Where does Dumbledore learn to speak Parseltongue?

In Harry Potter, it says that Dumbledore can speak Parseltongue. Where is this proved, and where does he learn it?


How to write a loop using scanner that checks INT's and String's

I'm trying to write a loop that uses scanner to add integers to an established integer array list. It has to to be able to terminate the integer entries and proceed once "x" is entered, and prompt the user to re-enter an integer if any other letter is entered. My problem is that using .nextInt() I get run-time errors when entering a String. Am I simply using the wrong scanner method? This is what I have so far. I imported java.util.*  public static void main (String [] args)    {       Square square = new Square(); //constrcutor that establishes array list "square"       Scanner in = new Scanner(System.in);       int value = 0;        while (value != "x")       {          System.out.print("Enter an integer(x to exit): ");          value = in.nextInt();           if (in.nextInt() != "x" || value !> Integer.MIN_VALUE && value !< Integer.MAX_VALUE)          {             System.out.println("end");             System.exit(0);          }       square.add(value);          }    }


When water climbs up a piece of paper, where is the energy coming from?

Take a glass of water and piece of toilet paper. If you keep the paper vertical, and touch the surface of the water with the tip of the paper, you can see the water being absorbed and climbing up the paper. This climbing up is intriguing me. Where is the energy coming from?  Supposedly, a lot of water molecules are moving up and gaining potential energy. This has to be balanced by something. I can think of a few possibilities, but I can't tell which one it is.   When the water molecules dilute into the paper, they are at a state of lower potential binding energy. Some molecular interaction (van der Waals?) is at lower energy when you have a water+paper solution, compared to a water-only solution. This compensates the gain in gravitational energy. The surface between the paper and the water is at lower pressure than the atmosphere. This causes the water to be pushed into the paper by the atmospheric pressure, up until the point that the column of water above the surface is heavy enough to counterbalance. The potential energy would be a result of work done by the atmosphere. Some water molecules climb up randomly and loose kinetic energy going up, and somehow get "stuck" up there. Something else?


Why are the upvote and downvote buttons visible on a user's own post?

I saw, when I posted a question on Stack Exchange/Stack Overflow, there are upvote and downvote buttons for our post. But we can't upvote nor downvote the post. Why didn't Stack Exchange remove it for our own posts?  Any reason why they didn't make the upvote button viewable for other users only? Not the user who posted the question/answer?


How much is a traveler affected by Ramadan in Indonesia?

I'm planning to go to Indonesia this summer. However, Ramadan, where Muslims have to fast during the daytime, is going to be from June 18th to July 16th this year (2015).   I'm planning to go to Bali, Java, Sumatra and Sulawesi. Except for Bali, all of those regions are predominantly islamic. I have heard that during the last week of Ramadan and the following week, most Muslims in Indonesia are on holiday and are visiting their home towns and families and that thus public transport is very overcrowded during this time.    How much is a traveler/backpacker affected by Ramadan?


How can a Druid get an animal companion?

I was wondering whether or not there is any non homebrew method other than multi-classing, for a druid character to get an animal companion. If not I would appreciate some advice for implementing the animal companion feature  to the druid class without breaking the game too much.   I am asking because the character I wish to play will be a fire genasi druid who was born to a highly religious family who thought he was a demon or other, and abandoned him in the woods, he was raised by wolves and then trained by a druid, and I want to be able to have a wolf that was different from the others in the pack (a genasi is the result of a genie and a mortal, so does a wolf count as a mortal?) as a companion.


Why is the range of inverse cotangent only positive?

Is it because of conventions or some practical reason?  Some websites say it is conventions while other websites say it is because of making it a function.  Thanks!


How do I find my home in Minecraft after recovering corrupted saved world data?

Help please. Our computer crashed and the world where my son had built his house vanished. I followed instructions I found on minecraft.gamepedia.com for recovering corrupted saved world data - replacing the following with ones from a new world -  level.dat level.dat_mcr (not always present) level.dat_old session.lock    This seemed to work but we couldn't find the houses we'd built or the lava pillar we built to mark the spot. We've flown around in all directions for long distances and found nothing. I didn't know about F3 and coordinates before we lost the world so we don't have any for our houses. There are beds in the houses but I'm not sure if we ever slept in them as we couldn't figure out how that worked and we're in creative mode.   Is there any way to get the coordinates for our houses from the saved files for the world? Sorry if this question is not asked well - I'm a bit lost in this stuff but trying to recover it for my young son.


How does a new user begin using Stack Overflow/Stack Exchange?

As a new user, I find it impossible to contribute to the community or to even begin contributing. I know why the reputation system is in place and I respect it, but at the same time it is too hard on new users.  It started with me wanting to upvote a question...     "Vote Up requires 15 reputation"   Just to appreciate a good question that helped me I need 15 rep? OK..., so I find out how I can get reputation points. More or less, I need to ask a question for +5 and add an answer for +10. I don't have any questions at the moment and I don't want to spam a random question, but I did happen to have a slightly different answer to the earlier question that I wanted to upvote. So I try to answer...     This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site.   Now... I know this doesn't apply to every question, but at the same time, this means I'm forced to answer yet another question, and I don't want to go around looking for random questions and spam irrelevant answers...  Now I'm stuck. So I try to talk to some other users in the chat rooms about how to go about getting reputation points and how they first started. I entered into a "casual chat room".     You must have 20 reputation on Meta Stack Overflow to talk here.   Yes... I can understand why this is enforced, because we don't want new users to spam chat rooms, but all I wanted to do was ask for help. So I can't even talk to anyone about my newbie problems. So okay, I'll just settle for upvoting comments in the question that helped me. I don't see an upvote hover-over button so I can't even do that.    So now I'm stuck at 1 reputation point, unable to cross that 15 rep barrier, and even after posting this question I'll only have 6 rep points and still unable to do anything, and I'll be forced to look for questions to answer. Yes, I should be contributing to the community, but I shouldn't need to begin answering or making questions to upvote questions and answers. This only spurs more spam/irrelevant answers if anything.   Very, very, very new-user unfriendly.


Definition of time & its connection with movement of material. In physics we deal with material & without material time cannot be imagined

We get different definition of time? the indefinite continued progress of existence and events in the past, present, and future regarded as a whole. Time in physics is defined by its measurement: time is what a clock reads. In classical, non-relativistic physics it is a scalar quantity and, like length, mass, and charge, is usually described as a fundamental quantity.  But in physics can we have a deep answer?


How do they film the mirror scenes in movies?

It always makes me wonder how do they place the cameras and crew members while filming a scene which is opposite to a reflecting object, such as mirror.  Because, when filming the reflected objects we should see the camera and cameraman because of their reflection.  But this does not happen in the movies.  How do they film the scenes with an actor facing a mirror?  Why don't we see the cameras and crew?  What is the technique they use to film the scenes with reflecting objects?


How to generate a URL for ASP.NET MVC action, including hostname and port?

My current request is:        I want display an action url in asp.net view layer, url is like this(full url, including http://protocol + hostname + port + controllerName + actionName):


Action of finite group of automorphisms on Spec A

Question 2.3.20 in Qing Liu's Algebraic Geometry and Arithmetic Curves:  Let $A$ be a ring, $G$ a finite group of automorphisms of $A$. Let  $$    p: \mathrm{Spec}\ A \to \mathrm{Spec}\ A^{G} $$  be the morphism of affine schemes induced by the obvious inclusion.     Show that, for $x_{1}$, $x_{2} \in \mathrm{Spec}\ A$,    $$ p(x_{1}) = p(x_{2}) \iff \exists \ \sigma \in G : \sigma(x_{1}) = x_{2}.$$   The '$\impliedby$' direction is easy, but I'm having trouble with the other direction (although I have no doubt that it is also simple).   My attempts so far have included assuming that there is no $\sigma \in G$ such that $\sigma(x_{1}) = x_{2}$, so that for each $\sigma$ there is $g_{\sigma} \in x_{1}$ with $\sigma(g_{\sigma}) \notin x_{2}$, and then trying to construct an element of $p(x_{1})\backslash p(x_{2})$ out of these $g_{\sigma}$, for example by taking $$   g = \prod_{\sigma \in G}g_{\sigma} $$ and then  $$   h = \prod_{\sigma}\sigma(g) $$ but this appears to fail as I can't ensure that $\sigma(g_{\tau}) \notin p(x_{2})$ for $\sigma \neq \tau$.  Any hints would be much appreciated!


How to prevent pagebreak for a custom environment?

I use the following custom environment emailHeader and  (credits belong to ).  \definecolor{emailHeaderBackground}{RGB}{225,225,225} \usepackage[framemethod=tikz]{mdframed} \newmdenv[   skipabove=0em,   skipbelow=1em,   hidealllines=true,   backgroundcolor=emailHeaderBackground,   roundcorner=3pt]   {emailHeader}   In the document ...  \begin{emailHeader}   \emailFrom[John Doe]{john.doe@stackexchange.com}   \emailSubject{Re: Please do break apart}   \emailDate{Wed, 22 Aug 2012 12:23:18 +0200}   \emailTo[Jane Doe]{jone.doe@stackexchange.com}   \begin{emailsCc}     \email[Barack Obama]{barack.obama@whitehouse.gov}     \email[Michelle Robinson]{michelle.robinson@whitehouse.gov}   \end{emailsCc} \end{emailHeader}   The output looks like this ...    I use the environment several hundred times in the document. Sometimes it happens that the email header is at the end or beginning of a page. Then, it breaks into separate lines. As you can see the environment is not a verbatim environment for which I found settings to avoid the page break.    Question:  How can I prevent a pagebreak for the above environment? I want the command to be added to the environment definition. I do not want to edit all the places where I use the set of commands.


How do I match a user input string to anything and everything that means localhost?

I need to tell if a user entered the local machine's name in a textbox. This turns out to be trickier than I originally thought.  string userInput = inputTextbox.Text.ToLower(); string machineName = Environment.MachineName.ToLower();  bool isLocal = userInput.Equals(machineName ) || // This is what we started with...              userInput.Equals(".") ||             // Then we added this...              userInput.Equals("localhost");       // And then we added this...   As you can see, it's gotten quite messy and unmaintainable. For example, the address 127.0.0.1 wasn't included. Our testing department keeps writing bugs every time they find a new name for home. We need to squash this bug once and for all.  Is there an easier way to do this?


Solving for a pdf of a function of a continuous random variable. Justification and reason for the procedure

Short version: When solving for the pdf of a function of a continuous random variable(say, $Y=X^2$), why can't you just plug in inverse of that($\pm\sqrt{x}$) into the pdf of the RV? Why do you have to start from the cdf of the $Y$, substitute $Y$ with $X^2$, and differentiate that to get the pdf?    The point of this question is regarding the intermediate step involved.   Why is it not allowed to simple plug-in to the pdf of RV?   why is necessary and also justified to do so involving the cdf?   Long version : Let's say you have a random variable $X$ and a function of the random variable, $g(X)$ (such as $Y=X^2$). You are interested in finding the pdf of $Y$, i.e. $f_Y(y)$.   Usually, to do this, you have to start with the cdf of $Y$ first, and differentiate that to get a pdf of it. For example,    $$F_Y(y)=P(Y\le y)$$ and here you substitute $Y$ with $X^2$:  $$P(Y=X^2 \le y)=2F_X (\sqrt{y})-1$$  and you you differentiate this to get pdf of $Y$ $$d(2F_X(\sqrt{y})-1)/dy=f_Y(y)$$  My question is : WHY? why not just solving for $$f_X(\pm\sqrt{y})$$ what is wrong with this approach? and why is it justified to use cdf to solve this?  Please explain this in a layman's term since clearly I am a novice in statistics


How to draw a pyramid with height and slant heigth with TikZ?

