$$\int^2_{-2}\frac{x^2}{1+5^x}$$  How do I start to integrate this?  I know the basics and tried substituting $5^x$ by $u$ where by changing the base of logarithm I get $\frac{\ln(u)}{\ln 5}=x$, but I got stuck.  Any hints would suffice preferably in the original question and not after my substitution.  (And also using the basic definite integrals property.)  Now I know only basic integration, that is restricted to high school, so would prefer answer in terms of that level.


Error when trying to prevent SQL injection

I am using phpmyadmin to create a table for an assignment and I am trying to figure out how to prevent SQL injection but I'm getting some weird error and I am not sure why. I am trying to use the quote method to fix it but it's not working. Here is the code I have  try {   $conn = new PDO("mysql:dbname=*removed*;host=*removed*", "*removed*", "*removed*");   $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);    $firstName = $conn->quote($_POST["first_name"]);   $lastName = $conn->quote($_POST["last_name"]);   $house = $conn->quote($_POST["house"]);    $sql = "INSERT INTO my_table (last_name, first_name, house)   VALUES ('$lastName', '$firstName', '$house')";   $conn->exec($sql);   echo "
New entry successfully created.
"; } catch(PDOException $e) {   echo $sql . "
" . $e->getMessage(); }  $conn = null;   I looked at the textbook I am using and it says to use the $db->quote($_POST["var_name"]); to clean up the data, which is exactly what I do, but for some reason it's not working for me.   EDIT: The error message I am getting says this:  "INSERT INTO my_table (last_name, first_name, house) VALUES (''Allen'', ''Barry'', 'House1') SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Allen'', ''Barry'', 'House1')' at line 2   Any idea why?


How does the "computer fan with magnets" generator "work"?

This question is in relation to the following YouTube video:    In it, an electrical generator is shown consisting of a CPU fan with thin magnets attached to the fan blades. Allegedly, bringing another magnet close to the fan causes the fan to spin. The fan's motor is utilized as a generator to power a light-bulb.  Just to be clear, I know there's no such thing as "free energy". But I'm puzzled as to why the CPU fan rotates at all. It seems intuitively that the most you could accomplish by approaching another magnet to the fan is to set up an oscillating motion (rather than continuous rotation).  Several ways of "cheating" come to mind: A magnetic stirrer hidden under the table? But, in part of the video, the demonstrator holds the fan somewhat above the table. A small battery hidden somewhere on the fan? We don't get to see it from all sides, but it doesn't look like he's flipping a switch.  Some of the comments on the video speculate that the energy comes from demagnetizing the magnets, but this seems dubious. If the device "works" to any extent it seems the input energy would be in the form of work performed by the person moving the magnet. But can the fan be started spinning by motion of the magnet alone?


Why is the SE search not as powerful/intelligent as suggestion while asking questions

Many times when I search on Stack Overflow (or other Stack Exchange sites), I don't get any relevant results. So, I then proceed to ask a new question and VOILA!!! Stack Exchange is able to suggest me a probably question which may already have an answer. Why can't the search feature do this before I try to ask a question? The latest example I encountered is this. My question was (in exact words):  Not able to use specific imports in ansible module  When I did a search in Stack Overflow, I got 0 results.  So, I went to add a new question. But as soon as I just entered the question title, this is what I got.  And the question which is highlighted in the image matched my question exactly. So, why can't the Search feature be as good and suggest me this?


I have this issue: I have a java application that goes fullscreen and another application (of which I have no control) that must stay in the same place of the screen and always be shown. My application using the "rest" of the screen should also always be visible. Note, my application does not have any content in the overlapped area. Sidenote: the OS is unavailable to the user, these are "closed" appliances. Is there a way I can tell windows how to "stack" windows with such apps? This is a idea of how the whole layout should look like:  Another option could be to make my background transparent and not intercepting the events on that particular area.... but I don't think it's possible within Java.


Whats the difference between close and dispose in SQL?

I usually use below code, should it be right ?   using (SqlConnection myConn = new SqlConnection(ConnectionString))      {          using (SqlCommand cmd = new SqlCommand(sqlString, myConn))          {              myConn.Open();              rows = cmd.ExecuteNonQuery();          }          // TO DO .      }   Which one is prefer? Please tell me the difference between them. In my opinion: when Pooling is false both close and dispose will shut down the connection. When Pooling is true close won't shut down the collection ,but dispose would.


Convergence of the sequence $\sqrt{1+2\sqrt{1}},\sqrt{1+2\sqrt{1+3\sqrt{1}}},\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{1}}}},\cdots$

I recently came across this problem     Q1 Show that $\lim\limits_{n \rightarrow \infty} \underbrace{{\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{1+\cdots+n\sqrt{1}}}}}}}_{n \textrm{ times  }} = 3$   After trying it I looked at the solution from that book which was very ingenious but it was incomplete because it assumed that the limit already exists.  So my question is     Q2 Prove that the sequence$$\sqrt{1+2\sqrt{1}},\sqrt{1+2\sqrt{1+3\sqrt{1}}},\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{1}}}},\cdots,\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{1+\cdots+n\sqrt{1}}}}}$$ converges.   Though I only need solution for Q2, if you happen to know any complete solution for Q1 it would be a great help .  If the solution from that book is required I can post it but it is not complete as I mentioned.   Edit: I see that a similar question was asked before on this site but it was not proved that limit should exist.


Making bootable Windows Server 2016 installation USB stick

Is there an Ubuntu 16.04 counterpart to  ? I need to create a bootable Windows Server 2016 USB drive; since it contains file larger than 2Gb, mkusb and similar tools, which try to format the target as FAT32, fail.  unetbootin refuses to accept NTFS-formatted USB drive, either.  As far as I understand, the problem is in finding Linux counterpart for "bootsect /nt60" command, to copy Bootmgr boot sector to target USB drive.  Is it possible without actually using a Windows computer?


Smallest and largest values of $\|\vec{v}-\vec{w}\|$

So I have this problem (self learning linear algebra) and I try to solve it using the indicated steps. Question is: Am I right, is this a valid answer? Obviously for me makes sense but since I'm just starting with maths maybe there's something wrong:     If $\|\vec{v}\| = 5$ and $\|\vec{w}\| =3$, what are the smallest and largest values of $\|\vec{v}-\vec{w}\|$ and $\vec{v} \cdotp \vec{w}$?   EDIT   I'd moved my initial answer to a full answer. See below.


Number of points on a line in a finite projective plane

I've been reading some proofs regarding finite projective planes of order n, and often they start out by assuming that each line contains n+1 points. Is this a fact that follows from the axioms for finite projective planes? Or does this relate to the order of the finite field being projected? (for example in the Fano plane, does the fact that each line contains 3 points follow from the fact that there are 3 elements {0,1,2} in Z_2?) I haven't been able to find a clear explanation of this (clearly I do not yet have a solid understanding of how such planes are constructed). If someone could enlighten me that would be excellent.


More pythonic way to do this (string splitting)?

d is a string list where each item is composed of two parts (connected by a dot). I want to extract the parts before and after the dot for each string item.  Here is how I did it.  d = ['a1.b1', 'a2.b2', 'a3.b3'] b = [c.split('.')[0] for c in d] a = [c.split('.')[1] for c in d]   But I guess there is some more pythonic way?


I'm new to blender so please forgive the ignorance. Can anyone tell me the optimum specifications for my PC I need to efficiently run blender 2.8.?  Or would I do better to use a MAC. I am a visual artist and I have not ventured into animation...yet  Any advice would be appreciated Thanks


Determine overall Stack Exchange reputation rank

I have earned roughly 27k reputation points in total between all the Stack Exchange sites. I notice that when I follow or commit to an Area 51 proposal, I'm usually one of the highest on it when sorted by user reputation. How might one go about finding their rank of Stack Exchange reputation? We can do it individually per site, but that's not what I'm looking for exactly. I have considered something like... pulling a data.stackexchange query of all users with 10k+ rep on each site (just assuming there's not people with 8k rep on four different sites to sneak under the radar) and compiling a list that way, but that is a lot of work and isn't guaranteed to be accurate. And from what I can tell, the data query tool is not capable of hitting multiple databases. What are my options to solve this incredibly not important problem?


For a metric space $X$, show that if $F \subset X$ is closed and connected then for every pair of points $a, b \in F$ and each $\varepsilon > 0$ there are points $z_0, z_1, ... , z_n \in F$ with $z_0 = a$, $z_n = b$ and $d(z_{k−1},z_k) < \varepsilon$ for  $1 \le k \le n$. Is the hypothesis that $F$ be closed needed?   Actually, I tried to prove it by contradiction, i.e. let there exists distinct $a, b \in F$ and there does not exist any finite set of points in F such that the above condition holds . Then, $\exists \varepsilon>0$  such that for any finite set of points $\{a, z_0, z_1, ..., z_n\} \in F$, there is a positive integer $k<n$ with $d(z_{k−1},z_k) > \varepsilon$ , then for any $z \in F$, $z \ne a,b$ ; either $d(a,z) < \varepsilon$ or $d(a,z) \ge \varepsilon$, now as $F$ is connected, there is a $z$ with $d(a,z) = d(b,z) = \varepsilon$, then I can't approach .


I would like to place nodes with given distances relative to each other. For consistence with other drawings these distances have to be very accurate. Node border anchors are placed at the outer borders of the nodes (see pgfmanual 3.0.0, page 702). Therefore, effectively pgflinewidth (or fractions/multiples of it depending on the nodes shape) is added to the given distance (red nodes in the MWE).  A way to counteract this would be to subtract (fractions/multiples) of pgflinewidth (blue nodes in the MWE). Another alternative could be to place the nodes w.r.t. their centers. In this case, one would need to know the nodes' widths beforehand which might not be easy for arbitrary node shapes.  My question: Is there an easy way to have node border anchors centered on the borders?  \documentclass{standalone}  \usepackage{tikz}  \begin{document}          \begin{tikzpicture}[ultra thick, MyNode/.style={draw, minimum height=1cm}]                  \draw[step=1cm,gray,ultra thin] (-1cm,-3cm) grid (5cm,2cm);                  % default case                 \begin{scope}[red]                     \path (0,0) node[MyNode, anchor=south west, minimum width=1cm] (n1) {};                     \path (n1.east) ++(1cm,0) node[MyNode, anchor=west, minimum width=2cm] {};                 \end{scope}                  % supstract line width                 \begin{scope}[blue, shift={(0,-2)}]                     \path (0,0) ++(-0.5\pgflinewidth,-0.5\pgflinewidth) node[MyNode, anchor=south west, minimum width=1cm] (n1) {};                     \path (n1.east) ++(1cm,0) ++(-\pgflinewidth,0) node[MyNode, anchor=west, minimum width=2cm] {};                 \end{scope}      \end{tikzpicture}  \end{document}


What can I do that all tabs stay in the foreground all the time?  Imagine you have two windows open; one is, for example, Google Chrome, this one is fullsize. The second one is a normal sized terminal. If I do something in the terminal it's in the foreground, but if I then click something in the browser, the terminal will go to the back. What can I do to hinder the terminal or any other window to going to the background when it loses focus?


