. I have tried to put one of the binaries with a copy of my ls. I checked that the access rights were the same but this didn't change anything (one was working, and the other wasn't)


I do this in my code:  Directory.Delete(MapPath("..\\Directory1"),true);   Now I got this error: System.IO.IOException: The directory is not empty.    What do I wrong anyone a idea?

I'm using .NET 3.5, trying to recursively delete a directory using:  Directory.Delete(myPath, true);   My understanding is that this should throw if files are in use or there is a permissions problem, but otherwise it should delete the directory and all of its contents.  However, I occasionally get this:  System.IO.IOException: The directory is not empty.     at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)     at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive)     at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive)     ...   I'm not surprised that the method sometimes throws, but I'm surprised to get this particular message when recursive is true.  (I know the directory is not empty.)  Is there a reason I'd see this instead of AccessViolationException?


I am Using Ubuntu Server and would like to know if it's possible to automatically restart services that go unresponsive. I am operating a standard LAMP stack and occasionally vital services need to be restarted but I want to do it in a programmatic way.

On Windows, you can set what should happen if/when a service fails.  Is there a standard way of achieving the same thing on Linux (CentOS in particular)?  A bigger part of my question is: how do you handle sockets that have been left open - for example in TIME_WAIT, FIN_WAIT1, etc states.  At the moment if the service I am developing crashes, I have to wait for the sockets to clear or change the listen port before I can then manually restart it.  Thanks for your help.


Could anyone explain how I write units properly in LaTeX? In the form kg.s^-1. They come out all slanted and squished together when i use math mode and \frac.

I know there are a few packages related to typesetting units:   unitsdef units, which can be seen as a "base package" used by unitsdef SIunits siunitx, which is the successor to SIunits maybe others? like cjwunits and hepunits   What is the difference between them? Do they also work inside Math mode? And, more importantly, which one should I use?  Suggestion for people trying to answer this question: show some examples of how to typeset both simple and complex units. For instance, try typesetting these items:   100 Celsius 3 x 10^5 km/s gravitational constant is measured in N m^2/kg^2 10 kHz = 1 s^{-4} sin(x) meters   I think these examples cover most needs when writing scientific texts: simple measurements (value + simple unit), values written in scientific notation, simple fractional units, complex fractional and squared units, units without any value accompanying them, units with arbitrary exponents, and arbitrary math code instead of a simple value.


all.  I'm designing an online form builder (think Forms in Google Docs / Spreadsheets).  The functionality is complete, but I'm not happy with the sorting capabilities.  Everyone that I have done usability tests with (five or so, including myself) didn't realize that the items could be sorted. This leaves me with a question:  Is there a best practice / most intuitive way to present a list to be manually sorted? As a few examples: Google Docs / Spreadsheets / Forms: Google's method is to have almost no indication that the items in their Forms can be sorted.  They use cursor: move; in their CSS to indicate that it is moveable, but nothing more. jQuery UI:  is fairly similar.  Almost no interface, save for a double arrow on the left hand side.  This is what I am currently using which is not being recognized by users. Up/down buttons: I can't think of any examples, but I have seen sorting using [+] and [-] buttons.  This seemed to be easy for users to pick up on, but meant the possibility of requiring n-1 clicks to get from the bottom to the top.

I have a table on a web page where I need to let the user reorder the rows. I was thinking of letting the user drag the rows to reorder them. But how would I let the user know that he could do that? Should I make an empty cell as the first column with dots or vertical lines like gmail has for each email in the inbox? Where can I get an image like that? Do I use a "grabbing hand" icon for the cursor or a "move" cursor? Do I show the cursor while hovering over the table or just the "grab area"? Do I let the user grab any part of the row to drag?


Ubuntu is not booting from a USB on my Acer V3-571G.  I have tried using a 8GB Sandisk Cruzer memory stick, formatted as FAT32, and this returned a black screen with the 'Syslinux: Peter Anvin et al' error. I used Unetbootin to create the memory stick.   This error always used to happen on my little Acer D250 netbook, and the reason was because the memory stick needed to be formatted as FAT, and not FAT32.  I formatted the memory stick as FAT and made another USB in Unetbootin. This time i was using my 4GB TDK USB drive. The Unetbootin menu came up but it froze when i clicked any of the boot options. Even if i left it past the boot timeout, it would still freeze.  I then used Lili USB creator instead, again with the TDK memory stick, but this doesn't work either. I get to the purple Ubuntu screen with the keyboard symbol and the man symbol, and then it goes onto a black screen with a blinking cursor.  The laptop is in Legacy boot mode with secure boot disabled.  Any help would be greatly appreciated. Thanks.

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


The default mount point for my external HD changed when upgrading from 13.04 to 13.10. Now the username is added as an extra level before the hd label.   So it used to be   /media/nameofhd   and now it became   /media/username/nameofhd   This breaks a lot of links I have set up to this disk.  I know that I can mount it manually and even automatically through /etc/fstab. What I want to know is why this behaviour changed and how I can change it back to the original?  blkid and fdisk don't show anything suspicious.  thx!

I recently upgraded from Mint 12 to Ubuntu 12.10 + Cinnamon.  I have an external usb drive that when I plug it in, automatically mounts to /media/[username]/Backup/.  Thing is, under Mint, it didn't include the [username] portion.  It just mounted to /media/Backup.  My question is, how do I switch back to that format?  I don't need the drive mounted under my username.  Just under media.  Thanks in advance.


I ran the meat through mincer once, formed burger approx. 3cm high, seasoned it, oiled from one side and put it in very heated pot and I put the lid on it. When I was turning it the other side down, it started to fall apart.  What do I need to change in my process to keep the hamburger whole? I guess the flaw can be that the meat is not enough oily, it didn't taste very oily. But the meat that I have isn't oily, will adding some external oil fix it?

Sometimes when cooking a burger I have had it completely fall apart for no apparent reason. Is this due to using a ground meat that is too lean? I don't add anything to the meat and don't spend too much time working the meat in forming the patty.


Is there a pair of words in English, where one is a grammatical negation of the other, but they are synonyms? For the negation I'm thinking about a negative prefix or suffix, like de-, dis- or -less, but it can also be built in other way. For example for the word 'likely' the hypothetical pair would be 'likely' and 'unlikely' and they would mean exactly the same (i.e. 'likely'). This came to my mind because there are at least two such pairs in my native language.  Edit: IMO this is not a duplicate of auto-antonym. The auto-antonym examples from the linked pages don't meet my criteria. However I was unaware that list questions are automatically "too broad". Thanks Andrew Leach for explaining me that, I think I will try a community wiki question then.

I am looking for a list of all English words that are their own antonyms. Off the top of my head, I can only think of "either", "fast", "to dust" and "to lease", but there must be dozens more. Can you provide a link to a comprehensive list, if such exists?  Also, what are such words most commonly called? I like the term "Janus word" I once heard, but is that widely understood?  Edited by popular demand to make it absolutely clear that this is not a community wiki poll.


