Previous title:  Lubuntu splash screen problem bc of Nvidia driver.  I'm new to linux and getting under the hood of computers in general.  I'm doing my research but it'll take awhile for me to gain a working literacy in this respect. Please bear with me if I use incorrect terminology.  I'll try to explain what I mean clearly enough for you to infer. Ubuntu saved my hide when Windows XP crashed on me and now I'm using Lubuntu. I love the idea of open source and not being at the mercy of Windows. I use Timeshift to go about things empirically (ie undoing everything I did so I don't get in over my head and cause new problems).  With that out of the way, here's the problem:  My splash screen at boot up and shut down is broken and I'm unable to fix it. It annoys me to no end, and I'm not sure if this is indicative of other problems with my graphics card's performance. I don't know what optimal performance looks like with the card because I just got it. I'm tired of plugging in various commands into the terminal, plymouth-related or otherwise, and getting nowhere. Most of the time I get info that solves my problems but not with this.   When I use any of the Nvidia graphics card's proprietary drivers, the splash screen turns into a blue screen with a janky font that looks like it's straight out of the 80s. The logo and the dots look nasty when this happens. It doesn't freeze up or anything.  When I go back to the open source driver, I get the nice logo back.  My understanding is that I need to use the proprietary driver for 3D graphics, so I'd like to just cut the splash screen out of the bootup/shutdown process entirely.  I'd rather see a black screen for a few more seconds if I can't fix it.   How do I go about that? Is it possible?   Sorry if this has been addressed in another thread.  I'm not sure if 'disabling the splash screen' is the search that puts me on the right track.  Thanks in advance for any polite responses.

When you boot from live CD, or doing the first boot after installing Ubuntu, splash screen looks awesome. But as soon as you enable nvidia-current driver, installed with apt-get, splash screen goes all crazy.  With crazy I mean that resolution is very low, font(I assume) is very weird and it all looks like it's been broken.  This happened with 10.04 and now again with 10.10.  How do I fix splash screen after enabling nvidia drivers?


There are basically two types of charged black holes,  Reissner–Nordström, and Kerr–Newman.     Next, Hawking radiation itself is mostly electromagnetic. The numerous popular articles which say that Hawking radiation is particle/anti-particle pairs in which one of each pair gets swallowed by the black hole are misleading. Hawking radiation is almost entirely electromagnetic radiation---that is, photons. You can still use the language of particle/anti-particle, but it is a bit misleading.     This answer claims that Hawking radiation is just photons. Photons are EM neutral.  Now basically there are different interpretations of Hawking radiation, but what they mainly say is that the evaporation itself does not come from the black hole itself (nothing can escape the black hole), but from near outside the horizon.     Hawking radiation comes from the horizon, not from the black hole itself   If you are worrying if your hypothetical black hole completely evaporates, i.e. no more horizon, it means that the electrons will just disperse due to the electrostatic repulsion, (once the body stops being a black hole).       Now these answers claim that BHs evaporate in a way that their leftovers are basically charged particles, that is, the charge that the BH did not evaporate stays during evaporation, until the BH's mass is not enough to create a event horizon anymore, and the BH ceases to exist anymore, and the leftover electrons just disperse.  Based on these it might be possible that the BH evaporates just photons, EM neutral particles, thus no EM charge is really evaporated from the BH, and the BH keeps its entire charge during the whole process of evaporation. At that point, as the BH's mass reduces so that it cannot create a event horizon anymore, the leftover electrons just disperse.  Question:   Does a BH evaporate its EM charge?

Black holes evaporate (Hawking Radiation) acting as black bodies with the temperature inversely proportional to the mass.  No physical process, be it evaporation or any other "trick", can make a black hole "super-extremal", namely it can't make the square of the angular momentum or the charge too large compared to the mass. As the mass drops due to evaporation the charge and angular momentum must also drop.  Angular momentum can be shed with photons, because photons have spin and can be emitted in a non-radial direction.  Charge is trickier. There are three methods to shed charge:   Accrete oppositely charged particles. This can be stopped, hypothetically at least, by isolating the hole. Emit charged particles. There are no massless charged particles, so a temperature << 511keV strongly suppresses this positron and electron generation, so making the hole large enough should stop this. Break down the vacuum with the electric field (requires ~10^18 V/m). Again, making the hole large enough should suppress this because the electric field in the vicinity of a near-extremal charged hole scales as 1/M.   If all three of these are suppressed, we have a new candidate for the longest lived objects possible! So will a large enough black hole evaporate itself toward extremity after which there will be essentially zero Hawking radiation?


$K$ is an algebraically closed field.   The coordinate ring is isomorphic to $K[t^2,t^3]$, whose Krull dimension is of at most $2$(by an hint in the exercise without proof), but how to show it’s exactly $1$ ?

Consider $K$ field and consider the ring $R=K[X^2,X^3]\subset K[X]$. It is clear that $R$ is not a Dedekind domain, since with the element $X$ one immediately see that it is not integrally closed. But $R$ is a Noetherian domain and every non trivial prime ideal is maximal. I have a proof for the last two part, but it is a bit heavy and maybe someone can help me finding a better proof! Thanks in advance!


What would most Americans call this: A pram, a stroller, or a baby carriage? Or something else?

What is the difference between a 'pram', a 'pushchair', and a 'buggy'?  According to Google:         pram: a four-wheeled carriage for a baby, pushed by a person on foot   pushchair: a folding chair on wheels, in which a baby or young child can be pushed along   buggy: a light pushchair with a soft seat that allows the chair to be collapsed inwards      It appears from the above definitions that a pram has four wheels (so those with three wheels should not be called prams?), while a buggy is a light pushchair (how light?).  I tend to think that a pushchair is the light one with four small wheels, while a pram is the heavier one with bigger wheels. But if a buggy is a 'light pushchair', how could it be that I have heard people calling what I think is a pram, a buggy.  Or can all these terms actually be used interchangeably?


This is question 1.6 from Humphrey's "Introduction to Lie Algebras and Representation Theory":     Suppose $x \in \mathfrak{gl}(n,\mathrm{F})$ has $n$ distinct eigenvalues $a_1,\ldots,a_n$. The eigenvalues of the adjoint representation $\mathrm{ad}(x)$ are then precisely the $n^2$ scalars $a_i - a_j$ for $1\leq i,j \leq n$, which of course need not to be distinct.    How do I go on proving this? Any help will be much appreciated

Let $x\in \operatorname{gl}(n,F)$ have $n$ distinct eigenvalues $a_1,\ldots,a_n$ in $F$. Prove that the eigenvalues of $\text{ad }x$ are precisely the $n^2$ scalars $a_i-a_j$ ($1\leq i,j\leq n$), which of course need not be distinct.   So we can represent $x$ by an $n\times n$ matrix $X$. We have $Xv_1=a_1v_1,\ldots, Xv_n=a_nv_n$ for eigenvectors $v_1,\ldots,v_n$.   Now, $\operatorname{ad}x$ takes $y\in \operatorname{gl}(n,F)$ to $xy-yx$. I need to show that some $y$ is taken to a scalar multiple of itself, where that scalar is $a_i-a_j$. What could be that $y$?


I have been playing around with the /etc/asterisk directory, installing the related pacakge (asterisk-config), removing it, removing the directory manually (just playing around to get the configuration synced to my configuration repo). Now I just want to reinstall the official package, so I do:  root@tethys:/etc# apt-get install asterisk-config root@tethys:/etc# tree asterisk/ asterisk/ └── manager.d   What?! Empty?!? Have I installed it?  root@tethys:/etc# dpkg --get-selections | grep asterisk asterisk                                        install asterisk-config                                 install asterisk-core-sounds-en                         install asterisk-core-sounds-en-gsm                     install asterisk-modules                                install asterisk-moh-opsound-gsm                        install asterisk-voicemail                              install   Indeed! Let me check the contents of the package:  root@tethys:/etc# dpkg -L asterisk-config ... /etc /etc/asterisk /etc/asterisk/res_snmp.conf /etc/asterisk/dbsep.conf /etc/asterisk/cel_custom.conf /etc/asterisk/cel.conf /etc/asterisk/meetme.conf /etc/asterisk/jingle.conf /etc/asterisk/queuerules.conf ...   So, what have I done that the package will get installed, but the contents are nowhere to be seen?  And, more importantly, how can I force the contents to be installed, no matter what I have done before?

I've occasionally lost my config file "/etc/mysql/my.cnf", and want to restore it. The file belongs to package mysql-common which is needed for some vital functionality so I can't just purge && install it: the dependencies would be also uninstalled (or if I can ignore them temporarily, they won't be working).  Is there a way to restore the config file from a package without un-ar-ing the package file?  dpkg-reconfigure mysql-common did not restore it.


I am new to Java and I thought I'd do some practice on my own with Scanners and Boolean. My problem is that when I run the code below, the program doesn't output anything that is within the if or else statements.   My question is: how to I make the code print out the output within the if and else statements?  The code is:   import java.util.Scanner; public class ScannerPractice {     public static void main(String[] args)     {         System.out.println("\tHello!");         System.out.println("\tPlease enter you're name.");          Scanner input= new Scanner(System.in);         String name;         name= input.next();          System.out.println("\tYour name is " + name + "?"  );          String yn;         yn= input.next();          if (yn=="yes")          {             System.out.println("\tThats a good name");         }         else if (yn=="no")         {             System.out.println("\tWhy did you lie to me?");             input.next();             System.out.println("\tI don't think I can forgive you\n\tGoodbye forever!");         }     } }   Thank you in advance.

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?


Deleted files can be recovered using recovery programs, is there any way to completely remove the files?

Is there a way to make sure that a deleted file can not be recovered?   As you know, deleting a file by pressing shift-del or using trash doesn't mean that file is gone forever. It resides somewhere in the computer.  In day to day life, law enforcement or thieves use recovery programs to reveal our private data or something else.   They can recover all data that resides on hard disk, in RAM, and even USB.  To protect us from these people, what should one do? Which program should one use?  Note: I don't want an answer like first use a recovery program then erase that file with shred. With just one program, I want to erase all unused/deleted files on my computer.