How hoisting concept actually works with functions and variables in javascript

What the difference between Creation Phase and Execution phase in hoisted variables and functions. also how Execution Context is working at this case in javascript console  Refer to this example :  b(); console.log(a);  var a = 'Hello World';  function b() {     console.log('Called b!'); }   Output:  Called b! undefined   How can you explain this scenario:   in function case it returns Called b!  in variable case it returns undefined


Joint distribution of $X+Y$ and $\frac{X}{X+Y}$

Let $X$ and $Y$ be two random variables i.i.d $U(0,1)$. Find the joint pdf of $T = X+Y$ and $U = \frac{X}{X+Y}$ and the marginal densities of $T$ and $U$  My attempt:  We will have the following transformation:  $X = TU$ and $Y = T - TU$. The jacobian is $J = -ut -t(1-u) = -t$ and the joint pdf:  $$f_{T,U}(t,u) = I_{(0,1)}(tu)I_{(0,1)}(t-tu) |t|$$  where $I$ is the indicatr function  Note that $U$ and $T$ will be jointly defined in the following region:  1) $0 < t < 2$  2) $0 < u < \infty$  3) $0 < tu < 1 \Rightarrow t<\frac{1}{u} (u>0)$  4)$ 0 < t -tu < 1$  4.1) $u < 1 (t>0)$  4.2) $t < \frac{1}{1-u}$  Integrating in respect of $t$, I could obtain th right pdf of $U$ because I know the answer. But in respect of $u$ I couldn't. Is my region wrong?  P.S: I know how to obtain the pdf of $X+Y$ using other ways, I want it using this joint distribution.  Thanks!


I have been trying to align the div (table) to centre. I changed the margin and the width and it works fine but when the screen is small, I get the scroll down/right bar as shown below :    How can I change that? I tried putting a max-height and playing with the margins (set to 0) but with no success.   HTML :

####

 MORE

   CSS :  .container {   max-height: 465px; }  .table {   position: relative;     width: 50%;     max-width: 320px;     min-width: 270px;     margin: 30px auto;   background: #fff;   text-align: center;   height: auto;   margin-bottom: 90px;   -webkit-transition: all .3s linear;   transition: all .3s linear; }


How to prove that there are infinitely many primes of form $6n+1$?

We know that all primes greater than $3$ are of form $6n+1$ or $6n-1,$ but how do I prove that there are infinitely many of the form $6n+1$?  Please prove it without Dirichlet's theorem.  Note:  This question is not a duplicate of ; there people are discussing about $6n-1$.


How to redirect html button -> Servlet -> another html page?

I have a html page with 2 buttons with the same form action (When the user presses a button, the form redirects it to a servlet and then in that servlet, I want it to redirect to another html page based on the button pressed in the html page).   Html page  <form action ="ManageEmployeeRedirect" method = "post">  <input type="submit" value="Create New Employee Account" name="ID1">

 <input type="submit" value="Update Existing Employee Account" name="ID2">  </form>
     Servlet  import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*;  public class ManageEmployeeRedirect extends HttpServlet {       protected void processRequest(HttpServletRequest request, HttpServletResponse response)             throws ServletException, IOException {         response.setContentType("text/html;charset=UTF-8");         PrintWriter out = response.getWriter();          String name = request.getParameter("ID1");         String name2 = request.getParameter("ID2");           if("ID1".equals(name)){             RequestDispatcher rs = request.getRequestDispatcher("index.html");             rs.forward(request, response);         }         else if("ID2".equals(name2)){              RequestDispatcher rs = request.getRequestDispatcher("changePassAdmin.html");              rs.forward(request, response);         }     }     @Override     protected void doPost(HttpServletRequest request, HttpServletResponse response)             throws ServletException, IOException {                processRequest(request, response);           }      @Override     protected void doGet(HttpServletRequest request, HttpServletResponse response)             throws ServletException, IOException {                processRequest(request, response);     } }


How to wire GFCI outlet to aluminum wiring?

How to wire gfci to aluminum wiring. Have not tried to yet, i want to be sure as to how first. I've been told of using no-ox and 6" copper pig tails.


Prove if $7\mid a^2+b^2 \longrightarrow 7\mid a$ and $ 7\mid b$

Prove if $7\mid a^2+b^2 \longrightarrow 7\mid a$ and $7\mid b$  What I did:  I found the possible remainders for $a^2$ are $0, 1, 2$ and $4$.  I think I should say $r_7(a^2)+r_7(b^2)$ can't equal any multiple of $7$ unless both of them are $0$?  And if both of them are $0$, that implies $r_7(a)=0$ and $r_7(b)=0$  Am I correct? How can I explain this in mathy terms?


Short story from many years ago: the ancient, brilliant, cruel race was Earthlings

I may have encountered this short story in Asimov's Science Fiction magazine. Human explorers encounter an alien spacecraft. Aliens are cautiously friendly, but then tell the humans about an ancient, brilliant and cruel race of beings that conquered and destroyed every civilization they encountered. They were finally defeated and destroyed, or so it was thought, but their home world was never found. It turns out that this powerful, vicious race was in fact, Earthlings.


Lock down OSX 10.7.5 app into kiosk mode?

I want to run an app in 'kiosk' mode for public unattended access via touch screen (no mouse or keyboard attached). I can already automate a network user logon and then the app launches (but only in last state - not necessarily full screen - which I want) I know with Workgroup Manager you can hide the dock, use simple Finder etc...but need something more powerful. Ideally it needs to monitor if the app crashes out and restart it / log limited user off and back on again.  Thanks  Phil


Why do Sith even acquire apprentices if they know the apprentice will kill them?

So why do Sith even seek and acquire apprentices if the Rule Of Two necessitates that the apprentice must crave his master's power and eventually kill him. Do the Sith know this will happen and just not care or are they suicidal or what?


setting a margin or padding for a 100% height grid without scrollbars

I've got a grid layout. I want to add a 5px margin all around it but doing so adds a scrollbar. Is it possible to set a margin without having a scrollbar added?   function toggle() {   document.querySelector(".container").classList.toggle("withMargin"); } html, body, .container {   height: 100%;   margin: 0; }  .container {   display: grid;   grid-template-rows: 50px 1fr 1fr;   grid-template-columns: 300px 1fr 1fr;   gap: 5px 5px;   grid-auto-flow: row;   grid-template-areas: "logo header header" "nav-one main main" "nav-two main main";   background-color: black; }  .main {   grid-area: main;   background-color: lightcoral; }  .logo {   grid-area: logo;   background-color: lightcyan; }  .header {   grid-area: header;   background-color: lightgoldenrodyellow; }  .nav-one {   grid-area: nav-one;   background-color: lightgray; }  .nav-two {   grid-area: nav-two;   background-color: lightgreen; }  .container.withMargin {   margin: 5px; } <!DOCTYPE html>

<button onclick="toggle()">toggle .container margin</button>

logo

header

nav one

nav two


Let $X\subset \mathbb{R}$ Lebesgue measurable, $|X|<|\mathbb{R}|$, is it true that $X$ is null?

Let $X\subset \mathbb{R}$ Lebesgue measurable, $|X|<2^{\aleph_0}$, is it true that $X$ is null?  Of course I am not assuming the Continuum Hypothesis.   EDIT: It might be helpful to know that all Borel measurable sets have cardinality either $\aleph_0$ or $2^{\aleph_0}$. Then a measurable set of cardinality strictly between those two must be Lebesgue but not Borel measurable.


I have a huge word-list file. I want to remove numeric only lines.  Can I do this using sed or something else?  Input:  Pass123 Dexg43 111116 246814 dancer@ Cody1234 Cody1234   Expected Output:  Pass123 Dexg43 dancer@ Cody1234 Cody1234   I need lines with 11116 and 246814 removed, the rest are ok.


TeX Live packages administration, tlmgr don't work on Open Suse

I want to know how install and manage packages for TeX Live 2011 on Linux Open Suse; with Windows systems it is possible to manage packages for TeX Live with the Package Manager program included in the MiKTeX installation, but I don't now how to install and manage packages for TeX Live on Linux. I installed TeX Live 2011 with YaST2 Software Management but when I want execute the command tlmgr I get the following message:       dev@dhcppc1:~> tlmgr If 'tlmgr' is not a typo you can use command-not-found to lookup the package that contains it, like this:     cnf tlmgr   So, how I can manage packages if tlmgr is not found or does not work? How I can "reinstall" tlmgr?  My TeX Live version is: TeX, Version 3.1415926 (TeX Live 2011) My OS:  Open Suse 12.2


What is the difference between the two commands? Which one is better to emulate another user when wanting to do something as that user?  sudo -H -iu USER command  and  su -l USER -c command


So I know for an observer outside the event horizon, objects become infinitely time dilated at the event horizon, making them look as if time stopped for them. If I then throw an electron into a black hole with known momentum, and it "freezes" at the event horizon, don't I now know both its momentum and position, violating the Uncertainty Principle?


Here my code. I want remove from vector all elements with successfully called method 'release'.  bool foo::release() {     return true; }  // ... vector<foo> vec; // ... remove_if(vec.begin(), vec.end(), [](foo & f) { return f.release() == true; }); // ...   But remove_if not deleting all elements from vector vec. How remove_if works?


Sorry if this is a duplicate, but could we have a search bar next to the page numbers so that we can easily find the nth page? For example, there are 740 pages in Meta SE unanswered, so it would be difficult to find the 100th page without changing the URL manually. It would be great to have this additional feature, perhaps next to the 'next' button?


For instance you're driving and there's a car ahead of you, it is very slow and hesitant. You find it irritating, what do you call the driver? Is there an expression to describe him or her?


I have recently switched from firefox to google chrome on Ubuntu 16.04.  The keyring application is really starting to annoy me.  It keeps prompting me for password for no apparent reason.  Also google chrome randomly seems to forget passwords for some sites.  I would like to completely disable the keyring feature and have it just remember my passwords without me needing to enter another password.  I do not care to much about security since this is my personal system that no one else has access to.  How can I make chrome remember my passwords without every prompting me with keyring.


Let $a$, $b$, and $c$ be positive real numbers. Prove that  $$\sqrt{a^2 - ab + b^2} + \sqrt{a^2 - ac + c^2} \ge \sqrt{b^2 + bc + c^2}$$  Under what conditions does equality occur? That is, for what values of $a$, $b$, and $c$ are the two sides equal?


