I installed Ubuntu server 16.04 and installed services I want. And now I want to create my customized ubuntu image from this server.  How could I do it?

I'd like to create a customized Ubuntu Server 12.04 ISO but couldn't find a clear approach on how to do it. I see that Ubuntu-builder is a very good app to create a customized Ubuntu Desktop, but what about Ubuntu Server?


I have a list which looks like this:  some_list = [{'id':1, 'name':'Steve', 'age':23}, {'id':2, 'name':'John', 'age':17}, {'id':3, 'name':'Matt', 'age':31}]   I would like to sort the list my the name value in the dictionary. So Instead of the above order, it would be John then Matt then Steve.  How would I go about this? Thanks.

I have a list of dictionaries and want each item to be sorted by a specific value. Take into consideration the list: [{'name':'Homer', 'age':39}, {'name':'Bart', 'age':10}]  When sorted by name, it should become: [{'name':'Bart', 'age':10}, {'name':'Homer', 'age':39}]


I want to be able to get an OrderBy query working with a lambda expression so that I get a SQL query with the TOP(n) key word (big performance boost).  I am able to do this if I specifiy ...  PaginatedList = query.OrderBy(x => x.QuoteID).Skip(() => skipValue).Take(() => pageSize)   But because I want the orderBy field to be dynamic through a UI selection of a name I want to do something like this:  var propertyInfo = typeof(Data.Quote).GetProperty(sortName); Expression<Func<Data.Quote, object>> orderField = x => propertyInfo.GetValue(x, null); PaginatedList = query.OrderBy(orderField).Skip(() => skipValue).Take(() => pageSize)   This gives me the error:      "LINQ to Entities does not recognize the method 'System.Object   GetValue(System.Object)' method, and this method cannot be translated   into a store expression."   I tried this that's not of type Expression<Func<T, object>>  var propertyInfo = typeof(Data.Quote).GetProperty(sortName); Func<Data.Quote, object> orderField = x => propertyInfo.GetValue(x, null); PaginatedList = query.OrderBy(x => orderField).Skip(() => skipValue).Take(() => pageSize)   And I get this error:     "Unable to create a constant value of type [...]. Only primitive types   or enumeration types are supported in this context"   I'm sure there is a way to achieve this but at the moment not sure how.

I found an example in the  for Dynamic LINQ that allows you to use a sql-like string (e.g. OrderBy("Name, Age DESC")) for ordering. Unfortunately, the method included only works on IQueryable<T>. Is there any way to get this functionality on IEnumerable<T>?


Problem  Suppose a finite set $G$ is closed under an associative product and that both cancellation law hold in $G$. Prove that $G$ must be a group. Also show by an example that if one just assumed one of the cancellation laws holds, then the conclusion need not follow.  This is from Topics in Algebra by Herstein Specific question How can I prove the properties of group from the both cancellation laws? In short, the identity and invertibility. If $a$ and $b$ belong to $G$ then $ab$ belongs to $G$ (closure property), but does it imply that  it has an identity element.

Let $G$ be a non-empty finite set with an associative binary operation so that cancellation law holds, i.e. $ab=ac$ or $ba=ca$ implies $b=c$, for any choices of $a,b,c$ in $G$. Assume that there is an identity element $e$ in $G$. Show that $G$ is a group.  Proof: To show $G$ is a group, conditions must hold. Suppose that $ab=ac$, then $b=eb=(a^{-1}a)b =a^{-1}(ab)=a^{-1}(ac) =(a^{-1}a)c=ec=c$. So left cancellation holds in $G$.  2) Suppose $ba=ca$, then $b=be=b(aa^{-1}) =(ba)a^{-1}=(ca)a^{-1} =c(aa^{-1})=ce=c$. So right cancellation holds in $G$.  3) If $a$ exists in $G$ then $aa^{-1}=a^{-1}a=e$, where $a$ is an inverse of $a^{-1}$. Since inverses are unique, $(a^{-1})^{-1}=a$.  4) Let $x$ be the inverse of $ab$. Then $(ab)x=e$. By associativity we have $a(bx)=aa^{-1}$. Through left cancellation we have  $bx=a^{-1}bx=ea^{-1}=b(b^{-1}a^{-1})$ and $x=b^{-1}a^{-1}$.  Thus $(ab)^{-1}=b^{-1}a^{-1}$. So all conditions hold, $G$ is a group.  Is this proof correct? I know to show $G$ is a group these conditions have to be met. This is all I have to show right?


On the last move, after only 2 train pieces remains, is it possible to claim a 3-carriage route, if you have the 3 required color cards but only 2 plastic trains left to place on the board?

A recent quandary came up with some friends in a game of Ticket to Ride.  If, in the last turn, you have the cards to play a route longer than the number of trains that you have left, can you do so?  Or are you limited by your number of trains?


Could someone kindly explain why the following works:  \documentclass{article} \usepackage{tabular} \newcolumntype{C}[1]{>{\centering}m{#1}} \newcolumntype{L}[1]{>{\centering}m{#1}} \begin{document} \begin{center}   \begin{tabular}{ | L{3cm} | C{3cm} | r | }     \hline     A & B & C \\ \hline     1 & 1 & 16384 \\     \hline   \end{tabular} \end{center} \end{document}   But if I try to include the following, it fails(?):  \newcolumntype{R}[1]{>{\centering}m{#1}}   Many thanks

I would like to create a table with some columns' width specified, while the text in those columns should be centered both horizontally and vertically. I found out that  \usepackage{array} \begin{tabular}{| c | c | m{5cm} |}   vertically centers the text in the last column, but justifies it horizontally (like text in normal paragraphs).  Update: With Jake's method, it seems both \\ and \hline cause an error. How to fix it?


I read some where that an electronic device will only draw the required current for its operation but i dout a device working at 5 volt 500 mah will burn at 5 volt 3 amp source is this true or will it work fine?

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


Found some info in Wikipedia and some info in blog, but is there longer (full) story available somewhere?

I'd like to know how Stack Overflow and other sites started - which was first, who initiated it (OK, that's on the link below) and why, how the different sites evolved, how the rules evolved, etc.  Where can I find such information?  Of course, I know I can look at  for a brief overview but I'm wondering if there is info on this site, particularly more detailed..


In The Empire Strikes Back, Yoda is initially reluctant to teach Luke, it takes the Ghost of Christmas Past Obi-Wan and Luke to convince him.   But in Revenge of the Sith it seems this is the plan, is there a reason for this seeming change of heart?

Our (and Luke's) original impression of Yoda is by no means flattering. He looks like a crazy hungry green thing that unfortunately has the ability to speak. Yoda digs through Luke's stuff, eats Luke's food, and, obsessed with that awesome little flashlight, ends up stealing it. (He even goes so far as to fight with Artoo over it.)  So was Yoda slowly losing it during all those years as a hermit?  Perhaps going from fighting battles and conversing with others on a daily basis to living in total isolation with no one to speak with would play a part in that? Or could Yoda have been faking his apparent insanity for some reason? (If so, what is mentioned reason?)


I'm trying to show that if $f(z)$ is analytic an $|f(z) - 1| < 1$, then $\int_\gamma \frac{f'(z)}{f(z)}dz = 0$ over all closed curves $\gamma$. Presumably, I need to show that this is an exact differential. I can rewrite $\frac{f'(z)}{f(z)}dz$ as $$\frac{f'(z)}{f(z)}dz = \left(\frac{1}{u + iv} \frac{\partial u}{\partial x} + \frac{v + iu}{u^2+v^2}\frac{\partial v}{\partial x}\right)(dx + idy);$$ however, now I need to find some $F(z)$ such that the partial derivatives of $F$ form the expression above (multiplied by $i$ for the partial on $y$). My idea was to show that both the real and imaginary parts of the differential are exact to simplify it a bit, but my algebraic manipulations don't seem to go anywhere. Is there something I'm missing; perhaps the $|f(z) - 1|<1$ condition? (For now, I'm assuming that that's just there so the denominator is not zero).

Let $f$ be an analytic function, $C^1$ on an open and connected set $U$.  for all $z\in U$ : $|f(z)-1|<1$.  Prove that $\int_\gamma \frac{f'(z)}{f(z)}dz =0$ for every closed curve (closed curve- $\gamma(a)=\gamma(b)$) in $U$.  Any hints?


Kindly use below code to reflect the error:  CREATE TABLE TESPVTBL (     Names   NVARCHAR(20),     Salary  INT,     Country NVARCHAR(80) )  INSERT INTO TESPVTBL (Names, Salary, Country)  VALUES ('Karthick', 15000, '1300029INDIA'),        ('BRO1', 15000, '130008INDIA'),        ('DHARU', 15000, 'US'),        ('DHARUBRO', 15000, 'US')  SELECT      NAMES, 1300029INDIA, 130008INDIA FROM      TESPVTBL PIVOT     (SUM(Salary)            FOR Country IN (1300029INDIA, 130008INDIA)) AS PT   Is there any way to solve this?

One of my columns is called from. I can't change the name because I didn't make it. Am I allowed to do something like SELECT from FROM TableName or is there a special syntax to avoid the SQL Server being confused?


My printer is HP LaserJet 1020 Plus. I cannot print anything, I have noticed in the settings menu "Not calibrated".   What is the procedure to calibrate? Please explain with simple language.

I'm new to Ubuntu (14.04). I have to print some documents, but I can't set up my printer (Hp laser jet 1020 plus). Please tell me the proper way to set-up and install it.


I remember watching it on HBO all the time as a kid.  Vehicle was gray, had a dome up top and possibly a dome on back.  It had huge tires strapped together with bungee cords.  It broke down and a girl shows up. Lots of creatures throughout, for example a swamp with paper-like ghouls. Eventually a thunder-dome-like setting with a bionic villain attached to some sort of robotic arm to move around, like a spider web. He had a circle-lightning-looking light behind him.

