Ubuntu 18.04 server - missing installation candidates while installing mysql-server 8

I just created a brand new VM with Ubuntu server 18.04 and took the same steps I did earlier on another server (also a brand new 18.04 installation), but this time while attempting to install the mysql-server 8.0 it was suddenly failing.  The steps I followed were:  wget -c https://dev.mysql.com/get/mysql-apt-config_0.8.10-1_all.deb  sudo dpkg -i mysql-apt-config_0.8.10-1_all.deb    This configured my sources.list to use the 8.0 instead of the 5.x version of mysql.  Executing apt-get install mysql-server, I got:   mysql-server : Depends: mysql-community-server (= 8.0.12-1ubuntu18.04) but it is not going to be installed   Despite having run commands such as apt-get clean, apt-get install -f and apt-get update several times, and apt-get upgrade not reporting any held packages, I found this odd. So I tried apt install mysql-community-server.  Which resulted in the same error, but with missing depends for mysql-community-server-core and libmecab2.  When running apt install libmecab2 it tells me it has no installation candidate, but according to the ubuntu packages website .  I couldn't see anything out of the ordinary in my sources.list either, and apt-get update isn't reporting any errors either.  What could be causing this installation to fail? I took the exact same steps on the physical server, and it worked perfectly on that machine.


Will google consider a UK language site and a US language site as duplicate?

I googled around this for some time now and the answer is not completely clear for me. I found a similar question here  but this was regarding a web-shop, which was exactly why it was easier to do.   The website I'm working on is not a web-shop. The us site will be on a subdomain: us.example.com   I wonder weather there is a way to make sure that google will not consider uk and us sites as duplicate? As the content on both sites will of course be quite similar. I do know about hreflang, but are there other things to be done to make it easier for google? Or do you have some good tips for this issue?


What is this verb noun association called in linguistics?

Not all verbs work with all nouns.  It is better to say "fix errors" than "solve errors", for example.  In linguistics, is there a name for semantic compatibilities between nouns and verbs that go before them like this?


From my understanding so far (at least I think) the password_hash() function generates a hash based on the algorithm in use, cost and the salt. While the password_verify uses the information provided from e.g. password_hash($pass, PASSWORD_BCRYPT, array('cost'=>10)) to check if the retuned value is true or false as it contains all the information necessary for verifying.  I previously used   $SQL_Query = "SELECT * FROM DB_Table WHERE userName = '".$username."'" AND password = $ID;  which would work as they were stored in plain text and could return true whereas logically it won't work this time around.  I have came across similar questions where they use static passwords in explanations such as  <?php  $to_verify = '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';  if (password_verify('rasmuslerdorf', $to_verify))  {     echo 'Password is valid!';  } else  {     echo 'Wrong password.'; }   The concept I am having trouble understanding is how one would check the password input against the hashed value if it is stored in a database rather than the being known by the page at that point in time? I recently got help regarding storing the values which was a silly error on my part but I guess this isn't clicking with me as well as I hoped for the moment.


Hello I have been playing CS:GO all week and only gotten 1 case and 1 camo drop. I am on reduced earned xp for whatever reason if that matters. Have I reached my limit for this week or is there even a weekly limit?


How can I implement rectangle collision response?

I am working on a game in JavaScript and my current implementation of collision uses the shortest distance to push the intersecting object away, which isn't always correct. I've made this diagram of the ideal collision. The red box represents the starting position, the green box represents the proper position and the black box represents the static object it is colliding against. The blue arrow is the velocity vector. With my current implementation, the object would be placed in its final position and pushed out (and in this case it would be pushed left)    How can I fix this?


How do I read a resource file from a Java jar file?

I'm trying to access an XML file within a jar file, from a separate jar that's running as a desktop application.  I can get the URL to the file I need, but when I pass that to a FileReader (as a String) I get a FileNotFoundException saying "The file name, directory name, or volume label syntax is incorrect."  As a point of reference, I have no trouble reading image resources from the same jar, passing the URL to an ImageIcon constructor.  This seems to indicate that the method I'm using to get the URL is correct.  URL url = getClass().getResource("/xxx/xxx/xxx/services.xml"); ServicesLoader jsl = new ServicesLoader( url.toString() );   Inside the ServicesLoader class I have   XMLReader xr = XMLReaderFactory.createXMLReader(); xr.setContentHandler( this ); xr.setErrorHandler( this ); xr.parse( new InputSource( new FileReader( filename )));   What's wrong with using this technique to read the XML file?


Limit of sequence $n!\left(\frac{e}{n}\right)^n$

Find the limit of $$ \lim_{n\to +\infty} n!\left(\frac{e}{n}\right)^n. $$ I have shown that $u_{n+1}>u_n$, but I am not sure where to go from here.


why this vector space is not isomorphic to its double-dual

let $V$ be the vector space of all sequences of real numbers which are eventually $0$, that is $ V=\{s=(a_1,a_2, . . .) | \exists N$  such that $a_N = a_{N+1} = · · · = 0\}$.  We know the natural linear map $V → V''$ is not an isomorphism, where $V''$ is the double dual of $V$, but I am not sure why. Could someone explain this to me, thanks a lot!


I have an Ubuntu PC, and would like to copy some files to a windows PC. Before I do this, I would like to scan these files for malware, which works in windows.  Is there an Ubuntu virusscanner for windows viruses?  Thank you


How to find definite integral of $\sqrt{1-\sin x}$

I tried to solve this.But I end up with two types of antiderivative function.Then how to find the definite integral of this function? My results are -2(Sin x/2 -Cos x/2) and 2√(1+sinx).Which one should i use to find definite integral?


How do I get the output of a sub process and assign it to a variable. EG: assign the output of wmic csproduct get uuid returns a long string of characters in CMD, how would I run that command in C++ and assign it to a variable?


To give some background, I am currently a graduate student with a teaching assistantship and am teaching precalculus this semester. The department really pushes us to hammer the differences and similarities between degrees and radians and instances where you might use one over the other and so I am looking for some nice applications of both degrees and radians, but especially radians since most students are already comfortable with degrees. One of the main points the department likes us to make is that calculating arc length is much easier when working with radians as opposed to degrees, but I would like some additional examples.   I am at a larger state school and the audience is primarily first year college students or students taking math again for the first time in a couple of years, so ideally examples shouldn't be esoteric and require a lot of knowledge of mathematics; so things such as $$ \lim_{h \rightarrow 0} \frac{\sin(h)}{h} = 1$$ are not what I am looking for. Bonus points for examples where working with radians as opposed to degrees makes your life simpler.


My sister needs a camera. Can anyone guide me which one to buy, as I have no knowledge about it.  She is studying Architecture, and she often goes for site seeing and she needs to take picture(mainly buildings, structure, interior)  I asked some of my friends which camera will be good for her, they said  Point & Shoot will be good. There are many point and shoot cameras available in the market which one to buy? can some one give me some more specification or details, so that I can buy a good camera to my sis, from architectural view point.  Preferred brand- Nikon


How can I root my LG Optimus M MS690 on Metro PCS? I've tried Gingerbreak, Superoneclick, and z4root without luck.


An equivalent condition with $\{0\}$ being the only nilpotent ideal

In a ring $R$ prove that $\{0\}$ is the only nilpotent ideal if and only if for every ideals $A$ and $B$ from $R$, $AB=\{0\}$ implies $A\cap B=\{0\} $.


I am writing a technical letter for my (and my lab partner’s) senior design project (we are engineering majors) and I would like some help on properly phrasing part of the letter.  The project belongs to my partner and I. I was always taught in school that in cases of dual possession, I should always proceed the other possessors.   Suppose for a moment that the project was just mine. Then in that case, the sentence below would be grammatically correct.     Attached to this email is my project selection.   Now if the project only belonged to my partner, this sentence would also be grammatically correct.     Attached to this email is my partner's project selection.   However, since this project belongs to both of us, I need to phrase the sentence accordingly.  The sentence below doesn’t appear to be correct in my opinion.     Attached to this email is my partner and I's project selection.   This one sounds better, but doesn’t follow the rules I was taught.     Attached to this email is mine and my partner’s project selection.   So which phrase (if any) should I use to be grammatically correct? Thanks


Removing 180th meridian line on map of Russia?

I'm not sure how to remove the line that represents the 180th meridian (international dateline) on my polygon. I have the "Russia Country Boundary 2017" feature layer added from the Living Atlas. My Projected Coordinate System is set to "Asia North Albers Equal Area Conic". I've tried to google this question, but I haven't come across an answer I can fully understand. I'm a student and very new to all this!  The line is actually a gap between the polygons.   Using ArcGIS Pro 2.3.1  ANSWER:  It turns out I was not projecting correctly, which was creating issues down the line when editing polygons. Here's what I did...  1. Start a blank project in ArcGIS. Insert new map, go into its     properties, change the Coordinate System to "Asia North Albers Equal     Area Conic".  2. Add "World Countries (Generalized)" from the Living     Atlas. Select Russia and Export Features to new feature class layer.  3. Search and select the Project tool from Analysis>Geoprocessing>Tools.   4. Select the Russia layer for input. Select "Current Map" for Output Coordinate System. Run.  5.Now edit the polygons to close the gap and merge to remove any lines. All done!  The only thing that bothers me with this fix is the addition of shape area (484,914.49674 m²) and shape length (4.59 m) to the original Russia polygon. These numbers could be different depending on how you close the gap, and possibly affect data projections depending on your use of this map?


After setting the values for the fields of the first table, how do I fill out the fields of its child table?

