I have a weird problem on server after the attack. In the web folder I have the index.php with malicious content. When I try to delete, rename it or change its content it is re-created somehow.  I checked crontab and ps but I haven't found anything suspicious.  Also it is very interesting that if I change the owner of the file to root it is still re-creating without any problem.   Server system name and version: Debian GNU/Linux 8 (jessie)

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


The original problem was to prove that for any commutative ring R, there is a canonical (unique) ring homomorphism from Z to R. The problem would be simple, if R has $1_R$ and we can let the homomorphism map $\phi$ sends $0$ to $0_R$ and $1$ to $1_R$. But if R doesn't have an identity, and $\phi(Z)$ forms a subring of $R$ with unity $\phi(1)$, then the Rng $R$ has a subring with unity. If ring without unity can only have a trivial subring with unity, $\phi$ must be the trivial map, and the proof would be complete. But I'm not sure of this part. Any help would be appreciated!

A ring need not have a unit element, e.g. even numbers.      Can someone give me an example of a ring which doesn't have a unit element but it's subring does have a unit element.


I know that / stands for folder, but there is one thing I don't get.  Command to illustrate the problem:  mv ~/Documents/newfolder ./anothernamefolder   Why there is / here? What does it do? Why can't I type:  mv ~/Documents/newfolder . anothernamefolder

For example, I can do the following  touch a  or  touch ./a  Then when I do ls I can view both, so what exactly is the ./ for?


I would like to download 2010 census population,aging and housing information at blockgroup level.Such as Total population,age_5_9...,age_85_up,Household Count,Housing_units,SQML etc

I'm in a introduction course for ArcGIS and I'm just starting to work on my project. I'm trying to create a map showing the relationship between poverty and education. I also want to try and present other correlations like race, healthcare, access to services, environment.  My question is regarding the  for the Census Bureau. How do I get data for household income for each state? Should I use the FactFinder page? Are there other ways of obtaining this data?


I want to know if i can pass an argument with an alias command.  for example:  alias d="dmesg|grep -iw usb|tail -5"    Now d will print the last 5 lines. if i want to use d to print a different number of lines, i have to make change in the alias command declaration of d again.  Is there any way i can modify the declaration of alias command so that i don't have to retype the declaration to change the number of lines. Like incorporating passing the number of lines as an argument while declaring alias for d or is there some other method to solve this?

I have an executable that I use often:  /dir1/dir2/dir3/dir4/executable argv[1] argv[2] argv[3]   I know that I can set an alias for the executable:  alias myexecutable = '/dir1/dir2/dir3/dir4/executable'   and then call it  myexecutable argv[1] argv[2] argv[3]   However, I'd like to call it like this  myexecutable argv[1]   because the first argument is the only one that ever changes. The second and third one should always be passed as the same every time.


I can compile a Fortran code using gfortran -o $target *.o -lblas  But it does not compile with gfortran -lblas -o $target *.o  Why does it depend on the position of the -lblas flag? Is it the standard behavior? If not, how can I troubleshoot? The BLAS libraries are in a non-standard location and set in the LD_LIBRARY_PATH environment variables. Running gfortran v9.3.0 on Ubuntu 20.04.

Why does the order in which libraries are linked sometimes cause errors in GCC?


This is the first time trying to install ubuntu for me.  Basically I followed along this tutorial in YouTube:   I am not given the option to install Ubuntu alongside windows 10. However it does show up when I click on "something else". I don't know how to go from there though.  Here are some steps I've taken so far   created a system image on external usb to backup windows Shrink the Windows 10 partition to make space for Ubuntu (shrunk 50000mb as in video) installed ubuntu 16.04.1 onto usb installed Universal USB Installer booted into Ubuntu Linux Installation environment and began installing Ubuntu (did not finish installation)   How do I install along side Windows 10, I imagine it's with using "something else". I had windows 7 previously installed on this computer, and both 7 and windows 10 show up in "something else".

I'd like to see the full How-To on how to use manual partitioning during Ubuntu installation. The existing guides (at least those I found here) cover only automatic part and leave untouched the manual part (or extremely short and contain no pictures).  I'd like to cover such situations:     If your disk contains other systems:


How it is true that a group whose order is the product of two primes is a cyclic group?  Consider a group of order $6=2\times 3$. I know $O(\mathscr{S}_3)=6$ but $\mathscr{S}_3$ is not cyclic.  Is there some additional info about the result stated above?  Kindly provide the proof for it too.

I don't know about the Sylow Theorems.  But I have been wondering about a proof of the fact that a group or order $pq$ where $p$ and $q$ are distinct primes must be cyclic. I can't quite work out the details, but here is the general idea. I would like help with filling in details. I assume that it is already known that $G$ has subgroup(s) of order $p$ and subgroup(s) of order $q$.  If $G$ is a group of order $pq$ ($p\neq q$), then I know that $G$ has a subgroup $H$ of order $p$ and a subgroup $K$ of order $q$. Then $H\simeq \mathbb{Z}_p$ and $K\simeq \mathbb{Z}_q$.   But then $H\oplus K \simeq \mathbb{Z}_{pq}$, so I would think that $H\oplus K \simeq G$. I guess one could do an internal direct product instead of an external direct product, but I don't know that $H$ and $K$ are normal subgroups.  I am asking for help completing this argument.  Edit: I see from the comments below that I might need to assume that the smaller prime does not divide the larger prime minus $1$. Or maybe it is enough to assume that the primes are greater than or equal to $3$ (Still distinct).


My JS woks well when the city has one word:   cHIcaGO ==> Chicago   But when it's   san diego ==> San diego   How do I make it become San Diego?  function convert_case() {     document.profile_form.city.value =         document.profile_form.city.value.substr(0,1).toUpperCase() +          document.profile_form.city.value.substr(1).toLowerCase(); }

Is there a simple way to convert a string to Title Case? E.g. john smith becomes John Smith. I'm not looking for something complicated like , just (hopefully) some kind of one- or two-liner.


I tried to play around with $2^{2^{n + 1}} - 1$, such as splitting it to $2^{2^{n} \cdot 2} - 1$, but it didn't helped much. I am kind of stuck and don't know what to do next

This is just a curiosity. I have come across multiple proofs of the fact that there are infinitely many primes, some of them were quite trivial, but some others were really, really fancy. I'll show you what proofs I have and I'd like to know more because I think it's cool to see that something can be proved in so many different ways.  Proof 1 : Euclid's. If there are finitely many primes then $p_1 p_2 ... p_n + 1$ is coprime to all of these guys. This is the basic idea in most proofs : generate a number coprime to all previous primes.  Proof 2 : Consider the sequence $a_n = 2^{2^n} + 1$. We have that  $$ 2^{2^n}-1 = (2^{2^1} - 1) \prod_{m=1}^{n-1} (2^{2^m}+1), $$  so that for $m < n$, $(2^{2^m} + 1, 2^{2^n} + 1) \, | \, (2^{2^n}-1, 2^{2^n} +1) = 1$. Since we have an infinite sequence of numbers coprime in pairs, at least one prime number must divide each one of them and they are all distinct primes, thus giving an infinity of them.  Proof 3 : (Note : I particularly like this one.) Define a topology on $\mathbb Z$ in the following way : a set $\mathscr N$ of integers is said to be open if for every $n \in \mathscr N$ there is an arithmetic progression $\mathscr A$ such that $n \in \mathscr A \subseteq \mathscr N$. This can easily be proven to define a topology on $\mathbb Z$. Note that under this topology arithmetic progressions are open and closed. Supposing there are finitely many primes, notice that this means that the set $$ \mathscr U \,\,\,\, \overset{def}{=} \,\,\, \bigcup_{p} \,\, p \mathbb Z $$ should be open and closed, but by the fundamental theorem of arithmetic, its complement in $\mathbb Z$ is the set $\{ -1, 1 \}$, which is not open, thus giving a contradiction.   Proof 4 : Let $a,b$ be coprime integers and $c > 0$. There exists $x$ such that $(a+bx, c) = 1$. To see this, choose $x$ such that $a+bx \not\equiv 0 \, \mathrm{mod}$ $p_i$ for all primes $p_i$ dividing $c$. If $a \equiv 0 \, \mathrm{mod}$ $p_i$, since $a$ and $b$ are coprime, $b$ has an inverse mod $p_i$, call it $\overline{b}$. Choosing $x \equiv \overline{b} \, \mathrm{mod}$ $p_i$, you are done. If $a \not\equiv 0 \, \mathrm{mod}$ $p_i$, then choosing $x \equiv 0 \, \mathrm{mod}$ $p_i$ works fine. Find $x$ using the Chinese Remainder Theorem.   Now assuming there are finitely many primes, let $c$ be the product of all of them. Our construction generates an integer coprime to $c$, giving a contradiction to the fundamental theorem of arithmetic.  Proof 5 : Dirichlet's theorem on arithmetic progressions (just so that you not bring it up as an example...)  Do you have any other nice proofs?


Let $R$ be a ring with $1$ and $M$ a left $R-$module. The module $M$ is said to be uniserial if the poset of submodules of $M$ is a chain. Let $M$ be a  uniserial module and $\alpha,\beta\in End_R(M)$.      Why we have:  $\alpha\beta$ is injective if and only if both $\alpha$ and $\beta$ are injective.   Thanks in advance

Please help me to prove the following result:  Let   $R$  be  a ring with $1$ and $M$ a uniserial left $R-$module and $\alpha,\beta\in End_R(M)$.      $\alpha\beta$ is surjective if and only if both $\alpha$ and $\beta$ are surjective   This is what i wrote:  The implication  if both $\alpha$ and $\beta$ are surjective then $\alpha\beta$ is surjective is evident since the composition of two surjective functions is surjective:   Let $\alpha:M \to M$ and $\beta:M \to M$ be surjective functions.   We wish to show that $\alpha\circ \beta:M \to M$ is also surjective.  Now, we know that for every $c \in M$, there is a $b \in M$ such that $c = \alpha(b)$, by surjectivity of $\alpha$. And we know that for that same $b$, there exists an $a \in M$ such that $b=\beta(a)$, by surjectivity of $\beta$.  So what we have shown is that for every $c \in M$, there is an $a \in M$ such that $c=\alpha(\beta(a))=\alpha \circ \beta(a)$, i.e., $\alpha \circ \beta$ is surjective.  For the other inmplication let us suppose that $\alpha\beta$ is surjective. Let $a\in M$ by sujectivity of $\alpha\beta$ there exist $b\in M$ such that $\alpha\beta(b)=a$ hence there exist $c=\beta(b)\in M$ such that $\alpha(c)=a$ then $\alpha$ is surjective   But i am not able to prove that $\beta$ is also surjective. Please help me to do so. Thanks in advance.