I am trying to identify a sci-fi movie from the 80's or 90's, with the following parameters:  Setting:    Scenes of a red desert planet   Culture:    Either people roam fairly solo and try to acquire resources to survive, or you live in a weird society where if a stranger is captured he needs to play in a game of fight to the death.  Mobility:      One foil character has a giant battle-bot-looking tank as his form of transportation through the desert. Protagonist has a car that has a plastic half bubble on top to look out from.   Robot:      The protagonist runs around in the beginning of the film with a female robot/android whose face is melted off after it has acid touch its face.(This scene happens next to the protagonist's rover)  Love interest:      Somehow protagonist comes across female protagonist in desert. She smells really bad and is hungry. They sleep outside, and he tells her to sleep away from him. He uses a thermal blanket(the first I ever saw in my life). She wakes up next to him, smelling horrible. He bathes her in some water hole they find(as if water were not scarce and they could just waste water.)   Pupa monsters:      Scene where they are in a building and they are trying to get out. They come across a room that is white, in which multiple giant, white, snot, pupa are hanging securely from the ceiling. Through curiosity, they disturb them, and now they have to get out of that room fast.  Boss Antagonist:      Pervert bionic man, that is actually attached to a giant robotic arm, as only form of movement. He is in black and has a pale bald head as his most human looking part.


I seek clarification, i understand when to use data types of string, integer, double etc.When exactly would i use a data type of var (Variable)?

After discussion with colleagues regarding the use of the 'var' keyword in C# 3 I wondered what people's opinions were on the appropriate uses of type inference via var?  For example I rather lazily used var in questionable circumstances, e.g.:-  foreach(var item in someList) { // ... } // Type of 'item' not clear. var something = someObject.SomeProperty; // Type of 'something' not clear. var something = someMethod(); // Type of 'something' not clear.   More legitimate uses of var are as follows:-  var l = new List<string>(); // Obvious what l will be. var s = new SomeClass(); // Obvious what s will be.   Interestingly LINQ seems to be a bit of a grey area, e.g.:-  var results = from r in dataContext.SomeTable               select r; // Not *entirely clear* what results will be here.   It's clear what results will be in that it will be a type which implements IEnumerable, however it isn't entirely obvious in the same way a var declaring a new object is.  It's even worse when it comes to LINQ to objects, e.g.:-  var results = from item in someList               where item != 3               select item;   This is no better than the equivilent foreach(var item in someList) { // ... } equivilent.  There is a real concern about type safety here - for example if we were to place the results of that query into an overloaded method that accepted IEnumerable<int> and IEnumerable<double> the caller might inadvertently pass in the wrong type.  var does maintain strong typing but the question is really whether it's dangerous for the type to not be immediately apparent on definition, something which is magnified when overloads mean compiler errors might not be issued when you unintentionally pass the wrong type to a method.


Let $s_n = 1$ and for $n \geq 1$, let $s_{n+1} = \sqrt{s_n+1}$. Given this sequence and assume that it converges. I have to prove that the limit is $\frac{1+\sqrt{5}}{2}$  By using the definition of limit, I tried to set $n > N\ implies\ |\sqrt{s_n+1}-\frac{1+\sqrt{5}}{2}| < \epsilon$. But I have no idea how to simplify the expression in the absolute value and get rid of absolute value!!! Can anyone give some hints??

(Fitzpatrick Advanced Calculus 2e, Sec. 2.4 #12)  For $c \gt 0$, consider the quadratic equation $x^2 - x - c = 0, x > 0$.  Define the sequence $\{x_n\}$ recursively by fixing $|x_1| \lt c$ and then, if $n$ is an index for which $x_n$ has been defined, defining  $$x_{n+1} = \sqrt{c+x_n}$$  Prove that the sequence $\{x_n\}$ converges monotonically to the solution of the above equation.  Note: The answers below might assume $x_1 \gt 0$, but they still work, as we have $x_3 \gt 0$.    This is being repurposed in an effort to cut down on duplicates, see here: .  and here: .


I'd like to know whether "was" or "were" should be used in the main clause of the following:     If there were a 200-story office building without an elevator, those whose office was / were on the 180th floor would climb many steps each day.   I'd appreciate your help.

Which of these sentences is correct, and why?   "What if the Moon was a Disco ball?" or  "What if the Moon were a Disco ball?"


I have a raster layer in QGIS that is stored as a three color image. I want to do some analyses on it and would like to have it just as values 1,2,3 (and then I can leave the presentation to later)   The raster is red, yellow, green and the band values are  255,0,0 0,245,0 240,240,0   So I should be able to use either the red band or the yellow band to extract my information.  This could easily be coded as  value=redband.value if value==255:     return(3) if value==240:     return(2) if value==0:     return(1)   To return red yellow and green as 3,2 and 1 respectively.  But in the field calculator, I can only see how to do mathematical expressions. Is it possible to run a script in the field calculator or do I have to rewrite this as a python script to run in the python console?  (I know it possible to turn a raster with only three distinct values into a polygon layer, but due to the structur of the raster, the polygon gets quite unwieldy and the analysis I am going to do on this later requires a raster)

Is it possible in QGIS either directly or via plugins to do a raster calculation including an if statement?  e.g., if raster1 > 0.3, then raster 1 * raster 2, else raster1 x raster3... something like that?


I wanted to have some text cut out of a steel plate, but I wanted hot/glowing edges as if it has just been cut. So far I did  Created a plane and bent/dented it with sculpting Add a solidify modifier to give it some thickness Created some text and extruded it Overlapped the text with the plate and added a boolean modifier (which is applied) to cut out the text. I applied a rusty metal material to the plate I applied a shiny metal material to the cut faces in the plate.  Now I'm stuck trying to make the metal look like it was cut with a torch. Thanks

I’m animating a plate of steel cut by laser rays. My animation is complete for the most part of it but I want to make the overheating of the steel where the laser passes visible. As it passes it assigns another material with emission on the cut border of the meshes of the plate and the borders of the cut pieces. The appearance of the material has to be animated according to the movement of the laser or even in key frames.


Let $f(x) \in C(-\infty, + \infty)$ satisfy $\displaystyle \int_{a}^{b} f^{2}(x)  dx \leqslant f(a) + f(b)$ for $\forall a,b \in R$  Prove that:$f(x) \equiv 0$  I have known that $f(x) \geqslant 0$,but I can't continue.

Let $f\in C ((-\infty,+\infty)).  $ If $ \forall  a,b\in(-\infty,+\infty),\int_{a}^{b}f^{2}(x)dx \leq  f(a)+f(b), $ then$f(x)\equiv 0$.   I can prove $f(x)\geq 0,$ so I want use the reduction to absurdity in the next proof that may refuse $f(x)>0.$ In my way of thinking ,I tried but it is seemingly difficult  to deny $f(x)>0.$ Could you please give me some hints?


I want to divide my time interval from the start time to end time.  The elapsed time should be divided across 30 minute time intervals so that for this input  08:05:13   12:09:49   I should get following output.

I want to divided my to my time interval depending to the start time and end time. To explain it further, let me have this example. I have this table:  User           Elapsed Time        Start Time            End Time User01         01:05               07-02-2015 08:45      07-02-2015 09:50   I want to divide its elapsed time to 30 minute time interval so that i will have an output like this.  Interval From        Interval To         User       Elapsed Time 07-02-2015 08:30     07-02-2015 09:00    User01     00:15 07-02-2015 09:00     07-02-2015 09:30    User01     00:30 07-02-2015 09:30     07-02-2015 10:00    User01     00:20   Thanks in advance


I am writing a scientific report for my internship, and I would like to know if there is any easy command to put a logo in the page headers , for  example in my case I would like it in the head-right.  PS: I am searching also to put two minipages in the same line and control their position (space them each other or approach them like in CV's header with names , email address and photos).

I've been learning LaTeX and this community has been very helpful. Currently, I'm trying to set up corporate letters but as a newbie I'm encountering a  of , so I'm posting them one by one instead of putting it in the comments... maybe this helps others as well.  Anyway, I am trying to implement this  that indicates that I can use vbox to float an image to the right of my header. I almost have this working, but I now try to adjust this to get my logo to stick to the top of the page. So I want to have this at the right top of my document. This is quite difficult! When I place the vbox, it creates unwanted spacing, for some odd reason. So I can not get the logo to be at the right top, even though I 'reset' every possible margin to 0 (in my opinion). Here is my distilled code:  \documentclass[a4paper]{article} \usepackage{graphicx} \graphicspath{{./img/}} \usepackage{color} \usepackage{xcolor} \definecolor{orange}{HTML}{DD4616} \definecolor{white}{HTML}{FFFFFF} \usepackage{fullpage} \usepackage[margin=0cm, paperwidth=215.9mm, paperheight=30mm,top=0cm]{geometry} \parindent=0pt  \begin{document} \fboxsep0pt  \pagecolor{orange}   \fbox{\vbox to 0pt{\hfill\fbox{\includegraphics[height=3cm]{logo}}}}  \end{document}   I've used a full black logo for illustrative purposes. Here you can see this:    The black line is the vbox border. For some reason, it jumps down. The only way to get rid of this that I found out about is this:    Which means that I need to add:  \edef\theprevdepth{\the\prevdepth}\nointerlineskip \vbox to 0pt{...}\prevdepth=\theprevdepth   But there are two problems with this:   I get an error with I try this (Improper \prevdepth.) More importantly, I really want to understand my code at this point, and get to master the basics of positioning elements. This feels overcomplicated and I do not understand it at all.    Is there any easy way to position an image at the right top of a document?


I recently became aware that the flat Earth theory still exists in the 21st century, and has colored the views of a friend of mine. Roughly speaking, the tenets are:   The Earth is a flat disk, with the south pole blown up into a circular "ice wall" where one would expect Antarctica to be.                                              The sun and moon are either spheres or disks floating above the earth and moving in a spiral pattern with the seasons. NASA is part of a conspiracy to conceal the truth, and sends us animations and faked photo shoots.   The Flat Earth Theory is a scientific theory, in the sense that it makes falsifiable predictions about the universe that can be seen to match observation (or not). What are some good arguments or backyard experiments that could convince a layman that in fact the Flat Earth Theory is false?  A similar question and useful related reading is , but it focuses more on the theoretical and conceptually simple side, applicable to the proverbial "numskull cousin". This question is more focused towards convincing a doubtful scientific person using (preferably low-tech) experiments and observations.

Assume you've come in contact with a tribe of people cut off from the rest of the world, or you've gone back in time several thousand years, or (more likely) you've got a numbskull cousin.  How would you prove that the Earth is, in fact, round?


Does anyone know where I could download a layer of all villages in India together with their populations (hopefully from the 2011 census)?