I'm learning how to simply add records to a table with a child table using MS Access, please see the figure at the bottom. Below, c is just an instance of a class that I made where I set up the connection for the database.   public void addRecord(String name, String itemName){     long key = 0;     try {         c.openConnection();         String sql = "INSERT INTO custDetail ([custName]) VALUES('"+name+"')";         // After hopefully inserting the values to the fields of custDetail,         // I'm trying to get the custID from the newly inserted record         c.stmt.executeUpdate(sql, Statement.RETURN_GENERATED_KEYS);         c.rs = c.stmt.getGeneratedKeys();          if (c.rs != null && c.rs.next()){             key = c.rs.getLong(1);         }         c.closeConnection();          c.openConnection();         c.ps = c.con.prepareStatement("INSERT INTO rentDetail (custID, rentItemName)" + "VALUES (?, ?)");         c.ps.setString(1, String.valueOf(key));         c.ps.setString(2, itemName);         c.ps.executeQuery();         c.closeConnection();     } catch (SQLException ex) {         Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);     } }   Right now I'm getting this error:  Exception in thread "main" java.lang.NullPointerException at test.Test.addRecord(Test.java:34) at test.Test.<init>(Test.java:24) at test.Test.main(Test.java:16)   So I can't really see if it will work even if I got rid of that error. I'm just a beginner so I apologize if the code is beyond unpleasant, but I've been trying to figure this out for 5 hours now so I took the guts to post it here.    EDIT  Here's my complete code for NewConnection  public class NewConnection {     Connection con = null;     PreparedStatement ps = null;     ResultSet rs = null;     Statement stmt;      public void openConnection(){         String url = "C://Users//Lenovo//Documents//PROGRAMS//JAVA//Test//Test.accdb";         try{             Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");             String driver = "jdbc:ucanaccess://" + url;             con = DriverManager.getConnection(driver);         }         catch(SQLException ex){             System.out.println(ex);         } catch (ClassNotFoundException ex) {             Logger.getLogger(NewConnection.class.getName()).log(Level.SEVERE, null, ex);         }       }      public void closeConnection(){         try {             if (con != null)                 con.close();             if (ps != null)                 ps.close();             if (rs != null)                 rs.close();         }          catch (SQLException ex) {             Logger.getLogger(NewConnection.class.getName()).log(Level.SEVERE, null, ex);         }     } }


Maybe it is a ridiculous question but I want to know exactly what is an upstream program? here in  and other debian packaging documentation mentioned  upstream program.  I want a definition to create upstream from my application.  For example is my web application which is written in java is an upstream?


We define $A$ to be a finite set if there is a bijection between $A$ and a set of the form $\{0,\ldots,n-1\}$ for some $n\in\mathbb N$.  How can we prove that a subset of a finite set is finite? It is of course sufficient to show that for a subset of $\{0,\ldots,n-1\}$. But how do I do that?


GWT Remove URLs Tab has requests for removal I didn't put

I'm seeing in GWT a bunch of request of removal of pages, which weren't submitted from someone in my organization. I'm referring to the tab under Google Index->Remove URLs. Does it include any user-requested removals? How does someone submit such a request? It allows me to cancel a request (which I didn't submit in the first place) how does that make any sense?


Windows 10 brought new PATH environment variable editor, but for some reason, it just stopped working for me.   The odd thing is that path editor is "broken" only for system variables.. in case of User variables, the editor is fine.  System editor:    User Path editor:    As you can see, both are editing Path variable, however both use different editor. This is quite infuriating, have you ever encountered such error?


I created an array and gave tems 1 to 12 values. I did this to later loop through a part of code with each name. for some reason i get an error at my firs array fill line: "Object required". any ideas? And doe the rest of this code make sense too?                  Dim sArray() As String                 Dim row As Long                 Dim i As Long                 Dim arrTot() As Long                 Dim arrLate() As Long            'Error here                 Set sArray(1) = "AAA CANADA INC."                 Set sArray(2) = "AEROTEK ULC"                 Set sArray(3) = "AKKA GROUPE AMERIQUE DU NORD INC."                 Set sArray(4) = "ALTITUDE AEROSPACE INC."                 Set sArray(5) = "ASSYSTEM CANADA"                 Set sArray(6) = "BERLETEX AERO DESIGN"                 Set sArray(7) = "MSB DESIGN INC."                 Set sArray(8) = "NORAMTEC CONSULTANTS INC."                 Set sArray(9) = "SATYAM COMPUTER SERVICES LTD."                 Set sArray(10) = "T.E.S. CONTRACT SERVICES INC."                 Set sArray(11) = "TATA CONSULTANCY SERVICES CANADA IN"                 Set sArray(12) = "TDM TECHNICAL SERVICES"                  Set vendor = Range("P2:P" & lr)                 row = 1                 For Each cell In invoicedates                     For i = 1 To 12                         If tbl1(row, 16) = sArray(i) Then                             arrTot(i) = arrTot(i) + 1                             duedate = cell.Value + 60                             If Date > duedate Then                                 arrLate(i) = arrLate(i) + 1                             End If                         End If                     Next                     row = row + 1                 Next


Need to extend the validity (number of days) for an unused Schengen visa

I applied for a Schengen visa at the Swiss embassy and they gave me exactly 10 days for the dates of the application I submitted.    My husband (he's holding an american passport so he doesn't require any visa) now decides to extend our honeymoon for one more week.    They advised me to resubmit our application with the updated requirements (itineraries, tickets, etc.) They will have to cancel my original visa and issue another one (after evaluation).  Has anyone had a similar situation?  More info: I already have a previous Schengen visa with multiple entry and valid for 30 days stay.


Format external hard drive with ubuntu installed on it (for use as a Windows external)

I installed a new Windows hard-drive in my computer and took the old one (Ubuntu 14.04 installed on it) out and put this in an external hard drive encasing.  The problem I am facing now is that Windows does not pick this external hard drive up (the only way to use the hard drive is to switch the laptop off, plug the external in and boot into the Ubuntu OS installed on the external. How do I format this hard drive for use as a Windows external?


Merge two excel files using a common column

I have two excel sheets. I have to merge the two such that the values in one match with the other. For eg.  The first excel,    the 2nd excel  1  t                 1   tes1 2  5                 3   tes3 3  t                 4   tes4 4  g   Notice that in the first column of the 2nd excel, 2 is missing, so I want the first excel to look like this,  1 tes1 t 2      5  3 tes3 t 4 tes4 g   I am new to excel. Any help on this will be highly appreciated.


fatal error :"python.h" no file or directory?

While looking for a solution for the , I found .  I went through the readme.md file and I performed everything described there. After copying hungarian.so into my working directory, when I tried to compile hungarian.cpp using make hungarian, I got this output:  anupam@JAZZ:~/Python/hungarian-master$ make hungarian g++     hungarian.cpp   -o hungarian hungarian.cpp:7:20: fatal error: Python.h: No such file or directory  #include "Python.h"                     ^ compilation terminated. make: *** [hungarian] Error 1   I found , but the answer didn't work for me.  I am very new to GitHub I don't know how to add modules on g++. Can someone help me with that, and what to do next?


Prevent Windows 7 users from canceling shutdown (disable shutdown -a)

From Windows 7 admin account I've set up a scheduled task with max privileges that executes a .cmd file which executes  shutdown -s -f -t 120   if the user happens to be logged in and its past their allowed hours.  The user has only user rights but he still can cancel my Admin enforced shutdown by typing in Run box  shutdown -a.    How do I prevent user from canceling and Admin issued shutdown? UAC is enabled. Thanks.  My final .cmd is this:  @echo off for /f "delims=" %%? in ('tasklist /v^| findstr /B /C:"explorer.exe"') do call :USERis %%? :USERis echo/%*|find "username">nul 2>&1&&(set "liet=username") echo/%*|find "Administrator">nul 2>&1&&(set "liet=Administrator") echo/%liet% if %liet%==username ( msg /server:localhost * /time:120 "Computer is shutting down in 2 minutes!" timeout /T 120 shutdown -s -f -t 0 -c "Computer is shutting down!" ) else ( echo Admin logged in! echo Do nothing exit ) exit  It is scheduled to run repeatedly every 3 minutes during 8 hour period when the PC should be off limits for user. So even if the PC is restarted it still gets a shutdown if User is logged in. Bios has setup password, time & date cannot be changed from user profile. Didn't check if BIOS boot menu works (to boot Linux and change time). Users are Linux dumb though.


If $\left|z+\frac{2}{z}\right |=2$, then prove that max value of $|z|$ is $\sqrt 3 + 1$

Solving the quadratic inequality   $$|z|\ge1+i$$ and $$|z|\le1-i$$  I don’t know how to solve further. Please help  Thanks!


I have a .png screenshot and I want to insert it in a  LyX document.    However, the screenshot needs scaling to fit in my column width. Downscaling (or upscaling) the image, if done wrong, gives all kinds of bad, unprofessional results.  How do you embed screenshots properly? Is there a way to change the interpolation mode, or disable it altogether (and does it acually help)?


Disabling Lock Screen Fade to Black on Ubuntu 17.10 (Wayland)

When I lock the screen with the shortcut or      gnome-screensaver-command -l  The screen locks then sleeps, putting my monitor to sleep, I can't seem to be able to make any xorg workarounds work in Wayland (Obviously)  Is there a way to disable this functionality? It is really annoying.


Where should I ask about which platform to use for an embedded controller application?

I tried posting this on Stack Overflow and was told hardware questions are not allowed (yet, most Arduino hits on Stack Exchange are at Stack Overflow). Is there a site where I can ask this question?  I need help choosing hardware, language, and IDE for an application that requires more computing power than an Arduino provides. Because of the nature of the team, it would be great if it were as easy to use as Arduino. Essential hardware features are:  interrupts, UART, SPI, and about 10 GPIO.  The code will use:  signed 32-bit numbers but it does not require floating-point support. Probably not more than 1000 lines of code if in C. The application is a high-resolution multi-channel PID controller with a simple command parser so it can be controlled by text commands via the UART. We prefer a bare-metal implementation. RTOS is not required. The board should be small and < $20 in quantities of 100. Open source is always better. Low power is not important. It should be programmable through the UART or USB.  So what are some good options to look at? There are no language restrictions. C might work but we are open to other options, for example MicroPython or eLua.


mobile comments space stops working at line end

I noticed this a while ago, but only now I realized the pattern and can tell when it's happening.   When commenting using mobile version, if reaching a line-break, i.e. the next word will be on a new line, pressing space doesn't work. You can press as many times as you want, you just stay in place, at the end of the last word.  The workaround is writing the next word  (or first character) right after the last word (so they are joined), manually going back in between them and then pressing space, which is tedious and annoying  I'm using a Galaxy S I, using default browser, haven't tested behaviour on others.


