Does String theory say that spacetime is not fundamental but should be considered an emergent phenomenon?  If so, can quantum mechanics describe the universe at high energies where there is no spacetime?  Schrodinger equation assumes the presence of time dimension. So how can such equations be valid at extremely high energy?  And is it meaningful to do physics if there is no time dimension?  Would the concepts of Hilbert space, wavefunction collapse etc be useful in that case?


Is the Panasonic GH5's sensor likely to get damaged while in my bag?

The Panasonic GH5's sensor is suspended in a magnetic field when in use, allowing it to move on 5-axis to stabilise the image.   However when not in use it is completely loose and flops around in its space (it can move around by a good 3-4mm in all directions) and it can clearly be heard and felt knocking around, presumably it has some sort of rubber buffers around it.   However in the long term, being carried in a camera bag, rucksack, handbag, neck-strap etc etc... Is it likely to suffer any actual physical damage? Is the flexible cable to it likely to degrade in time?   I am fully aware that they are built like this, and have of course been thoroughly tested, but sometimes there are unforeseen issues later in the life of products.


Solve system of simultaneous equations in $3$ variables: $x+y+xy=19$, $y+z+yz=11$, $z+x+zx=14$

Solve the following equation system:  $$x+y+xy=19$$ $$y+z+yz=11$$ $$z+x+zx=14$$  I've tried substituting, adding, subtracting, multiplying... Nothing works. Could anyone drop me a few hints without actually solving it? Thanks!


I am traveling from the UK to Mexico via USA, do I need to apply for a visa waiver program (ESTA)


There are plenty of examples of differentiable functions $\Bbb R\to\Bbb R$ with derivatives that are not everywhere continuous. However, as stated , it is impossible for the derivative to be nowhere continuous. In general, can anything be said about exactly how "ugly" a derivative can get?


I have to remove a specific set of words from a string. E.g. following words needs to removed (ooh,aah and etc) from an employee_description. Below query I have tried:  SELECT REPLACE(REPLACE(emp_desc, 'aah', ''), 'ooh', '') from TEST_Table;   It's working fine.  But is there any other Best Way to do this.


Should I prevent search engines indexing tag/category pages?

On my site, I currently have no special rules for search engines. It is a blog, statically generated using a Python program. When I search for some of my articles on Google, there is usually a tag or category page included in the results. Sometimes it even ranks ahead of the article itself. Obviously, as these links aren't always going to have the article on them, this aren't the results I want people to click on.  So, I'm thinking of setting noindex on these pages. Is there any possible downside to doing so? Is this possible to do via robots.txt, or do I have to add it to all the relevant templates? All I can find for robots.txt are ways to stop the search engine crawling those pages, which isn't what I want - while I don't want them indexed, it's still the only surefire way to find all my blog posts.


How to upgrade shared library without crash?

it says that you can rewrite an executable file and the process will run just fine - it will be re-read when a process restarts.  However, when I try to replace a binary file while the process is running (with scp, from dev to test server) it says 'file busy'. And if I replace a shared library file (*.so), all the processes that link it crash.  Why so? Am I missing something? How can I replace the binary files without stopping/crashing a process?


Physics behind a match performing a trick on center of mass

I've seen another variation where the whole match stick turned to ash.  What's going on in this trick?


I created a test room on chat, but I can't see how to delete it.


Array defined as "_end[LEN]" causes segmentation fault in C/C++

I tried to define a global array, named _end, of size ~1000 in C/C++, but I got a segmentation fault even when I simply iterated it. Is the name "_end" very special in C/C++ that causes such problem? Or this can be a very serious bug... (The code is attached below, and it breaks in g++ 4.3.2, 4.5.2, 4.9.2, etc.)  #include <iostream> using namespace std;  int _end[1111];  int main() {     for (int i=0; i<1111; i++) {         cout << i << endl;         _end[i]++;     }     return 0; }   You can see the result at . See  also for the C compiler.


Why can't python find a child package when importing a package?

I have a project organized as such: proj ├── main.py ├── netbatch │   ├── __pycache__ │   ├── monster.py │   └── test_monster.py └── workers     ├── __pycache__     ├── ldb     │   ├── __pycache__     │   └── handle.py     └── strawberry.py  strawberry.py contains import ldb.handle ... if __name__ == '__main__':  and main.py contains import workers.strawberry import workers.ldb.handle  When I run strawberry.py the import works as expected, but when I run main.py, I see the error:   File "/tmp/proj/workers/strawberry.py", line 3, in <module>     import ldb.handle ModuleNotFoundError: No module named 'ldb'  I'm using version 3.6.3


How do character stats affect the personality of the character?

When creating a character we obviously place our stats where they are needed. What I am wondering is how do those stats effect the character itself from a role playing perspective.  I went back and read through the PHB pages 173-178. There was a bit about how the stats effect some parts of the character, but not what I was looking for. What I was thinking of was something along the lines of a range of a stat determines a bit of how the character is role played.  For instance does low intelligence (e.g. < 6) always mean that the character cannot read?  Or a low charisma mean the character is a jerk?  Are there rules governing this? Or would this be purely governed by the DM and rules agreed on by the group?


Why is the complex plane shaped like it is?

It's always taken for granted that the real number line is perpendicular to multiples of $i$, but why is that? Why isn't $i$ just at some non-90 degree angle to the real number line? Could someone please explain the logic or rationale behind this? It seems self-apparent to me, but I cannot actually see why it is.  Furthermore, why is the real number line even straight? Why does it not bend or curve? I suppose arbitrarily it might be strange to bend it, but why couldn't it bend at 0? Is there a proof showing why?  Of course, these things seem natural to me and make sense, but why does the complex plane have its shape? Is there a detailed proof showing precisely why, or is it just an arbitrary choice some person made many years ago that we choose to accept because it makes sense to us?


What kinds of quotes to use with mysqli_real_escape_string?

I created the following script in procedural mysqli because I am just starting from the old mysql. I am not sure about the kinds of quotes around the query to prevent injections. Some users post examples with ' others with ", so now I'm confused. Can I get injected or attacked with the following code and what are the correct kinds of quotes?  $username = mysqli_real_escape_string($database,$_POST['form_user']); $password = mysqli_real_escape_string($database,$_POST['form_password']);  $members = "SELECT * FROM `accounts` WHERE `member` = '$username'"; $result = mysqli_query($database,$members);   I am just a beginner so object oriented or PDO or prepared statements are difficult for me at this moment so I just need to improve this script and make it safer but with so many examples and symbols around query vars I am confused about what is and is not safe.


Binomial coefficient identity $\sum_{k=1}^n k {n \choose k } = n\cdot 2^{n-1}$

I'm having a bit of problems proving the following: $$\sum_{k=1}^n k {n \choose k }  = n\cdot  2^{n-1}$$  I always seem to get to the line: $2^{n-1} + 1 = 2^n$ which I know is untrue.  Could anyone help me prove this?


Is there a way of taking a snapchat filter off a saved image? Its a leopard nose and ears and would like to know if i can get them off or if any one else could?


Show that there exist $[a,b]\subset [0,1]$, such that $\int_{a}^{b}f(x)dx$ = $\int_{a}^{b}g(x)dx$ = $\frac{1}{2}$

Let $f(x)$ and $g(x)$ be two continuous functions on $[0,1]$ and  $$\int_{0}^{1}f(x) dx= \int_{0}^{1}g(x)dx = 1$$   Show that there exist  $[a,b]\subset [0,1]$, such that  $$\int_{a}^{b}f(x) dx= \int_{a}^{b}g(x)dx = \frac{1}{2} $$  The question can be solved by considering the fundamental group of $S^1$, now I am wondering if we can solve it by real-analysis.  Here is the topological solution:  Assume that for any $[a,b]\subset[0,1]$, we always have  $$(\int_{a}^{b}f(x) dx\neq \frac{1}{2}) \quad \vee \quad(\int_{a}^{b}g(x)dx \neq \frac{1}{2}) $$ Consider mapping $$\phi:D\rightarrow\mathbb{E}^2\backslash\{(\frac{1}{2},\frac{1}{2})\},\,\,(x,y)\mapsto(\int_{y}^{x}f(t) dt,\int_{y}^{x}g(t) dt)$$ where $D=\{(x,y)|0\leq x\leq y\leq 1\}$.  Let $a$ be path from $(0,0)$ to $(0,1) $in $D$ and $b$ be path from $(0,1)$ to $(1,1) $in $D$, then $ab$ is a path from $(0,0)$ to $(1,1) $in $D$ and $$\phi\circ (ab):[0,1]\rightarrow\mathbb{E}^2\backslash\{(\frac{1}{2},\frac{1}{2})\} $$ Notice that $$(\phi\circ (ab))(0)=(\phi\circ (ab))(1)=(0,0)$$  so $\phi\circ (ab)$ is a loop based on $(0,0)$ in $\mathbb{E}^2\backslash\{(\frac{1}{2},\frac{1}{2})\}$.  For any $t\in [0,\frac{1}{2}]$, it's not hard to get that $$(\phi\circ (ab))(t+\frac{1}{2})=(1,1)-(\phi\circ (ab))(t)$$ is equivalent to $$(\phi\circ (ab))(t+\frac{1}{2})-(\frac{1}{2},\frac{1}{2})=-((\phi\circ (ab))(t)-(\frac{1}{2},\frac{1}{2}))$$  Define retraction  $$r:\mathbb{E}^2\backslash\{(\frac{1}{2},\frac{1}{2})\}\rightarrow S^1,\quad (x,y)\rightarrow\ \frac{(x,y)-(\frac{1}{2},\frac{1}{2})}{||(x,y)-(\frac{1}{2},\frac{1}{2})||}$$  Then $r\circ \phi\circ (ab)$ is a loop on $S^1$, such that $$(r\circ \phi\circ (ab))(t+\frac{1}{2})=-(r\circ \phi\circ (ab))(t),\quad\forall t\in [0,\frac{1}{2}]$$  So $<r\circ \phi\circ (ab)>$ is not trivial in $\pi_1(S^1)$.   However, $ab$ is path homotopic to $c$ in $D$, where $c$ is the path between $(0,0)$ and $(1,1)$ in $D$. In this case, $r\circ \phi\circ (ab)$ is a point-path in $S^1$ by $$(\phi\circ c)(t)=\phi(t,t)\equiv (0,0)$$  which leads to contradiction.


I started incubating a 10 km egg and I've collected 7 other eggs since then many that are 2 km and I am almost out of space. Is there a way I can switch incubation to one of the smaller eggs so I can clear my inventory faster?


When constructing tag wikis, it seems that the tag wiki of the same tag in different websites must be built every time.  It seems that there is something can be improved. It repeats much and is not .  For example:  The information of  in  softwareengineering.stackexchange.com could be the information of  on stackoverflow.com.  I guess most tag wikis of different websites of stackexchange.com could be the same.  Because the knowledge is there, and it reflects the truth.  On the other hand, different websites of stackexchange.com has their own feature. So the community wiki may be has a content offset accordingly.  The tag wiki is unified and has its own feature on different websites of stackexchange.com.  I don't know how to achieve it.    I don't think this question is a duplicate of .  The question is based on the fact. I found that many tags information on other websites programming-related is to copy small part of the tag info on Stack Overflow.  Another example:  on codereview.stackexchange.com is not much like the answer below at least now, compare to  on Stack Overflow.  The naming duplicate question seems that it looks good, and "I" think it is reasonable.  Talk is cheap; what I discussed exists on programming-related websites, not cooking.