How to draw a pyramid with height(altitude) and slant heigth with TikZ. According to the figure


Show that the solution for the Diophantine equation $x^2 - y^2 = N$ is unique if and only if $|N|$ or $\frac{|N|}{4}$, respectively, is $1$ or prime.

Show that the solution for the Diophantine equation $x^2 - y^2 = N$ is unique if and only if $\mid N \mid$ or $\frac{\mid N \mid}{4}$, respectively, is $1$ or prime.   I have an idea of how to show $\mid N \mid$ or $\frac{\mid N \mid}{4}$ is $1$ or prime $\Rightarrow$ the solution for the Diophantine equation is unique.  We can show this by going through the separate cases $ \mid N \mid = 1$ or $p$ and $\frac{\mid N \mid}{4} = 1 $ or $p$. For example, if $\mid N \mid = 1$, then $x^2 - y^2 = (x -y)(x+y) = 1$ or $(x -y)(x+y) = -1 $. For $(x -y)(x+y) = 1$, we have $x = 1, y = 0$ and $x = -1, y = 0$ as solutions (more than one solution? Doesn't uniqueness imply only one?).  How do I show the other direction?: The solution for the Diophantine equation is unique $\Rightarrow$ $\mid N \mid$ or $\frac{\mid N \mid}{4}$ is $1$ or prime.


Distribution function of X-Y for normally distributed random variables

I have two independent normally distributed random variables $X,Y\sim \cal N(\mu,\sigma^2)$ and want to calculate the distribution of $X-Y$. I tried with $F(z)=P(X-Y \leq z)$ but failed. Does anyone has an idea how I approach it?


Given time series forecast and associated confidence interval, how to calculate the total return's confidence interval

Suppose I bought 12 widgets for a set price, and I am able to sell one widget per month for the next 12 months. Also imagine that I have a monthly ARIMA forecast with confidence intervals for the price of a widget for this time period. How would I calculate the confidence interval around the expected profit from my widget sales? I don't think I can treat this probability distribution of a sum of 12 independent normals because each month has dependence on the prior months. Is there a good way to calculate the total profit's confidence interval given these inputs and the historical time series? Simple graph for reference:


Gmail does not accept mail from a new server

I am setting up a new server and discovered that Gmail does not accept emails from this server.  I checked Exim logfiles and found the following:  Our system has detected that this\n550-5.7.1 message does not meet IPv6 sending guidelines regarding PTR records\n550-5.7.1 and authentication. Please review\n550 5.7.1 https://support.google.com/mail/answer/81126 for more information. om7si10023450wjc.42 - gsmtp   My server has IP4 and IPv6 ip addresses. I have added SPF records for both IP4 and IPv6 IP addresses. The only thing is that I don't have PTR records yet (my data center does not allow to add PTR records if A record does not point to the same server). So, I will PTR records later when I move websites to the new server.  My question: is it possible that Gmail does not accept emails just because I don't have PTR records? All email providers in similar situations just put emails in Spam or Bulk mail folders. Gmail does not accept mails at all?


Is there a way to predict a decay chain? Let's say I have U-238 and want to find out its decay chain, is there a way to do that without looking it up? Thanks in advance.


Newish Windows 10 installation taking ~ 20 minutes in the pre session init phase

I installed Windows 10 on my Dell Precision T5400 a little over a week ago. It is a pretty old computer but it has two physical 4 core xeon processors, 32GB of Ram and a Crucial 525GB SSD. It is very speedy once it gets booted up and I have been using it for doing video editing and playing around with the new linux subsystem built in. The lengthy boot time is very inconvenient though. When installing it took forever to boot and each subsequent time has taken forever to boot. I actually thought it was just installing updates the first few times. I recently started trying to diagnose and repair the problem and I have only been able to narrow the excessive boot time down to the pre session init phase. I would also note that it takes just as long to do a safe mode boot without networking. I downloaded and installed the performance recorder tools but beyond seeing that it is something in the pre session init phase I am at loss as to what to do next. If someone could help steer me in the right direction I would greatly appreciate. I am unsure how to post the logs in this post but I will be glad to with some instruction. Thanks again in advance.


text spacing of tables numbers in list of tables

I just use documentclass(report) and \listoftables. And my tables in the documents have so long names for section name, like III.3.1.1 , and so on. So, when i compile the tex file, it became like this :    any idea to fix that? Thank you.


I have applied for a United Kingdom visit visa but I did not sign my application. I do not know if it will be rejected.  Is there any chance they will accept my application? I'm really tense about that so please advise me. What should I do?


How do I disable 'Activities' hot corner in GNOME shell?

GNOME shell has the so-called feature "hot corner", that opens the dashboard  if the mouse touches the top-left corner of a monitor screen.  I want this disabled I used to have a GNOME shell extension, yet the repository is not found anymore:  git clone git@github.com/Ahrak/gnome-shell-extension-disable-hot-corners.git fatal: repository 'git@github.com/Ahrak/gnome-shell-extension-disable-hot-corners.git' does not exist


Validation Rules: Only the status field can be edit

I need a validation rule that prevent user to edit the record when the status is "under approval", however the status can be edit to other values. I tried the formula above, but the syntax is wrong. I'm pretty new on validations and I don't understand this very well. :( Someone can help me on this?  AND( ISPICKVAL(  Status__c  , "Under Approval") ,       NOT( ISPICKVAL( PRIORVALUE(Status__c) , "Approved"),            ISPICKVAL( PRIORVALUE(Status__c) , "Paid"),           ISPICKVAL( PRIORVALUE(Status__c) , "Rejected"),            ISPICKVAL( PRIORVALUE(Status__c) , "Unpaid")          )


i've written chmod 755 /etc/ and chmod 0644 /etc/ and now i find myself without access to anything,and inside the terminal where before there was username@system1: now there's I have no name!@system1: . I know i messed everything up,but there's a solution? a way to restore the default configuration? I Cannot reinstall,so i've to repair..


When is swap memory useful? Why do we need to set it to twice the amount of RAM?

I know that memory will be swapped whenever RAM usage is high. And I read that we need to set swap to be twice of the amount of RAM. But why? How will it shift from RAM to swap? If we do not have swap what will happen?


How to use less in a script without getting ESC escape characters?

When I use less at the command line the output is like   but when I use less from within a bash script I get:   How can I use less in a bash script and not get all the escape characters and have it work like it does at the interactive command line?


Ability to install Ubuntu on Asus PU500CA

I'm going to buy and start using Ubuntu on Asus PU500CA  with i5 processor () and wanted to ask you for advice - doesn't it seems that it'll work OK on this laptop, or some of its hardware seems to work not quite OK?  Thanks a lot!


The answer at  says that $a|x$ and $b|x$ implies $\operatorname{lcm}(a,b)|x$. I can see that if $a=\prod p_i^{e_i}$ and $b=\prod p_i^{f_i}$ where $p_i$ is the i-th prime, and $\operatorname{lcm}(a,b)=\prod p_i^{max(e_i,f_i)}$ then this kind of shows the result because $x$ has to have prime powers at least $\max(e_i,f_i)$. Is there a way to more directly and/or explicitly motivate this conclusion?


What is the ’s-possessive form of "the king of Troy, Priam"?

“This was brought about by the king of Troy’s, Priam’s, death.”   In this sentence, should the ’s be tagged on to “the king of Troy”, “Priam”, or both?


How to allow non-root users to run certain programs (for example the KDE app store) without root

Put simply, Whenever somebody logs onto the family computer that I manage, I get bugged about updates and "could you install x thing that I saw in the store" and such. How would I enable all users to run flatpak, snap, and plasma-discover without root? All questions about this that I have seen previously seen only cover running one command without root access.  does not answer my question as it addresses allowing a user to run a single program without root access.


AUC ROC Threshold Setting in heavy imbalance

I am doing binary logistic regression on a dataset with very heavy class imbalance. Class 1 is only 1% of data. When I train logistic regressor without class weights I get ROC AUC Score of 0.6269. Which is decent. However, when I see my confusion matrix I see that my model never predicted any 1's at all. So why is my AUC so high? I though AUC is meant to be a good measure for such a case.   Confusion matrix  Predicted      0    All True                    0          32109  32109 1           1223   1223 All        33332  33332   I know Confusion matrix makes the probability threshold 0.5, so is score saying there is some threshold for which model will give higher recall? How can I get this threshold?            Class  precision    recall  f1-score   support             0       0.96      1.00      0.98     32109            1       0.00      0.00      0.00      1223   I only care about precision and recall of class 1.


Is there a useful interpretation of variance as a special case of covariance, Var(X) = Cov(X,X)?


How to create a DSL Connection in network-manager in Ubuntu 17.10

In 17.04 I could create DSL Connections in the network settings. In 17.10 the option is not available anymore. How can I create a DSL connection?


I have made a bootable USB. I have made 100s of them before. I have a dual boot pc, Kali and Ubuntu.  I want to reinstall Kali from USB (alongside my UBUNTU), but the computer will not boot to USB anymore. Burning ISO to DVD is really absurd.  Why can't I boot to USB anymore?  USB is disabled in bios, yet I use the USB ports everyday. Everyday. It is an Ubuntu question.   I can't and won't install Ubuntu on my laptop if I know I'll lose USB boot. This isn't a BIOS question.


I randomly found the  tag. It seems meaningless both relative to the submitter's code (of course there is a bug in it) and third-party code (only a bug if an answer says so).  I am not sure who has the permission and what the process for this, but I suggest to delete and block that tag.  Actually I just found a similar question, , however there is no authoritative answer on why it still exists.


Award Mortarboard and like-badges after serial voting check

Today, all of a sudden, I noticed my rep climbing:    Now I figured this was going to be reversed soon but then I noticed I got the Mortarboard badge for having hit the rep cap. I figured that the user must have been clever with the serial voting and got around the auto-detection script.  After a couple of hours when I went to check, I got the "Voting corrected" item in the list, but I still have Mortarboard.  After reading , I understand why I still have the badge. I would suggest that this badge (and any badge that requires votes that can be gained from serial voting) shouldn't get awarded until after the serial voting check has been done. This way, getting the badge feels more rewarding because you know that people have honestly up-voted your useful posts.


Since List is an interface and how we are creating instance without any anonymous class

In java collections, Since List is an interface and how the "new" keyword is used to declare it without any anonymous class.  Please explain how the following line works. List listTry= new ArrayList();  How the instance is created for ArrayList interface.


Is it possible to use C++ with Unity instead of C#?

