I'm thinking of buying entry level DSLR Nikon D3500. I haven't used DSLR before, so I'm not sure if it is a good decision to buy DSLR. I would like to know if with this camera I can shoot portraits with blured background such as on the new smartphones with two cameras. Another thing I want to know if buying DSLR is good for beginners in photography and amateur photographers and is it worth the money.  I'm new in this community, so I'm not sure if this is the right place to ask this question.

I'm looking into starting a small at home portrait photography business mostly as a hobby for now, and I'm wondering if the camera I have now (Nikon D3000) is good enough for portrait photography.  I've heard from a few friends who do portraits, weddings, etc. that most of the "photo magic" is really just handled in Photoshop, and how the camera is actually used, and the camera is not the only thing to think about.   Is there a flash or some other add-on I should purchase that will help the camera? I just have the onboard one now. I've signed up for a few classes at our local college, however they won't start for a month, so I want to get a head start on what I should look for in equipment.  Is this camera simply sub-par for this sort of work? Is there a better entry level camera I should look into?


I have JSON response that has date value as below     /Date(1494468000000)/   How can I parse this to Date object without using any library?

I'm taking my first crack at  with jQuery. I'm getting my data onto my page, but I'm having some trouble with the JSON data that is returned for Date data types. Basically, I'm getting a string back that looks like this:  /Date(1224043200000)/   From someone totally new to JSON - How do I format this to a short date format? Should this be handled somewhere in the jQuery code? I've tried the jQuery.UI.datepicker plugin using $.datepicker.formatDate() without any success.  FYI: Here's the solution I came up with using a combination of the answers here:  function getMismatch(id) {   $.getJSON("Main.aspx?Callback=GetMismatch",     { MismatchId: id },      function (result) {       $("#AuthMerchId").text(result.AuthorizationMerchantId);       $("#SttlMerchId").text(result.SettlementMerchantId);       $("#CreateDate").text(formatJSONDate(Date(result.AppendDts)));       $("#ExpireDate").text(formatJSONDate(Date(result.ExpiresDts)));       $("#LastUpdate").text(formatJSONDate(Date(result.LastUpdateDts)));       $("#LastUpdatedBy").text(result.LastUpdateNt);       $("#ProcessIn").text(result.ProcessIn);     }   );    return false; }  function formatJSONDate(jsonDate) {   var newDate = dateFormat(jsonDate, "mm/dd/yyyy");   return newDate; }   This solution got my object from the callback method and displayed the dates on the page properly using the date format library.


double test = 1029 / 9.8; // = 104.99999...     int inttest1 = (int) test; // 104     int inttest2 = (int)Math.floor(test); // 104     double testtt = 9.8 * 105; // 1029.0   1029 / 9.8 equals 105  but Java returns 104.9999...  More serious problem is integer casing result is 104, not 105  Why this happens and how can I avoid this result?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


So I have tried many methods including Laplace transform and differentiation but the p and q seems to be unsolvable, I would like to know how does the form change from the first equation, then substitude the Y = e^t to get the second equation. also my second question is why is how can i solve for p and q if i dont have any initial conditions?

If someone could help me with the proposed change of variables, it would be greatly appreciated. Consider Euler's equation:  $$z^2w'' + \alpha zw' + \beta w = 0$$  where $w$ is a function of $z$ and $\alpha, \beta$ are constants. How would the change of variables $t =\ln(z)$ transform this equation?


Let $\Bbb{R}$ be the set of real numbers. Determine all functions $f:\Bbb{R}\longrightarrow \Bbb{R}$ satisfying the equation $$f(x+f(x+y))+f(xy) = x + f(x+y)+yf(x)$$ for all real numbers $x$ and $y$.

Let $\Bbb R $ be the set of real numbers .Determine all functions $f:\Bbb R \rightarrow \Bbb R $ satisfying the equation   $$f(x + f(x + y)) + f(xy) = x + f(x + y) +yf(x)$$ for all real numbers $x$ and $y$.   My work  $$f(x + f(x + y)) + f(xy) = x + f(x + y) +yf(x)$$ Setting $y=0$ $$f(x + f(x)) + f(0) = x + f(x )$$ $$\implies f(x + f(x))  = x + f(x ) -f(0)$$ $$\implies f(t)  = t -f(0)$$ Setting $x=0$ $$f(f(y)) + f(0) = 0 + f(y) +yf(0)$$ $$f(f(y)) =  f(y) +f(0)(y-1)$$  Setting $y=1$ $$f(x + f(x + 1))  = x + f(x + 1)$$


I know that there are several posts regarding sorts of python lists, but I tried a large bunch of things and didn't accomplish to get what I want.   My code:       list = []     things = re.findall('   <img src="(.*?)" alt="(.*?)" .*?', content, re.DOTALL) for url, image, name in things:     list.append({'url': url, 'image': image, 'name': name})   Now I want to sort this list by name. I found several posts which stated to use list.sort(key=) but I don't know what I should use for the key. Everything I tried resulted in a KeyError.  I'm sorry if I'm duplicating an already solved post, but I can't find the proper solution.   Thanks in advance.

I have a list of dictionaries and want each item to be sorted by a specific value. Take into consideration the list: [{'name':'Homer', 'age':39}, {'name':'Bart', 'age':10}]  When sorted by name, it should become: [{'name':'Bart', 'age':10}, {'name':'Homer', 'age':39}]


i need help how to fix my laptop Dell Inspiron 5737 brightness being stuck at max, when i press keys on my laptop scale shows that it "works" but brightness remain the same at max and it is killing me i have tryed few solutions including this one but without any success  sudo nano /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor" sudo update-grub  can someone please tell me some solution that might work, btw since i am new to ubuntu so please be specific to what i need to do and where as i am still learning thanks in advance.

I have a Dell Studio 1558. When I originally installed 13.04 on it, I had to modify my /etc/default/grub with the following:  GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor dell_laptop.backlight=0 quiet splash"   Doing that made everything work, the keyboard brightness buttons, the OSD in the top right corner, and the brightness slider in System Settings. However, upon upgrading to 13.10, I once again am unable to adjust the backlight. This is also the case if I use either of the following:    GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor quiet splash"   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"     The backlight is stuck at a single brightness level, at a guess I think it's somewhere around 50%. The OSD still comes up if I push the keyboard buttons, but the bar only goes down one division from 100% and resets back to 100%, if I press decrease again. The slider in 'System Settings' does nothing.    Any help is greatly appreciated!


If I re-write the following code with auto-implemented properties, I understand I have to use a constructor to assign initial values to the variables.  But what happens to the override method? When I remove it, the program does not output anything...  In other words, if I use a constructor and then add auto-implemented properties, I can no longer just use rectangle to simply print out both width and height. Can I?  using System;  namespace Rectangle_Solution {     public class Rectangle     {         private int width  = 5;         private int height = 3;          public int Width         {             get             {                 return width;             }             set             {                 width = value;             }         }          public int Height         {             get             {                  return height;             }             set             {                  height = value;             }         }          public override string ToString()         {             return "width = " + Width + ", height = " + Height;         }          public static void Main( string[] args )         {             Rectangle rectangle = new Rectangle();             Console.WriteLine( "rectangle details - {0}", rectangle );              rectangle.width   = 10;             rectangle.height += 1;             Console.WriteLine( "rectangle details - {0}", rectangle );         }     } }

How do you give a C# auto-property an initial value?  I either use the constructor, or revert to the old syntax.    Using the Constructor:  class Person  {     public Person()     {         Name = "Initial Name";     }     public string Name { get; set; } }   Using normal property syntax  (with an initial value)  private string name = "Initial Name"; public string Name  {     get      {         return name;     }     set     {         name = value;     } }   Is there a better way?


Total beginner, so forgive me if this is working 'as designed'...  When testing a little personal project i noticed than when reloading the page in Firefox (52) the pseudo classes 'reload' in the same state they were in. I.e. If the pseudo is on :after, when hitting the reload button the page refreshes with the element coming up in the :after state.  When i force reload, it loads up ok in the :before state.  Just in case it was an issue with my code i went into a bunch of css switch/toggle generator sites and i get the same behaviour. One particular one (  ) when i set it to "on" and reload, it comes up in the default "off" position, but after a second it sets itself back to "on".  Is that how it's meant to work in FF? Or is it a bug of sorts? It looks like FF saves the state and reloads it as such?  Any tips on how i could get it to always reload in the :before state? I had a good search around for the last hour or so and couldn't find anything relating to it.  Thanks  EDIT: That page i linked. Just realized using Chrome that what i described is how the page is, but on FF if i set it to "off" it reloads as "off" and stays like that, unlike in Chrome.  SECOND EDIT: From that other question pointed out to me, adding autocomplete="off" to the element clears the state and so it reloads in the :before state.  Thanks guys, you are awesome

I'm reloading a web page that has the following code:  Show Image <input id="showimage" name="showimage" type="checkbox" value="1" />   Even though the HTML stays sent to the browser is the same for each reload of the page, the checkbox always takes on the checked value when a reload was performed.  In other words, if the user checks the checkbox and reloads, the checkbox is still checked.  Is there some caching going on here?    Edit: I tried Gordon Bell's solution below and find that this is still happening even after removing the value="1".  Anything else I might be missing?  Show Image  <input id="showimage" name="showimage" type="checkbox" />


I have a UEFI windows 10 machine an I'm trying to dual boot ubuntu. At first I got the error: "grub-efi-amd64-signed failed to install into /target/. Without GRUB boot loader, the installed system will not boot". But I solved that by making a 100MB EFI partition and Ubuntu finished its installation.  Now I don't see a boot menu; I can't use EasyBCD to add Ubuntu to the boot menu; I don't see any options in msconfig menu. And boot-repair did nothing for me!  boot-info:   I don't know if it is relevant, but originally I installed windows in legacy and than converted to UEFI using this

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?


What exactly do eigenvalue and eigenvector indicate?  I mean what is the importance in calculating them. We all know how to calculate them but I do not know the exact importance

What is the importance of eigenvalues/eigenvectors?


I know there is a command to obtain this style of a font but I cannot recall it. Would you please suggest how to obtain this style?

I want to know how can I achieve this effect in LaTeX:    Basically it looks like this: {F}IRST {L}ETTER, where the letters in the braces are a little bigger than the other ones but they all the letters are uppercase.  Any suggestions?