Could someone please tell me what I'm doing wrong with this code? It is just printing 'count' anyway.  I just want a very simple prime generator (nothing fancy).   import math  def main():     count = 3     one = 1     while one == 1:         for x in range(2, int(math.sqrt(count) + 1)):             if count % x == 0:                  continue             if count % x != 0:                 print count          count += 1


Are some weaker attacks better due to speed and less power up required to use them? For instance a 50 attack with 2 short power up bars compared to a 60 attack with one long power up bar. Anyone have any insight here?


Did the Obliviate-in-the-rain spell with the Thunderbird at the end of Fantastic Beasts affect those who were indoors?

Did the Thunderbird and rain and Obliviate spell at the end of Fantastic Beasts affect everyone in New York City? Or just those who were standing in the rain?  This video seems to imply anybody who was indoors was also affected, but I would prefer an explanation from a canon source.                                  If the Thunderbird's rainstorm was the key to spreading the Obliviate spell across the entire city, I don't see how that would affect people indoors. Or maybe not even those under an umbrella.  Hmmm, maybe that is why Queenie made a magical umbrella when she kissed Jacob as she obliviated his memories. Perhaps that's why he seems to remember some details.                                  An answer to a related question says,     The rain water contaminates the water in the pipelines and/or overhead storage tanks of the buildings in the city. As you mentioned, a guy in the shower loses his memory. There is also a shot of a woman drinking from a tap who also loses her memory. (emphasis mine)   So if the rainwater is the key to the forgetfulness, then what about all the people who were indoors and did not sip water that day?


How to open files from folders using terminal command

I am beginning to learn and love ubuntu.  Is there any way to open files like .pdf, .jpeg, .odt, .docx etc. using command line?  For instance, I have a pdf named: 9949107741MathFormulas.pdf in the following directory:  jitendra@jitendra:~/Downloads/Math.Formulas.and.Tables.8.Retail$   when I go to above directory type 9949107741MathFormulas.pdf to open it, I get the message:  9949107741MathFormulas.pdf: command not found   Please advise, how can this task be accomplished?


Why we should say North and South City instead of South and North City??


If I have created a class like this:  struct test{   int a;   int b;   string c; };   and wanted to iterate through each data member as if it was an array how could i do it?(Assuming the number of members may change in a future update.)


What happened with Hilbert's sixth problem (the axiomatization of physics) after Gödel's work?

I'll write the question but I'm not fully confident of the premises I'm making here. I'm sorry if my proposal is too silly.   consisted roughly about finding axioms for physics (and it was proposed in $1900$). I guess that at the time, such thing was impossible due to the nature of physics which is mainly based on observations and models. But it seems that after Gödel's work on $1931$, the axioms which were seen as self-evident truths started to be seen as unprovable statements and the job of a mathematician is grossly about deriving theorems from these axioms.  So if this shift of axiomatic conception really happened, couldn't we just accept anything (including the physical observations) as axioms and reason about their consequences? Thus somehow solving Hilbert's sixth problem?


Comment character counter does not trim, while the server does

In the comment field on StackOverflow (and other StackExchange sites as well, I presume) you're required to write 15 characters for the server to accept your post. If a shorter post is submitted, an information message states that the comment is too short. That is all good.  However, below the comment field is a counter, which counts up to 15 and then down from however many characters you're allowed to type minus fifteen. This counter doesn't always act the same as the actual validation: if I pad my message with whitespace, the validation notices and still says the message is too short, but the counter does not notice, and counts as usual.  Suggested fix: make the character counter trim the message before it counts, so the two messages say the same thing.


No. of ways in which n letters can be put in n envelopes such that none is in the right one         I have tried a few approaches but I can't figure out the logic.        One approach:       No. of possible envelopes for the 1st letter=(n-1) No. of possible envelopes for the 2nd letter=(n-1) in case previous letter was inserted in 2nd envelope, or, (n-2) in all other cases and so on.       But this doesn't seem to be the right way.  Another way is to count the no. of ways in which all or some are in the wrong place and then subtracting from total combinations. No of permutations with 0 in wrong place=1 No of permutations with 1 in wrong place=1 No of permutations with 2 in wrong place=2 . . .  But I can't figure out the pattern.       I need help in solving this question


$\mathrm{rank}(AB-BA)=1$ implies $A$ and $B$ are simultaneously triangularisable

Let $A$ and $B$ in $M_n(\mathbb C)$ such that the rank of $AB-BA$ is $1$. Prove that $A$ and $B$ are simultaneously triangularisable.  This generalizes the classical case $AB = BA$. By induction on $n$, it suffices to show that $A$ and $B$ have a common eigenvector. So, it would be sufficient to find a eigenspace of $A$ which is stable by $B$ since matrices are complex. Do you have ideas for that? Thank you.


prove this properties of triangles trigonometric question

The triangle $DEF$ circumscribes the three escribed circles of triangle $ABC$.  Prove that  $$\frac{EF}{a\,\cos A} = \frac{FD}{b\,\cos B} = \frac{DE}{c\,\cos C}$$


Is there a specific word for adult offspring? If all of your "children" are now in their adulthood, is there a specific word to refer to them?


Self descript. I know it's already been asked  and . But apparently it's still an issue. This only started happening to me this week that I've noticed. Per the comments in the linked answer, a hard refresh should fix it but alas, it does not. Firefox 57.0. Works on SE but doesn't work on SO or many of the other sites I visit.   I disabled my add-ons and did a hard refresh but still to no avail. I've exited my browser cleared my temp stuffs as well.


How can I open and reset the combination lock on my suitcase, I have forgotten the combination

How can I reset the combination and open my suitcase? I have forgotten the origanal combination.


Are there non-magical people born into magical families?

Is there any case in the Harry Potter-verse of someone magic born but having no magic skills? I haven't read enough to know why muggleborns can have magic powers but if it works one way then maybe the other?


Why does this pattern occur: $123456789 \times 8 + 9 = 987654321$

I came across the following:  $\begin{align} 1 \times 8 + 1 &= 9 \\ 12 \times 8 + 2 & = 98 \\ 123 \times 8 + 3 & = 987 \\ 1234 \times 8 + 4 & = 9876 \\ 12345 \times 8 + 5 & = 98765 \\ 123456 \times 8 + 6 & = 987654 \\ 1234567 \times 8 + 7 & = 9876543 \\ 12345678 \times 8 + 8 & = 98765432 \\ 123456789 \times 8 + 9 & = 987654321. \\ \end{align}$  I'm looking for an explanation for this pattern.  I suspect that there is some connection to the series $\frac{1}{(1 - x)^2} = 1 + 2x + 3x^2 + \cdots$.     asks the same question but has no answers posted.


Consider these two variations:   Every morning, tourists can see soldiers raise the national flag in the square. Every morning, tourists can see soldiers raising the national flag in the square.   What are the differences?  Which sounds more natural?


Wordpress + postfix + unsolicited emails being sent even if the email account wasn't created

I run a blog on wordpress. Recently I received a abuse complaints from the server which when verified returned this:  ============================================================  Received: from [192.241.188.154] by usfamily.net  (USFamily MTA v5/:PG5vcm1hX2NoYW1iZXJzQG1yaW5hbHB1cm9oaXQuY29tPjxkamtpbm5leUB1c2ZhbWlseS5uZXQ_) with SMTP id <20140301115044001084500013> for <djkinney@usfamily.net>;  Sat, 01 Mar 2014 11:50:44 -0600 (CST)  (envelope-from norma_chambers@myblog.com, notifiable emailnetwork 192.241.188.)  Received: by myprimarydomain.com (Postfix, from userid 498)  id 1C5EE1305AE; Sat, 1 Mar 2014 17:12:39 +0000 (UTC)  To: djkinney@usfamily.net  Subject: FW: Good day  X-PHP-Originating-Script: 498:sslnEn.php  From: "Norma Chambers" <norma_chambers@myblog.com>  Reply-To: "Norma Chambers" <norma_chambers@myblog.com>  X-Priority: 3 (Normal)  MIME-Version: 1.0  Content-Type: text/html; charset="iso-8859-1"  Message-Id: <20140301171239.1C5EE1305AE@myblog.com>  Date: Sat, 1 Mar 2014 17:12:39 +0000 (UTC)  Content-Transfer-Encoding: quoted-printable

  Top Meds Website good deal http://dumantarim.com/modules/mod_araticlhess/rlf.h=  tml

  ============================================================   Now I assumed that it meant this: Several unsolicited emails were sent from the id norma_chambers@myblog.com. If my assumption is correct, this email id should have existed on the VPS AND user had access to the email account to send mails. Does it really means that my server (VPS) was hacked? I am not actually using any contact form on my blog as such but this may be caused by any plugin etc.??? Not sure :(  Am I on the correct path to trace this problem? Please shed some light.


When to rebuild and when to reorganize indexes

I have been trying to gather information about rebuilding and reorganizing indexes. From stackoverflow page (How Often should the indexes be re-build in sql-server DB?) i got this query :  SELECT      t.NAME 'Table name',     i.NAME 'Index name',     ips.index_type_desc,     ips.alloc_unit_type_desc,     ips.index_depth,     ips.index_level,     ips.avg_fragmentation_in_percent,     ips.fragment_count,     ips.avg_fragment_size_in_pages,     ips.page_count,     ips.avg_page_space_used_in_percent,     ips.record_count,     ips.ghost_record_count,     ips.Version_ghost_record_count,     ips.min_record_size_in_bytes,     ips.max_record_size_in_bytes,     ips.avg_record_size_in_bytes,     ips.forwarded_record_count FROM      sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'DETAILED') ips INNER JOIN       sys.tables t ON ips.OBJECT_ID = t.Object_ID INNER JOIN       sys.indexes i ON ips.index_id = i.index_id AND ips.OBJECT_ID = i.object_id WHERE     AVG_FRAGMENTATION_IN_PERCENT > 0.0   ORDER BY     AVG_FRAGMENTATION_IN_PERCENT, fragment_count   The problem is that when i rebuilt indexes the avg_fragmentation_in_percent increased instead of decreasing. Any pointers?? If this is the normal behavior then what am i missing here??  Previously the avg_fragmentation_in_percent was 30 and after rebuild it has increased to 66.


