I've declared my attack, and my opponent declares their blocker. I then use an instant that boosts and gives first strike to my attacking creature, then in the middle of combat they tap the creature to activate its ability. Can they do this?

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?


I will be going to Switzerland soon, and will need Swiss Francs before I leave.  Where can I bet the best rate to buy Swiss Francs?  I live in SF Bay Area.

Recently my wife and I traveled to Italy and before we left we got about 85% of our money in travelers checks and the other 15% we carried on in cash. When we arrived there, no one would take our travelers checks and many places did not accept credit cards. Eventually, we found some currency exchange places that would take the travelers checks and give us Euro's, but at a 7-15% fee, which was not really a very fun surprise.   While I was under the impression that it is safer to use travelers checks, it seems that they were not really accepted (the usual explanation being fraud). So the question is, is it best to just exchange your currency at home and carry all of it with you when you travel or are there other alternatives to carrying cash that are safer and cost effective?


When LIGO said one merging black hole was thirty or so solar masses, the other twenty, and that they were one billion light years away;   how do they know that?

The  was observed, giving us the frequency and amplitude of the event. Because LIGO has two detectors a  could be derived.  But how do these three factors allow for the mass of the black holes and their distance to be calculcated? If the wave strengths are in a square relationship to distance, then couldn't there be an infinite number of other masses and distances which would give the same signals?


I am building a small JavaScript game where the user has to guess a word. The user will be given letters and he will have to combine them into a word. Every time when the user adds/removes a letter, the system checks if the word combined is the answer.  As the game will be mostly presented to users with no programming skills and because my server is not too powerful, I decided to implement word checking on the client side. (otherwise, I would have to run an ajax request for php script which possibly checks the answer from mysql db. that would introduce extra latency and load on the server)  Now, just to make sure, I would like to make it a bit more difficult for users with low programming skills to find out the answer variable or see the comparing function.  Is it somehow possible to make a function in JavaScript non-human readable? Or at least making it hard-readable?    Just to remind you again, I am not too concerned if the final code will be not secure enough and some people actually crack the compare function and get the answer - I would be happy for their effort.

I want to make a JavaScript application that's not open source, and thus I wish to learn how to can obfuscate my JS code? Is this possible?


Let $\theta = 2\pi/67$. Now consider the matrix   $$  A =  \begin{pmatrix}   \phantom{-}\cos \theta & \sin \theta \\   -\sin \theta & \cos \theta  \end{pmatrix}. $$   Then the matrix $A^{2010}$ is      \begin{align*}  &\text{(A)}\;  \begin{pmatrix}   \phantom{-}\cos \theta & \sin \theta \\    -\sin \theta & \cos \theta  \end{pmatrix},  &  &\text{(B)}\;  \begin{pmatrix}   1 & 0 \\   0 & 1  \end{pmatrix}, \\  &\text{(C)}\;  \begin{pmatrix}   \phantom{-}\cos^{30} \theta & \sin^{30} \theta \\    -\sin^{30} \theta & \cos^{30} \theta  \end{pmatrix},  &  &\text{(D)}\;  \begin{pmatrix}   \phantom{-}0 & 1 \\   -1 & 0  \end{pmatrix}. \end{align*}   I think answer is B. But I am not sure.

Let $\theta=\frac{2 \pi}{67}$. Consider the matrix   $$A = \begin{pmatrix} \cos\theta  & \sin\theta\\   -\sin \theta&  \cos \theta \end{pmatrix} $$   Then the matrix $A^{2010}$ is?   My approach $$A^2 = \begin{pmatrix} \cos2\theta  & \sin2\theta\\   -\sin 2\theta&  \cos 2\theta \end{pmatrix} $$  $2010$ is a multiple of $67$. So I'm trying to convert in such format by taking $A$ matrix as power of $2$ and multiplying. But $2048$ is the nearest $2$ power term. So help please. I dont know if you can understand what I did!! Sorry for being not explaining properly


Intuitively I used to think that a $1\times 1$ matrix is simply a scalar number, I also saw this statement in books. However when I think about it now it doesn't make sense to me because of one problem.   Let $I$ be the $2\times 2 $ identity matrix, now $\lambda I$ is well defined if $\lambda $ is a scalar or if $\lambda $ is a $1 \times 2$ matrix. However if we want to make the statement that scalars and $1 \times 1$ matrices are the same then the $\lambda I$ would have to be defined for a matrix $\lambda$ which is not $1 \times 2$.   More generally, let $M \in \Bbb R^{n \times m}$, now linear algebra says that if $N$ is another matrix, the product $NM$ only exists if $N \in \Bbb R^{m \times n}$. However if $n$ and $m$ are not zero then $NM$ is not defined for a $1\times 1$ matrix $N$, while $NM$ is defined if $N$ is simply a scalar... So in conclusion we can simply state that $1\times 1$ matrices and scalars are not the same thing right? Is there any interesting theory behind this?

I was wondering. Clearly, we cannot multiply a (1x1)-matrix with a (4x3)-matrix; However, we can multiply a scalar with a matrix. This suggests a difference.  On the other hand, I was, for example, in an econometrics lecture today, where we had for a (Tx1)-vector $\underline{û}=\left( \begin{array}{c} û_1\\ \vdots\\ û_T\end{array}\right)$:     $S_{ûû}:= \sum_{i=1}^T û_i^2$ shall be minimized. We see see that   $S_{ûû}=\underline{û}^T\underline{û}$.   Well, formally, shouldn't it be $(S_{ûû})=\underline{û}^T\underline{û}$ or $S_{ûû}=\det(\underline{û}^T\underline{û})$, to ensure that we stay in the space of matrices and not suddenly go to the space of scalars? So here, the professor (physicist) not only treats $\underline{û}^T\underline{û}$ like a scalar, but also calls it a scalar. Is this formally legit or a wrong simplification (though it does not seem to have any impact, and surely makes life easier)?


So I was coding a simple game where the computer guesses a number you are thinking of between 1 and 1000. The code is as follows hwoever whenever I run this, no matter what i tell the computer wether i say higher or lower, it never updates the minimum and maximum to narrow in on the answer, ye the logic looks correct to me. :  package com.company; import java.util.*;    public class Main {      public static void main(String[] args) {         //set and initialize variables         int currentGuess;         int min = 0;         int max = 1000;         boolean guessedCorrectly = false;         String userInput;         Random rand = new Random();          //Create user input object         Scanner user_input = new Scanner(System.in);          //Explain Game Rules to User         System.out.println("Please think of a number and I will try to guess it.");         System.out.println("You can respond h for higher, l for lower, and c for correct: ");          //Main Game Loop         while (guessedCorrectly == false){             currentGuess = min + rand.nextInt(max - min + 1);             System.out.print("Is your number " + currentGuess);             userInput = user_input.next();             if (userInput == "h"){                 min = currentGuess;             }else if (userInput =="l"){                 max = currentGuess;             }else if (userInput == "c"){                 guessedCorrectly = true;             }else{                 System.out.println("Please enter an h for higher, l for lower, or c for correct ");             }           }         System.out.println("Congratulations to MEEEEEE, I guessed it correctly!");     } }   Any Ideas?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I'm fairly certain this has happened to all of us at some point: You go into a room to get something, but once you're there, you can't remember what you intended to get. It seems like a specific, common phenomenon like this must have a name, but I can't think of it. Does anyone know a name (either formal or slang) for this?  I don't want a general term like forgetfulness or absent-mindedness, which could apply to all sorts of forgetting, or a term for not being able to remember a certain word. I'm looking for a word or phrase that describes this one specific situation of forgetting what you need to get as soon as you go to get it.

You know when you feel like you need to do something but you can't remember what it is?  You almost feel a little anxious because you can't remember what you were going to do / what you need to do.  Is there a name for this feeling?


Background  When I attempt questions in real analysis, frequently I encounter the following expression like harmonic series:   $$H_n=1+\frac{1}{2} + \frac{1}{3} + \dots + \frac{1}{n}$$  To my surprise when I arrive at something like this ,the solution book does not give me a closed-form of this expression.   Question   So my question is a simple one. What can you think of for this series? And besides the fact that it does not converge is it related to any mathematics that you know? And most importantly, does it have a closed-form?

One of the joys of high-school mathematics is summing a complicated series to get a “closed-form” expression. And of course many of us have tried summing the harmonic series $H_n =\sum \limits_{k \leq n} \frac{1}{k}$, and failed. But should we necessarily fail?      More precisely, is it known that $H_n$ cannot be written in terms of the elementary functions, say, the rational functions, $\exp(x)$ and $\ln x$? If so, how is such a theorem proved?    Note. When I started writing the question, I was going to ask if it is known that the harmonic function cannot be represented simply as a rational function? But this is easy to see, since $H_n$ grows like $\ln n+O(1)$, whereas no rational function grows logarithmically.  Added note: This  asks a similar question for “elementary integration”. I guess I am asking if there is an analogous theory of “elementary summation”.


Can a lightsaber's blade length be changed after it's built or is it fixed upon construction of the lightsaber?

I always see blades of lightsabers have more or less the same length (dual blades are double). Why is that?  Can't a longer or shorter length be advantage in some case?    I am NOT expecting infinite length lightsabers (due to energy issues), but have we seen adjustable length blades in the Canon?


When n and m are both positive integers, to show that $a^n  a^m = a^{n+m}$ will be pretty straightforward:  $$a^n  a^m = (\underbrace{a\cdot a\cdots a}_{n\text{ copies}})(\underbrace{a\cdot a\cdots a}_{m\text{ copies}}) = (\underbrace{a\cdot a\cdots a}_{n+m\text{ copies}})= a^{n+m}$$  Now suppose that, for example, $n \in \mathbb R$ and $0 < n < 1$ and $m \in \mathbb R$  How do you show that $a^na^m = a^{n+m}$ in that scenario too?