The title kind of says it all. Is it possible to replace C# with C++ on a game using Unity?


passing data from a public method to a private method error

I'm creating a bluetooth application and I'm trying to send a data to a private method from a public method but i got this error     java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference   the public method:  public void showTimeSet(long interval, Context context){     if(interval !=0){         Toast.makeText(context,"Countdown second is "+interval,Toast.LENGTH_LONG).show();         String msg= String.valueOf(interval);         try {             sendMessage(msg);         }catch (Exception e){             Log.e(TAG, "showTimeSet Error sending message: "+e);         }     } }   and the sendMessage method:  private void sendMessage(String message) {     // Check that we're actually connected before trying anything     if (mChatService.getState() != BluetoothService.STATE_CONNECTED) {         Toast.makeText(getActivity(), R.string.not_connected, Toast.LENGTH_SHORT).show();         return;     }      // Check that there's actually something to send     if (message.length() > 0) {         // Get the message bytes and tell the BluetoothService to write         byte[] send = message.getBytes();         mChatService.write(send);          // Reset out string buffer to zero and clear the edit text field         mOutStringBuffer.setLength(0);         mOutEditText.setText(mOutStringBuffer);     } }


Configuring Python to avoid conflict with ArcGIS for Desktop (ArcPy)?

I am trying to find the best way to configure a new version of python in my computer (windows) so that I do not have any problem with the python version that I have with ArcGIS. Is there anyway to have two versions of python and install/run anything on version 2 (say version 1 is my ArcGIS version)without having a conflict? I had to reinstall ArcGIS before due to this conflict. I am a beginner in programming and so please be patient if I am not making sense here.


if condition not working for table.getValueAt JAVA swing

I'm experiencing a really strange behaviour of my code. I'm trying to translate a specific column (in this case just a single row) dynamically through a button in java, but for some reason, I'm failing to do so.  String newWord;  System.out.println(table.getValueAt(0, 2)); if(table.getValueAt(0, 2)=="mashkull") { newWord= "male"; } else if (table.getValueAt(0, 2)=="femer") { newWord= "female"; } else { newWord= "other"; } table.setValueAt(newWord, 0, 2);   I populated that specific cell (row = 0 , column = 2) with the string "mashkull" (which in my native language means male, not relevant though). When I click the button once, it prints on my console this:  mashkull   but for some reason, the if condition doesn't work properly with table.getValuAt method...yes I've tried casting it to (String) or using the String.valueOf method but it's still the same. And as you can see, it does print mashkull on the console, it just can't get verified by the if condition, but it goes to the else statement and runs:  newWord= "other";   And the next thing I see on the JTable I created is the word "other" instead of the word "male" . If I click the button again (if I run the same code for the second time) it writes a new line on it and that is:  other   Any idea of where's the problem? Even though I am casting the value of that cell to string it still doesn't work, is there any detail I need to know about the method table.getValuAt(row, column) or about casting?


Show that $$\lim_{(x,y) \to (0, 0)}\frac{xy^2}{x^2+y^2} = 0$$  I have tried switching to polar coordinates but I'm not getting a single term.  This is what I did.   Putting $$x=r\sin θ,\quad  y=r\cos θ$$ we obtain   $$\left|\frac{xy^2}{x^2+y^2}\right|=|r\cos^2 θ \sin θ|                        =|r\sin θ(1-\sin^2 θ)|                        = |r\sin θ-r\sin^3 θ|$$


I found a skeleton horse that had spawned(No lightning/storm), and I tried to ride/tame it and it doesn't do anything

So I got on my mc windows 10 edition survival world and I found a skeleton horse that had spawned for whatever reason(No lightning/storm), and I tried to ride/tame it and it doesn't do anything. I don't even know why it spawned, I didn't use cheats or anything either. It did however spawn in my nether portal room so it could of possibly came out of the nether?


In the study of Newtonian stellar structure, Weinberg (1972) writes     The uniform  dilation of a sphere with uniform density will give it a kinetic energy   $$U=\frac{3}{10}M\dot R^2$$   I don't know how to derive this, or even really where to begin. Does one resolve the sphere into particles or somehow treat it as a continuum? I'm quite stumped and several online searches have not been fruitful.   So, how does one derive this?  Thanks.


I've been reading through a course on exponential functions, starting from integer-valued exponents to rational ones as in: $x^r$ from $r\in \Bbb{N}$ to $\Bbb{Z}$, and combining them to rigorously construct for $r\in\ \Bbb{Q}$. Still, this book adresses high-schoolers, and therefore "summons" an extension of the exponential notation for real exponents. Is there any formal basis for this extension? Could it be related to the density of $\Bbb{Q}$ in $\Bbb{R}$ ? Or the limit of a sequence $(x^{(r_n)})$ where $(r_n)_{n=1}$ is a sequence of rationals that converge to $r$ a non-rational exponent?


Android Facebook Version 3.4 - Sort News Feed

My Samsung Galaxy S 3 just updated to Android Facebook Version 3.4.  I cannot figure out how to sort News Feed by most recent?


14.04 Thinkpad T450: Text getting messed up on large screens

I am running Ubuntu 14.04 on think-pad T450.  When using an external monitor with higher resolution than the in-built laptop screen, the text of dialog boxes are getting messed up.  Looks like I need to replace the Graphic card driver. Anyone found a solution to this?  Updated to add requested information:  lspci -nnk | grep '\[03' -A2   gives the following:  00:02.0 VGA compatible controller [0300]: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09)     Subsystem: Lenovo Device [17aa:5034] Kernel driver in use: i915   Below is a screenshot, see how the letters are messed up on the screen.


Problem understanding Lorentz invariance

So they usually started with "...This is obviously Lorentz invariant, because of the 4-vector character of the quantity,..., (and after a two page long derivation) another quantity is also obviously Lorentz invariant". I have encountered this problem a lot of times in several physics textbooks.  I feel they are implying that as long as a quantity is a tensor, it is automatically invariant. But is there a formal way of knowing/proving this?  For example:     $$\int d^4 p \: \delta \left( p^2 - m^2 \right) \, \theta \left( p^0 \right) = \int \frac{d^3p}{2E_{\bf p}}.$$   "The relation shows that the expression $d^3p/2E_{\bf p}$ is Lorentz invariant."   How do they see this?


I installed a package from Sentellic, called fspc but seems I can't install it due some dependencies, how to correctly install it?


I'm having a hard time to decide between the correct form. Is it "help us decide" or "help us to decide"? Please also state the reason for your answer. Thank you very much!


Why does "north" come before "south", and "black" before "white"?

This website is common in both north and south America.   Or is this better?     This website is common in both south and north America.   Let's ask Google:   : 26,800,00 hits : 592,000 hits   Why there is a huge difference?  There are too many other examples, such as white and black, high and low, etc.    In an academic/professional writing context, if there is no logical reason for any order, should one just preserve the common order? Does using the uncommon order look strange?


Can I install Windows 8 onto a Storage Spaces Pool

I am going to perform a clean installation of Windows 8 Pro onto my computer.  Due to upgrades over time I currently have 2 x 120 GB SSD drives.  Is it possible to create a Storage Space Pool using both SSDs as part of the Windows 8 Setup and use that pool as the System drive?


Sorry if I am asking this question that has been already asked, but I am kind of a noob at programming, I tried researching how to fix this bug but I am still having trouble trying to solve it. I am trying to compile this block of code here:  //Default constructor public Game () {     potAmount = 100;     betAmount = 0; }  public int getBetFromUser() {     //Introduction to the game     System.out.println("Welcome to Solitaire Dice Game..bet an amount\r\n" +              "\t-if you roll triples you win triple your bet,\r\n" +              "\t-if you roll doubles you win double your bet,\r\n" +              "\t-if you roll 10 or over, you keep your bet\r\n" +              "\t-otherwise you lose your bet\r\n" +              "A bet of 0 ends the game\r\n");     System.out.println("Your current pot is 100");     System.out.println("Enter your bet amount:");     betAmount = keyboard.nextInt();      return betAmount;   And I am trying to call it in my main class but I get this compile error:  Enter your bet amount:  Exception in thread "main" java.lang.NullPointerException     at Game.getBetFromUser(Game.java:26)     at Assign3.main(Assign3.java:9)


I'm having troble with this problem, I don´t know what to do, is for a final exam tomorrow.  Let $f:R^2\to R$ given by  $(y-x^2)(y-2x^2)$  a) Draw the sets $A=${$(x,y)$|$f(x,y)>0$}$\ and\ $$B=${$(x,y)$|$f(x,y)<0$}  b) Shows that for all $\vec u$=$(u_{1},u_{2})$ with ||$\vec u$||=$1$, the function: $g(t)=f(t\vec u$) has a local minimum in $t=0$  c) Shows that notwithstanding the foregoing, $\vec 0$ is not a local minimum of $f$


Why doesn't running "sudo shutdown now" shut down?

When I issue the following:  sudo shutdown now   ..my newly commissioned Ubuntu 14.04 server doesn't shut down. It stops with the following message:  * Stopping System V runlevel compatibility Give root password for maintenance: (or type Control-D to continue):   If I type in the root password, the machine simply sits there at the shell prompt.


How can I arrange words into a shape to make a "word cloud" design?

I want to create a T-shirt to commemorate the tenth edition of a gaming convention and I had the idea to have the names of all the games that were played during the convention form a big roman numeral X.  I'm looking for a free program, app or plugin that allows me to insert chunks of text (the names of the games) and automatically sorts them to fit the shape as nicely as possible, without mixing the words in the same chunk (but if they continue on the same or on the following line it's ok).  Multi-directional words forming the shape is ok too but those usually make some words too small for the t-shirt printer.  Do you know a program that can create such a thing?  I can easily work with the image of an X or even a raster image.


i have following code where i m including my title and description for the page But google crawled only title not the meta description from the code. Where as meta description was read from the keywords present in html of the page.. Please guide me guys where i m coding wrongly  <!DOCTYPE html>  <html> <head> <title>title inserted here</title> <meta http-equiv="Content-Type" content="text/html;charset=utf-8"> <meta name="description" content="description here"/>


need to make password less login for same linux server with same user

I need to make passwordless login for same linux server with same user.  [airwide@eir ~]$ hostname -i 10.3.7.73 [airwide@eir ~]$ ssh airwide@10.3.7.73 airwide@10.3.7.73's password:    how can make to passwordless for same server?


How to prove the following with induction?  $$\sum_{k=1}^{2n} \frac{1}{k(k+1)} = \frac{2n}{2n+1}$$  I have difficulty solving this example. I got past base part where I prove that $L(1) = P(1)$ but I cant prove it for $n+1$. Any ideas how to deal with this kind of example?


How do you rotate an object so that a particular face is parallel to the ground?

How would I make the face of an object parallel to the ground? I could just eyeball it and use the rotate tool, but it probably wouldn't be perfectly flat. Is there a way I could possibly snap the face of the object I want level to the top of a block (making it parallel with the block) and then delete the block?