Trying to source population data for every village, town and city in India.  I have been able to extract data for 2001 & 2011 from the , but am having a tough time finding a reliable source for data from 1981 and 1991.    Any thoughts as to where this may be found?


i'm trying to represent concentration/distribution across a set of categories.  Specifically these are job types, e.g. tourism, manufacturing, transport, education.  Let's say there are 10 job types and 3 cities:   City 1: 100k jobs.  All are in tourism.   [highly concentrated]  City 2: 75k jobs, 91% in tourism, 1% in each of 9 other industries.   [highly concentrated]  City 3: 30k jobs, 10% in each of 10 industries.  [highly distributed]  I'm not a stats guy but this feels like it should be something obvious and i'm struggling to find it.  i can't see how i could use stand dev as there is no mean.

I've got an educational game in the work that challenges players to redraw U.S. state borders in a way that reduce the inequality between big-population and small-population states. As they play, they need to get real-time feedback on the effect of assigning counties from one state to another.   So I need some sort of single parameter of "equalness" that is derived from the distribution of populations in the new hypothetical set of states.   I've thought about just displayed the standard deviation in the state populations. Is there a better way to succinctly express a power distribution? I'd prefer something as simple to understand as possible since I want to appeal to a broad audience. State populations as of 2010 Census below for reference.


I'm supposed to prove that, in a ring, if $a$ is an element such that the set $\{a^n; n=0,1,...\}$ is finite, then $a$ is either invertible or a zero divisor. I don't understand how $a$ can not be invertible, since if the set is finite then there has to be an $i$ such that $a^i=1$.

Let $R$ be a finite ring with unity. Prove that every nonzero element of $R$ is either a unit or a zero-divisor.


Looking for a short story or novella where the people hide in caves during the really hot days and cold nights. They have highly accelerated life spans. The protagonist tries to journey to a metal spaceship. I think food and life outside the cave appear rapidly at morning twilight and burn to a crisp by mid-morning.

Looking for a short story where time is accelerated on a planet.  The characters are actually born at the beginning of the story and then grow up quickly and inadvertently learn that their forebears came from a rocket ship nearby.  After having aged to "teenagers" they try to reach the ship?  At some point there is a war between confused aging survivors.  I think it was in a compilation which included a story called "Cousins".


I think it's not true. But since in a group, inverse for each element exist then, we can write: $ab=e$ Multiplying by $a^{-1}$ on both sides $b=a^{-1}e=a^{-1}$ This implies that $ba=e$ Am I missing out something? Thankyou for any help or hint.

Suppose that instead of the property $ab=ba=e$ a group G has the condition that for every element $a$ there exists an element $b$, such that $ab=e$. Prove that $ba=e$. Is the following a valid proof?  Since $ab=e$ then under the condition of the group there exists an element $k$ such that $bk=e$ for some $k$ in the group.  Now $bk=e$ so $abk=ae$ therefore $(ab)k=a$ and finally $ek=a$ and $k=a$.  Is this a valid proof?


I have a professor who is teaching an upper class man renaissance art history course. I am very passionate about this subject so I already have lots of prior knowledge. I found some inaccuracies in her lectures and tried to confront her about them, providing sources and all. She still insists she is correct and graded me unfairly. Again, this is an upper class course and she teaches it like an introductory level course. The information she provides is inaccurate and she teaches by asking us to a memorize each picture and its statistics (name, date, medium, size, location), and covers none of the historical elements of the piece artist or era. I'm very frustrated with her and I'm not sure what to do.  Any advice would be greatly appreciated. Thank you.

I am an undergraduate in the UC system.  I sometimes encounter situations where professors or TA's make errors, or there are inaccuracies in the material.  These situations tend to be quite awkward for both the student and the TA or professor.    It is painful for me not to speak up, but there is a fear, possibly exaggerated, that this could lead to resentment by the TA, or professor, or even future unfair treatment.    The most frequent response by senior students is that the professor is always right, and you should never attempt to argue with the professor. Confronting a professor about a misconception could end up being detrimental to the student in the long run.    What should a student do (and how?) when a teacher makes an error or gives inaccurate information or material?  Is there any reasonable way to anonymously point out mistakes?


Everytime my Ubuntu 13.04 system loads up, update-notifier opens with a list if software that can be updated. I do not want update-notifier to open. I have checked its settings and the cron and at tables for my account. Oddly, nothing is seen that would make update-notifier to come up. How can I make it stop checking for updates and not execute?

how to permanently disable ubuntu updates pop up & hide or remove Install Updates button pic included see below:


Oddly the password works in the the command line.   I've created a new account on command line and logged to the the desktop from that. However the password of my old account no longer logs to the desktop.

I've recently  by reinstalling Ubuntu with a new username, and thankfully my old account survived (yay). Now I'd like to add my old account back to Ubuntu. Note that I'm not necessarily trying to overwrite the new user account. I just want to restore the old account and have it be the default when I boot up Ubuntu.  Edit I can create a new account under the old name but I'm worried that that will destroy the old account data.  Update  I've replaced the my new home folder with my old home folder but that didn't work.


An "alien race", when speaking about non-Earthly beings, make no sense. They would not be a "race" (of humans), but a different species. Just like a dog is not a "race" of humans, but a separate species. Within dogs, there are different races or "breeds" as they call them in that context. The point is not specifically the word "race" but the mixing-up of two very different concepts. Two individuals of the same species (such as two humans from different parts of the world) can have offspring even if they are from different races. Two individuals of different species, such as a human and a dog, cannot have offspring. Because they are different species. Of course, they are also different races, but that is only technically true and doesn't make sense in the context, since the species (which is much more fundamental) is different. So, an "alien race" (not talking about "illegal aliens" from a different country on Earth) makes no sense. It would be an alien species or, if you want to avoid the words race/species for whatever reason, an "alien life-form". So why do they keep butchering the English language when they must know better? I see this all the time in sci-fi context. The English language is being slowly morphed into absolute gibberish, even among people who clearly must know better.

It's very common -- specially in fantasy and science-fiction -- to use race instead of species. For example:  “In Middle Earth (...) Aragorn (race: men) (...) Bilbo (race: hobbit)”  “Tarkin's motivation was the enslavement of the Wookiee race for use as manual (...)” “The human race has only one really effective weapon and that is laughter.”  Shouldn't be used species instead? From the Oxford dictionary:  . Biology. a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. The species is the principal natural taxonomic unit, ranking below a genus and denoted by a Latin binomial, e.g. Homo sapiens. 2. each of the major divisions of humankind, having distinct physical characteristics: people of all races, colours, and creeds.


I've heard that when your companion needs to speak to you on SWTOR KotFE, you need to go to a cantina or your ship. I'm a Sith, so would the cantina on Korriban do? Thank you

I just finished up the last quest on Korriban, and my companion, Khem Val keeps saying, "I want to speak with you."  So... I right click him, and he says: "I want to speak with you."  So, I'm at a loss. How do I speak with the big lug?


Why is it that in python, some calculations are so much more imprecise than others? Ex. x=0.1 y=x+x+x print(y==0.3) print(y)  returns False 0.3000000000004  Whereas if I start with x as 0.25 or 0.5, print(y==0.75) and print(y==2.25) both return True.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I designed a PCB with an STM32 and a micro USB connector. I put a NUF2042XV6T1G between the connector and the STM32 to protect the data lines. The USB shield is connected to system ground via a 120R@100MHz ferrite bead.  The board has a power prioritization scheme going on, so it can be either bus powered, powered via a power supply or from a battery. I tested the prioritization circuit extensively, and the priorities and the make-before-break behaviour work just fine.  However, I noticed that when the board ground is referenced to mains earth via the power supply, the STM sometimes resets when I plug in the micro USB cable. At first I thought that the make-before-break doesn't work reliably, but that is not the case. Then I noticed that it is enough to touch the micro USB plug's shield to the receptacle's shield to crash the CPU. So I had a look at what's going on on the USB shield when not connected to my board:    Above is the shield voltage (referenced to mains earth) when the USB cable is plugged into a cheap chinese USB power supply (no mains earth connection).    Above is the shield voltage (referenced to mains earth) when the USB cable is plugged into a genuine Apple USB power supply (no mains earth connection either). Not as bad as the chinese one, but I'm still shocked (fortunately only figuratively. I don't notice anything when touching the shield with my finger).  I noticed that the CPU does not reset if I touch the USB plug's and receptacle's shield with my finger before connecting the metal parts when plugging in  So the question here is: How should I connect the receptacle's ground to the circuit ground to avoid this issue and stay clear of EMI issues? A high resistance (1M or so) instead of the ferrite bead? Both in series? Both in parallel (makes no sense to me)? Capacitively couple them?

This is about the seemingly controversial shield to ground connection. The system is basically a body-worn intel-based computer, powered by a battery. Two USB 3.0 (or 3.1 Gen1) cables come out to a PCB that contains two USB 3.0 hub chips (). Two external cameras plug in to this usb hub PCB (one camera for each hub). So the usb hub PCB has 4 usb connectors (2 upstream and 2 downstream).  The question is, what to do with each of the usb connector shields? The main directive is USB connection robustness.  I have seen many recommendations. For example:  Recommendation 1  TI's TUSB8020B hub reference design  ties all shells directly to ground.    Intel's  also recommends to tie to ground (although this was written for USB 2.0).    Recommendation 2  TI's TUSB8020B EVM (and datasheet) connect shields together, and to ground using RC filter:    Microchip's  also ties shields together and uses an RC filter, but a 3 orders of magnitude smaller R:    Recommendation 3  Cypess  ties each shield independently to ground using either LC or L filter (chokes really):    The cameras themselves (off the shelf) use Cypress recommendation (LC to ground). The embedded computer seems to tie to ground from visual inspection and checking continuity to ground, but I'm not 100% sure (schematics are not available).  Now we face the shield dilemma with the hub PCB (which by the way currently does not have a metallic enclosure, it is a 3d printed plastic enclosure).   What is your say?


It's a question about dom manipulation inside functions, I have seen code that create shopping list , it goes like this:   const list = document.querySelector('ul'); const input = document.querySelector('input'); const button = document.querySelector('button');  button.onclick = function() {   let myItem = input.value;   input.value = '';    const listItem = document.createElement('li');   const listText = document.createElement('span');   const listBtn = document.createElement('button');    listItem.appendChild(listText);   listText.textContent = myItem;   listItem.appendChild(listBtn);   listBtn.textContent = 'Delete';   list.appendChild(listItem);    listBtn.onclick = function(e) {     list.removeChild(listItem);   }    input.focus(); } li {   margin-bottom: 10px; }  li button {   font-size: 8px;   margin-left: 20px;   color: #666; }
My shopping list

     Enter a new item:     <input type="text" name="item" id="item">     <button>Add item</button>

     Now, what I don't understand is, how it possible to use const a few times in order to create elements, why it doesn't cause an error? In addition I want to ask, How can I manipulate those element: Let's say I have created few li elements, if for example I want to change the color of one of them to blue, How can I do that? When I write the variables names in the console I get this:

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


Here is the portion of my code that is rather bothersome:  \begin{center}      \begin{matrix}       E_1  \\       E_2      \end{matrix}      \begin{bmatrix}        1 & h & 2 \\      -5 & 15 & -12      \end{bmatrix}  \end{center}   And the result is    How do I go about getting the E_1 E_2 column to the left of the bmatrix?