For all $ a, b \text{ and } c \in \mathbb{R}$ and $a>1$, Prove that $a^b\cdot a^c=a^{b+c}$  I have come across this question and its  bugging me. Its a basic property that we learn in HS  and I was hoping someone can enlighten me


How can i possibly do this without knowing the size of the array beforehand? I'm totally confused. I've been trying to do this by splitting the array and what not but it's supposed to do this by using only loops. Here's different ways I've tried to do it but it doesn't stop taking user input even when it encounters a *.  1st version:  import java.util.*; public class Number11 {  public static void main(String[] args) {       String line="";     Scanner input = new Scanner(System.in);      System.out.println("You are asked to enter a character one by one and terminate the list with *");      System.out.print("Please enter a character or end it with * : ");     line = input.next();     while(!(line.equals("*")))     {         System.out.print("Please enter a character or end it with * : ");         line = input.next();         if(line.equals("*"))         {         System.exit(0);         int length = line.length();         String [] sequence = new String[length-1];         for(int i=0; i<length; i++)         {             sequence[i] = line;         }         break;         }     }   }  }   2nd:  import java.util.*; public class Number11 {  public static void main(String[] args) {      String [] character = new String[20];      Scanner input = new Scanner(System.in);      for(int i=0; i < character.length; i++)     {         System.out.print("Enter a character or press * to stop: ");         character[i] = input.next();         while(!(character[i].equals("*")))         {             System.out.print("Enter another character or press * to stop: ");             character[i] = input.next();         }      }  }  }   Your help will be much appreciated. Thanks.


I am using the theme TwentyTwelve and modified the standard post query in the file author.php with the following code:  function wpd_author_query( $query ) { //CODE to set $current_user_name here //This gets the author from the URL $author = get_user_by('slug',get_query_var('author_name')); $current_user_name = $author->user_nicename;      if ( $query->is_author() && $query->is_main_query()) {             // your code to set $current_user_name here             $query->set( 'meta_key', '_writer_relation_added_date_'.$current_user_name );             $query->set( 'orderby', 'meta_value_num' );             $query->set( 'post_status', $post_status );              $tax_query = array(                   array(                     'taxonomy' => 'writer',                     'field' => 'name',                     'terms' => $current_user_name                 )             );             $query->set( 'tax_query', $tax_query );     }                } add_action( 'pre_get_posts', 'wpd_author_query' );   However, the tax_query is not working for the author page. It is still not retrieving the posts in the writer taxonomy.  I did try applying that code for other pages such as is_home() is_archive() and it does work.  So, there must be a conflict in with wordpress and the author template page that is not allowing me to use the tax_query for retrieving posts in the writer taxonomy.

I have added a custom/secondary query to a template file/custom page template; how can I make WordPress use my custom query for pagination, instead of using the main query loop's pagination?  Addendum  I have modified the main loop query via . Why isn't pagination working, and how do I fix it?


Let $R$ be a ring such that every $x$ satisfying $x^n = x$ for some $n > 1$. Show that every prime ideal in $R$ is maximal.

Let R be a commutative ring with an identity such that for all $r\in$ R, there exists some $n>1$ such that $r^n = r$. Show that any prime ideal is  maximal. (Atiyah and MacDonald, Introduction to Commutative Algebra, Chapter 1, Exercise 7.)    Any hints?


making some simple tries about initializations (and default constructors) of object and primitives in C++, I found a behaviour that I don't understand, so I need an help.  Let's first talk about primitives types.  The code I tested is the following:  int main() {      int i(5);     cout<<i<<endl;      int j();     cout<<j<<endl;      int k;     cout<<k<<endl;      return 0; }   The result I get is this:  5 1 6487956   Obviously I was especting the first result (initialization in object style), and also the third (not initialized value), but the second? About the second, I was especting a default initialization, instead I get a warning that told "the address of 'int j()' will always evaluate as 'true'"... Infact the printed result is 1, but what kind of sintax is the empty round brackets near a primitive variable?  And now about the object, the case is similar... The code is:  class Pluto { public:     int a;     int b;     Pluto() {         a = 0;         b = 0;         std::cout<<"Constructor call"<<std::endl;     } }  int main() {     Pluto p(); }   I have a class with a default constructor inside which I've put a print to underline its invocation, then I declare an object with a similar sintax to the previous case, and I was expecting a call to the default constructor, while I get nothing in output, so the constructor was not called. In a next test, I try to access the members of the object, but I get the error "Field 'a' could not be resolved".  I'm sure that the anwer to my question is stupid and obvious, but now I really can't find it, so thanks to who will help me.

Is there any good reason that an empty set of round brackets (parentheses) isn't valid for calling the default constructor in C++?  MyObject  object;  // ok - default ctor MyObject  object(blah); // ok  MyObject  object();  // error   I seem to type "()" automatically everytime. Is there a good reason this isn't allowed?


I have a SQL Server 2016 Enterprise database server that I have recently inherited.  One instance on this server has an application that uses two different databases.  One of these is the actual application database and the other is used to generate reports and dump data from the first.  The second database has several stored procedures that run at different times, including one that dumps data from a view into a CSV file for offsite storage of the data that runs every 15 minutes.  When I initially got this database, the recovery model was set to simple and a database backup was being taken nightly.  Since, I have changed the recovery model to full and changed the backup plan so that it is taking full backups twice weekly, differential backups twice daily and log backups every three hours.  However, even with this change, the transaction log for the second database is staying around 300GB.  Each transaction log backup is around 80GB.    I have plans to dig into how the stored procedures work and hopefully simplify some the way these things run, but that is going to be a long term project.  In the short term, I need to find a way to determine if the transaction log is being truncated correctly and if there is anything I can do to reduce the size of the transaction log on this database.  I've looked at the log with the fn_dblog function hoping to see if there were old transactions being stored, but most of the Begin Time and End Time records are null.    Other than a complete rewrite of the system (which is in the works), does anyone have any suggestions for getting a handle on this log file?

This one seems to be a common question in most forums and all over the web, it is asked here in many formats that typically sound like this:  In SQL Server -  What are some reasons the transaction log grows so large? Why is my log file so big? What are some ways to prevent this problem from occurring? What do I do when I get myself on track with the underlying cause and want to put my transaction log file to a healthy size?


For the ordinal space $ω_{(1)}$, the Stone-Cech compactification and the one-point compactification coincide. What is another such space?

This question is a follow up question to  Definition 1. A non-compact Hausdorff topological space X is called almost compact if its Stone-Cech compactification coincides with its one point compactification. The only two examples of almost compact spaces I know are from the book . On the page 17 authors say that $[0,\omega_1)$ is almost compact and Mrowka-Isbell space $\Psi(\mathcal{A})$ is almost compact for some specific maximal almost disjoint family $\mathcal{A}\subset 2^\omega$. I would like to know more on almost compact spaces, but I found almost nothing on this subject. Questions:  What are other examples of almost compact spaces? Is true that $\beta\mathbb{N}\setminus\{p\}$ is almost compact for $p\in\beta\mathbb{N}\setminus\mathbb{N}$ ? Is it true that $X\setminus \{p\}$ is almost compact whenever $X$ is extremally disconnected and $p\in X$.


I'm clueless about the Jedi, and I wanted to know - can you be a Jedi at fifteen? When you started training at five? If your midichlorian count is 13,200? How old do you at least have to be to be a Jedi? How long does it take to train?

Anakin Skywalker was about nine years old (see script link, below) during "The Phantom Menace". Yet according to various people, he was too old (or even "far too old") to begin training as a Jedi:   QUI-GON: "I'm afraid not. Had he been born in the Republic, we would have identified him early, and he would have become Jedi, no doubt...he has the way. But it's too late for him now, he's too old." OBI-WAN: "The boy will not pass the Council's tests, Master, and you know it. He is far too old." MACE WINDU: "He is too old. There is already too much anger in him." and even ANAKIN himself: "I'm with Qui-Gon...but...they're not going to let me be a Jedi. I'm too old."   All quotes above from .  However, during "The Empire Strikes Back" Yoda gives Luke's age (18 in chapter IV according to the ) as the reason to deny him training only after first saying that Luke is:   too impatient too angry not ready is unfocused ("Never his mind on where he was") and reckless   All from .  I would have thought that, if at 9 Anakin was too old, Yoda would have seen Luke at 18+ and started off by saying, "No chance, he has".  So, what is the age to begin Jedi training?


describe syntax is not working in PLSql :  I am using below syntax :  DESCRIBE tblcustomer;   I am getting below exception after executing above query :  ERROR:  syntax error at or near "DESCRIBE" LINE 1: DESCRIBE tblcustomer;         ^  ********** Error **********  ERROR: syntax error at or near "DESCRIBE" SQL state: 42601 Character: 1

How do you perform the equivalent of Oracle's DESCRIBE TABLE in PostgreSQL (using the psql command)?


The Greeks call their country Hellas and themselves Hellenes.   The names Greece and Greek are of Roman origin and were adopted from Latin Graecus into old High German as Crêch and then in all Germanic languages the name was fashioned after the Latin -  Old English Grécas. (See OED extract below)  It has been the policy of the international community for many years to name new countries, (and rename old ones), to correspond with the way they are known to their own government and population. Thus Abyssinia became Ethiopia, the Gold Coast became Ghana, Rhodesia became (after partition) Zambia and Zimbabwe. (For a more complete list of name changes go to .)   Since there may be some evidence that it was only colonists (presumably from Rome to Euboea) that assigned the name Greece, why do we continue to use that name and why not Hellas?  After all we no longer refer to the USA as The thirteen colonies.        Forms:  pl.OE Cré(a)cas, Gré(a)cas, ME Greckes, Orm. Grickess, ME   Greks, Grekis, ME Grekys... (Show More) Etymology:  In branch I: The   Old English Crécas plural, corresponds to Old High German Chrêch ,   Chriech (Middle High German Kriech ), Gothic Krêks < *Krêko-z , an   early Germanic adoption of Latin Graecus , plural Graecī (see below),   the name applied by the Romans to the people called by themselves   Ἕλληνες . The substitution of k for g is commonly accounted for by the   supposition that the Germanic initial g , when the word was adopted,   still retained its original pronunciation /ɣ/ , so that k would be the   Germanic sound nearest to the Latin g . In all the Germanic languages   the word was ultimately refashioned after Latin, with change of k into   g ; hence Old English Grécas plural beside Crécas , Middle Dutch   Grieke (Dutch Griek ), modern German Grieche , Old Norse Grikkir ,   plural. In branch II the noun is an absolute use of Greek adj. The   Latin Graecī is < Greek Γραικοί, said by Aristotle ( Meteor. i. xiv)   to have been the prehistoric name of the Hellenes in their original   seats in Epirus. The word is apparently an adjectival derivative of   Graius, which is used in Latin as a poetical synonym of Graecus.   Recent scholars think the name may have been brought to Italy by   colonists from Euboea, where there is some evidence of its having   existed: see Busolt Gr. Gesch. I.2 198. (Show Less)  I.