I'm browsing , and I found a curious thing:  /// <summary> /// The namespace that the rule is contained within. /// </summary> private string @namespace;  // [...]  internal Rule(string name, string @namespace, string checkId, string context, bool warning) : this(name, @namespace, checkId, context, warning, string.Empty, null, true, false) {     Param.Ignore(name, @namespace, checkId, context, warning); }   What is this thing? Is it just a simple field where at-sign is used to indicate that it is a field, and not a namespace keyword? If so, may at-sign be used for any reserved word (for example @dynamic, @using, etc.)?


$WARNING:$ I am not a mathematician and I am asking this out of my curiousity. This question may have inappropriate tag. $BACKGROUND:$ I have tried many things to find the value of $(1/2)^{(1/3)^{(1/4)^{...}}}$ At last the only thing I could do is to approximate the expression in wolfram alpha and it seemed that this thing does converge (But I'm not sure). $QUESTION:$ If there is any closed form please help me derive it.


On Ubuntu if I type man 2 time I get,  NAME        time - get time in seconds  SYNOPSIS        #include <time.h>         time_t time(time_t *tloc); ...   I get that this works because time is the name of the function, but sometimes I don't know the name of the stuff, I just remember the file. Like say I know what I want is in stdint.h, but I can't remember the identifying thing -- or even worse it's not a function (as is the case when I wanted the docs for ptrdiff_t), how do I find the docs on this header file?  At the bottom of man 2 time it says,     COLOPHON This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the latest version of this page, can be found at .   The . What package has these man pages so I can peruse offline? Why do I have the page for time.h, but not for stdint.h?


Update MacbookAIR Firmware without original hard disk

I got original SSD broken. My MacbookAir 7.1 got only YOSEMITE Internet Recovery. Now, I've bought a SAMSUNG 970 NVME M.2 disk and the system could recognize it using NVME kext patched but cannot boot because my MacbookAir was never updated with HighSierra (and so, no BootROM upgrade is done.With High SIERRA NVME disks become bootable)  Do you think this tool could help me?   Other way to follow?   No way to boot the disk using CLOVER or reFIND for the moment. (am I missing something?)  The only thing I've done is reinstalling YOSEMITE successfully directly to external drive using Internet Recovery, but when trying to update to HighSierra or Mojave the NVME disk and the external one are both unselectable due to "missing firmware"


Skype app in my Ubuntu system work perfectly. But today when I run the app, I see this:    How Can I fix this?


I'm using the caption package.  I want to say  \caption[My short Caption] {My longer longer caption}   and have both show up? How can I do that?


Installation error - PostGIS on Ubuntu 18

I have installed PostgreSQL 11 on Ubuntu 18 and while creating PostGIS extension it gives this error.     could not load library "/usr/lib/postgresql/11/lib/postgis-2.5.so":   /usr/lib/postgresql/11/lib/postgis-2.5.so: undefined symbol:   AllocSetContextCreate   The command I used to download PostGIS   apt install postgis postgresql-11-postgis-2.5


How to exclude specific tables from list of tables?

I made a copy of the latex document here Right now I have two tables, one being used in the title.tex for names and second in the revision_history.tex. I am trying to remove these two tables from the LOT so I can start the numbering from 1 for the actual table in the documents. Basically I want to tell Latex which tables are NOT tables and to just ignore them.


PCA, correlation of the features of projected data

I have just got familiar with some methods of dimensionality reduction, and one of them was PCA. So we have data $X\in \mathbb{R}^{n\times n}$ and want to reduce its dimension to $k$. PCA just takes the covariance matrix of our data, and choose $u_1, u_2, ..., u_k$ eigenvectors of the covariance matrix, so that $ \lambda_1 \geq  \lambda_2 \geq ...\geq \lambda_k \geq ... \geq  \lambda_n$, and projected our data to the $k$ dimension subspace with axes $u_1, u_2, ..., u_k$. As I have seen in some practical examples the covariance matrix of the projected data is diagonal, in other words the features of projected are not correlated. So I want to know whether it is true for all cases, and if it is true, some mathematical proof of it.


Does the recursive sequence $a_1 = 1, a_n = a_{n-1}+\frac{1}{a_{n-1}}$ converge?  Since the function $x+1/x$ is strictly monotonic increasing for all $x>1$, I don't think that the limit converges, but I'm not sure. Can anybody tell me whether the sequence is converging or not?


Are Playstation 4 games locked to a certain region?

This question has been asked before, but it was for PS3 and Xbox 360 and was asked August 2010. This time around my question goes specifically to PS4, since I'm moving from Mexico to Europe and I was wondering if the European games will run in my console or if I'll have to buy a new one. I never thought of this before (which is why I never paid attention if it was mentioned in reports or specs of the console) and the research I did wasn't too helpful.


Moving from SQL 2005 [SQL_Latin1_General_CP1_CI_AS] to 2008 - will I lose any features by using 'backwards compatibility'

We're moving from SQL 2005 [Instance and DB have collation of SQL_Latin1_General_CP1_CI_AS]  to SQL 2008 [which defaults to Latin1_General_CI_AS].  I completed a SQL 2008 R2 installation, and used default Latin1_General_CI_AS collation, with the restoration of the database still on SQL_Latin1_General_CP1_CI_AS. The excepted problems occurred - the #temp tables where in  Latin1_General_CI_AS whilst the db was in  SQL_Latin1_General_CP1_CI_AS and this is where I am now - I need advice on the pitfalls now please.  On installation of SQL 2008 R2, I have the option on installation to use 'SQL Collation, used for backwards compatibility' where I have the option to select the same collation as the 2005 database : SQL_Latin1_General_CP1_CI_AS.   This will allow me to not have problems with #temp tables, but are there pitfalls? Would I lose any functionality or features of any kind by not using a "current" collation of SQL 2008? What about when we move (e.g. in 2 years ) from 2008 to SQL 2012? Will I have problems then? Would I at some point be forced to go to Latin1_General_CI_AS? I read that some DBA's script complete the rows of complete databases, and then run the insert script into the database with the new collation - I'm very scared and wary of this - would you recommend doing this?


How can I know if reboot is required after update?

I have 4 servers with Debian Wheezy OS. I have Apticron installed that informs me about updates. Debian updates are realized so often that when I finish to update the last of 4 servers I get new email about new updates on the first server. I try to update all servers when I get a notification but I never know if there is a need to reboot the servers. I have read that if the directory "/var/run" contains file "reboot-required" I have to reboot the server. But I never have seen this file in "/var/run". How can I know when reboot is required? I don't want reboot my servers every time when I install new updates if it's not needed.  I understand that if I update PHP or MySQL, etc I don't need to reboot the server but updates usually contain many "lib...".  Below are 9 updates (I have received this week).  krb5-locales 1.10.1+dfsg-5+deb7u3 libdbus-1-3 1.6.8-1+deb7u6 libgssapi-krb5-2 1.10.1+dfsg-5+deb7u3 libk5crypto3 1.10.1+dfsg-5+deb7u3 libkrb5-3 1.10.1+dfsg-5+deb7u3 libkrb5support0 1.10.1+dfsg-5+deb7u3 libruby1.8 1.8.7.358-7.1+deb7u2 libxml2 2.8.0+dfsg1-7+wheezy3 ruby1.8 1.8.7.358-7.1+deb7u2   I have no idea what is "libkrb,libgssapi", etc. How can I detect if reboot is needed? Please do not suggest to install UnattendedUpgrades to let the servers update automatically because this can cause websites going offline if something updates not correct.


Windows 10 100% Disk Usage after Startup

After startup for 5 minutes my system is very slow. The Task Manager shows that the disk usage is at 100%. (Later this number is around 2-4 %, but sometimes for 1-2 minutes go up again at 100%.)  I searched a lot on Google. For example I read , and also other pages. I opened two topic on Microsoft answer.  and one in Hungarian.  But I didn't found the solution yet. So I would like to ask Community's help. :)  Here the steps I already done:   I disabled everything at startups (including services) and the issue is the same.  I disabled Prefetch and Superfetch, the Baground Intellingent Transmission, Windows Search and Windows Defender but the issue is still persists. I made a health check on HDD, I made defrag and file system error check, but there are no errors. Also I tried to reinstall the HDD's driver. I made a full hardware check up, with no errors. The Windows and all the drivers are up-to-date. I tried a clean start. The issue is the same. I deleted Dropbox and all antivirus. I turned of the MSI mode.      I using also Linux, where this error is not occurs. Good to know, that Windows had 4 partitions, but I deleted 2 of them for the Linux. I don't know what partitions was these but both was only 10 - 20 MB.  I using a Dell Inspiron 15R SE 7520 with Windows 10 Home.  Personally I think it can be the Intel Rapid Store Technology "driver", because the problem started around when I installed it. (However I'm not sure.) And my hardware not supported yet by Intel, so I have no the newest driver. However I deleted Intel's software and driver and the issue is the same.    Thank you in advance for your assistance!


Do compacta in $\mathbb R^n$ have finite Hausdorff measure?

For $A\subset \mathbb R^n$ let $\mathcal H^s(A)$ be the $s$-dimensional Hausdorff measure with respect to the Euclidean metric. The Hausdorff dimension of $A$ is given by $$\dim_H(A) = \inf\{s>0\mid\mathcal H^s(A)=0\}.$$ One of the go-to curiosities in measure theory courses is the fact the middle-third Cantor $C$ set has Hausdorff dimension $\log2/\log3$. This value is easily determined using a self-similarity argument assuming that $0<\mathcal H^s(C)<\infty$ for some $s$. However, verifying this assumption for $s=\log2/\log3$ is not quite as easy. Thinking about this and other self-similar objects got me wondering about a more general question:      For non-empty, compact $K\subset\mathbb R^n$ of Hausdorff dimension $d$, is it automatic that $0<\mathcal H^d(K)<\infty$? In other words, do non-empty compacta in $\mathbb R^n$ have finite, non-zero Hausdorff measure in their Hausdorff dimension?   At first, I thought that the answer must be yes for the extreme cases $d=0$ and $d=n$ where the relevant Hausdorff measures are the counting measure and the Lebesgue measure (up to scaling). However, at some point I realized that I had implicitly assumed that Hausdorff dimension 0 or n would imply discreteness or non-empty interior (which may or may not be true, probably not).   I'm now at the point where I've realized that I have already spent much more time thinking about this than I should have. Hence, I resort to the infinite wisdom of the internet. I believe that the answer to the above question is no in the stated generality, but I'm basically at a loss. Maybe someone on here has something up their sleeve.


Is there a one word synonym for insincere smile?

I'm writing a story in which the last two words are currently "fake smile." It would be punchier if I could condense these two words into one - is there any such word?


$(\mathbb R, \oplus)$ is a group. Define a multiplication with which we get a field. Where $a \oplus b = a + b +1$

I have this problem from the book Real Analysis of Miklos Laczkovich ():     Let $\oplus : \mathbb R \times \mathbb R\to \mathbb R $, where $(a,b) \mapsto a + b +1$. Then,  $(\mathbb R, \oplus)$ is a group. Define a multiplication with which we get a field.   But in the exercise there are no hints. Could anyone help me?


Is there PvP in Diablo 3? How does it work?

From my very limited experience during the open beta weekend I couldn't figure out a way to attack other players during the beta campaign. Is this possible in the release or will multiplayer only reflect on trading and co-operative games?