Open dialog from fragment(fragment's view=null)

in my app, i have a TabLayout that every tab is a separate fragment. I open dialog in one of this fragment. in my dialog contain a list that I want when I clicked to list item, The content of item pass to in textView in A number of fragment         public class ReadingFragment extends Fragment{    TextView textView;    View view;    FloatingActionButton actionButton;     @Override     public View onCreateView(final LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        view = inflater.inflate(R.layout.fragment_read, container, false);          textView = view.findViewById(R.id.txtSaved);        actionButton = view.findViewById(R.id.floatingActionButton);          actionButton.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 DialogSearch search = new DialogSearch();                 search.show(getActivity().getSupportFragmentManager(),"baranAbFa");         }     });    }      public void setData(String x){        textView.setText(x);    } }     This MainActivity Code(the method that received data from Dialog and pass to Fragment  ):   public class MainActivity extends AppCompatActivity{       public void setGetAndSend(String name){         Fragment frags= viewPagerAdapter.getItem(2);         ((ReadingFragment) frags).setData(name);         Toast.makeText(MainActivity.this, name, Toast.LENGTH_SHORT).show();     } }   And this in My Dialog Class And method that handle ItemClickListener:  (strings is a list that displays in list View)  public class DialogSearch extends DialogFragment {     View dialogView;     @Override     public Dialog onCreateDialog(Bundle savedInstanceState) {     super.onCreateDialog(savedInstanceState);      dialogView = getActivity().getLayoutInflater().inflate(R.layout.search_dialog, new RelativeLayout(getContext()), false);      final Dialog builder = new Dialog(getActivity());      listViewSearch.setOnItemClickListener(new AdapterView.OnItemClickListener() {                 @Override                 public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {                      ((MainActivity)getActivity()).setGetAndSend(strings.get(i));                  }             });     } }   And when run and click to list item this error is occured: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference also View in ReadingFragment too is null


Why can't a single Ethernet cable carry 2 independent connection?

A Ethernet cable has 4 pairs of data lines. In normal conditions only two pairs are used, one as a Tx pair and another as Rx pair. So two pairs are left unused. Is it possible to make use of these 2 pairs to carry another independent connection?  Of course I am expecting some obstacles. Maybe it will lead to a lot of noise and subsequent signal degradation. Can this be avoided by using a different color code?  It should be noted that I am not using Gigabit hardware. I just have 10 Mbps. So if I give this a try, will my connection speed be further reduced?   Another reason why this solution will be great is because I have only one power outlet in my room.


The Messages app doesn't recognise numbers that are saved in Contacts app

I am using Contacts OSX and iOS app's and they both synced into iCloud and I have opened them to check if the contacts are the same on my phone and Mac and they are.  However when I receive an iMessage or Text message in Messages OSX it doesn't recognise the number even though that number is saved in Contacts.


A limit of n times sine values at factorially spaced arguments

Evaluate the following limit   $\lim\limits_{n \to \infty} n \sin(2\pi \;e \;n!)$  I have no idea how to proceed forward?   Answer for above is $2\pi$ but I don't know how this comes about.


What is the advantage of using wp_mail() over mail(). Codex says they're similar, but they seem to be very similar.


Two Calendar alerts not working since iOS 9 update

Since the iOS 9.0.x update, I can't set two different alerts on calendar entries.   Whatever I put in for the first or second alert overwrites both time periods.   Is there a fix or workaround for this?


Word/phrase for the activity of hiding mistakes

What word/phrase can I use to describe the activity of hiding a stupid mistake/incident, such as quickly cleaning up tea spilled by accident before anyone could notice?


Boost Serialization and Win32 file handle

I have a problem about using Boost.Serialization with Win32 file handle. I want to serialize something to some Win32 file handle created by ::CreateFile with some special flags (FILE_FLAG_DELETE_ON_CLOSE & FILE_ATTRIBUTE_TEMPORARY). But I learnt that Boost.Serialization only works with std::ostream.  Any solution?


Installing a persistant Ubuntu OS onto a USB without re-installing it to the hard-drive

I have tried uunetbootin and mkusb, to try to install Ubuntu 18.0.3 onto a usb, as an OS, not as an install disk.  With uunetbootin, it just over-writes the Ubuntu on my laptop, and installs an 'install' disk onto the usb, even when i select only the usb.  With mkusb, it just freezes when I choose the usb as the target disk to install to, with persistence, and choose the live install dvd of 18.04.3 in the dvd drive as the source disk.  The only way I have been able to do it, is by locking the hard-drive in the bios (intentionally entering the wrong password on start-up), and then F12 booting from the Install DVD. Then when Ubuntu loads, clicking on install, and choosing the usb as the target device.  Ubuntu gives an error message of being unable to write/close the hard-drive, which I just click 'ignore', and after 3 times of this message, it installs a perfect OS with persistence onto the usb.  Works for me on a Dell laptop, but surely there must be a easier,simpler way ??  Thanks,  vedaal


Regular expression: matching word boundaries

I'm having trouble understanding the way boundaries work.  Say I'm trying to scrape an HTML string which contains:
foo

bar
   Say I want to match each
..
   segment? I tried /
.*
 but I guess because its greedy it just takes the whole line..how do I workaround that so I have two separate matches?


I noticed something, after reviewing many suggested edits audits in the past few months. The suggested edit audits generate slowly, so it is pretty easy to determine if a suggested edit is an audit. In suggested edits, the system generate audits using a system, but it takes a lot longer time to show up then the normal reviews. Could this be improved?


16.04 CIFS "Host is down" but they are not

I have my CIFS setup in fstab and they are working as they are supposed to on boot. They mount as they should and work for a while. Out of nowhere it seems (could be after unlocking machine etc) I get "Host is down" error trying to access it. I have multiple and they are all down. They are also shared from the same server. At this time i check on a windows computer and an outdated 14.04 machine and they are up and functioning as they are supposed to. After clicking around on the shares in nautilus and getting repeat errors they will just start working again. To access a share that is "down" takes about 2-3min of randomly clicking different mounts and going back to the first one when automagically it shows the data in the mount point.  I do not have this problem on 14.04 machines that have not been updated in a while. All of those machines are fully functional and the CIFS never go "down". On 16.04 they were not a problem until more recently.  I have made sure to update every other day and have cleaned old linux headers (in hind sight i probably should have reverted). I do this because im begging for a fix to just appear but its been weeks of battling CIFS mounts without any solution.


Is there any documented evidence for suicide among vertebrates other than humans? Lemmings not accepted !


I answered a question and then deleted my answer. Now, I would like to find this deleted answer again. In similar posts (see , and ) it is claimed that the deleted answers appear in the list of all answers, perhaps at the end, perhaps marked red. I checked all my answers in all possible sortings but I cannot see my deleted question, neither red nor black. So, how can I find it?


A story about a guy who helped humanity by being held in a prison

I remember a story I have read buy could not remember the author the name or anything apart from the basic plot. The story is about some future where humanity has to fight with some aliens (not 100% sure). The story tells about a guy who was some kind of activist and who was in a prison two or more times and somehow helped humanity by being held in a prison (can't remember details). I think the story starts by saying that there is a statue in his honor that is not very well known but he did more to help humanity than famous politicians.   The story is most likely written by some famous English-speaking author, though I read it in a translation.


Is it possible to obtain a suspension on one's own user account by request?  If so, will the message on my profile make it clear that the suspension was requested, or will it look like I got in trouble?


Is it possible to start Ubuntu Desktop 18.04 always with Numlock on? In 16.04 it works with the file /usr/share/lightdm/lightdm.conf.d/99-numlockx.conf.


On connecting device - iTunes or iPhotos must not open

Whenever I connect my iPhone/iPad/iPod to MacMini, It automatically launches iTunes & start syncing every time. I am a developer & I frequently need to connect/disconnect different devices. So, whenever I connect device, I force quit iPhone & iTunes.   Can I eliminate the initial launch of iTunes and iPhoto when iOS devices connect over USB?


Valid email address using regular expression

I am new to PowerShell and I am stuck with a script to parse CSV document to identify if the emails are in proper format or not. My script does execute but instead of filtering records with invalid email it exports all records with the selected columns.  Please suggest as what I am missing.  $sourceFile = "d:\rvcc.csv" $targetFile = "d:\LMI-Invalid_Users_{0:yyyyMMMdd-HHmm}.csv" -f (Get-Date)  $validemailDomain1 = "^[a-z]+\.[a-z]+@stu.raritanval.edu$" $validemailDomain2 = "^[a-z]+@stu.raritanval.edu$" $validemailDomain3 = "^[a-z0-9]+@stu.raritanval.edu$" $blankemail=""  Import-CSV $sourceFile | % {     # The big blue bar:  Or Verbose text: Write-Verbose "Checking:         $($_.EmailAddress)"     Write-Progress -Activity "Checking user" -Status $_.EmailAddress     If ($_.EmailAddress -NotMatch $validemailDomain1 -or              $_.EmailAddress -NotMatch $validemailDomain2 -or             $_.EmailAddress -NotMatch $validemailDomain3 -or                 $_.EmailAddress -NotMatch $blankemail) {         $_ | Select-Object EmailAddress, FirstName, LastName, UserType, School_Id     } } | Export-CSV $targetFile -NoTypeInformation


Wormtail, while not the most faithful servant, was the person responsible for Lord Voldemort's resurrection, and possessor of a very cool hand. He was the one who allowed Harry's parents to be found and killed. Why then, after all that he did for Voldemort, was he cast as a mere servant?


Looking for my problem I've found an answer about completely empty interval:  that's clear. But what about this thing: [0,0) or [x,x) - an inclusive beginning and an exclusive end? Does it make x a part of this interval, or does the "exclusiveness" take it out? What is then taken as "higher", inclusiveness or exclusiveness? Does it make sense whatsoever?


As a non-native speaker I try to get myself to accept they as gender-neutral third person singular as this is new to me. To achieve this I would like to have a better understanding on the usage and history.  So when speaking in singular would I say 'they are' or 'they is' and respecively 'they sit' or 'they sits'. The second sounds strange but would be more logical as third person singular has this special case.  Or does this stem from the "pluralisation" (would honorific be the correct word?) of higher ups /royals that it is in fact a plural that is used for a "respected" person and was repurposed for the common use.  According to  it is "they are", and "they sit" accordingly.


Article awaiting reviewer invitation 6 months after submission

I submitted a paper to an internationally reputed journal. Two months after submission I was asked to suggest possible reviewers, which I did after a couple of days reflection. Since then it has been 4 months and the paper is still "awaiting reviewer invitation." I sent an email to the editor-in-chief as this was the only contact information given for queries. It has been almost two weeks without any reply. The day before yesterday I emailed the managing editor to know if the paper is under review or still awaiting reviewer invitation, but still I have received no reply from either editor.   How should I get in contact with the journal regarding my paper's review status?


Prove that a theory $\Gamma$ is consistent if and only if there is a structure $M$ so that $M$ $\models$ $\Gamma$.

$\Gamma$ is consistent, then either $\Gamma \models \varphi$ or $\Gamma \models \neg \varphi$ (but not both) for all sentences $\varphi$.  Can we assume $M$ is a structure such that $M \models \varphi$ for all $\varphi \in \Gamma$? I think this is incorrect because if so, $M \models \Gamma$ will be true trivially. We are assuming what we want to prove. If this is wrong, what else can I try?   On the other side, from $M \models \Gamma$, we have $M \models \varphi$ for every $\varphi \in \Gamma$.  Then can we say $M \not\models \neg\varphi$? And how can we finish the prove with $\neg (M \models \varphi \land \neg\varphi)$?


