For representations over an algebraically closed field one can formulate Schur's lemma in the following form:     Every endomorphism of irreducible representation is of the form $\lambda\cdot id$   I wonder, if the converse is true, i.e if all endomorphisms of representation are scalar then it is irreducible. It's easy to see that such representation must be indecomposable, but what about irreducibility?(case of non-algebraically closed field is also interesting)

I am interested in the converse of the following form of Schur's lemma:  Lemma. (Schur) A group $G$, a $\mathbb{C}$-vector space $V$ and a homomorphism $D : G \rightarrow \operatorname{GL}(V)$ are given. Suppose that $D$ is a irreducible reprsentation. If a linear map $T : V \rightarrow V$ commutes with $D(g)$ for all $g \in G$, then $T$ is some scalar multiple of the identity operator.  Edit) What I want to prove or disprove is the converse of the above:  Suppose that the representation $D : G \rightarrow \operatorname{GL}(V)$ is reducible. Then there is a linear map $T : V \rightarrow V$ which is not a scalar multiple of the identity such that $T D(g) = D(g) T$, $\forall g\in G$.  When $G$ is a finite group or a compact Lie group, this trivally holds, because every reducible representation of $G$ is decomposable (i.e. fully reducible); if $W \leq V$ is a subspace invariant under $D : G \rightarrow \operatorname{GL}(V)$, then we can find an invariant subspace $U \leq V$ satisfying $V = W \oplus U$, and $T=\pi_W+2\pi_U$ commutes with every $D(g)$ but is not a scalar multiple of the identity. ($\pi$: projection operators)  QUESTION. But what if $G$ is a general group, which admits reducible but indecomposable representations? Does the converse of Schur lemma still hold?


I have two MacBooks (an old one mid 2009 with a 150 GB drive (128 GB used) and a newer from 2011 with a 300 GB drive (30 GB used)) and a 1 TB Hard Disk.   What is the easiest way to move the content of the 2009 MacBook to the 2011 model and the content of the 2011 model to the 2009 model (so that basically the content of the the two MacBooks is swapped afterwards)?

I have a Macbook and an iMac, generally I work on my Macbook, but sometimes I need that information on my iMac. My OS is Mac OSX Snow Leopard.


I have the following code written in .  Since I upgraded the package NuGet SonarAnalyzer.CSharp to the version 6.0.0.2033, I've got this error :  Error S3925   Update this implementation of 'ISerializable' to conform to the recommended serialization pattern.      public class GenericException : Exception {     public GenericException(string message) : base(message)     {         // ...     }      public GenericException(string message, Exception innerException) : base(message, innerException)     {         // ...     } }   Does someone have an idea ?

More specifically, when the exception contains custom objects which may or may not themselves be serializable.  Take this example:  public class MyException : Exception {     private readonly string resourceName;     private readonly IList<string> validationErrors;      public MyException(string resourceName, IList<string> validationErrors)     {         this.resourceName = resourceName;         this.validationErrors = validationErrors;     }      public string ResourceName     {         get { return this.resourceName; }     }      public IList<string> ValidationErrors     {         get { return this.validationErrors; }     } }   If this Exception is serialized and de-serialized, the two custom properties (ResourceName and ValidationErrors) will not be preserved. The properties will return null.  Is there a common code pattern for implementing serialization for custom exception?


I have Ubuntu 12.04 LTS. This morning when I logged into my Ubuntu, after login screen the complete desktop was empty, the only operation I could perform is right-click and open terminal.  What I've tried:   Ctrl+Alt+F1 unity --reset : didn't work From terminal unity --reset : didn't work And from login screen selecting Ubuntu 2D and that also didn't solve the problem.   My laptop is Toshiba SA-60 onboard ATI graphic card with 1 GB RAM.  Please tell me how to solve this problem. I don't want to reinstall Ubuntu as whenever I install a I/O error pops up, forget about that. I don't want to reinstall Ubuntu. Please help.

When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.


I want to print user_picture thumbnail in my page template. I am using the following code in hook_preprocess_html() in my .theme file.  $user = user_load(\Drupal::currentUser()->id()); $style = entity_load('image_style', 'thumbnail'); $variables['user_picture'] = $style->buildUrl($user->get('user_picture')->entity->url());   It's generating a URl but it is showing 404, what could be wrong here?

I am working on customization Node template file in Drupal 8, I added another field to user in admin/config/people/accounts/fields ( my field is field_bio). Now I want to render author image( with specified image style) and field_bio in node template`.  How can I achieve this?


Ha ii,I am doing a Bible application,my requirement is the user write a note or copy some contents in Bible have to sync or share with google doc.Is there any API available for this ?like sharing to Facebook or twitter. How to do this? Thanks in advance.

I've seen a couple of iPhone applications that have the functionality to export data to a Google Apps document or spreadsheet.  I would like to add similar functionality to my iPhone app.  Is there an API for that?  How about the other direction - is there a way to get data (say a CSV file) from a Google Apps spreadsheet?  If there isn't one of those, is there a way to directly import a SQLite dump file in iTunes?  Background: the app I'm writing deals with a large number of records, possibly thousands, and rather than expecting people to enter them on that tiny little keyboard, I'd like to be able to take data entered on a real computer.  Plus, this iPhone app is replacing a Palm app that I already use, which I have entered hundreds of records, but which has the ability to produce a CSV file.


Ever since upgrading to Yosemite 2 days ago my notifications no longer work. I can't even open the notification center by clicking the icon in the menubar. Nothing happens when i click it.  Anyone know what's going on or where to look to further investigate the issue?

I believe I followed the advice here:   Post upgrade to Yosemite, the Notification Center icon shows up in the menu bar, but clicking on it does nothing, as noted by this individual:


A Forbes article -- apparently written by an American -- titled "" has this passage:     The other structural elements of body, alcohol, and sugar can also point to an age-worthy wine. Full-bodied wines, which also tend to be high in alcohol, are more likely to age well, but it’s important that all of that body is supported by acid, tannins, or both. That rich, soft $10 red purchased at the supermarket is easy-drinking now, but without firm tannins or bright acidity, it will not improve at all over time. Sugar can also help a wine age, though the perception of sweetness will diminish through the years.   Assuming this is American English, is there any reason why the verb in the that-clause is not "be" but "is"?  I thought it was only informal BE that would allow "is" in this type of clause.  EDIT  Here, the writer is saying that some cheap reds may lack in tannin or acidity, in which case the strong flavor of such cheap wines is going to diminish over time.   So, I don't think the writer is making a factual statement in the bold clause, but rather is presenting a condition under which full-bodied wines can age well without losing the full-bodiedness over time.

It is necessary for him to do something.   It is necessary that he do something.   I know the second one is subjunctive and I know that it is used for command, demand, etc.  I want to know what difference does it make in the meaning?  Is subjunctive used in spoken language?  Examples:     It is necessary for Tom to arrive at 5.   It is necessary that Tom arrive at 5.


FYI - I'm pretty new to blender. I'm playing around with the sculpting tools and was using the grab / inflate brushes on a UV sphere mesh that I had previously used a subsurf modifier on. It gets this weird spiky pattern near the poles and I can't really seem to smooth it out. Why does this happen and how can I fix it?

My problem is simple. I think that the strange deformations on the top are there because there are so many vertices in one face. How do I fix this while maintaining nice topology?  Although I triangulated the top polygon, the problem still persists.


Hey all I know this question has been asked before, but the other thread has not answered the question I am looking for. I think I found a series representation of $f(x) = \sqrt{x}$, but it uses the double factorial $$1 + \frac{1}{2}(x-1)+\sum_{n=2}^{\infty}(-1)^{n-1}\frac{(2n-3)!!(x-1)^n}{2^nn!}$$  I am fairly sure this representation is correct, but my professor has never introduced us to double factorials so I have a feeling this is not the way he wants us to approach this problem. I have been introduced to binomial series and I feel that might be a better representation, but I am still unsure how to write it as a binomial series, any pointers? Thanks!

I recently learned more about Taylor series, what I called infinite polynomials, and decided to find the Taylor series of $\sqrt{x}$. Of course, because $\frac{d}{dx}\sqrt{x}$ at $x=0$ is undefined, I am actually asking about the Taylor series of $\sqrt{x+1}$. I have found the Taylor series for this, kinda. It is $\sum_{n=0}^∞\left(\left(\prod_{m=1}^n\left(1.5-m\right)\right)\cdot\frac{x^n}{n!}\right)$. My real question is: Can this be made smaller?


Find the limit $$\lim_{n\to \infty}\{{(n!)}^{1/n}\}/n$$  I took exp log but getting answer as 1 but it should be 1/e. Required a nice approach.

I'm trying to find  $$\lim_{n\to\infty}\frac{n}{\sqrt[n]{n!}} .$$   I tried couple of methods: Stolz, Squeeze, D'Alambert  Thanks!  Edit: I can't use Stirling.


Note on Duplicate - This has been marked as a duplicate quite a few times, so can someone link me to a solution which works for me? Because everything I've tried in all the other posts I've found, just hang forever. Thanks.    We have a server which has a mounted NFS share to a server which no longer exists, so this is a line from the mount command on server "t01":  192.168.1.2:/test on /t02 type nfs (rw,vers=4,addr=192.168.1.2,clientaddr=192.168.1.12)  The t02 server no longer exists, it has been completely turned off and removed forever. I want to unmount it but can't seem to get it to work. I've tried the usual things suggested in posts but it's being stubborn!  If I do umount -f -l /t02 it just hangs forever..  So I tried doing an strace on that command:  strace umount -f -l /t02  and I get the following:  close(4)                                = 0 umask(022)                              = 022 getuid()                                = 0 geteuid()                               = 0 readlink("/t02", 0x7fff65ec9fb0, 4096) = -1 EINVAL (Invalid argument) stat("/t02",   Is there anything else I can do to force this to unmount? It's currently stopping me do a df -kh (just hangs if I try it).

I am trying to write a script for such failure scenarios.  In a scenario where maybe, if remote connection is lost, df waits for the remote server to respond (looks like df is hanging). I know I could do a timeout after waiting for some seconds but is there any other way to check that df is hanging and kill it.  Also can I find out which mount point is causing the problem? So that I could try to unmount and mount it again.


I am travelling to Budapest and therefore have a Schengen Visa. I hold an Indian passport and a valid US visa. I'm travelling from Chicago-Heathrow-Budapest and returning by Budapest-Dublin-Chicago.  Would I need a transit visa for UK/Ireland?  UPDATE  Hoping this will help someone someday.   I was not allowed to board my return flight (BUD-DUB-ORD) because I do not hold an overnight Irish Transit Visa. They said I could have transited happily if the connecting flight was in the same day, but because I would have to originally land at 10 PM and catch the connecting flight next morning at 10 AM, I needed a transit visa. Well, I thought it was BS, but couldn't help comply with the rules. I booked another last minute ticket and flew via Warsaw via LOT.

