A coin is tossed three times: The probability of zero heads is 1/8 and the probability of zero tails is 1/8.  And my question is: What is the probability that all three tosses result in the same outcome?   So, if P(zero heads)= 1/8 , then that should be the same of p(all tails)?  If so, we could use the Addition Rule which is $P(A \cup B) = P(A) + P(B)$  where A and B are disjoint events, i.e. $A \cap B = \emptyset$, A is the event of tossing all heads and B is the event of tossing all tails.  I'm not sure how to continue after that... would the complement be used?


Show that the equation $x^2+y^2+z^2=2xyz$ has no integer solutions except $x=y=z=0$ using modular arithmetic

(a) Using modular arithmetic Show that the equation  $$x^2+y^2+z^2=2xyz$$ has no integer solutions except $x=y=z=0$  (b) Using the results in part (a), show that the equation $$x^3+2y^3+4z^3=0$$ has no integer solutions except $x=y=z=0$  What i tried  For part (a),   At least one of x,y,z is odd. Can it be even? Reduce mod 4  $(even)^2=0 (mod 4)$ $(odd)^2=1 (mod 4)$  implies that LHS = 2 (mod 4)  all 3 are even ie, $x=2x_{1}$, $y=2y_{1}$, $z=2z_{1}$ implies that $$4x_{1}^2+4y_{1}^2+4z_{1}^2$$  (b) I have to somehow reduce the equation of part(b) to something similar to that of part(a).  Equation of part (b)                          $$x^3+2y^3+4z^3=0$$  removing the $x,y,z$ term, we have                           $$x^2+2y^2+4z^2=0$$  and since $x^2$ is even, $x$ is even we have $x=2a$, doing the same for $y$, $y=2b$ and $z$, $z=2c$ we have,the equation  $$(2a)^2+2*(2b)^2+4*(2c)^2=0$$, However im unsure of how to continue from here, could anyone help me with this question, especially part (b). Thanks


Fill a field based on the selection from a domain of another field

I have 700 Unique values “Communities” and each one of this 700 unique communities has a unique reference. For example the community “Abc” has a reference “A001”, Now I have two fields in my attribute table the first one is CommunityName and the second is REF_Number this two fields should be filled. The question now is there any method that allow me fill the field “REF_Number” based on my section form the domain of the communityName field to limit the errors and to avoid filling the data two times. For example: If I select the community Abc form the domain list then the value of the field REF_Number should be updated automatically to A001.


How is money held in escrow for a home purchase from a IRA treated by the IRS?

I'm in the process of purchasing a home and I need to put 5% of the value down to be held in escrow until the deal closes. This money can then either be refunded back to myself or be rolled into the down-payment. I know that as a first time home buyer I can withdraw $10,000 without the 10% penalty, but the money has to be used within 180 days. In the event that the deal takes longer than expected (around 55 days from date of offer acceptance) or the deal falls through, how does the IRS treat the $10,000 that is still outstanding? Would it have to be immediately redeposited or could it be held in escrow until another deal goes through?


Interface vs class with pure virtual methods

I wanted to write shell extensions for windows in plain C++, but then I got confused by the keyword interface. In many articles I read that I can create interfaces in C++ by writing classes containing only virtual methods without any code. For example:  class IIsThisAnInterface_QuestionMark {     virtual MyMethod (         int firstParameter,         double secondParameter) = 0;     virtual AnotherMethod (         wchar_t *firstParameter) = 0; }   But the author of  article defined interfaces by using the interface keyword. So my question is: How to correctly define interfaces in C++? (Becuase I grew up in C#'s world, I know interfaces as constructs specifying methods for classes that are implementing these interfaces.)


I was doing a quest for the companions. When I entered Jorrvaskr, Farkas pulled out his sword and began to talk to me. Every time I would try to leave the conversation he would just follow me and try to talk to me again. This lead to me paralyzing Farkas and running away.   By the time I got to the gates of Whiterun he had already gotten up, ran to me and started another conversation. I quickly made it to the gates and exited, he followed me through the gates but I whirlwind sprinted to Shadowmere then attempted to fast travel - which game me the "Can not fast travel when guards are pursuing you" message even though no guards were following me.   I knew Farkas wasn't far behind so I quickly jumped on a carriage and I traveled to the nearest hold which was Dawnstar. Now I can't leave Dawnstar because the same message appears. I have tried to pay off my debt to the Dawnstar guards but it didn't fix the problem. How can I resolve this issue?


How to send email from Gmail with sub-addressing tag?

I have subscribed to mailing lists using Gmail's .  The subscribed email address is of the format hikingfan+mailinglists@gmail.com and I can receive emails on the same address. But when I reply to an email it is sent without the sub-address tag i.e. hikingfan@gmail.com.  The sent message is being held until the list moderator can review it for approval since the list considers it as a post by a non-member to a members-only list.  Since hikingfan+mailinglists@gmail.com is already a member of the list, is there any way to send emails with the sub-addressing tag?


How to make Ubuntu show date AND time on Files screen?

Ubuntu 12.04 used to show date and time of files in directory in Files.  With 13.04, only date is shown (for files created before the current date).    How can I make date and time to show in Files on 13.04?  Thank you in advanced.


Smashed screen on Xperia Z3, need to download data without touch capabilities

My wife accidentally smashed the screen on her Sony Xperia Z3 and the touch screen is not useable. There are colors and lines but nothing else. All of the ports on the device work just fine. However, I cannot access the phone's files with my PC because USB connection settings are currently set to charge the phone. I need to do the Data Transfer setting but am unable because of the broken touch screen. I talked to Sony support and they were no help whatsoever.  Can someone please tell me if there is a workaround? I am a tech so I will understand what you are saying even if it is complicated. Thanks, Mark


Deletion votes not being recorded on user profile?

The votes tab on my user profile doesn't seem to be recording my delete votes, whether a post was deleted from Moderator Dashboard or from individual posts.  For instance, on my Super User profile, it indicates that the last deletion vote I had cast was on January 9th. Given the number of posts I delete, I know this is not true.  My latest post deletion was  done about an hour ago, but my profile hasn't recorded that vote, neither has it recorded many other delete votes.


I need to build a function that takes in 2 tuples, and pairs them to all the pairs possible.  for example i need to take to tuples:  first_tuple = (1, 2) second_tuple = (4, 5)   and the result need to be:  ((1, 4), (4, 1), (1, 5), (5, 1), (2, 4), (4, 2), (2, 5), (5, 2))


Add two 256-bit hexadecimal numbers in bash?

I need to add base 16 alphanumeric data using bash command. This works for numbers   total=$(( 55 + 60 ))    but not alphanumeric. Is there a simple bash command for adding alphanumeric data? I'm adding large alphanumeric data like this:   436389bdc34dd718c7959db8d6df16967f2b9895e515da45fb09136183a7a9e2  + 1f0c45bbe9bc71a862f0d9672d056d2d741719a2b2d46ea6b269931d0b57674f


I have a problem , i can't open synaptic >:(  root@dopeboy:~# synaptic No protocol specified ** (synaptic:6940): WARNING **: Could not open X display No protocol specified (synaptic:6940): Gtk-WARNING **: cannot open display: :1   I have try to Re-install it but is not working, any idea how to fix?! VPS Ubuntu 14.04 LTS.


Entropy and the principle of least action

Is there any link between the law of maximum entropy and the principle of least action. Is it possible to derive one from the other ?


I have a YAML File with following data and i want to Deserialize that into java Object.  connector:   provider: ABCD   nodes:    -  1.1.2.1   -  1.2.2.8   maxconnection: 1   minconnection: 1   1.First i created a class called Connector where i have defined all the variable like Provider, Nodes, maxconnections, Minconnections. 2.Then i created a class called group and call the Connector class. 3.then in the main function tried to load the yaml file and call it.  But i got Null pointer exception Error  #Connector Class public static class connector {              private String provider;              private String[]  nodes;              private int max_connections;              private int min_connections;               public String getprovider() {                 return provider;             }             public void setprovider(String provider) {                 this.provider = provider;             }            public String[] getnodes() {               return nodes;             }             public void setnodes( String[] nodes) {               this.nodes = nodes;             }                         public int getmax_connections() {               return max_connections;             }             public void setmax_connections(int max_connections) {               this.max_connections = max_connections;             }             public int getmin_connections() {               return min_connections;             }             public void setmin_connections(int min_connections) {               this.min_connections = min_connections;             }              @Override             public String toString() {                 return "connector: {provider: " + this.provider + ", nodes: " + this.nodes + ",max_connections: " + this.max_connections +",min_connections: " + this.min_connections +"}";             }   #Group class          public static class Group {             private ArrayList<connector> connector;              public ArrayList<connector> getconnector() {                 return connector;             }                         public void setconnector(ArrayList<connector> connector) {                 this.connector = connector;             }         }  #main Class  public static void main(String[] args) {              final URL resource = YamlConf.class.getResource("demo.yaml");             final Constructor peopleContructor = new Constructor(Group.class);             final TypeDescription peopleDescription = new TypeDescription(connector.class);             peopleDescription.putMapPropertyType("connector", connector.class, Object.class);             peopleContructor.addTypeDescription(peopleDescription);              final Yaml yaml = new Yaml(peopleContructor);             try {                 final Group group = (Group) yaml.load(resource.openStream());                 for (final connector connector : group.getconnector()) {                     System.out.println(connector);                 }              } catch (IOException e) {                 e.printStackTrace();             }         }


Is it a good time to replace my used car?

We have a  with 105,000 miles that we purchased in 2011.  We have made many repairs such as replacing the transmission, repairing the radiator, heating and AC system, thermostat, belt, rotors and brake pads, alternator, gaskets, and we are now facing an $800 repair for the fuel tank.  The average cost of repair has been about $1470 per year since the beginning of 2015 if I include the pending $800 cost to repair the fuel tank. The transmission disproportionately weighted the average since it cost $2000.  Since we have a good credit rating, at a cost of about $1470 per year for repairs for this car, does it make sense to get rid of this car and either buy or lease a new comparable car? I am asking about this from a cost perspective and ignoring any other advantages that a new car may offer.  We own the Impala in full: no payments.


How can I save a web page as single page PDF?

