I do not see any bounty button. I've checked the FAQ and related questions, but I guess nobody has been so lame to ask this question so far. I'm a newbie to this site and my situation is like this:  my reputation is 51 the question age says 3 days  Are there any other requirements I have to meet to offer bounty for my question, that are not mentioned in FAQ? Or have I missed something?

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


I managed to show that if a random variable is constant : $P(X = \mu ) = 1$ then the Variance is zero:  $E[X^2] = \sum_{i = 1}^{k} p_iX_i^2 =>$ (given X_i is constant)$=> X^2\sum_{i=1}^kp_i = X^2 $  $E[X]^2 = (\sum_{i=1}^{k}p_iX_i)^2 = (X\sum_{i=1}^{k}p_i)^2 = X^2$  This is relatively straight forward with the for on the variance of $E[X^2]-E[X]^2$  However is the converse true? Does a zero variance necessarily imply a constant random variable?

We know that the variance of a constant is $0$. Is the converse also true? Can we say that if the variance of some random variable is $0$ it is a constant?


On my site, commenting is not enabled.  But at the top of each blog post (except for one, strangely), there's a 'Leave a reply' link.   (the link doesn't do anything -- but the words 'leave a reply' sitting there obviously make it look like you can leave a reply...)  I don't see any 'discussion module' in my edit-post page.  Here's an example page with a 'Leave a reply' link, just under the post title:    I'm on Mac Chrome -- in case it's a small browser-related bug...

On  I disabled  comments for "USDCAD options vs CADUSD options arbitrage?", but it  still has a "Leave a Comment" link.   Clicking the link takes you to    where it, of course, shows that you can't leave a comment.   The timeline page correctly does not show the 'comment' link:    How to fix?


I have gionee gpad g3 whose specifications are 512 mb ram, 1.2 ghz quadcore processor and 4 gb internal memory. my device is not listed on CM supportable device list. so should i install it?

My device is not listed as supported on website . I have ZTE Skate, and some other ZTEs are listed, but not mine.  Is it possible to install the mod on Skate, and what's the risk? If phone is not listed, does it mean, that it was just not tested, or the mod wouldn't work?


Can other users see exact number of things (edit, votes, review jobs), that I should do, to reach next badge? Or are they only able to estimate this, by looking at my badges ("guy has , but not yet , so he edited between 80 and 500 posts" -- or something like that)?

Is there a way to view your own progress towards certain badges? For example:   Tumbleweed - What value constitutes low views for a week? Fanatic  – Is there a way to view how many days in a row you currently have? Beta – Is it even possible to get this badge anymore?


On my Android Gingerbread device (keep in mind that it is the pratically extinct Walkman, which is basically Android's attempt at a iPod) my wifi keeps on going white, and when it happens I can't use Text+ and stuff like that. I have no idea why, but it keeps on doing that. When its green though, it lets me go on it. It toggles from normal connection to only games, basically. Anyone know why my wifi won't work?

The connectivity icons (Data, Mobile Signal, Wifi) in the status bar on my Nexus S are normally green, but sometimes they go white. I can't seem to figure out what this means, as I still have a signal and can receive phonecalls/texts.  They are always all the same, e.g. either all white or all green. I'm on Android 2.3.4.


Assuming NASA is aware of the capability of Martian winds to push heavy objects then why would they leave the MAV at Schiaparelli crater for years, knowing it could potentially be affected by the environment while there?  If it broke, or toppled, then the crew of Ares 4 could arrive and find that their journey was wasted because they can't risk landing if they have no means of escape.

At the beginning of the film The Martian, part of the dialogue implies that one of the crew has the job of monitoring the MAV to check it is still upright. The importance of this job is clearly shown when a storm hits.  Later we find out about another MAV which will be in place for a significant period of time before it is needed, yet no one shows any concern that it may also be at risk of toppling.  So given the importance of this escape craft, why wasn't any plan in place to tether the first craft? And were NASA just gambling on the weather that the latter MAV didn't topple before it was needed?


I am using scheme as shown below to blink an LED.     But I'm using 9V battery source instead of 12V.  I tried to use capacitors in range 100uF - 500uF to increase delay between blinks.  Questions:   When I tried put there 1000uF capacitor, there is no more blinking effect. LED is OFF. Why? When I put there 500uF capacitor, I thought the LED will blink with 0.5s interval as 10K * 500uF should be Tau = 0.5s. Actualy I see it blinking with interval 0.25s.

I am trying to learn basic oscillator circuits with the help of this   But when I connected the components, my LED is not blinking. Rather, it is giving bright light.  The components I have used are 1K resistor 18V battery 200uF capacittor 2N2222 transistor and LED with 100 ohm resistance.  Here is the circuit:      From above page:


Let $f:I \to \mathbb R$ be an increasing function where $I$ is an open real interval ; how to show that if for $c \in I$ there exist sequences $(a_n)$ and $(b_n)$ such that $a_n<c<b_n , \forall n\in \mathbb N$ and $\lim \Big(f(a_n)-f(b_n) \Big)=0 $ , then $f$ is continuous at $c$ ? ( I can prove the converse but having trouble with this one ; Please Help )

I want to show that if $f:(a,b)\to \mathbb R$ is a strictly monotone function and if $x_0\in (a,b)$ such that there exist two sequences $(a_n)$ and $(b_n)$ with $a_n<x_0<b_n$ and $\lim\limits_{n\to \infty}(f(b_n)-f(a_n))=0$, then $f$ is continuous at $x_0$.   By monotonicity we can say that $\lim\limits_{n\to \infty}f(a_n)=f(x_0)=\lim\limits_{n\to \infty}f(b_n)$. Let $(x_n)$ be a sequence in $(a,b)$ such that $x_n\to x$. Here I got stuck. How to show that $f(x_n)\to f(x_0)$? Please help!


I have read somewhere that electrons revolve around the nucleus and electrons are most probably found in orbitals. Can someone explain how electrons really revolve around nucleus through nodal plane in $p$ orbital?

My question isn't how they receive the energy to jump, but why.  When someone views an element's emission spectrum, we see a line spectrum which proves that they don't exist outside of their orbitals (else we would see a continuous spectrum).  Electrons can be released in the form of beta decay, thus proving that they are capable of traveling outside of orbitals contrary to the statement my teacher said that they stay within orbitals. Then, to add to the confusion, the older model of rings floating around a nucleus has, from what I can tell, been outdated, which would support this model. My teacher's explanation was that the electrons made a quantum jump of some kind. How do electrons move between orbitals or do we know how they jump, excluding the reason that energy causes them to jump, and why are positrons formed sometimes instead of electrons in Beta decay?  When I'm asking "how do electrons jump" I would like to know how an electron can jump between each orbital such as how it moves and how it knows where to jump since it appears to be a jump where the electron doesn't slow into a orbital position. Specifically how they jump what is this Atomic electron transition, I understand that they jump and that they do this through absorbing and releasing energy but what is this Atomic electron transition other than what is already on the wikipedia article .


Which is is the  best way to define a function in javascript . how to define a function  using ':' like  function_Name : function(){} .

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


I have 3 queries:  SELECT `update`.`id` AS `id`, `update`.`type` AS `type`, `update`.`date` AS `date`, `update`.`like` AS `like`, `update`.`dislike` AS `dislike` FROM `updates` AS `update` WHERE `type` = '1' ORDER BY `date` DESC LIMIT 1  SELECT `update`.`id` AS `id`, `update`.`type` AS `type`, `update`.`date` AS `date`, `update`.`like` AS `like`, `update`.`dislike` AS `dislike` FROM `updates` AS `update` WHERE `type` = '2' ORDER BY `date` DESC LIMIT 1 (1)  SELECT `update`.`id` AS `id`, `update`.`type` AS `type`, `update`.`date` AS `date`, `update`.`like` AS `like`, `update`.`dislike` AS `dislike` FROM `updates` AS `update` WHERE `type` = '3' ORDER BY `date` DESC LIMIT 1 (1)   I need to get last date for each type. How can I get it in one query?  Thank you.

Table:   UserId, Value, Date.   I want to get the UserId, Value for the max(Date) for each UserId. That is, the Value for each UserId that has the latest date. Is there a way to do this simply in SQL? (Preferably Oracle)  Update: Apologies for any ambiguity: I need to get ALL the UserIds. But for each UserId, only that row where that user has the latest date.


We know that surprisingly enough, $i^i=\frac1{e^{\frac\pi2}}$.  But what about finding the value of ${i^i}^{i\cdots}$? Is it possible?  My attempt: Let $${i^i}^{i\cdots}=x$$ $$i^x=x$$ Or $$\left(\cos\frac{\pi}{2}+i\sin\frac{\pi}{2}\right)^x=x$$ $$e^{\frac{\pi}{2}ix}=x$$ But can we take the $\log$ of both sides?  Even if we take, $$\frac{\pi}{2}ix=\log x$$ Now how to solve this equation?  Edit: OKay, as pointed by @JackD'Aurizio, that we have to first check whether the given sequence converges or not. But I have no idea for how to check that? (Please answer in elementary terms)

If $w = z^{z^{z^{...}}}$ converges, we can determine its value by solving $w = z^{w}$, which leads to $w = -W(-\log z))/\log z$.  To be specific here, let's use $u^v = \exp(v \log u)$ for complex $u$ and $v$.  Two questions:   How do we determine analytically if the tower converges?  (I have seen the interval of convergence for real towers.) Both the logarithm and Lambert W functions are multivalued.  How do we know which branch to use?   In particular $i^{i^{i^{...}}}$ numerically seems to converge to one value of $i2W(-i\pi/2)/\pi$.  How do we establish this convergence analytically?  (Yes, I have searched the 'net, including the tetration forum.  I haven't been able to locate the answer to this readily.)


An attempt to use generics with any class that extends Throwable produces an error saying "Generic class may not extend 'java.lang.Throwable'".    Sample code:  public class GenericException<T> extends Exception { }  // Compilation Error   I am not able to understand why generics cannot be used inside classes that extend Throwable.  Could someone explain?

According to the , 3rd edition:        I wish to understand why this decision has been made. What's wrong with generic exceptions?  (As far as I know, generics are simply compile-time syntactic sugar, and they will be translated to Object anyway in the .class files, so effectively declaring a generic class is as if everything in it was an Object. Please correct me if I'm wrong.)