When does a statistical consultant become a co-author or collaborator?

I am a graduate student in a small department and have become the go-to person for statistics advice among the other students.  I enjoy this but am wondering at what point I should expect, or request, becoming a collaborator on the project.  Pointing someone towards a method, a paper or a book is definitely not worthy of any recognition, neither would a short one-off 15 minute conversation in the hallway.  But what if I help them understand a difficult statistical method or fix some computer code that otherwise might have taken them days or even weeks to achieve on their own?  What if our conversations helps clarify the questions they are asking either statistically and scientifically.  I assume that if I became a co-author, I'd continue to contribute to the project, help write the statistical methods, comment on the full paper, etc.    I'm wondering if I should set up ground rules that I tell people, like, "the 1st 20 minutes are free, but after that, we'll have to talk about long-term collaboration."  Or I could come up with a list of services I can provide and what the expectations are.     This  comments on these issues from the perspective of a full-time statistician.  This  question addresses more general issues about co-authorship.


Assume we have two continuous Normal RV "X" and "Y". how can I show the conditional PDF f(X|Y) and f(Y|X) is Normal?


c++ template putting implemetation into source file instead of a header

So as the title reads, i want to create a template class and put methods/functions implementations into the relative source file. After some research on the internet i found some perplexing solution with something about making an extra file and including it in the header.  I know that it is possible to place all the implementations inside header file and it will work just fine. Also a side question to that is: Is it commonly acceptable as the best solution to place all the implementations inside header or not because in a comparison to ADT in C you kinda want to hide the implementation in the source file, is it the same case right here?  A little example: Lets say i want a 2-D plane of dots that are characters and i want to use the following code.  Point.h  #ifndef POINT_H_ #define POINT_H_  template <class T> class Point {     T* x;     T* y; public:     Point(); };  #endif   Point.cpp  #include "Point.h"  template <class T> Point<T>::Point(){     x=new T;     y=new T; }


USB stick mysteriously become write protected

So, somehow over the weekend, my 1GB USB flash drive has managed to become write-protected.  There is no switch on the stick, so I'm concluding that something has corrupted at some point.  Obviously I can't format it or remove.  The output from dmesg | tail is:  Buffer I/O error on device sdb1, logical block 328168 lost page write due to I/O error on sdb1 sd 73:0:0:0: [sdb] Unhandled sense code sd 73:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sd 73:0:0:0: [sdb] Sense Key : Data Protect [current] Info fld=0x0 sd 73:0:0:0: [sdb] Add. Sense: Write protected sd 73:0:0:0: [sdb] CDB: Write(10): 2a 00 00 05 08 00 00 00 01 00 Buffer I/O error on device sdb1, logical block 328200 lost page write due to I/O error on sdb1   I think the second and final lines are a giveaway to corruption, but I don't know how to interpret this output.  Could someone help to see if this output gives any indication?  I usually eject the drive before removing it, but I may have been lax once or twice.  The data isn't critical, it's just bugging me.  Any suggestions on how to fix it (if the drive even can be) would be greatly appreciated.


how did the epithet "nigger" come into usage?

My research has resulted in theoretical reasons for the usage of the term "nigger", and I have failed to uncover any evidence as to how this nasty little epithet evolved into the usage and connotation it had and has to this day.  When the African slave-trade was in full-swing , my belief is that a good percentage of black slaves  were captured and sold in Nigeria.  If the ship's captain could read, he would probably not be able to pronounce "Nigeria" or "Nigerian" properly nor would he care.  Since a four syllable word is difficult to pronounce anyway for the education level of seamen in the slave-trade of that era, I believe the term was shortened from nigerian to nigger which was easier for them to say.


I had a problem with the keyboard layout changing from PT (I'm Portuguese) to EN automatically with the last Ubuntu updates in Ubuntu 13.10. After Ubuntu 14.04 came out, I formatted my computer and installed the new version.  After that I haven't had any problems until the recent Ubuntu base update 2 or 3 days ago, when I started having the same problem again. I even removed the English keyboard from the Keyboard configurations, left only the Portuguese one, but still, every time I reboot my PC I get the keyboard configured for EN, despite Ubuntu displaying the contrary?  How can I remove this? I don't want to format the PC again and I'm getting really tired of this problem, since it looks like many Portuguese/Brasilian Ubuntu users are having the same problem.


Redirect to a view with contextual filters

I would like to redirect the user to a view with some contextual filters on the submit of a custom form.  For now I use this :   $form_state->setRedirect('view.search.page_1', ['myvalue' => $value]);   But it add "myvalue" like this : /search?myvalue=$value  and what I want is : /search/$value  Thanks


I am having difficulty with the algebra related to a coordinate geometry question.

A line is drawn through the point $A=(1,2)$ to cut the line $2y = 3x-5$ in $P$ and the line $x+y = 12$ in $Q$.  If $AQ$ = $2AP$, find the coordinates of $P$ and $Q$.


i have just a little problems with my DOM after append but i don't know how resolve it  i look several post but with the mouseup and mousedown i did nt find  this my function    $(function() {     var action;     $(".number-spinner button").mousedown(function () {         btn = $(this);         input = btn.closest('.number-spinner').find('input');         btn.closest('.number-spinner').find('button').prop("disabled", false);          if (btn.attr('data-dir') == 'up') {             action = setInterval(function(){                 if ( input.attr('max') == undefined || parseInt(input.val()) < parseInt(input.attr('max')) ) {                     input.val(parseInt(input.val())+1);                 }else{                     btn.prop("disabled", true);                     clearInterval(action);                 }             }, 50);         } else {             action = setInterval(function(){                 if ( input.attr('min') == undefined || parseInt(input.val()) > parseInt(input.attr('min')) ) {                     input.val(parseInt(input.val())-1);                 }else{                     btn.prop("disabled", true);                     clearInterval(action);                 }             }, 50);         }     }).mouseup(function(){         clearInterval(action);     }); });   and this is my append code      $("#dispostock"+cpt).append('
  <button class="btn btn-default btn-info" data-dir="dwn">  </button><input type="text" class="form-control text-center" value="1" min="-10" max="40"> <button class="btn btn-default btn-info" data-dir="up"> </button>
');   the class of dispostock is .dispostock  thanks in advance


I have a file:  -rw-r--r-- 1 michal michal 1679 Apr 24 06:55 acx.php   The owner file acx.php is user michal, so I create cron using:  sudo crontab -u michal -e   My cron:  */10 * * * * php /var/www/html/cron/exchange/acx.php   In log cron I see:  Apr 25 04:10:01 savecoin CRON[9722]: (michal) CMD (php /var/www/html/cron/exchange/acx.php)   I change the permission file acx.php on 777, but it did not help. When I run the cron manually, the data correctly saves to the database. I do not know what else I can change so that cron can write data to the database  I use php7.2, apache2 http server and MySQL database.


I wanted this weight in kg to be rounded to 2 d.p, how would i Do this within a method?  public String convertFromStoneLbsOz(){      EasyIn2 reader=new EasyIn2();      System.out.println("Please enter the weight in whole stones.");         weightInStone=reader.getInt();     System.out.println("Please enter the weight in whole pounds.");         weightInLbs=reader.getInt();     System.out.println("Please enter the weight in whole ounces.");         weightInOz=reader.getInt();          weightInKg=Math.round(weightInStone*lbPerStone*ozPerLb/ozPerKg);          return ("The weight you entered in kg is "+ weightInKg + " kg.");     }


How to cite lecture notes? (and should I even do this?)

When learning a new subject, I would frequently use lecture notes found somewhere in the Internet. When writing a paper (or a master thesis, as in my case, but the rules should be similar, I believe) one should give some reference for used results which are not common knowledge, if I understand correctly. This make me wonder: what do I do if I want to reference a result I found in some notes?  The natural thing to do would be to just add these notes to bibliography. What format would be preferable for this? Note that there will generally not be much publishing information, perhaps not even a definite year and place. (A BibTeX template would be .)  Secondly, is it OK to cite such materials as a reference?


Show that $(2,1+\sqrt{-5})$ is a maximal ideal in $\mathbb{Z}[\sqrt{-5}]$

Let $R=\mathbb{Z}[\sqrt{-5}]$ and $I=(2,1+\sqrt{-5})$ an ideal generated by $2$ and $1+\sqrt{-5}$. Show that $I$ is a maximal ideal.   So I tried to prove that if $a \notin I$ then $(I,a)$ must be the whole ring or the $I$ itself. That is, we can find a combination $ax+2y+(1+\sqrt{-5})z=1$ or $0$ for some $x,y,z \in \mathbb{Z}[\sqrt{-5}]$. Is my thought correct? How should I find such combination?


Median of 3 partitioning taking more time than quicksort in java

I have a quicksort code in java which I want to improve. The improved code should take less time than the quicksort code. However when using my improved code which implement median of 3 partitioning, it takes 400 miliseconds more. Can anybody help me solve this out? if possible, can you suggest me other possible ways to improve my code. I have from 10,000 to 10 million integers to sort.   Quicksort  public void quickSort(int arr[], int begin, int end) {     if (begin < end) {         int partitionIndex = partition(arr, begin, end);          quickSort(arr, begin, partitionIndex-1);         quickSort(arr, partitionIndex+1, end);     }   }  private int partition(int arr[], int begin, int end) {     int pivot = arr[end];     int i = (begin-1);      for (int j = begin; j < end; j++) {         if (arr[j] <= pivot) {             i++;              int swapTemp = arr[i];             arr[i] = arr[j];             arr[j] = swapTemp;         }     }      int swapTemp = arr[i+1];     arr[i+1] = arr[end];     arr[end] = swapTemp;      return i+1; }  }   Improved code  package sorting;   public class improvement {  Clock c = new Clock();    public void quickSort(int[] intArray) {      recQuickSort(intArray, 0, intArray.length - 1);    }    public static void recQuickSort(int[] intArray, int left, int right) {     int size = right - left + 1;     if (size <= 3)       manualSort(intArray, left, right);     else {       double median = medianOf3(intArray, left, right);       int partition = partitionIt(intArray, left, right, median);       recQuickSort(intArray, left, partition - 1);       recQuickSort(intArray, partition + 1, right);     }   }    public static int medianOf3(int[] intArray, int left, int right) {   int center = (left + right) / 2;      if (intArray[left] > intArray[center])       swap(intArray, left, center);      if (intArray[left] > intArray[right])      swap(intArray, left, right);     if (intArray[center] > intArray[right])      swap(intArray, center, right);     swap(intArray, center, right - 1);    return intArray[right - 1];   }    public static void swap(int[] intArray, int dex1, int dex2) {     int temp = intArray[dex1];     intArray[dex1] = intArray[dex2];     intArray[dex2] = temp;  }    public static int partitionIt(int[] intArray, int left, int right, double    pivot) {     int leftPtr = left;     int rightPtr = right - 1;       while (true) {        while (intArray[++leftPtr] < pivot)         ;        while (intArray[--rightPtr] > pivot)        ;        if (leftPtr >= rightPtr)          break;        else        swap(intArray, leftPtr, rightPtr);     }     swap(intArray, leftPtr, right - 1);     return leftPtr;  }   public static void manualSort(int[] intArray, int left, int right) {     int size = right - left + 1;     if (size <= 1)      return;    if (size == 2) {   if (intArray[left] > intArray[right])     swap(intArray, left, right);   return; } else {   if (intArray[left] > intArray[right - 1])     swap(intArray, left, right - 1);   if (intArray[left] > intArray[right])     swap(intArray, left, right);   if (intArray[right - 1] > intArray[right])     swap(intArray, right - 1, right);   }  } }


If I downvote an answer, is the lost reputation visible to others in my profile?