Let $R$ be a ring, $X,Y,Z$ and $T$ four $R-$ modules such that there exists a short exact sequence $$0 \rightarrow X \xrightarrow{f_1} Y \xrightarrow{f_2} Z \xrightarrow{f_3} T \rightarrow 0 $$  Prove the following:   (i)  If $X,Y$ and $T$ are Noetherian modules, then $Z$ is Noetherian.  (ii) If $X,Z$ and $T$ are Noetherian modules, then $Y$ is Noetherian.  I couldn't prove any of them, I assume both parts have similar proofs so I'll write what I've tried to do in (i) and I would appreciate some help with one of the two so I can complete the rest by myself.  In (i), there are alternative ways to show that $Z$ is Noetherian. I chose to show that every ascending chain is stationary.   So let $(Z_k)_{k \in \mathbb N}$ be an ascending chain in $Z$. Then $(f_3(Z_k))_{k \in \mathbb N}$ is an ascending chain in T. The same for $({f_2}^{-1}(Z_k))_{k \in \mathbb N}$ in Y. By hypothesis both of these chains are stationary. Let $N \in \mathbb N$ be such that $f_3(Z_n)=f_3(Z_N)$ for all $n \geq N$ and ${f_2}^{-1}(Z_n)={f_2}^{-1}(Z_N)$ for all $n \geq N$.  Take $x \in Z_n$ for $n \geq N$, I would like to show $x \in Z_N$. We have $f(x) \in f_3(Z_n)=f_3(Z_N)$, so there is $y \in Z_N$ such that $f_3(y)=f_3(x)$. But then $f_3(y-x)=0$, so $x-y \in Ker(f_3)=Im(f_2)$. Here I got stuck, there is $w \in Y$ such that $f_2(w)=x-y$, but in which submodule of $Y$ is $w$? And I don't see where to use that $X$ is also Noetherian. Any help would be greatly appreciated.


Allow anyone to comment but hide low-rep users' comments until reviewed

I've seen so many should-be-a-comment "edits" or "answers" in the review queues by new users, and it's pretty obvious that to them this was the only way to somehow interact with a question due to their lack of allowance to leave a comment. And sometimes (just sometimes) this comment would contribute something useful. So it's a shame to waste reviewers' time to first figure out that a suggested "edit" / "answer" should actually be a comment and then not exactly having tools to turn the former into an actual comment. If the new user would instead have had the possibility to clearly indicate that they wanted to leave a comment which would then be put into a simple "comments (by low-rep users)" review queue, where reviewers could maybe even leave one of the (more specific) automated comments à la "You should ask this as a new question" (where new question might even not only link to the "ask question" site but put the users comment into the title or body). And until approval the comment would by default by hidden by a "on hold" line that only higher-rep users, say >500, could toggle to view (and vote to approve directly in place). This is typical practice in many blogs' comments, and I think since we're community reviewing anyway this might be improve the hijacking situation. edit Note that by design those automated comments would not need to trigger a notification to the post's OP but only to the commenter. Whether the un-reviewed comment should already trigger a notification to the OP or not is a different question. I propose not, since the obvious once-in-a-while spam comment would be easier detected by a reviewer who is currently concentrating on specifically determining the validity of a comment. edit2 As noted in  these auto-replies should not clutter the original post - once a comment has been determined "Actually I want to ask a new question" they (and the reply) won't show up below the post except for the original commenter who will also be notified if they registered.  In summary:  Low-rep user posts a comment -> Below the post there will be a "1 comment under review" link and that comment will be added to the comment-review queue (see images below). No notification will be triggered for the OP, since the high likelihood of an unjustified comment was the reason for comments originally not being post-able by just anyone If a reviewer approves the comment, it will show up like any usual comment and now a notification to the OP (and @replied-to users) will be sent If a reviewer rejects the comment (with an optional reason as reply), it won't be shown below the original post as "under review" anymore. It, together with the reply, will be visible to the original commenter who will be notified, but no one else will be bothered by it edit3 As per : The commenter will not be able to post further comments until their comment is either reviewed or self-deleted. As , a negative review/flag should refute that user's ability to comment any more (or reduce a very low contingent of unreviewed comments allowed)


Firefox downloading torrents gives me no application to open them with - just opens download folder

When I download a torrent it asks me to choose an application to open it with but it shows none - even though I have deluge and qbittorrent installed. Clicking on "choose app" takes me to the download folder - no apps there.  Why are no apps recognised? And how do I find them?  Ubuntu 12.04 on Lenovo T500 with Firefox browser.


What is a Seaman's book, and can it really replace a passport?

What is a "Seaman's book", and can it really replace a passport for some or all immigration purposes?  Even Wikipedia the all-knowing does not seem to know, although it contains many tantalizing references.  :     Seaman deserters may not have a passport but rather hold a Seaman's Book, (a national identity document issued to professional seamen that contains a record of their rank and service career).   :     Possession of one of the following documents is sufficient to demonstrate [right to abode] ...         Hong Kong Seaman's Identity Book


Resistor in series needed with LED string?

I have an adjustable 24VDC power supply.  I have 1W LEDs that I was planning on stringing 7 or 8 in series to get approximately 24V across all of them together. They are rated 3.3-3.8V each. Do I need a resistor in series to maintain current? I was thinking so since a lit LED is basically a short? I can't find an answer to what it is really needed for, just that most people say to put a resistor in series to 'limit current'...  if so, it would be a small resistor, around 2 or 3 ohm?


A Proof of the Fundamental Theorem of Arithmetic

Is there a proof of the Fundamental Theorem of Arithemetic that does not make use of the Integers or Rational Numbers (as opposed to using only the Natural Numbers)? And if so, what is it?  By the Fundamental Theorem of Arithemetic, I mean that any natural number that is greater than 1 is a product of irreducible natural numbers and that this product is unique up to the order of multiplication.   The part that poses difficulty is proving is that if an irreducible number divides a product of two numbers, then it divides at least one of these numbers, which is used to show the uniqueness. Euclid makes use of rational numbers, and the only other proof that I have seen uses the lemma that if two natural numbers $n$ and $m$ are coprime, then there exists integers $l$ and $k$ such that $ln + km = 1$, which involves Integers rather than just Natural Numbers.


Vendors in my current game of Fallout 4 wont restock their items. I've been waiting for weeks for a mini nuke to be restocked.  Why don't they restock? Would it have anything to do with the mods I have installed?


As similarly described in a question   Let $\langle \mathcal{U}_n: n \in \mathbb{N} \rangle$ be a sequence of $\omega$-covers of $X$, and suppose that $X$ is . Can we always find a sequence $\langle F_n: n \in \mathbb{N} \rangle$ with each $F_n \in \mathcal{U}_n$ such that $\cup F_n$ is an open cover of $X$?  Thank you!  Note: The property that $X$ is Lindelöf was not an assumption in the referred question.


Sql Server equivalent of a COUNTIF aggregate function

I'm building a query with a GROUP BY clause that needs the ability to count records based only on a certain condition (e.g. count only records where a certain column value is equal to 1).  SELECT  UID,          COUNT(UID) AS TotalRecords,          SUM(ContractDollars) AS ContractDollars,         (COUNTIF(MyColumn, 1) / COUNT(UID) * 100) -- Get the average of all records that are 1 FROM    dbo.AD_CurrentView GROUP BY UID HAVING  SUM(ContractDollars) >= 500000   The COUNTIF() line obviously fails since there is no native SQL function called COUNTIF, but the idea here is to determine the percentage of all rows that have the value '1' for MyColumn.  Any thoughts on how to properly implement this in a MS SQL 2005 environment?


Energy consumption of the human brain: thinking vs not thinking

I'm wondering about the human brain's energy consumption at different "uses".  If you use a muscle it uses more energy than if you hold it still. Is the brain like this, or is it "always on" like a kidney or heart? Does it use more energy when you're actively learning or solving a problem? Do intelligent people have more energy hungry brains?  If I'm to sum into a single question, is the brain's energy consumption largely static (individually and over the population), or does it vary?      covers only the sleeping aspect and the top answer doesn't source is conclusion of static energy use. I'm still largely interested in differences while learning or problem solving and differences between intelligent and average people.


Cannot login after installing nvidia drivers. Gtx 1080. Limited 1024x768

Im new on ubuntu, when I installed the drivers, it got stuck at the end of "Applying changes", at a point I rebooted and when I tried to login, it looped, I putted my password, it seems it worked, but then it goes back to the login page. I am able to use CLI and login through CLI, I also tried to install the drivers through CLI but at the end an error came up, and when I rebooted the same happend, Im trying to install drivers because Im stuck at 1024x768 resolution, I cannot change that. How can I change the resolution/ install the drivers without loop?  Thanks.


Making cover page of a report; I want to put title below image

Below is my LaTeX code, I want it to continue the title under image, but, unfortunately, it continues to the next page and leaves a big space at the first page. How can I fix this.?      \documentclass{report}      \usepackage{amsmath}     \usepackage{amssymb}     \usepackage{graphicx}      \begin{document}      \begin{titlepage}     \includegraphics[scale=0.3]{upm.png}     \title{COMBINATORICS:- \\ Combination and Permutation in Statistics Application}     \maketitle     \end{center}     \end{titlepage}       \end{document}


What happens when you delete a Clustered index and Non Clustered Index once created

What happens when we dropped a Cluster index and Non Clustered Index once they are created?  What will happen to the data at the leaf level according to Clustered Index ?


pgfplots: Clipping Everything Outside a Specific Area

I want to add information to each column of a histogram. every node near coord is probably the best approach. It works well with bar plots but not with the histogram:  \documentclass{article}  \usepackage{pgfplots} \pgfplotsset{compat=newest} \usetikzlibrary{pgfplots.statistics}  \begin{document}  \begin{tikzpicture} \begin{axis}[ ybar interval, xticklabel=\pgfmathprintnumber\tick--\pgfmathprintnumber\nexttick, % Code to generate labels nodes near coords={ \pgfmathprintnumber{\pgfkeysvalueof{/data point/y}} }, every node near coord/.style={ anchor=south,xshift=9mm, }, % ] \addplot+[hist={bins=3}] table[row sep=\\,y index=0] { data\\ 1\\ 2\\ 1\\ 5\\ 4\\ 10\\ 7\\ 10\\ 9\\ 8\\ 9\\ 9\\ }; \end{axis} \end{tikzpicture}  \end{document}   I used every node near coord/.style to shift the labels.  The problem is that I have four labels for three columns/bars:    I addition I would like to center the labels. A workaround will be a manual adjustment (every node near coord/.style) just like in the shown example.  Update  Maybe clipping is a possibility. Is there a way to clip the labels (in this case the 7 in the right) away?  Like this:


How do I make an incomplete circle stroke for a donut chart?

I'm trying to emulate this type of stroke:    So far, I've only been able to pen over the stroke and try to Minus it off (though I'm a rookie and still don't understand the whole pathfinder tool completely), but it's tedious and I'm not that great at it.  Suggestions?