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


I've wondered this for a while. I personally think that System32 would make sense to be the 32 bit Windows OS. But when you have a 64 bit Windows OS, the file system is still called System32. Can anyone explain to me why this is and why Microsoft does it this way?

I don't know about vista. I never used it. I just moved from XP (32 bit) to Windows 7 Ultimate (64-bit). I was expecting c:\windows\system64 directory similar to c:\windows\system32. Why is still entire system is located in system32? Why isn't there any system64 directory?


The title says it all. Why is is true that $n^x > \log(n)$ for $x > 0$?

I'd like to show that for all $\epsilon > 0$, there exists an $N$ such that for all $n \geq N$ the following holds: $n^\epsilon > \log(n)$. I'm having trouble justifying this.   My intuition says this should hold. Writing $n = 2^k$ gives an inequality of the form $(2^\epsilon)^k > k$. This should hold for sufficiently large $k$ (and therefore $n$) because $2^\epsilon > 1$, so the function $(2^\epsilon)^k$ grows much faster than $k$. (This is also the approach described in  question.)   However, I was wondering if there is a more "rigorous" way to justify this inequality.


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   So, I have something like this in my code, I was wondering how do add a click function that grabs the specific div that was clicked?  I thought this would work $('.card-block').on('click', function() { "do something" });  Ok, so I guess I forgot to mention my DOM is being build dynamically, and it's constantly being built dynamically every time the user clicks on a button, or resizes the window.

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


So I was introduced to Tokyo Ghoul by watching the anime. I recently started reading the manga and was surprised when I saw this on the character profile on the back-lid of the front cover of Tokyo Ghoul volume 14 (the final volume before :re):         I know it is implied that Eto is Takatsuki Sen in the anime and manga, but I don't recall anywhere in the anime where it is revealed that Eto/Takatsuki Sen is the One-Eyed Owl. I also don't think I recall reading in the manga that this was the case (until I saw this image).  Did I miss something? Is Eto/Takatsuki Sen the One-Eyed Owl?

In Root A, Takatsuki does seem to be fascinated by Kaneki's name, but,      I didn't at all expect her to be the One-Eyed Owl.   I just looked her up on the  and it says that       she is the One Eyed-Owl as well as the horror novelist.   Is this true only in the manga or is it also true in Root A?


If $x^{x^4} = 4$, what is the value of $x^{x^2} + x^{x^8}$ ?  I can find by trial and error, that $x=\sqrt 2$. But, what is the general process to answer questions like this?

If $x^{x^4}=4$; Then what is the value of $x^{x^2}+x^{x^6}$ ;  I just want a hint like from where should I start. (other than using a trial and error to find that $x=\sqrt{2}$ satisfies this and now just put it in the required equation!!)


I use iCloud's shared photo albums from my iPhone and look at the files from my OSX Photos app on my mac laptop. I would like to know where these files are stored / cached on the file system. I'm able to "import" these files from the shared album and then see them in Finder by looking at at "Photos Library" files in Finder. However, I can't see these files anywhere on my filesystem if I don't "import" them.  Ultimately, I'm trying to use the shared album functionality to create a stream, but cross-post the album on another source (probably Google Photos) automatically for family members who are not on OSX. (I'm aware of the ability to post these albums on iCloud, but am not happy with the generated web album, so I've decided to go down a different path). I'm happy to write a cron job or automator script if necessary to achieve the above.

What is the location where Apple Photos stores Shared photos? I'm looking for the photos that appear under the Shared tab, to view them in the Finder.  My particular reason is that I'd like to enable these photos to be backed up by Google Photos Desktop Uploader. All of my own photos are being synced to Google, but not the ones that are shared with me. If I can find the local copy, I can turn it on in the uploader preferences.


I've searched thesauruses to no avail. I'm hoping to find a more refined way of describing someone as 'disorganized', which to me seems to have a slightly negative connotation. The alternatives I have come across so far seem to be even worse ('chaotic', 'confused' etc.). What I have in mind would be something to conjure up the image of an eccentric scholar, perhaps sort of besieged by books piled on either side in disarray.  The question already posted didn't quite give me what I wanted, since it seemed to be referring to someone who was fond of chaos, not someone who simply can't keep themselves neat. I felt the suggestions given were mostly unflattering as well, which isn't what I'm looking for.

I am wondering if there is a word to describe a person who likes chaos. By this I mean a few specific things:   The person is pleased to hear when chaos is created, or confusion emerges The person will take opportunities to create chaos or confusion The person enjoys taking part in chaotic or disorganized situations.   I can't seem to think of a word to describe the type of person who would act in this way.  I hope this question is clear.  EDIT: Below gbutters sums up nicely:     What I wonder is if there is a word for a generally good-natured person who just likes some good old-fashioned chaos. It seems like any person that thrives on chaos would have to have some extra baggage.


I have been playing around with this and noticed that it worked for a few functions.  Does it work generally?  And does that mean that if $f(z)$ is entire or analytic, it's conjugate won't be since $f(\bar{z})$ isn't analytic?

Is it true that  $ f(\bar{z})=\overline {f(z)}$, Where z is complex?  I think it holds when $f(z)$ is holomorphic since we have $f(z)=p(x,y)+iq(x,y)=p(z,0)+iq(z,0)$ Any help...


The first noncomment line in a legacy crontab file begins with five asterisks:  * * * * * ([a_command]) >/dev/null 2>&1   The authors are gone, so I do not know their intent.  What does all-wildcards mean to (Solaris 8) cron?  The betting here is either run once, run continuously, or run never, which is unfortunately broad.  If you are wondering about the comment line preceding this, it is "Do not delete."  Note: This cron file is working. This question is not a duplicate of a question about broken cron files or cron files which require troubleshooting.

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


I am trying to design a bias controller circuit using . I am unable to find the full schematic of the same. Has any one used  for designing bias circuit? Edit:- I have updated datasheet link

I am using , which is and Bias controller/sequencer. I am using this for Providing gate voltage and drain voltage to the . In the datasheet, it is mentioned that the module with combination of EVM can be used in two applications. Application Option 1: Fixed negative gate biasing with pulsed drain biasing. Application Option 2: Pulsed negative gate biasing with pulsed drain biasing. I am trying to design both applications on a single board. The second option for future use. For the 1st application option, he has mentioned a few pins as No connection and he has used those NC pins on the 2nd application.  The issue I am facing:- They have used voltage followers for providing a low impedance output path for pin number 3(GCO). I have reverse-engineered the Ckt from the below-attached image, but I am unable to identify the voltage follower they have used. Pin number 2 of the voltage follower has been connected to pin number 2 (NC/GCP) of the Module. There has been no description of this pin number. I am guessing these:-  Pin numbers 1 and 4 are connected together and output is provided through them. Pin number 5 is +Ve supply hence connected to GND(Highest +Ve supply)? Pin number 3 is connected to -8V Pin number 2 is connected to pin number 2 of MABC-001000-DP000L, which I am unable to understand.  I have mailed component manufacturer regarding full schematic, till now I haven't heard from them. Can anybody help me with this? Thanks in Advance. Low-resolution pic of EVM. I don't think it helps in any way.   Layout Image


Is there a formula to calculate the dangerousness of amps, and volts? like watts, for example. Watts = Volts x Amps. Generally speaking, you could say wattage takes into account volts, and amps. I am working on a robot. And am using high power motors. I don't want to learn the hard way, by getting shocked. I need a formula, or at least a wattage chart, to see, where, on the dangerousness scale my electrical system is.  If I am touching a 1.2ft wire supplying 12v 80A of electricity, how fatal would that be (both heat wise, and shock wise), or would i be able to feel it at all?

Related:        From what I've heard:   110 V (or 220 V; household voltage pretty much) is dangerous (i.e. can kill you) I think there's consensus on this, no need to try :) 60 V (old telephone lines) is supposedly dangerous (never tried, only heard it once... probably won't try)   From what I know first-hand:   9 V is not dangerous (I've put a 9-V battery on my tongue, nbd... actually it kinda hurt!) 1.5 V can indeed be quite shocking with enough current (fell for one of those "Do you want some gum?" tricks back in high school...), but they sometimes do not use 1.5 V with the low amperage levels, some use a DC motor to vibrate and complete the trick.   So I guess there's two parameters here, voltage and current... but are there rough numbers on how much of each (or in combination, which I guess would be power) would be considered hazardous?  No old telephone lines have always been 48vDC well at least since from 1950s, if your skin is wet you can feel it slightly, like on your forearm.  Now the ring voltage is 90-110vAC with a 2 on 4 sec off cycle (USA).  It will ring your bell but good, should you be touching the wires when someone calls. The ring voltage rides on top of the 48vDC, so its present on the same two conductors that the voice voltage(DC) is on. Luckily it's 4 seconds off will give you a chance to get off the conductors with a scream (of pain).


After upgrading to Ubuntu 18.04, I miss the keyboard shortcut to maximize / unmaximize a window. In 16.04, I pressed <Alt><Space>, and the following menu opened:  Afterwards I pressed x to maximize or unmaximize the referring windows. Every menu entry had a certain key assigned. Thes key assignments seem to be gone in 18.04. How can I activate it again?

On Ubuntu 16.04 LTS I have used simple keyboard shortcut to set property Always on Top (Nautilus window as example):   Alt+Space,    t After next Alt+Space or right mouse click I see that window was set to Always on Top.     In standard Ubuntu 18.04 LTS with GNOME Shell I can press Alt+Space:    but it does not react to t.  Seems to be a real .    How to enable such menu accelerators/mnemonics in standard Ubuntu 18.04 LTS?


SELECT * FROM posts ORDER BY `posts`.`postid` DESC WHERE postid < ".$_POST['last_video_id']." LIMIT 8 ;

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


I have got into system preferences and there is no recents uncheck. How do I stop app icons from sticking in the dock?

Every time I connect my iPhone to my MacBook, the system launches iTunes which I don't use. After I close it, the icon remains in the Dock and I have to right click and remove it. I don't move the icon in the Dock and I don't touch the Dock at all in this process.  Note that I am very aware that applications may be on the dock unless they are fully closed. In this case, not only is the app closed but the Activity Monitor does not list the process running.  Staying in the Dock also happens with other applications after I start them, but not all applications. Skype opened itself on reboot and after closing that application, it remained in the Dock. I also verified it is not listed in Activity Monitor. I removed the option to launch Skype on start and that one won't spin up each time, thankfully. But if I launch Skype manually it has the same behavior, it will place itself persistently into the Dock after it is closed.  How does an application put itself in the Dock? Is there a way to turn that off? Is it a setting?


