Prove that for every $x,y\in\mathbb{R},$   $$\dfrac{|x+y|}{1+|x+y|}\le\frac{|x|}{1+|x|}+ \frac{|y|}{1+|y|}.$$   I really don't know how to start. I thought to dividing it into 4 parts when $(x<0) \land (y>0)$, $(x>0)\land (y<0)$, $(x>0)\land (y>0)$, $(x<0)\land (y<0)$ but I didn't get much from this.

Prove that for every $a, b\in R\setminus\{0\}$ is correct this inequality:  $$\frac{|a+b|}{1+|a+b|}<\frac{|a|}{1+|a|}+\frac{|b|}{1+|b|}.$$


Let $C_b((a,b))$ be the space of continuous and bounded functions on $(a,b) \subset \mathbb{R}$, let $||f||_\infty := \sup\{|f(x)| : x \in (a, b)\}$. Is ($C_b((a,b)),||\cdot||_\infty)$ a complete metric space? I really have no idea how to proceed with this problem... Sorry for my english skills, english is not my first language...

Let $C=C[0,1]$ be the space of all continuous functions on $[0,1]$. Define $\|f \|=\max \ |f(x)|$. I want to show that $C$ is a Banach space.     Below is my attempt and I was wondering if it's ok.    I know I have to show that $C$ is a complete normed space. Clearly, $\|f\| \geqslant 0$ and $\|f\|=0 \Leftrightarrow f=0$. $\|cf \|=\max~|cf(x)|=|c|\max |f(x)|=|c| \cdot \|f\|$. $\|f+g\|=\max~|f(x)+g(x)|\leq \max~|f(x)|+\max~|g(x)|=\|f\|+ \|g\|$. So $C$ is a normed space.   Next, I show that every Cauchy sequence in $C$ is convergent. Let $\{f_n\}$ be a Cauchy sequence in $C$. Let $\varepsilon \gt 0.$ Then $\exists$ an $N_1$ such that $$ \max~|f_n(x)-f_m(x)| \lt \frac{\varepsilon}{2}$$ for $n, m \gt N_1$ and $x\in[0,1]$.  But there is a subsequence $f_{k_n} $, which converges to $f$. So $\exists$ an $N_2$ such that $$ \max~\left|f_{k_n} - f\right|\lt \frac{\varepsilon}{2}$$ for each $n\gt N_2$.  Now Let $N = \max\{N_1, N_2\}$, if $n \gt N$ then $k_n \geqslant n\gt N$. So we have $$ \max~\left|f_n(x) - f(x)\right| \leqslant \max~\left|f_n - f_{k_n}\right| + \max~\left| f_{k_n} - f\right| \lt\frac{\varepsilon}{2} + \frac{\varepsilon}{2} = \varepsilon.$$  Thus, $\|f_n-f\| \to 0$ as $n\to \infty$. $\quad \square$  Thanks.


At the moment, the pages that come up under the Tags tab display synonyms at the end of the list. There's little indication that they're synonyms; they look just like any tag that's used once. Only alphabetization on the page where the single-use → synonym switch occurs gives any indication that certain tags are synonyms at all.  We already identify tags that are used multiple times by appending a number, like "× 574." Can we append something similar for synonyms, like "× 0" or "(s)"?

Is [bugs] a tag with one question, or a tag synonym? Can't tell... can you? This is a real problem when trying to manage tags.  Please differentiate tag synonyms in the list, possibly with a different border.


Tried to cast the datatime object ,which is queried from database. Value is in UTC time. is it affect the local timezone when i tried to cast the object ? var daytime = (DateTime)reader["day"]; reader["day"] is a object and value is in UTC time. For accessing the value i changed it into DateTime. my intention is i want to convert this value to epoch time. var daytime = (DateTime)reader["day"]; long epochTicks = new DateTime(1970, 1, 1).Ticks; long unixTime = ((daytime.Ticks - epochTicks) / TimeSpan.TicksPerSecond);

We are developing a C# application for a web-service client. This will run on Windows XP PC's.  One of the fields returned by the web service is a DateTime field. The server returns a field in GMT format i.e. with a "Z" at the end.  However, we found that .NET seems to do some kind of implicit conversion and the time was always 12 hours out.  The following code sample resolves this to some extent in that the 12 hour difference has gone but it makes no allowance for NZ daylight saving.  CultureInfo ci = new CultureInfo("en-NZ"); string date = "Web service date".ToString("R", ci); DateTime convertedDate = DateTime.Parse(date);               As per :     UTC/GMT Offset       Standard time zone: UTC/GMT +12 hours   Daylight saving time: +1 hour   Current time zone offset: UTC/GMT +13 hours     How do we adjust for the extra hour? Can this be done programmatically or is this some kind of setting on the PC's?


I uploaded code on server, whan i send ain on mine outlook email, email is put to spam folder, same problem is when i refresh page, mail get sent again. Can anyone help me out with code? Forword, Thank you very much!

This is a tricky one and I've always relied on techniques, such as permission-based emails (i.e. only sending to people you have permission to send to) and not using blatantly spamish terminology.  Of late, some of the emails I send out programmatically have started being shuffled into people's spam folder automatically and I'm wondering what I can do about it.  This is despite the fact that these particular emails are not ones that humans would mark as spam, specifically, they are emails that contain license keys that people have paid good money for, so I don't think they're going to consider them spam  I figure this is a big topic in which I am essentially an ignorant simpleton.


I have created a custom module and created a yml file to create a menu  system.menu.custom_menu.yml  id: custom_menu label: 'Custom menu' description: 'Custom menu.' langcode: en locked: true dependencies:   - mymod   When I installed my module it creates the the custom menu.  But then When I uninstall the module and try to install it again I get the following exception  exception 'Drupal\Core\Config\PreExistingConfigException' with message 'Configuration objects (system.menu.custom_menu) provided by mymod already exist in active configuration' in /var/www/drupal8/core/lib/Drupal/Core/Config/PreExistingConfigException.php:70   What I am doing wrong? Is there any way to remove my configuration (system.menu.custom_menu) from the configurations when I uninstall my module?

I'm writing a custom module for Drupal 8. It defines a field storage configuration object, in a file called modules/mymod/config/install/field.storage.bloom_stem.bs_twitter_ac.yml.  The problem is that this is not removed when I uninstall the module; it is apparently left behind because, when I re-install the module, I get a crash.   drush -y pm-uninstall mymod drush cr drush -y en mymod      exception 'Drupal\Core\Config\PreExistingConfigException' with message 'Configuration objects (field.storage.bloom_stem.bs_twitter_ac) provided by mymod already exist in active configuration'   So it seems I need to some how manually remove this configuration object. Do I need to provide some more code that deletes it when the module is uninstalled?


Given the DEM of a certain Country, and a fishnet that is superimposed on it, I need to compute the average elevation and slope corresponding to each square in the fishnet.  [I am using ArcGIS 10.3.1, licence type: Advanced.]  These are the DEM (shades of grey) and the fishnet (red):   The DEM is not a unique raster, but a handful of smaller maps. Their resolution is 10x10 km, whereas the fishnet squares are 2x2 km.  I tried to create a , and then I used Extract -> Clip from ArcToolbox using the DEM as input features and the fishnet as clip features. I thought this wouldhave produced a unique raster map, but I was wrong, and the result is essentially a grid with the DEM resolution (10x10 km) and a bunch of table attributes which do not refer to elevation.   The intended outcome was, instead, to get the average elevation and slope for each one of the smaller tiles in the fishnet.  What is it the best strategy to achieve this?