I've noticed that if I downvote an answer, the record of the downvote is visible to me in my profile.  But when I view my profile from another browser that's not logged into Stack Overflow, I've noticed that I don't see the record of the downvote.  So I was wondering if the downvote record is visible only to me?  If so, is this done to protect downvoters from retaliation?


Is there a straightforward step-by-step instruction to replace Ubuntu OS with Google OS on a BQ Aquaris M10 HD tablet.  I know nothing about computer code and nothing can be assumed. These instructions need to be precise. I.e. do I need another computer to perform this operation If so, what kind? If it can be done entirely on the tablet, then exactly how is this done?


Make beamer center only table of both table and flowchart

I am trying to center only a table in a slide where there is a table and a forest flowchart. I have made a similar question  but don't know why is not working on this slide. Below I provide an image of this problem and then a minimal working example.    Here is a MWE:  \documentclass[aspectratio=169, hyperref={pdfpagelabels=false}]{beamer} %\documentclass[handout, hyperref={pdfpagelabels=false}]{beamer} \usetheme{Madrid}  \let\Tiny=\tiny \usepackage{multimedia} \usepackage{marvosym} %\usepackage[backend=bibtex,style=authoryear]{biblatex} \usecolortheme{whale}  \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{amssymb,amsmath,amsthm} \usepackage[spanish,es-tabla]{babel} \usefonttheme{professionalfonts}   \usenavigationsymbolstemplate{}  \setbeamertemplate{footline}[frame number] \setbeamertemplate{frametitle}[default][center] \setbeamersize{text margin left=2em,text margin right=2em}  \addtolength{\columnsep}{2cm}  \usepackage{ragged2e} \usepackage{forest} \usepackage{float} %\setbeamercovered{transparent} \usepackage[flushleft]{threeparttable} \floatstyle{plaintop} \usepackage{url} \usepackage{booktabs} \begin{document} \begin{frame}[shrink=15]{Resultados - Método de solvatación} \begin{itemize} \item Here some text... \end{itemize}  \vspace{0cm}\mbox{}\hfill\scalebox{0.50}{ \begin{forest}   for tree={     rounded corners, draw, align=center, top color=white, bottom color=blue!30,     edge+=->,     l sep'+=10pt,   },     [Solvatación      [Explícito+Implícito        [SS/COSMO, bottom color=green!30]%want this block green        [Packmol/COSMO, bottom color=gray!30]      ] %     [Implícito %       [COSMO] %     ]    ]  \end{forest} }\hspace{-4cm} \vspace{-0.5cm}\centering{ \begin{threeparttable} \caption{Convergence RM1 - DHAP} \begin{tabular}{ccccc}\toprule nºconf & $\Delta G^\circ_{\text{f(SS)}}$ & $\Delta G^\circ_{\text{f(Packmol)}}$ & $\sigma_{\text{SS}}$ & $\sigma_{\text{Packmol}}$ \\  \midrule 5 & -1756.3 & -1758.4 & 1.2 & 3.8 \\   10 & -1754.6 & -1760.8 & 2.9 & 1.3 \\   15 & -1755.7 & -1761.3 & 1.9 & 0.9 \\   20 & -1757.2 & -1761.6 & 0.3 & 0.5 \\   30 & -1757.2 & -1764.2 & 0.3 & -2.0 \\   50 & -1757.5 & -1762.1 & - & - \\  \textbf{MAE} &  &  & 1.3 & 1.7 \\ \bottomrule \end{tabular} \begin{tablenotes} \footnotesize \item {Here some text as a note..} \end{tablenotes} \end{threeparttable}} \centerline{ And short a conclusion like this...} \end{frame} \end{document}   Would you help me please?


Show that, for every real number a, the set {$x ∈ S | f(x) ≤ a$} is a closed subset of $\mathbb R^d$

Suppose that $S$ is a closed subset of $\mathbb R^d$ and that $f$ is a continuous real-valued function with domain $S$. Show that, for every real number $a$, the set {$x ∈ S | f(x) ≤ a$} is a closed subset of $\mathbb R^d$    I don't know how to start this. Do we use the fact that If $S$ is closed and bounded every sequence in $S$ has a subsequence that converges to a point in $S$?


Prove that if $3\mid a^2+b^2$ then $3\mid a$ and $3\mid b$.

For elements $a$ and $b$ in the ring $\Bbb{Z}$ prove that if $3\mid a^2+b^2$ then $3\mid a$ and $3\mid b$.  I tried proving it but I just don't manage to. Maybe I am missing some basic claims in the number Theory?  I would appreciate hints and, generally, your help.  I am sorry, there was another data I was given, I was fixed and resent to me.


I am not a high rep user nor active on Meta SE yet I worried that SE might disappear forever.  Can I backup a certain site?


Javascript mixin for objects whose properties are objects ambiguity

Here is a user-defined mixin for shallow cloning of objects:      function mixin(receiver, supplier) {       Object.keys(supplier).forEach(function(key) {          receiver[key] = supplier[key];       });        return receiver;     }     var supplier = {         a:{b:10}     };     var receiver = mixin({},supplier);   and according to my understanding assigning one object to other makes them equal since they have reference to same object literal and when one object changes its property it reflects on the other object too but the below tests puzzled me:      receiver.a === supplier.a //true     receiver.a = {b:20} //but     supplier.a //still {b:10} I expected {b:20}   What am I doing wrong here?? P.S I know about ES6 Object.assign() but this mixin is created just for my understanding.


What is the command to truncate a SQL Server log file?

I need to empty an LDF file before sending to a colleague.  How do I force SQL Server to truncate the log?


I have fitted a glm to my data set and used to the Durbin-Watson test to check model fit. I have obtained the result. How can i interprete it?  lag    Autocorrelation     D-W Statistic    p-value     1       0.7750748     0.4466024       0   Alternative hypothesis: rho != 0


Is leaving airport at a stop before the final destination illegal?

There are tricks such as  or  which involve booking a ticket composed of several connecting flights, then leaving the airport at a stop, possibly even "hopping off" a plane (intermediate landing). Rationale: Sometimes these tickets are cheaper than a ticket to one of the stops. So one adds an additional leg and discards it.  Some people say that when using such tricks, one enters a legal gray area. But I wonder:  Could leaving the airport at a stop really be illegal, i.e. violating an airline's or a travel agency's terms?  Also there are suggestions that one should not request an upgrade, because then the trick may be discovered by the airline. Here I wonder:  How can they know that one will throw away the last leg?


Prove X is banach iff $S(0,1)$ is complete.

Let $X$ a normed space. Let $S(0,1)=\{x\in X: ||x||=1\}$ Prove that $X$ is banach iff $S(0,1)$ is complete.  My attempt: $(\implies)$ Note $S(0,1)\subset X$ and we have $X$ is banach space.  Let $\{x_n\}$ a cauchy sequence in $S(0,1)$. We need prove that $\{x_n\}$ converge.  As $\{x_n\}$ is cauchy then exists $N$ such that if $n,m>N$ then $||x_n-x_m||<\epsilon$  Here i'm stuck.  $(<-)$  Let $\{x_n\}$ a cauchy sequence in $X$. Note for $n,m>N$ we have $||x_n-x_m||<\epsilon$.


Why can't a union of two intervals be the maximum existence interval of a solution?

Assume the IVP $$ x'=x^2, \quad x(0)=1 $$ By separating the variables and using the initial condition $$ x(t)=(1-t)^{-1} $$ Then, my book states that since $x_0=1>0$ then the solution can only be extended to the left with maximum existence interval $\, I=(-\infty,1)$.   My question is, since the solution $x(t)$ we found is defined for every $t\neq1$, why isn't the maximum interval of its existence $I^*=(-\infty,1)\cup(1,+\infty)$? Why does it depend on the sign of $x_0$?


Does shield retroactively change the result of an attack?

Shield spell Casting time line says (PHB, p. 275):     1 reaction, which you take when you are hit by an attack or targeted by the magic missile spell.   (bold highlight by me)  PHB, p. 194, 1st paragraph under "Attack Rolls" say:     To make an attack roll, roll a d20 and add the appropriate modifiers. If the total of the roll plus modifiers equals or exceeds the target's Armor Class (AC), the attack hits.   So, disregarding the magic missile spell case, the trigger for the Shield is the fact of hit, i.e. attack roll was made and it was determined that the target was hit. What would be the point of casting the Shield spell at this point if attack is already resolved?  Spell effect description says:     An invisible barrier of magical force appears and   protects you. Until the start of your next turn, you have a   +5 bonus to AC, including against the triggering attack,   and you take no damage from magic missile.   (again, bold highlight is mine)  The description seem to imply that it retroactively changes the outcome of the attack roll, otherwise the bolded text does not make any sense; but on the other hand it does not spell it out explicitly and it specifically has different wording for being hit by an attack vs. being targeted by magic missile (if the intention was to retroactively make attack miss, the wording could have used "targeted" for both cases; and PHB, p.194 explicitly mentions picking a target for attack, so targeting is a well-defined step).  Is there something that supports retroactive outcome change?


How do I change turret targeting parameters?

I remember in Fallout 3 and New Vegas that you could hack terminals controlling turrets to change a turret's targeting parameters (i.e. shoot your enemies and not you) but it seems that they've changed how things work in Fallout 4. I can run System Diagnostics and turn turrets off, but I don't know how to change the turret targets. I imagine it has something to do with the admin setting, but I don't know how to change that either.


How can I remove weird Â characters from my output without needing to edit hundreds of rows in MySQL.  Data is being read from a MySQL database and outputted to the browser via HTML.


Expressing Express $\lim_{n\to∞} \left(\frac1{n+1} + \frac1{n+2} + ... +\frac1{n+n}\right)$ using Riemann definite integration

Express $\lim_{n\to∞} \left(\frac{1}{n+1} + \frac{1}{n+2} + ... +\frac{1}{n+n}\right)$ as a Riemann integral.   I was able to transform it to $\lim_{n\to ∞}\sum\limits_{r=1}^n \frac1{n+r}$.  I don't know how to go about it from here.


Permalink rewrite with custom post type and custom taxonomy

I think thats a quick one:  I've got:   Custom post type: Food  Custom taxonomy (Registered to Food): Fruits Terms in Fruits: Apple, Orange, Cherry   If I type in example.com/food?fruits=Apple,Cherry, I get all posts in Fruits with the terms Apple and Cherry, thats great!  But I would like to type in example.com/food/fruits/Apple,Cherry or example.com/food/Apple,Cherry to get the same result.  I´ve tried different permalink and rewrite plugins related to custom posts but nothing helped.  Thank you,  David


Best way to get last identity inserted in a table

Which one is the best option to get the identity value I just generated via an insert? What is the impact of these statements in terms of performance?   SCOPE_IDENTITY()  Aggregate function MAX() SELECT TOP 1 IdentityColumn FROM TableName ORDER BY IdentityColumn DESC


Phone storage upgrade from 8gig to 16gig

How do I upgrade a phone with internal storage 8gigabytes to 16gigabytes


How to search for curly quotes on an StackExchange site?