In the BBC website  a person gives some examples of the phrase "clean up one's act" and one example is:     I used to drink a lot of alcohol but when I got ill, I decided to clean up my act and now I only drink cola!   My question is: is it correct to use only before the verb it modifies?  Generally we should place “only" next to the noun, subject, verb, or phrase we're trying to modify.  So, I think it should be like I drink only cola. Am I right?  And is the sentence I drink cola only right grammatically?  I saw in many shopping malls the price was written as 1000₹ only etc. Is it right to say like this? Please explain to me the grammar relative to this.

I only teach you.   I teach only you.   I teach you only.      I think that all the sentences have same meaning, but my teacher says that they are different from each other.  I think that the expressions are different but their meaning are same.  Can you help me understand the meaning of each sentence?


I have to install Windows 8.1 on a new laptop and it works O.K. I installed Ubuntu on the same lap and also works O.K.  There is only one problem: Ubuntu can't mount the windows partitions and an error appears for each one of them. Every time I turn on the lap, I have to press "S" to skip mounting those partitions. I tried with config-ntfs to mount / unmount those partition, but it didn't work.  Config-ntfs has disabled undo option. I have experience with windows, but it's the second time I install Ubuntu. Windows 7 and Ubuntu work perfect on this laptop !! How can I fix the problem ?

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


Let $d = \gcd(a,b)$. If $a = da'$ and $b = db'$, show that $\gcd(a',b')=1$.   So far I concluded that $d$ divides both $a$ and $b$, and their remainders are zero. I don't know what to do next, someone please help me. Thank you.

Say $a$ and $b$ are integers. $\gcd(a,b)$ is then $d$. Now if $a$ equals $dm$ for some integer $m$ and b equals $dn$ for some integer n, how come the gcd of this m and n is always 1?


I have installed drupal 8.0.2 on my hosting for testing purposes. I am using Zircon template and installed TB Mega Menu 8.x-1.0-alpha1. After installation, on page: admin/structure/tb-megamenu, when I click any of button, I get the following error:  The website encountered an unexpected error. Please try again later.  by searching google, I came accross with a solution:   But as a new to drupal and environment, I do not know how to do it. I have never tried patching before and most importantly it is the solution for the case.  If patching is the solution, which program should I use, how can I accomplish this step by step?

I downloaded a patch file from mailhandler module and need to apply the changes in order to fix the problem of pop3 accounts not deleting emails after download (import).  How do I install it?


It is from Milne's notes.   I think since $[\Bbb F_{p^n}:\Bbb F_{p^m}]=[\Bbb F_{p^n}:\Bbb F_p]/[\Bbb F_{p^m}:\Bbb F_p]=n/m$. If we have such a subfield, we must have $m$ divides  $n$.  But I am not able to see that if $m$ divides $n$, then we always have such a subextension.  So may I please ask how can I do it. And how to see if there is some subextensions which are isomorphic? Thanks!

We know that if a finite field $F$ has characteristic $p$ (prime), then $F$ has cardinality $p^r$ where $r = [F:\mathbb{F}_p]$.   I'm now trying to say something about the possible cardinalities of subfields of $F$. I can see that there is a subfield of cardinality $p^s$ for each $s$ that divides $r$, given by the fixed field of the group generated by $\phi^s$, where $\phi$ is the Frobenius automorphism.  Now suppose $K$ is a subfield of $F$. Then (since both are additive groups), Lagrange gives us that $|K|$ divides $|F|$, so $|K| = p^t$ for some $1 \leq t \leq r $ (alternatively, $K$ contains $\mathbb{F}_p$ and so is a vector space over $\mathbb{F}_p$ and is thus isomorphic to $\mathbb{F}_p^t$, where $t = [K:\mathbb{F}_p]$). By considering the multiplicative group of units of $K$ and $F$ respectively, we get that $ p^t - 1$ divides $p^r -1$. I want to make the leap to $t|r$, but I'm failing to see why this needs to be true. Any help would be appreciated.


Consider $N$ items, and $N_1$ "hot items". We then select items, without replacement, until we got $n$ "hot items" ( $1\le n \le N_1 $, $n$ being a constant). Let $X$ be a random variable which represents the number of trials needed( to get the $n$ "hot items"). I need to calculate the Mean and the Variance of the variable.  So far i got this:   $$P[X=k] =\frac{ {N_1 \choose n}{N-N_1 \choose k-n}  }{N \choose k}$$ So, the minimum extractions would be $n$ ( when i select all of the "hot items") and the maximum extractions would be $N-N_1+n$ ( i select all of the "non-hot-items" and then the $n$ "hot-items"). Kind of a hypergeometric distribution. I said kind of because it's not exactly the hypergeometric distribution. Random variable X represents the number of getting n "hot items" where n is constant, not k= 1,2... But when i need to calculate the Mean of $X$, i got:  $$E[X]=\sum_{k=n}^{N-N_1+n} {k\frac{ {N_1 \choose n}{N-N_1 \choose k-n}  }{N \choose k}}$$  where I kinda get lost to it. Any idea how to solve this or i'm wrong on this?

I need clarified and detailed derivation of mean and variance of a hyper-geometric distribution.   If a box contains $N$ balls, $a$ of them are black and $N-a$ are white, and $n$ number of balls are drawn at random without replacement , then the probability of getting $x$ black balls (and obviously $n-x$ white balls) is given by the following p.m.f.  The p.m.f is $$f(x) =\frac{(_{a}C_x) \cdot (_{N-a}C_{n-x})}{_{N}C_n}  $$  The mean is given by: $$ \mu = E(x) = np = na/N$$ and, variance $$ \sigma^2 = E(x^2)+E(x)^2 = \frac{na(N-a)(N-n)}{N^2(N^2-1)} = npq \left[\frac{N-n}{N-1}\right] $$  where $$ q = 1-p = (N-a)/N$$  I want the step by step procedure to derive the mean and variance. Thank you.


I just installed Kubuntu 20.04.1 to a dual-boot partition on my Macbook Pro (late 2012). On the live usb, I could see my usual WiFi network, and connected to it. After the install, I could still see the WiFi connection in my system settings (listed as 'never used'), but I couldn't connect to WiFi. At that point, I removed the connection with the minus button, trying to get things working. Even though I checked "install third party software" in the installation settings, I figured it was a broadcom issue, and after installing the firmware-b43-installer package, I can connect to WiFi again (hooray!). Unfortunately, now I can see all the local networks except my usual WiFi network (the same one I removed earlier with the minus button, when the firmware was missing). How do I get it back? I tried to enter the information manually (from the network settings panel on a separate computer running Kubuntu 20.04.1, which can successfully connect to the network in question), but the new install still won't connect. At this point I am out of ideas, and I would sure appreciate any help you can offer, thank you for reading!

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


How can i check if user is logged in for the first time on site?  If it is, i want to show him a message...  Can someone help me?  Thank you!

I'm overriding hook_user_login to redirect users to a specific page when they log in. The problem is I'm using the verification email setting on registration which requires the user to set their password on first login, but I redirect them so some users aren't able to login the 2nd time to the site.  Is there something I can check in hook_user_login that will tell me if this is the first time the user has logged into the site?


In my network the users can acces with the administrative share C$ to my computer because they are admin users, is possible to block some computers or users?  I tried to change some options with firewall but I couldn't get.

We have a restricted Windows 7 computer that hides and prevents non-admin users from accessing the C Drive using the following policies:       However, they are able to circumvent this by typing the following into Explorer: \\localhost\C$  How can I disable this path but allow other UNC paths. For example they are allowed to access a shared folder on a different computer. eg. \\192.168.2.1\SharedTransfer  Note: Simply Enabling the Group Policy: Remove Run menu from Start Menu will not work as this blocks all UNC paths.  Update  The user, called Site User, is not a member of the Administrator group directly or indirectly. It is only a member of the group Users.  Accessed the following from: Control Panel\All Control Panel Items\Administrative Tools\Computer Management (Local) > System Tools > Local Users and Groups   Local Users and Groups  - Groups       - Administators              - Administrator              - Service User (our admin user)       - Users              - NT AUTHORITY\Auntenticated Users (S-1-5-11)              - NT AUTHORITY\INTERACTIVE (S-1-5-4)              - Site User (user account in question)


Suppose I have an immutable String class as follows:  #include <iostream> #include <string>  class String { public:     explicit String(const char *Value) : Size(std::strlen(Value)), Value(new char[Size + 1])     {         std::memcpy(this->Value, Value, Size + 1);         std::cout << Value << ", novice." << Size << std::endl;     }     template <typename T, std::size_t N> String(const T (&Value)[N]) : Size(N - 1), Value(new char[N])     {         std::memcpy(this->Value, Value, N);         std::cout << Value << ", expert." << Size << std::endl;     }     ~String()     {         delete[] Value;     } private:     const std::size_t Size;     char *Value; };  void main() {     auto &s = "Welcome to C++";     String string = s;     String str {s};     String st(s);     return; }   I want to know the role explicit plays and how the initialization syntax makes a difference when the constructor overload is chosen.    I understand that for str and st, I am explicitly calling the constructor that takes a pointer to const char, so they print out:  Welcome to C++, novice. Welcome to C++, novice.   But I don't understand why for string  Welcome to C++, expert.   is printed out. Please clarify how the overload is being selected.

What does the explicit keyword mean in C++?


I would like to know how many episodes of Naruto Shippuden are dubbed because I've only seen about 388 in all my anime streaming websites?

I am watching Naruto and I am currently on episode 164. How many episodes of Shippuden do they have dubbed, and are they still dubbing it?


Let $M_1 \to M_2 \to M_3 \to 0$ be a sequence of homomorphisms of $A$-modules. Is this sequence exact if and only if the induced sequence of abelian groups$$0 \to \text{Hom}_A(M_3, N) \to \text{Hom}_A(M_2, N) \to \text{Hom}_A(M_1, N)$$is exact for every $A$-module $N$?