I'm setting up Membership on my ASP.Net website. I'm using a remote database. I have created membership tables on this database by using aspnet_regsql.exe.  When I click security, I get this error on ASP.Net Web Application   I clicked Choose Data Source, but there is not an option to be able to set my remote database. What I'm missing ?  How I can fix this error ? Thanks in advance

When starting a new project that required the use of membership providers I found that I could not connect to a remote database that contained the membership database.  I ran aspnet_regsql and was able to create the membership database on the remote server but when I go to ASPNET Configuration (cassini development server) it will not connect to the remote server.


I have standard Ubuntu 16.04 droplet over digitalocean with LAMP stack. By default I have one user with root privileges (for admin use). I access any directory from root through ssh like with filezilla or netbeans. It all works fine as it should upto this.   I need more users created so that I can configure them to be able to access a particular vhost directory say like /var/www/html/domain2.com  or probably only /var/www/html/*  Also I need to be sure that doing so will not affect any Apache related permissions on folders and files. Say if I create a folder say uploads from user1 and www-data user cant read or write into that folder uploads.  How can I do this ?

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 am just learning Blender 2.82. In the tutorial, it lists 4 different choices when you add - Armature. I don't get any choices I can only place a single bone. No human armature is available to me. What am I not doing?

I did try searching for this but didn't find anything.   I've been following some tutorials for Rigging and have seen a lot of videos showing  Armature Templates available from the Armature sub option see attached.  On the version of blender I'm using 2.8 Beta Win 10 64 bit (23 April 19) I have no options to select anything.  Only the Armature menu heading is from the ADD option  which when selected provides a single bone.  Have these other options gone now or do I need to configure something within blender?  Thanks


Background for the question: in my campaign, I have a Mummy being controlled by a group that includes an Illusionist.  I need to make the Mummy appear as if he is a certain human NPC.  I know I could use True Polymorph, but I don't want to have to have to make the controlling Illusionist that high of a level. My question:  Would the 5th level spell Seeming accomplish what I am trying to do?  I do not need the Mummy to speak or really do anything other than sit there and look like a human.  The text for the spell says that it changes the targets appearance; would this be adequate or would I need to use True Polymorph?

I understand that the effect of this spell is purely visual and will not stand up to physical interaction or extended inspection. But I’m wondering how specific a disguise one can make?   For example, if you are trying to break out of a prison can you only make yourself look like a generic guard or could you make yourself look like the warden himself including facial features (if you’ve seen him before)? Would it be good enough to convince someone who knew him?


When I try to start up Unity Tweak Tool in 14.04, it throws up a window that says:  "The following schema is missing:  com.canonical.unity.webapps  In order to work properly, Unity Tweak Tool recommends you install the necessary packages."  I have no removed this package, I only turned them off in the Privacy settings.  However, looking in Synaptic doesn't show these to even try to reinstall them.  I have no idea why these would be missing.  Any help would be greatly appreciated.


I am trying to create a filtered list of seat nos starting from G only, from a main pool of seat nos A1,A2....B1,B2...etc. However, when i try to sort the list, its not happening, plz help:  My code:  import java.util.ArrayList; import java.util.List; import java.util.Random;  public class Main {      public static void main(String[] args) {          List<String> Seats = new ArrayList<String>();          Random rand = new Random();          //Creating Alphanumeric seatnumbers e.g A1, A2, A3....B1,B2...etc using ASCII values         for(int i =0;i<100;i++)         {             String seatNum = Character.toString(rand.nextInt(35)+65) + (rand.nextInt(14)+1);              if(!Seats.contains(seatNum))              Seats.add(seatNum);          }          //Create a filtered list of only seat numbers starting with G           List<String> gSeats = new ArrayList<>();               Seats.forEach(seat->{                  if(seat.startsWith("G")   )                 {                     gSeats.add(seat);                 }             });             System.out.println("Original G list");             gSeats.forEach((String g)-> System.out.println(g));              gSeats.sort((String g1,String g2)-> g1.compareTo(g2));              System.out.println("\n\nSorted List\n");             gSeats.forEach((String g)-> System.out.println(g));        }  }   The output :    Please help where am I going wrong ?

I need to write a Java Comparator class that compares Strings, however with one twist.  If the two strings it is comparing are the same at the beginning and end of the string are the same, and the middle part that differs is an integer, then compare based on the numeric values of those integers.  For example, I want the following strings to end up in order they're shown:   aaa bbb 3 ccc bbb 12 ccc ccc 11 ddd eee 3 ddd jpeg2000 eee eee 12 ddd jpeg2000 eee   As you can see, there might be other integers in the string, so I can't just use regular expressions to break out any integer.  I'm thinking of just walking the strings from the beginning until I find a bit that doesn't match, then walking in from the end until I find a bit that doesn't match, and then comparing the bit in the middle to the regular expression "[0-9]+", and if it compares, then doing a numeric comparison, otherwise doing a lexical comparison.  Is there a better way?  Update I don't think I can guarantee that the other numbers in the string, the ones that may match, don't have spaces around them, or that the ones that differ do have spaces.


I have a Chromebook and have installed Unity 16.04 on the device. I cannot seem to copy and paste into the terminal as it is a laptop and does not have a mouse button which, when I looked, seemed to be required for copying and pasting.

Is there a way to copy the currently written content of the bash prompt? Say I wrote:  ping www.google.com   so that the lines in terminal looks like:  petr@sova:~$ ping www.google.com   and didn't hit return yet. I want to copy that text to clipboard. Is that possible?  The usual usecase would be hitting up several times and finding a command which I want to copy.


In Chapter 4 of Harry Potter and the Deathly Hallows (The Seven Potters) Voldemort was flying unaided, which meant it must have been done with the use of a spell.   Fast forward to Chapter 30 (The Sacking of Severus Snape). Snape jumped out of the window and flew off while McGonagall and the other teachers where in hot pursuit of him. Harry, rather hopefully, wondered if he had jumped to his death. McGonagall, rather gloomily, remarked that alas, he had his wand when he jumped and could employ the ability to fly, a skill he no doubt learnt from his master. She also noted that this situation was unlike Dumbledore's final moment when he was wandless, and thus, could not jump from the ramparts of the highest tower to fly away from Draco Malfoy and the other Death Eaters.  So, this all implies that you do need a wand to fly.   Voldemort started out with a wand but after Harry's wand destroyed it, Voldemort was rendered wandless. You may recall that he was demanding Selwyn's wand.  In short, my SPECIFIC question is: how did he remain airborne without a wand? Side question: did J.K. Rowling ever comment on this extraordinary ability of unaided flight?

In the seven books, flying is an ability we only see from Voldemort and Snape. Why is that so? and How do they do that?  Moreover, why couldn't anyone in the Order of Phoenix fly?


We're currently learning about induction in my real analysis course. I came up with the following proof that is obviously false but cannot quite figure out why it fails. Here it is...  "Any set $S$ of $n \in \mathbb{N}$ integers are equal."  Proof: For $n = 1$, we only have a single integer in $S$, and thus it is equal to itself. Assume our statement is true for $n$ integers. Now consider any set of $n + 1$ integers. Without loss of generality they are integers $\left\{ 1, 2, \dots, n, n + 1\right\}$. Consider the sets $\left\{ 1, 2, \dots, n \right\}$ and $\left\{ 2, 3, \dots, n + 1\right\}$. Each of these two sets have only $n$ integers, so they are all equal. But this means $1 = 2 = 3 = \cdots = n = n + 1$, so all integers are equal.