I make this claim in a proof I have written. I will like to prove this for my own sake. How to proceed? I have actually seen this inequality a couple of times before,   Kind regards,

Prove that $\sqrt{n} > \ln n$ for all $n \in \mathbb{N}$.  I need to use this fact for one of the proofs that I am working on. However, I am having trouble proving this. I tried induction but don't really know how to do it. Can someone help me with this?


My requirements are: I need a UPS system which supplies power to a 9 volt modem. UPS should Charge 12v battery (SLA , charging curent 800ma), and it should have overcharge/discharge protection system [optional: it should show the battery capacity with four leds(25% interval)]. I want to achieve this without using ADC. I can make 230V AC to 12v DC converter with step down transformer. Switching from mains to battery can also be achieved with two diodes. But i want to make overcharge/discharge with led indicator which i cant figure out without ADC. Is there any way to achieve this without microcontroller and ADC. Any suggestion would be appreciated. Thanks in advance.  I am thinking about something like this. I have designed this circuit on my own. But i have no idea how to link these two switches to charge level indicator.


I try to compile with lualatex the simple file :  \documentclass{article}  \usepackage{tikz}    \begin{document}           \begin{tikzpicture}            \draw[color=blue]             plot[id=sin,domain=0:6,samples=100] function{sin(x)};         \end{tikzpicture}    \end{document}   The file essai.sin.gnuplot is created but not essai.sin.table. My problem is that the code compiles very well with pdflatex.  Here the beginning of the file.log  This is LuaTeX, Version 1.0.4 (TeX Live 2017) system commands enabled.   Some questions seem similar but I can't find a good answer.

i want to compile several pgfplots pictures with lualatex, since it dynamically allocates memory for compiling (in contrast to pdflatex).  In some plots, like my MWE.tex given below, i want to use a contour plot. This is typically done with gnuplot. To compile a document like this i need to use --shell-escape, such that gnuplot command can be executed while compiling the document.  \documentclass[a4paper]{article}  \usepackage[utf8]{luainputenc} \usepackage{pgfplots} \pgfplotsset{compat=newest} \begin{document} \begin{tikzpicture}   \begin{axis}     \addplot3[contour gnuplot]      {x+y};       \end{axis}   \end{tikzpicture} \end{document}   If i use  pdflatex --shell-escape MWE.tex   everything works fine, and the log says something along the lines  This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016) (preloaded format=pdflatex 2016.6.12)  13 JUN 2016 10:46 entering extended mode  \write18 enabled. .... Package pgfplots notification 'compat/show suggested version=true': document has been generated with the most recent feature set    (\pgfplotsset{compat=1.13}).  \openout3 = `MWE_contourtmp0.dat'.  \openout3 = `MWE_contourtmp0.script'. runsystem(gnuplot "MWE_contourtmp0.script")...executed.   If i use     lualatex --shell-escape MWE.tex i get the following error:  This is LuaTeX, Version 0.95.0 (TeX Live 2016)  (format=lualatex 2016.6.12)  13 JUN 2016 10:52  system commands enabled. ... Package pgfplots notification 'compat/show suggested version=true': document has  been generated with the most recent feature set (\pgfplotsset{compat=1.13}).  Package pgfplots info on input line 10: Using 'lua backend=false' for plot 0 (type 'contour external'): plot handler does not support LUA.  \openout3 = MWE_contourtmp0.dat  \openout3 = MWE_contourtmp0.script gnuplot "MWE_contourtmp0.script"  ! Package pgfplots Error: sorry, plot file{MWE_contourtmp0.table} could not be opened.   The .table file exists and looks identical to the one created by pdflatex, but it says that it cannot be executed.  (I just installed texlive 2016 yesterday, so everything should be up to date.)


Let $ABC$ be a triangle. Let $T$ be its circumcircle and let $I$ be its incenter. Let the internal bisectors of $A,B,C$ meet $T$ at $A',B',C'$ respectively. Let $B'C'$ intersect $AA'$ at $P$ and $AC$ at $Q$. Let $BB'$ intersect $AC$ at $R$. Suppose that the quadrilateral $PIRQ$ is a kite, i.e. $PI=IR$ and $QP=QR$: how to prove that triangle $ABC$ is a equilateral triangle?

Let $\triangle ABC$ be a triangle. Let $Γ$ be its circumcircle, and let $I$ be it’s incenter. Let the internal angle bisectors of $∠A,∠B,∠C$ meet $Γ$ in $A',B',C'$ respectively. Let $B'C'$ intersect $AA'$ at $P$, and $AC$ in $Q$. Let $BB'$ intersect $AC$ in $R$. Suppose the quadrilateral $PIRQ$ is a kite; that is, $IP = IR$ and $QP = QR$. Prove that $\triangle ABC$ is an equilateral triangle.    I can prove upto isosceles triangle. How to prove equilateral?


I have defined a command for absolute value using providecommand. Initially, I simply used \providecommand{\abs}[1]{\lvert#1\rvert}  That was working fine until I needed to take the absolute value of an integral, and the lines did not scale at all. To make the lines scale, I tried \providecommand{\abs}[1]{\left\lvert#1\right\rvert}  This works in the document, but my editor (overleaf) does not like it at all, and has highlighted all subsequent text in red - an error message intermittently displays saying command may only be used in math mode. Is my use OK (and should I therefore ignore the error message - can I override it?) or is there a better way of writing it? Thanks

What is the "best LaTeX practices" for writing absolute value symbols?  Are there any packages which provide good methods?  Some options include |x| and \mid x \mid, but I'm not sure which is best...


Are my suggested edits wrong?     Here are the links of my suggested edits.             These are the list of edits that I have suggested and got the rejection from no human being but a community (machine) moderator.  Please suggest me some way so that my edits are not rejected again.     I would always love to suggest some edits, so there is no reason for me to stop suggesting some correct edits, isn't it?

Why does the Community user sometimes approve or reject edits? How does a machine know if my edit is valid? What does it mean if my edit was rejected by Community?     See also:


I am trying to change screen resolution of Ubuntu 14.04.02 running in VirtualBox. I tried to install  but I'm getting this error -  Reading package lists... Done Building dependency tree  Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies: virtualbox-guest-x11 : Depends: xorg-video-abi-15 Depends: xserver-xorg-core (>= 2:1.14.99.902) E: Unable to correct problems, you have held broken packages.   What should I do to fix this?

I am trying to install Guest Additions in VirtualBox with Windows XP host and Ubuntu 12.04 guest. I followed the above steps:  Devices-> Insert Guest Additions CD Image. After that I locate the folder /media/VBoxAdditions4.3.4_91027/ and run sudo ./VBoxLinuxAdditions.run   I want to be able to create shared folders and adjust the resolution of the screen. I achieved to do the first issue, but I couldn't do the second one. I didn't get any message, however it is not possible to change the resolution of the screen and I cannot switch to fullscreen. What am I doing wrong?  I found in the instal log the following message: unknown version of the X Window System. I've tried the solution of the proposed link but I got the following message:  Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies: virtualbox-guest-x11 : Depends: xorg-video-abi-11                     Depends: xserver-xorg-core (>= 2:1.10.99.901) E: Unable to correct problems, you have held broken packages.   I tried also to install with the command sudo apt-get install virtualbox-guest-dkms but nothing is changing. During the installation of dkms I got the message: Error! Bad return status for module build on kernel 3.13.0-32-generic(i686).


The value of series   $\sum_{n=1}^{\infty}\frac{n}{2^n}$  I try to write some terms,but of no use. Is there any general method to approach such questions.  Thanks

How can I evaluate $$\sum_{n=1}^\infty\frac{2n}{3^{n+1}}$$? I know the answer thanks to , but I'm more concerned with how I can derive that answer. It cites tests to prove that it is convergent, but my class has never learned these before. So I feel that there must be a simpler method.  In general, how can I evaluate $$\sum_{n=0}^\infty (n+1)x^n?$$


At home I have a large nas with a bunch of video files on it (various filetypes).  I'm looking for a way to stream those videos if I need them so I can watch them from any computer that has a internet connection.  It would need username/password protection or at least ip based protection.  Thanks

How do I set up a media server in Linux which streams video over the internet?  Is it easy to do this? I want a server that will actually encode video in real time to allow it to stream over sometimes slow or unreliable networks. Basically, I want a server that works on the internet.  I have a directory with a bunch of video files, and want to make this accessible to myself remotely.  For other situations, I found great and useful software (such as the PS3 media server). I'd like to find something equally as useful for streaming video over the internet.


I have 3 files: file class: i declare the function in header file, inside the class.     template<typename T>     T result(int );   file class implementation .cpp: template<typename T> T List::result(int n){     if (arrt[n]==entero){       int aux=*(int*)arr[n];       return aux;    }else if (arrt[n]==flotante) {       float aux=*(float*)arr[n];       return aux;           }     return 0;  }  i call the function in main.cpp, something like this: cout<<lista.result<int >(0)<<endl;  but i obtain the next issue: /usr/bin/ld: /tmp/cchsdzMH.o: en la función `main':  pruebas.cpp:(.text+0xcc): referencia a `int List::result<int>(int)' sin definir  collect2: error: ld returned 1 exit status  as if it had not been defined in the .cpp implementation file. if I put the implementation of the function in the header file or in the main file it works. the rest of the functions from implementation .cpp works because they dont use a templates. psdta: sorry for my bad english, but it isnt my native language  =)

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I set the following line in cron job under /etc/cron.d/find_old_file  * * * * * root  [[ -d /var/log/ambari-metrics-collector ]] && find  /var/log/ambari-metrics-collector   -type f -mtime +10 -regex '.*\.log.*[0-9]$' -printf '%TY %Tb %Td %TH:%TM %P\n' >> /var/log/find_old_file   this cron should find the logs that older then 10 day ( but only if /var/log/ambari-metrics-collector folder exists )  from some unclear reason we notice that  /var/log/find_old_file not created  and when we test it this line works fine on shell bash but not from cron  we also add 2>&1 in the end of the file but this not work  please advice what is wrong in my cron job ?  more /etc/cron.d/find_old_file  * * * * * root  [[ -d /var/log/ambari-metrics-collector ]] && find  /var/log/ambari-metrics-collector   -type f -mtime +10 -regex '.*\.log.*[0-9]$' -printf '%TY %Tb %Td %TH:%TM %P\n'   >>    /var/log/find_old_file 2>&1   example when we test it on shell bash   [[ -d /var/log/ambari-metrics-collector ]] && find  /var/log/ambari-metrics-collector   -type f -mtime +10 -regex '.*\.log.*[0-9]$' -printf '%TY %Tb %Td %TH:%TM %P\n' 2018 Aug 13 12:54 collector-gc.log-201808130951 2018 Aug 13 04:22 collector-gc.log-201808130403 2018 Aug 01 12:40 gc.log-201808011229 2018 Aug 01 12:40 collector-gc.log-201808011229 2018 Aug 09 15:36 gc.log-201808091332 2018 Aug 09 10:50 gc.log-201808090825 2018 Aug 13 04:02 collector-gc.log-201808130346 2018 Aug 13 16:51 gc.log-201808131358 2018 Aug 01 13:35 gc.log-201808011241 2018 Aug 01 13:35 collector-gc.log-201808011241 2018 Aug 09 15:39 collector-gc.log-201808091332 2018 Aug 02 23:06 gc.log-201808022256   when I put this  * * * * * root echo test  >> /var/log/test   then its works , but not my line as described   so what are happens here?