I was wondering of what kind of subject are necessary to study the Yang - Mills theory from basic university level.   Can you suggest some good book for subject?


How do I get the difference between two timestamps?

I am creating a simple backup script. I would like to have a message saying "You last backed up x days ago" on login. I can create a file when I do the backup "backup/.last_backup_timestamp" but what format should I use and how would I find the difference in days between then and now in bash?  Thank-you


Unable to mount /dev/loop0 during install

I was installing 32-bit Ubuntu(ubuntu-10.10-desktop-i386.iso) on VMWare workstation 7.1. During installation an error came up with the following text.  (initramfs) mount: mounting dev/loop0 on //filesystem.squashfs failed: Input/Output error Can not mount /dev/loop0 (/cdrom/casper/filesystem.squashfs) on //filesystem.squashfs   I did a memory test which was successful, but when selecting "Try Ubuntu without installing", "Install Ubuntu" or "Check disk for defects" the same error is showing up.  I download the ISO image from Ubuntu website "http://www.ubuntu.com/desktop/get-ubuntu/download". As I couldn't find the checksum data, the ISO image was verified by mounting to a virtual drive and browsing the contents.  The ISO image is mounted to a virtual drive in VMWare and not burnt to a CD.


Interpeting residuals in a binary model (logistic regression, glm)

I know how to interpret residuals in a linear regression model. I am now working in a model that predicts a binary target combining numerical and categorical variables.  My residual plots is as follows:     If this were residual plots from a linear regression model I would be able to interpret them and notice that they are terrible. However I do not know if the same interpretation must be done when working with a logistic regression model.


You have exceeded the maximum number (100) of Apex scheduled jobs

Is there any workaround to overcome the above governor limit without aborting the job.  Thanks !


Proof - raising adjacency matrix to $n$-th power gives $n$-length walks between two vertices

I came across the formula to find the number of walks of length $n$ between two vertices by raising the adjacency matrix of their graph to the $n$-th power.   I took me quite some time to understand why it actually works. I thought it would be useful to write the proof by induction for this in my own words.    Theorem: Raising an adjacency matrix $A$ of simple graph $G$ to the $n$-th power gives the number of $n$-length walks between two vertices $v_i$, $v_j$ of $G$ in the resulting matrix.  Proof by induction: Let $P(n)$ be the predicate that the theorem is true for $n$. We let $F^{(n)}_{ij}$ be the number of $n$-length walks between vertex $v_i$ and $v_j$. $P(n)$ is then the predicate that $F^{(n)}_{ij} = A^n_{ij}$. We proceed by induction on $n$.  Base case: $P(1)$   Case 1: $F^{(1)}_{ij} = A^{(1)}_{ij} = 1$ if $\{v_i, v_j\} \in E$, so there is is a walk of length $1$ between $v_i$, $v_j$.  Case 2: $F^{(1)}_{ij} = A^{(1)}_{ij} = 0$ if $\{v_i, v_j\} \notin E$, so there can't be any walk of length $1$ between $v_i$ and $v_j$.   In both cases $F^{(1)}_{i j} = A^{(1)}_{ij}$ holds, hence $P(1)$ is true.  Inductive step: $P(n+1)$ For purpose of induction, we assume $P(n)$ is true, that is $F^{(n)}_{i j} = A^{(n)}_{ij}$ holds for $n$.  We can express a walk of length $n+1$ from $v_i$ to $v_j$ as a $n$-length walk from $v_i$ to $v_k$ and a walk of length 1 from $v_k$ to $v_j$.   That means, the number of $n+1$-length walks from $v_i$ to $v_j$ is the sum over all walks from $v_i$ to $v_k$ times the number of ways to walk in one step from $v_k$ to $v_j$. Thus:  $$F^{(n+1)}_{ij} = \sum_{k=1}^{|V|} A_{kj}F^{(n)}_{ik} = \sum_{k=1}^{|V|} A_{kj}A^{(n)}_{ik}$$  Which is the formula for the dot-product, used in matrix multplications.    Any feedback appreciated.


grep one line before the match plus the match

zzzzzzzzz aaaaaaaaa bbbbbbbbb & ccccccccc & ddddddddd hhhhhhhhh eeeeeeeee fffffffff & ggggggggg &   in the above line, what i want is to grep/sed/awk (any method is fine) line that have & sign plus one line on top of them. so for example the desired output will look like :  aaaaaaaaa bbbbbbbbb & ccccccccc & eeeeeeeee fffffffff & ggggggggg &   following is what i have tried with no luck.  egrep "&" | -b 1 file.txt


Not a duplicate - xampp not defaulting to index.php5, can I configure this?

xampp (on Windows) is working when I have an index.html or index.php file. I am using .php5 as an extension for new files in the project, and would like to use index.php5 for consistency. It is not a big deal, but my syntax highlighter is set up to color .php files differently, so I am reminded that they are older.  Can I configure xampp to use index.php5?  This is not a duplicate of the other question. The other question is about parsing and running .php5 files in general. This is not a problem on localhost and it is not a problem on any of servers I have running on goDaddy, rackspace and bluehost. The problem is specific to index.php5 - it parses and runs properly when the full name is typed in, but it is not recognized as the default when no file name is entered.  Can I configure xampp to DEFAULT to index.php5 given that php5 is working?


When i try to run these methods then i only get an error about nullpointexception while i've also have been checking my code and comparing it to similar applications but still i don't understand.  EDIT: I get an exception on the for loop line in the GUI code.  Ive built my application in MVC  GUI code:  public void actionPerformed(ActionEvent e) {              String pnr = textResPnr.getText();             String courseNr = textResCourseNr.getText();             ArrayList<Student> studentList = controller.results(pnr, courseNr);              String resultString = "";             for (Student student : studentList) {                 resultString = student.getPnr() + " " + student.getName() + " " + student.getGrade() + "\n";              }             textAreaResultat.setText(resultString);          }   My controller:  public ArrayList<Student> results(String pnr, String courseNr){     try {          student.setPnr(pnr);         course.setCourseNr(courseNr);         ArrayList<Student> studentList = null;         if(student.getPnr() != null){             dal.getResults(course, student);         }else{              studentList = dal.getAssignedStudents(course);             /*for (Student student : studentList) {              }*/         }          return studentList;     } catch (Exception e) {         return null;     } }   My Database Access Layer:  public ArrayList<Student> getAssignedStudents(Course course){     try {         Statement stmt = connection.createStatement();         ResultSet rset = stmt.executeQuery("SELECT Student.pnr, Student.namn, Registrering.betyg FROM Registrering INNER JOIN Student ON Registrering.pnr = Student.pnr WHERE betyg IS NOT NULL AND kursnr = '" + course.getCourseNr() + "';");          ArrayList<Student> studentList = new ArrayList<Student>();         while (rset.next()) {               String pnr = rset.getString("pnr");             String name = rset.getString("namn");             String grade = rset.getString("betyg");              Student student = new Student();              student.setName(name);             student.setPnr(pnr);             student.setGrade(grade);              studentList.add(student);          }         return studentList;     } catch (Exception e) {         System.err.println("Got an exception! ");         System.err.println(e.getMessage());         return null;     } }


Windows 10 TP: Menu Start doesn't appear anymore, and Cortana search is not working

The Start Menu in Windows 10 is not working anymore.  I click, and simply nothing happens.  I could use Cortana, build 9926, but when I click on the Cortana search bar, nothing happens again.  Do you know a trick to restore the menu?  Is it something to uninstall or to install to have again the menu working?  It's not fun to navigate into Explorer every time I need to launch software!


I am new in ubuntu, i have installed a large set of themes in ubuntu, i have also installed advanced-system-settings but when i want to change theme in advaced system settings , themes are not in drop down list?


I've added this function to my .bashrc file:  SSH(){     ssh -X -o PasswordAuthentication=yes root@10.222.22.$* }   and while trying to perform for ex. SSH 101 I get message:  SSH: command not found


my server yesterday started sending thousands of spam emails. I blocked it adding default_transport=No transport to the postfix main.cf. But now of course I can't send legit emails as well.  I have 10+ websites in my Centos Server, using Nginx. I went via FTP to see if there were new strange files or recently edited (checking the dates). I couldn't find anything suspicious.   I want to track the source of the script sending emails - they are being sent using the generic email address configured in the server.  In my php.ini I added:  mail.log = /var/log/phpmail.log   And I created the file phpmail.log via touch on /var/log/ and I restarted the server using the command systemctl restart php-fpm  The file phpmail.log is not populating, still 0KB. Now it has the following righs:  -rwxrwxrwx  1 apache apache       0 Aug 10 12:47 phpmail.log   But I tried to give him nginx.nginx, root, root, web.web, but nothing seems to work. (of course after each chmod change I restarted once again php-fpm, and tried to send emails using for example the mail() contact form on my website).  And I tried also to make this file populate before adding default_transport=No transport to main.cf.  Not sure if it's useful for you, but mailq is full of mails in the queue.  Do you have any idea what is wrong with the file phpmail.log and why it's not populating, and/or how to find the root cause that is preventing it to populate?


Evaluate: $\lim_{y\to x} \dfrac {y\sec y - x\sec x}{y-x}$  My Attempt: $$=\lim_{y\to x} \dfrac {y\sec y - x\sec x}{y-x}$$ $$=\lim_{y\to x} \dfrac {y\cos x-x\cos y}{\cos x\cos y \cdot (y-x)}$$


Cutting a square out of the center of an image

There may already be answers for what I need to know, however, I cannot seem to make work what answers I do find.  So, I will ask anyways.  I have an image that is floral in design.  I have it saved as both a png and as a jpeg.  What I am wanting to do with it is make it into a picture frame by cutting out the center of it, leaving about an inch or so all around the edge.  I want the hole I cut out to be transparent so that I can either slide another pic underneath it or put it over the top of another pic.  When I am done, I will save it as a png.  I can use Adobe Illustrator, or Photoshop.  I really need some help please.


Easy way to remove all overlay behavior from my beamer presentation?

When one makes a beamer presentation with many overlays (as for a lecture), one ends up with a pdf with many pages that is hard to read through. It would make sense that someone had come up with a quick and easy way to remove all overlay behavior from a document, to make a pdf that can be quickly perused.  In the past I have tried to do some clever use of "find and replace". But that can get tricky.


How can I uninstall Ubuntu without Dual booting

It's an old computer so I decided I'd mess around with Ubuntu and try it out, but now I have a use for it and would prefer it be windows. However, since updating last week Ubuntu has overwritten my ability to boot from a CD and I can't figure out a way to get rid of it.


If I immerse a coin in a cup of water, help me define the forces acting on it

So the coin is hanging in an equilibrium position midway in the water filled cup, concerning the force acting on the upper face of the coin, I define it as F=mg where m is the weight of the water directly above the upper face of the coin and g is the present gravitational field, if I divide and multiply by V and then divide by A to get an expression for the total pressure affecting the upper face of the coin, I get P=Dgh, where V is the volume of water directly above the coin and A is the surface area of the coin (not the cup) and h is the height of water affecting the coin and D is the density of water. What am I struggling with : -The two horizontal forces affecting the lateral surface of the coin, they aren't any related to P=Dgh as the gravitational field is vertical, however my book disagrees with me.


