When an object is rolling (no slipping) on a slope there should be a frictional force  which causes rotation. But when we use power insulation philosophy, we haven't considered about an energy loss against frictional force. So I have a doubt that when the object is rolling without slipping is there any connection between work done by force of friction and rotational kinematic energy?

I have read various answers , on PSE and elsewhere , and most of them explain that the point of contact of the rolling object undergoes 0 instantaneous displacement in the direction of friction, I agree , but then there is a feeling that the friction does provide a torque , so how can it do 0 work . ( The pure rolling here is under a constant external force on the object so friction does act ).


I have one variable which I store my full name and I want to break my name.  let fullname ="Praveen Tripathi";   I want to this type :-  let firstname ="Praveen"; let lastname = "Tripathi";

I have this string  'john smith~123 Street~Apt 4~New York~NY~12345'   Using JavaScript, what is the fastest way to parse this into  var name = "john smith"; var street= "123 Street"; //etc...


I am trying to create contents of a document and I am facing problem with numbering the subsubsection{} part. I am getting the following contents:  I want the subsubsections to be numbered like 1.1.1.1, 1.2.1.1 and so on in case I enter more of them. Below is the latex script: \documentclass[a4paper]{report}  \begin{document}      \tableofcontents          \chapter{Introduction}     \section{Section 1}     \subsection{Subsection 1}     \subsubsection{Subsubsection 1}     \section{Section 2}     \subsection{Subsection 2}     \subsubsection{Subsubsection 2}  \end{document}

So we have something like:  \documentclass{article} \setcounter{secnumdepth}{2} \setcounter{tocdepth}{2} \usepackage{amsmath}  \begin{document}  \tableofcontents  \section{Brushless Motor Fundamentals} \subsection{Brushless Motor Operation} \subsubsection{DC Motor Operation} Torque is generated in DC motors from the magnetic force, also known as the Lorentz force, which is produced when an electric current is passed through a coil in a magnetic field. This force is given by $F=q[E+(v\times B)]$, where $F$ is the force perpendicular to the coil, $E$ is the electric field in the coil, $B$ is the magnetic field, and $v$ is the velocity of the charged particles in the coil. From mechanics, torque is $\tau=F\times r$.  \section{Brushless Motor Fundamentals 2} \subsection{Brushless Motor Operation} \subsubsection{DC Motor Operation 2} If the electrical force is ignored and the remaining magnetic force is used, with the assumption that $v$ is perpendicular to $B$, we find that $\tau=qvBrsin\theta$.  \end{document}   How to show subsubsections and paragraphs in TOC?


How to find all integer solutions for the equation $y = \frac{a+bx}{b-x}$, where a and b are known integer values? P.S. x and y must be integer at the same time

My proof: By the way of contradiction, suppose that we found $(x,y) \in \mathbb N^*$ satisfies:$$\frac{x+y}{xy}=5$$ So : $$x+y=5xy \\ \iff x=5xy-y \iff x=y(5x-1)$$ Since $x\in \mathbb N^* $ so the minimum value of $5x$ is $5>1 \implies y\mid x$ By the same method we have: $$y=x(5y-1) \implies x\mid y$$ $x\mid y, y\mid x \implies x=y$, Now we can write the original equation as : $$\frac{2x}{x^2}=5 \iff 2=5x \implies x\notin \mathbb N^* $$ Therefore there is no solution to this equation: $$\frac{x+y}{xy} =5$$ Does this considered a proof?


I am confused about virtual destructor. I know if we create instance of derived class using a base class pointer like the following  Base *p = new Derived;   But if we delete this now  delete p;   Why would it not delete the object properly? What is p pointing towards ? I know that making the base class destructor virtual would kill the object properly but how does this thing conceptually work ? It has something to do with heap ? As a result of the statement   Base *p = new Derived;   What is being stored in the stack and what's on the heap ? And by simply deleting (with non virtual base destructor) why it's not calling the derived destructor. I'm just confused conceptually.

I have a solid understanding of most OOP theory but the one thing that confuses me a lot is virtual destructors. I thought that the destructor always gets called no matter what and for every object in the chain. When are you meant to make them virtual and why?


Is this sentence correct?     I don’t think Linda would have approved of my  sending the picture; but I did it anyway.   Specifically, is of my sending the picture correct?

I assume that the following sentences are grammatically correct:   He resents your being more popular than he is. Most of the members paid their dues without my asking them. They objected to the youngest girl's being given the command position. What do you think about his buying such an expensive car? We were all sorry about Jane's losing her parents like that.   I'm still getting used to this possessive gerund structure. It sounded so weird to me at first. Is the structure used in both formal and informal contexts? Are there any alternative structures that result in the same meaning and are more frequently used? (Examples taken from )


Is there a Latex symbol to represent the inverse angle of a complex number? Since, from what i see, this isn't very well known, I'll post a picture of my math book which uses it below (Engineering Mathematics - Stroud). Thanks.

I am trying to draw a partial box around one or more words within a paragraph--that is, a rectangle with one or more sides missing. I have read the documentation for the fancybox package and it doesn't seem to be able to do what I want. I was able to produce thus ugly hack:    That's just a vertical bar | followed by a word with \overline and \uline. The trick is to connect the vertical and horizontal lines so that you have a rectangle missing just one side.  Is there an easy, general way to do this, perhaps with Tikz? I don't know enough about that package to be able to do this myself, but I'm wondering if there might be other solutions too.


In one of the grammar books I study I found a following example: In my previous job I was confined to doing only one thing. I'd say that confined to do is the correct way to say it. I always thought that we can never use to + gerund, or can we? And if so, then what is the rule? Thank you in advance.

Some verbs are followed by ing, e.g. I enjoy swimming. We can't say I enjoy to swim. Likewise, some verbs are followed by to, e.g. I decided to make a plan.   Which particular verbs are followed by ing and to? Can you please provide a list for that?  Moreover, which verbs can be followed by both without having the meaning changed?


Every form of hypercomplex number I have seen (including the complex numbers) lose some important algebraic property. Why is that? Is there a pattern to what we lose?

Motivating question:    I'm aware that one can construct a hierarchy of number systems via the Cayley–Dickson process:  $$\mathbb{R} \subset \mathbb{C} \subset \mathbb{H} \subset \mathbb{O} \subset \mathbb{S} \subset \ldots $$  "Reals" $\subset$ "Complex" $\subset$ "Quaternions" $\subset$ "Octonions" $\subset$ "Sedenions" $\subset$ $\ldots$  and that at each step you're given a multiplication table that tell how the elements interact. As you move up the ladder, certain "nice" properties are lost: ordering,  commutativity, associativity, multiplicative normedness, etc... Given the multiplication table, you can show that these properties don't hold.   Eric Naslund noted that "the first 4 are very special as they are the unique 4 normed division algebras over ℝ", no surprise then that these $2^n$-ions have found quite a bit of use. I'm interested in the sequence itself however, irrespective of how useful a $2^{256}$-ion might be (ducenti-quinquaginta-sex-ion?).   I feel like something deeper is going on here though that I don't understand. Why are these particular properties lost at each step? Is it possible to quantify the process such that, at the $2^n$-ion you can say something about the symmetry of the multiplication table*?  * I'm making an ansatz that there is a connection between the symmetry of the multiplication table and these "nice" properties.


I would like to assign apps to workspaces, so every time an app is launched, it starts in specific workspace that it's assigned to. I'm using XFCE4 on Arch Linux.

I need to start a GUI application [Lotus Symphony] on a workspace different from the currently used one. [ex.: there are 4 workspaces on a GNOME desktop.]  Q: How do I do this?   p.s.: It's needed because Lotus Symphony's first start after a reboot is very, very slow, but after it's been used once, it starts very quickly. I think it caches itself. That's why I want to start it at every boot on a different workspace, so it will be fast later if I need to use it.


I am quite new to latex and I would like to ask you for help with my bibliography.  I am using XelateX on TeXworks in Texmaker. I am writing my thesis based on a template for my university. It is said I need to use biber. The preamble says this:     % Bibliography (references)     \usepackage[backend=biber,                 style=numeric,                 %backref=true,                 abbreviate=true,                 dateabbrev=false,                 alldates=long]{biblatex}   I have downloaded it but can't figure how to compile my file with biber. And I am getting the following message in my Texworks:   I did apply the steps from the previous topic: but it did not resolve my problem. The warnings I get are the same and I get no bibliography.  What should I do to make it work?  I appreciate your help.  Cheers KK  Edit 1: I compiled my .tex file with XeLateX, then Biber and get the following information: Process started  INFO - This is Biber 2.1 INFO - Logfile is 'Thesis.blg' INFO - Reading 'Thesis.bcf' INFO - Found 1 citekeys in bib section 0 INFO - Processing section 0 INFO - Looking for bibtex format file 'bibliography/Bibliography.bib' for section 0 INFO - Decoding LaTeX character macros into UTF-8 INFO - Found BibTeX data source 'bibliography/Bibliography.bib' WARN - Entry ASPS does not parse correctly ERROR - BibTeX subsystem: C:\Users\uqkkepa\AppData\Local\Temp\lU5ArF2aqU\Bibliography.bib_5208.utf8, line 1, syntax error: found "2011", expected "," INFO - WARNINGS: 1 INFO - ERRORS: 1  Process exited with error(s)

Running the minimal example  \documentclass{article} \usepackage{filecontents} \begin{filecontents*}{\jobname.bib} @ARTICLE{example,   author  = {Other, Anthony Norman},   title   = {Some things I did},   year    = {2014},   journal = {J.~Irrep. Res.},   volume  = {1},   number  = {1},   pages   = {1-10} } \end{filecontents*} \usepackage[backend=biber]{biblatex} \addbibresource{\jobname.bib} \begin{document} Hello\cite{example}. \printbibliography \end{document}   I get the warning There were undefined references.  I have read  and know that I need to run:   LaTeX Biber LaTeX   However, my editor is only set up to run BibTeX. How do I go about setting up my editor/IDE to be able to run Biber, and how do I run the LaTeX/Biber/LaTeX cycle?  Answers (sorted alphabetically by editor name)                    Answer guidelines   Each answer should be for one editor. If the editor is cross-platform, if possible give a single answer with notes covering the minor platform variations. Please edit the question to include new answers in the 'link list' Each answer should be 'stand alone', i.e. don't say 'It's almost the same as editor Y but ...' for the editor part Instructions for 'build tools' such as arara or latexmk are welcome but should explain how to set up the editor in question as not all editors allow simple addition of arbitrary tools


I often pull out the USB stick without having to first eject USB, but so far I have not had any problems.   Would this lead to problems in the future?

When you unplug an USB drive without unmounting, your OS warns you about how dreadful could be such operation for your devices (I'm on OSX).  I usually follow the advice, unmounting before unplugging, but it happened many times (thousands) that, at the end of my tasks, I just unplugged (Hd storage, Cell phones, etc..) and I never ever noticed corrupted data on my devices. Am I lucky or can this annoying warning just be ignored?


