IID in real life /Machine Learning - When is data truly IID?

In a course I am studying at Berkeley, some student said about a particular Dataset "Data is not iid" and the lecturer agreed with him.    So once and for all, I want to understand, for real data, how often is it really iid and how can I decide myself?  For example, let's say that I take 20 million images from Facebook "randomly" (let's say that each image has some unique integer associated with it, and I pick a random integer every time).  Is this iid? What if I take a particular user's images, and then his friends's images etc in a BFS kind of way? Is this iid now?  While I understand the math definition I don't have the underlying distribution so it's very unclear to me. My gut feeling is that a real life dataset is almost never truly iid by the way.


I'm making a calculator in python 3 and I'm wondering if there is an option that can tell if the input the user gave is not a float. For example if the user wrote a word instead of a float the code will recognize it and print out something like: if num1 != float:     print("You Need To Enter A Number")


Question is to solve for Galois Group of $x^4-2x^2-2$ over $\mathbb{Q}$.  I know the roots of this polynomial are $\sqrt{1+\sqrt{3}},-\sqrt{1+\sqrt{3}},\sqrt{1-\sqrt{3}},-\sqrt{1-\sqrt{3}}$.  But, $\sqrt{2}i=\sqrt{1+\sqrt{3}}.\sqrt{1-\sqrt{3}}$. So, I concluded that splitting field would be $\mathbb{Q}(\sqrt{1+\sqrt{3}},\sqrt{2}i)$ (for some reason i am not very sure about, i have not written splitting field to be $\mathbb{Q}(\sqrt{1-\sqrt{3}},\sqrt{2}i)$).  So, i have splitting field as $\mathbb{Q}(\sqrt{1+\sqrt{3}},\sqrt{2}i)$.   What i do usually after i know that extension is of the form $F(a,b)$ with $F(a)\cap F(b)=F$, I calculate Galois group of $F(a,b)/F(b)$ and Galois group of $F(a,b)/F(a)$ and write their product as in $G=Gal(F(a,b)/F)$  I do the same here for $Gal(\mathbb{Q}(\sqrt{1+\sqrt{3}},\sqrt{2}i)/\mathbb{Q}(\sqrt{1+\sqrt{3}}))$, this is of order 2, sending $\sqrt{2}i\rightarrow -\sqrt{2}i$ (fixing $\sqrt{1+\sqrt{3}}$) So, I have $Gal(\sqrt{1+\sqrt{3}},\sqrt{2}i)/\mathbb{Q}(\sqrt{1+\sqrt{3}}))\cong \mathbb{Z}_2$.  The problem is with $Gal(\mathbb{Q}(\sqrt{1+\sqrt{3}},\sqrt{2}i)/\mathbb{Q}(\sqrt{2}i))$, I Have to prove that Galois group of $x^4-2x^2-2$ is dihedral group of order 8.I already have an element of order 2, I have to get an element of order 4 from $Gal(\mathbb{Q}(\sqrt{1+\sqrt{3}},\sqrt{2}i)/\mathbb{Q}(\sqrt{2}i))$ which is becoming more cumbersome.  Any help would be appreciated. Thank You.


Is the double dash still the posix standard for long switches?

I've read several question about double dash:      However I remember about a teacher 4 years ago telling me that -- was the posix way of dealing with long switches like --help or --color=. Today, I'm using a lot of command where this rule is not respected at all and the best example I can came up with is find where no long switches takes a double-dash even with the very annoying AIX find.    Was my teacher wrong? or does the rule changes since (which seems unlikely)? And finally, is there any posix rules about the length of option and - or -- ?


German Work Visa Expiring soon .. Can I still travel Europe as a tourist?

My freelance Work Visa expires in 10 days in Germany. It was a 12 month Visa.  I plan on heading to Spain and Denmark before flying back to Australia. Is this permitted?  Or ... will my 90 days be included in the 12 month Visa that is about to expire?  I'm hoping it isn't.


How to print a unicode string in python in Windows console

I'm working on a python application that can print text in multiple languages to the console in multiple platforms. The program works well on all UNIX platforms, but in windows there are errors printing unicode strings in command-line.  There's already a relevant thread regarding this: (  ) but I couldn't find my specific answer there.  For example, for the following Asian text, in Linux, I can run:  >>> print u"\u5f15\u8d77\u7684\u6216".encode("utf-8") 引起的或   But in windows I get:  >>> print u"\u5f15\u8d77\u7684\u6216".encode("utf-8") σ╝ץΦ╡╖τתהµטצ   I succeeded displaying the correct text with a message box when doing something like that:  >>> file("bla.vbs", "w").write(u'MsgBox "\u5f15\u8d77\u7684\u6216", 4, "MyTitle"'.encode("utf-16")) >>> os.system("cscript //U //NoLogo bla.vbs")   But, I want to be able to do it in windows console, and preferably - without requiring too much configuration outside my python code (because my application will be distributed to many hosts).  Is this possible?  Edit: If it's not possible - I would be happy to accept some other suggestions of writing a console application in windows that displays unicode, e.g. a python implementation of an alternative windows console


CPU clock speed versus CPU core count - higher GHz, or more cores for SQL Server?

We are beginning to provision a set of physical servers for a virtual cluster of SQL Server 2016 nodes within VMware. We will be utilizing Enterprise Edition licenses.  We plan on setting up 6 nodes, but there is a bit of a debate on what the ideal way to provision the physical servers with regards to CPU clock speed versus CPU core count.  I know this is largely dependent on transaction volume and number of databases stored among other software-specific factors, but is there a general rule of thumb that is advised?  For instance, is a dual 8-core, 3.2 GHz physical server (16 cores) more preferential to a dual 16-core, 2.6 GHz server (32 cores)?  Has anyone come across a white paper that further delves into this type of topic?


How do I find the first case of a word being present in a string using and change it LINQ?

Let's imagine we have this string: string Transport = "car motorcycle motorcycle plane train";  How can I find the first occurence of the word "motorcycle" in this string and change it in the original string to something else instead of having to create a separate string using LINQ?


How to move app data to external SD card without root

I have a Karbonn A15 with Android ICS (4.0.4), it's not rooted. I want to move the app data to my external sd card. I tried to move the /mnt/sdcard/data folder, just to check whether it releases any memory in the storage section in phone settings. But the internal storage was same, there was no change. Can anyone tell me where the app data resides in the internal memory? It's fine if I can move app data manually to the external SD card.


So I am trying to encode database selection, wich is done in php, in utf-8 but then it doesn't show C with colun. Like here:     Then I tried windows-1250 wich shows the coluns but it breaks nicknames of players.  Like here:   But I have red that UTF-8 should support czech letters, so what is going on?
      <?php header("Content-Type: text/html; charset=UTF-8");  // Doplňovačky $server = "xxxx"; $jmeno = "xxxx"; $heslo = "xxxx"; $dbnazev = "xxxx"; $pripoj = new mysqli($server, $jmeno, $heslo, $dbnazev);  // Kontrola připojení if ($pripoj->connect_error) {     die("Chyba pripojeni: " . $pripoj->connect_error); }  // Výtažek z databáze $sql = "SELECT name, time, server FROM redirect_follow"; $vysledek = $pripoj->query($sql);  // Podmínka zjišťující zda-li se v databázi nacházejí data if ($vysledek->num_rows > 0) {     echo "

Nick	čas	Server
";      // Jednotlivé řádky s daty     while($radek = $vysledek->fetch_assoc()) {         echo "
".              $radek["name"]. "	".              $radek["time"]. "	" .              $radek["server"] . "
";     }  // Pokud v databázi nejsou data, vyhlásí chybu     echo "
"; } else {     echo "Zadny vysledek"; }  $pripoj->close(); ?>


The exercise asked to proof this identity: $$\sum_{n=0}^Ncos(nx) = \frac{1}{2} + \frac{1}{2}\frac{sin((N+\frac{1}{2})x)}{sin(\frac{x}{2})}$$  $$ $$ The solution is using Euler's identity and goes as follows:  $$\sum_{n=0}^Ne^{inx} = \frac{1-e^{i(N+1)x}}{1-e^{ix}}$$ now, taking only the real part:  $$\sum_{n=0}^Ncos(nx) = Re\frac{(1-e^{i(N+1)x})(1-e^{-ix})}{|1-e^{ix}|^2} = Re\frac{1-e^{-x}-e^{i(N+1)x}+e^{iNx}}{(1-cosx)^2+sin^2x} = Re\frac{1-cosx-cos((N+1)x)+cos(Nx)}{2-2cosx} =$$ $$ =^\star \frac{1}{2}+\frac{sin(\frac{2N+1}{2}x)sin\frac{x}{2}}{2-2cosx} =^\star \frac{1}{2}+\frac{1}{2}\frac{sin((N+\frac{1}{2})x)}{sin\frac{x}{2}}$$   Now, I understand everything except the last two equalities (I marked them with $\star$ so it will be clearer). What were the trigonometric identities used in them? I was thinking double angle but I couldn't figure it out exactly. (The $\frac{1}{2}+$ part is understood obviously, since it's just splitting the nominator).  Thanks!


Kindly guide me through to configure environments.yaml file for hpcloud so that juju shall access HPCloud for deploying instances.  thanks,  Guru


Prove $d$ and $d'=\frac{d}{1+d}$ are equivalent metrics

Suppose $d'(x,y)= \frac{d(x,y)}{1+d(x,y)}$ for $x,y \in X$ and I want to prove $d$ and $d'$ are equivalent metrics on $X$.  I would show $$\lim_{n\rightarrow\infty}d(x_n,x)=0 \quad\Longleftrightarrow\quad \lim_{n\rightarrow\infty}d'(x_n,x)=0.$$  To prove $\lim_{n\rightarrow\infty}d'(x_n,x)=0 \Rightarrow \lim_{n\rightarrow\infty}d(x_n,x)=0$, is it valid to say:     if $0=\lim_{n\rightarrow\infty}d'(x_n,x)=\frac{\lim_{n \rightarrow > \infty}d(x_n,x)}{1+\lim_{n \rightarrow \infty}d(x_n,x)}$,      then $\lim_{n \rightarrow \infty}d(x_n,x)=0$.   If it's invalid, what am I doing wrong?  Thanks!


Runtime error when launching the app to the physical device using Android Studio and React Native

Does anyone know how to resolve this? I'm trying to run the app in debug mode using Android Studio but the app keeps crashing. I'm using react native.     E/AndroidRuntime: FATAL EXCEPTION: main       Process: com.catholicconnect, PID: 25838       java.lang.NullPointerException: Attempt to invoke virtual method 'boolean org.json.JSONObject.getBoolean(java.lang.String)' on a null object reference           at io.branch.rnbranch.RNBranchModule$1.onInitFinished(RNBranchModule.java:111)           at io.branch.referral.Branch.initializeSession(Branch.java:2604)           at io.branch.referral.Branch.initUserSessionInternal(Branch.java:1426)           at io.branch.referral.Branch.initSession(Branch.java:1099)           at io.branch.rnbranch.RNBranchModule.initSession(RNBranchModule.java:97)           at com.catholicconnect.MainActivity.onStart(MainActivity.java:67)           at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1392)           at android.app.Activity.performStart(Activity.java:7252)           at android.app.ActivityThread.handleStartActivity(ActivityThread.java:2970)           at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:180)           at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:165)           at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:142)           at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)           at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1831)           at android.os.Handler.dispatchMessage(Handler.java:106)           at android.os.Looper.loop(Looper.java:201)           at android.app.ActivityThread.main(ActivityThread.java:6806)           at java.lang.reflect.Method.invoke(Native Method)           at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)           at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)


How can I show that the equation  $$e^x-\ln(x)-2^{2014}=0$$ has exactly two positive roots?


