70s or 80s Book. Post Catastrophe, Sheriff tries to hold town together, and keep his schizo wife from killing him

Its a year or two after Something has caused the collapse of society, Small towns are on their own.  One side effect (or maybe the cause) is a psychosis affecting many people that when they are triggered, they go into a murderous rage and kill people. Shortly later they snap out of it and are back to normal and have no memory of what happened. Society had devolved to the point that when the psychotics are identified, [usually IDed cause they just killed or tried to kill someone], they are just executed because no one knows what may trigger them, or has the resources to care for them if they lock them up.  The Protagonist is the town Sheriff/Police Chief. His wife is one of these Psychotics. But he has learned her trigger is Sex. (After Sex, she gets up, cooks a meal, and when he sits down to eat, attacks him). Now when she attacks him, he just locks her into the pantry or basement. (I think when she snaps out of her rage she is capable of unlocking the door again and goes back to being a normal housewife) Fortunately he lives a ways outside of town so townspeople don't visit.   Unfortunately, although rare, there are occasionally travelers along the road. When someone stops at the house when the Sheriff is at work, his wife psychosis causes her to seduce, feed and then attack and kill the traveler. So the Sheriff has a mess to clean he when he gets home.  He now has like 10-12 Graves (and abandoned cars/motorcycles?) along the road, to 'warn' travellers that stopping might be a bad idea.  The Mayor/Town leaders who know of her condition, are pressuring the Sheriff to get rid of his wife and move into town so he can better protect them from the roving gangs. (But he cant bring her to town, and does not want to kill her so he always refuses) The problem is, there are reports of a very large gang attacking nearby towns and heading to the town and the Mayor is starting to get desperate.  I mostly remember the beginning of the book, and little of the rest.  Pretty sure the book opens with the scene of the Protagonist waking up in the morning after having sex that night before and carefully going to eat breakfast in the kitchen. He is nearly surprised when his wife attacks him before he has eaten. But manages to subdue her and lock her in the pantry. [during or after this event is when the reader is filled in on whats happening] (He is nearly surprised because normally she attacks as they finish eating and she gets up to wash the dishes at the sink behind him)  The other scene I recall The Protagonist is talking to (The Mayor?) who mentions he hears there is another Car/Motorcycle/Grave in front of his house. Isn't that like the 12th(13th,14th?) one now. The Protagonist says yes, but its no one from town, so quit bugging him about it. We've had this discussion before, I'm not killing her, and if you try to force it, I will quit. But the mayor knows the Protagonist is VERY capable, and has been whats been holding the town together so just drops it.  I 'think' if I remember correctly the wife, who has now gone through the psychotic episodes 40-50 times now, is starting to realize something is seriously wrong (either flashbacks, or "waking up" in the pantry to many times) and is asking her husband about it. Which gives him hope maybe it can be reversed or cured.   Book was almost certainly a US mass market paperback.


If my Mac is connected to ethernet and WiFi, which will it use?

As per title. I have ethernet issues at home and if I just turn WiFi on my MacMini, will this take over or will it default to ethernet unless I pull the cable out?


Adding n different lists to list results same list repeating


Is it the magnetic or electric components of light that get polarized?

Since polarization filters light in all directions except one, the electric or magnetic field should be filtered, right?


How to reset shortcuts (.lnk file)  in Windows 7?

Somehow I went to open a shortcut and Windows couldn't find the target but instead of pointing the shortcut to the .exe it pointed the .lnk file handler to the .exe, so now all my .lnk files are trying to be opened by the borderlands game.  What's going on?  I'm guessing I can do it by resetting the .lnk entry in HKEY_CLASSES_ROOT, but I don't know what to set it to.


Install Java 1.4.2 on recent Amazon Linux

I need Java 1.4.2 on a up-to-date Amazon Linux 2015.09 server. I've tried to install j2sdk-1_4_2_19-linux-ia64-rpm.bin. When I execute this file, I get an error message:  line 442: ./install.sfx.12314: cannot execute binary file   Maybe I'm doing this the wrong way. I downloaded the binary from Oracle, where I see that the most recent Linux (non Solaris) version is Java SE Development Kit 1.4.2_19:     Java SE Development Kit 1.4.2_19  31.69 MB    j2sdk-1_4_2_19-linux-ia64-rpm.bin Java SE Development Kit 1.4.2_19  32.64 MB    j2sdk-1_4_2_19-linux-ia64.bin   Uname -a shows this:  Linux 4.1.17-22.30.amzn1.x86_64 #1 SMP Fri Feb 5 23:44:22 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux   I've tried both bin files, and both report the same error.   How can I install Java 1.4.2 on this machine?


A mathematics career but a journalist-ic career?

My question pertains to the rules, and more specifically the ostensible violation of the rules on the modification of nouns into adjectives. I sometimes experience difficulty of knowing when to adjective-ify nouns when (1) the adjective immediately precedes the noun in question and (2) the adjective version of the noun exists and is spelled differently. Take the two examples I came across, surfing on the web: a) "A journalistic career" b) "A mathematics career" Both phrases convey the same relative semantic idea and an almost identical construction bar one detail : in (a) the adjective version of journalist is deployed however in (b) the noun form of mathematics is left unaltered even though it functions as an adjective. The adjectival form of mathematics is obviously mathematical. Is there a rubric or custom to distinguish when to adjective-ify nouns in these contexts? Or is it completely optional and both camps are valid? Edit: another illustrative example : Is it correct to say "a gallery of cow pictures" or "a gallery of bovine pictures"? Edit: My question is about the broader use and abuse of adjectives beyond the examples listed. Is there a hard-and-fast rule?


Has anyone tried installing blender on a Raspberry Pi 3 or do you know which version of blender will be supported on Pi3? If I get just the 3d view running for modeling, that'll be great.


Novadays it is very hard to study with an unstable computer.  I had my laptop for about 5 years and a year ago I installed Ubuntu alongside Windows (which I never used). I had no problems for about a year, but two weeks ago my computer boot to initramfs.   Simple solutions like "just type 'fsck /dev/sda1' " didn't work so first time I reinstall Ubuntu (and deleted Windows). But after a few days the problem came back. So, I learned, how to fix problem with live CD (based on ). But the problem appears again and again after about 3 days.   Today I couldn't boot Ubuntu.  So, my question is: "What can cause Ubuntu to boot in initramfs so often? How can I avoid surprises again?"


How do I change TinyMCE button "i" to create a i tag rather than em?

I want to give the "italic" button back the "styling" behaviour, rather than the spammy <em>. I want that button to print a <i> tag, rather than <em>.  <em> tags became popular to spam search engines, but now I want it to be what it is: a styling feature to e.g. change the voice of the narration.  I've got a script to create my own styles, so I'll include the <em> tag there, to use it as what it REALLY is: EMPHASIS. I'll then style it accordingly (big, bold).  So now my problem is, I'm sure I can find the setting / string / parameter to hack in JavaScript, but... Do you know a way to hook it from / for WordPress?


I have a B1/B2 visa to US, can i stay in US as a citizen and for how long?Can i apply for jobs there in US on this visa? What are the chances to get a job there?  Can i apply for an H1-B visa while my stay in US on B1/B2 visa?


How to prove that $\displaystyle f''(a)=\lim_{h \to 0}\frac{f(a+2h)-2f(a+h)+f(a)}{h^2}$

Let $f:U\longrightarrow \mathbb{R}$ where $U\subset\mathbb{R}$ open set and $f$ twice-differentiable in $a\in U$.  How to prove that $$f''(a)=\lim_{h \to 0}\frac{f(a+2h)-2f(a+h)+f(a)}{h^2}$$   without using Taylor or L'Hopital's rule.   Any hints would be appreciated.


Birthday line to get tickets in a unique setup

There is a long line of people waiting outside a theatre to buy tickets. The theatre owner comes out and announces that the first person to have a birthday same as someone standing anywhere before him in the line gets a free ticket. Where will you stand to maximize your chance?


how to prevent cell color to cover table's borders?

When I change the background color of a cell in a table, the color covers the borders, however I want the horizontal lines to remain.  I have a simple command \cellcolor[gray]{0.9} in my table. Can anybody help me with this problem?


Setting default ubuntu desktop backgrounds

How to change the default desktop background? A list of background pictures are available in the preference window, but I want to make my own picture as a default wallpaper. What can i do?


Is there any device that enhances the USB signal?

I want to make a USB cable of 20 meters and that this is able to deliver 500 mA and keep the voltage at about 5V stable.  I have been testing several solutions, such as connecting a self-powered USB hub on the end of the cable.  I would like to know if there is any device—PIC or something similar—that can perform the same function of a hub, but that is more economical.  A diagram for the cable could be:     USB Connection on a PC <-----------> Repeater <-----------> Cable End   What could I use to achieve this?


Book about teaching magic and an old stone

It's been more than ten years, but I've been thinking about a book I read as a kid. I can't remember any part of the title or author's name.   It begins with an old man who sits and ponders a stone in his hand constantly, which he's worn smooth. He takes on a boy or young man and teaches him the secret of magic by giving him progressively more physically difficult chores. The boy finally gets it when he's told to move an impossibly large boulder, but ends up yelling at it to move, which it does.   I remember that there were others who were taught magic, and the stone turns out to be some sort of magic orb, maybe a fallen star. These magicians are able to change into animals. It was a longer book, at least 700 pages. Hope someone can help...


There are $10$ commutative rings of order $8$

I have read that there are $10$ commutative rings of order $8$ (in this question, rings are unital and associative by definition), but I haven't found a concrete list of them.  But I think that they are the following:   $\mathbb{F}_2 \times \mathbb{Z}/4$ $\mathbb{F}_2 \times \mathbb{F}_2 \times \mathbb{F}_2$ $\mathbb{F}_2 \times \mathbb{F}_4$ $\mathbb{F}_2 \times \mathbb{F}_2[x]/(x^2)$ $\mathbb{Z}/8$ $\mathbb{F}_8$ $\mathbb{F}_2[x]/(x^3)$ $\mathbb{Z}/4[x]/(2x,x^2)$ $\mathbb{Z}/4[x]/(2x,x^2-2)$ $\mathbb{F}_2[x,y]/(x^2,xy,y^2)$   Can someone confirm this? Also, is there a direct proof that these are all?  Since rings of order $2$ and $4$ are easy to classify and every finite commutative ring is a direct product of local commutative rings, we may restrict our attention to local commutative rings of order $8$. These will be the last $6$ in the list.  The paper "Associative rings of order p^3" by Gilmer and Mott is not very specific about the proofs, and the paper "Finite associative rings" by Raghavendran is rather confusing for me. The papers also consider non-unital and non-commutative rings.  Edit. Here is a proof that these rings $R_1,\dotsc,R_{10}$ are pairwise not isomorphic. Probably it is not optimal, but for the moment it just works.   $R_1,\dotsc,R_4$ are not local, but $R_5,\dotsc,R_{10}$ are. $R_2,R_3$ are reduced, but $R_1,R_4$ are not. $R_1$ has characteristic $4$, but $R_4$ has characteristic $2$. $R_2$ has a trivial group of units, but $R_4$ does not. $R_5$ is the only ring of characteristic $8$. $R_6$ is the only field. $R_7,R_{10}$ have characteristic $2$, but $R_8,R_9$ have characteristic $4$. $R_{10}$ has a unique maximal ideal $\mathfrak{m}$ satisfying $\mathfrak{m}^2=0$, but the one of $R_7$ only satisfies $\mathfrak{m}^3=0$. $R_9$ contains a root of $2$, but $R_8$ does not, because $R_8/(x) = \mathbb{Z}/4$ does not.