I want to create a log file for a cron script that has the current hour in the log file name. This is the command I tried to use:  0 * * * * echo hello >> ~/cron-logs/hourly/test`date "+%d"`.log   Unfortunately I get this message when that runs:  /bin/sh: -c: line 0: unexpected EOF while looking for matching ``' /bin/sh: -c: line 1: syntax error: unexpected end of file   I have tried escaping the date part in various ways, but without much luck. Is it possible to make this happen in-line in a crontab file or do I need to create a shell script to do this?


I search for an Ubuntu 20.04 LTS DESKTOP automatic installation ? i boot on a USB KEY with ubuntu 20.04 lts desktop iso on this , i wan't install on a ssd pc with a automatic script (not the live install) I found on internet an good example (& working ) in grub.cfg file : linux /casper/vmlinuz  file=/cdrom/ks.preseed auto=true priority=critical debian-installer/locale=fr_FR keyboard-configuration/layoutcode=fr ubiquity/reboot=true languagechooser/language-name=French countrychooser/shortlist=FR localechooser/supported-locales=fr_FR.UTF-8 boot=casper automatic-ubiquity initrd=/casper/initrd.lz quiet splash noprompt noshell --- but in my case i wan't scripted a script for create partition, create user, crypted disk with luks (cryptsetup) and install package software, i test with this : `linux  /casper/vmlinuz  file=/cdrom/preseed/ks.seed initrd=/install/initrd.gz boot=casper automatic-ubiquity ks=hd:sda1:/ks.cfg quiet splash noprompt noshell ---`  it's ok boot but not load the ks.cfg , i test with hd:sda1:, cdrom:, ... and http no loading, and all no working :( Have you see this problem ? and how can resolve it ? because i'm loss Thanks you very much for a solution !!!

This is the third time I've tried to install Ubuntu Server 14.04.03 64-bit on the same laptop, and each time it caused different problems.  Each time I wrote the same iso image to a USB flash drive by using a different application and OS.   Universal USB Installer (pendrivelinux.com) from Windows WinImage writer from Windows built-in image writer from Linux Mint 17.2    The iso image is the same in all three cases, the USB flash drive is the same, and the laptop is the same. However each time the installation of Ubuntu gave me different installation options. For example, the last time I installed Ubuntu, it didn't show all the packages to choose while installing (Basic Ubuntu server, etc.).


Hello I have got a little "problem" ...  I just seems weird to me that when you check the code below that it says false if I type same number twice in the dialog fields.  I am kinda new to Java but not to programming itself and it does not make any sense.   Thanks in advance      import javax.swing.*;   public class Praeinkrement {      public static void main(String[] args) {          String a = JOptionPane.showInputDialog("Zahl a");         String b = JOptionPane.showInputDialog("Zahl b");           Double c = Double.parseDouble(a);         Double d = Double.parseDouble(b);          boolean e, f;         e = (c == d);         f = (c < d);          JOptionPane.showMessageDialog(null, e + "\n" + f);      } }

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 have a GeoServer running on my localhost also I have a react app which consumes a WFS service to get a GeoJSON data to render as a layer over the map.  These are my dependencies on my package.json  "axios": "^0.19.0", "leaflet": "^1.5.1", "react": "^16.8.6", "react-dom": "^16.8.6", "react-leaflet": "^2.4.0", "react-scripts": "3.0.1"   And this is my HomePage.js in my react app  // @packages import React, { PureComponent } from 'react'; import axios from 'axios';  import {     GeoJSON,     Map,     TileLayer } from 'react-leaflet';  // @constants const GEOSERVER = 'http://localhost:8080/geoserver/wfs';  const REQUEST_PARAMS = {     outputFormat: 'application/json',     maxFeatures: 250,     request: 'GetFeature',     service: 'WFS',     typeName: 'gaia:mining_titles',     version: '1.0.0' };  class HomePage extends PureComponent {     constructor() {         super();         this.map = null;         this.state = {             center: [6.217679, -75.570648],             data: null,             zoom: 8         };         this.handleOnMapMounted = this.handleOnMapMounted.bind(this);     }      componentDidMount() {         axios.get(GEOSERVER, { params: REQUEST_PARAMS })             .then(({ data }) => this.setState({ data }))             .catch(error => Promise.reject(error));     }      handleOnMapMounted(evt) {         this.map = evt ? evt.leafletElement : null;     }      render() {         const {             center,             data,             zoom         } = this.state;          return(             <Map                 center={center}                 id="home-page-map"                 ref={this.handleOnMapMounted}                 zoom={zoom}             >                 <TileLayer                     url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"                     attribution="&copy; OpenStreetMap contributors"                 />                 <GeoJSON data={data} />             </Map>         )     } }  export default HomePage;   When the componentDidMount is called the data is set on the state but doesn't render anything and doesn't show errors it just nothing happens.  I already enabled the CORS configuration on my web.xml from my GeoServer  EDIT:  This is the response from the GeoServer  {"type":"FeatureCollection","features":[{"type":"Feature","id":"mining_titles.4133","geometry":{"type":"MultiPolygon","coordinates":[[[[689969.6239,566781.7359],[689969.6246,566381.7341],[690169.6234,566381.7345],[690169.6237,566231.7353],[689873.623,566283.7334],[689757.6244,566421.7352],[689757.6241,566621.734],[689835.6237,566781.7357],[689969.6239,566781.7359]]]]},"geometry_name":"geom","properties":{"id":4133,"objectid":1,"oid_":9918,"id_1":4133,"codigo_exp":"HCS-152","codigo_rmn":"HCS-152","codigo_ant":"HCS-152","fecha_cont":"2006-06-29Z","fecha_insc":"2007-05-17Z","grupo_trab":"PAR PASTO","estado_exp":"TITULO VIGENTE-EN EJECUCION","modalidade":"CONTRATO DE CONCESION (L 685)","minerales":"MATERIALES DE CONSTRUCCION","titulares":"(69021277) CLAUDIA CECILIA BETANCOURT YEPES\\ (12972275) GERMAN NAZARENO BETANCOURT PANTOJA","municipios":"ORITO-PUTUMAYO","fecha_term":"2037-05-16Z","shape_leng":1742.81141444,"shape_area":118628.3028,"grupo":null}}],"totalFeatures":8861,"numberMatched":8861,"numberReturned":1,"timeStamp":"2019-07-16T16:39:34.595Z","crs":{"type":"name","properties":{"name":"urn:ogc:def:crs:EPSG::3116"}}}

I am trying to get a GeoJSON with projected coordinates to show in Leaflet.  I have no problems loading GeoJSON with lat/lng (EPSG:4326). Here is a  where I load the GeoJSON with unprojected lat/lng.  I am using the Leaflet 1.0.0-beta.2 (954e83d) in the fiddle but I am happy to use another version.  I am aware of the coordsToLatLng method of L.geoJson but no idea how to make this work.  This is the GeoJSON with the projected (EPSG:3857) coordinates.  {     "type": "FeatureCollection",     "crs": {         "type": "name",         "properties": {             "name": "urn:ogc:def:crs:EPSG::3857"         }     },     "features": [{         "type": "Feature",         "properties": {          },         "geometry": {             "type": "Polygon",             "coordinates": [[             [-625570.6, 6465993.0],             [-305006.9, 6696510.8],             [-546330.2, 6768547.6],             [-445478.6, 7053093.0],             [-279794.0, 7056694.8],             [-359034.5, 7337638.4],             [-211359.0, 7485313.8],             [62380.8,   6955843.3],             [220861.7,  6909019.4],             [91195.5,   6700112.6],             [213658.1,  6682103.4],             [-625570.6, 6465993.0]]]         }     }] }     Notes: I am new to Leaflet. I come from a GIS background. I have a very good understanding of projections and transformations. I have a very good understanding of OpenLayers3. I use OL3 to do things such as this on a daily basis. The data in this post is obviously just an example. I am trying to learn Leaflet in order to compare the performance with OL3. I know how to use QGIS and can unproject the data manually but this is not the point of this post.  This is not a repost. I have checked every bit of information on coordsToLatLng but didn't find any good documentation and nothing like a working example. Certainly no fiddle.  Just saying this as I have read a lot of Leaflet posts on gis.stackexchange with half-a-code. And a lot of answers which suggest to change the data. I know that Leaflet is not a GIS system and the makers are not from a GIS background. In the last hour I have just read a lot of rubbish about Leaflet using EPSG:3857 as default SRS and WGS84 being an SRS.


I have Ubuntu 12.04 desktop running on my box. I enabled 'auto login' for my account (only account on system) and it has worked just fine before. I usually have it as a headless server.  I needed to use the desktop for something but it won't let me login. I can SSH to it, use the Transmission Web GUI, webserver and everything else, except at the login screen.  When I enter the password, it acts like it's logging in but then comes right back to the login screen.    I tried creating another user and using the auto login for that user and it works fine.    Any suggestions?