Okay so I was viewing  question when I noticed that the suggested hot network questions is still suggesting this page.. but I am currently viewing it already.   I mean no offense to anyone, I have the utmost respect for the Stack exchange dev team and it isn't really a big deal and it harms no one I guess.. but maybe redesign hot network questions to show a different question instead?   It's just a little teeny tiny suggestion though.. and if it's like that by design then it's cool. Still love the site. Just trying to be helpful in the smallest way I guess

The hot questions algorithm . I like the effects, since I see lots of new interesting stuff every day rather than waiting 6-8 weeks varying amounts of time for the list to update.  However, the new algorithm also has the interesting side effect of recursing the same question:    Of course, this is a world-shattering workflow-breaking unicorn-hating waffle-despising ERROR tremendously minor matter. But, if the SE devs have opportunity during their amazingly large amounts of free time, it might be nice to add a check for the current page before populating the hot questions list.


I solved a similar question $a^4 = 2$ but I didn't find it hard. This one is taking a lot of my time and I still don't understand how to solve this. Here's what I have tried so far. edit: \begin{align} a^2 &= 3 \\ a &= \left(\frac mn\right) \\  a^2 &= \left(\frac mn\right)^2 = 3 \\ m^2 &= 3n^2 \\ m &= 3p \\ m^2 &= (3p)^2 \\ 9p^2 &= 3n^2 \end{align} In another similar question $a^3 = 2$, I had to divide a common number from each side to finally solve the problem. But with this problem, I don't know how to continue.

It is well known that $\sqrt{2}$ is irrational, and by modifying the proof (replacing 'even' with 'divisible by $3$'), one can prove that $\sqrt{3}$ is irrational, as well.  On the other hand, clearly $\sqrt{n^2} = n$ for any positive integer $n$.  It seems that any positive integer has a square root that is either an integer or irrational number.        How do we prove that if $a \in  \mathbb N$, then $\sqrt a$ is an integer or an irrational number?      I also notice that I can modify the proof that $\sqrt{2}$ is irrational to prove that $\sqrt[3]{2}, \sqrt[4]{2}, \cdots$ are all irrational.  This suggests we can extend the previous result to other radicals.        Can we extend 1? That is, can we show that for any $a, b \in \mathbb{N}$, $a^{1/b}$ is either an integer or irrational?


I have installed QGIS 2.0.1 on Ubuntu 14.1, yet I am not able to update to 2.8 or 2.10 since the proposed repository paths installations do not work. Anybody who can guide me through with a click instruction?

I am relatively new to Linux, so can you indicate the exact commands (step-by-step) that I need to type to get the latest QGIS installed on Ubuntu 14.04.  I have tried to follow the instructions provided here  but I haven't managed to install anything.  Can someone explain to me step by step process of doing it. Right from adding the QGIS repository on the sources list.  I have Ubuntu 14.04.1 LTS installed on a 32-bit Dell Latitude E4310 Machine


I don’t know any man that is present here.   I don’t know any man who is present here.      Which is correct? What is the difference in meaning between these two sentences?

How does one decide whether to use who or that? In the title example:   The correct pronoun is who. The correct pronoun is that. Either is correct. They're interchangeable. It depends on the context.


I've recently reached enough reputation on one of the sites to be able to cast delete votes. I am not sure when a question is supposed to be deleted as opposed to just remain closed.   What criteria should I use when deciding whether or not to cast my delete vote?

What circumstances can cause a question or answer to be deleted, and what does that actually mean?    How can a post be deleted? When can't I delete my own post? Can I still see my post even after it's deleted? Can I see a list of my deleted posts? How can I undelete one of my posts? What does deletion mean for a post? How do votes to delete work? What are the criteria for deletion? What else should I know about deleted posts? If I flag my question with a request to delete it, what will happen?       For more information, see the articles about  and  in the .


I downloaded Ubuntu 64-bit for Windows 8.1, and on that little .exe file where it said restart to test and see Ubuntu, I restarted and nothing happened. I'm confused.

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?


Working on a site and and working on some simple fixes for how it renders in IE (Using IE v11, everything seems to work fine on edge)   I have a <div> set to display:none and with a padding: 1% 3% 1% 3% and then set to display:block when the user hovers over it  The <div> is a little taller in IE than it should be. The problem seems to be caused by the extra padding so simple solution, simple, just remove the padding in IE.   I have a Javascript file going to fix it, where I have some other fixes as well (The code snippet worked for the classList.remove I have set, so I don't think the problem is my code, but I could be wrong?)  I have tried both element.style and tried element.style.setAttributeand neither set the style. Not sure why. Any help would be appreciated! Thanks!   JS below:  var feat1 = document.getElementById('feature-1'); var feat2 = document.getElementById('feature-2'); var feat3 = document.getElementById('feature-3'); var mainFeatHov = document.getElementById('main-feature-hover');    var isIE = !!navigator.userAgent.match(/Trident/g) || !!navigator.userAgent.match(/MSIE/g);  if(isIE){   feat1.classList.remove('col-md-4');   feat2.classList.remove('col-md-4');   feat3.classList.remove('col-md-4');   mainFeatHov.style.setAttribute('padding','0% 3% 0% 3%!important;'); };

Title pretty much sums it up.  The external style sheet has the following code:  td.EvenRow a {   display: none !important; }   I have tried using:  element.style.display = "inline";   and  element.style.display = "inline !important";   but neither works. Is it possible to override an !important style using javascript.  This is for a greasemonkey extension, if that makes a difference.


How to read a .class File located either in Local or Distributed File system to a Class object in Java?  I have a hello.class File in the local file system and in some cases it is in Distributed File System. I have a new application where I want to read the external hello.class file and construct a java.lang.Class object how do I do that?   Note: My hello.class is not in the class path of my Application and I still want to read just like I would read some external text file but I want to construct a java.lang.Class object?

Why is it so hard to do this in Java? If you want to have any kind of module system you need to be able to load JAR files dynamically. I'm told there's a way of doing it by writing your own ClassLoader, but that's a lot of work for something that should (in my mind at least) be as easy as calling a method with a JAR file as its argument.  Any suggestions for simple code that does this?


Let $\mathscr{M}$ be an $\mathscr{L}$-structure; we say that a definable $\mathit{X}\subseteq\mathit{M^n}$ is strongly minimal if $\mathit{X}$ is defined by an $\mathscr{L}_\mathit{M}$-formula $\phi(v)$ and for any $\mathscr{M} \prec \mathscr{N}$, if $\mathit{X}^\mathscr{M}$ is the subset of $\mathscr{N^n}$, then any definable subset of $\mathit{X}^\mathscr{N}$ is finite or cofinite.  Suppose $\mathit{X}\subseteq\mathit{M^n}$ is strongly minimal, and let $\mathit{acl^X} = \mathit{X} \cap \mathit{acl(A)}$ for $\mathit{A} \subseteq \mathit{M}$. Show that if $\mathit{x} \in \mathit{acl^X(A \cup \{b\})}$ and $\mathit{x} \notin \mathit{acl^X(A)}$ then $\mathit{b} \in \mathit{acl^X(A \cup \{x\})}$.  I've wrestled with this problem for a little while now and I'm honestly not quite sure what to even do here, at this point I'm really just looking for a nudge in the right direction--whether that be a little perspective or a question to make me think about this differently. This problem comes from David Marker's Model Theory: An Introduction page 106, problem 3.4.15 part (a).  Here is what little I've got so far: if $\mathit{x} \in acl^X(A \cup \{b\})$ then $\mathit{x}$ is algebraic over $\mathit{A \cup \{b\}}$, so there is some formula $\psi(v, \bar{w})$ and $\bar{a} \in \mathit{A \cup \{b\}}$ for which $\mathscr{M} \models \psi(x, \bar{a})$ and the set $\mathit{\{x_0 \in M:\mathscr{M} \models \psi(x_0, \bar{a})}\}$ is finite. Because of the definition of of $\mathit{acl^X}$, anything in it is also in $\mathit{X}$, which would allow me to make use of its strong minimality, though I'm unsure of where that comes in. Also, since $\mathit{x \notin acl^X(A)}$ doesn't that force the $\mathit{\bar{a}}$ parameter for $\psi$ to be precisely $\mathit{b}$ ?

I was reading David Marker’s Model Theory and came upon the following problem in Chapter 3.  Setting  Let $ \mathcal{M} $ be a saturated $ \mathcal{L} $-structure.   A definable subset $ X \subseteq M $ is said to be strongly minimal if and only if $ X $ is defined by an $ \mathcal{L}_M $-formula $ \phi(v) $ and every subset of $ X^{\mathcal{M}} $ definable in $ \mathcal{L}_{\mathcal{M}} $ is either finite or co-finite. $ {\text{acl}^{X}}(A) \stackrel{\text{df}}{=} X \cap \text{acl}(A) $ is the set of all $ b \in X $ such that $ b $ is algebraic over $ A $, i.e., there is an $ \mathcal{L}_{A} $-formula $ \psi $ such that $ \mathcal{M} \models \psi(b) $ and $ |\{ c \mid \mathcal{M} \models \psi(b) \}| < \infty $. $ A \subseteq X $ is called independent if and only if $ a \notin \text{acl}^{X}(A \setminus \{ a \}) $ for all $ a \in X $.   Problem  I would like to show that if $ b \in {\text{acl}^{X}}(A \cup \{ c \}) $ and $ b \notin {\text{acl}^{X}}(A) $, then $ c \in {\text{acl}^{X}}(A \cup \{ b \}) $, and that for any $ A \subseteq X $, there is an independent $ B \subseteq A $ so that $ A = {\text{acl}^{X}}(B) $.


My friend heard that tea is worse for drinking than water because "cells have a special membrane and tea has special supplements and membrane doesn't let tea pass and this is why skin is dry even when you hydrate with tea a lot", something about "lipid bilayer".  Is there is some nice scientific article on water andd tea difference to human organism?

Please forgive my ignorance on the topic and I hope this is a "on topic" question here. It was a toss up between this SE and Physical Fitness SE but I want a more scientific answer.    I came at a impasse in a conversation with another fitness enthusiast. They stated that if you are targeting your water intake during the day then drinks with a diuretic effect (tea/coffee) count negatively towards that water intake total.  So, is it true that one should over-compensate if drinking these diuretics? Or does the water content of drinks like coffee and tea balance out or even positively hydrate you?