What are the Download accelerators available for Ubuntu?  I like prozilla, but couldn't find a way to install it using apt or software center.


synaptics touchpad not working properly in Ubuntu 18.04

I am new to Linux the first thing which is bothering me is I can't use scroll down on my touch pad I have to drag the scroll bar manually. If anyone can help me  its a synaptics touchpad


Generating points for Sigmoid Function/Graph knowing only endpoints

If I have 2 end points how can I generate values for the Sigmoid function?


How do I replace the Linux Mint partition with Ubuntu without harming my Windows 10 partition?

I have a Linux Mint partition on my windows 10 laptop that a friend set up for me a while back to try Linux. Mint played weirdly with my system putting more strain on it than windows 10 did somehow so I just left it to sit there while continuing to use Windows.  I am interested in trying Ubuntu, but I can't just ask my friend to do it this time. I have been trying to look up tutorials or guides, but there are surprisingly few and the ones I have found imply it is easy to accidentally wipe out your windows partition.  I have a bare minimum of Linux knowledge. I have played around in Linux a tiny bit, and know how to use a bootable USB on a system that can just be wholesale overwritten. But when it comes to the partitions and how you would replace them it seems foreign to me.  If nothing else I'd like to find what resources would help someone who has no idea what they are looking at, and I apologize if this is written poorly. This is my first post on the forum.


I want to root a Galaxy S4, yea I know it's an old phone, but perfect for what I want to do. Problem is, once I do adb restart bootloader, the device is no longer on the adb devices list, so I cannot unlock the bootloader. Any suggestions? I am somewhat new at this so I don't know exactly what to do. Step by step would be nice.


Adding two numbers Android Studio, so simple project, but getting error

I'm adding 2 numbers and when click to Button - application crashes, and this error appears in Android Studio ---java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference  How can I solve it?  This is activity_main.xml file      <?xml version="1.0" encoding="utf-8"?>     <LinearLayout         xmlns:android="http://schemas.android.com/apk/res/android"         xmlns:app="http://schemas.android.com/apk/res-auto"         xmlns:tools="http://schemas.android.com/tools"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:orientation="vertical"         tools:context=".MainActivity">           <Button             android:id="@+id/btnAdd"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_marginBottom="250dp"             android:text="Add"             app:layout_constraintBottom_toBottomOf="parent"             app:layout_constraintEnd_toEndOf="parent"             app:layout_constraintHorizontal_bias="0.262"             app:layout_constraintStart_toStartOf="parent" />          <EditText             android:id="@+id/etNum1"             android:layout_width="250dp"             android:layout_height="wrap_content"             android:ems="10"             android:inputType="number"             app:layout_constraintEnd_toEndOf="parent"             app:layout_constraintStart_toStartOf="parent"             tools:layout_editor_absoluteY="112dp" />          <EditText             android:id="@+id/etNum2"             android:layout_width="250dp"             android:layout_height="wrap_content"             android:ems="10"             android:inputType="number"             app:layout_constraintEnd_toEndOf="parent"             app:layout_constraintStart_toStartOf="parent"             tools:layout_editor_absoluteY="267dp" />          <TextView             android:id="@+id/txtAnswer"             android:layout_width="250dp"             android:layout_height="wrap_content"             android:text="Answer:"             android:textSize="32dp"             app:layout_constraintBottom_toBottomOf="parent"             app:layout_constraintEnd_toEndOf="parent"             app:layout_constraintHorizontal_bias="0.895"             app:layout_constraintStart_toStartOf="parent"             app:layout_constraintTop_toTopOf="parent" />      </LinearLayout>   And this is MainActivity.java file   package com.naila.triangle;  import androidx.appcompat.app.AppCompatActivity;  import android.annotation.SuppressLint; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView;  public class MainActivity extends AppCompatActivity {      EditText num1;     EditText num2;     Button add;     TextView result;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          num1= (EditText) findViewById(R.id.etNum1);         num1= (EditText) findViewById(R.id.etNum2);         add= (Button) findViewById(R.id.btnAdd);         result= (TextView) findViewById(R.id.txtAnswer);          add.setOnClickListener(new View.OnClickListener() {              @Override             public void onClick(View v) {                 int number1 = Integer.parseInt(num1.getText().toString());                 int number2 = Integer.parseInt(num2.getText().toString());                 int sum = number1 + number2;                 result.setText("Answer: "+ sum);              }         });         } }


Proving $A \cap (B-A) = \emptyset$ (new to proofs!)

I'm a novice mathie - only calculus courses until this past semester, when I started Foundations of Mathematics (a bit of naïve set theory, introduction to basic proofs.)  Up to now, I have been able to complete proofs assigned by using parity, simple modular math, greatest common divisor, etc.  That being said, I am stuck on developing a proof for this.  Let $A$ and $B$ be sets. $A \cap(B-A) = \emptyset$.  The methods I have at my disposal are direct, contrapositive, and contradiction.  I would appreciate a gentle nudge in the right direction. This one has me stumped.


Prove directly from the definition of the Ito's integral

I am trying to solve the exercises from the book Stochastic differential equations -An Introduction with applications by Bernt Oksendal and I am stuck on 1 question.  Prove directly from the definition of Ito's integral that   $$\int_0^t B_s^2 dB_s=\frac{1}{3}B_t^3-\int_0^t B_s ds$$  I have tried for a couple of hours but I simply cannot prove it . I would be grateful if somebody could help me out , even a hint would be very helpful


A thought just hit my mind that whatever branch points I have seen to make some functions holomorphic are always isolated i.e. there exists a neighbourhood around them which contains no branch points.  So I thought whether they are always isolated?  I looked up for a proof and even thought over it but couldn't find a suitable approach.  So my question is whether branch points are always isolated?


At which threshold is unbalanced data a problem for a binary classification tree?

I want to build a binary classification tree to clasfiy wether a person is working or not and use the model for prediction. I read that unbalanced data could be a problem. Now i ask myself at which treshold is the unbalance big enough that it could yield to problems for the tree? Below you can see the table outputs for the variable to see how unbalanced the the variable is that i try to predict. I want build 2 trees for 2 different years. Is the data to unbalanced or is it okay?  > table(testSet2002$Partizipation)     0    1  1031 2229  > table(trainSet2002$Partizipation)     0    1  2361 5246  > table(testSet2015$Partizipation)     0    1  1040 2210  > table(trainSet2015$Partizipation)     0    1  2352 5265


What is the word for when you are about to walk into someone and hesitate whether to move left or right?

When you are about to walk into someone (generally a stranger), you anticipatory move, say left, to avoid a crash. The other person too does the same but to his right. So in essence the anticipation on both sides was futile (your left is his right). Then you go right and the other guy responds with a left. This carries on twice or thrice until it ends with a smile and a consensus as to which way to go. Finally you part ways.  This whole 'process' seems very intriguing to me and I'm sure has not just happened to me, hence, I expect there must be some word for it.


What are the differences between Lubuntu, Kubuntu, and Ubuntu?

Are Lubuntu, Kubuntu, and Ubuntu the same except for the desktop environment and a few programs?


Will pure Java written software be accepted in Ubuntu Software Center

I just came across an article regarding submitting app to Ubuntu Software Center    I'm currently maintaining a open source stock market software. I would say around 80% are Windows users, although the software itself can be executed in Linux too.  I would like to increase adoption of Linux users. Hence, distributing the software in most popular Linux distro will definitely help.  I was wondering, whether a pure Java written software will be accepted in Ubuntu Software Center? It requires JRE6 and above.


Is the word "beginning" here a gerund or a present participle?

Is the word "beginning" here a gerund or a present participle, and why?  On June 22, 1941, the armies of Nazi Germany crossed the Soviet border, beginning a war that would claim the lives of millions of soldiers and civilians alike.


Nonempty subset H of group G is subgroup iff $ab^{-1} \in H $ for any $a,b \in H$

Let $G$ be a group. Show that a nonempty subset $H$ is a subgroup of $G$ if any only if $ab^{-1} \in H $ for any $a,b \in H$.  The forward direction is quite easy. Suppose $H$ is a subgroup. Then by closure, $ab \in H$ for any $a,b \in H$. Every element has an inverse. Hence, if $b \in H $, then $b^{-1} \in H$. Hence, by closure again, $ab^{-1} \in H$.   Backward direction, suppose $ab^{-1} \in H $ for any $a,b \in H$. Let $a=b$. Then we have $bb^{-1}=1_H\in H$. Let $a=1_H$ , we have $1_Hb^{-1}=b^{-1} \in H$. I don't know how to show closure.  Reference: Fraleigh p. 58  Question 5.45 in A First Course in Abstract Algebra


We're hosting 10 websites with (most of them using Drupal 6 or Drupal 7) using nginx + php-fpm. Our VPS is low end (only 1GB of RAM with 64 bit OS and limited CPU). The amount of visitors is moderate to low, but simultaneous traffic in many of them is enough to get timeouts.  1) Is it correct to use php-fpm in this scenario, or it would be better to go back to Apache and mod_php?  2) Is it better to keep a fpm pool for each site, or in this extreme condition using one pool for many sites would make any difference? (Security issues aside)  3) Is there a formula for calculating the best values for pm.max_children, pm.start_servers, pm.min_spare_servers, pm.max_spare_servers and APC settings (enabled using default settings under Ubuntu 12.04 LTS)?  In general, any recommendations about running php-fpm with low resources would be greatly appreciated.


How to get a program written in C to execute a command in Terminal or Command Prompt?

I would like to write a program in C that can shutdown a computer. In order for me to do this, I must execute the command "shutdown -h now". This is to be done in the terminal or command prompt. How can I tell the program I would like it to execute the command in the command line?


I accidentally deleted files under /Library/Ruby/ and /System/Library/Frameworks/Ruby.framework/ folders. Now, is there any way to recover them or install fresh Ruby setup?


Show that $12n+5$ and $5n-2$ are relatively prime for all $n$ (in $\mathbb{Z}$) I've seen similar questions on here, I tried following their answers and doing it myself, but it's not working out for me. I tried the Euclidean Algo a few times and it's never ending. I'd be happy if someone could post the way to do this.