I'm using ArcMap 10.3, and here's what I have: I have an angled vector grid created through GME's GenVecGrid tool which has been clipped to an irregular size and angled relative to the xy axes to represent a study area. When I say it's irregular, I mean to say while each cell is full (no partial cells), portions of the rectangular grid have been removed to reflect the study area. Here's an image to show what I mean:     I also have a raster DEM of the area in question (also pictured in the above image link).  Here's what I'm hoping to do: For each cell in the vector grid, I want to find an average elevation from the raster DEM and incorporate this into the vector grid itself (in the attribute table). Ideally, I'd like to use an interpolation method like kriging to find an intelligent average, so to speak.  In searching forums, I have seen recommendations for using the Add Surface Information tool (ArcToolbox > 3D Analyst > Add Surface Information), as well as Interpolate Shape (ArcToolbox > 3D Analyst > Interpolate Shape), but these were unsuccessful.  Can anyone guide me in the right direction?


I lost my Apple ID password and security questions and answers. What do I do?

I have forgotten my Apple Id but i know my password.And my phone need to be activated but the apple id was made mistakenly.Is there any possibility to know my Apple Id?


Aiming to have a large internal HDD to store files, and several OSes on separate disks. They all need to read and write to one storage drive.  Ubuntu (13.04+) Mac OSX (10.8+) Windows (7+)   What format should the drive be? Would like to avoid buying third party software, here's what I have discerned so far:   NTFS - Can't be written to by Mac without buying third party software?      ext3 - Windows can't read, . Mac has  HFS+ -  exFAT - , but

I would like my external drives to be readable and writable from Linux, Mac OS X and Windows.   FAT32 works, but the 4 GB file size limit is a showstopper these days. Are there any alternatives?


I have to use laptop for quite a few months now, because my desktop monitor is being repaired! I need to use my laptop as a screen for my desktop PC. How can that be done? Is that Possible?

Is it possible to make my laptop's screen act as a second monitor for my desktop computer?


I spent time on due diligence and did not find this exact question, which surprised me greatly. I think it's a hugely important issue when it comes to Harry Potter. I see many questions posed with the presumption that Harry was a Horcrux -- but was he really? I'll give a couple of canon hints:     ‘Well,’ said Slughorn, not looking at Riddle, but fiddling with the ribbon on top of his box of crystallised pineapple, ‘well, it can’t hurt to give you an overview, of course. Just so that you understand the term. A Horcrux is the word used for an object in which a person has concealed part of their soul.’   [...]   ‘Encase? But how –?’   ‘There is a spell, do not ask me, I don’t know!’ said Slughorn, shaking his head like an old elephant bothered by mosquitoes. ‘Do I look as though I have tried it – do I look   like a killer?’   ‘No, sir, of course not,’ said Riddle quickly.   Half-Blood Prince - pages 464 - 465 - Chapter twenty-three, Horcruxes   Was Harry an actual, legitimate Horcrux? Why or why not?  I'm looking only for a canon-based answer, so basically I'm willing to accept Word of God (J.K. Rowling), a direct quote from any of the ten Harry Potter books, or a definitive statement from Pottermore. Just as a general FYI, I am 100% disinterested in anything the HP Wikia has to say on the matter, and will likely skip over any answer with Wikia content. If this question is found to be a duplicate, by all means vote accordingly.

To make a Horcrux, certainly murder can't be the only requirement. It is obvious a proper spell is needed for completing a Horcrux. Voldemort could have made a thousand Horcruxes, as he had already murdered a thousand people. But, how on earth did Harry become a Horcrux, with Voldemort murdering his mom and not using the Horcrux-making spell? Certainly Avada Kedavra is not the spell used for making a Horcrux.


I'm trying to write a shell script so that when I reinstall my Ubuntu again. I could just run script and retain all the packages. And I'm planning to pass password in form of argument.  My question here is how can i enter into sudo domain without manually entering password. As I'm also planning to design a UI where it can't access the terminal there.  Ex:  ./recover.sh password   Would appriciate the response ;)  with regards  pavan

On busy days, I'd like to run   $ ./configure && make && sudo make install && halt   on the night and go to bed, hoping the application would automatically be installed. But what I see the next day is the screen where sudo asks me for the password. So how could I run sudo with password in one command line, or is there any other method to do this?


I am trying to find a way to get spell checking to play a sound when an error is detected. I don’t mean when an error is “corrected”, but just when one is detected.  A long time ago, you would add a spell checker to your Mac via a third party application. I remember one which made a sound every time it detected an error, which meant that you didn’t have to look at the screen to notice errors.  I don’t think the feature is built into OS X's spelling error correction (why not?). Is there possibly a third part app that will do this simple task?  The following questions hint at the problem:   &   but (a) they are more concerned with auto-correct; (b) they are a few years old; and (c) they don’t have a real solution.

There are many times when I curse the autocorrection mechanism for changing what I typed, but overall, much of the corrections are welcome so I don't really want to disable it. I do want to have it do it's work but alert me when it makes each change so I don't have to proofread everything or focus with perfect attention to the screen to see the momentary red and/or blue underlining that alerts me to the machine override.  I would love a way to turn on an audible beep (customizable of course) so that I also get a warning each time my typing gets corrected (and only when autocorrection occurs).


I have an XML schema in which I know that an element has to have a particular child, but I do not know the depth at which that child will exist at. Take the following example XML:  <node id="top">    <node id="inner">      <event/>    </node> </node>  <node id="top">    <event/> </node>   The only requirements I have is that an <event> element must be a descendant of the <node id="top"> element, but I do not know at what depth it will occur. In other words, there could be any number of <node id="inner"> elements in between the top <node id="top"> and an <event> element. In the example above, each of those are valid within the schema. My attempted solution was:  <xs:element name="node">     <xs:complexType>         <xs:sequence>             <xs:element name="node" minOccurs="0">                 <xs:complexType>                      <xs:sequence>                         <xs:element name="event"/>                      </xs:sequence>                    <xs:attribute name="id" fixed="inner"/>                 </xs:complexType>             </xs:element>         </xs:sequence>       </xs:complexType>       <xs:attribute name="id" fixed="top"/> </xs:element>   But, as expected, this does not take into account many "depths" of <node> elements that can occur after the <node id="top"> element.

I need to create an XML schema that validates a tree structure of an XML document. I don't know exactly the occurrences or depth level of the tree.  XML example:  <?xml version="1.0" encoding="utf-8"?> <node>   <attribute/>   <node>     <attribute/>     <node/>         </node> </node>    Which is the best way to validate it?  Recursion?


When taking double/triple derivatives of multivariable functions, we see that no matter which order we take the derivative in, as long as we take the derivative od the function with respect to the same number of variables, the same number of times, our answer is the same? Is there an intuitive explanation for this? I cannot seem to understand how.