The following is the first part of Proposition 2.9 in "Introduction to Commutative Algebra" by Atiyah & Macdonald.     Let $A$ be a commutative ring with $1$. Let $$M' \overset{u}{\longrightarrow}M\overset{v}{\longrightarrow}M''\longrightarrow  0\tag{1} $$ be sequence of $A$-modules and homomorphisms. Then the sequence (1) is exact if and only if for all $A$-modules $N$, the   sequence  $$0\longrightarrow \operatorname{Hom}(M'', N)  \overset{\overline{v}}{\longrightarrow}\operatorname{Hom}(M,  N)\overset{\overline{u}}{\longrightarrow}\operatorname{Hom}(M', N)  \tag{2} $$ is exact.   Here, $\overline{v}$ is the map defined by $\overline{v}(f)=f\circ v$ for every $f\in\operatorname{Hom}(M'', N)$ and $\overline{u}$ is defined likewise.   The proof one of direction, namely $(2)\Rightarrow (1)$ is given in the book, which I am having some trouble understanding. So assuming (2) is exact sequence, the authors remark that "since $\overline{v}$ is injective for all $N$, it follows that $v$ is surjective". Could someone explain why this follows?  Given that $\overline{v}$ is injective, we know that whenever $f(v(x))=g(v(x))$ for all $x\in M$, we have $f=g$. I am not sure how we conclude from this surjectivity of $v$.  Thanks!


I have mass effect 1 on the Xbox 360, recently got myself a high end gaming PC and have been looking at the three game collection.  Have been told that the second one is much better than the first, question is:  Can i skip playing number 1 and just go straight to 2? Is there a major plot line etc that carries over and I will be sitting there scratching my head? Generally speaking I like to play a game from the start, but after six attempts on the Xbox I hate it. Is it different on the PC?  I know 2 - 3 the save games can carry over?

I have never played Mass Effect, but I hear that Mass Effect 2 is great.  Do I need to play the first to understand the second?  Will I be lost?


We know that Owl magic can get around even the most powerful spells, and owls will deliver a letter to its intended recipient, even if the sender gives very little details on who they even are. Hedwig was even able to find "Snuffles" correctly despite Harry not even telling her who "Snuffles" actually was. She just delivered her letter, as a good owl should.  Given that, I was wondering about the viability of Voldemort using owls to find the order. I know it's "not his style" or whatever, but generally authors at least give some reason as to why such an obvious and simple plan wouldn't have worked.  So my question is this: Given what we know about Owl magic, would Voldemort have been able to get a parliament* of owls and say to them:  "Go and find the members of the Order of the Phoenix."  Then follow them to victory?  I don't imagine they'd even have to go very far for the first one either, because one of the owls would of course just fly about 10 feet and land in front of Snape.  Also, just to clarify, this is not a question about what Voldemort would or (probably) should have done, it's just whether or not he could.  *Yes, the collective noun for owls is called a "Parliament".

Harry, before the Triwizard Tournament, was able to send owls to Sirius when he was in hiding (not at Grimmauld Place) just by telling them "just find him, will you?", and the owl would come back a few days later with an answer. This doesn't happen with Hedwig only, because, if I recall correctly, he uses school owls as well.  If finding Sirius was as easy as telling an owl "find him", and a 13-year-old wizard could do it, how come the Ministry had no clue as to where he was? They could've sent an owl with a summons and followed it from a distance.  Two theories, neither mentioned in the book, and both a bit unlikely:   He was living as a dog and -hopefully- the Ministry would not be able to recognize him. Unlikely because the owl would have got there anyway, so they would have guessed the dog was Sirius in disguise, not necessarily as an animagus, but maybe he could perform human-animal transfiguration (remember he was brilliant at school).. Kingsley Shacklebolt was already in charge of the hunt and Dumbledore told him Sirius was innocent and all that. Then, Kingsley would have prevented the Ministry from using any method that could've actually worked. Unlikely because they could've used owls before Dumbledore's tip, when Kingsley didn't know Sirius was innocent, and also because Kingsley was quite powerful and had the support of Crouch and others at the Ministry, so if he was in charge, they would probably have succeeded.   Your thoughts?


At the beginning of my script I have this line:  Color[] oldColor;   Later I want to fill it with elements so in a function I wrote:  for (int i = 0; i < targets.Length; i++)         oldColor[i] = targets[i].color;   However, the first line is underlined in green and it says that I can't assign a value except from its default value (which is null). Also the line below the for loop (where it should copy the values from one array to the other) gives me NullReferenceException when I run it in Unity.  'targets' is defined as  SpriteRenderer[] targets;   All of its elements are assigned via the Inspector.  I don't understand what happens. Why doesn't it assign the variables?

Probably a really simple one this - I'm starting out with C# and need to add values to an array, for example:  int[] terms;  for(int runs = 0; runs < 400; runs++) {     terms[] = runs; }   For those who have used PHP, here's what I'm trying to do in C#:  $arr = array(); for ($i = 0; $i < 10; $i++) {     $arr[] = $i; }


Is it possible to be part of more than one anti-bioterrorism organization [BSA,D.S.O,TerraSave]? And is there a in universe example?

What is the difference between the anti-bioterrorism organizations in the resident evil universe [BSA,D.S.O,TerraSave]?


For any integers $a, b$, let $N_{a,b}$ denote the number of positive integers $x<1000$ satisfying $x\equiv a\pmod{27}$ and $x\equiv b\pmod{37}$. Then find $N_{a,b}$.    progress:  $x\equiv a\pmod{27}$ and $x\equiv b\pmod{37}$ implies $x=27m+a$ and $x=37n+b$ for some integers $m,n$. For common sosultion, $27m+a=37n+b\implies 27m-37n=b-a$. Now $\gcd(27,37)=1$ sow there exists integers $u,v$ such that $27u+37v=1$. Is it possible to solve using this relation ? Thank u in advance

For any integer $a,b$ let $N_{a,b}$ denote the number of positive integer $x<1000$ satisfying $x= a \mod 27$ and $x=b \mod 37$. Then which of them is correct         there exist $a,b$ such that $N_{a,b} =0$    for all $a,b$, $N_{a,b}=1$   for all $a,b$, $N_{a,b}>1$   there exist $a,b$ such that $N_{a,b}$ and  there exist $a,b$ such that $N_{a,b}=2$.      Since we know that by Chinese Remainder Theorem if $m_1, m_2, .., m_k$ are pairwise relatively prime positive integers, and if $a_1, a_2, .., a_k$ are any integers, then the  simultaneous congruences $x ≡ a_1 (mod\;m_1), x ≡ a_2 (mod\;m_2), ..., x ≡ a_k (mod\;m_k)$ have a solution, and the solution is unique modulo $m$, where  $m = m_1m_2⋅⋅⋅m_k$. Then how we will approach by acoording to this theorem. So please someone help me and explain it.


How does one go about earning the ? I have attempted looking at other answers and couldn't find much.  Is there a detailed process that could be explained please?

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


What is the reason of this error in this case?       'it' was not declared in this scope   I don't understand why I get that error, I defined it in statement of for loop..  #include <vector> #include <iostream> template<class T> void LoopFunction() {     std::vector<T> vec;     for (std::vector<T>::iterator it = vec.begin(); it != vec.end(); it++) { // **error in this line**         //....     } }

In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template <typename T, typename Tail> // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template<typename U> struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion<U> dummy;      };     template< > struct inUnion<T> {     }; }; template <typename T> // For the last node Tn. struct UnionNode<T, void> {     // ...     template<typename U> struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template< > struct inUnion<T> {     }; };   The problem I have is in the typedef Tail::inUnion<U> dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion<U> names a type and not a function?


I am developing new framework that will be released soon.  I want to use Stackoverflow as my support site. If anyone got question he should ask it here. Also I want to suggest people to use some unique tag so it will be easier for me to fallow.  Can I create new tag, without asking question for future use?

I recently saw a question about a problem (or possible bug) with some product on Stack Overflow. At first, I wanted to suggest that the asker post his question to that product's support forum.  When searching for the URL of that forum, I noticed that the product developer closed its support forums and now advises users to post all their questions on Stack Overflow instead.  Is this within the intended use cases of Stack Overflow, or is this abuse?


Is there a conventional location to store non-secret bulk files that can be accessible by multiple users?  I know that I can create a new folder (and set the right permissions) in most places in the file system.  But I'd like to follow a established convention so (a) the structure is more familiar to our new users and (b) it avoids subtle problems with certain directories that I'm not experienced enough to anticipate.  If it matters, this is a fresh Red Hat 6 install on a VM.  Users will access it through ssh, and maybe RDP or the vCloud Director.  The tarred & gziped files are 6.6GB; uncompressed is 11GB.

I am configuring a Linux work station that will be used by a small number of users (20-30). These users will belong to a small set of groups (5-10) with each user belonging to at least one group and potentially multiple groups. On the work station there are files that should only be writeable by members of a particular group. Each file is only writeable by members of one group so standard Linux permissions should work just fine. I have two questions.  Who should own the files that already exist? I was thinking either root or creating a set of dummy users corresponding to the groups. Is there a better choice that I am missing? It seems like this is unlikely a unique situation so I was hoping there was a standard convention.  The second question is where should I put the files. If I made dummy users I could create subdirectories in /home/. If root owns the files do I go with /srv/groups/ or maybe `/share/? Again is there a convention?


I'm using a C# Windows Service application where I'm having a object containing a stored procedure.  public class Sp {     public int Id { get; set; }     public string Name { get; set; }     public int IntervalMin { get; set; }     public DateTime LastRun { get; set; } }   Right now I'm using this method to check if it's time to run:  public bool TimeToRun() {     return ((IntervalMin * 60) <= (DateTime.Now - LastRun).TotalSeconds); }   The problem I have is that when the service is down during weekends and wakes up on monday TimeToRun will be true for all (considering IntervalMin isn't really high).  For example, there is one Sp with IntervalMin = 1440 (should be runned once a day), and lets says LastRun is Friday 14:00, on monday when service wakes up at 03:00 it will run, but I want it to be as close as possible to 14:00.  You have any tips of how I can build this kind of schedule? Do I need to use more properties that I set? It's no problem if it's like +/- 5 minutes or even more. TimeToRun() is checked about every each second.  LastRun is currently set to Datetime.Now, but I would like to use AddMinutes to cause no extra delays.  LastRun = LastRun.AddMinutes(IntervalMin)

I have a service written in C# (.NET 1.1) and want it to perform some cleanup actions at midnight every night. I have to keep all code contained within the service, so what's the easiest way to accomplish this? Use of Thread.Sleep() and checking for the time rolling over?


I have a specific requirement, which is when the user clicks on a button, I want to save some data then close the page.  I already did the saving function,  but I don't know what should I do to make the close option.  I mean that after saving, the page should automatically close  how can I achieve that please?  I am using asp.net with windows server 2003 on IE 8

What is the best way to close an ASPX page from the code-behind?    I have a button event handler that I want to close the page after the user has clicked an ASP.NET button on the page.  I have tried to programmatically add a JavaScript method that contains a window.close() command to the OnClientClick event to close the page but it does not work.  The button is also a asp:AsyncPostBoskTrigger for an AJAX Update Panel.  The application uses .NET Framework 3.5.