Use & (ampersand) in single line bash loop

I have been using this command successfully, which changes a variable in a config file and then executes a Python script within a loop: for((i=114;i<=255;i+=1)); do echo $i > numbers.txt; python DoMyScript.py; done  As each DoMyScript.py instance takes about 30 seconds to run before terminating, I'd like to relegate them to the background while the next one can be spawned. I have tried what I am familiar with, by adding in an ampersand as below: for((i=114;i<=255;i+=1)); do echo $i > numbers.txt; python DoMyScript.py &; done  However, this results in the below error: -bash: syntax error near unexpected token `;'


Travel time from Heathrow to King's Cross

What's the travel time, by tube, from Heathrow to King's Cross Station in London and how often does the tube run between those locations?


"Try to open the car" vs. "Try opening the car"

I have a few questions.    Do the following structures sound natural to native speakers?  Is there any difference in meaning between them?         Try to open the car.   Try opening the car.      You may notice that the two structures are in the imperative form. Have you ever used "Try to open.../ Try opening... that way? Or, do you just say "Open the car"?


Change GNOME terminal background color on fly

Is it possible to change the background (or window) color of open terminal window on Ubuntu GNOME environment? I would like to do this for tagging purpose when working with multiple terminals.


I have 2 questions   When to use "myself" and "by myself"   Can I write "my{space}self" instead of "myself"?


locate [file] but go to directory, it's not there

I am root. I have PHP webpage on Apache 2 server putting .stl files in /var/www/upload using move_uploaded_file( 'from', 'to' )   When I use locate, I see the file is in /var/www/upload When I cd to the directory and ls, or ls -al, no files are present This is probably something to do with permissions, right?   Terminal dump:      root@debian:/var/www/upload# ls -al     total 8     drwxr-xr-x 2 root root 4096 Sep 21 17:45 .     drwxr-xr-x 7 root root 4096 Sep 21 17:45 ..     root@debian:/var/www/upload# locate Octocat     /home/user/Desktop/Octocat-v1.stl     /var/www/upload/Octocat-v1.stl   Thanks in advance


Is there a point of beating Vault of Glass raid on Hard after finishing on Normal?

I beat the vault of glass on normal mode, but I got no items just ascendent energy/shards.  Now I'm wondering if I were to beat it on hard, would I get anything else? I know the chests that I've opened in normal model won't give me anything, but what about the rest of the raid?  I also noticed that after I beat  Vault of Glass on normal, it still says there are rewards, does that mean I can do it as many times as I'd like per week and still have a chance of getting raid gear?


Script called by .bashrc with "exit" prevents log-in

I caught myself out; I couldn't log into root after I made a script and called it from ~/.bashrc.  ~/.bashrc:  #... do stuff then run my script source ~/myscript.sh   ~/myscript.sh:  #!/bin/bash if [myConditional]; then   exit fi # otherwise do stuff   What I had hoped was that when I log in as root, myscript.sh would be run, and if myConditional was true, myscript.sh  would stop running any further commads, but would return to .bashrc and the user would still be logged in as root as usual. But instead, exit stopped me from being able to log in at all! It just returned me to a login prompt.  Is there another command I should be using besides exit? Obviously I could just extend the if statement by having an else statement and removing exit, but for educational purposes I'd like to know if there is a more appropriate approach. (Also partly because I want to avoid deeply nested if statements; it could be quite a large script)


$ \int_a^bx^nf(x)\mathrm{d}x=0,\ n=0,1,2,\cdots. $ Prove that $f=0$.

$f$ is a continuous function on $[a,b]$. If $$ \int_a^bx^nf(x)\mathrm{d}x=0,\ n=0,1,2,\cdots. $$ Prove that $f(x)=0$. A further problem is we only have $$ \int_a^bx^nf(x)\mathrm{d}x=0,\ n=1,2,\cdots. $$ Prove the same result.  I tried to use a polynomial to approach $f(x)$, i.e. $$ \forall \epsilon>0, \exists  P(x), \forall x\in[a,b],\ |f(x)-P(x)|\leq\epsilon. $$ Therefore, $$ \int_a^bx^n(P(x)-\epsilon)\mathrm{d}x\leq\int_a^bx^nf(x)\mathrm{d}x\leq \int_a^bx^n(P(x)+\epsilon)\mathrm{d}x. $$ But I do not know how to go on. It seems we only need to see the coefficient of the first term, but I cannot write a clear proof of that. Appreciate any help!


C++ constructor initialization when using template classes

I am writing a template class Foo as follows  Foo.h  template <class T> class Foo{ public:     Foo(int m, int n, T x); private:     int _m;     int _n;     T _x };   Foo.cpp  template <class T> Foo<T>::Foo(int m, int n, T x):_m(m), _n(n), _x(x){}   Now, when I try to initialize the class, I get a compilation errors  int main() {     Foo<int> a (2,3, 4); }   Errors:  Invalid arguments '  undefined reference to `Foo::~Foo()'  undefined reference to `Foo::Foo(int, int, int)'  Is there any mistakes in the .h or the .cpp files? or should I initialize the class in a different way?


Is there a function such that f(x)= the decimal part of x ( sister function of integer part function).

I'm looking for a little formula that would allow me to convert the degree mesure of an angle into its radian mesure.   In case the degree mesure is greater than 360° the complete 360° turns contained in the angle do not count.   So the idea is as follows: (1) first dividing the degree mesure by 360, and keeping only the decimal part of the quotient.   Then, (2) multiplying the decimal part by 360 and (3) multiplying the result by pi/180 in order to get the redian mesure.   Is there a known function that allows me to keep only the decimal part of a number?   I mean, sure this function exists, but does it have a name? Is it possible to find it on some calculators?


Order of group element divides order of finite group

Proving this can be done as follows: consider a finite group G and elements $g_i \in G$ for some integer $i$. Now consider $\langle g_i \rangle = \{g_i^n: n\geq 0\}$, a generator. It can be proved that $\langle g_i \rangle \leq G$ and that the order of $g_i$ is equal to the order of $\langle g_i \rangle$, so $|\langle g_i \rangle| \leq |G|$.  We can now use Lagrange's theorem which states that if $H \leq G$ then $|H|$ divides $|G|$ and we're done. But...  Is there a simpler way to prove this fact?


problem with arrays in python with the same function

So I'm having A VERY STRANGE scenario, I've simplified the code, but having the  SAME issues.  def write_to_bf_of_lpr(bf_source, bf_destination, lpr_index, start, length):     for x in range(length):         bf_destination[lpr_index][start + x] = bf_source[start + x]  source = ['a','b','c','d','e']  destination = [[0]*5]*3 dets2=[[0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]  for x in range(1):     write_to_bf_of_lpr(bf_source=source,bf_destination=dets2,lpr_index=x,start=1,length=2)  for x in range(1):     write_to_bf_of_lpr(bf_source=source,bf_destination=destination,lpr_index=x,start=1,length=2)   this code is quite simple to understand, what I wish to do is only change specific  array each time (or iteration).  Now: when I write in shorented version: destination = [[0]*5]*3 it is changing ALL the arrays within SINGLE iteration.  When I write in the LONG version (which is not preferable ) I get the CORRECT version.  You can see that dest2 is the correct, while destination is the wrong answer.   The funny thing is, that I simply COPIED the values from the short version... and there's different result...  Is it Pycharm bug, python, or am i missing something? please see screenshot of the output


Redirecting from http to https in Apache

This is a  about redirecting from http to https in Apache Related:     I have an Appache web server which serves both http://example.com/ and https://example.com/. I want to redirect all http requests to https. Currently I'm using this .htaccess rule to redirect http requests to https. RewriteEngine On RewriteBase / RewriteCond %{HTTPS} off RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}   It's working as expected for example.com but the same rule is not working for sub links, when I access existing links, like example.com/about it will still load in http, no redirection happens for existing links. How can I make Apache redirect all http requests to https?


Subject-verb agreement question after WHAT

I have a question about how the verb LOOK below should be conjugated:  1.There are neatly-dug beds filled with what look like carrots, chard and kale...    There are neatly-dug beds filled with what looks like carrots, chard and kale...    Should LOOK agree with WHAT or with the vegetables?  Thank you.


How do i fix "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException"?

Hello I have a little game I made for practice. I am able to put a JLabel on the screen but, when I run the ActionListener actionPerformed third if statement it stops the game. Also i have no idea what to change for the "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException" Error. Thanks :) Here's the code:  package me.mikail.movement;  import java.awt.BorderLayout; import java.awt.Color; import java.awt.Graphics; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener;  import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.Timer;  public class Player extends JComponent implements ActionListener, KeyListener{  Timer time = new Timer(10, this); private int x = 0, xSpeed = 3, y = 0, ySpeed = 4, stickX = 0, stickY = 400; private JFrame frame; private int oneup = 0; private JLabel info;  public static void main(String[] args){     Player p = new Player();     JFrame frame = new JFrame("Player Practice");     JLabel info = new JLabel(" ");     frame.setSize(500,500);     frame.setVisible(true);     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     frame.add(p);     frame.getContentPane().setBackground(Color.BLACK);     frame.setResizable(false);     frame.addKeyListener(p);     info.setOpaque(true);     info.setBackground(Color.WHITE);     frame.add(info, BorderLayout.SOUTH); }  public void paintComponent(Graphics g){     super.paintComponents(g);     //Ball     g.setColor(Color.BLUE);     g.fillRect(x, y, 30, 30);     //Stick     g.setColor(Color.RED);     g.fillRect(stickX, stickY, 75, 10);     time.start(); } public void points(){     int counter[] = {0,1,2,3,4,5,6,7,8,9,10};     for(int i = 0; i<=oneup; i++){         info.setText("You have "+counter[i]+" point(s)");     }     frame.add(info, BorderLayout.SOUTH); } public void actionPerformed(ActionEvent e) {     //Y's 0 is on the top     //X's 0  is on the left     if(x<0){         xSpeed = -(xSpeed);     }     if(x>=470){         xSpeed = -(xSpeed);     }     //when block hits stick     if(y==stickY){         if(x>=(stickX)&&x<=(stickX+75)){             ySpeed = -(ySpeed);             oneup = (1+oneup);             points();         }else{         }     }     if(y<0){         ySpeed = -(ySpeed);     }     if(y>=450){         ySpeed = -(ySpeed);     }     x = (x + xSpeed);     y = (y + ySpeed);     repaint();  }  public void keyPressed(KeyEvent e) {     int key = e.getKeyCode();     if(key == KeyEvent.VK_A|| key == KeyEvent.VK_LEFT){         stickX = (stickX - 50);     }else if(key == KeyEvent.VK_D|| key ==  KeyEvent.VK_RIGHT){         stickX = (stickX + 50);     }else{         System.out.println("Why did you type that?");     } }  public void keyReleased(KeyEvent e) { }  public void keyTyped(KeyEvent e) { } }


Fallback jQuery Reference when Google APIs inaccessible

Stack Exchange relies on jQuery to provide some essential functionalities, such as Log In.  Currently, the reference is to Google APIs.  <script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>   Although the availability of Google APIs is high, the accessibility may vary between different areas in the world.  I suggest add a secondary reference, such as , when Google APIs is not accessible.  The issue turns out to be more severe. If I want to log in to Stack Exchange, I have to go to my office.