Prove that a connected graph with n vertices has at least $ n-1 $ edges.   Prove by M.I: we know that deg(v) $\ge1$ for all vertices v, since the graph is connected. Then either deg(v)$\ge 2$ for all v, or there exists one vertex with degree 1. How do I actually show this desired result. Any help is appreciated.   Step 1: Let n=1, then there are 1-1=0 edges. True  Step 2: Show that a connected graph with n+1 vertices, it has n+1-1 edges. I need help on this part. Do I need to use the summation of degree (v)= 2 times the number of edges?

Show that every connected graph with $n$ vertices has at least $n − 1$ edges.  How can I prove this?  Conceptually, I understand that the following graph has 3 vertices, and two edges:  a-----b-----c  with $a$, $b$ and $c$ being vertices, and $\{a,b\}$, $\{b,c\}$ being edges.  Is there some way to prove this logically?  --UPDATE--  Does this look correct?  Any advice on how to improve this proof would be appreciated.  Thank you.


Ok so i have this kind of query  SELECT * FROM table WHERE column LIKE 'Blahblahblah Blah - Blah (Blah-Blah)'   (Yep, column values are 20-30 characters long) And it works in phpmyadmin and returns ~ 100 results. But whn i try it in PHP framework CI (CodeIgniter) It is not returning any values. My code looks like:  $sql = "SELECT * FROM table WHERE column LIKE '$val' ORDER BY column ASC"; $sql = $this->db->query($sql); return $sql->result();   So how do i get this to work?

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I'm trying to show combinatorially that  $$S(n+1, k) = \binom n0 S(0,k-1) + \binom n1 S(1,k-1) + \cdots + \binom nn S(n,k-1),$$ where $S(n,k)$ represents the Stirling number of the second kind. I've received the hint that I should first find a combinatorial argument to show that $$\binom {n+1}k = \binom 0{k-1} + \binom 1{k-1} + \cdots + \binom n{k-1},$$  but I can only find an algebraic proof using several iterations of $$\binom {n+1}k = \binom nk + \binom n{k-1}.$$ Could someone please point me in the direction for how I should be thinking about these problems?

has the identity $$S(n+1, k+1) = \sum_i {n \choose i} S(i, k)\;.$$ I can't seem to find a proof for this and was wondering what it entails. Is it a purely combinatoric argument, or an algebraic manipulation of the explicit formula $S(n, k) = \frac{1}{k!} \sum_{i=0}^k (-1)^i {k \choose i}(k-i)^n $ with the known recurrence formula $S(n+1, k+1) = S(n, k) + (k+1)S(n, k+1)? $


When a bucket attached to a string is whirled in a vertical circle , why it doesn't fall down when at the top most point because no "real" forces are acting on it in the upward direction and please explain from inertial frame of reference

A bucket is rotating in a uniform circular motion. When the bucket is at the topmost point in the loop, the water does not fall. At this point both the tension and gravitational force is acting on the water, then it should be pulled with an even greater force. Then why does the water not fall?  The same question can be asked about a motorcyclist performing a loop de loop. Why does he not fall on the topmost point when both gravity and normal reaction are acting downwards?


If only one then how Parent class constructor gets executed when sub class object is create    class Parent {  Parent()  {   System.out.println("Parent class construcor");  } } class Child extends Parent  {  Child()  {   System.out.println("Child class construcor");  }   }  class Test  {   public static void main(String a[])   {    Child obj = new Child();   }  }

I have a question about inheritance in Java.  I have two classes A and B , and class B, inherits from A:  public class A {      public A() {          System.out.println("Hi!");      } }   public class B extends A {      public B() {          System.out.println("Bye!");      }       public static void main(String[] args) {          B b = new B();      } }   When I run program B, the output is:  Hi! Bye!      Question : why the constructor of class A is invoked, when I create and object of class B ?    I know that B inherits everything from A - all instance or class variables, and all methods, and in this sense an object of B has all characteristics of A plus some other characteristics defined in B. However, I didn't know and didn't imagine that when I create an object of type B, the constructor of A is also invoked. So, writing this:  B b = new B();   creates Two objects - one of type B, and one of type A.  This is getting interesting,   can somebody explain why exactly this happens?


Rey stole his ship, and he was talking to Han. There didn't seem to be any other ships there.

Near the end in amongst the battle, Kylo Ren lands next to his ship that Rey stole. I understand that at a stretch (or through the will of the Force) Kylo found a TIE Fighter in the wreck he was in, but to my understanding those TIEs would not have had hyperdrives, so how did he travel that far without a carrier ship? I suppose I'm guessing/assuming that he travelled on his own (Solo if you will), and not with his Star Destroyer, as the Knights who travelled with him on his Star Destroyer were already at the destination. But if the Force willed him to find the TIE Fighter, why not a shuttle with a hyperdrive? It would be iconic enough to use in the film, surely.  How did Kylo Ren travel to another system in a civil war era TIE Fighter with no hyperdrive or carrier ship?


I am writing a LinkedList reverse method, in the main method, I am defining temp and calling reverse method (root contains the linked list)  Node temp=null; r=a.reverse(root,temp);  public Node reverse(Node node,Node temp){     if(node!=null){         Node n=new Node();         n.data=node.data;         n.next=temp;         temp=n;         node=node.next;         reverse(node,temp);     }     return temp;     }   My rote contains 10,20,30,40,50` while I print Node returned by reverse method, I get the output..     o/p--- 10

I have been working on a Java project for a class for a while now. It is an implementation of a linked list (here called AddressList, containing simple nodes called ListNode). The catch is that everything would have to be done with recursive algorithms. I was able to do everything fine sans one method: public AddressList reverse()      ListNode:    public class ListNode{   public String data;   public ListNode next; }   Right now my reverse function just calls a helper function that takes an argument to allow recursion.  public AddressList reverse(){   return new AddressList(this.reverse(this.head)); }   With my helper function having the signature of private ListNode reverse(ListNode current).  At the moment, I have it working iteratively using a stack, but this is not what the specification requires. I had found an algorithm in C that recursively reversed and converted it to Java code by hand, and it worked, but I had no understanding of it.  Edit: Nevermind, I figured it out in the meantime.  private AddressList reverse(ListNode current, AddressList reversedList){   if(current == null)        return reversedList;   reversedList.addToFront(current.getData());   return this.reverse(current.getNext(), reversedList); }   While I'm here, does anyone see any problems with this route?


In Illustrator how can I merge this roof vector to the background of the square?

I have this logo I am working on. I have 2 questions:  1) I have a white circle behind the 4. I'd like to use that circle as a clipping mask for the 4 so that the 4 fits perfectly within that white circle. How can I do this?  2) After that, if I wanted to paint the 5 areas in white (between blue and green) each a different color, how can I isolate those areas to paint?  Thanks!


If i'm using the google map api in a third party app I'm making, can I make use of the offline map function of Google Maps?

In newer Google Maps I can make area available offline.  Do other applications that rely on Google Maps (utilize Google Maps Android API) use offline maps?


Let $p$ and $x$ be two positive integers greater than 2. If it is given that the sum : $$1+x+x^2+x^3... x^{p -1}$$  is a prime, is it possible to prove or disprove that $p$ is prime? If so, what would this proof be?

Will be glad for a little hint: let x and n be positive integer such that $1+x+x^2+\dots+x^{n-1}$ is a prime number then show that n is prime


I am trying to do the same thing as this poster, but in BibTeX:  I cannot get BibLaTeX to work for me (see ), and it compiles very slowly anyway.  Does anyone know if it is possible to achieve this result in BibTeX?

How can I cite a range of papers, the output is a range of numbers, instead of a list of numbers? In other words, when I type  ... some dummy text here is due to me \cite{me1, me2, me3, me4} ...   I want the output to be     ... some dummy text here is due to me [3-6] ...   instead of     ... some dummy text here is due to me [3.4.5.6] ...   (I use LaTeX, and am currently using the amsart class and whatever it includes. But I am open to other suggestions.)


Im building a math testing program for class. A user enters a username, the number of problems, and the number of digits. The program spits out a problem and the user answers in a textfield on that page.   Is there a way to make a default page that loads different JPanels based on a button action? Additionaly, Can you store Jpanels in an arrayList and store the inputs?  ArrayList <JPanel> arrList = new ArrayList<>();  for(int i = 0; actionListener == true ; i++){      default_JFrame().add(arrList.get(i)); }   Are there any general best practices for Java Swing?

To put it simple, there's a simple java swing app that consists of JFrame with some components in it. One of the components is a JPanel that is meant to be replaced by another JPanel on user action.  So, what's the correct way of doing such a thing? I've tried  panel = new CustomJPanelWithComponentsOnIt(); parentFrameJPanelBelongsTo.pack();   but this won't work. What would you suggest?


I have a table with a clustered PK. No foreign keys reference it. When I drop it I expect it to be more or less instantaneous, but it is instead very slow.  My assumption was that we'd just be removing some metadata and not having a constraint or clustering for future updates and inserts.  What is actually happening internally to make this expensive?