Lost space after removing bootcamp partition via bootcamp assistant

please help  i lost 150gb space after deleting the partition via boot camp assistant and the disk utility won't recover it or partition it as one disk  i tried to recover by timemachine but the disk looked the same size and iam afraid the restore wont get the space back


I am doing some reverse engineering and want to know which APIs are called from the executable.  I am mostly interested in the APIs called on a particular Windows system DLL.  I guess one way to do that is to get all APIs exposed from the DLL using dumpbin and put breakpoints on all those from Windbg.  Any other approach? This seems like lot of time if I need to monitor many system DLLs.  BTW, I am working on Windows XP and want to monitor one executable which calls some Windows system DLL functions.


Looking for a book series about a girl and her friends captured and sold as slaves

I'm trying to find the name of a book series I read about 10 years ago. It might be a children/young-adult series since I was fairly young. There is also a small chance it was written by a french author, as I read it in french. The series is composed of at least three books, maybe more. Here is what I remember :   The main character is a poor girl/young woman, but there are several point of view characters At the beginning of the first book the plot is set in a city where rich people live in the city center and the further you go from the center the poorest people are. Moreover, the houses are painted according to the wealth of the owner. It was something like : the richer had red houses, the poorer blue houses, and the moderately wealthy purple (it was not those colors in particular but it was something like that) At the end of one of the book there is some kind of uprising and the people paint all the houses in multiple colorful shades (to symbolize the new found equality between the citizen) At some point the main character and other peoples of the city get captured (maybe after some kind of war the city was involved in), separated and sold to slavery One of them, an older boy, become a soldier and learn a special fighting technique that looks like dancing (and he grows to like it) Another of the captives, a young girl (the sister of the main character if I recall correctly) get marked with a fire-heated mark to show her condition of slave   That is all I remember, I have no clue about the time or geographic setting nor the story details.  I know it's not much to go by, any help would be greatly appreciated, as I would like to find these books and read them again.


Invariance property of MLE: what is the MLE of $\theta^2$ of normal, $\bar{X}^2$?

Invariance property of MLE:  if $\hat{\theta}$ is the MLE of $\theta$, then for any function $f(\theta)$, the MLE of $f(\theta)$ is $f(\hat{\theta})$.    Also, $f$ must be a one-to-one function.  The book says, "For example, to estimate ${\theta}^2$, the square of a normal mean, the mapping is not one-to-one."  So, we can't use invariance property.  But then, it proves the property and says, "we now see that MLE of $\theta^2$, the square of a normal mean is $\bar{x}^2$".  This seems self-contradicting, we are squaring $\bar{x}$, but square of anything is not one-to-one, what am I reading wrong here?  Thanks!  source: Casella & Berger "Statistical Inference"


Session in a limbo state - Killed/Rollback

I have a SQLjob that calls xp_cmdshell that is used to dump a txt file to an ftp site via a script.  At times it fails and the job gets hung up in an executable state. Generally I would kill the session and it gets cleared.  However, I have two sessions that are hung in a limbo state.   sp_WHO2 53 -- running from 7/8/2018     SP_WHO2 98 -- running from 6/16/2018     The job status says its Runnable but the Command is KILLED/ROLLBACK.  Checking SPID 53  Kill 53 with status only    Output   SPID 53: transaction rollback in progress. Estimated rollback completion: 0%. Estimated time remaining: 0 seconds.    Checking SPID 98  KILL 98 with status only   Output   SPID 98: transaction rollback in progress. Estimated rollback completion: 0%. Estimated time remaining: 0 seconds.    How do I go about clearing these sessions?  I am having performance issues with the SQL Server, which led me to these sessions. I did some research and points me to believe that it will increase the log files and cause performance issues. I am unaware if the current issue is because of these sessions but they are active expensive queries. So I thought of starting from here. I am developer here and I am aware that activity monitor is obsolete in SQL SERVER 2014 But i did check activity monitor and below are the images.      Can you suggest how I can go about it?   I did read a blog about such a scenario by Brent Ozar - .   Learnt the hard way, looking into fixing the root cause.  AK


Dual boot Ubuntu 16.04/Windows 10 no longer booting

I'm running Ubuntu 16.04 and Windows 10 on 2 separate hard drives (no partitions, 2 physical hard drives).  Two things have happened:   I no longer get the GRUB boot loader screen which allows me to choose which operating system I boot into (I recall that this used to work under a similar setting running Linux Mint 15 and Windows 7) Suddenly Windows 10 won't boot anymore. Even though I set it as the first drive to boot from in the BIOS.    What am I doing wrong here? I've seen some stuff about installing ubuntu in uefi mode. Is that something I need to consider? I am fairly new to Ubuntu and a complete noob when it comes to setting up partitions, etc.  Thank you,  BR  Johan


When to use If-else if-else over switch statements and vice versa

Why you would want to use a switch block over a series of if statements?  switch statements seem to do the same thing but take longer to type.


What's the term to designate the absence of bureaucracy?

I am searching a term which means: absence of forms, bureaucracy and long procedures. I don't know if formless could be correct as long as it is a neologism.


Consider the following function:  $\displaystyle f(x) = \frac{x^2-4}{x-2}$  and now its limit:  $\displaystyle \lim \atop x \to 2$ $\displaystyle \frac{x^2-4}{x-2}$  Upon evaluating, this limit becomes:  $\displaystyle \lim \atop x\to 2$ $\displaystyle x+2 = 4$  The limit therefore exists since it meets each of the following criteria:  The limit approaches a finite value ($4$), the limits on either side of $x=2$ correspond and the limit approaches a particular value ($4$)  With this in mind, does that mean that $\displaystyle \lim_{x\to 0}\frac{1}{x}$ does not exist? Seeing as it does not approach a finite value?


Adding ECW support in GeoServer OpenGeo Suite?

I have installed opengeo suite 4.8 with GeoServer:   " 2.8-SNAPSHOT   Git Revision5ba955074e0c5b78a5c9576dba955bec93008889   Build Date14-Jan-2016 20:47   GeoTools Version14-SNAPSHOT (rev 109456cbb2cf31ce318330bad5d0176e3d04e4a9)    GeoWebCache Version1.8-SNAPSHOT (rev 1.8.x/854b89c13d79df5a232c32245f956cfb70de56f5) "  I am trying to add ECW support to this version of geoserver but no luck; don't know where can i download the right plugin, and don't know if that is possible on this version of geoserver. I would like to add other plugins if its possible in this version.


Does the "for…in" loop in Javascript loop through the hashtables/elements in the order they are declared? Is there a browser which doesn't do it in order? The object I wish to use will be declared once and will never be modified.  Suppose I have:  var myObject = { A: "Hello", B: "World" };   And I further use them in:  for (var item in myObject) alert(item + " : " + myObject[item]);   Can I expect 'A : "Hello"' to always come before 'B : "World"' in most decent browsers?


How to fix the black screen issue before installing Ubuntu16

I want to install dual systems through USB flash disk, win10+ubuntu16, and now win10 is ok, then I try to install ubuntu16, just like the image show, there are maybe some problem with my graphics card on ubuntu, and I have search a lot, still can not fix this prob.  my Graphics Card is 'GTX 1070'  select 'Install Ubuntu'   then I got this


Why does the Pythagorean theorem involve squares rather than any other powers?

Is there a common property of spaces, where one squares coordinates to obtain distance (such as Euclidean, Minkowski spaces), responsible for this choice of power (i.e. 2)?


I don't know, how should I start solving this: $$a_1 = 2 \\ a_n = 2a_{n-1} +7$$ using the repertoire method.  Could anyone give me an algorithm or explain, how to use this method in this case?


I am trying to figure out how I can prove that there exits $a\in R$ such that $a^3=2$ using the completeness axiom ?  I know that the completeness axiom for the real numbers states that for every non empty set $S$ which is bounded above, then the supremum of $S$ exists.So in the above example, would the supremum be equal to $2$ ?  How do I go about proving the above using the completeness axiom ? Could someone provide a proof for this problem ?


G is a group and N a subgroup of G, and if index of N in G is 2, then N is Normal. Can someone please explain why?


I've been trying to save up my money to buy the illegal gun parts, but their cost is 75 gold coins. Can someone please tell me how to easily get them? Thanks.


If $Y=F(X)$ is $U[0,1]$ where $F$ is cdf of continuous $X$ then shouldn't its plot be rectangular?

I understand the analytical proof given here.     But in that case since $Y=F(X)$, say where $F(X)$ is the cdf of a standard normal distribution $N(0,1)$ the plot of which is not rectangular but rather S shaped.  I fail to understand. Could someone please help?


"currently running survey" or "currently-running survey"?

I still struggle to understand exactly when to use hyphens when adverbs are involved.  Which of the following is correct? ABC is an acronym representing the actual name of the survey.  "I use results from the currently running ABC survey."  "I use results from the currently-running ABC survey."


Probability that the man is the first to die

If p is the probability that a man aged x will die in a year then the   probability that out of n men $A_1, A_2 ,A_3 ...A_n$, each aged x,   $A_1$ will die in an year and be the first to die is: ?      a) $1- (1- p)^{n-1}$       b)$(1-p)^n$      c) $\dfrac 1n [1- (1-p)^n]$      d) $\dfrac 1n (1-p)^n$   Attempt:   Order of dying matters.   Choose $r$  out of $n-1$ and arrange them (i.e. their deaths) in $r!$ ways.   So $P(E)  = p\times{^{n-1}C_0} (1- p)^{n-1}+ p \times p\times {^{n-1}C_1} (1-p)^{n-1} + p\times p^2 \times 2!\times {^{n-1}C_2} (1- p)^{n-2}+...$  $\implies P(E) = p \sum_{r=0}^{n-1} {^{n-1}}C_r (1-p)^{n-1-r}p^r \times r!$  But this doesn't match any of the options.   Could someone please tell me where I have gone wrong?   Edit: My prime focus is the mistake that I have made in solving which that question doesn't cover. therefore, please don't mark it as a duplicate


How can I write the following mathematical formula with arrows?

How can I wrote this unseen (for me) arrows in LaTeX?


Remittance of gift money from Indian bank account to UK bank account

I was born in India and came to the UK 11 years ago when I was 20 years old. I'm a British Citizen and hold a UK bank account.   I also have an Indian bank account which is managed by my father in India. Up until now, we haven't transferred any money from my Indian bank account to my UK bank account.   My Grandmother is intending to gift me some money in my Indian bank account.   Would I incur any taxation for this Gift in UK? Does it change if I transferred that gifted money into my UK bank account and used it towards a house deposit here in the UK?