I'm new to latex and all of my matrices seem to be created on new lines, I can't seem to put them side by side.  Here is what I am doing to make a matrix (with the 2d identity matrix as an example):  \[ \left( \begin{array}{cc} 1 & 0 \\ 0 & 1 \end{array} \right) \]   Am I making it wrong?  How can I place a second matrix directly beside this, as you would when doing matrix mathematics?  Thanks


I would like a verification of this proof:  Prove that $A\in M_n(\mathbb{C})$ is a nilpotent matrix if and only if $0$ is its only eigenvalue.    ($\Rightarrow$): if $A$ is nilpotent, then there's a index $k \le n$ such that $A^k = 0$. Let $\lambda$ be an eigenvalue of $A$. Since $Ax = \lambda x$, $A^kx = \lambda^k x = 0$, so $\lambda^k x = 0 \Rightarrow \lambda = 0$.  ($\Leftarrow$): argue for the sake of contradition that $0$ is the only eigenvalue of $A$ but $A$ is not nilpotent. Then $A \ne 0, A^2 \ne 0, \dots, A^n \ne 0$. Since $Ax = \lambda x$ with $x \ne 0$, $Ax = 0, A^2x = 0, \dots, A^nx = 0$. A contradition.  But something feels off about this, I'm not sure if this is correct.

I need to prove that:      if a linear operator $\phi : V \rightarrow V$ on a vector space is nilpotent, then its only eigenvalue is $0$.   I know how to prove that this for a nilpotent matrix, but I'm not sure in the case of an operator. How would I be able to relate $\phi$ to a matrix?  Note: A nilpotent operator $\phi$ has been defined as an operator that satisfies $\phi^{n} = 0$ for some $n \geq 1$.


I have created a Boolean method called trainer() inside the class Trainer which extends the abstract class Employees(). This method returns true if the Employee inside the list is a trainer and then it prints it. But when I execute the program there seems to be an exception with the Boolean method trainer. As for the ItemEmployees this is a class which expands a class called Item().   If needed I can provide both their codes. But I do not think the problem is in those classes.  The following is written within the main class:  Node firstnode = list.getFirst();  ItemEmployees t = (ItemEmployees) firstnode.getValue();  for(Node tmp=firstnode; tmp!=null; tmp=tmp.getNext()) {         if(tmp.getValue()!=null)          {                 Employees e = t.keye();                 if( e.trainer() )                 {                         e.print();                 }         } }   Now this is inside the Trainer() class:  public boolean trainer() {     return true; }   Exception     Exception in thread "main" java.lang.NullPointerException at MainClass.main(MainClass.java:348)   Line 348 is  if( e.trainer() )

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?


I place a spoon in my cup of (dolce gusto lungo) coffee and tap the bottom of the cup with my spoon.  It emits a certain (fixed) frequency.  However, if I stir the coffee (but not so fast that the surface of the coffee has any appreciable dip in the centre) and repeat the tapping in the centre with the spoon the frequency sounds lower initially but rises as the coffee stops rotating.  Curiously it appears to continue rising for a brief period after the coffee appears to have stopped rotating in the cup. What’s happening?  Is it related to the fact that if I stir the coffee fast enough then all the “froth” on the top of the coffee disappears (subsumed into the coffee?), but reappears as the rotation slows down. Other than stirring the coffee nothing is being added.

If a hot beverage in a cup gets stirred, the sound of the spoon changes. You can easily hear this if you repeatedly cling the spoon to the cup ground after stirring. The cling sound will raise in tune for quite a long time.  This even happens if the fluid motion is (almost) stopped after stirring, eg. by using the spoon to do so.  What is the reason for this effect? Why it last so long after stirring?


Pratt is given a fair die. He repeatedly  throw the die until he get at least each number (1 to 6).   Define the random variable $X$ to be the total number of trials that  pratt throws the die. or  How many times he has to throw a die so that each side of the die appears at least once.  Determine the expected value $E(X)$.

What is the average number of times it would it take to roll a fair 6-sided die and get all numbers on the die?  The order in which the numbers appear does not matter.  I had this questions explained to me by a professor (not math professor), but it was not clear in the explanation.  We were given the answer $(1-(\frac56)^n)^6 = .5$ or $n = 12.152$  Can someone please explain this to me, possibly with a link to a general topic?


I have a 13' MBP 2012 (non Retina). The problem is that left Option and Shift keys are not working with some combinations.  For example Shift Option Command → would not select any text. I can't do a screenshot as well (Command Shift 3/4).   The problem is with a left side only. The right one works great. Also, if I'm using an external keyboard on it left side is working fine.   The keys work fine with a simple combination (Shift Enter) or Option something. That issue really put me in stuck, because it's so inconstant.  Does anyone face the same issue? As I can remember that behavior appears after I tried to re-assign those keys in Windows Bootcamp (maybe it's just an accident that happened at the same time and it's not actually related). From that time I changed the hard-drive an installed a clean version of latest macOS. The problem still persist.   Any ideas what to do? I don't really want to give it to local services because its price right now is about $400 but they asking $120 for a diagnosis. There are no Apple stores in my or near-by cities.

This is an attempt to write a canonical QA for this issue, as per the Meta post:   I expect it to be periodically edited with the goal of becoming a comprehensive information resource.  I have a MacBook Pro that has a key(Shift, Return,   Command, P, etc.) that doesn’t respond when pressed or is stuck in the down position.    It's possible that my favorite beverage was spilled (or some other liquid damage).  It's also possible that I have no idea what happened.  It was working yesterday and suddenly today it's no longer working.  Is there any way to bypass or remap the key?  Can I  have the system ignore it completely?  (This question can also apply to external USB keyboards or the Bluetooth keyboards)


Find the order of $8/9, 14/5,48/28$ in the additive group of $\mathbb{Q}/\mathbb{Z}$    JUNK  Guessing asking for $8/9 * k = 0 $ (being a whole integer) for smallest integer so for this one is 9 . another guess would be the smallest element of $Q/Z$ being something like $9/8$  $14/5$ would be 5  $48/28=12/7$ would be 7?

Consider the quotient group $\mathbb{Q}/\mathbb{Z}$ of the additive group of rational numbers. Then how to find the order of the element $2/3 + \mathbb{Z} $ in $\mathbb{Q}/\mathbb{Z}$.


In X-Men: DoFP a significant alteration of the timeline is occurred. For a moment let's ignore that alteration. We are in 1973 and Professor X keeps taking his medication for the next few years in order for him to walk -which has the side effect of losing his mental powers. How Xavier ends up in the '80s, when we see him in the beginning of X-Men 3 both walking and also having his mutant powers? Is that a continuity error or is it explained somehow? I know that Singer doesn't like the events of X-Men 3, therefore he acknowledges what happened in that movie in X-Men DoFP (for instance, Cyclops is absent from the future scenes because he was killed in X3).  Note to duplicate report: This question is trying to explain why Professor X is seen walking and having his mental powers at the beginning of X-Men 3 (early '80s), while in X-Men DoFP it is explicitly mentioned that the treatment for his spine has affected his powers. The linked question, though, is trying to explain why Xavier walks in early '80s after being shot from Magneto at the end of X-Men: First Class, ignoring the events of DoFP.

At the end of First Class, Xavier is paralysed, and him and Magneto split paths. However at the beginning of Last Stand, it flashes back 20 years, and you see the grown up Xavier and Magneto, friends, talking to a young Jean Gray.  Did Xavier get the use of his legs back and then lose it again?  Or is this just a continuity error?


My blog has a content div with an id of #content. When I select it, e.g. with Firebug it outlines the full height of the div, with all its padding and margins at the top and the bottom.   jQuery height() returns only the inner height of the element itself.  How can I query the full height of the element? If there are other elements with a lot padding and margin in them I want all of it added up and as one value.  Which method should i use?

As in the subject, how can one get the total width of an element, including its border and padding, using jQuery?  I've got the jQuery dimensions plugin, and running .width() on my 760px-wide, 10px padding DIV returns 760.  Perhaps I'm doing something wrong, but if my element manifests itself as 780 pixels wide and Firebug tells me that there's 10px padding on it, but calling .width() only gives 760, I'd be hard pressed to see how.  Thanks for any suggestions.


My variable value in path is as follows  C:\ProgramData\Oracle\Java\javapath;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Skype\Phone\;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;%PYTHON_HOME%\;%PYTHON_HOME%\Scripts;C:\SQLite   When I type echo %Path% on command prompt, I get below output  PS C:\Users\Arun> echo %Path% %Path%   Why is this?

In Windows 7, when I start the Command prompt, is there any command to display the contents of an environment variable (such as the JAVA_HOME or PATH variables)?  I have tried with echo $PATH, echo PATH and $PATH but none of these work.