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


I am not sure if this comment about a suggestion on stackoverflow should be written here, but I do think so.   I would recommend, if this is possible, when downvoting a question, to be mandatory for the downvoter, to write the reason why he/she downvoted. I think this should be much more helpful for the OP to understand better what he did wrong, in order to fix it, if he does not want to get more downvotes. Downvoting itself, does not help the OP much, nor the people that might have a similar programming problem.  Please write what do you think guys. I know that most of you will disagree with me, but I find that giving feedback when downvoting is more useful for all of us.

Note: If you're looking for a simple explanation as to why comments aren't required on downvotes, see .   I used to get "upset" (though that is too strong a term) when I got downvoted without comment. If my answer isn't good enough then I'd like to know why. Not only does it improve the answer for the OP but it improves my knowledge too.  Where the down-vote has been explained I've found it useful & it has improved my answer, or forced me to delete the answer if it was totally wrong.  So is there any way we can encourage people to leave a comment? Perhaps they don't lose rep if they explain their down-vote?  I must admit though that I haven't always explained my down-vote either so you could call me a hypocrite. I've also grown a thicker skin over the months of using SO (it seems to have come with the higher rep score ;-)), so I'm less bothered about this now.


Im using a 74ls08 and gate ic, and I cant drive a 6v relay by using the output of the 74ls08. In what way can I drive the relay?

I couldn't find a definitive answer.   What's more suitable to drive a 5v relay from a 3.3v MCU, a MOSFET or a BJT Transistor? NPN or PNP?   I will be using a Schottky SS34 as flyback diode. Relay consumes 75mA. I can use NPN transistor MMBT3904LT1G or N-Channel MOSFET BSS138 for turning on the relay, emmiter/source to ground, would that be ok?


I installed Ubuntu 12.04LTS without turning off Fast Startup in Windows 8.1 as I was unaware that this needed to be done. I've installed Ubuntu many times before, but this was my first time with windows 8.1, and unfortunately I didn't look up anything before I did it. I resized the partition and installed Ubuntu successfully and upon reboot, it went directly to Ubuntu without grub showing up. Is there anything I can do as the windows partition is my primary one and there is software that I need access to on it.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


I am using the code  \noindent where $rc$ is density ($\rho$) multiplied by heat capacity ($C_p$), $k$ is thermal conductivity, $h$ is the heat transfer coefficient, $ambT$ is the ambient temperature, $iniT$ is the initial copper temperature, and $q$ is a heat source internally supplied to the sample ($\dot{q}$). \\  \noindent Then, the differential equation with boundary and initial conditions is defined:   in the online LaTeX site sharelatex.com. While it looks the way I want, it gives the error Underfill \hbox (badness 10000) in paragraph and I'm not sure how to fix it. I have seen other similar questions, but none of the solutions given seemed to work in my situation. If anyone could help me do it without the error, that'd be great.

Here is the thing, I have always used a blank space between paragraphs in order to tell latex that there is a new paragraph. But there is someone I work with very often that keeps using \\ to break a line after a paragraph...  This is really annoying so I wanted to know if there is a real advantage of using \\ over just leaving a space.  Note that I am not referring to the paragraph environment, but to the simple term paragraph.


I am a great fan of eggs and have consumed many eggs a day since I was young.  I had not even the slightest worry about my blood cholesterol level until an old man told me yesterday about the detrimental effects that over eating eggs might have on my health.   Does eating three to five whole eggs each day increase the level of blood cholesterol?

Last couple of day I have been having 3 whole eggs scrambled with around 2 tea spoon soybean oil in breakfast. Some friends of mine told me having 3 whole eggs is harmful for my health. I understand that it may increase my cholesterol. But in my opinion, eggs are fulled with protein and other important nutrients ( and easy to cook :P ). Do eggs raise cholesterol levels?


I have a cadastral database which requires multi-user editing/updating on daily basis.   I am trying to migrate from Esri enterprise geodatabase to PostGIS/PostgreSQL. I am not sure PostGIS offers versioning option similar to the Esri versioning.

Not that I am in any immediate need of a right answer here, but I've lately seen some efforts to introduce the concept of "(distributed) version control systems" for geographic data. Some examples (that I know of) are the three whitepapers from OpenGeo (,  & ) and the " (geosyncronization)" project by Norwegian GIS Software vendors and the Norwegian Mapping Agency. I've also found , which mentions GeoGit (by OpenGeo), and  about version control in ArcGIS.  Being a developer I know (at least enough to be able to use them) how version control systems for source code (like SVN and Git) works, and my background in geomatics tells me that there are some unique challenges with geographical data that makes the approach not completely similar to the way source code (which is basically text) are handled.  What are the challenges when dealing with (d)VCS'es for geographical data, how would you solve them, do we need them and are there other attempts to solve these issues than the ones I have mentioned?  I know that the OpenGeo whitepapers will answer some of my questions, but what I'm really is after is a more "pedagogical" answer, in the style of "tell me like I'm a 10-year-old", so that I can refer people to a great explanation of the challenges and solutions that geographical data brings to the mix.  I hope that someone with some insight will take time to provide some thoughts on the matter, as I said I'm not currently looking to solve a particular problem, but this topic is one that interests me.


probably a simple fix but i just cant work it out,  Basically this is a little program I made to calculate the hours I've worked in a day in decimal format, (becasuse I have to do it like that for my timesheet for work) works perfectly fine, but I decided to add in a feature where if I enter restart at anytime the whole program restarts.  I tried calling Time within Time but doing that restarts but then finishes the original after starting over. I also tried making a Restart function that calls Time and then call Restart but that didn't work either.  So I wanted to break out of them both and call the program again, is this possible or not?  def Time():     clear()     def is_valid_hours():         while True:             h=input("Hour: ")             if h=="restart": return "yes" #this line doesnt work (tried break)             try:                 h=int(h)                 return h             except:                 print("Please enter numbers!")     def is_valid_Minutes():         while True:             h=input("Minute: ")             if h=="restart": return "yes" # this is the other line (break tried)             try:                 h=int(h)                 return h             except:                 print("Please enter numbers!")     print("Please use time in a 24hour clock format when using this calculator")     print("Please enter arrival time:")     arrivalTimeHours=is_valid_hours()     arrivalTimeMinutes=is_valid_Minutes()      print("Please enter length of lunch break: ")     lunchBreakHours=is_valid_hours()     lunchBreakMinutes=is_valid_Minutes()      print("Please enter desired leave time: ")     leaveTimeHours=is_valid_hours()     leaveTimeMinutes=is_valid_Minutes()      if arrivalTimeHours>0:         arrivalTimeHours=arrivalTimeHours*60     arrivalTime=arrivalTimeHours+arrivalTimeMinutes     if lunchBreakHours>0:         lunchBreakHours=lunchBreakHours*60     lunchBreak=lunchBreakHours+lunchBreakMinutes     if leaveTimeHours>0:         leaveTimeHours=leaveTimeHours*60     leaveTime=leaveTimeHours+leaveTimeMinutes      totalTimeMinutes=leaveTime-(arrivalTime+lunchBreak)     decimalTime=totalTimeMinutes/60     print("Your decimal time is "str(decimalTime))     newTime=input("Would you like to do a new time?: ")     return newTime.lower()  newTime=Time() while newTime=="yes" or newTime=="ye" or newTime=="y" or newTime=="yah" or newTime=="yeah" or newTime=="yh":     newTime=Time() input("Press enter to close")   EDIT: I did try doing this aswell, it didn't work either.  def Time():     clear()     notQuitting=True     while notQuitting==True:         def is_valid_hours():             while True:                 h=input("Hour: ")                 if h=="restart":                     notQuitting=False                     return "yes"                 try:                     h=int(h)                     return h                 except:                     print("Please enter numbers!")         def is_valid_Minutes():             while True:                 m=input("Minute: ")                 if m=="restart":                     notQuitting=False                     return "yes"                 try:                     m=int(m)                     return m                 except:                     print("Please enter numbers!")          #rest of code

Given the following code (that doesn't work):  while True:     #snip: print out current state     while True:         ok = get_input("Is this ok? (y/n)")         if ok.lower() == "y": break 2 #this doesn't work :(         if ok.lower() == "n": break     #do more processing with menus and stuff   Is there a way to make this work? Or do I have do one check to break out of the input loop, then another, more limited, check in the outside loop to break out all together if the user is satisfied?


We're in the middle of redesigning our company website.  A request has come in from management to put in a holding page with basic contact info while the site is redeveloped.  Is this a good idea from an SEO standpoint?   What's the best way to implement this? I believe the temporary, simple HTML and CSS page would be uploaded to the server?

I've purchased a domain. I'm in the process of creating the website for that domain. This may take about a month.  In the mean time, what is the smartest thing to do with that domain, in terms of SEO?  For example, should I send a 204 No Content HTTP header? I know that's not the right thing to do but what is? I know that simply having a "Coming Soon" page is also bad for SEO.  Any advice?


Let $a_1,...,a_n$ be positive numbers. Show that $(a_1+...+a_n)(\frac{1}{a_1}+...+\frac{1}{a_n})\ge n^2$. Just not really sure how to approach this problem, any tips/solutions would be greatly appreciated.

If $x_1,...,x_n$ are positive real numbers and if $y_k=1/x_k$, prove that $$\left(\sum^n_{k=1}x_k\right)\left(\sum^n_{k=1}y_k\right)\geq n^2.$$   I've been learning induction, and I've come across this problem that I really can't even break down and begin to think about. I've been told it has something to do with Cauchy-Schwarz, but I cannot figure out how to apply it. I would appreciate help figuring out how to go about and formulate this proof. Thanks!


Please look at the following,      a) I finished my work this week.    This means I am either speaking at the end of the week or that I am speaking on any day of the week expecting no more work for the week. Am I right? Or are there few other scenarios? If yes, then please let me know.     b) I have finished my work this week.    Please tell me how this sentence is different from the above one? I fail to understand the difference.