I'm prototyping a two-player typing game in Unity. I don't have any experience making multiplayer games, so I'm not sure how to best approach the netcode.  For this game all I think I really need is an API for sending messages to and from a server - the two clients only care about what the other one is typing, and there isn't any gameplay that's even remotely related to physics. Looking into UNet, it seems like the parts based on synchronizing game objects do more than my game needs, but the  from the HLAPI seems like a good fit. That said, this is a real time game, so low latency is ultimately more important than any API style considerations.  The wrench, however, is that Unity is deprecating UNet without shipping any replacements. I'd start working with HLAPI, but I don't want to have to replace all of the networking code down the line or even have to shut down the game when Unity's servers go down, if that's what will happen after using HLAPI.  So as a beginner to multiplayer development, with relatively low API requirements, where do I go when Unity multiplayer is in flux? Should I learn the DOTS-Netcode mentioned in ? Should I go with a third party solution like Photon? Or will the HLAPI be sufficient, even post-deprecation?

If you look at this  you'll see UNet is deprecated and will be removed in the future.  I'm developing a mobile multiplayer game, i've red official advise about it but they say "You can publish it with 2018.4 (LTS)" and I can't use 2018.4 version because in my project i use LWRP which is not in the 2018.X versions.  I've found the alpha version of the new system right    My questions are:  1- Should i use the alpha version of the new system? And can i publish my game with it?  2- Should i wait for the new system came out? (I can't wait for months)  3- Should i try to use other third party systems like Photon?  Or is there any way to publish my game with nice multiplayer system?  Note: I can't pay for multiplayer matchmaking system. Because of that i want to make Hosting multiplayer game.


I am using the vim latex suite and when I type ... it automatically changes them into \ldots if it is text or \cdots if I am in a math environment. So I thought that \cdots is the "right" thing to use in math.  But I just now saw that using \cdots it looks very odd with something like this:  $b_{1}, b_{2}, \cdots, b_{n}$   In the document it looks simliar to this formatting: b1,b2,... ,bn After the dots and before the comma there is a whitespace. If I use \dots there is no space at all between them.  What would be the right way to do dots? Should I just stay with \cdots but which lookes a little bit strange? Should I use \cdots and add spaceing by myself where I need it?

I came to wonder, what is the difference between the following?  \dotsc \dotso   As well as between:  \dotsb \dotsi \dotsm


I tried all day long to get the value of the following infinite series..  $\displaystyle \sum_{k=1}^{\infty} \dfrac{2^{k}}{{2k+1}\choose {k}}$  which seems to be $\dfrac{\pi}{2}$ by my matlab iteration.   Can anyone help me to get this value?

How to find the sum of this series?  $$\sum_{k=0}^{\infty}\cfrac{{2}^{k}}{\binom{2k+1}{k}}$$  It seems very easy. But I still can not work it out, can anyone help?


I have 2 corrupted RAM module, on offset: 46xx MB and 13xxx MB (from memtest on boot) How to prevent Linux to access/alloc/read/write into those offset?  Here's the result of memtester on ~1000 MB to ~1400 MB:

MemTest86+ (the version included with Ubuntu 13.04) says  Failing address: 002f796c48 -    759.5 MB   What should I specify in the memmap kernel parameter to bypass this area?  I've tried running memtester 770MB and it says everything is ok so it doesn't look that the MemTest's indications means an error in the 759.5th MB from the start.  How to interpret this MemTest indication to configure memmap?  I have no money to buy new RAM now and the error seems to be single so I hope I can just override it.


We have State and Country Picklist enabled in the org. I cannot find a way to find out the list of states based on the selected country. I need this in the lightning component.   I've used DescribeFieldResult in Apex to get the country and return it to the component in init. It is fine. But I cannot find any way to filter the States based on CountryCode.   Is there any direct way to do this? Or should I be implementing via adding those into Custom Settings.   <aura:attribute name="dynamicCountry" type="Object[]"></aura:attribute> <aura:attribute name="dynamicState" type="Object[]"></aura:attribute>    <lightning:inputAddress         aura:id="myaddress"         addressLabel="Address"         streetLabel="Street"         cityLabel="City"         countryLabel="Country"         provinceLabel="Province/State"     postalCodeLabel="PostalCode"         street="1 Market St."         city="San Francisco"         country="US"         countryOptions="{! v.dynamicCountry }"         provinceOptions="{! v.dynamicState }"         postalCode="94105"         required="true"     />   I get the countryoptions and provinceoptions populated from apex in init of lightning component. Both of them would get populated. The issue is filtering out the state based on country code in apex (and it always returns me the full list). I still need to write a change event on the inputAddress field to fire when country is changed (and call the function to populate the state). But I need to figure it out at Apex level how to achieve this.   Note: I also need to make this work with multiple languages. Hence I'm choosing to get it from the Country State picklist values.

It's not too hard to present the Contact/Account  themselves, but the dependency filtering where when you select "United States" as the country only the 50 or so relevant states are presented seems hard to do.  I don't see anything helpful in the  component. The subject is not mentioned in the  documentation so I am assuming the dependency logic not addressed there - or is it?  I haven't found a paid or free component on the  for this.  Beyond that we seem to be back in the territory of each having to get hold of the data somehow - e.g. via a web service call to the  or in Apex through this somewhat hacky  but hard to leverage in Apex  technique - and then each writing our own client-side logic.  Is there a good ready made solution to this problem that I haven't found yet?  PS  Did some experimenting with  and with a bit of caching added the data for the default state and country picklists can be generated in about 100ms. So if no better solution comes along, I'll use that code - added below in an answer - at the server-side and write a bit of custom client-side code.


I am an Australian in Spain on a 8 month student visa. I'm wondering if I can apply for the 90 day tourist visa while I'm here. Another option may be to leave to a non-Schengen zone like UK and return to Spain to start the 90 day visa. Any tips would be greatly appreciated!

I have a 1-year residence permit from one Schengen country that is now expiring. Upon its expiration, I would like to get my 90/180 days validity as a tourist to stay, or return here as soon as possible.  I understand that the tourist short-stay scheme is based on the 90/180 days "counter". But what happens if my previous stay was not tourism but residence (as searching year). Wouldn't that mean that I can quickly exit and re-enter the Schengen area to activate my tourist stay?   Also, is there a way to change this purpose of stay without exiting the Schengen area?


I just started to work with threads and quickly I came to the very common question of how many threads are too many? After doing some research I got even further confused.  task  I have 16 cores and a application generating 1000 objects, being despite from construction parameters consistent. Creating 1000 threads would usually create a huge overhead destroying the performance advantage from multithreading according to msdn documentation and  . Also I must stay within the 3.5 NET 32 bit limit ().  Question 1 Having such a unilateral task, is it possible to create more threads than cores on the computer? Is .NET  optimizing something in there? What is the maximum number of threads I should use?  Question 2 Is there a simple beautiful solution, other then queueing it with limit resources? Something like a semaphore where I create all the 1000 threads but immediately inactivating the threads in order to not allocate the default thread stack?

What is the maximum number of threads you can create in a C# application?  And what happens when you reach this limit?  Is an exception of some kind thrown?


I spent a while working on the floor for a forest bump map but it wont work in BGE. Is there any way i can make the bump map work in BGE?

I have a sphere having a planet material MADE WITH NODES, and I want to convert this material into an image texture; because this material is made with nodes and only works in Blender, but I want to use in another software. This is my sphere material :   For Example : This is Jupiter :  And this is the texture :  In this case I used a downloaded image for Jupiter to be the material but I want the opposite, I want to change the material to image texture Like The shape of Jupiter texture. Is there anyway in Blender that can achieve my goal ? This is the file with my sphere material .  Textures Needed :  Albedo / Color / Diffuse Normal Map Roughness Glossines  I am using normal nodes and I am not useing the new Principled-shader


I believe I need to show that $\frac{q!}{x!(q-x)!} = aq $ where  $a\in \mathbb{Z}$ How can I show this?

Prove if $p$ is a prime then $p \mid \binom pk$ for $k\in\{1,\ldots,p-1\}$  I don't really know where to begin with this one.   I can see that I have to use the fact that $p$ is prime somewhere - the same is not true for composite numbers, for example $4\nmid 6=\binom42$.  I have checked that this is true for the first few primes:    $3$ divides $\binom 31=\binom32=3$ $5$ divides both $\binom 51=\binom 54=5$ and $\binom 52=\binom 53=10$ $7$ divides $\binom71=\binom76=7$, $\binom72=\binom75=21$ and $\binom73=\binom74=35$.


I am implementing (in C++) a method to detect when an overlap is occurring between two static, axis-aligned shapes on a 2d plane. The shapes are either squares or circles, and therefore there are three cases I need to consider for overlap: square-square, circle-circle, and circle-square.  Square-square and circle-circle were simple enough, but I am struggling to find any solid information online about what the correct algorithm is for calculating square-circle overlap.   I am aware that I could embed the square inside a circle (or vice versa) as a rough method, but I'm interested in what would be considered the cleanest way to do this more precisely?  Researching it online suggests there is a 'correct' answer to this question, but it isn't made clear what exactly that answer is.

How can I tell whether a circle and a rectangle intersect in 2D Euclidean space? (i.e. classic 2D geometry)


This is my data: {   "bookingFee": "0",     "inventoryId": "2001600236110005688",     "inventoryItems": [{         "operatorServiceCharge": "0.00",         "passenger": {             "age": "26",             "gender": "MALE",             "title": "Mr"         },         "seatName": "5",         "serviceTax": "19.00"     },     {         "operatorServiceCharge": "0.00",         "passenger": {             "age": "26",             "gender": "MALE",             "title": "Mr"         },         "seatName": "5",         "serviceTax": "19.00"     }],     "status": "BOOKED",     "tin": "123", }  As you see , "inventoryItems" can be just single object sometimes and some times multiple arrays like above ! Can it be saved in mysql column like "inventoryItems" or i need to create a new joint table to add these ? And each "inventoryItems" items has passenger with various data also - how to handle that ? Kindly suggest ? which is best practice ?

Why do database guys go on about normalisation?    What is it? How does it help?    Does it apply to anything outside of databases?


When you run the commandsudo apt-get install -y Vivaldi Vivaldi being an example, but what does the   `-y`    Argument achieve?

I always see commands like this  apt-get -y install    What is the -y tag for and what is the difference between apt-get install with and without the -y tag?