This is kind of a long story, but I'll try to keep it simple and to the point.  My hard drive with Windows 10 on it broke. I'm not sure why, and the actual hardware is fine, but the installation was beyond repair. I was trading hard disks between computers as I was upgrading to a new machine, and must have done something wrong that caused it to throw a fatal fit. Whoops.   In any case, I could boot of a live USB, but installing CentOS from a UEFI bootable didn't work (said something about not being able to activate the port). Then I remembered all the Linux distros I had lying around which I burned on disks a few years ago. I popped in the Ubuntu disk, went through the installation process and everything was fine. Almost everything.  The trouble is, I'm on version 17.10, and the software updater isn't pushing any new system updates to me. Whenever I look for packages in the terminal, it can't find them. I don't know if all my problems will be solved by updating to the latest version, but it's a start.  What should I do next?  Thanks!  P.S. I'm connected to the internet via cord and I can also access it wirelessly.


How to identify "naturally" two subspaces?

I am self-studying  Hoffman and Kunze's book Linear Algebra. This is exercise $1$ from page $111$.  If $W$ is a subset of a vector space $V$, we define $W^{0}=\{f\in V^{\star}|f(w)=0 \operatorname{for all}w\in W\}.$     Let $n$ be a positive integer and $\mathbb{F}$ be a field. Let $W$ be   a set of all vectors $(x_{1},\ldots,x_{n})$ in $\mathbb{F}^{n}$ such   that $x_{1}+\cdots+x_{n}=0$.      a) Prove that $W^{0}$ consists of all linear functionals $f$ of the   form $$f(x_{1},\ldots,x_{n})=c(\sum_{j=1}^{n}x_{j}).$$      b) Show that the dual space $W^{\star}$ of $W$ can be "naturally"   identified with the linear functionals   $$f(x_{1},\ldots,x_{n})=c_{1}x_{1}+\cdots+c_{n}x_{n}$$ on   $\mathbb{F}^{n}$ which satisfy $c_{1}+\cdots+c_{n}=0$.   My approach for part a) First, we note that $e_{i}-e_{j}\in W$ for all $i,j\in\{1,2,\ldots,n\}$. If $f\in W^{0},$ then we have $f(e_{i})-f(e_{j})=f(e_{i}-e_{j})=0.$ Therefore $f(e_{i})=f(e_{j})$ and we have $f(e_{i})=c$, for all $i\in \{1,2,\ldots,n\}$, where $c$ is a constant. Therefore, if $w=(x_{1},\ldots,x_{n})\in W$, then $f(x_{1},\ldots,x_{n})=c(\sum_{j=1}^{n}x_{j}).$ The converse is easy.   I was not able to solve the part b).


I have the su executable with the following permissions:  bash-4.2# ls -la /bin/su -rws--s--- 1 root wheel 59930 Sep 14  2012 ./su   When I am logged in as a user, not in the wheel group and try to run su, I get an error, which is correct:  bash-4.2$ su bash: /bin/su: Permission denied   After that I add this user to wheel group from root:  bash-4.2# usermod -a -G wheel user   But for the same terminal session I still can't run su:  bash-4.2$ su bash: /bin/su: Permission denied   For the new sessions I can run su. How to allow to run su instantly after I added the user to the appropriate group?


Stats:   Android 4.1.2 Samsung Galaxy S3 LTE (TouchViz) Chrome browser 27.0.1453.90   I posted a question recently in ELL, and when I looked at it using my smartphone browser, I noticed that text that is supposed to be in italics is in regular font. This negates the effect I wish to achieve by using italics for readers using their mobile phones.  Mobile phone browsers are fully capable of displaying italic text, so I'm not sure what the issue is. I remember noticing this several months ago, but it's still there and has not been fixed yet.  Please let me know if you need test cases, screenshots or any other additional info.


Wrong result when calculating floats in Eclipse

Eclipse gives the wrong result when trying to calculate the sum of two floats. In my code, there are 2 float variables: float from = 0.025 and float to = 1. Then result has double variable: double value = 7 * from / to. Eclipse compiler shows: value = 0.174999997019767760 In excel calculator, this result was value = 0.175  How can I solve this an issue?


Close button in image upload dialog is not tabbable and does nothing on user profile and in tag wikis

When editing a profile’s “About me” section, or a tag wiki, and hitting CtrlG, or clicking the “Image” button from the formatting bar to insert an image, the Imgur upload modal dialog will appear. The same modal will also appear when uploading a profile picture. This is different from questions and answers where an uploader overlay bar (technically referred to as inline-dialog) appears. This modal dialog has an × button for closing, but it does nothing when clicked. I also can’t try tabbing to it and hit Enter, because it’s a regular <div> with no tabindex attribute, so it’s not tabbable and not an interactive element. (After manually inserting a tabindex and pressing Enter, it also did nothing, of course.)  There are no errors produced in the console of any browser. It doesn’t even seem to have any event listener bound to it. Pressing the Esc key or clicking outside of the modal dialog will dismiss the dialog, but the × button is currently useless. An obvious possible  would be to unify all Imgur upload dialogs to the way they appear on questions and answers, as an inline-dialog. But for the profile picture uploader, this dialog doesn’t have an obvious alternative, so in this instance, it’s necessary to redesign the close button so that it acts as a normal button (interactive element, tabbable) and closes the modal popup.  Related   and  — showing this modal in action; closing it used to work.  — for an older dialog design.


What's the best way to get a 5.5KVrms (7,777V peak) full-wave AC signal at 60Hz strong enough to drive two 8-stage CW multipliers at 150pF per capacitor?  Image for reference:   Not a duplicate of "how to make a 120VAC power supply."


$\mathbb{Z}_p$ with $p$ prime is integral domain

I was trying to solve some exercise from my abstract algebra course, and at some point, I assumed $\mathbb{Z}/2\mathbb{Z} \cong \mathbb{Z}_2$ is an integral domain, because I thought to remember that $\mathbb{Z}_p$ is integral domain iif $p$ is a prime number. Am I right? If I am, how can I prove it to add it to my execise? If not, could you give me a counter example? Any help will be appreciated, thanks in advance.


Estimate of analytic function in a unit disk

Suppose $f$ is analytic on an neighborhood of the closed unit disk and $|f| \le a$ on the upper unit semicircle, $|f| \le b$ on the lower unit semicircle. Show that $|f(0)| \le \sqrt{ab}$.  My idea: By Cauchy's integral formula, $\int_{|z|=1} \frac{f(z)}{z} dz = 2\pi i f(0)$. Write $z = e^{i\theta}$, we also have $$ \Big\lvert\int_{|z|=1} \frac{f(z)}{z}\, dz \Big\rvert = \Big\lvert i \int_{\theta = 0}^{2\pi} f(e^{i\theta})\, d\theta\Big\rvert \le \pi (a + b) $$ so $|f(0)| \le \frac{a + b}{2}$.  But here we want a better estimate $\sqrt{ab}$. Any hint?


I want to connect via SSH from Windows Machine to Ubuntu

I want to create a SSH tunnel but I dont know how to identify my Windows 7 machine.  In the command below, what do I have to put replace me@win7_machine with in order for it to work? Is it my username@IP_address? username@pcname?    ssh -R 12345:localhost:3306 me@win7_machine -N


Let $a$ and $b$ be positive interger such that $a|b^2$ , $b^2|a^3$ , $a^3|b^4$ , $b^4| a^5$ ... Prove that $a=b$.  Here how I tried to do it, I think it isn't the best way to approach it but anyway I failed in proving it:  EDIT: Let $a = p_1 ^{a_1} p_2 ^{a_2}  ... p_k ^{a_k}$ and $b=  p_1 ^{b_1} p_2 ^{b_2}  ... p_k ^{b_k}$ and $a_i, b_i \geq 0$ for $i$, $ 0 \leq i \leq k$. Then for a specific prime $p_i$, $a_i \leq 2b_i$, $2b_i \leq 3a_i$ , $3a_i \leq 4b_i$ and $4b_i \leq  5a_i$.... I tried to get some information from that but didn't get anything.  This question has been marked as a duplicate but it is in fact different, or maybe that's what I can directly deduce from the conditions. Just look carefully at the titles to realise that they are different.


On Macbookpro CPU accountsd process started showing 400% usage

I was on Catalina 10.15.6 on MAcBook Pro yesterday and my fan started making too much noise and the battery was down to 7% from 90% in 20 minutes. I closed all the apps and still it is the case. Later looking at few similar posts I tried the update to 10.15.7 which was popping up on systems. The build is 19H2. The issue has not gone. Tried to connect to apple support but didn't get any useful answers. Can some one please help.


what is invertible elements of polynomial ring $k[x_1,...,x_n]$  ? for case  $n=1$ we have $k[x_1]$ and $$ p(x)=a_{0}+a_{1} x+\ldots a_{n} x^{n} $$ then $p(x)$ is invertible element such that $a_{0}$ is a unit in $R,$ and the remaining coefficients $a_{1}, \ldots, a_{n}$ are nilpotent elements. ( $k$ is a field)


Can't switch between sites while on my mod site on new mobile web

When I'm on my mod site I have my diamond dropdown:    But on Meta.SE and other sites, I have the StackBurger:    This doesn't show on my mod site, so I can't switch between sites easily.


is compactness equivalent to limit point compactness?

I would like to know if compactness is equivalent to limit point compactness in general for any topology. If so I'd like to see a proof, other wise I'd like to see a counter example. I am curious about this because I want to get an intuition for compactness, limit point compactness makes intuitive sense to me as a way of determining if you can "escape" the space by getting ever closer to a point "outside" the space, however the idea of open covers and open sub covers seem to come out of no where, I'd like to see an example where there 2 definitions differ so that hopefully I can see the need for the compactness definition that we use.  This is not a duplicate of limit point compactness implies compactness as I am not just asking about the first direction of implication but rather both directions of implication, I also want to know if compactness implies limit point compactness.


Executing command line programs from within python

I'm building a web application that will is going to manipulate (pad, mix, merge etc) sound files and I've found that  does exactly what I want. Sox is a linux command line program and I'm feeling a little uncomfortable with having the python web app starting new sox processes on my server on a per request basis.   Example:  import os os.system('sox input.wav -b 24 output.aiff rate -v -L -b 90 48k')   This whole setup seems a little unstable to me.  So my question is, what's the best practice for running command line programs from within  a python (or any scripting language) web app?  Message queues would be one thing to implement in order to get around the whole request response cycle. But is there other ways to make these things more elegant?


Creating extent indicator in Data View of ArcMap?

I know how to create an extent indicator in Layout View, but I have no idea how to create one for Data View. I have 25 bookmarks created for Data View and what I need to do is to display all of them in Data View. I work in ArcMap 10.3.


Txfonts causes misalignment of symbols in an equation block

I have encountered issue with symbols alignment (&) within the matrix in an equation block - are on the each other in one row. Issue is most likely associated with txfonts package. Matrix's symbols are well-aligned without the package, however I would like to keep it due to roman fonts it provides. Example using amsmath with txfonts: \documentclass[12pt, oneside, openany, a4paper]{report} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{amsmath} \usepackage{txfonts} \begin{document} \chapter{...} Minimalizacja tranzystorów i konieczność brania efektów kwantowych pod uwagę. \section{...} \begin{equation}     X = \begin{bmatrix}         a & b & c \\         c & d & d \\         e & f & g \\     \end{bmatrix} \end{equation} \end{document}  The output is:  How can use txfonts but with a proper alignment for example for amsmath matrices?