I know the rule is to use past simple when you specify the time when the described action happened, but I strangely dislike this sentence and I'm not sure if the rule applies:   "It's the best movie I saw this year".  Shouldn't it be: "It's the best movie I've seen this year"?  Please, could you justify your answers? Thank you in advance!  Cheers


I was wondering if anyone had a simple way of finding the solutions to   $$n^2\equiv1 \mod a.$$  I think I read somewhere that the solutions are always  $$n\equiv\pm1 \mod a,$$  but the proof seemed inaccessible to me. Thanks!

Let $n > 1$ be any positive integer and consider $(\mathbb{Z}/n)^\times$. We want to find all elements $x \in (\mathbb{Z}/n)^\times$ such that $x \equiv x^{-1} \mod n$.  After testing a few different $n$, I am certain that the only elements will be $1$ and $n - 1$. This is certainly true when $n$ is prime. Showing it when $n$ is composite is more difficult:  Assume that $x \equiv x^{-1} \mod n$. Then $x^2 \equiv 1 \mod n$ and so $x^2 - 1 \equiv 0 \mod n$, which implies that $(x - 1)(x + 1) \equiv 0 \mod n$. Now if $n$ is prime, we could just conclude that $n | (x - 1)$ or $n | (x + 1)$. But I am unsure what to do in the case that $n$ is composite.


In the universe of Star Trek, there's said to be no use of money in the Federation (at least, not in Starfleet). They talk a lot about it in TNG; I don't want to get side-trekked into debating the best label for their system, but I have a few questions on their system.   When did this economic system become adopted? When a new planet joins the Federation, are they forced to adopt this system? Is it just Starfleet or all of the Federation? Is there some sort of indoctrination or other mechanism whereby the Federation prevents lazy individuals from coasting through life, or is that the individual's perogative?

I've always wondered this ... I recall fleeting references to the lack of a money system in TNG (something about abandoning the quest for material wealth), but was it ever explained why and how and when that came about? Is there a canonical explanation? And, what motivates them in that case -- why go to work if you're not getting paid and obviously, don't need to be paid because there's no money to buy anything? Were all the main races moneyless?


What is a few good abstract algebra books for second courses that is both readable for advanced undergraduate and beginning graduate student?  Or the intermediate one for self study?  Or at the same level as Herstein's Topics in algebra?

I recently read an abstract algebra textbook, "A first course in abstract algebra" by John Fraleigh. I am interested in continuing to do some more self studying. What is a good book for a second course in the subject for self studying? Thanks.


Can I extend a PHP class from two classes, one of which is abstract and other one is not? like:  class customer extends SomeControllerClass implements SomeAbstractClass { ... }   the reason to do is that I have my commonly used functions and logic in the abstract class.

If I have several classes with functions that I need but want to store separately for organisation, can I extend a class to have both?  i.e. class a extends b extends c  edit: I know how to extend classes one at a time, but I'm looking for a method to instantly extend a class using multiple base classes - AFAIK you can't do this in PHP but there should be ways around it without resorting to class c extends b, class b extends a


Location   Page:  Field: «when said by» [name=user]#user   When no result is found, the API responds with the plain text «No records.» Then JavaScript code tried to parse that text as JSON, with obvious fail.    As result, autofill looks like infinite loading, because the JSON.parse exception is uncaught.

When using the  and trying to filter by user, I get this after typing several letters:        Two letters work fine, third or fourth letter breaks the lookup.  Can this please be fixed?


The command below will send an email with a Subject and Body, but no Attachment. If I remove < /usr/tmp/BODY_OF_EMAIL I receive the email with Subject and Attachment, but no Body.  cat /usr/tmp/ATTACHMENT.xls | uuencode ATTACHMENT.xls | mailx -s "Subject of email!" emailaddress@company.com < /usr/tmp/BODY_OF_EMAIL   /usr/tmp/BODY_OF_EMAIL contains the text "Email Body."

I've created a script that runs every night on my Linux server that uses mysqldump to back up each of my MySQL databases to .sql files and packages them together as a compressed .tar file.  The next step I want to accomplish is to send that tar file through email to a remote email server for safekeeping.  I've been able to send the raw script in the body an email by piping the backup text file to mailx like so:  $ cat mysqldbbackup.sql | mailx backup@email.com   cat echoes the backup file's text which is piped into the mailx program with the recipient's email address passed as an argument.  While this accomplishes what I need, I think it could be one step better, Is there any way, using shell scripts or otherwise, to send the compressed .tar file to an outgoing email message as an attachment?  This would beat having to deal with very long email messages which contain header data and often have word-wrapping issues etc.


I'm been having graphics issue with Linux (blank screen or screen flickering). Since I can't solve them I'm trying another path. When I installed ubuntu I used safe graphics mode and everything went smoothly, so my question is what is it and how can I use them for my install, if that is possible.

On Ubuntu 19.04 and all its official flavors I observed that if I boot the LiveUSB in UEFI mode, there are options for live session and installation with safe graphics written beside them. However these options aren't available in legacy mode.    So, what is the purpose of this safe graphics mode? Is there any specific reason why they included in 19.04 and not on previous releases such as 16.04, 18.04 and 18.10?


public Crash getCrash() {     String uuidString = getString(getColumnIndex(CrashTable.Cols.UUID));     String name = getString(getColumnIndex(CrashTable.Cols.DRIVER1));     String insCo = getString(getColumnIndex(CrashTable.Cols.INSCO));     String policy = getString(getColumnIndex(CrashTable.Cols.POLICY));     String telephone = getString(getColumnIndex(CrashTable.Cols.PHONE));     String email = getString(getColumnIndex(CrashTable.Cols.EMAIL));      **Crash crash = new Crash(UUID.fromString(uuidString));**     crash.setYourName(name);     crash.setInsCo(insCo);     crash.setPolicy(policy);     crash.setTelephone(telephone);     crash.setEmail(email);      return crash; }   The line I marked is causing a NPE (uuid == null).  It seems to have problem with the fromString.  Here's the pertinent portion of the "Crash" class it's referencing.  public class Crash  {  private UUID mId; private String mYourName; private String mInsCo; private String mPolicy; private String mTelephone; private String mEmail; private Date mDate;  public Crash() {     this(UUID.randomUUID()); }  public Crash(UUID id) {     mId = id;     mDate = new Date(); }  public UUID getId() {     return mId; }   Is there something I'm missing?  I'm pretty new to this, so if there's some more information you're needing, please let me know.  Thanks in advance.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I fallowed  and watch some others. I used the video from the tutorial (the same one he used for motion tracking). I successfully imported the video, add the track points, and tracked them. When I set the orientation for the 3d scene it didn't really work. The camera was at a wrong angle the scene didn't really line up and the track points in the 3d scene weren't level like their supposed to be. The tracking points in the 3d scene did line up with the position of the original tracking point though.  Is there something I might be doing wrong missing a step or something?

Whenever I do camera tracking in Blender the reconstruction is always zooming out or not on the axis. I have a great quality camera, but the end results of the camera tracking always has the model sliding. If you have a solution please tell me.


I would like to know how you defragment and remove cookies on Ubuntu.

I don't want any answer saying that there's no need, please!


An image of the web page:  I want to put the button in the middle of the first box. I have followed a  from w3 schools  but it puts the button in the middle of webpage instead of putting it in the middle of the first box. My code:   .menus{     display: flex;     justify-content: space-evenly; }  .menu{     background-color: orange;     border: 3px solid grey;     width: 98vh;     height: 98vh; }  .menu1{     min-height: 50px; }  .menu2{     min-height: 50px; }  .menu1 h1{     magin-top: 50px;     text-align: center; }

                     <button>button</button>

How can I horizontally center a
 within another
 using CSS?

Foo foo


Title says all how do i make it so the obj is imported to the origin, it was working fine yesterday...

I have opened a new blender file and deleted the default cube, then imported an obj file . I did not see any thing so i selected it and i zoomed ,nothing appears.In the outliner i saw the object name ,But in the info panel i see that there isn't any verts/faces/edges.  When i opened the obj file in a text editor i found Mesh data in it. I tired this in all blender versions (2.78c/2.78.5/7.9). Can any one help how to view the mesh?


How can I check the convergence of $$\sum_{k=2}^\infty \frac{1}{k^2-1}$$ ? As it's almost the same as $$\sum_{k=2}^\infty \frac{1}{k^2}$$ which converges, it should converge, but I can't use a comparison between the two here, as $$\sum_{k=2}^\infty \frac{1}{k^2-1} \geq \sum_{k=2}^\infty \frac{1}{k^2}$$ so it wouldn't help. So how should I go about it?

I'm using the integral test to determine if this series converges. From what I have so far it seems that it diverges, but according to wolfram alpha it converges. Where is my mistake?   $$\sum_{k=2}^\infty {\frac{1}{k^2-1}} \to \int_{2}^M \frac{1}{x^2-1}dx$$  $$\int_{2}^M \frac{1}{x^2-1}dx = \frac{1}{2}\Big(\ln|M-1|-\ln|M+1|+\ln|3|\Big)$$  $$ \lim_{M\to \infty} \frac{1}{2}\Big(\ln|M-1|-\ln|M+1|+\ln|3|\Big)$$


I have list of book titles and I have to list chapters like this.  Title 1         Chapter1        Chapter2        Chapter3        Chapter4 Title 2         Chapter1        Chapter2   So, I have list inside a list. I can get list of books (and titles) but when i reference their chapters i get nothing. well, how can I do that?  <% foreach (var item in Model) { %>

             	                              <%= Html.Encode(item.Text) %>
          <% foreach (var chapters in item.Chapter){%>
                              <%=Html.Encode(chapters.Number)%>             	                              <%=Html.Encode(chapters.Text)%>
         <% } %>
          <% } %>

When i have a relation between two entities in my model:  [GroupMember] (*) ----- (1) [User]  and tries to select items from this relation with LINQ:  From entity in _user.GroupMember select entity  I always get an empty result unless I load the relation first with following statement:  _user.GroupMember.Load()  Is there a way to avoid loading the relations like this?