In the movie Star Wars: Revenge of the Sith, I am wondering why Darth Sidious didn't detect Yoda's presence inside the Galactic Senate building until Yoda walked into his office and also as to why he was surprised by Yoda coming there. Darth Sidious was someone who liked to brag a lot about how he was able to foresee future events, so its a bit of mystery to me as to why he was surprised by Yoda coming there and also as to why he hadn't foreseen having such a huge battle with Yoda inside the Galactic Senate building. I think this was a mistake on the part of George Lucas. I think the way he should have written this scene in the movie is that Yoda walks into his office, takes out the two guards, Darth Sidious then turns his chair towards Yoda and says, "Master Yoda, you survived just like I had foreseen. You should not have come back here, I highly suggest that you surrender!" Yoda refuses and the two of them go on to battle just like it was shown in the movie. Why didn't Darth Sidious detect Yoda inside the Galactic Senate building before Yoda walked into his office?

In Return of the Jedi, Luke and Darth Vader both sense each other's presence on the moon. In The Force Awakens, Kylo Ren   senses Han Solo on the Starkiller Base  Is it possible to sneak up on a powerful Force user? Or do you have to be   related to them  or significant to them in some way to be detected? Are there any examples of a Force user not sensing someone (in canon), or any successful attempt at disguising someone from a Force user? To clarify, I am talking about physical presence, not Force ability.   Han Solo doesn't have the Force, but Kylo sensed him anyways


Let A be a finite set and let B be a subset of A with |A| = n, |B| = m and 0 < m < n. Find a formula for the number of subsets of A that contain B and prove your statement.  I am confused. Is this just m ^ n? Thank you in advance.

Task is:  Let $A$ be a finite set and let $B$ be a subset of $A$ with $|A|=n$,$|B|=m$ and $0< m < n$.Find a formula for the number of subsets of $A$ that contain $B$ and prove your statement.  I assume this is $2^m$ + something. $2^m$ would count the subsets containing only elements of $B$, but i'm not sure how the sets of the form $(a_1,a_2,b_1)$ or similar would be counted. I'm having troubles with this so help would be appreciated.


I am working on a practice exercise using Python 3.7.2.  The program takes the input, total sales in this problem, and calculates and display the total profit.  Is there a way to pre-format the input float so looks more like currency, with a dollar sign, commas separating the thousands, and two digits at the end for cents?  Currently, the program works fine as long as I enter any given integer.  The output appears just like it should, but the input just appears as a large row of numbers.  The input should appear as $23,987,456.00.  def main():     display_message()      # Get sales     total_sales = float(input("Enter the total sales: "))      # Calculate annual profit     total_profit = total_sales * annual_profit     display_results(total_profit)  def display_message():     print("")     print("This program determines the annual profit from the total sales, and")     print("displays the projected amount.")     print("")  def display_results(total_profit):     print("")     print('The total profit is: $', format(total_profit, '6,.2f'))  # Define global constants and call main annual_profit = float(0.23) main()

I am looking to format a number like 188518982.18 to £188,518,982.18 using Python.  How can I do this?


I have a dual boot windows 10 and Ubuntu on my system and on  grub I am getting some unwanted boot listings.  I want only my windows and Ubuntu boot options on my grub and remove the unwanted efi boot files. How can I?   I cannot upload screenshot of my PC as I don't have 10 reputation to do so. :P

This is what my GRUB 2 menu looks like so far:  I want to do a few things here:  I want to rename "Windows Boot Manager (on /dev/sda1)" to just "Windows 8.1". I'd like to rename "Ubuntu" to "Lubuntu 14.04.1". I'd also like to switch the order of the options to this:  Windows 8.1 Lubuntu 14.04.1 Advanced options for Lubuntu    (Windows will be the default OS) If it helps in any way, I'll explain the steps I took prior to this, since I am very new to Linux and don't know what information is required.  I bought a laptop on Amazon (ASUS X551MAV-EB01-B) pre-installed with Windows 8.1 64-bit I downloaded the proper Lubuntu .iso file for my system (Lubuntu 14.04.1 amd64) and put it on my flash drive (via UNetBootin) I went to Disk Management, and shrunk the C:/ drive down 32Gb so that 32Gb will be free for Lubuntu I used my flash drive (32Gb Sandisk Cruzer) as a LiveUSB for Lubuntu 14.04.1 I went through the install process. It didn't recognize Windows 8.1 so I had to do the "Something Else" option. I highlighted the free space, and pressed the + button I created a 10,000mb ext4 partition and mount point is / (is now dev/sda7) I created a 4,000mb swap area partition (is now dev/sda8) I created an ext4 partition using the rest of the free space and the mount point is /home (is now dev/sda9) I selected dev/sda7 to install Lubuntu and selected dev/sda7 for the bootloader installation It installed just fine, booted up just fine, and I'm happy to know the GRUB menu works.


In Return of the Jedi, Luke tells Leia, "The Force is strong in my family. My father has it. I have it... My sister has it."  This implies that Force sensitivity is a hereditary trait.  In The Phantom Menace, upon realizing that young Anakin is strongly force-sensitive, the first question Qui-Gon asks his mother is who the father is, which implies that Force sensitivity is a hereditary trait and the Jedi know it.  In Attack of the Clones, we learn that it is contrary to Jedi philosophy for Jedi to fall in love and marry.  This idea is taken even further in Revenge of the Sith, when Padme expresses worry that if the Council finds out Anakin has fathered a child with her, he would be expelled from the Jedi Order.  If Jedi are officially forbidden to marry and have children, and the Order knows that Force-sensitivity is a hereditary trait, this is functionally equivalent to a selective breeding policy to cull Force-sensitivity from the populace, and yet we see plenty of Younglings in the Jedi Temple in the prequel trilogy movies.  If the Jedi are actively not having kids, where do all the little Jedi come from?

I can't seem to find a satisfactory answer to this anywhere on the web. While  poses a related question, I don't think it sufficiently answers mine...  During the opening chapters of Jedi Search, Luke addresses the new Senate on the need to find new Jedi talent, or Force sensitive individuals. During this proposal, he cites that the most fruitful leads of Jedi potential are in the descendants of Jedi Knights: as Force sensitivity is hereditary. The book even discusses the notion that Leia should be comparatively well attuned to the Force, due to her being the child of Anakin Skywalker.  I understand that the concept of the Jedi as a totally celibate and monastic order was something that was retconned into the lore after Episode II: Attack of the Clones, and that there are examples of entire nuclear Jedi families exist (such as Andur Sunrider and Plo Koon)...  But if Force-manipulative ability is passed down genetically (as a potentially mutative property of their genetic makeup), why would the Jedi order be so numerous if they practice Chastity?  Even if procreation is not expressly forbidden (as in the pre-retcon Expanded Universe): why would Jedi need special permission to produce more Jedi potential children?  How are more Jedi created, if not through procreation? Has their profusion been deliberately retarded, and if so why? is there another explanation for their (pre-empirical) plenitude?


Reason is i have configured my official account in Evolution last day and and it stuckedup, then i tried to reconfigure its not working even the removed account is showing SEND& RECV  Pls help ma friends

I have not used Evolution for long time now and I would like to reset all the settings and start from scratch. How would I be able to do this?


When I look at  I see “26 Suggestions”:    When I look at the detail of any suggestion, and click on More, I get Editor Stats which says “Bill Woodger had 16 edit suggestions approved, and 11 edit suggestions rejected”:    The profile appears to be counting one less suggested edit than the sum of approved and rejected suggested edits. Why is the count different? In looking around, I noticed that suggestions on deleted posts are not removed. Might it be a deleted user? Or something else?  As can be seen from @animuson's Answer, I misunderstood the post I referred to (link in the comments). Although the Suggested Edit itself is not deleted, it is removed from my (or whoever's) list of Suggestions.

I think I found a bug on Stack Overflow, would like to have feedback if it is, so you can eventually fix it!  If I go on my personal profile in SO on the activity tab and select the suggestion button (in order to see all edits I have suggested) I see 19 entries:    However, if I select one of the suggested edits and follow the link I see in my Editor Stats that I actually have 20 edit suggestions, and so it looks as if one went lost.    What's going on?  Which stat is correct? (Don't know if it's of any use but I remember doing 20...)  EDIT:  new proof of bug added, if I go on my review section in the lateral tab I'll see this recapitulation, which goes against editor stats


When I run sudo apt install npm  I get: Media change: please insert the disc labeled                                     'Ubuntu 20.04.1 LTS _Focal Fossa_ - Release amd64 (20200731)' in the drive '/cdrom/' and press [Enter]

When I type sudo apt-get install rails I get the message:  media change: please insert the disc labeled 'Ubuntu 12.04.3 LTS _Precise Pangolin_ - Release amd64 (20130820.1) in the drive '/media/cdrom/' and press enter   I am new to Linux and I have the installation CD in the drive, but I have no idea what disc it is asking for and I'm not sure what /media/cdrom/ means. All I have is the installation CD and it is in the only optical drive I have.


I'm in the process of learning JavaScript and have come across an issue I don't understand.  I have a simple webpage I'm using for testing, and here I'm trying to use for-in loops to change the background colour of all h1 elements to red, and all h2 elements to blue.  var h1 = document.getElementsByTagName("h1"); var h2 = document.getElementsByTagName("h2");  for (i in h1) {     h1[i].style.backgroundColor = "red"; }  for (i in h2) {     h2[i].style.backgroundColor = "blue"; }   When I run this code, the background of all h1 elements turn red as intended. However, none of the h2 elements change at all.  I get an error in the console that says:           TypeError: h1[i].style is undefinedI don't understand this however as the code it's referencing seems to run just fine.  If I comment out h1[i].style.backgroundColor = "red"; and refresh the page, all of the h2 elements are changed to blue.  I then get an error in the console similar to the first one: TypeError: h2[i].style is undefined  Does anybody know what's going on any why my code isn't running both these loops? It looks like it runs fine until the end of the first loop, then errors out and stops running so doesn't run the second loop.  Thanks in advance!

I've been told not to use for...in with arrays in JavaScript. Why not?


I want to buy a FujiFilm X-series camera, and wonder if I will be able to use my Nikon (Nikkor) lens with it.

I've got some lenses of brand X, but I've just got a new camera of brand Y. How can I tell if it's possible to use my lenses on my camera? I accept that I may lose a lot of automatic functionality like autofocus, aperture control and metering when using an adapter to connect the two.