I have recently noticed a couple of problems when using the editor to re-edit an answer when using the Edge browser on Windows 10:   the editor is scrolled to the bottom of the text (as oppose to starting at the top), when you click the "Edit" link. I now see 3 blank lines are displayed for each blank line used for spacing in the original answer.   Using Edge the editor looks like this:    Using Firefox the editor looks like:    As you can see in the Edge browser the extra white space makes it hard to follow the flow of the answer. This is behaviour that I noticed only start to happen in the past week.  Does adding the "Bug" tag to this question mean someone from StackOverflow will look into it? Or is there some other place I should report this behaviour?

Lately, I've noticed that extra lines are being added when I create questions/answers. For example, if I write:   Your problem is X, Y, Z. Fix it by doing:      Code  Then maybe also do some other thing.  Oh, and some other thing as well.   When I post it, then go back into the editor, it's been changed to:   Your problem is X, Y, Z. Fix it by doing:       Code   Then maybe also do some other thing.   Oh, and some other thing as well.   Which is mildly annoying since that causes less to be displayed in the box at once, but whatever.  The weird thing is though, the added line isn't properly treated as a newline, even though it does appear to be caused by a newline. A lot of lines that look like they should be empty don't even get rendered. If I delete the original lines that I entered leaving only the "new" newlines, I get weird behavior:    I tried selecting the characters involved and inspecting them in Python, and they just appear to be newlines, so I have no idea what the problem is.    The only browser I've been able to reproduce it in is Edge (version 44.18362.329.0). It does not happen in Chrome. This has been happening for ~3 days now.    There is also a problem with link embedding and code formatting. If while editing I highlight some text and either try to embed a link (interlinked circle button) or format it as code ({} button), it often puts the wrong text between the […]s when embedding, or formats code that I didn't highlight (and doesn't format the code that I did highlight).


I am following a Coursera course called "Introduction to Mathematical Thinking" by Keith Devlin. There is a lecture in the course by the name of Implication. In that video, while deriving the truth table for =>, few things were unclear to me.  Let's just say a $\Rightarrow$ b. If speaking of genuine implication, studying mathematical thinking implies my math improves. So, we are assuming already that "Studying mathematical thinking" = True. And by definition, "My math improves" = True. However, I take the condition where "My math improves" = False, makes the whole statement false. So, we have (T,T)=T; (T,F)=F. Now, in the lecture, what they do is take a condition a $\nRightarrow$ b. In the next line, they state an obvious statement, where they tell that for this statement to be True, even though a = True, nevertheless b = False. The next line, however, is the one that concerns me. They conclude that apart from the case (T,F) = T for a $\nRightarrow$ b, all other cases are False. But my concern is that I understand this conclusion for (T,T) case. But how can you say that for (F,T) and (F,F) in the case of a $\nRightarrow$ b????? (In the next line they say that a $\nRightarrow$ b = ~(a $\Rightarrow$ b). I understand that bit.)

I am currently doing the Intro to Mathematical Thinking course on Coursera. A quiz therein, asks:  For what truth values of Φ and Ψ do we define Φ ⇏ Ψ to be T (true)?  It says the right answer is Φ is true and Ψ is false.  I understand that; but I do not follow why the reverse is not right. That is, why does Φ false and Ψ true does not make the statement Φ ⇏ Ψ to be true.  I am confused because if Ψ is true while Φ is false, the truth of Ψ does not follow from the truth of Φ and so it should be that Φ ⇏ Ψ. Could someone please explain?


Prove that there exists a monotone nondecreasing function $f:[0,1] \rightarrow \mathbb{R}$ discontinuous in rationals of $[0,1]$   I tried to test functions of the type  $$ f(x)=\begin{cases} \frac{1}{q} & \text{if } x=\frac{p}{q} \mid p,q \in \mathbb{Z}^+ \,\,\, \text{and} \,\,\, \gcd(p,q)=1  \\ x & \text{if } x \not\in \mathbb{Q} \end{cases}$$ which is discontinuous in all rationals, but is not monotone.

I have really no idea about this:  Problem: Show that there exists a function $f:[0,1]\rightarrow\mathbb{R}$ such that:  $f$ is discontinuous in all $x\in \mathbb Q$. $f$ is increasing in $[0,1]$. $f$ is integrable.   EDIT: Sorry, it is not discontinuous in all $x\in \mathbb R \setminus \mathbb Q$, just in $\mathbb Q$.


The width of the backdrop is 20 ft. It will be projected onto a wall. What size should the photoshop dimensions and the resolution be? This is not going to be a print file, it is going to be displayed digitally!

I think my title question says it all. I have hand drawn some designs (A3) that will be projected onto a 9m X 7m brick wall. This design will be painted as a mural.  I'm concerned about the appropriate file size and format to use as I need to retain a clear image to work with.


I'm pretty geeky, but I haven't really followed all the tech behind LTE rollouts and wireless bands and whatnot. I barely know the difference between CDMA and GSM. I know Verizon didn't use a SIM and generally phones weren't interchangeable, but that now they do use SIMs... Overall, I'm confused. But, confused or not, I want to buy a new Nexus phone. The  for the 6P just lists a bunch of bands and says:  GSM/EDGE: 850/900/1800/1900MHz UMTS/WCDMA: B1/2/4/5/8 CDMA: BC0/1/10 LTE (FDD): B2/3/4/5/7/12/13/17/25/26/29/30 LTE (TDD): B41 CA DL: B2-B2, B2-B4, B2-B5, B2-B12, B2-B13, B2-B17, B2-B29, B4-B4, B4-B5, B4-B13, B4-B17, B4-B29, B41-B41 Phone is carrier-unlocked with wide-range band support for service providers worldwide. Check with your service provider for more information.  That last bit is not very promising, since such information is generally buried in knowledgebases and forums on carrier websites, and anyway the carriers mostly want to sell me a phone directly and aren't highly incentivized to make this simple. Does this big long list mean that everything in the US — or, at least, T-Mobile, Sprint, AT&T, and Verizon — will work? Will they all work everywhere that they have coverage, or might it depend on certain bands being deployed in some areas? To make things worse, the 5X has a slightly different list — under LTE (FDD), 30 is gone but 1 is added. CA DL becomes LTE CA DL, and includes B4-B7 and B4-B12. Does this make any practical difference?

Sometimes it's desirable to use a device on a carrier that does not officially sell it. Often this is due to regional differences and travel (for example, using a US phone in Europe) but also because some carriers simply do not offer phones that other carriers do.  How can I determine if it's possible to use my phone on a different carrier, and which carriers it is compatible with?    This community wiki is intended to be a canonical answer to a common question. If you feel that improvements could be made then please edit the post(s).


I'm having a little bit of confusion with the following. The integral is given as:  $$\int_0^1 x^{-1/2} dx = [2x^{1/2}]_0^1 = 2$$  But from what I understand, a Riemann integrable function must be bounded. How does one reconcile this with the fact that   $$x^{-1/2} \to \infty \text{ as }x \to 0$$   I suppose a natural follow up question would be: If the integral of a function is finite, is it Riemann integrable?

Most statements regarding Riemann integrals (at least the ones that I have encountered) begin with the statement "for $f(x)$ bounded on $[a,b]$." I am wondering if Riemann integrability implies boundedness. I think that this has to be the case, but I am not sure. If Riemann integrability does imply boundedness, are improper integrals considered Riemann integrals? I would think that improper integrals wouldn't be Riemann integrals since improper integrals are allowed to be equal to $+\infty$ or $-\infty$. Or are improper integrals that are not equal to $\infty$ considered Riemann integrals?   I am confused.


I two singleton classes that shares exactly the implementation except that differ on types of objects. Because i know in the future i will keep adding more singleton types with same implementation i thought it would be a good idea to refactor the singleton class into generic base class. However i have errors on like shown in the snippets below and i don't know how to implement a singleton into a base generic class. public class BaseClass<T> where T: new() {    //Singleton instance     protected static readonly Lazy<T> _instance = new Lazy<T>(() => new T (param)); //Error on new T    protected static SqlTableDependency<TableC> tableDependency;     //Constructor    private T(IHubConnectionContext<dynamic> clients)    {        Clients = clients;          _tableDependency = new SqlTableDependency<TableC>(             ConfigurationManager.ConnectionStrings["DBConnectionString"].ConnectionString, "TableC");    }    //Properties    public static T Instance    {         get         {             return _instance.Value;         }     }      private IHubConnectionContext<dynamic> Clients     {         get;         set;     } }

I have the following C# singleton pattern, is there any way of improving it?       public class Singleton<T> where T : class, new()     {          private static object _syncobj = new object();         private static volatile T _instance = null;         public static T Instance         {             get             {                 if (_instance == null)                 {                     lock (_syncobj)                     {                         if (_instance == null)                         {                             _instance = new T();                         }                     }                 }                 return _instance;             }         }          public Singleton()         { }      }   Preferred usage example:   class Foo : Singleton<Foo>  { }    Related:


When I am in the main screen where I get to choose which account, it does not give me the option to remove an account. When I click the arrow, it just signs into that account.

I have three accounts among the multiple accounts I have for Google's products. One of them belongs to a friend who accidentally made his account one of mine when he was using my PC.  How do I remove his account from my Google multiple accounts? Logging out from his account doesn't work. His account still displays under the user dropdown even though I can't log in to it.


I connect to computer B this way.  ssh -X computerB@10.2.1.123   Now when I launch firefox it launches on computerB  firefox   How do i make it launch in computer A? Because I dont have access to the screen of computer B.

When I SSH to a remote box  $ ssh -X remotebox   then start firefox on the remote box  remotebox$ firefox   and I have firefox running on my local machine, a local firefox window will open. no firefox process is running on the remote box.  If firefox is not running on my local machine then a remote firefox window will open.  Why is it opening a local firefox window? How can i prevent that?    Here some more information of my local system.  Linux lesmana-laptop 2.6.32-24-generic #42-Ubuntu SMP Fri Aug 20 14:24:04 UTC 2010 i686 GNU/Linux  No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 10.04.1 LTS Release:    10.04 Codename:   lucid  DISPLAY=:0.0  Mozilla Firefox 3.6.8, Copyright (c) 1998 - 2010 mozilla.org   Information of remotebox.  Linux dxray 2.6.22.19-0.4-default #1 SMP 2009-08-14 02:09:16 +0200 x86_64 x86_64 x86_64 GNU/Linux  LSB Version:    core-2.0-noarch:core-3.0-noarch:core-2.0-x86_64:core-3.0-x86_64:desktop-3.1-amd64:desktop-3.1-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.1-amd64:graphics-3.1-noarch Distributor ID: SUSE LINUX Description:    openSUSE 10.3 (X86-64) Release:    10.3 Codename:   n/a  DISPLAY=localhost:15.0  Mozilla Firefox 3.0.14, Copyright (c) 1998 - 2009 mozilla.org   The following command starts a remote firefox session with a remote firefox window.  remotebox$ firefox -no-remote   The following command produces a brief delay, then drops back to prompt and a local firefox window pops up. No firefox process running on the remotebox.  remotebox$ firefox     Information of remotebox2.  Linux marvin 2.6.31-22-generic #60-Ubuntu SMP Thu May 27 00:22:23 UTC 2010 i686 GNU/Linux  No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 9.10 Release:    9.10 Codename:   karmic  DISPLAY=localhost:11.0  Mozilla Firefox 3.6.8, Copyright (c) 1998 - 2010 mozilla.org   The following command on remotebox2 starts a remote firefox session as expected.  remotebox2$ firefox   I do not know why firefox on remotebox2 starts a remote session instead of a local session.