The Greeks I've met say something that to my ears sounds like 'Elatha'.


Using the instructions from  I upgraded from texlive 2014 to texlive 2016 on my second laptop. I did this because I am using some more recent packages and I don't think they will work with texlive 2014.    Now I do not seem to have the ability to add anything to my tex tree, which in my case is located at:  /usr/local/texlive/2016/texmf-dist*  So after adding to my tex tree, I did sudo texhash  kpsewhich picks up the 2016 packages fine, but I do not seem to be able to add anything.  I also tried adding a directory ~/texmf putting the files in there and then doing texhash ~/texmf and still no joy.  sudo texhash produced:  texhash: Updating /usr/local/share/texmf/ls-R...  texhash: Updating /var/lib/texmf/ls-R-TEXLIVEDIST...  texhash: Updating /var/lib/texmf/ls-R-TEXMFMAIN...  texhash: Updating /var/lib/texmf/ls-R...    Does anybody know what can be done to fix the situation?  I would be mightily obliged to any kind person who might help me figure out a solution.  Thanks.   Adding:  alias sudo='sudo env PATH=$PATH'   and then running  mktexlsr as suggested in  had no effect (I logged out and logged in again)

So, I'm running linux Mint (but I guess the same applies to Ubuntu) and as is common knowledge, their TeX distribution tends to be slightly outdated. Now I can't have none of that and decide to install it with the install-tl from the TeXlive homepage. Somehow, I cannot install it as a normal user (this I find normal as it is installing in the root directory), so I proceed to install TeXlive   sudo perl ./install-tl   and add the paths to .bashrc. All is well and my TeXlive installation works. Except for the texhash option. Running it as a normal user is no problem, except that I installed TeXlive as root, and so running texhash as normal user doesn't do anything (directory not writable. Skipping...). No problem I think, I'll just do it as root. But somehow texhash isn't installed for root.  Now, texhash is somehow connected to updating the directory tree, but I don't really know what it does. I use it on my ~/texmf/ folder to add my packages to a global path (I think), but when looking at info for this question I see in a comment for  question that this is apparently not needed, though I don't understand what I'm to do now.  So if I'm not adding new packages from CTAN or updating, I really don't need texhash and all is good?   To summarize: I'd like to know:    Why should I need texhash? Can I avoid installing as root on linux Mint/ubuntu ( they say you don't have to be root, that it's even discouraged)? Should I somehow install texhash for root?   I realize this might be a vague question at best, but I didn't find an answer I readily understood, so I'd appreciate any thought on this.


Good evening (or morning). Now I'm working on my own comics. There is the plot: A samurai-girl was stolen and was a slave in Ryeo for 6 years. Then she became empress of Yuan Empire. She hit in time portal and fought with five monsters to save emperor's life. But when she fought, she became samurai again. In the end, she learned that she is Korean king's daughter, who was sold to Japanese merchants in childhood. The question: this is a manga, manhua or manhwa? Thanks in advance!

I understand that manga is from Japan and read from right to left, whereas manhwa is from Korea, read from left to right, and manhua is from China, and read from right to left (If I'm not mistaken). Are these the only differences between the three, or is there something else?


I know that there is no difference in 0022 and 022 referring to . I have file 1.c, with permissions 0066. But when I change the mode of file 1.c to 1066, and then when I check the permissions of file with ls -l, it effects the permissions.  Each time different permission bits are changing with change in this first digit. What actually it signifies?  [vm4 ~]# ls -l 1.c ----rw-rw- 1 root root 10 Dec 23 22:48 1.c [vm4 ~]# chmod 1066 1.c [vm4 ~]# ls -l 1.c ----rw-rwT 1 root root 10 Dec 23 22:48 1.c [vm4 ~]# chmod 2066 1.c [vm4 ~]# ls -l 1.c ----rwSrw- 1 root root 10 Dec 23 22:48 1.c [vm4 ~]# chmod 5066 1.c [vm4 ~]# ls -l 1.c ---Srw-rwT 1 root root 10 Dec 23 22:48 1.c

I've never really got how chmod worked up until today. I followed a tutorial that explained a big deal to me.   For example, I've read that you've got three different permission groups:   owner (u) group (g) everyone (o)   Based on these three groups, I now know that:   If the file is owned by the user, the user permissions determine the access. If the group of the file is the same as the user's group, the group permission determine the access. If the user is not the file owner, and is not in the group, then the other permission is used.   I've also learned that you've got the following permissions:   read (r) write (w) execute (x)   I created a directory to test my newly acquired knowledge:  mkdir test   Then I did some tests:  chmod u+rwx test/ # drwx------ chmod g+rx test/ # drwxr-x--- chmod u-x test/ # drw-r-x---   After fooling around for some time I think I finally got the hang of chmod and the way you set permission using this command.    But...  I still have a few questions:   What does the d at the start stand for? What's the name and use of the containing slot and what other values can it hold? How can I set and unset it? What is the value for this d? (As you only have 7=4+2+1 7=4+2+1 7=4+2+1) Why do people sometimes use 0777 instead of 777 to set their permissions?   But as I shouldn't be asking multiple questions, I'll try to ask it in one question.  In UNIX based system such as all Linux distributions, concerning the permissions, what does the first part (d) stand for and what's the use for this part of the permissions?


Does anyone how many times a year one can enter and exit and RE-ENTER Morocco as a United States passport holder? For instance, Schengen countries have the 90/180 rule. I've looked everywhere for the information and there is nothing out there, making me think it's a non-issue, but I'd like to make sure!

I arrived in Morocco in October of 2014 and renewed my visa by traveling to Spain by ship for a day and getting my passport stamped again in January of 2015. My question is, am I allowed to leave the country and repeat this process this year by traveling again to another country, other than my own in order to return to Morocco for another 90 days? And if so, how many times a year is this allowed? I have read 180 days on some websites but there is not any clear answers anywhere about this that I can find.


i have 2 numbers with decimals  var a = 455.7530 var b = 544.8025  var k = parseFloat(a)+parseFloat(b)  Expected Output is 1000.5555 Actual Output is 1000.5554999999999   Please advice which method i should use to add two numbers with decimal

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


Let $1<p<\infty,$show that  $$\bigg(\int_{0}^{\infty}\bigg(\frac{1}{x}\int_{0}^{x}|f(t)|dt\bigg)^{p}dx\bigg)^{\frac{1}{p}}\le\frac{p}{p-1}\lVert f\rVert_{L^{p}(0,\infty)}$$  Here is my attempt :  \begin{align} \bigg(\int_{0}^{\infty}\bigg(\frac{1}{x}\int_{0}^{x}|f(t)|dt\bigg)^{p}dx\bigg)^{\frac{1}{p}}&\le\int_{0}^{\infty}\bigg(\int_{t}^{\infty}\frac{|f(t)|^{p}}{x^{p}}~dx\bigg)^{\frac{1}{p}}dt\\ &\le\int_{0}^{\infty}\bigg(|f(t)|^{p}\int_{t}^{\infty}\frac{1}{x^{p}}~dx\bigg)^{\frac{1}{p}}dt\\ &=\int_{0}^{\infty}\bigg(|f(t)|^{p}\frac{t^{1-p}}{p-1}\bigg)^{\frac{1}{p}}dt \end{align}  ,where the first I used minkowski inequality of integral form.  Then I stuck with it . But I got a hint to apply the convolution with some function .  Is there anybody that can show more details ? Thanks for considering my request .

I am trying to prove Hardy's Inequality for integrals:     Let $f:(0,\infty) \rightarrow \mathbb R$ be in $L^p$. Let $F(x) = \frac{1}{x} \int_0 ^x f(t)dt$. Then $F \in L^p$ and $\|F\|_p \leq \frac{p}{p-1} \|f\|_p$.    I have seen proofs of this which use Haar measure and Fourier analysis, eg. here . However, I am wondering if there is a more elementary proof.   I have tried to deduce this using Jensen's inequality and Fubini's Theorem as follows:  Jensen's inequality implies that $\left|\frac{1}{x} \int_0 ^x f(t)dt)\right|^p \leq \frac{1}{x} \int_0 ^x |f(t)|^p dt$. Therefore   $$\int_0 ^\infty |F(x)|^p dx \leq \int_0 ^\infty \frac{1}{x} \int_0 ^x |f(t)|^p dtdx = \int_0 ^\infty \int_t ^\infty \frac{1}{x} |f(t)|^p dx dt.$$  But, this last integral is infinite, and I'm not sure how to get a sharper bound on $|F(x)|^p$. Any suggestions?


I'm a complete electronics newbie.   I have a auto fish feeder that takes 2 AA (1.5V) batteries. After changing the batteries quite often I got curious to find out if the feeder can be modified to run using the electricity at home. Some research led me to find these:    The AC current has to be converted to DC An adapter is needed that converts 220V AC to 3V DC  I need a multimeter    So I looked around and found an adapter at home which says: Output:3VDC 1000mA 3VA. I actually have no clue what that means but I'm guessing that it will output the 3V required to run the auto feeder.   Bought a multimeter and used it to measure the output of the adapter. I was expecting to see 3.00.   Nope. I'm getting a reading of 6.46 every time.   So this is my question - is it OK to go ahead and wire the adapter to the fish feeder despite the higher reading? Will everything magically work or something is sure to blow up? Will adding some register help? I would've gone ahead to find out  if the feeder was available in my Country. I imported it from the US so I don't want to mess it up.   Could you guys please give me advice on how I can accomplish what I'm trying to do?  I'm totally ok to start from scratch.    EDIT: As for the adapter, it's from an electric shaver and this is how it looks:

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


Can I add color to column with colorbox or some other method that LaTex native?  What I want to display is below:    have tried  \begin{vmatrix} \quad 5 \qquad 1 \qquad \colorbox{grey}{1} \quad\\ \quad -6 \qquad 2 \qquad \colorbox{grey}{0} \quad\\ \quad -5 \qquad -5 \qquad \colorbox{grey}{0} \quad\\ \end{vmatrix}   and  \begin{vmatrix} \quad 5 \qquad 1 \qquad \bbox[grey, 20px]{1} \quad\\ \quad -6 \qquad 2 \qquad \bbox[grey, 20px]{0} \quad\\ \quad -5 \qquad -5 \qquad \bbox[grey, 20px]{0} \quad\\ \end{vmatrix}

I've found question , but the link to the documentation isn't helping me at all.  I'd like to know how to color a table column given my column code, but the documentation only gives the syntax of the command. It doesn't give any code example of where to use it.  \usepackage{colortbl}  \begin{table}[h]     \centering     \begin{tabular}{|c|c|c|c|c|c|c|c|}         \hline         \cellcolor[gray]{0.8}128&64&32&16&8&4&2&1\\\hline         1&0&1&1&0&1&0&1\\\hline     \end{tabular} \end{table}   As you can see, I got \cellcolor to work, but I don't want to color individual cells. I want to color a whole column of the table. Does anybody know how I can go about to do this?