I want to format the default inputField value on a Visualforce page.  I am pre-filling the number field with 1 but it is displaying as 1.00.  The underlying standard field has a data type of number(10,2).  How can I display the prefilled value as 1 with no decimals?  I consider this not to be a duplicate question because there is not a single right answer and helpful information has been provided here which is different to that provided in similar questions and will be useful to others.


Does AdSense penalise sites who say “please disable ad-block”?

Does Google AdSense penalise websites that say "please disable ad blocking software… it helps pay our bills… blah blah…"?  Example of "please disable adblock":    It’s kind of asking to see (or click) my ads which is against Google AdSense policies.


I have a 4th gen ipod. When I try to use a custom skin in Minecraft PE, it tells me, "that's not a Minecraft skin, silly".   It's frustrating because they are real skins. When my younger sister uses her fifth gen ipod to wear the same skins, it accepts them. Can I fix this?


I'm looking to learn to code in C and would like your opinion on what would be the best operating system for a laptop.   I have an older 'Dell' laptop, which is very slow, but I've seen reviews that say Ubuntu gave their old Windows PC's a new lease of life.   I'm considering bringing this old one back to life as a dedicated Ubuntu terminal.


Within Firefox (17.0), if I use CTRL+F to search for the word "time",  I only want the search to find "time", not other words that contain "time".  For example "datetime".  If I add a single or double quote to the word, it won't provide any results.  Is there a way to get around this, i.e., to search only for the exact text in the Find field?


Helping/explanatory notes for Landau&Lifschitz Physics Course

I've recently restored my interest on theoretical physics (I have a master degree in Electrical Engineering) and began my study with first volume of the Physics Course by Landau and Lifshitz. This is a very good and interesting book, and it just blows my mind (both in a positive and negative ways) - you spend really a lot of time trying to understand everything out of this textbook. Maybe someone can suggest somewhat sort of helping sidenotes for this book?


Compute: $\arctan{\frac{1}{7}}+\arctan{\frac{3}{4}}.$   I want to compute this sum by computing one term at a time. It's clear that  $$\arctan{\frac{1}{7}}=A \Longleftrightarrow\tan{A}=\frac{1}{7}\Longrightarrow A\in\left(0,\frac{\pi}{2}\right).$$  Drawing a right triangle with sides $1$, $7$ and $5\sqrt{2},$ I get that $$\begin{array}{lcl} \sin{A} & = & \frac{1}{5\sqrt{2}}\Longleftrightarrow A= \arcsin{\frac{1}{5\sqrt{2}}} \\ \cos{A} & = & \frac{7}{5\sqrt{2}}\Longleftrightarrow A= \arccos{\frac{7}{5\sqrt{2}}} \\ \end{array}$$  But this will not get me standard angles for $A.$


I would like to have an item (lets use a stick for example) to actiavte this command   /effect (player name) 24 1000000 255 true   upon right clicking. If anybody knows how to do that I'd be very thankful as I can't find the answer anywhere.


I've stumbled across a user whose  mentions they've got two 'Famous Question' gold badges:    Upon clicking the 'Famous Question' link, we see this:    Even more curious, they appear to have bronze badges from before the site was .  As I was writing up this post, the badge counts appear to have been corrected.   Is this a case of an account merge gone wrong?


I have a file that includes Camera Animation.  It renders the animation fine or a single frame after selection.  What I want to do though is manipulate my viewport view and render that as a single image.  What happens is I get the animated camera view at whatever frame it is on and not the viewport view.  I tried using the view-viewport render image option but that does not do a full render.  I also tried adding another camera but still it takes the animated one...  Please advise what I am doing wrong, and YES I am relatively new to this.


I have a problem with compiling and linking the main.cxx and Vec.cxx files, which are shown below.  To compile, I am using g++ with the following command:g++ -std=c++11 -c main.cxx Vec.cxx. To link, simply g++ main.o Vec.o. But doing this I get undefined reference errors to the create and uncreate functions, which are used by the constructors and the destructor.  Vec.cxx:  // Vec.cxx // Source file for Vec template class header.  #include "Vec.h"  #include <memory>  template <class T> Vec<T>& Vec<T>::operator=(const Vec& rhs){    if(&rhs != this){      // free array in the left hand side     uncreate();      create(rhs.begin(),rhs.end());    }    return *this; }  template <class T> void Vec<T>::create(){   data = avail = limit = 0;    return; }   template <class T> void Vec<T>::create(size_type n, const T& val){   data = alloc.allocate(n);   limit = avail = data + n;   std::uninitialized_fill(data,limit,val);    return; }   template <class T> void Vec<T>::create(const_iterator b,const_iterator e){   data = alloc.allocate(e-b);   limit = avail = std::uninitialized_copy(b,e,data);    return; }   template <class T> void Vec<T>::uncreate(){   if (data) {     // Destroy (in reverse order) the constructed elements;     iterator it = avail;     while(it != data){       alloc.destroy(--it);     }      // Return all the space that was allocated     alloc.deallocate(data, limit-data);   }    data = limit = avail = 0;    return; }   template <class T> void Vec<T>::grow(){   size_type new_size = std::max(2* (limit-data), std::ptrdiff_t(1));    iterator new_data = alloc.allocate(new_size);   iterator new_avail = uninitialized_copy(data,avail,new_data);    uncreate();    data = new_data;   avail = new_avail;   limit = data + new_size;    return; }   template <class T> void Vec<T>::unchecked_append(const T& val){   alloc.construct(avail++,val);    return; }   Vec.h:  #ifndef VEC_H #define VEC_H  #include <memory>  template<class T> class Vec{   public:   // define names    using iterator = T*;   using const_iterator = const T*;   using size_type = size_t;   using value_type = T;    // Size and index operators   size_type size() const { return avail - data; }   T& operator[] (size_type i) { return data[i]; }   const T& operator[] (size_type i) const { return data[i]; }     // Constructors   Vec() { create(); }   explicit Vec(size_type n, const T& val = T()) { create(n, val); }   Vec(const Vec& v) { create(v.begin(),v.end()); }    // Destructor   ~Vec() { uncreate(); }    // Assignment operator   Vec& operator=(const Vec&);    // push_back function   void push_back(const T& val){     if(avail == limit){       grow();     }      unchecked_append(val);     return;   }    // Iterators   iterator begin() { return data; }   const_iterator cbegin() const { return data; }   const_iterator begin() const { return data; }    iterator end() { return limit; }   const_iterator end() const { return limit; }   const_iterator cend() const { return limit; }   private:   iterator data;    // First element in Vec   iterator avail;   // One past the last allocated memory element   iterator limit;   // One past the last element in Vec    std::allocator<T> alloc;    void create();   void create(size_type, const T&);   void create(const_iterator,const_iterator);    void uncreate();    void grow();   void unchecked_append(const T&); };   #endif   main.cxx:  #include "Vec.h"  int main(int argc, char **argv){    Vec<int> v(10,2);     return 0; }   Edit: Thankyou for marking as duplicate, the link resolved my question. I moved the functions into the header file and everything works now.


Lebesgue integral $\int_{(0, \infty)} \frac{\sin x}{x} dm$ doesn't exist but improper Riemann integral exists

Show that the Lebesgue integral $\int_{(0, \infty)} \frac{\sin x}{x} dm$ doesn't exist but the improper Riemann integral $\int_{0}^\infty \frac{\sin x}{x} dx = \lim_{t\to\infty} \int_{0}^t \frac{\sin x}{x} dx$ does exist and is finite.


I am not native English speaker. May I ask you a question. I want to make an appointment with my friend at one particular end of a street. In my language we use two words to differentiate the two ends of a street, translated into English as "the head of the street" and the "tail of the street". What words do you use? Thank you.


How to use pygmentize automatically with less

I found pygmentize thanks to , but it would be great if it could be used to highlight text with less or maybe replace the command. Is there a way to do that? Thanks in advance.


Finding the last character of a file and adding a string after that?

Appending an extra line is simple as I can use echo "line" >> file but what if I want to add a string right after the last char in the file without starting a new line? What are some good ways to do this?


spacing between chapters in list of tables

tocloft seems to automatically add extra space between table entries from different chapters. I want a single space between all the entries in the list of tables. Right now I have one space between entries from the same chapter and two spaces between those from different chapters. Here's a MWE of what I have.   \documentclass[11pt, letterpaper]{thesis}  \usepackage[lmargin=1.5in, rmargin=1.0in, tmargin=2.0in, bmargin=1.0in]{geometry}   \renewcommand{\thechapter}{\Roman{chapter}} \renewcommand{\thesection}{\arabic{section}} \renewcommand{\thetable}{\arabic{chapter}.\arabic{table}}   \usepackage{tocloft} \addtocontents{lot}{Table \hfill\ {Page} \par}  \usepackage{titlesec} \usepackage{caption} \usepackage{ctable} \usepackage{tabularx}   \begin{document}   % List of Tables  \renewcommand{\cftlottitlefont}{\normalfont} \renewcommand\listtablename{\centerline{TABLES}} \renewcommand{\cfttabaftersnum}{.} \setlength{\cfttabindent}{0pt} \setlength\cftbeforechapskip{0pt} \setlength\cftbeforetabskip{11pt}  \listoftables  % End List of Tables   \chapter{Chapter One}  \begin{table}[htbp]    \centering     \begin{tabular}{lll}     \toprule     & Col 1 & Col 2 \\     \midrule     Row 1 & 11 & 12 \\     Row 2 & 21 & 22 \\     \bottomrule     \end{tabular}   \caption{This is table 1.1.} \end{table}  \begin{table}[htbp]    \centering     \begin{tabular}{lll}     \toprule     & Col 1 & Col 2 \\     \midrule     Row 1 & 11 & 12 \\     Row 2 & 21 & 22 \\     \bottomrule     \end{tabular}   \caption{This is table 1.2.} \end{table}   \chapter{Chapter Two}  \begin{table}[htbp]    \centering     \begin{tabular}{lll}     \toprule     & Col 1 & Col 2 \\     \midrule     Row 1 & 11 & 12 \\     Row 2 & 21 & 22 \\     \bottomrule     \end{tabular}   \caption{This is table 2.1.} \end{table}  \begin{table}[htbp]    \centering     \begin{tabular}{lll}     \toprule     & Col 1 & Col 2 \\     \midrule     Row 1 & 11 & 12 \\     Row 2 & 21 & 22 \\     \bottomrule     \end{tabular}   \caption{This is table 2.2.} \end{table}  \end{document}   I use \setlength\cftbeforechapskip{0pt}, but this seems to have no effect. I did find this:  and tried some of the suggestions but none seemed to work for me. Any ideas?


Two Docks are shown when Super key is pressed

My system shows two docks when I press the Super key.    I am using Dash to Dock extension.  The problem is resolved and works fine for couple of hours when I change the dock settings to bottom and then revert back to left (side). See the screenshot for resolved issue.  I am looking for permanent solution, kindly let me know if available.  Thank you.


In fact, I don't know how to write this expression on LaTeX:     And thanks in advance.


How do I delete friends from my Facebook account?

I have friends that are no longer active on my Facebook account.  How do I delete them and get them off my friends list?