I’m trying to prove the following result:     Given $3$ pairwise disjoint lines $L_1$,$L_2$ and $L_3$ in $\mathbb{P}^3(k)$, we can find a change of coordinates such that $L_1=V(Z,T)$, $L_2=V(X,Y)$ and $L_3=V(X-Z,Y-T)$.   I’ve started by writing $$L_i=\{U(x_i:y_i:z_i:t_i)+V(x_i’:y_i’:z_i’:t_i’)\mid U,V\in k\}$$ Then since $L_1$ and $L_2$ are disjoint we can’t find any $A,B,C,D\in k$ (not all $0$) such that $$\begin{align*}&A(x_1,y_1,z_1,t_1)+B(x_1’,y_1’,z_1’,t_1’)\\&+C(x_2,y_2,z_2,t_2)+D(x_2’,y_2’,z_2’,t_2’)=0\end{align*}$$ and so these vectors are linearly independent. Then we can invert the matrix $$\begin{pmatrix}x_1 & x_1’ & x_2 & x_2’\\ y_1 & y_1’ & y_2 & y_2’\\ z_1 & z_1’ & z_2 & z_2’\\ t_1 & t_1’ & t_2 & t_2’\\\end{pmatrix}$$ to give a change of coordinates mapping $L_1$ to $V(Z,T)$ and $L_2$ to $V(X,Y)$.  But I can’t see why in general we should be able to map $L_3$ to $V(X-Z,Y-T)$, since a linear map is determined by its action on a basis. Any help would be much appreciated.

Consider three skew (non-intersecting) lines $L,M,N$ in $\mathbb{P}^3$. Each line is given by two equations of the form $\alpha_{i,j}^\top z = 0, \, i=1,2,3, j = 1,2$, where $z=(z_0,z_1,z_2,z_3)$ are the homogeneous coordinates of $\mathbb{P}^3$ and $\alpha_{i,j} \in \mathbb{P}^3$.  What i want is to show that up to projective equivalence the equations for the three lines can be written as (this is possible according to the hint of exercise 2.12 in Harris, Algebraic Geometry - a first course)  $L: \, z_0=z_1=0 \\ M: \, z_2=z_3 = 0 \\ N: \, z_0=z_3, \, z_1=z_2.$  Since say $L, M$ are non-intersecting, this implies that $\alpha_{i,j}$ for every $i=1,2, j=1,2$ are in general position. So they are projectively equivalent to $(1,0,0,0), (0,1,0,0),(0,0,1,0),(0,0,0,1)$. This gives us  the description that we want for $L$ and $M$. But how about $N$?  Note here that the most general result that we have is projective equivalence between two sets of 5 points in general position. In the context of the present question, i am concerned about two things:  1) The fact that the lines $L,M,N$ are skew does not imply in general that  every group of 5 points among the $\alpha_{i,j}$ will be in general position.   2) The $\alpha_{i,j}$ are six!  Question: What am i missing here? How can the above two issues be addressed?


I am looking for a way to generate all combinations of items in a given list with an output of a given count. The inputs will be the list and the number of items in each returned combination. For example:  list = [a, b, c, d] number of items in output: 2   returns:  [(a, b), (a, c), (a, d), (b, c), (b, d), (c, d)]   The same list with number of items in output: 3  returns:  [(a, b, c), (a, b, d), (a, c, d), (b, c, d)]   note that (a, b) == (b, a) etc.  Thanks!

I have a list with 15 numbers in, and I need to write some code that produces all 32,768 combinations of those numbers.   I've found  (by Googling) that apparently does what I'm looking for, but I found the code fairly opaque and am wary of using it. Plus I have a feeling there must be a more elegant solution.  The only thing that occurs to me would be to just loop through the decimal integers 1–32768 and convert those to binary, and use the binary representation as a filter to pick out the appropriate numbers.   Does anyone know of a better way? Using map(), maybe?


When traveling it is a great experience to talk to locals and make friends. Sometimes also emergencies and unforeseen situations require one to ask for help and seek assistance.  In most cases of course, the official language of a country is the safest bet if one wants to be sure to be well-prepared for any situation and make the most of one's stay in a country.  On the other hand, it is unreasonable to assume tourists would learn the official language of each country they visit. Language acquisition takes a large amount of motivation, time and resources, which a holiday trip in general doesn't allow.  From a general point of view, what (approx.) 3 languages are the most useful to learn to communicate in the most places in the world?    Some of my thoughts on this:   English is the most obvious choice, since it has the most L2 speakers and is spread over most of the world, i.e. it is not concentrated in one country. Mandarin or Cantonese might have the most L1 speakers, but the use is quite limited to China itself. Unless the trip goes to China, it might not make much sense to spend the time to learn those languages. German for example might be useful, since it is spoken in several countries. However, most German speakers (or Europeans, for that matter), have a good knowledge of foreign languages and are likely to know English or French. Therefore, German is probably also not necessary to learn. Russian is a language I could see make the list; it widely spoken in many countries, especially in places where English is not prominent and the official language has few speakers (Estonian, Bulgarian, Tajik, etc.)

This follows on from a travel conversation a group of us had in a hostel in London.  Assuming I am travelling randomly between countries and continents, which two languages in addition to English would provide the most usefulness in any given country?  I suspect Spanish (North America, South America) and French (Europe, Africa) but with the base understanding between French and Spanish maybe the time would be best spent learning another language?  This question is a real puzzler since the following constraints apply   Length of time required to be "functional" in the language (cost-time trade off) Chance of reaching proficiency within any meaningful timeframe (Mandarin) Regional dialects destroying proficiency (Arabic) Easier Secondary languages underpinning the society (Arabic versus French argument) Similarity of Language families (Romance) leading to wasted effort (Italian v French) Utility of the Language (German versus English when English is understood) Enjoyment is a minor consideration   Happy to consider any other thoughts but it is a really interesting topic for consideration if you are linguistically minded.


I am trying to hook some glibc functions that has works with file names. Basically I need to modify the filename a bit, then pass it along with other arguments to the original glibc functions.   The code looks like this:  FILE *fopen(const char *filename, const char *modes) {   filename = modify(filename); // assuming we don't need to free the new filename pointer for now   using FuncT = FILE*(*) (const char *, const char *);   static FuncT originalFunc = (FuncT)dlsym(RTLD_NEXT, "fopen");   return originalFunc(filename, modes); }   This works fine for most cases, but when it comes to variadic arguments for function like int execl(const char *path, const char *arg, ...), How can I do it properly?

In C, is it possible to forward the invocation of a variadic function? As in,  int my_printf(char *fmt, ...) {     fprintf(stderr, "Calling printf with fmt %s", fmt);     return SOMEHOW_INVOKE_LIBC_PRINTF; }   Forwarding the invocation in the manner above obviously isn't strictly necessary in this case (since you could log invocations in other ways, or use vfprintf), but the codebase I'm working on requires the wrapper to do some actual work, and doesn't have (and can't have added) a helper function akin to vfprintf.  [Update: there seems to be some confusion based on the answers that have been supplied so far. To phrase the question another way: in general, can you wrap some arbitrary variadic function without modifying that function's definition.]


Sometime in the late 70'ties or 80'ties I read this novel. It's about a man traveling to a planet where the human colony has a lot of trouble with the indigenous life. The man from the planet accompanying him is very big, muscular, with faster reflexes than ordinary men. This is an adaptation to the conditions on the planet they are traveling to. The conditions on the planet are getting worse all the time.   At the end of the book it is revealed that the local life is reacting telepathically to human aggression, so the situation is becoming worse as the human colonists are becoming more aggressive to save their lives. As the humans realise this they solve the problem by becoming less aggressive.  Can anyone help me find out which novel this is?

I listened to this on audiobook and it was great.  The premise was a human ends up travelling to an alien planet. The aliens have a perimeter to their 'base' that is under constant attack from the planet's animals. It is revealed towards the end that there is some sort of signal being transmitted that is making all the animals and plant life attack a certain point on the planet (where the aliens are).   Other major plot points I remember: The human traveller falls in love with an alien. The aliens have a sort of virtual training environment that simulates life outside the perimeter, where plants attack you etc. There is a secondary alien group that the human ends up with, and although they are rivals to other group, they have a trade set up.   Any help much appreciated! Thanks.


I have written these two classes. First, is the GUI I created and second is the JDBC connector between Java and SQL. I want to add an update statement in my code but no matter what I have tried I get the same error.  This is for a university project. I have already tried Prepared Statement instead of Statement, I have test this query:  String query = "UPDATE user SET name = 'TEST' WHERE username = 'cleogeo'";  instead of the one in the code and I know connection and getters and setters are working properly since the rest of the program executes fine.  CandidateUI Class (GUI): Here I create "edit and save mode" in the GUI to make it easier for the user to change his profile settings.   private void EditAndSaveActionPerformed(java.awt.event.ActionEvent evt) {                                                     counter++;         if(counter%2 == 1){             changePassword.setEditable(true);             changeName.setEditable(true);             changeSurname.setEditable(true);             changeEmail.setEditable(true);             changeBio.setEditable(true);             EditAndSave.setText("Save");         } else {             changePassword.setEditable(false);             changeName.setEditable(false);             changeSurname.setEditable(false);             changeEmail.setEditable(false);             changeBio.setEditable(false);             EditAndSave.setText("Edit");             newPassword = changePassword.getText();             newName = changeName.getText();             newSurname = changeSurname.getText();             newEmail = changeEmail.getText();             newBio = changeBio.getText();             iCRUDImpl.getCandidateUI(changeUsername.getText());         }     }   Then I create getters and setters for every "new" variable.  ICRUDImpl Class (JDBC):  public CandidateUI getCandidateUI(String username) {         try{             CandidateUI candidateUI = new CandidateUI();             Statement statement = connection.createStatement();             String query = "UPDATE user SET password = '" + candidateUI.getNewPassword() + "', name = '" + candidateUI.getNewName() + "', surname = '" + candidateUI.getNewSurname() + "', email = '" + candidateUI.getNewEmail() + "' WHERE username = '" + username + "';UPDATE candidate SET bio = '" + candidateUI.getNewBio() + "'";             statement.executeUpdate(query);             return candidateUI;         } catch (SQLException e) {             return null;         }     }   The error I get is a java.lang.NullPointerException in line  Statement statement = connection.createStatement();   of JDBC.  Here is also my Connection Method:  public void openConnection() {         try {             Class.forName("com.mysql.jdbc.Driver");             this.connection = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/erecruit", "root", "");             System.out.println("Connection established successfully with the database server.");         } catch (ClassNotFoundException | SQLException e) {             System.err.println("Error: " + e.getMessage());         }     }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


What would be the easiest way to solve the following set of equations:$$ x +  y^2 = 7 $$$$ x^2 + y = 11$$  I've been trying substitution method but end up in a $4$th degree bi-quadratic equation. Thanks for your time!  EDIT: Final equation: $y^4 - 14y^2 + y + 38 = 0$. I'm only concerned about the real solutions. Is it possible to write it as a product of two quadratic equations?

Possible Duplicate:          During the flight from Moscow to Yerevan my neighbor gave me the following problem:  Solve the system:  $$\left\{\begin{array}{c}x^2+y=7 \\ y^2+x=11. \end{array}\right.$$  It is easy to find 1 of the 4 solutions. Is there a beautiful way to find the other three?