Web pages can be very long. When I save it as PDF, chrome splits it to multiple pages. Is there a way to create a single page PDF with custom page width/length?  I need it to be a PDF in order to insert as attachment in wiki pages I’m maintaining.


label array with image icons (null pointer error)

I've been trying for hours to be able to be able to give a label a picture if it has a blank image ('blank.jpg') and every time i'm coming up with either an out of bounds error or a null pointer error (currently). Can anyone help me out and check my code for the problem:  public class HomeController extends JFrame {    public HomeController()   {     JFrame main = new JFrame();     main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     main.setTitle("Smart Home Control Panel");             //PANEL CONTAINING THE PICTURES     JPanel labelPanel = new JPanel();      labelPanel.setLayout(new GridLayout(3,3));     labelPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));      ImageIcon blank = new ImageIcon("blank.jpg");     ImageIcon lamp = new ImageIcon("lamp.jpg");     ImageIcon clock = new ImageIcon("clock.jpg");     ImageIcon television = new ImageIcon("television.jpg");      JLabel pictures[]=new JLabel[9];     for (int i=0;i<=pictures.length; i++)     {         pictures[i].setBorder(BorderFactory.createLineBorder(Color.BLACK));         pictures[i].setIcon(blank);         labelPanel.add(pictures[i]);     }       main.add(labelPanel, BorderLayout.CENTER);     //----------------------------------------------------------       //PANEL CONTAINING BUTTONS     JPanel buttonPanel = new JPanel();      JButton but1 = new JButton("ADD APPLIANCE");     JButton but2 = new JButton("CLEAR SCREEN");     JButton but3 = new JButton("LOAD FILE");     JButton but4 = new JButton("SAVE FILE");      buttonPanel.add(but1);     buttonPanel.add(but2);     buttonPanel.add(but3);     buttonPanel.add(but4);       main.add(buttonPanel, BorderLayout.PAGE_END);     //-------------------------------------------      //EVENT HANDLER FOR BUTTONS     but1.addActionListener(new ActionListener()     {         public void actionPerformed(ActionEvent e)         {              Object[] options = {"Clock",                     "Lamp",                     "Television"};             int n = JOptionPane.showOptionDialog(main,             "Which type of appliance?  "             + "",             "",             JOptionPane.YES_NO_CANCEL_OPTION,             JOptionPane.QUESTION_MESSAGE,             null,             options,             options[2]);             if (n == JOptionPane.YES_OPTION)             {                 setAvailable(clock);             }           }           public void setAvailable(ImageIcon clock)          {             for (int i=0; i<=pictures.length; i++)             {                 if(pictures[i].getIcon().toString() == "blank.jpg")                 {                     pictures[i].setIcon(clock);                 }             }           }      }      //-------------------------  }       }


Entropy on interacting particles and objects

I am not seeing a lot of discussion on this top, which is why I am bring it up. Entropy is observed for non-interacting particles; No surprise there. But, for interacting particles or objects, entropy does not seem to always apply. For example, throw random piles of magnets together. Salt crystal forming cubes when water evaporates. Water molecules form snowflakes below subzero temperature. Chemical reactions in general and the infamous Miller–Urey experiment (). Please share your thought on this. Thank you.


Boyfriend tourist/student visa denied 3 times

My case has many issues. I am in a long-distance relationship with a man from South America. For 3 years he has been trying to enter the USA on his own and got denied 3 times a visa.  The first refusal was when he applied for his tourist visa. He waited a year and then applied to study English here in the US, they denied him again. He has done everything to prove he can return back to his country. The most recent refusal was section 214b. He wanted to do it on his own, so he applied for a student visa so he could study here in the USA and we can grow our relationship.  That’s impossible now because he’s been rejected 3 times. The first time, he applied to come for a vacation here in the USA. He put me as a family because in reality he's a distant cousin. They denied him the visa because he has family here. The next time, he applied for a student visa. The school itself in New York told him to tell immigration that he had no family here, but it was already on the record that he did say because of me.  The school offered him a chance to get a visa in the UK, so he left for a couple of months to the UK. When he came back to his home country, he decided to apply a year later again for a student visa. He was denied again even after proving ties. He has a family business and his uncle was going to pay for the whole trip.  He has no hope now and he believes that if we get married that visa will just be rejected too. He doesn’t want to do it based on marriage for fear of his past history. He wanted to try alone. Is there any way someone can offer me some advice?


How to prove $\lim \limits_{n\to\infty}(n+1)\int_{0}^{1}x^nf(x)dx=f(1)$

I need help to prove this in real analysis. I think it uses IMVT, but not sure how to do it.     Let $f(x)$ be a real valued continuous function on $[0,1]$. Show that   $$ \lim \limits_{n\to\infty}(n+1)\int_{0}^{1}x^nf(x)dx=f(1) $$


The square of every prime number can be expressed in a linear form.

While working on the Collatz conjecture, I've found that the square of every prime number $p$ (except 2 and 3)can be written in the form of $12k+1$.  $p^2=12k+1$.$(k\in\mathcal N)$  is this a new discovery ? or have been used earlier somewhere.


Geometric intuition for $\pi /4 = 1 - 1/3 + 1/5 - \cdots$?

Following reading this great post : , Vadim's answer reminded me of something an analysis professor had told me when I was an undergrad - that no one had ever given him a satisfactory intuitive explaination for why this series definition should be true (the implied assumption being that it is so simple, there should be some way to look at this to make it intuitive).  Now it follows simply from putting $x=1$ in the series expansion $$ \tan^{-1}(x) = x - \frac{x^3}{3} + \frac{x^5}{5} - \cdots $$  but I don't see anything geometrically intuitive about this formula either!


i want to install a 4800 watt construction heater in my garage that is already wired with a 60 amp subpanel.  It has lots of room for extra breakers in the sub panel so i plan to install a 30 amp breaker (the heater specs say it is 21 amps, so the 30 amp breaker appears correct)..  The heater will be plugged in 42 feet from the subpanel so i estimate it will take about 50 feet of wire.  WHAT TYPE OF ELECTRICAL WIRE DO I NEED FOR THIS?


How to package all faces of a font into one family file (Mac)

I've got a few fonts I've purchased over the past few years.  These are decent quality fonts with, on average, 8–15 different faces for the family.  The problem I have is each face is listed separately in various applications (Photoshop, Indesign, etc.) Rather than simply one item with a submenu for faces.  For example I have: (fig. A)   FontA Bold >            Regular FontA Bold Italic >            Regular FontA Italic >            Regular FontA Regular >            Regular   Rather than: (fig. B)   FontA >         Bold         Bold Italic         Italic         Regular   What tool on the Macintosh can combine these faces so they are all listed under the family name? As in the figure B, above.  I know there are a couple of high-end apps (Fontographer, FontLab). Are there any basic smaller apps to simply edit the font info without editing character and other tables? I don't want to edit the actual font data specifically, merely the titles and naming structure I believe.  How do I do this with the tool suggested, specific steps please?  Notes: Running Mac OS 10.7, but can boot to 10.6 or 10.8 if needed. I am not absolutely looking for freeware. If there's a paid app to do this, I'm fine with that. If someone wants to outline steps in FontLab or Fontographer, I'm all ears.  These are commercial .otf fonts.


What exactly are limits used for in real life applications?

I am currently taking a Survey of Calculus course and recently we started learning about these things called limits.  I know that they basically tell you what the "y" value of a function will be/be near, as "x" approaches a certain point, but I don't know what use this would be outside of finding "y" at certain points on a graph and derivatives of tangent lines (which becomes useless once you learn the "power rule.")  What exactly are limits, and what are some real life applications?  Are limits what Isaac Newton created to figure out where planets would be at certain points?


Which is the correct usage of "and" in American English in this example?

Scenario 1 A series of unfortunate events has led Makoto "Edamame" Edamura to adopt the life of crime—pickpocketing and scamming others for a living. However, after swindling a seemingly clueless tourist, Makoto discovers that he was the one tricked and, to make matters worse, the police are now after him. Scenario 2 A series of unfortunate events has led Makoto "Edamame" Edamura to adopt the life of crime—pickpocketing and scamming others for a living. However, after swindling a seemingly clueless tourist, Makoto discovers that he was the one tricked , and to make matters worse, the police are now after him. I beleive it is Scenario 2 because "and" is always a coordinating conjunction.


Windows 8 drive shows no space but no data is inside

So D drive shows 85% consumption where inside the drive sub folder sums up to only 20% of the space.    I have already checked for the hidden files. I also used windirstat too which showing few extra files inside D drive's $recycle.bin folder but when I actually access that folder it comes out to be empty.  Not sure which data is consuming space.    Attaching windirstat screen shot


Full circle with symbol like smiling mouth in notification bar

Does anybody know, what is this icon in the notification bar in the top left corner?    I saw it on screenshot, thats why I cant check it on my mobile phone.  Thanks.


Are all oscillatory motions periodic motions?

For example, if a pendulum system in the real world oscillates its amplitude and period will eventually decrease. Does that still count as a periodic motion? Since the motion doesn't have the same amplitude at equal time periods.


Does a C1 US transit visa allow entry and travel (tourist) in Mexico?

I am a South African passport holder and will be travelling to Mexico in May for 10 days. My flight is via a US airport, where I will be in transit for a few hours on the way to Mexico and then again when I return. I will not actually be visiting the US at all.  I understand that US tourist visa holders can enter Mexico as a tourist. I have 2 questions:   If I apply for a C1 US transit visa, can I still use this to enter Mexico? Or does only the B1/B2 US visa allow for entrance into Mexico? Once I get my US visa, do I have to separately apply for a Mexico tourist visa or can I just arrive in Mexico and show them my passport with the US visa in it – ie is this enough?


A Flag to close Questions from ongoing Contest

I am requesting for a new flag so that we can immediately flag questions in which people are asking for help on a problem from an ongoing contest, and if there is anything related to code or the algorithm in that question, it is deleted permanently from the view of others.  I am asking for this because I have seen a few questions, in which the OP was asking us to help fix their code on Stack Overflow. The Code they posted was from an ongoing contest on , and that would be considered cheating.  On codechef, we are told to not share anything from code, algorithm, or anything related to a problem from an ongoing contest, but since users are unable to ask their questions there, they come to Stack Overflow and ask it there.  Up till now, when I encounter questions like that, I flag them for moderator attention explaining the reason ( I don't have enough reputation to vote to close ).   I have not been a user on SO for long, but I have met a few questions like this already. This is one  . It's already deleted, but I think there should be a quick way to flag it so that it is brought to the notice of moderators quickly so that the code is not leaked. ( I don't want to increase the Work load on moderators, but something similar would be useful ).  So I request a new flag so that these questions can be flagged quickly to prevent the leaking of code and also make it easier, rather than having to type a good reason and wait for a moderator to accept it.  Please forgive me If this is a Duplicate as I could not find anything related to this on MSE yet.


80's-90's book with an inter-generational ship, society in despair, mythical creatures appear and kidnap kids for a quest

Read this book in the 80’s or 90’s. Sci-fi fantasy set aboard a generational ship, people despair because life has no meaning. Suddenly mythical creatures start appearing and some children are kidnapped into a quest with them. Parents watch via virtual reality and can help kids on the quest by sending clues.