I'm bugged by the following that's summarized on p. 109 of .     False theorem: All horses are the same color.      Proof by induction:      $\fbox{$P(n)$ is the statement: In every set of horses of size $n$, all $n$ horses are the same color.}$   $\fbox{Base Case or $P(1)$:}$ One horse is the same color as itself. This is true by inspection.   $\fbox{Induction Step:}$ Assume $P(k)$ for some $k \geq 1$.   $\fbox{Proof of $P(k + 1) :$}$   Since $\{H_1, H_2, ... , H_n\}$ is a set of $n$ horses, the induction hypothesis applies to this set. Thus, all the horses in this set are the same color.   Since $\{H_2, H_3, ... , H_{n+1}\}$ is also a set of $n$ horses, the induction step likewise holds for this set. Thus, all the horses in this set are the same color too.         Therefore, all $n +1$ horses in $\{H_1, H_2, H_3, ... , H_n , H_{n+1}\}$ are the same color. QED.   The issue the instructor was trying to point out is clearly valid. For the case $n = 1$, there is only ${H_1}$. So this case says nothing about possible overlapping elements of each set of $(n + 1)$, for instance $H_2$ in the above proof.    But it was proposed in the class discussion that this was the only problem. Had you been able to prove $P(2)$ true, then a proof of the above format would have been fine.    My interpretation is that yes, you could prove all horses are the same color, if you can prove that any set of two horses will be the same color. But this format would not work.  Why not? The problem I see is that the above proof is for the existence of at least one particular pair of sets of horses of sizes $n$ and $n + 1$, such that in each set, all horses are the same color.  Particularly when the set of size $n$ is a subset of the set of size $n + 1$.  In order to prove the induction step, don't you need to prove that sets of sizes $n$ and $n + 1$, do not necessarily contain the same, overlapping elements?  You could prove that any horse can be added to a set of 2 horses.  Take the last two, and they must be the same color, and so on.  Wwhatever color the first two happen to be, all other horses must thus be the same color.    Am I misinterpreting the example, or am I making a logical error? Thanks in advance.


I apologize if this question has already been asked but I've searched high and low and not found an answer. Commonly, on SO and many other Stack Exchange sites, when I see a post flagged as a duplicate, spam, off-topic, and so on, someone will post a comment like "Off-topic; belongs on Server Fault or possibly Super User". Is this good practice? Should this be done? Is this something the flagger should do after submitting a flag? To me it seems a bit offensive and could garner dispute from an argumentative poster, but that's just my opinion.   As a quick example, a comment like this can be found here:  posted by a Mr. Jim Garrison.

This is related to  question. I think we should discourage "Belongs on S[OFU]" type comments. I think they encourage the OP to go to the indicated site and re-ask the question. Flagging/voting to move on the question should be sufficient. Assuming this is the case, would it be proper to flag those comments for mod removal to hopefully get them removed before a new user sees them and duplicates the question?  Or, another example:    Or, even worse, but this new (!) user probably just doesn't know better:


I want to run   I opened the developer tab in excel, no clue what to do now. I tried creating a "macro button", and then paste the function code in the macro script, but if I press play I get a error related to Private Sub CommandButton1_Click()   and if i try to save the macro, I get this dialog box:

I've seen posts showing answers which use VBA () code/macros, however, I've also noted additional comments afterwards about how to use the VBA (how to implement and execute it). I'm hoping this will help just to get the code executed.   So, my question is:  I have some VBA code. How do I add VBA to my MS Excel or Word or Outlook project?


I have made a massive cube made from hundreds of smaller cubes for a wreaking ball to hit and knock down. I want the cubes to be wood textured. I have my texture on one cube but I want all 700 cubes to be the same texture, there is no way I can go through and texture every single cube. How do I take the texture from the one cube and apply it to all of the other cubes?

I saw a video where the person copied a material from one object to another (Cycles).  How can I accomplish this?


I've recently took my first underwater photos with Olympus TG6 and imported those into Lightroom Classic CC v9.1. All photos were shot in a RAW mode.  Every imported photo has an embedded preview, which looks great ()  But if I go into develop mode, or try to export those photos, or click on the "embedded preview" label or do anything else, the embedded preview goes away and the photos start to look like this:   I understand that embedded preview was pre-calculated by either the camera when a photo was taken or Lightroom when the photo was imported. My question is how can I replicate what I see in the embedded preview and permanently apply the same colour correction to my photos? Is there a collection of preset for Olympus TG6

I'm a novice shooting in RAW and find that half the time my camera JPEG images come out better than my Lightroom tweaks to RAW files.  So to give myself a better start I'd like to apply the JPEG settings that are applied automatically by the camera to my RAW files in lightroom so that initially my RAW files look exactly like the JPEG files.   How can I do this?


I have been having this problem recently. Everytime I add a ppa it says click enter, so it succeeds. Then I need to run sudo apt-get update in order to update the ppa. So when I run this this comes up.

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


A stick of length $2$ m is made of uniformly dense material. A point is chosen randomly on the stick and the stick is broken at that point. The left portion of the stick is discarded and now again another point is chosen randomly on the remaining right portion of the stick and the stick is broken again at that point and the left part is again discarded.The process is continued indefinitely.What is the probability that one of the discarded left parts has length $>1$ m?  Formulating this problem we basically have a sequence of random variables {$X_n$} where $X_1 \sim U(0,2)$ , $X_2|X_1 \sim U(0,2-X_1)$,$X_3|X_1,X_2 \sim U(0,2-X_1-X_2)$ and so on. The probability that any one of the discarded parts is more than $1$ m is equivalent to say that it is $1-P(\cap${$ X_i<1$}) But I cannot find the probability explicitly as it is dependent on $X_1$. Help!

We have all heard the old problem about forming a triangle from breaking a stick into three pieces, with the breaks randomly distributed. Some variations make the second break contingent on the first in some way. I present a new variation (not original to me).   Problem: Take a stick and break it at a location selected with uniform density along its length. Throw away the left-hand piece and break the right-hand one at a location selected with uniform density along its length. Continue forever. What is the probability that one of the discarded left-hand pieces is more than half as long as the original stick?  I do not have a particularly elegant to solution to this one, and was wondering if one exists. Of course, any answers that solve the problem are welcome.


If I install Ubuntu 18.04 LTS on Windows partitions will it remove my media files?  If it removes them, then how to get rid of this problem?

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I am learning the use of tikz. Your help is very impressive. I have to complete my drawing soon and its gives me difficulty to fix the positions of points from where to start and where to go. Would you suggest me at least one of the two plots at your earliest? I will be much benefited if you kindly help me for this.    \documentclass{article} \usepackage{tikz} \usetikzlibrary{   decorations,   decorations.markings,   hobby, }  \begin{document}  \begin{tikzpicture}[use Hobby shortcut, scale=1.5]      \draw[thick] (0.4, 0) .. (0.8, 0.3) .. (1.0, 0) .. (0.4, 0);     \draw  (-.3 ,1).. (0, 0) .. ( 1.2 , 0 )      \draw  (-.3 ,-1).. (0, 0) .. ( 1.2 , 0 ) .. ( 0 , 0 ) ;      \draw   (.5, 0) .. ( .8 , 0 ) .. ( .6 , 0 ) .. ( .7 , -0.012);      \draw (-.1, 1)..(-.08, .7)..(-.05, .4)..( .1 , .4 )..( .7 , .6 )..( 1.4 , 0 )..( .7 , -.6 )..( .2 , -.4 )..(-.1,-.5)..(-.11 ,-.8);     \node[inner sep=1.5pt,circle,fill=red] at  ( .7 , -0.01) {};     \node[rotate=0] at  ( 1.2 , -0.7) {\scriptsize H};     \end{tikzpicture} \end{document}   This is for the 2nd.