Boot repair did not work to boot Windows

I installed Ubuntu 18.04 LTS alongside Windows 8.1.   I tested the different configuration of boot repair software, but Windows did not boot at all and I can only access Ubuntu.     fdisk outputs this:    efibootmgr gives me this information:


(Re?)Install Ubuntu on a Dell laptop that had Ubuntu preinstalled

I have Dell Laptop that is 15 5567 7th Generation. So it was maybe pre-installed as Dell says and I can see in the product information that this laptop is Ubuntu built in and based not Windows.  So I want to get my Ubuntu OS again. How can I do that?


Is there any way to load a postgresql style for a vector layer using python? There is a function: loadNamedStyleFromDb (const QString &db, const QString &theURI, QString &qml).Does it support loading of postgresql styles?


Wordpress Export Import Site Navigation Menu

When I do an export and import the menus get transferred but I have to set the Site Navigation Menu manualy. Obviously it's only a small detail but can I ask is this a bug or expected behaviour and is there any way to include the site navigation menu selection in the export file.   The same thing is the case for custom menu widgets.


How can I allow all players to use the teleport command without the use of mods or op permissions?

I have just created a Minecraft 1.13.1 server and was wondering if there was any way to give everyone the teleport command even if they are not op. If not, is there a way that I could make them op but only have access to the teleport command?


Creating a 'sub-screen', similar to how watch behaves

I have a Python script which generates a lot of different text outputs that require me to clear the screen quite regularly. The problem with this is that once the script is finished, I have a terminal full of junk that I no longer need. I could just clear the terminal, but I'd prefer to have a behaviour similar to what happens when you 'watch' a command.  Watch makes it's own kind of 'sub-screen', and once you kill it you're returned to the terminal with all the displayed output from your command cleared away and your previous commands shown in the terminal. I think this is much cleaner.  Is there any way to achieve this? I'm using C shell if it's relevant but I could just as easily use bash or some other shell.


Getting generic error message when attempting to post Q in SO

I'm trying to post a question on SO, and am seeing the following when I click the "Post Your Question" button:    However, there is no other info anywhere on the page as to what the error might be. Tried it twice, and still getting the same error. Bug, or PEBKAC error? If PEBKAC, how do I figure out what's preventing me from posting so I can fix it?


Using Google Earth Engine to filter Landsat Daytime image?

How do I filter Landsat imageCollection by their time of collection?  For example, if they are daytime or nighttime, which might be specified as Ascending or Descending.   I don't know which metadata keyword to use for filtering out by that.


How to install Google Services on a Garmin Fleet 790 Navigation Tablet?

I tried different approaches.   Installing the APKs: Login, Framework, Service and last but not at least Playstore wont work. (I tried it successfully on fire tablet)  In factory mode the menu Point: install from Sd Card wont be Displayed. To install Gapps from there.  Is there any other method to make Google Play Services run on the device?   the navigation tablet is  based on Android 6.0.1  i tried to follow the describtion from @izzy, but if I use the adb sideload i get:      "adb : sideload connection: closed .. trying pre kitkat sideload   method..'   and than the connection fails again and is closed too.   starting the device in factory mode and try to install it says:      "failed to open driver control no such file"   underwards it says that i could use adb sideload, but when i try my computer says      "no connected device"


General way of finding the commutator subgroup of A4.

The title essentially says it all.  Is there a way of efficiently finding the commutator subgroup of $A_4,$ and groups in general?  I know that the commutator subgroup must be normal in $A_4.$  I know the conjugacy classes are classes of cycle type:  $1$  $2, 2$  $3, 1$  The normal subgroups must be a union of the conjugacy classes. Does this mean that the commutator is:  e+conjugacy class of cycle type $(2, 2)$+ conjugacy class of cycle type $(3, 1),$  where e is the identity element of $A_4$?  Please make the explination as simple as possible, I'm having difficulties with abstract algebra.


Flag ban banner showing false ban lift day

Not that I am complaining about being allowed to flag posts, but I got really scared when I saw this banner in my flag history after I had randomly tried to flag a post and succeeded and assumed that it is .


How to get the last value of an ArrayList

How can I get the last value of an ArrayList?  I don't know the last index of the ArrayList.


How can I extract/change lines in a text file whose data are separated into fields?

How can I manipulate field-based data from the commandline? For example   How can I print only lines whose Nth field is foo? How can I print only lines whose Nth field isn't foo? How can I print only lines whose Nth field matches foo? How can I change field N to foo?   Is there a standard approach or toolset that facilitates manipulating field-based data on *nix systems?


Sum of radicals is rational only for perfect squares

How can we prove that if $a_1\sqrt{n_1}+a_2\sqrt{n_2}+\dots+a_k\sqrt{n_k}\in\mathbb{Q}$ with $a_1,a_2\dots, a_k\in\mathbb{Q}^{*}_{+}$, then the natural numbers $n_1,n_2,\dots, n_k$ are perfect squares?  I have proved it for $k=1,2,3$ but for $k\geq 4$ I don't find anything. I couldn't show even that $\sqrt{2}+\sqrt{3}+\sqrt{5}+\sqrt{7}\notin\mathbb{Q}$.


Seems to obviously be a scam.. need advice on possible outcome

I applied for a job entitled 'Freelance Market Research', within 2 hours I recieved an e-mail informing me that I had the job. Already set alarm bells ringing so I said I would be delighted to possibly join the team but could I have more information.  I was then informed that my first task would be receiving a cheque in the post and I was to deduct £640 as my 'wages' and the rest was to be used at a MoneyGram outlet.. to 'review' their service.  Now I know this is shady as hell and I replied saying I was no longer interested, but I feel a little anxious that this company now has my address and phone number.. if this cheque was to still be mailed to me could I just ignore it and destroy it and nothing more could come of it?  I'm guessing that as long as I dont go through with the task or attempting to cash the cheque I'm not doing anything that could get me into bother with the Law right?  Thanks in advance for any advice and sorry it's so long. <3


What kind of math do I need got general relativity?

I'm 15 this year and have a passion in physics What kind of math do I need to tackle general relativity?  Also what year in uni do we learn about general relativity?


$E\left[ \max(X_1,\cdots,X_n) \right]$ with i.i.d. $X_i\sim Exp(\lambda) $

Question. Let $ X_1,\cdots,X_n $ be i.i.d. random variables with exponential distributions, $ X_i\sim Exp(\lambda) $. Find $E\left[  \max(X_1,\cdots,X_n) \right]$. My approach. Let's find a recursive relation in terms of $ n $. Define \begin{align*} &Y_1 = X_1,\\  &Y_2 = \max(X_1,X_2),\\ &\vdots\\ &Y_n = \max(X_1,\cdots,X_n).  \end{align*} We have the relation \begin{align*}   &Y_n = \begin{cases}   X_n\ &{\rm if}\ X_n>Y_{n-1},\\   Y_{n-1}\ &{\rm otherwise},   \end{cases}\implies Y_n = Y_{n-1} + (X_n-Y_{n-1})1_{\{X_n>Y_{n-1}\}}\\   &\implies E[Y_n] = E[Y_{n-1}] + E[(X_n-Y_{n-1})1_{\{X_n>Y_{n-1}\}}].  \end{align*} Now, using the independence of $ X_n $ and $ Y_{n-1} $, we have \begin{align*} E[(X_n-Y_{n-1})1_{\{X_n>Y_{n-1}\}}]& = \int_{0}^{\infty}\int_{0}^{\infty}(x-y)1_{\{x>y\}}f_{X_{n}}(x)f_{Y_{n-1}}(y)\ dx dy\\ & = \int_{0}^{\infty}\int_{y}^{\infty}(x-y)f_{X_{n}}(x) dx\ f_{Y_{n-1}}(y) dy\\ & = \int_{0}^{\infty}\dfrac{\exp(-\lambda y)}{\lambda} f_{Y_{n-1}}(y) dy  \end{align*} So, \begin{align*}   E[Y_n] = E[Y_{n-1}] + \int_{0}^{\infty}\frac{\exp(-\lambda y)}{\lambda} f_{Y_{n-1}}(y) dy.  \end{align*} But I do not know what to do with the inetgral.


BGE: Cube parented to another cube not colliding with objects

I have a cube (cube.1) parented to another cube (cube.2), and both cubes are dynamic bodies with the same properties. Both cubes have "box" collision bounds. Also, both cubes are inside a room.    When I move cube.2 while in the game engine, it collides with the walls of the room and stops.    But cube.1, which is parented to it, does not. Why is this happening? Also, what can I do to make cube.1 collide with objects and stop moving (stop going beyond their faces)?


Dependencies still exist in "dpkg -l" after running "apt-get remove dependencies-names"

I suspected that installing xfce4 cause some issues in Ubuntu so I removed them using apt-get remove xfce4 xfce4-goodeis.  But when I ran 'dpkg -l' I still can see some libraries and packages for xfce4:  $ dpkg -l | grep -i xfce rc  libexo-1-0:amd64                              0.10.2-2                                 amd64        Library with extensions for Xfce rc  libgarcon-1-0                                 0.2.1-1                                  amd64        freedesktop.org compliant menu implementation for Xfce rc  libxfce4ui-1-0                                4.11.0-0ubuntu1~ppa0.13.10.1             amd64        widget library for Xfce - Gtk+2 variant rc  libxfce4ui-common                             4.11.0-0ubuntu1~ppa0.13.10.1             all          common files for libxfce4ui rc  libxfce4util6                                 4.10.1-1                                 amd64        Utility functions library for Xfce4 rc  libxfcegui4-4                                 4.10.0-2                                 amd64        Basic GUI C functions for Xfce4 rc  libxfconf-0-2                                 4.10.0-2                                 amd64        Client library for Xfce4 configure interface rc  mousepad                                      0.3.0-2                                  amd64        simple Xfce oriented text editor rc  thunar                                        1.6.3-1ubuntu1                           amd64        File Manager for Xfce rc  xfce4-appfinder                               4.10.1-1                                 amd64        Application finder for the Xfce4 Desktop Environment rc  xfce4-clipman                                 2:1.2.3-2ubuntu1                         amd64        clipboard history utility rc  xfce4-mixer                                   1:4.10.0-1ubuntu2                        amd64        Xfce mixer application rc  xfce4-notes                                   1.7.7-3ubuntu2                           amd64        Notes application for the Xfce4 desktop rc  xfce4-panel                                   4.10.1-1ubuntu1                          amd64        panel for Xfce4 desktop environment rc  xfce4-power-manager                           1.2.0-2ubuntu1                           amd64        power manager for Xfce desktop rc  xfce4-session                                 4.10.1-1ubuntu1                          amd64        Xfce4 Session Manager rc  xfce4-settings                                4.11.1-0ubuntu1~ppa0.13.10.1             amd64        graphical application for managing Xfce settings rc  xfce4-terminal                                0.6.2-3ubuntu1.1                         amd64        Xfce terminal emulator rc  xfce4-volumed                                 0.2.0-0ubuntu1                           amd64        volume keys daemon rc  xfdesktop4                                    4.11.2-0ubuntu1~ppa0.13.10.1             amd64        xfce desktop background, icons and root menu manager rc  xfwm4                                         4.11.1-0ubuntu1~ppa0.13.10.1             amd64        window manager of the Xfce project   I copy-pasted all these packages\libraries to form an apt-get remove command to remove all of these dependencies, and the command ran normally, but running dpkg -l | grep -i xfce showed these dependencies again !  Why are these dependencies still installed ?