Similar questions have been asked, but I've found them to be of no help. When I try to reference an equation in texstudio, all I get is ?? An example of code I have inserted which does this (I have taken this from Wikipedia) is:  \begin{equation} \label{eq:solve} x^2 - 5 x + 6 = 0 \end{equation}  \begin{equation} x_1 = \frac{5 + \sqrt{25 - 4 \times 6}}{2} = 3 \end{equation}  \begin{equation} x_2 = \frac{5 - \sqrt{25 - 4 \times 6}}{2} = 2 \end{equation}  and so we have solved equation ~\ref{eq:solve}   Instead of it displaying a number I just get ??, and yes I've compiled more than once.  For completeness I'll include the beginning of my code:  \documentclass{book} \usepackage{amsmath} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{MnSymbol} \usepackage[thmmarks]{ntheorem} \theoremheaderfont{\bfseries} \theorembodyfont{\normalfont} \theoremseparator{:} \theoremsymbol{$\square$} \newtheorem*{proof}{Proof}[chapter] \newtheorem{prop}{Proposition}[chapter] \newtheorem{corollary}{Corollary}[chapter] \newtheorem{theorem}{Theorem}[chapter] \newtheorem{lemma}{Lemma} \numberwithin{theorem}{section} \numberwithin{prop}{section} \numberwithin{corollary}{section} \numberwithin{lemma}{section}

I have a strange problem with cross-referencing my equations: no matter how often I run pdflatex they stay undefined. Other references do get resolved.  Is there something wrong with the way I label my equation? Pdflatex does not complain about it (other than reporting it is undefined when trying to reference it).  Edit: As requested below I made a minimal working example. From this I learned that the problem seems to be a conflict between the amsmath and ntheorem packages. Not including one of these solves the problem.  Consider for example the following example:  \documentclass{article} \usepackage{amsmath} \usepackage[thmmarks]{ntheorem}  \begin{document}  \section{My Section} \label{sec:MySection}  \begin{equation} \label{eq:MyEquation} a = b \end{equation}  Reference my section \ref{sec:MySection}. Reference my equation \ref{eq:MyEquation}.  \end{document}   Which is rendered as:


Email from TLScontact states that decision has been made and sent directly to my email however, I haven't seen the email nor received the passport.   Any one who has ever received a similar email and how they retrieved the UKVI email? Dear Customer, TLScontact was notified by UKVI that a decision related to your visa application has been made and communicated directly to you by email. As soon as your passport is ready to be returned, you will receive another email about the collection or the delivery procedure. You can track the progress of your visa application by connecting to your account or by using our Track My Application app.

I received the following email this morning. Does it mean that my visa has been granted?  UK Visas & Immigration has now assessed your UK visa application and made a decision. Your documents and the decision will be sent back to either the UK Visa Application Centre where you applied, where we will contact you by email over the next few days to collect them, or if you are using the courier return service, will be sent directly back to the address provided. Please note that TLScontact does not know the outcome of the assessment and has played no role in the decision-making process. Kind regards, TLScontact UK VIsas & Immigration


I am currently living in Geneva. I lost my Indian passport with US visa and I am wondering if I should apply for the Visa from Bern or from India. I contacted the Indian consulate and they told me they will get me a new passport in a couple of weeks. Has any body been in this situation before? How did it go?

I hold an EU Blue Card and an Indian Passport and have submitted a paper to a conference in the USA due to occur in September 2019. The Blue Card will expire in August 2019 but have already obtained an extension for the same.  In order to present the paper in the conference I need to apply for a B1/B2 visa for the USA and not sure if I may be allowed to apply for one in Germany since I am not a German Citizen.  Are there any specific documents that I might need in order to apply for the B1/B2 Visa since I am not a citizen of the country where I am actually applying?


With tabular or tabularx environment, when dealing with numbers , percentages and other math symbols per se, do we need to use the math mode ( $$ for instance ) with every number/symbol.   Is there an option to enable math mode by default in tabular or tabularx ?

\begin{tabular}{|l|l|l|} \hline Column A & Column B \\  \begin{math} x & y \\ \end{math}  \end{tabular}   This won't let me compile and gives a lot of errors, how do I enable math mode in a table without using $ on everything?


How to undelete photos in a Samsung galaxy S4 active? I have deleted a folder on the phone with pictures in it and I would really like get them back. Not on SD card but in the phones memory.

I just deleted a file on my Nexus S that I really need back. (It was actually part of an app using a sqlite database that did a drop table when upgrading to a new version.)  Presumably I need to root the phone first (which I hear is easy on Nexus phones) but am I in a catch-22 here? Namely, does rooting the phone mean wiping/overwriting the partition where the data lives?  If not, what do you recommend for data recovery tools? Presumably the file was just unlinked and not actively overwritten (per usual when "deleting" a file) so technically the data must be there...


Does that mean that "I don't have any time" or "I have time" because there are two no's there?

This song by The Rolling Stones, "(I Can't Get No) Satisfaction". As a non-native speaker, I always wondered what's the exact meaning of this phrase?   Is it "I'm not getting any satisfaction" (this seems to be the most widely met translation; double negation used where single negation should have been used). Or is it "I want my satisfaction, I cannot leave without getting some" (makes much more sense to me).   Or is it something else? I've always had troubles understanding double negation as applied to English. First I was taught it's a mistake to use double negation at all, and then I see it everywhere.


I am stuck on the following question which I came across in a recent exam paper:  Let $f \colon [\pi,2 \pi] \to \Bbb R^2$ be the function $f(t)=(\cos t,\sin t)$.Then which of the following are necessarily correct? The options are:  There exists $t_0 \in [\pi,2\pi]$ such that $f'(t_0)=\frac{f(2 \pi)-f(\pi)}{\pi}$  There exists no $t_0 \in [\pi,2\pi]$ such  that $f'(t_0)=\frac{f(2 \pi)-f(\pi)}{\pi}$  There exists $t_0 \in [\pi,2\pi]$ such that $||f(2 \pi)-f(\pi)|| \le \pi ||f'(t_0)||$  $f'(t)=(-\sin t,\cos t) \,\,\forall t \in [\pi,2\pi]$.    MY ATTEMPT: Clearly option 4 is correct but I am not sure how to prove/disprove for other options. Looking at options 1,2,3 I think mean value theorem has a role to play.  Can someone explain me with some details. My edit:  Option 3 appears to be true since $||f(2 \pi)-f(\pi)||=||(1,0)-(-1,0)||=||(2,0)||=2$ and $\pi ||f'(t_0)||=\pi \,\,\text{since}\, ||f'(t)||=||(- \sin t,\cos t)||=1$ and so $||f(2 \pi)-f(\pi)|| \le \pi ||f'(t_0)||$ is true. Option 1 makes no sense after putting the values of $\pi, 2\pi$ in $f$. So option 2 appears to be correct. Am I going in the right direction? Is there any other elegant way of tackling this problem?

$f:I=[\pi,2\pi]\to \mathbb{R}^2$ be given by $f(t)=(\cos t,\sin t)$  which of the following are necessarily correct?  $1$. $\exists t_0\in I$ such that $f'(t_0)=\frac{1}{\pi}(f(2\pi)-f(\pi))$  $2$. $\nexists t_0\in I$ such that $f'(t_0)=\frac{1}{\pi}(f(2\pi)-f(\pi))$  $3$.$\exists t_0\in I$ such that $\pi||f'(t_0)||\ge ||(f(2\pi)-f(\pi)||$  $4$. $f'(t)=(-\sin t,\cos t)\forall t$  $4$ is clearly true, $1$ is true by Mean Value Theorem as $f$  satisfies all the conditions of MVT? have no idea of $2$ and $3$, Thank you for help


Is it possible to use the Kruskal-Wallis test for two factors and their interaction (i.e., two way ANOVA: Y~a*b)? And which post-hoc test is possible to use after the Kruskal-Wallis test?

Hi I am trying to find the non-parametric equivalent of a two-way ANOVA (3x4 design) which is capable of including interactions. From my reading in Zar 1984 "Biostatistical analysis" this is possible using a method put forth in Scheirer, Ray, and Hare (1976), however, according to other posts online it was inferred that this method is no longer appropriate (if it ever was).  Does anyone know what method would be appropriate for doing so, and if so the corresponding functions in R or Stata?


This was posted in another question and below is the link.      Prove Theorem 2.5(iii), namely, that if $f$   is continuous at $a$ and $λ$ is a scalar, then $λ⋅f$ is continuous at $a$ i.e. $$0<|x−a|<δ⇒|λf(x)−λf(a)|<\varepsilon$$    Here $|λf(x)−λf(a)|<\varepsilon$ is not equivalent to $|λf(x)−λf(a)|<\frac{\varepsilon}{λ}$ but rather to $|λf(x)−λf(a)|<\frac{\varepsilon}{|λ|}$  My question is regarding the last inequality, shouldn't this be $|λf(x)−λf(a)|<\varepsilon$ instead?

I'm studying some proofs in a book from the library  and  unlike my own book, it doesn't prove by showing that a certain expression is striclty less than $\varepsilon$ (given an  appropiate $\delta$ and $\vert x-a\vert < \delta$, etc). Instead, it shows that it's less than some expression involving $\varepsilon$.   E.g. Given $\varepsilon > 0$, we can pick a $\delta > 0$ so $|f(x) - g(a)| <  \text{insert stuff} < k \cdot \varepsilon$ when $|x-a| < \delta$, and thus $f(x) - g(a) \to 0 $ when $x \rightarrow a$.  How does this make sense formally? (Intuitively, I am convinced.)  I don't have much experience with $\varepsilon$-$\delta$ -proofs, so I might be missing something obvious.


Verify that $S=\{0\}\cup\bigcup_\limits{i=1}^{\infty}\{\frac{1}{n}\}$ is compact subset of $\mathbb{R}$ while $\bigcup_\limits{i=1}^{\infty}\{\frac{1}{n}\}$ is not.  If I take the sequences $\{\frac{1}{i}:i\in\mathbb{N}\}$ there is no convergent subsequnce once $\{0\}\notin \bigcup_\limits{i=1}^{\infty}\{\frac{1}{n}\}$ . So $\bigcup_\limits{i=1}^{\infty}\{\frac{1}{n}\}$ is not compact. However when I examine $S=\{0\}\cup\bigcup_\limits{i=1}^{\infty}\{\frac{1}{n}\}$. I do not know how can I address all the coverings in order to prove it is compact. Questions: Is my proof right insofar? How should I prove $S$ is not compact? What is the strategy for that sort of cases? Thanks in advance!