Problem to install Apache 2.4.2 in Ubuntu 12.04

I followed these steps to install Apache 2.4.2 in Ubuntu 12.04, but it seems Apache is not installed, here's what I did (I followed the steps on this site ):  sudo apt-get install build-essential sudo apt-get build-dep apache2 wget http://apache.mirrors.pair.com/httpd/httpd-2.4.2.tar.gz tar -xzvf httpd-2.4.2.tar.gz && cd httpd-2.4.2 sudo ./configure --prefix=/usr/local/apache2 --enable-mods-shared=all --enable-deflate --enable-proxy --enable-proxy-balancer --enable-proxy-http --with-mpm=prefork sudo make sudo make install   when I tried to start by issuing sudo /usr/local/apache2/bin/apachectl start at terminal, I got the following warning:   AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message" and when I typed **top** at terminal, the apache is not there. I also tried to go to http://localhost/ or 127.0.0.1 or even 127.0.1.1 it showed "Can't establish connection to server ..." message.    P.S.: I checked the error log and it showed  [Fri Jul 27 15:49:00.703901 2012] [proxy_balancer:emerg] [pid 20781] AH01177: Failed to lookup provider 'shm' for 'slotmem': is mod_slotmem_shm loaded?? [Fri Jul 27 15:49:00.704083 2012] [:emerg] [pid 20781] AH00020: Configuration Failed, exiting   What am I missing?


Is using "someone" in a question correct?

When reading about  on the OALD, I saw the following note:     The difference between someone and anyone is the same as the difference between  and . Look at the notes there.   The note that I read for some is the following:     In negative sentences and questions any is usually used instead of some:           I don't want any more vegetables.     Is there any wine left?           However, some is used in questions that expect a positive reply:           Would you like some milk in your coffee?     Didn't you borrow some books of mine?      Does that apply to someone too? Should I use someone in a question when I am expecting a positive answer?      Does someone know the answer?


How can I allow a filter in a view to be modified by a site admin without granting full permission to alter the view?

I have a module with a view and some other functionality. I want to give site managers the ability to change the filter on the view (this isn't an exposed filter) but not give access to change the view.  I know how to make a form for the module but what would I use to get the information from the view and return the information.  I assume it is one of these:


What's a word for someone who does what they say?

I'm looking for a single word that means something like 'being a man/woman of your word', or 'follow through' as a noun. I tried using 'integrity' at first, but that has other implications, like honesty and other moral principles.


In which table is saved the original publish date for each post?

I often modify the publish date, but I keep every revision.  Where can I find when the post was published for the first time?


Android - Why the string returned by getResources().getStringArray cannot be used in if clause?

My arrays.xml:  <string-array name="chart_names">         <item>abc</item> </string-array>   My testing code:  String[] chartNames = getActivity().getResources().getStringArray(R.array.chart_names);  if ("abc" == chartNames[0]) {   Log.v("msg", "yes"); }else{   Log.v("msg", "no"); }   I always get false, so the console always prints "no".  Why does this happened ? It's really strange.....  Please help me....... Thanks.


Why does it keep saying "Housing Invalid" for the room on the left?

How do I get the room on the left to be a valid house for an NPC?


Computing float to 2 digits only (not formatting/rounding off 6 digits after decimal to 2)

I am running a computation on an embedded processor which involves a float operation like this:   a = (float)23 / (float)3;  // a = 7.666....7   This is a long computation, and my app is OK with a certain amount of rounding error; I mean 7.67 or 7.66 doesn't matter.  Is there a way to cut down the amount of computation time spent in computing the float, or telling math.h to 2 digits ?  Any idea how to do this ?  PS:  Now I know many will suggest using fixed point, but I have specific requirements.


My steampunker won't spawn even with all of the requirements fulfilled?

I can't make the steam punker move into my house! Even though i killed a mechanical boss, removed the Hallow from my house, and the house is suitable, she isn't moving in. Could someone please help me? I just don't know what went wrong!


For $\alpha = \sqrt{2+\sqrt{2}}$, what is ${\rm Gal}(\mathbb{Q}(\alpha)/\mathbb{Q}$?

So $\alpha = \sqrt{2+\sqrt{2}}$, and I've already found the minimal polynomial of $\alpha$ over $\mathbb{Q}$ to be $p=x^4 - 4x^2 + 2$ and shown that $\mathbb{Q}(\alpha)$ is a normal extension. Now I want to describe the Galois group. We know $[\mathbb{Q}(\alpha) : \mathbb{Q}] = 4$, so the Galois group has $4$ elements. The basis of the extension is $\{1, \alpha, \alpha^2, \alpha^3\}$, so the automorphism of $\mathbb{Q}(\alpha)$ leaving $\mathbb{Q}$ fixed need to act on $\sqrt{2}$ and $\sqrt{2+\sqrt{2}}$, I think. These would be: \begin{align*} \sigma_1 &: \sqrt{2}\rightarrow\sqrt{2}, \: \sqrt{2+\sqrt{2}} \rightarrow \sqrt{2+\sqrt{2}} \\ \sigma_2 &: \sqrt{2}\rightarrow -\sqrt{2}, \: \sqrt{2+\sqrt{2}} \rightarrow \sqrt{2+\sqrt{2}} \\ \sigma_3 &: \sqrt{2}\rightarrow\sqrt{2}, \: \sqrt{2+\sqrt{2}} \rightarrow -\sqrt{2+\sqrt{2}} \\ \sigma_4 &: \sqrt{2}\rightarrow -\sqrt{2}, \: \sqrt{2+\sqrt{2}} \rightarrow -\sqrt{2+\sqrt{2}}  \end{align*}  Since all of these automorphisms are of order $2$, the Galois group of the extension is isomorphic to $\mathbb{Z}_2 \times \mathbb{Z}_2$  Is it correct? Could the argument be simpler?


Using a USB-C dock with older MacBook Pros

Thunderbolt 2 docks have been quite expensive and they will be obsolete once I purchase the new Macbooks with USB-C ports. I currently use a 2014 MacBook Pro with Thunderbolt 2 ports, and I want to futureproof my purchase by acquiring a cheaper USB-C dock now.  The cheapest Thunderbolt 2 dock costs around $200 while USB-C docks cost around $30. Being able to use a USB-C dock with older Thunderbolt 2 Macbook Pros would not only be cheaper but also allows me to use the same USB-C dock if I decided to upgrade to a future Macbook.  For that to work I need a Thunderbolt 2 (male) to USB-C female adaptor, after some searching it doesn't seem to exist. Is there a reason why something like this hasn't been made? Or is the USB-C specification designed such that it is impossible? (hence businesses can still continue to sell expensive Thunderbolt 2 docks...)  I will accept an answer that meets the following requirements:   If there is such an adapter please give a link and some form of evidence that these would have 100% compatibility with USB-C docks. If there is no such adapter please explain:   Is it impossible to produce? If not, why hasn't a vendor created one yet? I've explained that its a better financial investment than buying a TB2 dock... surely there's a market for those still using TB2 MBPs wanting to upgrade in the next couple of years. Not only docks but it would open a gateway to cheaper alternatives to those hideously expensive TB2 peripherals.


ES6 Object.forOwn loop over object keys functionality

Disclaimer: I'm aware there are  , but none convinced me it was the final solution.    I'm very surprised to find out there doesn't seem to be a standard way to functionally loop over an object.  Lodash has .  The ES6 way seems to be:   Object.keys(object).forEach(key => { console.log(key, object[key]); });  but this is not functional since object is external of the iterator function.  I haven't even found any polyfill.  for ... in doesn't even seem like a solution to me.  How do you guys write this?


Connect to Wi-Fi with minimal installation of Centos

I've just installed CentOS 8 on my laptop using the minimal ISO.  While it was able to connect to my apartment's Wi-Fi during installation, I am unable to get any connectivity from the terminal. uname -a prints Linux localhost.localdomain 4.18.0-193.el8.x86_64 #1 SMP Fri May 8 10:59:10 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux  lspci prints ... 01:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter ...  rfkill prints ID TYPE      DEVICE                 SOFT      HARD 0  wlan      ideapad_wlan      unblocked unblocked 1  bluetooth ideapad_bluetooth   blocked unblocked 2  bluetooth hci0                blocked unblocked 3  wlan      phy0              unblocked unblocked  ip l prints 1. lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2. enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000     link/ether c8:5b:76:c4:da:b2 brd ff:ff:ff:ff:ff 3. wlp1s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000     link/ether c8:3d:d4:7e:8f:ed brd ff:ff:ff:ff:ff:ff  nmcli radio all prints WIFI-HW  WIFI     WWAN-HW  WWAN enabled  enabled  enabled  enabled  nmcli device status prints DEVICE  TYPE      STATE      CONNECTION enp2s0  ethernet  connected  enp2s0 lo      loopback  unmanaged  -- wlp1s0  wifi      unmanaged  --  ping 192.168.1.1 prints connect: Network is unreachable  I'm connected to my router over the LAN so I'm able to install any packages as needed. Also, nmtui, while it allows me to edit my Wi-Fi connection, does not allow me to activate said connection.  That is, the connection doesn't show up under "Activate a connection".


Does Calculate Value run only once in Batch mode?

I wrote a model with a model-only tool (Calculate Value) as the first step. While running the model in single time, it works fine. But while run in batch mode, it yields silly results. I checked the log (messages) of the batch processing and found that the Calculate Value ran only once while the rest of the model run multiple times. I confirmed Calculate Value running only once is the cause of the silly results. Does this mean the model-only tool (Calculate Value) can only run once in batch mode? Is there any way to fix it?


How can I use a 12 V input on a digital Arduino pin?

I am creating a controller for a 12 V system using an Arduino Uno microcrontroller. For the outputs I am using a relay shield to switch the 12 V components. I have a 12 V toggle switch that turns on some 12 V components in the system and I want to use a trigger signal off of this same switch to send to an Arduino digital input. I know that the Arduino can only handle 5 V max. What would be the best way to step down the 12 V coming off of the switch to the 5 V for the input?  EDIT: The system is for use in a car. Would the amperage of the car battery need to be lowered somehow as to not blow up the components?


Why is the front brake lever on the right if you 'drive' on the left and vice-versa?

I live in the UK and I expect my front brake lever to be operated by my right hand. However, I recently went on a friend's bike that had the brakes 'back to front', which would be the 'right way round' for people in Europe, North America and everywhere else that drives on the right.  I am left-handed and therefore used to finding things designed to be best operated with the right-hand, e.g. the controls on a lawnmower.  What are the reasons for the brake lever convention on a bicycle? It seems that the front brake is more important for controlled braking, in the UK we have that worked by the right hand, which makes sense. For countries that drive on the right that means the back brake has the 'handed-ness' advantage, rather than the front.  I also like to be controlling my speed with the front-brake when making a right-hand turn, however it is not possible to do this when signalling. A left turn is not so important to stick your arm out for - drivers coming the other way and behind don't really care if the sign is not made for a left-hand turn, whereas a right-hand turn really should be indicated. So, from that perspective, the brakes are the 'wrong-way-round' for me.  Can someone kindly guide me through why the brakes are wired up so and any historical origins of the convention?