I have the following two xml links, each of which I want to use as the file parameter to :  table1 = 'https://www.sec.gov/Archives/edgar/data/1103804/000110380417000040/xslForm13F_X01/Form13fInfoTable.xml' table2 = 'https://www.sec.gov/Archives/edgar/data/1103804/000110380417000040/Form13fInfoTable.xml'   What I have tried:   Using raw strings (r'https:// ...) Excluding https:// in each of the path names (to get rid of the colon on a Windows system) Using 'r' within open(), which should be unnecessary anyway because it is the default   There are a number of similar SO questions, none of which offer solutions that get rid of this error.  Although the following is seemingly innocuous I cannot get past the error.  For instance,  d = open(table1, 'r') --------------------------------------------------------------------------- FileNotFoundError                         Traceback (most recent call last) <ipython-input-110-07d32326a11e> in <module>() ----> 1 d = open(table1, 'r')  FileNotFoundError: [Errno 2] No such file or directory: 'www.sec.gov/Archives/edgar/data/1103804/000110380417000040/xslForm13F_X01/Form13fInfoTable.xml'

I have a small utility that I use to download an MP3 file from a website on a schedule and then builds/updates a podcast XML file which I've added to iTunes.  The text processing that creates/updates the XML file is written in Python. However, I use wget inside a Windows .bat file to download the actual MP3 file. I would prefer to have the entire utility written in Python.  I struggled to find a way to actually download the file in Python, thus why I resorted to using wget.  So, how do I download the file using Python?


I have this equation:     $$f(x)=\tan(x)$$   I found  the vertical asymptotes to be:     $$x=\frac{\pi}{2}k$$   What is the proper notation for that k is equal to every odd number integer(negative,positive, and zero)?  $$k\in\mathbb{Z}$$ is for every integer, but is there such a symbol for every odd number integer?   Natural numbers are positive, and sometimes zero counting numbers, my question is about integers not natural numbers.

Obviously the set of naturals is denoted $\mathbb{N}$, but is there a symbol for the set of odd naturals? Would $2\mathbb{N}+1$ (or $2\mathbb{N}-1$) be a standard notation?


first of all I'm a newbie with ubunutu servers or generell with linux. So I'll be glad if someone can explain it very simple. ^^'  My Server is a Ubuntu 16.04 LTS Server 64bit + Plesk Onyx from Strato (German Hoster).   I've the problem that my FTP webspace is on my /var directory and I've just 70GB on this /var of 2*240GB SSD.  Unfortunately the server was preset with the webinterface installation (however I've a dedicated server).  My /home on the one hard disk of 240GB has 118GB and I'm still using 500MB ... Can I shrink this /home for example to 25GB and give the 'free space' my /var? (If it's possible without shutting down the server?)  Hopefully I've explained my problem well enough. I hope anyone can give me accurate instructions to do this task. :|

How can I increase the size of the root partition of a system at runtime?   I have a partition that is not allocated after the root partition (which is also ext4), how can I add that unallocated space to the space allocated to the root partition without having to shutdown the server?


I am currently trying to light up a staircase at my house. I bought two 5M reels of WS2812b 5V LED strips on AliExpress and some solderless connectors... I am planning on putting about 40cm on each step, which would in total be exactly 6 meters of LEDs.  One thing I am struggling with is choosing a correct power supply for my needs. The seller says that the strip needs 18 watts per meter.. Which would make 18*6=108W in total. Do I need a power supply that has exactly 108w or can it be more (or less)??  Also I am connecting each step in parallel with the next one. Does this change anything?  And If I choose a power supply and then use the LEDs on half power (or less), does that matter? Thanks in advance!  PS. My wiring will be the same as on this image:

After always being interested in learning more about electronics, I figured LED-strips would be a great start.  I'd like to power a 4 meter WS2812B-LED-strip (60 LEDs/m). These run on 5V and draw about 60mA per LED. That's 14.5A, or 75W. However, I've yet to find any power supplies for these figures, only imported industrial ones - which feels a bit scary with my limited knowledge.  I've understand that powering it through the Arduino is a bad idea, but what's the simplest and cheapest solution for powering it? I do have a bunch of old supplies for laptops and whatnot lying around.


For some reason, a part of the render is invisible.  It might be the material (i didnt make it), but i don't know how to fix that    The paint was taken from this but the color was changed a bit    this is the problematic part of the object.

If you render, the roof of the car becomes invisible.  How do I fix this?


At several points, ghosts are shown to be under the ministry’s control. But ghosts seem to care little about the law, and I doubt peeves would do it out of obedience. How does the ministry control ghosts? I am not asking how ghosts are punished, I am asking why ghosts are so easily controlled and ordered about, why don’t they refuse or run of? I repeat my earlier statement.

I started thinking about this question when I saw  to  about whether Muggles can see ghosts. The answer says that they can, but typically (ghosts) do not reveal themselves; partly because they want to be left alone, but also partly because they fear "punishment" by the Ministry.  My question is, what "punishment" could you give a ghost, or, more accurately, how do you make the ghost want to suffer the punishment rather than whatever else you could do to it? For example, we humans go to jail or do community service because if we don't, the other things the [insert location here] government could do to us would hurt more.  As an example, the answer I referenced says the Ministry made Moaning Myrtle go back to her bathroom, but what I am asking is what could it do to her that would make going back to her bathroom preferable? Ghosts are already dead, so you can't kill them again (or can you?), and they are incorporeal, though probably not completely intangible.  We know from Chamber of Secrets, the book, that ghosts can taste and presumably feel, though barely, as a ghost at Nearly Headless Nick's Deathday Party (which is sadly not in the movie) has to float his head through some type of rotten, spicy food to taste any flavor at all.   However, this doesn't seem to be able to extend very far. Yes, the ghost feels things, so one could perhaps put the ghost in an electric torture chamber or something similar if he/she does not comply, but would they really want to do that for every Peeves-like manchild poltergeist? Is there perhaps a Ghostbuster-style ghost container, able to vacuum up ghosts and put them in solitary confinement, or a Danny Phantom-like "ghost world" (probably separate from the Veil) where they could store unruly ghosts?  One thing I know could make a ghost hurt would be to isolate the ghost from other people/ghosts. Humans are social creatures, and I assume ghosts are the same way, even considering how . However, again, this could only go so far, and some humans and ghosts would love nothing more than to be left alone, so exile would be like a reward for killing innocent humans and causing too much ruckus, rather than a punishment.


I have an unlocked Samsung Galaxy S2. I bought it from Bangladesh. It has been working well with any Bangladeshi GSM SIM card. I just arrived in USA. Is it possible to get a Verizon GSM SIM card for my phone?

Sometimes it's desirable to use a device on a carrier that does not officially sell it. Often this is due to regional differences and travel (for example, using a US phone in Europe) but also because some carriers simply do not offer phones that other carriers do.  How can I determine if it's possible to use my phone on a different carrier, and which carriers it is compatible with?    This community wiki is intended to be a canonical answer to a common question. If you feel that improvements could be made then please edit the post(s).


Is the operator $T$ defined by $(Tx)(t)=tx(t)$ $(0<t<1)$ a compact operator in $L^2(0,1)$ ? We have know the compact set in $C[a,b]$ by Arzelà–Ascoli theorem, but I don’t know how to show the compactness in $L^p$ space.

Suppose we have an bounded linear operator A that operates from $L^2([a,b]) \mapsto L^2([a,b])$.  Now suppose that $A(f)(t) = tf(t)$.    Is A compact?  Edit: I know $A = A^*$ but I'm not really sure how to start on this.  It's not homework, just summer fun :D


I have define a new float "scheme" and want to reference it as figure or table floats do. How could I define a new label type for the "scheme" float to reference it in the article? I have tried to use fig or tab labels, but they do not work. See the picture.   Tex code:  \documentclass[a4paper, 11pt]{article} \usepackage{caption}           % Use table caption \usepackage{chemfig}           % Use chemical strutures \usepackage{hyperref}  \DeclareCaptionType[fileext=ext, name=Scheme, placement=tbph!]{scheme} \captionsetup[scheme]{labelsep=period, font={small, bf}, skip=8pt}  \begin{document} This is a chemical reaction:  \begin{scheme}[h!] \renewcommand*{\figurename}{scheme} \centering \schemestart \chemfig{*6(-=-=-=)} \+ \chemfig{H_2} \arrow \chemfig{*6(-(-H)=-=(-H)-=)} \schemestop \label{sh1}  % define a new label type for scheme float \caption{Reaction of Benzene Synthesis} \end{scheme}  A relatively simple, as shown in Scheme~\ref{sh1}, is neutralized by the solution contained within it to form a charged double layer, which under the influence of an applied electric field leads to the electroosmotic mobilization of the solution.  \end{document}

I'm trying to understand why I cannot effectively reference figures or equations that I have defined with labels.  For example:  \begin{figure}   \label{fig:area_Treasuries}   \caption{Treasuries as a portion of total financial flows.}   \centering   \includegraphics[width=0.75\textwidth]{graphs/Area_Treasuries.png} \end{figure}  \paragraph{} Figure~\ref{fig:area_Treasuries} presents Treasuries (both flowing into and out of the United States) as a share of total financial flows.  From 1985 to 2010, Treasuries account for, on average, 53.2\% of total financial flows.   With the above code, I get this warning:      LaTeX Warning: Reference `fig:area_Treasuries' on page 37 undefined on   input line 477.   The result is "Figure ?? presents Treasuries..."  Why is this happening?  Related, I don't understand why I can't reference, say, an equation before (I mean physically above in the text) the actual equation.  Isn't this what compiling multiple times and cross references is supposed to take care of?


I understand 2D vectors in terms of displacement. For example, Bob moves 3m to the east and 4m to the north, the total change in position (displacement) equals 5m to the north east.  But I don't understand how 2D velocity vectors can be broken down into their horizontal and vertical components.

Last year, I took physics and over the summer I have started to wonder about why many phenomena work the way they do (such as why is $\mathrm{KE} =\frac{1}{2}mv^2$, etc.). I have found answers to all of my questions, except for this one:  Why are we allowed to use trigonometry to get vector components? I understand that if we draw a right triangle, then we can express the adjacent side with $\text{length of hypotenus} \times \cos(\theta)$. But why does this work with velocity and with forces? I have tried to reason through this many times, but I am not able to figure out why we are able to do this. Any ideas?   BTW: My attempts for reasoning through velocity were as follows: If we have a ball moving in two dimensions, and we are given that the ball has $\sqrt{3}$ the speed in the x-direction than the y-direction, then we can conclude that the ball will move in a 30-degree angle. I am not sure how to apply this to forces or acceleration though. For example, why is it that in the case of a ball spinning horizontally while attached to a string, that the y component of the strings tension gets smaller as the centripetal force increases? I can see how we can prove this by using trigonometry, but why does this trig work in the first place?


Prove that   $$ \lim_{n \to \infty}\int_0^{n^2} n\sin(x/n)e^{-x^2} dx = 1/2.$$   I've tried all of the techniques learned in the course so far and none of them seem to work, so if anyone could help me with this it would be much appreciated. Thanks!

