Dubai transit - is there a 48 hour visa on arrival for Indian citizens?

On my return journey along with family from the UK, I have a layover of more than 12 hours at Dubai airport. I want to use this time to visit the city and sightsee. I am booked on Emirates right through the journey on all 4 legs of the trip and there is no change of terminal. We are all Indian citizens so I am aware I need a transit visa to enter the city of Dubai.  I spoke to customer service at Emirates and the person mentioned that I can get a 48 hour visa on arrival at Dubai airport for this purpose. Can somebody confirm the same? Have any Indian travellers through Dubai availed this service recently and the info is valid?    I was under the impression that as an Indian citizen I am not eligible for a visa on arrival at Dubai and I needed to arrange for it before the journey. I will have a valid UK visa stamped in my passport upon arrival at Dubai.  Another question - if I apply for the visa through VFS, do I need to supply proof of accommodation in Dubai? Since I plan to spend about 8 hours in the city, I don't have any hotel booking.  Thanks for your responses and inputs.


Strategies for putting away money for a child's future (college, etc.)?

So my wife and I will be having our first child at the end of the year, and I'm trying to devise a strategy for things like putting money away for the little person now, while I have the time and sleep in me to think about such things.  What are some good strategies to use to save money to give to a kid? College is obviously a big thing, but not necessarily the only thing I want to save for. My goal would be to have a respectable college fund to pay for a state college in 2029 and some money for general purposes. (Hopefully a car, trip or downpayment on a home and not beer)  Any ideas? I'm not opposed to 529 plans, but I don't necessarily want to tie all money up in one either. I'm also not concerned about colleges looking at assets in the child's name for financial aid purposes. (We're talking about 2029 or 2030 anyway, so it's unlikely that advice about that today would be valid that far out)


Showing that $p$ is a Fermat prime if and only if every quadratic non-residue mod $p$ is also a primitive root mod $p$

I want to show that $p$ is a Fermat prime $\iff$ every quadratic non-residue of $p$ is also a primitive root mod $p$ These are some facts that I know: $F_n = 2^{2^n} + 1$ Every prime divisor $p$ of $F_n$ is of the form $2^{k + 1}k + 1$ $\mathrm{ord}_{F_n}(2) = \mathrm{ord}_{p}(2) = 2^{n + 1}$ This is what I wrote for the ($\Rightarrow$) direction and I want to make sure it is correct: $p = F_n = 2^{2^n} + 1$ is prime, $\phi(p) = p - 1 = 2^{2^n}$ let $a$ be a quadratic non-reside mod $p$ so $x^2 \equiv_p a$ has no solutions. Suppose $ord_p(a) = h$. Since $h \ | \phi(p) = 2^{2^n}$ then $h = 2^k$ for some $k \leq 2^{n}$ Then $(x^2)^h \equiv_p x^{2h} \equiv_p a^h \equiv_p 1$ which is the same as $x^{2^{k + 1}} \equiv_p 1$ has no solutions therefore $2^{k + 1}\nmid 2^{2^n}$ We also know $2^k \mid 2^{2^n}$ so from these two we can conclude that $2^k = 2^{2^n}$ so the order of $a$ is $\phi(p)$ hence it is a primitive root mod $p$. I don't know what to do for the other direction. Hints would be appreciated.


When conserving angular momentum, about which point(s) should it be calculated?

In my physics problem I have a ball fired at a non fixed bar, which is moving at some velocity, causing them both to stick together and the bar-ball pair to rotate about the new center of mass. About which point(s) should I write my conservation of momentum equation? If I write it about the new com for both before and after, is it important that the bar is originally moving?


is this allowed in java:  for(int i=0;i<5;i++){   final int myFinalVariable = i; }   The keyword of my question is final. Is it allowed to do a final variable that changes with every run of the loop? I was wondering this because final says that you can't change the value of the variable (calling only myFinalVariable = i), but i'm redefining the whole variable with final int.   Are they two completely different variables just with the same name - with the variable from the previous run of the loop already heading down the road to the garbage collector?


Combinatorial Identity $(n-r) \binom{n+r-1}{r} \binom{n}{r} = n \binom{n+r-1}{2r} \binom{2r}{r}$

Show that $(n-r) \binom{n+r-1}{r} \binom{n}{r} = n \binom{n+r-1}{2r} \binom{2r}{r}$.   In the LHS $\binom{n+r-1}{r}$ counts the number of ways of selecting $r$ objects from a set of size $n$ where order is not significant and repetitions are allowed. So you have $n$ people you form $r$ teams and select $r$ captains and select $(n-r)$ players.  The RHS divides up a team into 2 sets?


How do I migrate my Keychain's "Local Items" to a new Mac?

After preforming a Mavericks-Mavericks migration using Migration Assistant, I have a "Local Items" Keychain on my new machine in which many (perhaps most) items are out of date (using old passwords), and some are missing altogether. While I have access to a copy of the entire contents of the ~/Library/Keychains/ directory from my old machine, which presumably contains all the information I'm missing, I see no way of importing that information into my new machine.  How can I import the "Local Items" from my old Keychain into the Keychain on my new machine?


I am reading Naive Set Theorey by Halmos, and am struggling to understand the Axiom of specification.  I understand: Axiom of specification. To every set A and to every condition S( x) there corresponds a set B whose elements are exactly those elements x of A for which S( x) holds.  But I don’t understand what Halmos is talking about here: It follows that, whatever the set A may be, if B = {x ∈ A: x ∉′ x}, then, for all y, Can it be that B ∈ A? We proceed to prove that the answer is no. Indeed, if B ∈ A, then either B ∈ B also (unlikely, but not obviously impossible), or else B ∈′ B. If B ∈ B, then, by (), the assumption B ∈ A yields B ∈′ B–a contradiction. If B ∈′ B, then, by () again, the assumption B ∈ A yields B ∈ B–a contradiction again. This completes the proof that B ∈ A is impossible, so that we must have B ∈′ A. The most interesting part of this conclusion is that there exists something (namely B) that does not belong to A. The set A in this argument was quite arbitrary. We have proved, in other words, that nothing contains everything,  How can B ever belong to B?  Thanks in advance


How to escape curly braces in Json string in C# string formatter

I have problem in formatting json string in c#  I have following two lines  string formater = @"{'attachments':[{'title':'New item added','title_link':{0},'text':{1},'image_url':{2},'color':'#764FA5'}]}"; string myJson = String.Format(formater, product.Url, "text", product.ImageUrl);   I'm getting this Exception  System.FormatException: Input string was not in a correct format.   I think because of curly braces inside formatting string, how can i escape?


Game flicking chequers knocking opponents off

My brother and I play this game using 8 white checkers and 8 black checkers on opposite sides of the board. We take turns flicking the checkers across the board to knock the opponent's checkers off the board. Once all the opponents checkers are gone, you win that round. We called this game "Chinese Checkers", but apparently . So, what is this game supposed to be called?


I installed SSL using  but after I finished, I was unable to start up WampServer. I made sure to follow everything correctly in that guide (replacing the paths given in the guide with the ones on my computer).   I looked through my error logs and found nothing from the times I was trying to start the server. When I try to start it using command line with httpd -d, I get the error   AH00526: Syntax error on line 51 of ......./apache2.4.2/conf/extra/httpd_ssl.conf:  Invalid command 'SSSLCipherSuite', perhaps misspelled or defined by a module not included in the server configuration   although I have mod_ssl.so in my modules file.  Any ideas?


In how many ways can $5$ balls of different colours be placed in $3$ boxes of different sizes if no box remains empty?

5 balls of different colours are to be placed in 3 boxes of different sizes. Each box can hold all 5 balls. The number of ways in which we can place the balls in the boxes so that no box remains empty.  My attempt:-  First choose 3 balls to be placed in 3 boxes so that none of them remain empty in ${{5}\choose{3}}\cdot3! = 60$ ways.  Now remaining 2 balls can go into any of the 3 boxes in $3\cdot3 = 9$ ways.  Total number of ways $= 60\cdot9 = 540$.  Where am I going wrong ?


How do I determine what file occupies a given sector?

I have a hard drive with 3 bad sectors. I know the sector numbers and the computer can still boot into Windows. I want to run sector repair from an HDD diagnostics tool from the manufacturer, but before I do that, I'd like to know what files are affected. Is there a way to figure out what file or files are occupying those sectors?


How can I see system logs while booting up ubuntu?

When I am waiting for Ubuntu to boot, I can see the splash screen but it often freezes or is sometimes really show. I would like to troubleshoot my system.  How can I switch the screen to see what is happening while I wait for Ubuntu to boot?


How to disable the built in mouse pad in a laptop?

My touch pad is not functioning well , it make wrong moves even if i connect a usb mouse   is there a tip to disable it and just use the usb mouse ?


What is the optimal length for user password salt?

Any  at all will obviously help when salting and hashing a user's password.  Are there any best practices for how long the salt should be?  I'll be storing the salt in my user table, so I would like the best tradeoff between storage size and security.  Is a random 10 character salt enough? Or do I need something longer?


I am using panasonic 25mm 1.7 lens in olympus omd-em10 ii body. Neither of them have a uv coating. Will it hurt lens/processor health if I use it without filter?


How to study/prepare for the Salesforce Developer Certification

I am fairly new to Force.com development (less than a year). I did not learn it from the ground up. So I think it will be good to study for the developer exam to strengthen my basics and improve my overall knowledge of Force.com + it will be great to have this certification.  Now it's surprising that there is not a lot of great information on the web about how to go about obtaining this certification. Most other major certifications have dedicated study guide books available but there are few for Force.com and I don't think any of them are official.   The official page has little information. The Study guide gives a broad description of the topics in the test.   I see a lot of the esteemed members are here certified developers. I think if you guys could give us a little information, hints/tips and some advice on how to prepare for this exam, it will really be of great help. Also is DEV401 required/helpful?  Also if we could get recommendations for great resources(books, online training etc) and practice tests it will be awesome.


I used to have this problem sometimes in Vista, but now I'm using Windows 7 (it was a clean install, reformatted hard drive) I'm disappointed that it's happening again.  Basically what happens is sometimes when I right click on something and click an entry in the context menu, the highlight from entry remains on the screen, in front of everything else.  I can get rid of it by changing my theme to Aero Basic and back again, but it's not a nice solution as it takes too long and often once I get rid of it, it comes back.    Here you can see an example of what's happening - the highlight is there from Chrome's context menu.  Does anyone know how to fix this?


'Is' or 'are' – which is correct in this example?

Which is correct?:  "One in seven people worldwide is living on $x per day."  "One in seven people worldwide are living on $x per day."


How to remove Windows after installing Ubuntu?

I installed Ubuntu 13.04 on my Vista 64 bit machine and I thought it was going to uninstall Vista but it didn't, now I have both systems.  How do I get rid of Vista?


Why do we say "of mine/of his" instead of "of me/of him"?

He's a friend of mine.   That's a car of his.   Why do we use the possessive when the meaning would be the same while not using it (e.g. a friend of me and a car of him)?  I thought maybe it is short for That's a car of his [cars], but I have no way of making sure; it sounds a little odd that way to me.