How do we show that this identity holds for any n? Any hints or solutions?  Show $\sum_{ r = 0}^{n} {(\binom n r)}^{2} = \frac{(2n)!}{(n!)^{2}}$


I suspect the answer to this is going to be "no", however, just in case anyone knows something...  I need to broaden the emission peak of a near IR LED. Is there any generally applicable method of doing this in a reliable manner?


What rules determine the apostrophe placement in "ham 'n eggs" and similar expressions?

In expressions such as "ham 'n eggs", the conjunction 'n appears to replace and, yet there is only one apostrophe to indicate the missing a and none for the missing d (i.e., no "ham 'n' eggs").    Is there a punctuation rule that governs this or is it just an idiosyncratic case?


Possible Duplicate:                How to prove that isometry $f:X\to X$ is onto if $X$ is compact??  What about the case when $X$ is non-compact?  Any help would be appreciated.


Consider a Lagrangian $L(x,\dot x,t)$ and a corresponding Hamiltonian $H=\dot xp-L$ where $p=\partial L/\partial \dot x$ which satisfies Hamilton's equations $$\frac{\partial H}{\partial x}=-\dot p$$ $$\frac{\partial H}{\partial p}=\dot x.$$ I'm trying to show that Hamilton's equations are unchanged by a gauge transformation of the Lagrangian $L'=L+ \frac{dF}{dt}$ where $F(x,t)$ is a function of the position and time only. I first expand the derivative of $F$ $$\frac{dF}{dt}=\frac{\partial F}{\partial t}+ \frac{\partial F}{\partial x}\dot x$$ the new conjugate momentum is $$p'=\frac{\partial L'}{\partial \dot x}=\frac{\partial L}{\partial \dot x}+\frac{\partial}{\partial \dot x} \frac{dF}{dt}=p+ \frac{\partial F}{\partial x}$$ and so $$\frac{\partial}{\partial p'}= \frac{\partial p}{\partial p'} \frac{\partial}{\partial p}=\frac{\partial}{\partial p}$$ The new Hamiltonian is $$H'=p'\dot x-L' = p \dot x-L+\frac{\partial F}{\partial x} \dot x - \frac{dF}{dt}=H- \frac{\partial F}{\partial t}$$ Hamilton's equations are then $$\frac{\partial H'}{\partial p'}=\frac{\partial H}{\partial p}- \frac{\partial}{\partial p} \frac{\partial F}{\partial t}=\dot x-0=\dot x$$ and $$\frac{\partial H'}{\partial x}=\frac{\partial H}{\partial x}- \frac{\partial}{\partial x} \frac{\partial F}{\partial t}= -\dot p-\frac{\partial }{\partial t} \frac{\partial F}{\partial x}$$ It is this last equation where I'm having trouble. To satisfy Hamilton's equations, the right side should be equal to $\dot p'= \frac{d}{dt}(p+\frac{\partial F}{\partial x})$ however I end up with a partial derivative on the last term rather than a total derivative as it should be. How can one justify this as satisfying Hamilton's equations?  Edit  It seems that the error is arising when taking the partial of $H'$. When applying $\partial/\partial x$ to $H'(x,p')$ we are implicitly holding $p'$ constant, where as $\partial H/\partial x=- \dot p$ is true only when we are holding $p$ constant, not $p'$. A workaround is to use the form $H'=p' \dot x-L'$ as the functional dependence is clear. Then $$\frac{\partial H'}{\partial x}= -\frac{\partial L'}{\partial x} = -\frac{\partial L}{\partial x}- \frac{\partial}{\partial x} \frac{d F}{dt}= -\frac{d}{dt} \left( \frac{\partial L}{\partial \dot x} + \frac{\partial F}{\partial x}\right) = -\dot p'$$ where Euler-Lagrange was used on the second last equality. I'm still unsure of how to apply the chain rule to my original expression to get the correct result.


HP LaserJet Pro m15w Isn't recognized (also with USB)

When installing HPLIP latest version it keeps writing this message, when trying to install manually the python "missing" packages it says they are already installed.   Tried so many solutions here - none worked :((   screen shows :   Distro set to Ubuntu 16.04  Initializing. Please wait...   ENTER ROOT/SUPERUSER PASSWORD ----------------------------- Please enter the root/superuser password:    SECURITY PACKAGES ----------------- AppArmor is installed.  AppArmor protects the application from external intrusion attempts making the application secure  Would you like to have this installer install the hplip specific policy/profile (y=yes*, n=no, q=quit) ? y   RUNNING PRE-INSTALL COMMANDS ---------------------------- OK   MISSING DEPENDENCIES -------------------- Following dependencies are not installed. HPLIP will not work if all REQUIRED dependencies are not installed and some of the HPLIP features will not work if OPTIONAL dependencies are not installed. Package-Name         Component            Required/Optional    python3-notify2      gui_qt5              OPTIONAL             python3-pyqt4-dbus   gui_qt4              OPTIONAL             python3-pyqt4        gui_qt4              REQUIRED             python3-pyqt5-dbus   gui_qt5              OPTIONAL             python3-pyqt5        gui_qt5              REQUIRED             python3-dbus         fax                  REQUIRED             python3-reportlab    fax                  OPTIONAL             Do you want to install these missing dependencies (y=yes*, n=no, q=quit) ? n error: Installation can not continue because all REQUIRED dependencies are not installed.


Meaning of a stack overflow in C programming

Here is the code below:  #include <stdio.h>  int main() {   printf("Stack Overflow");   main(); }   After compiling and executing this program it will print "Stack Overflow" until its stack overflows. Here, I know what a stack overflow means, that means it will print until memory is full. My question is which memory is it? What is the size of the stack that is overflowing?


How do I choose a ferite bead for power supply filtering?

I want to put a ferite bead on positive SMPS supply rail that goes to analog part of the mixed digital/analog circuit.   Now on parametric search at Digikey I can see several parameters: Current rating, DC resistance, Impedance @ frequency. I understand current rating and dc resistance, I understand impedance, but how do I make my choice - should I look for the greatest impedance @ 100MHz with acceptable DC resistance and current ratings for my application?


Why does the Causal Impact Analysis uses Bayesian Structural Time Series Model?

So, I have been studying causality and came across with Googles Causality Impact Analysis.  I already read the paper and watched Kay's keynote. However, I wonder if it is also possible to use a simple regression or a machine learning model build the synthetic post intervention series.


I am newbie in JavaScripts and I can say bash script easier than this. I want get json file from url then parse to get id list. I use mobile firefox on android. In bash script you write curl "your url" | jq '.id' . Then you get id from json file. Here is my code  // ==UserScript== // @name qwerty // @namespace http://use.i.E.your.homepage/ // @version 0.1 // @description enter something useful // @match http*://* // @grant        GM_xmlhttpRequest // @require http://code.jquery.com/jquery-3.4.1.min.js // @copyright 2012+, You // ==/UserScript==  //Test if script not work var b = "asdf" alert(b) alert(11);  //Script gets file from json url GM_xmlhttpRequest({   method: "GET",   url: "your url to json",    onload: processJSON_Response });   //Site response test function processJSON_Response(rspObj) {   if (rspObj.status != 200 && rspObj.status != 304) {     reportAJAX_Error(rspObj);     return;   }   //Alert to check response is correct or no   alert(rspObj.response)   var a = rspObj.response   //This code not work. It's json parsing   var id = a.id   //Alert id list of json   alert(id) }   Test json file  {"updated_at":"2020-04-27T18:52:13.107-04:00","id":[637,677,5765,202]}


Pulseaudio as system-wide systemd service

I want to run Pulseaudio system wide, on a headless CentOS 7 server.  Pulseaudio works great if I startx but in text mode (runlevel 3 equivalent) pulse audio clients fail.  So I created a systemd service file:  [Unit] Description=PulseAudio Daemon  [Install] WantedBy=multi-user.target  [Service] Type=simple PrivateTmp=true ExecStart=/usr/bin/pulseaudio --system --realtime --disallow-exit --no-cpu-limit    which starts, but I see the following in journalctl:  Jan 19 13:31:47 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] main.c: Running in system mode, but --disallow-module-loading not set! Jan 19 13:31:47 lserver.mydomain pulseaudio[2523]: N: [pulseaudio] main.c: Running in system mode, forcibly disabling SHM mode! Jan 19 13:31:47 lserver.mydomain pulseaudio[2523]: N: [pulseaudio] main.c: Running in system mode, forcibly disabling exit idle time! Jan 19 13:31:47 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] main.c: OK, so you are running PA in system mode. Please note that you most likely shouldn't be doing that. Jan 19 13:31:47 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] main.c: If you do it nonetheless then it's your own fault if things don't work as expected. Jan 19 13:31:47 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] main.c: Please read http://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/WhatIsWrongWithSystemWide/ for an explanation why system mode is usually a bad idea. Jan 19 13:31:48 lserver.mydomain pulseaudio[2523]: N: [pulseaudio] alsa-util.c: Disabling timer-based scheduling because running inside a VM. Jan 19 13:31:48 lserver.mydomain pulseaudio[2523]: N: [pulseaudio] alsa-util.c: Disabling timer-based scheduling because running inside a VM. Jan 19 13:31:48 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] authkey.c: Failed to open cookie file '/var/run/pulse/.config/pulse/cookie': No such file or directory Jan 19 13:31:48 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] authkey.c: Failed to load authentication key '/var/run/pulse/.config/pulse/cookie': No such file or directory Jan 19 13:31:48 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] authkey.c: Failed to open cookie file '/var/run/pulse/.pulse-cookie': No such file or directory Jan 19 13:31:48 lserver.mydomain pulseaudio[2523]: W: [pulseaudio] authkey.c: Failed to load authentication key '/var/run/pulse/.pulse-cookie': No such file or directory Jan 19 13:31:48 lserver.mydomain systemd[1]: Got message type=signal sender=org.freedesktop.DBus destination=n/a object=/org/freedesktop/DBus interface=org.freedesktop.DBus member=NameOwnerChanged cookie=56 reply_cookie=0 error=n/a Jan 19 13:31:48 lserver.mydomain systemd-logind[575]: Got message type=signal sender=org.freedesktop.DBus destination=n/a object=/org/freedesktop/DBus interface=org.freedesktop.DBus member=NameOwnerChanged cookie=56 reply_cookie=0 error=n/a Jan 19 13:31:48 lserver.mydomain systemd-logind[575]: Got message type=signal sender=org.freedesktop.DBus destination=n/a object=/org/freedesktop/DBus interface=org.freedesktop.DBus member=NameOwnerChanged cookie=57 reply_cookie=0 error=n/a Jan 19 13:31:48 lserver.mydomain systemd[1]: Got message type=signal sender=org.freedesktop.DBus destination=n/a object=/org/freedesktop/DBus interface=org.freedesktop.DBus member=NameOwnerChanged cookie=57 reply_cookie=0 error=n/a   and attempts to access audio fail:  speaker-test 1.1.1  Playback device is default Stream parameters are 48000Hz, S16_LE, 1 channels Using 16 octaves of pink noise ALSA lib pulse.c:243:(pulse_connect) PulseAudio: Unable to connect: Access denied  Playback open error: -111,Connection refused   And after speaker-test the log shows:  Jan 19 14:06:39 lserver.ocg.ca pulseaudio[2795]: W: [pulseaudio] protocol-native.c: Denied access to client with invalid authentication data.   User root is added to the 'audio' group.  And speaker-test is being run as root. Can someone suggest how to fix this?