I tried updating using update manager and I got error saying requires installation of untrusted package.  I tried typing get update and get upgrade command in terminal but no avail.  but following shows the result after "get update" in terminal.  W: GPG error: http:// archive.canonical.com precise Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com> W: GPG error: http:// archive.ubuntu.com precise Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com> W: GPG error: http:// dell.archive.canonical.com precise-dell Release: The following signatures were invalid: BADSIG F9FDA6BED73CDC22 Canonical Archive Automatic Signing Key <ftpmaster@canonical.com>   Here is screen shot for your reference     I am a very new user to ubuntu. Please help and explain as if you are explaining a child.

I frequently cross this issue, and always have to google for an answer. Does anyone have a permanent fix for BADSIG errors from apt-get?     W: GPG error:    lucid   Release: The following signatures were   invalid: BADSIG 54422A4B98AB5139   Oracle Corporation (VirtualBox archive   signing key)


HMAC seems a bit complicated. Why can't we use $H(m||k)$ as a MAC? Unlike $H(k||m)$, length extension attacks won't work.  Is there some other obvious attack?

Consider a common practically-collision-resistant hash function $\mathcal{H}$ (e.g. , , , ), perhaps based on the  as are the first three. We define a  $\mathcal{C}$ $$(k,m) \mapsto \mathcal{C}(k,m)=\mathcal{H}(m\mathbin\|k)$$ where $\mathbin\|$ denotes concatenation, $k$ is a secret key (constant, or at least of fixed size), and $m$ is a message (possibly of variable length). Assume that an adversary can (iteratively) submit queries with $m_j$ and obtain $C(k,m_j)$, and wants to obtain $k$ or otherwise compute $C(k,m)$ for some $m\ne m_j$.  That MAC $\mathcal{C}$ is not trivially bad. In particular, if $\mathcal{H}$ was indistinguishable from a random function in the , $\mathcal{C}$ would be secure. And even though $\mathcal{H}$ may have the , it does not turn into a devastating attack on $\mathcal{C}$.  The less impractical generic attack that I see is that if a collision was known for $\mathcal{H}$ with the colliding messages of moderate identical length, it could be deduced countless collisions for $\mathcal{C}$. Hence security is demonstrably not better than collision-resistance of $\mathcal{H}$ (for identical-length messages). We could assume that $k$ is half the size of the result of $\mathcal{H}$, and hope that the security is about  or  or , 280, 2128, 2256 hash rounds for SHA-1, RIPEMD-160, SHA-256, SHA-512.   What are the known attacks against $\mathcal{C}$ (better than the above), and their cost, for each of these common hashes?  Is there hope for an argument that an attack against $\mathcal{C}$ would turn into an attack of similar cost against $\mathcal{H}$, or hint of the contrary?  Update: this  is of interest, but I fail to find that it really answers the present question.  Update 2: I am aware that the construction considered is weaker than , and in particular is vulnerable to collision on $\mathcal H$; I stated that, and that it is thus pointless to have the key wider hopeless to target security against some attacks better than half the hash's size. I'm asking exactly what cryptanalytic attack better than finding a collision on $\mathcal H$ there are. There is room for such an attack only by exploiting a weakness in the structure or/and the round function of a concrete $\mathcal H$.


I'm dealing with a longitude array named LON, but I encountered some problems with the numpy.where() function.  >>> print LON[777,777] 13.4635573678 >>> print np.where(LON == 13.4635573678)[0] [] >>> print np.where(LON == 13.4635573678)[1] []   It doesn't find the LON entry where the array is equal to a value that certainly exists. Is the problem related to the fact I'm dealing with double variables? Because until now np.where() always worked fine for both integers, floats and strings...


There are some web apps that I decided not to install initially; I selected "Do not ask again" for the prompt.  Now that I have changed my mind, how do I go about installing that web app for a particular browser?

I'm using  and I accidentally clicked "No" when asked if I want to integrate with the website.  How can I have Firefox or Chrome reask me to integrate the site with Ubuntu?


Suppose $X$ and $Y$ are independent and identically distributed uniform r.v on $(0,1)$. Compute the joint density of $U=X+Y$ and $V =  \dfrac{X}{X+Y}$. How about if $X$ and $Y$ are iid exponential with $\lambda=1$?  Try Notice that $f_{X,Y}(x,y)=1$ and $X= V(X+Y)= UV $ and so $Y = U -X = U - UV = U(1-V)$. We compute the Jacobian of map $(U,V)$ and obtain $$ J = 1 \cdot \left( - \frac{X}{(X+Y)^2} \right) - 1 \cdot \left(  \frac{Y}{(X+Y)^2} \right) = - \frac{1}{X+Y} = \frac{-1}{U} $$ And since $$ f_{X,Y}(X,Y) = 1 $$ then $$ f_{U,V}(u,v) = f_{X,Y} (x,y) \frac{1}{|J|} = u $$ Since $0 \leq UV \leq 1$ and $0 \leq U(1-V) \leq 1$, we have $0 \leq U \leq \frac{1}{V}$ and $1 - V \leq \frac{1}{U}$ and so $1 - \frac{1}{U} \leq V \leq 1$ is this correct?

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


The below is my main method in which am comparing two object references. Having overridden the toString() method in Car class, my question is why are the below "if" conditions evaluating to false when they should evaluate to true. Could somebody explain? Thanks.  public static void main(String[] args){          Car c1 = new Car(2829,"white");         Car c2 = new Car(2829,"white");          if(c1 == c2)             System.out.println(true);         else             System.out.println(false);          String sc1 = c1.toString();         String sc2 = c2.toString();          if(sc1 == sc2)             System.out.println("it's equal");         else             System.out.println("it's not!");     }   public class Car {     private int regNo;     private String color;      protected void start(){         System.out.println("Car Started!");     }      public Car(int regNo, String color){         this.regNo = regNo;         this.color = color;     }      @Override     public String toString() {         return "Car-"+regNo;     } }   Say, i have two strings s1="abc" and s2 = "abc". Now, s1 == s2 evaluating to true then why is that in the above code c1.toString() == c2.toString() evaluating to false is my question?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I'm expecting 0.1 as a result but:  In [1]: 0.3 / 3  Out[1]: 0.09999999999999999   Tried with Decimal, nothing changed.  In [2]: from decimal import Decimal In [3]: Decimal(0.3) / Decimal(3) Out[3]: Decimal('0.09999999999999999629925658458')   What should I have to do to get correct result?

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


That's what this struggle, this isolation, this retreat is all about.   Should there be a comma after this retreat?  In the state above, it looks to me as if this struggle and this isolation are modifying this retreat, which isn't the sense of the sentence.   I was thinking that putting a comma after this retreat would make everything that follows this struggle to become enclosed in bracketing commas instead.  Is that the effect of adding the comma? And how are the commas currently functioning? They don't appear to be bracketing commas to me.

What are the rules on when to use commas, colons, semicolons and dashes?


Ubuntu 16.04 have support until April 2021. So in 2021 will i have to reinstall whole system or will be asked to update system by"system update like on windows" without formating hdd and losing all my preferences? Like every 5 years have to reinstall everything? Sorry to ask silly questions. I'm newcomer to Linux and I just want to use pc for daily things and don't want using terminal at all. Thank you

Question is about Ubuntu release process. Are migrations from n to n+1 releases expected?  Assuming we have server with installed Ubuntu 14.04 LTS. Will it be smoothly upgradable to Ubuntu 16.04 LTS via apt-get upgrade ?  Assumptions:   scope is software therefore we assume that given hardware is supported on both releases (upgrading from and to) that's why, always before upgrade you are asked to make backup to be able to revert in case of failure


There's a new notification about review queues that was added a few days ago. I think it is a good idea in general to remind users that the review queues exist. Every notification is a slight annoyance, but I think this one is a reasonable one on paper. But the actual implementation isn't reasonable, it's simply annoying for anyone using more than one SE site. The notification can be dismissed, but that dismissal isn't remembered network-wide, you have to dismiss it on every single site separately. I use several SE sites actively, and I also tend to occasionally browse the hot network questions for interesting or diverting content. Having to dismiss the same notification that often is just tedious. This isn't the first time a global notification that has to be dismissed per site was added. It also isn't the second or third time, this happens every single time SE adds something like this. Sometimes when we complain enough a network-wide option is added later, but never from the start. I know this isn't as simple technically as might appear, but it is possible. I don't think it is an unreasonable burden to include the work necessary for a proper network-wide dismissal for every kind of global notification SE adds. And if it appears too much effort to do that, is that notification really that important that you need to show it to everyone? Please just make dismissing notifications, popups and anything else like this always network-wide, and not just add this option after we complain on meta again. I'm just tired of complaining about this issue again and again.

The Public Platform team is continuing to work towards  and we’re here today to announce a new onboarding experience for the review queues. In the  (), we learned that each queues’ instructions could be easily misinterpreted and additional information was difficult to find. Without proper guidance or context, new reviewers would contribute inconsistent reviews and risk having their review privileges suspended. With this release, our goals were to 1) better highlight the review privilege and 2) provide upfront instruction and guidance for successful reviewing. New privilege announcements Community moderation is a significant aspect of Stack Overflow and the Stack Exchange sites. We want users to be aware and familiar with this newly earned privilege, but also celebrate the opportunity to contribute to the community in a unique way.  Many users were discovering the review queues by chance. Once the privilege is earned, a new review queue icon with a red alert would appear in the top-right part of the navigation. We are adding a popover to bring more attention to this easy-to-miss icon. We will also be adding notices for when users earn access to other, higher reputation queues. Additionally, new reviewers will also receive an email notification about the newly earned privilege. They will only get the email if they earn the privilege and don't perform a review within 24 hours (anyone who doesn't want to receive email notifications like this can visit their  and turn off "Tips and Reminders"). We are also showing a popover to users who earned access to review queues in the past, but have never done a review or haven't reviewed in the last 30 days. This popover is only appearing for the next 90 days. The goal is to engage users who may not have interacted with the queues since we made  and . Welcome banner  If a reviewer clicks “Learn more” on the on-page popover or goes to the review queue home page (/review), they’ll be greeted with an onboarding message with general information about the review queues. Informational modals  Queue-specific modals will appear upon page load as you visit each queue. They summarize and highlight important aspects and tips about reviewing in a particular queue. This information can be revisited at any time by clicking “Learn more” under the page header. Feedback As always, please leave your feedback and any bugs you may discover related to this release below this post. We will be monitoring this post for the next few weeks (May 4, 2021). After May 4th, please report any further issues as new questions.