Wireless WiFi antenna not plugged, despite it being installed

So, I got a WiFi USB antenna, and managed to install the drivers both with apt-get and with a Git-hub, I think the problem is not there.  sudo apt-get install rtl8812au-dkms   I verified that it was installed using the following:  sudo dkms status lsmod | grep 8812   wich gave me  rtl8812au, 4.3.8.12175.20140902+dfsg, 5.3.0-28-generic, x86_64: installed rtl8812au, 5.6.4.2, 5.3.0-28-generic, x86_64: built    and    8812au               1290240  0 cfg80211              704512  4 iwlmvm,8812au,iwlwifi,mac80211    That makes me think that the drivers are actually installed, but when I plug the antenna nothing happens. I know similar questions have been asked, but I've found no solution in those questions, sorry if the question is poorly worded or tagged or anything, first time asking.    EDIT1 This is what happens when I run the lsusb command without the device plugged in:  $ lsusb Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller Bus 001 Device 002: ID 8087:0a2a Intel Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   And now, with the device plugged in:  $ lsusb Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 006: ID 0bda:b812 Realtek Semiconductor Corp.  Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller Bus 001 Device 002: ID 8087:0a2a Intel Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   EDIT2 SOLVED Thank you so much guys, it was the wrong driver. I needed the rtl88x2BU drivers. For Kernel 5.3, I got the working drivers in this GitHub


If $a_n \ge 0 $ for all n, prove that $\sum_{n=1}^\infty a_n$ converges if and only if $\sum_{n=1}^\infty {a_n\over 1+a_n}$ converges.   Here is my attempt!  => Suppose that $\epsilon \ge 0$ is given and $a_n$ converges, then  for all $N\le n \le m$$$\sum_{k=n+1}^m a_k \lt \epsilon.$$ let $b_n={a_n\over 1+a_n}$ and Notice that $b_n \lt a_n$ and   Then, applying the comparison test  $$|\sum_{k=n+1}^m b_k| \le \sum_{k=n+1}^m |b_k |\le\sum_{k=n+1}^m a_k\lt\epsilon$$Hence,${a_n\over 1+a_n}$ converges.  let me know if it is worng and I don't know how to start for the other direction. Any help is appreciated!


Correct Usage of Plural Possessive Word "user"?

Which of the following is the correct usage of the plural possessive word "user"?     We would like to store a cookie in every user's browser.   or     We would like to store a cookie in every users' browser.


I have ubuntu 14.04 LTS installed on my Dell PC but last time Skype didnt work under Ubuntu 14.04  LTS. Do I have to update Ubuntu to 14.04.1 or update Skype?


How can I reply comments posted by 2 users with identical name?

How can I reply to a specific user If 2 users with indentical names post comments on my question?   ex : Look at the following comments posted by 2 diffrent users :  What have you tried so far - Mark B  Have you checked your error log? - mark B   In this situation How can I reply to the first comment with @username?


Is the name Millennium Falcon a reference to FALCON codes?

Has Lucas ever given any reason to think the name "Millennium Falcon" is an indirect reference to US military aviation FALCON codes?  From  we see that FALCON 1000 means "Cool it, the Chaplain's here" or, , "Cool it the Padre is here".  Note that religion is a common StarWars subtext, and the Millennium Falcon is often trying to escape the "Father".  Also, I could have sworn I remember Han saying "Cool it" at some point but I can't find any proof of that.  Somewhat related to  but that seems to be asking for a in-universe answer, whereas I want a behind-the-scenes answer.


Why is  due to external charge i.e a charge outside a closed surface equal to 0?  P.S:Moreover I found this statement confusing:-  Electric field appearing in the Gauss' law is the resultant electric field due to all the charges present inside as well as outside but the contribution of outside charges in producing flux is zero. Can someone help me understand it.


I have some routable data for testing my pgRouting functions, and everything is fine. Now I have to download some more countries from OSM. I downloaded Germany shape files, but OSM maps are not routable. OK, next step, I found osm2pgrouting Import Tool but it works only on Linux, I need Windows version. Is there any possibility to make OSM map routable on Windows?


How to change colour of all elements of a group, at once, in Illustrator

I have a group of objects of the same colour, consisting of compound paths, regular paths and groups of these. How to change the colour of all objects at once? When I tried to use colour picker or change it through color palette the colour remained the same but the graphics was rendered with a very tiny outline of the new colour, which I guess is not printable. Usually I had to change the colour of all objects individually.  Edit: I'm sorry if I was not too precise. I mean to apply new colour / swatch to all member objects of the group at once, not to change properties of a commonly shared swatch.    Edit 2: I received very useful answers, however my goal was to pick a colour from another object, serving as a source. When I tried to select all objects, for example with ctrl-a, and then use a eyedropper to pick up a desired colour, it didn't work for some objects in some groups. Please have a look at my answer where several methods are listed.


How to temporarily set a game object active?

I'm trying to an use IEnumerator method called Wait() to temporarily enable and then wait, and disable a gameobject within a method. Basically I'm trying to create a muzzle flash within a shoot method, but whenever I add the muzzle.SetActive(false) to the method, it never activates in the first place. This code should work right? void Shoot() {     muzzle.SetActive(true);     RaycastHit hit;     if (Physics.Raycast(fpsCam.transform.position, fpsCam.transform.forward, out hit, range))     {         Debug.Log(hit.transform.name);          Target target = hit.transform.GetComponent<Target>();         if (target != null)         {             target.TakeDamage(damage);         }     }     Wait((float).1);     muzzle.SetActive(false); }


I'm trying to add a 72 pt. space before the section heading. I do not only want the 72 pt. between paragraphs but basically every section should start at a new page with a 72 pt. spacing before it.   Preambel:   \documentclass[a4paper,12pt]{article} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage{blindtext} \usepackage{indentfirst} \usepackage[top=3cm, bottom=3cm, left=3cm, right=2cm]{geometry} \usepackage{titlesec} \titlespacing*{\section}{0pt}{72pt}{18pt}  \titleformat{\section}[block]{\normalfont\fontsize{16}{19}\bfseries}{\thesection.}{1em}{}    \titlespacing{\subsection} {0pt}{36pt}{18pt} % first paragraph should have 18 pt spacing before it \titleformat{\subsection}[block]{\normalfont\fontsize{14}{19}\bfseries}{\thesubsection.}{1em}{} \titlespacing{\subsubsection} {0pt}{18pt}{18pt} \titleformat{\subsubsection}[block]{\normalfont\fontsize{12}{19}\bfseries}     {\thesubsubsection.}{1em}{}   For example  \begin{document} \section{Section 1} \blindtext \subsection{Subsection 1} \blindtext \subsubsection{Subsubsection 1} \blindtext \section{Section 2} \blindtext \blindtext \end{document}   Result:   How the 72 pt. before spacing approx. should look like on every page where a new section starts:


Prove $\int_0^{\infty} \left(\sqrt{1+x^{4}}-x^{2}\right)\ dx=\frac{\Gamma^{2}\left(\frac{1}{4}\right)}{6\sqrt{\pi}}$

I have in trouble for evaluating following integral  $$\int_0^{\infty}  \left(\sqrt{1+x^{4}}-x^{2}\right)\ dx=\frac{\Gamma^{2}\left(\frac{1}{4}\right)}{6\sqrt{\pi}}$$  It seems really easy, but I don't know how to handle it at all. (The results are well known, here I tried to evaluate it but I failed)  I tried to use the relation   $$\sqrt{1+x^{4}}-x^{2}=\frac{1}{\sqrt{1+x^{4}}+x^{2}}$$   but I couldn't find the desired results.


Listing the files on a device from the command line

On the left side of the Dolphin display, one of the categories shown is "Devices".  Just as one would expect, clicking on any of the listed devices shows the files available from that device, e.g., a camera or a memory stick. if the device isn't read-only, you can even use the Dolphin display to add files to the device.  But how can one get that same list of files (for any listed device) from the command line, using either ls or something similar to it?  I would expect the method to be the same no matter what the nature of the device. And if the device is writable, how would you write to it from the command line?


How to customize .bashrc to configure command prompt?

Is there an easy way to change my Bash prompt to modify the colors and what text is displayed? I've heard that this is done in .bashrc, but I haven't found any nice, easy ways of modifying it. How are colors expressed in Bash?


How to determine the type of encoding of a particular string?

I tried looking at various SO answers but found nothing constructive enough. What I need to know is what kind of an encoding format is this \x86\x9cG<!\xd9F@\xb4\n\xd6\xd4(\x9cb\xfe.   Do I use any online tool? Do I write a code in python? Any help would be really good.  I want to know what kind of an encoding format is the above string. That's all.


Rational Equivalence Relation and Measure

Here is the problem and my attempted solution. Problem: Let $m^*(E) > 0$. Define the Rational Equivalence Relation on $E$ by $x \sim y$ if, any only if, $x - y \in \mathbb{Q}$. Show that the choice set $(c_E)$ for the Rational Equivalence Relation must be uncountably infinite. (my) Solution: Let $m^*(E) > 0$. Define the Rational Equivalence Relation on $E$ by $x \sim y$ if, any only if, $x - y \in \mathbb{Q}$. By way of contradiction, suppose that $c_E$ is countably infinite. Notice, one property of $c_E$ is the following: (i) For any $e \in E, \exists c \in c_E: e - c = q$, for $q \in \mathbb{Q}$. Therefore, by (i) if $c_E$ is countably infinite so is $E$. Since the Lebesgue Outer Measure of a countably infinite set is zero we obtain: $$m^*(E) = 0,$$ a contradiction. Hence, our assumption that $c_E$ is countably infinite is false. Therefore, $c_E$ must be uncountably infinite, as desired.


I have some doubts about the "natural" interpretation of $\bot$ in Natural Deduction and sequent calculus.  In Prawitz (1965) $\bot$ (falsehood or absurdity) is called a sentential constant [page 14]  Chiswell & Hodges (2007) list $\bot$ (absurdity) between the truth function symbols [page 32], and this is not very clear for me; then, in the formal definition of formula of a language [page 33] they say :     $\bot$ is a formula.   Negri & von Plato (2001) [page 2] list $\bot$ (falsity) between the prime formulas, specifying that :     Often $\bot$ is counted among the atomic formulas, but this will not work in proof theory. It is best viewed as a zero-place connective.   I think that the last comment is contra D.van Dalen, Logic and Structure (5th ed, 2013) [page 7] where $\bot$ is defined as a connective and :     The proposition symbols and $\bot$ stand for the indecomposable propositions, which we call atoms, or atomic propositions.   I'm wondering if all the above definitions are equivalent.  A (propositional) connective is an "operator" that maps one or more propositional variables into a formula; e.g.      $\land$ : <$P,Q$> $\quad \rightarrow \quad P \land Q$.   This means that the zero-place connective $\bot$ is a mapping      $\bot$ : $\emptyset \quad \rightarrow \quad \bot$.   If so, may we say that, being at the same time the mapping and the output of the mapping, it is both a connective and a formula ?


Assessing correlation with a variable in degrees

This is probably a fairly simple question but it occurred to me, when trying to go through some data, that I wasn't sure how.  Say you have some numeric variable vs. arc degrees-- like the price of real estate when looking in any direction. You want to see if there is a quadratic correlation between these two. In other words, the hypothesis is that land is most expensive in one direction, then gets less expensive -180 degrees away.   What's the standard way to treat or transform degrees, i.e. a repeating or circular variable?  There is a somewhat related question  but it also involves other things, and I don't see how the scale function in R applies here.