I'm just looking for ideas for this. Say we want to predict the presence of a certain "thing" in a country by each postcode - let's take the UK, so there could be around 1.7 million postcodes - and you want to build a model where for each postcode, you're outputting either a 1 or a 0. A constraint could be the "thing" has uptake in 400k postcodes. You can imagine typical demographic data for predictor variables: population, income data, age range... However I feel independence between the outputs is too strong of an assumption - or at least, I'd like to this before applying models that assume it. I'm not really sure where to start so perhaps someone could give me some guidance - It wouldn't quite be logistic regression since the output variable would have some spatial correlation. There's also possibly enough training data with this large a set of postcodes - the model could be built using post sectors first, perhaps, but we'd still like a level of spatial correlation included... Any ideas or food for thought welcome, I'm kind of stumbling around in the dark so far. Am I right for instance in saying that multivariate regression would not work here, because the binary output variables are not independent?


What is the difference between "merged" questions and "closed (exact duplicate)" questions?

While looking at  I noticed that the question has been merged:    What is the difference between a merged question, and one that has been closed as a duplicate?


How a battery maintains the current in the circuit?

How a battery maintains the current in the citcuit? Iwant to know each and every step of this process mathematically and theoretically also.


Should I warn my professor about some errors that I've found in his paper?

A professor of mine gave me a paper, because he wanted to show me the kind of work that we might do together in future. It is the advance access version of the paper, but I've found some errors, like typos, and wrong references of some figures in the text. Should I warn him about those things? If so, what would be the best way to do that?   Update   I'm from Italy, but I would love to know about other different cultures as well, especially USA; My professor is very open minded, nice and easy-going; Let's put it this way: if I was a computer I wouldn't understood the meaning of the figures because the references in the text don't match with the right plot, but since I'm human being I've understood that he meant the other figures.   I believe that pride is less important than the truth, especially when it comes to scientific publications. I mean, everyone can be wrong, there is nothing bad about it in my opinion. But I know that not anyone think the same, so I've asked this question because I wanted to know if it's worth to risk what @littleScala pointed out, to spread higher quality articles around the world and to show meticulousness in reading the paper.  Basically I thought:    Maybe a professor could be nicely impressed by such a level of attention; What if he find its own errors? He might think that I didn't read the paper with caution.


Blender 2.72  Boolean operations with the primitive forms give expected results.  Trying to use a e.g. cube to remove the tabs from a hand by difference to leave the hand doesn't give the expected result.   Trying to use the cube in the same position with an intersection does not result in the removed tab. One of the operations looks like a union. Any suggestions? If you want more info, please tell me how to obtain it.  I'm not having a good day with Blender.


Using matrix algebra prove that $ \left = \left$

If A is an $m \times n$ matrix using matrix algebra prove that $\langle A\textbf{x}, \textbf{y} \rangle$ = $\langle \textbf{x}, A^T \textbf{y} \rangle$ for $x \in \mathbb{R}^n$ and $y \in \mathbb{R}^m$.  My approach: let $m = 2, n = 1$   $A = \begin{pmatrix}    1\\    2 \end{pmatrix} $, $ A^T = \begin{pmatrix} 1 & 2 \end{pmatrix} $, $ \textbf{x} = (1)$, $\textbf{y} = \begin{pmatrix} 2 \\ 3 \end{pmatrix}$   Then   $A\textbf{x} = \begin{pmatrix} 1 \\2 \end{pmatrix}$  $\langle A\textbf{x}, y \rangle = 1*2 + 2*3 = 8$  $A^T\textbf{y} = 8 $  $\langle \textbf{x}, A^T \textbf{y} \rangle = 8 $   $\langle A\textbf{x}, \textbf{y} \rangle$ = $\langle \textbf{x}, A^T \textbf{y} \rangle$  However I'm pretty sure this answer isn't satisfactory. What can I do to improve it?


Why on the first page Google says there are thousands of results but on the last page there are less than a hundred?

That's kind of a recursive Google Search that should be self-explanatory. It did take me some time to tweak the sentence and trying to find a number which would correspond precisely, the reason why I changed it to "hundreds" instead! :P  If you have used Google long enough you certainly have stumbled on situations similar to this, many times. Whenever it shows less than 10 pages it's quite easy to see it. The point is: the number of results on any page except the last one seems like a terrible estimate.  What's even weirder,  the estimate suddenly becomes much better and almost exactly the same on all pages than it is on the last page - the only page that's always correct.  So, anyone knows why?


Are there any roleplaying guidelines for Science Talk

I'm going to try my best with roleplaying a crazy Scientist. However I have got a problem with 'Science talk'. I was wondering, are there any techniques or guidelines for nerd/technical talk, which does not irritate other players, or sound just too cheesy (when used by someone who does not have so much technical knowledge)?  We are a small group which will create a rebel cell.  My character is a  scientist (chemist and physicist) previously working for the Empire.  Unappreciated by the Empire because of his race he joined the Rebels.  He thinks that the Empire should regret ever doubting his genius.


LM741CN Wired as Voltage Follower Will not Output less than 2V

I have designed a circuit to measure 0-12.2V and Scale it to 0-10V from a PLC input to read. I have put an LM741CN in the circuit as a voltage follow to isolate the test circuit from the measurement circuit.  All is well except that when I input less than 2V into the op amp it stops following the voltage and continues to output about 2V I have input 0V into it and I still get about 2 volts out.  I can't find anything on the spec sheet about there being a minimum voltage output. What am I doing wrong?         – Schematic created using


Lilly loved James whose Patronus was a stag, therefore hers became a doe. Snape hid that he loved Lilly for so long, what if Snape's Patronus was a doe because he loved Harry, whose Patronus was a stag?


Every time I run sudo apt-get update, I get this error:  W: GPG error: https://download.01.org Ubuntu Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A902DDA375E52366   What should I do? I'm using Ubuntu 12.04 LTS.


I've been typesetting some equations, and I've found that the default behavior accents like \hat, \bar, \tilde, etc. makes a rather small and easily-missed mark. Is there some way to make the accents stand out more? In particular, is there any way to make them appear in bold (without affecting the letter they are over)?


Proof by induction: $\sum\limits_{i=1}^{n} \frac{1}{n+i} = \sum\limits_{i=1}^{n} \left(\frac{1}{2i-1} - \frac{1}{2i}\right)$

How can the following be proved by induction?  $$\sum\limits_{i=1}^{n} \frac{1}{n+i} = \sum\limits_{i=1}^{n} \left(\frac{1}{2i-1} - \frac{1}{2i}\right)$$ I am out of ideas after practicing for a while:  $$\frac{1}{n+1}+\frac{1}{n+2}+\dots+\frac{1}{2n}=\left(1-\frac{1}{2}\right)+\left(\frac{1}{3}-\frac{1}{4}\right)+\dots+\left(\frac{1}{2n-1}-\frac{1}{2n}\right) $$  Does this involve telescoping series?


Each of 15 red balls and 15 green balls is marked with an integer between 1 and 100 inclusive; no integer appears on more than one ball. The value of a pair of balls is the sum of the numbers on the balls. Show that there are at least two pairs consisting on one red ball and one green ball, with the same value. Show that this is not true if there are 13 balls of each colour.  since each ball has a different number and if no two pairs have the same value there is going to be $15*15$ different sums. Looking at the numbers 1 through 100 the highest sum is 199 and lowest is 3, giving 197 possible sums. Since $15*15 = 225 > 197$ there must be two pairs with the same colour.   Looking at the 13 case, $13*13 = 169 < 197$ and so there is not necessarily two pairs with the same sum.  My question is; is my reasoning correct, is there a more elegant proof and what category does 14 fall under?  This question is from 'An Introduction to Combinatorics and Graph Theory' and falls under the Pigeon-Hole principle and Ramsey numbers.  For the case of 14, $14*14 = 196 < 197$ but which would indicate that there are not two pairs with the same sum, yet the question defaulted to 13 rather than 14 suggesting otherwise.


bash: cannot create temp file for here-document: No space left on device

My server is currently down. Apparently he has no room. How do I solve this?       danilodorgam@ny3-vps:/etc$ df     Filesystem                1K-blocks     Used Available Use% Mounted on     udev                         504600        4    504596   1% /dev     tmpfs                        101788      336    101452   1% /run     /dev/disk/by-label/DOROOT  30830588 12305880  16935572  43% /     none                              4        0         4   0% /sys/fs/cgroup     none                           5120        0      5120   0% /run/lock     none                         508924        0    508924   0% /run/shm   ...   df -ih Filesystem                Inodes IUsed IFree IUse% Mounted on udev                        124K   402  123K    1% /dev tmpfs                       125K   312  124K    1% /run /dev/disk/by-label/DOROOT   1.9M  1.9M     0  100% / none                        125K     2  125K    1% /sys/fs/cgroup none                        125K     1  125K    1% /run/lock none                        125K     1  125K    1% /run/shm none                        125K     2  125K    1% /run/user


I have 50 PDFs files and I want to extract first page of each file i do not know how it is to be done? kindly help me for this problem.