Are there any papers/books/studies on the ramifications of a theoretical world of unrestrained truth, meaning no secrets? A part of the motivation for this question is the fictional show, Code Geass, where a character has the aim of utilizing supernatural forces to rebuild the world with lacking in secrets. It got me thinking about what such a world would actually be like, but I'm having a hard time comprehending it. Similarly, are there any sources that study the necessity of secrets in our existing world? For example: States (defined as entities that have a monopoly of violence over a certain area and group of people) have secrets which are necessary for their continued existence and security, corporations have trade secrets, and of course individuals have secrets.    Some speculation is available at the following thread but no specific sources were given:

In a Bollywood movie Pk, a man comes from a planet where lying is not possible as all the thoughts/knowledge is transferable via human contact. Due to which they do not have to lie about anything or hide anything from each other.  Say, such a society plausible with technology, if we decide to abandon the privacy as we know today. All the recorded data (written, spoken, recorded videos etc.) and thought (via neuralink) is accessible to everyone, everywhere.  Basic idea behind the question is, people worry about data being accumulated at one place (entity or government) and being used against them or to deceive them. If everything is accessible/known to everyone of about anyone and anything, what does privacy mean in this case?


I broke open a dead LED night light before discarding it, and found this circuit:         – Schematic created using   I'm wondering how it works.  The diode bridge (actually in one package) and the low pass filters for the DC power supply seem fairly clear, but I'm puzzling over the arrangement of the initial capacitor and resistor.  My guess is that the capacitor and the rest of the circuit (bridge and right of it) forms some sort of voltage divider, sized to give the right voltage to the LED; I could imagine the need for a bleeder resistor, but I don't see how R1 does that, quite.  Any insights?  Certainly a minimal AC-DC power supply!

I saw a battery charger that converts 220V AC to 6V DC without a transformer.   Now I am wondering why many (if not all) power adapters are using a transformer, is it about efficiency or about drifting over time?  Update: This circuit is inside of this torch


One of my friend said that Ubuntu is Virus free I don't know whether it is true or not plz answer guyz I am new to this Community....

I thought that there was no need to scan for viruses either in Ubuntu or any Linux distros until I found virus scanner packages clamtk and klamav in Ubuntu software center yesterday.  This leads to the following questions:   How do viruses differ between Linux and Windows? How do the strategies for protection differ between Linux and Windows? Should a virus scanner package be installed on my system? If so, which would be a better option?


I have booked a (return) ticket from Boston to New Delhi. In this flight, I'll be carrying two 23 kg bags. However, My destination is Kolkata. So, I'll be buying another (return) ticket from New Delhi to Kolkata, which is a domestic flight.  But most of the domestic flights in India does not allow two check-in bags. How do I manage to transfer the extra 23 kg bag?  I have checked with Jet Airways. They are saying that after the allowance of free check-in bag (23 kg with their US-payment site), I have to pay INR 300-500/kg. This will cost me huge for another 23 kg.  For Air India, they also do the same on the weight-basis, not on the piece-basis.  Any suggestions from the experienced people?

I'm planning to travel to India from an international destination, and leaving back to the same international destination. My airline allows me to check two bags weighing 50 pounds each, and I plan to make full use of this allowance.  However, when I was booking my ticket, I found that the ticket price to my final destination in India is significantly more expensive than booking a ticket to a major hub airport (e.g. DEL, BOM, etc.) and a separate domestic ticket to my intended destination. I'm aware that if I book a ticket straight through to my final destination, I can carry the full allowance all the way through. However, I've searched around and found that if I book a domestic flight on a separate ticket, I'll only get a baggage allowance of around 15 kilograms (by weight).  As I plan to carry around 45 kilograms of baggage, which is significantly more than the 15 kilograms permitted by most airlines I've checked, it seems like I'll have to spend a lot of money in excess baggage fees. Is there a way I can transport the bags more cheaply than paying those fees, or booking a through ticket, which will probably add hundreds of dollars to the ticket price? Is there a service where I can get the baggage shipped cheaply? Or should I book a train ticket instead?


HTTP: The Definitive Guide says     An origin server that isn’t virtually hosted, and doesn’t allow   resources to differ by the requested host, may ignore the Host header   field value. But any origin server that does differentiate resources   based on the host must use the following rules for determining the   requested resource on an HTTP/1.1 request:         If the URL in the HTTP request message is absolute (i.e., contains a scheme and host component), the value in the Host header is ignored   in favor of the URL.   If the URL in the HTTP request message doesn’t have a host, and the request contains a Host header, the value of the host/port is obtained   from the Host header.   If no valid host can be determined through Steps 1 or 2, a 400 Bad Response response is returned to the client.      Where is "the URL in the HTTP request message"?  Is it the one in the request line (in the first line in a HTTP request, after method such as GET)?  Thanks.

The following quote from  assumes "the URL" comes from somewhere and uses it to restrict the Host header. Where does "the URL" come from? Is it from the first line of a HTTP request (e.g. after GET), or from the input to a web client (e.g. an argument to curl, or the input in the address bar of a web browser)? Thanks.     The Host header specifies the Internet host and port number for the   resource being requested, as obtained from the original URL:  Host = "Host" ":" host [ ":" port ]       In particular:      • If the Host header does not contain a port, the default port for the   scheme is assumed.      • If the URL contains an IP address, the Host header should contain   the same address.      • If the URL contains a hostname, the Host header must contain the   same name.      • If the URL contains a hostname, the Host header should not contain   the IP address equivalent to the URL’s hostname, because this will   break virtually hosted servers, which layer multiple virtual sites   over a single IP address.      • If the URL contains a hostname, the Host header should not contain   another alias for this hostname, because this also will break   virtually hosted servers.


In the following statement there's the usage of $F_{\sigma}$ and $G_{\delta}$  Suppose $X$ is a locally compact, $\sigma$-compact Hausdorff space. If $\cal{M}$ and $\mu$ are as described in the statement of theorem 2.14, the $\cal{M}$ and $\mu$ have the following properties:  If $E \in \cal{M}$, there's a closed set $F$ and an open set $V$ such that $F \subset E \subset V$ and $\mu(V - F) < \epsilon$ $\mu$ is a regular Borel measure on $X$ If $E \in \cal{M}$, there're sets $A$ and $B$ such that $A$ is an $F_{\sigma}$, $B$ is a $G_{\delta}$, $A \subset E \subset B$, and $\mu(B - A) = 0$.   I cannot find in the previous sections any definition of $F_{\sigma}$ and $G_{\delta}$. Can anyone tell me the used definitons? or where to find them.

From Rudin book  $\bf 2.17\ $ Theorem $\ $ Suppose $X$ is a locally compact, $\sigma$-compact Hausdorff space. If $\frak M$ and $\mu$ are as described in the statement of Theorem $\it 2.14$, then $\frak M$ and $\mu$ have the following properties: $(a)\ \ $ If $E\in\frak M$ and $\epsilon>0$, there is a closed set $F$ and an open set $V$ such that $F\subset E\subset V$ and $\mu(V-F)<\epsilon$. $(b)\ \ $ $\mu$ is a regular Borel measure on $X$. $(c)\ \ $ If $E\in\frak M$, there are sets $A$ and $B$ such that $A$ is an $F_\sigma$, $B$ is a $G_\delta$, $A\subset E\subset B$, and $\mu(B-A)=0.$  My doubt: In $(c)$ it is written that  that $A$ is an $F_\sigma$ and $B$ is a $G_{\delta}$ My confusion is about symbolic meaning what  is the  meaning of $F_\sigma$ and $G_\delta?$


I have got a problem with two crontabs that execute some operations on my website: the first one run a command every 3 minutes and the second one at 5am in this way:   m    h  dom mon dow command 0    5  *   *   *   command1 */3  *  *   *   *   command2   I suppose that works correctly and my website confirms it.  The problem is when this crontab is executed, in fact the first crontab runs at 3am and not a 5am (there aren't problem of local time).  I can't undestand where is the problem.  Thank you

This is a  about using cron & crontab.   You have been directed here because the community is fairly sure that the answer to your question can be found below. If your question is not answered below then the answers will help you gather information that will help the community help you. This information should be edited into your original question.  The answer for 'Why is my crontab not working, and how can I troubleshoot it?' can be seen below.  This addresses the cron system with the crontab highlighted.


Where is the mistake? $$-1=(-1)^{2/2}=\left(\left (-1\right)\displaystyle ^2\right)^{1/2}=1^{1/2}=\sqrt 1=1$$

I know there must be something unmathematical in the following but I don't know where it is: \begin{align} \sqrt{-1} &= i \\\\\ \frac1{\sqrt{-1}} &= \frac1i \\\\  \frac{\sqrt1}{\sqrt{-1}} &= \frac1i \\\\  \sqrt{\frac1{-1}} &= \frac1i \\\\  \sqrt{\frac{-1}1} &= \frac1i \\\\  \sqrt{-1} &= \frac1i \\\\  i &= \frac1i \\\\  i^2 &= 1 \\\\  -1 &= 1 \quad !!? \end{align}


The vertex-first parallel projection of the tesseract into three-dimensional space has a rhombic dodecahedral envelope. What is the four-dimensional projection of the five-cube? By analogy, its envelope should be a four-dimensional polytope that dissects into 5 congruent "rhombic" tesseracts in two possible ways.  What's the name of this object?

I was wondering what people call a certain type of shape. It is the shape formed by an orthogonal projection of a hypercube along one of its longest diagonals.  In other words, fill in the missing entries:  n-simplex : Triangle ->      Tetrahedon        ->  5-cell    ...      n-cube   :  Square  ->         Cube           -> Tesseract  ...      ?      :  Hexagon -> Rhomibic Dodecahedron  ->     ?      ...   IMPORTANT: I'm looking for the name of the class of shapes, not just the 4D analogue.


Let $(x_n)$ be a sequence in $\mathbb{R}$. Show that if $(2x_{n+1}-x_n)$ converges to $x$, then $(x_n)$ converges to $x$.  We don't know if the sequence $(x_n)$ is a convergent sequence or a cauchy sequence. If we are able to prove any one, then the problem is simple. Please provide any clue on how to go about.