In the   post in this stack exchange, one of the answers to the questions of do partial derivatives commute is: Second order partial derivatives commute if f is $C^2$ (i.e. all the second partial derivatives exist and are continuous). This is sometimes called Schwarz's Theorem or Clairaut's Theorem. This theorem is in my textbooks, yet I cannot seem to find the proof in them. I have tried proving the theorem yet I have gotten stuck. So, what is the proof of Clairaut's Theorem, or why do partial derivatives commute? If the proof is too long, a link to the proof with an intuitive explanation will be sufficient.


I would want to know what the shafts, which Luke fell through, were intended for? Were they dump shafts or maybe air shafts?

Towards the end of "The Empire Strikes Back", Luke escapes from Darth Vader by jumping down a chute... which opens up into open air, and leaves him dangling on a mast...  Why does Cloud City have these death traps in the first place?


I inserted four figures, one by one. And then I added one paragraph of content. But I find the paragraph between the figures - First two figures, then one paragraph, and then one figure. How can I keep the position of the figures in the right place?    My code is like this:  \documentclass{article}     \usepackage{subfigure}     \begin{document}     \begin{figure}[hbtp]     \centering     \includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment1.png}     \caption{First Time Experiment}     \end{figure}     \begin{figure}[hbtp]     \centering     \includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment2.png}     \caption{Second Time Experiment}     \end{figure}     \begin{figure}[hbtp]     \centering     \includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment3.png}     \caption{Third Time Experiment}     \end{figure}     \begin{figure}[hbtp]     \centering     \includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment4.png}     \caption{Fourth Time Experiment}     \end{figure}  As the figures do, the researcher observes the following principles: ajie% As the figures do, the researcher observes the following principles: ajie% As the figures do, the researcher observes the following principles: ajie% As the figures do, the researcher observes the following principles: ajie\\%\ \end{document}

How to influence the position of float environments like figure and table in LaTeX?   This is a general question and should collect useful answers for all users. I hope we can use this as a reference


Could somebody please explain the following behaviour?  X=2*[[]] print X X[0].append(1) print X   yields  [[], []] [[1], [1]]   I would expect the last list to be [[1], []]. Indeed, the following  X=[[],[]] print X X[0].append(1) print X   yields  [[], []] [[1], []]   Why this difference?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


Let the set of instances be generated by the function , where $ε$ is random, uniformly distributed noise. Also, assume that you are using a fifth degree polynomial for regression.

I am going over the lectures on Machine Learning at Coursera.   I am struggling with the following. How can the partial derivative of   $$J(\theta)=-\frac{1}{m}\sum_{i=1}^{m}y^{i}\log(h_\theta(x^{i}))+(1-y^{i})\log(1-h_\theta(x^{i}))$$  where $h_{\theta}(x)$ is defined as follows  $$h_{\theta}(x)=g(\theta^{T}x)$$ $$g(z)=\frac{1}{1+e^{-z}}$$  be $$ \frac{\partial}{\partial\theta_{j}}J(\theta) =\sum_{i=1}^{m}(h_\theta(x^{i})-y^i)x_j^i$$  In other words, how would we go about calculating the partial derivative with respect to $\theta$ of the cost function (the logs are natural logarithms):  $$J(\theta)=-\frac{1}{m}\sum_{i=1}^{m}y^{i}\log(h_\theta(x^{i}))+(1-y^{i})\log(1-h_\theta(x^{i}))$$


I get error "Procedure tr_employee_tbl_forinsert Column name or number of supplied values does not match table definition" when I run the INSERT query below. What should I do?  create table employee_tbl ( EmpID int primary key, FirstName varchar(50), LastName varchar(50), Salary float, MobileNo varchar(15) )  create table employeeaudit_tbl ( EmpID int primary key, AuditData varchar(50) ) GO create trigger tr_employee_tbl_forinsert on employee_tbl for insert as begin         declare @EmpID int         select @EmpID = EmpID from inserted          insert into employeeaudit_tbl         values('New employee with EmpID = ' + CAST(@EmpID as nvarchar(5)) +'is added at ' + CAST(GETDATE() as nvarchar(50))) end GO

create table employee_tbl ( EmpID int primary key, FirstName varchar(50), LastName varchar(50), Salary float, MobileNo varchar(15) )  create table employeeaudit_tbl ( EmpID int primary key, AuditData varchar(50) )  select * from employee_tbl select * from employeeaudit_tbl  create trigger tr_employee_tbl_forinsert on employee_tbl for insert as begin         declare @EmpID int         select @EmpID = EmpID from inserted          insert into employeeaudit_tbl         values('New employee with EmpID = ' + CAST(@EmpID as nvarchar(5)) +'is added at ' + CAST(GETDATE() as nvarchar(50))) end


Let $f: X \to Y$ be a morphism of schemes. Consider the graph morphism $(id,f): X \to X \times Y$. Denote by $\Gamma_f \subset X \times Y$ it's schematic image. Futhermore the projection $pr_X: X \times Y \to X$ induces the morphism $p:\Gamma \to X$  My question is under what conditions (preferably the most weak ones) on $f,X,Y$ the graph morphism $(id,f)$ and $pr$ are isomorphisms.  I know:  -$(id,f)$ is always an immersion and even a closed immersion (by a base change argument) if $Y$ is separable (can be seen by a base change argument)  -it's (set theoretically) injective since $pr . (id,f)= id$ for $pr: X\times Y \to X$.  -then there are always some boring conditions like when $f$ is already an isomorphism or similar  Does anybody know the most weakingst conditions which garantee that $(id,f)$ is an iso

Let $S$ be a scheme and let $f:X\to Y$ be a morphism of separated $S$-schemes.  shows that, when $X$ is reduced, the obvious morphism $g_f:\Gamma_f \to X\times_S Y\to X$ is an isomorphism, where $\Gamma_f$ is the scheme-theoretic image of $\Delta_f:X\to X\times_s Y$.     Can we show that $g_f$ without assuming that $X$ is reduced?   I see how the reduced induced structure is being used there, but I do not see if $X$ being reduced affects the statament, $X$ cannot have double/triple/... points if $\Gamma_f$ does not! So, I wonder if there is a probably more elaborate proof that shows $g_f$ to be an isomorphism.   The only assumption I have is that $S$ is Noetherian.   A hint or a reference would be appreciated.


I don't understand what happened. Before when I saved the file it worked fine, but when I came back and reopened it, this problem started happening. (It is most visible with the character's eyes.)    The object is visible in the viewport, but it appears nowhere in the outliner. (Yes, I have scrolled down through the entire outliner to check.) The objects even appear in the preview render and work fine there,(Sorry I couldn't post more than 2 pictures.) but once I press F12 for the final render the objects completely disappear.    I am using cycles render. I am hoping someone might be able to help me, I have searched a lot, but have not been able to find an answer to my problem anywhere.

I have a model which you can see here (camera perspective).    In the second image, you can see how the render turned out.    I'm at my wit's end trying to figure our why it's not showing up in the render. If anyone needs more information, just ask and I'll get it to you. I've already checked the normals and they're not the cause.