I've got a greek keyboard and enjoy typing the greek letters directly into the mathmode using the unicode-math package. Yet, unfortunately it seems as though there is at least one symbol that does not survive the inclusion of said package, and this symbol is \setminus; it just disappears whenever said package is being included.  I'm using XeLaTeX in order to compile my document.  EDIT: As requested by the commenter:  \documentclass[10pt,a4paper]{article}  \usepackage{amssymb}  \usepackage{fontspec} \usepackage{xunicode} \usepackage{polyglossia} \usepackage{xecyr} \usepackage{unicode-math}  \setdefaultlanguage{english}  \setmainfont{GentiumPlus}  \usepackage{amsmath} \usepackage{amsfonts} \title{Error demonstration}    \begin{document} \begin{equation*} A \setminus B \end{equation*} \end{document}

What can i put into \setmathfont{<...>.otf} for the unicode-math package to make it all work (with XeLaTeX or LuaLaTeX)?  There are several suggestions on the  of unicode-math, but the first option is commercial, and the second and the third do not work with the following example:  % !TEX TS-program = xelatex  \documentclass{article} \usepackage{unicode-math} \setmathfont{latinmodern-math.otf} % \setmathfont{texgyrepagella-math.otf} % \setmathfont{xits-math.otf}  \begin{document} $X\setminus Y$ \end{document}   I do not get the \setminus character in the output.  The \setminus character is also missing if i do not set a math font at all (i do not know which font is used in this case).  It works with xits-math, but i do not like it.  Is it expected by the way that the \setminus character is left blank without giving any warning?


I keep getting a java.lang.NullPointerException when trying to open a txt file in eclipse. Basically, this is a main menu, and when you click the "Rules" button, the rules text file should open. Currently, the txt file is located in a package called "Resources" (which is where all of the other img files I've used in making the game are). Here's the code:  private List<String> readFile(String filename) {   List<String> records = new ArrayList<String>();   try   {     BufferedReader buff = new BufferedReader(new InputStreamReader(             Configuration.class.getResourceAsStream(filename)));     String line;     while ((line = buff.readLine()) != null)     {       records.add(line);     }     buff.close();     return records;   }   catch (Exception e)   {     System.err.format("Exception occurred trying to read '%s'.", filename);     e.printStackTrace();     return null;   } }  //action performed public void actionPerformed(ActionEvent ae) {     JButton b = (JButton)ae.getSource();     if( b.equals(newGameButton) )         {         flag = true;         controller.startGame();         buttonPressed = "newGameBtn";         }     if(b.equals(quitButton))     {         System.exit(0);     }     if(b.equals(ruleButton)){         readFile("../resource/riskRules.txt");     }   }  Appreciate the help!

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


I want to overlap both LiDAR data and SRTM data but they use different vertical coordinate systems.  I am using ArcMap 10.2 and I firstly created a LAS dataset and original vertical coordinate system of LAS dataset was Unknown VCS from ArcInfo Workstation (I didn't choose any vertical coordinate system. And this one appeared). And then, I created a new LAS dataset and chose vertical coordinate system as EGM96 which SRTM data and Google Earth have. But elevation values of LiDAR points did not change. Still have different values from Google Earth and SRTM data. I need LiDAR to have same elevation values with SRTM for the same region.  Is there a way to make LiDAR and SRTM data the same vertical values for the same point on the map?

How can one change a coordinate system for a .lasd (Lidar) dataset?  The file is currently in UTM_Zone_15N and I am trying to convert it to IL_East.


When I try to ulimit -n 4097 or greater I get the following error:  bash: ulimit: open files: cannot modify limit: Operation not permitted   None of the solutions at  seem to work or apply.  I can raise the limit to 4096 but not beyond.  Output of ulimit -n -H 4096  Edit:  Problem solved:

This is happening on Ubuntu Release 12.04 (precise) 64-bit Kernel Linux 3.2.0-25-virtual  I'm trying to increase the number of open files allowed for a user. This is for my eclipse java application where the current limit of 1024 is not enough.  According to the posts I've found so far, I should be able to put lines into   /etc/security/limits.conf like this:  soft nofile 4096 hard nofile 4096   to increase the number of open files allowed for all users.  But that's not working for me and I think the problem is not related to that file.  For all users, the default limit is 1024, regardless of what is in /etc/security/limits.conf (I rebooted after changing that file)  $ ulimit -n 1024   Now, despite the entries in /etc/security/limits.conf I can't increase that:  $ ulimit -n 2048   -bash: ulimit: open files: cannot modify limit: Operation not permitted The weird part is that I can change the limit downwards, but can't change it upwards - even to go back to a number which is below the original limit:  $ ulimit -n 800 $ ulimit -n 800  $ ulimit -n 900  -bash: ulimit: open files: cannot modify limit: Operation not permitted   As root, I can change that limit to whatever I want, up or down. It doesn't even seem to care about the supposedly system-wide limit in /proc/sys/fs/file-max  # cat /proc/sys/fs/file-max 188897  # ulimit -n 188898 # ulimit -n  188898   But even I get eclipse to run as root, my application still crashes because of "Too Many Open File" exception!   So far, I haven't found any way to increase the open files limit for a non-root user.  How should I properly do this? I have looked at several other posts but no luck!


I'm very (very) new to photography world.. I've been trying in the past few days to explore very deeply to this world.. But the more I dived in the more confused I became.    For example most of the videos that I've seen in YouTube and a lot of articles said that the focal length is the measurement between the front lens and to the convergence point, but some said (and it sounds more sense to me) that it actually from the convergence point to the sensor, so what is the truth?

I read on the :     Focal-length determines the angle-of-view seen through a lens for a   given sensor-size. With a full-frame sensor a lens gives the same   angle-of-view as it would on a 35mm film camera. With a smaller   sensor, the angle-of-view becomes smaller. The crop-factor, also   called FLM, is the ratio representing the difference in equivalent   focal-lengths. So a 150mm on a full-frame DSLR such as the Nikon D700   gives the same angle-of-view as a 100mm on a D7000 since its FLM is   1.5X.      Short focal-lengths show a greater angle-of-view compared to longer   ones. [...]   In layman's terms, what is angle-of-view? Is it the same as focal length? If not, how is it different? How is it used? Why do I need to know about it?


The code:  public class UnitOfWork : IUnitOfWork  { ...     ~UnitOfWork()     {         dispose(false);     } }   What the ~ means?  Full code is here:

I am looking at some code and it has this statement:    ~ConnectionManager() {     Dispose(false); }   The class implements the IDisposable interface, but I do not know if that is part of that the tilde(~) is used for.


In java, I use the   variable = something == 1 ? 1 : 0   function all the time. Is there an equivalent function in python?

If Python does not have a ternary conditional operator, is it possible to simulate one using other language constructs?


I shouldn't get it :-) I linked that question from the main CodeGolf site. I am 100% certain that I linked this question only within SE. Why would I link this very particular question from the outside webs?  Is this a bug or a feature?  I think it shouldn't be like that - you should be awarded for your effort outside to let people know about SE. Linking within SE is valuable, but I feel these badges are intended for propagating SE and it should be consistent in that.  EDIT: thanks to the discuters.

I suspect that some bug makes internal linking count towards Publicity badges too. The badges :  These badges are specifically for linking to questions like the description says. The link must be clicked from outside the network in order for it to count for this purpose.  However, 2 days ago I was  for a question that I really feel does not need such linking to start with: . Also, I always try to use full links. And above all:  for the link gives me a single hit, for . Maybe it's thinking that empty REFERER headers (for those that block that, or for Safari users who ) should be counted too? Or maybe some search bot is using lots of IP addresses? Or visitors of Stack Overflow clones are to blame?


What numbers can be written as the sum of two triangular numbers? i.e.,  $$\frac{x(x+1)}{2}+\frac{y(y+1)}{2}=z $$  $4z+1$ is either the sum of two squares or itself a square. Why?

Is it possible to figure out if a number $z$ is the addition of two triangular number without recursion or finding the values to $x$ and $y$?  $$\frac{x(x+1)}{2} + \frac{y(y+1)}{2} = z$$  An example of this would be following:   $$\frac{345(345+1)}{2} + \frac{234(234+1)}{2} = 87180$$  Is it possible to determine if $87180$ originated from the addition of two triangular numbers without recursively going back and plugging every possibility for $x$ and $y$?


I'm am new to this ubuntu but wanna use it. I got a HP laptop with 1tb hard disk in it with windows 7 as default os i had erased my windows and installed ubuntu 13.04 fresh. So can any one help me how to create ntfs partition so i can store my files, movies etc in it please.

I have installed ubuntu 12.04 and I need to make a new partition out of my system partition. That partition should be readable  by windows 7 in order to ease dual boot with Ubuntu. How can I proceed ?


Learning topology has been hard. I just cannot see how some people can come up with complex functions that link one space to another, in a homeomorphic sense.  The explanations are always "Well if you define this kind of function it satisfies continuity, bijectivity so there" Which is irrefutable simply because that person is (mathematically) right.  I've always been wanting the "how did that function pop in your head."  What motivated you to think of such a function in the first place? A wild and lucky guess? Well that's not mathematical or logical, it can't be.  My conclusion is that these people "know" some of the well-known, most seen, most common homeomorphisms by heart and tweaks it here and there to build a new one to adapt. So I guess that's why they cannot answer to my "but how did you find that function?" I also often see "$X$ and $Y$ are clearly homeomorphic so..." in a discussion, where, to those practiced minds it is indeed crystal clear but to me, I cannot say "hmm, yes because well...uh huh, here's an example of a homeomorphism between $X,Y$ so yes, go on..."  I'm like, "but what's the homeomoprhism? I don't know where to start from scratch! What is the train of thought??"  Words like obvious bijection, or natural way of mapping only makes sense once one has seen these specifically and gotten comfortable with it. It's hard to explain why it's obvious because it is obvious but that's an issue when the less experienced is not comfortable with the notion of just obvious.  This is the problem with a lot of my professors too. They've been doing it for decades. Most may be born with topolo-genes (as I call it) who gets most of the abstract concepts in the speed of light. Perhaps that's why they don't understand why students like me say "it's obvious to you and you indeed sound convincing and I cannot argue back, but I simply can't feel comfortable"  In a nuthsell, at this level, things just seem to come out of nowhere(but still, correct and rigorous).   So my response now is to at least familiarize myself with these common homeomorphisms. Just remember them for now, use them like an idiot and gradually gain comfort.     So my request here is this: Would people provide me as much examples as possible(proof not necessary but appreciated of course) of most basic, common homeomorphisms between spaces?  For instance, the homeomorphism between a disk in a plane and a square? or something in $\mathbb{R}^n$?   It would be great if I can get "a homeomorphism between $X$ and $Y$ is given by $f$" for the spaces you think are standard and know by heart. Even without thinking maybe.   I am thinking this should help me build on intuition and topolo-sense (take it as a topology version of spider-sense) which I lack severely.