Copy tables from spreadsheet software directly as new table format

When I copy the specific Excel cells and paste them on a Stack Exchange site, it's automatically pasting as an image. It would be great if it is pasted as the . OS   : Windows 10 Excel: Office 365 Version 1908 For example, after pressing Ctrl+V or ⌘+V, the following image is added:  Instead, the following native HTML table should be generated:     S/No Item Qty     1 Product 1 10   2 Product 2 15   3 Product 3 30


Can you trade Pokemon from 7th gen (Sun/Moon) to 6th gen (XY, ORAS) and back?

Title says it all, I don't see confirmation in  and a cursory google search seemed to say assume no and speculate about the pokemon bank.


Texture appears to stand still when the camera is animated

I’m modeling an address book and have a mesh with tabs (UV mapped). I’ve created one .png with a paper surface image and the letters of the alphabet in black. Animated a slow camera pan. After rendering a targa sequence the texture appears in place but there seems to be another texture or layer or grain that doesn't move. Its mostly noticeable around the black fonts but once you see whats going on its everywhere. Almost as if there is a slight transparency.  Blender 2.76 / Cycles  Link to project file and short .mov   Thanks!


Gimp: toolbox display & main window resize issues in 12.10

I recently installed 12.10. When Gimp is launched, its main window extends below the bottom of the screen, and cannot be resized vertically, only horizontally. Also, the toolbox window isn't displayed correctly; it doesn't have a title, nor is it framed. Instead, all the toolbox icons appear in a single column that extends below the bottom of the screen. The problem persists after reinstalling Gimp.  In case it's relevant, I'm having two other graphics-related issues: text in Firefox frequently gets garbled, and the whole system periodically freezes, either for a few seconds or without returning to normal. I'm running Intel integrated graphics (controller i915).


whiat is different between function conj(x) and method x.conj() python

I know conj(x) and x.conj() do the same thing, but what is the main difference?. Is that we can do any function as method such as sum(x) written as x.sum()?


Does 64 Bit AMD Works on intell core 2 duo?


Dropping Internet connection on Realtek Semiconductor Co., Ltd. RTL8821AE

I have continuous problems of network dropping connections on wifi with ubuntu 16.04, I have an ASUS R510J, this is my network card:  ##### lspci #############################  03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]         Subsystem: AzureWave RTL8821AE 802.11ac PCIe Wireless Network Adapter [1a3b:2161]         Kernel driver in use: rtl8821ae  04:00.1 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 12)         Subsystem: ASUSTeK Computer Inc. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [1043:200f]         Kernel driver in use: r8169   sudo service network-manager restart doesnt's help, as I never regain internet connection after it drops, and I have to restart the PC. On Ethernet cable I have no problem.  What do you think is the issue? drivers?  thank you


Illustrator CS5 brick pattern with perspective

I created a curving arrow shape that starts wide at the bottom and thins out near the top where the point is. I also created a brick pattern swatch but when I apply it to the shape it appears like the pattern is overlaid instead of like a real road where the bricks follow the shape and narrows near the most distant point. How can I apply a perspective to the brick pattern without looking like I used a clipping mask?  Here is a link to what I achieved with a clipping mask - not what I want though. I need the bricks to look like they are inlaid just like in real life.


Hey if i want sculpt something, there is one problem that i can't sculpt the left,right,front and back but top and bottom is going normal. Can someone help?


UV, Modify UV island when modifying mesh

I saw somewhere that there was an option in Blender that allows you to modify the UV map at the same time you modify the topology of the object. I remember seeing a video where a box working as a wall had some faces extended to make the wall larger. In that video, the UV islands for those walls extended at the same time so the texture proportion wasn't affected. I can't find how to do it? Apologies if I have just dreamed it but I remember clearly and it is really frustrating I cant find how to do it after googling for a while.


I use a '/services/data/v41.0/tooling/sobjects/RecordType/'. But picklistValues is always empty, I need it to edit from code


How to make chrome to force reload JS from my web server?

I have a PHP website with lot of JS and CSS files included with the  tag. The problem is whenever I update any JS or CSS and then open my website, chrome is still loading old versions of the JS,CSS . I know client side we can force refresh by Ctrl+Shift+R , but it's too tough to instruct my website users to do this every single time.   I have tried these but still no luck. So please suggest a way to force the browser to reload JS from my server every time instead of cache.    <meta http-equiv="cache-control" content="no-cache"> <!-- tells browser not to cache --> <meta http-equiv="expires" content="0"> <!-- says that the cache expires 'now' --> <meta http-equiv="pragma" content="no-cache"> <!-- says not to use cached stuff, if there is any -->


I am having trouble with my email validation code using function validateEmail (str). Any suggestions?  //validates email address form function validateEmail (str)     {     var retVal;     var atpos=retVal.indexOf("@");     var dotpos=retVal.lastIndexOf(".");     if (atpos<1 || dotpos<atpost+2 || dotpos+2>=retVal.length)     {     retVal = false;              return retVal;     }


What are the differences between UTF-8, UTF-16, and UTF-32?  I understand that they will all store Unicode, and that each uses a different number of bytes to represent a character. Is there an advantage to choosing one over the other?


I have a code from ex colleague. he declared some sort of macro like this :  #define work_dir "/usr/io/track" #define macro_test(a1,a2,a3,a4)\ {\     .name=a1,\     .family=a2,\     .idnum=a3,\     .badlog=a4,\     }   and later on he called this macro like:  macro_test(test "John","macdonald",14,"no");   I know this might not enough detail, however I am just wondering about declaring this sort of macro. it seems to initialize structure but it is not. much appreciated if you can help me.


I'm having trouble with Google homepage, search results, Google Images. They are being showed in a very unusual way. What's the reason behind this?

All the things mentioned above are working fine in Firefox but I'm having problem in Google Chrome. I'm posting below the screenshots of both the browsers displaying the same pages differently.   Firefox :  As I said, everything is normal in Firefox.   Google Chrome :  All the images are being displayed in a weird way. When I click on an image it redirects me to the page hosting the image, instead of zooming it. Also this error is displaying in the console.     All other sites are working just fine on Chrome. Google homepage, images and search results are the places I've encountered problems on.


I'm ranked as one of top 4% users of Data Science Stackexchange. I'm applying for a PhD program in related field.   Shall I mention my Stackexchange rank in my resume? If yes under what title?


techpalle;  public class MyProgram {      public static void main(String[] args) {          System.out.println("Tri" + "angle" =="Triangle");       }  }   Tri is stored in string constant pool, angle is also stored in string constant pool and after concatenation is done Triangle will be stored in heap memory.  Right Hand Side Triangle will be stored in string constant pool == compares the address How am I getting true then?


Copy data through SSH tunnel over multiple hops

We have two main environments in question:  Development and QA  Each environment has two servers:   Jump Box Application server   In order to connect to the application server, you must connect to the jump box first, and then SSH to the Application server.  There are a few rules in place courtesy of the firewall:   You MUST connect to the application server via the jump box The application server cannot connect to either jump boxes The jump boxes are on the same subnet, and CAN talk to each other.   Our Problem  We have a lot of content (670 GB) on the DEVELOPMENT APPLICATION SERVER, and we need to get this to the QA APPLICATION SERVER.  Copying this data to the jump boxes is not an option because they lack the required amount of space.  I did some research, and learned that we could potentially do a series of tunnels through these servers so that we can stream the data straight from one app server to the other via the tunnels. However, the problem that we cannot connect to the jump box from the application server.  Do we have any options? This is getting to be a desperate situation, and time is of the essence. We do not have time to download the data and re-upload it. Copying across the network on the servers will go quickly, as it is a gigabit connection.


'm looking for a way to change my public IP address. You know that the one that other websites see.  I know what I'm looking for is basically a proxy server, but I don't want to use a proxy for 2 reasons:  1) It slows me down. 2) See reason   I'm using Ubuntu 9. I'm connecting to a public WiFi network (the ISP is Time Warner Cable). I'm getting my IP throug P.


What is the resolution of tapping a blocking creature?

Let's say I have declared a blocker during the correct phase and during the activate abilities step I choose to tap the blocker to use its ability.  All the abilities resolve and now we move to the declare damage step.  I believe the resolution is that the attacking creature remains blocked and that it deals damage to my blocker; however, the blocker does not deal damage to the attacker.  How would this change if the blocker had first strike? How would this change if the blocker was sacrificed?


What is the use of static variables inside C functions?

what is the use of static variable in this program   /* program to find the addition of n numbers without using recursion:*/ #include<stdio.h>  int main(){      int n,sum;      printf("Enter the value of n: ");     scanf("%d",&n);      sum = getSum(n);      printf("Sum of n numbers: %d",sum);      return 0; }  int getSum(n){      static int sum=0;      if(n>0){          sum = sum + n;          getSum(n-1);     }      return sum; }


java.lang.NullPointerException at java.util.Objects.requireNonNull ( Firebase based App is crashing due to this Error )

This is my first question on Stackoverflow. Somehow to complete my final year project I refer to Youtube videos.   My problem is:  I want to retrieve profile image from Firebase Database and wanted to  display image on the navigation header (i.e to display navigation header    profile image) and also to display that profile image on my setup activity that I have created.   But after running the app, it keep crashing. Here is the error:  java.lang.NullPointerException at    java.util.Objects.requireNonNull Error.   Logs  2019-01-24 17:55:18.199 6533-6533/academy.learnprogramming.subjoin I/Choreographer: Skipped 11 frames!  The application may be doing too much work on its main thread. 2019-01-24 17:55:18.233 6533-6533/academy.learnprogramming.subjoin I/AssistStructure: Flattened final assist data: 2600 bytes, containing 1 windows, 8 views 2019-01-24 17:55:19.620 6533-6533/academy.learnprogramming.subjoin D/AndroidRuntime: Shutting down VM 2019-01-24 17:55:19.621 6533-6533/academy.learnprogramming.subjoin E/AndroidRuntime: FATAL EXCEPTION: main     Process: academy.learnprogramming.subjoin, PID: 6533     **java.lang.NullPointerException         at java.util.Objects.requireNonNull(Objects.java:203)         at academy.learnprogramming.subjoin.MainActivity$1.onDataChange(MainActivity.java:92)**         at com.google.android.gms.internal.firebase_database.zzfc.zza(Unknown Source:13)         at com.google.android.gms.internal.firebase_database.zzgx.zzdr(Unknown Source:2)         at com.google.android.gms.internal.firebase_database.zzhd.run(Unknown Source:71)         at android.os.Handler.handleCallback(Handler.java:790)         at android.os.Handler.dispatchMessage(Handler.java:99)         at android.os.Looper.loop(Looper.java:187)         at android.app.ActivityThread.main(ActivityThread.java:7025)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:514)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:888) 2019-01-24 17:55:19.636 6533-6533/academy.learnprogramming.subjoin I/Process: Sending signal. PID: 6533 SIG: 9   Block Of Error : MainActivity.java:92  UsersRef.child(currentUserID).addValueEventListener(new ValueEventListener()  {             @Override         public void onDataChange(@NonNull DataSnapshot dataSnapshot)  {             if (dataSnapshot.exists())             {                  String fullname = Objects.requireNonNull(dataSnapshot.child("fullname").getValue(String.class));                 String image = Objects.requireNonNull(dataSnapshot.child("profileimage").getValue(String.class));                  NavProfileUserName.setText(fullname);                 Picasso.get().load(image).placeholder(R.drawable.profile).into(NavProfileImage);              }          }          @Override         public void onCancelled(@NonNull DatabaseError databaseError)         {          }     });


Prove that lim sin (1/x) as x-> 0 does not exist.   Not really sure where to go with this, do I approach from both the right and left?