I'm looking for a name of topic(s), theories which describe the situation provided below:  Let's say we have a 6-sided fair dice. And after 6000 throws we have the following results:   Digit 1: 1145 times Digit 2: 1089 times Digit 3: 614 times Digit 4: 1132 times Digit 5: 1022 times Digit 6: 998 times   According to the theory of probability the chance of having any digit in the next throw is 1/6 which is fair enough, but when I look at the results of the previous throws I assume that I should expect more throws of digit #3 soon, cause according to the law of large numbers the fair dice results should balance over time. So I'm looking for a way to calculate / measure how the fact may affect the probability of getting digit 3 in the next throw.

As we all know, if you flip a coin that has an equal chance of landing heads as it does tails, then if you flip the coin many times, half the time you will get heads and half the time you will get tails.  When discussing this with a friend, they said that if you were to flip the coin 1000 times, and lets say the first 100 times it landed heads, then the chances of landing a tail was increased (the logic being that if it is unbiased, then by the time you have flipped it 1000 times you will have roughly 500 heads and 500 tails, so tails must be more likely).  I know that to be a fallacy, as past results don't influence future results. Is there a name for that particular fallacy? Also, is there a better explanation of why this is fallacious?


This script should auto mount a file system on a Linux server.  testcheck=`df -h | awk '{print $6}' | grep "/test"`;  if [$tescheck -ne "/test"] then     mount /test else     echo "failed"; fi   I'm having a problem in the condition for making if statement true or false.  What am I doing wrong? Are there any alternatives that I can use?

I am using the below script to move two days back when script runs at starting two days of the year and also check first and second days of every month and move two days back. if [$month="01"] && [$day="01"]; then         date="$last_month/$yes_day/$last_year"         fulldate="$last_month/$yes_day/$last_year" else         if [$month="01"] && [$day="02"]; then                 date="$last_month/$yes_day/$last_year"                 fulldate="$last_month/$yes_day/$last_year"         else                 if [ $day = "01" ]; then                         date="$last_month/$yes_day/$year"                         fulldate="$year$last_month$yes_day"                 else                         if [ $day = "02" ]; then                                 date="$last_month/$yes_day/$year"                                 fulldate="$year$last_month$yes_day"                         else                                 date="$month/$yes_day/$year"                                 fulldate="$year$month$yes_day"                         fi                 fi         fi fi  But my bad am getting the below error message Etime_script.sh: line 19: [06=01]: command not found Etime_script.sh: line 24: [06=01]: command not found


I need to order results in the same order, as they are in IN(...) clausule. How to do this? For example:  SELECT id, name, desc FROM my_table WHERE id IN (8, 4, 19, 48, 15)   So I need to have results ordered in this order 8, 4, 19, 48, 15.

I am wondering if there is away (possibly a better way) to order by the order of the values in an IN() clause.  The problem is that I have 2 queries, one that gets all of the IDs and the second that retrieves all the information. The first creates the order of the IDs which I want the second to order by. The IDs are put in an IN() clause in the correct order.  So it'd be something like (extremely simplified):  SELECT id FROM table1 WHERE ... ORDER BY display_order, name  SELECT name, description, ... WHERE id IN ([id's from first])   The issue is that the second query does not return the results in the same order that the IDs are put into the IN() clause.  One solution I have found is to put all of the IDs into a temp table with an auto incrementing field which is then joined into the second query.  Is there a better option?  Note: As the first query is run "by the user" and the second is run in a background process, there is no way to combine the 2 into 1 query using sub queries.  I am using MySQL, but I'm thinking it might be useful to have it noted what options there are for other DBs as well.


I have a JPanel that has a button which when pressed is to create a new circle. However, that doesn't happen. A new circle doesn't appear and when I resize a window the existing circle breaks, the clone of the button appears on the other side of the panel and everything freezes.  class Panel extends JPanel  {      private JButton button;     private Ellipse2D.Double[] circles;     Integer count;      public Panel()  {             setup();     }      private void setup()  {             count=new Integer(0);             circles=new Ellipse2D.Double[10];             button=new JButton(count.toString());             button.addActionListener(new ActionListener() {                @Override                public void actionPerformed(ActionEvent e) {                            circles[count]=new                                Ellipse2D.Double(10, 10, 100, 100);                            count++;                            button.setText(count.toString());                     }                 });                 add(button);         }       public void paintComponent(Graphics g)  {             super.paintComponent(g);             paintStuff(g);         }      private void paintStuff(Graphics g)  {             Graphics2D g2=(Graphics2D) g;             g2.setPaint(Color.RED);             Ellipse2D.Double circle2=new Ellipse2D.Double(getWidth()/2-                     getHeight()/4,                     getHeight()/4, getHeight()/2, getHeight()/2);             g2.draw(circle2);              if (count!=0)  {                 for (Ellipse2D.Double circle: circles)  {                         g2.draw(circle);                 }             }     } }  public class Frame extends JFrame  {      private Panel panel;      public Frame()  {         panel=new Panel();         add(panel);      }       public static void main(String[] args)  {           Frame frame=new Frame();      } }   What is wrong and what should I do to fix it?

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?


This might be a silly question. For $f$ an integrable, complex-valued function, its Fourier transform is  $$ \hat{f}(s) = \frac{1}{\sqrt{2\pi}}\int_{-\infty}^{+\infty} e^{-isx}f(x)\, \mathrm{d}x $$  I want to show that if $\int xf(x) \, \mathrm{d}x$ exists then $\hat{f}$ is differentiable, with  $$ (\hat{f})'(s) = - \frac{i}{\sqrt{2\pi}}\int_{-\infty}^{+\infty} xe^{-isx}f(x)\, \mathrm{d}x $$  for every $s$. I tried using the definition of derivative and got to  $$ (\hat{f})'(s) = \lim_{h \to 0}\frac{1}{h}\int_{-\infty}^{+\infty} f(x)e^{-isx}[e^{-ihx}-1] \, \mathrm{d}x $$  and I'm not really sure where to go. Can anyone point me in the right direction? Thanks.

Let us define the Fourier transform of the Lebesgue-summable function $f\in L_1(\mathbb{R},\mu_x)$ as $F[f](\lambda)=\int_{\mathbb{R}}f(x) e^{-i\lambda x} d\mu_x$, where $\mu_x$ is the Lebesgue linear measure. Kolmogorov-Fomin's (p. 430 ) states that, if $x\mapsto xf(x)$ is Lebesgue-summable too, then the Fourier transform is differentiable and$$\frac{d}{d\lambda}F[f](\lambda)=-i\int_{\mathbb{R}}x f(x) e^{-i\lambda x} d\mu_x$$  EDIT: I would be very grateful to the people having voted to close the question, and to anybody else, if they explained how to use the  to prove this equality, which I am not able to do. I am trying to teach myself and cannot afford university for the moment and have not got the sufficient mathematical ability to understand how that result implies this equality. I heartily thank you all!!!  Previous trial of mine which may or may not be useful to prove the given equality: In order to prove the statement to myself I had thought that the fact that if the sequence $\{\varphi_n\}\subset L_1(\mathbb{R},\mu_x)$ converges to $\varphi$ with respect to the metric of $L_1(\mathbb{R},\mu_x)$, then $F[f_n]\xrightarrow{n\to\infty} F[f]$, but I cannot apply it. In fact I see that the derivative $F[f]'(\lambda)$ can be seen, if we define $\varphi_n(x)=f(x)\frac{e^{-ih_n x}-1}{h_n}$, where $\{h_n\}$ converges to 0, as the limit $$\lim_n \int_{\mathbb{R}}f(x)\frac{e^{-i(\lambda+h_n)x}-e^{-i\lambda x}}{h_n}d\mu_x=\lim_n \int_{\mathbb{R}} f(x) \frac{e^{-ih_n x}-1}{h_n} e^{-i\lambda x} d\mu_x$$$$=\lim_n F[\varphi_n](\lambda)$$but I cannot prove that $\int_{\mathbb{R}} f(x) \frac{e^{-ih_n x}-1}{h_n} e^{-i\lambda x} d\mu_x$ converges to $-i\int_{\mathbb{R}}x f(x) e^{-i\lambda x} d\mu_x$. I thought about Lebesgue's dominated convergence theorem, but I am not convinced at all that we can majorate $|\varphi_n(x)|$ with a summable function and I am not sure this is the right path to prove the desired equality...  P.S.: I assume that the equality holds for any $f\in L_1(\mathbb{R},\mu_x)$ because the book does not specify any other conditions, but it is perfectly in the style of the book to state theorems valid only under certain conditions without explicitly declare them. So, if you noticed that some other condition is needed...