If $ (x_{n})_{n \in \mathbb{N}} $ is a sequence in $ \mathbb{R} $ and $ \displaystyle \lim_{n \to \infty} (2 x_{n + 1} - x_{n}) = x $, then is it necessarily true that $$ \lim_{n \to \infty} x_{n} = x? $$  Could anyone kindly offer suggestions on how to approach this problem? Thanks!


I'm making an algorithm to factor a fairly large number and it's not working. I know that factoring large numbers isn't a great task for a computer, but the problem I'm working on was designed to be solvable. I think the problem is the range of unsigned long long, but the sizeof function indicates that this type is big enough for my number. My program operates as if my input overflows. Furthermore, as a test, I made a short program to overflow the type and I'm perplexed by the result. Here's the test:  #include <stdio.h>  int main (void) {     unsigned long long x = 600851475143;     printf ("%d", x);     return 0; }   The value printed is -443946297. What's going on here?

#include <stdio.h> int main() {     unsigned long long int num = 285212672; //FYI: fits in 29 bits     int normalInt = 5;     printf("My number is %d bytes wide and its value is %ul. A normal number is %d.\n", sizeof(num), num, normalInt);     return 0; }   Output:  My number is 8 bytes wide and its value is 285212672l. A normal number is 0.   I assume this unexpected result is from printing the unsigned long long int. How do you printf() an unsigned long long int?


I have Ubuntu 14.04, I want to do a fresh install of 12.04 so I can play dota 2 with the steam client for linux. I have a startup usb ready with 12.04 but when I restart or turn off it goes directly to 14.04 skipping the instalation.  Entering Bios, under boot and I see that usb boot is enabled, but on the list of boot options usb is not there, my device is not listed. Same with f12.  All I need is to be able to boot from that usb, so I can do a fresh install.  I'm using lenovo g780. And im using this ISO   Thanks in advance.

I just installed a new version of Ubuntu and I want to roll it back to the previous version.  How can I do that? Is that even possible?


I have been stuck with the following problem for hours, and I was hoping someone could give me a hint to attack it. Thanks! We define a distribution as a function together with a  linear ordering on the preimage of each element of the codomain. Using exponential generating functions, we want to obtain the formula $$ {n \choose k} (n-1)_{n-k}$$ for the number of surjective distributions from a set n labelled objects to a set of k labelled places.  Particularly, I am trying to solve the problem by using the theory of species. I know that the number of surjections from a $n$-element set to a $k$-element set is $k!S(n,k)$, where $S(n,k)$ is the Stirling number of the second kind, but I don't know how to combine this with the fact that we have the linear ordering on the preimage of each element of the codomian.

It is quite easy to calculate the total number of functions from a set $X$ with $m$ elements to a set $Y$ with $n$ elements ($n^{m}$), and also the total number of injective functions ($n^{\underline{m}}$, denoting the falling factorial). But I am thinking about how to calculate the total number of surjective functions $f\colon X \twoheadrightarrow Y $.  The way I thought of doing this is as follows: firstly, since all $n$ elements of the codomain $Y$ need to be mapped to, you choose any $n$ elements from the $m$ elements of the set $X$ to be mapped one-to-one with the $n$ elements of $Y$. This results in $n!$ possible pairings. But the number of ways of choosing $n$ elements from $m$ elements is $\frac{m!}{(m-n)!\,n!}$, so the total number of ways of matching $n$ elements in $X$ to be one-to-one with the $n$ elements of $Y$ is $\frac{m!}{(m-n)!\,n!} \times n! = \frac{m!}{(m-n)!}$.  Now we have 'covered' the codomain $Y$ with $n$ elements from $X$, the remaining unpaired $m-n$ elements from $X$ can be mapped to any of the elements of $Y$, so there are $n^{m-n}$ ways of doing this. Therefore I think that the total number of surjective functions should be $\frac{m!}{(m-n)!} \, n^{m-n}$.  Is this anything like correct or have I made a major mistake here?


I'm just curious if there exists an actual guideline for when to use downvotes.  Are they used solely for questions worded poorly or with little/no research?  Are they used when you don't understand the question?    I mean, I know people will use them however they want, but I'm just curious if some sort of "best use policy" was ever covered?

I have seen a few  here on Meta Stack Exchange that cover parts of this, but they are often too local, and none of them seem to cover all the relevant scenarios.  I will break it up into multiple parts in order to make this more specific:     When should I vote on a question:   What are the qualifications for a question to be deserving of being up-voted? When shouldn't I vote up on a question? What are the things that would cause a question to need to be down-voted?   How should I go about down-voting the question (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on a question?  When should I vote on an answer:   What are the qualifications for an answer to be deserving of being up-voted? When shouldn't I vote up on an answer? What are the thing that would cause an answer to need to be down-voted?   How should I go about down-voting the answer (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on an answer?  When should I vote on a comment:   While votes on comments do not affect reputation points, it might be useful to new users to know when to up-vote them.    It seems that a full, comprehensive list of these would be invaluable to new users looking to figure out how the voting system works, but this list seems to be missing from the meta site.


I randomly decided to do all the Ronin missions first in SR2. However, a character dies in Bleeding Out, which means they won't be in the rest of the game (I assume). Would they have appeared in cutscenes or plots for other missions if I had done those missions before Bleeding Out?  To be specific:      Not Gat, who is addressed in  but Aisha.

Is there a specific order to complete SR2?      I remember playing once and Gat got killed, but then later playing against a different gang he was still there for cut-scenes.    This made me thing that I may have done something out of order.


I know that /proc gets generated on the fly, but I'm curious, if fork, evecve and process termination are guaranteed to be seen by all other processes immediately.  Obviously, the kernel knows it all, but I'd like to see explicitly stated, that the presented information is really always up to date. I could imagine the kernel might choose to minimize synchronization overhead or whatever by batching updates to some internal structures used for /proc.   This sounds improbable, but there is a problem with our code, which could be explained by this. It's misusing reading /proc for a "single instance check" (which is racy and IMHO plain wrong). When two instances get started nearly concurrently, then it obviously can happen, that each sees itself and the other instance and both complain. However, it looks like the opposite problem (no instance complains) happens to our customers.  Clarification  The  states that "For making accounting scalable, RSS related information are handled in an asynchronous manner and the value may not be very precise". Analogously the whole process list could be handled asynchronously and that's what I'd like to see clearly confuted. An   This  says that     Most (if not all) files in the /proc filesystem are special files, their content at any given moment reflect the actual OS/kernel data at that very moment, they're not files with contents periodically updated.   But it doesn't say if "most" includes what I care about, nor does it claim to be an authoritative answer.

What happens when I write cat /proc/cpuinfo. Is that a named pipe (or something else) to the OS which reads the CPU info on the fly and generate that text each time I call it?


i upgrade system from 13.04 to 13.10 then i restarted system the problem is coming ''the package lists or status file could not be parsed or opened.'' rajuramvani.

The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this?


Is there any problem in submitting a preprint to a journal while this preprint is already on arXiv with the public domain license (which was selected by mistake)? If so, how can I solve this knowing that arXiv doesn't withdraw published papers?

I am a PhD student from computer science and try to submit a paper to IEEE transactions. In addition, I also submitted it to arXiv under the CC0 license (Creative Commons Public Domain Dedication), where it was already published. This might be unacceptable for IEEE.   My question is: Can I just withdraw the current version, and resubmit it to arXiv under non-exclusive license? It seems like that there will be a record in arXiv. Will it affect my IEEE publication?


I am on the lookout for a laptop for development. There seems to be no shortage of questions addressing this issue. However, the answers to these posts seem outdated. This is the kind of question which needs to be raised time and again as the market changes. I am pretty sure that a post titled "Budget Laptop for Development - 2010 Q3" will be closed in no time and downvoted mercilessly.  Could we have some way to protect such posts? This is definitely programming related and could also lead a lot (that's understating it) of search traffic to the site. Not to mention that the best answers to such a question are to be found nowhere else but on SO.  How do we go about discussing such topics? How do we protect such discussions from being downvoted/closed/flamed?

I've seen many questions on Stack Overflow asking which devices are best for developers. This made me wonder if questions asking for hardware device recommendations (best device for programming, best device within a certain budget, etc.) are on-topic for Stack Overflow, or if they should be asked somewhere else?  For Instance check these links:         etc.


Simple question. I feel like it should have a simple answer but I can't find anything.   The documentclass book (and default multicols) stretches content so that it fills the page. Now, I want to use this content in a document of mine that is typeset with the article documentclass.   If I use book and redefine the margins I get what I want, except that it changes \sections and \subsections, which doesn't look right for a formal lab report.

I understand that I can control interline spacing in LaTeX in a number of ways. The commands like ,  ,  come in handy in controlling the interline spacing. Each has its own speciality and circumstances of usage, as we can find in these discussions (, , ).  If want to go for a ready made solution for controlling line spacing, packages like  come in quite handy (built-in commands like \onehalfspacing or \setstretch for more finer controls).  Anyway, my problem is a bit different. I have some text (both in paragraph and list mode) which I want to fill up exactly one page. To complicate the scenario, it may even contain equations and graphics. (Let us leave aside floats.)   If I want to solve the problem statically, all I will have to is to play with some value of \baselineskip (or  \setstretch) until satisfied. While this works good for most of the cases, I will have to go through the process again when I want to delete or add some texts.  Would it be possible to have a dynamic value for  \baselineskip or  \setstretch so that my text always fills up one page? (Definitely within reasonable limits.)  Another idea will be to use a number of \vfills between some pieces of texts. But I think that this technique is usable for cover pages only.  I am not putting here an MWE. I think that one is not applicable.    The problem is not a theoretical one, I am preparing some kind of handout which I want to fill-up exactly one page.


I am new to MySQL database.  So I want to know the exact SQL query to fetch Nth row. Please help me solve this issue. Thanks in advance.

I'm interested in learning some (ideally) database agnostic ways of selecting the nth row from a database table. It would also be interesting to see how this can be achieved using the native functionality of the following databases:    SQL Server MySQL PostgreSQL SQLite Oracle   I am currently doing something like the following in SQL Server 2005, but I'd be interested in seeing other's more agnostic approaches:  WITH Ordered AS ( SELECT ROW_NUMBER() OVER (ORDER BY OrderID) AS RowNumber, OrderID, OrderDate FROM Orders) SELECT * FROM Ordered WHERE RowNumber = 1000000   Credit for the above SQL:   Update: See  regarding the SQL standard. Troels, have you got any links we can cite?