My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M


Note: I'm aware that there is also a site "English learning". I thought a while about whether it would be a better fit there, and eyes quickly glancing over some passages of this text might think that. But I have doubts. I know how to use that aspect of the language, I don't need to learn it. I rather want to dive a little deeper, perhaps, and have a suspicion that the average native speaker who might easily help on the learners' site might not precisely know about this subject. It might rather be "language enthusiasts" thinking about this kind of topic, and apparently, that's what this site is for?  So - What do I mean, by sentences like "The window does not open."?  I mean sentences that seem to be indicating that the noun was somehow active, even though it is factually a passive object that something needs to be done to by someone or something else.  Well, at least that's what I, native speaker of a related language that does not have this (German), think when seeing/hearing something like that.  Another example: Think of a text file which contains program code of a programming language. The code has a syntax error somewhere. You try to run the program code, but the interpreter indicates the error. A native speaker might say: "The source file did not parse".  This seems extremely odd to me. I can only speak for myself, but I would guess the same for many other native German speakers. (maybe less so for the youngest generations who started to learn English at earlier ages) We would never say this. Rather, it would be: "The window cannot be opened" or "The window is not openable" and "The source file could not be parsed" or "The intepreter failed to parse the source file", clearly indicating the factually passive object as a thing that something is done to (or not). Wheras "the window does (not) open" makes it seem as though the window was something that, potentially, does things by itself. (let's restrict this to classical windows, not windows in maybe Elon Musk's home ;)) Even more obvious is the source file, which most certainly does not do things by itself, like parse.  It's as though someone said, to indicate the location of certain information within a given book: "The information finds on page 42" instead of "The information can be found on page 42". If I'm not mistaken, this would seem weird to a native speaker of English, too; i.e. it is not common to say / wrong.  What do native English speakers actually think when hearing or uttering such a sentence? Does it feel to you like those objects were active things? Or is there maybe some example that would clearly show that these sentences do not indicate activity on the part of the objects / some way to show me I fell into a trap of thought by the language conventions / expectations I'm used to?

You're standing in front of a ticket vending machine and it says "The ticket is printing". Is that correct or should it be "The ticket is being printed"?  EDIT:  If both are correct, which one should be preferred or is more common?


Let $f : X \longrightarrow Y$ be continuous, and let $A \subseteq X$. Show that $f(\overline A) \subseteq \overline{f(A)}$.   My attempt  Let $y \in f(\overline A)$. Then there exists $x \in \overline A$ such that $f(x) = y$. Now let us take an open neighbourhood $V$ of $y$ in $Y$ arbitrarily. If we can show that $V \cap f(A) \neq \emptyset$ then our purpose will be served.  Now since $f(x) = y \in V$, we have $x \in f^{-1} (V)$. Since $x \in \overline A$ and $f^{-1} (V)$ is open in $X$ (since $f$ is continuous), we have that $f^{-1} (V) \cap A \neq \emptyset$.  Let $z \in f^{-1} (V) \cap A$. Then $f(z) \in V \cap f(A)$, which proves that $V \cap f(A) \neq \emptyset$ and we are done.  Is my reasoning correct at all? Please verify it.

It'd be great if someone checked the proof I did for the following problem:  $f:X\longrightarrow Y$,   $f(\overline{A})\subseteq \overline{f(A)},\forall A\subseteq X \Leftrightarrow f$ continuous  proof:  Suppose $f(\overline{A})\subseteq \overline{f(A)}$ for any $A\subseteq X$ .  Let $C\subseteq Y$ be closed and define $A=f^{-1}(C)$.  $f(\overline{A})\subseteq \overline{f(A)}\subseteq\overline{C}=C$, therefore $\overline{A}\subseteq f^{-1}(C)=A$,  so $A$ is closed.  *Conversely, suppose $f$ is continuous.    Let $p\in\overline{A}$ and let $V$ be an open neighborhood of $f(p)$. Since $f$ is continuous,  $f^{-1}(V)$ is open. On the other hand $p\in f^{-1}(V)$, but since $p\in\overline{A}$ we have that $f^{-1}(V)$ contains points of  $A$. Therefore $V$ contains points of $f(A)$. Since $V$ is an arbitrary neighborhood of $f(p)$, we have $f(p)\in \overline{f(A)}$. So finally, $f(\overline{A})\subseteq\overline{f(A)}$.  Thank you very much!


Say that you have a die with n faces, and you need to throw the die until the sum of your results exceeds a given threshold. What is the average number of throws needed? I think that to compute that average, you need the probability distribution of exceeding the threshold for a given number of throws, but I can't seem to find any "classical" distribution fitting that description...

I was recently commenting on game mechanics, when I realized that I actually underestimated this particular part.  Given an unbalanced die (in this case, some of the sides are 0), what is the expect number of rolls to reach a total sum of N.  As an example. What is the expected number of dice rolls with a die having sides [0,0,0,1,2,6] to reach the sum 24.  I can do this for a balanced die, because that is uniform distribution, so the expected number of rolls is ceil(N/((1+2+3+4+5+6)/6)) so in this example it would be ceil(24/3.5)=7 rolls.


Sorry for bad english.   The animate function of jQuery work fine at line 2. But at line 3 doesn't work... why?     $('.opac').hover(function(){       $('img', this).animate({opacity: '0.6'}, 500);     $('p', this).animate({background: 'orange'}, 500);      });   The HTML is this:

text here...

   Thanks! ps: the developer tool doesn't give any error...

I am trying to animate a change in backgroundColor using jQuery on mouseover.  I have checked some example and I seem to have it right, it works with other properties like fontSize, but with backgroundColor I get and "Invalid Property" js error. The element I am working with is a div.  $(".usercontent").mouseover(function() {     $(this).animate({ backgroundColor: "olive" }, "slow"); });   Any ideas?


I am writing an essay about overcoming a hard time and staying motivated through it. I want an idiom to be the title. What should it be? It could also be about bringing down something bad, like: "The Abolition of Adversity"

Life is full of adversity, and people facing challenging life circumstances have to find a way to cope. I'm interested in single words, phrases, or idioms that capture coping strategies. For example:     Jane's job was absurdly repetitive and oppressive, but for her family, she tried to make the best of a bad situation.   Are there good alternatives to the coping strategy of making the best of bad situation?   Clarification: I am looking for alternatives, especially idioms, that don't involve words like good and bad.


Let a, b and c be such that $ a+b+c = 0 $ and  $ l^2 = \frac{a^2}{2a^2+bc} + \frac{b^2}{2b^2+ac} + \frac{c^2}{2c^2+ba} $  The what is the value of l   My approach : I could just put in the adequate values of a,b and c and check what comes out to be the value of $l$.   However I am looking for a more general approach to solve the following problem , I thought of using Lagrangian to solve , but that process looks to be too lengthy.   Any insight on what approach to follow would be welcome.

I'm stuck at this algebra problem, it seems to me that's what's provided doesn't even at all.  Provided:  $$a+b+c=0$$  Find the value of:  $$\frac{a^2}{2a^2+bc}+\frac{b^2}{2b^2+ac}+\frac{c^2}{2c^2+ab}$$  Like I'm not sure where to start, and the provided clue doesn't even make sense.  There's no way I can think of to factor this big polynomial into a form like $a\times p+b\times q+c\times r=s$ where $p,q,r,s\in\mathbb{Z}$.  Thanks!


I am currently studying discrete math and I am unsure of how to format this proof in such a way to get my point across. If anyone could write it out for me that would be very appreciated!

If $x,y$ are positive integers and $x\geq1$ and $y\leq1$, then $x+y\geq x\cdot y+1$  Don't have a direction, much appreciated.


Help me to compute the following limit   $$  \lim_{a\to \infty}\frac1a\int_1^a a^{\frac1x} dx$$     I failed to apply the mean value theorem. And this the feature i had in mind when I saw this first   Any Hint?

On this year's  there was this problem:  Compute $$ \lim_{A\to\infty} \frac{1}{A} \int\limits_1^A \! A^{\frac{1}{x}} \, \mathrm{d}x. $$  In addition to the two official solutions, I am curious as to if there exist other solutions.   I heard that someone wrote that this is actually a probability density function (just for this one line, that person got 6 out of 10 points), so it would be great to see an answer involving this claim.  Also, I thought of turning this integral (using substitutions) to something I can evaluate using the Gamma function. Could someone hint a substitution which could lead to that?  EDIT: The official solutions can be found , Problem 7.


I want to find the index of values that contain a keyword in an array.  For example:  A = ['a1','b1','a324'] keyword = 'a'   I want to get [0,2], which is the index of a1, a324  I tried this list(filter(lambda x:'a' in x, A)) But get ['a1','a324'] rather than the index.

Given a list ["foo", "bar", "baz"] and an item in the list "bar", how do I get its index (1) in Python?


I'm trying to detect when a player is looking at another player to re-create Dream's 'Speedrunner v Assassin' video with GeorgeNotFound, in which if George looks at Dream, Dream becomes frozen. I would do this in Java but my friend only has Bedrock. Anyone know how to do this with command blocks?

So, I'm trying to make a gravity gun type thing in Minecraft. What I have so far is as follows. A command block which is always powered and has the command: /enchant @p sharpness 2  (it detects when you hold a sword). And a command block which would be the output that has execute @p ~ ~ ~ tp @e[type=villager] ^ ^ ^5 facing ^ ^ ^  Any help? I just need a command that detects if you look at a villager.


After upgrading from ubuntu 18.04 to 20.04 ubuntu software can't show any apps.

This is the error I get when I open the software center. I've tried rebooting and running sudo apt-get update but I see no improvement. It worked earlier but I don't know what went wrong since then. I'm using Ubuntu 16.04 final release on a Dell Inspiron 15R. Any advice will be appreciated. Thanks in advance.  EDIT: The problem magically solved itself without me doing anything special (or maybe inadvertently doing something, I don't know). So I'd still like to get to the root of this.


Let $(X, d)$ be a metric space and $Y\subseteq X$.   Is $\partial Y$ always a closed set?

A point $p$ in a metric space $X$ is a boundary point of the set $A$, if any neighbourhood of $p$ has points of both $A$ and $X-A$.Prove that the set of all boundary points of $A$ is closed.  My attempt: By definition of an open set this means that for every $x$ in the boundary there is an open ball centred at $x$ contained in the boundary. An open ball is a neighbourhood of $x$, which implies it contains points of $A$ and $X - A$, which in turn implies there are points in both $A$ and $X - A$ that are in the boundary of $A$.  If $A$ is open, then pick any such point in $A$ that is also in the boundary. This point cannot be in $X - A$ by definition of set subtraction. Further, because $A$ is open there exists an open ball centred around this point contained in $A$. Again, an open ball is a neighbourhood, which means a neighborhood of this point does not contain points of $X - A$, implying it cannot be in the boundary, a contradiction. If A is closed then $X - A$ is open and a symmetric argument holds. Hence the boundary is closed.  Is my work correct?