$G/N\cong G/N'$ implies $N\cong N'$ for the normal subgroups?

We have normal subgroups $ N$ and $ N'$ of a group $ G $. Is the following statement correct?  $G/N\cong G/N'\Leftrightarrow N\cong N'$.  $\Leftarrow $ is trivial.  $\Rightarrow:$ I don't know how to start. Or should I search for counter examples?  I would be pleased, if someone could give a hint.


Getting QGIS 2.x python code to work in QGIS 3.x? object has no attribute 'legendInterface' problem

The following piece of code works well in QGIS 2.x, however it does not work in QGIS 3.x.  myDir = 'd:/work/output_folder/' layers = iface.legendInterface().layers() pipe = QgsRasterPipe() for layer in layers:  extent = layer.extent()  width, height = layer.width(), layer.height()  renderer = layer.renderer()  provider=layer.dataProvider()  crs = layer.crs().toWkt()   pipe.set(provider.clone())  pipe.set(renderer.clone())  opts = ["COMPRESS=LZW"]   file_writer = QgsRasterFileWriter(myDir + layer.name() + ".tif")  file_writer.setCreateOptions(opts)  file_writer.writeRaster(pipe,       width,          height,          extent,          layer.crs())   This is the error I get when I run the code:  Traceback (most recent call last):   File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\code.py", line 91, in runcode     exec(code, self.locals)   File "<input>", line 1, in <module> AttributeError: 'QgisInterface' object has no attribute 'legendInterface'   Does someone know what has replaced 'legendInterface' in the new version or what other changes I might have to make to get this to run in QGIS 3.0?


How do I prevent my Illustrator graphics from distorting when I scale them?

I'm using Adobe Illustrator CS5.1. When I scale my vector graphic in illustrator down to a smaller size, the graphic itself distorts. I have multiple rectangles that are evenly spaced horizontally, and eye-balled evenly vertically. All the rectangles are the same size. When I scale the graphic down, the rectangles all change to different dimensions and do not maintain the same placement as before. How do I fix this?  Please check out the .ai file to see whats going on.


The thing is, I think I'm doing OK. I haven't been on SO for that long, but I put in the time, I get the votes and answers and I am currently on . But the thing is, no matter how hard I try, I won't beat . ,  and I'm not going to get his face off of the user league.  But even though he does very well, he gets most his points answering jQuery questions and I'm a C# guy. I envision user leagues based on tags. I know, tags can be changed and it may not be trivial to define how someone scored on a tag. But if you'd for instance include a user in a tag league when 50% of his answers are to questions with a specific tag, it could very well be representative. And at last, I'll have a chance again. EDIT: OK, it's official, I'm blind. @Pekka answered that this already exists. However, is there a chance that this could look as nice as the normal user league, including the week, quarter and year score?


I will be traveling from Oslo to Dubai through Doha with Qatar airways. When I arrive in Dubai I have 80 minutes to my next connecting flight (which is a separate ticket booked with the same airline) back to Doha again. By doing this you can save a lot money! But I`m wondering how the baggage is handled in Dubai before my flight back to Doha again?


Why did trying to access a single dimensional array of objects as double array change the underlying object

const arr = new Array(1);  arr[0] = {x: "first", y: "second"} arr[0][5] = "third" console.log(arr) // Result: [{5: "third", x: "first", y: "second"}]  Why did it add 5: "third" in the beginning like that? How does JS handle this under the hood?


Displaced margins in beamer footer after MikTeX update

I recently updated MikTeX on Windows 10, and now all my beamer slides are exported with 0 margin in the footer, so that the Author short name, short title etc is displayed all crammed up at the top of the footer. I am using CambridgeUS theme, but the problem is there in eg. Warsaw as well.  Minimal working example  \documentclass[10pt]{beamer} \usetheme{CambridgeUS}  \title[short title]{title}  \author[short author name]{author names}  \begin{document}  \begin{frame} Something text here \end{frame}  \end{document}   I've tried uninstalling and installing the beamer package to no avail, it looks like this when compiled:    Any help is greatly appreciated!


Is there a simple way to print any method's signature once it's entered?  My current naive solution is to add a System.out.print("method signature") statement before all the methods which prints its name, but then I have to do that even for every getter and setter which is quite tedious.


Booking travel tickets for visa without paying?

I am in the process of filling the forms for my wife and daughter (Chinese) to travel with me (British) to the UK for a short holiday. On the government advice located at  it says:     Accommodation and travel details      You may wish to submit  the following documents to help show us your   accommodation and travel arrangements in the UK and on which date you   intend to leave the UK. We advise that you do not make any payments   for accommodation,  travel and so on until you have received your   visa.          Details of accommodation and return   travel bookings         This could be:         hotel booking confirmation (usually email) travel booking   confirmation (can be email or copy of tickets) travel agent   confirmation of both accommodation details with a supporting letter    from the occupant confirming  that you are able to stay there      But how do you have tickets for a flight if you haven't made payments. All airlines I've seen require you to pay in full before they issue any tickets.  What is the best way to satisfy this requirement?


Our image styles are not getting created on one of the Drupal 7 sites in a multi-site installation. They are created for at least one of the other sites that uses the same Drupal 7 core.  Symptoms: Upon uploading an image to a node, the image preview does not get displayed (depending on the browser, a broken image placeholder may display). The image is not created in the file system either. I have verified file system ACLs. Both sites use the same .htaccess.


Handling of the post request and execute another script in PHP

So I have a PHP script that handles post requests. It works quite good, but (always a but) the data I am receiving is encoded. I need to run an external program to decode it. That also works.   My problem is, that my client connects to the server, does a POST and waits for the OK reply from the server, to verify that the post request has been handled correctly. Now when I add the part of the Decoder into my POST request handling script, it takes some time for my client to receive the OK from the server. It is only sending it back when the entire script has been finished, and not only the uploading of the files part, understandably.   What I was wondering now, can I do this in another way? When the uploading of the files is done, the client should now that the upload is finished. He should not have to worry about the decoding part. I also need it to decode immediately after the POST request has been handled, so I'm a bit puzzled at how I need to do this...   Don't really think I need to give out my code but if the need should arise i'll be glad to oblige.


How can I control my iPhone from my Mac?

Yes, there are a million ways to control your Mac from your iOS device, but I want to do the opposite.   The scenario is that I'm sitting at my computer, with my iPhone charging in a stand in front of me, and something on the device interrupts me.  I want to respond in a second or two, without having to remove the device from the stand, or take my hands away from my keyboard and trackpad.  I do not need to see the iPhone's screen on my computer's monitor.  Is this possible?  If so, how can I do it?  UPDATE  I am not asking , which is only concerned with controlling one single app, an entirely different situation.  To quote that question:     Actually, I really just need to control my own App, for testing purposes.   Nor am I asking  which is specifically about seeing the screen of a broken iPhone, which I explicitly stated I don't care about.


Positioning a div at the bottom of a fixed size container

I am having trouble finding a way to position a div at the bottom of the container.   What I tried:   position:absolute; bottom:10px;    But it displays the div I need at the bottom, outside the container in which I need it in...  I appreciate any help in this regard.  Heres the jsfiddle showing the example:


A post can be locked.   What does it mean to lock a post? Who can lock a post? When should a post be locked?


Ubuntu 20.04 interface font too small after restart, even with high scaling factor

So I was configuring VS code on my Notebook when suddenly I noticed that my interface font got really small on my desktop, terminal and files. I use Gnome Tweaks Tool to increase my scaling factor to 1,15 , but, even though it was active, the font stayed tiny. The solution I found was moving my scaling factor, which instantly fixed my font issue, however, every time I restart my Notebook the font gets tiny again and I have to repeat the process. I tried reseting my font configuration using this command, but had no success. gsettings reset org.gnome.desktop.interface text-scaling-factor  I also tried using the command dconf reset -f /  Finally, I tried using dconf-editor, but still had no success altering the font rendering DPI or changing the scaling factor. All of the steps I mentioned fixed my fonts temporarily, but the issue still persists when I restart my Notebook I am out of ideas and even considered getting a fresh Ubuntu install by now... My video card: NVIDIA GeForce GTX 1050 GPU


Every time I change the `figsize` the size does not change

Here is the code below. plt.figure(figsize=[15,7]) sm.tsa.seasonal_decompose(bitcoin_month.Weighted_Price).plot() print("Dickey–Fuller test: p=%f" % sm.tsa.stattools.adfuller(bitcoin_month.Weighted_Price)[1]) plt.show()  When I release it I get the following output.  Every time I change the figsize the size does not change. Please assist.


Why don't they make all DSLRs with an electronic shutter? Is it technically possible?  Surely this would allow easier syncing with flashes (rather than the usual 1/200s or 1/250s max).  I could even imagine a special RAW format that basically recorded all data from the CCD for, say, a second and then in software you could retrospectively shorten that time window. eg. only use data recorded in the first 1/100h of a second...  Or am I being stupid?


As a regular user, what is my incentive to continue to contribute?

I'm a half active user who has been mildly contributing to SO and SE, and I have watched the  arise over the last few weeks. Frankly, it disgusts me.  I'm not your top-of-the-bar high-rep user, I'm just an averagely contributing user, with a few answers here and there and some edits occasionally. I enjoy this casual participation and I have for the past year.  With the recent events I've started to lose faith in the platform. I positively contribute, like millions of others out there, and yet the company releases outlandish decisions and fails to listen/respond to the community. It's getting harder and harder for me to do my traditional contributions knowing there is a fire in the background that just keeps growing.  Here's my question that I'm asking as an average (not significant) contributor. What is my incentive to stay and continue to participate?  The reason I used to stay was because I liked the platform and I liked how democratic it was. But recently it seems like it's gone all down the drain. There's definitely better uses of my time and I can help others on other platforms more effectively.   This question really addresses the company as a whole:  if you expect me to help others on your platform, then why won't you treat me (and the other users that do a whole lot more than I do)  correctly?  Note: I'm not expecting a response from SE here. It would be great if they responded but that's probably not going to happen. So I'd also like to hear the community's thoughts.


How to say it about my brother in law guitar?