Help me to plot the following plot using Hobby.   I have tried to plot it. My code is  \begin{tikzpicture}[use Hobby shortcut]  \draw (-.3 ,1).. (0, 0) .. ( 1.2 , 0 ) .. ( 0 , 0 ) .. (-.3 ,-1);  \draw (.45, 0) .. ( .9 , 0 ) .. ( .6 , 0 ) .. ( .7 , -0.01); \draw  (-.15, 1.2).. (-.01, .2) ..(.01, .22).. (.6, .1) .. ( 1.3 , 0 ) .. ( 0 , -.1 ) .. (-.3 ,-1.2); \node[inner sep=1pt,circle,fill=black] at  ( .7 , -0.01) {}; \end{tikzpicture}   Please correct my code to get the desired fig. Also I want to write HL adjacent to the Fig.


This question was asked in my number theory quiz, but I am unable to solve it.  Let $a, b, n$ be positive integers such that $n$ divides $a^n -b^n $. Prove that $n$ also divides $ \dfrac{a^n -b^n}{a-b}$.  I started by writing $ a^n -b^n  = (a-b) ( a^{n-1} +... + b^{n-1} ) \equiv 0 \mod n $ . But I don't understand what can I do from it and which result should be used. Can you please help. Thank you!!

How does one prove that if $n \mid (a^{n}-b^{n}) \ \Longrightarrow$ $ \displaystyle n \mid \frac{a^{n}-b^{n}}{a-b}$ where $a,b, n \in \mathbb{N}$.  What i thought of is to consider $$(a-b)^{n} \equiv a^{n} + (-1)^{n}b^{n} \ (\text{mod} \ n)$$ and if we suppose that $n$ is odd then we have, $$(a-b)^{n} \equiv a^{n} -b^{n} \ (\text{mod} \ n)$$ and since $n \mid (a^{n} - b^{n})$ we have $$(a-b)^{n} \equiv 0 \ (\text{mod} \ n) $$  I think i am far away from the conclusion of the problem, but this is what i could work on regarding the problem.


I have a log.txt file with various lines of strings and information.  I want to write a script to read the log.txt file line by line and any line that contains the word debug I want to put that line into a new file called debug.txt and all other lines should go to info.txt.  What is the best way to go about doing this? I tried to do a while loop but couldn't figure it out. Thanks

Is there a script/program/utility already available for the following requirement in a optimised way?  someCommand |    tee >(grep "pattern" > LinesWhichMatch) |    grep -v "pattern" > LinesWhichDoesNotMatch


This exercise is from Arfken mathematical methods for physicists): "The function $f(z)=u(x,y)+iv(x,y)$ is analytic. Show that $f^*(z^*)$ is also analytic."  There must be some simple proof (and not related to series), because there is little said about complex analysis in the book before this exercise (The only important thing said is Cauchy-Riemann conditions). Not sure, but I think if $f(z)=u(x,y)+iv(x,y)$ then $f^*(z^*)=u(x,-y)-iv(x,-y)=g(x,y)+ih(x,y)$. Now $g$ and $h$ must satisfy the Cauchy-Reimann conditions and their first partial derivatives with respect to $x$ and $y$ must be continuous. Yet I can't show any of them. Any suggestions for developing this idea?

I came across this question whilst doing some research into complex analysis, and I just can't see what to do!  Let $f(z)$ be a holomorphic function on $\mathbb{C}$. Show that $\overline{f(\overline{z})}$ is holomorphic, whilst $f(\overline{z})$ is holomorphic if and only if $f(z)$ is constant.  I know that holomorphic means that the function is differentiable everywhere, and I need to apply the Cauchy-Riemann equations somehow, but I'm not sure how to approach this.


I have a file and I want to know its size. On computer 1, I get:  $ ls -lh file > -rw-r--r--. 1 user group 441 May 30 15:41 file   On computer 2, I get   $ ls -lh file > -rw-r--r--. 1 user group 441 May 30 15:41 file   Okay. They agree. The filesize is 441 bytes. But now I use du on computer 1:  $ du -h file > 1.0K    file   and on computer 2:  $ du -h file > 32K    file   Why do they not agree? I assume it has something to do with the cluster size on the filesystem. Now a folder with several subfolders and files and a total size of several 100 Megabytes is about twice as large on computer 2 than it is on computer 1. Why would one use the cluster size as it is on computer 2? It will take up much more space, depending on the typical file sizes.  Filesystem on computer 1 is afs, filesystem on computer 2 is nfs.

I have a directory with a few hundred files (real files, no symlinks, no subdirectories).  When I use ls -la and sum up the sizes in Excel I get 287190 bytes(?).  When I use du -b or du --apparent-size --block-size=1 I get 422358 bytes(?).  I thought those two things mean the same thing, why the difference?


Ever since we moved our site to a SPA architecture (SSR based, Vue+Nuxt), google chose to completely ignore our carefully written page titles and meta descriptions. Obviously we checked the sources, all html tags are correct in the right places, but google chose to completely ignore / change them. (other search engines show correct titles/descs).  Weirdly, in most cases, when it comes to page titles, it uses parts of of what we provide, but moves the kw which is used as first word, and creates a suffix from it.  This might explain us jumping up and down in serps for our 3 main keywords.   Here is an example: One of our pages, where 'Fotowoltaika' is the main KW, and title we set is  "Fotowoltaika - kalkulator opłacalności w 2020 roku"  Google result:    Meanwhile, in source of this very page:    Page itself:   On this particular page, description is preserved, but on dozens other pages they're completely ignored. Which is quite common on all sites, when google thinks it's smarter than content writers, but I've never seen Google changing titles like this. In most cases google-changed titles do not make any sense grammatically, for sure affecting our CTRs.  Has anyone ever come across a situation like this? Any help, hits, ideas would be greatly appreciated..

I'm just wondering how it is possible that IGN.com has this in its title tag:      Video Games, Cheats, Walkthroughs, Game Trailers, Reviews, News, Previews & Videos at IGN   while on Google its title is simply "IGN".   How can one achieve such a thing? Does it use some special meta tag I can't see?


In my previous questions like 'how do compressions and relaxation carry energy...' and 'how are they not isothermal...' and 'where does the heat come from in the compressed gas...',i've made  enquiries reagarding the phenomenon of sound energy propagation and got answers from experts.So i am now writting my concept:when a vibrating fork compresses the air,it does work on it increasing the K.E. of the layer.When the fork goes opp. side,it works on the compressed layer and relaxes it increasing theP.E.Meanwhile,during expansion,the layer works on the next layer and compresses it using the excess kinetic energy.And the next layer does the same to its next layer by compressing using that K.E. given to it by the fork via the first layer.Ultimately,the last layer works on our ear drum to produce sound using the kinetic energy.The question is am i right in my assumption?Plz help...