Proving $\mathbb{Z}[\sqrt {10}]$ is not a UFD

I am wondering how to show that $\mathbb{Z}[\sqrt {10}]$ is not a UFD.    My only idea is to show that there are two factorizations of $10$, say, $ab, uv$ such that $a$ is not a unit times $u$ or $v$. In this ring $10=2\cdot5=\sqrt {10}\cdot \sqrt {10}$, so it suffices to show $2$ is not a unit times $\sqrt {10}$. Suppose $2=\sqrt {10}(a+b\sqrt{10})=a\sqrt{10}+10b$. Then $a=0$ since $\sqrt{10}$ is not rational. So $10b=2$, which has no integer solutions. So $\mathbb{Z}[\sqrt {10}]$ is not a UFD.  Is my reasoning correct? What are the flaws?


What does Windows 10 write to my drive before going to sleep?

I noticed that my Windows 10 laptop takes around 6 seconds to go to sleep, and during these six seconds the SSD's activity LED is on. I imagine that Windows is writing something on the SSD before going to sleep.  I remember my Linux systems going to sleep instantly when I pressed the sleep button, which makes me wonder if I can do the same on Windows.  Given that Hybrid Sleep is disabled, what does Windows do with my drive before sleeping, and is it necessary ?


Python Astronomy Censored Data in Lifelines

I am trying to find a correlation between a given data set containing redshifts and turnover frequencies (I have a list of 320 galaxies, and the redshift and turnover frequency (a turnover frequency is the frequency of the peak in the radio spectrum) is given for each (so have 320 data points)), but a third of the turnover frequency measurements are upper limits. I am looking at using the lifelines package (depends on pandas) to analyse this, but so far I have only seen tutorials that consider only one data set (eg. age at death).  So far I have only been able to include the uncensored measurements in fitting a trendline.     The red points are upper limits. As you can see, the correlation is extremely weak.  Can lifelines be used to find relationships between two variables like as described above?   If so, could I use the KaplanMeierEstimator function?  If not, does anyone have a suggestion for a survival analysis package for python that can analyse my data? (I know of Rpy2, but have had trouble installing)


sending bulk email with different names in reply address and spam filtering

I have a web service where I send out bulk email on behalf of customers.  The sending email address is the same for all customers, something like noreply@mycompany.com.  When sending out the email on behalf of a customer, I'd like to specify the name of the customer in the email address.    For example, when I send email for ACME Inc., I'd like the the email address to look like:   ACME Inc. <noreply@mycompany.com>   But I send email on behalf of Globex Corp., I'd like the email address to look like:  Globex Corp. <noreply@mycompany.com>   I know how to do this, but would using different names with the same sending email address raise any flags with spam filters or email blacklist sites?  Email deliverability is very important.


Stack Exchange's heavy reliance on external scripts

I dislike running third-party scripts in my browser and have disabled these generally.   I can enable them on an exceptional basis, but it strikes me that Stack Exchange has an unusually heavy reliance on JavaScript code that's hosted externally, that is, on other sites.  In particular, much of Stack Exchange's functionality is dependent on scripts hosted at googleapis.com (although there are several other locations called out to).   Copied from , the following functionality is dependent on external sites:   Adding comments. Voting. Controls (image, code buttons, etc.) missing from message posting form and the preview does not appear. Automatic recognition that you are 'not a bot'. Notify daily of new answers option. ...   I find this annoying - I consider it to be a (mild) security/privacy problem.  But, also, it must cause problems with Stack Exchange's proper function. If such an external site is down: much of Stack Exchange's functionality will fail.  Can this be changed?


When are quantities outside of the real numbers considered equal, and when do they exist?

From the context of the real numbers we know that the square root of $-1$ is not a real number. Because of this the historical way we approach this is that the concept of complex numbers were created to give meaning to the nonexistence of $\sqrt{-1} = i$ and study the potential implications of such a value. We even knew beforehand how the square root of $-1$ as it existed as a concept. It was merely that it did not exist as an intermediate vale.  When that set was created, certain properties were different from the set of real numbers and other properties (such as ordering) ceased to exist. If some superset of the complex plane were created to give meaning to another currently 'nonexistent' operation, what algebraic properties would we expect to retain? For instance, if one wanted to extend nonexsistent limits into being for which the one sided limits exist, would you only assume them equal to themselves or would you make them equal to limits with similar shapes around the point? Of course that is a hypothetical example, not to be taken as an actual request. The details of that would depend on whether geometric equivalence was the equalizing factor or the sequence used to compute the limit.  I know I have written two questions here. So to summarize:  First: what extensions upon real numbers currently exist other than the complex plane?  Second: How would one go about creating a new extension, and how do people usually work out their properties aside from creative thinking? Is there a formal method that can be used to determine the properties of an extension coming from attempting to give meaning to an intermediate value that is "undefined"?  Note: I couldn't come up with the proper tag so some guidance would be appreciated. I was thinking the tag "equality" or "extensions upon real numbers" or "monexistence" would be good, but those are not available.


How do I make combinations between the values in lists in python?


After Gankyou in Joshiraku removes her glasses, her eyes change to '3' characters.    Marii then exclaims:    I understand Nobita is a character in Doraemon, but I haven't found any information online either of pictures where Nobita has his glasses off, or any references to a "Nobita face".  Can someone explain this joke further?


I tried to shrink my Windows Bootcamp partition using third-party software which led to my Macintosh HD partition missing from startup options. Unfortunately I don't have a recent backup for the whole drive to restore from. If I try to reinstall macOS from scratch it doesn't see the partition either.    Disk utility sees it but it's greyed out and is being shown as Unmounted without the option to mount it back.    Is there a way to fix this without wiping out the whole drive and reinstalling everything from scratch?


Why does the letter 'y' appear randomly in front of words in Renaissance poetry?

In a work by Thomas Watson (1555-1592), there is a line as follows: Her dainty forehead from the sun ykept.   Why does y appear in front of kept?  I have seen this odd use of y in other poems in the collection I am reading: Poetry of the English Renaissance, by Hebel and Hudson.


'Upgraded' to Windows 10 on dual boot, and can't boot to Ubuntu partition

I recently updated my windows 7 to 10, and destroyed grub in the process. I ran Boot-Repair on a live CD and managed to get the Windows Partition back. However grub still doesn't come up for me.   The boot-repair url I received was .   Edit:  Oldfred helped me figure out the problem. I didn't really understand how the partition worked. The extended partition wraps around both the linux and swap partition, but for some reason the linux partition was not showing up. I booted to a live disk and ran parted rescue:  sudo parted /dev/sda unit s print //this printed the current partition table  sudo parted unit s rescue Start? //Here I entered in 1 sector after the extended partition End? //Here I entered in 1 sector before the swap parition   After that I ran boot-repair again and was able to restore grub back in place! Everything is working great now. Hopefully this post can help someone else!


I used an answer from  and the links that were provided in the answer. Now, I am presenting the project for which I used the answer, and I would like to give proper attribution. From what I see, Crypto Stack Exchange does not give an option to cite the answer. How does one cite an answer in MLA format?  Edit  I am submitting my project for a science fair, and there is no one that I can ask about citations.


Beamer: make some slides inaccessible for usual navigation

Is there a way to make some slides inaccessible for basic forward navigation controls (left arrow and mouse click)? Motivation: I want these slides to reside at the end of my presentation and be accessible only via hyperlinks. According to  this might be possible w/ \lecture and \includeonlylecture but this accomplished nothing (a MWE below). Another solution would be to somehow† specify the current slide to be the next one shown (and put the reserved stuff after it), but I don't know if this is possible. A third way would be to make the reserved slides be partly like the last and partly new, and switch the shown/hidden parts depending on whether a link is clicked or not. As I'm running out of time in preparing the presentation, I will not start experimenting w/ any of this  † E.g. by a label or option  \documentclass{beamer} \includeonlylecture{wee1}  \begin{document}  \lecture{Vector Spaces}{wee1} \frame{ju} \frame{ju0}  \lecture{Scalar Products}{wee2} \frame{nu} \frame{nu0}  \end{document}


How to seperate nodes that have melted together in a Latex tree?

I am a beginner, making trees in Latex, but some of my nodes keep melting together.   They are not supposed to be linked in anyway, but I cannot find out what I am doing wrong.    Can anybody please help me?


Should I use cascaded regulators, or connect them all to the same input?

For a particular design, I need to take an unregulated voltage from a battery and regulate 5 different DC voltages from it. What's worse is that I need step-up and step-down converters. What's even worse is that some voltages need more current than others.  Note: To clarify the question, I've given the specific voltages that I need. However, keep in mind that I'm wondering what to do in general, not just this specific case.  The battery voltage is 11.1 V, which drops as it discharges. I need to create:   15 V 12 V 5.5 V 5.0 V 3.3 V   The 12 V level needs to run at least 1 A, and the three lowest need to run about 200 mA each. The 15 V level doesn't use more than 50 mA.  So this is my question: would it be better to go from the battery to 15 V to 12 V to 5.5 V to 5.0 V to 3.3 V, or would it be better to just connect all 5 regulators directly to the battery?


How many outlets can you have on one 15 amp circuit?

In my rebuilding project I have counted 18 outlets and lights on one bedroom circuit that travels through 3 rooms. Is that ok?


How do I fix a command generated by MCStacker?

I'm trying to make a map with a death-checker. I'm not a command pro, so I used MCStacker to generate a command. The below command is a function that I generated: give @p chain_command_block{display:{Name:'{"text":"Consequence block","color":"blue","bold":true}'},Enchantments:[{}],BlockEntityTag:{Command:"execute if score @p Deaths matches 10 run title @p title {"text":"this is a test","color":"#6BFF93","bold":true}",auto:1b}} 1  This will give me a command block, which will check if I'm at 10 deaths and if so, will execute a title. But for some reason it doesn't work. Instead, the command generator wants me to make the code like this: run title @p title {"}} 1  But if I do that, my command doesn't work anymore. I've been stuck with it for a few hours now. How can I get this command to work? I'd prefer solutions that fix the issue in MCStacker so I can regenerate the command. My screen with the commands:  The error in Minecraft log:


How do I convert a diagonal line pattern in my *.psd to a Photoshop pattern?

In my psd from designer I have a background like in the red rectangle.    This pattern doesn't show up in any Photoshop patterns. (maybe it's inner psd container)  How could I fetch a small rectangle from Photoshop and use it as a css background, having it repeat seamlessly without any bugs or borders etc.?  How do I fetch repeated content for a background from a .psd layout?


Recommended Samples and other settings to remove fireflies?

I was rendering this single image and wanted to get the best quality render with proper lighting and least (If possible, no) fireflies. I am currently rendering with these settings.  Filter Glossy 0.5  Refractive Caustics Off  Reflective Caustics On  Clamp Direct 0  Clamp Indirect 3  GPU Nvidia GeForce 840m  Tile Size 64x64  Samples 200  Estimated Time per Frame 30 minutes   Is there any way to remove the fireflies further. If so please do tell me.