Java, why is toLowerCase() not working in if condition, only print?

I am Java beginner. I dont understand why .toLowerCase() is not working when placed in if condition. A simple version of my code: if ( recType.toLowerCase() == "device") {           System.out.println("done");       }  it works when recType= "device" ofcourse but when recType="Device", it doesnt convert it to "device" so whats inside the if condition is not implemented!!. Any ideas?


Why use some_string[-1:] instead of some_string[-1]?

foo = 'eggs'  foo[:1] # the same is foo[0] foo[-1:] # the same is foo[-1]   Is there any advantage of one of these ways?  I ran into this over here   UPD. Can you go to the link? The variable path is a string there. And I was confused, why they were using a slice instead of a concreate index.  if path[-1:] == "/":


How to prove infinite product converging to sin and cos?

How to prove following statements in the simplest way: $$ \sin(x)=x\prod\limits_{n = 1}^{\infty}\Big(1-\frac{x^2}{\pi^2n^2}\Big),\quad \cos(x)=\prod\limits_{n = 1}^{\infty}\Big(1-\frac{4x^2}{\pi^2(2n-1)^2}\Big). $$ We are learning infinite products, but the teacher just gave it to us without proof. I`ve read  and that material is too hard to understand(i mean Weierstrass factorization theorem, as proof follows from it). Is there any simpler way?


i'm trying to install putty and i got the following error   E: Malformed entry 4 in list file /etc/apt/sources.list.d/additional-repositories.list (Component) E: The list of sources could not be read. E: Malformed entry 4 in list file /etc/apt/sources.list.d/additional-repositories.list (Component) E: The list of sources could not be read.   after going through some posts on this forum . i opened the file using sudo nano /etc/apt/sources.list.d/additional-repositories.list i have the following content  deb [arch=amd64] https://download.docker.com/linux/debian    sylvia    stable deb [arch=amd64] https://download.docker.com/linux/debian    sylvia    stable deb [arch=amd64] https://download.docker.com/linux/ubuntu    sylvia sudo add-ap$ deb [arch=amd64] https://download.docker.com/linux/ubuntustable deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable   i created a space between ubuntu and stable in line 4 . but still got the sane error? what is wrong with it ?  P.S:- While getting my hands on first time on docker, i uninstalled some packages which i don't need . so, i would like to remove all docker files and install freshly for linux mint.


How to extract distribution information from descriptive statistics?

In my thesis, I am trying to perform a Monte Carlo simulation with a set of parameters, where I take a random value from a known distribution to calculate a singe run of the simulation.  However, for several parameters of the analysis, I was not given the sample data, but only this information:           vars    n       mean    sd      median  trimmed mad     min     max         skew    kurtosis    se DATA    3       176999  49,04   71,67   26,12   36,03   11,28   0,02    2411,33     8,21    98,56       0,17   From what I was told, this is a set of descriptive values of the sample that was obtained through psych R package.  The problem is that I don't know anything else about this data. From what I researched, there are methods (implemented in MATLAB, which I am using) to obtain a random sample from these data such as Pearson and Johnson Systems.   My idea was to use these random data to generate a PDF, and from there get random values for the MC simul.  I ran the pearsrnd MATLAB function with the data, and for some parameters I got some results associated with the Gamma function, but for others only obtained NaNs.  My question is, how can I extract more info from these small info I was given, which methods to use for that.  Note that my knowledge of probabilities and statistics is very very limited, I am only getting used to these concepts right now.


I'm a java beginner and I'm reading First head Java book. I did manage what the book asks for, but I'm trying to improve the program  the program is supposed to generate a random number between 0-7, then put it an an array with the following two number and the user has to guess it. everything is working except that I'm trying to restrict the user from entering anything but numbers from 0 to 7  here is my try, and I don't know why it's not working:  public String  checkYourSelf (String stringGuess){     String result = "miss"; //this will be returned if the guess doesn't match     if (stringGuess != "0" ||         stringGuess != "1" ||         stringGuess != "2" ||         stringGuess != "3" ||         stringGuess != "4" ||         stringGuess != "5" ||         stringGuess != "6" ||         stringGuess != "7" ){             System.out.println("Please Enter a correct number");             result = "error";             return result;         }    and after this I use the parseInt method  int guess = Integer.parseInt(stringGuess);   the whole method :       public String  checkYourSelf (String stringGuess){     String result = "miss"; // this will be returned if the guess doesn't match     if (stringGuess != "0" ||         stringGuess != "1" ||         stringGuess != "2" ||         stringGuess != "3" ||         stringGuess != "4" ||         stringGuess != "5" ||         stringGuess != "6" ||         stringGuess != "7" ){             System.out.println("Please Enter a correct number");             result = "error";             return result;         }      int guess = Integer.parseInt(stringGuess);      for (int cell : cellsLocations) {         if (enterdNums.contains(guess)){             result = "error";             System.out.println ("You've entered this number already.");             System.out.println("Please try again");             break;         }         if (cell == guess) {             result = "hit";             hits++;                   break;         }     }     if (hits == cellsLocations.length) {         result = "kill";      }     if (result != "error"){          System.out.println(result);     }     enterdNums.add(guess); // add to the list so it doesnt     return result;    }     }   in the main method :  while (isAlive) {         guess = input.getUserInput("Enter a number");         result = dot.checkYourSelf(guess);         if (result == "error"){             continue;             }          numOfGuesses++;          if (result == "kill"){             System.out.println(numOfGuesses);             isAlive = false;             break;         }      }   I know there might be other ways to do this, but I'm trying to do it from stuff I know already, and logically this should be working, however if I enter any number it will say "Please enter a correct number"  thanks


Apologies in advance for the Eevee question... but!...now that the releases are getting more stable, I'm messing around with it and wondering if anyone has gotten an alpha channel/transparency mix shader to work with it.   Usual setup doesn't seem to work. It looks liek there was a transparency socket at some point, but not now, and plugging the alpha into the transmission does nothing.


What are the relative strengths of TikZ and Asymptote?

I want to compare TikZ and Asymptote for their abilities in 2D & 3D functional plot and other general purpose, simple drawings.   What are the strong aspects of TikZ over Asymptote?


Guest book does not appear to be saving data?

The new Guest Book seems like a nice idea, but it doesn't appear to be saving any data entered into it. Entered text appears immediately upon submitting the form on the current page via JavaScript, but the data does not seem to be posting anywhere and does not survive a page reload.  There's a new JavaScript object called XMLHttpRequest (now standard with Internet Explorer 5) which might allow us to post the form data asynchronously without the need for reloading the entire page, but I haven't had a chance to experiment with it yet.  Maybe the devs can look into it?


Outdated Answers project kicking off on Stack Overflow

As we , we are kicking off a project to begin tackling the issue of outdated answers. That post goes into detail on the initiative and our approach. We are focusing our initial research efforts on Stack Overflow, and not on other sites on the Stack Exchange network. We understand that the issue with outdated answers is not exclusive to Stack Overflow and other technical sites may have similar issues. However, none of the other sites operate at the scale of Stack Overflow:  more than 31 million answers, compared to 11 million for the rest of the network. And Stack Overflow is our oldest site, so it is the site where the pain is most acute. Rather than trying to shoot for a one-size-fits-all solution that may actually fit none, we are laser-focused on uncovering the Stack Overflow use cases and coming up with initial solutions that work really well for Stack Overflow.  We are optimistic that many of the learnings from Stack Overflow will also be relevant and helpful for similar issues faced by other sites on the network. As we get further down the road, we will evaluate whether the Stack Overflow solution can also work for other sites and solicit your feedback here on Meta Stack Exchange. With this in mind, feel free to share any initial thoughts on how you've experienced outdated answers on other Stack Exchange sites and any ideas you have about ways to attack this problem.


Calculate probability (area) under the overlapping area of two normal distributions

I have two normal distributions defined by their averages and standard deviations.  Sample 1: Mean=5.28; SD=0.91  Sample 2: Mean=8.45; SD=1.36  You can see how they look like in the next image:    How can I get the probability to obtain an individual from the overlapping area (green)? Is the probability the same as the area?


Suppose I begin with the following list [a,b,c], and that I from this list want to create the following list [[a,b,c], [c,a,b], [b,c,a]]which contains all the cycles of the original list. How can I do that in the most efficient way possible?


Installing Ubuntu on Dell Inspiron 8600: no operating system found when trying to boot from USB

We have an old Dell Inspiron 8600 laptop that had an OS/hard drive crash a year or so ago. Destroyed the hard drive and was going to send the laptop off for recycling but never did. 2 weeks ago I had the idea to buy a new/refurb'd hard drive and install Ubuntu so we could use the device for basic tasks. Bought/installed a refurbished 60 GB hard drive. System specs: Dell Inspiron 8600 laptop w/ a Pentium M 1.60 GB/600 MHz processor, 1024 Level 2 cache, 1024 MB @ 333 MHz Memory, NVIDIA GeForceFX5200 Video Controller w/64 MB Video Memory. (OK, I know this is old stuff!) Downloaded the lubuntu-16.04-desktop-i386.iso file and put that on a USB stick.  Went into the boot menu and selected the USB drive for the new (blank) hard drive to boot from. When I try to boot, I am getting the message:  An operating system wasn't found, Try disconnecting any drives that don't contain an operating system. Press any key to restart.  Two questions:  Did I select the the appropriate "flavor" of Ubuntu for this (older) machine, and if not - which version would work best?  Please tell me what I'm doing wrong - and hopefully you can provide some (detailed) instructions on how to make this happen.


Why creating an anonymous Runnable subclass for Threads?

When working with Threads, it is fairly common to write something like this:  Runnable r = new Runnable() {     public void run() { /* ... */ } }; new Thread(r).start();   This is all nice and correct, but I believe the same could be achieved in a more performant and easy way:  new Thread() {     public void run() { /* ... */ } }.start();   However, I almost never see anything like this in code examples using Threads and Runnable. Is there any technical or style-related reason to use the first example instead of the second?


Some taskbar pinned icons are duplicated when an instance of the application is running

For some applications that I pin to the taskbar, the icon gets duplicated when an instance of the application is running.    For example, in the screen shot below you see there are two icons for VMWare Player (icons all the way to the right).  The first (left) icon for VMWare Player is the one I pinned to the task bar. The second one (right) is linked to the running instance of VMWare Player.    If I start another instance, then gets grouped with the second icon. For most other programs (like Google Chrome in the screen shot below) the running instances just get grouped with the original pinned icon.    Can I make VMWare Player behave the same way? Why does it behave differently anyway?