The most precious thing for me was .... a) my brother-in-law guitar b) my brother’s-in-law guitar c) my brother-in-law’s guitar d) my brother’-in-law guitar e) my brother’s-in-law’s guitar


I'm trying to make a welder-like transformer, but I'm having the problem that apparently I'm drawing too much current from the primary side of the transformer as the variac I'm using to supply about 10V is getting too hot. The variac is a chinese model rated for 20A, and unfortunately I have a 30A circuit and 30A fuse installed so the variac is smoking and trying to catch fire instead of fuse-blowing.   How can I limit the current on the primary side to 20A?  I did some calculations on the reactance of that coil and determined its current limiting capability is a very high current limit (293A, 0.001 H). The formula I'm using is 2 x PI x 60Hz x L = Ohms impedance. Whats puzzling to me is that this formula doesn't account for the magnetic permeability of the core or anything. Or is that already accounted for in the L reading? I measured the L via an LCR gauge across the coil wound around the transformer.  Another thing I'm wondering about is will an increase in current on the secondary side of a transformer (due to low resistance) cause an increase in current in the primary side?  I know the ratio of turns is inversely related to current (high voltage, low current : low voltage, high current), but isn't current determined by resistance of the load? Does a high current on secondary from low resistance cause a proportionately higher current on the primary?  Is a transformer like a set of 3 gears, with gear size being turns/voltage, the middle gear being flux, and the speed of the first and last gear being current? I like to visualize electronic components like water or physical machines.  Sorry for all the questions but this will sure help me out a bit.  My current course of action is to get an AC welding transformer and rewind the secondary with thick wire (2 ga) for high current output. I'm hoping that the primary's inductance is high enough to limit primary current to 20A (same as the welder's spec).   Thanks


I downloaded Apache httpd-2.4.18.tar.gz file. But I don't know how to install that one?!


Is there something similar to the "Open Command Window Here" Windows Powertoy for Mac OS? I've found a couple plugins through a google search but wanted to see what works best for developers out there.


How to align vertically beamer titlegraphics?

In a beamer presentation, I am using the following code to add logos on my title page:  \titlegraphic{   \includegraphics[width=3cm]{logo-lirmm.png}   \hspace*{0.75cm}~%   \includegraphics[width=3cm]{logo-york.png}   \hspace*{0.75cm}~%   \includegraphics[width=3cm]{logo-dc.png} }   This code aligns vertically the three logos at the bottom. How can I center them vertically?


How much space does my little file take up, exactly?

I was under the impression that tar does not compress files. Imagine my surprise when I tar up a million small files (du -h ~ 4.2G) and the resulting tar was a quarter of the size (ls -lh mytar.tar ~ 1.3G)!  Clearly these tiny files were taking up space beyond their reported size, and an  suggests that each non-empty file takes up at least 1KB regardless of it's size. But where does this 1KB come from, does it differ across filesystems (this is ext4), and does a 1.01 KB file take up 2KB?   In short, how do I measure the true file size, especially many files in a directory? I tried du --apparent-size -h and I'm only getting 437M so I quite confused at the three vastly different numbers.


How do I install Ubuntu through virtual box?

I have set up Ubuntu on virtual box. I have reached the stage where it says install or try Ubuntu. When I press try, it takes me through a series of steps that I am not sure of, for example , partitions. I do not know which options to select.


Please help identify an old scifi comic book ~1970-1990

I remember only last part of comic book:   There is a scene of attack (in space) against aliens, hero is flying space shuttle. He return to active duty, there is a war with enigmatic aliens, after hospital he is trained in virtual reality environment Main planet of aliens is spotted and humans send ship against it, journey in one direction takes several years, hibernation is needed. Near alien planet ship is hitted by meteor or advanced alien stealth rocket. Humans fight with aliens and use generators which slows down time/movements (now I know it was stasis field, inside it fight with melee weapon started, remember Einstein quote about next war after third world war) it makes rifles and lasers useless, instead of it humans use bows and swords, the year is around 3000DC After battle hero backs to Earth (50 or more passed), now it seems that there is peace between aliens and humans Faces of aliens are not shown even one time I think, they are humanoid and in space suits


I want to run a VPS for torrenting Ubuntu's upcoming release. Is it legal?  Some VPS providers are unsure about it.  I am not talking about modifying Ubuntu here. Just distributing the ones that Ubuntu already provides.


Controlling the value of 'this' in a jQuery event

I have created a 'control' using jQuery and used jQuery.extend to assist in making it as OO as possible.  During the initialisation of my control I wire up various click events like so  jQuery('#available input',              this.controlDiv).bind('click', this, this.availableCategoryClick);   Notice that I am pasing 'this' as the data argument in the bind method. I do this so that I can get at data attached to the control instance rather from the element that fires the click event.   This works perfectly, however i suspect there is a better way  Having used Prototype in the past, I remember a bind syntax that allowed you to control what the value of 'this' was in the event.  What is the jQuery way?


Why the language selection of babel affects the page number format?

I writing a report in spanish, and I would like the page numbers in the \frontmatter to be numbered with lowercase roman numbers. However, the selection of spanish in the babel package changes the configuration to something else (not sure if uppercase or small caps, but I think is the later).  Here's the MWE  \documentclass[12pt,letterpaper,oneside]{book} \usepackage[english]{babel} \usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}  \begin{document} \frontmatter \renewcommand\thepage{\lowercase{\roman{page}}} \tableofcontents \chapter{Introduction} Lorem ipsum dolor sit amet, consectetur adipiscing elit.   \mainmatter \chapter{More stuff} Ut sapien nisl, rutrum eget laoreet blandit, eleifend eu sapien. Cursus non.  \end{document}   That code gives the desired result. But changing the 2nd line to \usepackage[spanish]{babel} puts the page numbers in the frontmatter in a different format. How can I change them back to lowercase roman numbers?  Other questions in this forum deals with inconsistencies between the \tableofcontents and the actual format presented in the document, but I couldn't find the answer to this particular issue. Any help is appreciated. Thanks in advance


What are good settings to use for exposure bracketing?

I take exposure-bracketed photos on the Sony NEX-5R and exposure fuse them in Photomatix.  I've found that I've had to use exposure bracketing for low-light photos, to capture the shadows without blowing the highlights.  Is that a rough guideline on how many photos I should take, and how far apart in EV should they be? I currently take three photos, at 0, +2 and -2 EV, except in low-light, when I might take 0, +1.3 or 1.7, and +3 EV. Are these good settings, or is there no rule of thumb for this?


I recently changed the lighting in the viewport in the system preferences.    How can I rest the positions of the lights? The Reset to Default Value does not work. it simple sets them all to a top light.  How can I reset the direction of the lamps without restoring factory defaults?


Which book would you recommend for a dummy wanting to start studying acoustics, out of interest?

I've been very into acoustics lately, specifically the harmonic series. I find it fascinating how the harmonic series works as a sort of guideline to harmony, and how we base tuning systems on trying to estimate the intervals from the harmonic series.  As you've probably gathered already, I know close to nothing about acoustics. But I would love an acoustic textbook that's suitable for dummies like myself.


I have always been amazed by things like the Mandelbrot set. I share the view of most that it and the Koch snowflake are absolutely beautiful. I decided to get a deeper more mathematical knowledge of this, but sadly Wikipedia hasn't been of much help. I have a few questions to get me started on this then.   What does $z_{n+1} = z_n^2 + c$ mean? Do we take an initial value of $z_n$ and calculate successive points and go on plotting them on the complex plane?    What is its historical significance? I feel that knowing where something came from helps us appreciate it even more. Where did this equation first come from? Why was it required to be studied?    Those are my specific questions for the moment, but considering the fact that I am only trying to learn about fractals, I may not be very well equipped to be asking the right questions, in which case you could tell me anything else you think is worth mentioning.     EDIT: I have one specific concern about the equation. It says that $z$ and $c$ are complex numbers. All very good, apart from the fact that $\mathbb R$ is a subset of $\mathbb C$ so apparently the starting values can be real too. But wouldn't that lead to all points falling on the real line, and leading to a plain old line instead of the Mandelbrot Set that we know? Although I couldn't find any references(hence this question) wouldn't simply defining the initial values to be non-real be a little... arbitrary? I think I might have a wrong idea of what equation actually means then.


Failed to execute child process "net" when entering Nautilus

When typing either of the commands nautilus . or xdg-open . into terminal, they execute correctly, but with a warning:  Nautilus-Share-Message: Called "net usershare info" but it failed: Failed to execute child process “net” (No such file or directory)   As I say, it opens the file manager correctly and I can detect no further problems. There are several instances of users experiencing this message in other questions , but each of the questions either addresses a side-issue I'm not experiencing, or simply goes unanswered.    What does this message mean, and can I do anything to prevent it?


It has long been known that the gamma function is an extension (shift) of the factorial function defined on integers.   There were an infinite numbers of ways to continue the factorial, so what property does the gamma function have that makes/made us use it? (Also, this question is not about history, but the unique features of a gamma function.)


Css issues with vertically aligning text

So I am trying to make a header, but what I see is this:   So I was trying to vertically align the text (the image is out of frame) and I mostly just see Link1-5 all jumbled up together. Is there a simple fix to this?  <!DOCTYPE html>
                          Link             Link             Link             Link             Link


Algebraically compute $\lim_{x \to 0}\frac{\sin x}{x}$

I know that: $$\lim_{x \to 0}\frac{\sin x}{x} = 1$$  However all proofs I have seen resort to some kind of geometric appeal or otherwise fall to L'Hôpital's rule or Taylor series. However, I want an to see an proof that is purely algebraic (I mean least geometric intuition, mainly not diagrams to convince the reader of something, but obvious algebraic statements one after another) that uses nothing advanced like series and [I mean accessible to ordinary calculus beginner]... I do not want want elipson delta proofs but something that has quite evidently, no gaps.   Edit: Some comments have said sine cannot be defined without geometry or series. Well, I meant to say that we can assume that we know the unit circle definition. I only meant to say that we do not rely on diagrams in the proofs. We know the obvious facts that what sine  and radians are, etc. I did not mean it to take to formally and rigorously.    Hope you guys have some elegant and delightful proof of the kind. It is something which is bothering me for quite a while.


Show that the equation $x^2+y^2+z^2=x^2y^2$ has no integer solution,except $x=y=z=0$

Show that the equation $x^2+y^2+z^2=x^2y^2$ has no integer solution,except $x=y=z=0.$    Let one of the $x,y,z$ be even number.Let $x=2p$ $x^2+y^2+z^2=x^2y^2$ This gives $y^2+z^2$ is also even,which means either $y,z$ are both even or $y,z$ are both odd. So either $x=2p,y=2q,z=2r$ is the solution or $x=2p,y=2q+1,z=2r+1$ is the solution.I put $x=2p,y=2q+1,z=2r+1$ in the equation $x^2+y^2+z^2=x^2y^2$ and see that it does not satisfy both sides,so it is not the solution. When I put $x=2p,y=2q,z=2r$,i get $p^2+q^2+r^2=4p^2q^2$ I am confused here how to prove that $p^2+q^2+r^2=4p^2q^2$ does not hold true. Also i cannot solve when $x$ is odd which is the second case. Is my method correct?Please help me complete the solution.


How to suppress a message from a program while installing it to use in a bash program?