I come to understand that there is some policy regarding users who repeatedly show little effort on their part when asking questions.  My questions   Is it correct? If so, what are the parameters by which a user is measured as showing little effort continuously? Recently I came across a user that keeps asking very low quality questions: most of them are down voted and close. Yet, this only happens when the users asks questions for a specific tag. For other tags, it seems like he/she makes a nice contribution to SO. It's just this specific topic/tag that the user refuses to learn and improve his/her questions. What can be done? It's annoying to keep getting these low-effort low-quality questions...   EDIT: I understand that the exact parameters of the banning mechanism are not published for good reasons. I'm not after the secret ingredients, and I believe the system works fine in general.    My question is regarding a particular user that on some topics (tags) exhibits "ban-worthy" behavior (at least to my understanding) while for others he/she is a respectable member of SO community.    Can a user be partly banned? Can this user be discouraged from participating in certain tags? Or better still, is there an effective way of helping this user improve his/her behavior and learn more before he asks for all tags?   Update: After a short period of peaceful quietness, this phenomenon repeats itself. Any new ideas?

If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?


Once I purchase an android app on the appstore, can I download it again and again in future (say I change devices or factory reset my phone)?

On the iPod Touch/iPhone, since it is tied to your iTunes account, I am quite sure you can have your bought apps on multiple devices you own (can't test though, iPod Touch was stolen).  However, now I have the Motorola Droid, and am waiting for a tablet, and am considering getting a Nook and rooting it to run my own apps.  Question is, if you buy an app on the marketplace, how is the security done:   Is it tied to your Gmail account so you can share it between devices you own? Is it tied to the device? (Don't break/replace your phone!) As long as it's installed, you're OK? (If you uninstall, or wipe your device, it's gone).   I assume 3 is highly unlikely, though a possibility, so leaving it here as a potential answer to my question.


I got it once but I reset and I forgot how to get it.

I've finished the game, got all the items except one. This is the one to the right of the green shark fin. What and where is it?


Which sentence is correct? “Why did you go and told mom about us?” “Why did you go and tell mom about us?”  I know that after “did”, the verb has to come as “simple form”, but when the sentence is long and follows with “and”, what happens to the second verb (after and) ? Does it have to come as “past tense” or “present tense”?

What is the proper way to combine past tense of do (did) with multiple bare infinitives in a question:   Did you go to vacation or stay at home? Did you go to vacation or stayed at home? Did you go to vacation or did you stay at home?   The last one is always correct, but I assume shorter form is more desirable, especially if more than two verbs are involved: Did you go to vacation, stay/stayed at home, go/went to work, or do/did something forth?  Also, if the second form is not correct, could it be transformed to Did you go to vacation or you stayed at home? I assume that this form has a little bit different meaning, because the emphasis is on vacation, and staying at home is just mentioned as one of the alternatives. Basically, this form can be answered with Yes or No, while the aforementioned three ones cannot (I offered two equally probable alternatives in the question). Does my reasoning on this make sense?  I am not a native English speaker and I caught myself using the second form occasionally (although it seems to clearly break the rule auxiliary verb + bare infinitive).


After subdivision surface modifier applied tris are quad anyway. Is there something makes sense?

I've read many times that triangles should be avoided in meshes, too give one reference: "Introducing Character Animation with Blender by Tony Mullen" says that equilateral triangles work fine as long you don't deform them.  It seems to be common in game development that the models are triangulated.   What issues are introduced by using triangles? Does the same apply for n-gons?


Is there a good tool/program that allows me to clone a system drive to another, smaller hard drive?  I've bought a new 64GB SSD drive and would like to move my current Windows 7 Professional 64-bit installation to that new drive. My current drive is a 200GB SATA drive with one partition only. Of course there's enough free space to shrink my current partition to less than 64GB.

I have a hard drive which is 153 GB with 116 GB free space. I would like to clone this drive to a hard drive which is a 149 GB big (this is the largest hard drive I have... It would be typical that my largest drive is only 4 GB to small).   Is there any way to do this (preferably with free or open source programs)? I am running Windows XP.


I have 2 problems.    1) I want to move the logo image and box to the center. I don't know why it doesn't work...  I think I've used everything including align, but it doesn't move. I solved the menus with a flex.  2) I want the borderline of menus and box to be the same size. The overlapping parts have different sizes of lines.  Thank you reading.

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I have a data set of paired measurements $(x_1,y_1),(x_2,y_2),...,(x_n,y_n)$. I need to fit a linear regression line $y=ax+b$ to this data. Therefore, I have to estimate the parameters $a$ and $b$.  How can I then calculate the confidence interval for these estimated parameters?  I referred to the wiki article which says :       Normal assumption      Under the first assumption above, that of the normality of the error   terms, the estimator of the slope coefficient will itself be normally   distributed with mean $\beta$ and variance $\sigma^2/\sum(x_i-\bar > x)^2$.   I didn't get how this formula was derived.

Let's have some linear model, for example just simple ANOVA:  # data generation set.seed(1.234)                       Ng <- c(41, 37, 42)                     data <- rnorm(sum(Ng), mean = rep(c(-1, 0, 1), Ng), sd = 1)       fact <- as.factor(rep(LETTERS[1:3], Ng))   m1 = lm(data ~ 0 + fact) summary(m1)   Result is as follows:  Call: lm(formula = data ~ 0 + fact)  Residuals:      Min       1Q   Median       3Q      Max  -2.30047 -0.60414 -0.04078  0.54316  2.25323   Coefficients:       Estimate Std. Error t value Pr(>|t|)     factA  -0.9142     0.1388  -6.588 1.34e-09 *** factB   0.1484     0.1461   1.016    0.312     factC   1.0990     0.1371   8.015 9.25e-13 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 0.8886 on 117 degrees of freedom Multiple R-squared: 0.4816,     Adjusted R-squared: 0.4683  F-statistic: 36.23 on 3 and 117 DF,  p-value: < 2.2e-16    Now I try two different methods to estimate confidence interval of these parameters  c = coef(summary(m1))  # 1st method: CI limits from SE, assuming normal distribution cbind(low = c[,1] - qnorm(p = 0.975) * c[,2],      high = c[,1] + qnorm(p = 0.975) * c[,2])  # 2nd method confint(m1)   Questions:   What is the distribution of estimated linear regression coefficients? Normal or $t$? Why do both methods yield different results? Assuming normal distribution and correct SE, I'd expect both methods to have the same result.   Thank you very much!  data ~ 0 + fact  EDIT after an answer:  The answer is exact, this will give exactly the same result as confint(m1)!  # 3rd method cbind(low = c[,1] - qt(p = 0.975, df = sum(Ng) - 3) * c[,2],      high = c[,1] + qt(p = 0.975, df = sum(Ng) - 3) * c[,2])


I'm trying to make an action on Automator that recursively batch  processes PNG images using bash shell script with pngquant  I have done this on terminal and got no problem, but now I want to make a finder action using Automator.  This is the shell script code (receives a directory input):  directory="$1" cd $directory find . -name '*.png' -exec pngquant --ext .png --force 256 {} \;   I'm having trouble with pngquant as it says:   pngquant: command not found

I have just compiled my own copy of ffmpeg on my system and it's located in the following path:  /opt/local/bin/ffmpeg   When I run the following command in Terminal.app, it runs smooth:  ffmpeg -i /Users/Amit/Documents/input.avi -c:v copy -c:a aac -b:a 384k -strict -2 /Users/Amit/Documents/output.m4v   However, a similar command run as a shell-script in an Automator service fails:  for f in "$@" do     ffmpeg -i "$f" -c:v copy -c:a aac -b:a 384k -strict -2 "${f%.*}.m4v" done   Up until now, I had a pre-compiled build of ffmpeg on my system located at:  /Applications/Scriptlets/   And my Automator shell-script had the full path (/Applications/Scriptlets/ffmpeg) instead of just ffmpeg; and it worked fine. However, today I decided to compile a fresh copy of ffmpeg using MacPorts and removed the earlier version from my Applications/Scriptlets folder. Now, this ffmpeg works fine in Terminal but gives an error whenever I try running it from a shell-script inside of an Automator workflow. Am I doing something wrong here? Please help!


I'am right now on my Ubuntu 14.04. I guess and I have a file on my Windows disks (I have three disks) and when I Click on one of them I have this message  Error mounting /dev/sda2 at /media/ubuntu/5208BE9708BE7995: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=999,gid=999,dmask=0077,fmask=0177" "/dev/sda2" "/media/ubuntu/5208BE9708BE7995"' exited with non-zero exit status 14: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. Failed to mount '/dev/sda2': Operation not permitted The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.   As I said it's not dual booting with my Windows 10 but it's LiveCD and i am running from my USB

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


So my question is this: $$V=\frac{4}{3}\pi r^3$$  And,  $$\frac{dV}{dr}=4\pi r^2=SA$$ Is this a coincidence or are there some mathematical hoodoos that I'm unaware of?  P.S. are there any more tags that I should use?

When differentiated with respect to $r$, the derivative of $\pi r^2$ is $2 \pi r$, which is the circumference of a circle.  Similarly, when the formula for a sphere's volume $\frac{4}{3} \pi r^3$ is differentiated with respect to $r$, we get $4 \pi r^2$.  Is this just a coincidence, or is there some deep explanation for why we should expect this?


I had the game but got nervous about traveling to catch Pokemon because of other people knowing where I am. I will get the game again but I want to know if this is true or not first.  Can Pokemon Go give your location to complete strangers?

Are other players able to see you on their map in Pokemon Go? I am concerned that if I use the game, stalkers and other such people would be able to find me. I have searched for an answer for this question on other forums, but have yet to find the answer.