Prove that there isn't a sequence of continuous function on $[0,1]$ that converges pointwise to the function $f$ on $[0,1]$ defined by $f(x)=0$ if $x$ is rational and $f(x)=1$ if $x$ is irrational.  What I've tried:  By contradiction: Suppose that indeed exists one(say $f_n$) and let's take $a$ in $[0,1]\cap \mathbb{Q}$, then $f_n(a)$ approaches to $0$ when $n$ is sufficiently large, say $n\ge N$. Let's take in particular $n=N$. Since $f_N$ is continuous, there exists a neighborhood of $a$, $(a-d,a+d)$, in which $f_N(x)$ is near $f_N(a)$, and thus is near to $0$. Let's take now $b$ irrational in that neighborhood. Then, for $n$ sufficiently large,say $n\ge K$, $f_n(b)$ is near $1$. This should be the contradiction, since $b$ would be at the same time near $0$ and $1$ (suppose I've chosen the right epsilons). The problem is that the $K$ may be larger than the $N$, and so there is no contradiction. If I then try to make the $N$ larger, then I modify the $d$, which modifies the $b$, and therefore there's no sense in taking that particular $b$. I've also tried to apply continuity to $f_k(x)$, but the neighborhood in which $f_k(x)$ is near $f_k(b)$ (which is near $1$) may not have anything in common with the previous neighborhood...  I wish you could help me.  Thanks in advance.

Prove that there does not exist a sequence of continuous functions $ f_n :\left[ {0,1} \right] \to R $ such that converges pointwise, to the function  $$f(x)=   \begin{cases}     0 & \text{if $x$ is rational},\\\\     1 & \text{otherwise}.   \end{cases}. $$  I have no idea How can I prove this. Prove that there no exist such sequence if the convergence is uniform, it's easy, because the limit would be continuous, but here I don't know How can I do. I suppose that some "nice" properties are "preserved" in the limit, in this kind of convergence, but I don't know any of them.


Good afternoon,  The square root of $-1$, AKA $i$, seemed a crazy number allowing  contradictions as $1=-1$ by the usual rules of the real numbers. However, it proved to be useful and non-self-contradicting, after removing identities like $\sqrt{ab}=\sqrt a\sqrt b$.  Could dividing by $0$ be subject to removing stuff like $a\times\frac1a= 1$?  A way I can think of defining this is to have $\varepsilon=\frac10$. Remeber it may be that $\varepsilon\neq\varepsilon^2$, we don't know whether $\left(\frac ab\right)^n=\frac{a^n}{b^n}$, and other things alike; so they can't disprove anything.  This seems fun! What about defining a set $\mathbb E$ of numbers of form $a + b\varepsilon$? There would be interesting results as $(a+b\varepsilon)\times0 =b$.  Are these rules self consistent? Can such a number exist? If not, what rules can we change to make it exist? If yes, what can we find about it? How can it help us?   If there is no utter way of dividing by zero without getting a contradiction no matter the rules used, how can that be proven?

I came up some definitions I have sort of difficulty to distinguish. In parentheses are my questions.   $\dfrac {x}{0}$ is Impossible (  If it's impossible it can't have neither infinite solutions or even one. Nevertheless, both $1.$ and $2.$ are divided by zero, but only $2. $ has infinite solutions so as $1.$ has none solution, how and why ?) $\dfrac {0}{0}$ is Undefined and has infinite solutions. (How come one be Undefined and yet has infinite solutions ?) $\dfrac {0}{x}$ and $x \ne 0$, it's okay for me, no problem, but if someone else wants to add something about it, feel free to do it.


I have number of strings like   var str="#{ZyDt8spGZOA.mI8uHaT7o47}+#{z3PENrRf0cn.mI8uHaT7o47}+#{lhUBSvCMPWu.mI8uHaT7o47}+#{YNpiWU7fw9m.mI8uHaT7o47}";   I need to get the content only inside the curly bracket to an array. (In the above case array of length 4).  How can I achieve this?

Unfortunately, despite having tried to learn regex at least one time a year for as many years as I can remember, I always forget as I use them so infrequently. This year my new year's resolution is to not try and learn regex again - So this year to save me from tears I'll give it to Stack Overflow. (Last Christmas remix).  I want to pass in a string in this format {getThis}, and be returned the string getThis. Could anyone be of assistance in helping to stick to my new year's resolution?    Related questions on Stack Overflow:


I wrote a simple regex pattern with corresponding sample     var regex = @"_if_.*_else_.*_endif_";     // 4 nested regex pattern    var sample = @"_if_111_else_222_if__if_333_else_444_endif__else_555_if_666_else_777_endif__endif__endif_";     var matches = Regex.Matches(sample, regex); // count : 1 ?!?!?   Result of matched variables returns only 1 record while I expected it to return 4 records.   _if_666_else_777_endif_ _if_333_else_444_endif_ _if__if_333_else_444_endif__else_555_if_666_else_777_endif__endif__endif_ _if_111_else_222_if__if_333_else_444_endif__else_555_if_666_else_777_endif__endif__endif_   How can I get all patterns that exists in string by regex? Is there a better way?

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


How would you create A pop-up password dialogue using zenity (or other application) so that when a user tries to access a specified Applictaion it asks for a password

I want to limit access to running apps with a password. Is that possible? I have an app in the tray icon and I want to close it for unauthorized access.  Greetings


I have Ubuntu 18.04 and python 3.7. uname -a Linux username-laptop 4.15.0-109-generic #110-Ubuntu SMP Tue Jun 23 02:39:32 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux  When I run sudo apt-get update I get this error : E: The repository 'http://dl.bintray.com/aluxian/deb stable Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'https://dl.bintray.com/aluxian/deb dev Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  I tried  solution but I am also unable to open Software and updates.

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


I am currently trying to generate makefile that can handle generating dependancies for a C and C++ raytracer project. I need assistance in generating the include files being used.  # Makefile  # Default Directories: #  bin  the binary directory #  inc  the include directory #  obj  the object directory #  src  the source directory BIN_DIR  := bin INC_DIR  := inc OBJ_DIR  := obj SRC_DIR  := src  # The compiler: gcc for C programs, define as g++ for C++ CC       := gcc CXX      := g++  # Compiler flags: #  -g      adds debugging information to the executable file #  -Wall   turns on most, but not all, compiler warnings #  -O2/O3  defines the optimization level of the program(s)   CFLAGS   := -g -Wall -O2 CXXFLAGS := -g -Wall -O3  INCLUDES := -I$(INC_DIR)   My file structure is the following:  Raytracer   |   |___bin   |   |___inc   |    |__Geometric   |           |____Vector3D.h   |   |___obj   |   |___src        |__Geometric        |    |______Vector3D.c        |    |______Vector3D.cpp        |        |___Main             |__Main.c             |__Main.cpp    In the Vector3D.h file, I used a template format in and initialized:  #ifndef __VECTOR3D_H__ #define __VECTOR3D_H__  #include <math.h> #include <stdio.h> #include <stdlib.h>  // C Methods defined surrounded with __cplusplus & extern "C" {...} #ifdef __cplusplus #include <sstream> #include <iostream>  namespace Geometric {     template <typename T = float>    class Vector3D { // Vector3D       // Constructors already defined...      // Methods already defined...      // Etc...     }; // The 'Vector3D' Class       // Implemented constructors...      // Implemented Methods...      // Implemented Etc...  } // The 'Geometric' Namespace  #endif /* __cplusplus */ #endif /* __VECTOR3D_H__ */   When defining the Vector3D.c & Vector3D.cpp files should i use:  #include "Geometric/Vector3D.h"  // Or  #include <Geometric/Vector3D.h>  // Or does it matter...

In the C and C++ programming languages, what is the difference between using angle brackets and using quotes in an include statement, as follows?   #include <filename>  #include "filename"


Example Scenario: A close competitor has their own website: example.co.uk but has not registered example.com, so example.com if freely available.  Put aside any ambitions of 'easy' / blackhat SEO benefits (such as discussed and disapproved in  ), my question is different.  It could very reasonably be expected that some (many) customers may type example.com (ie the unregistered domain) instead of example.co.uk, the live domain.  At the moment those potential customers end up on a hosting company page offering the as yet unregistered domain coke.com for sale.  Would it be a good strategy, and legal, if we registered that domain and instead redirected potential customers to our website which sells similar products?  Assume the unregistered example.com has been checked and has no adverse history in terms of SEO. In fact, it has never been registered before.  Would this action simply be good business acumen to take competitive advantage of a piece of online real estate that the competitor has - to be frank rather poorly - failed to grab for himself?   I accept that customers typing example.com (and expecting to land at example.co.uk) may be a little surprised/dismayed to end up at our website. However, surely that's better than ending up at a domain hosting company telling you the URL doesn't have a website and is available for sale.  Especially if our website had a brief pop up saying something like      Sorry, example.com was not a live website, so we've grabbed it and are taking you to here instead to hopefully quench your desires!   The domain name is simple words, not a trademarked phrase, Eg. "BestShoesInLondon".

Imagine my competitor is getting 1000s of views a day and is established in Google search engine.  I plan to launch my website in a weeks time but will have to work hard to get into google search results  If my competitor has the domain www.example.com , can I buy the domain www.example.co.uk and then redirect that to my website?  I figure some people may accidentally put .co.uk instead of .com  Would this me illegal in any way , or is it fair game as they haven't bought the domain, meaning I could possibly look to selling it to them?


Could someone help me understand how to prove $P(A'\mid B) = 1-P(A \mid B)$? I tried to make it so:  $P(A'\mid B)= \cfrac{P(A'\cap B)}{P(B)}$ but I'm not sure how to continue.   (I see that there is a question asking to prove $$P(A|B) = 1-P(A'|B) $$ How is it possible that P(Not A |B) would yield the same proof as P(A|B)?