Compute $\int _0 ^{2\pi} (\sum_{n=1}^\infty \frac {\cos(nx)}{2^n})^2 dx$

Question:   Compute $$\int _0 ^{2\pi} \left(\sum_{n=1}^\infty \frac {\cos(nx)}{2^n}\right)^2 dx$$   Thoughts: Tried interchanging the integral and the sum, but then the integral turned out to be zero...


Can a Muggle inadvertently create a horcrux-like object?

I think that we have it well-established (regardless of whether or not one sees this as flawed logic) that Harry is not a Horcrux.  A Horcrux has to be made intentionally, and the recipient is cursed and classified as an "evil object," etc.  Neither of which is true for Harry - so, as stated by JKR herself, Harry is not a Horcrux as such.  But the fact remains that murder can, in fact, accidentally create something that shares a key property of the Horcrux: the soul splits, attaches itself to the nearest recipient, and lingers inside.  As it does in Harry's case.  So my question is: is this only true for wizards?  A Muggle cannot utilize a spell to create a Horcrux.  But, if a Horcrux-like object / being can be created accidentally through murder without intentional Horcrux-creating spells, can this also happen in the case of a Muggle committing murder?    Can a Muggle commit murder, have their soul split, and have the piece of the soul inadvertently attach itself to something nearby without any Horcrux-creating spell being cast?


Find $a$ by looking at the triangle containing squares.

Figure 1 shows an equilateral triangle with side length equal to  $1$. Two squares of side length  $a$  and  $2a$  placed side by side just fit inside the triangle as shown.


What’s the difference between all and all of?  When should one use of following all to make all of, and when should one drop the of and just use all all by itself?  For example, in this sentence:     How come I can understand spoken American English better than British English in all its variants?   Is an of required after the all, making it all of its variants instead?  Dunno why but my instincts tell me that I shouldn’t put the of in right there. But I am unaware of source of my instinct.


How can I set the root of one of my domains to mirror a certain page on another of my domains?

I want one of my domains (freelawofattractioncourse.com) to point to a page on another site of mine () without causing the URL to change in the visitor's address bar.   In other words, when a user browses to freelawofattractioncourse.com, freelawofattractioncourse.com should remain visible in the address bar, but the screen should show content from  (without the visitor even knowing that katievb.com exists).  My WordPress site is hosted on a Cloudways server.  I'm also using CloudFlare, and I have a "Forwarding" Page Rule set up so that freelawofattractioncourse.com gets bounced to  (but that's not quite what I want because it visibly changes the URL in the address bar of the browser).  Is there a setting in CloudFlare (or some other service) that will allow me to achieve my domain masking goal?  P.S. I don't want to use iframes.  Also, I think that editing htaccess in the following way would achieve my goal:  RewriteCond %{HTTP_HOST} freelawofattractioncourse.com$ [NC] RewriteRule ^(.*)$ http://katievb.com/freecourse [P]   But  says "mod_proxy must be enabled", and Cloudways (my server provider) won't allow that (and will not let me edit Apache virtual hosts).


The second law of Sir Isaac Newton or also known as the fundamental relation of dynamics : $$\vec{F}=m\vec{a}$$  Which can be derived using the definition of the force : $$\vec{F}=\frac{d\vec{p}}{dt}$$ But only if $m$ is treated as a constant. What if $m$ is not a constant? absolutely we're not having the same result. Then what we must apply $F=ma$ or $F=dp/dt$ ?


I am trying to send pdf through using mime mail module + mailsystem module + smtp authentication module   function send_mail(){ $to='xx@gmail.com'; $subject='xxxx'; $message='aaaaa'; $from='x123@gmail.com'; $my_mail_token = microtime(); $message = array( 'id' => $my_module . '_' . $my_mail_token, 'to' => $to, 'subject' => $subject, 'body' => array($message), 'headers' => array( 'From' => $from, 'Sender' => $from, 'Return-Path' => $from, 'Content-type' => 'text/html; charset=UTF-8',  ), );  $attached=$message['params']['attachments'][]  = array( 'filename' => $filename, 'path' =>DRUPAL_ROOT.'sites/default/files/pdf'.'/'.$uid.'/'.$filename, 'filecontent' => file_get_contents('sites/default/files/pdf'.'/'.$uid.'/'.$filename), 'mime' => 'application/pdf', 'Content-type' => 'application/octet-stream', 'encoding' => 'base64', 'disposition' => 'attachment', 'list' => TRUE ); $system = drupal_mail_system($my_module, $my_mail_token); //unlink('sites/default/files/pdf'.'/'.$uid.'/'.$filename); $message = $system->format($message); if ($system->mail($message)) { return TRUE; } else { return FALSE;     } }   This is the code its sending two files as mail attachments instead of one. Why its doing that i cant understand. Looking for help.


Duplicating layer and applying filter using PyQGIS?

Is there a way, using Python, to duplicate a layer in QGIS as many times as the single occurrences of a variable contained in a field and with a filter applied on the duplicated layer based on the variable itself?   An example: I have layer0 with a field0 that contains var1, var2, var3, etc. I would like the layer0 duplicated to layer1, layer2, layer3 etc. so that layer1 has a filter where field0 = var1, layer2 has a filter where field0 = var2, etc.  The idea is similar to the LayersByField plugin but instead of creating a new layer for each occurrence of a variable I wish to just duplicate the "master" layer (so to avoid unnecessary files on disk)


Group of order $p^2$ with Center of order $p$

I am sure this question was asked here before, maybe even multiple times. But I can't find it right now and it really bugs me:     Let $G$ be a group with $|G|=p^2$. Then $G$ is abelian.   For the proof we have 3 cases: $|Z(G)|\in\{1,p,p^2\}$, two of which I understand. Let $|Z(G)|=p$, then $G/Z(G)\cong\mathbb{Z}_p$, so $G/Z(G)$ is cyclical and therefore $G$ is abelian.   Question: This would mean that $Z(G)=G$, so there it's ultimately a contradiction although it proofs that $G$ is abelian. How do I interpret this proof?


I want to write some music symbols in TeX.       How should I write the Bémol, dièse symbols in TeX?


I would like to know why 'Who is there?' is correct and why we can't use 'Who are there?' even if we know there is more than one person.


Could anyone give me a suggestion to start solving this problem?  Proof that $(\mathbb{R}^{3},\times)$ is a Lie algebra that does not have Lie subalgebras of dimension 2.


There are two apps that can disable system apps (bloatware) from  and  devices. Those do not need root or any special permission. Can anyone explain how this works?


For proof-reading-purposes I would like Latex to begin every separate paragraph on a new page. Is it possible to redefine \par or issue a command to achieve this?  Example paragraphs:  sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris  nisi ut aliquip ex ea commodo consequat.   Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.  Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.```


Is it correct to say “Why your phone can't be reached?”

I tried to call a person many times but the line was engage and I could not make call. Now if I want to ask him the reason then is is correct way to say "Why your phone can't be reached" ?   Please also mention other expressions to say this thing.


Let $a$, $b$, and $c$ be integers with $\gcd(a, b, c) = 1$. Prove that there is some integer $x$ such that $\gcd(a + xb, c) = 1$.    I know I should use the Chinese remainder theorem, but I'm still a little stuck on this proof.


In Unity, how do I set up a delay before an action?

I want an object to rotate after a delay. I tried using StartCoroutine, yield and WaitForSeconds, but failed. How can I do it?


There is a compatibility problem between the  and the subcaption package. When I compile the following example (with PDFLaTex): \documentclass{cifa}  \usepackage{subcaption}  \begin{document} \begin{figure} \parbox{4cm}{\subcaption{This is a subcaption}\label{sub}}  \caption{nothing} \label{nothing} \end{figure}  See figure \ref{nothing}: there is \ref{sub} inside...  \end{document}  These warnings are displayed:  Package caption Warning: Unsupported document class (or package) detected, Package caption Warning: \caption will not be redefined since it's already  In addition the words "figure" and "subfigure" are displayed AFTER the captions. How to fix this issue?


How to get the number of times an audio file has been played

My aim is to get the total number of listens so I was thinking I could save a 'listen' count to the audio file's post meta using update_post_meta()  Is there a hook that fires each time an audio file is played?  Background: I'm using wp_audio_shortcode() to output the (mediaelement) player.   Refs:


How calculate hashCode of a Pojo by combining hashCodes of it's keys

Consider i have one POJO having String class members :  class POJO {   String name, address, emailId;   equals() {    }   hashCode() {     // How?       } }   How can i combine hashCodes of my strings to form a hashCode for POJO?


I am going to install texlive on windows 10. After running the "exe" file, the error comes out writing the line: Error: for better info, unpack, then run install tl.windows.bat. Anyway, the installation is in process, which I am trying after a failure to install which took more than 4 hours with unsuccess. So now I am trying again to install. But do not know why the above error came? I want to know does the above error affect the installation? Thanks.


group generators of $(\mathbb Z_{17}-\{0\},\times)$

How to find generators of $(\mathbb Z_{17}-\{0\},\times)$?  Is there a faster way to find generators than trying every element in the group?  I know that for additive group, if a number say m is relatively prime to n (in this case 17), then it's a generator of that group. Do we have something like this for multiplicative group?


Aligning equations - System of equations all numbered

I tried to write a system of equations with all equations numerated, but they are not aligned:  \begin{empheq}[left=\empheqlbrace]{align} R_a = R_d\\  \frac{dq(t)}{dt} = ir - r_d(t) \\  q(0)=0 \\ r_d(t) = TTR(t) R_d \end{empheq}   How can I solve this problem?  Thank you very much in advance.


I saw the same problem as in this () post  on Math.SE. I want to pay attention on it, because it linked post is written that this bug has been yet fixed.     Quote comes from  :      I noticed this anomaly after clicking the "load new answers" link :      As far as I can tell, this was caused by the following sequence of   events:         I loaded the question with one accepted answer and left the tab open for a while.   Meanwhile, a new answer was posted and the OP changed this to be the accepted answer.   I returned to the tab, noticed the "load new answers" banner, and clicked it.   The new answer got loaded, but now both were shown as accepted.         Of course, refreshing the page fixes the issue.


I want to create a site based on Wordpress that is only accessible from my own machine (localhost). In other words, I do not want my computer to be a server. I just want it to have all the files necessary for a website in /var/www/, so that I can later copy-paste those files an another machine which will be a server.  Therefore I installed the wordpress package and I am about to install a graphical interface to manage the files. What should I do? Do I need somthing called LAMP?  I have seen , but I wonder if someone could provide instructions that are more Ubuntu specific or easier to follow, especially if they are relevant to the Unity interface.


Is a convex and lower semicontinuous function defined on a closed and convex subset of $\mathbb{R}^n$ continuous?

Let $A\subset \mathbb{R}^n$ be a nonempty convex and closed set, and let $f:A\to\mathbb{R}$ be a lower semicontinuous and convex function.   Does this imply that $f$ is continuous on $A$?  I know that in the (relative) interior of $A$, $f$ is locally lipchitz so my question is about the points on the boundary.  Of course, I consider the continuity of $f$ with respect to $A$ and not the continuity of the extended function $\tilde{f}:\mathbb{R}^{n}\to\mathbb{R}\cup\left\{+\infty\right\}$ defined by $\tilde{f}(x):=f(x)$ for $x\in A$ and $\tilde f(x):=+\infty$ for $x\notin A$, which is obviously not upper semicontinuous on the boundary of $A$.  If the answer to my question is negative a counterexample would be welcome. Thanks!