Can I bring a pack of razor blades on a plane?

I have to take a flight soon and I want to know if I can take a pack of razors with me. They are in a pack that is designed to not let any out unlesss a person really wants to open it. I'm going to the USA so, can I?  I mean plain old razor blades:


From origination point of view, if i understand correctly, we 'derived' imaginary number mathematically e.g. x^2 = -1. But what is the use of such number in study of mathematics? Are they really helpful in solving some problems or understanding some other problems or its just some useless observation by some mathematician?  Disclaimer: I'm not mathematician. I didnt get answers in


Does dark matter / dark energy could be simply regular mattter

First of all I'm not a physist, my formation is related to Information Systems but I was always curious regarding the laws that rules our universe.   I would like to apologize as well for my bad english since it is not my mother language.  Recently I watched a video from professor Michio Kaku which makes me curious about the lack of information related to dark energy / dark matter.  To start with I would like to think that before the big bang, nothing else existed, even the empty space, so everything was concentrated in a single high density ball of pure energy with a mass tending to be infinite.  When the big bang took place, this ball of energy expanded in all directions, expanding the own space and everything inside trough all directions. Today we know that nothing can go faster than speed of light, however this afirmation is based on the fact that the light is travelling on vacuum or empty space.   Considering a supposition that our own dimension was created together with the big bang including the space, this law may not be applied at the very first moments after the big bang since the objects could be travelling ahead of the speace itself.  If we consider that during the big bang, 80% of the energy released started travelling faster than light in all directions, creating the own space on it's way, and then we had the remaining matter travelling below the speed of light behind it.  Since nothing on space can travel faster than speed on light, we can not see the objects that initially started travelling faster than speed of light, however their gravitional effects can be feel at the the galaxies near the boundaries of the universe which are being pulled away from each otther.  The big questions about dark energy and dark matter is that something should exist otherwise galaxies won't have enough mass to be formed as well as the fact that the speed the universe is expanding is increasing over time. If instead of having dark energy acting on the space between the matter, we have simply a massive amount of matter outside the know boundaries of our universe pulling the galaxies away from the centre of the universe, could this be a plausible solution for the dark matter / dark energy question?  Again sorry for the stupid question, but it was something that came into my mind and even after looking for answers on internet I could find anything related to it.


What is the most safe approach? This one: $id = mysqli_real_escape_string($link, $_POST['id']); echo $id;  Or this one: $unsafe_id = $_GET['id']; $safe_id = (int)$unsafe_id; echo safe_id;


Where does this famous rhythm pattern come from (oftenly used to knock on a door)?

This rhythm pattern seems very famous and is oftenly used to knock on someone's door, sometimes as a code:    Does it have an history? Where does it come from?


Why do human women have periods when most animals don't? It is known that the unfertilized egg needs to be shed from the uterus. But why shed the whole endometrium? Why didn't evolution put macrophages to work to simply digest the ovum and only the ovum, instead of the physiologically, energy-draining process of menstruation and accompanying blood loss? Also, are there any other purposes for menstruation, besides wiping out dead ova?      Sites I used for references:  1.  -                       Menstruation seems energy draining, in my perspective, given that 30-40 ml of blood is lost × 3-4 days × 12 months × 15 years on average - that is a lot of blood loss.  2. Also see this .    Related question: .   My question is different from this related question because there the OP is concerned about the survival advantage of the menstruation with respect to the predators. Here I've asked why menstruation and why not phagocytosis as the former to me seems to be highly energy consuming process. Also as the fellow post writer had earlier suggested though the two questions  seem to be one and the same, they are subtly different and aimed for two different audiences as I emphasise more on the physiological aspects of menstruation and the related question's OP needs clarification about survival advantage and other ecological aspects of menstruation.


How can I make text just an outline and not filled?

I've got a text mesh but i'm trying to make it so that it's not filled but instead is just an outline of text is there anyway to do this? This is the effect i'm trying to achieve:


How do I check whether a file exists without exceptions?

How do I check whether a file exists or not, without using the  statement?


BufferedReader from InputStreamReader(System.in) don't take STDIN stream

trying to pass line info (2 lines reprensting a user and a password) to a java application, the log show that it take the lines but empty value (like only tkae the \n  code is decompiled (only have the copiled version) showing this function and call  public String getUser(String prompt)   {     System.out.print(prompt);      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));     String userName = null;      try     {       return br.readLine();     }     catch (IOException ioe) {       System.out.println("IO error trying to read your name!"); }     return null;   }   call in main code is    try       {         String user = application.getUser("User: ");         User = user;         char[] pswd = application.getPassword(System.in, "Password: ");         if (application.isDebug()) {           application.log("verify User " + User);           }         ...       }   else {           application.log("ID not found!");         }   }   catch (Exception e) {     application.log("Exception during login, abort Batch now!");     System.exit(1);   }   calling with different redirection from the shell ex:   printf "%s\n%s\n" "MyUser" "MyPwd" | java SomeArguement  Compiledjar   show this in log  User: Password: [2019-09-25 14:06:26 CEST] getUserPlatformContext [2019-09-25 14:06:26 CEST] Exception during login, abort Batch now!  any idea why STDIN in not  "read" correctly by this code (this  confirm it should).  I also put lot more string to pass in case of previous code read STDIN before but it's the same  ----------- Other story ----------------------- finaly found the debug argument to pass and it show that the STDIN is correctly read for the  user prompt but hang on the getpassword that use  a buffer read from another type like ((PushbackInputStream)in).unread(c2) and failed at this level.


In the movie Indiana Jones and the Last Crusade (1989)  there is a scene with a dreathtrap:                                  The joke is, naturally, that in the classical latin alphabet there was no 'j' letter. Which brings the question why was there a 'j' letter on the plate at all? Or perhaps it was a different one distorted by time, or a cracked plate?


Use induction to prove that $2^n \gt n^3$ for every integer $n \ge 10$.


How are statistics on scientific papers inferred?

Referring to this question: , a kind user explained us how to read the following statement from the :.      Increasing carbohydrate intake was associated with increasing stroke   risk (HR = 2.01, 95%CI = 1.04–3.86 highest vs. lowest quintile; p for   trend 0.025).      Multivariable Cox modeling estimated adjusted hazard ratios (HRs) of   stroke with 95% confidence intervals (95%CI).   In the answer I was told to interpret this as:     The confidence interval suggests that we can conclude, with 95%   certainty, that the true hazard rate in the population could fall   anywhere between 1.04 and 3.86. In the broader population, the stroke   risk associated with increased carbohydrate consumption could be as   high as 3.86 times or as low as 1.04 times that of the comparison   group.   I don't understand what part of the original text gave this information on the confidence interval.


How to fix php use xxtea class XXTEA::encrypt($str, $key) get this ����>���||�

I use this link to encrypt words  but i get ����>���||�  how can i fix it like 'aabbsdsafdadfdd'      $logic = new Xxtea();     $str = $logic::encrypt('aaaaa','00852953005432100085295300543210');   i tryed to   $a = $logic::encrypt('aaaaa','00852953005432100085295300543210'); echo $logic::decrypt($a,'00852953005432100085295300543210'); // aaaaa   but $a is   ����>���||�  - -!


How many elements of have square roots in a field of 13 elements?

Initially, I thought since this field was isomorphic to $({0,...,12})$ , the elements $(0,4,9)$ would have square roots. However, when I checked the solutions, the answer was different. Thank you in advance.


"Dear Sir or Madam" versus "To whom it may concern"

When is it appropriate to use the terms Dear Sir or Madam and To whom it may concern?  The rules I was taught state that Dear Sir or Madam should be used when you're writing a letter to a person about something that person has direct involvement in (e.g. returning a defective product to a customer service department).  By the same rules, To whom it may concern would be used for situations in which the recipient is a third party to the topic of the letter (e.g. regarding a letter of reference or recommendation).  Was I taught correctly?  Is the rule actually something else?  Or is this one of those situations where many people have an opinion but there is no real rule?


"Failed to create user" due to regular expression error

I'm running Ubuntu 12.10 desktop 32 bit. Currently I have only a user, type administrator. I'd like to create another administrator user but I keep getting the following error:  Failed to create user GDBus.Error:org.freedesktop.Accounts.Error.Failed: running '/usr/sbin/adduser' failed: /usr/sbin/adduser returned an error (1): adduser: Please enter a username matching the regular expression configured via the NAME_REGEX[_SYSTEM] configuration variable.  Use the `--force-badname' option to relax this check or reconfigure NAME_REGEX.  Any suggestion is appreciated.


Recently I changed my partition scheme from MBR to GPT, and during after conversion I saw a another partition named EFI ... I don't have a good idea what does it do or its purpose ... but I think it's use for backup's.  So my question here is can you explain/tell me about EFI and it purpose?


Why is integration so much harder than differentiation?

If a function is a combination of other functions whose derivatives are known via composition, addition, etc., the derivative can be calculated using the chain rule and the like. But even the product of integrals can't be expressed in general in terms of the integral of the products, and forget about composition! Why is this?


I am looking for general instructions on remapping keys.  Can someone tell me how to remap F9 to PrtScr and F10 to ScrollLock button?  I have looked through every thread here and none of the suggestions worked.  I am using a Swedish keyboard setup and Ubuntu 12.04.