I am trying to compute this integral/limit, I don't feel like I have any good insight...   $$\lim_{n \to \infty} \int_0^{n^2} e^{-x^2}n\sin\frac{x}{n} \, dx.$$  I have tried to make a change of variable to get rid of the $n^2$, I changed to $X=\frac{x}{n^2}$ but got something even worse, I've tried to reach a situation where I could use a convergence theorem for Lebesgue Integrals,... I'm not sure I'm even on the right track!  Could you give me a hint on how to start this?  Thank you very much!


When i tried to edit .bashrc file I am getting the above error how to solve this. when i gave  $ echo $PATH /home/vijay/usr/bin:PATH:/bin   is displayed Steps in detail would help

I want to add a directory to search my search path. I know I have to modify the PATH environment variable. However, I want the change to be permanent, so that it is always in effect, for every Terminal (bash) window I open.  There is an overload of confusing and possibly conflicting information in   I am using Ubuntu 10.04. Suppose I want to add /usr/local/foo to my PATH. Which file (.bashrc, .profile, .bash_login, etc...) should I modify and what should the new line(s) look like?


I am working on my Master's thesis and the citations are required to appear in the footnotes of the page where they are cited so I am using \footcite whenever I need to reference something in my bibliography. However,, by default, this means that after every chapter, the citations counter is reset such that the citations of each chapter start back at 1. However, the citations at the end of the bibliography don't! For example, the first citation of the 5th chapter appears as 1 in the footnote, but it is actually the 20th citation of the whole document. How can I make the footnote to show that it is refencing 20? This is how I am using the bibatex package: \usepackage[citestyle=verbose,bibstyle=numeric,sorting=none,defernumbers,backend=biber]{biblatex}

I would like footnote numbering to continue over pages and chapters. In my document it's reset every chapter. I'm using the report documentclass.


When I try to copy an 8 GB video file (.mov) from the Files -> Downloads directory to a Sandisk jumpdrive with 31 GB of free space on it (after emptying all trash), the copy stops at about 4 GB and eventually times out with the error message      Error splicing file: File too large.   Not sure if this a driver problem or something else. Any suggested solutions would be appreciated.

I am trying to copy a 6GB file to a USB flash drive but it won't copy.


A version of the axiom of choice is:  Every set $S$ has a choice function $f$, where $f$ is a function from the set of all nonempty subsets of $S$ to $S$, s.t. $f(A)\in  A$ for nonempty $A$.  I'm trying to prove that this is equivalent to:  The product of a family of nonempty sets indexed by a nonempty set is nonempty.  But I'm not sure if I'm correct: Suppose we have a choice function on every set, then for every such product, let $S$ be the set of all nonempty subsets of the union of all indexed sets (which I've assumed to be a set, some shaky ground here) then let $f$ be the choice function on this union, then the product has at least one element which is $(f(A_i),,,,)$ where $i$ are the indices.

I'd like to know if my proof is correct or incorrect in the following.  Given definition of Axiom of Choice (AoC): The direct product of a family of non-empty sets indexed by a non-empty set is non-empty.  Show that the Axiom of Choice is equivalent to the statement that every set has a choice function.  (Choice Function => AoC):   Suppose every set has a choice function.  Let S be a set, and fix a natural number n.   Let $$ I = \{1,2,....,n\}  $$ and let $\mathbf A$ be a family of non-empty subsets of S sets indexed over I.  $$ \mathbf A = \{A_1, A_2, ... , A_n\} $$  The task is to show that the direct product over sets in $\mathbf{A}$ is non-empty. This will be shown if an element of this set can be produced.   Let $$ D = A_1 \times A_2 \times ... \times A_n $$  By supposition, this set has a choice function $f$ defined over non-empty subsets $X$ of $D$ with the following:  $f: X \to D$ such that $f(X)∈X$ for all subsets $X$.  So, $f(X) ∈ X$ $\Rightarrow$ $f(X) ∈ D$.   So, $D$ is non-empty.  (Show AoC => Choice Function):  Suppose the Axiom of Choice, let S be a set, and fix a natural number n.  Let  $$ I = \{1,2,....,n\}  $$ and let   $$ \mathbf{A} = \{A_1,A_2,....,A_n \}  $$  be a family of non-empty subsets of S indexed over I.  Let $$ D = A_1 \times A_2 \times ... \times A_n $$  By the Axiom of choice, $D$ is non-empty.  Let $y ∈ D$ and define a function $f: D \to D$ by $f(x) = y$ for all elements $x ∈ D$.  (So, every element of D is mapped to this fixed element $y$.)  So, $f(x)∈D$ for all $x∈ D$.  In other words, $f$ defines a choice function on $D$.   So, assuming the Axiom of Choice implies that $S$ has a choice function defined on its non-empty subsets.


G=(v,e) is a simple planar graph with |v|>10 vertices. I need to prove that G#=(V,E#)-the complement of G- is not a plannar graph.  I tried to use Euler's formuala, but it didnt went well.

It is an exercise on a book again. If a simple graph $G$ has 11 or more vertices,then either G or its complement  $\overline { G } $ is not planar.  How to begin with this? Induction?  Thanks for your help!


If $x,y,z$ are positive real numbers, prove that: $\left(x+y+z\right)^2\left(yz+xz+xy\right)^2\le 3\left(y^2 + yz + z^2\right)\left(x^2 + xz + z^2\right)\left(x^2 + xy + y^2\right)$.  I have been stuck in it. It is an Indian Olympiad problem. Can you guys help me out, please?

This is Problem 6 of the 2007 Indian National Math Olympiad (INMO).  If $x, y, z$ are positive real numbers, prove that $(x+y+z)^2(yz+zx+xy)^2 \leq 3(y^2+yz+z^2)(z^2+zx+x^2)(x^2+xy+y^2).$  My best idea was to expand this and simplify. Although that doesn't look very feasible. Another idea is to see that $x^2+y^2+xy \geq x^2+y^2$. Then we just have to show that $(x+y+z)^2(yz+zx+xy)^2 \leq 3(x^2+y^2)(x^2+z^2)(y^2+z^2)$ if that is even true.


I'm trying to parse command line options read from an already started process. The raw string looks like that -skipIntro -noSplash -cpuCount=7 -exThreads=7 -enableHT -malloc=tbb4malloc_bi_x64 -hugePages -maxmem=4096 -maxvram=2048 -world=empty -showScriptErrors -mod=  Single parameters can have four different formats     Parameter without value: -skipIntro Escaped parameter without value: "-skipIntro" Parameter with value: -mod=foo Escaped parameter with value: "-mod=foo" or "-mod=b ar"   Escaped parameters could include white spaces. I want to split all parameters into an array of strings. The splitted parameters should include the prefix - respectively "-.  My regex looks like this: \s*[\"]*?- which is working fine. However this also removes the prefix mentioned above. How can I include the prefix into the separated params array?

I have a single string that contains the command-line parameters to be passed to another executable and I need to extract the string[] containing the individual parameters in the same way that C# would if the commands had been specified on the command-line. The string[] will be used when executing another assemblies entry-point via reflection.  Is there a standard function for this? Or is there a preferred method (regex?) for splitting the parameters correctly? It must handle '"' delimited strings that may contain spaces correctly, so I can't just split on ' '.  Example string:  string parameterString = @"/src:""C:\tmp\Some Folder\Sub Folder"" /users:""abcdefg@hijkl.com"" tasks:""SomeTask,Some Other Task"" -someParam foo";   Example result:  string[] parameterArray = new string[] {    @"/src:C:\tmp\Some Folder\Sub Folder",   @"/users:abcdefg@hijkl.com",   @"tasks:SomeTask,Some Other Task",   @"-someParam",   @"foo" };   I do not need a command-line parsing library, just a way to get the String[] that should be generated.  Update: I had to change the expected result to match what is actually generated by C# (removed the extra "'s in the split strings)


Can you install a 2x4 wall that is 13' long on top of a travertine tile floor? Or do I need to cut the tile and mount the bottom stud right to the cement? This will not be a load bearing wall.

Looking at moving my laundry upstairs, and the right answer is to combine two adjacent closets to get the width and move one of their walls a foot or two into the kitchen to get the depth.  The kitchen floor is 10-inch-square tiles. It would be sort of nice if that continued on into the laundry closet. I do have a full bundle of spare tiles in the basement.   Question: Could/should I plan on the new wall coming in on top of the existing tiles (presumably having to drill to secure the footer without shattering them), or should I plan on removing the ones under the footer and fitting cut pieces back in afterward?


I'm using formidable plugin to upload an image to node server, after upload is done, it returns an iframe with the corresponding message of success and its path. I would like to retrieve this message to a string variable at client side (browser).  The above object is taken using var tempPath=document.getElementById('imho_id'); I've tried document.getElementById('imho_id').innerHTML; but with no success. My confusion here is the #document part and the access to  style object, i appreciate if someone could help and also briefly explain the logic of accessing document or #document. Thank you in advance!

I would like to manipulate the HTML inside an iframe using jQuery.  I thought I'd be able to do this by setting the context of the jQuery function to be the document of the iframe, something like:  $(function(){ //document ready     $('some selector', frames['nameOfMyIframe'].document).doStuff() });   However this doesn't seem to work. A bit of inspection shows me that the variables in frames['nameOfMyIframe'] are undefined unless I wait a while for the iframe to load. However, when the iframe loads the variables are not accessible (I get permission denied-type errors).  Does anyone know of a work-around to this?


Hi I would like to have a class:  class Matrix <T>     where T : // I don't know what to write here {     T[][] elements; }   I would like T to be addable and multiplyable by + and * operators

Can anyone tell me if there is a way with generics to limit a generic type argument T to only:   Int16 Int32 Int64 UInt16 UInt32 UInt64   I'm aware of the where keyword, but can't find an interface for only these types,  Something like:  static bool IntegerFunction<T>(T value) where T : INumeric


When writing Bash scripts, how can I obtain a value from the command-line when provided as part of option flags in the command line?  For example in the following:  ./script --value=myText --otherValue=100   How could I store the myText and 100 values in the variables $text and $num?

Say, I have a script that gets called with this line: ./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile  or this one: ./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile   What's the accepted way of parsing this such that in each case (or some combination of the two) $v, $f, and  $d will all be set to true and $outFile will be equal to /fizz/someOtherFile?


I have uninstalled and reinstalled QGIS several times from the OSGeo4W application.  I have done this with no problem on several other times, but now I cannot get the tools to load.  Most of the help simply say to just use the OSGeo4W application and not to worry about anything else.  What do you do when the OSGeo4W application is not working.   Do I need to change the Windows environment variables manually?  I have never had to do this before.

I have recently installed QGIS 2.8.2 on my Windows 8.1 laptop with the stand alone .exe installer.  The processing toolbox is missing the GDAL/OGR, GRASS, QGIS algorithms, Saga and the Orfeo Toolbox from the processing toolbox which I have on my 2.8.2 installation on a Windows 7 machine using the same installer file.  I have checked the plugin options and all of them are set to activated.  Also the paths are set too and they were pointed at C:\Porgra~1\Wein\apps\"module folder"  I have tried changing it to what is recommended in Joseph's comment to the .qgis path under the users directory but with no change to what is shown  Has anyone else encountered this problem?