I am wondering how I can read CSS comments out of a linked stylesheet.  I have this sample CSS loaded via:  <link rel="stylesheet" type="text/css" media="all" href="test.css" />      #test1{ border:1px solid #000; } #test2{ border:1px solid #000; } #test3{/* sample comment text I'm trying to read */}   I'm testing this in FF3. The following javascript reads the rules but doesn't read the comments in#test3.  window.onload = function(){     s=document.styleSheets;     for(i=0;i < s[0].cssRules.length;i++){         alert(s[0].cssRules[i].cssText);     } }


Where can I find documentation for the \nolinebreak command?

Where can I find documentation on how to use the \nolinebreak command?  The  at  never makes mention of \nolinebreak  The  states that \nolinebreak is implemented by multiplying its input parameter penalty by (-1) and passing the result into \nopagebreak.       I haven't found documentation on how to use the command.


Transistors: Quiescent voltage and Active mode

I am struggling to understand two things about this circuit.  1) when input and output terminals are open circuit, why is this assumed to be in active mode?  2)What range can the quiescent output voltage of the amplifier be in?  Now I know that active mode you need EBJ to be forward bias and CBJ to be reverse bias but how would this apply in this scenario?  I understand what quiescent voltage is but I am struggling to apply his here with the input and output terminals. I would appreciate any help.  Many thanks.


how prove $\phi(n)\ge \frac{n}{6\log \log (n)} $ $\forall n\ge5 $

How to prove$\forall n\ge5 $      $$\phi(n)\ge \frac{n}{6\log \log (n)} $$    $\phi$ is Euler function  Thanks in advance


Is there a symmetry associated to the conservation of information?

Conservation of information seems to be a deep physical principle. For instance, Unitarity is a key concept in Quantum Mechanics and Quantum Field Theory.  We may wonder if there is an underlying symmetry, in some space, which may explain this conservation of information.


How to start a terminator instance always with a set of terminals (each one in a different directory) in one window

I want to open the same set of directory locations in one terminator window as multiple terminals every time by default (or when I run a script). I think it could be done via profiles or layouts.  was not very helpful.


If $\gcd(b,c) = 1$, $b$ and $c$ divides $a$, then $bc$ divides $a$

this lemma is a corollary of the following lemma: if $\gcd(b,c)=1$ $gcd(a,bc)=gcd(a,c)gcd(a,b)$


Why was this character in Avengers: Infinity War in Vormir?

We know Red Skull is in Captain America: The First Avenger, but why is he in Vormir in the first place? How did he get there?  Apart from Marvel trying to close Phase: One, what was the point of portraying this character in this movie?


Any way to fix out of sync embedded mkv subtitles?

The subtitles built into the video are off I think because a different framerate than the video.  They start out synced but within a minute or so they start getting behind and by the 7:30 mark the subtitles are about 15+ seconds behind.  Do I need to extract the subs, change their framerate, and then re-embed them?  That sounds really complicated.  I read about something called "advance synchronization functionality" but I can't seem to find that anywhere.  TIA


I am confused by the floating-point precision problem in python. for example: 48.91 multiplies 10000: > 48.91 * 10000 489099.9999999999994  I lose the precision, but if I directly type in 48.91 as float, it can perfectly represent it. > 48.91 48.91  > float(48.91) 48.91  So how come sometimes It can keep the precision while sometimes It can't?? How to deal with this situation??


Show that both sequences converge to a common limit

Show that if $a_1>b_1>0,a_{n+1}=\sqrt{a_nb_n}$ and $b_{n+1}=\frac{a_n+b_n}{2}$, then $a_n$ and $b_n$ both converge to a common limit.  It seems a bit intuitive but I am not able to get it in writing. I tried using Cauchy's test but it isn't helping(introducing more variables). Some help please. Thanks.


How to reference an Annex (A)?  I've tried \ref{Annex A}, but this wouldn't work.


Will stay less than 90 days in Germany, but will work there, what kind of visa do I need?

I'm a Chinese citizen living in US and I will work in Germany for less than 90 days, what kind of visa do I need? Business visa (Schengen visa) or employment visa (residence visa)?


This is a PC with no prior OS, I slapped Ubuntu on temporarily. I do prefer Ubuntu but it's (unfortunately) just not well optimised for games ;_; Anyway I'm pretty computer illiterate when it comes to partitioning, OSes and BIOSes so if anyone can tell me how to remove Ubuntu easily and leave my PC like it was when it was put together with no OS. Thanks!


Windows 7 x64 Out of Memory Error - With over 1GB still available

I've been getting sporadic "Out of Memory" popups while playing games in fullscreen windowed mode lately (namely Arma 3 and BF4). I didn't get these before switching from fullscreen to fullscreen windowed, but it may be unrelated. However, when these warnings pop up, I usually jump into Resource Monitor to have a look at the current state of my system memory, and there's always less than 2GB being used by the game in question, and still 1-3GB still in standby.  Is this normal to have it pop up this early, or is Resource Monitor displaying my available memory wrong (or, do I not understand what the "Standby" portion is)? It appears to be a legitimate issue, because I tend to get notifications of failed memory allocation by other programs at the same time.  I'm running 64-bit Windows 7, and have 8GB of RAM installed.


Why do we care if an MA process is invertible?

I am having trouble understanding why we care if an MA process is invertible or not.  Please correct me if I'm wrong, but I can understand why we care whether or not an AR process is causal, ie if we can "re-write it," so to speak, as the sum of some parameter and white noise - ie a moving average process. If so, we can easily see that the AR process is causal.  However, I'm having trouble understanding why we care whether or not we can represent an MA process as an AR process by showing that it is invertible. I don't really understand why we care.  Any insight would be great.


Given two groups $G$ and $H$ and a homomorphism $i:G\rightarrow H$. It is clear that the image $i(G)$ is again a sub-group of $H$, if the mapping $i$ is injective.   Question: What if $i$ is not injective? Does the image still forms a subgroup? If not, why?


I need to get the row with latest date in my table. I have tried using where rownum = 1 as well as using max function but I dont seem to get the correct result.   This is what I have tried, this gives me more than one rows, I want the row with the max date:  SELECT * FROM (SELECT col1,col2,coldate3,max(colDate3)  over (partition by coldate3) max_date FROM MY_TABLE  WHERE  TRIM(col1) = TRIM('abc')  AND TRIM(col2) = TRIM('efg') ) where coldate3= max_date;   I have also tried this, this gives me the max date but value of col1 is of some other row:   SELECT MY_TABLE.TARIFF  FROM MY_TABLE  WHERE ROWNUM = 1  AND TRIM(MY_TABLE.col1) = TRIM(:ls_col1)  AND TRIM(MY_TABLE.col2) = TRIM(:ls_col2)  ORDER BY coldate3 desc   What am I doing wrong.


which of the following is/are true for $f$?

Let $f$ be a meromorphic function on $\mathbb C$ such that $|f(z)|\ge|z|$ at each $z$ where $f$ is holomorphic. Then which of the following is/are true?   The hypothesis are contradictory. Such an $f$ is entire. There is a unique $f$ satisfying the given conditions. There is an $A\in\mathbb C$ with $|A|\ge1$ such that $f(z)=Az$ for each $z\in\mathbb C.$   I think 2 and 4 are correct. But I can't proceed rigorously. Neither do the discussion  is complete.


Emission of particles parented to a high velocity object

As shown in the video, I have an object that move at high speed in 3d space. But the emitter does not have time to emit particles all the way. It creates particles for each frame. But to emit particles constantly with a moving object? Thank you for your time.


Setting the file modified time to show seconds in Explorer

Does anyone know how to set Windows Explorer Details View to allow the file modified time to show the number of seconds? This used to work in old Win XP. Since the wizards at MS seemed to have removed that capability is there a GPO or a registry setting that might still allow for this setting?...such that Explorer Details View would show HH:MM:SS in the Modified time column. Thank you for any guidance, history, reason, etc...


Primitive element of the finite field $\mathbb{F}_8$ over $\mathbb{F}_2$

I am having lots of problems finding a primitive element. First we have that $|\mathbb{F}_8| = 8 = 2^3$, therefore its prime subfield is $\mathbb{F}_2$ and $[\mathbb{F}_8 : \mathbb{F}_2] = 3$. Hence, $\mathbb{F}_8 \cong \mathbb{F}_2[X]/($irreducible polynomial of degree 3$)$ In $\mathbb{F}_2$ the only irreducible polynomials of degree 3 are: $p(x) = x^3+x^2+1 $ $p(x) = x^3+x+1$ Then, we have   $\mathbb{F}_8 \cong \mathbb{F}_2[X]/(x^3+x^2+1) \cong \mathbb{F}_2[X]/(x^3+x+1)$ So here is my first question: can I say that the elements of $\mathbb{F}_8$ are the 6 roots of said polynomials and the 0 and 1 (the elements of $\mathbb{F}_2$)? I know that at least, it would be correct to state that $\mathbb{F}_8 = \{0, 1, x, x+1, x^2, x^2 + 1, x^2 + x, x^2 + x + 1\} $, but for this it would not have been necessary to find the previous isomorphism. Now, I need to find a primitive element $\alpha$ such that $\mathbb{F}_8 \cong \mathbb{F}_2(\alpha)$. Knowing that the extension is of degree 3, ($\mathbb{F}_8 = \mathbb{F}_2 \langle 1, \alpha, \alpha^2 \rangle$), I guess that one way would be to square the elements of $\mathbb{F}_8$ and find two that are linearly dependent, but if I say that the elements are the roots of the polynomials then I do not know how to proceed. Thanks in advance! Any help would be appreciated! :)


I am reading the book Elements of Statistical Learning and trying to understand singular value decomposition (SVD). In particular, what is an orthogonal matrix as it relates to SVD?  According to Wikipedia, an orthogonal matrix is a square matrix, the transpose of an which is equal to its inverse.   As this CrossValidated question points out however, in the SVD example discussed in Elements of Statistical Learning, this does not hold.   What am I missing?