So, I don't like proofs.  To me building a proof feels like constructing a steel trap out of arguments to make true what you're trying to assert.  Oftentimes the proof in the book is something that I get if I study, but hard to come up with on my own.  In other words I can't make steel traps, but I feel fine buying them from others.  How does one acquire the ability to create steel traps with fluency and ease?  Are there any particular reference books that you found helped you really get how to construct a proof fluently?  Or is it just practice?


console.log(0.03 %  0.01);  When i run this calculation i get the following result:  0.009999999999999998  In my understanding the result should be 0, what is going on here?

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


I have bumped into one simple task which I am not able to prove:  How to prove, that number $ \frac{1000!}{(100!)^{10}} $ is integer?

How to show $(mn)!$ divides $(m!)^n$, $m$ and $n$ is integers?


I was curious if the curving of spacetime by mass/energy was actually a real thing or is it just a mathematical construct, a way of visualizing the force of gravity and explaining it and that there is not truly a "fabric of spacetime" and this fabric doesn't actually curve. The math simply explains our observations, but isn't literally what is happening.  I'm looking for a pure GR/SR answer to this, not asking about newer theories that build on GR. Did Einstein himself believe spacetime and its curvature was a real physical thing or did he know he was just using math and geometry to explain a phenomenon everyone can see/feel?

I get the curvature tensor in General Relativity, it is “just” math. Does space-time REALLY curves as a tangible thing, or is Einstein proposing a mathematical abstraction?  More naively, please allow, is space-time a real physical “something” like a “new ether”? If yes, does anyone have any idea what is it made off?


Our young grandson, who is a Mancunian, says 'give it me', and 'give it me back', which is a northern British standard.  It made me think that it is not only northerners who omit the indirect object preposition 'to'. Americans will say 'write me, and let me have some news'.   In the latter case the pronoun 'me' appears as though it has actually become a direct object of an alternative verb 'to write' which is transitive, but with a slightly different meaning to that used in 'write the answer in the left hand column'.  Does anyone else look at it in that way?

When I call the buzzer outside my girlfriend's flat, she sometimes says *"I'll open you the door". I correct this to "I'll open the door for you".  I've never heard a native speaker say it the first way, which is why I think it's wrong. But I can't explain why.  There is a pattern in lots of English phrases that would suggest both are correct. A few common examples:   Give the keys to me before you go — Give me the keys before you go I'll buy a coffee for you at the cafe — I'll buy you a coffee at the cafe We sent a text to Martin on his birthday — We sent Martin a text on his birthday   The left-hand side is more formal, and the right-hand side is more common in everyday speech.  What do you call this pattern?  What makes the 'open-the-door' sentence an exception?


I have win 8.1 preinstalled.I installed  ubuntu  in a drive.but during the booting it is not asking which os is to boot and autometically win is booting.please help me.I am using hp laptop with preinstalled win 8.1

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I am following CG Geek's  and I want to export this tree, shaders and all, to Unity so I can add it to my game. How would someone go about exporting a (Cycles Rendered) mesh To Unity? Thank You In advance! (BTW, I know there are a lot of people that already asked this but I tried them and they don't work. Also (I think), my circumstance is kind of specific)

I used node textures in a mesh I exported to .FBX.  I then imported it into Unreal Engine 4 and it didn't import any textures; I clicked the Upload Textures option in Unreal Engine.  Is there something I'm doing wrong or is it Blender?


This will be my first question at the stack exchange, so please bare with me.  I'm doing a course on Matrix Groups for my Honours year and have really been struggling.  How would I go about solving this?  Let $G$ be a finite group and $g \in G $ is such that $\{g,g^2,g^3,\ldots\}$  is finite. Show that there exists a positive integer $k$ such that $g^k=1_G$  Any help would be greatly appreciated. Thanks!

I work in population dynamics. I want to show somewhere in my work that the $h-$th power of every element in a finite group of order $h$ is the identity element of the group. I guess this is elementary result but it would be nice if somebody show me how to do it or where to find it. Thanks


var hungry = true; var foodHere = true;  var eat = function() {   if (hungry && foodHere === true) {       return(true);   } else {       return(false);   }`  };   The first line is the correct syntax. For a long time I was just saying hungry && foodHere = true... and I couldn't figure out (and still don't understand) why that is wrong. I understand the difference between = (assignment) and === (equal to). I assigned the variables to be true initially, so aren't I asking in the if statement if that's what they're set to? Why am I setting the variables = to in the var definition, but then when checking them I'm using the === value?

I'm using  to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value.length == 0 inside of an if statement.  Is there a performance benefit to replacing == with ===?   Any performance improvement would be welcomed as many comparison operators exist.  If no type conversion takes place, would there be a performance gain over ==?


how can I found/use/make a shader in Blender which allows me to use the textures from Substance Painter? I would prefer to be free.  Thanks

I have decided to work with Substance B2M en use the texture maps in Blender. I want to work with the PBR shaders of Cynicat Pro and connect the Substance maps into the input nodes of the PBR Shaders. I especially want to know which texture maps of Substance (base, normal, height, specular, metallic, ...) are relevant for Blender and if they have the same meaning (like the specular and metallic map) and how to connect these maps to the input nodes.  I am mostly interested in the definitions of the texture maps in both packages and whether or not they match.  After reading the blog of Jason alias @Jtheninja, I set up a node group using the Metallic Shader of Cynical Pro and connect the Substance texture maps.     Would this make sense for a rusted metal?


I have this code and my if statement always returns false even though I entered the right inputs.      boolean z = false;     String x, y;      Scanner cin = new Scanner(System.in);      System.out.println("enter x");     x = cin.nextLine();      System.out.println("enter y");     y = cin.nextLine();      if(x == "x" || y == "y") {         z = true;     }      System.out.println(z);     if (z) {         System.out.println("successful");     }

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?


Is there a real number $M >0$ such that $$S_n \leq M, \forall n \geq 1$$  where    $$  S_n = \sum_{k=0}^{n-1}\binom{n}{k}^{-1}, n\geq 1.$$   Thank you in advance

How to calculate the sum of sequence $$\frac{1}{\binom{n}{1}}+\frac{1}{\binom{n}{2}}+\frac{1}{\binom{n}{3}}+\cdots+\frac{1}{\binom{n}{n}}=？$$ How about its limit?


Compute the following limit: $\lim\limits_{n\to \infty}2n \int \limits_0^1\dfrac{x^{n-1}}{1+x}\,dx.$   The value is 1. I have done this by squeezing it. Is there any other way to evaluate this ?

Let $s_n$ be a sequence defined as given below for $n \geq 1$. Then find out $\lim\limits_{n \to \infty} s_n$.   \begin{align}   s_n = \int\limits_0^1 \frac{nx^{n-1}}{1+x} dx  \end{align}  I have written a solution of my own, but I would like to know it is completely correct, and also I would like if people post more alternative solutions.


There are certain quest series (like Nabbed from Nuka-World) that have the "Limited Time" Tag. When do they expire?

With the last update of Fallout Shelter, Bethesda has added these "limited time" quests.  Question is, how limited is that time exactly? What happens when the quests "end", will it still be possible to get the benefits?


I tried  and   with the same result:  root@avilellaM710t:/home/avilella# sudo adduser avilella sudo          The user `avilella' is already a member of `sudo'. root@avilellaM710t:/home/avilella# exit a vilella@avilellaM710t:~$ sudo ls [sudo] password for avilella:  avilella is not in the sudoers file. This incident will be reported.  avilella@avilellaM710t:~$ whoami avilella   Also, see:  root@avilellaM710t:/home/avilella# cat /etc/sudoers # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults        env_reset Defaults        mail_badpass Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  # See sudoers(5) for more information on "#include" directives:  #includedir /etc/sudoers.d   Any ideas?

After I add a user using adduser, I can't see it via System > Administration > Users and Groups unless I log out and then log in again. Is that normal?  Also, can I set a newly added user as a sudoer or do I have to change that only after adding it? How can I do that via the shell?  Finally, can I delete the original user that was created upon initial installation of Ubuntu, or is this user somehow 'special'?


Use induction to establish the divisibility statement $8 | 5^{2n}+7$. I am going to assume that establish means prove here. Here a hint is given: $5^{2(k+1)} + 7 = 5^{2}(5^{2k} + 7) + (7 - 5^{2} * 7)$. As far as I can see from a glance it's obvious that the value of $0$ for n works but I still don't know  how to prove that using induction here.

So I'm trying to use mathematical induction to show that for all integers $n \ge 1$ ,  $$ 8|(3^{2n} - 1)$$  (is divisible by 8)  I have my base case: [P(1)],  $3^2 - 1 = 9 - 1 = 8$, since $8|8$, the base case proves true  Assume [P(k)], $ 8 | (3^{2k} - 1)$.  I know that I need to show [P(k+1)], $ 8| (3^{2(k+1)}-1) $, but I'm not sure how to prove this. I've only been using induction for summation, so how could I prove divisibility?


I have two modules but they are copy paste of each other and I just change their labels in property files but their attributes are same. I have hosted like this: For example:       How can I run two different sessions on same domain? UPDATE The main problem I found is that when one session is created then login to other module is not setting session.setAttribute() and if(session==null) printing false and message already logged in appears because previous session is not yet ended.  May I add them in webapp as two different project instead of one project? Or can I use one session class for both module?

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?


A chart with data in the range of 200,000 and small difference between max and min values, will be assigned a 10^5 multiplier to the entire axis. This results in the ticks becoming meaningless, since all become 2.   Example:-  \begin{tikzpicture} \begin{axis}   \addplot coordinates {   (100,200001)   (200,200003)   (300,200005)   };     \end{axis} \end{tikzpicture}   When this is plotted the y-axis has 5 ticks, all of which are 2. The y-axis has a multiplier of 10^5. This has effectively removed all information from the graph.  I may use the below to set the explicit value of the tick values but this does not implement change in the display "style" of the axis ticks.  ytick = {200000, 200005, 200010}   I have also tried increasing the precision of the tick label to 5. However this only results in the graph showing labels such as 2.00000, 2.00005, 2.00010 with a 10^5 axis multiplier.  yticklabel style={precision = 5,}   My question is "How do I remove/change this 10^5 multiplier, such that the y-axis ticks are displayed in the form 200000, 200005, 200010.