Ubuntu 18.04 login loop after installation

After installing Ubuntu 18.04 LTS the OS does not work as it should. I have a login loop issue and the whole operating system does not work right.  My hardware:   MSI Z370 PRO NVIDIA RTX 2070


I'm using the wallpaper package to insert a jpg image in the background of a page. Specifically, I'm doing something like this:  \usepackage{wallpaper} \begin{document} \ThisULCornerWallPaper{1}{summary-analysis-bg.jpg} \end{document}   The image is in the same folder as the .tex file.  What if I wanted to compile the pdf but, instead of using an image from the same folder, use an image from a web address? The naive approach (replacing the file name/location with some image's web address) doesn't work.  Is there some approach that works?


This is an exercise from Ian Stewart's Galois Theory, $3^{rd}$ edition:     If $z_1,z_2,\ldots,z_n$ are distinct complex numbers, show that the determinant $$D=\left|\begin{array}[cccc]  11&1&\cdots&1\\ z_1&z_2&\cdots&z_n\\ z_1^2&z_2^2&\cdots&z_n^2\\ \vdots&\vdots&\ddots&\vdots\\ z_1^{n-1}&z_2^{n-1}&\cdots&z_n^{n-1} \end{array}\right|$$   is nonzero.       Hint: Consider the $z_j$ as independent indeterminates over $\Bbb C$. Then $D$ is a polynomial in the $z_j$, of total degree $0+1+\cdots+(n-1)=\frac{1}{2}n(n-1)$. Moreover, $D$ vanishes whenever $z_j=z_k$ for $k\neq j$, as it then has two identical rows. Therefore $D$ is divisible by $z_j-z_k$ for all $j\neq k$, hence it is divisible by $\prod_{j<k}(z_j-z_k)$. Now compare degrees.   My question is how to do this. I follow the hint and I'm thinking of $D$ as a cofactor expansion; is that the idea? Also, the fact that $D$ vanishes whenever $z_j=z_k$ for $k\neq j$ follows since it would have two identical columns, right? I don't see why $z_j=z_k$ would imply it has two identical rows, as the hint suggests. The fact that it is divisible by $(z_j-z_k)$ is easy since that would make $z_k$ a root for $k=j$, but I'm not quite sure I follow why the degrees would be different. I think the degree of the product would be $1+2+\cdots+(k-1)$, but then add these up for all $k<n$?   I appreciate any clarification that you can provide!


In Java, is there difference to initializate and use an object as Base b = new Derived() and Derived e = new Derived()?

If I have       public class Base{           public void method(){             System.out.println("I am base");         }      }      public class Derived extends Base{           public void method(){             System.out.println("I am derived");         }       }    is there a difference between  Base b = new Derived();   and   Derived d = new Derived();   ? And, would  b.method(); d.method();   print the same?


Distance between two independent normal random variable

What is the PDF of $Z=\sqrt{(X-x_0)^2+(Y-y_0)^2}$ when $X$ and $Y$ are i.i.d. normal random variables with zero mean, i.e., $X \sim N(0,\sigma^2)$ and $Y\sim N(0,\sigma^2)$?


How can I check if a value exists inside an array of objects in javaSript?

For eg.  [     {       x:1,       y:2      },      {        x:10,        y:20      }, ]   How can I check if x exists in both of the objects inside the array?  DESIRED OUTPUT:   if x doesn't exist in even one object inside the array ---> false  else ---->true  I have tried using the  method but not able to find the right logic to get the desired output.


Electromagnetic waves highest frequency and beyond?

If an electromagnetic waves frequency is generated by the change of voltage / current in a wire  or a atom decaying to get gamma waves.    What is the highest frequency possible give the faster the change in voltage/currect the higher frequencies generate?  So as the frequency goes up and as the change in voltage/current becomes instant, (if possibe) what is the state on the wave between the upper and lower limits of the wave? Is this a state possible?


I have confused to uninstall python3 or fix my VPS Ubuntu  Im using Ubuntu 16.04.5 LTS (GNU/Linux 4.4.0-31-generic x86_64)  I tried to uninstall all python packages  sudo apt-get purge python3  And getting this error  dpkg: error processing package python3-pkg-resources (--remove):  subprocess installed pre-removal script returned error exit status 127                               Processing triggers for libc-bin (2.23-0ubuntu10) ... Errors were encountered while processing:  python3-lxml  python3-pip  python3-apt  python3-pyparsing  gir1.2-ibus-1.0:amd64  hplip-data  python3-blinker  python3-bs4  python3-cairo  python3-chardet  python3-dbus  python3-defer  python3-feedparser  python3-gi  python3-guacamole  python3-httplib2  python3-idna  python3-jwt  python3-louis  python3-markupsafe  python3-padme  python3-setuptools  python3-problem-report  python3-ptyprocess  python3-pyasn1  python3-pycurl  python3-six  python3-wheel  python3-xdg  python3-xkit  python3-xlsxwriter  dh-python  python3  python3-pkg-resources E: Sub-process /usr/bin/dpkg returned an error code (1)   I tried other way from other site,error still same And i tried to reinstall my ubuntu with command line  apt-get install --reinstall ubuntu-desktop  I dont know should i do to fix my ubuntu and reinstall my python.  Note: I tried to run python3 it not working with reasons python3 is not package and i run python3.7 it working fine,idk python3.7 thats reall python package i have or something else :/  Im so appreciate any help


Can “zealot” have a positive connotation?

A zealot is a person who is fanatical and uncompromising in pursuit of their religious, political, or other ideals.  I have never seen this word used with positive connotation, but could it (without causing raised eyebrows)? For example, “Gandhi was a zealot and should be admired by all who believe in non-violence.”  Also, do “zealous” and “zeal” carry the same connotation as “zealot”?


I'm a beginner in Linux. I've had my usb prepared with UNetBootin with Ubuntu 18.04 Live x64 LTS.  The problem is, my PC won't boot to usb drive. Even though I've change the boot sequence and try many option, UEFI, legacy, etc.  I've even tried different method of usb installers, Etcher, Rufus and they just stuck in blank screen after ubuntu logo displayed.   Please help this beginner so I can start experiencing this new world of open source.  My PC spec is ECS H61 mainboard. Intel core i5 Ddr3 4gb Seagate 500gb HDD.  Thanks in advance.


Installed Ubuntu in dual boot mode with two disks drive (SSD and HDD)

I started up installing Linux from USB, and try to install Ubuntu 18.04 LTS alongside Windows 10.  My laptop has 2 hard disks(128GB SSD Windows 10 pre-installed and 1TB HDD). First time when I wanted to install Ubuntu,I selected SSD(sda) for bootloader, installer says I can't use it.  When I select sdb(1TB HDD) for bootloader and root and /home(ext4)(and one time I added swap area partition), I put 250 MB for EFI. Ubuntu has been installed and when I restart it after installation, a black page showed to me and after 15 minutes, I restart again and after selecting Ubuntu from grub menu, OS doesn't startup and giving me this picture instead:      (disabled secureboot)


Centralizer of $\mathbb{C}[G]$ in $\mathbb{C}[H]$

I found this result, but can't understand how to prove.  Let $H$ be a subgroup of $G$. Then prove $Z(\mathbb{C}[G],\mathbb{C}[H])$ is commutative iff every irreducible $G$ module when restricted to $H$ splits into irreducible $H$ modules of multiplicity at most $1$. Where $Z(M,N)=\{m \mid mn=nm , \forall n\in N\}$


What does a "torus obtained by identifying each of the three pairs of opposite edges of a regular hexagon" look like? What is it called?

Wikipedia's  says:  The quotient of the complex plane C by the lattice containing all Eisenstein integers is a complex torus of real dimension 2. This is one of two tori with maximal symmetry among all such complex tori.[citation needed] This torus can be obtained by identifying each of the three pairs of opposite edges of a regular hexagon. (The other maximally symmetric torus is the quotient of the complex plane by the additive lattice of Gaussian integers, and can be obtained by identifying each of the two pairs of opposite sides of a square fundamental domain, such as [0,1] × [0,1].)  I understand how identifying each of the two pairs of opposite edges of a rectangle makes a "normal torus" or donut, but I can't visualize what this torus might look like. Does this torus have a name? Can it be illustrated?


Getting subbasin area of each specified river segment？

I have a DEM file of one district, and I have used those following tools in spatial analyst tools in ArcGIS 10.1 to get files related to the original DEM file：   Fill Flow direction Flow accumulation   Besides, I already have the point shapefile that these points are vertices in the river the one belongs to the same district as DEM file, so I use the point shapefile as the pour points in the river.   I use the watershed tool, setting my flow direction file and point shapefile as input files, try to get the subbasin area in this river.  I just got this：   But here's the schematic photo that I want：I want to get every subbasin area and calculate them, assigning them to the attribute of the designated segment   In what way should I use tools in ArcGIS to achieve my goal, thanks for giving me any suggestion!  Although I have a great answer to this question, I got another problem afterwards：


Synchronized in the method signature vs. synchronized block in part of the method

I'm aware that including the word synchronized to the getNext() method signature would make the method completely thread safe. But what if in the body of the method I surround only the portion where the actual incrementing is being done with a synchronized block? Will this still be a completely thread safe incrementer? What's the difference?  public class NextNumberGenerator {      private int number = 0;      public int getNext() {         synchronized (this) {             number = number + 1;         }          return number;     } }


How to show that for $a,b\in \mathbb{C}: |a-b|=|1-a\overline{b}|  \Leftrightarrow |a|=1 \, \lor \, |b|=1$   I defined $a:=x+iy$ and $b:=u+iv$ which resulted in quite an algebra mess. Is there a simpler method to solve such statements?


Independence of non-constant real variables

Show that if $\Omega$ has $n \in \Bbb N$ elements, then it exist at most $2^n$ independent non-constant real-valued random variables on $(\Omega,\mathcal F, P)$.  A real-valued random variable is called constant if $P(X=a)=1$ for some $a \in \Bbb R$.  The only idea that I have in mind for now is to somehow use variance since a random variable in not a constant one if its variance is not $0$. Also I suppose that the given sigma-algebra has exactly $2^n$ elements so it might be applied in the solution ?  I just really a starting point for this proof. Any hint will be highly appreciated.


Drupal permission resticted to own node in relation to another one

I have a pretty nasty problem with events and venues in Drupal. Let say that registered user can add a venue - there is no restrictions. Now I want to make users able to add an event but this one can be assosiated to users own venue not to others. How to limit this access?   I have both events and venues as nodes.   Any ideas?  Cheers Pawel


Is it possible inherit from Template class C++ specialized on himself

Let's say we have base class Table  template <typename T> class Table { public:   Table();   virtual ~Table() = default; private: // get all column names as list virtual std::list<std::string> getAllColumnsImpl(); };   and I want inherit TestTable class and override method getAllColumnsImpl from base class:  class TestTable : public Table<TestTable> { public:  TestTable();  virtual ~TestTable() = default;  std::string Description; int Count;   private: // get all column names as list std::list<std::string> getAllColumnsImpl() override; };   Is it possible in general ?  For example I have linker errors like:   error LNK2019: unresolved external symbol "public: __cdecl Table<class TestTable>::Table<class TestTable>(void)" (??0?$Table@VTestTable@@@@QEAA@XZ) referenced in function "public: __cdecl TestTable::TestTable(void)" (??0TestTable@@QEAA@XZ)


I have downloaded Ubuntu to a 8 GB flash drive and  I am not sure how to load it onto my PC (Acer Aspire z1800 running Windows 7)plus I don't want to lose Windows 7 and I would eventually like to have both on the hard drive but not until I have used Ubuntu for a while.   I'm close to 80 years old and I am not very PC literate. So please can you keep any answers very simple. A step by step instructions would be very nice.


iTunes charges when it's advertised as free

Why does it advertise free for 3D tour of ancient Jewish temple then when I try to install the app it asks for credit card details


Can a spell be prepared once and cast multiple times?