I have a .ttf file in which I need to add some missing characters. Maybe some of you have faced and overcame this earlier? I would relay appreciate your time spared ;)


How to use timers in STM32 board and HAL library in order to measure speed of motor?

I need to measure the speed of a rotating motor fitted to an encoder disc with 20 slots. The LM393 based sensor is kept at the right place, so that encoder disc rotates in between the sensing part.  I think, I would need three timers provided by STM32 board: one to provide PWM(TIM4), second(TIM1) to measure the time of (1000msec~1sec) and third timer(TIM2) to measure the number of pulses received from encoder disc in 1 sec.   TIM1's counter period(Auto-reload register) is fixed to 1000 and frequency to 1000Hz. TIM2'S frequency is same as PWM frequency-10kHz. Sensor output is connected to PC15 and PWM to PD12.   The code below uses HAL library. I have doubt about how to use these two timers/counters inside the while loop, which HAL library functions to use here and how to use. Also should the code for PWM control and speed calculation be put in same loop.  int main(void) {         volatile GPIO_PinState level; // stores input state from PC15, sensor output is connected to PC15         uint16_t dutycycle=70;         int speed=0;                  //speed variable         int constant=(2*3*1)/20;      //roughly circumference/20 slots    /* Reset of all peripherals, Initializes the Flash interface and the Systick. */   HAL_Init();   /* Configure the system clock */   SystemClock_Config();   /* Initialize all configured peripherals */   MX_GPIO_Init();   MX_TIM1_Init();       //for measuring 1 second   MX_TIM4_Init();       //for PWM   MX_TIM2_Init();      //for counting output pulses from PC15 pin    HAL_TIM_PWM_Start(&htim4,TIM_CHANNEL_1);    //Start PWM signal   level=HAL_GPIO_ReadPin(GPIOC, GPIO_PIN_15); //HAL function is called to read pin status    while (1)   {               counter1=__HAL_TIM_GetCounter(&tim2);               speed=(counter1)*(constant);          //speed variable, counter 1 related to TIM2                htim4.Instance->CCR1=dutycycle;   //setting the duty cycle of PWM signal             HAL_Delay(1000);dutycycle+=10;    //1 sec delay and then increases dutycyle by 10%             if(dutycycle==90)dutycycle=50;    //resets to 50% duty cycle   }   Development board is STM32F407, CubeMX is the source code generator and IDE is Eclipse. OS is Linux(Ubuntu 15.04).  Kindly suggest.


Can different choices of regulator assign different values to the same divergent series?

Physicists often assign a finite value to a divergent series $\sum_{n=0}^\infty a_n$ via the following regularization scheme: they find a sequence of analytic functions $f_n(z)$ such that $f_n(0) = a_n$ and $g(z) := \sum_{n=0}^\infty f_n(z)$ converges for $z$ in some open set $U$ (which does not contain 0, or else $\sum_{n=0}^\infty a_n$ would converge), then analytically continue $g(z)$ to $z=0$ and assign $\sum_{n=0}^\infty a_n$ the value $g(0)$.  Does this prescription always yield a unique finite answer, or do there exist two different sets of regularization functions $f_n(z)$ and $h_n(z)$ that agree at $z=0$, such that applying the analytic continuation procedure above to $f_n(z)$ and to $h_n(z)$ yields two different, finite values?


Removing trailing whitespaces of a string in c++

I am trying to remove trailing whitespaces of a string in a concise/efficient way.   Let's say I have the string:  string input= "2 2 +                 "   I used this in an attempt to make it input = "2 2+"    std::string::iterator end_pos = std::remove(input.begin(), input.end(), ' ');   input.erase(end_pos, input.end());   cout << input << endl;   However, it removed all the whitespaces.   How would I implement it so it only removes trailing whitespaces?


Proving $M_n(I)\lhd M_n(R)$ and proofs about ideal rings.

I'm trying to do a few proofs about rings: $(1)$ I want to show that for a ring $R$ and the ring of matrices $M_n(R)$, if $I\lhd R\implies M_n(I)\lhd M_n(R)$ and that all ideals of $M_n(R)$ are of the form $M_n(I)$. $(2)$ Prove that if $R$ is a ring with division then $M_n(R)$ is a simple ring.  The relation $I\lhd R$ implies that with $r\in R$ and $x\in I$ we have $rx\in I, xr\in I$. But how can I prove the statement for matrices?, here's what I would do: Consider $\psi \in M_n(R)$, if is given any matrix $\phi\in M_n(I)$ it must be $\psi \phi \in M_n(I),\phi \psi \in M_n(I)$, if we denote the element $(i,j)$ of each matrix by $\phi_{ij}$ and $\psi_{ij}$, then $(\psi \phi)_{ij}=\sum_{k=1}^n \psi_{ik}\phi_{kj}$ and $(\phi \psi)_{ij}=\sum_{k=1}^n \phi_{ik}\psi_{kj}$.  Since $I\lhd R$ is $\psi_{ik}\phi_{kj}\in I$ and $\phi_{ik}\psi_{kj}\in I$, which means that $I\lhd R\implies M_n(I)\lhd M_n(R)$.  To show that every ideal of $M_n(R)$ are of the form $M_n(I)$ with $I$ ideal: Suppose $I$ is not an ideal of $R$, then exists $r\in R$ such that $rx\notin I$ or $xr\notin I$, then with taking a matrix $\phi\in M_n(I)$ such that $x$ is an entry of $\phi$ and a matrix $\psi$ such that $r$ is an entry of $\psi$ we get that the matrices $\phi$ and $\psi$ have an entry $xr$ or $rx$, in either case this is not an element of $I$ then the matrix is not in $M_n(I)$. This concludes my proof (is it?) for $(1)$.  For $(2)$ I'd like to proceed by absurdum . Let's say that $M_n(R)$ is not a simple ring, then it has at least one ideal. Denote by $\varphi$ this ideal in $I$, then for any matrix $\psi$ we have $\varphi\psi \in M_n(I)$ and $\psi \varphi \in M_n(I)$.  Now, can $R$ be a ring with division?.I'm not sure how to prove that it can't. I believe I could use this theorem: "If $I\lhd R$ and $1\in I$ then $I=R$. The case $I\neq R$ implies $1\neq R$ and since $\varphi \psi$ and $\psi \varphi$ are in $M_n(I)$ then there are at entries in the product matrix which belong to $I$ (using $I \lhd R$) but are not $1$ (1\notin I); then there are elements in $I$ (and therefore in $R$ by $I\subset R$) that are not invertible, follows that $R$ is not a ring with division. But if $I=R$?, here I can't see a why $R$ can't be a ring with division.


For integers $a$ and $b$, $ab=\text{lcm}(a,b)\cdot\text{hcf}(a,b)$

I was reading a text book and came across the following:  Important Results (This comes immediately after LCM:) If 2 [integers] $a$ and $b$ are given, and their $LCM$ and $HCF$ are $L$ and $H$ respectively, then $L \times H = a \times b$  Can some please help me understand why the above result is true? Thanks in advance.


Book (online?) where one common (and powerful) form of magic consists of making vows

I was reading Sew You Want to be a Hero, second book of the Threadbare series, and there's a scene where a character is commenting on how the Knight class (it's LitRPG where people are aware of their game stats) gain power by taking a vow and sticking with it, and it reminded me of another (non-LitRPG) work of fiction where there were several forms of magic, but the most common accepted one involves taking self-denying vows of poverty, chastity, etc to gain fighting prowess (and no, I'm not thinking of The Book of Exalted Deeds) with one particularly powerful warrior having given up eating and drinking for some decades (he wore a sort of armor that kept him from malnourishment, but does not alleviate the hunger and thirst). Initially, it's described only as being male warriors, but it later turns out that a set of religious sisters have a similar powerset owing to privation. A key factor in both forms is that you gain more power the longer you keep your vow, but the moment you break it, you're back to square one.  There were other forms of magic, one being some sort of "forbidden magic" that still works on sacrifice, but allows you to use the (possibly unwilling) sacrifice of others, and a lost art of enchanting objects (which is where the previously mentioned magic armor comes from).  I read this in the last decade, but I can't say where.


How would ubuntu 14.04 run on my hardware

So I'm very new to Ubuntu. I'm building a new computer to run on Ubuntu and I'm just wondering how Ubuntu 14.04 would run on the following hardware I have purchased:   4gb DDR3 ram AMD Phenom 2 Quad Core 2.5 GHz to 3.7 GHz (not sure) EVGA Nvidia GForce GT 610 WD Blue 1TB Desktop Hard Disk Drive - 7200 RPM SATA 6 Gb/s 64MB Cache


Possible to get SMS/text message notification when process ends or is killed?

There are scripts that will send an e-mail when a server process is finished.  However, I do not want to check my email every so often just to see whether a job has finished. Therefore I'd like to get an SMS message.  My question is similar to this one, just exchange SMS with all occurrences of "e-mail":   Can you think of any workaround / app / script / whatever that would enable an SMS to be sent when a job is finished (or prematurely ended?)


I want to know if is there a possibility/method/package, by which I can uniquely label all footnote positions in book.tex. And another file, footnote.tex, containing the footnotes and matching labels, which can be used for inserting footnotes?  Example:  blah blah blah\footnotemark{id1} blah blah\footnotemark{id2} in chap1.tex;  \footnotetext{id1}{blah blah},\footnotetext{id2}{blah blah blah} in chap1foot.tex. When chap1.tex is ran I need \footnotetext{id1}{blah blah} to appear with footnote counter starting from 1 in each page.


Best way to build a Plugin system with Java

How would you implement a Plugin-system for your Java application?  Is it possible to have an easy to use (for the developer) system which achieves the following:   Users put their plugins into a subdirectory of the app The Plugin can provide a configuration screen If you use a framework, is the license compatible with commercial developement?


How to get around a problem with \usetikzlibrary{babel}?