I am using simple PHP mail function to send mail. Here is my code:  sendEmail('xyz@gmail.com', 'test subject', 'test body', 'xyz name', 'abc@gmail.com', 'HTML');  function sendEmail($to, $subject, $body, $fromName, $from, $format = '') {     $headers = '';      if($format=='HTML')     {         $headers .= "Content-type: text/html; charset=iso-8859-1\n";     }      $headers .= "From: $fromName <$from>" . "\n";      $success = mail($to, $subject, $body, $headers, '-f no-reply@xyz.com');     return $success;  }   My problem is this when i send more than one (like 10) mail then some mail goes into spam and some in inbox. If script is wrong then all mail should go into spam or if right then all mail into inbox.  Why some mail goes into spam and some in inbox?  while subject, body, message and email(to) is same.

I have been trying to get PEAR::mail to successfully deliver emails to hotmail users without being flagged as SPAM and ending up in the junk folder, i have no problems with yahoo/gmail only with hotmail.  google suggested that this is a common problem with hotmail and that possible causes can include   incorrect reverse DNS for main IP of the server lack of SenderId/SPF records  being blacklisted   having checked all of the above i can only think of one other reason - incorrectly formatted headers ?  to test this theory i set up outlook to send email via the same address that PEAR::mail uses and sent a quick test - it delivered straight to my inbox  so i compared the headers from the email sent from PEAR::mail against the headers sent by Outlook and there are only a few differences - i have only listed the differences to save space (and peoples eyes)  PEAR::mail headers (not in outlook headers)  X-PHP-Script: www.example.com/register.php for [users ip address]   Outlook headers (not in PEAR::mail headers)  X-Mailer: Microsoft Office Outlook 11 Thread-Index: Ack6CWSQlgV8s6+6SWyifka2NNpB7g== X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350   the only other differences that i can see are   the order of the From: and To: headers are reversed  and in the Received: section of the headers   Outlook  Received: from myhomehostname.com ([ip address] helo=simber)  by mywebhostname.com with local (Exim 4.67)   PEAR::mail  Received: from apache by mywebhostname.com with local (Exim 4.67)   could these small differences in the headers be the cause or am i looking in the wrong place ? i knew this might be problematic hence why i chose to use the PEAR::mail class rather than rolling my own but now i really have no idea where to go with this, any help would be greatly appreciated.  Update: as per changelog's suggestion i have tried adding the MS headers to the PEAR::mail class and i have tried replacing PEAR::mail with PHPMailer (with & without the extra headers) - they all end up in the junk folder.  I am starting to believe that it may not be the headers afterall.  Update 2: i should have mentioned that the emails are just a registration confirmation to validate the email address the user signed up with - no mailshots etc so our volume is extremely low.   I have considered warning users who provide a @hotmail/live email address to add us to their address book or check their junk folder - but this just seems unprofessional to me - it may be that i have to resort to this.  As for becoming Sender Score Certified - its very unlikely that i can justify the cost of this when considering the low volume and purpose of these emails.


I have just formatted my hp envy laptop with windows 8.1 and i tried to install Ubuntu but failed as it is not detecting OS so that it can be installed alongside. I have tried all your support of legacy mode and secure boot on off option but it did not work, i need Ubuntu plzz help, what to do??

Whenever I startup from the LinuxLive USB, and try to install Ubuntu 12.04, it only gives me two options instead of the usual 3 or 4. My options are "Replace Windows 7 with Ubuntu" and "Something Else". Whenever I go into "Something else", it looks extremely confusing. How do I install it side-by-side while using the "Something else" section? These are my partitions.   /dev/sda /dev/sda1 ntfs (104Mb, System Required Partition) /dev/sda2 ntfs (1000097Mb, Windows 7 Partition)   Or should I try reinstalling my installer on a CD rather than USB and maybe then it will have the "Install alongside" function?


Found this last night on my pillow.   Is this a bed bug?  I put it on a papertowel to take the pic.  Its about 3mm in length. I tried to zoom in the best that I could.

This bug was found on a couch in . The couch, and the two beds in the room show no signs of other bugs. Is this a bed bug that I should worry about or something harmless? It was slightly larger than a common tick.


I have been given some utility plant maps for a project my company is working on but they don't come with a projection listed (they are in PDF format, but I will strip them down, make them transparent, probably change to png or tiff.). I'd like to add them as a raster layer in QGIS 3.4 for reference and planning, but I am running into some problems.  I have tried using the georeferencer and cannot get any of the methods to work without grossly distorting the maps, or not giving me accurate enough results.  What I would like to do is: 1. Find out what projection these maps are in. 2. Set my project crs to the same. 3. Import the rasters (undistorted). 4. Set my project CRS back to what I am typically using.  Is there a good method for doing this? Because of the source of these files, I am presuming that they are in an actual projection, however, they may have been intentionally skewed.  Project CRS is EPSG:104199  Sample map to import:  EDIT: Added more images.  Linear Input  Linear Output  Polynomial 3 Input  Polynomial 3 output

I have a Shapefile but its coordinate system is Unknown, and there is no *.prj file.   How can I identify it now?


Blinkmoth Urn has an ability that only works if it is untapped at the start of a player's main phase. It has no activated abilities.  Can I, on my turn or any other turn, tap the artifact just to tap it, so it won't become untapped until just before my main phase? Is it legal to tap a permanent even if you are not paying a cost nor resolving a tap effect?  (If possible, a citation from the rules would be helpful, as the answer affects a coworker's main Commander deck.)

So a buddy and I were playing a game of Magic that turned out to be a really quick game because he got  out on the battlefield early. He was tapping it without attacking because of its obviously awesome ability but I don't know if you can tap a creature for its Inspired (untap-triggered) ability without attacking for it to then be tapped. Are you allowed to tap a creature whenever you want?


My question is -     Let, $f:[a,b]\to\Bbb{R}$ be a continuous function. Define   $g:[a,b]\to\Bbb{R}$ by $$ g(x)= \begin{cases} f(a), & \text{when}\quad  x=a\\ \operatorname{sup}_{(a,x]} f, & \text{otherwise} \end{cases} $$   Prove that $g$ is continuous on $[a,b]$.   I am able to prove the continuity of $g$ at $a$ in the following manner- By continuity of $f$ at $a$, we get - for any $\varepsilon>0\exists\ \delta>0$such that $f(a)-\varepsilon<f(x)<f(a)+\varepsilon\ \forall x\in(a,a +\delta)$. Thus for any $x\in(a,a +\delta)$, we have $f(a)-\varepsilon<\operatorname{sup}_{(a,x]} f<f(a)+\varepsilon\implies|g(x)-g(a)|<\varepsilon\ \forall x\in(a,a +\delta)$, since $f(a)=g(a)$, done.  Now, I want to work with the reamining $(a,b]$. So, I take a point $x_0\in(a,b]$ and $f$ is continuous at $x_0$. Choose $\varepsilon>0$. Then for this $\varepsilon>0,\exists\delta>0$ such that $f(x_0)-\varepsilon<f(x)<f(x_0)+\varepsilon\ \forall x\in(x_0 -\delta,x_0 -\delta)$. My claim is - $g(x_0)-\varepsilon<g(x)<g(x_0)+\varepsilon\ \forall x\in(x_0 -\delta,x_0 -\delta)$ or equivalently $\operatorname{sup}_{(a,x_0]} f-\varepsilon<\operatorname{sup}_{(a,x]} f<\operatorname{sup}_{(a,x_0]} f+\varepsilon\ \forall x\in(x_0 -\delta,x_0 -\delta)$. But I can't prove it rigorously. Can anybody complete my proof? Thanks for assistance in advance.

$f(x)$ is continuous on $[a,b]$. Now we define a new function $M(t)$, for every $t\in[a,b]$   $$M(t) = \sup_{a \leq x \leq t} f(x).$$  Prove formally that $M(t)$ is continuous on $[a,b]$. (sup = supremum)   $M(t)$ is monotonically increasing function, but I don't see how to continue from here.   Also I would like to know what are the standard strategy for proving a function is continuous on a given interval (not a point) except showing its a sum/product/composition of another continuous functions.


A user has recently been going through several tag-wikis on Stack Overflow and copy and pasting from Wikipedia into the excerpt and tag-wiki.  I flagged one of his posts and asked a mod to send him a message to  regarding the proper way to attribute Wikipedia.  He is now attributing Wikipedia properly in the main body of the tag-wiki, but failing to do so on the excerpt. According to badp's answer, excerpts can't contain links and a plain text link to Wikipedia might be considered unncessary filler.  Is there anything that should/can be done about this? The edits are still being approved, so should the excerpts be edited to add the Wikipedia links in plain text, should they be cleared until someone can properly edit them or just leave it alone and hope someone comes along to improve them? (Note that most (if not all) of the tag wikis are being created by this user).  Since someone else has already mentioned this user in another question, I think it is okay to mention that I'm talking about .

Assuming that you could make a nice tag-wiki simply by pasting and editing content from Wikipedia, is there any problem with doing something like that?  There are a lot of empty tag wikis that would be better off with default content from Wikipedia rather than an empty wall.  This would at least give people a starting point, I think it's easy to be intimated by the task of creating a new wiki page.  But there could be some social or legal issues with this.


I went through all the settings of the Minecraft, but did not find any settings for the debug list Well, maybe a couple of settings for the type of Profiler, etc. The essence does not change, a solid chunk of the data about coordinates, lighting, condition of the unit, all disappeared, this is as it should be in this version? Versions where tested-,1.13.2, 1.15.2 And by the way, hidden commands like displaying chunks or hitboxes don't work for me either I didn't know how to solve this problem. Result:Tell me how to solve this problem?

When I press F3 to see the debug screen in I use Minecraft 1.8.1, some information is missing.   Most notably, there are no X, Y, Z coordinates.     What happened to my debug overlay?