Suppose a vibrating fork exerts force to the air particles to compress which leads to the increase of internal energy (heat).This heat or energy given by the fork is given to the next layer of air and in this way, this energy makes sound. But if it was so, it will be isothermal. And Laplace told it was adiabatic. How can it be? I am confused. The heat energy infact is the energy given by the fork. If it is adiabatic, how can the air pass this energy ?


Suppose I want to:   compile and install my own custom application which requires downloading, compiling and installing the source for newest version of libthrift which requires downloading, compiling and installing the latest version of libboost   Here, I'm installing these libraries in my system which may interact with other packages -- very many libraries depend on libthrift and libboost.   installing these may break existing package installed with apt-get/yum   Also, if I later run apt-get or yum:   my custom libthrift and libboost will be overwritten breaking my custom application that depends on custom versions of these libraries.   So, what's the solution here? I don't want to install into /home (I'd like the packages to be available to shared users in a code regression build cluster). I've also read that /opt is not really for this purpose (the packages installed should be , which they are not). The  I've found seem to cover this case in enough detail.

I need to compile some software on my Fedora machine. Where's the best place to put it so not to interfere with the packaged software?


I have Dell inspiron 3521 and Ubuntu 12.04. Wireless is working perfectly but bluetooth does not detect any device. result of sudo rfkill list is  0: hci0: Bluetooth Soft blocked: no Hard blocked: no   1: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no 2: brcmwl-0: Wireless LAN     Soft blocked: no     Hard blocked: no  Please help me regarding this. Thank You.

Bluetooth is on but can't find or be found by any other devices.  Output of sudo service bluetooth status:  ● bluetooth.service - Bluetooth service    Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)    Active: active (running) since ხუთ 2015-06-04 22:33:18 GET; 13min ago  Main PID: 26678 (bluetoothd)    CGroup: /system.slice/bluetooth.service            └─26678 /usr/sbin/bluetoothd -n  ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPAG ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPHS ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSource ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSink ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPAG ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPHS ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSource ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSink ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Adapter /org/bluez/26678/hci0 has been enabled ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Adapter /org/bluez/26678/hci0 has been enabled   Output of lsusb:  Bus 003 Device 005: ID 0a5c:21d7 Broadcom Corp. BCM43142 Bluetooth 4.0   How can I fix it?


I am trying to learn R generally and making statistics for maps. I found some useful tricks for making maps with it but it is not the best you can do. My everyday GIS program is ArcGIS.  How I can use R in ArcGIS?  A tool I use is the GME plugin. Is this the only way?  I tried to use R in QGIS but a plugin I found never worked.

I've used the integration of  with QGIS, and found it a very uesful tool. Having taken a look at the R toolbox  and the  it appears they both offer only point clustering to demonstrate the proof of concept.   Can other analysis methods available in R be implemented in ArcGIS Desktop through a python script (for example, implementing specific parts of the  package)?


I'm writing a statistics program which will maintain a list of float values. The program will implement the following menu:   Add value to list Delete value from list (by value) Delete value from list (by location in list) Display list Exit   I've written everything except the third option. I can't figure out how to get it done. How would one do that?

How do I remove an element from a list by index in Python?  I found the list.remove method, but say I want to remove the last element, how do I do this? It seems like the default remove searches the list, but I don't want any search to be performed.


Given a countable set on which a total ordering is defined, it is not always possible to list the full set in ascending order. The set of rationals is a well-known example.    But are there conditions under which such a listing is possible? Ideally, the conditions would be both necessary and sufficient conditions, but I suppose weak sufficient conditions will, eh, suffice. For instance, can the support of a discrete random variable on a probability space always be listed in ascending order?

This is problem #6 from Section 1.2 of Ash's Real Variables With Basic Metric Space Topology.   I am asked to show that it is impossible to list the rational numbers in increasing order.   While I know it is possible to list a finite subset of the rational numbers in increasing order, I was wondering if the reason for the impossibility in this case is because there is no least element of $\mathbb{Q}$?   I mean, it's possible to impose an ordering on $\mathbb{Q}$ (correct me if I'm wrong, but it seems possible to compare any two rationals).  But the set $\mathbb{Q}$ is of course, a subset of itself, and the Well-Ordering Principle says that a set $S$ is Well-Ordered only if any subset of $S$ contains a minimal element. Since $\mathbb{Q}$ does not contain a minimal element, it does not appear that it is a Well-Ordered set.   Is this the correct idea as to why it's impossible? If not, could somebody explain to me what the correct idea is and a strategy for proving it?  Thank you ahead of time.


I've set extensions.pocket.enabled to false in about:config.  is still displayed as enabled in about:support > Extensions:  Pocket | 1.0.5 | true | firefox@getpocket.com      (the accepted answer is outdated and and about group policy disabling method)

Firefox announced that their new version would be integrated with Pocket. I would like to disable this for my users in my domain.  What is the best way to do this?


my MacBook Pro hard drive died (after dropping) I can see the disk when I book from DVD but I don't want to format not to lose data.  What is the best way to recover data? (what hardware and software if any I need)  I have other IMac and Windows computers

What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:


Here is two numbers $q$ and $k$. Tell me please what does mean this notation $q \mid k$? Are they relatively prime or something ?

In the computational topology literature, the reduction algorithm for computing the Smith normal form of a boundary matrix uses the notation $b_j > 1 \: \text{ and }\: b_j\mid b_{j+1}$ in the context of the diagonal elements of the Smith matrix. Can anyone give me an idea for what it means?


I'm setting up a program that uses 'DFS' as a child class of 'Search', and calls its base constructor.  The program runs fine, until the breakpoint I placed just after calling the constructor, in which I receive the error:   Exception thrown: read access violation. _Pnext was 0xCCCCCCD0.  I've tried to summarise the code to only what is important.  in main.cpp:  DFS search(gridSize, startPoint, endPoints, walls);   in Search.h:  public:     Search(unsigned int gridSize, unsigned int startPoint, unsigned int endPoints[2], vector<int> walls);   in Search.cpp:  #include "Search.h"  Search::Search(unsigned int gridSize, unsigned int startPoint, unsigned int endPoints[2], vector<int> walls) {     sGridSize = gridSize;     sStartPoint = startPoint;     sEndPoints[2] = endPoints[2];     sWalls = walls; }   In DFS.h:  #include "Search.h"  #include <vector>  public:     DFS(unsigned int gridSize, unsigned int startPoint, unsigned int endPoints[2], vector<int> walls);   In DFS.cpp:  #include "DFS.h"  DFS::DFS(unsigned int gridSize, unsigned int startPoint, unsigned int endPoints[2], vector<int> walls) : Search(gridSize, startPoint, endPoints, walls) {  }   If any more code is needed to understand this, just ask - I'm worried about pasting in too much.  Any help is greatly appreciated :)

I know that the compiler will sometimes initialize memory with certain patterns such as 0xCD and 0xDD.  What I want to know is when and why this happens.  When  Is this specific to the compiler used?  Do malloc/new and free/delete work in the same way with regard to this?  Is it platform specific?  Will it occur on other operating systems, such as Linux or VxWorks?  Why  My understanding is this only occurs in Win32 debug configuration, and it is used to detect memory overruns and to help the compiler catch exceptions.  Can you give any practical examples as to how this initialization is useful?  I remember reading something (maybe in Code Complete 2) saying that it is good to initialize memory to a known pattern when allocating it, and certain patterns will trigger interrupts in Win32 which will result in exceptions showing in the debugger.  How portable is this?