Is it possible to set and expiration date for the file http://assets.pinterest.com/js/pinit_main.js? And the other stuff down the list?   I want to bring up my score as high as possible. I'm using WordPress by the way.

I tested my website with Google PageSpeed Insights.  I did cache optimization in my .htaccess, but it didn't affect resource files that are from Facebook and Google+  Leverage browser caching      http://connect.facebook.net/fr_FR/all.js (20 minutes)      https://apis.google.com/js/plusone.js (30 minutes)      https://oauth.googleusercontent.com/…e:rpc:shindig.random:shindig.sha1.js?c=2 (60 minutes)   What can I do to solve this?


I want to upgrade to the newest version of ubuntu but I don't want plasma5 KDE desktop. is there a way to do the upgrade without sorting through a few thousand packages and dependencies?  my question is different because I want to prevent the upgrade of the entire desktop environment, but allow the base system to upgrade.this involves several hundred files and dependencies that keep trying to remove the entire desktop. (the change from plasma 4 to plasma 5 a completely new desktop evnroment, like going from kde to gnome).  look at my answer this is not a duplicate question. this process involved 600 packages. sorting by hand took 3 hours.and would be impossible to do by command line holds

Because of  I'd like to prevent apt-get upgrade and Update Manager from updating the "libgtk2.0-0" package.   How can this be achieved?


I need grep's output to be indented with tabs/spaces.    This is the plain, un-indented version:  MyCmd | grep "id:"  I tried this without success:MyCmd | grep "id:" | echo "   "

I am looking for a command line or bash script that would add space 5 times before the beginning of each line in a file.  for example:  abc   after adding spaces 5 times        abc


The  mentions on page 6 that "Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact.", and shows that their micro load models even still require a minimum of 1mA @ 5V. Their  goes further and explicitly marks the low end as being an "inoperable range". But neither datasheet explains why a microswitch would have a problem with a low load condition. Why is this, and what would happen if a microswitch was operated at loads lower than the minimum operating range?

I am trying to find relays for my application and I read  which looks fine but specifies     Minimum applicable load: 10mV 10µA   In my circuit, it is expected that the relay closes but no voltage and current is applied. You can think of it as 2 relays in series where one is open and one is closed, so there is no current. This sounds like something I'd do since I was at school.  Why would a relay require a minimum voltage and current on the load side? Is it allowed to operate that relay under my conditions or not? What could possibly break in a relay if I don't respect this requirement? What does "minimum applicable load" mean? When and how do I need to consider this value?


The  spell's description states:     it gains an additional action on each of its turns. That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action.   When looking at this Q/A ("") I realized grapple/shove state:     You can use the Attack action to make a special melee attack...   Both of them are considered melee attacks but are not weapon attacks. Does this really mean you cannot grapple or shove when taking haste's Attack action?   Note: I am asking this even though it seems clear to me that you cannot grapple/shove through haste because perhaps (hopefully) there is some specific exception I've missed somewhere.

(PHB p. 195) states:     Using the Attack action, you can make a special melee attack to shove a creature   Can the additional attack action granted by the haste spell also be used to shove a creature?


I'm trying to write "3 and a half year old," as in, "He is a 3 and a half year old dog".    I know a hyphen or two is supposed to go in there somewhere.  Per  , I suspect it should be "3-and-a-half-year-old", but that reads like death-by-hyphen, even if it is correct.  What's the proper way to hyphenate "# and a half year old" in this context?

Would "mid-to-late" and "low-to-mid" be hyphenated as compound modifiers?  Examples:  Temperatures are expected to be in the low-to-mid 60s.  Joe, I think, is in his mid-to-late 80s.  He was in his middle-to-late 40s.  She was in her middle-to-upper 60s.  Temperatures are expected to be in the lower-to-middle 70s.  Are all correct?  Thanks!!!


I would like to backup every important file on my computer such that in the event I lose all my data I can get my computer back to its "normal" state as fast as possible. I have a large hard drive (~500GB) to store my backup on, so memory is not an issue. Obviously I should backup my home directory, but what else? For example, should I back up my /usr/ directory as well?

If I want to make a backup of everything I have done since the fresh install of Ubuntu, what are the possible options? What all should I backup? I want to get all the settings that I changed, all the packages I installed, etc.


I used WinToFlash to clone a Windows CD to a USB to make it bootable.  Is there a way I can push Windows Updates to the USB so WU does not take as long to run?

What options, if any, exist for offline update of Microsoft  Windows?  If a solution exists please list your experience using it.    Background:  If for any reason a computer does not have a connection to  the Internet or the connection is too slow to download  several hundreds of megabytes every so often some kind of  offline Windows Update is required.  In a multi-computer environment a lot of bandwidth (and thus in some cases money) and/or  time could also be saved if it is possible to update in an  offline manner.


Ok, so I have a document where I made use of \autoref.  I've been told now, that we want all chapters, sections, subsections, etc. capitalised.  Since there is no \Autoref and I couldn't get its implementation from     to work, I tried going with another answer therein and replaced all \autoref{foo} instructions with \Cref{foo} from the cleveref package.  But now all references show up as ??.  I'm use the memoir document class and texmaker, I run  \usepackage[nameinlink,capitalise,noabbrev]{cleveref}   and I compile the document with Texmaker's  PdfLaTeX + Bib(la)tex + PdfLaTeX (x2) + show PDF   command.  How do I make \Cref work?

The hyperref documentation says: "Make sure it comes last of your loaded packages". The reason is that it redefines many LaTeX commands. It's a rule of thumb that helps to avoid errors.  However, there are exceptions, for instance the amsrefs user's guide notes that amsrefs has to be loaded after hyperref.  To avoid problems when adding hypertext functionality: do you know further such exceptions?


I have a fresh install of Ubuntu 16.04 on a brand new Dell XPS 13 9365 but the wireless isn't working ( however ethernet is ). I've looked at numerous forum posts for possible fixes and have tried a number of things with no success, including:   purging/installing bcmwl-kernel-source sudo service network-manager restart disabling Secure Boot using proprietary drivers and sudo apt-get upgrade   but nothing has worked. here's potentially relevant info:  sudo lshw -C network    *-network UNCLAIMED             description: Network controller        product: Intel Corporation        vendor: Intel Corporation        physical id: 0        bus info: pci@0000:3c:00.0        version: 78        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress cap_list        configuration: latency=0        resources: memory:c8a00000-c8a01fff   *-network        description: Ethernet interface        physical id: 2        logical name: enxd481d70b47bb        serial: d4:81:d7:0b:47:bb        size: 1Gbit/s        capacity: 1Gbit/s        capabilities: ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8152 driverversion=v1.08.2 duplex=full ip=10.1.10.41 link=yes multicast=yes port=MII speed=1Gbit/s   ifconfig  enxd481d70b47bb Link encap:Ethernet  HWaddr d4:81:d7:0b:47:bb             inet addr:10.1.10.41  Bcast:10.1.10.255  Mask:255.255.255.0           inet6 addr: 2603:300a:50f:4500::82c0/128 Scope:Global           inet6 addr: fe80::c25f:25b2:a543:41ab/64 Scope:Link           inet6 addr: 2603:300a:50f:4500:3820:773e:d850:bf44/64 Scope:Global           inet6 addr: 2603:300a:50f:4500:247e:8cc3:8c88:768c/64 Scope:Global           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:3297 errors:0 dropped:0 overruns:0 frame:0           TX packets:3088 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:1520006 (1.5 MB)  TX bytes:435638 (435.6 KB)  lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:1291 errors:0 dropped:0 overruns:0 frame:0           TX packets:1291 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1            RX bytes:116776 (116.7 KB)  TX bytes:116776 (116.7 KB)   iwconfig  lo        no wireless extensions.  enxd481d70b47bb  no wireless extensions.   cat /etc/network/interfaces  # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback   lspci -knn | grep Net -A2  3c:00.0 Network controller [0280]: Intel Corporation Device [8086:24fd] (rev 78)     Subsystem: Intel Corporation Device [8086:8050]     Kernel modules: wl   cat /etc/NetworkManager/NetworkManager.conf  plugins=ifupdown,keyfile,ofono dns=dnsmasq  [ifupdown] managed=false

I searched many solutions on this site but most of them were referring to Broadcom Wifi drivers while mine has Intel one.   Output of lspci -knn | grep Net -A2  arijit@HP-AU134TX:~$ lspci -knn | grep Net -A2  05:00.0 Network controller [0280]: Intel Corporation Device [8086:24fb] (rev 10) DeviceName: Intel Dual BandWireless-AC 3168 802.11 ac 1x1 WiFi + BT 4.0 Combo Adapter Subsystem: Intel Corporation Device [8086:2110]   Output of rfkill list  arijit@HP-AU134TX:~$ rfkill list  arijit@HP-AU134TX:~$    i.e No Output  Output of uname -a; dmesg | grep iwl  arijit@HP-AU134TX:~$ uname -a; dmesg | grep iwl  Linux HP-AU134TX 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux


This is part of an exercise I'm doing, from Rotman Introduction to homological algebra.  Let $R$ be a commutative ring, and let $A$ and $B$ be finitely generated $R$-modules.   Then if $R$ is noetherian, prove that $\hom_R(A, B)$ is a finitely generated $R$-module.  I'm stuck on it, any hint ?

This is an exercise from Rotman, An Introduction to Homological Algebra, which I've been thinking now and then for a few days and I haven't solved it yet. I've decided to ask here because it is bugging me and I don't have any friends also studying this subject (in case it is of any use, I'm an undergraduate).     Let $R$ be a commutative noetherian ring. If $A$, $B$ are finitely generated $R$-modules, then $\operatorname{Hom}_R(A,B)$ is a finitely generated $R$-module.   Here's what I've thought as of yet (maybe the problem is that I haven't been trying to apply the useful theorems...):  First of all, since $R$ is noetherian, it suffices to inject $\operatorname{Hom}_R(A,B)$ into some finitely generated module (in noetherian rings, submodules of f.g. are f.g.).  Now, since $R$ is commutative (or since $R$ is noetherian), a finitely generated $R$-module is a quotient of $R^n$ for some $n$. Then let us write $A\simeq \frac{R^n}{I}$ and $B\simeq \frac{R^m}{J}$. Now we've got:  $\operatorname{Hom}_R(A,B)\simeq \operatorname{Hom}_R\left(\frac{R^n}{I},\frac{R^m}{J}\right)$.  If I had $\operatorname{Hom}_R\left(\frac{R^n}{I},\frac{R^m}{J}\right) \hookrightarrow \operatorname{Hom}_R(R^n, R^m)$ (this is what I tend to think is the wrong direction, but a interesting question-rising path nevertheless) then it would be over since $\operatorname{Hom}_R(R^n, R^m)\simeq R^{nm}$ which is finitely generated.  So I ask myself: can I see $\frac{R^n}{I}$ as a submodule of $R^n$? Because if I could, then doing the same thing for $R^m$ and passing it to the hom, then it would be over. Now, this would be true if the sequence $$0\to I\hookrightarrow R^n\to \frac{R^n}{I} \to 0$$ split. But this (of course) doesn't always happen. But if I somehow had the third module to be projective, or the first one to be injective, then it would happen.  But why would, for example, be $\frac{R^n}{I}$ be projective?  And this is where I got stuck. I'm sorry if this is overly detailed, but I remember reading that it is always good, when asking about a textbook question, to add what you've thought up to that moment. Also, even if my thoughts don't lead to the solution, I would like to know if they are correct!