I have this challenge, that i've found out that i'm not the only one in the WEB with the same issue, nevertheless, there are no solutions yet.  I'm trying to remove shortcodes from my custom post types excerpts.  here is my example:   in sidebar there's the "in the neighborhood" widget that shows images with excerpts... some are showing this issue.  Any tips?  Thanks in advance

I'm using the following function to create a custom excerpt for my homepage and categories pages so I can do it by character count and have a custom "read more". However, I have captions shortcode showing up in my excerpt.  Example: [caption id="attachment_4656" align="aligncenter" width="450"] Crispy Vegetable Tacos[/caption] Do you sometimes feel overwhelmed when trying to decide what to make for dinner? What I’ve learned from my years as a family dinner planning expert ... continue reading  I tried adding line 5 to strip out the actual shortcode code but it isn't working. Am I on the right track? I'd prefer the shortcodes not to show at all and I've used the function I've seen on the 'net but it isn't working (I'm guessing cause I'm using a custom excerpt function). Anyone want to help me out, please? function get_excerpt($count){    $permalink = get_permalink($post->ID);    $excerpt = get_the_content();    $excerpt = strip_tags($excerpt);    $excerpt = str_replace(']]>', ']]>', $excerpt);    $excerpt = substr($excerpt, 0, $count);    $excerpt = substr($excerpt, 0, strripos($excerpt, " "));    $excerpt = $excerpt.' ... continue reading ';    return $excerpt; }  The fifth line I attempted to convert from this: $content = str_replace(']]>', ']]>', $content);  TIA!


I am trying to learn drawing in latex with TikZ for simple shapes. But when I want to draw shapes in 3D or special shapes I am confused. I think there are some applications to make it easier and convert an image to latex code. Can you give me suggest for the application?

What packages do you use and recommend for creating graphics in your LaTeX documents?     As this is a community wiki post, please add your package to the accepted answer (or add a comment, and someone with >100 rep will add it to the CW answer), and include a brief description of what differentiates it from others and how it can be used (GUI drawing tool which generates code, type in raw text, or generates image for inclusion in document).   We'll eventually sort these answers under headings.


How do I include the column BY in a query? I first tried =unique(query(data_table,"SELECT D, BY"))  Then, I tried to surround it with single quotes =unique(query(data_table,"SELECT D, 'BY'"))

I'm using the following query to pull data from one sheet into another.  =query(data!B2:CL,"select B, C, D, E, F, G, H, I, J, BB, BZ, CA, BA where J = 'Industry Certification'",false)   The above query works perfectly. However, if I change 'BB' to 'BY'. I get the following error.      Error      Unable to parse query string for Function QUERY parameter 2:   PARSE_ERROR: Encountered "BY" at line 1, column 35. Was expecting one   of: "true" ... "false" ... "date" ... "timeofday" ... "datetime" ...   "timestamp" ... "min" ... "max" ... "avg" ... "count" ... "sum" ...   "no_values" ... "no_format" ... "is" ... "null" ... "year" ... "month"   ... "day" ... "hour" ... "minute" ... "second" ... "millisecond" ...   "with" ... "contains" ... "starts" ... "ends" ... "matches" ... "like"   ... "now" ... "dateDiff" ... "quarter" ... "lower" ... "upper" ...   "dayOfWeek" ... "toDate" ...  ...  ...    ...  ...  ... "(" ... "-"   ...   The value of cell 'BY' is a simple string (activities).   I'm scratching my head confused. Any help is greatly appreciated.


How to convert a known one-dimensional array into a two-dimensional array by python but without using numpy? (just using basic python language)) e.g suppose you have an one dimensional array with 100 elements, now you need to use python to transfer it into a 10x10 matrix but without using numpy. You can only use the basic python language, like for loops.

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


If $\int^x_0  f (t) dt =x+  \int^1_x  t f (t) dt$, find value of $f(1)$  solution:- $\int^x_0  f (t) dt =x+  \int^1_x  t f (t) dt$ $\int^x_0  f (t) dt =x+  \int^0_x  t f (t) dt$ +  $\int^1_0  t f (t) dt$ $\int^x_0  f (t) dt =x-  \int^x_0  t f (t) dt$ +  $\int^1_0  t f (t) dt$ $\int^x_0  f (t) dt + \int^x_0  t f (t) dt$ =$x  +  $$\int^1_0  t f (t) dt$  I think, I am not in the right track Help me to find the value of $f(1)$

My brother brought me this same question, also on this .   $$\int_{0}^{x}f(t)dt = x+\int_{x}^{1}tf(t)dt \tag{1}$$  When I try to solve it, I also did same thing. Differentiation leads to  $$f(x) = 1-xf(x)\\  f(x) = \frac{1}{1+x} \\ \int_{0}^{1}f(x) dx = \ln 2 $$  But try putting $x = 1$ in original equation $(1)$,  $$\int_{0}^{1} f(t) dt = 1$$  so what has happened? We get two contradictory results.  Is it still true that $f(1) = 1/2$? Where is the mistake?


Before updating to 20.04 my HP OfficeJet 8720 worked. After updating from 18.04 to 20.04 HP OfficeJet 8720 gets lpstat -p \printer HP-OfficeJet-Pro-8720 now printing HP-OfficeJet-Pro-8720-0.  enabled since Sat 29 May 2021 09:34:09 PM EDT     Rendering completed  but nothing is printed.

Let's assume that one has some HP printer and/or scanner and checked its support status on the corresponding page of HPLIP site - .  So one have the following information: the device Model name, Min. HPLIP Version and Driver Plug-in need.   What should one install to make Ubuntu fully support the HP printer and/or scanner?


Now a days in iOS stack exchange app I'm getting the same notification twice.      My device is iPhone 5 with iOS 9.2.1.  Stack Exchange App version is 1.4.3.7   Is this problem with my mobile?

I receive every push notification from the iOS app twice on iPhone. The second comes immediately after the first. This happens every single time.   I also have the app installed on an iPad and signed in to the same account - could this be a possible cause?   App Version: 1.4.0 Device: iPhone7,2 OS Version: Version 9.1 (Build 13B143)


I have a Roles pojo class which maps to Roles table in the database . Then i have RolesDao and it's implementation RolesDaoImpl.  i call the RolesDao using the below code in the main() method :-  RolesDao rolesDao = context.getBean( RolesDao.class);         rolesDao.getRolesList();   But i get the below error : -  Exception in thread "main" java.lang.NullPointerException     at com.rahul.spring.dao.RolesDaoImpl.getRolesList(RolesDaoImpl.java:35)   How do i resolve it ?  My RolesDaoImpl is below :-  @Component public class RolesDaoImpl  extends BaseDaoImpl implements RolesDao  {  @Autowired private OracleConfiguration dataSource; public List<Roles> getRolesList() {          String sql = "SELECT * FROM ROLES";         List<Roles> customers  = getJdbcTemplate().query(sql,                 new BeanPropertyRowMapper<Roles>(Roles.class));         return customers;         }   And my BaseDaoImpl is below       @Component     public class BaseDaoImpl {        private JdbcTemplate jdbcTemplate; //getters and setters omitted for brevity          private String packageName; public JdbcTemplate getJdbcTemplate() {         return jdbcTemplate;     }       public void setDataSource ( DataSource dataSource )     {         this.jdbcTemplate = new JdbcTemplate(dataSource);     }   And my OracleConfiguration class is   @Configuration //@ConfigurationProperties("oracle") @PropertySource("classpath:dev.properties") public class OracleConfiguration {      @Value( "${oracle.username}" )     private String username;// we can remove value injection and just use      @Value( "${oracle.password}" )     private String password;  @Value( "${oracle.url}" )     private String url;     @Value( "${oracle.driverType}" )     private String driverType;     @Bean DataSource dataSource() throws SQLException {      OracleDataSource dataSource = new OracleDataSource();     dataSource.setDriverType(driverType);     dataSource.setUser(username);     dataSource.setPassword(password);     dataSource.setURL(url);     dataSource.setImplicitCachingEnabled(true);     dataSource.setFastConnectionFailoverEnabled(true);     return dataSource; }   I am able to print/get the values from dev.properties file.

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?


For a few days now, I have wondered why my small avatar changed to some "colored blob". I've tried with different browsers, all the same. Found some related questions here at Meta:       But none of the explanations seem to match. Some facts:   I haven't changed either my image nor my mail address for years (so it shouldn't be a caching issue) while the small image resolves to a blob, the big one comes fine URL of the small: https://www.gravatar.com/avatar/e2b29bd68eb03763a0e18c691ecf9fa5?s=32&d=identicon&r=PG URL of the big: https://www.gravatar.com/avatar/e2b29bd68eb03763a0e18c691ecf9fa5?s=328&d=identicon&r=PG   you see they only differ in the s= parameter (size) you see both are using d=identicon instead of d=gravatar (trying the small URL with d=gravatar resolves to the correct image)  My profile image is set to "Gravatar", not to "Identicon"   Any way to get that fixed?

When I first signed up on a Stack Exchange site and got a profile image, it was this one (see my current user card I'm actually not sure what I look like any more):     Later, I got  and SEDE profiles, and my user image there was a different identicon. Because . I would have a picture of it, but that's the problem. ... Thanks to , I have a picture:     On those two sites, it changed from that purple one to this new one recently:   I don't know when the change happened exactly, but I KNOW I didn't change it (I don't know how to change it, otherwise I would have changed it to my main pink one).  Why did this change? Can I get my other icon back or will I be stuck with this new one?   Also, are the gravatars at Area 51 and SEDE securely generated?    After looking in my profile settings, I really confused (I am seeing my wrong avatar in more and more places since I first posted this.):        Seriously.......    What...?    (I'm using this , but be warned that they will try to IP block you after a certain number of requests to force you to pay... May look for a better alternative later.)


I had my laptop for quite some time and just can't get used to the fact that my right alt-key is next to the context-menu key. Whenever I want to do coding special-characters, a menu pops up and has me raging. Therefore, what is the most light-weight solution to map it to Alt Car (right)?  EDIT: Using Windows 7, map in all contexts.