I have added Elements using Jquery inside PHP after loading them from the database. Each button has two classes, one controlling the GUI and another controlling the Click for particular button. The code is as under       echo "<script type='text/javascript'>$('.main').append('<button class=b_ui b$index>Change</button>'); </script>";   Now if I check the classes from Inspect Element  perspective of the browser, it shows 2 classes. But when I click on it and get class of element using this code   $('.b_ui').click(function() {     cls = $(this).attr('class');     alert('no. '+cls); }   It shows only first class (GUI) and not the other which I want to use for handling click. Any help ?

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


In this quoted example, is it okay to shift verb tenses mid-sentence?  Background: The narration is written in present tense. The narrator is referencing something that was said in the past, but the information in that sentence is presently true.  Version 1:     She said the world would never be the same now that we   knew angels were real. I'm not so sure.   OR Version 2:     She said the world will never be the same now that we   know angels are real. I'm not so sure.   OR Version 3     She said the world would never be the same now that we   know angels are real. I'm not so sure.   Thank you for your insights.

Do tenses in a time clause never back-shift in reported speech?  For example, does      "I went to Italy when I finished school."    become      She said she had gone to Spain when she finished school.   -or-   She said she had gone to Spain when she had finished school.   and does      "I will go to Italy when I finish school."    become     She said she would go to Italy when she finishes school.   -or-   She said she would go to Italy when she finished school.


The sentence is:  "Despite its ability to hijack your senses and immerse you in hyper-realism, the real power of VR may lie in its ability to foster quiet intimacy so realistic it’s unsettling."  I'm really confused with this sentence. I think there is an omitted part after "realistic" or something else. I assume it should be "so realistic that it's unsettling" without omission, am I right?

He will understand that I was not joking.   He will understand I was not joking.  Which of the sentences is correct? Are there any specific rules about the use of "that" in the sentences I reported as example?


I can't boot to the Ubuntu 14.10 ISO I have on my drive (running Ubuntu 14.04 as my main OS btw). I added these lines to the bottom of /etc/grub.d/40_custom:  menuentry 'ubuntu-iso' {     set isofile="/boot/ubuntu-14.10-desktop-amd64.iso"     loopback loop (hd0,1)$isofile     linux (loop)/casper/vmlinuz.efi boot=casper iso-scan/filename=$isofile noprompt noeject     initrd (loop)/casper/initrd.lz }   The Ubuntu ISO is at /boot/ubuntu-14.10-desktop-amd64.iso, and I've verified its checksum. /dev/sda1 is mounted at /boot, which is why I've done (hd0,1)$isofile above.  Then I run sudo update-grub. The new menu entries show up in the grub menu screen, but when I select it and try to boot it just boots to my existing OS instead of the ISO.

I don't want to burn a CD, DVD or USB memory stick. And I don't care about saving the existing operating system (Linux Mint). I want to install Ubuntu (actually Kubuntu 12.04 LTS) to the computer directly from the ISO image. The image is for the Kubuntu Live DVD (3.5 GB).  The computer is now booted into Linux Mint. A set of command line steps would be satisfactory. In my mind, I simply need to trick the existing system into thinking I inserted a CD/DVD, right?  I know there is a similar question already but it does not have a good answer. The answer basically says, "see this link." I reviewed the link and I decided that StackExchange needs a good answer to this question. Furthermore, most answers at other places on the Internet assume the user is coming to Ubuntu from Windows. So I think this question is one that needs a good answer here. Thanks


I was thinking about the definition of the conservation of momentum, which says that momentum is conserved unless outside forces are acting on the system, and I was wondering that if the system is the universe, if momentum must be conserved.  To put it more clearly, is momentum in the entire universe conserved?  (I know about the second law of thermodynamics, but I do not think that it applies if we are considering individual particles since there are no "heat losses" at that level (elastic collisions in Kinetic Molecular theory, etc).)

In popular science books and articles, I keep running into the claim that the total energy of the Universe is zero, "because the positive energy of matter is cancelled out by the negative energy of the gravitational field".  But I can't find anything concrete to substantiate this claim. As a first check, I did a calculation to compute the gravitational potential energy of a sphere of uniform density of radius $R$ using Newton's Laws and threw in $E=mc^2$ for energy of the sphere, and it was by no means obvious that the answer is zero!  So, my questions:   What is the basis for the claim – does one require General Relativity, or can one get it from Newtonian gravity? What conditions do you require in the model, in order for this to work? Could someone please refer me to a good paper about this?


when i enter the password "ahmad" the code doesn't execute as it true, i don't know what is the problem   but if i define variable pass = "ahmad" it is working very well  but i want to make the user enter the password by himself   public class main {  static Scanner uinput= new Scanner(System.in);  public static void main(String[] args) {       String pass;      while(true){      System.out.print("Enter the password: ");     pass= uinput.nextLine();      if(pass== "ahmad"){         System.out.println("It is working");     }      else System.out.println("failed");      }  }   here is the console result:  Enter the password: ahmad failed Enter the password:

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 created a script, and I want it to be rwx only by root. All other can only x. What I have now  [root@localhost /]# chmod 755 scripts/ -v mode of 'scripts/' retained as 0755 (rwxr-xr-x) [root@localhost /]# chmod 711 scripts/macchange -v mode of 'scripts/macchange' retained as 0711 (rwx--x--x)   And I think all is good here. If I go with my user I can read the folder content, but not the files. But when I'm trying to exec the script this is what I get  [iron@localhost /]$ ./scripts/macchange  /bin/bash: ./scripts/macchange: Permission denied   What am I doing wrong? If I give my user permission to read it suddenly works.  Explanation why it's different then the possible duplicate: I didn't realize bash needs to read the file to execute it. I thought it's an issue of folder to file permissions.

Is it possible to execute a script if there is no permission to read it? In root mode, I made a script and I want the other user to execute this script but not read it. I did chmod to forbid read and write but allow execute, however in user mode, I saw the message that says: permission denied.


The answer to the equation :  $$\log_3x+\log_2x+\log_4x=1$$    my try :  $$\log_3x+\log_2x+\log_4x=1\\ \log_2x+\log_2\sqrt{x}+\log_{3}x=1\\\log_2x\sqrt{x}=\log_{3}{\dfrac{3}{x}}$$  now ?

I am looking for a close form solution for below equation.  $$\log_{2}{x}+\log_{3}{x}+\log_{4}{x}=1.$$   I solve it by graphing, but I don't know is there a way to find $x$ analytically  ?