Our group had some confusion about preparing spells for a Wizard and Cleric. The rules say that you prepare a number of spells from your list and that you tick off spell slots when you cast a spell. In D&D 3.x, if you wanted to cast a spell multiple times you had to prepare it multiple times, but we couldn't figure out from the rules whether or not this was the case in D&D 5e.   So can a spell be prepared once and then cast multiple times?


Trying to create a "copy" of an object using a constructor in Java, but what happens to what I pass in?

Ok - the title doesn't make much sense. I apologize in advance - I'm relatively new to some Java concepts:   I have a class, which looks a little like this (simplified):   public class SomeContainer {     T someEntity;     Map<String, Map<String, List<SomeOtherClass>>>> someCrazyMapping; }   I have a variable of type SomeContainer, let's call it container1.  I want to make container2, which is essentially an exact copy of container1, but I'm going to make some modifications to container2's "crazy mapping".  What I tried doing is creating a "copy" of container1 as follows:  SomeContainer container2 = new SomeContainer(container1.getSomeEntity(),  container1.getSomeCrazyMapping())   The constructor is an @AllArgsConstructor - and just copies the values as this.someEntity = someEntity (etc.)  If I put entries into the "crazyMapping" in container2, does container1 get affected at all? I am running it to check how it behaves, but if someone could explain how this works, it would be greatly appreciated.


Positive integers $n$ so that $n^2$ divides $2^n+1$.

Find all positive integers $n$ for which $n^2$ divides $2^n+1$.


Where is the terminal or command line in ubuntu 14.04 LTS? I can't seem to find it. Can you please direct me to find it so I can type in the formula for caffeine so I can stop my screen from dimming? Please advise asap. Thank you, Dianne


The side of a square is increasing at a rate of 5cm/s. At what rate is the area changing when the side is 10 cm long? Question continued below..

.... At what rate is the perimeter changing when the side is 10cm long?  I am not very good at these related rate questions so if anyone could help me through it that would be great.   From what i know and if i am correct, this is what i have so far..  ds/dt = 5 A = s^2   Let A be area in cm, Let s be the length of the side, Let t be the time in seconds   So we are looking for dA/dt when s = 10? If i am correct?  If so then would this be the formula?  dA/dt = d/dt (s^2) = 2s(ds/dt)?    Now i am a little confused.


The only natural number $x$ for which $x+\sqrt{-2}$ is a cube in $\mathbb{Z}[\sqrt{-2}]$ is $x=5$

Let $A =  \mathbb{Z}[\sqrt{-2}]= \{a+b\sqrt{-2} \ : a, b \in \mathbb{Z}\}$. Show that the only natural number $x$ for which $x+\sqrt{-2}$ is a cube in $A$ is $x=5$.   So I have to show that there exists $c,d \in \mathbb{Z}$ such that $(x+\sqrt{-2})^3= c + d \sqrt{-2}$. From the last equation, I obtain $x(x^2-6) = c \in \mathbb{Z}$ and $3x^2-2= b \in \mathbb{Z}$, and here I blocked. Could I conclude from both equations? If not, is there exists another way to proceed (hint)?  Thanks!


Does opening and closign a wormhole to send a message within seconds across the galaxy violate causality?  Wouldn't different observers disagree about the order of events and what effected what? Is that observation just an illusion after all?  Update: Note that the Wormhole is stationary in both places and that both places can be considered to be in the same frame of reference. Also I am not sending matter, but information in form of light through the wormhole to simulate FTL-Communication.


Hi I have a quick question. I know this may be a common question. If N3L states that there's an equal and opposite force, why do things still move?  I have read up a lot and this is my understanding. If a finger exerts a force on a box, then box will move/accelerate. At the same time, box exerts an equal force on the finger. The motion of box(assuming no friction) is affected only by force from the finger. (I think the term is System = box). Thus, the reaction force from box only affects the motion of finger and has no relevance to the motion of the box.  However, I came to this question. If the reaction force from the box on the finger is equal to the force from the finger to the box, then there must be some other kind of force on the finger that is opposite to the reaction force and greater, since the finger is accelerating/moving. What is that force?


Integrating squared absolute value of a complex sequence

I was reading through my book in complex analysis and i encountered this problem. Given, $F=\sum_{n=0}^{\infty} a_nX^n$ is a convergent power series with radius of convergence R. We are asked to show that for every 0$\leq$r$<$R that $$ \int_0^{2\pi}\mid F(re^{it})\mid^2\mathrm{d}t={2\pi}\sum_{n=0}^{\infty}\mid a_n\mid^2r^{2n}$$ This is not my homework but after some effort I have no clue how to solve this one. The assignment was in the chapter about convergent power series and there is nothing about integrating, thus I assume it should be solvable by real analysis calculus. I would appreciate if someone would help me with this one. Regards, Raxel.


Can you walk me through how to download and install Windows?

For the last few months I've been running an HP Compaq 6000 Pro on Linux Ubuntu. I use a laptop that ran Windows 8.1 but I swapped ro this Ubuntu since that motherboard on the laptop fried. I tried it and while I can certainly see the freedom and liberty it offers, I can't fully appreciate it. I've just come to the terms that it isn't for me and I would like to switch to Windows.  So, since this community is pretty helpful and seems to specialize with anything related to Ubuntu, how do I do it without ruining the computer?  P.S: I read something about being able to download a "disc" something from the Windows website  but that it needs a CD or USB drive with at least 5 gigs of free space to be stored. It said something about getting 30 days free before needing a license key to progress but, as you now know, I'm terribly inexperienced at any of this.  Please... like I'm an idiot... (I got this computer from a relative and the extent of my knowledge on booting is literally pressing F1 in the boot up menu.)


Was there any Agents of SHIELD tie-in to Civil War?

When the last few MCU movies came out, there had been corresponding sequences and tie-ins with the ongoing Marvel's Agents of S.H.I.E.L.D. series.  Winter Soldier's introduction of Hydra-within-SHIELD fell right into lockstep with the series' traitor plotline.  Thor 2 lead into the series' team having to do cleanup in the UK.  Age of Ultron revealed that Coulson's super-secret plan was actually readying a SHIELD Helicarrier for Fury's use.  Now, I admit that I sped through the last six episodes of S.H.I.E.L.D. in preparation for watching Civil War this weekend, so maybe I missed something.  However, I didn't notice any particular lead up to anything revealed in the movie this time around.  Did I miss anything?  Yes, I caught the cute little reference of HIVE/Ward saying "Only billionaires can have super suits and only the government can make super soldiers, which will lead to a war of its own", but was that it?  Did anything else from the series have any impact or cause any revelations in the movie?  Regarding the question  that question is from 7 months ago and does not address the movie that came out this weekend.


Claim different routes with a single station in Ticket to Ride Europe

I know that a station can only be used to serve as a connection over another player's route between the station-city and another city.    But can a single station be used to claim different routes for different destination tickets or must the same (one) route be used for all of your destination tickets?    The rules are a bit unclear, but my understanding is that the same route must be used for all of your destination ticket.


I've heard that consuming sugars can induce many different health problems. I wouldn't really mind excluding them from my diet, but would it be safe? Or do we have a minimum sugar requirement?


Calling member template function within non-member template function

I've got this example which compiles under MSVC2015 but not Clang. I'm programming code that I want to run everywhere. I get an "error : expected expression" message. I've searched SO but I can't seem to find this exact same problem.  template<int T> class SomeClass { public:     template<int S>     int Foo()     {         return S;     } };  template<int X> void Fun() {     SomeClass<X> c;     c.Foo<0>(); }  int main() {     Fun<0>(); }


Could we feel a jetlag-equivalent effect when we travel a long distance in the North-South direction? We would be moving from summer to winter in one day. Doesn't this affect our biological clocks?


Why is the associative property valid for modular arithmetic?

The associative property is defined in the picture above. The screenshot is from Discrete Math and its Applications 8th edition, by Kenneth Rosen. Also, we have this definition for modular multiplication and addition.     Both of these images are on page 257 of the textbook.  My question is why is the associativity property valid? Every other property listed is very intuitive, but I don't know how I'd go about proving the associative property.


How can one show from General Relativity that gravity is attractive force, and under which conditions it becomes repulsive, also why positive energy vacuum drives repulsive gravity?


Popular symbols for disjointness relation of two sets?

Is there any standard or popular symbol to indicate that two set A and B are disjoint?  Of course, it can be described by:     But it is still way too long. Is there any popular symbol for the disjointness relation R such that we can write as below?


Half of my disk space is assigned to Ubuntu. How can I move some to Windows?

I don't need half my disk space on Ubuntu and I would love to move it back to Windows without having to uninstall and install Ubuntu all over again. I'd appreciate any help on this.


My game consists of a player that hopes between ropes. For now, I created the player and the rope classes.  Each one contains details about the object and its movement patterns. What is the next step in orfer to link between them?   Iwant the player to stick on a rope once they have the same x. Should i create an activitt Game that implements this attach method? Thank you.


Finding the integral of $\frac{x}{e^x + 1}$

I've having some difficulty with finding this integral:  $$ \int_0 ^{\infty} \frac{x}{e^x + 1}$$  Now usually I would use the monotone convergence theorem to write (using geometric series):  $$f_n (x) = \sum_0 ^n (-1)^k x e^{-(k+1)x},$$  but this isn't a sequence of positive terms, so how do we justify moving the integral inside?  Thanks.


I see this message across my screen from time to time stating (roughly): You have lost your service field upgrade.  I know that field upgrades are given to squads from their commander, but why did I lose it?  Did my commander demote our squad?  Or do I have to accept the field upgrade as Squad Leader?


How can I stop SQL Server Reporting Services 2008 going to sleep?

I have SSRS 2008 set-up on a server.  All works fine except that if left inactive for a length of time the next time a request is made to the server it takes a long time for it to service it.  I think this is to do with the worker process being shutdown after being idle for a certain length of time.  However, as SSRS 2008 isn't managed through IIS I can't find any settings that I can adjust to stop this from happening.  In IIS I'd go to the Performance tab of the Application Pool Properties and choose not to shutdown the worker process.  How can I do this for SSRS 2008?


How to protect your money from a hyperinflation?

Let’s say someone supposedly fears a hyperinflation and hence the devaluation of money (or historically speaking the implementation of a new currency, e.g. post-war Germany). This extreme inflation is caused by an over aggressive political guideline, too much debt/suspensions (in those current times), external factors (war) or anything alike - there are many reasons to why such things could happen! What’s the best way of protecting one’s liquid wealth (the currency someone has, not the net worth) - in different price categories? Someone with $300k+ lying around might invest in a house, an individual with “just” e.g. $10k might purchase Gold? Other currencies? Please share founded opinions in regards to historical events at best, i.e. “Gold is a solid option as seen in [...]; you barely face any conversion loss and it’s pretty stable!” Proof-testing those hypothesis in different scenarios would be top-notch, e.g. “in times of a war your ‘saved cash’ in real estate might get destroyed hence leave you without any substantial value -> Gold is better because [...]”