After downloading the software from epson & running the ./install.sh file as instructed, I get the following error: Err:19 http://www.getdeb.net/ubuntu xenial-getdeb/apps amd64 Packages   403  Forbidden Ign:20 http://www.getdeb.net/ubuntu xenial-getdeb/apps i386 Packages Reading package lists... Done W: The repository 'http://archive.getdeb.net/ubuntu xenial-getdeb Release' does not have a Release file. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use. N: See apt-secure(8) manpage for repository creation and user configuration details. E: Failed to fetch http://www.getdeb.net/ubuntu/dists/xenial-getdeb/apps/binary-amd64/Packages  403  Forbidden E: Some index files failed to download. They have been ignored, or old ones used  Any help with this problem would be much appreciated.

When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?


I have to do many math exercises for young children. A drawing helps them a lot. But I can not paste images because it consumes a lot of memory of the  that I use so I have to put the pictures in code. Do you know any program that can help me draw?

I found  to be a useful tool to help generate code for graphs. I suppose there must be other tools to help draw diagrams such as Sets/Venn Diagrams or Electrical Circuits (Logic Gates). Which ones would you suggest?


I have been rejected for visas 5 times in 4 countries. 3 of those were Schengen countries. Now, I want to study in the UK. Will it be a big issue?. Will the UK home office know everything about my rejection?

When certain nationalities of people want to travel in the Schengen zone, they are required to apply for a Schengen visa. This is a straight-forward process for most, but when an applicant has had problems with removals or refusals they may be reluctant to apply because they want to avoid the complexities of serial visa refusals. This reluctance may lead some into wondering how their history can be expunged, and this line of thought inevitably leads to the idea of getting their passport replaced with a new one.  This sounds like a great formula for people who have had prior refusals or removals.  In essence they can become 'reincarnated' as a first-time traveller and hence avoid the unpleasantness of revealing their prior interactions with the Schengen authorities.  The relevant parts of the application form are shown here...    Nothing asks about a prior removal or refusal, and the applicant is left with simple denials for 3 questions in order to present themselves as a first-time traveller.  Assuming the person is happy to set aside the moral issues associated with denying their history, are there any holes to this strategy?  This question is scoped to Schengen visa applications so that it will not be unmanageably broad, but answers from other regimes (particularly the affluent Commonwealth and the USA) are acceptable as long as the main points are relatively consistent with Schengen.


I have an example in which $Y_t$ is the Ito diffusion with generator $A(f )(x) = αxf '(x) + 2x^2f ''(x).$  Assume $Y_0 = y ∈ R^+.$  I would like to find $Y_t$ and from that would like to find $E [Y_t ]$ and $Var [Y_t ]$.  Can someone please walk me through this example?

Someone please help me with this:  I have that $X_t$ is the Ito diffusion with genertator $A(f)(x)=\alpha xf'(x)+f''(x).$   Then, if $X_0=x \in \mathbb{R}^+$, how do I find $X_t$?


I want to start module theory from the very beginning. I have a little bit of idea about what module is but I haven't really solved a handful of problems. Could someone please suggest me a good treatise on this subject? I badly  need it.

I am very interested in studying modules, which I have studied algebra, is basic theory of groups and rings, of Hungerford and Dummit. I was reading the Dummit the module, but I still struggled a bit in the section and the tensor product of exact sequences, as in the book of Atiyah. They know a simple book to begin with?


I unwrapped a simple plane and applied the following 80x80 pixel picture:    Yes, it's quite small. The problem is, the result is all blurry, like so:    How do I make it accurate to the pixel?

I have a problem. I am going to make a minecraft animation in blender. But when I put a minecraft texture on a 3d cube that is 16x16x16 it is very low resolution is there a way to get the texture in a better resolution or is there a way to make blender make the texture better?  I hope you have an answer. Thanks in advance


Is there any way that Stack Overflow can add a Github login to their site?

I've seen sign in methods using  as an authentication provider, for example : (AWS Cloud9)        Is it possible to authenticate into Stack Exchange using this method? At the moment there's other methods such as OpenID, Google, Yahoo and Facebook, but it would be interesting to also have the GitHub authentication.


I've been riding a 2017 Giant AnyRoad CoMax for about 2.5 months now and today I checked the chain wear with a Park Tool Chain Wear Indicator:    The wear is between 0.5 and .075.  I plan on replacing the chain when it gets to .75, which is probably about a month away, perhaps slightly less.  So, its time to look at ordering a replacement chain.  Upon going to the web page for the bike:    The specification for the chain is "KMC X11", seems simple enough, but upon searching Amazon for "KMC X11":    or the KMC page for 11 speed chains:    I find I'm overwhelmed with the options.  They include:  -"DLC" (Diamond Like Coating)  -TI Nitride  -Silver  -"ECO PROTEQ"  -Nickel  Weights seem to include L (light), SL (super light), and XL (extra light).  The most popular choice on Amazon seems to be the "KMC X11.93 Nickel":    which is also the least expensive by far at $24.  All the others listed above are at least 2x as much, some 3x - 4x as much.  I ride my bike 90+% for commuting, so saving large amounts of weight (ex. carbon vs aluminum frame) is significant, but when getting down to counting grams it doesn't much matter for my riding purposes.  Of course the manufacturer's description of the more expensive chains (i.e. all the options other than Nickel) imply that they are worth the extra cost and provide all-worldly benefits, but I'm skeptical I would notice a difference.  So here are my questions:  -What are the advantages of Silver or TI Nitride over Nickel?  -Is there such a thing as "Diamond Like Coating" or is this just manufacturer hype?  -Would I notice the slight weight difference with the L vs SL vs XL, or is this something that would only matter to a competitive cyclist trying to shave a few seconds off a run?  -Other than the coating, are the more expensive chains actually built more robustly?  Of course the KMC website claims the more expensive chains are more resistant to stretching, but is the difference enough to be significant?  -My inclination is to go with the $24 Nickel chain, is there a compelling reason that the 2x-4x more expense chains would be better for a non-competitive cyclist?  Edit: somebody linked a semi-related post that mentioned Nickel plating, thanks for the suggestion, but that post did not address by other inquiries

Bicycle chains with higher model numbers (and slightly higher prices) are often nickel-plated or half-nickel-plated. What are the benefits of nickel-plated chains over non-nickel-plated chains?  How durable is the plating--does it wear off, or do its benefits last for the life of the chain?


Since I couldn't find no similar question already asked here, I launch this question (I'm sorry if what I'm going to ask has been already posted. I would like to know if so in order to delete this post).  My question is regarding the well-known characterization of the closure of a set in metric spaces,     Let $(X,d)$ be a metric space and $A\subset X$. The following are equivalent:         $a\in \overline{A}$.   There exists a sequence $\{a_n\}\subset A$ converging to $a$.      (such result I think is the same as saying that closedness is equivalent to sequential closedness in metric spaces).  Now, what I'm concerned about is the relation that this result has with the Axiom of Choice. Specifically, I'm concerned about its proof and the usage of the Axiom of Countable Choice.  The proof that I know for 1. $\Rightarrow$ 2. goes as following,     Let $a\in \overline{A}$. Then $B(a,\frac{1}{n})\cap A\neq \varnothing$ for every $n\in \mathbb{N}$ (where $B(x,r)$ is the open ball of center $x\in X$ and radius $r>0$ for the metric $d$). Now, for each $n\in \mathbb{N}$, pick some $a_n \in B(a,\frac{1}{n})\cap A$. It is now easy to show that $\{a_n\}\subset A$ converges to $a$.   I don't know about foundations nor set theory, but I think that what is being used in the choice of the $a_n$ is the Axiom of Countable Choice (on the other hand, the 2. $\Rightarrow$ 1. part present no problematic whatsoever regarding AC and it is a general result valid for arbitrary topological spaces).  My questions are:   Can 1. $\Rightarrow$ 2. be proven without ACC? If not, could it even be that such statement is equivalent to ACC? (1. $\Rightarrow$ 2.) $\iff$ ACC.   Any kind of help will be appreciated.

On  it is mentioned that "...  in order to prove that every accumulation point $x$ of a set $S\subseteq \mathbf R$ is the limit of some sequence of elements of $S\setminus \{x\}$, one uses (a weak form of) the axiom of countable choice. When formulated for accumulation points of arbitrary metric spaces, the statement becomes equivalent to $AC_\omega$. ..."  I have Herrlich's paper "Choice principles in elementary topology and analysis" where in theorem 2.4. it is stated that these are indeed equivalent. Then I looked up the reference he quotes, [4], which are Bentley H.L., Herrlich H., Countable choice and pseudometric spaces which does not contain the proof and  does also not contain the proof, hence my question:   Where can I see a proof of      "if $S$ is a set in a metric space $X$ with accumulation point $s$   then there exists a sequence $s_n$ in $S$ converging to $s$"   $\implies$ $AC_\omega$   ? (the other implication is clear to me). Thanks.


I have a program in which I use a PrintStream object to write to a file. Is there a way to use something like a String Buffer or similar as the OutputStream for the object instead, so that I can use print to append to the String ? I later want to be able to retrieve this String (obviously)  (ps. i wanna do this for testing purposes in my program)  Some info:  PrintStream ps = new PrintStream(myOutputStream); ... ps.print(...); ... ps.close();   I want to replace myOutputStream with some kind of String buffer which I can retrieve later and read.  As far as I know, in C++ we can do this as  stringstream ss; ss << ...   How to do this in Java ?

What's the best way to pipe the output from an java.io.OutputStream to a String in Java?  Say I have the method:    writeToStream(Object o, OutputStream out)   Which writes certain data from the object to the given stream. However, I want to get this output into a String as easily as possible.  I'm considering writing a class like this (untested):  class StringOutputStream extends OutputStream {    StringBuilder mBuf;    public void write(int byte) throws IOException {     mBuf.append((char) byte);   }    public String getString() {     return mBuf.toString();   } }   But is there a better way? I only want to run a test!


Could you help me, please? In our country EL students have got special copy-books where they write new English words down (not in alphabetical order). How is it correct to call such a copy-book in English: a dictionary or a vocabulary?