I know there are many related questions, however I couldn't find any other way to get help on this problem:  On my CentOS VM I made a custom script for my bash prompt in /etc/profile.d/custom.sh  PS1="\n\e[0;97m\][\D{%d%m%y-%H%M}][\u@\h \W] \n\e[m\]\$ " export PS1   My bash now looks like this:    However If I type a long command and if I want to get the cursor on the first position using CTRL-A this is what happens:  Typed something long. I want to change something at the beginning of the line so I will press CTRL-A to get the cursor at the first position:    After pressing CTRL-A:    Now if I try to delete the whole line with DEL or BACKSPACE this is the end result?    No matter how much I try to delete those 4 chars they always stay until I hit the ENTER key. Those last 4 chars are always displayed but it is like they don't exist.. I am free to type commands and they will be ignored:    At the last picture I successfully executed cd /var command and now the bash is like it is intended.  Any thoughts?

Often when I start looking at history of commands some of the characters from a command displayed aren't erased, for example:  What's happening:  prompt$ some_command prompt$ some_commanother_command   What should have happened:  prompt$ some_command prompt$ another_command   I can't erase those characters and bash ignores them when executing the command. They also disappear when a new prompt is being displayed (after pressing Enter for example).  I asked other people who work on Linux at my workplace and they said that they have that problem sometimes too, but they didn't have an idea on how solve that issue.  I have Ubuntu 11.10 and I'm using guake. Here is my PS1:  \e[0;31m\u \A ${PWD##*/}\e[0;32m$(parse_git_branch)\e[0;31m$\e[m   where parse_git_branch is  parse_git_branch () {     git name-rev HEAD 2> /dev/null | sed 's#HEAD\ \(.*\)# (\1)#' }   As far as I know my colleagues have that problem even with less "fancy" PS1.


I posted a video early where I asked the question about opposing laser beams appearing to turn one laser off. Further experiments, however, have demonstrated that it is interference at play not that one laser quits working. Yet, two separate lasers do not create the destructive interference to the extent that my experiment shows. The experiment is two lasers beams facing directly into each other with a 45 degree beam splitter between them. One beam disappears. What happening? I posted two videos to show what happens

When I send two separate laser beams directly into each other one of the beams goes completely out. These are inexpensive 5mv red diode lasers. What’s happening inside the laser to make it “turn off”? When the beams are not opposing the “turned off” laser returns to its normal function.  Note: The use of a a beam splitter allows me to see effects. Update here are two videos I posted showing my experiment results.


Consider $$\int_{-1}^{1}\frac{\sqrt{(1-x^{2})}}{1+x^{2}}dx$$ I have a problem with this integral; the method I know consists in calculating the complex integral of $$f(z) = \left( \frac{z-1}{z+1} \right)^{\frac{1}{2}} \frac{1+z}{1+z^{2}}$$ along the curve formed by the " shrinking dogbone contour" withe centres $\{-1,1\}$ and the circumference of radius $R \rightarrow \infty$. But I obtain $0$, impossible. What's wrong with this method ?   In particular, what are the residues of $f(z) $ in $\{-i,i\} ? $

I'm trying to evaluate the integral $$ I =\int_{-1}^{1}\frac{\sqrt{1-x^{2}}}{1+x^{2}} \, dx $$ by using a dumbbell/dogbone contour, but I'm having difficulty determining the residue at infinity.  I started by defining  $\sqrt{1-z^{2}}=\sqrt{(1-z)(1+z)} $ so that it is a well-defined function if the line segment $[-1,1]$ is omitted.  Similar to an , I choose the branches where $0 < \arg(1-z) \le 2 \pi$ and $-\pi < \arg(1+z) \le \pi$.  Then I integrated $ f(z) = \frac{\sqrt{1-z^{2}}}{1+z^{2}}$ clockwise around a dumbbell contour.  Just above the branch cut, $\arg(1-z) = 2 \pi$ and $\arg(1+z) = 0$.  And just below the branch cut, $\arg(1-z) = 0$ and $\arg(1+z) = 0$.  So the integral evaluates to $-I$ both above the cut and below the cut.  Since the integrand is meromorphic outside the contour, I get  $$ - 2I =  2\pi i \left( \operatorname{Res}[f,i]+ \operatorname{Res}[f,-i]  + \operatorname{Res}[f,\infty] \right),$$ where  $$\begin{align}  \operatorname{Res}[f,i] &=\lim_{z\to i }\frac{\sqrt{|1-z|e^{i\arg(1-z)}\ |1+z|e^{i\arg(1+z)}}}{z+i} =\frac{\sqrt{\sqrt{2}e^{\frac{7\pi i}{4}}\sqrt{2}e^{\frac{\pi i}{4}}}}{2i} \\ &=\frac{\sqrt{2}e^{\pi i}}{2i}=-\frac{\sqrt{2}}{2i}, \end{align}$$  $$ \begin{align}\operatorname{Res}[f,-i] &=\lim_{z\to-i }\frac{\sqrt{|1-z|e^{i\arg(1-z)}\ |1+z|e^{i\arg(1+z)}}}{z-i}=\frac{\sqrt{\sqrt{2}e^{\frac{\pi i}{4}}\sqrt{2}e^{\frac{-\pi i}{4}}}}{-2i} \\ &=\frac{\sqrt{2}e^{ 0\pi i}}{-2i}=-\frac{\sqrt{2}}{2i}, \end{align}$$ and  $$ \begin{align}\operatorname{Res}[f,\infty] &=\operatorname{Res}\left[-\frac{1}{z^{2}}f\left(\frac{1}{z}\right), 0 \right]= \operatorname{Res}\left[-\frac{\sqrt{z^2-1}}{z(1+z^{2})},0\right]\\ &=-\lim_{z\to 0}\frac{\sqrt{z^2-1}}{1+z^{2}} = -(-1)^{\frac{1}{2}}. \end{align}$$  But what is $(-1)^{\frac{1}{2}}$?   I assume it must be $i$, but I don't know how to argue that it can't be $-i$.  EDIT:  There is also the issue that Ted Shifrin mentioned of assuming that $\sqrt{z^{2}}=z$.


I get confused about how to use "a" and "an" correctly. The question of "a" vs "an" should be decided by the pronunciation of the word that follows the article, right?  But I've seen the following sentences on the internet.   {Alternatives to the TOEFL (ACT, SAT, IELTS)—Minimum Score Requirements An ACT English subscore of 21 An SAT Critical Reading score of 540 An IELTS (International English Language Testing System) total score of 6.5, with no subscore lower than 6.0}  I wonder why "an" is used in the sentence "An SAT Critical Reading score of 540". Shouldn't we say "A SAT Critical Reading score"?  Another example, in the following sentence: {The minimum English language requirement of this position is an TOEFL ibt score of 90.}  Shouldn't we say "a TOEFL ibt score" rather than "an TOEFL ibt score"?