One of my laptop's keys has fallen off. Is there any way I can remap another key to serve as that key?  I'll 'sacrifice' the other key because I never use it.


Why do medium format (digital) cameras capture better dynamic range than smaller sensor cameras?

I already understand all the theory behind how a bigger sensor leads to better control of depth of field, and lower noise. But I've yet to find a place that can explain why a bigger sensor gives you a bigger dynamic range?


Gravitational waves do not dissipate.  How significant is this accumulation of gravitational waves throughout the entire history of the universe? How much energy is that accumulation and how does that compare to the density of "dark energy"?  Could they be  one and the same?

Is the energy carried by gravitational radiation a viable candidate for $\Lambda$ / dark energy?


I actually dont need this question to be answered for university or something, it was just a discussion I had with a friend.  Does the empty set have an upper or lower bound?  Since the supremum is the minimal bound it must be $-\infty$ since  there is no element in the empty set such that it is bigger than $-\infty$. It somehow makes sense. On the other hand the infimum is $\infty$.   Can one define something like that for the empty set? Or is it just heuristic...?

Let $E$ be an empty set. Then, $\sup(E) = -\infty$ and $\inf(E)=+\infty$. I thought it is only meaningful to talk about $\inf(E)$ and $\sup(E)$ if $E$ is non-empty and bounded?   Thank you.


Why can a decimal number always be accurately represented in a Decimal datatype whereas in a Double it cannot. Does a Decimal datatype have more bits in the Mantissa? Is a Decimal datatype normalised?

What is the difference between decimal, float and double in .NET?  When would someone use one of these?


Does anyone know how to file a bug report for /etc/avahi/avahi-autoipd.action it comes in the the package avahi-autoipd but I'm not sure if this script is avahi devs or Ubuntu.  The script is called by avahi but I'm not sure if its written by them. Bug is that it tacks :avahi on to the interface name and the exceeds the 15 char limit.

I found a problem with an application on Ubuntu.   Questions :   How do I best report the issue?  What sort of information should I provide?


What is the distribution of the quadratic form $\mathbf{v}^{\top} \Sigma^{-1} \mathbf{v}$, when $\mathbf{v}$ is a multivariate normal with covariance $\Sigma$ and zero means? I suspect this is related to the . In general there is no simple closed form expression for the distribution of a quadratic form of this type. But here the quadratic matrix is constructed with the inverse covariance matrix, which I hope makes the result simple.

Given a multivariate normal distribution  $f(x) = \frac{1}{\sqrt{(2 \pi)^n|\Sigma|}} \times \exp\left( -\frac{1}{2} (x-\mu)' \Sigma^{-1} (x-\mu)\right)$  how can I prove that $ (x-\mu)' \Sigma^{-1} (x-\mu) \sim \chi^2_{p} $?


My head tells me it's a scam.  She doesn't have a smart phone so all communication is by email. She has already asked for money for air tickets then proof of money in her bank so that she can leave Russia. She now says that she won't be allowed to leave without paying off her debt.  Can someone leave Russia if they owe money to their bank, like having a mortgage?

On Travel.SE we often see questions about a person (usually a love interest) asking for money to pay for airfare, visas, permits and other expenses. For example        What general advice can be given in such situations to the person asking the question? Is it all a scam or can there be legitimate situations in which an online friend could be asking for money?


I've seen many explanations that just treat ought to as a whole which equals should. but how to explain the function/role of each word separately? for example:  I ought to go now.  which role does to act there?  where to is just part of the to-infinitive to go (as a mere infinitive marker, no meaning) if so, why to-infinitive marker is required after ought, but not after should?  to is part of the phrase ought to, if so what's its function/role at all?   I have similar questions in understanding auxiliaries like have to and used to also, so how to understand this kind of structure correctly?

have to must should ought  I found a lot of examples with explanations on using this words applying to people, but not to inanimate objects. In the case of inanimate objects, such explanations as “obligatory”, “moral correctness”, “advise” etc. does not work. What the verbs should be used in the next sentences?  The car _______  turn when the driver turns the steering wheel. The car _______ not start moving spontaneously. The (computer) program _______ solve the equation. If an error occures, the program _______ indicate a message.  I think, different variants are possible and they have different meanings.


There is a story where every one is shown to have a unique knack. For example, one man can make an ashtray-sized object vanish (but he can't bring it back). Another man's knack is to be able to transport a person/object between two cabinets. As far as I recall, this was a short story in some collection.  Thanks for the help!

I found a box of books in the attic of a new house at age 12, the summer of 1963.  It contained 2 sf anthologies.  One was Damon Knight stories.   The other one was a hard bound collection of multiple stories by multiple authors with many different themes.  The  (not Damon Knight) story I recently remembered involved a pathetic guy (with blond roots) who has been trying to seduce a beautiful non-stereotypical blond.  She demonstrates, in the last paragraph, a "trick"  that causes a fire poker to suddenly sag.  I didn't get at age 12, but when something reminded me of the scene a while back I did and started laughing out loud.  It probably would have been funniest when I was a high school sophomore, but I would like to see if I can locate the story and maybe even the anthology.  Ah, retirement.  I think the  was yellow.


Linux/Ubuntu noob here and my installation just choked with the /sbin/init error.  This is similar to this previous issue:   And this  describes the apparent solution.  I have a dual boot eepc 1001px, my partitions are a little different, fdisk -l gives me:  /dev/sda1 * ID=7 HPFS/NFFS /dev/sda2   ID=lb Hidden w95 FAT32 /dev/sda3   ID=5 Extended /dev/sda4   ID=ef EFI (FAT-12/16/32) /dev/sda5   ID=83 Linux   I'm using a bootable usb key with the netbook 10.10 version installed so I can get into Ubuntu that way for diagnostics.  I tried the sudo fsck /dev/sda5 as mentioned in the second link to attempt a repair however I get the following error:  fsck.ext4: Device or resource busy while trying to open /dev/sda5 Filesystem mounted or opened exclusively by another program?   And I've no idea what to do next :(

My friend has been using ubuntu 10.10 on vmware player for many days now. But today, it has a problem booting, so we started the ubuntu live cd to try and fix it.  Running sudo fsck /dev/sda1 (got from ) says that the device or resouce busy. So, I'm guessing the partition was not unmounted correctly on the last shutdown for some reason.  Any help on how to fix the problem would be appreciated. If you need any further information, please provide the command to get it, as we have little knowledge of that.  Thanks.


Is there any way to lock files of these types:   txt pdf docx doc   If locked, it should not be possible to edit, copy or print it.

I have a Java process that opens a file using a FileReader. How can I prevent another (Java) process from opening this file, or at least notify that second process that the file is already opened? Does this automatically make the second process get an exception if the file is open (which solves my problem) or do I have to explicitly open it in the first process with some sort of flag or argument? To clarify: I have a Java app that lists a folder and opens each file in the listing for processing it. It processes each file after the other. The processing of each file consists of reading it and doing some calculations based on the contents and it takes about 2 minutes. I also have another Java app that does the same thing but instead writes on the file. What I want is to be able to run these apps at the same time so the scenario goes like this. ReadApp lists the folder and finds files A, B, C. It opens file A and starts the reading. WriteApp lists the folder and finds files A, B, C. It opens file A, sees that is is open (by an exception or whatever way) and goes to file B. ReadApp finishes file A and continues to B. It sees that it is open and continues to C. It is crucial that WriteApp doesn't write while ReadApp is reading the same file or vice versa. They are different processes.


I created a .sty file that I used locally with a tex file.   I mean that I put the tex and the styfile on the same folder (in my documents) and call the styfile as a \usepackage{mycustomstyfile}  However I try to do the same in LyX by putting \usepackage{mycustomstyfile} in the preamble but it does not work. Someone can help me?   The LyX error message is   Undefined contorl sequence :   s        kldafjkldfjksdfjl The control sequence at the end of the top line of your error message was never \def'ed. If you have misspelled it (e.g., `\hobx'), type `I' and the correct spelling (e.g., `I\hbox'). Otherwise just continue, and I'll forget about whatever was undefined.

I know how to define a package or a class, but how do I make it available (to myself) at all times?  Say I have the package file commonstuff.sty (or myprettyclass.cls), that I want to be able to include in any .tex file I create on my computer. Where do I put it? Do I need to run some installer on it, or is it enough to keep it in a certain folder?  Note: I know I can just place it in the same folder as the .tex file, but that's not what I'm after here. I'm looking for a way to "install" the package centrally on my computer.


In notification panel, I have a notification that says "Instal/update Google Play Services" (or so).  How can I solve this problem?

I have recently installed a custom ROM and cannot find the Play Store. It seems like all apps that belong to Google are missing.  How can I install the Google Apps Package (Play Store, ...) on my Android device?


As human beings, we observe the world in which we live in three dimensions. However, it is certainly theoretically possible that more dimensions exist.  Is there any direct or indirect evidence supporting a fourth dimension?