How do I open a file geodatabase using QGIS 3.6.2?

I have spent around 2 days to find the way to open GDB (Esri geodatabase) in QGIS (or any other open source software) but still without success.  I have downloaded the newest OSGeo4W installer and tried the setup - express desktop install - all packages, as well as advanced install incl gdal-filegdb.  Can you describe a more detailed procedure, including installation and how to open .gdb in QGIS (OSGeo4W installation)?


I have a sticky situation and I'm not quite sure how to deal with it.  As part of branding a company for a friend/client I have created some cartoon type characters (as well a logo, fonts, colours, feel and all the other branding stuff). Now this is a good friend so I'm not necessarily concerned about losing business but he's involved someone else to do some facebook marketing. This third party wants all the individual assets.  I'm doing all this work at a reasonable rate and would like to retain control of the artwork used.  As this is a friend I have offered to create backgrounds for the ads for free when ordinarily I would be negotiating a better rate for handing over the constituent parts of my design work.  The third party is pressing for the parts so I would welcome any input on how to proceed and what my expectations should be.  Thanks.

If you design a piece for print. It gets reproduced several times over the course of a few years. Then the client doesn't return for any work for a few more years. And suddenly you are contacted asking for native files (Indesign, Illustrator, Photoshop). As the client puts it, "We just want to be able to make minor changes, we aren't designers."  Now, there is absolutely value in the native files. They are my "secret recipe" as a designer and anyone asking for that recipe should provide compensation for the ease of reusing, repurposing, and altering the recipe.  How do you explain to this client that there is value in the native files?  How do you counter the "But we already paid for the design." argument?  Note: I know I own the files. I know my contract states I own the files. Heck even without a contract, US Copyright law states I own the files.  What I'm seeking is an elegant, less argumentative, method of explaining the file ownership to the uneducated client. Reciting legal statutes and contract clauses doesn't often make for friendly client relations. My goal is to find a method of explaining so it is fully understood by the client without the appearance of a contract clause which forces them to do something against their will. I want the client to respect and not resent these types of contract clauses.


I locked my MacBook Air through Find My iPhone app because I thought I had lost it. One day later I found it. I tried to unlock it with the PIN I had set and apparently I remembered the PIN wrong.  I logged into iCloud from another PC and got my PIN right. When I tried to insert it again it wasn’t possible. In the screen I could only see Wrong Passcode. Try Again. There is no place where I can insert the passcode. If I restart it, it says that my device is disabled and I have to wait 60 min. After 60 min, same message Wrong Passcode. Try Again. and no place where to insert passcode.  I tried what other people suggested in similar posts (option+cmd+R) and it didn’t work for me.  How do I resolve the issue?

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


Good day, NOTE: I'm running Ubuntu 20.10 on VM Box I get the following error: apt-get update fails to fetch files, “Temporary failure resolving …” error. I tried literally every "fix" I can per this user group and others on the net.  I still have the same error. help please;

Err http://archive.canonical.com natty InRelease     Err http://security.ubuntu.com oneiric-security InRelease                Err http://extras.ubuntu.com natty InRelease                             Err http://security.ubuntu.com oneiric-security Release.gpg   Temporary failure resolving ‘security.ubuntu.com’ Err http://archive.canonical.com natty Release.gpg   Temporary failure resolving ‘archive.canonical.com’ Err http://extras.ubuntu.com natty Release.gpg   Temporary failure resolving ‘extras.ubuntu.com’ Err http://gb.archive.ubuntu.com oneiric InRelease Err http://gb.archive.ubuntu.com oneiric-updates InRelease Err http://gb.archive.ubuntu.com natty-backports InRelease Err http://gb.archive.ubuntu.com oneiric Release.gpg   Temporary failure resolving ‘gb.archive.ubuntu.com’ Err http://gb.archive.ubuntu.com oneiric-updates Release.gpg   Temporary failure resolving ‘gb.archive.ubuntu.com’ Err http://gb.archive.ubuntu.com natty-backports Release.gpg   Temporary failure resolving ‘gb.archive.ubuntu.com’  Reading package lists... Done W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric/InRelease       W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric-updates/InRelease   W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/natty-backports/InRelease   W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/InRelease   W: Failed to fetch http://archive.canonical.com/ubuntu/dists/natty/InRelease   W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/natty/InRelease   W: Failed to fetch http://archive.canonical.com/ubuntu/dists/natty/Release.gpg  Temporary failure resolving ‘archive.canonical.com’ W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/Release.gpg  Temporary failure resolving ‘security.ubuntu.com’ W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/natty/Release.gpg  Temporary failure resolving ‘extras.ubuntu.com’ W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’ W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric-updates/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’ W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/natty-backports/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’ W: Some index files failed to download. They have been ignored, or old ones used instead.   This is what I'm seeing when I try to run sudo apt-get update. I did an update on my instance yesterday and am now experiencing this.


I need to have a very fast disk for keeping cache. How can I do that in Linux?

I have a question,in linux, is there any method to mount a block of memory as a filesystem? For example, in X86 architecture, when power on, I reserve a  block of memory about 8 Mbytes, and then when linux startup, I mount this block of memory as a filesystem and then read and write file to the file system ? What will be the fs type?


I want to write an element of a matrix on two lines is possible ??? I have an element of a matrix that is too long I want to write it on 2 lines. Thank you  $\tilde{A}_{Long}=\left(\begin{matrix} X_{\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont u}}}&X_{\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont w}}}&X_q-M_{33}\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont w}}_0&-(mg-B_u)cos(\theta_0)\\ Z_{\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont u}}}&Z_{\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont w}}}&Z_q-M_{11}\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont u}}_0&-(mg-B_u)sin(\theta_0)\\ M_{\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont u}}}&M_{\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont w}}}&M_{q}-M_{11}.x_G\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont u}}_0-M_{33}.z_G\textrm{{\fontfamily{lmr}\fontshape{ui}\selectfont w}}_0&(x_Gmg+x_BB_u)sin(\theta_{0})-(z_Gmg+z_BB_u) cos(\theta_{0})\\  0&0&1&0\\ \end{matrix}\right)$

I want to write a big matrix and I want to write it in two lines like the picture but I cannot find the way!