Please help me, I have no idea why this MWE does not work. I am using the TeXnicCenter. I get the error message: Citation 'author2000' on page 1 undefined on input line 29. \listfiles                % shows used packages in a list in log file \RequirePackage{filecontents} \begin{filecontents*}{\jobname.bib} @article{author2000,   author  = {AuthorA},   title   = {Title of Article},   journal = {Name of Journal},   year    = {2000}, } \end{filecontents*}  \documentclass{article}  \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage[german]{babel} \usepackage{csquotes}  \usepackage[%   style=authoryear  ,backend=biber         % to force biblatex to use biber  ,sortlocale=de_DE ]{biblatex} \addbibresource{\jobname.bib}  \begin{document}  hi.\autocite{author2000}      \nocite{*}              % all bib entrys are printed  \printbibliography  \end{document}  geh.blg just says  [0] Config.pm:320> INFO - This is Biber 1.9 [0] Config.pm:323> INFO - Logfile is 'geh.blg'


Are orcs considered evil to Eru and the Valar?

It's to my understanding that orcs were once elves that were captured and tortured by Morgoth ages ago, becoming what's now orcs. Being captured and tortured is obviously not their fault, therefore are they considered evil by Eru and the Valar? Will they be treated differently compared to men and elves when they die?


Why does a ballerina speed up when she pulls in her arms?

My friend thinks it's because she has less air resistance but I'm not sure.


How would I create new edges around an opening

What method would you use to create new edges around this doorway maintaining it's shape? (desired outcome in red)


Inconsistent search behaviour with words equaling tag names

I just typed food into the search box at  and this gives me search results containing the word food. The search query is https://opendata.stackexchange.com/search?q=food. [food] .  Same when searching for sleep at : the query is https://productivity.stackexchange.com/search?q=sleep.  But I recently noticed* at other SE sites that if you enter a word that is also a tag name, this initiates a search for the tags:  Search for 'delphi' at  performs https://stackoverflow.com/questions/tagged/delphi Search for 'professionalism' at  performs https://workplace.stackexchange.com/questions/tagged/professionalism  Why this inconsistent behavior? Or is this 'consistent' one way for beta sites and the other way for non-beta?  * At the time I considered this unwanted behaviour—if I want a tag, I'll search for [tag]—but that is another issue, partially adressed .


Java, new to java and my code won't work be seems to be fine (no errors)

package question; import java.util.Scanner; public class quiz {     public static int score = 0;     public static void main(String args[]){-         Scanner inp123 = new Scanner(System.in);          String q1;  System.out.println("whats my name?");         q1 = inp123.nextLine();         if (q1=="matt"){             System.out.print("Correct that is my name!");         }else{             System.out.println("Incorrect");             score = score + 1;             System.out.print("Your score is: ");             System.out.println(score);             quiz.main(args);         }   Heres my code and when I input matt it says its incorrect new to java, if anyone can help me or be willing to teach me java reply or hit up my inbox, I have good experience in python and looking for a new language


Is there a way to add a function in an SP app that informs you when someone adds a new item in a list?

I have an app that is connected to a list and I want to put a function in it that informs me when someone adds a new item in the list, it could be an alert message or something like that. Any ides?


Why does the blackbody radiate even at thermal equilibrium?

Everytime, I read about blackbody, I always get confused at the point where it is written     Under thermal equilibrium conditions , the blackbody radiation depends only on temperature. ..... . At equilibrium , electromagnetic waves bounce around with the walls of the cavity.   What is this equilibrium all about? Why is it important here?? If there is thermal equilibrium, why does the body radiate?? Please help.


How do I add an icon to an executable file

I have several utility programs that I can run only by clicking on their "generic" executable file. How can I assign an icon to each of them for it to show in the Launcher? I am using Ubuntu 14.04 LTS. Thanks.


FFMPEG add audio to a video but clip it to the video length

I'm trying to create a video from an image sequence and add audio with FFMPEG  The frame sequence is only 25 frames long but the audio is several minutes. I want FFMPEG to clip the audio to the length of the frame sequence.  This is the command I have tried:  ffmpeg -i input_images%04d.jpg -pix_fmt yuv420p -vcodec mjpeg -qmin 1 -qmax 1 -r 25 -i audio_file.mp3 -ar 22050 -ab 192k -aframes 25 output.mov   This results in a video with the first image sequence but the full length audio. -aframes is ignored. Any ideas?


If $(X, \mathcal{T})$ has a countable subbasis, then it has a countable basis

Given $(X, \mathcal{T})$ a topological space. Let $\mathcal{S}$ be a subbasis on $(X, \mathcal{T})$     Claim: If $\mathcal{S}$ is countable, then $\mathcal{T}$ has a   countable basis $\mathcal{B}$   I am not sure how to go about approaching this quetion but here's my attempt:  I want to show that there exists a surjection $g$ from $\mathcal{S}$ to $\mathcal{B}$, and there is an injection $f$ from $\mathcal{B}$ and $\mathcal{S}$ thus $|\mathcal{S}| = \aleph_0 = |\mathcal{B}|$  Define $g$ as  $$g(S_1, S_2, \ldots, S_n) = S_1 \cap S_2 \cap \ldots \cap S_n = B$$  where $S_1, \ldots, S_n \in \mathcal{S}$, and $B \in \mathcal{B}$  But how does the countability of $\mathcal{S}$ come in? I'm really lost    Per Henno's suggestion re-attempt:   Let $\mathcal{S}$ be a countable subbase of $(X, \mathcal{T})$. Then $\mathcal{S}$ can be listed as $\{S_1, S_2, \ldots \}, S_i \in S, i    \in \mathbb{N}$   By definition, each basis element is the finite intersection of subbasic elements written as $\bigcap\limits_{i \in F_n} S_i$, where $F_n$ is a finite set in $\mathbb{N}$.   Since there exists countably many finite sets in $\mathbb{N}$, we can list all the finite sets as $\{F_1, F_2, \ldots\}$   Then correspondingly we can list all the basis elements as:$\{\bigcap\limits_{i \in F_1} S_i, \bigcap\limits_{i \in F_2} S_i,    \ldots\}$ which is a countable set.    Hence $\mathcal{B}$ is countable.


Dark gray section in the viewport that can't be changed?

What is this long dark section? I'm not sure what I did to make it appear but it prevents me from seeing other objects in my scene. I tried adjusting the clipping already but it did not seem to help.


Harry potter normal curriculum education

The wizards learn magic at Hogwarts, but what about "normal" education. Muggles learn English, Math etc. Is this not noticed when they make contact with muggles that they can't do basic math that you learn from age 11 and up. Do Hogwarts teach the kids things that are in the normal curriculum for those ages, or is it something that they do on their spare time? Or is this something that is considered irrelevant for wizards?


What is the proper way to explain the twin paradox?

The paradox in the  is that the situation appears symmetrical so each twin should think the other has aged less, which is of course impossible.  There are a thousand explanations out there for why this doesn't happen, but they all end up saying something vague like it's because one twin is accelerating or you need general relativity to understand it.  Please will someone give a simple and definitive explanation for why both twins agree on which twin is younger when they meet for the second time?


openvpn: auth-user-pass or (and?) passphrase?

I'm setting up OpenVPN on PfSense 2.0, and now i wonder if should use the "auth-user-pass" option, set an passphrase on the openssl keys or both.  Both require an extra password beside of the valid certificat, but i don't know if one method is more secure than the other.  It seems that only the "auth-user-pass" method is directly supported in the PfSense web-interface, so that using a passhrase would mean an extra step (adding the passphrase with the openssl command) for each certificate.


I got this array:  Array (     [0] => Array         (             [_complex] => 1             [_attributes] => Array                 (                     [id] => 453                 )              [_data] => Array                 (                     [id] => 453                     [nid] => lastname                  )          )    [1] => Array         (             [_complex] => 1             [_attributes] => Array                 (                     [id] => 455                 )              [_data] => Array                 (                     [id] => 455                     [nid] => lastname                  )          )   How to sort it by [_data][nid]?


Could a Time Lord/Lady recognise other Time Lord/Lady independent from their regenerations? Like when The Doctor “recognise” the  in "The end of time" or when The Doctor recognise The Master in "Utopia"?  The Master also avoided to see the Doctor before the Doctor timeline reaches the point where the Master already have stolen the TARDIS.


I'm not sure of the right place to ask this, but I got confused trying to understand how the computer will interpret the sentence:     This is my picture.   In actual sense, the real owner of the picture should be the photographer not the person who was photographed... or am I getting something wrong? So, it seems the confusing thing about 'picture' is determining who the real owner of the picture is. So is there a special category for these kind of nouns or an official clarification somewhere?  Thanks


how to increase ubuntu's performance(overall)

I have a 1Tb hdd(internal in laptop) which I have divided in 750Gb (windows partition) and 100Gb ubuntu partition , my ubuntu OS is quite dull(over all performance including boot and multitasking) after 2 updates from 14.04 to 14.04 and 14.10 to 15.04. Now my main question is Should I reinstall by formatting and repartitioning drive giving 1Tb space to ubuntu entirely, since I want to use only ubuntu operating system. If no then how should I increase my system performance with ubuntu (and I seriously want to get rid of windows).  PS: (other hardware configuartion) Samsung Laptop with 6Gb ram and Quad core (4 * 2.5Ghz Intel i5 processor) Windows 7 Home Premium Preloaded with other recovery software's  (which might affect system performance).


Using the universal property of tensor product to show that $(\Bbb{Z}/4\Bbb{Z}) \otimes (\Bbb{Z}/6\Bbb{Z})\cong \Bbb{Z}/2\Bbb{Z}$

In the algebra lecture i need to solve the following exercise     Use the universal property of the tensor product to show that    $$(\Bbb{Z}/4\Bbb{Z}) \otimes (\Bbb{Z}/6\Bbb{Z})\cong \Bbb{Z}/2\Bbb{Z}$$   Here is my job:  I tried to follow the example seen in the lecture where we showed that $(\Bbb{Z}/2\Bbb{Z}) \otimes (\Bbb{Z}/3\Bbb{Z})=0$. In that example the professor listed all the generators of $(\Bbb{Z}/2\Bbb{Z}) \otimes (\Bbb{Z}/3\Bbb{Z})$ and then showed that every generator is actually zero just by using the properties of the tensors. Namely  $$\begin{array}{|cc|}\hline 0\otimes n = 0\otimes n + 0\otimes n &\implies 0\otimes n =0 \\\hline 1\otimes0=1\otimes 0 + 1 \otimes 0 &\implies 1\otimes 0 =0 \\\hline 1\otimes 2 =2(1\otimes 1) = 0\otimes1&\implies1\otimes 2=0 \\\hline 1\otimes1 =1\otimes 4 = 1\otimes2 + 1\otimes 2 & \implies 1\otimes 1 =0\\\hline \end{array}$$  for $n= 0,1,2$.  Now to show that $(\Bbb{Z}/4\Bbb{Z}) \otimes (\Bbb{Z}/6\Bbb{Z})\cong \Bbb{Z}/2\Bbb{Z}$ I tried to list all the generator and try to show that they are equal to $0$ or $1$. We have $4\cdot 6=24$ generators and i noticed that if a generator has a even integer than it is equal $0$. The problem is that i can not show that some generators are equal $1$. Indeed the generators equal $0$ are  $$\begin{array}{|cc|}\hline 0\otimes n=0\otimes n + 0\otimes n& \implies 0\otimes n =0 \,\,\,n\in \{0,1,2,3,4,5\} \\\hline n\otimes 0 = n\otimes 0 + n \otimes 0&\implies n \otimes 0 =0 \,\,\, n \in \{0,1,2,3\}\\\hline  \end{array}$$  and  \begin{align*} 1\otimes 2=0 && 1\otimes 4=0 && 1\otimes 6=0 \\ 2\otimes n=0 && 3\otimes 2=0 && 3\otimes 4=0 \\ 3\otimes 6=0 \end{align*} for $n \in \{0,1,2,3,4,5\}$  The other generator can be brought back at the case $1\otimes 1$ and therefore i wish i could show $1\otimes 1$ can be considered as $1$, but i'm not able to. I know that i should use the universal property of the tensor product but i don't really know how to use it, therefore i think that there must be another procedure to solve the exercise. Is what i've done so far correct?