PROBLEM:  I have a program written in bash that does a lot of stuff like install new software on the system.  One of the programs it installs has an extravagant message appear where you get some info about usage and the configuration file and what it does if you don't edit the config file.  And then waits for user input.  This message is a dialog kind of message in a GUI:    The program that displays this message is portsentry and the system is Debian Stretch.  QUESTION:  How can I suppress this message so there is no communication between my program and the user?


Problem: Let X be a nonnegative random variable and $log X \sim N(0,1)$, prove that $\mathbb{E}[X^k] = e^{\frac{k^2}{2}}$.  I'm self learning probability in order to understand some theorems in number theory, and this problem came in a book I'm reading.   I know that $\mathbb{E}[X^k]=\mathbb{E}[e^{klog X }]=\int_{-\infty}^{\infty} e^{klog(x)}f_{X}(x)$.  Now, I'm pretty lost in the $f_{X}(x)$ part. I suppose the question is how can I link the logX which its distribution is known and the X but Im not sure what is allowed to use in these cases.   Any help would be really appreciated.   Thanks! :)


\endpspicture produces an error (for me) because it contains \fboxsep=0pt, and \fboxsep appears not to be undefined.  I thought perhaps I had accidentally deleted the file which contained the definition; so I tried to find where the definition was.  I did a search for \fboxsep in the entire CTAN ...\pstricks\base\   package without finding where it is defined.  What's going on?  EDIT: Various people have reported that it is defined in the LaTex kernel.  I am NOT a LaTex user and until very recently, \pstricks worked fine in PlainTex.  Was it decided that PsTricks is now a LaTex only package, or is it simply a bug in a new version?


Does $\int_1^\infty \sin (x\log x)\ dx$ converge or diverge?

Does $$\int_1^\infty \sin (x\log x) \ dx$$ converge or diverge?   I've tried some substitutions ($u = x\log x$, $u = \log x$). Also, I know that the integral $\int_1^\infty \sin x \ dx$ diverges, which leads me to think our integral behaves in the same manner.


This is related to  question. I think we should discourage "Belongs on S[OFU]" type comments. I think they encourage the OP to go to the indicated site and re-ask the question. Flagging/voting to move on the question should be sufficient. Assuming this is the case, would it be proper to flag those comments for mod removal to hopefully get them removed before a new user sees them and duplicates the question?  Or, another example:    Or, even worse, but this new (!) user probably just doesn't know better:


I have tried to use pick block on xbox but it will not get the data saved for what I pick even with other buttons.


Unable to login to Stack Exchange iOS application

I am being unable to log in to the Stack Exchange application on my iPhone 4S running iOS 8.1.   I am trying to log in using the Stack Exchange option but get the following:     'key' is not valid for passed   'access_token', token not found.   The app is version 1.2, the latest available.  This weird error is showing up each time I try to log in.


Good introductory book about general relativity at undergraduate level?

I am looking for a good introductory book about general relativity at undergraduate level.


How do I configure Apache 2 to run Perl CGI scripts?

I would like to configure Apache 2 running on Kubuntu to execute Perl CGI scripts. I've tried some steps that I came across by googling, but nothing seems to work.  What is the right way of achieving this?


I'm trying to declare a method inside class dynamically. For example :  class Foo (object):     def __init__ (self):         super(Foo, self).__init__()         dict_reference = {a:1, b:2, c:3}         # This will add atributes a,b and c ...         self.__dict__.update(dict_reference)         # ... but I want methods instead, like self.a() return 1         d = {}         for k in dict_reference.keys():             exec "def {method_name}(): return {data}".format(method_name=k, data=dict_reference[k]) in d         del d['__builtins__']         self.__dict__.update(d)         # That's the only solution I found so far ...   There is another solution ?  Cheers


I created a table with the following sql:  CREATE TABLE fens_mng_people_utf8 (   pidm varchar(16) NOT NULL default '',   fname varchar(32) NOT NULL default '',   mname varchar(32) default NULL,   lname varchar(32) NOT NULL default '',   KEY pidm (pidm) )CHARACTER SET utf8  DEFAULT CHARACTER SET utf8  COLLATE utf8_general_ci  DEFAULT COLLATE utf8_general_ci;   And some Turkish characters such as Ş appears as a html code &#350; even if I insert it directly with an sql not from a text document. And I am viewing it from phpmyadmin.  As a result, when I try to do such operations in my php:  SELECT * FROM  fens_mng_people_utf8 WHERE fname = '$fname' and lname = '$lname'   It returns null because $fname and $lname both displays Turkish characters properly.  I either want to correctly display Turkish characters in my table or convert $fname as it would match the value in my database.  Thanks for the help!


I came to Frankfurt about 5 months ago with a tourist visa that is already expired. I decided to stay more time because I met a very special person (my current girlfriend) and I had hoped to find a way to legalize my situation here but I found out that is not possible so I decided to go back to my country Colombia with her and plan to come back legal.   I know that in the airport they will let me go out, but I am afraid to get a ban for the next months/years and I really would like to minimize that. I have talked with a lawyer and he told me that Frankfurt is very strict about this issue and I can get a penal infraction. He recommend me to flight out by Madrid because there, it is only an administrative procedure. So my current plan is to rent a car with my girlfriend and drive to Spain for 16 hours and leave EU.  It is worth to do this? I am trying to minimize the possibilities to get a ban.


Inverted layer mask not working as expected

Consider the following gradient:    Now I create a solid color layer and copy-paste the gradient as its layer mask.  Where the mask is white I got 100% opacity and where the mask is black I got 0% opacity, with a fading in between.  The result looks like this (visibility for the gradient layer is off):    At this point I duplicate the solid color layer and invert the mask of the new layer (Colors → Invert in GIMP).  What I expect is that the opacity of the new layer should be complementary to the first one, so having the two layers stacked one on top of the other should result in a solid color.  This is what I get instead:    Why is this happening and how to get what I want instead?


I have one problem about basic probability theory.     Let X be a random variable of the discrete type with pmf p(x) that is positive on the nonnegative integers and is equal to zero elsewhere. Show that       $$ E(X) = \sum\limits_{x=0}^\infty [1-F(x)],  $$      where F(x) is the cdf of X.   When I expand the right hand side (by substituting $F(x)$ with $p(1) + p(2) + ... + p(x)$), I can "see" that the right hand side turns out to be $1*p(1) + 2*p(2) + 3*p(3) + ... $ (which is exactly the expectation of X). However, I am having some trouble formalizing this idea (i.e., proving the equation above formally).   Can someone please help me ?  Thanks.


Voltage conversion between multiple orders

I have this circuit in which I want to convert the input voltage of micro order to volt. The circuit image has been posted. I have figured out the bandpass filter ( basically everything after the big vertical dotted line).  What I can't figure out is that the input offset voltage of AD620 is 30 micro volt. So it could create a problem. For that I have read that you need to use a capacitor in series with the feedback resistor but I don't know how to calculate the value. If anyone has a better idea about this please do suggest! Also another doubt I have is whether the comparator (TL084CN) after the instrumentation amplifier (AD620) will be able to shoot the milli order voltage to near Vcc value or at least bring it into order of volt? The shape of the signal doesn't matter to me but only the frequency does . So I'm trying to shoot the voltage up before passing it into the bandpass filter. If you have understood my goal and have better modifications to the circuit please let me know!  Datasheet used:     Image of the circuit: PS: The gain is 883 due to the 56 ohm resistor at instrumentation amplifier (not clearly seen in the image) ]


What's the policy on crossposting unnoticed posts from beta communities?

I have posted a question that in my opinion fits best into a beta community.  Overall, the attention was not satisfactory although I even posted a bounty and the limited response I got was positive. Despite currently being the only bountied question it has been viewed about 30 times in 10 days and about a third of the views seem to be my own. I believe the question itself should be relatively easy to answer for people familiar with the subject, hence I believe the low impact is related to the early beta stage of the community.  Is it acceptable to cross-post an unnoticed question from a beta community into a more mature related but thematically less on-point community?   For reference, the beta community under consideration is Earth Sciences; I'm considering a cross-post into Physics and the relevant question () is about radar.  Edit: Generally, cross-posting is deemed unacceptable (). However, this question seems to be a special case of the above. I can see a point to be made, that cross-posting is never allowed and that the beta status is irrelevant. At the same time I can see an argument for the opposing viewpoint, since many sensible strategies proposed in the case of mature sites (i.e. rephrasing the question, editing the question....) may not be helpful if the general traffic on a beta site is so low that the answer is simply not read by anyone, hence I feel that my question is not a straight forward application of the above one.


If I do   $ cat > file.txt      textCtrl-DCtrl-D   Question 1: If I don't press enter, why do I have to press Ctrl-D twice?  If I do  $ cat > file.txt      pa bam pshhhCtrl-Z   [2]+  Stopped         cat > file.txt $ cat file.txt $ cat > file.txt      pa bam pshhh      Ctrl-Z   [2]+  Stopped         cat > file.txt $ cat file.txt pa bam pshhh   Why is the second time the file with 1 line?


A short story I read long ago about the phone system 'waking up'

I am looking for a short story I read long ago about the phone system 'waking up'. It talks about how the phone system had just reached the number of connections as the number in the human brain. They lead you somehow to wonder (maybe characters speculating?) and it ends with a 'baby cry' of all the phones in the world ringing. I think I read it at least 20 years ago, maybe as many as 30. I think it was after 1978 because I think it was after I went to work at Bell Labs - so the phone connection resonated:-). It was definitely pre-internet.   What was the title? Who was the author? Any more on the plot since my memory is very hazy? I remember really liking the story and this site has got me thinking about my ATF's.


Group with order $pq$ has subgroups of order $p$ and $q$

Let G be a group with $o(G)=pq$, $p>q$ are primes.  Prove that $G$ has a subgroup of order $p$ and a subgroup of order $q$.  Remark: I cannot find the topic with this problem.  I have tried different methods but no one of them did not bring result. Please show how to do that. Do not use Sylow's Theorem.


Does the angle of refraction always have $n_2$ as its refractive index? As far as I know, $$\frac{\sin\theta_i}{\sin\theta_r} = \frac{n_2}{n_1}.$$ So I got this question here:      Calculate the critical angle for a flint glass-air ($n=1.58$)  boundary.    Since the critical angle has an angle of refraction of 90° that is $\theta_r= 90^\circ$, but I am confused on what values should I substitute for $n_2$ and $n_1$. So does the refractive index of the angle of incidence always equal $n_1$?


I am trying to find the probability density of ln(1/X) which can be rewritten as -ln(X) so to find the probability density I first want to find the distribution function. I am not sure how to do so, can somebody help me with determining this? I am looking at when x is uniformly distributed with 0 < X < 1.


find a limit of $\lim_{n\rightarrow\infty}\left(\frac{a^{1/n}+b^{1/n}}{2}\right)^n$

$$\lim_{n\rightarrow\infty}\left(\frac{a^{1/n}+b^{1/n}}{2}\right)^n$$  No idea how to do it please help step by step


No user name/password required when exploring from live USB?