Why do many humans have bad eyesight, such as near-sightedness, which hampers performance in a wide variety of tasks? Shouldn't there be evolutionary pressure towards better eyesight?


Running Cron every 2 hours and 5 minutes

I need create a cron job running every 2 hours and 5 minutes, is this possible? This doesn't work since is running each 5 minutes :(  user@server$ crontab -l 0,5,10,15,20,25,30,35,40,45,50,55 0,2,4,6,8,10,12,14,16,18,20,22 * * *  date >> /tmp/cron-test01.out user@server$ cat /tmp/cron-test01.out Mon Sep 19 10:05:00 GMT 2016 Mon Sep 19 10:10:00 GMT 2016 Mon Sep 19 10:15:00 GMT 2016 Mon Sep 19 10:20:00 GMT 2016 Mon Sep 19 10:25:00 GMT 2016 Mon Sep 19 10:30:00 GMT 2016 user@server$


Database does not update automatically with MySQL and Python

I'm having some trouble updating a row in a MySQL database. Here is the code I'm trying to run:  import MySQLdb  conn=MySQLdb.connect(host="localhost", user="root", passwd="pass", db="dbname") cursor=conn.cursor()  cursor.execute("UPDATE compinfo SET Co_num=4 WHERE ID=100") cursor.execute("SELECT Co_num FROM compinfo WHERE ID=100") results = cursor.fetchall()  for row in results:     print row[0]  print "Number of rows updated: %d" % cursor.rowcount  cursor.close() conn.close()   The output I get when I run this program is:     4Number of rows updated: 1   It seems like it's working but if I query the database from the MySQL command line interface (CLI) I find that it was not updated at all. However, if from the CLI I enter UPDATE compinfo SET Co_num=4 WHERE ID=100; the database is updated as expected.  What is my problem? I'm running Python 2.5.2 with MySQL 5.1.30 on a Windows box.


I'm new to python, just have one question:  Python don't need to declare variable types. For example, when we use functions, we don't declare which type should be passed in. So sometimes, I can't figure out which type the passed in parameter actually is or do I pass in an invalid parameter.  For example, a parameter named: run_date, Its type can be string or datetime or date. I have to find it from the code...  Is there a way to solve this problem? I think I should do good naming. But howto?  I don't mean to check the type in the code. I just get confused with the function parameters when coding... I always forget which type the parameter is...


I'm currently working on a project where the user is required to register, and we are considering only providing social logins, and not providing a site only registration.  The reason behind this is that the data we will be storing for the user is trivial, and the only sensitive thing would be email and password. However if we use social logins this data is handled for us by the 3rd parties.  This means that we would not need to purchase a SSL Certificate for the website and save money on something that is a hobby/passion project.  We believe if we provide a decent spread of social logins that 99% of the audience will be covered anyway. We are also mindful not to overload the user with too many choices, so were thinking of providing: Facebook, Google+, Twitter, Microsoft  Would this cause a negative effect on sign up rate? Are these sites the optimum 4 to reduce overload, but cover the audience?


How to remove Apple's activation lock in iPad Air

I have an iPad Air which someone gave me, and he said that he's forgotten all his Apple ID details and stuff. So I tried my best to try to unlock it (already used the DNS bypass). What I'm trying to ask here is, is there a way to completely remove the activation lock? Maybe by jailbreaking it. My iOS is version 10.1.1


Just wondering, does compasses can stand on its own?  Or should it be accompanied by a pair of?


Highest compression for files(for web transfer)?

I have seen some highly compressed files around, such as 700MB of data compressed to around 30-50MB.  But how do you get such compressed files? I have tried using software like WinRAR and 7Zip but have never achieved such high compression.  What are the techniques/software that allow you to compress files so well?  (P.S. I'm using Windows XP)


A process called "System" on my windows10 laptop is using all the memory. I can't play any games because of this. Chrome too freezes. It's almost impossible to use any program.  I've 8GB Ram. The "system" process is using 70-80% of it.


If $f(z)$ is analytic on the unit disk and $\left| f \right| \leq \frac{1}{1- \left| z\right|}$ then bound the derivative

Let $f(z)$ is analytic on $D = \{ z \in \mathbb{C}: \left| z\right| < 1\}$ and $\left| f \right| \leq \frac{1}{1- \left| z\right|}$ then show that $\left| f '(z) \right| \leq \frac{4}{(1 - \left|z\right|)^2}$.  I don't know what to do here, we know that the function is bounded by the series $\sum_k \left|z\right|^k$ and that it looks like we are taking the derivative at both sides of the inequality (I know that this is not correct). I tried to use Cauchy's integral formula without success.


SKINNING - How to remove specific vertex relation to bone

I've create a model and a rig by myself to understand how it's working but i'm stuck with one thing : some vertex are related to a bone and I don't want it. Obviously to avoid that kind of result : (look at the pelvis which move withe the hand controller)    I tried to delete the relation but it's impossible to see the relation of a group of vertex, it's not listed anywhere because it's not an object but some vertex of this object.  Do you know how to solve that ?  Many thanks in advance, François


My ubuntu boot screen shows up in a strange low resolution, almost text mode, instead the usual and sleek white "ubuntu" over dark background. It's not a big issue because when GDM loads everything becomes ok, but If there's an easy way to fix it I would like to give it a try.


I've come across something which appears strange to me, but at the same time makes some sense for reasons I don't know.  I have this enum:  [Flags] public enum Flags { RemoveQuoteMarks = 1, t1 = 2, t2 = 4, t3 = 8, t4 = 16, t5 = 32, t6 = 64, t7 = 128 }   Before, I didn't manually set the enum values, they index from 0 and standardly increase by 1 right?  Well I noticed odd behavior when I tried to load this string:  string value = "t1, t3, t4, t7";   and parse it using:  Flags flags = (Flags)Enum.Parse(typeof(Flags), value);   and the result was just 't7', so I did some research, and noticed a lot of others used manual indexing where each enum value was doubled by its previous (e.g. 't3 = 8', 't4 = 16'), so I applied this rule to mine, and it worked, my parsed enum had now shown as:  t1, t3, t4, t7   as desired, why do I have to manually configure my enum values like that?


Creating and using a bootable USB for a new build

I'm brand new to building computers and just finished putting together a decent CAD machine.  Now I'm looking for an operating system, I have no previous system installed and was wondering how the process works for a fresh computer? I have access to a Mac laptop and plenty of empty USB sticks.


ASP.NET Website's BIN directory and references

Imagine the following solution:   Website ABC.com (not Web Application) BLL (business logic layer in a seperate assembly) DTO (dto objects in their own assembly) DAL (data access layer in it's own assembly as well).   The BLL has a reference to the DAL. The BLL has a reference to the DTO layer. The Website project references the BLL.    When one compiles the website project, the following DLLs will appear in the BIN directory: BLL.dll DTO.dll DAL.dll    When one goes to preview the site, an error occurs about not having the necessary assembly references... Now if one right clicks on the website project, Add Reference, and explicitly add the reference to the missing assemblies, it will work fine.  It seems to me like ASP.NET pulls the referenced assemblies of the referenced assembly being added/referenced in the website.    Why does one need to add explicit references to the references of the references... ? Sorry if I'm not wording this correctly or if it confusing.


Linear Algebra - Elementary Canonical Forms

Let $N$ be a $2\times2$ complex matrix such that $N^2=0$. Prove that either $N=0$ or $N$ is similar over $\mathbb{C}$ to  $$\begin{pmatrix}0&0\\1&0\end{pmatrix}$$


No network device after installing Ubuntu 16.04

Recently, I bought a Lenovo T470 with preinstalled Windows 10. I install Ubuntu 16.04 in parallel by USB boot. Wifi connections are not displayed as in many other posts.  My home directory is encrypted, in case it is relevant.  After checking, there no Wifi / network device available.  lspci -n -d 14e4   ( no response )  iwconfig enp0s31f6  no wireless extensions. lo         no wireless extensions.   Neither is any wireless driver displayed in settings.  I suspect that Ubuntu cannot recognize my wireless device. Is there any suggestion / more information needed to solve the problem?  Update 1 : After Pilot6's comment, I check again and there is still no response.   lspci -knn | grep Net -A2   Update 2 :  lspci 00:00.0 Host bridge: Intel Corporation Device 5904 (rev 02) 00:02.0 VGA compatible controller: Intel Corporation Device 5916 (rev 02) 00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21) 00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21) 00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI (rev 21) 00:1c.0 PCI bridge: Intel Corporation Device 9d10 (rev f1) 00:1c.6 PCI bridge: Intel Corporation Device 9d16 (rev f1) 00:1d.0 PCI bridge: Intel Corporation Device 9d18 (rev f1) 00:1d.2 PCI bridge: Intel Corporation Device 9d1a (rev f1) 00:1f.0 ISA bridge: Intel Corporation Device 9d58 (rev 21) 00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21) 00:1f.3 Audio device: Intel Corporation Device 9d71 (rev 21) 00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21) 00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (4) I219-V (rev 21) 04:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device b822 3e:00.0 Non-Volatile memory controller: Toshiba America Info Systems Device 0115 (rev 01)  lsusb Bus 002 Device 002: ID 0bda:0316 Realtek Semiconductor Corp.  Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 004: ID 04f2:b5ab Chicony Electronics Co., Ltd  Bus 001 Device 003: ID 0bda:b023 Realtek Semiconductor Corp.  Bus 001 Device 002: ID 058f:9540 Alcor Micro Corp. AU9540 Smartcard Reader Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   Update 3 : More information provided after asking on LaunchPad  sudo lshw -C network   *-network        description: Ethernet interface        product: Ethernet Connection (4) I219-V        vendor: Intel Corporation        physical id: 1f.6        bus info: pci@0000:00:1f.6        logical name: enp0s31f6        version: 21        serial: 54:e1:ad:1f:de:57        capacity: 1Gbit/s        width: 32 bits        clock: 33MHz        capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k firmware=0.1-4 latency=0 link=no multicast=yes port=twisted pair        resources: irq:122 memory:ec200000-ec21ffff  lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 16.04.2 LTS Release:        16.04 Codename:       xenial  uname -a Linux simon-ThinkPad-T470 4.8.0-36-generic #36~16.04.1-Ubuntu SMP Sun Feb 5 09:39:57 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux  rfkill list 0: hci0: Bluetooth         Soft blocked: no         Hard blocked: no 1: tpacpi_bluetooth_sw: Bluetooth         Soft blocked: no         Hard blocked: no


When did letter "R" lose its "rolling" pronunciation in English, and how?

In most Latin languages (Spanish, Portuguese, Russian...), "R" is pronounced in a "rolling" way. For example, "relájate" pronounces like "llle-la-ya-tee", "русский" pronounces like "lllus-kia". This pronunciation does not apply to English, and it's obvious that it hasn't applied to English since a long time ago. It looks like the non-rolling pronunciation in English is actually the minority. So why is this happening? And when did the change take place?


What is the point of buying new Jump Ships?

So the game starts you out with a basic Jump Ship to get around the system.  There's a vendor in the tower who sells other Jump Ships.    Do these other ships do anything special?  Or are they just hats? Expensive, cool looking, warp capable hats?


Lorentz invariance of the integration measure

This is regards to the lorentz invariance of a classical scalar field theory. We assume that the action which is $S= \int d^4 x \mathcal{L}$, is invariant under a Lorentz transformation. How do you prove that the integration measure $d^4 x$ is Lorentz invariant.