I am currently working on an update of tkz-euclide and new documentation but I just met the following problem. If I compile this code with pdflatex or lualatex and pgf 2.1 (The library babel does not exist with pgf 2.1) then the code compiles fine but with 3.0 pgf I must comment on the call \usetikzlibrary{babel} (pgf doc gives so I recommend to always load this library by saying \usetikzlibrary{babel}).  I'd like to know where the error occurred. Especially I would like to work around this problem.   With \usetikzlibrary{babel} I get the error Latex Error: ./untitled 2.tex:46 Undefined control sequence. l.1 \tkz@line@start  Bug in babel, bug in tikzlibrary{babel} bug in my code. I would like to keep  \usetikzlibrary{babel} but to avoid the error.  %!TEX TS-program = pdflatex \documentclass[a4paper]{article} \usepackage[french]{babel} \usepackage{tikz}  \usetikzlibrary{calc} %\usetikzlibrary{babel}  \makeatletter \pgfkeys{%     tkzdrawline/.cd,     start/.code         =  {\gdef\tkz@line@start{#1}},%     end/.code           =  {\gdef\tkz@line@end{#1}},%     start style/.code   =  {\tikzset{tkzstartstyle/.style={#1}}},%     end style/.code     =  {\tikzset{tkzendstyle/.style={#1}}},%    /tkzdrawline/.unknown/.code ={\let\searchname=\pgfkeyscurrentname\pgfkeysalso{%                          \searchname/.try=#1,/tikz/\searchname/.retry=#1}}}  %<--------------------------------------------------------------–> %                              Draw line %<--------------------------------------------------------------–> \pgfkeys{tkzdrawline/.cd, start/.code       =  {\def\tkz@line@start{#1}},% end/.code         =  {\def\tkz@line@end{#1}}, start style/.code =  {\tikzset{tkzstartstyle/.style={#1}}}, end style/.code   =  {\tikzset{tkzendstyle/.style={#1}}},   /tkzdrawline/.unknown/.code   = {\let\searchname=\pgfkeyscurrentname                                  \pgfkeysalso{\searchname/.try=#1,                                 /tikz/\searchname/.retry=#1}}}%         %<--------------------------------------------------------------–>  \def\tkzDrawLine{\pgfutil@ifnextchar[{\tkz@DrawLine}{%                                   \tkz@DrawLine[]}}%   \def\tkz@DrawLine[#1](#2,#3){%  \begingroup   \pgfkeys{tkzdrawline/.cd,start = {}, end = {}, start style={}, end style={},}   \pgfqkeys{/tkzdrawline}{#1}   \draw[ /tkzdrawline/.cd,#1] (#2) to%     node [at start,left,/tkzdrawline/.cd,tkzstartstyle] {\tkz@line@start}%     node [at end,right,/tkzdrawline/.cd,tkzendstyle] {\tkz@line@end} (#3);  \endgroup  }%   \makeatother   \begin{document}    \begin{tikzpicture}      \node (A) at (0,1) {};       \node (B) at (5,2) {};       \tkzDrawLine[end = {$\alpha$}](A,B)       \end{tikzpicture}  \end{document}


I have three rows on a Visualforce page. The requirement is that when any value of this field is blank it will show the error message on the page. I have to do this with the help of JSON and by using the following javascript function but I'm stuck. I am new on salesforce and JSON  <script type="text/javascript">    var text = '{"val":['{"TValueFields"}' ] }';     obj = JSON.parse(text);              function findBlank() {             debugger;                        for (i=0; i< obj.length; i++)               {                         var js = JSON.stringify(obj);              if(document.getElementById(js).value == " ")               {                          alert("TValueFields must be select");               }                     i++        } </script>


How to demonstrate that Fierz-like identity for 2-components Weyl spinors?

Consider the 2-components Weyl spinors with the following scalar product \begin{equation}\tag{1} \langle \, \phi, \, \psi \, \rangle = \phi^{\top} \, \sigma_y \: \phi, \end{equation} where $\sigma_y$ is the second Pauli matrix.  To each spinor, we could associate a light-like four-vector of components \begin{equation}\tag{2} n_\psi^a = \psi^{\dagger} \sigma^a \, \psi = \psi_i^{*} \, \sigma_{ij}^a \, \psi_j, \end{equation} where $\sigma^0 = 1$, $\sigma^1 = \sigma_x$, $\sigma^2 = \sigma_y$ and $\sigma^3 = \sigma_z$ are the Pauli matrices.  Now, using explicit components $\phi = (a, \, b)$ and $\psi = (c, \, d)$ (where $a$, $b$, $c$ and $d$ are complex numbers), it is possible to prove the following formula by brute force (it's not too painfull, just a bit long to do): \begin{equation}\tag{3} |\langle \, \phi, \, \psi \, \rangle |^2 = \frac{1}{2} \: \eta_{ab} \, n_\phi^a \, n_\psi^b, \end{equation} where $\eta = (1, -1, -1, -1)$ is the Minkowski metric of flat spacetime.  I'm wondering if there's a simpler proof of (3), using only properties of the Pauli matrices.  Maybe there's another identity related to $\eta_{ab} \, \sigma_{ij}^a \, \sigma_{pq}^b$?


When I catch a higher level Pokemon it normally takes a few poke balls but at least half of the time I get this where it won't catch or escape and it just sits there and load what should I do


In Star Wars lore, who made the first light saber and how was it developed?

Extended universe books allude to a Jedi having to "forge" their own light saber as part of their trials. It seems to be both a rite of passage, and a somewhat holy experience. The connection isn't really explored more than that, though.  How did this forging process become part of Jedi tradition?  Is there a similar tradition for the Sith?  Who made the first light saber, and how was the process developed from one of engineering a weapon to the holy trial for the warrior sect?  Are there any more powerful light sabers within canon?


Why is linear momentum not conserved for a particle in a central force?

I am studying a two-body central force system in which the two particles, one of mass $m$ and one of mass $M$, experience a force directed along the line connecting the two particles.   We can reduce this to a system of just one fictitious particle with reduced mass and a central force. Why is linear momentum not conserved in the CM frame when it was conserved before shifting to the CM frame?


What is the difference between 'Object[] someThing' and 'Object someThing[]' if any?

Often in java code I see people declaring arrays in 2 different ways.   Sometimes it is  Object[] someObjectArray = new Object[...];   And other times I see  Object someObjectArray[] = new Object[...];   I have always used the first one.  I have tried googling this, but I cant seem to word the question correctly, so is there any difference, and of so, how are the two used differently?


16.04 - system hangs at boot time at "Started Update UTMP about System Runlevel Changes"

I have an Acer Aspire One netbook with an Intel Atom CPU and 1GB of RAM. I've been using Ubuntu and a few other distros on it with no problem for two years now. I have used both Ubuntu/Lubuntu/Xubuntu 14.04, 14.10, 15.04 and 15.10 flawlessly, with casual distro changes (Arch Linux, openSUSE, Linux Mint, elementaryOS, Debian). No problems at all. But today I decided to move back to Xubuntu, so I grabbed the "mini" installation ISO from ubuntu.com, wiped out the Debian Jessie partition and installed the system there. After the installation was completed, I installed the "xubuntu-core" metapackage and rebooted. But the system got to a "Started Update UTMP about System Runlevel Changes." message and sits there, with a blinking cursor. I could access other TTYs by pressing Ctrl+Alt+Fx and even startxfce4 (as root), but that issue was really annoying me. So I downloaded a Lubuntu 16.04 ISO from lubuntu.net and went to install it. As I didn't have a DVD or USB drive available, I put it in a backup partition and booted the Lubuntu installation media with GRUB2, using set root=(hd0,msdos4) loopback loop /lubuntu-16.04-desktop-i386.iso linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/lubuntu-16.04-desktop-i386.iso config noprompt noeject initrd (loop)/casper/initrd.lz boot  But it also got stuck in the exact same message. The difference is that now I can't change TTY, but I think it's because it's a live media. Some people suggested it may be a graphics driver problem, but I'm not sure. I also saw a similar problem with some Mageia folks. Can someone help me?


Can't get HTML inside tag using regex (match)

I have this  I'm trying to get the html inside the <app> tag, but can't seem to get it working. How can I fix it? The regex I am using is .match(/<app.*>(.*?)<\/app>/)[1];


Why doesn't Gandalf whip it out in the major battles?

The dragon in LOTR is powerful.  Powerful things can exert lots of power The exertion of lots of power is useful for winning wars one wants to win Gandalf fights in wars he wants to win Gandalf is a more powerful thing than the dragon is. (Evidence: He slays it) So Gandalf can exert lots of power Gandalf does not exert lots of power in the wars he wants to win.    What gives?


Are there other Gringotts branches in the world beside the one in Diagon Alley?

We know about at least one Gringotts in the world, the one in Diagon Alley.There is possibly one in Egypt as Bill Weasley work as a Gringotts curse-breaker there. Apart from Bill's job,is there any other evidence that other Gringotts exist throughout the world.In Harry Potter and the Philosopher's Stone, Hagrid says that Gringotts is the only place to store your gold.He may mean in the UK or in the whole world.  I wonder if the Gringotts in Diagon Alley is the only Gringotts in the entire world?


Why doesn't LaTeX hyphenate words containing accents, e.g. "développement"?

In this MWE, Latex doesn't hyphen the word "développement" and prefer to create a HUGE hbox.   \documentclass[a4paper,12pt,dvipsnames]{report} \usepackage[utf8]{inputenc} \usepackage[french]{babel} \usepackage{lmodern} \usepackage[a4paper, showframe]{geometry}  % Title Page \title{} \author{}   \begin{document} \section{Section}  \subsection{Subsection} \begin{description}  \item [Marhalie Toucse : ]  ingénieure de la plate-forme SORTATZ. Elle réalise   le développement du projet des tex écrit pour lipsum lagae legarc sgsi text text text text text text text text text.  \end{description} \end{document}


Determine from where is "sh" being run under apache www-data user using using PF or NETSTAT

I am working with a compromised Ubuntu 8.04 Plesk 9.5.4 server. It seems that a script on the server is continuously doing reverse lookups to random IPs on the Internet.  I first spotted it during by using top and then noticed flashes of this coming up continuously: sh -c host -W 1 '198.204.241.10'  I wrote a this script to interrogate ps every 1 second to see how frequently this script happens:  #!/bin/bash while : do     ps -ef | egrep -i "sh -c host"     sleep 1 done   The results are that this script runs often, every few seconds:  www-data 17762  8332  1 10:07 ?        00:00:00 sh -c host -W 1 '59.58.139.134' www-data 17772  8332  1 10:07 ?        00:00:00 sh -c host -W 1 '59.58.139.134' www-data 17879 17869  0 10:07 ?        00:00:00 sh -c host -W 1 '198.204.241.10' www-data 17879 17869  1 10:07 ?        00:00:00 sh -c host -W 1 '198.204.241.10' www-data 17879 17869  0 10:07 ?        00:00:00 sh -c host -W 1 '198.204.241.10' root     18031 17756  0 10:07 pts/2    00:00:00 egrep -i sh -c host www-data 18078 16704  0 10:07 ?        00:00:00 sh -c host -W 1 '59.58.139.134' www-data 18125 17996  0 10:07 ?        00:00:00 sh -c host -W 1 '91.124.51.65' root     18131 17756  0 10:07 pts/2    00:00:00 egrep -i sh -c host www-data 18137 17869  0 10:07 ?        00:00:00 sh -c host -W 1 '198.204.241.10' www-data 18137 17869  1 10:07 ?        00:00:00 sh -c host -W 1 '198.204.241.10'   My theory is if I can see who is launching the sh process or form where it's launched I can isolate the problem further.  Can somebody please guide me using netstat or ps to identify from where sh is being run?  I might get many suggestions that the OS is out of date and so the Plesk, but please bear in mind there are some very concrete reasons why this server is running legacy software. My question is aimed at a advanced Linux systems administrators who have in depth experience with security compromises and using netstat and ps to get to the bottom of it.  UPDATE 26 Oct 14:01 SAST  The command grep -lr 'sh -c host' left in the comments left by @ramruma helped me to quickly find the corresponding website running the script. As it turns out the server is not compromised. What is instead happening is there is a forum in that location produced by Powered by SMF 1.1.2 | SMF © 2006-2007, Simple Machines LLC that does a reverse lookup every time someone accesses the board.  It also turns out that the forum is unmaintained and severely spammed and why we initially thought it's compromised is because many of the reverse lookups pointed to foreign IPs known for spamming. Goodness only knows how a website can execute this command, but for the time being I am going to close the issue as harmless.  With regards to the blanket replies I received about "restore from backup" I came to ServerFault to help isolate the issue and I made it clear in my initial request. Sometimes restoring from backup is impractical or even impossible. It's better to figure out the issue or find the compromise in case it might arise in the future.