What exactly is the difference? Around the Web, I'm finding contradictory information and sometimes circular references.  Some say the lexicon is inherent to a language (objective) while a vocabulary is only relative to a (group of) person(s) (subjective). Wikipedia says the lexicon is the vocabulary of a language.  Dictionary should be an easy one, it's a mapping, either between languages or between words and word sense definitions. But some definitions of vocabulary seem to be equivalent to the latter.  Are there any clear formal definitions?


I have tried many tutorials in the internet to solve this problem but still can't get wireless connection in my computer.

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.


Why people can use both <? and <?php? Why are they different ? What are the use cases for both (if there is any) ?

Here's the information :     There are four different pairs of   opening and closing tags which can be   used in PHP. Two of those, <?php ?>   and <script language="php"> </script>,   are always available. The other two   are short tags and ASP style tags, and   can be turned on and off from the   php.ini configuration file. As such,   while some people find short tags and   ASP style tags convenient, they are   less portable, and generally not   recommended.   In my experience most servers do have short tags enabled. Typing  <?=   is far more convenient than typing  <?php echo    The programmers convenience is an important factor, so why are they not recommended?


I am using Resharper 5.1 code analysis many a times i get a comment from resharper as    "Event unsubscription via anonymous delegate"    #Part of Code    if (((bool)e.NewValue)) {     listView.PreviewTextInput += (o,args) =>         listView_PreviewTextInput(o,args,listView); } else {     listView.PreviewTextInput -= (o, args) =>          listView_PreviewTextInput(o, args, listView); }   How could i correct or  optimze this thing

Is it possible to unsubscribe an anonymous method from an event?  If I subscribe to an event like this:  void MyMethod() {     Console.WriteLine("I did it!"); }  MyEvent += MyMethod;   I can un-subscribe like this:  MyEvent -= MyMethod;   But if I subscribe using an anonymous method:  MyEvent += delegate(){Console.WriteLine("I did it!");};   is it possible to unsubscribe this anonymous method?  If so, how?


I'm using the new WordPress 3.8 and I've noticed that when I leave the admin page open in a tab, and return later, I'm getting a random thing happening with the dashicon fonts used for the menu icons.  They all turn to squares, rather than the appropriate dashicon. Its as if the connection to the server that hosts the webfonts has been temporarily lost.  Interestingly, just moving my mouse over the sidebar area makes the squares transform into their appropriate dashicon font symbol.  Has anyone else experienced this?

I've started using the dashicon fonts in my theme options page for WP 3.8+ users. To take care of users on < 3.8, I've added the dashicon fonts to my theme folder and also an entry at the top of my custom admin stylesheet:  @font-face {     font-family: 'dashicons';     src: url('fonts/dashicons.eot'); }  @font-face {         font-family: 'dashicons';         src: url(data:application/x-font-woff;charset=utf-8;base64,xxx) format('woff'),         url('fonts/dashicons.ttf') format('truetype'),         url('fonts/dashicons.svg#dashicons') format('svg');     font-weight: normal;     font-style: normal; }   (I've left out the base64 encode for brevity)  This works great, however, I'm getting a bit of strange behavior with the fonts. When I leave the admin open in a tab and go away for a bit, then come back, every once in a while, the webfonts have turned to squares, as if the font is missing.  This does not happen every time. It appears to be somewhat random.  In those cases, simply doing a mouseover the page usually returns the webfonts to their proper symbols.  The screenshots below show the issue. The first screenshot is what I see when the problem occurs. The second screenshot is what I'm expecting to see when things go well.   Notice in the first shot, how the wordpress labels themselves have gone to a default serif font.


I know that conservation of momentum is caused by invariance (symmetry) of the laws of mechanics to translation - this is an example of . However, I'm looking for an explanation, using only the terminology of Newtonian mechanics (force, position and its derivatives, etc.) and not Lagrangian or Hamiltonian mechanics, why this specific example of Noether's theorem hold - without understanding the theorem as a whole. Think of trying to explain why momentum has to be conserved to someone learning Newtonian mechanics for the first time. A bit of calculus would be fine, but terms like Lagrangian, Noether's theorem, are not. The Wikipedia article  gives a different justification for conservation of momentum - Newton's third law. But this appears to be a different justification of the conservation of momentum - it's not based on translation invariance. Or, maybe Newton's third law could be proved from translation invariance and both explanations are somehow equivalent?

It is well known from Noether's Theorem how from continuous symmetries in the Lagrangian one gets a conserved charge which corresponds to linear momentum, angular momentum for translational and rotational symmetries and others.  Is there any elementary argument for why linear or angular momentum specifically (and not other conserved quantities) are conserved which does not require knowledge of Lagrangians? By elementary I mean, "if this is not so, then this unreasonable thing occurs".   Of course, we can say "if we want our laws to be the same at a different point in space then linear conservation must be conserved", but can we derive mathematically the expression for the conserved quantity without using the Lagrangian?  I want to explain to a friend why they are conserved but he doesn't have the background to understand the Lagrangian formalism.


A webpage X had a text : old-text and it got indexed with this keyword old-text Now that content is removed from the page X but page is still active with different content. Still if user is searching for old-text in google search, page X with which it indexed earlier comes up while on page X old-text is not available at all. Following are the questions:  Is there any way to remove this index using some tool like webconsole Does google keep keyword level index permanent If it auto clears this irrelevant index automatically and then after how much time ?  This is creating severe problem for us where this old-text is sensitive information that needs immediate removal from google search.

Is there any way to remove a website from appearing in Google search results under an unwanted keyword?   About a year ago, I added a featured project to a company website. This page included the client's name - she requested we keep the project anonymous so we removed any mention of her name and any identifying details.  Today - when you Google her name, our website homepage comes up regardless of her name not being on our website. I've even checked Google's cached page.  I'm stumped as to why our site, without any matching keywords would appear above other relevant results.


claim:  if$$ \sum_{n=1}^{\infty } a_{2n} \  and \sum_{n=1}^{\infty } a_{2n-1} $$ both converge than  $$ \sum_{n=1}^{\infty } a_{n}  $$ converge. I managed to prove that this claim is true if $a_n \ge0$ but, what about general series ?  I got the same issue with this claim :  $$ \sum_{n=1}^{\infty } |a_{n}| converge  $$ than  $$ \sum_{n=1}^{\infty } a_{n}\ ^ 2  $$ converge. again ,  managed to prove that this claim is true if $a_n \ge0$.  Thanks for helping.

I want to prove that if $\sum_{n=1}^\infty a_{2n}$ and $\sum_{n=1}^\infty a_{2n-1}$ converge then $\sum_{n=1}^\infty a_n$ converges as well.  Can I prove this like this: $\sum_{n=1}^\infty a_{2n-1}+\sum_{n=1}^\infty a_{2n}=\sum_{n=1}^\infty a_{2n-1}+a_{2n}=\sum_{n=1}^\infty a_n$  The first equality can be done because they both converge, but I'm not sure about the second one.


I have an account in stackoverflow.com, today I tried to join a chat room for some technical discussion and help. But I am not able to login to it. chat.stackoverflow.com is throwing "Something bad happened error" and If I directly click the link to join the chat room. It is showing that I need to be login to chat, but I am already logged in. I don't unerstand why it is happening to my account. Any solution for this?

I just recreated my MSE account after having deleted it a few years ago. Now, I'm trying to log in to Meta Stack Exchange Chat, and whenever I try to do so, it just fails silently and I'm still logged out.  Additionally, in the same browser session that I'm supposedly logged out, I get a server error when accessing the chat homepage or the chat profile page of any user. I don't get any errors when trying to access any of these pages in a private session. I also was able to sign in to Stack Exchange Chat and Stack Overflow Chat without problems, since my accounts on SO and my parent site for SE chat haven't been deleted.  I think it might be because it's trying to sign me in to my old chat profile, which was not deleted, but that is associated to my old, deleted site account, which clash and thus cause it to fail.


Below mentioned is the sample code under discussion:  DECLARE @FROMDATE AS DATETIME DECLARE @TODATE AS DATETIME DECLARE @DAYS AS VARCHAR(100)  SET @FROMDATE = CONVERT(DATETIME, '2017-09-03') SET @TODATE = CONVERT(DATETIME, '2017-09-06')  SET @DAYS = '''SUNDAY'',''MONDAY'',''TUESDAY'',''WEDNESDAY'',''FRIDAY'',''SATURDAY'''  PRINT @DAYS  --(O/P - 'SUNDAY','MONDAY','TUESDAY','WEDNESDAY','FRIDAY','SATURDAY')  SELECT      UPPER(DATENAME(dw, CONVERT(DATETIME, CONVERT(VARCHAR(10), APPDATE, 112)))),      *  FROM      SQLTABLE WHERE      UPPER(DATENAME(dw, CONVERT(DATETIME, CONVERT(VARCHAR(10), APPDATE, 112)))) IN (@DAYS)   If I pass values manually as below I get output:  UPPER(DATENAME(dw, CONVERT(DATETIME, CONVERT(VARCHAR(10), APPDATE, 112))))  IN ('SUNDAY','MONDAY','TUESDAY','WEDNESDAY','FRIDAY','SATURDAY')   If I pass values using variable having the same values as shown in the O/P of PRINT @DAYS the result is blank:  UPPER(DATENAME(dw, CONVERT(DATETIME, CONVERT(VARCHAR(10), APPDATE, 112))))  IN (@DAYS)   Assuming that in actual scenario I am generating the values under @DAYS variable dynamically or passing it through code to the query / stored procedure below is my question :  Is it not allowed in SQL or am I doing it wrongly?

How do I parameterize a query containing an IN clause with a variable number of arguments, like this one?  SELECT * FROM Tags  WHERE Name IN ('ruby','rails','scruffy','rubyonrails') ORDER BY Count DESC   In this query, the number of arguments could be anywhere from 1 to 5.  I would prefer not to use a dedicated stored procedure for this (or XML), but if there is some elegant way specific to , I am open to that.


This is part of my Discrete Math homework and I have no idea how to solve this.  I am given this sequence: $8, 8, 7, 7, 6, 6, 4, 3, 2, 1, 1, 1 $  I have to check whether it is graphic or not.   How do I go on about doing that? Haven't done anything like this before so I'm a bit puzzled. I'm not sure how to solve this, do I have to plot this sequence or what?