Force \displaystyle throughout document (including subscripts and fractions)

How do I force \displaystyle to all instances inside fractions, superscripts, and subscripts throughout the entire document (including intext)?  Basically I am looking for something that effects   \frac{1}{\displaystyle \Big[1-\frac{q^{\displaystyle{2}}}{0.71}\Big]^{\displaystyle{2}}}   but without having to insert \displaystyle all over the code.  Is it also possible to retain \textstyle \subscriptstyle functionality to force the smaller type on certain occasions?


Assuming $ab^2 = b^3a$ and $a^2=1$ prove that the order of $b$ is $5$.

Let $G$ be a group and $a,b \in G$ with $a \ne 1$ and $b \ne 1$. Assuming $ab^2 = b^3a$ and $a^2=1$ I need to prove that the order of $b$ is $5$.   I have proved by contradiction that it can't be 2 or 3 but I don't know how to prove that it must be 5 and it can't be 4.


I would like to know what is the difference between "How is your day thus far?" vs. How is your day so far? and if there is any significant difference between the two questions. I always assumed that they essential meant the same thing, but I am uncertain at this very point. Is there any one who would be willing to help me understand the differences between the two. Any help would be greatly appreciated.


Natural word ordering  I'm wondering if anyone's found a definite pattern to the way we naturally order words when listing items. While it doesn't work for some pairs, most of the time there's an obvious preference in the order.  Some examples:   Always "mom and dad" not "dad and mom" Always "grandma and grandpa" not "grandpa and grandma" Always "cars and trucks" not "trucks and cars"   The presence of a plosive doesn't seem to be the only factor:   Always "male and female" not "female and male" Always "good and bad" not "bad and good" (although this example feels less strict) More often "keyboard and mouse" than "mouse and keyboard" (also not super strict)   While there seems to be a general pattern of the plosive-heavy word being placed last, there are those examples which would serve to discredit such a hypothesis. Is there a known rule for this?


how to name templates for same content types

I have a Content Type machine name as "aktionsblock_oben" and made some content and get the Content ID as 33 for this one. Now I can use template name as page--node--33.html.twig, but what if I create new content like this where I get another ID? The page--node--33.html.twig won't fire.  My try page--node--aktionsblock_oben.html.twig or aktionsblock_oben.html.twig was a failure.  Any suggestions


Let $S$ be the collection of all groups. Deﬁne a relation on $S$ by $G \sim H$ iﬀ $G ≈ H$. Prove that this is an equivalence relation. So $S$ is partitioned into isomorphism classes.   Proof: Let $S$ be a relation on S defined by $G \sim H$ iﬀ $G ≈ H$. Show reflexive, symmetric, transitive. It is obvious that $G≈G$ so $G\sim G$.  Assume $G\sim H$, thus $G≈H$, which implies that $H≈G$, so $H\sim G$, thus symmetric.  Assume $G\sim H$ and $H\sim K$, for $K$ a group in $S$. Thus $G≈H$ and $H≈K$. (I have already shown that if $G≈H$ and $H≈K$, then $G≈K$). From earlier this implies that $G≈K$, so $\sim$ is an equivalence relation.  Thus $S$ is partitioned into isomorphism classes. QED.


What kind of behaviour causes an interrupted exception?

I'm relatively new to Threading in Java and I've noticed that everytime I use Thread.sleep() I have to catch InterrupetdException.  What kind of behaviour causes this, and in simple applications where I have a monitor thread can I just Ignore the exception?


What's the cardinality of all sequences with coefficients in an infinite set?

My motivation for asking this question is that a classmate of mine asked me some kind of question that made me think of this one. I can't recall his exact question because he is kind of messy (both when talking about math and when thinking about math).   I'm kind of stuck though. I feel like the set $A^{\mathbb{N}} = \{f: \mathbb{N} \rightarrow A, f \text{ is a function} \}$ should have the same cardinality as the power set of A, if A is infinite. On the other hand, in this , it is stated that the sequences with real coefficients have the same cardinality as the reals.   It's easy to see that $A^{\mathbb{N}} \subseteq P(A)$, but (obviously) I got stuck on the other inclusion. Is there any general result that says anything else? References would be appreciated.  EDIT To clarify the intetion of this question: I want to know if there are any general results on the cardinality of $A^{\mathbb{N}}$ other that it is strictly less than that of the power set of A.   Also, I was aware that the other inclusion isn't true in general (as the post on here I linked to gave a counterexample), but thanks for pointing out why too. :)


Ubuntu 12.10 desktop/interface not showing on VirtualBox VM after login screen

I'm having some trouble with getting my Ubuntu to work on a VirtualBox VM. I made a clean installation of Ubuntu 12.10 on a VM without any errors. I arrive at the login screen, as soon as I press enter it does it's little loading thingy and then screen goes black, then this is all I get:    I can access the terminal and pretty much all the other features through it, but I would like to have the GUI properly working. I've been looking around the web and looking at various fixes to similar problems, but can't seem to get it to work. I'm thinking this problem might have to do with the graphics?  I'm running Windows 8 Pro as host, if that helps, might be some compatibility issues with VirtualBox in W8...  Thanks in advance!


Choosing research ideas to include in a statement of purpose

The internet is littered with information on what makes a good SOP, but I would like to ask a specific question regarding mentioning one's research interests in SOP.  What points should a student keep in mind while writing her statement of purpose? If there is exactly one specific professor the student is targeting, it makes sense to talk of one of his recent papers and ideas for extending its results in the SOP.    If 1) there are a couple of preferred professors or more, 2) each of them has multiple research interests and 3) the student is unable to zero in on a field or topic, how should the student tailor her SOP to make it appealing to more than one professor? Should the student worry about the feasibility of her ideas in the SOP? Is an extensive literature survey in the relevant field necessary before putting anything in the SOP?


Generating functions and integer partitioning

Show that the number of partitions of a positive integer n where no   summand appears more than twice is equal to the number of partitions   of n where no summand is divisible by 3   So I begin by formulating this problem in terms of generating functions. Let $a(n)$ be the number of partitions of $n$ where no summand appears more than twice and let $b(n)$ be the number of partitions of $n$ where no summand is divisible by $3$.  If I showed that the $a(n)$ and $b(n)$ have the same generating functions then I am done, right ?  Now the generating function for $a(n)$ is $(1+q +q^2)(1 + q^2 + q^4)(1+q^3 + q^6).... = \prod_{i=1}^{\infty} (1 + q^i + q^{2i})$  But now I am stuck here, How can I get the generating function of $b(n)$ ? and how would I show that the generating function of $a(n)$ is the same generating function as $b(n)$ ?


So it seems that my java program is not able to recognize two identical objects even though I'm using the same method as in a previous question where java did recognize the two objects as being the same. The only difference in this program is I have an extra keyboard.nextLine() which is necessary for inputting the name/address of object two.  Here's the class input      public boolean equals(Person num1) {     if ((this.name==num1.name)&&(this.address==num1.address)&&     (this.age==num1.age)&&(this.phoneNumber==num1.phoneNumber))         return true;     else         return false; }   Here's the demo input     import java.util.Scanner;    public class PersonDemo {     public static void main(String[] args) {      Person num1, num2;     num1=new Person();     num2=new Person();      String name, address;     int age;      long phoneNumber;      Scanner keyboard = new Scanner(System.in);      System.out.println("Input the name of person 1:");     name=keyboard.nextLine();     System.out.println("Input the address of person 1:");     address=keyboard.nextLine();     System.out.println("Input the age of person 1:");     age=keyboard.nextInt();     System.out.println("Input the phone number of person 1:");     phoneNumber=keyboard.nextLong();     keyboard.nextLine();      num1.setName(name);     num1.setAddress(address);     num1.setAge(age);     num1.setPhoneNumber(phoneNumber);      System.out.println("\nInformation of person 1: ");     System.out.println(num1);      System.out.println("\nInput the name of person 2:");     name=keyboard.nextLine();     System.out.println("Input the address of person 2:");     address=keyboard.nextLine();     System.out.println("Input the age of person 2:");     age=keyboard.nextInt();     System.out.println("Input the phone number of person 2:");     phoneNumber=keyboard.nextLong();      num2.setName(name);     num2.setAddress(address);     num2.setAge(age);     num2.setPhoneNumber(phoneNumber);      System.out.println("\nInformation of person 2: ");     System.out.println(num2);      if (num1.equals(num2))         System.out.println("\nPerson 1 and person 2 are identical.");     else          System.out.println("\nPerson 1 and person 2 are not identical."); }      }


I apologize for the simple question.  We have the text:     We will close this ticket, please reopen it or create new one if anything will be unclear or if you will have more questions.   But in my opinion it should be create a new one instead of create new one after taking a look at  post also.  Am I right? Which one is grammatically correct?  Thank you for your interest and time.


Should the pronoun "you" always take a plural verb?

I'm writing a song, and I'd like to know if the pronoun "you" should always take a plural form. I wrote these two lines: It's You who never lies It's You who purifies I think it sounds wrong to say, "It's You who never lie." The subject "it" is singular, and "You" refers to one person, so maybe the s-form is correct?


MYSQL + PHP : "error in SQL syntax" when updating table using array and variables

I am a new developer and am trying to update a MYSQL table with modified user data after accepting a cc payment. I have taken all the values that need to be updated or inserted into each table and it seems like the arguments are all correct... but the tables are not updating and I am getting the following error message:  Notice: Undefined variable: msqli in /home/ban50/public_html/app/return.php on line 74  Notice: Trying to get property of non-object in                      /home/public_html/app/return.php on line 74  Error No: 0 - MySQL error 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 '' at line 1   Query: UPDATE `users` SET membership_id='1', mem_expire='' WHERE username=Blev80 #0 {main}   The code that I am using is as follows:  This is the standard "straight forward" variables. The $_POST[] variables are those that I receive from the payment gateway as an (array):  $host="localhost"; // Host name  $dbusername="Blev80"; // Mysql username  $password="MYPASS"; // Mysql password  $db_name="Blev80DB"; // Database name  $tbl_name="users"; // Table name  $mname=$_POST['li_0_product_id']; //membership/product ID $appusername=$_POST['username'];//Users "Username" $amch = $_POST['li_0_price']; //purchase price $amtot = $_POST['total']; //total price $curr = 'USD'; //currency $muid = $_POST['userid']; // USER ID   I then am trying to insert the END DATE of the purchase - I thought to use the strtotime (+ 1 month ) logic here:  $duration = $_POST['li_0_recurrence']; //recurrence calculation $eDate =strtotime('+$duration'); //the END date of the purchase $memexpire = $eDate  ; // my reference for the table (this may be a redundant step but it helps me to think in this way   for testing purposes I echo'd the End Date:  echo $eDate;   I ASSUME the above is working but I cant verify whats going on yet since I seem to have a problem in the code below:  $data = array(               'txn_id' => time(),               'membership_id' => $mname,               'user_id' => $muid,               'rate_amount' => $amch,               'tax' => '0',               'coupon' => '0',               'total' => $amtot,               'ip' => $_SERVER['REMOTE_ADDR'],               'date' => "NOW()",               'pp' => "2CO",               'currency' => 'ZAR',               'status' => 1);  if ($_POST['credit_card_processed'] === 'Y') {    //connect to DB    $mysqli = new mysqli("$host", "$dbusername", "$password", "$db_name");   //build queries   $query = "UPDATE `users` SET membership_id='$mname', mem_expire='$eDate'  WHERE username=$appusername";  $mins = "INSERT INTO payments ($data)";   //run queries   $mysqli->query($query);  $mysqli->query($mins);   //error checking   if ($mysqli->error) { try {         throw new Exception("MySQL error $mysqli->error
 Query:
 $query", $msqli->errno);     } catch(Exception $e ) {     echo "Error No: ".$e->getCode(). " - ". $e->getMessage() . "
";     echo nl2br($e->getTraceAsString()); } }  else { echo "Thanks database updated"; }   } else { echo "Credit card payment failed"; }`   So I have 2 issues  1) The error notice on line 74 references my error checking component  throw new Exception("MySQL error $mysqli->error
 Query:
 $query", $msqli->errno);   2) Something is wrong with the MYSQL syntax and the tables are not updating.   I have tried enclosing the table references in backticks, but I still get the message. I have tried changing the mysqli->error to mysqli(error) I have been to numerous SO questions and answers and have incorporated code where it seems to be necessary   --  I honestly don't know what else to try - I have been looking at the same 80 lines of code for 2 days now :)  Any help or feedback would be hugely appreciated!