According to Dragon Ball Super's manga, Trunks is able to transform to SSJ2 which was used to defeat Dabura and Babidi. When he traveled to the past, he didn't know about Goku's SSJ3.  In the fight against Zamasu and Black, he transformed into a powerful Super Saiyan form, for a moment and could handle a battle with Zamasu, apparently this is not a stronger transformation like SSJGSSJ (Super Saiyan Blue).   Also this transformation has a similar Ki aura of a Super Saiyan Blue, but he keeps hair of a SSJ2. So, what transformation is this?

Some people say it is a False Super Saiyan God, other people say it is a Super Saiyan God 2, while another group of people say it is something different. Is there any official info on what it is exactly?


Unity was excellent at managing vertical space on the screen by rolling the top bars (the app title bar, its menu bar, and the system's status bar) into one, especially when the application's window was maximised. Gnome 3, at least by default as shipped with Ubuntu 17.10, doesn't quite measure up.   In some instances, like with gnome-terminal, there are three bars, two of which are completely unnecessary and feature the same information over and over. I marked redundant user@host with red boxes.    How can I recreate the space frugality Unity would display here?

Just moved from Unity to GNOME with the update to Ubuntu 17.10. There is a HUGE amount of wasted space at the top of the screen, when an application is open.  Evolution and Firefox both have four "bars" with 90% of each empty. Unity, to its credit was able to blend / mix these horizontal bars so there was only one / two.      Four is way too much. If this is GNOME I may carry on with Unity for the next six months.  Can anybody suggest a tweak/change/fix for this?


The famous example of acrobats shrinking their bodies to increase their rotation speed is well known. Where does the energy to increase the speed of their rotation comes from?

This may be a very basic question but I am not seeing how it works. Consider the standard example of an ice skate rotating about his/her center of mass and pulling in his/her arms. The torque is zero so we have conservation of angular momentum. This implies that $\omega$ increases to keep $I\omega$ constant, but then $K_{rot}=\frac{1}{2}I\omega^2$ doesn't stay constant, it increases. This implies that there is work done, but what force is doing this work?


i had installed windows 7(32 bit) and Ubuntu. It was working fine, but after that I installed Windows 8 (64 bit) instead of Windows 7. Now I'm unable to boot Ubuntu.  Please help me to open my previous Ubuntu and how I'll get my data which were inside Ubuntu.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


I am trying to study assignment in python I was confused by this.  >>> a=343434;b=343434 >>> a is b True >>> a=343434 >>> b=343434 >>> a is b False

Why does the following behave unexpectedly in Python?  >>> a = 256 >>> b = 256 >>> a is b True           # This is an expected result >>> a = 257 >>> b = 257 >>> a is b False          # What happened here? Why is this False? >>> 257 is 257 True           # Yet the literal numbers compare properly   I am using Python 2.5.2. Trying some different versions of Python, it appears that Python 2.3.3 shows the above behaviour between 99 and 100.  Based on the above, I can hypothesize that Python is internally implemented such that "small" integers are stored in a different way than larger integers and the is operator can tell the difference. Why the leaky abstraction? What is a better way of comparing two arbitrary objects to see whether they are the same when I don't know in advance whether they are numbers or not?


As a native English speaker, I find the phrase "The hammer need not to be large for..." sounds strange to my ears.  Instead, I prefer "The hammer need not be large for...".  But what is the rule that makes the former grammatically wrong?  Or, maybe I am in error, and indeed the former is technically correct...

The header of  states:     High-level languages need not be slower than low-level ones.     Why use need not instead of do not need? What does it mean? Also, why no to before be?


When scanning one of the domains I have installed SSL for with ssllabs.com, Certificate #1 verifies correctly with grade 'A', although further down on the result page there is also a Certificate #2 that seems to be collected from the first of the domains with SSL certificate configured from the apache configuration for some reason and which of course gives a "MISMATCH" since the domain does not match the certificate. Wondering if anyone can point out whats wrong with the config.  Currently I'm setting up each domain hosted for ssl like this (domain names changed):  <Directory /home/info/>   Options -Indexes +FollowSymLinks -Multiviews   AllowOverride All   Order allow,deny   allow from all   Require all granted </Directory>  <VirtualHost _default_:443>   DocumentRoot /home/info/pub/   ServerName domain.at   ServerAlias domain.at www.domain.at    SSLEngine on   SSLCertificateFile    /home/info/ssl/at.crt   SSLCertificateKeyFile /home/info/ssl/at.key   SSLCertificateChainFile /home/info/ssl/at.ca </VirtualHost>  <VirtualHost _default_:443>   DocumentRoot /home/info/pub/   ServerName domain.dk   ServerAlias domain.dk www.domain.dk    SSLEngine on   SSLCertificateFile    /home/info/ssl/dk.crt   SSLCertificateKeyFile /home/info/ssl/dk.key   SSLCertificateChainFile /home/info/ssl/dk.ca </VirtualHost>  <VirtualHost _default_:443>   DocumentRoot /home/info/pub/   ServerName domain.fr   ServerAlias domain.fr www.domain.fr    SSLEngine on   SSLCertificateFile    /home/info/ssl/fr.crt   SSLCertificateKeyFile /home/info/ssl/fr.key   SSLCertificateChainFile /home/info/ssl/fr.ca </VirtualHost>   So when for example scanning "domain.fr" with ssllabs it validates correctly for .fr certificate, but then goes on to try and validate "domain.at". Should I comment out the "domain.at" config, it would try to validate "domain.dk" instead. Why is this? Grateful for help.

My apache2 configuration is problematic: I've two website on a server:   domain1.tdl domain2.tdl   One of them (domain2.tdl) must be and is accessible on port 443 (with SSL). All domains must be and are accessible by port 80. But when we try to access to domain1.tdl on port 443 the domain2.tdl files are display. So, on port 443, domain2.tdl is accessible by domain1.tdl and domain2.tdl. I don't want it !  My configuration:  domain1.tdl:  <VirtualHost *:80>   DocumentRoot /home/sites/domain1.tdl/www   ServerName domain1.tdl   ServerAlias www.domain1.tdl   ServerAdmin xxx@mail.com   RewriteEngine on   <Directory "/home/sites/domain1.tdl/www">     AllowOverride All     allow from all     Options -Indexes   </Directory> </VirtualHost>  <VirtualHost *:443>   DocumentRoot /home/sites/domain1.tdl/www   ServerName domain1.tdl   ServerAlias www.domain1.tdl   ServerAdmin xxx@mail.com   RewriteEngine on   <Directory "/home/sites/domain1.tdl/www">     AllowOverride All     allow from all     Options -Indexes </Directory>   domain2.tdl:  <VirtualHost *:80>   DocumentRoot "/home/sites/domain2.tdl/web"   ServerName domain2.tdl   ErrorLog /var/log/apache2/site/error_domain2.tdl.log                 CustomLog /var/log/apache2/site/access_domain2.tdl.log combined   <Directory "/home/sites/domain2.tdl/web">     allow from all     Options -Indexes   </Directory>   ServerAlias www.domain2.tdl </VirtualHost>  <VirtualHost domain2.tdl:443>   DocumentRoot "/home/sites/domain2.tdl/web"   ServerName domain2.tdl   ErrorLog /var/log/apache2/site/error_domain2.tdl.log   CustomLog /var/log/apache2/site/access_domain2.tdl.log combined    SSLEngine on   SSLCertificateFile /etc/ssl/private/domain2.tdl/domain2.tdl.crt   SSLCertificateKeyFile /etc/ssl/private/domain2.tdl/domain2.tdl.key   SSLCACertificateFile /etc/ssl/private/domain2.tdl/GandiStandardSSLCA.pem   SSLVerifyClient None    <Directory "/home/sites/domain2.tdl/web">     allow from all     Options -Indexes   </Directory>   ServerAlias www.domain2.tdl </VirtualHost>


I am gradually getting the hang of using Git with WordPress but I have a question that's hopefully a simple answer.   I have set up my local environment which I am happy with and using BitBucket as a private repo.   I push to my staging server when I'm happy with my local development.   Then once the client approved the staging site, it's then pushed to production.   The client has access to the production site and may make changes to the blogs (I understand this is merely database work only) and uploads some pictures.   If the client asks for some changes to the style of the site, is it good practice to then pull the production version (new images etc) and pull the database using WP Db Migrate Pro back to my local server to start working and then proceed with staging to production as before?  Should I merely just pull the theme files if they want some theme changes? Or pull everything if they require me to upload new images etc.

I know this question has been asked a thousand times, but I'm really trying to work out how to get the best out of Git when working with WordPress.  I've scoured the web and read dozens of articles, all that seem to cover the topic briefly. Here's a few of the most notable one's I've read recently.        Currently, my workflow looks like this.   Install WordPress locally Develop Theme Export WordPress Databases from local server Import WordPress Database to remote server Upload WordPress files and theme via FTP Client makes changes Download WordPress files and theme via FTP and export WordPress Databases from remote server Replace files locally Make development changes Re-upload via FTP, export and import database to remote server   I realise Git can streamline this process. It seems the best way to do this is to have a .gitignore file that ignores certain directories that don't need to be tracked, as well as having both a local and remote wp-config.php file.  But how do you handle the databases? Clients will usually make changes (posts/pages/plugins). Do I still need to export from the remote database and import back on my local server?  Can someone suggest the best workflow for me here? And walk me through the steps.  Also, I'd probably like to use Bitbucket as private repos with them are free, unlike GitHub.  Any help would be appreciated.  Thanks in advance!


Use the unique prime factorization property of $\mathbb{Z}$ (fundamental theorem of arithmetic) and the Schroeder-Bernstein theorem to show that  $$| \mathbb{N} | = | \mathbb{N} \times \mathbb{N} |.$$  Anyone knows how to start this question?  I know that Schröder–Bernstein theorem, states that, if there exist injective functions f : A → B and g : B → A between the sets A and B, then there exists a bijective function h : A → B.  But then I don't know how to apply it to this question and write a detailed approach to it. Help would be appreciated.

Show that $| \mathbb N | = | \mathbb N \times \mathbb N |$, i.e., the cardinality  of $\mathbb N$ is the same as the cardinality of $\mathbb N \times \mathbb N$.   How do I show it using the Fundamental Theorem of Arithmetic and the Schröder–Bernstein Theorem?


Can anyone please help me with this integral?  I perform a couple of substitutions and a couple of integration by parts and I get onto the right track I feel but then I get to a point where I have:  $\frac{e^{3x}\sin(5x)\ dx}5 - 3(\frac{3\int \cos(5x)e^{3x} \ dx}5 )-$... a whole bunch of other stuff all over 5 and then over 5 again (I won't annoy any further you with my inability to format correctly).  But...I have my original integral in the equation? And I put it into a solver and they have the same thing? So how can this ever be solved? I don't get it!