Compute integral closure of $F[x,y,z]/(x^2-y^2z)$.

I want to compute integral closure of $R:=F[x,y,z]/(x^2-y^2z)$. Let $S$ the integral closure. I have proved that $\frac{\bar x}{\bar y}$ and $\bar y$ are integral over $R$ and that $\{\bar y,\frac{\bar x}{\bar y}\}$ is a transcendence basis of $\text{Frac}(R)$. My questions are the following one :  Q1) Why $S\supset F[\bar y,\frac{\bar x}{\bar y}]$ ? I agree that if $S\supset R[\bar y,\frac{\bar x}{\bar y}]\subset S$, but why $F[\bar y,\frac{\bar x}{\bar y}]\subset S$ ?  Q2) Why $$\text{trdeg}_F(\text{Frac}(R))\leq \text{trdeg}_F(\text{Frac}(F[\bar y,\frac{\bar x}{\bar y}])) \ \ ?$$  With those answer, I can conclude.


A sequence in $L^p$ which converges weakly to zero but not strongly.

First Problem: Let $\{f_k\}$ be a sequence on $L^p(\mathbb{R})$ for $p \in [1,\infty)$ of the form $f_k (x) = k^{1/p} g(kx)$ for a fixed $g \in L^p(\mathbb{R})$. Show that $f_k \to 0$ weakly but $f_k$ does not converge strongly.    Idea:  We want to show that $\int_{\mathbb{R}} k^{1/p} g(kx) \phi(x) dx \to 0$ as $k \to \infty$ where we can without loss of generality assume that $\phi$ is a continuous compactly supported function (by density of $C_0(\mathbb{R}) \subset L^q (\mathbb{R})$ where $\frac{1}{p} + \frac{1}{q} = 1$). Then we have  \begin{align*} \int_{\mathbb{R}} k^{1/p} g(kx) \phi(x) dx \leq k^{1/p} \max_{x \in \mathbb{R}} {[\phi(x)]} \int_{\mathbb{R}} g(kx) dx. \end{align*} Now I am unsure what to do. My guess is that since $g \in L^p(\mathbb{R}) \implies g \in L^1 (\mathbb{R})$, by the second fundamental theorem of calculus (for Lebesgue integrable functions) we can define \begin{align*} G(x) := \int_{[-\infty, x]} g(x) dx \end{align*} which is continuous and almost-everywhere differentiable with $G'(x) = g(x)$. In other words, we can compute the antiderivative of $g(kx)$ by using the reverse chain rule ($u$ substitution), which gives us \begin{align*} k^{1/p} \max_{x \in \mathbb{R}} {[\phi(x)]} \int_{\mathbb{R}} g(kx) dx = \frac{k^{1/p} \max_{x \in \mathbb{R}} {[\phi(x)]}}{k} \int_{\mathbb{R}} g(u) du \to 0 \text{ as } k \to \infty. \end{align*} My main concern is my integral  is over $\mathbb{R}$ instead of $[-\infty, x]$, but is this a big deal? It seems that one can just split $\int_{\mathbb{R}} = G_1(x) + G_2 (x)$ where $G_1(x) = G(x)$ and $G_2(x) = \int_{[x, + \infty]} g(x) dx$ with $G_2'(x) = g(x)$ by the fundamental theorem of calculus again.   To show that $f_k$ does not converge strongly,just set $g(x) = 1_{E}(x)$ for a measurable set $E$ so that $f_k(x) = k^{1/p} 1_{E}(x)$ does not go to zero as $k \to \infty$.    Second problem: Let $\{f_k\}$ be a sequence on $L^p(\mathbb{R})$ for $p \in [1,\infty)$ of the form $f_k (x) = g(k + x)$ for a fixed $g \in L^p(\mathbb{R})$. Show that $f_k \to 0$ weakly but $f_k$ does not converge strongly.    Idea: By the same logic as before,  \begin{align*} \int_{\mathbb{R}} g(k + x) \phi(x) dx \leq \max_{x \in \mathbb{R}}[\phi(x)] \int_{\mathbb{R}} g(k + x) dx, \end{align*} where $\phi$ is a continuous compactly supported function. The problem is doing $u$-substitution doesn't really do anything. My gut feeling tells me to approximate $g$ using continuous compactly supported functions, so that the shift sideways of g $g(k + x)$ goes to a place where $g = 0$.


MacBook Pro locked with Find My Mac and won't let me boot

I was playing around with the Find My Mac iPhone app (just testing it out) and hit the "lock" option. My MacBook Pro is now locked and I have no place to enter the 4 digit PIN.  When I start it, it shows the Apple logo with a loading circle and it shuts down. If I start whilst holding alt it asks for the PIN, which I enter, then it shows three partitions: Macintosh HD, Recovery & Windows. If I select Windows it works perfectly, but the two others show the problem with the Apple logo and loading circle before it shuts down.


I am involved in a bigger university mobile application project and my task is to design and develop a mobile module regarding map and location-based services in a native Android application.   Shortly my part of app should display different kind of info on a georeferenced map (Google Map or Openstreetmap) based on Oracle data:   Shortest path to reach a certain event from a certain location Different layers with domain information to the event (like parking places around it, bus lines ecc. ) GetFeatureInfo option   I am new in this kind of topic and I would like to ask you an architectural question regarding it.  I thought about using Geoserver to define layers, styles, datasets etc., and WMS protocol to generate the map over a website using  HTML 5, OpenLayers, and jQuery-mobile.  But how can I accomplish this in a native android app?   Building a webpage where I display the map using HTML 5, OpenLayers and jQuery-mobile to interact with Geoserver and then using the Webviews in Android to display the webpage in my app? Would be this a possible solution? Possible drawbacks?  What are the alternatives using Geoserver?


Can the listings package highlight by regexp?

I'm trying to typeset SuperCollider code using the listings package.  Any "freestanding" identifiers that begin with a capital letter are class names, and should be highlighted; by "freestanding", I mean outside of strings or comments. I would be tickled pink if listings could let you define identifiers in terms of regexp, e.g. [A-Z][A-Za-z0-9_]* but the manual doesn't suggests that as a possibility.  SuperCollider has some 2300 classes... I really don't relish listing all of them literally in my preamble. I guess I could extract them by hand for each individual listing, but I'd rather not have to.  Is there a way to do this without a really massive morekeywords expression? (Perhaps using another package?)  Sample SuperCollider code:  p.clear;  ~grains.addSpec(\tfreq, [1, 40, \exp]); ~grains.addSpec(\overlap, [0.1, 10, \exp]); ~grains.addSpec(\pos, [0, b.duration]);  // 3.43 is nice! ~grains.addSpec(\rate, [0.5, 2, \exp]); ~grains = { |tfreq = 25, overlap = 6, pan = 0, amp = 0.2, pos = 3.43,    rate = 1|    var trig = Impulse.ar(tfreq);    TGrains.ar(2, trig, b, rate, pos, overlap / tfreq, pan, amp) }; ~grains.play;   Impulse and TGrains should be highlighted in blue. I have dozens of other listings using different capitalized keywords.


Is the question: 'Is our universe the inside of a black hole?' meaningful?

By meaningful I mean experimentally falsifiable.


How to remove Polaris Office on HTC phones?

I have Polaris Office installed on my HTC Sense 6, but I cannot delete or find it on my installed apps, Play Store, and even Device Administrators. Though, I can run the app and use it.  How am I going to delete it?


How to automatically feed two arguments to program after startup?

I have this following script which works fine on ubuntu for starting and creating a new table for MySQL database:   echo "CREATE DATABASE database_name" | mysql -u root -p   After this command is executed MySQL asks for password.  The only problem is that I want to do this on vagrant provision bash script, so I have to automate the process of entering the password. I basically have to give a single line of input to the MySQL program like this:  Enter password: password_goes_here   How do I combine the process of entering the database creation command and the password as text to the program?


Bounding Column's Values w/ Foreign Key Relationship?

I'm creating a new table that contains a 'user'. So far, the table looks like:  create table users(   id primary key,   code varchar )   Currently, the "universe" of codes consists of: A or B.  Is it worthwhile, from a DB Design point of view, to create a codes table that contains all known codes?  create table codes(   value varchar, -- with unique constraint   description varchar )   Then, I could update my users table's code column to have a foreign key relationship to the codes.table column.  Does this change seem to be useful for my above case?


Minority class misclassification penalty in logistic regression (sklearn)

I am facing the problem of class imbalance in my dataset. Due to some constraints, I cannot use any other classifier than logistic regression in sklearn.   Given that, Can I impose a penalty for misclassification of the minority class to improve the model?


LibreOffice compares numbers incorrectly

Just see this screenshot. Why does it return TRUE instead of False? What is going wrong here?    Sanity check:


What is the equivalent of ReDimStatement in c#?

In vb.net I've this code block:  Public Sub AddItem(Text As String, Optional Left As Integer = 0, Optional Header As Boolean = False)     Dim Item As ListItem     ReDim Item.Text(0)     Item.Text(0).Text = Text     Item.Text(0).Left = Left     Item.Header = Header     LstItems.Add(Item) End Sub   UPDATE: ListItem  Public Structure ListItem     Dim Text() As ListText     Dim Header As Boolean End Structure   this code allow me to add an item to a list, ReDim allocate the storage space for an array variable in vb.net, in c# what is the equivalent of this code? I also tried to convert it on  without success.


Does the cost function for logistic regression use log base 10 or natural logarithm?

I'm trying to implement the cost function to estimate the SVM models I've trained with scikit-learn for a classification problem.  Unfortunately, from my course (Andrew Ng's Coursera course on Machine Learning), I have not understood whether the cost function should use 10-based logarithm, or the natural logarithm.  Here's the formula:   Could I use both logarithm functions? Does it have any influence? Which is more appropriate in general?


How to enable animation of linked rigged object

I made a simple stickman with joints. Works fine. Saved it as stickman.blend. I grouped CTRL+G the stickman+armature.  I made a new scene.blend file. I linked the group from the stickman with ctrl+alt+O into the scene. It is visible with all joints. So far so good. But I can not get it into Posemode. I think this is because it is "hard" linked to the stickman.blend. So I need a tip, how I can animate this in a new scene.  I don't want to simply append it to the scene, because when I make changes to the stickman they should also appear in my scene.  So for such a low level question. But after google/youtube I was out of an idea.  thanks for your help in advance


I keep getting this error when I try to push: The "path" argument must be of type string. Received type undefined.


Let G be a group of order 2n with n being an odd integer. Prove that G has a normal subgroup of order n.

I have been trying to work this problem out for a bit and am stuck.  Does anybody have any ideas how to proceed or solve this?  I think this has something to do with rings and fields but I can't seem to find the connection.    EDIT: I know the other proof listed as a duplicate here, but it uses Cauchy's Theorem and  we are not allowed to use that because we skipped that chapter.


Whenever I read about IFS it was always in the context of read (or at least thus I understood). Is IFS used for anything else than read shell-builtin?


I have a custom object 'interview outcome' that is used to sent automatic email via process builder to update the candidate about the interview outcome. I want a field 'Attachment' so that the admin can select a file and attach it to the record during creation and also sent it via email. The file will be different for each candidate. I could not see any data type in Salesforce that can support file attachments. Is there any way to achieve this?