Show that any complex roots must occur in conjugate pairs.

Let $p(\lambda)=c_0 + c_1\lambda + \dots + c_n\lambda^n$ be a polynomial with real coefficients. Show that any complex roots of $p(\lambda)=0$ must occur in conjugate pairs, i.e. if $p(\alpha+i\beta)=0$ then $p(\alpha-i\beta)=0$.  So I am kind of having trouble doing this for a general expression. Where should I start? I'd be able to figure it out for some small fixed $n$... Any hints would be helpful


Why can not be counted the pipe chars in string?

select Values, REGEXP_COUNT(values,'|') from Products    Sample Values cell:   Product|Cash|Loan|Customer   Result of select is 27. If count any other char it works, but if I want to count the | it counts the whole string. Why, and how can I count the pipes?


Easy mysql question regarding primary keys and an insert

In mysql, how do I get the primary key used for an insert operation, when it is autoincrementing.  Basically, i want the new autoincremented value to be returned when the statement completes.  Thanks!


How to prove limit of measurable functions is measurable

I need help to prove the following theorem      Suppose $f$ is the pointwise limit of a sequence of $f_n$, $n = 1, 2, \cdots$, where $f_n$ is a Borel measurable function on $X$. Then $f$ is Borel measurable on $X$.   My idea is to use the standard definition like for every $c$,$\{x:f(x)<c\}$ is Borel measurable. But got stuck as how to do it for sequence of $f_n$.


I saw this in the end of an awesome shell script but I can't understand the login here because I think it's being short-handed for a longer command.  spark ${@:-`cat`}   This apears at the end of . Any ideas?  + Marks for some one who extends it into a full segment of code, even if its slower (Better for explanation)


Align columns correctly in multicolumn environment

I have the following table:  \documentclass[a4paper,11pt]{report}  \usepackage[english]{babel} \usepackage{booktabs}  \begin{document}     \begin{tabular}{|cc|ccc|}         \hline         \multicolumn{2}{|c|}{Parameters} & \multicolumn{3}{|c|}{This is some long text about precision and recall}\\         \hline         n & p &S& P & R\\         \hline         3000 & 0.5 & 3000 & 0.01 & 1.00\\     3000 & 0.1 & 3000 & 0.01 & 1.00\\     3000 & 0.008 & 30 & 1.00 & 1.00\\     \hline     \end{tabular}  \end{document}     As you can see the variables S, P and R are not aligned correctly. I want them each to take the same space. How can I do this?


Prove that $A$ is bounded operator on $\ell^p$ and find $\| A\|$

For which one $p \ge 1$ is with $$A(x_n)_{n=1}^{\infty}=\left(\frac{1}{m}\sum_{n=1}^{m}\frac{x_n}{\sqrt{n}}\right)_{m=1}^{\infty}$$ defined bounded linear operator $A:\ell^p \to \ell^p$? Find norm $\| A\|.$   First, I have to show that if $x = (x_n)_{n=1}^{\infty} \in \ell^p$ then $\displaystyle y=(y_m)_{m=1}^{\infty} \stackrel{\text{def}}{=}\left(\frac{1}{m}\sum_{n=1}^{m}\frac{x_n}{\sqrt{n}}\right)_{m=1}^{\infty} \in \ell^p$, that is $\displaystyle\sqrt[p]{\sum_{m=1}^{\infty}|y_m|^p} < +\infty.$  All right, $$\begin{align*} |y_m|=\left|\frac{1}{m}\sum_{n=1}^{m}\frac{x_n}{\sqrt{n}}\right|&\leq\frac{1}{m} \sum_{n=1}^{m} \frac{|x_n|}{\sqrt{n}}\\ &\stackrel{\star}{\leq}\frac{1}{m} \sqrt[p]{\sum_{n=1}^{m}|x_n|^p} \sqrt[q]{\sum_{n=1}^{m} n^{-q/2}} \\ &\leq \frac{\| x \|_p}{m}\sqrt[q]{\sum_{n=1}^{m} n^{-q/2}}.\end{align*}$$  So $$\begin{align*} \sum_{m=1}^{\infty} |y_m|^p &\leq \sum_{m=1}^{\infty} \left|\frac{\| x \|_p}{m}\sqrt[q]{\sum_{n=1}^{m} n^{-q/2}}\right|^p\\&=\sum_{m=1}^{\infty} \frac{1}{m^p} \| x\|^p_p \left(\sum_{n=1}^{m} n^{-q/2}\right)^{p/q}\\ &\leq \|x\|^p_p \sum_{m=1}^{\infty} \frac{1}{m^p}   \left(\sum_{n=1}^{\infty} n^{-q/2}\right)^{p/q} \end{align*}$$  If I see well, last sum is convergent for $q/2 >1 \iff q>2$ and $p>1$ (but with condition $1/p + 1/q =1$).  I think my estimate is too sharp.  And we find that $$\| A \| \leq \sqrt[p]{\sum_{m=1}^{\infty} \frac{1}{m^p}   \left(\sum_{n=1}^{\infty} n^{-q/2}\right)^{p/q}}$$  But for part (if my approximation is good enough) with $\geq$ I don't have idea (to be honest, I used Hölder inequality, so we want $x_n = c  \frac{1}{\sqrt{n}}$, that will give us something divergent I think so).  $\star$ - one doubt also: I used here Hölder inequality, but that works only for $p,q >1$, but in my question we have $p \geq 1$, so basically I have to work case $p=1$ as separate?


I have a huge file  which contains BGP updates in the following fashion :  BGP4MP|1043481872|A|64.200.199.3|7911|217.72.176.0/20|7911 8272 16102 16102 16102|IGP|64.200.199.3|0|0|7911:999 7911:7211|NAG||   Basically, it is derived from using the route_btoa function.  I want to plot a graph based on the 2nd and 3rd fields of this line (you can ignore everything else). The 2nd field indicates time and the third field indicates if it is an Announcement (A) or Withdrawal (W) - these are the only two cases.   The graph is supposed to have as X-axis the time and Y-axis will be the number of BGP (A) - we ignore W-  updates at that time.  If anyone could help me plot this, that would be a great help! Thanks.


Proving that kernels of evaluation maps are generated by the $x_i - a_i$

I want to prove that the kernel of the evaluation map $s_a : \mathbb{C}[x_1,\dots,x_n] \rightarrow \mathbb{C}, x_i \mapsto a_i$ where $a = (a_1,\dots, a_n) \in \mathbb{C}^n$ is the ideal generated by $\{x_1 - a_1, \dots, x_n - a_n\}$.    The proof in the book first shows it easily for the case $a = 0$, and says that by substitutions of variables $x_i' = x_i - a_i$, you can show it for the rest of the cases.  I know that $f \in \ker s_a$ iff $f(a) = 0$.  And $\phi : \mathbb{C}[x_1,\dots, x_n] \rightarrow \mathbb{C}[x_1 - a_1, \dots, x_n-a_n], x_i \mapsto x_i - a_i$ is a surjective ring homomorphism.  Please give a hint and not the full answer.  Thanks.


Evaluation of Integral $ \int \sqrt{\sin x}\; dx$

Evaluation of Integral $\displaystyle \int \sqrt{\sin x}\; dx$  $\bf{My\; Try::}$ Let $\sin x = y^2\;, $ Then $\displaystyle \cos xdx =2ydy\Rightarrow dx = \frac{2y}{\sqrt{1-y^4}}dy$  So $\displaystyle \int \sqrt{\sin x}\;dx = 2\int \frac{y^2}{\sqrt{1-y^4}}dy = 2\int y^2\cdot \left(1-y^4\right)^{-\frac{1}{2}}dy$  (Using Wolframalpha It Show The Results is in the form of Elleptical Integral of first and Second Kind.)  Now How Can I solve after that   Help Required  Thanks


Cronjob doesn't execute shell script, but when I am executing it standalone it works. Why?

Shell Type:  >echo $SHELL /bin/ksh   Cronjob :   15 * * * * /bin/ksh /wls_domains/resMGT/logs/bea/wlr3queuetransaction.sh > /wls_domains/resMGT/logs/bea/data/script.log  The script is as below:  ##log files and lookup file "wlr3queue.txt" are in the same path of the script ##/wls_domains/resMGT/logs/bea/wlr3queuetransaction.sh  Script :  #!/bin/ksh  dt=`date +%Y-%m-%d` xy=`date|awk '{print $4}'|awk -F":" '{print $1}'` yz=`expr $xy - 1` if [ $yz -le 9 ] then yz=0$yz fi  if [ $xy -gt 0 ] then  for i in `cat wlr3queue.txt` do  sum=0  count=`gzgrep -i "$dt" admin_resMGT_access.log* | grep "$yz:[0-5][0-9]" | grep "$i" | wc -l`  if [ $count -gt 0 ] then name=`echo $i | cut -d'/' -f3`  gzgrep -i "$dt" admin_resMGT_access.log* | grep "$yz:[0-5][0-9]" | grep "$i" | awk '{print $8}' > consumed_time.txt  for j in `cat consumed_time.txt` do j_ms=`echo "$j * 1000" | bc` echo $j_ms >> consumed_ms_time.txt done  for k in `cat consumed_ms_time.txt` do sum=`echo "$sum + $k" | bc` done  avg=`echo "scale=2; ($sum/$count) "| bc`  min=`cat consumed_ms_time.txt | sort -n | head -1`  max=`cat consumed_ms_time.txt | sort -n | tail -1`  else  avg=0  min=0  max=0  fi ( echo $yz","$count","$avg","$min","$max )>>/wls_domains/resMGT/logs/bea/data/$name$dt.csv   rm -f consumed_ms_time.txt  done  else  echo "script won't execute at this hour" > temp.txt  fi   I have executed the following commands and the script ran successfully.  ./wlr3queuetransaction.sh sh -x wlr3queuetransaction.sh /bin/ksh /wls_domains/resMGT/logs/bea/wlr3queuetransaction.sh  /bin/ksh/ wlr3queuetransaction.sh.   How to debug? What to do?