How to apply css attribute defined by js variable

I am trying to take the href attribute from an a tag, and apply that as the background-image of the anchor tag's child. For some reason it is not working. I have the following html:

   and the following javascript(using jquery):    $('figure').each( function() {     var thumb = $(this).find('.thumbnail');     var image = $(this).find('a').attr('href');     $(thumb).css('background-image', image);   });


Infinite Series: $\sum_{n=1}^\infty \frac{1}{2^nn}$

Just encountered a problem in my BC Calculus sequences and series unit that I just can't figure out.   I don't know the latex, but the problem was to find compute  $$ \sum_{n=1}^\infty \frac{1}{2^nn} $$ The handout was just on convergence, so it was easy to see that by ratio test, it does converge, but I think I'm missing some ideas to be able to calculate the sum.   We have done Taylor series, I just don't quite know how to go backwards, although my guess is that you find a way to write the partial sums and find it's value as the limit approaches infinity.  How would you go about solving this?  Thanks!


Macbook air mid-2012 w/ Mountain Lion.  Whenever I wakeup from a long sleep and also on some random moments when it's on, i get DNS resolution failures for every server, with nslookup saying ;; connection timed out; no servers could be reached; however, direct connections to IP addresses work correctly, since (among others) Skype works perfectly.  This resolves by itself after more or less 5 minutes, when DNS resolution gets back to work correctly, both with nslookup and in other applications (browser etc.).  I have Google's DNS servers (8.8.8.8 and 8.8.4.4) configured both on my network preferences and on my wireless router's settings.  Possibly related but still unsolved:   Any ideas?


What happens when a metallic dragon and a chromatic dragon mate?

Is it possible, and if so, what happens when a metallic and chromatic dragon mate? I'm most interested in blue and bronze dragons.  I'm interested in lore from all editions except the fourth edition.  This question is for a specific campaign of mine.  General information about dragon lore of breeding habits are also interesting, but in particular:    both what kind of offspring is producing what kind of lineage would follow for its own offspring?


What is the command to switch to normal user?

I am trying to "su/sudo" command to switch to a regular user. It asks me password and I enter admin password then it says su: Authentication failure. How can I switch to regular user, what is the problem?  walter@walter-VirtualBox:~/testdir$ su Password:  su: Authentication failure walter@walter-VirtualBox:~/testdir$


Existence of Topologically Transitive Maps on nice Metric Spaces

Let $(X,d)$ be a separable metric space with no isolated points.  Recall that a continuous function $T:(X,d)\rightarrow (X,d)$ is called topologically transitive if  Given $U,V$ non-empty open subsets of $(X,d)$ there is some positive integer $n$ such that $$ T^n(U)\cap V \neq \emptyset . $$  My questions are:  does there necessarily exist a topologically transitive function on $(X,d)$.  Is there a simple test (by simple I mean something easy to verify like Stone-Weirestrass for linear spaces) to verify if $T$ is topologically transitive of not?  Note:  If it makes it easier we can also assume that $X$ is a topological group.  (I know this helps when $X$ is the unit circle).


What does "divided highway" written on a white regulatory sign mean?

When it appears on a regulatory sign, what it means and what should I do, is the thing I have a great deal of difficulty with.   This is one of those signs I came across - Divided Highway.  What does it mean?  Many thanks in advance.


I am try to train a simple model following () to understand neural networks better but my model is unable to learn simple curves to segment the data. My loss keeps decreasing but not validation. Even if I make my model more complex its validation loss becomes constant very quickly(at 0.029) and the graph looks like    I dont understand why a multi layer can't learn the simple up curve after x=4? Would love some help and insights. Ideally this should work with one-two layers as the function it is learning is not very complex.  Here is my basic code:  NB_EPOCH = 300   def prepare_data(n_points=256):     x = np.linspace(0, 2*np.pi, n_points)     shift1 = 0.8     shift2 = -0.8      y1 = np.cos(x*1.2)+shift1     y2 = np.cos(x*1.2)+shift2      features1 = zip(x, y1)     features2 = zip(x, y2)      labels1 = np.zeros((n_points,))     labels2 = np.ones((n_points,))      return np.concatenate([features1, features2]), np.concatenate([labels1, labels2])   def create_model():      model = Sequential()     model.add(Dense(4, input_shape=(2,)))     model.add(Activation('tanh'))     model.add(Dense(4, input_shape=(2,)))     model.add(Activation('tanh'))     model.add(Dense(4, input_shape=(2,)))     model.add(Activation('tanh'))     model.add(Dense(4))     model.add(Activation('tanh'))     model.add(Dense(2))     model.add(Activation('softmax'))     model.compile(loss='categorical_crossentropy', optimizer='sgd',                   metrics=['accuracy'])      return model   if __name__ == "__main__":     features, labels = prepare_data()     f_len = features.shape[0]      labels = np_utils.to_categorical(labels, 2)     model = create_model()     print(model.summary())      model.fit(features, labels, nb_epoch=NB_EPOCH,batch_size=8,validation_split=0.2)      reshaped_features = features.reshape(features.shape[0], 2)        fig = plt.figure(1)       ax = Axes3D(fig) #fig.add_subplot(311, projection='3d')     ax.plot(features[:f_len/2,0], np.zeros(f_len/2), features[:f_len/2, 1])     ax.plot(features[f_len/2:,0], np.zeros(f_len/2), features[f_len/2:, 1])      # ###########################################     # Separation curve     # ###########################################     x,y = np.meshgrid(np.linspace(0, 3*np.pi, 50), np.linspace(-1, 1, 36))     input = []      for _x, _y in zip(x, y):         for i in range(len(_x)):             input.append((_x[i], _y[i]))      input = np.asarray(input)     classes = model.predict(input)      first_class_x = []     first_class_y = []     second_class_x = []     second_class_y = []      for i in range(len(classes)):         if classes[i][0] > 0.5:             first_class_x.append(input[i][0])             first_class_y.append(input[i][1])         else:             second_class_x.append(input[i][0])             second_class_y.append(input[i][1])      ax.scatter(first_class_x, np.zeros(len(first_class_x)),                first_class_y, c='r')      ax.scatter(second_class_x, np.zeros(len(second_class_x)),                second_class_y, c='y')      plt.show()


I just failed . This post looked good; very concise. However given that the question had 5 other answers, I thought the odds of this post being just a repeat of information in another answer was quite high.   I opened up the question, and the very first answer was the same as this one, word for word, and highly upvoted. Aha! I thought to myself, someone plagiarising for cheap rep. And I went to flag.  But as it turns out, the duplicate answers were one and the same, anonymised for the review.  I tried to have a think of ways to prevent this occurring, but I have to admit I'm drawing a bit of a blank. Does anyone else know of a way?   n.b.: I'm aware that a small amount of false positives as a price for catching more robo-reviewers is pretty reasonable, so if this isn't easily fixable I guess that's fine.


Prove that Cantor function is Hölder continuous

Let $C_k$ be the set obtained in the $k-$th stage of building the Cantor set, where  $$C_1=[0,\frac{1}{3}]\cup[\frac{1}{3},\frac{2}{3}]$$  $$C_2=[0,\frac{1}{9}]\cup[\frac{2}{9},\frac{1}{3}]\cup[\frac{2}{3},\frac{7}{9}]\cup[\frac{8}{9},1]$$  $$\dots$$  So we have   $$C_k=\bigcup_{j=1}^{2^k}I_{k,j}$$  where $I_{k,j}$ are pairwise disjoint closed intervals of length $3^{-k}$ in $[0,1]$, let  $$[0,1]\setminus C_k=\bigcup_{j=1}^{2^k-1}J_{k,j}$$  where $J_{k,j}$ are pairwise disjoint open intervals and each $J_{k,j}$ are located between intervals $I_{k,j},I_{k,j+1}$  define  $$F_k:[0,1]\to[0,1]$$  where  $$F_k(0)=0,F_k(1)=1,F_k(x)=\frac{j}{2^k}\quad x\in J_{k,j}$$  and $F_k$ is linear on each subinterval of $C_k$. We can show that $F_k$ converges to the Cantor function $F:[0,1]\to[0,1]$. Moreover, it can be shown that  $$|F_k(x)-F_k(y)|\leq\frac{3^k}{2^k}|x-y|$$  How can we show that $F$ is Hölder continuous of order $\log_32$ ?


Add desktop notifications for Chrome or Firefox

I noticed that chat supports desktop notifications to notify you when someone pings you, which made me think that maybe the main site has this functionality as well, and I'd really like to use it in that case. But I couldn't find an option to turn them on anywhere.  Chrome notifications look like this:


Computing the quotient $\mathbb{Q}_p[x]/(x^2 + 1)$

I am trying to compute the quotient $\mathbb{Q}_p[x]/(x^2 + 1)$ where $\mathbb{Q}_p$ represents the $p$-adic numbers. I already proved that if $p \equiv 2,3\mod4$, then $\mathbb{Q}_p[x]/(x^2 + 1) \cong \mathbb{Q}_p(i)$. Moreover, I also proved that if $x \equiv 1 \mod 4$, then $x^2 + 1$ has a root in $Q_p$ using Hensel's lemma. Online, I found that in this case $\mathbb{Q}_p[x]/(x^2 + 1) \cong \mathbb{Q}_p  \times \mathbb{Q}_p$. Why? A similar problem was posted here:. However, they do not address my question. Thanks in advance!


If $S=\{1,2,\dots,n\}$ and $P_n(k)$ be the number of permutations of $S$ having $k$ fixed points, then $\sum_{k=0}^nk.P_{n}(k)=n!$

Let $S = \{1,2,\dots,n\}$. Then $i \in S$ is said to be a fixed point of a permutation $p$ or $S$ if $p(i) = i$. Let $P_n(k) $ be the number of permutations of $S$ which have $k$ fixed point. Prove that $\sum_{k=0}^nk\cdot P_{n}(k) = n!$.


How might I describe washed up stuff in a word or phrase?  Asking for my granddaughter. She knows about "jetsam" but that's for things deliberately jettisoned:     unwanted material or goods that have been thrown overboard from a ship   and washed ashore, especially material that has been discarded to   lighten the vessel -    so does not fit in her story.  Neither does "flotsam", which is wreckage, though not deliberately discarded. And the "flot" says it's floating, not washed up.     the part of the wreckage of a ship and its cargo found floating on the   water. -


My homework assignment contains the following question:     Prove that $S^n = \{x \mid x \in \mathbb R^{n+1}, d(x,0)=1\}$ is connected.   Can you give me a hint please?  What I can do is nothing..


I used bezier curves and circles to make a shape, how do i transform it in to an editable object?

I used a bezier curve and a circle to make a claw shaped thingy around the bezier curve, I want to be able to edit the geometry of this shape, but don't know how to transform it in to an object.


What is the harm of an "overlapping" question? (usually closed as a duplicate)

I often see questions marked as duplicates because they "overlap" another question. Usually, the correct answer is a part of an accepted answer on another question.  Why wouldn't we want to allow the more specific question, to help people who might be looking for the same thing? Isn't that better than forcing them to hunt through long answers for the detail they need?  Here's the situation:   Question A asks about something complicated (like, "Who is Voldemort?"), and gets an answer that answers the question comprehensively, with lots of detail on related topics. Question B asks a more specific question about one aspect of the complicated topic (like, "Where was Voldemort born?"). Then, Question B gets closed a duplicate of Question A.   There's no doubt that the accepted answer for Question A includes the correct answer for Question B. But it's hidden inside a long answer, most of which is entirely unrelated to Question B.  Why wouldn't we want to encourage these more specific questions? Wouldn't it improve the overall quality of the site to have answers to all the "forms" a question might take?  Is there a cost to having overlapping questions that I'm not seeing?