Assume that I want to compare the relative usage/popularity of “ vs " on an SE site. I expect ELL and ELU to be curly-dominant, StackOverflow to be straight-dominant, but I am not so sure about the other sites, especially the science sites.  I can easily search for the . But, every time I type type the smart quote and press Enter, the search string is replaced by "“" and the search returns  (even when I know of posts on that site which have that curly quote in them). For example  on Chem.SE results zero results, yet there are several posts like , which use the curly quotes.  Is this the expected result? Why is the search not working correctly here?


I know that if a quadratic equation has roots s and t, you can factor it as (x-s)*(x-t) and I used that property countless times, but I have never quite understood why that should be. Any clarification and/or proof of this would be appreciated.  I suspect that st = c/a. Is there any way how to see this?


Started about 2 weeks ago with 3D modeling and just finished creating this spartan styled helmet for my characters in Unity. When imported and looking at the face of the helmet, you can see the sky from the backside of the helmet, making the helmet look like it has a hole on the backside. I took pictures of both to show there is no hole on the backside and to show the sky coming through the mask. If any additional information is needed to help answer the question, let me know.


In JavaScript, why does this  ['10','10','10','10','10'].map(parseInt)   Results in this?  (5) [10, NaN, 2, 3, 4]


Increasing, continuous function implies connectivity and viceversa.

I am having difficulties showing that this is true. How would you prove this statement?  Given that the function $h: \mathbb{R}\rightarrow\mathbb{R}$ is increasing. Show that $h$ is continuous if and only if  $h(\mathbb{R})$ is connected.


My DELETE method doesn't work from a Submit Form

Im trying to get a DELETE request working but it concat's to this: "" it doesnt go trough my app.js listener I have a console log. This is my code. (Oh and Im trying to get it to work with no ajax.  This is the HTML(with ejs):  <form method="DELETE" action="/users/delete">     <input type="hidden" value="<%= users[i]._id %>" name="userid">     <input type="submit" value="Submit"> </form>   And this is the Listener:    app.delete('/users/delete',function (req, res) {     console.log(req); })  What I do know that the ejs function works as you can see its being passed in the url and Ive tried printing it inside the html.


Can anyone give me a counterexample to this statement?

Statement:  Let $n$ and $m$ be two irrational numbers. Then $n^m$ is always irrational.  I think this statement is correct, otherwise can someone give me a counterexample?  Thanks!


Is there a countable transitive model satisfying the same set of first-order sentences as $V$?

This is probably a pretty simple question, but I'm tying myself in knots over it.  We're all familiar with the Reflection Theorem, Lowenheim-Skolem Theorem, and Mostowski Collapse Lemma for getting countable transitive models of finite fragments of ZFC. You take a finite fragment $\Gamma$, use the reflection theorem to get that $\Gamma$ holds in some $V_\kappa$, Skolemise over $V_\kappa$, and then Collapse to a ctm.  My question. Is there (or could there be) a countable transitive model satisfying the same first-order truths as $V$? Obviously, by Tarski, such a countable transitive model is not first-order definable.  A possible route:  Suppose full second-order reflection is true of $V$. Let $A$ be a second-order parameter that contains a witness for every parameter-free sentence of first-order $ZFC$ true in $V$. Then, just reflect the sentence $x \in A$, Skolemise, and Collapse as normal (I feel like I might be pulling a fast-one here).


I am confused about the hierarchy of settings   1) I have a profile A and it has a read only access. I have a permission set specific to an user and the permission set grants the user access to edit the opportunities in the system.  2) The Org wide default is private and the role says the user can view all data.  When I login as the user with the permission set that grants edit access, I see the edit button but when I edit I get " Insufficient Access"  Is there any setting that can override the permission set/is it because of the OWD I am being thrown off ?  Is there any way to find out why the "Insufficient privilege " shows up?


How are people who descend from same person related?

I am a descendant of President John Adams through his daughter,  Rebecca. My children's father is a descendant of John Adams through his son, John Quincy.  How are we related?  Are we cousins?  With a number of times removed?  I did not know my ex-spouse was related to me when we married in 1984.  Even though many generations have passed, I would not have knowingly married a distant cousin.


Why do the big nuts always remain at top? The Brazil-nut Effect

Most of the time when I mixed different nuts in a bowl, I observed that the big Brazil nuts were always on top while the small peanuts settled near the base. No matter how you take it, if the big nuts are put at the bottom and then the small nuts are poured, then also after some time the big ones will come to the top. Will not the gravity attract those big nuts more and eventually will they not remain at the base? But it doesn't happen!   I googled it and found the term Brazil-nut Effect but couldn't find any proper explanation. What is the physical explanation for this effect?


How did I get the "Unachievable" achievement?

I've just played through Stanley Parable for a few hours and have got all of the different endings (including all variations of the easter eggs), besides the "disco" one.  After quitting the game, I noticed that I got the "Unachievable" achievement. Looking at the time, I think that I got it around the time I got the "broken narrative" ending, but I'm not entirely sure.  I've looked up how to get the achievement and most guides involve adding key bindings and doing it through there - I definitely haven't done that. The only things I've done in the console are sv_cheats 1 and bark.    I am not looking for how to get the achievement, my question is that I have got the achievement and don't know how I did!


Weird sample variance when creating a lognromal sample with pre-defined mean and variance

I have been working with lognormal distributions as a proposal distribution for some MCMC routines which require the proposal distribution to have some pre-defined sample mean and variance, $m$ and $v$, respectively. Considering that I'm using scipy.stat.lognorm to generate a sample from the proposal distribution, I have to define $\mu$ and $\sigma^2$, parameters of the underlying normal distribution.   I've determined $\mu$ and $\sigma^2$ using the relation: \begin{equation} \mu=\ln\left(\frac{m}{\sqrt{1+\frac{v}{m^2}}}\right),  \qquad \sigma^2=\ln\left(1+\frac{v}{m^2}\right) \end{equation}  This have worked fine when $m \geq 1$, however when $m < 1$ the variance of the generated sample becomes smaller than it was supposed to be ($v$) and I am not sure why.  As an example, running the code bellow  def get_underlying_normal_params(m, v):     m2 = m * m     nrm_mean = np.log(m2 / np.sqrt(v + m2))     nrm_var = np.log((v + m2) / m2)     return nrm_mean, nrm_var   lognrm_mean = 1e-5 lognrm_var = 10 norm_mean, norm_var = get_underlying_normal_params(lognrm_mean, \         lognrm_var) sample = [lognorm.rvs(scale=np.exp(norm_mean), s=np.sqrt(norm_var)) \         for _ in range(50000)] print("Sample mean: ", statistics.mean(sample)) print("Sample variance: ", statistics.variance(sample))   the produced output is:  Sample mean:  1.3404377964314877e-06 Sample variance:  5.009857166696648e-09   We can see then, that the created sample has variance ~5e-9, far from the desired variance, 10.  If however, I run the same code setting lognrm_mean = 1, the output is:  Sample mean:  1.0077730236251317 Sample variance:  9.250922743416222   And now the sample variance is actually close to the desired variance.  Why was I able to pre-determine the variance of the sample on the second case but not on the first case? Am I doing something conceptually wrong?  Edit explaining why this is not a duplicate of : in my question I ask if there is something wrong in the procedure I used to create a lognormal with a pre-determined sample mean and variance. There could be a conceptual problem that I am missing or even a procedural problem, concerning for instance floating point erors; I am specifically interested in the behaviour of the sample variance. The other question asks the relation between parameters of a lognormal distribution (associated to an underlying normal distribution) and its mean and variance. Of course this relates to this question, however that is not the question I am asking and, moreover, I have given "formulas" for this relation in my question.


Given $p(x)$ is a polynomial with integer coefficients and that $p(a)=1$ for some integer $a$ prove that $p(x)$ has no more than two integral roots.  I've attempted a proof by contradiction assuming $p(x)$ has three or more roots, but haven't gotten anywhere on this. Help would be appreciated!


Number of real solutions $2\cos(\frac{x^2+x}{2})=2^x+2^{-x} $

The number of real solutions of $2\cos(\frac{x^2+x}{2})=2^x+2^{-x} $  is   (1) 0  (2) 1   (3) 2  (4) infinitely many .  My work :   $$ 1\geq \cos\left(\frac{x^2+x}{2}\right)=\frac{2^x+2^{-x} }{2}\geq 1  \qquad \text{by (AM-GM).} $$  So $\frac{x^2+x}{2}=2n\pi$ for all $n\in \mathbb{Z}$ . Now discriminant $=1+2n\pi$  is always positive for $n\geq0$  . But the equation is a quadratic so it has only two solution . Hence the answer must be 2 .  PS: I'm aware that the this problem is already on the site but i posted as there were no complete solution .


Stuck on this integration $\int_0 ^\infty \frac{1}{1+x^2} \cos(kx) dx =\frac{\pi}{2}e^{-k}$

I'm not sure how to show this  $$\int_0 ^\infty \frac{1}{1+x^2} \cos(kx) \ \mathrm dx =\frac{\pi}{2}e^{-k}$$  I tried by parts but I'm not getting anywhere, I'd really appreciate the help


If I used an everyday 9v alkaline battery to power a 6v DC motor, would it work?

I am totally new to electronics and don't know much but am trying to create a project that uses a 29rpm 6v DC motor. I was wondering if I were to use a higher voltage battery ( a 9v battery) would it be able to power the lower voltage motor?


Does there exist a nowhere dense subset $X$ of a metric space such that complement of $X$ is not dense?   I know $X$ cannot be closed. Any ideas for general case?


Drawing a blank here. I'm trying to recreate Jack Sparrow's famous bandana; a red base colour with a blue floral pattern. I've started off with a red, diffuse base on my bandana mesh and I've acquired a decent image of a vector floral pattern with an alpha background.  My problem is: how do I then add this floral pattern on the surface of my red bandana? Can I not stack image textures in the same material? The floral pattern is a png image, and its alpha channel is apparent when I use the alpha textured material method. However, I don't want my bandana to be transparent.   How do I add the floral pattern to the opaque base material while retaining the image's transparency?


$E(X|X)=X$ Conditional expectation of a variable with itself

I’m trying to find a post that asked why/what $E(X|X)=X$ and further, in the answers, the bottom answer explained why $E(f(X)|X)=f(X)$, but I can’t find it. It’s weird because I’m usually good at remembering what I google. Does anyone have the post I’m talking about?