Prove that $ S=\{0\}\cup\left(\bigcup_{n=0}^{\infty} \{\frac{1}{n}\}\right)$ is a compact set in $\mathbb{R}$, but $\bigcup_{n=0}^{\infty} \{\frac{1}{n}\}$ is not a compact set.   (Can we use definition of compact set for this problem? )


About a year ago "Files" and "File Manager" started to act very strangely and all my files were lost, despite an extensive search. Two days later I lost all my data and files from my SATA hard-drive. Luckily I had a backup, but "Files" continued to lose everything every time I put removable media into the USB slots.  Frustrated with "Files" and "File manager" I installed "Thunar" which was an instant success. However "Files" is still set as the default manager for removable media and Rubbish Bin.  Today "Files" moved the contents of my terrabyte SATA drive into the Rubbish Bin and changed the permissions, which prevented me from restoring the contents back onto the drive with "Thunar". In the end I had to copy the folders onto my desktop, rename them and put them back that way.  I want to remove "Files" and "File Manager" but they cannot be un-installed in either "Software Centre" or the Dashboard. I cannot make "Thunar" open the removable media or the rubbish bin as "Files" must be the default for these operations. Is there any way of using terminal to remove these apps as they seem to be standard as part of the Ubuntu package

I would like to set Thunar as my default file manager in 15.04. Now, I realize that this question is very similar to , but I have tried , why I even tried rebooting after I completed his suggestion but still Nautilus is used as my default File Manager. I even tried the , Midnight Commander and Manual solutions recommended on the Community Help Wiki. Not one changed Thunar to my default file manager.   I was curious as to whether exo could change my default file manager at all, say to dolphin (as I also saw  and ) but that also failed. Something tells me that this issue affects not just me but other users too, specifically 15.04 users, as Ubuntuuser reported in the comments that he could not set dolphin as his default file manager via exo either.   If you would like to know how I am checking whether these file managers are set to default, well I open folders on my desktop by double-clicking them to see whether they're opened in these alternative file managers or not and as a second test I also try to save files in Chrome to see whether the file manager window that pops up is the one I want.   If relevant I am running Unity as my Desktop Environment.


I have recently upgraded to Gnome 3.16.2 (not sure what version I hade before) and then my MMOD Panel extension was no longer compatible. I only get the message "Does not support shell version".   The same goes for the Panel Settings extension. This didn't work on my previous version either.    I absolutely loved having the top panel at the bottom and was wondering if there was a setting or extension that would fix this in my version. I have tried searching google with no luck.  The Taskbar extension embedded in Tweak Tool has only the option "add bottom panel", which does not move the top, but simply adds one on the bottom.

Is there a way to move the top panel to the bottom in Gnome 3? It is very annoying to have this panel at the top, because then I have to aim for the close button when I want to close a window. When the panel is at the bottom, I can simply throw the mouse pointer to the corner. Big usability issue.


I am doing a LaTex document in VS Code with the extension LaTex Workshop, but when I build the pdf sometimes it delays 30 seconds, or even more, which feel like an eternity. Is it the average time or is there a way to speed it up?

Usually I don't mind about LaTeX's compilation speed, because a paper of less than 20 pages is compiled rather fast.  However, I am working on a large document - A report with more than 80 pages.  Compilation times are starting to slow me down.  I saw the couple of answers here on this topic, but most of my graphics are external and I don't use Tikz.  As a matter of fact, I'm not sure what's slowing the compilation down, other than the amount of text and required layout.   What's your best speeding-tex-up trick, other than externalizing graphics and pre-compiling the preamble? How can I know what's slowing TeX down?


I'm stuck on the following exercise from Herstein's "Topics in Algebra":  "Show that if $(a,n)=1$ then you can find $[b]\in J_n$ such that $[a][b]=1$"  (note: $[a]$ is the congruence class (mod $n$) of $a$, and $J_n$ is the set of congruence classes mod $n$)  I've been thinking about using the property $(a,n)=1\Rightarrow \exists h,k\in\mathbb{Z}$ such that $ha+kn=1$ and also the Euclidean algorithm by writing $a=qn+b$ $0\leq b<a$ (since $J_n=\{[0],...[n-1]\})$ but I haven't been able to come up with a proof.  So, I would appreciate any comment/hint about how to prove this fact.  Best regards,  lorenzo

I need help with this:  If a is an element of $\mathbb Z_n$ and $\gcd(a,n) > 1$ , then a is not invertible.   First you show that if $a$ is an element of $\mathbb Z_n$ and $\gcd(a,n)>1$, then there  is an element $b$ of $\mathbb Z_n$ and ($b$ is not equal to the zero element) from which $ab = 0$.   The second part I cant get. i.e. show if $b$ is not the zero element  and $ab=0$ then $a$ is not invertible.


Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I use this charset because it is the most complete one  <meta charset="UTF-8" />   but actually I still see the character � for example for the word menù  Why?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


When I click start,some choices will be displayed.  I would like to select each choice by getElementById is it possible?  How can I change my work to achieve it ?  Thanks    document.getElementById("start").addEventListener('click',function(){   html=" ";   for (let i=1;i<=4; i++){     html+= "<button id='choice'>"+"choice"+i+"</button>
";   }   document.querySelector('.btn').innerHTML = html; });  document.getElementById("choice").addEventListener('click',function(){   console.log(this); });
<button id="start">start</button>

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I read some of the answers on    But then I thought of places like Mount Everest and its summit. Why is it freezing and cold? If hot air rises shouldn't it be like a desert up there?

Why there is always cold at high altitudes. e.g. at peak of mountains. Also as we go high from sea level, temperature starts decreasing. Why is it?


What would you call the line in a fraction? It is a horizontal line that is between the numerator and the denominator.    Suggestions:   vinculum solidus fraction line fraction bar fraction stroke *shilling stroke   I admit that sometimes it can have a shape of a slash, so it doesn't have to be horizontal.

What is the name of the horizontal division line? Is there a name for it other than "division line?


I've built a Windows service as "Any CPU". However, when I run it on my 64 bit machine it runs in 32 bit. How can I fix it? I'm using .NET and C#, and my operating system is Windows 2008 R2.  If I build it in x64 it correctly loads in 64 bit mode. However, "Any Cpu" -- which is what I want -- loads in 32 bit, even though the machine it's running on perfectly supports 64 bit.  EDIT to add more information based on feedback  We do have third party tools as well as reference a c++ managed assembly. These may or may not be built for any CPU. In fact i know that the c++ managed assembly is only built for x86. However, the odd things is that if I specifically specify x64 the process will start up and work in x64. If the framework were to attempt to load the c++ managed assembly it would fail. I don't mind this, because in the code, we do not load the 32bit managed ++ assembly if we're running in 64 bit mode. Could it be that the build figures that since there is a 32 bit assembly in here it should mark the launching process (in this case a windows service assembly) as x86?

I have some confusion related to the .NET platform build options in Visual Studio 2008.  What is the "Any CPU" compilation target, and what sort of files does it generate? I examined the output executable of this "Any CPU" build and found that they are the x86 executables (who would not see that coming!). So, is there any difference between targeting executable to x86 vs. "Any CPU"?  Another thing that I noticed, is that managed C++ projects do not have this platform as an option. Why is that? Does that mean that my suspicion about "Any CPU" executables being plain 32-bit ones is right?


Let $f:\mathbb{R}\to \mathbb{R}$ be a continuous function such that $f^3(x)=f\circ f\circ f(x)=x$ for all $x$.  How can I prove $f$ is the identity function?

If $ f: \mathbb{R} \to \mathbb{R} $ is continuous, and $\forall x \in \mathbb{R} :\;(f \circ f \circ f)(x) = x  $, show that $ f(x) = x $.  The condition that $f$ is continuous on $\mathbb{R}$ is crucial for the proof. I can find functions such as $\displaystyle\frac{x-3}{x+1}$ that satisfies  $ (f \circ f \circ f)(x) = x $. I have tried to negate the conclusion to see if there's a contradiction, but got stuck.


Among various kind of sports / kinds of sports / kinds of sport, I like soccer the best.   Which one is correct? Is there any rule implying that one of them has to be singular between 'kind' and 'sports' if the other one is plural and vice versa?

A. These kinds of problem are to be avoided. B. These kind of problems are to be avoided.  Are both A and B grammatical? If not, why not? If so, after having noticed the parallelism between A and C, and between B and D, could we say that C and D are "standard" English, too?  C. These kinds of problem are ones to avoid. D. These kind of problems are ones to avoid.


Which one is correct ?         "I don't know what was that"      or        "I don't know what that was"

What is the difference between:        "How it works?"      and        "How does it work?"


I have been learning before about threading but in C++. Now for the first time I'm trying to configure this code to work corectly but without CheckIllegal ... = false.  I have been trying to put delegates in there and lots of other stuff but the I getting the same problem. Both threads are entering the methof WriteInLog and I can't really see how to make this work.  Anyone has an idea and explanation?  namespace viseNitniRad {     public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();           }         private int firstNum = 0;         private int secondNum = 0;         public Thread firstThread;         public Thread secondThread;          public  void WriteInLog(string message)         {             lock (textBox3)             {                 textBox3.Text += message + Environment.NewLine;             }         }          private void CheckInput()         {             int pom = 0;             firstNum = int.Parse(textBox1.Text);             secondNum = int.Parse(textBox2.Text);             if (firstNum > secondNum) {                 pom = secondNum;                 secondNum = firstNum;                 firstNum = pom; }              WriteInLog("Prvi broj: " + firstNum.ToString());             WriteInLog("Drugi broj: " + secondNum.ToString());         }           private void button1_Click(object sender, EventArgs e)         {             CheckInput();          }          public delegate void ThreadSum();         public delegate void ThreadUmn();         public void Threadsumm()         {             int suma = 0;             for (int i = firstNum; i < secondNum; i++)                 suma += i;             WriteInLog("Suma= " + suma.ToString() + " kraj: " + DateTime.Now.ToString());          }          public  void ThreadUmno()         {             int umnozak = 1;             for (int i = firstNum; i < secondNum; i++)                 umnozak*= i;             WriteInLog("Umnozak= " + umnozak.ToString() + " kraj: " + DateTime.Now.ToString());         }          private void button2_Click(object sender, EventArgs e)         {             WriteInLog("Pocetak svih izracuna u: " + DateTime.Now.ToString());              firstThread = new Thread(new ThreadStart(Threadsumm));           secondThread = new Thread(new ThreadStart(ThreadUmno));               firstThread.Start();             secondThread.Start();           }     } }

I have a scenario. (Windows Forms, C#, .NET)   There is a main form which hosts some user control. The user control does some heavy data operation, such that if I directly call the UserControl_Load method the UI become nonresponsive for the duration for load method execution. To overcome this I load data on different thread (trying to change existing code as little as I can)   I used a background worker thread which will be loading the data and when done will notify the application that it has done its work.   Now came a real problem. All the UI (main form and its child usercontrols) was created on the primary main thread. In the LOAD method of the usercontrol I'm fetching data based on the values of some control (like textbox) on userControl.    The pseudocode would look like this:  CODE 1  UserContrl1_LoadDataMethod() {     if (textbox1.text == "MyName") // This gives exception     {         //Load data corresponding to "MyName".         //Populate a globale variable List<string> which will be binded to grid at some later stage.     } }   The Exception it gave was     Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on.   To know more about this I did some googling and a suggestion came up like using the following code  CODE 2  UserContrl1_LoadDataMethod() {     if (InvokeRequired) // Line #1     {         this.Invoke(new MethodInvoker(UserContrl1_LoadDataMethod));         return;     }      if (textbox1.text == "MyName") // Now it wont give an exception     {     //Load data correspondin to "MyName"         //Populate a globale variable List<string> which will be binded to grid at some later stage     } }   BUT BUT BUT... it seems I'm back to square one. The Application again  become nonresponsive. It seems to be due to the execution of line #1 if condition. The loading task is again done by the parent thread and not the third that I spawned.  I don't know whether I perceived this right or wrong. I'm new to threading.  How do I resolve this and also what is the effect of execution of Line#1 if block?  The situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread.   So only accessing the value so that the corresponding data can be fetched from the database.