Is the Windows8/10 start screen capable of spanning 2 monitors?

Is the Windows8 start screen capable of spanning 2 monitors?  This is not a question of multiple monitor support; this is a question of whether the Windows-8 start screen is able to display across 2 monitors, not as a mirrored display but as a additive display to the width of the single screen start screen.   Or, does a app exist that I can purchase for it to do this?


Install pdflatex by installing texlive on Ubuntu from texlive site?

I want to install pdflatex. It is in texlive-latex-base in my Ubuntu 14.04 repository. But I don't want to install texlive-latex-base, because Ubuntu repository usually has outdated software.  So I download install-tl-unx.tar.gz  from , and run sudo ./install-tl. After an hour and half, it finishes running.   But I still don't have pdflatex when I run pdflatex in terminal.  Added: I found it is installed at /usr/local/texlive/2014/bin/x86_64-linux/pdflatex. Is it supposed to be there and not found when I run pdflatex? Does  install-tl install the same as texlive-latex-base?  In order to install pdflatex, do I need to install install-tl-unx.tar.gz from Ubuntu repository? Can I keep the installed texlive by install-tl, and avoid installing the outdated texlive in texlive-latex-base?   Thanks.


In Bong Joon-ho's Parasite (2019), lead character Kim Ki-taek (driver of Mr. Park) suddenly      kills Mr. Park at the end when he says something about "smell of rotten stink".    But in the entire movie, they have shown the Park family to have a good heart (though they are rich and dumb). Even in the scene where Mr. Park tells his wife about his driver's bad smell, he in fact heaps praise of his driver for not “crossing the line".  So why did Kim       kill Mr Park?


How do you cross-validate moving time predictions?

I have a model that trains itself by looking at the last 12 months of data, and then predicts the next month (out of sample).  Say I have 24 months worth of data, thus allowing me 12 opportunities to train and test my model (train: months 1-12; test: month 13; train: months 2-13; test: month 14, etc.)  How would I cross-validate this?


Arithmetic precision problems with large numbers

I am writing a program that handles numbers as large as 10 ** 100, everything looks good when dealing with smaller numbers but when values get big I get these kind of problems:  >>> N = 615839386751705599129552248800733595745824820450766179696019084949158872160074326065170966642688 >>> ((N + 63453534345) / sqrt(2)) == (N / sqrt(2)) >>> True   Clearly the above comparision is false, why is this happening?  Program code:  from math import *  def rec (n):     r = sqrt (2)     s = r + 2     m = int (floor (n * r))     j = int (floor (m / s))     if j <= 1:         return sum ([floor (r * i) for i in range (1, n + 1)])     assert m >= s * j and j > 1, "Error: something went wrong"     return m * (m + 1) / 2 - j * (j + 1) - rec (j)  print rec (1e100)   Edit:  I don't think my question is a duplicate of the linked question above because the decimal points in n, m and j are not important to me and I am looking for a solution to avoid this precision issue.


Publishing results posted Stack Exchange

Recently, I asked a question on stack exchange, to check if something I am working on was already done. I myself could not find this specific thing, so I asked the community.   Then, a discussion about my problem followed, and some people provided (possibly inaccurate) proofs. Independently, I figured out a proof by myself.  Now, I want to publish the proof of my result. Is this ok? Can I post this on Stack Exchange and then still publish it?


How to create stack overflow comment with external website link

I have come across comments such as below.   Which contains link to external website but http url does not show up in the comment instead user provided word come up, upon clicking that word will lead to external website(example "help center", "Minimum, Complete and Verifiable example").


Suppose $n$ is a positive integer. Decide the remainder of $x^{2n}-x^{n}$ when divided by $2$

So, I tried solving this problem in the following way (though I think I'm begging the question...)  The possible remainders of $x^{2n}-x^{n}$ when divided by $2$ is $0$ and $1$. We wish to solve the following congruence $x^{2n}-x^{n}\equiv b\pmod 2$, where $b=0$ or $b=1$.  Now, Suppose $b=0$ (this is where I think I'm begging the question!). Then $x^{2n}-x^{n}\equiv 0\pmod 2 \Leftrightarrow 2\vert (x^{2n}-x^{n}-0) \Leftrightarrow x^{2n}\equiv (x^{n})^{2}\equiv x^{n}\pmod 2$. If we let $a=x^{n}$. Then it is clear that $(x^{n})^{2}\equiv x^{n}\pmod 2 \Leftrightarrow a^{2}\equiv a\pmod 2$ and by Fermat's little theorem we know that $a^{2}\equiv a\pmod 2$ is true. Thus $x^{2n}-x^{n}$ has a remainder of $0$ when divided by $2$.  Is this correct? Or am I just begging the question?


What is the proof that the total number of subsets of a set is $2^n$?

What is the proof that given a set of $n$ elements there are $2^n$ possible subsets (including the empty-set and the original set).


How can I find all files I do not have write access to in specific folder?

How can I find all files I can not write to?  Would be good if it takes standard permissions and acls into account.  Is there an "easy" way or do I have to parse the permissions myself?


Subtracting two numbers of the same value is not 0

Why would the following code not result in 0? $payments = [439.53, 36.69]; $total = 0;  foreach ($payments as $p) {     $total += $p; }  // float 476.22 var_dump($total);   $invoice = 476.22; // float 476.22 var_dump($invoice);  $balance = $invoice - $total; // float 5.6843418860808E-14 var_dump($balance);  If I round the result it returns 0: // float 0 var_dump(round($balance, 2));


I want to know why the first result is different from the second one?  full code:  public static void main throws Exception {         KeyGenerator kg = KeyGenerator.getInstance("RC2");         SecretKey sk = kg.generateKey();         byte[] key = sk.getEncoded();          System.out.println(Arrays.toString(key));         System.out.println("****");         SecretKey sk1 = new SecretKeySpec(key, kg.getAlgorithm());          boolean status = sk1.equals(sk);           System.out.println(status); //the result is true         System.out.println(sk1==sk); //the result is false }


Can I add a "new -> blank document" option to the context menu?

I was wondering if it was possible to add the option to create new documents without extension from the context menu.      This would enable me to create and structure my applications faster and more directly than every other alternative, such as:       Have "hide knows file extensions..." permanently disabled; create new .txt file; change extension; accept Windows "changing an extension..." warning. Open text editor; write specific file; save as; navigate to directory, change extension, save.  for every type of file.   Instead, I could just do:       New blank file, add extension, repeat.       If it's of any importance, I'm coming from working mostly through Filezilla and its context menu works like that.


How to select a subset of variables from my original long list in order to perform logistic regression analysis?

My situation:   small sample size: 116 binary outcome variable long list of explanatory variables: 44 explanatory variables did not come from the top of my head; their choice was based on the literature.   Statistical test chosen: logistic regression  I need to find the variables that best explain variations in the outcome variable (I am not interested in making predictions).  The problem: This question is a follow-up on the 2 questions listed below. From them, I got that performing automated stepwise regression has its downsides. Anyway, it seems that my sample size would be too small for that. It seems that my sample is also too small to enter all variables at once (using the SPSS 'Enter' method). This leaves me with my issue unresolved: how can I select a subset of variables from my original long list in order to perform multivariate logistic regression analysis?  UPDATE1: I am not an statistician, so I would appreciate if jargons can be reduced to the minimum. I am working with SPSS and am not familiar with other packages, so options that could be run with that software would be highly preferable.  UPDATE2: It seems that SPSS does not support LASSO for logistic regression. So following one of your suggestions, I am now struggling with R. I have passed through the basics, and managed to run a univariate logistic regression routine successfully using the glm code. But as I tried glmnet with the same dataset, I am receiving an error message. How could I fix it? Below is the code I used, followed by the error message:  data1 <- read.table("C:\\\data1.csv",header=TRUE,sep=";",na.string=99:9999)  y <- data1[,1]  x <- data1[,2:45]  glmnet(x,y,family="binomial",alpha=1)    **in lognet(x, is.sparse, ix, jx, y, weights, offset, alpha, nobs,  :  (list) object cannot be coerced to type 'double'**   UPDATE3: I got another error message, now related to missing values. My question concerning that matter is .


What does a round icon with a horizontal line in its middle show?

I'm using a nightly build of CM13. I recently noticed this round icon with a horizontal line in its middle. The icon is located in the right side of the notification bar.     What does that icon depict?


Bessel function equation with derivation: $\frac{d}{dx} (xJ_{\alpha}(x)J_{\alpha+1}(x)) = x(J_{\alpha}^2(x)-J_{\alpha +1}^2(x))$

Let $J_{\alpha}(x)$be the Bessel function. Show the equality:  $$\frac{d}{dx} \left( xJ_{\alpha}(x)J_{\alpha +1}(x)\right) = x \left( J_{\alpha}^2(x) -J_{\alpha +1}^2(x)\right)$$  How to start with it?


How to remove shortcut key for Unity , which is "Meta" key on keyboard

I'm a big fan of Meta key , but in Unity interface , by pressing that key , unity's interface will show up , hindered further action with that key , e.g Meta + Tab.  Without hacking its source code , anyway to remove that shortcut key ?


How to remove a header and footer from a Google Drive document?

Is there a way to remove a header and footer from a Google Drive document?


on the factorization of maps between connected CW complexes

I'm working on problem 16 in section 4.1 of Hatcher's Algebraic Topology book. I really have no ideas so far:  Show that a map $f: X \to Y$ between connected CW complexes factors as a composition $X \to Z_n \to Y$ where the first map induces isomorphisms on $\pi_n$ for $i\le n$ and the second map induces isomorphisms on $\pi_n$ for $i\ge n+1$.  Any help is appreciated.


This problem is in Stein.  In $L^p$, $1\leq p<\infty$ on $\mathbb{R}^d$ with measure lebesgue.  (a) Continuous function with comppact support are dense in $L^p$. I have already proves this :) (b) Infinitely differentiable functions with compact support are dense in $L^p$.  How proves (b)? I read that this hard...


cannot add sudo add-apt-repository ppa:kubuntu-ppa/backports in ubuntu 16.04

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Check whether the series is conditional converges or absolutely converges $\sum_{n=1}^{\infty}\left(\frac{-n}{n+1}\right)^n$

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