Using Gram-Schmidt to compute the cross product of $3$ vectors in $\Bbb R^4$

I want to ask about vector multiplication (cross product) in $4$-d. I heard that Gram-Schmidt process is involved but I am not sure how the process is involved.  The multiplication involves $3$ vectors with $4$ components.  Please someone help.


Can I pick up and drop a person in one turn?

I am playing a level 6 Barbarian (I have 2 attacks). I picked up a person as one attack and walked him over to a well, and with my second attack I want to drop him.  Can I do that all in one turn?   To clarify: my PC is a Loxodon with 50 feet of movement.  I "grappled" my opponent with my trunk.  I was right in front of him, took him, and went to the well 20 feet away.


I am planning on ordering a panel with four different designs on it. Two were made in Altium, while the other two were made in Eagle.  Altium has a great tool for panelizing boards designed in it, but I don't believe it can put designs from other programs on the panel.  How can I panelize these PCBs?


How do I completely remove Ubuntu from my computer?

I completely removed Windows 7 from my computer and installed a full version of Ubuntu on i.e no partition. I just got my Windows recovery disk and driver disk in the mail and I would like to remove Linux completely and re-install Windows.  Problem is the recovery disk will not boot automatically upon starting up.   Any suggestions?


I have a landing page that I'm wanting to get my logo centered. Struggling to figure how to get it exactly in the center and stay there on device scale. I have got the video background to scale accordingly, but I cannot get my logo to go exactly into the center.  Here is a fiddle   shows a black box and in the square I'm wanting to get centered within the landing div.   This is the specific div needing to be sorted out.  .main_logo{     background:#000;     position:relative;     float:left;     width:300px;     height:200px;     z-index:2000;     display: block;     margin: auto; }


Orthonormality and completeness in infinite dimensions: 2 different definitions

In finite dimensional vector spaces, orthonormality is defined as $\langle x_i|x_j \rangle=\delta_{ij}$ and the completeness relation is given simply by $$I = \sum_i |x_i\rangle\langle x_i|.$$  To me, the most obvious extension of this finite dimensional case to infinite dimensions is to keep orthonormality as $\langle x|y \rangle=\delta_{xy}$ (where $x$, $y$ are real), while the completeness relation becomes $$I = \sum_{i=1}^{\infty} |x_i\rangle\langle x_i| = \int |x\rangle\langle x|.\qquad(\ast)$$  Now in quantum mechanics, orthonormality of basis vectors $|x\rangle$ and $|y\rangle$ in an infinite dimensional vector space is usually defined as $\langle x|y \rangle=\delta(x-y)$, while the completeness relation is given by $$I = \int |x\rangle\langle x| dx.$$  It seems to me, however, that my extension of orthonormality and completeness to infinite dimensions is equivalent to the usual extension.  As a demonstration that my version of completeness is consistent with my definition of orthonormality, let $| f\rangle$ be some arbitrary linear combination (integral) of basis vectors $|x\rangle$: $$|f\rangle = \int f(x) |x\rangle dx.$$ Applying my version of the completeness relation to it: \begin{align} \int |x\rangle\langle x|f\rangle &= \int |x\rangle\langle x|\left(\int f(y) |y\rangle dy\right)\\ &= \int\int f(y)|x\rangle\langle x|y\rangle dy\\ &= \int\int f(y)|x\rangle\delta_{xy} dy\\ &= \int f(y)|y\rangle dy\\ &= |f\rangle \end{align} so equation $(\ast)$ does work as the completeness relation.  Is there anything wrong with defining things this way? If not, then why is the usual definition of orthonormality and completeness preferred?


I have a bricked usb stick Kingston DT101 G2. I tried the solutions I found on the net without success. The problem seems to be that the capacity is reported as 0 (and not less than actual as in other questions). (Although I don't know a command to explicitly query the capacity.)  Sticking it in, /dev/sdd appears but /dec/sdd1 does not appear.  gparted/parted/fdisk don't recognize it. e.g.   $ sudo fdisk -l /dev/sdd fdisk: cannot open /dev/sdd: No such file or directory     $ sudo dd count=1 bs=512 if=/dev/zero of=/dev/sdd && sync dd: error writing '/dev/sdd': No space left on device 1+0 records in 0+0 records out 0 bytes copied, 0.000316047 s, 0.0 kB/s     $ ls -l /dev/sdd brw-rw---- 1 root disk 8, 48 Jan 30 13:45 /dev/sdd`     $ sudo xxd -l 10 /dev/sdd $   (i.e. nothing)  $ sudo smartctl -i -d scsi /dev/sdd smartctl 6.5 2016-01-24 r4214 [x86_64-linux-4.4.0-109-generic] (local build) Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Vendor:               GENERIC Product:              USB Mass Storage Revision:             1.00 scsiModePageOffset: response length too short, resp_len=4 offset=4 bd_len=0 scsiModePageOffset: response length too short, resp_len=4 offset=4 bd_len=0 Terminate command early due to bad response to IEC mode page A mandatory SMART command failed: exiting. To continue, add one or more '-T permissive' options.`   [Edit]    sudo lsblk: no mention of sdd.   Output of lsusb -v (relevant portion only) Note that it reports 2GB instead of the actual 16GB.  Bus 001 Device 022: ID 0930:6544 Toshiba Corp. TransMemory-Mini / Kingston DataTraveler 2.0 Stick (2GB) Couldn't open device, some information will be missing Device Descriptor:   bLength                18   bDescriptorType         1   bcdUSB               2.00   bDeviceClass            0 (Defined at Interface level)   bDeviceSubClass         0    bDeviceProtocol         0    bMaxPacketSize0        64   idVendor           0x0930 Toshiba Corp.   idProduct          0x6544 TransMemory-Mini / Kingston DataTraveler 2.0 Stick (2GB)   bcdDevice            1.00   iManufacturer           1    iProduct                2    iSerial                 3    bNumConfigurations      1   Configuration Descriptor:     bLength                 9     bDescriptorType         2     wTotalLength           32     bNumInterfaces          1     bConfigurationValue     1     iConfiguration          0      bmAttributes         0x80       (Bus Powered)     MaxPower              200mA     Interface Descriptor:       bLength                 9       bDescriptorType         4       bInterfaceNumber        0       bAlternateSetting       0       bNumEndpoints           2       bInterfaceClass         8 Mass Storage       bInterfaceSubClass      6 SCSI       bInterfaceProtocol     80 Bulk-Only       iInterface              0        Endpoint Descriptor:     bLength                 7     bDescriptorType         5     bEndpointAddress     0x81  EP 1 IN     bmAttributes            2       Transfer Type            Bulk       Synch Type               None       Usage Type               Data     wMaxPacketSize     0x0200  1x 512 bytes     bInterval             255       Endpoint Descriptor:     bLength                 7     bDescriptorType         5     bEndpointAddress     0x02  EP 2 OUT     bmAttributes            2       Transfer Type            Bulk       Synch Type               None       Usage Type               Data     wMaxPacketSize     0x0200  1x 512 bytes     bInterval             255


Will the effects of light shine through glass?

If I cast light on a small pebble and placed it in a sealed, transparent glass jar would it emit light outside of the jar?  The reason I am asking is because the rules for areas of effects say:     A spell’s effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn’t included in the spell’s area. To block one of these imaginary lines, an obstruction must provide total cover.   That means that the jar (which provides total cover) would prevent anything outside of the jar from being in light's area of effect. So, it seems to me that the rules imply that nothing outside the jar would be illuminated.  This actually does have potential mechanical implications in the game as can be seen in this question: .   Am I missing something here or is this just an example of the rules creating a nonsensical effect?


Are all of the basic Unix commands available on all of the distributions of Linux including Ubuntu or are only certain commands inherited by Linux? Also, does GNU have it's own commands or does it include all of the same commands?


On my Lenovo Yoga Pad 2 with Ubuntu 14.04 there is no option to dim the screen when in battery mode.  There is one option "Dim screen to save power" but it doesn't seem to have any effect:    How can I set the brightness to another dim level on battery power in Unity?


How to twist radial vector to make spirals?

I'm trying to create a procedural rainbow spiral in cycles like this:     The reference created by rotating the center vertex with proportional editing on, then assigning material slots to multiple colours. I'd like to have something more adaptable, like controlling number of turns and number of iterations of colours.  My attempt at a procedural texture led me to the radial vector which currently has a simple setup like this:    Which then gives something like this:    I have read related questions from  and  but I'm currently at a loss as to how I could integrate my colour ramp to the nodes given.  Any help would be greatly appreciated, Thank you!


I noticed that I can only perform certain actions such as commenting a finite number of times in a given period of time. Obviously, rate limiting is in place to prevent accidental misuse or intentional abuse of certain features.  Where else is rate limiting applied on Stack Exchange sites, and what are the limits?


How can I download Linux on my Toshiba laptop, where windows 7 just died?

I have two laptops, and one is working fine with windows 7. Thew other just  died, and I decided to try Linux on that. The computer is working, and I can access the boot menu, but it wont start windows anymore. How can I install Linux on that computer? I have no files or apps that I need to keep on that laptop.  Thank you


While proving a universal quantification, we begin by "Let ... in ..." or "Arbitrary choose ..."?

While proving a universal quantification, say $\forall a\in D,~P(x)\rightarrow Q(x)$. I see (at least) two type of people, one begin the proof by  (1) Way 1     Let $a$ in $D$,   (or let $a$ be any element in $D$)      $\cdots\cdots$ (some arguments)      $\therefore P(a)\rightarrow Q(a)$      Since we made no special assumptions on $a$, any $a$ in $D$ also deduce   $P(a)\rightarrow Q(a)$. Thus we have shown that $\forall a\in D,~P(x)\rightarrow Q(x)$. (This is exactly what the U.G. rule says.)   one by: (2) Way 2     Arbitrary choose $a$ in $D$,       $\cdots\cdots$ (some arguments)      $\therefore P(a)\rightarrow Q(a)$      Since what we choose is arbitrary, so every element in $D$ also holds true. (some blur here.. Even I guess whether it is "exactly" a usage of U.G. rule)   I'm not ask for a elementary problem that how to prove a universal quantification. Instead, I'm curious which formulation of such a proof is more proper, logical and formal logical structure.  I think way 2 is somewhat not clear since yes, we had indeed arbitrary chosen a element $a$ in $D$, but someone may intensionally argue that "hey, it is because  you're lucky that you randomly chose the right $a$ at the very begin that makes the predicate true in the set! If you want to show that this is true for any element in the set, you should not have use the word choose in the proof's begin; or at least, you should say at end that since our intermediate steps do not use the special assumption of $a$, so it suits for all elements. But in this way, this becomes slightly complex than way 1, why not just use way 1?"   The reason that way II is valid is somewhat of a meta-level, not indicate by the language itself.


I removed libc6 and now server is broken.  Now no commands work. ls, df nothing but I'm still connected to it on the ssh session. Any help?


How to rename List of Figures and List of Tables?

How do I rename List of Figures into Figures and List of Tables into Tables? (An automatic function in LaTeX)  \listoftables \listoffigures   I used this to create them.  And I'm using   \documentclass[chapterprefix]{scrreprt}


Able to submit answer after question is put on hold

A few minutes ago, I submitted an answer on the question . When the page refreshed, I saw that the question had already been put on hold at 2013-11-25 16:16:02Z, while the answer was submitted at 2013-11-25 16:17:03Z.  I am not sure why this happened. Is it because I had typed in the answer a long time before it was put on hold, and the draft's save time was before the hold time? (I was waiting for the user to reply to my comment before submitting the answer, but got tired of waiting and just hit submit.) Or is it because the version of the page I was on had not registered that the question was on hold?  Either way, I do not think that the answer should have been able to be posted, and I think it is a bug that it did.