When I am trying to edit some files I am getting this warning. How can I resolve this error.  (gedit:5596): IBUS-WARNING **: The owner of /home/user/.config/ibus/bus is not root!

Whenever I try to run a sudo gedit command , my terminal puts out:     (gedit:7549): IBUS-WARNING **: The owner of /home/jared/.config/ibus/bus is not root!   How do I get out of this situation?


In my physics material it says the gravitational force can be considered to be applied to the centre of mass of a body only in the following cases: 1.The effective gravitational field is homogeneous 2.The body has a spherically symmetric mass distribution 3.The effective gravity field is proportional to the radius vector Condition 1 makes perfect sense to me , If the centre of gravity is not at the centre of mass than obviously gravity can not be considered to act on it . Why are the other two conditions required ?

"The centre of mass of a system of particles is the point that moves as though (1) all of the system's mass were concentrated there and (2) all external forces were applied there." (Resnick et al, p.215) "The gravitational force on a body effectively acts at a single point, called the centre of gravity of the body." (Resnick et al, p.330) According to these concepts: If we have a body large enough that we could not assume that the centre of mass and the centre of gravity doesn't coincide. Then, by definition of the centre of gravity, the gravitational force does not act on the centre of mass. This means that we have an external force which we can't consider to be acting on the centre of mass. Q (1)-Does the centre of mass still move as if the gravitational force were applied there? Q (2)-Aren't this concepts the best definitions of the center of mass and centre of gravity? Q (3)-What would be the axis rotation if I apply a force to one corner of this body? Source: Fundamentals os physics / Robert Resnick, David Halliday, Robert Resnick - 10th edition.


Am I missing something basic in Java Math calculations for float numbers ? I can use Math function round(), However I want accurate value 6.4 as the input given is simple and doesn't have many values after the decimal point.   System.out.println(1.8f+1.0f+1.9f+1.7f); // Expected 6.4 but actual is 6.3999999999999995 how ?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Find all continuous $f :[0,1]\to \mathbb R$ such that $\forall x\in [0,1], f(x)+f(x^2)=x$   I suspect there are none.  I made little progress so far, but it's worth noticing that $f(0)=0$ and $\displaystyle f(x)+\lim_{n\to\infty}\left((-1)^n\sum_0^{n-1}(-1)^{k+1}x^{2^k}\right)=0$

Prove that there is no continuous functions $f:[0,1]\to R$, such that   $$ f(x)+f(x^2)=x. $$   My try. Assume that there is a continuous function with this property. Thus, for any $n\ge 1$ and all $x\in [0,1]$, \begin{align*} f(x)&=x-f(x^2)=x-\big(x^2-f(x^4)\big)=x-x^2+\big(x^4-f(x^8)\big)=\cdots\\ &=x-x^2+x^4-\cdots+(-1)^n\left(x^{2^n}-f\big(x^{2^{n+1}}\big)\right) \end{align*}  since $f(0)=0$ and $\displaystyle\lim_{n\to \infty}x^{2^{n+1}}=0$ for any $x\in(0,1)$,it follows by the continuity of $f$ that $\displaystyle\lim_{n\to \infty}f\big(x^{2^{n+1}}\big)=0$, hence $$f(x)=x-x^2+x^4-x^8+\cdots+(-1)^nx^{2^n}+\cdots$$ for any $x\in (0,1)$  Why do I have prove that there is exists such a continuous functions $f$? Maybe  my example is wrong? Why?  if my   method is wrong,then How prove this problem ? Thank you.


At the end of the 1977 film "Star Wars: A New Hope" Luke, Han, and Chewie are presented with  medals in front of a large crowd by Princess Leia.  What were the names of the medals?  (Medal of Valor, etc.?)  Did they have anything written in them?

What award/medal is this -  I have been searching  to try and find what medal this is, but i have not found it, does anyone know what this medal/award was and why it would be given (eg- bravery, serving in the battle of Yavin)?


I recently rendered a project i was working on and found that the main object was missing in the final render. I checked older versions of the file and it was all the same. What could it be?  the render is on the right.  this is the most recent state. There are some pyramids on top. I wondered if it has something to do with textures i added, but i removed them and nothing changed.  this is an older version, before i tinkered with textures...

Why is the selected object displaying in the 3D view, but not rendering?  In object mode, it shows up:   However, it does not show up in render mode:   Why is this so and what causes it to hide in render mode?


Here is a MWE:  \documentclass{minimal} \usepackage{xltxtra} \usepackage{fontspec} \setmainfont[Ligatures=TeX]{Adobe Garamond Pro} \makeatletter \g@addto@macro\normalsize{   \setlength{\intextsep}{0.8cm}   \setlength\abovedisplayskip{5pt}   \setlength\belowdisplayskip{5pt}   \setlength\abovedisplayshortskip{5pt}   \setlength\belowdisplayshortskip{5pt} } \makeatother \begin{document} Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor\footnote{This is a footnote.} incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. \end{document}   When I comment \setmainfont[Ligatures=TeX]{Adobe Garamond Pro} (ideally required since it's the font that I want) I get this output:    When I comment the \makeatletter \makeatother block (ideally required because that's the spacing that I want for equations in the rest of the document), I get this output:     When I comment nothing, I get this output with the extra blank space:    Does someone know what is wrong here and how I can overcome this issue? Many thanks,

I see that the code in many packages and examples contains percent signs % at the end of (many) lines. What are they used for? Do they affect the parsing of those lines?


It's a pretty common occurrence. My code doesn't work. Why? I have no idea. So I call over a coworker to look at it, but the instant he looks at the code it is magically working.  Another situation -- my mother in law's DVD player is not working so she calls and asks for me to fix it. She promises that if I fix it she'll cook me a delicious roast for dinner. I drive four hours to her home and turn on the TV and the DVD is playing.  Does anyone know if there is a well known adage or epigram that goes along with these occurrences of something not working until a third party looks at whatever is broken?  EDIT - I'm going to go out on a limb and say that all of the answers to the previous question don't actually answer this. All of the terms are either personal terms that are used in a small group of people e.g. proximity fix, or are inaccurate e.g. intermittent fault.  Intermittent Fault would explain if it happens occasionally without any explanation. In my situation the problem never arises again after someone else looks at it.  Repair Phobia would imply that the individual is afraid of actually fixing it, which I'm not afraid of when I'm fixing my own code.  See also this question that doesn't give an already existing or well known epigraph or adage. :

This seems to be a common enough occurrence that it would merit its own phrase. I imagine it might be some sort of subset of Murphy's Law. But it's specific enough that Murphy's Law doesn't quite address it.  Do you know when you are banging your head against a wall for hours trying to fix something? And then when you finally give up and try to get someone else to come fix it (or even just look at it to see that it's broken), it's working perfectly as if nothing had ever happened? And at this point, you're just trying to convince the other person that it was broken in the first place.  It'd at least take some of the frustration out of the experience if you could both just laugh about <insert the phrase for it here>. But as it is now, I basically have to go through the whole paragraph above to say it, and at that point the joke is kind of lost.


I have some keywords  private static readonly string[] Keywords = {   "SELECT", "FROM", "WHERE", "GROUP", "HAVING", "ORDER", "LEFT", "RIGHT", JOIN", "INNER", "OUTER", "ASC", "DESC", "AND", "OR","IN", "BETWEEN", "BY", "NOT", "ON", "AS", "CASE", "WHEN", "ELSE" };   I want to uppercase these keywords in a string    string Query = "Select * fRom TableA"   This string should be converted to SELECT * FROM TableA  That is, Case will be ignored and keywords will be uppercased.  For this, I have written a function      public static string GetUppercaseKeyword(string sqlStr)     {         string sqlText = string.Empty;         int foundAt = 0;          foreach (var keyword in Keywords)         {             if (sqlStr.IndexOf(keyword, foundAt, StringComparison.CurrentCultureIgnoreCase) == -1)             {                 continue;             }              sqlStr = Replace(sqlStr, keyword, keyword.ToUpper(), StringComparison.OrdinalIgnoreCase);         }          return sqlStr;     }   and the replace function is    public static string Replace(string str, string old, string @new, StringComparison comparison)     {         @new = @new ?? "";         if (string.IsNullOrEmpty(str) || string.IsNullOrEmpty(old))             return str;         int foundAt = 0;         while ((foundAt = str.IndexOf(old, foundAt, StringComparison.CurrentCultureIgnoreCase)) != -1)         {             str = str.Remove(foundAt, old.Length).Insert(foundAt, @new);             foundAt += @new.Length;         }         return str;     }   The thing that happens here is, if a substring matches with the keywords, the method uppercase the substrings, as in Replace method I use IndexOf  For example, select * From OrderTable will output SELECT * FROM ORDERTable.  How can I solve the problem?  My other questions are, is there any easy way to implement it? Is there any existing algorithm for this type of purposes?

I need to search a string and replace all occurrences of %FirstName% and %PolicyAmount% with a value pulled from a database. The problem is the capitalization of FirstName varies. That prevents me from using the String.Replace() method. I've seen web pages on the subject that suggest  Regex.Replace(strInput, strToken, strReplaceWith, RegexOptions.IgnoreCase);   However for some reason when I try and replace %PolicyAmount% with $0, the replacement never takes place. I assume that it has something to do with the dollar sign being a reserved character in regex.   Is there another method I can use that doesn't involve sanitizing the input to deal with regex special characters?


The music in question is not exactly owned by the other individual either, as it's simply an arrangement of a game's soundtrack as a midi or music sheet.  Am I allowed to use these in my videogame? Should those persons be given credit or should it go to the original composers of the track in the original video game?   Should I ask for permission for the authors of the rearrange? What if the file and site list no author? What if it lists an author but I have no means to reach and ask?