Here is my player code.  Rigidbody rb;  Vector3 currMovement; public float jumpSpeed = 10; public float moveSpeed = 10; public float rotSpeed = 180;  float distToGround;  public float smoothTimePos = 0.25f; float currPos; float targetPos; float posVel;  public float smoothTimeRot = 0.25f; float currRot; float targetRot; float rotVel;  void Start() {     rb = GetComponent<Rigidbody>();     distToGround = GetComponent<Collider>().bounds.extents.y; }  bool isGrounded() { return Physics.Raycast(transform.position, Vector3.down, distToGround + 0.1f); }  void Update() {     targetRot = Input.GetAxisRaw("Horizontal") * rotSpeed * Time.smoothDeltaTime;     targetPos = Input.GetAxisRaw("Vertical") * moveSpeed; }  void FixedUpdate() {     Move(); }  void Move() {     if (isGrounded())     {         if (Input.GetButtonDown("Jump"))             rb.velocity += Vector3.up * jumpSpeed;     }      // Rotation smoothing.     if (targetRot > 360)         targetRot -= 360;     if (targetRot < 0)         targetRot += 360;     currRot = Mathf.SmoothDampAngle(currRot, targetRot, ref rotVel, smoothTimeRot);      transform.eulerAngles += new Vector3(0, currRot, 0);      // Movement smoothing.     currPos = Mathf.SmoothDamp(currPos, targetPos, ref posVel, smoothTimePos);     currMovement = new Vector3(0, 0, currPos);     currMovement = transform.rotation * currMovement;      rb.position += currMovement * Time.smoothDeltaTime; }   I have a Rigidbody attached to my player. I think the problem is with my camera script. Here is my camera script.  public Rigidbody player; Quaternion targetLook; Vector3 targetMove, targetMoveRaycast, targetMoveUse; public float smoothLook = 8, smoothMove = 0.25f; public float distFromPlayer = 5, heightFromPlayer = 3; Vector3 moveVel;  void LateUpdate() {     CameraMove(); }  void CameraMove() {     targetMove = player.position + (player.rotation * new Vector3(0, heightFromPlayer, -distFromPlayer));      RaycastHit hit;     if (Physics.Raycast(player.position, targetMove - player.position, out hit, Vector3.Distance(player.position, transform.position)))     {         targetMoveRaycast = hit.point;         targetMoveUse = targetMoveRaycast;     }     else     {         targetMoveUse = targetMove;     }      transform.position = Vector3.SmoothDamp(transform.position, targetMoveUse, ref moveVel, smoothMove);      targetLook = Quaternion.LookRotation(player.position - transform.position);     transform.rotation = Quaternion.Slerp(transform.rotation, targetLook, smoothLook * Time.smoothDeltaTime); }   The player is not an parent of my camera. When I parent the player to my camera the shake stops. But I want a custom smooth camera movement with my custom scirpt, so I can't make the player a parent of the camera.

Here is my player code.  Rigidbody rb;  Vector3 currMovement; public float jumpSpeed = 10; public float moveSpeed = 10; public float rotSpeed = 180;  float distToGround;  public float posSmoothTime = 0.5f; float currPos; float targetPos; float posVel;  public float rotSmoothTime = 0.5f; float currRot; float targetRot; float rotVel;  void Start() {     rb = GetComponent<Rigidbody>();     distToGround = GetComponent<Collider>().bounds.extents.y; }  bool isGrounded() { return Physics.Raycast(transform.position, Vector3.down, distToGround + 0.1f); }  void Update() {     Move(); }  void Move() {     // Rotation smoothing.     targetRot = Input.GetAxisRaw("Horizontal") * rotSpeed * Time.smoothDeltaTime;      if (targetRot > 360)         targetRot -= 360;     if (targetRot < 0)         targetRot += 360;     currRot = Mathf.SmoothDampAngle(currRot, targetRot, ref rotVel, rotSmoothTime * Time.smoothDeltaTime);      transform.eulerAngles += new Vector3(0, currRot, 0);      // Movement smoothing.     targetPos = Input.GetAxisRaw("Vertical") * moveSpeed;      currPos = Mathf.SmoothDamp(currPos, targetPos, ref posVel, posSmoothTime * Time.smoothDeltaTime);     currMovement = new Vector3(0, 0, currPos);     currMovement = transform.rotation * currMovement;      if (isGrounded())     {         if (Input.GetButtonDown("Jump"))             rb.velocity += Vector3.up * jumpSpeed;     }      rb.position += currMovement * Time.smoothDeltaTime; }   I have a Rigidbody attached to my player. I think the problem is with my camera script. Here is my camera script.  public Transform player; Quaternion targetLook; Vector3 targetMove; public float smoothLook = 0.5f; public float smoothMove = 0.5f; public float distFromPlayer = 5, heightFromPlayer = 3; Vector3 moveVel;  void LateUpdate() {     CameraMove(); }  void CameraMove() {     targetMove = player.position + (player.rotation * new Vector3(0, heightFromPlayer, -distFromPlayer));     transform.position = Vector3.SmoothDamp(transform.position, targetMove, ref moveVel, smoothMove);      targetLook = Quaternion.LookRotation(player.position - transform.position);     transform.rotation = Quaternion.Slerp(transform.rotation, targetLook, smoothLook); }   }  The player is not an parent of my camera. When I parent the player to my camera the shake stops. But I want a custom smooth camera movement with my custom scirpt, so I can't make the player a parent of the camera.


I need to make my input field excepts 16 digits, and 20 chars. The digits are 1-9. And chars are only  ().   So, braces and dots. I can make those braces and dots into my regex to work.  $('#telephone').on('keypress', function (event) {     var regex = new RegExp("^[0-9]+$");      var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);     if (!regex.test(key)) {       event.preventDefault();       return false;     }   });   For example I tried:  var regex = /^[().]{20}[0-9]{16}$/;   And so on, but I guess I am missing a bigger picture. Thank you for your help.  The enterd data should look something like this:  33363748574635274()()....()()()..   And so on. No matter where is dot placed and where is brace placed.

I'm trying to put together a comprehensive regex to validate phone numbers. Ideally it would handle international formats, but it must handle US formats, including the following:   1-234-567-8901 1-234-567-8901 x1234 1-234-567-8901 ext1234 1 (234) 567-8901 1.234.567.8901 1/234/567/8901 12345678901   I'll answer with my current attempt, but I'm hoping somebody has something better and/or more elegant.


I have a logo in Illustrator that I inherited, I'm just trying to put it into an InDesign file but for some foresaken reason the text always comes out pixelated. (See attached screenshot)  I've tried "create outlines" for the text, saving and importing in .pdf, .tiff, .svg, .eps, .ai - you name it but cannot for the life of me get the text to render smoothly.   The artboard is about 1000px x 1000px and it only needs to be about 2 inches big in the InDesign document.   Raster effect settings are 300dpi.  Any suggestions appreciated!

I'm trying to place an illustrator CC file with many artboards all into an Indesign CC file.  When I paste in the illustrations, the bounding boxes are giant.  When I place the file from file > Place, the quality of the illustrations is greatly diminished (looks very pixelated)  What is the proper way to move my file to indesign so I can place these illustrations in a book?   Thank you


Which one is correct and why?  "Good luck at your new job" or "Good luck with your new job"?

What sentence is more correct?      I wish you luck in your studies.   Or     I wish you luck at your studies.    Or the both variants can be used?


I downloaded Apache httpd-2.4.18.tar.gz file. But I don't know how to install that one?!

I have downloaded tar.gz files. But I don't know how to install it. How do I install this kind of file?


I tried the following but I get the errors at the end. In order to make sure that 4.8.2 was not interfering, I removed it.  Any suggestions would be great!  sudo add-apt-repository ppa:ubuntu-toolchain-r/test sudo apt-get update sudo apt-get install g++-4.9  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  g++-4.9 : Depends: gcc-4.9-base (= 4.9.2-0ubuntu1~14.04) but 4.9.2-10 is to be installed            Depends: gcc-4.9 (= 4.9.2-0ubuntu1~14.04) but it is not going to be installed            Depends: libstdc++-4.9-dev (= 4.9.2-0ubuntu1~14.04) but it is not going to be installed E: Unable to correct problems, you have held broken packages. idf@C55t-A:/etc/apt$   Edit 1  When I used aptitude, I get these warnings although it seems to work  perl: warning: Setting locale failed. perl: warning: Please check that your locale settings:         LANGUAGE = "en",         LC_ALL = (unset),         LANG = "en_US.UTF-8"     are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory

How do I install the latest version of gcc and g++?  I am using a variety of C++11 and C++1y features; which is why I need this.


A few days ago I was using my computer perfectly fine, but now it's acting up. I tried using some code to reset my proxy, but it seem to have done more than it needed to.  if [ $(id -u) -ne 0 ]; then   echo "This script must be run as root";   exit 1; fi  gsettings set org.gnome.system.proxy mode 'none' ;  grep PATH /etc/environment > lol.t; cat lol.t > /etc/environment;  printf "" > /etc/apt/apt.conf.d/95proxies;  rm -rf lol.t;   I can still log in and I can still see my wallpaper and cursor, but my panel and icons are all gone. I right click and try to use the keyboard to open a terminal but I get nothing. I'm on Xubuntu 16.04.5. I've tried using the live cd to reinstall, but that keeps saying  "The installer encountered an unrecoverable error. A desktop session will now be run so that you may investigate the problem or try installing again."  but when the session opens it crashes, the screen goes to tty1 and asks for Xubuntu login. After a while I keep getting blk_update_request I/0 and SQUASHFS errors

I tried running some code to reset my proxy:  if [ $(id -u) -ne 0 ]; then   echo "This script must be run as root";   exit 1; fi  gsettings set org.gnome.system.proxy mode 'none' ;  grep PATH /etc/environment > lol.t; cat lol.t > /etc/environment;  printf "" > /etc/apt/apt.conf.d/95proxies;  rm -rf lol.t;   and it messed with my desktop environment. I made prior post about this and another user said I had some of my home files owned by root. I took their advice and put the permissions back, using:  sudo chown -R user:user ~/   But even after that, my background is the only thing that loads after logging in. I'm using Xubuntu 16.04 with xfce desktop.


Good afternoon.  I'm doing research for a possible hard science fiction project and was looking up information on dark matter.  Wikipedia--hardly an authoritative source, I know--mentions that the evidence for dark matter stems from an observation where galaxies were rotating around each other faster than what should be possible given visually observable mass.  Has there been an experiment or anything to try to explain the faster-than-expected rotation via Special Relativity?  I mean, we're sitting inside of a gravity well looking at galaxies very far away, wouldn't the perception of time be different since we're sitting in a different gravitational field?  I'm absolutely not a physicist--just a layman asking a question to people who might have a better idea than me.  Thanks.