After opening a pipe to a process with popen, is there a way to kill the process that has been started? (Using pclose is not what I want because that will wait for the process to finish, but I need to kill it.)


I'm trying to find a way with javascript to highlight the text the user selects when they click some odd highlight button (as in highlighted text). It only has to work with either WebKit or Firefox, but it seems to be well nigh impossible because it has to work in the following cases:
this is text

I eat food
   When the user selects from "is text" through "I eat" in the browser (can't just put a span there).  and this case:  this is textmiddle textthis is text   When the user selects from "is text" to "this is" in the browser (even though you can wrap your highlight spans around each element in the selection, I'd like to see you try to get that middle text highlighted).  This problem doesn't seem to be solved anywhere, frankly I doubt it's possible.  It would be possible if you could get the Range that you get from the selection as a string complete with html which could be parsed and then replaced, but as far as I can tell you can't get the raw html of a Range.. pity.


How do we determine the Cut off Probability percent in logistic Regression to segregate customer into good and bad?

New_cust1 <- cbind(New_cust, Prob=predict(fit2, New_cust, type = "response")) View(New_cust1) New_cust1$default <- ifelse(New_cust1$Prob>XXX, 1, 0) sum(New_cust1$default)


How to convert fully connected layer into convolutional layer?

When using a fully-connected network (FCN), I have problem understanding how fully-connected (FC) layer to convolutional layer conversion actually works, even after reading .   In their explanation, it's said that:   In this example, as far as I understood, the converted CONV layer should have the shape (7,7,512), meaning (width, height, feature dimension). And we have 4096 filters. And the output of each filter's spatial size can be calculated as (7-7+0)/1 + 1 = 1. Therefore we have a 1x1x4096 vector as output.    Although the converted layer can give us output with same size, how can we make sure they are indeed functionally equivalent? It's mentioned in the later part of the post that we need to reshape the weight matrix of FC layer to CONV layer filters. But I am still confusing about how to actually implement it.   Any explanation or link to other learning resource would be welcome.


I'm trying to install some programs like Runescape with the (terminal) but I get 404 error. I'm using Xubuntu 16.04 LTS. I'm adding PPA (and try to get sudo apt-get update) but it fails to download and get following errors.  W:The repository '-http://ppa.launchpad.net/hikariknight/unix-runescape-client/ubuntu xenial Release' does not have a Release file  data from such a repository can't be authenticated and is therefore potentially dangerous to use      W:See apt-secure(8) manpage for repository creation and user configuration details., E:Failed to fetch   ppa.launchpad.net/hikariknigh...amd64/Packages 404 Not Found  E:Failed to fetch //ppa.launchpad.net/hikariknigh...-i386/Packages 404 Not Found  E:Some index files failed to download. They have been ignored, or old ones used instead


Induction: $\sum_{k\mathop=1}^n k = \frac{n(n+1)}2$ and $\sum_{k=1}^n k^3 = \left(\sum_{k=1}^n k\right)^2$

Prove by induction that for all $n \in \Bbb N$   $$\sum_{k\mathop=1}^n k = \frac{n(n+1)}2 \quad \text{and} \quad \sum_{k\mathop=1}^n k^3 = \left(\sum_{k\mathop=1}^n k\right)^2$$   I have proved the first part but can anyone show me how to solve the second part?  Thanks.


True Or not: Compact iff every continuous function is bounded

Let $X$ be a topological space. My question is:  If $f:X\to \mathbb{R}$ is bounded for all such continuous $f$, then is $X$ compact. Is is really?  If $X$ is the subset of $\mathbb{R}^d$, then it is clear, beacause with Heine-Borel we get what we want (closed and bounded (with the help of the norm)), but is it true in general? I really hope there exists a non-compact space with the property above.


Photoelectric effect:- Reduction of wavelength increases current?

I did a question in which, the intensity of the incident radiation on a metal surface was kept constant but the wavelength of the photons has been reduced. The question inquired what will be the effect on the maximum photoelectric current? The initial wavelength was smaller than threshold wavelength of the metal surface.  My thinking was since the intensity remains constant, thus the number of photons emitted from the source remains constant and thus the number of electrons emitted from the metal surface. And since number of electrons per unit time isn't changed, the current will remain the same.  However, the answer key stated "Fewer photons (per unit time) so (maximum) current is smaller"   How does decreasing wavelength (equivalent to increasing the energy of photons) result in a fewer photon emission?


Why did the developers add Dex bonus to damage on Dex based attacks?

Why did the developers make Dexterity add to damage on DEX-based attacks? Are there statements by the writers/developers describing why DEX bonus is on damage done as well as to hit rolls? Have they said anything about how to justify your DEX applying as a damage bonus?  Is it like a vital strike?


400 bad request error when using AJAX in mobile device

I am using AJAX with jQuery. In desktop view AJAX working well while using with mobile devices or ipad AJAX is not working. It is showing 400 bad request error.  Here is my code:  jQuery.ajax({          type: 'post',         url: my_ajax_object.ajax_url,         cache: false,         data: {             action: 'shows_month',             currentDate: selectDate,             showLimit: showvalue,         },         success: function(s){             console.log(s);             jQuery('.elements-area').html(s);         },         error: function(er){             console.log(er);         }     }


I think a sentence cannot start with due to. But if I need to say due to this thing something is happening how can I say it?  How can I write the following sentence correctly?     Due to the changes of polygon shapes, similar error cannot be obtained   when computing the residuals with respect to each other.     After posting this question, I found the following link:  (UsingEnglish.com). A post in that thread says     "Due to" is a false friend. It means, caused by - not as a result of, because of or on account of.            Since due to is an adjective, it needs a noun or pronoun to modify. To assure this functioning, the safest place for due to is after a form of the verb to be because there it is always serves as an adjective: "The cancellation was due to bad weather" (due to modifies the noun cancellation).          The most dangerous placement of due to is at the head of a sentence. In "Due to rain" or in "Due to the lateness of the hour" or "Due to a cold I was unable to attend", due to is treated as an adverbial phrase. this is a misuse. A test to determine whether due to is being used correctly is to replace it with "caused by" or "attributed to", which is what due to means. If the replacements make sense, due to is correctly used, as it is in "The explosion was due to [caused by or attributed to] carelessness."         Source: AGU Grammar and Style Guide 3.1    (Casiopea, #2 16-May-2006, 13:56)  Now I am so confused...


CPU Die temperatures reaches 90° C, is that normal?

My Macbook Air 13", Mid 2011, got heated and is slow in working. I noticed that CPU Die temperature reaches 90° C, is that normal?  I've changed my fan recently but still get this issue.


Dual display with MacBook Pro (13-inch, Mid 2012)

I have a MacBook Pro (13-inch, Mid 2012) and would like to set up two 24" Acer monitors so I can have an easier working life. The monitors support CDMI, DVI and VGA, I am new to MacBooks, so I'm not sure where to go or what to do, anything you can advise will be wonderful.  Thanks in advance :)


Are there general methods that can be applied when using the Borel-Cantelli Lemma, to get a statement about a sequence of random variables?

I hope the title in itself is clear, if not allow me to give an example.  In Class my Professor did the following:     Given a sequence $(X_n)_{n \in \mathbb{N}}$ of non-negative i.i.d. RV $X_n \sim X$ with $E(X)< \infty$ then $\frac{X_n}{n} \to 0 $ almost surely   To prove this, it is easy to show that $\sum P (X_n/n > \epsilon) < \infty$ and thus conclude by Borel-Cantelli Lemma that $$P ( \limsup \lbrace X_n/n > \epsilon \rbrace ) =0 \iff P ( \lim \inf \lbrace X_n /n \leq \epsilon \rbrace )=1 $$ But one indeed looks for the answer that $\exists \Lambda \subset \Omega$ with $P( \Lambda)=1$ and for all realizations $\omega \in \Lambda$ we have that $X_n(\omega)/n \to 0$.  In the question  Daniel Fischer gives an answer on how to get an inclusion of the form $\liminf \lbrace ... \rbrace \subset \lbrace \limsup ... \rbrace$.   I do believe that he makes use of the (complementary) statement which says that for $\epsilon >0$ $$ \lbrace \lim \sup | X_n - X| > \epsilon \rbrace \subset \lim \sup \lbrace | X_n -X | \geq \epsilon \rbrace \subset \lbrace \lim \sup |X_n - X | \geq \epsilon \rbrace \tag{*} $$ which gives $$ \lbrace \lim \sup |X_n -X | < \epsilon \rbrace \subset \lim \inf \lbrace | X_n - X | < \epsilon \rbrace \subset \lbrace \lim \sup |X_n -X | \leq \epsilon \rbrace $$    My question(s): 1) Are there more chains of inclusions as in (*) that I should know in order to give statements about the $\limsup$ or $\liminf$ of sequence of Random Variables rather than the $\limsup,  \liminf$ of the sequence of Events?  2) In the above chain of inclusions, does the $\epsilon >0$  on $k$? The Definition gives $$\limsup \lbrace X_n/n > \epsilon \rbrace = \bigcap_{n=0}^\infty \bigcup_{k=n} A_k \text{ where } A_k:= \lbrace X_k/k > \epsilon \rbrace $$ so intuitively I would say that $\epsilon=\epsilon(k)$ varies as $k$ increases.   3) Are there any general techniques you'd recommend to make a statement about the limit of a sequence of random variables using Borel-Cantelli Lemmas?


We are using SQL Server 2016 Enterprise Ed with AlwaysOn Availability Group.  If we want to encrypt our database backups, how do we go about creating the encyrption keys?  For example, do I create the same Certificate used on both primary and secondary?  I am thinking it would be the same cert since the backups could be happening on any of the two replicas.  Anyone have any guidance on this?  I am new to encryption so this is all new to me.  Thanks for any help!


Contradictory messages when question is closed and comments disabled

I spotted this on Super User but I believe the same or similar messages can appear on any SE site. Below are two messages that contradict each other. They appeared in a single post, one under the other:    (For the record, the screenshot is from .) The first message states [emphasis mine]:  Closed. This question […] is not currently accepting answers.  The second message states [again, emphasis mine]:  Locked […]. Comments on this question have been disabled, but it is still accepting new answers and other interactions.  The question at the time was not accepting new answers. The first message was right, the second message was wrong in this matter. The second message should be corrected. It should reflect the actual status of the question. It should not contradict with the first message.


Binomial theorem for non integers ? O_o ??

Could we use the binomial theorem for non integers? This comes from:   $$\sqrt{(a+b)}$$ which I can write as $$(a+b)^{1/2}$$  Could I then use the binomial theorem to figure out the value of this expression?


I'm trying to compile a gnuplot epslatex output (which contains a .tex and .eps file). When I use   \documentclass{article} \usepackage{graphicx} \usepackage{epstopdf} \begin{document} \input{temp.tex} \end{document}   I get the error  ) (C:\Users\Stefan\Documents\temp.tex   ! LaTeX Error: Can be used only in preamble.  See the LaTeX manual or LaTeX Companion for explanation. Type  H <return>  for immediate help.  ...                                                l.2 \documentclass               {minimal} ?    The temp.tex file output by gnuplot has documentclass{minimal}, so my document can't run minimal classes for some reason, why is that?