Just bought it on ebay from a chinese seller with high rating. The item description said it was GENIUNE. But I'm still skeptical. Even thought It works well on my pc the box looks suspicious on the backside. What should I look for to verify the authenticity of this controller?  Please take a look at these photos, and use them as an example if possible.

I recently bought a Wired Xbox 360 controller from Ebay, and I'm trying to figure out whether it's counterfeit.  It's two-tone black and gray, which  means it's probably the Elite edition of the controller.  Here's what makes me suspicous:   There's no breakaway cable near the USB port (Microsoft's term is ), the cable is one piece from controller to USB port The cord is about 7 feet long The hologram sticker on the back says "Microsoft" but doesn't have the real Microsoft logo, there's no slice taken out of the "o" in "Micro"   Here's a number of details that are correct, as far as I can tell:   The "Microsoft" logo etched on the top of the controller is correct, it has the split "o" and connected "ft" It seems to work correctly when plugged into my computer The front of the controller matches  exactly At the USB end of the cord, the grey wider plastic piece you're intended to pull on has the little nub on top. (You can see what I'm talking about in , the nub is to the left of and below the first "w" in the watermark)   I know pictures would probably be helpful, I'll work on taking some.


I was paid a few hundred dollars to review a few textbooks. I submitted an invoice in Dec 2016, and received payment in Jan 2017. When I pay taxes on this income, does that count towards 2016 or 2017?  The context of my question is US federal taxes.

Suppose I did some contracting in December, my client puts a check in the mail in December, and I receive it and cash it in January.    Does my income count for December or January?


I'm trying to take a list in python and append (in a tuple) a few variables and also in the tuple add every item from another list, so that each individual item in the list has it's own place in the tuple.  Basically adding more elements to a tuple, from another list.  I tried running a for loop inside the tuple but of course that didn't work. I've seen someone do something similar but not sure how it actually works.  items = [] listy = [] var1, var2, var3 = 0, 1, 2 items.append((var1, var2, var3, for l in listy))   I just get an invalid syntax error. Again, this is just a visualization of what I want to happen. Here is another example of how I see it looking:  list[var1, var2, var3, listy[0], listy[1], listy[n]]   Thanks for your input. Sorry if this is a stupid question, I haven't been using python too long but couldn't find anything specific online.

What's the difference between the list methods append() and extend()?


Prove that there are no $x$ and $y$ such that $(x/y)^2 = 2$  It says that I can assume that $x$ and $y$ are relatively prime so I started the proof as:   $x$ and $y$ relatively prime $\implies$ there are integer $m$ and $n$ s.t $mx + ny = 1$ $\implies (m/n)^2 = ((1-ny)/(xn))^2$   I don't know what to do after this. Thanks

I used the method of contradiction by assuming that $\sqrt 2$ is a rational number. Then, by the definition of rational number, there exist two integers $p$ and $q$ whose ratio equals $\sqrt 2$. Thus, $$\frac pq = \sqrt2\tag{x}$$  Squaring both sides, $$p^2/q^2 = 2\tag{a}$$  or $$p^2 = 2q^2\tag{b}$$ This means that $p^2$ is an even number, implying that $p$ is even.  Now, any even integer can be written as $2^kf$ where $f$ is any odd integer and $k$ is some positive integer (the minimum value of $k$ and $f$ is $1$ since even numbers start from $2 = 2^1\cdot1$). For odd numbers, $k=0$.  For example, $8 = 2^3 \cdot 1$, $4= 2^2 \cdot 1$, $18= 2^1 \cdot 9$, $24 = 2^3 \cdot 3$, $-12= 2^2 \cdot(-3)$, etc.  Now, from $(b)$, $q^2$ can be even or odd.  Case 1: $q^2$ is even (thus meaning $q$ is even). Then $p= 2^{k_1} \cdot f_1$ (say) and $q = 2^{k_2} * f_2$ (say). Note here in this case, both conditions $k_1=k_2$ and $f_1=f_2$ can't hold simultaneously since that would mean $p/q =1$ and here $p/q =\sqrt2$ (from $(x)$)). Let's consider the condition when $k_1=k_2=k$ but $f_1\ne f_2$. Then $$\frac{p^2}{q^2}=\frac{(2^kf_1)^2}{(2^kf_2)^2} = \frac{f_1^2}{f_2^2} =2$$ (from $(a)$), i.e.: odd/odd ($f_1$ and $f_2$ are odd) can never equal $2$.  Now lets consider $f_1=f_2=f$ but $k_1\ne k_2$, thus $(2^{k_1}f)^2/(2^{k_2}f)^2= 2^{2(k_1-k_2)}= 2$ meaning $k_1 - k_2 = 0.5$ but $k_1,k_2$ are integers, so their difference can't be $0.5$. (Also here, $k_1-k_2$ must be greater or equal to $1$ since $2^{k_1-k_2}=\sqrt 2$, $k_1-k_2$ can't be negative since $\sqrt 2>1$, but $k_1-k_2\ge1$ can't satisfy $(a)$ since the minimum value of $p/q$ in this case will be $2$ which is surely greater than $\sqrt2$.)  Now lets consider $f_1\ne f_2$ and $k_1\ne k_2$, thus $\frac{(2^{k_1} f_1)^2}{(2^{k_2} f_2)^2}= 2^{2(k_1-k_2)}\frac{f_1^2}{f_2^2}$ can never equal $2$ since $\frac{f_1^2}{f_2^2}$ is either odd or "odd/odd" ie: it doesn't contain 2 as a factor and $2^{2(k_1-k_2)}$ is a power of $2$. So in $2^{2(k_1-k_2)}\frac{f_1^2}{f_2^2}$, there's no chance of cancellation of the odd factor $\frac{f_1^2}{f_2^2}$.  Case 2: $q^2$ is odd (thus meaning $q$ is odd). $q=f'$ (say, here $k=0$ for $q$ but not for $p$), thus from $(a)$ $2^{2k}\frac{f^2}{f'^2} = 2$ but this isn't possible since a power of $2$ multiplied with odd factor can't equal $2$.  Thus, both case 1 and 2 suggest that for any possible combination of $k_1,k_2,f_1$ and $f_2$, $p/q\ne\sqrt2$, i.e.: for no value of integers $p$ and $q$, $p/q = \sqrt2$. Thus, this contradicts our assumption that $\sqrt2$ is rational. Therefore it must be irrational.  PLS NOTE that i would like to clarify that $f_1^2$/$f_2^2$ is either an odd integer or a fraction of odd/odd or 1/odd form, thus not containing  2 as a factor,for any $2^n$, if it has to be reduced to 2 , must be multiplied with $1/ 2^(n-1)$ but $f_1^2$/$f_2^2$ can't be of $1/2^[n-1]$ form since for odd nos, in $2^k$*f notation, k is 0 , so 2 vanishes as $2^k$ becomes 1 in this case thus f1/f2 can't be represented as  1/ $2^(n-1)$ in which n has to be existent.  therefore $2^{2(k_1-k_2)}\frac{f_1^2}{f_2^2}$ can never equal 2 as to further explain the 3rd condition of case 1  Difficulty: is my approach correct? This proof which I thought is different from proofs found on the internet or books since I have used $p$ and $q$ as any integers, which may have a common factor. So I am not sure if I am on right track. Will someone please check this out and make kind comments?


I am trying to eradicate my HTML code of tags such as <strong>, <i>, <b>, and <em>. I understand that <strong> and <b> can be accomplished in CSS by using font-weight: bold. I also understand that <italic> can be accomplished in CSS by using font-weight: italic. However, I am not sure how what the CSS equivalent for <em> is. After a lot of research, I really do not even see the difference between <strong>, <b>, and <em>.  Therefore, what is the difference between <strong>, <b>, and <em>, and what is the CSS equivalent of <em>? Any suggestions are appreciated. Thank you.

What's the difference between <b> and <strong>, <i> and <em> in HTML/XHTML? When should you use each?


I am starting an e-commerce website for local customers and the .com I want for the website has been taken (however the .in is available).  I want to know whether it is going to affect my SEO rankings or not if I use .in.  I want to expand the website for other countries too in the future.

Because I'm still living like it's 2008, I run a website with a .in TLD. The website has nothing to do we India and does not target Indian users.  Unfortunately, when I go to Google Webmaster Tools I see that Google have locked my geotargeting status to India:    On the , Google state that:     Sites with country-coded top-level domains (such as .ie) are already associated with a geographic region, in this case Ireland. In this case, you won't be able to specify a geographic location.   This seems implausibly inflexible, so I want to know if there are any sneaky ways of removing auto-geotargeting, or changing it to a more appropriate region?


Hagrid: If that dolt of a cousin of yours, Dudley, gets up to any mischief, you could always threaten him with a nice pair of ears, to go with that tail.  Harry: But, Hagrid, we're not allowed to do magic outside Hogwarts.  Hagrid: I know that, but your cousin don't, do he?

I'd like to know how the sentence "That don't impress me much" sounds to a native English speaker.  The phrase is the title of a song by Shania Twain, and to my eyes it contains a clear error. It is obviously intended, and I want to know what was the effect that the author wanted to obtain.  Other examples that come to mind:   “She's got a ticket to ride, but she don't care” — The Beatles “My love don't cost a thing” — Jennifer Lopez “It don't matter” — Akon “She don't care about me” — heard in the Lost series “It Don't Mean a Thing” — a jazz album title “The Sun Don't Lie” — another album title


Perhaps the circumstances are too specific for this to be a problem but I just noticed that you can tell how the last person to modify a post* voted if:   They did not ask, answer, or edit the question or answers AND   They are the first person to vote OR All votes are the same    Granted, you have to either have the privilege to see vote counts or be the person whose post was voted on to be sure of one of the last two but is this something that should be visible at all? Should a user who has just be down voted be able to look up their post in a list sorted by activity and get the user name who did it?  *To be clear, I'm not talking about just your own posts, though that would likely cause the most trouble. I noticed it here:   At the time I posted this question, it was modified by a user who had not edited the question or the answers, left an answer, or even left a comment. This means, unless there's another way to modify a post, that they voted on it. Since all of the votes on the question were up votes, it means they voted it up.  In this instance it was positive but should I be able to figure that out at all?