I'm currently starting a course about Graph Theory, and I've been explained about the Havel & Hakimi degree sequence. However, I'm not too sure about it yet. First of all, I want to know if I understand it correctly, so I'm going to try to explain what I think the theory proves.  First, I've shamelessly stolen the following statement from the presentation:    Okay, so what I want to ask is the following.   What does "is graphic" mean exactly. Does that mean it's a graph? I know stupid question, but I cannot think of a degree sequence that's not a graph... What's the practical use of this. What problems could you solve with this.


For example there is no VirtualBox, Texmaker, LyX, calibre, Redshift.  I have ran sudo apt update and sudo apt full-upgrade. I have not used BleachBit. The only thing wrong in my computer seems to be that I often get an error message like this one when I run sudo apt update:  AppStream system cache was updated, but problems were found: Metadata files have errors: /var/cache/app-info/xmls/fwupd.xml Reading package lists... Done E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh-cache > /dev/null; fi' E: Sub-process returned an error code   , which I would also like to fix by the way.  Things I tried that did not help:  As advised in , I ran sudo apt install --reinstall libappstream3 and then sudo apt purge libappstream3, and then I also restarted my computer. Then I ran sudo apt install --reinstall libappstream3 again sudo apt install --reinstall libappstream4 and I restarted the computer again.

I cannot install any package. It seems the command apt-get update must be run but it throws some errors:  $ sudo apt-get update Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]      Hit:2 http://ve.archive.ubuntu.com/ubuntu xenial InRelease                      Hit:3 http://ve.archive.ubuntu.com/ubuntu xenial-updates InRelease              Hit:4 http://ve.archive.ubuntu.com/ubuntu xenial-backports InRelease            Fetched 102 kB in 23s (4337 B/s)                                                *** Error in `appstreamcli': double free or corruption (fasttop): 0x000000000210f4b0 *** ======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7fac8d8317e5] [...] Aborted (core dumped) Reading package lists... Done E: Problem executing scripts APT::Update::Post-Invoke-Success   'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli;   then appstreamcli refresh > /dev/null; fi' E: Sub-process returned an error code


I want to ask two different questions with the same title on Stack Overflow. Is this possible? If it is not then why can I not? I have two different purposes for the same title. We cannot explain our whole problem in the title. That's why we should go for the body part for giving more clarification. I want my title to be the same for the two posts, but the body parts to be different.

This feature request is a response to  Two days ago,  suggested that we . However, given that  (hat tip ) as well as ...  262  103   ... I suggest that we take it a step further. Let's extend the heuristics for detecting—and blocking—low-quality questions to enforce unique titles, or at least flag new questions with duplicate titles automatically. We can leave the precise heuristics of detecting a duplicate title up to the Stack Overflow development team. I have no delusions about the fact that a few questions will "slip through the cracks." The goal here is to be proactive about minimizing the number of duplicates, and I think that the best place to start is the existing heuristics for detecting low-quality questions. After all, duplicate question titles are bad for a number of reasons: They often indicate a question that is itself a duplicate, but perhaps just as importantly, they decrease the signal-to-noise ratio when searching for questions. I honestly can't think of any reason that duplicate question titles are helpful, unless you are asking for a solution to the same problem in a different programming language. Even then, I think that it would be acceptable to rephrase the question to say "How do I do X in (insert programming language here)?"  makes a good point about the potential problems with this solution:  I have a hunch that if we do that, people will find ways to circumvent it (changing case or punctuation, adding random spam), and we'll end up stuck in a an arms race.  We may get stuck in an arms race with some users, but I honestly think that many people new to Stack Overflow just don't understand the etiquette of asking questions here. If we could even convince people to rephrase their question more clearly 20% of the time, I think that it would be a tremendous boon to the community. Furthermore, remember that heuristics for low-quality questions already exist, arms race or no.


I've always thought refractive index is dependent on the density of the material. The more denser, the more refraction. But kerosene whose density is higher than water has refractive index less than water. On running a google search,i found out that it is dependent on the atom types.But i am unable to understand how.Can someone please give me a simple explanation?

Optical density is a measure of the refracting power of a medium. In other words, the higher the optical density, the more the light will be refracted or slowed down as it moves through the medium. Optical density is related to refractive index in that materials with a high refractive index will also have a high optical density. Light will travel slower through a medium with a high refractive index and high optical density and faster through a medium which has a low refractive index and a low optical density. So to restate the question, why do optical media have different refractive indices?


Someone has hacked my website recently & changed the codes. I have changed the cpanel password & banned some IPS. but still they are posting some content to database using a URL. punadirallu.org/newsitem.php?id=513. actually there is no newsitem with that id. & even if they open that URL, the iP ban script in the header section should block them from opening the page. I don't know how it is happening. Please suggest.

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


Let $X$ be Geometric($p$). As an exercise from the book Probability Essentials, 2nd edition (Jacod, J., Protter, P., 2004, p.34), I have to compute $E[1/(1+X)]$. The answer is $\log((1-p)^{\frac{p}{1-p}})$ but I kept getting $\log(p^{\frac{p}{1-p}})$ or $\log(p^{-\frac{p}{1-p}})$. I don't see the mistake in my own calculation. One of my calculation can be seen below: $$ $$ We have \begin{align*} E\left[\frac{1}{1+X}\right] &= \sum_{j=0}^{\infty}\frac{1}{1+j}(1-p)^jp\\ &= p\sum_{j=0}^{\infty}\frac{1}{1+j}(1 - p)^j\\ &= \frac{p}{1-p}\sum_{j=0}^{\infty}\frac{1}{1+j}(1-p)^{j+1}\\ &= \frac{p}{1-p}\sum_{j=0}^{\infty}\int_0^{1 - p} t^j \ dt \end{align*} The infinite series $\sum_{j=0}^{\infty}t^j$ converges uniformly to $\frac{1}{1-t}$ since $|t| < 1$, so we can interchange the integral sign and the sum sign $$\frac{p}{1-p}\sum_{j=0}^{\infty}\int_0^{1 - p} t^j \ dt = \frac{p}{1-p}\int_0^{1-p}\sum_{j=0}^{\infty}t^j dt = \frac{p}{1-p}\int_0^{1-p}\frac{1}{1-t}\ dt.$$ This is equal to $$-\frac{p}{1-p}\log(p) = \log(p^{-\frac{p}{1-p}}).$$  So my questions are: could you please point out the mistake? and what should I do so I get the correct answer. Or maybe it is a mistake from the book?  Edit. This is the definition of the Geometric distribution that is used in Probability Essential: $X$ has a Geometric distribution with parameter $1 - p$: $$P(X = k) = (1-p)^kp, \ \ \ \ \ \ k = 0, 1, 2, 3, \dotsc$$

Let $X$ be a random variable with a geometric distribution with parameter $p$.       Calculate $\Bbb E[1/(1+X)]$   I've looked at answers online but still do not understand how to solve this.   Specifically, I do not understand how to to get from $$\frac{p}{1-p} \sum_{x=0}^\infty (1/(1+x))((1-p)^x+1)$$  to  $-p\ln(p)  /(1-p)$.


Is there a way to save or export a tex file so as to produce a jpg/jpeg/png file?

Sometimes it's impossible to upload .pdf, .dvi and .ps files (usually images of diagrams generated with TiKZ in my case). There, one wishes to obtain a way to export them directly to a .png or some other pic-like file extension. Unfortunately the result I get by taking a snapshot of my .pdf is awful.  Which is the better way to get, say, a .png out of a LaTeX base code?


I can't install Skype for Ubuntu 12.04. Downloaded from official Skype site, but cant install. All the time same mistake something about i386. What’s wrong?

Note: The legacy Skype for Linux application (v4.*) is now discontinued and was removed from Canonical’s partner repositories, so this question and its answers are obsolete. Please refer to  of our .  Skype 4.3 is just released with considerable improvements. As a regular Skype user I want to use the latest Skype on my Ubuntu 14.04, but there is no updates from Update Manager. Even in Skype website only Skype 4.3 is available only for Ubuntu 12.04. Is there anyway to use this latest Skype on Ubuntu 14.04 or how much we have to wait for the update?


I am not clear on when the word "that" can be omitted in a relative clause. I only know that when the modified noun is the object in the clause, the antecedent "that" can be omitted. Are there any other such situations? How about the following sentence:     Students should be skeptical about everything they are told.   I am not sure whether everything is the object, and if not, whether this sentence is correct.

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?


This morning, I updated my MacTeX installation to the 2015 install. Unfortunately, something is now having some trouble with the font (Century/Century Schoolbook) that I use most [edit: everything worked fine before]. I'm a relative amateur with TeX and couldn't fix the issue with a couple hours of Googling, so here I am. Help!  The issue appears to be that fontspec and/or xdvipdfmx (whatever that is) are having trouble finding certain fonts on the computer. So some fonts work, others just don't. My investigations suggest that the fonts that are having trouble appear to be ones that came with MS Word—all of the offenders so far were originally located in /Library/Fonts/Windows. I moved them to the main folder but that didn't help, so I don't know what it is that's making these specific fonts invisible or uncooperative.  I've seen two similar errors. First, e.g., with the Century font. This code:  \documentclass[12pt]{article}  \usepackage{fontspec} \setromanfont{Century}  \begin{document} This is a test. \end{document}   Produces this error and refuses to compile/typeset:  xdvipdfmx:fatal: Cannot proceed without the font: /Library/Fonts/Century   But with other fonts, e.g. Colonna, I get something slightly different. This code:  \documentclass[12pt]{article}  \usepackage{fontspec} \setromanfont{Colonna}  \begin{document} This is a test. \end{document}   Produces this error and refuses to compile/typeset:  /Test.tex:5: fontspec error: "font-not-found"  !  ! The font "Colonna" cannot be found.

I've tried following the instructions at  But, when I try to run the small file  \documentclass{article} \usepackage{fontspec} \newfontfamily\myfont{Lucida Calligraphy} \begin{document}  Hello \myfont Hello  \end{document}   I get the following error  xdvipdfmx:fatal: Cannot proceed without the font: /Library/Fonts/Microsoft/Lucida Calligraphy   The font is in that directory.  I found the following similar request  But I'm not finding the provided answer very helpful: I don't know what fondu is, nor, even if I did have this utility(?), I don't know how to use and am very nervous about tinkering in a library which is not specific to the user.