This may seem like a silly question but before I go shooting my mouth off in a team meeting I want to absolutely certain that I understand things correctly.  I have a Java application that references a third party jar file.  My code only uses their interfaces.  If the third party gives me a different version of their jar file and I simply replace the old jar with the new do I need to recompile my application?  Is this still true if the interface method signature contains one of their classes, e.g.  public void thirdPartyMethod(ThirdPartyEvent e);   It is my understanding that unless the interface has changed I do not have to recompile.  Even if the ThirdPartyEvent class is changed (new methods added) I still do not have to recompile unless I want to access those new methods.  Is my understanding correct?  Thanks in advance.  EDIT: This question can be closed it is a duplicate.  Didn't see it when I did a search - don't know how I could of missed it...  BTW It was not clearly stated in my question but the API has not changed - the interfaces are the same.  FINAL EDIT: I do want to note though that there are times when deploying an new version of a third party jar is far easier than deploying an entire re-compiled application...  As a matter of practice I do routinely re-compile, there is absolutely no harm in doing so. However, where I work there is a complete lack of understanding on how Java Interfaces work.  Everyone was worried that the new third party implementation has changed and our application would not work anymore.  I told them that would only happen if the third party changed the API or gave us a broken jar.  Anyway long story short, I thought that if I could show that you could replace the jar and not recompile that would illustrate (at least in part) how interfaces work.  I have emailed links to this post, the duplicate and Mik378's included link in the hopes that it will finally sink in...

I have a java application that uses some third party API. The third party jar files change fairly frequently because of all kinds of patches, but the API itself does not change that often.   Do I have to recompile my application every time the third party jar changes?


I have run following command accidentally   sudo chown [username] -hR /   Now sudo su getting error:  sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set   How to Solve This?

I stupidly ran sudo chown -R carlos:carlos / and carlos is my user. This changed all files to be Carlos and I could not boot up again (because the root files were now owned by #1000) and I cant get sudo acess in live cd (because the owner of /usr was changed to my user). Can anyone help me? FYI I have mounted my hard drive.


i have a Json Object in Javascript, looking like this:  { "properties": {     "processowner" : { "valueType": "text" },     "withwhat" : { "valueType": "text" },     "withwho" : { "valueType": "text" },     "processstep" : { "valueType": "text" },     "cluster" : { "valueType": "text" } }, "items": [     {         "label": "anytitle",         "processowner": ["Name"],         "withwhat": ["ben\u00f6tigtes Material","ben\u00f6tigtes Material2","ben\u00f6tigtes Material3"],         "withwho": ["Verantwortliche Person"],         "processstep": ["1. Schritt 1","2. Schritt 2","3. Schritt 3","4. Schritt 4","5. Schritt 5"],         "cluster": ["anyname"]     },     {         "label": "anytitle",         "processowner": ["Name"],         "withwhat": ["ben\u00f6tigtes Material","ben\u00f6tigtes Material2","ben\u00f6tigtes Material3"],         "withwho": ["Verantwortliche Person"],         "processstep": ["1. Schritt 1","2. Schritt 2","3. Schritt 3","4. Schritt 4","5. Schritt 5"],         "cluster": ["anyname"]     }, ........ }   What i want is only the "items" part. Looking like this:  [     {         "label": "anytitle",         "processowner": ["Name"],         "withwhat": ["ben\u00f6tigtes Material","ben\u00f6tigtes Material2","ben\u00f6tigtes Material3"],         "withwho": ["Verantwortliche Person"],         "processstep": ["1. Schritt 1","2. Schritt 2","3. Schritt 3","4. Schritt 4","5. Schritt 5"],         "cluster": ["anyname"]     },     {         "label": "anytitle",         "processowner": ["Name"],         "withwhat": ["ben\u00f6tigtes Material","ben\u00f6tigtes Material2","ben\u00f6tigtes Material3"],         "withwho": ["Verantwortliche Person"],         "processstep": ["1. Schritt 1","2. Schritt 2","3. Schritt 3","4. Schritt 4","5. Schritt 5"],         "cluster": ["anyname"]     }, ........ ]   I tried to access it with      objectname.items But i always get "undefined" when printing out on console.   edit:  function getJSON() { var req = https.get(options, function(response) {       // handle the response       var res_data = '';       response.on('data', function(chunk) {         res_data += chunk;       });       response.on('end', function() {             var wikiJSON = res_data;             console.log(wikiJSON.items);       });     });     req.on('error', function(e) {       console.log("Got error: " + e.message);     });     req.end();                 }

Given a string of JSON data, how can I safely turn that string into a JavaScript object?  Obviously I can do this unsafely with something like:  var obj = eval("(" + json + ')');   but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval.


I want to use the outline of the sprocket and inside it i want to put an alaphabet.. how to remove the inner part and make it all one color.?

I'm editing an svg in Inkscape and I have an object on top of another object. I'd like to use the shape of the top object to cut the object beneath it.  For those who are familiar with GIMP, I'm trying to do something like the "alpha to selection" tool.


/**  * @author paula  */  function A(name){     this.name = name;     this.sayHi();     this.$sayHi();     this.sayBye(); };  (function(){     this.sayHi = function(){         console.log("[sayHi] Hi there, "+ this.name);     };      this.$sayHi = function(){         console.log("[$sayHi] Hi there, " + this.name);     };      this.sayBye = function(){         console.log("[sayBye] Bye bye now, " + this.name);     }; }).call(A.prototype);  var objA1 = new A("Luca");   Found this article:  javascript.crockford.com/code.html where is mentioned that "Do not use $ (dollar sign) or \ (backslash) in names. Most variables and functions should start with a lower case letter"  I have some framework code with many functions prefixed with dollar sign (functions that look similar to $sayHi). Is a function prefixed with $ intended to be used for special purposes ? Thanks.

I quite often see JavaScript with variables that start with a dollar sign. When/why would you choose to prefix a variable in this way?  (I'm not asking about $('p.foo') syntax that you see in jQuery and others, but normal variables like $name and $order)


I did something stupid. I reinstalled Windows on my computer but decided to leave the old installation on the drive instead of reformatting. Now I'm trying to delete the old Windows folder and for the most part have been successful, but cannot for the life of me delete two files:   E:\Windows\System32\Macromed\Flash\Flash64_11_1_102.ocx E:\Windows\SysWOW64\Macromed\Flash\Flash11e.ocx   When I try to delete the files I get the error     You need permission to perform this action      You require permission from Nathan-PC\Nathan to make changes to this file   I tried changing the permissions as explained in this guide: , but I still cannot delete the file.  I initially got this error for many/all of the files in the old Windows folder, but I read this: , and downloaded and ran the "take ownership" script. After running that command on the directory I was able to delete all but the two files above.  I have tried everything in normal mode and safe mode.  This is driving me nuts! Can anyone help me delete these two files?   Windows shall not defeat me!