Why a generic like Node instead of a regular Node

I'm taking Algorithms I on coursera and came across the implementation of a Data Structure called Bag.    However I don't undertand why the use a Node class like this:  private static class Node<Item> {         private Item item;         private Node<Item> next;     }   Why is the Item in there? Why can't I use:  private class Node {          private Item item;         private Node next; }   Is there a difference? Thanks


What is the difference between for each and traditional for loop in Java in terms of shadowing?

This is the code I have:  class HelloWorld {      char[] foo = {'a', 'b'};      // This will compile     void foo() {         for (char foo : foo) {         }     }      // This will not compile     void bar() {         for (char foo = 0; foo < foo.length; foo++) {         }     } }   How come foo compiles but compiling bar fails with:  Error: char cannot be dereferenced   What is the difference between the two loop declarations that makes loop in foo compile but bar fail?


Where does the Mac store account pictures?

I took a picture to add to my account on Mac.   Now I want to use it on messenger, but I can't find it. On the account config, it's too small. I need to find the original.   Where are the accout pictures stored on a Mac?


How do I enable Cortana after the Anniversary Update (1607)?

The Windows 10 Anniversary Update appears to have killed Cortana. How do I bring her back?  The search screen is the old, standard one, and the search icon is a magnifying glass instead of the Cortana circle.    Cortana settings let me choose language but reports a region mismatch even though both are the same. There are no other Cortana-specific options there.


What weapons to use to kill the Destroyer?

I'm planning this speed run with a friend, our situation now is that we've just killed the Wall of Flesh, are geared with Molten gear (Armor, Imp, Bow, Sword, etc.). We're at 300 HP, but we'll probably make sure we are at 400. Our plan is to kill the destroyer once, to get at least 20 Souls of Might, to craft the Megashark. We've tried various weapons (Molotov, Grenade, Minishark, Molden Fury), but the problem is that the DPS is just not enough. Next step is that we'll try to go pick up a Handgun from the dungeon to get a Phoenix Blaster + Explosive shot. So I'm wondering if you have a suggestion for us on what weapon to use for this, keep in mind that speed is of the essense, part of our challenge is in fact not taking 1-2 hours to craft 2 Titanium / Adamantium armors and such.


Dot Product and Cross Product: Solving a set of Simultaneous Vector Equations

I was wondering if $\mathbf{A}\times\mathbf{C}=\mathbf{B}$ and $\mathbf{A}\cdot{\mathbf{C}}= p$, is it possible to express C in terms of A, B, and p?  Note: A, B, C are vectors and p is a scalar.  Sorry if this question has been asked before. If so, can anyone give me a link to it?


How to map right windows key to backspace?

BackSpace key is out of range of my right hand, and everytime I work with text editor in such conditions where I need a backspace key stroke, it makes me look at my keyboard, and so disturbs my rhythm of typing.  I hardly use my Right Windows key. I want to map it to perform as backspace key.   (I have a US standard layout keyboard.)


I installed Mac OSX theme for Ubuntu 13.10 (I am a new Ubuntu user), and I am wondering how I can remove (not hide) the left menu bar, and move all programs to the bottom menu bar (Max OSX theme).


Rendering to movie: Under File format there are no options for h.264, Qicktime or MPEG

I just downloaded Blender, testing to render animation. But there seem to be something missing under Output > File format. Here is my version     Greatful for help...:-I!


Why are mods declining flags to add [featured] to pertinent questions?

I as well as other users have flagged some of the recent questions about ads and tracking users, so people can have some forewarning before their information is all over the internet.  However, the flags have all been declined, with this canned response (at least on my flags):     flags should only be used to make moderators aware of content that requires their intervention   Of course, this definitely needs moderator intervention, because normal users cannot add  to posts.  I'm posting here because I'm trying to get some perspective on this situation and why mods aren't letting users know about information that they may want to know.  Here are my two flags:  On :     [featured] -- this will be very important to a lot of users.   On :     Can this be [featured]? It's important and people need to see it (it involves fingerprinting). They also need to know to have an adblocker enabled.   Why have flags of this type been declined?


Extending Root Partition By Deleting Swap Partition

Currently, I am running low on space on my root partition (I need more space to execute the 20.04 update). I have a 14.9 GB swap partition, and a half-filled home partition. I'm thinking I would delete the swap partition, extend my root partition into some, or all of the remaining space, then make a new swap partition by resizing my home partition. This is currently what my  looks like, the first few partitions are for my windows dual boot. How would I accomplish this?


I'm looking for a function $f:\mathbb{R}\longrightarrow\mathbb{R}$ which is surjective on every open subset of the real line.  Obviously this calls for an inductive construction. But how do I do that ensuring I don't break anything later in the process? I was thinking about putting all the open subsets into a sequence of length continuum, and then setting $f_0$ surjective from $U_0$ onto $\mathbb{R}$ and $f_{\alpha}$ surjective from $U_{\alpha}\setminus\bigcup\limits_{\gamma < \alpha} U_{\gamma}$ onto $\mathbb{R}$ anyhow I want (if it is nonempty). I thought this would be a well defined construction, as this difference would always be non-countable if not empty. But now I see that there is no contradiction in saying that, say, $U_5=(0,1),\ U_6=(1,2),\ U_7=(\frac{1}{2},\frac{3}{2})$ and in that case... I'm not sure what to do.  Please, help.


sudo apt-get update failes with an Hash Sum mismatch error

As can be seen on the title, I got the "Failed to fetch... Hash Sum mismatch" Error. I have tried this method:   Deleting /var/lib/apt/lists/* does not work... Thinking, if I'm behind a proxy, I tried fixing "Hash Sum Mismatch" like this:   By Creating a file /etc/apt/apt.conf.d/99fixbadproxy with this content  Acquire::http::Pipeline-Depth 0;  Acquire::http::No-Cache true;  Acquire::BrokenProxy    true; I tried several other solutions provided on askubuntu however, it doesn't work.   Have a look at my error on the terminal.


To Find $a$ such that  $2^{1990} \equiv a\pmod {1990}$.  $1990 = 2 \times 5 \times 199$. Now $a \equiv 0 \pmod {2}$, $a \equiv 4 \pmod{5}$ and $a \equiv 29 \pmod{199}$. Taking first two together we get $a \equiv 4 \pmod {10}$.  $199x \equiv 1\pmod {10}$ has a solution $x =-1$ and $10x \equiv 1\pmod{199}$ has a solution $x = 20$.  Thus using Chinese Remainder Theorem we have,   $a \equiv 4(-1)199 + 29(20)10 \equiv 5004 \equiv 1024\pmod {1990}$.  Thus our $a = 1024$.  Is the solution correct? Is there any better proof?


This question is asked often in Ask Ubuntu, sometimes with few hints about the situation. There are many reasons a persistent USB might not boot BIOS  USB not set as first hard drive in BIOS  Problems with BIOS or UEFI boot partitions or files.  Secure Boot not turned off  Drive not compatible with computers BIOS or UEFI boot mode  Incorrect partition table  Out of date BIOS/UEFI firmware  Junk in volatile memory   GRUB  Incorrect root partition in grub  Incorrect path to ISO in grub  Incorrect persistent-path, (if used), in grub  Grub menuentry structure not suiting OS  Incorrect file type for vmlinuz and initrd (.efi and .lz)  The word "persistent missing from grub.cfg, txt.cfg, syslinux.cfg or text.cfg   PERSISTENCE (CASPER-RW & HOME-RW)  Persistence partition is not ext file system  Persistence file not on FAT filesystem  Persistence file/partition reused from different version  Persistence file full of data, or file update attempted   HARDWARE  Corrupted flash drive  Bad flash drive  Not enough RAM to run Ubuntu  Bad or incorrect USB socket  Incompatible computer CPU  Incompatible computer GPU  Computer does not meet minimum specs, lighter version of 'Buntu required  Motherboard voltage irregularities  Motherboard BIOS limitation with multiple USB devices  Computer does not boot USB's. Plop boot manager required.   SOFTWARE  Bad MD5SUM / Corrupt ISO file  Modified or corrupted ISO9660 partition  USB removed from computer before ISO file is completely copied  Out of date Boot drive creation tool  User inexperienced with boot procedure   Please let me know of any reasons I have missed. An up-vote for any currently valid original reason not on the list, A green check for best original list additions


Newton's third law, why does this body move?

while i have tried reading explanations for why newtons third law doesn't mean objects can't move such as this one:  I still do not understand how to apply them to the system I'm about to describe:    (Suppose the system is in space so friction isn't present)  Force F is pushing object A, object A thus pushes object B with force equal to F. According to newtons third law object B will exert an equal force on object A in the opposite direction. So now on Object A, two equal forces are acting in opposite directions, so it should not move. my question is why does object A end up moving after all?


Request for tool recommendations are off-topic, but

...but this question:  is still actively collecting answers; has received comments like "This is a spectacularly useful thread. Thanks!"; has not received even a single close vote; yet clearly flies in the face of :     Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it.   I think that this particular thread helps a lot of people in the community; I would definitely not want it to be closed. However, I think that if this exact question were asked today (instead of 4 years ago), it would be closed in short order.  I understand perfectly well why this kind of question often leads to undesirable opinion-mongering. However, considering how useful this particular thread itself is, would there be some value in revising the criteria for what can be asked? Perhaps a way could be found to make room for this kind of thread when it actually is a valuable resource for the community? (Note that the  directs that community to SO for questions about programming tools. There appears to be no place in the StackExchange network for this kind of thread.)


When I use the mobile app to vote for an answer that was awarded a bounty,  the bounty is no longer shown until I reload the answers.


How to do liklihood ratio test comparing two models using pchisq

I am simply asking that how to do likliehood test for 2 models using pchisq. I have a question in which it is asked that i have to do  likelihood ratio test comparing the models. I have calculated models as model1 <- glm (val ~ val2, family=binomial, data=xyz) model1 <- glm (val ~ val2 + val3 + val4, family=binomial, data=xyz)  now how would i do the likli hood test on these 2? I see the formula is 1 - pchisq(glm1$null.deviance - glm1$deviance, df = (glm1$df.null - glm1$df.residual))  But this is doing only for 1 model (which is stored in glm1 variable). Is the question asking me to do test independently and then compare the output of 2 models? Or there is a way in which i can input 2 models in a funciton to get the result?


The first time I knew about the hyperbolic function was when I was studying the derivatives. And I know that the derivative of   $\sinh x=  ( e^x - e^{-x} )/ 2$ , but i still confused with what are they really are? and how did we get them and for what we are using them?  Thanks very much, and i hope that wasn't a long question.


If you buy a physical Switch title, is it region-locked?

If I buy a physical copy of a Nintendo Switch game, will I only be able to play it in the language/locale of that physical copy? Or does owning that copy grant me the ability to play it in ALL language / region settings? I heard that the Switch is region-free, but I also know there can always be fine-print.


New printer HP 5540 envy he scanner doesn't work


How can I check when I can (statistically) fly to given locations most cheaply?

There are many sites where I can search for a particular flight with various date ranges and compare the prices.  But, say, I want to go from Warsaw to New York, or London, or anywhere else (the location is just an example). But I have 100% flexibility when I'll go. How can I check in which part of the year the flight prices on the given route tend to be the most attractive?  I'm aware the prices are very volatile, but if there's a general trend that the flights to London are cheapest in May, and to New York in October, it would greatly help me to start planning.