How is energy acquired from ATP (i.e. What is the energy-releasing equation involving ATP plus water)?  I Would be grateful for the answer.

When ATP is used as the energy currency to make, say, reaction X + Y → Z happen, is what happens on a physical level down at the molecular scale that during the reaction    ATP + H2O → ADP + Pi       ΔG˚ = −30.5 kJ/mol (−7.3 kcal/mol)    that 30.5 kJ/ mol is conferred by ATP molecules physically bumping around the reactants X and Y, the kinetic energy of the above reaction being what does it?  I mean, is the energy coin of ATP conferred to reactions by molecular collisions, or is it an electric field effect in the spatial geometry the way the ATP molecule tends to break apart?


How do I get the next date(2014/03/21) given the current date(2014/03/20) in Java?  Code:   public static String getNextDate(String  curDate) {          String nextDate="";         try {            //here logic to get nextDate         } catch (Exception e) {             return nextDate;         }         return nextDate;     }

I'm working with a date in this format: yyyy-mm-dd.  How can I increment this date by one day?


In Yosemite when I press a window's green 'fullsize' button, it will be full size, but somehow differently from earlier way, I can not use change between windows shortcut, because window will claim the whole screen. Any idea how to use it earlier?

On Mac OS X Yosemite the green icon in every window:    is by default used to make the application full screen.  How do I make it work the same way as in previous versions of Mac OS X, i.e. to maximize the window?


The derivative of a real-valued function at a point is the slope of the function at that point.  Similarly, what is the physical or geometric meaning of the derivative of a complex-valued function at a point?

What's the geometrical meaning of $f'(z)$ in complex analysis, as we know in real analysis $f'(x)$ has meaning ie. Slope of curve or gives max/ min. But what does derivative $f'(z)$ has geometrical meaning in complex analysis


Hey guys I've been trying for the last 3 hours to work out how to get WinUSB to get this onto my USB but it keeps giving me failed when I try I thought it was permissions so I tried   chmod 777   but it still wouldn't have it here are the errors any help is appreciated  Installation failed ! Exit code: 512 Log: Formating device... Mounting... mount: block device /james/Windows_8.1_Pro_X64_Activated_Final/Windows_8.1_Pro_X64_Activated.iso is write-protected, mounting read-only Copying... Error occured ! Syncing... Cleaning... /usr/bin/winusb: line 78: 14111 Terminated              while true; do     sleep 0.05; echo 'pulse'; done Umounting and removing '/media/winusb_iso_1389165798_11743'... umount: /media/winusb_iso_1389165798_11743: device is busy.         (In some cases useful info about processes that use          the device is found by lsof(8) or fuser(1)) Umounting and removing '/media/winusb_target_1389165798_11743'...

I'd like to create a Windows bootable USB stick, but I don't have a Windows machine with me at the moment to do so. How could I achieve the same using Ubuntu?


Prove: Let $(a_n)_{n=1}^\infty$ be a monotonously falling sequence of non-negative real numbers, so that $\sum a_n$ is convergent. Then $(na_n)$ is a sequence converging to 0.  Well, no idea. All help is greatly appreciated!

I'm studying for qualifying exams and ran into this problem.  Show that if $\{a_n\}$ is a nonincreasing sequence of positive real numbers such that $\sum_n a_n$ converges, then $\lim_{n \rightarrow \infty} n a_n = 0$.  Using the definition of the limit, this is equivalent to showing \begin{equation} \forall \varepsilon > 0 \; \exists n_0 \text{ such that } |n a_n| < \varepsilon \; \forall n > n_0 \end{equation} or \begin{equation} \forall \varepsilon > 0 \; \exists n_0 \text{ such that } a_n < \frac{\varepsilon}{n} \; \forall n > n_0 \end{equation} Basically, the terms must be bounded by the harmonic series. Thanks, I'm really stuck on this seemingly simple problem!


i'm stay crazy i just want use the loop while to read some ages on Java terminal  public static void main(String[] args){      Scanner keyboard = new Scanner(System.in);      int lenghtMax = 100;      int[] age = new int[lenghtMax];     int status = 1;     String next;      int i = 0;      while(status == 1){          if (i >= 100){              System.out.println("You cant register more ages!\n");          } else {                              System.out.println("What the age?");             age[i] = keyboard.nextInt();             i++;              System.out.println("Do you want register other age? y/n");             next = keyboard.next();              if (next == "y"){                  status = 1;              } else {                  status = 0;                 keyboard.close();              }          }      }         System.out.println("Passing Here!"); }   This is my code, where is the error, because it print that message!  Output     What the age? 45 Do you want register other age? y/n y Passing Here!   Why it is printing that message?, the code should get back on the while loop, my while is a normal while!

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


I need to determine, whether an application is allowed to delete a file or directory on file system. For that purpose I currently use the approach, decribed in   .  (I it for both, files and directories)   Unfortunately, the SecurityManager.IsGranted Method is marked as obsolete.   How can I do this check by using the suggested PermissionSet property?

I am writing code that checks for the permission to write to and delete from certain directories. The first is fairly easy. To whit:  FileIOPermission writePermit = new FileIOPermission(FileIOPermissionAccess.Write, _ArchiveHome); writePermit.Demand();   But, how do I do the same for permission to delete from a given directory?


First of all, this answer is related, but not equal to, .  In the final acts of the HP story, we learn that wand ownership plays a great part. If a wizard uses a wand that does not belong to him, his power is greatly diminished.  Now, a wand belongs to a certain wizard and will change allegiances if the wizard is killed or disarmed by another (for example, Draco disarming Dumbledore). However, we also find out that a wand will change allegiances even when it was not directly involved in the fight that causes it to shift. For example, when Harry disarmed Draco, Draco did not have the elder wand in hand. Still, because Draco was the owner of the elder wand, and Harry defeated him, Harry became the new owner.    Now, this leads me to believe that the rule is      If a wizard is disarmed by another wizard, the second wizard becomes the owner of the first wizard's wands.   This, however, is horrible. This rule means that whenever I disarm someone, I am now the owner of his wand, and there is no way for him to get his wand back without me losing my wand. My wand and his are now locked to have the same owner for eternity. Even worse, if I'm a defence against the dark arts teacher and I am teaching a class to perform the Expelliamus spell, there are bound to be some succesful spells cast, and therefore half of my students will lose ownership of their wands. Probably, after a couple of fights, there will be a handful of students who own 10 or more wands each!  Am I missing some rule here? How is it possible in the HP universe that anyone still has ownership of their wand?

In the seventh book (and the 7th & 8th movie) of Harry Potter, it shows that a wand doesn't belong to a person anymore, or loses its loyalty if another witch or wizard disarms or defeats them.  Given that, why don't more children from earlier films and novels have to buy new wands? It shows students being disarmed many times.  Why was the disarming wand rule only valid in the 7th book?


I have to calculate the following limit   $$\lim_{x\rightarrow -\infty} \sqrt{x^2+2x+2} - x$$  it is in un undeterminated form.   I tried to rewrite it as follows:  $$\lim_{x\rightarrow -\infty} \sqrt{x^2+2x+2} - \sqrt{|x|^2}$$  but seems a dead road.  Can anyone suggest a solution?  thanks for your help

This is being asked in an effort to cut down on duplicates, see here: , and here: .    What methods can be used to evaluate the limit $$\lim_{x\rightarrow\infty} \sqrt[n]{x^{n}+a_{n-1}x^{n-1}+\cdots+a_{0}}-x.$$  In other words, if I am given a polynomial $P(x)=x^n + a_{n-1}x^{n-1} +\cdots +a_1 x+ a_0$, how would I find $$\lim_{x\rightarrow\infty} P(x)^{1/n}-x.$$  For example, how would I evaluate limits such as $$\lim_{x\rightarrow\infty} \sqrt{x^2 +x+1}-x$$ or $$\lim_{x\rightarrow\infty} \sqrt[5]{x^5 +x^3 +99x+101}-x.$$


Very similar to the situation in this problem:  but I don't have enough reputation to comment so I'm asking here again. The NN I implemented has 9 inputs, 15 hidden units in 1 layer and 1 sigmoid output. The dataset I was using is about (1) if the annual income of ~50K people $\geq$ or $<$ a certain amount and (2) their education, gender, ethnics, etc (total raw features < 20). I tried altering the regularization coefficient, no. of iterations, adding 1 more hidden layer (a lot slower smh) and even tried swapping the training and test sets but the 0-1 accuracy always topped at around 83%. Is the networks underfitting my data? What else can I do to improve my NN? Straightforward logistic regression gives around 81% accuracy, so I bet NN is the way to tackle this prediction problem. Btw, yes, I'm learning this topic from Prof. Andrew Ng as many others did.

I'm training a neural network and the training loss decreases, but the validation loss doesn't, or it decreases much less than what I would expect, based on references or experiments with very similar architectures and data. How can I fix this?    As for question        to which this question is inspired, the question is intentionally left general so that other questions about how to reduce the generalization error of a neural network down to a level which has been proved to be attainable, can be closed as duplicates of this one.  See also dedicated thread on Meta:


I can ssh into a Linux node on the cloud with root.  I've created another user, web, and I want to add my ssh keys to that user.  Here's what I've tried so far (as root):  mkdir -p /home/web/.ssh cp ~/.ssh/authorized_keys /home/web/.ssh/authorized_keys chown web /home/web/.ssh chgrp web /home/web/.ssh chown -R :web /home/web/.ssh chmod -R g+w /home/web/.ssh find /home/web/.ssh -type d -exec chmod g+s '{}' \; systemctl reload sshd   I'm pretty sure I'm over-setting the permissions but regardless I still can't ssh into the server as the web user.  Box is Fedora 21 on Digital Ocean.    What am I missing?