Does this identity hold for all events?  $$ P(A|B) = 1-P(A'|B) $$  Logically speaking, if the probability of $A$ given $B$ occurred is $X$, shouldn't the probability that $A$ does not occur, $A'$, given $B$, be similarly $1-X$?  There is a related question .  This is the closest that I could get to proving (or disproving) it:   $P(A\cap B)=P(A)-P(A' \cap B)$ $P(A|B)P(B)=P(A)-P(A'|B)P(B)$ $\therefore P(A'|B)= \frac {P(A)} {P(B)}-P(A|B)$   Are there are certain formulae which can be used to prove this? Or does the identity only hold under certain situations, and if so, what kind of situations?  Thanks.


I just came to know about this new policy of Stack Overflow.     Sorry, we are no longer accepting questions from this account.   Initially it was funny that people are losing their accounts :-D. But I think it's a very good step to create a clean community.  Honestly saying I did same mistakes like if I got some downvotes for particular question, I deleted that one. And sometimes I asked a question and deleted that question after a while.  So my question is: how can you know that you are quite close to losing your account? Means there will be some kind of progress bar, some threshold value, etc. I hope you are getting what I am trying to say.  It's kind of funny, but seriously I want to know about this.

Another "miséricorde":  Consider  (emphasis added):  I think its okay, please dont take any efforts for me. I personally do not feel the system helps ask good questions. I dont know why asking for a software in this case is bad. Basically I needed a command that would give me this data. There is no other way I could have asked the question. I could have changed the question just for the sake of changing. I feel I am better off elsewhere. Thanks for your very very prompt responses. Regards. Bye. – user1744649  We just lost another user due to inadequate guidance on what questions are allowed.  The  by the time they are banned has been proven incorrect. Given that , we need a better way to make sure that users can understand how to ask good questions and what types of questions are allowed. I suggest that we warn newcomers, in a clear but positive tone, when one of their questions has been closed, downvoted (to a score of -2 or lower), or deleted, so that they don't repeat the same mistake.  This is probably best done the next time the user asks a question, and should appear as an "interstitial" page prior to reaching the actual Ask Question form.  The page should not appear to users:  with at least 50 (or perhaps 75 or 100) reputation that have asked a good question since the last downvoted/closed/deleted question that have fixed a bad question and had it reopened/undeleted/upvoted.  The content of the page should be adapted based on the specific problem with the previous question.  I would imagine something similar to the following (example for a question closed as off topic on Super User):  Before you ask another question... One or more of your previous questions have been closed as off topic. The scope of on-topic questions is defined in the , as follows:  What kind of questions can I ask here? Super User is for computer enthusiasts and power users. If you have a question about …  computer hardware, computer software, or personal and home computer networking  and it is not about …  programming and software development, video games or consoles, websites or web services like Facebook, Twitter, and WordPress, electronic devices, media players, cell phones or smart phones, except insofar as they interface with your computer, issues specific to corporate IT support and networks, asking for a shopping or product recommendation,  … then you’re in the right place to ask your question!  Please make sure that the question you are about to ask is on topic as described above. If you need help determining whether your question can be asked on this site, you can ask for advice on  or . You may also want to edit your previous question to address any problems associated with it. To ensure a high standard of content quality and prevent disruption to the community, users who repeatedly post low-quality questions  Continue  The  doesn't address this issue as it is shown only to users with 10 reputation or less (rather than up to 50 and possibly higher) and does not address the specific problem with previous low-quality questions.  The point of this feature request is to provide a easily understood targeted message that actually teaches the user about what happened with the previous question he or she asked.  The EULA is generic and may not have conveyed the intended message clearly if the user still asked a low-quality or off-topic question. For reference,  currently has 143 reputation and the proposed message would probably have been shown after the first closed or deleted question. I know this can be a complex feature to implement, since it needs to be adaptive, but this should help eliminate confusion on what the rules are and minimize the incidence of good-faith users getting post-banned.


Is it '12 month's remuneration', '12 months' remuneration' or '12 months remuneration'? New Oxford Style Manual says it does not get an apostrophe is not used in 'adjectival constructions' e.g. three months pregnant. Confused.

I’ve always understood that the phrase two weeks usually turns into two weeks’ when used as a modifier as in   I’m giving my two weeks’ notice.  I get two weeks’ vacation. (“two weeks’ holiday” for Brits)   with an apostrophe on the word weeks’, indicating that the vacation “belongs” to the weeks.   One way to explain this is the phrase “two weeks of vacation” being contracted to “two weeks’ vacation” – the vacation is “of” the weeks; that is, it is possessed by them.  But I’ve seen a lot of people omit the apostrophe in casual writing, and thinking about it, it seems plausible that the noun vacation would be plainly modified by the adjectival phrase two weeks.  But on the other hand, shouldn’t adjectival phrases be hypenated, namely two-weeks vacation?  Yet that seems wrong, too: the hyphenate should be singular, two-week vacation (like two-tone shoes) because .   touches on this (and references a good ) but doesn’t explain why the plural must be possessive in this case.   suggests that two weeks might be adverbial rather than adjectival, and thus resists being used attributively. But that still doesn’t quite explain this particular muddle of pluralization, possession, and attribution.  Given all this, why should “two weeks vacation” be written “two weeks’ vacation” with a possessive apostrophe?


I have seen on many sites a section labeled "Comments," referring to an area where you can leave a message for someone, or on something. When referring to this section is it correct to say Comments Section or Comment's Section or even Comments' Section  From what I've learned about apostrophes is that you use them when you are denoting something belonging to something else.  i.e., Alice's watch. Would the section, in this case, belong to the Comment(I think I've heard the word "Possessive," is that correct?)?  Or would it actually belong to the "multiple comments" and be Comments' instead?  A second part to this, instead of making another question. If an apostrophe is in fact needed, would referring to a user's section? i.e.,  Ralph's Comment's section... I'm just curious if you could do 2 words in a row with apostrophes. Thanks.

I've read a great article about the . But there are still some points that are unclear.  Why do we say...   school project but not school's project? car service but not car's service or even cars' service (plural form)? apostrophe usage but not apostrophe's usage or apostrophes' usage?


Is money a countable noun?  We had a little/few money left, so we decided to have a meal in a cheap restaurant so that it costs us a few rupees.   Here rupees is the currency of India.  I wonder few rupees make sense. But why we can't use few money here?

page suggests that we use much with only uncountable nouns whereas the use of many/several is limited to countable nouns only. So I conclude that money is uncountable noun as I've heard people saying phrases like      So much money!   But, We do count the money in our daily life then why is it that money is considered an uncountable noun instead of countable? What if I say      I have $500 to spend   Wouldn't the money be considered countable in this case?  Edit The question may be considered duplicate of the suggested question but, in my opinion, the question on that link itself is not answered properly.


Most entries for undead say they are animated by magic, usually described as dark, necromantic, etc, but still magic. Could these undead be destroyed by Dispel Magic if upcast enough to match the level of magic used to create that Undead?   The only undead creature I could find whose entry mentioned Dispel Magic was the Lich, and use of Dispel Magic only freed any trapped souls in the Phylactery, and didn't dispel the phylactery itself. Other than that, most undead entries talk about how they are magically animated. (Banshees being one exception I found, with no mention of magic involved in creating them)

According to the MM skeletons are animated by dark magic.  They heed the summons of spellcasters who call them from their tombs. The magical energy motivates a skeleton to move and think in a rudimentary fashion.  I assume that a similar effect animates and controls all undead.  So if I cast dispel magic on a skeleton or any other undead do they cease to be animated and can't move or act?


I'm going to build a city and I need to know where the center is. I'm using version 0.6.1. How can I figure out where the exact center is located?

I'm currently building a town in Minecraft Pocket Edition and I'm wondering how many blocks long and how many blocks wide the world is.


I know someone trying to remember the title of an old book but they can only describe it as this ...  The “protagonist” is a member of a spherical alien race. They use needle thin “jets” of liquid for locomotion and defence. The beginning of the story shows how the protagonist grew up on his home world, amongst his fellow aliens. They spent a great deal of time trying to avoid their natural predators, a race of scorpion like aliens, that distended their stomachs outside their bodies to digest prey. There was a third race of armoured plant-like aliens also living on the world.  The second half of the story see the “protagonist” leave his home world and team up with a human… and highlights the clash between the two very different physiologies. (for example… the alien uses the word “food” as a swear word as it is a disgusting concept to him… given he derives energy from sunlight and built in chemical process)

I'm trying to identify a book, where several different races (I think at least 3) who all have just one particular sense (seeing, hearing) must cooperate as a mixed group in some kind of competition or race that involved navigating a kind of obstacle course, building, or maze, that possibly involved challenges, where each of the senses and sometimes their combination was necessary to advance.  I think the races initially hated each other (prejudices), but the representatives of at least one group involved in this competition learned to respect each other during the events.  Must be older, before 80s. I read the novel in German, but it was translated from English, as most SF here was at this time. I've no idea if it was aimed at adults or young adults. I don't remember names. I don't remember the perspective. The race was at least a substantial part of the book. It might have been a small book. That's about all I can remember.


I have a desktop computer with:   Intel Pentium(R) Dual CPU E2180 @ 2.00GHz × 2  GeForce GT 610/PCIe/SSE2 graphics.   Until recently it was running Ubuntu 16.04 LTS and 16.10 in dual boot.  Both versions would suspend and awaken correctly.  About a month ago I upgraded the 16.10 installation to 17.04.  At about the same time, there was a large update to 16.04.  Since then neither version will suspend and awaken.  On the sleep button or suspend from the menu or suspend from the power settings, the machine shuts down completely and will only restart from cold with the power button.  There are no errors reported in the pm-suspend log.  I have Nvidia driver 381.22 and the update to 17.04 from last Friday installed.  Can anyone help to resolve this.  There have been no hardware or BIOS changes.  I have tried 375 and 378 as well as 381.09, all with the same result.  The problem occurs on suspend, not on wake up.  The power light on the box goes off after suspend.  It used to flash slowly while suspended.  After today's updates, with kernels 4.4.0-78 and 4.10.0-21, neither version will suspend correctly.  16.04 is using driver 375 and 17.04 is using driver 381.