.       The  has no sign of the user sharth The  also does not have any sign of related activity   I would like to know why the user's name is associated with the question. At least why their display name shows up as having modified the question timeline activity.  Possible reason that I can think of is that, .  Is this the reason?  Is there a way (for normal users), to look for such details, other than looking at the user activity and the question's revision history.


Background:  I was using webpack (A javascript application) and missed a / in the config next to the directory.  So it created a directory called "client.."   I've tried everything I can think of to delete the file, and nothing has worked.  I even tried to remove it pragmatically via Java.  Does anyone know a way I can delete this file?   Not that based on the screenshot you will notice that normal methods of deleting hard to remove files did not work.  So this is somehow different than similar questions.  It was answered with using rimraf I was able to delete the file.

I have a folder on my desktop which is named ".." (which itself contains subfolders with an empty name). The folder can't be deleted the usual ways, even not when using the CLI. Does anyone know how I can remove this folder on Windows Vista 64-bit?  Renaming does not work, either (obviously).  This is what "dir /x" echoes:  09.10.2009  15:04    <DIR>                       . 09.10.2009  15:04    <DIR>                       .. 08.03.2007  11:18    <DIR>                       cgi-bin                0 Datei(en),              0 Bytes                3 Verzeichnis(se), 45.866.037.248 Bytes frei


I want to know how an emission light works. I have a small room, A window and a sphere as light. I want the light from inside to pass through the transparent glass window and the light from the outside to also pass through the same window. I have set the strength to 100 yet the light is not passing out of the room.  If I were to make another object other than a glass window (Like a wall lantern for example), are the settings for the material the same or do I have to change them? If they are different how do I set the settings for both?  blender file   getting error

Here's a sample scene:  A room with a window, a point light to project light into the room, an HDR environment outside the room and a nice Image by Rembrandt that should be somewhat reflected on the glass:    Using a standard glass shader on the window, the direct light from the lamp does not shine into the room, regardless of how bright that light is. So I can't recreate the impression of hard day light, with clearly defined areas of light and shadow.    Adding a transparent shader to the glass shader I get a very pleasing result. The light from the lamp illuminates into the room creating defined shadows, transparency seems unaffected, to see the HDR in the background, the refection seem correct to me (I also like how I get double reflections from the thick glass).    Even though I am quite happy with this solution, I've gotten a few comments on making a setup with light path nodes controlling the mix of transparent and glass. The biggest issue is that the reflections on the glass are brighter than what they should be.  So the question is: By using this approach am I messing up any of the qualities of glass? And if so, what would make a proper glass shader that is realistic, in terms of letting direct light through, while keeping reflections, refraction and transparency?  A file to play with:    The HDR image used was created by


I need to prove if this is true or false.If true then I need to Prove and if false I need to provide an example that disproves the statement.I tried many times but it didnt work.  Note:- Im new so I dont know how to write in the math format so if you know how to  please tell me

Assume  $$\lim_{n\to \infty}  (y_{2n} - y_n)=0$$  then  $$\lim_{n\to \infty} y_n$$  exists.  I know it's not true, and I can see a sequence that disprove that $(1,1,2,1,3,2,4,1,5,3,...)$ but I want a sequence that has formula.  hint/help?  thanks


When adding a bug report via Android app, list of specification items added to message body automatically. And for the last one (OS) extra space character is added (you can also see it in current post).   App Version: 1.0.85 Device Manufacturer: LGE Device Model: LG-D802   OS Version: 5.0.2 (152331922a212)

In the Stack Exchange Android app ➡ About ➡ Submit a bug report, when trying to report a bug, by default the configuration details are showing in the body section.      The content in the screenshot is as below (for reference of future search):    - App Version: 1.0.85 - Device Manufacturer: Motorola - Device Model: XT1033  - OS Version: 5.1 (2)   The four items are to be shown in the same bulleted list order, but there is one extra space before the - OS Version:, so it is causing the first three items to be in the same bulleted list order and the last one in the sub bulleted list.   The rendered output is below:   App Version: 1.0.85 Device Manufacturer: Motorola Device Model: XT1033   OS Version: 5.1 (2)    The issue is in the recent questions with the  +  .


This one I read "only" about 10-15 years ago, and I think it was rather recently written at that time.  It begins with a weird, probably alien structure being spotted in the solar system, already on its way out. (And no, it is not “Rendezvous with Rama” nor any of its sequels). Some ship, the captain of which is a woman, seems the one with the best chance to catch up with it before it is out of reach. Which they do, but they are trapped in some accelerator that sends them away at near light-speed velocity. The captain has just time to send back a message with some information about what she found there.  The middle is quite fuzzy. I cannot remember any details.  The only other thing that I remember is almost at the end. Somehow the captain receives a telepathic message sent from Earth (that must have been travelling at light velocity to catch up, considering how fast she is receding away) telling her she is considered (or rather, was considered eons ago, when the message was sent) as a hero on Earth, because the information she sent back was instrumental in hugely improving scientific knowledge. I am not sure how much confort that was for her.

I'm looking for a novel I read, probably in the mid 1990s.  The story involved an alien vessel/asteroid coming through our solar system and a human ship going out to meet it and then being stuck on it as it continues out into deep space.  As they explored the alien vessel they encounter other alien races who are also stuck, some of them go round looking for new arrivals to steal all their technology.  When they first land they find spires sticking out of the surface that are rotating with near infinite torque so they use this to generate power.


I had build new CPU with Keep Motherboard Same GIGABYTE GA-A320M-S2H AMD A320 AM4 MAX-32GB DDR4 Micro ATX PCIE16 Processor Replacement: AMD Ryzen 3 2200G with Radeon Vega 8 Graphics Desktop Processor 4 Cores up to 3.7GHz 6MB Cache AM4 Socket (YD2200C5FBBOX) Now I had bought "AMD Ryzen 7 2700" Octa Core new processor, like to replace Problem Domain Do I need to reinstall ubuntu operating system in case I change processor only ? Note: Correct in case I explain wrong way.

I recently upgraded my CPU from an Athlon II X2 250 to the Athlon II X4 610E(45W 4 cores -- can't beat the efficiency).  Is an ubuntu reinstall required?


Just once switched to OpenGL rendering, but after that changing to Blender Render or Cycles really doesn't help. Even after quitting Blender and then re-starting it and reopening the scene, it's still rendering with OpenGL.  What could possibly go wrong?   Here's my file

Blender is rendering an older version of my project, not the most recent one. I have made it using the Blender Render but it does not want to render in cycles either. A black and grey screen is rendered as if everything is transparent. Checked general camera, lighting and compute devises in case I messed something up but I can't find anything. All my textures and objects look normal, does anybody know what is wrong or what to check?  Ok added link:


I've been looking for a way to dial down reddit's white background late at night. I ended up using Control Freak (which is very cool) with my own custom styles. .   Except when it loads a new page it still  for a couple seconds before loading my custom styles (which show up in "user agent stylesheet" in dev tools)  Is there any way to prevent the screen from flashing bright white, like it does, before the user agent stylesheet is loaded?

When a page doesn't load immediately, Chromium and every other browser I tried display a white  screen before they get a response from it:    Even though chrome://settings/personal says it's using the GTK+ theme - in my case it's Darklooks, which has a dark background:    Is there a way to avoid this in Chromium? Or, if there isn't, is there a browser that does not have this "issue"?


Do I need a transit visa through Heathrow to the USA? I hold a Kenyan passport and will be in the USA for four weeks. My transit time at Heathrow is about 2 hours.

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


I have a disk that is 100% used, 400 GB of 400 GB, however I have moved more than 44 GB of files from it, but no extra space got available, the usage is still 400GB of 400GB.  Filesystem                        Size  Used Avail Use% Mounted on /dev/mapper/system-root            49G  5.1G   41G  12% / udev                               32G  192K   32G   1% /dev tmpfs                              32G  148K   32G   1% /dev/shm /dev/sda3                         158M   37M  114M  25% /boot /dev/mapper/vg00-lv_hana_backups  500G  471G   30G  95% /backup /dev/mapper/vg00-lv_B1H           200G   78G  123G  39% /hana/SAPBusinessOne /dev/mapper/vg00-lv_hana_data     400G   19G  382G   5% /hana/data /dev/mapper/vg00-lv_hana_log      400G  400G  280K 100% /hana/log /dev/mapper/vg00-lv_hana_shared   200G   35G  166G  18% /hana/shared /dev/mapper/vg00-lv_usr_sap       200G   45G  156G  23% /usr/sap //10.1.1.201/HANABackups          1.9T  698G  1.2T  38%  /windbackup/HANABackup comapny-sap:/hana/log # du -h 1.3G    ./mnt00001/hdb00001 794M    ./mnt00001/hdb00003 286G    ./mnt00001/hdb00004 288G    ./mnt00001 288G    .   As it can be seen from lsof, there are no files still being held open by processes>  lsof -n | grep '(deleted)' nautilus    6184       root   31r      REG              253,0       752    1753275 /root/.local/share/gvfs-metadata/home (deleted) nautilus    6184       root   32r      REG              253,0     32768    1753307 /root/.local/share/gvfs-metadata/home-bc638f00.log (deleted) shutdown  111517       root    0u      CHR              136,0       0t0          3 /dev/pts/0 (deleted) shutdown  111517       root    1u      CHR              136,0       0t0          3 /dev/pts/0 (deleted) shutdown  111517       root    2u      CHR              136,0       0t0          3 /dev/pts/0 (deleted)   I have also tried copying 44 GB of files of that partition and than I could not copy any of the files from that 44 GB back, not even one 1 GB file?

I have a Linux CentOS server, the OS+packages used around 5GB. Then, I transferred 97GB data from a Windows server to two folders on this Linux server, after calculated the disk usage, I see the total size of the two folders is larger than the disk used size.  Run du -sh on each folder, one use 50GB, the other one use 47GB  But run df -h, the used space is 96GB. (50GB + 47GB + 5GB) > 96GB  Is there any problem? Those two folders contain lots of files (1 million+). Thanks.