I need to evaluate the following function and then check my answer by taking the derivative: $$\int e^{ax}\cos(bx)\,dx$$ where $a$ is any real number and $b$ is any positive real number.    I know that you set $u=\cos(bx)$  and $dv=e^{ax} dx$, and the second time you need to integrate again you set $u=\sin(bx)$ and $dv=e^{ax}dx$ again.  It eventually simplifies down to $$\int e^{ax}\cos(bx)dx = \frac{1}{a}e^{ax}\cos(bx) + \frac{b}{a}\left(\frac{1}{a}e^{ax}\sin(bx) - \frac{b}{a}\int e^{ax}\cos(bx)\,dx\right).$$  Now I know to move the integral on the left side to the right side so that I can just divide by the constant to solve.  Here is my problem:  I know I need to solve the right side to be:  $$\frac{e^{ax}\left(a\cos(bx) + b\sin(bx)\right)}{a^2+b^2} + C.$$  To divide by the constant, I multiplied everything on the right side by  $$\frac{a^2}{b^2+1}.$$ but this leads me to get $b^2 + 1$ on the bottom instead of $a^2 + b^2$.  I will show what I am doing in detail:  After setting the initial integral equal to: $$\frac{1}{a}e^{ax}\cos(bx) + \frac{b}{a}\left(\frac{1}{a}e^{ax}\sin(bx) - \frac{b}{a}\int e^{ax}\cos(bx)\,dx\right) + C$$ I simplify: $$\int e^{ax}\cos(bx)\,dx = \frac{a^2}{b^2+1}\left(\frac{1}{a}e^{ax}\cos(bx) + \frac{b}{a}\left(\frac{1}{a}e^{ax}\sin(bx)\right)\right) + C$$  If this is already wrong, can someone point be in the right direction?    If I have not gone wrong yet, I can edit to show the rest of my work.


Message as below; tried deleting backups (not all) but to no avail. Changed to blank USB drive and received same message. Any help appreciated.  "E: Malformed entry 52 in list file /etc/apt/sources.list (Component) E: The list of sources could not be read."

I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that.  I just tried to upload a screen shot but since I'm new it won't allow me to.  I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following:  COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse)  E: The list of sources could not be read.,  E: The package list of status file could not be parsed or opened.   How do I report bugs?  What can be done about this.  I have searched and everything everyone says to do leads me back to the same line error message.  So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software.


This is a follow up topic from  previous post.  The Fourier series for $f(x)=e^x$ is $$f(x)=e^x=\sinh1\left(1+2\sum_{n=1}^{\infty}\frac{(-1)^n}{(n\pi)^2+1}\left(\cos(n\pi x)-n\pi\sin(n\pi x)\right)\right)$$  The value of the Fourier series $f(x)=e^x$ at $x=2$ and $x=1$ are the same: $$f(2)=\sinh1\left(1+2\sum_{n=1}^{\infty}\frac{(-1)^{n}}{(n\pi)^2+1}\right)$$  $$f(0)=e^0=\sinh1\left(1+2\sum_{n=1}^{\infty}\frac{(-1)^{n}}{(n\pi)^2+1}\right)$$  Could someone please prove that  $$\sinh1\Bigl(1+2{\sum}_{n=1}^{\infty}\frac{(-1)^{n}}{(n\pi)^2+1}\Bigr)=1?$$ The interval is $-1\lt x \lt 1$  Thank you.

The question given to me was: Find the Fourier series for $f(x) = e^x$ over the range $-1\lt x\lt 1$ and find what value the expansion will have when $x = 2$?  The Fourier series for $f(x)=e^x$ is $$f(x)=e^x=\sinh1\left(1+2\sum_{n=1}^{\infty}\frac{(-1)^n}{(n\pi)^2+1}\left(\cos(n\pi x)-n\pi\sin(n\pi x)\right)\right)$$  My attempt to compute these values: $$f(2)=\sinh1\left(1+2\sum_{n=1}^{\infty}\frac{(-1)^{n}}{(n\pi)^2+1}\right)$$  $$f(0)=e^0=\sinh1\left(1+2\sum_{n=1}^{\infty}\frac{(-1)^{n}}{(n\pi)^2+1}\right)$$  The answer given was: The series will converge to the same value as it does at $x = 0$, i.e. $f(0) = 1$.  Could someone please explain to me the difference between:      What value will the expansion take at a given $x$ and the value the series converges to for a given $x$?    Many Thanks


I am trying to change boot order on my UEFI GPT system (because of preinstalled Windows 8.1) on my HP Envy 15.  Successfully installed ubuntu alongside windows. Boot-repair said it successfully did the job (default boot ubuntu (grub)) but it still auto boots to Windows.  I tried command efibootmgr which seemingly did job, but after restart it was still the same  $ sudo efibootmgr -v BootCurrent: 0006 Timeout: 2 seconds BootOrder: 0001,3001,0002,0003,0006,2001,2002,2003 Boot0000* Notebook Hard Drive   BIOS(2,500,00)................-.U.......U.A.U............................................A......................... Boot0001* Windows Boot Manager  HD(2,c8800,82000,da584079-a49f-42a6-ab07-612e1667dd3f)File(\EFI\Microsoft\Boot\bootmgfw.efi)RC Boot0002* Windows Boot Manager  HD(3,14a800,82000,a49435dc-57eb-4974-8b37-87f1f0a073dd)File(\EFI\Microsoft\Boot\bootmgfw.efi)RC Boot0003* ubuntu    HD(3,14a800,82000,a49435dc-57eb-4974-8b37-87f1f0a073dd)File(\EFI\ubuntu\shimx64.efi)RC Boot0006* ubuntu    HD(2,c8800,82000,da584079-a49f-42a6-ab07-612e1667dd3f)File(\EFI\ubuntu\shimx64.efi) Boot2001* USB Drive (UEFI)  RC Boot3000* Internal Hard Disk or Solid State Disk    RC Boot3001* Internal Hard Disk or Solid State Disk    RC Boot3002* Internal Hard Disk or Solid State Disk    RC Boot3003* Internal Hard Disk or Solid State Disk    RC   setting the order   $ sudo efibootmgr -o 0006,0001,0000 BootCurrent: 0006 Timeout: 2 seconds BootOrder: 0006,0001,0000 Boot0000* Notebook Hard Drive Boot0001* Windows Boot Manager Boot0002* Windows Boot Manager Boot0003* ubuntu Boot0006* ubuntu Boot2001* USB Drive (UEFI) Boot3000* Internal Hard Disk or Solid State Disk Boot3001* Internal Hard Disk or Solid State Disk Boot3002* Internal Hard Disk or Solid State Disk Boot3003* Internal Hard Disk or Solid State Disk   after restart it's the same as in the beginning.  I even tried to setup in Windows 8.1   bcdedit /set {bootmgr} path \EFI\ubuntu\shimx64.efi   but it returned error something like "can't access drive", even though I manually mounted ESM partition. The same error using EasyBCD utility...  My "BIOS" can't select boot partition, just drive...  Any experience with laptop firmware upgrade?

My computer is a Sony Vaio Notebook. I used Ubuntu and Win 8 with dualboot but windows somehow managed to remove the menu to choose the OS at startup. I think the BIOS is UEFI. Secure boot was disabled already and Boot Repair somehow fails.  How can I fix this?


I have a login problem with a game (league of legends - the login server did not respond).I found somewhere that I need to install lib32-gnutls to fix this problem, but I don't know how to do this.  I downloaded the files from here:   Inside the folder lib32-gnutls are these files:   libgnutls-openssl.so         libgnutls.so.28            libgnutlsxx.so.28.1.0 libgnutls-openssl.so.27      libgnutls.so.28.41.0  pkgconfig libgnutls-openssl.so.27.0.2  libgnutlsxx.so libgnutls.so                 libgnutlsxx.so.28   I tried to install them through terminal with:  sudo apt-get install 'the name of the file'  but I get:  Reading package lists... Done Building dependency tree        Reading state information... Done W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main i386 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-i386_Packages) W: You may want to run apt-get update to correct these problems E: Unable to locate package libgnutls.so.28 E: Couldn't find any package by regex 'libgnutls.so.28'       I have ran the command apt-get update.  So what should I do next?

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.  Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?


I recently joined SO and related sites, and whilst raising a question I noticed that there was no obvious way for me to apply Markdown styling to body content via mobile.  For instance, if I were to post a section of code, I would have to rely on another user to edit my post to correct the formatting, or I would have to go to a desktop browser to do so. I also noticed that when tapping into the body section, mobile browsers zoom in (likely due to font-size) which makes the editing/creation experience a little jarring/unfriendly.

On the full site, there's that helpful Markdown toolbar above the post box:   This is conspicuously missing in the mobile site:   It's difficult just to get a bracket on my iPad. Backticks aren't even available. If there's a view that really needs it, i vote mobile.


Given two postive rational numbers $x$ and $y$ such that $x<y$, how do you prove that there exists a rational number $r$ such that $x<r^2<y$. I am aware that since  $\mathbb{Q}$ is dense in $\mathbb{R}$, and $x$ & $y$ are positive, there exists a rational number $r$ such that $\sqrt{x}<r<\sqrt{y}$. But I would like a proof which gives such a rational number, while just staying within the context of the rational number system.

I would like to prove the existence of $b \in \mathbb Q$ such that $a<b^2<c$ for any given $a,c \in \mathbb Q$ with $a,c>0$  I want to use the statement above to prove a statement in a  I thought that '$b$' must be exist. But, in my opinion, $\sqrt{}$ can't not be used because $\sqrt{a}$ or $\sqrt{c}$  may not exist in $\mathbb Q$ for some $a$ and $c$.  I couldn't find a clue to prove the statement before the real number is constructed from $\mathbb Q$. Would you help me to prove that?  Thanks all for replying and pointing out errors.


This is part of Exercise 2.7.9 of F. M. Goodman's "Algebra: Abstract and Concrete".  Definition 1: The commutator subgroup $C$ of a group $G$ is the subgroup generated by all elements of the form $xyx^{-1}y^{-1}$ for $x, y\in G$. The Question: Show that the commutator subgroup $C$ of a group $G$ is normal and that $G/C$ is abelian.  My Attempt: Let $g\in G$. Then $g(xyx^{-1}y^{-1})g^{-1}=gxy(gyx)^{-1}$, but I don't know where to go from here. What I'm trying to do is write $g(xyx^{-1}y^{-1})g^{-1}$ as an element of $C$. Please help :)

If $G$ is a group and $G'$ is generated by $\{xyx^{-1}y^{-1}|x,y\in G\}$, then $G'\trianglelefteq G$ and  $G/G'$ is Abelian.  At first, I thought this is easy because I thought $g[x,y]g^{-1}=[gxg^{-1},gyg^{-1}]$. But it was a mistake. I could not prove that it is also subgroup of G and $G/G'$ is abelian. I need help.