I want to move my object with an acceleration in the proper direction.  For example if I have these values:  friction = 0.3; direction = 180; speed = 5;   For making it clear, I need a formula to create a linear acceleration.


Is there any noun in English which changes the first letter in the plural?

Plenty of nouns change the second letter to become plural (man->men, goose->geese) but does anything change its first letter.  I've hunted high and low over the internet, and spent ages browsing the questions at  but I can't find anything.


Inequality involving the integral of vector valued function

Suppose $f :[a,b]\to \mathbb{R}^n$ is given by $f(t)=\langle f_1(t), \ldots, f_n(t)\rangle$, where each of the $n$ component functions is integrable over $[a,b]$. I think the following inequality   $$\left|\int _a^b f(t) \, dt\right|\leq\int_a^b\left|f(t)\right| \, dt$$  still hold but I don't know how to prove it. Any idea?  Thanks


Travel to Switzerland with a multiple-entry Schengen visa

My husband has a Schengen visa from the French consulate issued in 2012, multiple entry, valid till 2017. We visited France in 2012 for 12 days, we visited Italy in 2013 for 11 days (no issues), now we want to visit Switzerland for 12 days using the same visa (still valid).  Will there be any problems ?


In Rogue Legacy how does your character being gay effect you

All I could find is that the genders of statues are reversed if your character/child in Rogue Legacy is gay. Is this really all that happens or is there any kind of additional trade off (benefit/loss) of any kind?  I only found an answer in Wiki so I wanted to double check this.


When exactly does the Unsung Hero badge get awarded?

A while ago, I spotted the gold badge, , which carries the description, Zero score accepted answers: more than 10 and 25% of total.  The way I interpret that is that you need more than 10 zero score accepted answers, and at least 25% of your accepted answers need to be zero score.  I'm guessing my interpretation is incorrect, as looking at my own profile, I have:   35 accepted answers with scores 12 accepted answers without scores 47 total accepted answers 12 out of 47 is 25.53% zero score answers   So by my reckoning, I should have that badge.  My zero score accepted answer percentage was higher a week or so ago (I seem to recall it was around 27% or 28%), but has since decreased as I've had some answers accepted recently that had been up voted.  Can anyone explain this? I'm guessing I'm misinterpreting the badge description?


I'm preparing to publish my first paper. I have a question on my name to use on the paper. I'm commonly known as Steve (which I've been using for absolutely everything) but my passport name is my Chinese name (which almost no one knows about). My enrolment is under my passport name. Do I have to use my passport name as the author of my paper?


$f(x) = \dfrac x {(x-3)}$; $g(x)= \dfrac {-7}{(x+7)}$   I found The domain of $(f \circ g)$ is $(- \infty, -28/3) \cup (-28/3 , -7) \cup (-7, \infty)$ which is correct.   Can someone please tell me the domain of $(g \circ f)(x)$ ? Show work if possible please.   Thanks!


I want to draw a set in a set with M being the subset and N the other set. I want them to look like "clouds", not perfect circles. I only came up with drawing perfect circles using the \draw (circle) thing, anyone got an idea?  Best regards,  Dan


I know there are already questions for validating links. But I'm very bad with regex, and I don't know how to validate a user input (in html) is equivalent to these URL:  http://www.domain.com/?p=123456abcde   or  http://www.domain.com/doc/123456abcde   I guess it's like this  /^(http://)(www)((\.[A-Z0-9][A-Z0-9_-]*).com/?p=((\.[A-Z0-9][A-Z0-9_-]*)   I need the regex or the two URL. Thanks


How do you find the general expression of a derived sum?

We got an exercice about maximum and  minimum and there is a question about a sum. The goal is to find the general expression of the sum ( without the sigma ). And there is a kx^k form. We need to derive and I can understand why but I just can't find how you derive a sum.


All that is needed are angle brackets.  All that are needed is angle brackets.  For some reason the first sounds better to my ears. Any help on why (or how I am wrong) is appreciated.


Redirect www to non-www using Apache htaccess does not work

I have this in my .htaccess (modified from the default Drupal .htaccess):  RewriteCond %{HTTP_HOST} ^www\.website.com\.com$ [NC] RewriteRule ^(.*)$ http://website.com/$1 [L,R=301]   In theory this will redirect something like http://www.website.com/asdf to http://website.com/asdf. However, it doesn't redirect, it allows requests to go through like there was no redirect intended.  (I'm on OS X if it matters, but I've also tried it on a Network Solutions Linux server with the same result.)


Let $I$ be an ideal of ring $R$ . If $K$ is ideal in $R/I$. Show that $K=J/I$ for some ideal $J$ which $I\subset J$ .  I was thinking $J=a+(-I)$ which $a\in K$ but I stuck to prove that $J/I\subset K$


unconditional probability, fake coin tossing

I need some assistance in solving the following problem:  We are given a bag containing n unbiased coins. We are told that n − 1 of these coins are normal, that is, they have a head on one side and a tail in the other. The remaining one is fake and has heads on both sides. We are picking a coin from the bag uniformly at random.  We can devise the following method to determine if the coin is fake or not. We flip it k times, afer which we conclude that it is the fake one if all k flips have resulted in heads, else we conclude that it is normal. What is the probability that using this method we arrive at a wrong conclusion?   I declare the following events :   F : the coin we picked is the fake one N : the coin we picked is normal (simply F complement) Hi : outcome of the i'th toss is a head   I though of simply solving this problem by calculating P[N | H1, ... , Hk] but it turns out we need to solve this problem using unconditional probability, and this is where I am stuck.


I can't seem to understand the dual nature of matter completely.   If electrons have a wave nature, then if two electrons were to collide, wouldn't they undergo interference and form an electron wave of larger or smaller amplitude? Does that mean the electrons merge and turn into a "bigger" electron?  Then again, this would mean that the electrons would have a phase difference, so what determines the phase of matter?  Also, if we were to consider two photons colliding, would they also undergo interference and form a "bigger" photon?  Why don't normal everyday objects undergo interference? Just because the wavelength (according to the de Broglie equation) of something is small doesn't mean that it doesn't undergo interference (take for example gamma rays which have a very small wavelength but are the most powerful form of radiation).


Is there a substitute for aluminum foil?

Is there a replacement that can be used for aluminum foil in the oven?    I don't want to foil in my kitchen. Is there an alternative which can be used in the same way as aluminum foil, but has no risk of transferring aluminum to the food?   For example, what can I use to cover a meatloaf when baking it in the oven? Or in a slow cooker?


I need to get the number of seconds since the last reboot, using ksh.  What is the command or function to achieve this?


CLT approximation - how large should sample be so probability is equal to 0.95?

We have a measurement which has mean $\mu$ and variance $\sigma^2$ = 25. Let $\bar{X}$ be average of $\textit{n}$  such independent measurements.  How large should $\textit{n}$ be in so that $P(|\bar{X} - \mu| < 1) = 0.95$  This is what I got so far:  $P(\frac{\sqrt{n} * (-1)}{\sqrt{25}} < \frac{\bar{X} - \mu}{\sqrt{25}} < \frac{\sqrt{n} * (1)}{\sqrt{25}}) = 0.95$  Yielding  $\Phi(\frac{\sqrt{n}}{\sqrt{25}}) - \Phi(-\frac{\sqrt{n}}{\sqrt{25}}) = 0.95$  And this is when I get lost. How do I remove the $\Phi$ so to find $n$? I tried to find the z-value corresponding to 0.95, which is 1.65, but that did not help.  The correct result is $n=96$ (it is an exercise from Rice, third edition, problem 5/17).


What documentation is needed for a tourist to drive a US citizen's car?

A common  says that buying a car as a tourist in the US is difficult because of registration and the time it takes to do the paperwork. However I have a friend in NYC who can buy any car I want in his name. After my trip to the States is finished, he would sell it and wire me the money.  So the question is — what documentation (insurance, etc.) is needed for me to drive my friend's car in the US as a tourist?


Getting higher power output by using more resistors

Is there anyway I can connect resistors to allow them to take more power such as using 4 1/4 watt resistors to get a 1 watt resistors. Or do i just have to use 1 1 Watt resistor.


i upgraded 14.04 ubuntu to 16.04, after updating softwares in 16.04 my desktop screen flickers when i place mouse pointer in the launcher pad. how can i solve the issue?


Strange spots on the image when filming video

When I'm filming video with my Canon EF-S 10-18mm f/4.5-5.6 IS STM lens, strange dark spots appear in the video and they are only visible in video mode and they are visible ONLY when focusing process is finished. In the picture below you can see on the upper side clean image, because its still focusing and the bottom with all these spots.... Here is a sample video with the problem   Any ideas what is causing it and how to fix it ?


I executed    git add .   and now I want to revert that git add. How can I accomplish that?


What are the different meaning int the following sentences?    They have been dating for a year now.  They will have been dating for a year now.


Can I use #14 wire on a 20A circuit for a compressor outlet?

Installing a single receptacle, non gfi, on a 20 amp breaker to be used only for a specific piece of equipment (compressor). Compressor specs say, “power consumption will average between 9-11 amps of power and spike near 16 amps”. Can I get away with 14 gage wire? This is for a home food Freeze dryer


My question is about updating .deb packages in 20.04. I understand that the Ubuntu software center will not support .deb packages in 20.04.  I like to use Google Chrome, which is only available as a .deb package (or .rpm). What is the best way to install Chrome on 20.04? Should I use dpkg?  And if I use dpkg, how do I make sure Chrome remains up to date? In 18.04 Chrome gets updated via the update manager (I think also via the apt package manager). Will this still happen if I install Chrome on 20.04 via dpkg? Is there any way to have it automatically updated via the update manager or via apt?  Thanks for taking the time to view my question.  Regards, Thomas


File Open/Save Dialog causing applications to crash

Seemingly ever since the Windows 10 Creators Update installed itself on my computer, I've been having issues when using the File Open/Save dialog. If I try and open a file, save a file, or upload a file to attach to an email, the application that I'm using will crash (whether it's Chrome, Word, Paint etc). Edge, however, works fine and weirdly, Firefox also works fine.  I have been doing some debugging, trying to figure out what it could be, but I'm running out of things to try.  I've tried the following:   Resetting folder views to default Enabling "Show all Folders" in Folder View Settings Starting computer in safe mode (where the dialog would work just fine)   I have also run some tests using MS Paint. I downloaded an application called DebugDiag 2, and had that watch the mspaint process to capture the exceptions thrown when the application would crash. These are the ID's of those exceptions:   0XC000001D 0XC000041D   Still using MS Paint as my test application, if I ran it as an adminstrator, I was able to use the File Open/Save dialog perfectly fine, but closing the application then reopening as a normal user would then end with the application crashing upon trying to open a file.  Another thing I've noticed is that when I first sign into Windows, I have about 30 seconds where I can open MS Paint, and be able to use the File Open/Save dialog just fine. After that time, if I close the dialog and then try to use it again, the application will crash.  I've read online that this issue is sometimes caused by the File Open/Save dialog trying to show a folder that no longer exists, or is on an unreachable network drive. So with that in mind, I have restarted my computer (getting that 30 seconds of grace when I first sign in) to be able to open MS Paint, and save a new file to my downloads folder, in the hopes that it would update the "last used folder". Unfortunately, this didn't solve the issue.  Is there anything else I can try?