A few months back when I buggered up my netbook and then booted into it to get information from it using a live USB. (Thinking that was 10.10)   When I was copy/pasting this to another USB at no time was I required to enter my user name or password to access this information. Why and how was that possible? Shouldn't that not be possible? This was information from the 'home' including documents, pictures, music, videos and some other locations.  This does not sound secure at all, is there any way that I can ensure this cannot happen again and that user name and password would be required to access information on my installed Ubuntu computer when booting on that computer from a live USB/CD/DVD?


How do you mount a partition locked by Windows hibernation without dual boot

I've installed Ubuntu on a friend's laptop, completely replacing Windows 8. He has a backup ntfs partition that I left untouched after the operating system was replaced. I get an error in Nautilus when I try to mount; it's because of Windows hibernation from what I've read. The problem is, I didn't keep the Windows partition.  Is there a way to mount and unlock the partition without booting to Windows 8?  I thought to post this question even when I'm well aware of that one referred to as the original because there it assumes that dual boot is still available. The top answer shows that, and closes off responses for my situation. I needed an answer for when the Windows boot is no longer available.


Wedge product of Lie algebra valued differential forms

Let $\mathfrak{g}$ be the Lie algebra of a matrix Lie group. Furthermore, let us consider the following $\mathfrak{g}$-valued $p$-form and $\mathfrak{g}$-valued $q$-form: \begin{equation} \begin{array}{cc} \zeta = \zeta^\alpha \otimes T_\alpha \; ,& \eta = \eta^\alpha \otimes T_\alpha \end{array} \end{equation} where $\zeta^\alpha \in \Omega^p(P)$, $\eta^\alpha \in \Omega^q(P)$ and $\{ T_\alpha \}$ is a basis of $\mathfrak{g}$. Then  I'm trying to show that: \begin{equation} \zeta \wedge \eta = T_\alpha T_\beta \zeta^\alpha \wedge \eta^\beta \tag{1} \end{equation} Can someone help me or give me a nudge in the right direction? The only possibility I see is using the definition: \begin{equation} (\zeta \wedge \eta)(X_1,\ldots,X_{p+q}) = \frac{1}{p!q!} \sum\limits_{P \in S_r} \mathrm{sgn}(P) \zeta(X_{P(1)},\ldots,X_{P(p)}) \eta (X_{P(p+1)},\ldots,X_{P(p+q)}) \end{equation} but is don't really understand how to manipulate this in order to get equation $(1)$.  I'm not sure if the notation used above is conventional notation for mathematicians, so please let me know if I need to clarify anything.


I am trying to return a dictionary with key/value pairs, but this is what I got and it does not work. def lists_to_dict(keys, value):     for i in values:         value[i]=map(int, value[i])         return keys


How can I run an application while another application is running?

I want to run an application when some other application is running. e.g. in a script I start an application:  #!/bin/sh bob   and this application will run for a large amount of time. However, I want to run another application alice (that will be using bob's results) 5 seconds after starting bob. How should I proceed?


I want to know more about how to correlate the color of meat to its level of doneness. How do I recognize how cooked my meat is based solely on color?


Calculate the average temperature needed for hydrogen fusion reaction

my question is simple. How can we calculate the temperature needed in order to do the nuclear fusion things , and also the temperature after the reaction successful.    If you can describe it, it would be really cool. I just want to know about it  Thanks


Had my website hacked through a plugin 3 weeks ago.  rebuilt the site with a new wordpress site (hosted on Godaddy wordpress pro).  this was a fresh build.  All the built in malware checks in wordpress plugins and also google's console checks are good and clean.  Google ads wont run as it reports I have three malicious links in my website.  They gave me the link addresses but they are nothing I can locate.  Anyone have ideas on how to find what google found?


Why do some bones in my armature disappear when I go into Edit mode?

I made a rig for a model of a dragon and for some reason, when I go into Edit Mode, some of the bones disappear:    I don't know if this is relevant or not, but I created the rig using the standard release of 2.69, but now I'm using the standard version of 2.70.


I am trying to write a program to calculate the resulting bearing of the addition of two vectors. Magnitude is not required.  The bearing is defined as the bearing of the tip of the second vector from the tail of the first vector.  The program crashes when I tried to run it. Also I'm aware that the functions are not returning expected results.  Any help appreciated. Thanks in advance.  #include <iostream> #include <math.h>  #define PI 3.14159265358979323846264338  using namespace std;  int _atan(int y, int x) {     if (x=0)     {         return 90*abs(y)/y;     }     else     {         return atan(y/x)*180/PI;     } }  int _bearing(int x0, int y0, int x1, int y1) {     int bearing;     bearing=90-_atan(y1-y0, x1-x0);     if (bearing<0)     {         bearing=bearing+360;     }     return bearing; }  int _vectorAdd(int m1, int b1, int m2, int b2) {     _bearing(0, 0, m1*sin(b1)+m2*sin(b2), m1*cos(b1)+m2*cos(b2)); }  int main() {     int m1;     int b1;     int m2;     int b2;     scanf("%d %d %d %d", &m1, &b1, &m2, &b2);     printf("%d\n", _vectorAdd(m1, b1, m2, b2)); }


I'm doing a bit of archviz for a buddy's bathroom remodel, and I want the windows and reflective surfaces to show a background without it darkening the scene. I think in 2.79 you could set the object to not cast shadows, but that seems to have been removed. I know I could use view layers, but A. I'm very confused by them, despite them ironically being made to supposedly be easier than the old method, and B. Next to a window is a glass plane that reflects the environment, and I don't know how I'd composite that in. I've also added in an external ground plane to get some ground color bounces.     Of note is the image with the background is blocking a lot of sun and sky light, so it's darker overall.


I notice the Serbia's flag has been added to  but doesn't work on the game yet.  I would like to ask Agar.io to add Serbia's flag. Does anybody knows how I can do that? Thanks!


I have an array. I would like to write its items in a random order every time I call. My array is this.    string[] a= {"A","B","C","D","F"}; string[] a= new string[5];   For example the order should be like this  C D F A B  But it should change the order.


How to generate a predetermined number of pulses?

Motivation: I have a grinder that spawns spiders which are then moved to a very small space. When they accumulate in big enough numbers, I pull a lever and let a piston crush them 11 times. Then I can kill them with one hit and harvest experience.     This becomes a problem once there are a lot of spiders - the game starts to lag and it is difficult (if not impossible) to have the precise number of hits.   Question: For some n, how do I create a circuit that generates n impulses before shutting down? Or in this case, how do I make a piston hit exactly 11 times?


How to log user in to multiple drupal sites?

I have multiple drupal sites on the same server (VPS). Thise sites has separated d7 core and db. All sites has own domains: domain1.com, domain2.com, domain3.com..  When user logs in to one site I need him to log also in to the another site. This should be done in single sign on so user does not have to log first to one site and then to another.  How to automatically log user in to the both/multiple sites?


Couldn't find solution to my problem so making a new thread. My controller can't work unless plugged in ps/pc It works perfectly fine on cable but as soon as I unplug it it just turns off. Also can't be turned on/no led light without being plugged. I tried resetting it Then check the battery with multimeter- holds normal amount of charge. No issues with the usb port, no issue with ps button or the conductive mat under all buttons Tried resetting connections with PS+share Tried different cables/ports Tried restarting the ps There is no obvious sign of damage on the motherboard. And I have no idea what could be the problem. Any ideas?


Include values of \ref, \eqref into a new document

I have an introduction to my thesis. It includes a lot of constructions like in Section \ref{sec1} is shown or the formula is given in \eqref{eq1} whereas the corresponding Section and equation are in the separate files. Everything works fine and I have a correct pdf with explicit numbers, say, "in Section 3.2" or "is given in (5.3)" instead of \ref and \eqref.  For some reasons, I nead to have this introduction as a separate document. However, I still need to have the explicit numbers in proper places. Hence, my question is the following: is it possible to obtain from the existing thesis a new tex-document which will have instead of \ref{Sec1} its value "3.2" and so on?


MySQL Workbench GUI problems in Ubuntu 14.10

I've recently performed a clean install of Ubuntu 14.10. I got Apache, PHP and MySQL from Ubuntu's repositories, then installed MySQL Workbench (6.1.7) from the Ubuntu Software Center. It almost works - there are just two "little" issues, one of which makes the program unusable:   After opening the .mwb file it shows in the schema tab: Tables (X items), but no tables are shown below - just Views (X items) etc., which are also not listed at all. For some reason menu in the title bar is triplicated...   Has anyone encountered these issues or has an idea how to solve them? I tried mysql-workbench-community 6.2 from Oracle website, but it's the same.  I posted a screenshot below.


Regarding the firestorm that was Monica's firing, mods resigning, SE non-apologizing, then backpedaling, then apologizing, then putting out the wildly negatively received FAQ on the new CoC regarding pronouns, it's been pretty hard to follow, hard to understand, and frustrating to hear about.  What hasn't been hard to follow and identify, however, is the both explicit and subtle instances of homophobia, queerphobia, and transphobia that have emerged.  I suppose, since most everyone is frustrated with the new pronoun CoC, LGBT-phobes have decided they can blend their bigotry in with the general and appropriate outrage that isn't directed at the LGBT+ users on SE, but rather SE's mishandling of an important issue.  As a queer woman, seeing comments with lots of upvotes criticizing queer and trans users and blaming this mess on them, lamenting political correctness that requires you refer to someone how they'd like you to, and anger at the fact that SE sort of, maybe, at the very beginning, wanted to protect LGBT users, is very troubling and uncomfortable for me to see.  I feel, right now, with all of this in mind, like I can't be open about my identity on SE.  To my fellow LGBT+ users, do you feel the same way?  If this is the case with others as well (and me hopefully not just being a snowflake), how can we fix this?  Most importantly, can we fix this?   (My question is, is this issue fixable, not, is it an issue.)