I've been using Ubuntu for about five years now, and I still can't make it suspend when I want to. It's quite irritating that I can program up a storm, hack the machine in numerous other ways, and yet, and yet when I try to make it suspend or debug suspend, I fail miserably.  I need help.   Where do I begin to find the problem? What do I do to fix it? I'm placing a bounty on this, because I've literally lost hours of my life to this problem, and leaving my computer on ALL the time is terrible.  The symptoms:   Pressing suspend brings my computer to a state where it has a blinking cursor, the fans are running, it seems that the HD has turned off (I think), and I can't do anything to bring it back from this state (short of a hard reboot). Possibly related: My fans stay on even after a shutdown, and even then, I have to press the power button for five seconds before I can start it up again. I don't know what logs to look at to debug the problem, and I imagine they'd get nuked on reboot anyway.   Please, please help. This drives me completely nuts, and I've been living with it for over a year.


I saw below sentence:     Her job is to clean the hall.   So can I also say like:     Her job is cleaning the hall.   It's present participle or gerund?  What's the different meaning between these two sentences?

What is the difference between the following:  Things started to work again. Things started working again.


I've been looking for Star Trek fonts or symbols for LaTeX lately, but unfortunately I couldn't find any. Do any of you know if there is a Star Trek font or character set?

I want to use a really cool open-source OpenType font with my LaTeX document.  I was told that either I could go through a long process of converting the OpenType font to one useable by LaTeX, or I should instead switch to using XeTeX.  Is there a way for me to use an unmodified OpenType font with my LaTeX document (and existing LaTeX installation)?


The effects of the GW150914 gravity wave burst were barely observable with state of the art instruments, i.e. LIGO. What would the effects of  GW150914 gravity wave burst be on observers much closer that 1.3B LY? For example, in the same galaxy 30,000 LY from the black hole merger. Or on a planet orbiting a few dozen AU from the event. I have read that the wave contained energy equivalent (in the MC^2 sense) to three solar masses. How is this energy transferred to a nearby planet?

Assume two black holes in the most common size range, spiraling into each other until they merge. The event releases significant amounts of energy via gravitational waves, which warp the space-time.  If the distortion is powerful enough, it would get noticed in daily life, or perhaps even detected by the proprioceptors in the human body.  How close, as an order of magnitude estimate, would you have to be to the merger to perceive it like that, without any instrument?


Pinter's textbook "A book of abstract algebra" asks to prove the following:     There are infinitely many irreducible polynomials in $\mathbb{Z}_{5} [x]$.     Here's my attempt to prove it any field $\mathbb{F}$:  Let $F$ be a field. Suppose that there are finitely many irreducible polynomials in $F[x]$, say, $r_1 , r_2 , \ldots , r_n $. Then $r_1 r_2 \ldots r_n +1 \in F[x]$. Hence, by the factorisation into irreducible polynomial theorem tells us that  $$r_1 r_2 \ldots r_n +1 = k( r_1 r_2 \ldots r_n)$$  for some $k \in \mathbb{F}$. But then $r_1 r_2 \ldots r_n$ would be an associate of $1$. Thus each of $r_i$ must be a constant polynomial which contradicts the definition of a irreducible polynomial.    But I suppose this is not what the author wanted. I was wondering if there's any way to generate such irreducible polynomials over $\mathbb{Z}_{5}$. It looks to me as if $x^n+1$ where $n$ is even is a irreducible polynomial but I couldn't prove it. Any hints?

I can intuitively understand that there are infinitely many irreducible polynomials in $\Bbb{F}_p[X]$, where $p$ is a prime number, but I'm having a hard time actually proving it. What proof strategy should I take for this?


I have a fresh kubuntu installation and breeze themes icons are missing.    I already have cleared my cache by moving .kde and .cache. I have already tried to change theme but no success.  My main concern is that dolphin looks very different then it should. See dolphin screen-shot.    Can anyone help me with this?

I could not find this specific issue on Google. After I updated from Ubuntu 15.04 to 16.04 LTS, next to xfce4 and unity not working correctly, also the icons from the Breeze icon theme are behaving in an unexpected manner. I have tried to reconfigure and reinstall these packages, however the problem remains.    Icons such as the Firefox icon are missing Instead of the blue folder icon I am seeing a simple flat white icon, this happens as well for icons of files with extensions of images, text, jars, etc.   .  Thanks for your help.


I want to know what the use of hats in Stack Exchange is.

What exactly is a hat?  I have seen a lot of people arguing the significance of hats and the limited edition hats. I know the hats are sort of linked to the Winterbash stuff, but what exactly is a hat, what does it do, how do I get one?  Is there a full list of hats?


How can I calculate the integral $\int_0^1{\frac{x-1}{(x+1)\ln x}dx}$? Since there is $\ln x$ in the denominator, I tried using Leibnitz integral rule. Let $I(t) = \int_0^1{\frac{x^t -1}{(x+1)\ln x}}dx$, then $I'(t) = \int_0^1{\frac{x^t-1}{(x+1)}dx} $, but I can't get any further.. Wolframalpha tells me it's $\ln (\frac{\pi}{2})$, but not how.

Evaluate the following integral $$\displaystyle I=\int_{0}^{1}\frac{x-1}{(x+1)(\ln x)} \mathrm{d}x $$ My work: I tried it by letting $\displaystyle I(a)=\int_{0}^{1}\frac{(x-1)x^a}{(x+1)(\ln x)} \mathrm{d}x$ and then $\displaystyle I'(a)=\int_{0}^{1}\frac{(x-1)x^a}{x+1} \mathrm{d}x$. Now $\displaystyle I'(a)=\int_{0}^{1}x^a \mathrm{d}x-\int_{0}^{1}\frac{2x^a}{x+1} \mathrm{d}x$ Now if $\displaystyle J(a)=\int_{0}^{1}\frac{x^a}{x+1}\mathrm{d}x$ , then by applying integration by parts, we get the reccurence relation $J(a)+J(a-1)=\dfrac{1}{a}$ and we can solve it then, but the thing is, we neet to find $I(0)$ ,so even if we compute $J(a)$, it wouldn't be defined at $0$ and so would $I(a)$, then how do I find $I'(a)$ by other method? I also tried the substitution $x \to \frac{1}{x}$, which yields $\displaystyle I=\int_{1}^{\infty}\frac{(x-1)}{(x+1)(\ln x)} \mathrm{d}x$ and when I saw their graphs, it clearly doesn't seem that the area under the graph of this function from $0$ to $1$ and from $1$ to $\infty$ are equal. I would appreciate if someone could  continue from my method and other solutions are also welcomed...


For which rings $A$ can elements be written as a finite product of irreducible elements?    I feel like this is true for almost all rings I have ever encountered, but when do I know that I can write any nonzero nonunit element of $A$ as a finite product of irreducible elements? (I am not assuming the product is unique here.)  In particular, if $A$ is an affine $k$-algebra can I always do this? ($k$ algebraically closed field)  Thanks!

I want to prove that in a noetherian ring $R$ which is also an integral domain, every non invertible element can be expressed as product of irreducible elements.   I really do not know where to start. Can someone give me hint how to prove this?


When managing References, seem to me to be two-ish, options:  Either for each Project, I maintain a database of the relevant resources (In say a bibtex file), and for each new piece of work I start a new one.  Or I maintain a single "Monolithic" collection of resources (still in a bibtex file),  for everything I do, and I carry that around with me for years.  There are some in-betweens, such as having a Monolithic Collection, which I copy references from at the start of a project into a Project Collection, which I then use (and update) during the project, then copy either all or some of it back into the main collection.  What are the Pros and Cons of each approach? Am I thinking about this in the wrong way?

Self-explanatory. I would be most interested to hear from researchers who have published a fair amount, decided one way or the other wasn't working for them, so switched — and why.  Related advice / observations welcome: e.g. "why the hell would you need more than one .bib file?"


I'm trying to find a single adjective that would fit the best to the following person's trait:     One who thinks knows everything/best, and often doesn't listen to orders and instead completes some task his/her own way.    This person, while intelligent, is right about 50% of the time, when doing things its own way.   So far I've thought of independent, idiosyncratic and stubborn, but these words don't imply the "knows everything/best" part of the trait.

What would you call a person who doesn't want to learn new things and even maybe thinks that this is unnecessary since he knows enough already?  An ignorant person?


I can't figure it out why we put 'high' after noun 'layer'. What does it mean? When can we use adjectives after nouns? Is there any difference in the meaning if we swap the position of the adjective and noun in the example above?     ozone   a form of oxygen that is found in a layer high in the earth's   atmosphere.

I want to describe my business and want to refer to it in a sentence.  I am trying to say:      "In 2015 we established a business (that is) named X".   Intuitively, the "that is" part is redundant, and makes the sentence more cumbersome. But I cannot think of a reason why we should be able to drop the verb.  Is the version without the "that is" part grammatically correct? How can it be explained?


\begin{table}[htbp]         \centering         \small         \begin{tabular}{|c|c|c|c|c|c|c|c|c|}             \hline                 Wavelength & Model & Package & Emmitter type & Manufacturer & Power (mW) & Iop (mA) & Ith (mA) & Vop (V)\\             \hline                 405 & DL-7386-101HG & TO-56 & single & sanyo & 50-70 & 70 & 35 & 4.8\\             \hline                 450 & PL 450 & TO-38 & single & osram & 50-90 & 120 & 30 & 5.5\\             \hline                 638 & ML520G54 & TO-56 & single & mitsubishi & 90-100 & 150 & 50 & 2.7\\             \hline                 655 &  DL-5147-242 & TO-56 & single & sanyo & 30-50 & 80 & 40 & 3.8\\             \hline         \end{tabular}         \caption{Laser specifications}         \label{tab:Laser_Specs}     \end{table}   The above is my code for creating a table and when compiled it gets beyond textwidth. How can I solve this issue without altering the font size ?