99% of the time, I'm clear on when I should use "a" versus "an." There's one case, though, where people & references I respect disagree.  Which of the following would you precede with "a" or "an," and why?   FAQ FUBAR SCUBA   [Note: I've read the questions  and , but the rules given there don't necessarily apply here.]    [Edited to add]  Here's a shorter (and hopefully clearer) version of the question…  In written English, which is correct (and why): "a FAQ" or "an FAQ"?  Some references with differing opinions:   an: the  and  a: the Microsoft Manual of Style for Tech Publications, 3e either: the  and


I have a FreeBSD host with multiple IP interfaces. I would like to have snmpd listen on a single private IP interface, but I am getting the following error when trying to start the service.   Error opening specified endpoint "192.168.200.50"  in my configuration file I have the following line  agentaddress  192.168.200.50   If I remove this line, snmpd starts up fine, but is listening on all interfaces, which I would like to avoid.   I have generated the configuration file with snmpconf, and it fails when I specify the IP address to listen on via the script.   Any thoughts on how to correct this?  This is on FreeBSD 8.3-STABLE and net-snmp 5.7.1  Thanks

I have this monitoring network setting for Net-SNMP 5.7.2.1 listening to multiple Ethernet interfaces on my home gateway but it would only take the following combination from the snmpd.conf configuration file:   single IP address single IP address, protocol-specific single IP address per unique protocol   such as:  agentAddress  127.0.0.1:161   or  agentAddress  udp:127.0.0.1:161   or  agentAddress  udp:127.0.0.1:161,udp6:[::1],tcp:127.0.0.1:161    But it would not accept multiple IP addresses using the same protocol, as given below as desired:  agentAddress  udp:127.0.0.1:161,udp:172.28.130.1:161   How do I make SNMP daemon (snmpd) listen to TWO (or more) Ethernet interfaces


Problem: I wanted to make it a dual boot system, however I am unable to get the machine to boot from either the disc or a bootable USB drive. I have disabled the safe boot mode, but still to no avail. I recently purchased a Dell Inspiron 15 this is the configuration:  Operating System:Windows 10 Home (x64) Version 1909 (build 18363.900)  Install Language: English (United States)  System Locale: English (United States)  Installed: 6/18/2020 12:39:21  Servicing Branch: Current Branch (CB)  Boot Mode: UEFI with Secure Boot disabled  System Model: Dell Inc. Inspiron 3593  System Service Tag: xxxxxxx (support for this PC)  Chassis Serial Number: xxxxxx  Enclosure Type: Notebook  Processor:  1.20 gigahertz Intel Core i3-1005G1  primary memory cache: 160 kilobyte  secondary memory cache:1024 kilobyte  tertiary memory cache:4096 kilobyte  64-bit ready  Multi-core (2 total)  Hyper-threaded (4 total)    Main Circuit Board b  Board: Dell Inc. 0TGVJN A00 Serial Number: /384VT33/CNCMC0005C0388/ Bus Clock: 100 megahertz UEFI: Dell Inc. 1.5.0 12/17/2019   Drives  1046.40 Gigabytes Usable Hard Drive Capacity 994.02 Gigabytes Hard Drive Free Space    PC SN520 NVMe WDC 128GB [Hard drive] (128.03 GB) -- drive 1, s/n   20097B451509, SMART Status: Healthy ST1000LM035-1RK172 [Hard drive] (1000.20 GB) -- drive 0, s/n ZDEJNJS5, rev 1002, SMART Status: Healthy Memory Modules c,d 7960 Megabytes Usable Installed Memory  Slot 'DIMM A' has 8192 MB (serial number 43634603) Slot 'DIMM B' is Empty Local Drive Volumes  c: (NTFS on drive 1) * 46.33 GB 5.11 GB free  d: (NTFS on drive 0) 1000.07 GB 988.91 GB free

This question is asked often in Ask Ubuntu, sometimes with few hints about the situation.   Please provide a list of possible reasons to help troubleshoot the problem.


I have a digital ocean droplet with 1 core 2 gigabytes of RAM. Currently the server uses maybe 10 to 20% of the ram. Is running MySQl, redis, failto ban, exim, dovcot, phpmyadmin, roundcube, nginx reverse proxy and some other stuff. Below is the default settings that it has. I would appreciate any advice on what people think would be the appropriate settings for below on this Droplet. Thank you mpm_prefork_module StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 256 MaxClients 200 MaxRequestsPerChild 4000 mpm_event_module StartServers 2 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxClients 200 MaxRequestsPerChild 4000

This is a  about capacity planning for web sites. Related:      What are some recommended tools and methods of capacity planning for web sites and web-applications? Please feel free to describe different tools and techniques for different web-servers, frameworks, etc., as well as best-practices that apply to web servers in general.


I am not able to solve this problem from many days. It appeared on Final Round of May Challenge on TECHGIG.com. I am asking it here because, it requires strong maths concept of combinations.  Problem Description:  KFC opened just a new outlet. The problem is that its very outer of the main city. A long highway leads to that KFC outlet. Due to very outer position of outlet almost no one stops in it, hence its now unprofitable to hold it now. One of the main reason is that they have not advertised well for their outlet. There are exactly N advertising boards on the highway from main city to this new KFC outlet. Now KFC want to advertise on some of these advertising boards ( Definitely advertising on every board cost some money) .  KFC strategy is very clear, they want that at least 'K' KFC advertisement should be there among M consecutive advertising boards. But at the same time KFC want to pay minimum for its advertisement because already it has spent a lot on its outlet.  Now your job is to help KFC and tell KFC the number of ways different ways in which they can place their advertisement on there boards ( definitely minimum number of advertisement) and still meeting its strategy.   Input/Output Specs: Input Specification: Your input will be Three integers values.  N advertising boards on the highway from main city to this new KFC outlet at least 'K' KFC advertisement should be there among M consecutive advertising boards. N, M and K (1 <= K <= M <= 50, M <= N <= 10^9)  Output Specification: Your output will be total number of possible ways modulo 1000000007. if the input values are invalid then your output will be "-1".

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


I am. You/we/they are. He is. I/he was. You/we/they were. I had been. ... to be. ... being bad. ...   Why are there so many forms for this verb, and why are they so dissimilar? If you go far enough back, was there a time where they were more similar? Did a couple of languages merge in the verb to be?

I read somewhere that English is the only language to have borrowed a form of its to be verb from another language. I want to say, if memory serves, that it was are that was borrowed from an early Scandinavian language. Is that so?  I know Old English had sind for one of their pronouns inflections of be, the same as in German.  But did it switch to are naturally from some other gentler evolution, or was it borrowed?


I know that when a car is taking a turn, the front 2 wheels trace out 2 arcs having the same centre. I also know that the steering angle for the outside wheel is more than that of the inner wheel to prevent the car from skidding. My question is during the turn do the rear wheels trace out the same arcs as the front wheels.

When a vehicle makes a turn, the two front wheels trace out two arcs as shown in the figure below. The wheel facing towards the inside of the turn has a steering angle that is greater than that of the outer wheel. This is necessary to ensure that both front wheels smoothly trace out two arcs, which have the same center, otherwise the front wheels will skid on the ground during the turn.   During a turn, do the rear wheels necessarily trace out the same arcs as the front wheels?


#!/bin/bash docker rm -f $(docker ps -qa) docker rmi -f $(docker images -q) docker volume rm $(docker volume ls -q)  sudo docker run -d --restart=unless-stopped -p 9090:80 -p 9091:443 --privileged -v /opt/rancher:/var/lib/rancher --name=rancher_docker_server rancher/rancher:latest   I want in this part, before sudo docker a question arises whether to continue?

I want to pause input in a shell script, and prompt the user for choices. The standard Yes, No, or Cancel type question. How do I accomplish this in a typical bash prompt?