I've found a horse in Skryim and I ride it a bit to explore the wild but when I dismount, it wanders away and doesn't stay where I leave it. How do I stop it from doing this? Is there a special thing I forgot about horses? I didn't steal this horse - it was from an Imperial Fort that I've cleared.


Hi i wanted to know if it is possible to remove the swap partition and merge it with home partition. I'm dual booting with mac os using refind, and tried to boot gpartedlive from refind, but it wont boot and gets stuck on a terminal-like black screen.   Edit : I forgot to ask how come I have two recovery hd partitions? is it safe to delete one? maybe it's because I did a fresh reinstall of the whole osx system?


How to Boot FAT Flash Drive with Ubuntu Installer

I have a 1.86 GB Flash Drive and it is a FAT File System. I have downloaded the Ubuntu ISO. I need to be able to boot the flash drive with the Ubuntu ISO and be able to install it to another computer by booting from the flash drive. How do I do this?


In a .tex document, I'm using the comment package to produce two different versions (let's say : versionA and versionB) of the document. Each version contains different parts (it could be paragraphs, equations,...). If I use \includecomment{versionA}, it will include all the content between \begin{versionA} and \end{versionA}. Now, let's say some of the parts in each version are marked with a *. How can I ask latex to compile only the * parts in one version ?   It may be clearer on the following example. Let's say I have  \documentclass[10pt,a4paper]{article}  \usepackage{comment} \includecomment{versionA} \excludecomment{versionB}  \begin{document}  \begin{versionA}  *part1  part2  *part3  \end{versionA}  \begin{versionB}  part1  *part2  \end{versionB}  \end{document}   I would like something which enables me to do : "compile all the content of versionA" or "compile only the content marked with * in versionA" (same for versionB). I hope this is clear!


Does $a^n \mid b^n$ imply $a\mid b$? I think it does but haven't been able to prove it.  I don't know much number theory so an elementary answer would be great.


Errors occurred during the build.Errors running builder 'Java Builder' on project 'XXX'

We are unable to build the workspace in Eclipse Kepler. It's throwing  Errors occurred during the build. Errors running builder 'Java Builder' on project 'XXX'. java.lang.NullPointerException   error while building project.  Even after checking the Eclipse log, we are unable to fix it. Please find below eclipse log:  !MESSAGE Errors running builder 'Java Builder' on project 'TRi2V3'. !STACK 0 java.lang.NullPointerException     at com.dell.toadext.javaeditor.ui.sqlmarker.AstResource.addStringLiteral(AstResource.java:153)     at com.dell.toadext.javaeditor.ui.nodeResolvers.MethodInvocationResolver.resolveSetLengthBuilderMethod(MethodInvocationResolver.java:151)     at com.dell.toadext.javaeditor.ui.nodeResolvers.MethodInvocationResolver.resolveBuilderMethod(MethodInvocationResolver.java:100) .......   Could you please suggest the solution to fix it.


If $x$ is rational then $\,x+\frac{1}x \,$ is an integer $\iff x = \pm 1$

Show that $X+\dfrac{1}{X}$ is not an integer number for any rational $X$ and $X \neq 1, X \neq -1$    I think we can substitue $X=\dfrac{P}{Q}$ but I don't know if I can now assume that $\gcd(P,Q)=1$


Let $a,b,c$ be positive reals such that $abc = 1$. Prove that $\sum_{\text{cyc}} \frac{1}{b(a+b)} \ge \frac{3}{2}$.  Well, I tried like this before : Since $abc=1$, the inequality can then be written as $$\sum_{\text{cyc}} \frac{ac}{a+b} \ge \frac{3}{2}$$ But then, I don't know how to manipulate further so that I can use the AM-GM inequality, or maybe others such as Cauchy Schwarz, etc. Can anyone help? That will be really appreciated! Thanks a lot!


let $A$ be a matrix $m\times n$ if The colums of $A$ Span $\mathbb{R}^m$ then the equation $Ax=b$ will have an answer for all $b\in \mathbb{R}^m$

I can't understand why this is true, Intuitively, I thought that it should be the rows of A span all $\mathbb{R}^m$ , so they don't become zeros while row deducting. Can someone help me understand this? Thanks


Looking for a book, wormhole, space ship Crash landing

From what I remember of the book:   A spaceship goes through a wormhole (I think) and crash lands on a planet They salvage what they can from the ship and build a castle on a mountain, cutting the stone with the lasers from the crashed ship The crew develop some sort of powers, the captain (She) seems to develop some sort of Precognition The planet's inhabitants where men rule and women are second class citizens Some women escape to the crew's castle so they can be equal citizens After they build the castle the crew fight the inhabitants the that came to attack them   What is the name of this book?


Is it possible to package dependencies in .jar

I was wondering if it is possible to "package in" dependencies while using mvn compile.  When I do compile my program with mvn install I do get clean and great result as expected, but after I package it into .jar suddenly I get missing classes exceptions.  I have read that it may be caused by differences in build and package class paths but I am unable to fix it.    Thanks a lot.


Is the additional damage die from the Wild Magic sorcerer's Spell Bombardment feature doubled on a crit?

At level 18,  get the  feature (PHB, p. 103):     Beginning at 18th level, when you roll damage for a spell and roll the highest number possible on any of the dice, choose one of those dice, roll it again and add that roll to the damage. You can use the feature only once per turn.   When you score a critical hit with an attack (even a spell attack), you double the amount of dice you roll.  Does the additional damage die from Spell Bombardment also get rolled twice on a critical hit?


How do I add a normal text with a Count fomula in the same cell?

I've tried using this: =countif(B2:B200, "<Open>")  And it ends up looking like this:  I want it to look like this:  Or something similar to that. Basically I want to include the word "Open" and the number count of cells B2:B100 Can someone please help?


What are: province, territory, protectorate, state...?

Often a country will have regions called "provinces" or "states". Other times they are called "territories" and "protectorates".   Is there a generic term for these words?  Is there a full list of words that belong to this group?  What makes them different from each other?


Is it possible for a binary classifier to have lower accuracy, macrof1 and binaryf1 but higher ROC AUC?

I've got the results of two classifiers based on 5 different splits of training and testing sets. Their mean and std of the results are as follow: Method-------Accuracy -- MacroF1 -- BinaryF1---- ROC AUC Classifier1 0.71±0.032 0.57±0.058     0.33±0.133     0.46±0.095 Classifier2 0.58±0.178 0.44±0.134 0.26±0.137 0.56±0.063 Is this a possible situation? The first three metrics are better in the first classifier and the last one is better for the second classifier. Is this a possible situation? Thanks


Ubuntu 12.04.2 Installation Problem: Can't boot or Use WUBI

I am a Windows user, but want to use Ubuntu now.  For this I have downloaded Ubuntu 64-bit from the Ubuntu site. But, I am not able to install it. I have tried both, booting from it as to clean install and through Wubi.  While booting from Ubuntu, all I got was a black screen with a circle, an '=' image and small human like image. It remains there for a while and thereafter an error message Uncompression failed -- System Halted appears and system reboot.  Here are last few lines of error log:  08-14 15:58 ERROR  TaskList: Non fatal error [Errno 4] IOError: <urlopen error (7, 'getaddrinfo failed')> in task download 08-14 15:58 DEBUG  TaskList: ### Finished download 08-14 15:58 ERROR  TaskList: Could not retrieve the required disk image files Traceback (most recent call last):   File "\lib\wubi\backends\common\tasklist.py", line 197, in __call__   File "\lib\wubi\backends\common\backend.py", line 592, in get_diskimage Exception: Could not retrieve the required disk image files 08-14 15:58 DEBUG  TaskList: # Cancelling tasklist 08-14 15:58 DEBUG  TaskList: # Finished tasklist 08-14 15:58 ERROR  root: Could not retrieve the required disk image files Traceback (most recent call last):   File "\lib\wubi\application.py", line 58, in run   File "\lib\wubi\application.py", line 132, in select_task   File "\lib\wubi\application.py", line 158, in run_installer   File "\lib\wubi\backends\common\tasklist.py", line 197, in __call__   File "\lib\wubi\backends\common\backend.py", line 592, in get_diskimage Exception: Could not retrieve the required disk image files   While trying with Wubi, it gives error Could not retrieve the required disk image files. Whereas I have complete Ubuntu desktop installed.  Please guide me through this as I really want to move to Ubuntu.  Please do not suggest that I have to  download it again, as I have a very slow data connection.  One thing I would like to share, is that I didn't downloaded the setup in one go, but many a times by resuming as my net connection is very bad.  My laptop is Dell Inspiron 3521 with Windows 7 Ultimate 32-bit trial version is installed in it. But it is of 64 bit architecture.  EDIT: Just checked on my other desktop and it has same problem. Though my desktop is of 32 bit architecture, so there had to be incompatibilty. Do you think it could be because OS on my laptop is 32 bit or trial version?????


I am trying dual boot Ubuntu with Windows 10. This installation was going Like Breeze until GRUB Installation.  Partition Specs:-  Boot was 100GB Swap 16GB Home ext4 100GB     All those partitions are NOT primary. Home Is Logical.


Sklearn - Choosing the right model for supervised learning/classification task

I am beginning to learn how to use scikit-learn and I have a hard time choosing the right model.  Here is my dataset: I have 100 persons. Each person was measured three times: baseline, first event and second event. Each measurement had 100 different markers per person that range from 0.1 to 1000. Additionally I have outcome measurements of each event: outcome can be 0, 1 or 2. My task is to find just a few markers (let’s say 10) that can predict outcome with a good accuracy. If I am right it should be: Supervised learning/Classification problem. What model would be the best?  Thanks for your help!


Using a custom TrueType font in spans of text

I am putting together a book using pdfTeX (from the TeX Live distribution on OSX), and part of the book involves a fictional dictionary for a constructed language. What I would like to do is define a command called, say, \conlang which switches to what is essentially a symbol font for the duration of that command. The .ttf also needs to be embedded in the .pdf.  I have found a number of tutorials on how to change the font family for the entire book, and I have found tutorials on how to change the font when using a package-specified font, but nothing for how to build the commands that actually load the fontfamily and make it available without building an entire package.


How to prove: $\int\limits_0^1 \frac{|f''(x)|}{f(x)}dx>4,$ using elementary math tools.

Let $f\in C^2 [0,1]$ and $f(0)=0=f(1)$ and for all $x\in (0,1)$ we have $f(x)>0$. Prove that     $$ \int_0^1 \dfrac{|f''(x)|}{f(x)}dx>4.$$   I want to prove this problem with elementary math tools. It is given to the first year university students as a calculus exercise. It is noticed that:  Hint: Use average value theorem in suitable intervals.