If time travels slower nearer gravity wells, why can't the galaxy rotation speeds being faster on the outer edges than the inner areas be explained by relativity? What necessitates dark matter?


Another way to put it is that I want to create a material that will do the cropping for me.  If I apply this shader to a cube in the middle of the shot, then my render will have a cube-shaped block of transparency in the middle of the shot, even if there are objects behind the cube.  Can anyone provide me a pointer on this? I'm new to nodes.  Thank you thank you!  EDIT: I'm using Cycles.  EDIT EDIT: Thank you for your answer, Denis. I realized today that there's one thing missing from the solution you provided. I also need the object to cast shadows and show up in reflections. I can't quite get my head around to make that happen. Any help out there?  EDIT EDIT EDIT: Figured it out!

I am rendering out some bubbles for use in a composite Photoshop image, so I need to render as a transparent png with the bubbles semi-transparent.  I tried setting render output to RGBA and checking the transparent option under film, but while the resulting png is transparent the bubbles keep the environment background colour.  The bubbles are definitely semi-transparent, because if I include a coloured object in the scene behind them, it is visible through the bubbles in the render, but I can't find a way to allow the semi transparent material to have any alpha transparency in my png render.


I'm sure we're all aware now that when we see a greyed-out button, it either means that 1) we cannot click it, or 2) its current state is off - or false.  In my application, I have a square, which acts as a button, next to a list item. This button, when clicked, will either mark the selected item as Important or Not Important. When you hover over this "button", a tooltip appears.  My question is, what should the tooltip say?  If the button is greyed out, should it say "Important" or "Not Important"?  A grey button indicates a not important item, while a blue one indicates important.

I have a quick question about buttons that toggle between two states. (Think Play/Pause, or Shuffle/Regular Play.) As the title says, should the toggle show it's current state or the state to which it will transition?  I think people are used to the Play/Pause convention. But the Shuffle/Regular play might be more confusing if you show the transition state instead of current. For example, the built-in music player on the Xbox 360 does it this way: when it's in shuffle mode, it shows the icon for direct play and vice versa and it always confuses me (am I in shuffle mode or straight play).  I see it this way: Play/Pause is more like action as in begin playing or pause playing. Yes behind the scenes it is a state transition but to the user, there is an action. Whereas Shuffle/Straight Play is an option and it's best to show the current state (and possibly have only one icon and change button to show that the option is enabled/disabled). Thoughts?


I found this proof in a StackExchange thread and found it pretty understandable and simple:  "The other answers give some sort of formula, like you were trying to do.  But, the simplest way to see that the set of all finite subsets of $\mathbb{N}$ is countable is probably the following.  If you can list out the elements of a set, with one coming first, then the next, and so on, then that shows the set is countable.  There is an easy pattern to see here.  Just start out with the least elements.  $$\emptyset, \{1\}, \{2\}, \{1, 2\}, \{3\}, \{1, 3\}, \{2, 3\}, \{1, 2, 3\}, \{4\}, \ldots$$  In other words, first comes $\{1\}$, then comes $\{2\}$.  Each time you introduce a new integer, $n$, list all the subsets of $[n] = \{1, 2, \ldots, n\}$ that contain $n$ (the ones that don't contain $n$ have already showed up).  Therefore, all subsets of $[n]$ show up in the first $2^{n}$ elements of this sequence."  I understand how it applies for finite subsets of N, but I cant really pinpoint of why it would not apply to a set of all subsets of N. We could continue this scheme for ever, couldnt we?  I assume that I think in a wrong way about infinity but I am not quite sure. Any help is greatly appreciated!

Show that the set of all finite subsets of $\mathbb{N}$ is countable.   I'm not sure how to do this problem. I keep trying to think of an explicit formula for 1-1 correspondence like adding all the elements in each subset and sending that sum to itself in the natural numbers, but that wouldn't be 1-1 because, for example, the set {1,2,3} would send to 6 and so would the set {2,4}.  Multiplying all the elements in each subset and sending that product to itself in the natural numbers wouldn't work either since, for example, {2,3} would send to 5 and so would the set {1,5}. Any ideas?


Consider the following sentences:  I steer my vehicle as close as possible to the right.  OR  I steer my vehicle as closely as possible to the right.  The first sentence is my version (I am not a native speaker), the second version is the corrected version form an English native speaker. I understand why the correction was made, since the corrector asked herself "How do I want to steer the vehicle? As closely as possible". So "closely" is the adverb to "steer", which makes total sense. However, I still feel like the first version sounds more natural. What if I ask "Where do I want to steer the vehicle to? As close as possible to the right."? Does that make a difference, or am I just kidding myself here?

I just came across something I'd written a while ago that contained the phrase "follows close behind", and my first thought was that it was incorrect and should be "follows closely behind", i.e. to use an adverb describing how something is following.  The  for the two phrases seems to disagree with this instinct, though, with only slight differences between BE and AE, and the shorter phrase must've made it past my inner editor back when I first wrote it... maybe because "close" can also be used as an adverb?  So can both be used interchangeably? Is there a grammatical reason one should be considered "more correct" than the other, or is it just a case of one particular usage of a phrase having become more commonplace for some reason or other?


The spell Shape Water lets a caster animate some water.  While the effect is limited to 'simple shapes', lasts an hour, and acts according to your direction, nearly nothing else about the effect is specified.  I want to know how the animated water option of Shape Water works and what it is capable of, for example:  Anna the Wizard casts Shape Water animating the water in a 5' hole excavated via Mold Earth.  She forms the water into the crude shape of a miniature horse, and attempts to put a miniature saddle on it.  What happens?  Her weasel familiar attempts to mount the water-horse.  What happens?  She casts Find Familiar and changes her weasel familiar into a fish, which attempts to swim in the 'horse'.  What happens?  The 'horse' gallops away.  How fast can it go?  Does the fish go with it?  Anna casts Shape Water a second time on a second hole, this time animating the water into a 20' radius hollow sphere a quarter-inch thick (the volume ).  What happens? Anna climbs to the top of a 20' tall A-frame ladder and mentally directs the sphere to roll over her so that she is at the center.  What happens? Her buddy Bartholemew wants to throw an overripe tomato at her from outside of the sphere (Don't worry, Anna prepared featherfall today).  Does she have cover?  If so how much?  If it is total cover, does that stop Bob from trying to throw the tomato?  Anna then tells the sphere to go knock on the door of Cardamon the Cultist, who lives next door to her in a town 2.5 miles away, and then to find and roll over the unprotected flames she expects Cardamon's kids will have left somewhere in their back yard, and then to track down a copy of the Book of Exalted Deeds and bring it back to her.  How much of this can the sphere do?  Anna dismisses her familiar and then the galloping water-horse before casting Shape Water yet another time, on a third hole, this time forming the water into a comically large mallet.  She has the mallet spin up into the air and then fall down on practice dummy.  Does the practice dummy take any damage?  Is it moved?  Is it wet?  Later, she has the mallet fly around bonking some enemies on the head.  What happens?  In general, this spell (and to a lesser extent Control Flames) is often extremely problematic in games I run or play in, essentially requiring the GM to come up with mountains of rulings as to how the nearly endless uses of animated water constructs work, and what they can and can't do.  The spell clearly lets you make stuff with the water and have it do stuff, but it feels like there must be a whole bunch of rules somewhere I'm missing or something.

I have been having a discussion regarding the Shape Water cantrip from the Elemental Evil Player's Companion. A friend and I are trying to come to an accurate view of how this spell actually functions.   Some example questions:   Must the targeted water be within a 5 foot cube area, or does it need to be of a volume not exceeding 125 cubic feet? If you shape water that is within a 5 foot cube, can the final shape you animate it to extend outside the cube? Can you cause the shaping to affect ice and snow, or only liquid water? Would you be able to carry a globe of water alongside you over distances?   Really, there are two parts:    What can be targeted by the spell? What are the limitations on the 'shape and animate' portion of the spell?   The answer I am looking for, if possible, would use the language of the spell, possibly with precedent from other game text, to clearly define the limitations of this cantrip.


I know that refraction is caused due to change in speed of light but why does it bends? I also know that during refraction frequency is constant and wavelength is decreased since speed slows down. But please tell me why it bends ,it should have slowed down and passed straight?

Why does  happen? In high school textbooks, it is stated that it happens because the speed that electromagnetic waves propagate in the media change. But why cant they continue propagating in the same direction with a different speed?


Can anyone explain the prime difference between doing something like:  <car>    <color>        Blue    </color> </car>  VERSUS  <car color="blue" />

At work we are being asked to create XML files to pass data to another offline application that will then create a second XML file to pass back in order to update some of our data. During the process we have been discussing with the team of the other application about the structure of the XML file.   The sample I came up with is essentially something like:  <INVENTORY>    <ITEM serialNumber="something" location="something" barcode="something">       <TYPE modelNumber="something" vendor="something"/>     </ITEM> </INVENTORY>   The other team said that this was not industry standard and that attributes should only be used for meta data. They suggested:  <INVENTORY>    <ITEM>       <SERIALNUMBER>something</SERIALNUMBER>       <LOCATION>something</LOCATION>       <BARCODE>something</BARCODE>       <TYPE>          <MODELNUMBER>something</MODELNUMBER>          <VENDOR>something</VENDOR>       </TYPE>    </ITEM> </INVENTORY>   The reason I suggested the first is that the size of the file created is much smaller. There will be roughly 80000 items that will be in the file during transfer. Their suggestion in reality turns out to be three times larger than the one I suggested. I searched for the mysterious "Industry Standard" that was mentioned, but the closest I could find was that XML attributes should only be used for meta data, but said the debate was about what was actually meta data.  After the long winded explanation (sorry) how do you determine what is meta data, and when designing the structure of an XML document how should you decide when to use an attribute or an element?


I have the following UTF-8 data in my database:  ããƒ€ãƒ³ãƒ’ãƒ«  In japanese:  ダンヒル  The field and the database are set to utf_8_general_ci. I can't figure out how to display the proper japanese characters in my html. Here's what I did so far with no success:  <?php mb_internal_encoding('UTF-8'); mb_http_output('UTF-8'); header('Content-Type: text/html; charset=UTF-8'); ?>   Also, in my html header, I set the charset to utf-8:  <meta charset="UTF-8">   Database connection is mysqli, set_charset is set to utf-8.  Note that using this , I managed to encode my string to the proper japense characters.  Any help, would be appreciated, thanks!

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