Some kinda voodoo, indeed.  Bought a new boot drive, and it's time to use the old drive for data. I thought I'd save some time by just wiping the unneeded system folders, instead of backing up, formatting, and restoring. Wups!  I have a single Adobe file that absolutely will not be deleted. G:\Windows\SysWOW64\Macromed\Flash\flash9.ocx - though it may have started with a different file name. I'm able to rename it, oddly enough.  To be clear, the drive is currently plugged in externally. So I can boot the computer, plug this drive in afterward, and immediately attempt to delete. "File in use" box reads "the action can't be completed because the file is open in another program".  I'd format at this point, but it's my white whale, and I have to know if Adobe has inserted some nasty little registry hack - or whatever it is - making this impossible.  Since I'm sure it'll come up, I've taken ownership of the file - and this was the trick preventing me from deleting anything else on the drive - full rights on the file permissions, you name it, I've fiddled with the file itself.   I'm about to try uninstalling flash from the system drive, in case that aligns the planets properly. Sometimes I wish I were less stubborn, and could just format already.


Quantum mechanics is based on the idea of waves, and waves have both a magnitude and a phase? $$|\psi\rangle = i\alpha|0\rangle + \beta|1\rangle.$$ Does $\alpha$ and $\beta$ represent magnitude and $i$ represent phase? Or how do we represent phase? Or is it something else?

Quantum algorithms frequently use bra-ket notation in their description. What do all of these brackets and vertical lines mean? For example: $|ψ⟩=α|0⟩+β|1⟩$  While this is arguably a question about mathematics, this type of notation appears to be used frequently when dealing with quantum computation specifically. I'm not sure I have ever seen it used in any other contexts.     Edit  By the last part, I mean that it is possible to denote vectors and inner products using standard notation for linear algebra, and some other fields that use these objects and operators do so without the use of bra-ket notation.   This leads me to conclude that there is some difference/reason why bra-ket is especially handy for denoting quantum algorithms. It is not an assertion of fact, I meant it as an observation. "I'm not sure I have seen it used elsewhere" is not the same statement as "It is not used in any other contexts".


i have a typical web application with multi language ( french , english and Nederland ) and I'm using a page unload trigger to warn the user of unsaved changes while leaving the page/closing the tab/etc... and this works fine.  My problem is how can i change language of onbeforeunload message with title of dialogbox and the 2 bottons "leave this page" and "stay on this page" without changing language of the browser?

I need to warn users about unsaved changes before they leave a page (a pretty common problem). window.onbeforeunload = handler  This works but it raises a default dialog with an irritating standard message that wraps my own text. I need to either completely replace the standard message, so my text is clear, or (even better) replace the entire dialog with a modal dialog using jQuery. So far I have failed and I haven't found anyone else who seems to have an answer. Is it even possible? Javascript in my page: <script type="text/javascript">        window.onbeforeunload = closeIt; </script>  The closeIt() function: function closeIt() {   if (changes == "true" || files == "true")   {       return "Here you can append a custom message to the default dialog.";   } }  Using jQuery and jqModal I have tried this kind of thing (using a custom confirm dialog): $(window).beforeunload(function () {     confirm('new message: ' + this.href + ' !', this.href);     return false; });  which also doesn't work - I cannot seem to bind to the beforeunload event.


I'm trying to interpret these results of using R confint function , but I can not understand. This is a logistic regression about breast cancer. how to interpret confint function. What the 2.5% and 97.5% means?  logit1 = glm(goodmodel, data=train, family=binomial(link = logit)) summary(logit1) confint(logit1)   summary(logit1)  Call: glm(formula = goodmodel, family = binomial(link = logit), data = train)  Deviance Residuals:       Min        1Q    Median        3Q       Max   -1.76595  -0.00368  -0.00011   0.00000   2.57451    Coefficients:                           Estimate Std. Error z value Pr(>|z|)   (Intercept)             -58.106512  37.736869  -1.540   0.1236   radius_mean              -4.791077   1.933346  -2.478   0.0132 * texture_mean              0.543094   0.222894   2.437   0.0148 * compactness_mean        -93.504749  52.018859  -1.798   0.0723 . `concave points_mean`   212.367971  86.957163   2.442   0.0146 * radius_se                18.268981   7.771317   2.351   0.0187 * smoothness_se           394.202770 347.004692   1.136   0.2560   concavity_se            -78.413761  64.179173  -1.222   0.2218   `concave points_se`     -26.914245 469.938101  -0.057   0.9543   radius_worst              5.978607   4.897600   1.221   0.2222   area_worst               -0.003889   0.045800  -0.085   0.9323   concavity_worst          27.647216  14.104588   1.960   0.0500 * symmetry_worst           25.702777  15.984453   1.608   0.1078   fractal_dimension_worst  10.690937  79.071866   0.135   0.8924   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  (Dispersion parameter for binomial family taken to be 1)      Null deviance: 533.015  on 397  degrees of freedom Residual deviance:  26.608  on 384  degrees of freedom AIC: 54.608  Number of Fisher Scoring iterations: 12  > confint(logit1) Waiting for profiling to be done...                                 2.5 %        97.5 % (Intercept)             -1.482910e+02    7.95727142 radius_mean             -9.791086e+00   -1.66857433 texture_mean             1.961861e-01    1.13920334 compactness_mean        -2.299043e+02   -5.16464149 `concave points_mean`    6.027894e+01  432.99676482 radius_se                6.704669e+00   39.25468272 smoothness_se           -1.961348e+02 1307.22045246 concavity_se            -3.122203e+02   25.69408799 `concave points_se`     -1.038278e+03  891.07772306 radius_worst            -2.977840e+00   17.32103028 area_worst              -9.549641e-02    0.09462597 concavity_worst          6.661555e+00   64.03373503 symmetry_worst           1.562622e+00   63.43243116 fractal_dimension_worst -1.619176e+02  168.07512057 There were 50 or more warnings (use warnings() to see the first 50) ````

I know roughly and informally what a confidence interval is.  However, I can't seem to wrap my head around one rather important detail:  According to Wikipedia:     A confidence interval does not predict that the true value of the parameter has a particular probability of being in the confidence interval given the data actually obtained.     I've also seen similar points made in several places on this site.  A more correct definition, also from Wikipedia, is:     if confidence intervals are constructed across many separate data analyses of repeated (and possibly different) experiments, the proportion of such intervals that contain the true value of the parameter will approximately match the confidence level   Again, I've seen similar points made in several places on this site.  I don't get it.  If, under repeated experiments, the fraction of computed confidence intervals that contain the true parameter $\theta$ is $(1 - \alpha)$, then how can the probability that $\theta$ is in the confidence interval computed for the actual experiment be anything other than $(1 - \alpha)$?  I'm looking for the following in an answer:   Clarification of the distinction between the incorrect and correct definitions above. A formal, precise definition of a confidence interval that clearly shows why the first definition is wrong. A concrete example of a case where the first definition is spectacularly wrong, even if the underlying model is correct.


i've been trying to center my form & input horizontally but it doesn't work  I've tried using margin & padding but nothing works.    body {     background-color: #2F2F2F; }   /* Form (outside) */ .form-inline {     padding: 1% 0%; }  /* Input (inside) */ .form-control {     background-color: #353434;     border: #3E3E3E 2px solid;     /* Top right bottom left */      /* Align the writing in the center*/     text-align: center; }   /* Search text */ .form-control::placeholder {     color: #AEAEAE;     text-align: center; } <header>     <!-- Search inputForm -->     <div class="container">         <form class="form-inline my-2 my-lg-0" action="#POST">             <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">         </form>     </div> </header>

How can I horizontally center a
 within another
 using CSS?