I spent some time studying about temperatures and color of objects. It turns out that as we heat something it turns to red, then yellowish white and if we heat it more it turns to bluish-white.  Like we can say a blue star is hotter than a red star. But why isn't it the same with flames?  Blue flame isn't always hotter than a red flame. It's just the chemistry of it all.   I mean I know the electrons jump from one orbit to another and gets into excited state when heated.  But the questions in my mind are:   If one object appears blue and another red, that doesn't always mean that the blue object is hotter than red. Is that correct? If yes then how is it so? I am sorry but I'm bit confused over it. With the "Color Temperature" concept on Wikipedia. They say 1,700 K to match a flame. But 15,000–27,000 K for a clear blue poleward sky.   This confuses me. The sky appears blue, does that mean its hot? But it isn't right? It's colder. I am not sure if I'm able to frame it properly. It's a bit confusing to me.  Is this something like a glowing object vs reflecting object? The sun is white but Earth is blue. But sun is hotter than the earth. It's the sun radiating light but earth is just scattering it.  But the surface temperature of sun is 5778K while the Wikipedia states our sky is about 15000K-27000... I know there's something I'm missing here. I'm hoping someone can tell me what is it.


wchar_t* Pfad;     wcin >> Pfad;  wchar_t* file = Pfad + "*.quiz";   Not working for me, how can I make this work? It says "*.quiz" is wrong, something like it has to be a numeric value or something like that.  Well sorry, I am new to c++...  and my actual problem is, I use this, but I want to user to select the path  something like cin >> file  but I don't want the user to have to type "*.quiz";  wchar_t* file = L"C:/Users/Niku/Documents/Visual Studio 2012/Projects/Quiz/Quiz/Fragen_Niko/*.quiz";  WIN32_FIND_DATA FindFileData;  HANDLE hFind; hFind = FindFirstFile(file, &FindFileData);   if( hFind != INVALID_HANDLE_VALUE ) { max++; while ((x = FindNextFile(hFind, &FindFileData)) == TRUE) max++; }   If I use anything else besides wchar_t* it's not working..


How to see the history of all files/folders and programs that where added to pc?

I noticed a big jump in used space on my C: drive and i want to see what is the cause of that. Is there a way to see the history of all files/folders and programs added to my pc? (Using Windows 10)


Imaginary part of the waveefunction in quantum mechanics

I wonder what is the reason for wave function in quantum mechanics to have an imaginary part... How do we interpret the utility of the imaginary part?! As we know the wave function it self does not have any physical meaning but why should it have an imaginary part as well?


Billingcity picklist same as like country and state

I am using Below code to get the Country and State picklist on Account.   <apex:inputfield value="{!Account.Billingcountrycode}" ></apex:inputfield>  <apex:inputfield value="{!Account.Billingstatecode}" </apex:inputfield>   is it possible to use BillingCity based on selected Billingstatecode. I have tried with Billingcitycode but its is not working.


WhatsApp web and desktop app displaying broken QR codes

I recently bought a new laptop and when I tried to set up the WhatsApp Desktop app, the QR code won't scan on my phone. The same is the case with WhatsApp Web as well. I tried doing the following things but still didn't work out:  Trying WhatsApp Web with a different browser Clearing cookies and cache Restarting the computer  I think the problem is with the QR code that is being displayed on my new laptop. It appears to be broken since there are white spaces where they shouldn't be as shown in the image. This happens with both the WhatsApp Desktop app and the WhatsApp web.  What might be the reason for this and how to fix it? PS: WhatsApp Web works fine on my old laptop. So it's definitely not a problem with the Android app on my phone.


Adding JSON layer in Leaflet just like GeoJSON data?

I am trying to add different layers to a leaflet map. Now i really want these layers in order to add features like zoom. With GeoJSON file this was easy but I am not getting a good way to plot array data from JSON response of this sort [[1,2],[ 3,4],[5,6]] :  So basically my question is how can I group latlng points together to form a layer equivalent to how layer is provided in L.geoJson.  I have done some work in this direction:  placePointsOnMap(){         let markerParams = {             stroke: true,             radius: 3,             fillColor: 'blue',             color: 'black',             weight: 2,             opacity: 1,             fillOpacity: 1,          };         for(let i of this.state.points){             console.log("ii", i);             L.circleMarker(i, markerParams).addTo(this.miniMap);         }     }   But this is not how I want points to be displayed, instead I want this to be a part of layers feature provided by leaflet allLayers = L.layerGroup([]);  this.geojsonPointsLayer = L.geoJSON(this.state.geoJSON, {             onEachFeature: this.onEachFeatureFunction.bind(this),             pointToLayer: this.pointToLayerFunction.bind(this),             filter: this.filterPointsAsRequired.bind(this)         });


I read from my textbook that $\text{cov}(X,Y)=0$ does not guarantee X and Y are independent. But if they are independent, their covariance must be 0. I could not think of any proper example yet; could someone provide one?


make Linq to Sql compiled queries for insert and update

I am making select compiled queries as shown   but my question is how to make compiled queries for Insert and Update?  mine Insert query is  DataClassesDataContext db = new DataClassesDataContext(); tbl_desc_index tabledesc = new tbl_desc_index(); tabledesc.ed_journal_id = Convert.ToInt32(Server.HtmlEncode(Request.Cookies["j_id"].Value)); tabledesc.editor_id = Convert.ToInt32(Server.HtmlEncode(Request.Cookies["editorid"].Value)); tabledesc.short_desc = ck1.Text; tabledesc.abt_journal = ck2.Text; tabledesc.aim_scope = ck3.Text; tabledesc.indexed_in = ck4.Text; db.tbl_desc_indexes.InsertOnSubmit(tabledesc); db.SubmitChanges();   Update query is   DataClassesDataContext db = new DataClassesDataContext();  var update = db.tbl_desc_indexes.First(p => p.ed_journal_id == Convert.ToInt32(Server.HtmlEncode(Request.Cookies["j_id"].Value)) && p.editor_id == Convert.ToInt32(Server.HtmlEncode(Request.Cookies["editorid"].Value)));   update.short_desc = ck1.Text;  update.abt_journal = ck2.Text;  update.aim_scope = ck3.Text;  update.indexed_in = ck4.Text;               db.SubmitChanges();


I just learned that about 1/1000 of hydrogen is deuterium. Does that mean 1/1000 of water is D2O, which is heavier and sinks to the bottom in a glass of water? And consequently is there a layer of D2O at the bottom of the ocean? thanks!


Prove by mathematical induction that $\forall n \geq 4 \in \mathbb{N}: 3n^2 + 3n +1 < 2(3^n)$

Prove by mathematical induction that  $$\forall n \geq 4 \in \mathbb{N}: 3n^2 + 3n +1 < 2(3^n)$$  Step 1: Show that the statement is true for n = 4:  $$3(4)^2 + 3(4) +1 < 2(3^4)$$  Which simplifies to $61 < 162$. That completes the base case.  Step 2: Show that if the statement is true for $n = p$, it is true for $n = p + 1$:  $$3(p+1)^2 + 3(p+1) + 1 =$$ $$3(p^2 + 2p + 1) + 3p + 3 + 1 =$$ $$3p^2 + 3p + 1 + 6p + 6$$ $$ < 2(3^p) + 6p + 6$$  All that is required now is to show that $6p + 6 \leq 4(3^p)$ since $2(3^{p+1}) = 6(3^p)$. Does this require another proof by mathematical induction or is it sufficiently rigorous to say something like "well, $x^p$ clearly grows faster than $px$ as $p$ approaches infinity, so the inequality is trivial"?  In a larger context, are there any specific rules for when inequalities can be considered trivial?


How to check if FileTable is enabled in SQL Server database

Before I store data into SQL Server FileTable, I need to know or verify that the FileTable exists in the database, then only I can add the records to FileTable.   If FileTable is not enabled or added to Database then I want to store the data in the BLOB. Anybody can help me with a stored proc which can tell me weather the Filetable exists in the database?


What are the ways of finding the spin of a particle

How many ways are there for this mission? Any article about that on the internet. I heard about TODAI made a reprogrammable quantum computer.   Any more ideas are welcome


I would like to have some notes for my presentation so that I would be the only one to see them on my computer. So I used the show notes option of beamer.    However, I need a software to read the presentation. As I'm on OS X,I tried splitshow but it seems they have some issues with their last release it doesn't work.   Does anyone know how I could manage to do what I want ? (Another soft ? Another way ?)  Thanks in advance for your help


How can I get my coordinates in Minecraft pocket edition?

I want to use the /fill command, but I need my coordinates in order to use it. How can I get my coordinates in Minecraft Pocket Edition?


Do Booming Blade and the Spell Sniper feat stack?

If you have the spell sniper feat (doubles range of spells), and you use a weapon with reach, can you cast booming blade and hit a creature at 10ft? Can you also combine this with the feats Polearm Master and War Caster to make a booming blade opportunity attack when a creature enters your reach (of 10ft)?


I'm looking for tool that will be convert  WMS to vector layer.  Are they ready tool?(for example in python)


Can a weak form of the union axiom be proved in ZF set theory?

I read somewhere that the statement "$x \cup y$ exists for every $x$ and $y$" can be proven in $ZFC$ set theory without using the full strength of the union axiom, which says that arbitrary unions exist, not just binary unions. Can that statement also be proven from $ZF$ set theory? Is this an open problem?


I'm trying to change text by variable (language), but even when value of language variable is "albanian" , text of buttons are not changing!  P.S variable value is passed from another activity.  String language=""; @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.single_level_activity_layout);      btnBegginer=(Button)findViewById(R.id.btnBegginer);     btnMedium=(Button)findViewById(R.id.btnMedium);     btnHard=(Button)findViewById(R.id.btnHard);      Intent objIntent=getIntent();     language=objIntent.getStringExtra("language");      //Toast.makeText(getApplicationContext(),language,Toast.LENGTH_LONG).show();      if (language=="albanian")     {         btnBegginer.setText("FILLESTAR");         btnMedium.setText("MESATARE");         btnHard.setText("VESHTIRE");     }     else     {         btnBegginer.setText("BEGGINER");         btnMedium.setText("MEDIUM");         btnHard.setText("HARD");     }


So...  I am making a simplish maze game.  My Issue at the moment is with making the character jump. I have a keyboard sensor for SPACEBAR that when the player presses it, it gives them 0.05 motion upwards.  Well, you keep going upwards until you let go of SPACEBAR, and when you do, you go slamming back down to the ground.  Another thing, you can jump 1. when your in the middle of a jump, or when you have fallen off the edge...


I would like to know if it is good practice, and if so how it can be achieved, to make references like: "as mentioned above...". Or am I going too far and should just type the word?  I've read something about varioref, but it seems to produce page or section numbers, but I can't find how you can just print if a section is above or below the reference.


Linear Algebra and Invertibility of Matrices

Given Square Matrices A,B,C such that $$\begin{cases} A+B+C+\lambda AB=O \\ A+B+C+ \lambda BC=O \\ A+B+C+ \lambda CA=O \end{cases}$$ and $\lambda$ a real nonzero number, show that  $I+\lambda A, I+\lambda B, \textrm{ and } I+\lambda C$ are invertible, that $AB=BC=CA,$ and that $A=B=C.$


I tried to setup apache 2.2 in amazon aws using amazon ami. i did installed httpd and php and congirue http.conf to use /var/www/html.  Then put file index.html on that folder. But when i tried to use browser to browse my domain which is ec2-122-248-255-181.ap-southeast-1.compute.amazonaws.com, nothing was loaded.  I did start httpd by running apachectl start, and i can see it listening on port 80.  Does anybody know what is wrong?