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


Why doesn't current pass through a resistance if there is another path without resistance? How does it know there is resistance on that path? Some clarification:  I understand that some current will flow through the resistance. A depiction of this phenomenon through Ohm's laws does not answer the 'why' part of the question as it does not illuminate the process behind this phenomenon. There seems to be disagreement among the answers on whether the charge repulsions are enough to cause this effect. Cited research would be appreciated to resolve this issue. To refine what I mean by this question, I think I should give an example of why I am curious as to the causal background of this phenomenon. If charge repulsions do in fact repel 'current' in the example of the short circuit, then why does the same phenomenon not happen in other parallel circuits. (Again, I know that not all circuits behave ideally) I believe the question is expressed in the most straightforward way possible. This should, however, not affect the scope of the answers. I do not wish to see or think on the level of an electron as circuit behavior always includes a cumulative effect due to the nature of electrostatic interactions.


Living in Florida working remotely - NY employer withholds NYS taxes - Correct or Incorrect?

This question has been asked before but the answer was inconclusive.   Moving to Florida was my personal decision. My employer agreed to let me continue in the same job working remotely.  NYS tax for the 2015 was withheld by my employer but unemployment insurance was paid to FL. Is this correct or incorrect?


If someone calls me brother-in-law , what are they to me? A girl called me brother-in-law , what is she to me? A girl who calls me brother-in-law , what should I call her?


How to center an image in the middle of a div?

I need to center an image in a middle of a div.  <div class="main">     <img...> </div>   In the example below the image is centered, but not in the middle.


Perfboard/Stripboard insulation techniques and what material to use

I most often make circuits on perfboard. Below is an example of a circuit, both bottom and top sides:      This circuit will be in a case but outdoors for many months. In case of some rain leakage or humidity or rust ect, I want to protect this circuit by isolating it.  I saw some people use an epoxy like thing in both sides. I couldn't find any detailed information in my search.  I'm totally ignorant about this. What kind of material should I use and should I pour and cover it both sides?


I have created fields deleted them. Tables for the fields are gone upon deletion, but they are still in field_config and field_config_instance  Is there anyway to clean them?  Thanks


Show that the following set is closed.  $$ S_n = \{ A \;\epsilon \; \mathbb R^{n^2} | \text{A is symmetric} \} \,\subset\, \mathbb R ^{n^2}$$  We are given a hint to use this theorem: Let f be a function from $\mathbb R^n \, to \,\mathbb R^m$ Then, f conts $\iff f^{-1}(F) $ is closed for each closed set F in $\mathbb R^m$.  Not sure where to even begin. Thanks!


Java - Looping through ArrayList to scan for matching value

I'm trying to write a simple program using an ArrayList that adds values, removes values, and prints values. However, I'm having an issue with removing values that the user inputs. The user should input a designated amount of values (determined by the user) and then the program should remove those values (if there are duplicates then it should just remove the first instance of the number which is fine). It's not removing the values and in some cases removes one value. I'm a bit confused as to where my code is bugged. Here is my code for remove values:  private static void removeVals() {         System.out.println("How many values would you like to remove?");         int amountToRemove = scanner.nextInt();         scanner.nextLine();         System.out.println("Enter " + amountToRemove + " values:");         for(int i = 0; i < amountToRemove; i++) {             int vals = scanner.nextInt();             if(arrayList.get(i).equals(vals)) {                 arrayList.remove(i);             }         }         System.out.println("Values removed");     }   And here is my full code:  public class Main {      private static ArrayList<Integer> arrayList = new ArrayList<Integer>();     private static Scanner scanner = new Scanner(System.in);      public static void main(String[] args) {         printOptions();          int option = scanner.nextInt();         while (option != 0) {             switch(option) {                 case 1:                     addVals();                     printOptions();                     option = scanner.nextInt();                     break;                 case 2:                     removeVals();                     printOptions();                     option = scanner.nextInt();                     break;                 case 3:                     printVals();                     printOptions();                     option = scanner.nextInt();                     break;                 case 4:                     printOptions();                     printOptions();                     option = scanner.nextInt();                     break;                 default:                     System.out.println("Not a valid option, please enter again:");                     option = scanner.nextInt();                     break;             }         }     }      private static void addVals() {         System.out.println("How many values would you like to add?");         int amountToAdd = scanner.nextInt();         scanner.nextLine();         System.out.println("Enter " + amountToAdd + " values:");         for(int i = 0; i < amountToAdd; i++) {             int vals = scanner.nextInt();             arrayList.add(vals);         }     }      private static void removeVals() {         System.out.println("How many values would you like to remove?");         int amountToRemove = scanner.nextInt();         scanner.nextLine();         System.out.println("Enter " + amountToRemove + " values:");         for(int i = 0; i < amountToRemove; i++) {             int vals = scanner.nextInt();             if(arrayList.get(i).equals(vals)) {                 arrayList.remove(i);             }         }         System.out.println("Values removed");     }      private static void printVals() {         for(int i = 0; i < arrayList.size(); i++) {             System.out.print(arrayList.get(i) + " ");         }         System.out.println();     }      private static void printOptions() {         System.out.println();         System.out.println("Program options: ");         System.out.println("1. Add values\n2. Remove values\n3. Print values\n4. Print options\n0. Exit\n");         System.out.println("\nWhat would you like to do? (enter an option):");     } }


Why would a chip manufacturer produce a 64-bit CPU which supports a maximum of 2 GB RAM?

My laptop uses an Intel Atom Z3735F processor, which the CPU specs on the Intel website indicate is 64-bit but only supports a maximum of 2 GiB of RAM. (The laptop came with Windows 10 32-bit pre-installed.) What is the point of having a 64-bit CPU which only supports 2 GiB of RAM? Does a 64-bit processor have any advantage beyond more conveniently supporting more memory?


What causes a recommend closure flag to be marked disputed, versus helpful or declined?

I know that this type of question was asked many time, but I didn't find answers related to my specific questions anywhere. At  it is explained about disputed flags of types NAA, VLQ, offensive and spam, by there is no mention about off-topic flags.  I found explanation that after triage review flags may get disputed, but it says that close votes are not affected.  So here is my questions:   In which cases exactly off-topic flag gets disputed? Also I have disputed flags in my profile near the questions that are actually [on hold], why my flag not appears helpful? Recently I marked  as off-topic, and now my flag is disputed. Is that mean that flag was inappropriate and question should remain in the developers SO? Does flag counts as helpful if it describes the reason to close not very accurate? For example if I marked question as off-topic, but it was put on hold as too broad


Do Legendary Pokemon Respawn After The Elite Four?

I've heard that legendary Pokemon such as Kyogre/Groudon respawn after you defeat the Elite Four (if you didn't catch them). The only information that I can find seems to relate to the original version of the game.  Can players faint legendary Pokemon in order to progress the story and come back later to capture them? And are there any exceptions?  The reasoning for this is some players, myself included, wish to finish the game in order to unlock post-game features before investing time/effort soft resetting for ideal natures in legendary Pokemon.  Please avoid spoilers where possible.


How can I safely remove the ~/Snap folder?

I'd love to delete the Snap folder in my home. It takes 97 GB of space. No package manager should be allowed this amount of space in the /home mount point!  How can I safely delete Snap and all its content (without breaking dependencies)?  I am really not interested in hiding or moving the Snap folder. I wish to delete it and remove the package that is responsible for it. Really I was happy enough with aptitude.


How to tell the maximum speed of copying a file using Finder or cp or rsync?

I got a Samsung T7 SSD drive knowing that it can handle 1GB/s read or write, but if I used  rsync -a --progress --stats --human-readable file1.m4v /Volumes/T7/file1.m4v   to tell the speed of copying a file, it only can go up to 180MB/s or at most 220MB/s (and cp feels slow as well).  But if I open up two Finder windows and drag and drop the file over, it really feels like 5 seconds to copy a 5GB iTunes movie file. (I then used a stopwatch to find out copying 16.5GB needed about 19 seconds).  (I think why the UI drag and drop can copy so much faster is due to rsync or cp using one processor core, and it is limited to one core's speed.)  So if I use the UI's drag and drop way of copying, is there a way to tell the copy speed? Or alternatively, if I use any command in Bash, can it copy a file at the maximum speed of the SSD and be able to tell the speed?


I would like to transfer files between two remote hosts using on local shell, but it seems rsync doesn't support synchronisation if two remotes are specified as follow:  $ rsync -vuar host1:/var/www host2:/var/www The source and destination cannot both be remote.   What other workarounds/commands I could use to achieve similar results?


$\neg (\neg A) \rightarrow A$ part of the axioms of propositional logic?

When talking with a mathematics teacher the other day, we discussed these axioms in the context of proving tautologies with semantic tableaux:   $(p\to(q\to p))$ $((p\to(q\to r))\to((p\to q)\to(p\to r)))$ $((\lnot p\to\lnot q)\to(q\to p))$   We wondered if it was possible to show that $\neg(\neg A) \rightarrow A$ from these axioms (along with MP), but it did not seem obvious how to do so and yet this fact is not included as an axiom. Is it provable from the axioms or is this fact simply unprovable in this version of PL?


"I play tennis everyday" or "I play tennis every day"?

.  But I saw a lot of people wrote "I play tennis everyday".   Is "I play tennis every day" the right way?


Blender doesn't use system resources optimally

let me just preface this by saying I am new to Blender and have a very minimal knowledge pf it as of now.  The problem happened as I was following along with a tutorial and while doing a cloth simulation, I was getting about 0.4 fps (this was my first time running an animation), I checked blender's usage of system resources via task manager and everything was under utilised, with blender using memory 6-7%, cpu 8-12%, gpu 2-4% and no other major applications running. I have looked for ways to make it use more of these resources but couldn't find any that made much difference, I did in the end get it to 2 fps but that was due to a post that said scaling small objects up makes blender process the simulation better. I am hoping someone here can tell me how to optimize blender to better use these resources. I am running the animation in viewport and solid shading, this isn't with regards to rendering speeds although even then the system resources remain under-utilised.  My specs:  Dell XPS 15 9560 | Windows 10 v. 1909 64-bit  GPU - Nvidia GeForce GTX 1050  CPU - Intel Core I&-7700HQ @ 2.80Ghz (8-core)  RAM - 32 GB  Please let me know if the information is incomplete.


In what order should a newcomer watch Star Wars episodes?

I have a friend who has never seen Star Wars and he wants to watch it.   I am unsure which order I should suggest. Should he watch the old or new Trilogy first? Or some kind of mixed order? I am looking for a well-reasoned answer, not one-liners.


how to iterates a hashmap, does it need to cast the keySet() in Java?

I have a question about iterate a hashmap:  Map<String, Integer> map = new HashMap<String, Integer>();   I want to iterate this hashmap and printout out the key and value pair using the following code:  Iterator iterator = portMap.keySet().iterator();   but it indicates me to cast the portMap.keySet().iterator(); to (Iterator)portMap.keySet().iterator();, but the iterator() return as a iterator already, why I need to cast it? And I checked some other code, there is no cast for the return value of iterator(), what is the reason, and how to fix it?


How do I insert a backslash inside a mathematical statement?

I'm trying to write a set subtraction operation in an AMS formatted template.  In the end, what I want should look like A\B.  But I'm doing this in math-mode $A\B$ and this gives me errors.  I've also tried using the \diagdown symbol, but it doesn't work either.  Is there another way to do this?


Why does the minimal polynomial in $\mathbb{R}[X]$ have to have degree less than or equal to $2$?

As I was reading , I saw Ethan's answer. However, perhaps this is very obvious, but why does the degree of the polynomial be at most $2$? I get that the polynomial must be irreducible but does that force the degree to be at most $2$?