Simple Mode - Is using checkpoints to truncate the transaction log a bad practice?

I have a database with simple recovery mode. For that database I have a job running every morning. This job imports data and executes plenty stored procedures that inserts data, updates records, delete records, makes calculations... The job takes approximately 30 minutes and makes the transaction log be 10GB big. To avoid growth of the log file during the job I set the log size to 11GB. With that amount it is never autogrowing. Nevertheless it is blocking 11GB. I think it is useless knowing that I will never need to make a recovery (every job empties all the tables and populate them from scratch every morning).   I just read that putting checkpoints truncates the log. So my idea is to put checkpoints at several location in my stored procedures in order to be able to minimize the size of the log (from 11GB to lot less: 3GB for instance).  Question: is it dangerous to do that take into consideration once again that I will never have to make recoveries?


Wifi won't connect after suspend Ubuntu 16.04

I have an Thinkpad R61e that I've installed Ubuntu 16.04 LTS on. When the system suspends WiFi will not connect until I reboot. I've tried restarting network manager, but this does not correct the problem.  Any suggestions or help appreciated.


A friend of mine has noticed something I say differently to move people. Most would contract the sentence "we have not done" into "we haven't done". I turn it into "we've not done". This seems to be correct as well, but people have told me its odd or wrong. I'm I incorrect or just different? If it is of any importance I am from the south-east of England. Any information on this will be kindly received.  Thanks in advance


i'm 100% positive this has been asked before. but ive wasted most of my day off and i can't find any straight answers for my problem... I need Unix/Linux on my computer to run some astronomy programs. I have a 1TB HDD and a 150gig, my 1TB has windows and everything on it. i want to install ubuntu on the 150gig so all i have to do is boot from the separate hard drive and everything i do in ubuntu is on that 150 gig. keep everything separate. but every time i try to install it i get problems.  To list a few, I got an ISO i received no information on how to use. i used the application saying i needed to insert a CD. i don't have a cd. i clicked the "i cannot boot from CD" option and spend 30 minutes waiting for it to do something. and installed a trial version. or something. i went to install the full version and it wasn't reading the 150 gig. HD.  I got a bunch of restarts with "cannot find an OS" and had to manually reboot from the 1TB, my computer not reading my USB to install from usb. and a bunch of other stuff  TL;DR I wan't to know how to make an installation USB drive that will let me INSTALL Ubuntu on a second hard-drive i have. Not Run off the USB in a virtual window. which is another problem that i had when trying to get an installation usb


LU factorization of a 2X2 singular matrix

My book is asking me to show that every matrix of the form $A=\begin{pmatrix}0&a\\0&b\end{pmatrix}$ has a $LU$-factorization and to show that even if $L$ is a unit lower triangular matrix that the $LU$ factorization is not unique.  Doesn't this contradict the theorem for $LU$ factorization which says for a matrix $A$: If the leading principal minors of $A$ are all nonsingular, then $A$ has an $LU$ decomposition.  Clearly, the leading principal minors of $A$ are singular.  What does this mean? What is the $LU$ factorization?


Does anyone knows how can I use square brackets instead of parenthesis when numbering my equations?  I used this command:  \begin{equation} y = 2x \end{equation}     The number appears on the right hand side like (1) I want to make it [1].  Does anyone have any ideas?


Why is every prime number ($5$ and higher) divisible by $24$ (into a whole integer) when you square it and subtract $1$?

I asked this question on puzzling.se and someone suggested I post it here:  I discovered this by accident, when trying to create a formula that generates prime numbers (an impossible task, I know).  But, I find it very interesting that you take any prime number 5 and greater, then you square it and subtract 1, dividing it by 24 always results in a whole integer.  For example:  5 x 5 = 25 - 1 = 24 / 24 = 1 7 x 7 = 49 - 1 = 48 / 24 = 2 11 x 11 = 121 - 1 = 120 / 24 = 50   The result is always a whole number, regardless of how high the prime number is.  Can someone explain why this is so, mathematically? This does not seem possible (to me). And if this is really true, why can I find nothing written about it?  I have never heard of this theorem before, and nothing is mentioned on Wikipedia or other sources. But perhaps this could be a helpful in reducing $33\%$ of the possibilities when trying to find or prove large prime numbers, computationally.  UPDATE: lab made the observation that all resulting numbers are apparently also divisible by $24$ ..  interesting  UPDATE: following lab's observation , I tried $24 \times 24 = 576 + 1 = 577$  ( a prime number)  .. interesting  and..  $576 \times 576 + 1 = 331,777$ which is also a prime  Further extrapolating in the gap of numbers between $2$ and $50$:  primes:   24 x 3 = 72 + 1 = 73  72 - 1 = 71  72 + 7 = 79 24 x 4 = 96 + 1 = 97   96 + 5 = 101  96 + 7 = 103    24 x 5 = 120 - 7 = 113  120 + 7 = 121 24 x 6 = 144 - 7 = 137  144 + 7 = 151 24 x 7 = 168 - 1 = 167  168 + 5 = 173 24 x 8 = 192 - 1 = 191  192 + 5 = 197 24 x 9 = 216 + 7 = 223   Not a perfect formula for finding primes, but seems to be effective :-)


Mirroring 2 out of 3 HDMI displays (2 monitors and 1 TV)

I have a Nvidia Geforce GTX 770 and use 2 BENQ 1080p monitors. I would like to mirror my other screen (Television 1080p) with one of my BENQ screens.  I have read something about saving the config file and put some code into it. First I would like to know something about the config saving and if it's safe for my GPU.  Also, how do I save the config because I have already got the mirroring done but it doesn't save. I had read in the Terms that it's normal but possible??? Please could someone explain that to me?


spacing between Japanese words (xelatex)

I'm working with Xelatex 3.14159265-2.6-0.99991 (TeX Live 2014/Arch Linux), compiling my .tex file and getting a simple .pdf file.  I'm stuck on the following problem, occuring in a simple Japanese sentence. I want something like :     ABC せんつぶ まいたら ひとつぶに なあれ ひとつぶ まいたら   But all I get is (without any space between the Japanese words) :     ABC せんつぶまいたらひとつぶになあれひとつぶまいたら   I get the spaces only by using the \; "trick" but I would like to avoid it :  ABC せんつ\;ぶまいたら\;ひとつぶに\;なあれ\;ひとつぶ\;まいたら   I'm an absolute newbie and don't know how to handle this problem. Any help would be appreciated !    My .tex file :  \documentclass{article} \usepackage{xeCJK} \setCJKmainfont{Sazanami Mincho} \setmainfont{Sazanami Mincho} \usepackage[margin=4cm]{geometry} \usepackage{amsmath}  \begin{document} ABC せんつぶ まいたら ひとつぶに なあれ ひとつぶ まいたら \end{document}


Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?

This is a  about Fighting Spam.   Also related:                    There are so many techniques and so much to know about fighting SPAM. What widely used techniques and technologies are available to Administrator, Domain Owners, and End Users to help keep the junk out of our inboxes?  We're looking for an answer that covers different tech from various angles. The accepted answer should include a variety of technologies (eg SPF/SenderID, DomainKeys/DKIM, Graylisting, DNS RBLs, Reputation Services, Filtering Software [SpamAssassin, etc]); best practices (eg mail on Port 25 should never be allowed to relay, Port 587 should be used; etc), terminology (eg, Open Relay, Backscatter, MSA/MTA/MUA, Spam/Ham), and possibly other techniques.


How to get the entire list of operators?

I want to create a list with everything the spacebar operator search can produce. Is that possible?


Are there advantages of soaking rice overnight as opposed to only for 30 minutes?

All these years I've just washed rice, put it into a pressure cooker (a regular pressure cooker; not a rice cooker), added the right amount of water and cooked it until the first whistle. Both for brown rice and white rice.    But when looking up this page on , the author does two things differently. 1. She pre-soaks the rice for 30 minutes. 2. She brings the water to a boil before adding the rice to it.    On searching for more info,  and  recommend soaking rice overnight! This completely perplexed me.   Assuming that I want to cook my rice with soaking, how do I choose between soaking for 30 minutes and overnight? Is soaking overnight a safety concern? Is it better to soak it overnight in the fridge? Wont an overnight soaking make it absorb a lot of water and make it less suitable for cooking in a pressure cooker?


Color matching but print other lines too

I have an alias: alias grep='grep --color=auto'. I wish to have some way to print not only matching row but all of them and just color matching patterns. I doubt is there an option to do that in the grep itself. Any other tool ? Or idea how to achieve this ?


Latex Table giving me an error: Missing $ inserted

\begin{table}     \begin{tabular}{|c|c|c|c|c|}     \hline     \multicolumn{5}{|c|}{\textbf{Table 1:}Unfiltered Water}\\     Concentration of analyte in sample   & Avg & Std Dev &  RSD & 90\% CI \\      \hline     Total hardness (ppm $CaCo_3$ equiv)  & 97  &    2   &  2\%  & \pm 5   \\     Calcium hardness (ppm $Ca^{2+}$)     & 57  &    3   &  5\%  &  \pm 5   \\     Magnesium hardness( ppm $Mg^{2+}$)   & 40  &    3   & 7.5\% &  \pm 5 \\     \hline     \end{tabular}   This table is giving me an error. That says   ! Missing $ inserted. <inserted text> $ l.41 ...Co_3 equiv\) & 97 & 2 & 2\% & \pm 5 \I've inserted a begin-math/end-math symbol since I think   you left one out. Proceed, with fingers crossed.  What is the cause of this error?  I can't seem to find any thing that is mismatched.


I have a question regarding the sum of this series: $$\frac{3}{1!+2!+3!} + \frac{4}{2!+3!+4!} + \cdots + \frac{2008}{2006!+2007!+2008!}$$ My approach: I found that this sum is equal to: $$\sum_{n=3}^{2008}\frac{n}{(n-2)!+(n-1)!+(n)!}$$  I reduced it to : $$\sum_{n=3}^{2008}\frac{1}{n(n-2)!}$$  Please suggest how to proceed further.


How to limit the results to 1 row in Oracle SQL

I've this query which runs successfuly  SELECT customerNumber FROM ORDERS  GROUP BY customerNumber  ORDER BY count(orderNumber) DESC   But when I try to limit the number of rows returned to 1, I get the following error  ORA-00933: SQL command not properly ended    Here's what I've tried :  SELECT customerNumber FROM ORDERS  GROUP BY customerNumber  ORDER BY count(orderNumber) DESC fetch first 1 row only;   and   SELECT customerNumber FROM ORDERS  GROUP BY customerNumber  ORDER BY count(orderNumber) DESC WHERE ROWNUM=1;


Is it possible to have a code block that isn't highlighted?

There are some languages that get highlighted incorrectly. Is it possible to specify a code block that does not have any highlighting when it gets displayed?  Here is an small example of CSS that is getting highlighted as if it was C/C++.  #div.a {   background-color: #000000; }  .static { }