It took me hours to solve this SSH problem with one of my class accounts on my school's servers.    I couldn't ssh into one particular class account without entering my password, while passwordless authentication worked with my other class accounts. The .ssh/ directory and all of its contents had the same, correct permissions as the other class accounts.   Turns out the problem was the permissions set on my own home directory. Passwordless authentication did not work when the permissions on my HOME directory were set to 770 (regardless of the permissions set for .ssh/), but it worked with permissions set to 755 or 700.   Anyone know why SSH does this? Is it because the home directory permissions are too permissive? Why does SSH refuse to authenticate with the public/private keys when the home directory is set more permissive than 700?


How do you choose what pronoun to use "It" or "They" if "They" is also used as a gender-free singular? Is there no any logic?  It's quite full up this year. They are quite full up this year.  Do these sentences have absolutely the same meaning and no any difference?

Why here is used "they" instead of "it" or "there" for example? What does "they" mean here?  "Can we go to Polseath as usual?" "I'm afraid not," said his mother. "They are quite full up this year."


I have used com.sun.org.apache.xerces.internal.impl.dv.util.Base64 package for the purpose of  encoding decoding of strings. But I want to use java.* package for encoding and decoding instead of com.sun.apache.* package.   Can you please suggest an appropriate java.* package?

I have an image that is Base64 encoded. What is the best way to decode that in Java? Hopefully using only the libraries included with Sun Java 6.


Is there any risk or disadvantage to set normalize=True when using ridge, lasso or elasticnet or does it only have benefits? And what is the impact on the range of alpha if it is set to True, does it even make sense to have variables in different units and apply those models without normalizing them? Thanks for clarification!

I am aware it is common practice to standardize the features for ridge and lasso regression, however, would it ever be more practical to normalize the features on a (0,1) scale as an alternative to z-score standardization for these regression methods?


I need to be able to select which version of IE11 I run (32 or 64 bit) on my 64-bit Windows 7.  I've tried running it from "Program Files" and "Program Files (x86)", but the "bittnes" is always the same. If Enhanced Protected Mode is enabled IE always runs in 64-bit, if it is disabled IE will always run in 32-bit mode.

I need to run IE 10 in 32-bit mode on 64-bit Windows 7 Enterprise N.  When I run IE 10 from "C:\Program Files (x86)\Internet Explorer" I can see in task manager that I have only one process "iexplorer.exe" and no process "iexplorer.exe *32".  I have an application with an ActiveX that is supported only on 32-bit, and the application can't be loaded on 64-bit mode.  Is there a way I can force IE10 to run in 32-bit mode?


Heres the scenario: I have invested through bitcoin to a certain company but the thing is endless payments were being asked and i have complied with them. A few days i received from a certain bank named hpsbank(i dont even know where it is located) asking me for a COT (cost of transfer) of $3500. The account was on my name and they gave me my account name and my password. I was a bit hesitant because their website seemed to be legit but the cons was they dont have a contact number and ive googled about it they are not registered with BBB and FDIC. Now here are my questions i hope you can help me shed light on this. Questions:  Is there really what they called a cost of tranfer between international banks? If ever these are not legit, where can i possible file a complaint to get my money back?  Thank you.

I was marketed by a lady online on some investment packages in bitcoin. ($200 to become $2500 in one week of trade). I indicated interest in this. She took me to a trading website to sign up.  I deposited $200 at the start. After trading for 2 days with earnings, they called me to upgrade the account with $450 which I did. They then traded for 1 week and the account balance became $6786.    I requested to withdraw $6000 from my account and they told me to bring a COT fee of $1200 to complete my withdrawal.  Please help me do a background check on them. Are they real or fake? Check the registration of the company if it is real. The marketer told me the company will pay her from the COT fee.


I have written a test document to illustrate the strange behaviour I have encountered. When I compile the code, it indents the paragraph on the first page differently from the second paragraph but when I skip to the third page, the indentation matches the first page. Please help. My code is below:   \documentclass[11pt,twoside]{article} \usepackage{apacite} \usepackage{graphicx} \usepackage{subcaption} \setlength{\parindent}{0pt} \begin{document} %\nocite{*} % use if we want to see a list of all references  %\input{title_page} % \input{abstract} % \input{table_of_contents} % \input{introduction} \section{dude}  \par sdfdsflsgssdfsd \newpage \par sfsdfsfsfsdfsfsd \newpage \par sfsdfsdfsfsdfsdfs \newpage  %\input{background} % \input{research_questions} % \input{approach} % \input{related_work} % \input{thesis_outline} % \input{project_requirements} % \input{timeline} %\input{references}  \end{document}  %%% Local Variables:  %%% mode: latex %%% TeX-master: t %%% End:   Here is a  to the document that gets produced:

I'm very new to latex, and I've noticed that using a book class causes the text on one page to be on the right and then left on the next and so on. I'd like for it to all to be on the left or centered. How can I change this?


How can I set Google Chrome as the default browser? If I set it in the browser settings, nothing happens. The browser says it's default, but in preferred applications in Gnome, there's only Firefox to choose from. Clicking any link i.e in Thunderbird opens a blank Firefox window, not with the link embedded. Can I set the  default browser in dconf2 or any configuration file?

despite several attempts at making Google Chrome work as my default browser I simply cannot.  I've read countless threads on the internet, checked mimeapps.list and so on, tried about anything, from simple system configuration by going to settings and change as the default browser there, which, for some odd reason, won't allow me to set a default browser, to more advanced terminal scripting.  This is a clean install of Ubuntu 12.10 x64 bit updated to the latest version including kernels.


I'm making a Minecraft server on Minecraft education edition; more like a multiplayer server. Anyway, I want to know how to make the blocks in spawn unbreakable to everyone. I've tried to find my answer on YouTube and the Internet and didn't really find much.

So on my multiplayer server on Minecraft Education Edition I can't seem to figure out how to make the blocks in spawn unbreakable. I know adventure mode fixes that but it's a survival world. I don't want them in adventure, so how do I make the blocks in spawn unbreakable?


Ironically, someone offered this correction:   Irregardless is a word commonly used in place of regardless or irrespective, which has caused controversy since the early twentieth century, though the word appeared in print as early as 1795. Most dictionaries list it as nonstandard or incorrect usage, and recommend that "regardless" should be used instead  Further down in the same thread, they asked, "Why do fools like you keep forgetting...", to which I replied, "Why do fools such as you keep insisting..."  So, who got it right?   Am I over-extending the lesson of my mother's pet peeve, i.e. she always corrected the TV in the '50-60s whenever she heard "Winston tastes good like a cigarette should" which properly said would have been "Winston tastes good, as a cigarette should".   Of course, today that's not seen on TV, having been replaced by "Smoking [Winston] causes lung cancer, as smoking any cigarette would".

This one never ceases to confuse me. When to use 'such as' and when to use 'like' while giving examples? Is there any clear rule?        Metros like Mumbai, Delhi and Karachi are unsafe after dark.    Metros such as Mumbai, Delhi and Karachi are unsafe after dark.       (Before anyone points out, Delhi and Karachi are unsafe round-the-clock, but it's just an example.)


When I do exercises, I always use for loops: for(int i = 0; i < n; i++) But sometimes I got wrong with them, I have tried in many ways to fix, but it ran only when I turn the i++ in for loop to ++i. I wonder when can we use i++ and when ++i?

In C, what is the difference between using ++i and i++, and which should be used in the incrementation block of a for loop?


Hii I have created a website with the help of community builder of salesforce and used webmasters to display it in the Google search list.  Previously I was getting this message :  Now after 2 days of creation of this website in webmasters I am getting the below message:    But still I am not able to see my website in the Google search page whenever I type any keyword related to the website  This is the first time my team is using webmasters .How much more time will it take for my website to be visible in the Google search page. Please guide me.Thanks in advance

This is a general, community wiki  question and answer pair intended to address any questions   concerning the reasons a site or specific site contents do not appear   in search engine results.      If your question was closed as a duplicate of this question and you   feel that the information provided here does not provide a sufficient   answer, please open a discussion on .   My site (or specific pages on my site) is not appearing in search engine results.  Why isn't my content indexed and what can I do about it?


We want only the real 3rd root. By calculation, $[\sqrt[3]{\sqrt 5 +2}-\sqrt[3]{\sqrt 5 -2}]^3= 4-3[\sqrt[3]{\sqrt 5 +2}-\sqrt[3]{\sqrt 5 -2}]$  Therefore, the answer is a root of  $t^3=4-3t$ , which obviously has the real solution $t =1$.   But I want another way of showing $\sqrt[3]{\sqrt 5 +2}-\sqrt[3]{\sqrt 5 -2} =1$, maybe by using simple algebraic formulas.

Why $\sqrt[3]{{2 + \sqrt 5 }} + \sqrt[3]{{2 - \sqrt 5 }}$ is a rational number?


I know that, in theory at least, they do. However, I was wondering if there has been any experimental confirmation of this, or any other reasons for perhaps thinking that they do not interact via the gravitational force.

If neutrinos (or any other particles) wasn't affected by gravity that would contradict the general theory of relativity. I'm convinced that the postulate of the equivalence between inertial mass and gravitational mass is adequate, but not totally convinced that it is the truth.   From my dialectical point of view there are no total unity. In every distinction there is a gap to explore. What is supposed to be identical will be found split complex when examined more closely.  And therefor I would like to know if it's experimentally verified that the neutrinos are affected by gravity?


Ooh, Shiny!       Flag a question for closing, cast a close, delete or reopen vote on a question. You don't have to be the last vote, and hammers work.   (taken from )  And this is the Ethereum (Bitcoin's rival) logo:    Every time I see that hat, it remembers me of the Ethereum logo. Is this supposed to be an advertisement for the Ethereum Stack Exchange? If not, what is it supposed to be?

Inspired by a , here's a list of the 'etymology' for the  hats. For pictures and a list of criteria, see  instead.  The list is a community wiki; feel free to edit it if you have more information about a hat. If you like to do some research, most hats have been featured in earlier editions, so you might be able to find more information in old Meta Stack Exchange questions.


I derived this sum from a problem I have been working on. Somehow I don't know how to proceed. I only know some basics like $\sum\limits_{k=0}^{n}\dbinom{n}{k} = 2^n$. Meanwhile I am reading the related topics trying to derive a formula. But it's like shooting in the dark.