So I'm trying to find "Wrocław" in my Mysql table with collation utf8_general_ci.  In PHP, I'm using this code  $query = $mysqli->query(" SELECT *    FROM locations  WHERE location    LIKE 'Wrocław' ") or die(mysqli_error($mysqli)); while($row = mysqli_fetch_array($query)) { echo'found it'; exit; }   However, I'm not getting any results. I will get a result when searching for "Barcelona". So I'm guessing that the problem is due to the funny character "ł".   When entering the above Query in PhpMyAdmin, I am in fact finding the row containing "Wrocław" which is the expect result.  Any idea why it's not working on the PHP side? I've also tried to previously use mysqli_real_escape_string on Wrocław  Thanks!

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


Sometimes the attributes of an operator can change quite dratically the output for the end user.  is there a way to make the description of this operator adaptive to the attribute ?   exemple in the script below:  class SCATTER_OT_print(bpy.types.Operator):     bl_idname      = "scatter.print"     bl_label       = ""      pref : bpy.props.StringProperty()     bl_description = "print: " + pref #Adaptive desctiption ?       def execute(self, context):         print(self.pref)

I'd like to update the label of an operator when it's called. But this :  def execute(self,context):     self.bl_label = "good night"   ... apparently doesn't work if the bl_label property has already been defined. Am I wrong ?


I can't find this, but it could be I'm not sure how to search for it. I have a lot of icons in my Launcher. Is there a way to combine some, i.e. Firefox and Chrome or LibreOffice and gedit or graphics editors in one "folder"?

I have a large number of .sh scripts for opening ssh connections to various remote machines. These .sh scripts are grouped by staging/test/production/etc  In Gnome I had a series of entries in the Places menu, one for each type of system:  Places | + Staging |       +Machine 1 |       +Machine 2 |       +Machine 3 +Test |       +Machine 4 |       +Machine 5   What are my options for having this kind of layout in the Unity launcher? I suppose I'm really looking for a drawer or similar that I can mouse over to find the correct script.  If I had only a few scripts I could just pin them to the launcher one by one, but I've got about 200!  Perhaps there is a Lens for doing this?


I was able to succesfully vote to close , when I had just 909 rep.    I believed I need 3000 to cast close votes? Is this some kind of a feature or was it a bug?

I just discovered I can cast a  on meta at 288 reputation, even though the privileges list marks it at 3k.   Is this a bug?   I do have the "Close Vote" privilege on SO. The question was my own, can I always vote to close my own questions?


My little brother was fooling around with the keys and I cant get it to break blocks. I can place blocks and perform other tasks.  I tried everything in settings but it just wont break blocks.  If anyone can explain how to fix this that would be great because right now I am totally MineCraftless and I need to play that game!!!!  Thank You

I'm playing on a Survival world with cheats on, "easy" difficulty, and at night in-game. I didn't have a sword or anything to make a sword with, and I was starving, so I switched to Creative to give myself a stack of food and a bed to set my spawn point. When I switched back to Survival, I couldn't destroy or place blocks. I'm on single player, and my Internet is fine, and I can destroy blocks still if I switch to creative. I've tried resetting the button one, and reloading the map, and it still doesn't work. I've even tried deleting everything I gave myself in Creative. This happened before on a different world and I ended up deleting it.  This only happens on this world. How do I fix it?  If I know I'm in the correct game mode, what else can cause this?  Are there different causes in multiplayer?


I was working on the computer and installed gnome tweak tool I went to the extensions and tried to turn on system monitor ext. However, for some reason, it locked the computer up and now when I log in it keeps looping back to gdm3 login screen.

My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M


I'm from Pakistan and live in Turkey.  I have one year residence permit of Turkey.  Can I apply for schengen visa from Turkey and what will be required documents for it

Is it generally possible to apply for a visa to another country from a country that is not my country of origin? As a concrete example to clarify, I have a German passport and I can travel without applying for a visa beforehand through France, Spain, Morocco, Western Sahara, Mauritania, Senegal, Gambia and Guinea-Bissau, but in order to enter Guinea, I need to apply for a visa. Is it possible to do this from Senegal (for example)? Also, which embassy will be responsible for that?


But the proof here below is specially elegant.  Is there any function $f$ such that $f$ has a local minimum at $x$ but $\nabla f(x) \neq 0$?  Only assumption on $f$ is that it has to be differentiable at $x$ so that I can write $\nabla f(x)\neq 0$  to ask you this question.

Let $f: \mathbb R ^n\to\mathbb R$ be a differentiable function.   If $x_0\in \mathbb R^n$ is a point of local minimum of $f$, then $\nabla f(x_0) = 0$.   Where can I find a proof for this theorem? This is a theorem for max/min in calculus of several variables.  @Peter Tamaroff   Here is my attempt:  Let $x_0$ = [x1,x2,...xn]  Let g$_i$(x) = f(x$_0$+(x-x$_i$)e$_i$) where e$_i$ is the ith standard basis vector of dimension n.   Since f has local min at x$_0$, then g$_i$(x) has local min at x$_i$.   So by Fermat's theorem, g'(x$_i$)= 0 which is equal to f$_{x_i}$($x_0)$   Therefore f$_{x_i}$($x_0)$ = 0 which is what you wanted to show. Is this right??? Any comments would be appreciated.


I have noticed recently that a few websites display incorrectly: www.dropbox.com and www.mediafire.com. They appear to only be loading a very minimal version of there websites (see attachments). All other websites appear to load and function as expected.  This issue happens with both Firefox and Chromium. I also have the same issue with both Internet Explorer and Firefox when run in in Virtual Box with Windows Xp as guest.  These websites display as expected on my other pc which has windows as the OS.  This leads me to believe it is more than an Internet browser issue, but I have tried the standard troubleshooting steps anyways: clearing cache, cookies, ect...  I thought it could be an user agent issue, but it seems fine to me.  Any ideas?    OS Version: Ubuntu 13.10.2 64 bit  User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:25.0) Gecko/20100101 Firefox/25.0  Firefox 25.0.1 Chromium 30.0.1599.114  No Proxy, No Software Firewall installed, Have disabled all browser add-ons     on Firefox:       on Chromium:

whenever I go to  or  the page loads like this:    How can I fix this?


The CSV files that need to be read are quite large, but each of them only has only one line (from kb to gb), one large line. I tried to use the code below, but the maximum size can be only reached by 1000000, adds one more 0 resulted Segmentation fault. I read that the buffer has a limitation, but is there another way just to read that one large line and put then in an int array? or do I really need to use mmap? Thanks a lot! struct IntArrLen {  int length;  int max_index;  int* arr; };   struct IntArrLen readInt(char* str){     struct IntArrLen intArr;     intArr.length = 0;     intArr.arr = NULL;      char file_name[100];     strcat(file_name, str);     FILE *fp;     fp = fopen(file_name, "r");      if (!fp){         return intArr;     }      char* token = NULL;     // define the maximum size of line     int max_size = 1000000;     char row_content[max_size];     int* arr = (int *) malloc(sizeof(int) * max_size);     fscanf(fp, "%[^\n]", row_content);      int count = 0;     token = strtok(row_content, ",");     while(token != NULL){         arr[count] = atoi(token);         token = strtok(NULL, ",");         count ++;     }      intArr.length = count;     intArr.arr = (int *) malloc(sizeof(int) * intArr.length);     memcpy(intArr.arr, arr, sizeof(int) * intArr.length);      free(arr);     return intArr; }    the CSV file is something like this: 1245,2234532,23243523,235235325,325362436,5473658658,65879659,....

The following code is generating a stack overflow error for me  int main(int argc, char* argv[]) {     int sieve[2000000];     return 0; }   How do I get around this? I am using Turbo C++ but would like to keep my code in C  EDIT:  Thanks for the advice.  The code above was only for example, I actually declare the array in a function and not in sub main.  Also, I needed the array to be initialized to zeros, so when I googled malloc, I discovered that calloc was perfect for my purposes.  Malloc/calloc also has the advantage over allocating on the stack of allowing me to declare the size using a variable.


The software I want to run requires php 7.1.11, phpmyadmin 4.7.7 and SQLSRV extension. Is there a way to install required packages without having to build them from source? I need a specific 7.1.11 I was only able to get 7.1 or 7.2 from the oerdnj repository Thanks

I am trying to update to install PHP 5.5, 5.6 or 7.0 in Ubuntu 12.04/14.04/16.04 LTS, and I can only get PHP 5.3.10 for Ubuntu 12.04, PHP 5.5.9 for Ubuntu 14.04 or PHP 7.0.4 for Ubuntu 16.04 using official repositories (using apt-get).  I'm not really sure how to do a manual update – as I need:   to play around with the new(est) PHP features to install older PHP version due support in the software


Assume that I have a table with N columns. And I need a subset for all combinations of columns. For example, If there are C1,C2,.....,Cn columns, I need   1D = {C1,C2,C3,C4,.....,Cn} 2D = {C1C2,C2C3,C1C3,.....,Cn-1Cn} // 2D is all combination set for 2 columns. 3D = {C1C2C3,C1C2C4,C1C2C5,......}   ...  I will use Vector<Vector<String>> setofNDSubset. (java)  I think it will be Vector(1D,2D,3D,......,ND). And I use jdbc.  Column number should be less than 10.  I need some advices for you. Thanks.

I want to write a function that takes an array of letters as an argument and a number of those letters to select.   Say you provide an array of 8 letters and want to select 3 letters from that. Then you should get:  8! / ((8 - 3)! * 3!) = 56   Arrays (or words) in return consisting of 3 letters each.


Is there a way to disable the save password bubble in Chrome using javascript?  I need to make sure no users are able to use that feature.  This is a Chrome specific problem.  works for Mozilla, but not for Chrome. I don't want the bubble or option to even show up. autocomplete=off does not work in Chrome.

One of the joys of working for a government healthcare agency is having to deal with all of the paranoia around dealing with PHI (Protected Health Information). Don't get me wrong, I'm all for doing everything possible to protect people's personal information (health, financial, surfing habits, etc.), but sometimes people get a little too jumpy.  Case in point: One of our state customers recently found out that the browser provides the handy feature to save your password. We all know that it has been there for a while and is completely optional and is up to the end user to decide whether or not it is a smart decision to use or not. However, there is a bit of an uproar at the moment and we are being demanded to find a way to disable that functionality for our site.  Question: Is there a way for a site to tell the browser not to offer to remember passwords? I've been around web development a long time but don't know that I have come across that before.  Any help is appreciated.