So, I'm drawing graphs using TikZ and pgfplots for my lecture notes. My question is about the two coordinate systems that are used in the following code: \documentclass{article}  \usepackage{tikz} \usepackage{pgfplots} \begin{document}  \begin{tikzpicture} \begin{axis}[axis lines = center, xlabel = $x$, ylabel =$y$, ymax=3, ymin=-1, xmax=5, xmin=-1 ,samples=500, ytick={1,2}, xtick={1,2,3,4}] % Code for the graph. \addplot[blue, domain=2.05:4.5, thick] {-x + 4}; \addplot[blue, domain=-0.5:1.95, thick] {x}; \draw[blue] (300,297) circle[radius=1.5pt]; \node[above right] at (300,297) {\footnotesize $y=f(x)$}; \end{axis} \end{tikzpicture}  \end{document}  Question: Why is it that the lines of the graph can be drawn with the coordinates of the axes, but the coordinates of the nodes have to be specified using some other system? Question: What is the other system? Is it easy to say where (0,0) in the "node system" is with respect to (0,0) on the axes? Ideally I would like to be able to use the axes coordinates for all aspects of the diagram. But, any help at all would be great! Thanks in advance.

I would like to know if there is a way to specify axis cs to be the default coordinate system inside a plot in PGFPlots, so I don't have to type axis cs: in front of every coordinate pair. Here's a MWE that shows what I mean (the actual plot is irrelevant).  \documentclass{article}  \usepackage{pgfplots}  \begin{document}  \begin{tikzpicture}  \begin{axis}[               xmin=0,               xmax=80,               ymin=0,               ymax=80,               grid=major,              ]   \fill [green, opacity=0.5] (axis cs:14,14) -- (axis cs:80,47) -- (axis cs:80,80) -- (axis cs:47,80) -- cycle;   \fill [red, opacity=0.5] (0,0) -- (axis cs:80,0) -- (axis cs:80,47) -- (axis cs:14,14) -- (axis cs:47,80) -- (axis cs:0,80) -- cycle;   \draw [thick] (axis cs:47,80) -- (axis cs:14,14) -- (axis cs:80,47);  \end{axis} \end{tikzpicture}  \end{document}


I'm still very new to Python and confused by the question below. below is the code: x = "p" y = x[:-2]  Why doesn't Python handle x[:-2] as an "out-of-bound" slicing and return "p"? In stead, it returns an empty string. Thank you!

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I like to know when noun is used as adjective.

While reading an article I came across the following sentence:  The more successful group, in terms of their creativity quality of their solutions...   Is this grammatically correct? Can a noun be used to describe another noun?


Right, I've searched the internet for days. I've tried getting new drivers and there is no button or gesture that manually disables my touchpad. If I go to my touchpad driver the "Disable" box is greyed out. I know that the i8042prt.sys controls both the touchpad and the keyboard, so if you can't give me any other method, can you tell me which files in i8042prt.sys control the touchpad so I can manually delete them? I don't care if the change is absolutely permanent as I have no use for my touchpad and if I ever need a mouse and don't have one I have a touchscreen.

What is the easiest way to disable the touch pad on a laptop?  I have a laptop which lacks a means to turn off the touchpad with a simple Function key sequence.  I would like to disable the touchpad so that it stops detecting movement when I am typing.  This is quite an annoyance as it sometimes results in deletions of sections of a sentence I am typing.  Right now I have a thick piece of paper over the top to decrease the sensitivity.  Any other suggestions on how to do this?


Consider this randomly chosen question opened in chrome, and later in the android app.        In Chrome, I can press and hold on any link to see the actual address before I even visit it. Whereas in the stack exchange android app, I'm not able to do so.        This is not an important issue, but I'd simply love to have such a preview feature on our app.

I think it would be good to have a way for the user to view the target URL of a link before following it. I'm pretty sure that I'm not the only one who dislikes blind-clicking -tapping links.   When I use SE in the mobile browser, I routinely long-press links to find out where they go before following them. I wish I could do the same thing in the app, with the same or a similar method.  (It's important that this won't conflict with text selection, since you can't long-press on links to select them now anyway.)


$$\lim_{x \to 0} \frac{x}{p} \left\lfloor \frac{q}{x} \right\rfloor =\;\;\; ?$$   My attempt:  $\frac{q}{x}-1 < \lfloor \frac{q}{x} \rfloor \le \frac {q}{x} $    . Then I consider four cases. In case 1 I took x and p both positive and then I multiplied above by $\frac{x}{p} $ and took limit and applied squeeze theorem. In other cases I did the same. My answer is $ \frac{q}{p} $.    Is the solution correct?

find the limit of:      $\displaystyle\lim_{x\to 0} \frac{x}{a}\cdot  \lfloor{\frac{b}{x}\rfloor}$      $ a,b>0$   i know that: $\lfloor\frac{b}{x}\rfloor\le \frac{b}{x} + 1$; and  $\lfloor\frac{b}{x}\rfloor\ge \frac{b}{x} -1$  but i cant seem to combine those using the squeezing theorem (i belive the limit is $\frac{b}{a}$)


Is there a way to express the following code through Python list comprehension?  newlist = [] for i,j in enumerate(old_list): if i==0:     newlist.append(j*2+1) else:     newlist.append(j*2)

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


I found some code through googling that allows me to export a data table to excel file. i successfully export the file from database table and save it in my document  My coding is:    using System;   using System.Data.OleDb;   using System.Windows.Forms;   using MySql.Data.MySqlClient;   using System.Data;  namespace ImportFile  { public partial class Form1 : Form {     public Form1()     {         InitializeComponent();     }     String connection = "SERVER=******;"DATABASE=dbd;"UID=root;"PASSWORD=pws;"Convert Zero Datetime = True";  private void BExport_Click(object sender, EventArgs e)     {         DateTime dat = DateTime.Now;         int time = dat.Hour;         int time1 = dat.Minute;         int time2 = dat.Second;         int month = dat.Month;         int day = dat.Day;         MySqlConnection connection1 = new MySqlConnection(connection);         connection1.Open();         MySqlCommand command = new MySqlCommand ("SELECT * FROM TABLE_Name",connection1);              MySqlDataAdapter dataadpter = new MySqlDataAdapter(command);         DataTable datatable = new DataTable("TABLE_NAME");         dataadpter.Fill(datatable);         datatable.WriteXml("C:\\Users\\Downloads\\agent.xlsx" + time + " - " + time1 + " - " + time2 + " - " + day + " - " + month + "");         MessageBox.Show("export data");        }      }    }   my problem is that when i download file(click import button)its not download an excel file its just an normal file.  how i download it as excel file . if any one know this.... help me

How can I create an Excel spreadsheet with C# without requiring Excel to be installed on the machine that's running the code?


My student said "I watched a TV at home" but I corrected it to "I watched (the) TV at home". I said "the" is not absolutely necessary. My student doesn't understand why "a" is not appropriate. How can I simply explain this? (The student isn't familiar with grammar jargon so I'm trying to make the explanation as simple as possible)

"He was watching the television when I called on him."  When I said this sentence to one of my friends  (an English teacher)  he corrected me saying that the definite article (the) should be omitted. Still, I can't understand why. ? Actually similar  question has been asked earlier but the answers were so ambiguous. So I put complete sentence.


In my studies of Mathematics and (mostly) Theoretical Computer Science I've encountered what is known as  which purports to demonstrate nothing can be actually be proved because all proofs are one of the following:   The circular argument, in which the proof of some proposition is supported only by that proposition The regressive argument, in which each proof requires a further proof, ad infinitum The axiomatic argument, which rests on accepted precepts which are merely asserted rather than defended   My response: What's wrong with circular reasoning in the first place? I simply disagree fundamentally with the notion that we can't have "closed systems" of knowledge. Why is there this idea that we need some kickstarter axioms to prevent going around in circles?  It's not that I don't appreciate the need for axioms from a convenience perspective. It's that I don't think that there's really no merit to going around in circles in the first place! "I am God therefore I am God" is valid. Things don't need to make sense. After all sense is not an inherent property of a statement. It requires interpretation to judge that. Interpretation from another language - in the form of symbolic manipulation. It's all inherently meaningless - so why bother with making sense when you can just be valid. This is my argument for why circular reasoning is a blessing. Instead of hunting down possibly ad infinitum the "source", the most "fundamental" axiom, the "point", we can prevent the existence of the Hydra altogether. It's either circular reasoning, or the same thing in disguise but with more stress on top of it - the difference is that in the latter the circle never runs out. Why choose stress?

Suppose the following dialogue:  ... "I accept only one notion of land property. Namely, 'I am doing my stuff here, therefore I am here". "But this means," he responded, "you can break into any place and stay there, using this rule." "There is another rule, though. Right to act in its most natural sense, 'I am here, therefore I am doing my stuff here." "But do not these rules put together become circular reasoning?" "Of course, they do," I put my head closer to him, "and this is exactly that rare case when circular reasoning is not only sufficient, but is necessary." "But why is that? Circular reasoning never was a correct argument." "There are many circular things happening in nature. Life forms, for example, exist only in order to produce new life forms or to prolongate their own lifetime. Is there any reason to say this can't be the case for reason itself? Why must reasoning not be circular?" ...  Can circular reasoning ever be justified? For example, we know all the words in our languages can't be defined using other words without the use of circularity. We know logic can't prove itself without circularity. Are these arguments rational? Are there any other arguments where circular reasoning is still rational?


Is the following good enough to avoid a SQL injection?  mysql_real_escape_string(htmlentities (urlencode($_POST['postmessage'])));

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


I was wondering how the url rewrite on for example this site works. I mean I don´t think that it is done via. modrewrite in apache or nginx. The thing I´m interested about is the id and user friendly title in one. How does it work that if the server enters only the id or the id with a wrong title, it 301 rewrites it to the right one ?  Is there any how to about it I couldn´t find or could you explain it for me with a small example?  For Example:  -index.php |--index.php?page=2 -server.php?id=45343 -contact.php    -example.com/ |--example.com/page/2 -example.com/server/45343/some-random-title-to-be-user-friendly(.html) -example.com/contact(.html)   .  Update:  I would like to know how this works without modrewrite (htaccess..) as I know that e.g. xenforo isn´t using it.

This is a double question: The correct answer will go to "How you do it in PHP" explaining if there is any advantage goes also counts if possible.  I'm just curious because I really don't know and I see it a lot in webpages.  Edit: I don't know the technical name, but for example here on Stackoverflow: "http://stackoverflow.com/posts/edit/522452" is what I mean as "folders" (a term previously used in the title of the question).


I had several pieces of a project in different layers.  After modifying a piece in layer e.g. 4, it was selected, active and in object mode.  I selected 'export', 'stl' and executed.  The file statisics show a very large file, and when I import the stl file, the entire project, from all layers, show up on one layer. What did I do wrong? TIA

In a scene with more than one object, is it possible to export that one object without deleting every other object, exporting it, then undoing the deletes?