Background: I'm making a retro style game for both fun, and an unofficial contest.   I have bought a song, song X. However, I then found notation for song X, and all the instruments. So basically, it's a program recreating song X in a sense.  I took the notation, and used another program to make it sound like a chiptune does (just for the fun of it, and it sounds good :P). However, I would like to use this in my game. It's non-commercial, but is this allowed? I would've said yes, because I'm not actually using the original, copyrighted song.  I think the main point is can I:   Use the music with no reference to the author Use the music with a reference, since it's non-profit. Not use the music at all since the melody and rhythm is copyright.


So I was looking at the work= force x distance equation and was just wondering if for example I normally do 100 dead lifts at 100 pounds.  Would I get the same calories burned if I did 50 dead lifts at 200 pounds.  According to the work formula I am doing the same amount of work.  If this is true how do you know our muscles use the same energy at double the weight and half the reps?  How can we prove that our muscles are burning the same energy with half the reps at double the weight.  Do we just accept it because it satisfies the work formula?

Am I correct to say that when a human lifts a dumbbell from, say, 2 feet off the ground to 6 feet off the ground, he will have increased the potential energy of the weight and thus will have burned calories to supply that energy increase?   Will two different people, Arnold Schwarzenegger in his prime and a scrawny kid for example, expend the same amount of calories moving the dumbbell from 2 feet straight up to 6 feet? Even though it's much easier for Arnold to lift it up, is he still burning the same number of calories as the scrawny kid?  If one lifts the weight up very slowly, isn't that going to expend more calories? When you prolong your exercise, but still do the same number of repetitions, you sweat a lot more and feel more tired, which seems to say that more calories are burned. But there's no time variable in the formula for potential energy (U = mgh). What other energy equation must we use then?


If I'm playing Brave New World multiplayer as part of a team it appears that, unlike science, our culture and tourism are not combined.  That means the best way for the team to win a culture victory is to give all the great artists to one player, let that player build all tourism benefiting wonders and basically concentrate entirely on that player's civ, which seems like it might not be much fun for the other player(s).  Have I understood this correctly?  Edit: I've just read the question that people have marked this as a duplicate of, sounds like it's even worse - everything I've said is true, plus you need to influence your partner too, yet you can't have open borders with them!  Sounds like this isn't a good way to go in multiplayer.

I'm playing a game with a friend where I'm doing my best to stack tourism. I've noticed that I'm still "exotic" to him and he has a TON of culture. I also cannot generate many tourism bonuses for him because "open borders" does not exist.  Do I have to become influential with my human ally (teammate) to win a culture/tourism victory? (more tourism than his total culture)  I cannot find the information on this anywhere.


This is more for a feature request. I would like to have queries at the same level as questions and answers in SE. I would like to be able to comment on them, vote them up and down, and notify the author if the query no longer works.

The tag wiki for  says:  The Data Explorer, located at data.stackexchange.com, allows you to create and run queries against copies of the databases of popular StackExchange sites to investigate trends or satisfy your curiosity. For questions about the ,   So there's a link to the FAQ, but it seems to imply that data.stackexchange.com is the place to ask questions about Data Explorer (I can't find any questions about DE there, though). By contrast,  says questions are asked here. Which one is it?


I use window management hotkeys constantly, think it's one of the best features of ubuntu. However, I have two problems when I plug in an external monitor. However I cannot send a window, with hotkeys, between monitors. I used to be able to do this on windows, and it was a really useful feature.

I have a laptop and a 27 inch monitor. I have Qt running on one monitor and Pycharm on the other. Is there a way to make a key combination to swap all the windows between both screens. The reason is that I want to program on the big screen only. I have already 4 workspaces and all of them are already used.  The output of xrandr:  Screen 0: minimum 320 x 200, current 3840 x 1080, maximum 32767 x 32767 eDP1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 344mm x 193mm    1920x1080      60.2*+   59.9      1680x1050      60.0     59.9      1600x1024      60.2      1400x1050      60.0      1280x1024      60.0      1440x900       59.9      1280x960       60.0      1360x768       59.8     60.0      1152x864       60.0      1024x768       60.0      800x600        60.3     56.2      640x480        59.9   HDMI1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 597mm x 336mm    1920x1080      60.0*+   50.0     59.9      1920x1080i     60.1     50.0     60.0      1600x1200      60.0      1680x1050      59.9      1280x1024      75.0     60.0      1440x900       59.9      1280x960       60.0      1366x768       59.8      1152x864       75.0      1280x720       60.0     50.0     59.9      1024x768       75.1     70.1     60.0      832x624        74.6      800x600        72.2     75.0     60.3     56.2      720x576        50.0      720x480        60.0     59.9      640x480        75.0     72.8     66.7     60.0     59.9      720x400        70.1   DP1 disconnected (normal left inverted right x axis y axis) HDMI2 disconnected (normal left inverted right x axis y axis) VIRTUAL1 disconnected (normal left inverted right x axis y axis)


The problem (as often is in math) is finding $x$:  \begin{equation} d = \int_{x_0}^x\sqrt{1+[f'(t)]^2} \ \text{dt} \end{equation} It's an inverse problem, and I'm looking for an approximation of the solution for computational purposes. I'm trying to distribute evenly arc-lenght spaced points along the graph of a given real function.  Using the Riemann sum for the integral gives me no hope...any help? EDIT: the Riemann-sum approach (with a subdivision of the interval $[x_0,x]$ in $N$ sub-intervals) looks like this, with $dt\simeq \Delta t:=\frac{1}{N}(x-x_0)$: \begin{equation} d = \Delta t\sum_{k=0}^N\sqrt{1+[f'(x_k)]^2}=\frac{x-x_0}{N}\sum_{k=0}^N\sqrt{1+\Delta t^2\left[f(x_0+(k+1)\Delta t)-f(x_0+k\Delta t)\right]^2} \end{equation} where we're using \begin{equation} f'(x_k)\simeq N\frac{f(x_{k+1})-f(x_k)}{x-x_0} \end{equation}

I'm just a simple high school math student, so please don't eat me =)  In my calculus text, I have the formula:  $$L(x) = \int_{c}^{x} \sqrt{[f'(t)]^2 + 1}\,dt$$  Where $L(x)$ is the arc length of a curve $f(x)$ from $c$ to $x$.  How can I invert this function so that I can find valid values of $x$ to satisfy a given arc length? Something like $L^{-1}(x)$.


In wp_postmeta table I noticed that some of the keys are with '_' (underscore) prefix and and some are without _   What is the major difference between these fields and how they can be used while theming ?  Is there any special use of fields with _ ?  Most of the plugins used this approach to create meta keys but there is not codex on wordpress regarding meta key naming, its not sure if there is any technical difference between these key names.

While trying to perform a WP_Query using meta_query(), I had some trouble because the custom fields created by a plugin had _ in the beginning of its name.   Although I noticed it was stored this way in the database, I had no idea why it was there and thought I had to reference it without the underscore (for the record, that is wrong).  Why do some custom fields start with underscores and others don't? What are the underscores used for? Are they mandatory in some circumstances?


I am making a pyqt program to register and authorize a user. I want to have a start window with buttons that, when clicked, will open either an authorization window or a registration window. But when I import the registration module, for example, the registration window opens instead of the main window. Can you please tell me where I made a mistake? Main module: from PyQt5 import QtWidgets, QtCore from start import Ui_Form #py file with start window ui properties  import registration #registration module class StartWindow(QtWidgets.QMainWindow):     def __init__(self):         super(StartWindow, self).__init__()         self.ui = Ui_Form()         self.ui.setupUi(self)         self.ui.RegButton.clicked.connect(reg_clicked())         self.openreg=registration.mywindow(self)         #self.ui.AuthButton.clicked.connect()      def reg_clicked(self):         self.openreg.show()          app = QtWidgets.QApplication([]) application = StartWindow() application.show() sys.exit(app.exec())  Part of registration module: from PyQt5 import QtWidgets, QtCore import record_proc from reg import Ui_Reg  class mywindow(QtWidgets.QMainWindow):     number_of_samples=1     def __init__(self):         super(mywindow, self).__init__()         self.ui = Ui_Reg()         self.ui.setupUi(self)         self.ui.RecordButton.clicked.connect(self.Recording)         self.ui.AuthButton.clicked.connect(self.Register)         self.ui.CheckLogin.clicked.connect(self.CheckLogin) app2 = QtWidgets.QApplication([]) application2 = mywindow() application2.show() sys.exit(app2.exec())

Given the following code, what does the if __name__ == "__main__": do?  # Threading example import time, thread  def myfunction(string, sleeptime, lock, *args):     while True:         lock.acquire()         time.sleep(sleeptime)         lock.release()         time.sleep(sleeptime)  if __name__ == "__main__":     lock = thread.allocate_lock()     thread.start_new_thread(myfunction, ("Thread #: 1", 2, lock))     thread.start_new_thread(myfunction, ("Thread #: 2", 2, lock))


In the new Ubuntu 18.04:   What's the default GCC version (with which the binaries were built)? What GCC versions are available as separate packages (and what minor version is installed if I install GCC 4, 5, 6, 7 or 8 respectively)? What Clang versions are available as separate packages (and what minor version is installed if I install clang 4 or 5?)   I can't find this in any release notes (and I don't want to have to install just to check.)

How can I check the version of the available package in the Ubuntu repositories without installing it?


As I am traveling Greece from Nepal for the first time to attend a volunteer program of 15 days (including travel days), I have Schengen visa with single entry And also my flight return ticket is fixed already. I have to return after completion of my program.  Can I extend my Schengen visa from Greece? As I want to visit my relatives who lives in Spain and Portugal. What if I stay more than 15 days in my owns. Is not it that the Schengen visa is valid for 90 days?

My daughter applied at the Italian Consulate in Philadelphia, and they gave her two entries for 20 days (we thought it was for 20 days each entry). She was in Italy 12 days, then went to England for 1 week and flew to Venice to take a 10-day cruise. She couldn't make it because they said she has only 8 remaining days, but she still has a land tour already paid this week.  What can she do? Can she extend the Schengen visa for 12 more days? Right now, she is in Madrid, but next week she has to fly from Barcelona to Paris to start with the tour. What would happen if she decides to take the tour with the expired visa? She is a US permanent resident.