I am trying to prove this binomial identity $\sum_{r=0}^n {r {n \choose r}} = n2^{n-1}$ but am not able to think something except induction,which is of-course not necessary (I think) here, so I am inquisitive to prove this in a more general way.  The left side of an identity occurs while solving another problem (concerning binomial theorem) so I am more interested in deriving the right side from the left side, else I have to remember it now onward.  EDIT: I am more interested in an algebraic proof rather than combinatorial argument or something involving calculus (however I liked  and  solution), hence I am removing the combinatorics tag.


This has happened to multiple applications so far, i'm not sure what causes it, but it seems to happen after force quitting (sometimes).  First, you force quit it, and it does, but the dock shows that it is still open, but not responding. If you go to activity monitor, it does not show up. When you try to use the killall command by name, it tells you "No matching processes belonging to you were found". If you drag the file location into terminal, it still does not work. Deleting (using the rm command, as moving to trash does not work as finder claims the application is running) and reinstalling does not do anything, so i believe it has to do with the dock, or something else on the mac, not the application itself.  OS X Yosemite Version 10.10.3  Edit:  My guess as to what might've happened is the application quit, but the computer never got any indication that it did for whatever reason, so telling it to quit does nothing, but you're not allowed to open an already open application, so you can't open or close it.  Things that do not work:  Terminal : killall Dock   Terminal : killall Finder  Applescript : tell application "(application name)" to activate  Finder Menu : Relaunch

I've been encountering an extremely annoying problem since I upgraded to Yosemite. FCPX (but I've been having reports of this problem on other computers with finder.app and safari.app) sometimes will crash on exit (with no detectable log trace) and its icon will remain in the dock with the usual "this application is not responding" menu warning. Force quit won't work Rebooting can only be done the hard way because the stuck app is preventing a soft one yet no single process regarding FCPX is listed when in the activity monitor nor there is one in psaux. No zombie processes to be found; computer performance is fine. If I open an FCPX library, I'll get a dialog stating that "The application "Final Cut Pro" is not open anymore", which is quite irritating q: I'm on a MBP Retina early 2013 15' Does anybody have the slightest clue what's going on here?


You have a six sided dice. You roll the dice and decide if you want to stop and keep the current value as your result. If not you try again. You can at most throw the dice n times. If you throw it n times you have to keep the last result.  What is the optimal strategy to get the highest expected result? How to proof that this is the optimal strategy?  Example (n=3): Strategy is "Stop if you have a 5 or better". Applying this strategy you would throw 3 5 and have a result of 5. Or throw 4 1 2 and have a result of 2 as no more throws are available.

There's a question in my Olympiad questions book which I can't seem to solve:     You have the option to throw a die up to three times.  You will earn   the face value of the die.  You have the option to stop after each   throw and walk away with the money earned. The earnings are not additive. What is the expected payoff of this game?   I found a solution  but I don't understand it.


I am asked to solve the following  Let G be a finite group with $p^r$ elements, where p is prime. if G acts on the finite set S with N elements and $(p,N)=1$, prove that there exists $s\in S$ such that $g*s=s,\forall g\in G$  I am able to get that $\sum_{g\in G}I(g)>0$ but I don't see how to convert that into $I(g)>0, \forall g\in G$

$G$ is a p-group and $S$ is a set that $G$ acts on. p does not divide $|S|$. Why is there at least one element $a\in S$ such that $|O(a)|=1$, or in other words, $G_a=G$?  I tried to ask this question yesterday but did not word it right, so the one who helped me claim that this part is clearly true and I really do not understand why, and I couldn't get a straight answer for the past day.   Any of you are welcome to vote to delete this question (after some discussion with me about the problem I hope), but I just really want to know why it is "clearly true, because I still couldn't reason it right.


Minor bug, but if you get a notification for a new badge the icon used for the badge will be the one for the site you are currently on, not the one where the badge was earned.     The cause of this is the site-wide standardized css file, which means dynamically resolving the badge for each site might be a little complicated and possibly not worth the effort.

It's so cool that the notification reminds you of the colour of badge you've earned. But I am a little puzzled by the symbols:      Is it feasible to use the symbol from the earned site? At the moment it uses the symbol from the site I happen to be on (as you can see by looking to the left of the dropdown in each case.)


I'm attempting this problem:  Rocket undergoes constant acceleration from rest until it reaches a speed of 0.9c. The astronaut in the rocket feels a constant "induced gravity" of 1g. How long does it take the rocket to reach constant velocity in the inertial frame? How about from the reference frame of the rocket?  For the inertial reference frame I did this:  $$v(t)={a_0t\over {\sqrt{1-{v^2\over c^2}}}}$$  $a_0$ is the proper acceleration, which is $9.8 m/s^2$, and $v=0.9c=0.9 \times(3 \times10^8 m/s)$  $$0.9 \times(3 \times10^8 m/s)={9.8m/s^2t\over {\sqrt{1-{0.9^2}}}}$$ $$t=1.2\times10^7s=0.38yr$$  To calculate how much time it took from the reference frame of the rocket I did:  $$d\tau=dt\sqrt{1-{v^2\over c^2}}=0.38yr\sqrt{1-0.9^2}=0.1649yr$$  Where $d\tau$ is the proper time.  I know this is wrong because I used an online calculator (), and it says that the intertial frame (Earth) says it takes $2$ years, not $0.38$ years. And that the rocket says it takes $1.4262$ years, not $0.1649$ years.   What am I doing wrong?  Edit: The first equation I found in my textbook for motion under a constant force. I assumed that the force would be constant because it's an induced gravitational force that is said to be constant. I set $v(t)$ equal to $0.9c$ because that's the speed it will be at time $t$ which is what I'm looking for.   I know that I can't use the equations for constant velocity because here the velocity is not constant, the acceleration is. I think it may not be working for me because $v(t)$ is not equal to $v$. However, I'm not sure how to find $v$ here because it varies.   I visited the , but it was difficult to follow.   Is this not working for me because the $v$ isn't constant?   Edit 2: The Wikipedia page was difficult for me to follow because it involved hyperbolics. We haven't talked about hyperbolic motion in detail in my class, it was only mentioned once, very briefly. So I thought that there could be a way to do this problem without using $\cosh$, $\sinh$ and $\tanh$

I have found these two formulas:  $v = at + v_0$  $x = \frac{1}{2}at^2 + v_0t + x_0$   a is the acceleration v is the velocity x is the position t is the time $v_0$ is the initial velocity $x_0$ is the initial position   The problem is that with an acceleration of $10$ m.s$^{-2}$ (for example) the object would surpass the speed of light in $3 \times 10^7$ s = $11$ months and $11$ days, which should not be possible.  Is there some other formula that gives the position of an object depending on its acceleration and on the time, but which works and does not allow the speed of the object to surpass the speed of light?


Exercise: Let $(f)_{n\in\mathbb{N}}$ be a sequence of functions such that $f_n\to f$a.e(almost everyehere) and there exists $g$ integrable such that $|f_n|\leqslant g$a.e   for all $n\in\mathbb{N}$. Prove that $f_n\to f$ almost uniformly.   I think I can apply the following theorem:     Ergoroff Theorem:   Consider $E\in\mathscr{F}$(sigma-algebra), and $E\in\Omega$ defined on a measure space $(\Omega,\mathscr{F},\mu)$. Suppose $\mu(E)<\infty$, and $\{f_n\}$ is a sequence of measurable functions on $E\to\mathbb{R}$ which are finite almost everywhere and converge almost everywhere to a function $f:E\to\mathbb{R}$ which is also finite almost everywhere. Then $f_n\to f$ almost uniformly in $E$.   I now that $f_n\to f$ a.e so $\lim_{n\to\infty}f_n(x)=f(x)\forall x\in E$, But to apply Ergoroff theorem I need to prove that $\mu(E)<\infty$ or $\mu(\Omega)<\infty$. I know by the Dominated convergence theorem that $\lim_{n\to\infty}\int |f_n-f| d\mu=0$ but I cannot see how shall I prove from there that $\mu(E)$ or $\mu(\Omega)$ are limited.  Question:  Can someone provide me any help?  Thanks in advance!  Note:$f_n$ does not necessarily converge to $f$ uniformly. So the question is not a duplicate.

I want to prove that if I omit the fact that $\mu (X) < \infty$ in Egorov theorem and place instead that our functions $|f_n| <g$ and $g$ is integrable, we still get the result of Egorov's theorem.  Fix $m$ a natural number.  I took $ w_{n} = |f_n-f|$ and thus by DCT $\int |f_{n} - f|$ goes to zero.  Then I took $\bigcup_n {( w_{n} \geq 1/m)}$. I need its measure to be finite. Its measure is less than the sum of the measures of each $ w_n\geq 1/m)$ varying $n$, and by Tchebychev, this is less than $m\int|f_{n} - f|$.  But I got stuck here.  Any help is appreciated. Thanks!


I was trying to join the new Emacs site.   I saw an apparently strange behaviour during sign up.      If try to sign up via Google (being logged to it), I get a prompt asking whether I accept SE to see my mail and some basic profile info. All I have to do is to click accept.   If try to sign up using Stack Exchange (being logged to it), I am asked a (new) email address, name, password, etc.   What for? I have already a network profile, why not asking me to use that? I don't remember when I signed up last time, but it was much simpler: just granting permission to SE Open ID.

Using the Stack Exchange login, why do I have to enter my password again and again to log in? Wasn’t the whole purpose of OpenID to do away with this?  This doesn’t even only happen when visiting a new Stack Exchange site – it also happens for sites where I already have an account but which I don’t visit regularly. Here’s what I mean:    Of course I don’t remember my password (it’s a long random string). And so I have to go to my password manager and manually copy the password from openid.stackexchange.com’s account into the login form. – And incidentally, this is what my password manager looks like now:    (And, by the way, those are the only entries in my keychain so far, but by far not the only SE sites where I have an account.)  … I feel that this defeats the purpose of site-wide login and OpenID. In the olden times when MyOpenID was still working properly, I’d simply enter my OpenID on the login form, and the software would take care of the rest – namely, redirect to the OpenID service, (automatically) verify that I was authorised to use it, and redirect back to the original website, having logged me in. It was literally one button click for me. It’s substantially more work now, and I’d like to understand why this regression is necessary.  (Note: of course once a site’s password has landed in my password manager I (probably?) won’t have to enter it again. But still: wasn’t site-wide login and OpenID supposed to solve this already?)