Recently there are a few changes in Flagging term on meta site. Due to this there was some flag counting problem in profile's helpful flag. Now it looks .  But just now when I click on the flag link, I found that there is increase of number in flag a post, have a look at following image,    As you can see Now I can flag maximum 61 post ( I have already used one, so it's showing 60 in image ). This change has come suddenly So, I think this is again due to that flag changes problem, because till I remember I was having flag count around 40 something. It shows same count for Spam & Offensive flag also. Edit Now It looks that this new flag weight system has been applied in Stack Overflow too, I just logged it and found that my flag weight is being increased from 46 to 100 (yesterday night it was 46), see the following images,    Even Spam & Offensive flag weight is also increase and lost it's red color.    Kindly look into this and fix it.

Looks like flagging has been affected by releases today. Are these intended effects?   Higher daily limits (appear doubled for me, flagging of posts limit also doubled).  Explained by Shog9 below. Soft comment deletion  - e.g. for "accept rate" obsolete comments - it does in fact work, but the immediate feedback is gone.  This is fixed now. Has the throttling rate changed?  Seems possible to repeated flag without waiting 5 seconds.  If it was broken, it isn't anymore. Old soft deletions that were neither categorised as "helpful" or "declined" have all become "helpful".   If limits have been updated, can we get the new formula published? Not changed, as confirmed by Shog9.


I upgraded from Ubuntu 14.10 to 15.04 and since then when I use the proprietary Nvidia driver Ubuntu doesn't boot.   It shows "Starting 219" on my secondary screen and on my primary screen it shows something like "Starting Display Manager" and at this point it gets stuck.

I've tried to install maybe ten Linux distros on my new PC, and every time I have problems with video drivers: black screen or visual artefacts.  I was able to install only Ubuntu 12.04.3 64-bit, but also with problems: black screen on startup (sometimes all was normal when I used Live mode before install, sometimes I was not able to load Live Mode - Ubuntu says that I have problems with video and gives me a choice with four elements, one of them "use safe graphics mode", but I even can't choose this - the system is frozen).   In tty I installed nvidia-current, but it didn't help me. Every boot I need to press ESC and enter rescue mode and just press Resume and after this the system boots normally. If I try to do a normal restart I get a black screen after Ubuntu logo again.  I tried switching nvidia driver in the options - I have version 319-updates and version 319 [Recommended], but neither works.  I have Palit GeForce GTX650, all updates.


In  they suggest to always use Single class imports, but they don't give a reason. What are the reasons to adopt this style of importing single classes instead of *?  Also, side question, how to I set up IntelliJ to optimize my imports in this fashion?

It is much more convenient and cleaner to use a single statement like  import java.awt.*;   than to import a bunch of individual classes  import java.awt.Panel; import java.awt.Graphics; import java.awt.Canvas; ...   What is wrong with using a wildcard in the import statement?


I'm a grad student and stats beginner just trying to make sure I'm using the right model and using it correctly. I'm using R version 3.5.0. My data look like this:      Nest_ID  Treatment  BCI   1     001        NTC 2.18   2     001        NTC 2.54   3     001        NTC 2.23   4     001        NTC 2.33   5     001        NTC 2.37   6     002        NTC 2.10   7     002        NTC 2.61   8     002        NTC 2.51   9     002        NTC 2.18  10     002        NTC 2.40  11     003         A1 2.15  12     003         A1 2.29  13     003         A1 2.45  14     003         A1 1.80  15     003         A1 2.15 77     004         C1 2.31 78     004         C1 2.21 79     004         C1 2.54 80     004         C1 2.29 81     004         C1 2.38   I have multiple BCI data points for each nest and 5 treatment groups. I want to know if there are differences in BCI between the treatment groups, but each BCI corresponds to individuals from the same nest, and each nest received the same treatment. So at first I took the average BCI from each nest to get a single BCI from each nest and ran an ANOVA on it. This seemed to work fine, but a colleague told me I could use glm and it would account for the fact that I have multiple individuals from a nest that received the same treatment. I tried glm in R, and I don't see how it's accounting for the nest being the lowest statistical unit.   GLM <- glm(BCI ~ Treatment, data = Data)   When I use this formula, my results come back significant when I don't think they should be. They came back not significant when I just took the average BCI from each group. Thanks in advance for any guidance!

I'm a grad student and stats beginner just trying to make sure I'm using the right model and using it correctly. I'm using R version 3.5.0. My data look like this:   Nest_ID Treatment  BCI 1    001       NTC 2.18 2    001       NTC 2.54 3    001       NTC 2.23 4    001       NTC 2.33 5    001       NTC 2.37 6    002       NTC 2.10 7    002       NTC 2.61 8    002       NTC 2.51 9    002       NTC 2.18 10   002       NTC 2.40 11   003       NTC 2.15 12   003       NTC 2.29 13   003       NTC 2.45 14   003       NTC 1.80 15   003       NTC 2.15     I have multiple BCI data points for each nest and 5 treatment groups. I want to know if there are differences in BCI between the treatment groups, but each BCI corresponds to individuals from the same nest, and each nest received the same treatment. So at first I took the average BCI from each nest to get a single BCI from each nest and ran an ANOVA on it. This seemed to work fine, but a colleague told me I could use glm and it would account for the fact that I have multiple individuals from a nest that received the same treatment. I tried glm in R, and I don't see how it's accounting for the nest being the lowest statistical unit.  GLM <- glm(BCI ~ Treatment, data = Data)   When I use this formula, my results come back significant when I don't think they should be. They came back not significant when I just took the average BCI from each group. Thanks in advance for any guidance!


What is the name, if there is one, for the following dialog type?    Are there any alternatives?

Couple of us arguing about this and none of us can remember what this is or would be called. Commonly seen on forms where you are moving an option from one box on the left to a box on the right and commonly has buttons in between the two boxes to move a singular option or all options. Crude visual example below (since we can't remember it enough to search for an actual example).  ------------         ------------------- | Option 1 |         | Selected Option | | Option 2 |   ->    |                 | | Option 3 |   -->   |                 | | Option 4 |   <-    |                 | | Option 5 |   <--   |                 | | Option 6 |         |                 | ------------         -------------------   What would this be called?  ...and, no, you don't have to tell me how mind-blowingly and award winning my illustration is. I am aware. :)


please could you help with the regex to get everything unto the ";"..  window.egfunc = {   name: "test name",   type: "test type",   storeId: "12345" };   I have the following which works when all the data would be on one line, but as soon as there are returns, it won't work...  window.egfunc\s+=\s+(.*);

For example, this regex  (.*)<FooBar>   will match:  abcde<FooBar>   But how do I get it to match across multiple lines?  abcde fghij<FooBar>


While working on my project, I completely rigged only one half of a mesh without the mirror modifier applied. I obviously want the whole thing rigged - Am Ia forced to redo the whole thing to get the other side? (Is there a way to just mirror the whole thing with the rig data?)

I need to mirror the half part of the rigging of my character, I remember it was something with the scale or rotation.. does anyone know which was the right solution step-to-step?


I have a 2019 13-inch MacBook Pro with 2 Thunderbolt 3 ports and an 21.5-inch Late 2009 iMac. The MacBook is operating on Big Sur (11.4), and the iMac is operating on High Sierra (10.13.6). Is it possible to mirror my MacBook onto my iMac, despite the difference in OS? I currently have a Thunderbolt 2 to USB-C cable, if that helps.

I have a Surface Pro 4 and an iMac (late 2019). I would like to connect my Surface Pro to the iMac to use the iMac screen as a second monitor.  Is that possible?  What are the requirements to use an iMac as a second screen?


When creating a struct, I often zero it using struct initialization: struct MyStruct data = { 0 };  However, I have a very large (200mb) struct that I'm allocating, and because it has strict alignment needs (math library using AVX), I'm allocating it using _mm_alloc: struct MyStruct* data = (struct MyStruct*)_mm_malloc( sizeof (struct MyStruct), 32 );  To zero this struct, memset works fine. However, if I try to use struct initialization here, it crashes with a Segmentation Fault: *data = (struct MyStruct) { 0 };  Am I doing this improperly for a dynamically allocated struct? Or is there some other reason why a strictly-aligned block of allocated memory can't be initialized in this way?

The following code is generating a stack overflow error for me  int main(int argc, char* argv[]) {     int sieve[2000000];     return 0; }   How do I get around this? I am using Turbo C++ but would like to keep my code in C  EDIT:  Thanks for the advice.  The code above was only for example, I actually declare the array in a function and not in sub main.  Also, I needed the array to be initialized to zeros, so when I googled malloc, I discovered that calloc was perfect for my purposes.  Malloc/calloc also has the advantage over allocating on the stack of allowing me to declare the size using a variable.


i want know javascript is disabled by browser if yes than how can i enabled.

There was a post this morning asking about how many people disable JavaScript. Then I began to wonder what techniques might be used to determine if the user has it disabled.   Does anyone know of some short/simple ways to detect if JavaScript is disabled? My intention is to give a warning that the site is not able to function properly without the browser having JS enabled.   Eventually I would want to redirect them to content that is able to work in the absence of JS, but I need this detection as a placeholder to start.


I'm making a guitar, and i found that the easiest way was to make the body, the neck and other few details separatly. But i don't know much about how that affects the render and all that, i think that i have to join them, but the problem is. If i ctrl+j and join them, would i need to join the two meshes by joining vertices or i can leave them like that and is all fine?. And example, here is the headstock of my guitar, i made the cylinders as an independent mesh and i find it difficult to join vertices. How that would affect the end result?

Is there any benefit of creating model in one piece or I can create separate pieces and just overlap them to create a visually joint part.  For example, the below image were made from two parts 1. Blade 2. Spinner  Is there any benefit to model them (e.g. extrude from the spinner) or it is actually ok to have them separated since visually I can achieve the same effect (See picture 2)


I understand that SO is the most popular SE site, but what percent of users start there? How often do people come initially to the other SE sites and then perhaps join SO?  Is this a statistic that can be pulled up by site?   The real reason I want to know this is that if I am seeing an opinion of people on Writers let's say 50 people agree and upvote, am I 99% seeing the opinion of 50 programmers who are also sometimes write, and missing out on the general population?

Are there any pages/dashboards showing cross-site statistics indicating new enrollments, how many users become active on multiple sites, perhaps broken down to show the first website that new users joined?  For example, I first joined  and then got hooked to the QA format and joined several other SE sites.


I am new using QGIS and struggling with this error "...... .asc is not a supported raster data source" when trying to add a ."asc" file as a raster.   I downloaded the files from   I tried Layer: Add Raster Layer, and also Raster: Conversion: Translate (convert format) but neither recognized the .asc

Further to , I have .nc and .asc files of crop area and production for maize, rice and wheat. , about QGIS importing .asc files:     QGIS has native support for this format.   ESRI grid (.asc) files can   be directly opened in QGIS by selecting Layers >>> Add Raster Layer.    The .asc file can also be dragged and dropped into the QGIS session, rather than using the Add Raster Layer option.   But when I do either, I get this error:      .asc is not a supported raster data source.     which has been reported at    I am using version 2.0.1-Dufour.