Help, i tried installing kaltools and my Ubuntu is messed up!

I tried installing Kali Linux tools.  I started installing some tools and there were several things I had to "agree" to and one message said add users... something in terminal, and when I came back I saw terminal reporting removing a bunch of core programs that I needed. I canceled the process but I don't know if I should reinstall Ubuntu or not.  How can I repair my system?


Mathcontext needed for add, subtract and multiply?

first of, my search skills may be not as good as I hoped, so maybe this kind of question exists already. If so please tell me..  See this code below:  new BigDecimal("5").add(new BigDecimal("7"));   vs  new BigDecimal("5").add(new BigDecimal("7"), mathContext);   In which situations would I really need a mathcontext (except divisions)?  I never use a mathcontext unless I divide something. As far as I know this always worked, so what may be the drawbacks here? Do I need a mathcontext on add, subtract and multiply? I'm not so good into the BigDecimal, I simply want to use it to not lose any information like when using doubles. As I sometimes see code with mathcontext on adding something, I'm too afraid to just remove it only because it's my opinion that it is useless...    I read that  but didn't really find a proper answer to my specific question... I begin with BigDecimals without mathcontext and then calculate with them. So my question is, will I ever have drawbacks with this regarding information loss / precision etc? Or will this simply lead to maximum information and that's it?  Edit: I don't want to round, never. In cases of a division like 1/3 I would have to, of course, but in the cases of add, multiply and subtract I don't want any rounding. Do I then need a mathcontext in any circumstance?


I would like a suggestion on the best way on how to calculate a weighted median in R.  I have this kind of dataframe:  id         2       5        10 1       5408.55    0.00     0.00 10      1158.51    0.00     1006.37 100     18263.69   4205.64  0.00 20      27483.89   7601.01  833.90    id is the sample unit  2, 5, 10 are categories, but also the value from which I want to compute the median (equal for each sample unit).   At the coloumn-row intersections there are the weighs I want to use for the weighted median.  Any suggestion on which is the best package/functions doing this operation?  Thank you


Why Empty universe have to obey the Negative Curvature?

For empty universe it seems to me that we can have two solutions. $$H^2=\frac {8\pi G\epsilon} {3c^2}-\frac {\kappa c^2} {R^2a^2(t)}$$  For an empty universe when we set $\epsilon=0$ we get $$H^2=\frac {-\kappa c^2} {a^2(t)}$$  since the square cannot be  negative $\kappa$ must be $-1$, $\kappa=-1$  However I think, $\kappa=0$ is also a solution. But in one case $a(t)$ will be a constant, $a(t)=C$ since $\dot{a}(t)=0$,  in $\dot{a}(t)=c/R$ comes when we set $\kappa=-1$, in this case it seems to me that $a(t)=ct/R_0t_0$  Are these statements true? Since in general, empty universe which is also called the Milne universe, described by negative curvature. But cant be also described by a flat space ?


Is this reputation rollback because of a removed user correct?

I saw I lost some reputation over on  due to a removed user. Nothing unusual there. Until I saw the details.  Now I know that . But it looks suspiciously like the 6 separate -2 rollbacks were added together for another full -12 rollback. Is that what happened? I'd like to note that a -12 is not impossible, but — knowing my voting history on that Stack — it is implausible.


c sizeof operator different from my manual count, what's the extra?

I have a program that reads a bin, and stores data in an array of structs.  My problem is that all the variables of the struct (int, long, unsigned int, char[8] etc) counted manually should add up to 60. A provided .bin file with only 1 entry (which is confirmed to be correct), also counts as 60 bytes using the following code:  fseek(file, 0, SEEK_END); long int length = ftell(file); fseek(record, 0, SEEK_SET);   HOWEVER, when I'm assigning space, I'm using a printf statement to debug:  struct Data *entries = malloc(length); // length is 60 from above code printf("%d entries of size %ld", count, sizeof(struct Data)); // count is number of entries  // RESULT IN CONSOLE IS "1 entries of size 80"   So obviously, there's an extra 20 bytes when using sizeof(x). Why?   Also if that's the case, how DO I go about allocating the appropriate space, reading from a .bin file, if I don't know how many entries there are?  Thanks!  EDIT: This is the struct (mine):  struct Data{     unsigned int creator;     unsigned short fish;     short vacation;     char existence[8];     short front;     int bait;     short peace;     char night;     char burst;     unsigned long snow;      char finger;     double idea;     float goodbye;     int stocking;     char bell;     double grandfather; }


Utopia where no one has to work, but people want to work anyway

I'm looking for a short story that takes place in a sort of utopian future, where no one has to work because machines do everything. People can basically sit and do nothing all day, but this is unsatisfying for some. They end up getting a job where they go around and tighten screws that are loosened on the machinery due to their vibrations. They find this work satisfying, and work everyday.  At the end of the story, we learn that another crew wakes up every night and goes around loosening screws.


What is the best method to list all the files of an extension in a directory?

After some research, I ended up with few methods. The most logical one is,  muyustan@muyustan-ubuntu:~/Downloads$ find . -name "*.srt"   But the output of this command also includes the files on subdirectories of the working directory , which I don't intend to do.  ./The.Walking.Dead.S10E11.Morning.Star.720p.AMZN.WEB-DL.DD+5.1.H.264.srt ./the.walking.dead.s10e12.web.h264-xlf.srt ./The.Walking.Dead.S10E11.1080p.WEB.H264-XLF.srt ./fs9s/Friends - [9x04] - The One with the Sharks.srt ./fs9s/Friends - [9x16] - The One with the Boob Job.srt ./fs9s/Friends - [9x17] - The One with the Memorial Service.srt ./fs9s/Friends - [9x03] - The One with the Pediatrician.srt ./fs9s/Friends - [9x02] - The One Where Emma Cries.srt ./fs9s/Friends - [9x21] - The One with the Fertility Test.srt ./fs9s/Friends - [9x01] - The One Where No One Proposes.srt ./fs9s/Friends - [9x18] - The One with the Lottery.srt ./fs9s/Friends - [9x12] - The One with Phoebe's Rats.srt ./fs9s/Friends - [9x11] - The One Where Rachel Goes Back to Work.srt ./fs9s/Friends - [9x15] - The One with the Mugging.srt ./fs9s/Friends - [9x09] - The One with Rachel's Phone Number.srt ./fs9s/Friends - [9x07] - The One with Ross's Inappropriate Song.srt ./fs9s/Friends - [9x05] - The One with Phoebe's Birthday Dinner.srt ./fs9s/Friends - [9x08] - The One with Rachel's Other Sister.srt ./fs9s/Friends - [9x14] - The One with the Blind Dates.srt ./fs9s/Friends - [9x13] - The One Where Monica Sings.srt ./fs9s/Friends - [9x19] - The One with Rachel's Dream.srt ./fs9s/Friends - [9x20] - The One with the Soap Opera Party.srt ./fs9s/Friends - [9x06] - The One with the Male Nanny.srt ./fs9s/Friends - [9x22] - The One With The Donor.srt ./fs9s/Friends - [9x10] - The One with Christmas in Tulsa.srt muyustan@muyustan-ubuntu:~/Downloads$    So, I would be thankful if anyone supplies me with a neat method to do this.


How to rename the last number-string it finds with a zero-padded version and leave the rest of the filename alone?  AAA 2000-01-03 bbb 2001-03-04 page_1.pdf   To:  AAA 2000-01-03 bbb 2001-03-04 page_0001.pdf   See:     (on Stack Overflow)


What would be the nicest way to execute any code on post_status change. In our case we need execute a function the moment the post_status changes from draft to publish. As far as I can find there is nog action to do this.


I have NO idea what I'm doing :). I'm looking to buy some pots/pans for my appartment (just moved out). Considering these:    I want to spend under $250 and this seems like a good value for my money. Wanted to check with some experts before I take the plunge.   I'd ideally like to be able to washing machine whatever I buy...  Thanks!


Why there is the requirement for derivatives no higher than second order in free quantum field equations?

Why there is the requirement for derivatives no higher than second order in free quantum fields equations?   We can get the equations for the free fields of an arbitrary spin by using the requirements of linearity of the equations, derivatives no higher than second order. But why there is the second requirement? Is it connect with initial conditions $A_{\mu}(0), \partial^{\mu}A_{\nu}(0)$ for the field? For example, Schrodinger equation is first-order time-derivative equation, because we have the postulate that if we know the $\psi (\mathbf r , t)$ in the present, we know it in the future.


Can't read filenames in save dialog box. Names are too faint

I want to click on file to inherit the name for the file being saved. I can't read file names in the dialog box because the color is too faint. This is the same question as   That question does not have an answer but I don't have enough points to interact there so I have to post a new question.    Edited to add screen shots I tried to calibrate the monitor which no effect and did not change the readability of "unavailable" file names. I have added screenshots of previous operating systems to compare: Please tell me how Mojave is not to blame here:


Protocol for responding to a hasty-candidate down vote?

Situation   I posted a question.  Fairly quickly, there was a comment "not reproducible" and a downvote. On its face, the downvote would appear to be from the commenter, and that there was a single attempt to reproduce the problem (which is fair). Comment of "not reproducible" spurred me to branch down that path to find the crux of the answer. And I think I have found the answer (search limits tied to IP addresses) and that the problem is reproducible. Assuming that I have found the answer and post it, then how does the downvote on the question get lifted?    I do want to emphasize that the comment was helpful because it helped me "switch gears" in thinking about the problem. It was just unsettling to have something downvoted because (on its face) a single attempt to reproduce the problem failed.  If it helps, here's the question I posted:


jQuery id-begins-with trigger not working

I am having a very strange thing happening to me. I have never seen this before. I am not very knowledgeable in jQuery/Javascript, but to my untrained eye, this looks insane...  What is happening is that without the alert('hello') under the $(document).ready function, the ID-begins-with selector does not trigger (i.e., does not alert the "goodbye"). If I add the alert('hello') below the $(document).ready) function, suddenly, the alert('goodbye') words.  How is this possible?     I have also tried with .on():     The HTML element is initially added on page load, but can be changed if you filter the bootgrid table, hence I changed it to .on() as suggested in the comments.                      	   I then tried this (because the original  where the icon resides is also dynamically created):  $(document).on('click', 'a[id^="hash-"]', function(e){     e.preventDefault();     alert('goodbye'); });   Also unsuccessful...  Any help would be greatly appreciated.