Should edits with only minor code improvements be accepted. As an example, I'm reviewing an edit that changes all double quotes to single quotes and renames a variable in some javascript. With the exception of the variable rename (which is not entirely necessary), the edit is frivolous. Should I accept on the merits of a debatable variable name change?


Someone misrepresented my work in a published paper

Its a conference paper that broadly says:  "There is X, Y, Z, Biguri et al, articles out there, but here is a table with each of the works and their limitations, and why ours is better"  And then lists a bunch of things on my published article (about a software tool) claiming it does not contain several features. The problem is, the tool has and always had most of the features they say it hasn't. They are published and clearly demoed and showcased in the webpage.   Their paper has some credit, it is still good work and its not invalid because of their mistakes. But it is seriously misrepresenting my work.  What should one do in this case?   I was thinking on politely emailing them to let them know about their mistakes, I assume its not a malicious mistake, but more the fact that they did not take the time to properly do research. Is there anything else I can/should do?


Quick way to compute the polynomial satisfying given conditions

Let $f(x)$ be a polynomial such that $$\lim_{x \to \infty}\frac{x^4f(x)}{x^8+1} = 3, f(-6)=37, f(-1)=2,f(2)=5, f(3)=10$$ Then:  Find the value of $f'(3)$ Find the value of $$\lim_{x \to -6} \frac{f(x)-x^2-1}{3(x+6)}$$   Both of the sub-questions require finding $f(x)$, so I'll proceed to find that. According to the first limit, $f(x)$ is a fourth-degree polymial with the leading coefficient as $3$. We can rewrite $f(x)$ as: $$f(x) = 3x^4 + ax^3 + bx^2 + cx + d$$ Given four values of $f(x_i) = y_i$, substituting them gives us a system of 4 equations in $a,b,c,d$: $$\begin{align} f(-6) = 37 &= 1296\times3-216a+36b-6c+d \\ f(-1) = 2 &= 3-a+b-c+d \\ f(2) = 5 &= 48 + 8a+4b+2c+d \\ f(3) = 10 &= 243 + 27a + 9b + 3c + d\\ \end{align}$$ This is extremely tedious without using a calculator/computer, so are there any easier ways to compute $f(x)$ or solve the two sub-questions? Preferably a method that does not involve solving the given system of equations. I am aware of Lagrange interpolation, but using that for the given values gives me a third-degree polynomial, which does not satisfy the first condition.


I think in quantum mechanics we assign to each system a specific Hilbert space i.e. if systems are different then their Hilbert spaces are different. Is this true? If not why? For differernt system I mean their hamiltonians are different.


Abelian Group Criteria and counterexample

I am reading I.N.Herstein-Topics in Algebra  I am able to solve the following exercise: If $G$ is a group in which $(a.b)^i=a^i.b^i$ for three consective integers $i$ for all $a,b\in G$, $G$ is abelian.  For solving this problem, I arrived at an intermediate step/expression $(a^{i-1}.b=b.a^{i-1})$ of the proof using two consecutive integers for which the relation holds.  Question:     Show that the above conclusion does not hold if we assume the relation   $(a.b)^i=a^i.b^i$ holds only for two consecutive integers.   Here, I think I need to find an example where the expression $a^{i-1}.b=b.a^{i-1}$ holds but $b.a\neq a.b$.  So, I think that a subgroup of $M_n(\mathbb{F})$ should be an example where $N^{i-1}=I\enspace \forall N\in M_n(\mathbb{F})$.  But I am unable to find the above-desired group. Can anyone help me to find it?  Also, other examples would also be appreciated.


I'm trying to run a Python script every hour although it doesn't seem to be executing.   The command in crontab -e is:   0 * * * * /usr/bin/python3 /home/ubuntu/Python_Script/main.py 2>&1 /tmp/pythonlog.log  The script isn't running and the output log isn't getting created.  Running grep CRON /var/log/syslog doesn't give anything that I can see indicating that the script isn't being run.  Here's a small part of the output.  Sep 15 18:00:01 ip-x-x-x-x CRON[1702]: (ubuntu) CMD (/usr/bin/python3 /home/ubuntu/Python_Script/main.py) Sep 15 18:00:01 ip-x-x-x-x CRON[1701]: (CRON) info (No MTA installed, discarding output) Sep 15 18:17:01 ip-x-x-x-x CRON[1725]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly) Sep 15 19:00:01 ip-x-x-x-x CRON[1889]: (ubuntu) CMD (/usr/bin/python3 /home/ubuntu/Python_Script/main.py 2>&1 /tmp/pythonlog.log) Sep 15 19:00:01 ip-x-x-x-x CRON[1888]: (CRON) info (No MTA installed, discarding output) Sep 15 19:14:44 ip-x-x-x-x cron[1996]: (CRON) INFO (pidfile fd = 3) Sep 15 19:14:44 ip-x-x-x-x cron[1996]: (CRON) INFO (Skipping @reboot jobs -- not system startup) Sep 15 19:17:01 ip-x-x-x-x CRON[2016]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)   This is being run on an AWS Lightsail instance, with Ubuntu 18.04 installed.  I'm wondering what is going wrong, and how to fix it.  All help is appreciated, thanks!  SOLVED  Turned out to be an error with the Python code, worked on my laptop but the working directory seems to be different on the AWS server. For some reason os.getcwd() returns /home/ubuntu/ and not /home/ubuntu/Python_Script.


How do I shrink my unmounted root partition?

I'm running gparted on a live USB, there isn't a key next to the root partition. Yet I when I click resize, the menu that pops up doesn't allow me to change the size.  Here is a screenshot of gparted:


The list of related questions is shown empty

At the moment, any question that I check returns empty list of related questions. I see just a header called "Related" but no questions shown below that. I have checked this on multiples sites and also while not logged in. (At the moment I do not have the possibility to try it from a different computre or from different IP - but maybe other will confirm whether they see the same thing, to check whether this is just my local problem.) Here are some screenshots showing what the sidebar looks like. The first one is from Meta Stack Exchange:  From Mathematics Stack Exchange:  From MathOverflow (this site does not display HNQs in the sidebar):


Should "in-cabin" be hyphenated in "the dogs must ride in-cabin on the airplane"?

Would the term in-cabin be hyphenated or not? As in, the dogs must ride in-cabin on the airplane.


Unable to populate recycler view due to null pointer exception on runtime

I'm trying to populate a recycler view and fetching data from the server, but the app is crashing and showing below error. I am unable to get where actually error is: 2021-02-15 13:28:02.425 21513-21513/com.app.itunes E/AndroidRuntime: FATAL EXCEPTION: main Process: com.app.itunes, PID: 21513 java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference     at c.b.a.h.b$a.b(:93)     at c.b.a.h.b$a.a(:76)     at androidx.lifecycle.LiveData.c(:133)     at androidx.lifecycle.LiveData.d(:151)     at androidx.lifecycle.LiveData.k(:309)     at b.m.p.k(:50)     at c.b.a.d.b$a.b(:50)     at f.h$b$a$a.run(:71)     at android.os.Handler.handleCallback(Handler.java:883)     at android.os.Handler.dispatchMessage(Handler.java:100)     at android.os.Looper.loop(Looper.java:214)     at android.app.ActivityThread.main(ActivityThread.java:7356)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)  Below is my code: VideoRepository.java public class VideoRepository {  Application application; MutableLiveData<List<Result>> myVideos = new MutableLiveData<>(); List<Result> videos = new ArrayList<>();  public VideoRepository() {     this.application = application; }  public MutableLiveData<List<Result>> getMyVideos() {      Retrofit retrofit = RetrofitClient.getInstance();     ApiService apiService = retrofit.create(ApiService.class);      Call<Video> videoList = apiService.getTracks("Michael+jackson", "musicVideo");      videoList.enqueue(new Callback<Video>() {         @Override         public void onResponse(Call<Video> call, Response<Video> response) {              Video video = (Video) response.body();              if(response.body() != null){                 videos = video.getResults();                 myVideos.setValue(videos);             }         }          @Override         public void onFailure(Call<Video> call, Throwable t) {             Toast.makeText(application,t.getMessage(),Toast.LENGTH_SHORT).show();         }     });      return myVideos;    } }  VideoViewModel.java  public class VideoViewModel extends ViewModel {   VideoRepository videoRepository;   public VideoViewModel(){       videoRepository = new VideoRepository();  }   public LiveData<List<Result>> getVideoRepository() {     return videoRepository.getMyVideos();   } }  VideoFragment.java  private void loadTracks(){         fragmentVideoBinding.videoRecycler.setHasFixedSize(true);        fragmentVideoBinding.videoRecycler.setLayoutManager(new GridLayoutManager(getActivity(),2,GridLayoutManager.VERTICAL, false));         videoViewModel = new ViewModelProvider(getActivity()).get(VideoViewModel.class);         videoViewModel.getVideoRepository().observe(getActivity(), new Observer<List<Result>>() {            @Override            public void onChanged(List<Result> results) {                      if(results.size() > 0){                          fragmentVideoBinding.animEmpty.setVisibility(View.INVISIBLE);                         videoList = results;                         VideoAdapter adapter = new VideoAdapter(videoList,getActivity());                         fragmentVideoBinding.videoRecycler.setItemAnimator(new DefaultItemAnimator());                         fragmentVideoBinding.videoRecycler.setAdapter(adapter);                     }                     else{                         fragmentVideoBinding.animEmpty.setVisibility(View.INVISIBLE);                         Toast.makeText(getActivity(), "Nothing to show", Toast.LENGTH_SHORT).show();                     }              }        });   }  Why is my app crashing?


how to find the location of chrome User Data folder from the omnibar?

If I want someone to tell me the location of their Google Chrome User Data folder, is there a line they can paste in the omnibar to find out? In Firefox, I can type about:cache and it lists the location. But in Chrome it lists the content of the cache, not the location of the folder.


Homeomorphism from square to unit circle

Can we find a homeomorphism from the square $Q_2$ of side length $2$ centered on the origin and the unit circle $S^1$?  We can easily define a map $r:Q \longrightarrow S^1$ by  $$(x,y) \mapsto  \bigg(\frac{x}{\sqrt{x^2+y^2}},\frac{y}{\sqrt{x^2+y^2}} \bigg)$$ which is a radial projection onto the unit circle, but how can we define $r^{-1}$ and show that it is continuous?   Thoughts  I think we may define the inverse map as   $$(x,y) \mapsto \bigg(\frac{x}{\sqrt2\max{│x│, │y│}} , \frac{y}{\sqrt2\max {│x│, │y│}}\bigg)$$At least intuitively this maps to a square, and the $\frac{1}{\sqrt2}$ term scales appropriately. However, how can we demonstrate these are continuous maps, thus demonstrating that $Q_2$ and $S^1$ are homeomorphic?  Any help would be appreciated. Regards, MM.


I am a bit afraid that google will punish us as of duplicate content. Let's say there are three domains.    service_a.example service_b.example mycompany.example   All three domains shall share the same Colors/Styles/CI, so I want to have all sources in one place. If I change the button color, all three domains should update.  Idea: mycompany.example is the main domain which has a path /service_a and /service_b. I want to configure NGINX that way that if a user visits service_a.example the content of mycompany.example/service_a gets served. My idea is just to add a canonical link from https://service_a.example to https://mycompany.com/service_a.