I am wondering if there is a command one could type into The Windows Command Prompt which would cause Windows Explorer to open a folder set at the Command Prompt's current working directory?   (This is kind of the opposite problem where people want to open the Command Prompt from the folder. I.e., opposite of this: )

You open cmd and type (for example) cd C:\dragons  How can you open C:\dragons in the file explorer? Yes, you can use explorer C:\dragons, but that is kinda lame. Let's say I'm in the folder C:\dragons\Red\WhiteCrests\infants, this way just isn't convenient.  Already tried explorer dir and explorer path (both of which opens My Documents for some reason), just explorer (opens the Libraries folder), open which is undefined, explorer dirname which gives me that dirname is undefined, and probably other stuff that I can't remember.  Thanks in advance.  ...Shamelessly adding to the question with a thought I just had, how can you open a file (say C:\dragons\intro.txt) with a specified program? Like, instead of the default one (like Notepad), open it in Notepad++, without using Notepad++'s (if one exists) command line stuff. Something like:  cd C:\dragons intro.txt --Notepad++


$$\lim_{x\to0}\left({\frac{1}{x^2}}-{\frac{1}{\sin^2x}}\right)$$  Using the L'Hospital Rule I obtained the value $-1/4$, but the answer is given to be $-1/3$. I can't find the mistake. Here's what I did; please point out the mistake.  \begin{align} \lim_{x\to0}\left({\frac{1}{x^2}}-{\frac{1}{\sin^2x}}\right)&=\lim_{x\to0}\frac{(\sin x+x)(\sin x-x)}{(x\sin x)(x\sin x)} \\[1ex] &=\lim_{x\to0}\left(\frac{\sin x+x}{x\sin x}\right)\lim_{x\to0}\left(\frac{\sin x-x}{x\sin x}\right) \\[1ex] &=\lim_{x\to0}\left(\frac{\cos x+1}{\sin x+x\cos x}\right)\lim_{x\to0}\left(\frac{\cos x-1}{\sin x+x\cos x}\right) \\[1ex] &=\lim_{x\to0}\:(\cos x+1)\,\lim_{x\to0}\left(\frac{\cos x-1}{(\sin x+x\cos x)^2}\right) \\[1ex] &=\lim_{x\to0}\frac{-\sin x}{(\sin x+x\cos x)(2\cos x-x\sin x)} \\[1ex] &=-\lim_{x\to0}\left[\frac{1}{1+\cos x\left(\frac{x}{\sin x}\right)}\right]\left(\frac{1}{2\cos x-x\sin x}\right) \\[1ex] &=-\frac{1}{2}\left[\lim_{x\to0}\,\frac{1}{1+\cos x}\right] \\[1ex] &=-\frac{1}{4} \end{align}

Find the limit without the use of L'Hôpital's rule or Taylor series  $$\lim \limits_{x\rightarrow 0} \left(\frac{1}{x^2}-\frac{1}{\sin^2x}\right)$$


I was out for a meal with a few Spanish friends of mine and at one stage during the evening we all "clinked" (?) or touch our glasses together.  This is something that is usually done after someone makes a toast.  I was then asked what the term for this was in English and I didn't know.  There is a term in Spanish for this, but I am not aware of one in English.  I have asked a few people and some people have suggested "A toast" but I do not believe this is the case.  Can anyone help me with what this is called?

When beers in cans or bottles are banged together in rejoice of the company you're with, what is the action called?


My DM and I were discussing this, and he asked me to search for it/post it here. I looked around, but couldn't really find anything that discussed this issue specifically. The description of Concentration is:  Some spells require you to maintain concentration in order to keep their magic active. If you lose concentration, such a spell ends. If a spell must be maintained with concentration, that fact appears in its duration entry, and the spell specifies how long you can concentrate on it. You can end concentration at any time (no action required). Normal activity, such as moving and attacking, doesn't interfere with concentration. The following factors can break concentration: Casting another spell that requires Concentration. You lose concentration on a spell if you cast another spell that requires concentration. You can concentrate on two spells at once.  The section goes on to outline two more things that can break concentration; Taking Damage, and Dying.  It is this first one that we were discussing.  Lets say that I cast Darkness (Which has the Concentration Tag). On my next term can I cast Shatter (Which does NOT have the Concentration Tag), without ending the Darkness Spell? The wording seems to indicate that you CAN do this, But I've had several other DnD Players tell me that you can't.

Is it possible, while concentrating on one spell, to cast a different spell or cantrip that do not require concentration without losing that concentration?


The question is the following: Assume $f: \mathbb{R} \rightarrow \mathbb{R}$ is continuous, and for all $x \neq 0$, $f'(x)$ exists. If $\lim_{x \rightarrow 0} f'(x) = L$ exists, does it follow that $f'(0)$ exists?  My intuition is that this does not have to hold in general. However, I keep finding counter examples such that $f'(0)$ exists where $\lim_{x \rightarrow 0} f'(x) = L$ does not exist, which is obviously not the original question.

Let $f$ be a real-valued function continuous on $[a,b]$ and differentiable on $(a,b)$. Suppose that $\lim_{x\rightarrow a}f'(x)$ exists. Then, prove that $f$ is differentiable at $a$ and $f'(a)=\lim_{x\rightarrow a}f'(x)$.    It seems like an easy example, but a little bit tricky. I'm not sure which theorems should be used in here.    ==============================================================  Using @David Mitra's advice and @Pete L. Clark's notes I tried to solve this proof. I want to know my proof is correct or not.  By MVT, for $h>0$ and $c_h \in (a,a+h)$ $$\frac{f(a+h)-f(a)}{h}=f'(c_h)$$ and $\lim_{h \rightarrow 0^+}c_h=a$.    Then $$\lim_{h \rightarrow 0^+}\frac{f(a+h)-f(a)}{h}=\lim_{h \rightarrow 0^+}f'(c_h)=\lim_{h \rightarrow 0^+}f'(a)$$   But that's enough? I think I should show something more, but don't know what it is.


I was just listening to someone talk about how the older content is the more relevant it is seen by search engines even if it is obsolete info.  But it seems in many cases it is good to leave content in place for historical\reference reasons.  Is there a standard way (tag, meta-tag, http response code) to mark up a page as obsolete?    Or at least is there a standard way to tell the search engines that the pages are less relevant.  To be absolutely clear, I am not asking how to make the pages unavailable (for which there are clear HTTP status codes), but rather how to acknowledge that they may no longer be relevant except for historically.

Before asking my question, I'll use an example to clarify the idea.  Say that a company used to sell horses and then they turn into a sheeps business. While some of the old pages can be mapped to the new pages using a 301 redirect, because they're really related in the content and the company don't want to lose users and link juice, there are a lot of pages strictly related to horses that they want to shutdown.  What's the best practice? Is there a way to say to users and Search Engines the content you were looking for won't be available any more?  Basically a 301 redirect of the closed pages to new ones seems not so good, because you'll show a content totally unrelated to the searched one.  P.S: I'm aware that probably the best fallback is to simply map those pages to the homepage but I hope in a smarter solution.


We know “misogynist” is the word that we use for "a man who hates women”.   Do we have any single word for “a woman who hates men”?

I came across the following sentence in New Yorker’s (February 23) article, titled “In Defense of Liz Lemon”:     “She behaves as if Jack Donaghy (Alec Baldwin) is her daddy. She   doesn’t trust her own judgment, she’s bad at her job, and there’s   something awfully misogynist about all this! Liz Lemon is pathetic.”   When I checked the word, misogynist on dictionaries at hand, OALD defines it as “a man who hates women.” CALD likewise defines it as “a man who hates women or believes that men are much better than women.”  But here it is used for Liz Lemon, a woman. Is misogynist used only for male as both OALD and CALD define, or for both sexes?  According to www. memidex com, misogyny derived from modern Latin, misogamia from Greek “misein” (to hate) + “gamos” (marriage). Then, what is Latin equivalent antonym to misogamy?


Step 1: prove for  $n = 1$  1 < 2   Step 2:  $n+1 < 2 \cdot 2^n$  $n < 2 \cdot 2^n - 1$  $n < 2^n + 2^n - 1$  The function $2^n + 2^n - 1$ is surely higher than $2^n - 1$ so if  $n < 2^n$ is true (induction step), $n < 2^n + 2^n - 1$ has to be true as well.  Is this valid argumentation?

Prove that  $ n < 2^{n}  $ for all natural numbers $n$.  I tried this with induction: Inequality clearly holds when $n=1$. Supposing that when $n=k$, $k<2^{k}$. Considering $k+1 <2^{k}+1$, but where do I go from here?  Any other methods maybe?


I am getting started on the Blender Stack Exchange site and have asked a complicated question and am getting great answers. But I am told need 50 points to comment on answers. How do I deal with this?

Users with less than 50 reputation points cannot write comments on questions and answers that they don't own.  Why does this limit exist? But I want to contribute now. What should I do instead? But I can't write a good answer without more information! Shouldn't I be allowed to post comments if I have reputation on a different site? But I saw a new user posting a comment! How did they do it? Why do I need 50 reputation to comment on my own post?   See also:    in the Help Center


I'm using Xubuntu 16.04.1  For external reasons I cannot use apt-get.  I downloaded flash_player_ppapi_linux.x86_64.tar.gz and have extracted it but I don't know where to put each of the files, the readme does not have instructions.  In the archive are a few legal text files, the readme, libpepflashplayer.so and manifest.json.

Even though I have the latest Adobe Flash player 11.2 for Linux in Firefox -   - a particular online flash game still requests that I update to the latest flash player.  I've tried this online game on my laptop (Windows 8 with Flash Player 11.8) and it has no problems.  Is there a way to trick Ubuntu or this game into thinking Flash Player 11.8 is "installed"?


When I have a navbar as seperate div, how can I make the header full height of the screen? When I add 100vh it's too big, when users lands on website he can scroll. I need to add like 95.5vh instead to fit it perfectly, but I do not want to add custom height. How can I make it to be full height all time no matter the size of navbar? Is there something else than vh I could use?   header {   background: red;   height: 100vh; }  body {   margin: 0; }

Brand.

        Hello

I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ }

...

...

     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works.


I am trying to change chars pointed to by a char pointer variable:       char *test3 = "mutable";     printf("Expected: mutable, Result: %s\n", test3);     testt(test3);     printf("Expected tutable, Result: %s\n", test3);      void testt(char *s) {         *s = 't'; // FAILS, I get Segmentation Fault Error     }   Why does the above approach not work? Are chars pointed to by pointer variables immutable? If so, how would I modify the contents of the pointer variable?

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


This is my first post and as you can probably guess I am a mathematician so I have no clue about grammar. I am writing a mathematical document at the moment and I would appreciate some advice on my usage of capital letters. Can somebody please confirm if the following are correct?  1) "We know by Theorem 4.6.1 that..."   2) "the following conjecture, due to..."  3) In order to prove the "Mckay-Stevens $k$-covering Conjecture, once needs to show that..."  I'm particularly confused about 3).  Many thanks for any help

In many mathematics papers, I read sentences like:     With an appeal to Theorem 4.5 we get …   Is the capitalization of theorem in this case correct? If it is correct why do we capitalize the word?


I used to use cmd back in windows, and the command line I used a lot, was cls. It's kind of like the clear command used in Linux, but it cleans the screen permanently.  If you use the clear command, it just scroll down, so that you don't see the command you where working on.  I like both a lot, but my question is, how do i get a cls like command, that clears the screen, and can't browse up, to see the command you where working on?

I can issue the clear command or press Ctrl + L to clear the current Ubuntu terminal, but this just shifts previous output upwards and if you use mouse scroll or PgUP and PgDown keys it's hard to distinguish where the output of previous command ends and output of current command begins.  Is there a way to really clear the terminal so I won't see previous command results?