I am trying to remove a package in windows 10 but receive the following error. I have spent some time searching on the internet but none of them have the same error as me. Please advise.  PS C:\WINDOWS\system32> remove-appxpackage Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8wekyb3d8bbwe remove-appxpackage : Deployment failed with HRESULT: 0x80073CFA, Removal failed. Please contact your software vendor. (Exception from HRESULT: 0x80073CFA) error 0x0: Reading manifest from location: AppxManifest.xml failed with error: The operation completed successfully. . NOTE: For additional information, look for [ActivityId] 1af2746e-664b-0006-4fcc-f21a4b66d501 in the Event Log or use the command line Get-AppPackageLog -ActivityID 1af2746e-664b-0006-4fcc-f21a4b66d501 At line:1 char:1 + remove-appxpackage Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8weky ... + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : WriteError: (Microsoft.Dayto...__8wekyb3d8bbwe:String) [Remove-AppxPackage], IOException     + FullyQualifiedErrorId : DeploymentError,Microsoft.Windows.Appx.PackageManager.Commands.RemoveAppxPackageCommand   This is not a duplicate of . The error message is different and my IsInbox already has a default value of 0.  I requested the log and received this. I still have no idea what is going on.  PS C:\WINDOWS\system32> Get-AppPackageLog -ActivityID 03c48bb9-6706-0007-559d-c4030667d501  Time                      ID           Message ----                      --           ------- 9/9/2019 8:17:11 PM       603          Started deployment Remove operation on a package with main parameter                                        Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8wekyb3d8bbwe and Options 0 and 0.                                        See http://go.microsoft.com/fwlink/?LinkId=235160 for help diagnosing app                                        deployment issues. 9/9/2019 8:17:11 PM       10002        Creating Resiliency File C:\ProgramData\Microsoft\Windows\AppRepository\3dbed2a1                                        -d201-495b-b6e4-fcbcd04aade9_S-1-5-21-3890243703-3931977587-3464021798-1001_2.rs                                        lc for Remove Operation on Package                                        Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8wekyb3d8bbwe. 9/9/2019 8:17:11 PM       607          Deployment Remove operation on package                                        Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8wekyb3d8bbwe has been de-queued                                        and is running for user SID S-1-5-21-3890243703-3931977587-3464021798-1001. 9/9/2019 8:17:11 PM       402          error 0x0: Reading manifest from location: AppxManifest.xml failed with error:                                        The operation completed successfully.                                        . 9/9/2019 8:17:11 PM       605          The last successful state reached was BundleProcessed. Failure occurred before                                        reaching the next state Indexed. hr: 0x80070490 9/9/2019 8:17:11 PM       401          Deployment DeStage operation with target volume C: on Package                                        Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8wekyb3d8bbwe from:   failed with                                        error 0x80070490. See http://go.microsoft.com/fwlink/?LinkId=235160 for help                                        diagnosing app deployment issues. 9/9/2019 8:17:11 PM       404          AppX Deployment operation failed for package                                        Microsoft.Dayton.f074ae31c9_1.3160.34.2_x64__8wekyb3d8bbwe with error                                        0x80073CFA. The specific error text for this failure is: error 0x0: Reading                                        manifest from location: AppxManifest.xml failed with error: The operation                                        completed successfully.


Is it correct to assume that Property in Java it is simple getter and setter?


Let $x$ and $y$ be random variables with the following joint density function: $f(x,y) = e^{-x}$ for $0<x< \infty$, and $0<y<1$  If $z= x+2y$, what is the joint density function of $x$ and $z$.  Can we first find the PDF of x and then z and then multiply the two. With that approach the answer doesn’t match


How to conditionally create a hyperlink based on value of a cell

ColA                  Col B              ColC Project A            A.pdf               A.pdf Project B                                No Link   I have a list of project records. One column (e.g., B) may have a reference to a pdf file. If I create a formula   =if(isblank(B2),"No Link",hyperlink(folderURL + B2),B2)   What I want is to place a hyperlink on only those rows where column B contains a pdf reference, and insert text "No Link". I get the proper text values, but in all rows have the hyperlnk default appearance and behavior -- Excel seems to be creating "phantom links" out of the "No Link" cells.     Clicking on the "No Link" value in Col C activates an attempt to open the file listed in Col B, which returns a No file found error.


Show that recurrence relation $x_{n+1} = {1\over 2}\left(x_n + {b^2 \over x_n}\right)$ where $x_1 = a >0$ is bounded.

Given the following recurrence relation:   $$ \begin{cases} x_{n+1} = {1\over 2}\left(x_n + {b^2\over x_n}\right) \\ x_1 = a > 0 \\ n\in \mathbb N \end{cases} $$   Show that $x_n$ is a bounded sequence.   This question follows after  so perhaps it may help me solve the linked question.  No constraints on $b$ are given in the problem statement. I've started with $x_n$:  $$ x_{n+1} = {1\over 2}\left(x_n + {b^2\over x_n}\right) \\ x_n = {1\over 2}\left(x_{n-1} + {b^2\over x_{n-1}}\right) \implies \\ x_{n+1} = {1\over 2}\left({1\over 2}\left(x_{n-1} + {b^2\over x_{n-1}}\right) + {b^2\over x_n}\right) = \\ = {1\over 2}\left({1\over 2}\left({1\over 2}\left(x_{n-2} + {b^2\over x_{-2}n}\right) + {b^2\over x_{n-1}}\right) + {b^2\over x_n}\right) = \\ \dots\\ \frac{b^2}{2^1x_n} + \frac{b^2}{2^2x_{n-1}} + \frac{b^2}{2^3x_{n-2}} + \dots + \frac{b^2}{2^nx_{1}} + {a \over 2^n} = \\ = {a \over 2^n} + \sum_{k=1}^n \frac{b^2}{2^{n-k+1}x_k} $$  So i got:  $$ x_{n+1} = {a \over 2^n} + \sum_{k=1}^n \frac{b^2}{2^{n-k+1}x_k} $$  This seems to be correct while i've tested several first terms and they match the initial recurrence. Now I'm wondering how is this even bounded? BTW W|A suggests that:  $$ x_n = b \coth\left(2^{n - 1} \coth^{-1}{a\over b}\right) $$  Not sure where it's derived from. How do I show this sequence is bounded using precalculus Maths?


Is using L'Hospital's Rule to prove $\lim \limits_{x \to 0} \sin{x}/x$ circular?

If  $\frac{d(\sin{x})}{dx}= \cos{x}$  is proven using the limit $\lim \limits_{x \to 0}\frac{\sin{x}}{x}=1$ (as it is in most textbooks), would it be circular to then use $\frac{d(\sin{x})}{dx}= {\cos{x}}$ and L'Hospital to prove the limit $\lim \limits_{x \to 0}\frac{\sin{x}}{x}=1$ (because limit $\lim \limits_{x \to 0}\frac{\sin{x}}{x}= \frac{\cos{0}}{1})$ later in the same textbook?


How can I check an array for an object before its been added?

Problem is, I make an empty array and it stays empty until a user is on my page and inputs their "username" and their "ID" and clicks a button.   I have to check the array for duplicates so I want my code to check the array, if nothing with the same name exists then add it into the array. Here is my code that does not work  var myArray = [];   function arrayChecker(inputName, inputID) {     for (var key in myArray) {         if (myArray.hasOwnProperty(key)) {             console.log(key, myArray[key]);         } else {             myArray.push({"name": inputName, "id": inputID});                    }     }   }   This does not work however. Any ideas?


print(..., end=' ') with immediate output

I need a piece of Python code that loads (stresses?) CPU for a short moment. I would also like to get some output like counter printed during stressing CPU. Seems simple enough: N=32  def fib(n):     if n < 2:         return 1     else:         return fib(n-1) + fib(n-2)   def main(num):     for i in range(1, num+1):         fib(N)         print(i, end=' ')  if __name__ == '__main__':     main(10)  However, when I use print(i, end=' '), it does not output counter as it executes, it only outputs 1 2 3 4 5 6 7 8 9 10 once it completes. If I use regular print (print(i)) it prints the counter as it goes. First of all, I want to know why this weird effect takes place, and second, how to make print with end behave in this regard like print without end keyword.


How to to play youtube Video in VLC Player. How this possible. we have windows 7 and VLC media player 2.1.3....? like. this video play into VLC


What is the cheapest way to run AIX 6-7 at home? Using an emulator or is there any low-cost hardware that can run AIX6 or AIX7?  Purpose: practicing VIO/LPAR/HMC/etc..


Protagonist in mist/fog in a featureless place

Looking for title / author. A thin book I read in the early '60s. Maybe 100-125 pages.  Protagonist alone in fog/mist in a featureless place. As the book progresses more people show up and are as confused about how they got there as the protagonist. People spend time trying to explore this "non-place". Near the end of the book an explanation is given about some "field", fixed in space which travels over the surface of the earth as the planet rotates. If you're at the focus, you're transported to this non-place.  Thats about all I can remember. I'd love to find this book again and re-read it. It stuck in my mind all these years.


I have created below table using TOAD.   CREATE TABLE TEM (     No number );   But i got below error when try to insert many values in "No" column.  My insert statement:   INSERT INTO TEM1k (No) VALUES (8882323,454343);   Error Msg:      ORA-00913: too many values   Appreciate your support to fix this issue.   Thanks,


Show that $f_n \to f$ in $L^2(d\mu)$ if $f_n \to f$ a.e., $f_n \ge 0$, $f_n \in L^2(d\mu), f \in L^2(d\mu)$

Consider $f_n \to f$ a.e., $f_n \ge 0$, $f_n \in L^2(d\mu), f \in L^2(d\mu)$ and $\int |f_n|^2 \, d\mu \mathop{\longrightarrow}\limits_{n \to \infty} \int |f|^2 \, d\mu$. Find an elementary argument to show that $f_n \to f$ in $L^2(d\mu)$.  We need to show that: \begin{align*}   \lim\limits_{n \to \infty} \lVert f_n - f \rVert_2 &= 0 \\   \lim\limits_{n \to \infty} \left(\lVert f_n - f \rVert_2\right)^2 &= 0 \\ \end{align*} Starting with: \begin{align*}   \lim\limits_{n \to \infty} \left(\lVert f_n - f \rVert_2\right)^2 &= \lim\limits_{n \to \infty} \int (f_n - f)^2 \, d\mu \\   &= \lim\limits_{n \to \infty} \int (f_n^2 + f^2 - 2 f f_n) \, d\mu \\   &= \lim\limits_{n \to \infty} \int f_n^2 + \int f^2 - 2 \lim\limits_{n \to \infty} \int f f_n \, d\mu \\ \end{align*} Since $f_n \to f$ in $L^2(d\mu)$, we can simplify: \begin{align*}   &= 2 \int f^2 - 2 \lim\limits_{n \to \infty} \int f f_n \, d\mu \\ \end{align*} If $f_n \nearrow f$ we could use the monotone convergence theorem to conclude this proof. But we don't have that. I'm not sure how to conclude this.


Applying filters to individual messages in Gmail (not entire conversation)

I'm using a system which sends out some useless emails and some very important emails. However, they share the same title, so they're grouped into the same conversation by Gmail. I'm trying to apply a filter that adds a "Useless" label to the useless emails. However, this adds the label to the entire conversation. If there are useful and useless messages in the same conversation, how do I make sure that the useless ones don't show up in my inbox?