So as I understand it: If you hit a wall at twice the speed you hit four times as hard?  I often ask people this and everyone says "at twice the speed you hit twice as hard".   $K=\frac{1}{2}mv^2$ is very counter intuitive. I have read an explanation that seems to say gravity is acceleration and that's where the squared comes from.  Do we have anyway of knowing if the kinetic energy of an object outside of a gravity field is linear or quadratic? Could the gravity field somehow match the acceleration to give the $v^2$  Bonus question: If you get pulled over for speeding should you ever ask the policeman why kinetic energy is quadratic instead of linear?  $K=\frac{1}{2}mv^2=$($300) dollar fine where I live.

As  says:     [...] the kinetic energy of a non-rotating object of mass $m$ traveling at a speed $v$ is $\frac{1}{2}mv^2$.   Why does this not increase linearly with speed? Why does it take so much more energy to go from $1\ \mathrm{m/s}$ to $2\ \mathrm{m/s}$ than it does to go from $0\ \mathrm{m/s}$ to $1\ \mathrm{m/s}$?  My intuition is wrong here, please help it out!


Please help about below error. I don't know how to resolve below error. I will try several ways follows from searches and drupal.org forums. But error still comes back.  Please check the below image everything I mentioned in that. wamp versions, windows versions.

Recently I started getting an error every time I try and add a content no matter what type.  This is the error that shows up in the browser:     Additional uncaught exception thrown while handling exception.        Original   PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT COUNT(cid) FROM {comment} WHERE status = :status; Array ( [:status] => 0 ) in comment_count_unpublished() (line 313 of /Applications/MAMP/htdocs/modules/comment/comment.module).        Additional      PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: INSERT INTO {watchdog} (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9); Array ( [:db_insert_placeholder_0] => 1 [:db_insert_placeholder_1] => php [:db_insert_placeholder_2] => %type: !message in %function (line %line of %file). [:db_insert_placeholder_3] => a:6:{s:5:"%type";s:12:"PDOException";s:8:"!message";s:154:"SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT COUNT(cid) FROM {comment} WHERE status = :status; Array ( [:status] =&gt; 0 ) ";s:9:"%function";s:27:"comment_count_unpublished()";s:5:"%file";s:56:"/Applications/MAMP/htdocs/modules/comment/comment.module";s:5:"%line";i:313;s:14:"severity_level";i:3;} [:db_insert_placeholder_4] => 3 [:db_insert_placeholder_5] => [:db_insert_placeholder_6] => ; [:db_insert_placeholder_7] =>  [:db_insert_placeholder_8] => 127.0.0.1 [:db_insert_placeholder_9] => 1338336955 ) in dblog_watchdog() (line 154 of /Applications/MAMP/htdocs/modules/dblog/dblog.module).   I also get the following error in my php error file:     PHP Fatal error:  Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away' in /Applications/MAMP/htdocs/includes/database/database.inc:2136        Stack trace:   0 /Applications/MAMP/htdocs/includes/database/database.inc(2136): PDOStatement->execute(Array)   1 /Applications/MAMP/htdocs/includes/database/database.inc(664): DatabaseStatementBase->execute(Array, Array)   2 /Applications/MAMP/htdocs/includes/database/database.inc(2315): DatabaseConnection->query('SELECT expire, ...', Array, Array)   3 /Applications/MAMP/htdocs/includes/lock.inc(167): db_query('SELECT expire, ...', Array)   4 /Applications/MAMP/htdocs/includes/lock.inc(146): lock_may_be_available('theme_registry:...')   5 /Applications/MAMP/htdocs/includes/theme.inc(447): lock_acquire('theme_registry:...')   6 /Applications/MAMP/htdocs/includes/bootstrap.inc(427): ThemeRegistry->set(Array)   7 [internal function]: DrupalCacheArray->__destruct()   8 {main}         thrown in /Applications/MAMP/htdocs/includes/database/database.inc on line 2136   I am having a little trouble deciphering these error messages. Could anyone help me understand what's going on here?


I'm a newbie to Ubuntu. My laptop runs Ubuntu MATE and I want to have remote access to it (like when I'm not at home). Can I access it from another machine running Windows? How?

I have some user accounts in my Ubuntu 10.04 and I want them to login from all over the world and access their data using Internet and of course I want any of my users to be able to access only their own user and to be able to change data.  What should I do? Are there any remote desktop apps?


In an iPhone app, I am having a UITextField which needs input as numerics, so I am passing the Keyboard type as UIKeyboardTypeNumberPad. It works but there is no return or Done button, so how can I hide the keyboard.  Code for reference is:  textDriverAge.delegate=self; textDriverAge.keyboardType=UIKeyboardTypeNumberPad; textDriverAge.clearButtonMode = UITextFieldViewModeWhileEditing; [textDriverAge setReturnKeyType:UIReturnKeyDone];// UIReturnKeyNext]; textDriverAge.enablesReturnKeyAutomatically=TRUE;   I have handled the UITextfield events like:  - (BOOL)textFieldShouldReturn:(UITextField *)textField {   if(textDriverAge == textField) {     [textDriverAge resignFirstResponder];      //[tglDropInDropOff becomeFirstResponder]; }  }   Guide me how to hide the keyboard.

There is no "Done" button on the number pad. When a user finishes entering numeric information in a text field, how can I make the number pad disappear?  I could get a "Done" button by using the default keyboard, but then users would have to switch to the numeric keys in order to input numbers. Is there a way to show a "Done" button on the number pad?


I understand the PCA method in a following way:  0) I have a cloud of dots in ND space   1) I should find a vector which gives me a maximal variance when dots are projected on this vector.  2) I should find the second vector orthogonal to the first, which will explain the maximal possible variance.  And so on..  My question is - if I would use the plane, defined by first and second principal components, will it be the plane, which explains the maximum possible variance?

Suppose we have a covariance matrix $C$. Define the eigendecomposition, $C = Q^{-1} \Lambda Q$ and some other arbitrary basis $C = B^{-1} D B$.  Define $V_\text{PCA} = \text{diag}(QCQ^{-1})$ and $V_B = diag(BCB^{-1})$, and assume they're both sorted by magnitude. Define $T_\text{PCA} = \text{sum}(V_\text{PCA})$ and $T_B = \text{sum}(V_B)$. Is it possible that $V_\text{PCA}[i] / T_\text{PCA} < V_B[i] / T_B$ for $i = 0$? If so, how is this possible? Doesn't it violate the idea that PCA initially finds the basis vector with maximum variance?  I can understand how the inequality holds for $i > 0$, due to the orthogonality constraint of PCA which may not result in the "optimal" vectors being found in the variance-explained sense.  I'm trying to figure out if there's an error in my code, so please forgive the convoluted notation, but I want to be as clear as possible about what I'm seeing.


I want to launch a sleep in the background,  bg sleep 100   but sleep 100 seems not to exist, is there a mistake? Do I have to launch a sleep before? It seems odd, as far as I would have no more control...

This is the output:   [USER@SERVER ~] ping localhost PING localhost (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.037 ms 64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl=64 time=0.024 ms 64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl=64 time=0.030 ms 64 bytes from localhost (127.0.0.1): icmp_seq=4 ttl=64 time=0.026 ms 64 bytes from localhost (127.0.0.1): icmp_seq=5 ttl=64 time=0.026 ms ^Z [1]+  Stopped                 ping localhost [USER@SERVER ~] jobs [1]+  Stopped                 ping localhost [USER@SERVER ~] bg %1 [1]+ ping localhost & 64 bytes from localhost (127.0.0.1): icmp_seq=6 ttl=64 time=0.034 ms [USER@SERVER ~] 64 bytes from localhost (127.0.0.1): icmp_seq=7 ttl=64 time=0.030 ms 64 bytes from localhost (127.0.0.1): icmp_seq=8 ttl=64 time=0.032 ms  [USER@SERVER ~] ^C [USER@SERVER ~] ^C [USER@SERVER ~] 64 bytes from localhost (127.0.0.1): icmp_seq=9 ttl=64 time=0.031 ms ^C [USER@SERVER ~] 64 bytes from localhost (127.0.0.1): icmp_seq=10 ttl=64 time=0.031 ms 64 bytes from localhost (127.0.0.1): icmp_seq=11 ttl=64 time=0.028 ms ki64 bytes from localhost (127.0.0.1): icmp_seq=12 ttl=64 time=0.030 ms ll %64 bytes from localhost (127.0.0.1): icmp_seq=13 ttl=64 time=0.031 ms 1 [1]+  Terminated              ping localhost [USER@SERVER ~]    of:  1) I start to ping localhost 2) CTRL+Z 3) bg %1 4) CTRL+C doesn't work.  5) I have to type "kill %1" to kill it..   What is the real-life use of the "bg" command? Where is it used in the real world?


I have bought a relatively new Asus N550JV notebook, which has two graphic cards and uses a technology called .  This is the hardware information:  $ lshw -C display   *-display UNCLAIMED             description: 3D controller        product: GK107M [GeForce GT 750M]        vendor: NVIDIA Corporation        physical id: 0        bus info: pci@0000:01:00.0        version: a1        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: memory:f6000000-f6ffffff memory:e0000000-efffffff memory:f0000000-f1ffffff ioport:e000(size=128) memory:f7000000-f707ffff   *-display        description: VGA compatible controller        product: 4th Gen Core Processor Integrated Graphics Controller        vendor: Intel Corporation        physical id: 2        bus info: pci@0000:00:02.0        version: 06        width: 64 bits        clock: 33MHz        capabilities: msi pm vga_controller bus_master cap_list rom        configuration: driver=i915 latency=0        resources: irq:47 memory:f7400000-f77fffff memory:d0000000-dfffffff ioport:f000(size=64)   Distribution information:  $ uname -a Linux thomas-N550JV 3.8.0-30-generic #44~precise1-Ubuntu SMP Fri Aug 23 18:32:41 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux   What I want is to use the nvidia card as my default graphics adapter. Is this possible?  What I've tried:   installing nvidia-319-updates installing xserver-xorg-video-intel using the  PPA and installing the above two drivers, independently and together. using the

I am considering buying a Dell XPS 15 laptop. The laptop has a Nvidia 420m card which should work with Linux but I keep reading that the Nvidia Optimus technology isn't supported on Linux. I am not really interested in switching from Nvidia to Intel to save power but need to know that the Nvidia card will in fact work if I installed Ubuntu.  If anyone has experience using a Nvidia card with Optimus technology or even better the exact laptop in question (Dell XPS 15 with 1GB NVIDIA® GeForce®  GT 420M) it would be great.  A major problem holding people back from adopting Linux is this sort of hardware issue. I am a long term Ubuntu user and supporter who can't afford to make a mistake with a purchase like this. I don't want to spend £500+ to find I have no graphics acceleration because Windows 7 is not an option.