I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met:   The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction.   What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist?


I am working on an apex class which is making a webservice callout to an external system and with the response that I get, I am updating couple of fields on the Account object. Unfortunately, this webservice is not batched or bulkified, so I need to call this service once per account and process it one at a time. The webservice response is sometimes too big (around 1MB when saved to a file). Most of the responses are processed fine and very few of them failing with the error message "Regex too complicated". The statement that is causing the response processing to fail is below. strResponse = strResponse.replaceAll('"system"','"smsystem"');  As you can see, I am not using a pattern matcher or any kind of Regular expression. I am not sure why I am getting this error message with just a replaceAll() method. Can someone help me in avoiding this error message?

Given   A JSON string with Apex reserved words (like "currency":"USD" and otherwise undeserializable-into-Date type (like "someDate":"0001-01-01T00:00:00Z" ) An apex method that uses   String s = s.replaceAll('"currency":','"currencyX":')             .replaceAll('"0001\\-01\\-01T00:00:00Z"','null');    before deserializing into a custom Apex type with property String currencyX and Date someDate  When  The incoming Apex string is very large (> 1MB)  Then  Uncatchable error: Regex Too Complicated     What to do?


Problem: Given that $\lim_{n\to\infty }a_n=L$ and $m_n=\frac{\sum_{1}^{n}a_k}{n}$. Prove that $\lim m_n=L$  Proof: We have $\sum_{1}^{n}a_k=na_k$, so $m_n=\frac{\sum_{1}^{n}a_k}{n}=\frac{na_k}{n}=a_k$ and $\lim a_k=L.\square$   Is this a correct proof? I am confused with the subscripts $m$ and $k$ and not sure if I am using the right one in the right spot, in the proof. Thanks.

Prove that if $\lim_{n \to \infty}z_{n}=A$ then:  $$\lim_{n \to \infty}\frac{z_{1}+z_{2}+\cdots + z_{n}}{n}=A$$ I was thinking spliting it in: $$(z_{1}+z_{2}+\cdots+z_{N-1})+(z_{N}+z_{N+1}+\cdots+z_{n})$$ where $N$ is value of $n$ for which $|A-z_{n}|<\epsilon$ then taking the limit of this sum devided by $n$ , and noting that the second sum is as close as you wish to $nA$ while the first is as close as you wish to $0$. Not sure if this helps....


I am currently a second year science student double majoring in biochemistry and applied statistics. The stats course im doing this semester (Statistical Theory) is focused on joint probability distributions, moments of univariate distributions, moment generating function, distribution of sample statistics and parameter estimation. We have no recommended textbook for this course (instead my college offers their own notes with tutorial exercises at the end). I wrote my first test for this course and it turns out that the tutorial exercises are extremely easy (and few) in comparison. Can anyone recommend textbooks (with practice questions) so i can become more confident with anything they might throw my way??  Thank you

I took several statistics courses in college but I found that my education was very theory driven.  I was wondering if any of you had a text in Applied Statistics (at the graduate level) that you recommend or have had good experience with.


When making bun, Yeast & salt should not be mixed at the same time? Will kill Salt the Yeast, salt is a hunter?

I was told by a friend that, when making pizza dough, I should add the salt at a later stage than the yeast, because it might disturbe the yeast from doing its thing...  I apologize for not having anymore concrete information, I just wanted to check this...


Here is my code (question listed below):     import java.util.Scanner;  public class ExampleCode {  /**  * B. Stephens  */ public static void main(String[] args) {      Scanner input = new Scanner (System.in);      String secretPhrase = "show me the money";     boolean notDone = true;      while (notDone = true){         System.out.print("Guess the puzzle: ");         String puzzleGuess = input.nextLine();         if (puzzleGuess == secretPhrase) {             System.out.println("Congratulations! You guessed the puzzle!");             notDone = false;         }     }  } // end main   For some reason, the program isn't recognizing when my input (puzzleGuess) is the same as secretPhrase.  It seems like there is no reason the correct input shouldn't end the program.  Thanks for any help!

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 think this screenshot of the responses tab of my profile's activity tab says it all.    Using a wide-screen monitor, fullscreen. Firefox 68.4.2esr on macOS 10.14.6

and        ()   I just noticed that change. I didn't find new reports under .  Note the names and badge count in the first screenshot, and the badge count in the second one.  PS I can't link to the responses tab as it shows only to the profile owner.


I have a bunch of text files in several directories I want to copy into another. What can I do, instead of going inside each directory and cp *.txt in this directory?

I have a large folder of pictures (thousands), and I have a long list of files, by exact file name, that I need to copy to another folder. I want to know if there is a way I can select several specific files from this folder, by name, and copy them to another folder, using the terminal, without copying them individually?


My work computer is Ubuntu desktop, but I am most familiar with Windows. Because of this I dont know all the smart shortcuts that you can use in Ubuntu.   Example: I know there is a shortcut for terminal start (Something with Ctrl+T), but I can remember it.  Is there any PDF that I can print (and put up on my wall) with a list of shortcuts for Ubuntu desktop?

In Unity, are there any pre-defined shortcuts, e.g. to open the dash or unhide the launcher?


Is it possible with regex to repeat a captured group an amount of times with the added restriction that the amount to repeat is also found in a capture group?  Example:  Regex: /(a)([0-9])/g String: ba1na3na2 Expected result: banaaanaa   I have never seen anything that does this, but maybe I have been looking in the wrong places. Note: I am using Perl - but I am interested to see answers for other flavours as well.

I am learning Perl, so please bear with me for this noob question.   How do I repeat a character n times in a string?   I want to do something like below:  $numOfChar = 10;  s/^\s*(.*)/' ' x $numOfChar$1/;


For whatever reason I'm unable to produce bibliography with the BibLaTeX package in MiKTeX. I'm running the 32-bit MiKTeX 2.9.5105 on Windows 7. I've conjured the simplest code I could think of and it still wouldn't work:  \documentclass{article} \usepackage{biblatex} \addbibresource{justin.bib}  \begin{document}  Hello! \cite{justinB}  \printbibliography  \end{document}   The bib file looks like this:  @article   {justinB,    AUTHOR  = "Bieber, Justin",    TITLE   = "{Baby baby baby (ohh)}",    PUBLISHER = "Ludacris Inc.",    YEAR = 2010   }   And this generates the next PDF (while not producing a .bbl file):    Now, I suspect it has something to do with the Biber package, which seems to me to be the default engine. I suspect this, based on similar threads I found regarding similar issues with Biber [] [] [], and from the fact that when I either force it to run with BibTeX or run it as-is in  it seems to work.  \documentclass{article} \usepackage[backend=bibtex]{biblatex} \bibliography{justin} \begin{document}  Hello! \cite{justinB} \printbibliography  \end{document}   Producing:    [] made me suspect the error may be due to me using a 64-bit installation of MiKTeX, but this persisted in the 32-bit version as well.  Neither could I find the temporary files suggested in [] and [], which point to different folders, making me suspect that Biber might generate a new folder name with a different number in each installation. I deleted whichever folders starting with the phrase 'par-' that I found on my hard drive but non of that helped to solve the problem.  Kind help would be appreciated :)

Running the minimal example  \documentclass{article} \usepackage{filecontents} \begin{filecontents*}{\jobname.bib} @ARTICLE{example,   author  = {Other, Anthony Norman},   title   = {Some things I did},   year    = {2014},   journal = {J.~Irrep. Res.},   volume  = {1},   number  = {1},   pages   = {1-10} } \end{filecontents*} \usepackage[backend=biber]{biblatex} \addbibresource{\jobname.bib} \begin{document} Hello\cite{example}. \printbibliography \end{document}   I get the warning There were undefined references.  I have read  and know that I need to run:   LaTeX Biber LaTeX   However, my editor is only set up to run BibTeX. How do I go about setting up my editor/IDE to be able to run Biber, and how do I run the LaTeX/Biber/LaTeX cycle?  Answers (sorted alphabetically by editor name)                    Answer guidelines   Each answer should be for one editor. If the editor is cross-platform, if possible give a single answer with notes covering the minor platform variations. Please edit the question to include new answers in the 'link list' Each answer should be 'stand alone', i.e. don't say 'It's almost the same as editor Y but ...' for the editor part Instructions for 'build tools' such as arara or latexmk are welcome but should explain how to set up the editor in question as not all editors allow simple addition of arbitrary tools


I have a bounding box given in EPSG:4326 and I want to reproject it into EPSG:3035. How should I be doing it?  Here’s what I tried:  try {     CoordinateReferenceSystem sourceCRS = CRS.decode("EPSG:4326");     CoordinateReferenceSystem targetCRS = CRS.decode("EPSG:3035");     MathTransform trans4326to3035 = CRS.findMathTransform(sourceCRS, targetCRS);     ReferencedEnvelope bounds4326 = new ReferencedEnvelope(5.0, 15.0, 47.0, 55.0, sourceCRS);     Envelope bounds3035 = JTS.transform(bounds4326, trans4326to3035);     System.out.println(bounds3035); } catch (Exception e) {     e.printStackTrace(System.err); }   Result:  Env[-917569.8210525657 : 536626.7649395498, 8365819.661985753 : 9500037.05372034]   But these coordinate values are not what I expected. Cross-checking in QGIS, the values should be approximately 3900000 : 4700000, 2600000 : 3600000. This makes sense, because the center of projection of EPSG:3035 is 10°E, 52°N and the false easting/northing is 4321000/3210000, so the reprojected bounding box should be around that.  My Geotools version is 15.1.

All is in the title, with GeoTools if I do :  AxisOrder order = CRS.getAxisOrder(CRS.getAxisOrder("EPSG:4326"));   It returns EAST_NORTH (= LON_LAT), but EPSG:4326 is defined as ordering latitude first and then longitude, as stated here :   So, what is happening here ? Am I doing something wrong ?