How close I am to getting Inquisitive badge?

I was checking my user profile on stack exchange and found this feature very useful (3/5 says almost whole story).     But this feature is not yet available on stack overflow website. And I hope it will take sometime before integration of these set of features with stack overflow.  Till then, is there any way I can get to know, how close I am to getting Inquisitive badge on stack overflow?


Here's the problem: (This problem is from Hungerford's Algebra Chapter 5 exercise 6.7 )  Let R be a principal ideal domain and $p$ a prime in $R$ and $n$ a positive integer. Then $R/(p^{n})$ is an unitary $R/(p^{n})$-module with $(r+(p^{n}))(s+(p^{n}))=rs+(p^{n})$. I attempt to demonstrate that the $R/(p^{n})$-module $R/(p^{n})$ is injective as following steps:  (1) I notice that the ring $R/(p^{n})$ is a principal ideal ring since it is a quotient ring of $R$ which is a PID. And by this fact, I prove that each proper ideal of $R/(p^{n})$ is generated by $p^{i}+(p^{n})$ with $0<i<n$.  (2) Now, in order to prove that module $R/(p^{n})$ is injective, it is sufficient to prove that for each ideal $I=(p^{i}+(p^{n}))$ of the ring $R/(p^{n})$ the module homomorphism $f: I\rightarrow R/(p^{n})$ can be extended to a homomorphism $R/(p^{n})\rightarrow R/(p^{n})$.  The module $R/(p^{n})$ is injective? how to extend this module homomorphism $f: I\rightarrow R/(p^{n})$? Anyway, any and all help is appreciated. Thanks.


Area common to 3 parabolae inscribed in a triangle

Suppose you a have triangle ABC of sides 15, 13 and 4. Three parabolae are drawn such that each parabola is tangent to two side of the triangle such that the third side is a chord of the parabola, which means the two tangents touch the parabola at the vertices of the triangle. Find the area common to the 3 parabolae. I am a high school student and my maths teacher just asked this question in class. He then told us to not waste our time on it as it is way beyond our level but this keeps bugging me. I have only studied coordinate geometry(algebraic) so I have very little experience in pure geometry of parabola. I tried to find some symmetry in the question like 5,12,13 and 9,12,15 are pythagorean triplets. I know of a formula which describes the locus of a point from which tangents subtend a particular angle to the parabola which I tried applying as I know all of the angels of the triangle but it was very tedious. I thought maybe the chords are focal chords but I realised tangents at ends of focal chord subtend right angles, so that's also not possible. In the end none of attempts yielded anything fruitful. So how to solve this problem? Is there an elegant solution without any messy algebraic calculations? Bonus points for book suggestions having these type of tough problems within the high school curriculum.


What's the idea of lane swapping in LCS?

In worlds, they do lane swaps that are not to be seen anywhere else. Duo bot doing jungles and top lane, or whatever.  Why do they do this exactly, and when should this be done?


Why was the Programmers site on Stack Exchange created?

Why was Stack Overflow forked into  ? I don't understand this. I think it is stupid ;-)


I tried this:  find . -type f -size 128 -exec mv {} new_dir/  \;   Which didn't work, and it didn't give me an error. Here is an example of what the file looks like, when using stat -x  $ stat -x ./testfile | grep Size    Size: 128          FileType: Regular File


No space left on device in spite partition is not 100%

I am trying to do the following on my Linux machine CentOS release 5.8    cd /var/APPstoreldap/Home  touch test  touch: cannot touch `test': No space left on device   so I verified the partition disk space capacity in order to understand if  /var/APPstoreldap/Home partition reached to 100%  But what I get is that partition is only 51%   df -h | grep APPstoreldap   /dev/mapper/vg07-var  5.0G  2.7G  2.0G  51% /var/APPstoreldap/Home   so please advice why I get    No space left on device   What could be the problem here?  .  other test:  df -i| grep APPstoreldap  /dev/mapper/vg07-var  655360  655360       0  100% /var/APPstoreldap/Home


Why do stochastic processes involve time?

We define random variables as functions on a sample space $X(ω), ω ∈ Ω$. Here I do not see time being involved.  A stochastic process is a family of random variables, but they also are functions of two variables $X(ω, t)$ where $ω ∈ Ω$ and $t$ denotes time.  When I see a plot of a random process, I notice that the family of random variables is used as X-axis (or is it just only one random variable in diferent $t$ times?). The Y-axis is the range of this variables assuming they all are $i.i.d.$  I struggle in having a moderately clear concept of what a stochastic process is!


Can there be a set of numbers, which have properties like those of quaternions, but of dimension 3?

We all know what the complex numbers are : basically $$R^2$$ with a specified product formula, which is $$(a,b).(c,d)=(ac-bd,ad+bc).$$Hamilton defined the quaternions, which are a wonderful set of numbers, defined to be four-dimensional numbers, which too have a nice formula for products. One can prove the four square theorem using the Hurwitz integers and these numbers have a whole lot of marvellous properties. Can we define three dimensional numbers, who too have nice multiplication and interesting properties?  Also, when I think about algebraic number theory, I imagine rings and fields that are subsets of the complex numbers, whereas here we see how the quaternions have applications in number theory, and they are an extension of the complex numbers. What can we do when we don't restrict ourselves strictly to the complex numbers?  Note: one of the reasons the quaternions are a bit uncomfortable is that they don't commute with each other. However, we still have nice factorization properties when examining the Hurwitz integers. How do they arise? Can we define them as something like the ring of integers of a field?  EDIT:here are some links that give related information:  and .


Can you build a Windows To Go device with Windows 8 Pro OEM?

Microsoft introduced a feature called "" with Windows 8 Enterprise allowing to install Windows on a USB mass storage device similar to Linux Live distributions. The documentation supplied by Microsoft indicates that a  and that  to create the USB image.  On the web and , users report that something equivalent can be achieved without an Enterprise volume license.  However this assumes that the user has install media or an iso-File, containing a file called install.wim. Preinstall OEM versions do not ship with media and neither the Windows partition nor the created recovery medium comes with a file install.wim.  How can you achieve "Windows To Go" with OEM versions?


My bagel recipe calls for 1 tbsp of barley malt syrup. I have diastatic malt powder. How much powder would equal the tbsp of syrup?

My bagel recipe calls for 1 tbsp barley malt syrup. I have diastatic malt powder. How much powder would equal the tbsp of syrup?


I use PCTEX 5.1. When I print from a DVI window my embedded graphics line plots are too thin and almost fade out. When I export the document to a PDF and print it the graphics line weights are much better; however, the PDF driver actually makes every second page, text and graphics, is a little lighter. The dvi driver doesn't do that. So first, can I get the dvi driver to increase the graphics line weights, and second is there a patch for the PCTEX PDF driver problem.


Universal numbering for figures and lstlistings

I use ShareLaTeX for my thesis and I am facing a problem. I have used the following code to change figures' name to "Εικόνα" and lstlistings' name to "Εικόνα" too.   \renewcommand{\lstlistingname}{Εικόνα} \addto\captionsgreek{\renewcommand{\figurename}{Εικόνα}}   Now, the problem is that there may be a figure with name "Εικόνα 5.1" and also a listing with name "Εικόνα 5.1" because LateX uses different numbering for figures and lstlistings.  Is there a way to use a universal numbering for figures ang lstlistings?


Correct Site for a historical fiction question?

What is correct Stack Exchange site for a question about historical fiction?  Here is the context:  Many years ago I read a rather interesting book that tracked the life of two physical objects (a whip and a crown perhaps) over several centuries. The book was given to me as a child by my father, who read it as a child. Napoleon's invasion of Russia plays a role in the book with two characters surviving a winter using the remains of a horse for shelter. I am now trying to find the name of the book and if it is still in print.


XeLaTeX font rendering tend to be slightly bolder compared to PDFlatex

I noticed that there is a subtle difference of font rendering result between pdflatex and xelatex. xelatex tend to be slightly bolder compared to pdflatex. Even the file thumbnails in file manager look different (btw. I'm using Lubuntu linux).    I've tried using default font (Computer Modern) and Charter (\renewcommand*\rmdefault{bch}), they still look different.  % Computer Modern % Compiled using both PDFlatex and XeLaTeX % XeLaTeX result is slightly bolder  \documentclass[12pt]{article} \usepackage[a5paper, margin=20mm]{geometry} \usepackage{kantlipsum} \begin{document} \kant \end{document}   Computer Modern (PDFlatex):      Computer Modern (XeLaTeX):      Here's Charter...  % Charter font % Compiled using both PDFlatex and XeLaTeX % XeLaTeX result is slightly bolder  \documentclass[12pt]{article} \usepackage[a5paper, margin=20mm]{geometry} \usepackage{kantlipsum} \renewcommand*\rmdefault{bch} \begin{document} \kant \end{document}   Charter (PDFlatex):      Charter (XeLaTeX):      Do you have the same experience? Do you think it's normal? How to fix it? Thank you.  PS: screenshots are taken from Texmaker's PDF preview (75% magnification).  PS 2: I'm using Lubuntu linux, Texmaker, and default pdf viewer (Evince 3.10.3). I cannot compare using another OS.  UPDATE:  I tried another viewer, qpdfview (still under Lubuntu linux). The issue still persists. When viewed on an android tablet (using Acrobat and Google PDF viewer), they're just fine. There is no difference. So.. it is a viewer issue (as @Robert's commented below).  Here're screenshots of qpdfview...


How to get single character from user without /n or printing in console

I'm trying to make a game in python at my school, but we do not have pygame installed on the network this year.  I have an idea, but I need some code to run right when a key is pressed, and I don't want the keys I type to show on the screen, I wan't my own text to show. Is there a way to do this? I've been looking around, but I haven't found much that doesn't use PyGame or TKinter  Thanks! :)  Note: This is an extra curricular project, so I probably won't be able to get help from a programming teacher.


Is there any data explorer query that allows to find the users who bookmarked a specific question? EDIT: I tried searching for a direct hit on  but didn't find any post having a descriptive title for this functionality. As linked in the comments, two versions of the query can be found here , and here . Additional information on SEDE is available in the linked duplicate targets.