Foo foo


The  gives a good explanation of the magnetic field of the Earth: the Coriolis force focus inner currents into current spirals generating magnetic(s) field(s).  What I'm trying to understand is the origin of these inner currents.  For currents to appear, there should exist charges moving. If such important charges exist, there is one or many mechanisms at work to separate positive and negative ions. Of course among these mechanisms a magnetic field acting on currents is a pretty good explanation (see : a magnetic field on a rotating conducting fluid is able to create currents and these currents in turn will create a magnetic field). But at the same time this loop between cause and effect isn't completely satisfying and should have been started in an external way.  What might have started an unbalance in positive and negative ions inside Earth to bootstrap inner currents and then its magnetic field?  What process might explain the starting of the magnetic field of the Earth without the hypothesis this magnetic field was already there?

I saw on Discovery channel that the source of Earth's magnetic field is the molten iron and metals in the earth's core. The spinning of these liquid metals produces the same effect as electric current in a coil which produces a magnetic field. The scientist in the program proved the concept by conducting an experiment where a big metal sphere where winded by a metallic tube in which molten Sodium was pumped so it circulate around the sphere in a similar way that happens inside earth. The experiment showed that a magnetic field was successfully produced.  My question is :  How could a circulating neutrally charged particles produce a magnetic field?  It is like having two electric currents one due to the negative charges (electrons) and the other is due to positive charges (nucleus) with same value and in opposite direction so there should not be a magnetic field. so how does this happen?


I am trying to make a JButton that displays an image in the JPanel when pressed - allowing the user to choose the location in the panel. I am using the following methods to paint:  public void paint(Graphics g, URL path) {     Image img = getImage(path);     Graphics2D g2 = (Graphics2D)g;     g2.drawImage(img, getX(),getY(),50,50, null); }  public Image getImage(URL path) {     Image temp = null;     try     {         temp = Toolkit.getDefaultToolkit().getImage(path);     } catch (Exception e) {         e.printStackTrace();     }     return temp; }   When I call paint(), I get a null pointer exception in my last line of my ActionListener:  dogButton.addActionListener(new ActionListener() {         public void actionPerformed(ActionEvent ae) {             Graphics g = null;             Animal animal = new Animal();             animal.paint(g, main.class.getResource("/Animals/dog.jpg"));         }   I'm a little confused overall about how to use ActionListeners.  This is my first project so I apologize for my lack of knowledge.

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?


Is there a way to see which badges a user lacks. In particular I wonder if Jon Skeet does not have any badge.  P.S. If such a function does not exist, a nice feature would be be able to see the ../help/badges page for any particular user with ticks next to the badges they have.

When I go  I see a pretty, 'at-a-glance', alphabetically ordered, list of badges with my badges checked. Can I see this checklist for other users?  If not, do you think it's worth implementing? Consider that the list of badges at the bottom of the user page is not a good summary view and doesn't allow you to quickly see which badges the person does or does not have.


Let $I = \{a+ ib \in \Bbb Z[i] : 2 \mid a-b\}$ then $I$ is a maximal ideal of $ \Bbb Z[i]$.  We consider an ideal $J$ such that $I \subset J\subset\Bbb Z[i] $. So there exists an element $p \in J$ but not in $I$. Note that $a \not\mid a-b$ when $a,b$ are of odd parity i.e. one is odd and other is even. Without loss of generality we assume that $p = c+ id$ where $c$ is odd and $d$ is even. Then we have $q = (c-1)+id \in I$ since both $c-1,d$ are even and hence $q = (c-1)+id \in J$. Now since $J$ is an ideal, so $p-q = 1 \in J$. Thus $J =\Bbb Z[i] $.   Hence $I$ is a maximal ideal of $ \Bbb Z[i]$.  Is the proof correct??

I'm making some exercises to prepare for my ring theory exam:     Prove that $I= \{a+bi \in ℤ[i] : a≡b \pmod{2}\}$ is an maximal ideal   of $ℤ[i]$.   I know that $a+2l=b$ with $l\in ℤ$ (or should I say $l \in ℤ[i]$)? Therefore I can write $a+(a+2l)i=a+ai+2li$. So I don't have $0+i$ in my ideal. For even real parts I have even complex parts, and for odd real parts I have odd complex parts. But I don't see what I can conclude now.


Question:  Does it matter if some links are full URL:  ie: http://example.com/contact-us.html (absolute) versus relative (example.com/contact-us.html) for SEO purposes? The difference is when using absolute it includes the full http:// part versus relative doesn't include it in the link when viewing source.  I have a site that has a submission form that I would like to serve up via SSL / HTTPS. The issue is that when I force (via .htaccess) for this particular submission form page to SSL / HTTPS only then all of the links on the page are to HTTPS. For example, the main navigation bar on all pages of the site and what is indexed by search engines is HTTP only. On this one HTTPS page it shows all of the other navigation links as HTTPS because I used relative links in the HTML (ie: /contact-us.html). I don't want search engines to index HTTP and HTTPS versions of all of the same pages (identical indexing).  I have updated the main navigation section to do absolute links (ie: www.example.com/contact-us.html) however, I noticed when I looked in the source it will reflect the whole www.example.com/page-name.html section but on other relative links that I didn't make absolute it will only reflect the /page-name.html.  Will this matter for SEO purposes that some links on the page show the domain's www.example.com/page-name.html while some links are relative /page-name.html? If you look at the source of any page the navigation is now all absolute and any content, paragraph, etc related links are all relative.   Does this matter SEO-wise? If so, what is the work around? Go through the source of ALL pages and make them absolute?

Am developing a website, I have used many anchor link in menu navigation and given absolute URL. Somewhere I read we can also use relatives URL in menu navigation.  From SEO point of view, which is better for menu navigation absolute or relative URLs?


Resident Evil 2 remake highlights the key items which have no longer use in the game and allows deleting them from the inventory. Does RE7 have any similar system? I don't know if the various "animal-branded" keys have been used in all locks, and the inventory space is limited even after the backback upgrade (+4 slots)...

As with many resident evil games, you sometimes needs to collect certain keys to open certain doors, and resident evil 7 has plenty of these around.  Some keys are clearly single use, and get left in the lock in which you use them. However, there are a number of keys that can be used on multiple doors. For example, the Scorpion Key.  I am concerned that I might end up carrying these around needlessly and using up valuable inventory space, so...  Do these multi-use keys get discarded when you use them on all the doors they apply to? Or do you get a warning saying the key is no longer needed? (like previous games are known to do)


I am learning about the basics of Linux and archiving/compressing TAR files i have stumbled across tar -xvf and was wondering what it does. I have checked the man pages and know that x means extract and v means verbose but what does f do?

I am receiving this error message when I'm trying to uncompress a .tgz archive:  $ tar -zxvf OVM_EL5U3_X86_EBIZ12.1.1_DB_VIS_PVM.tgz.1 gzip: stdin: not in gzip format tar: Child returned status 1 tar: Error is not recoverable: exiting now   As you can see, the file name ends with .tgz.1.  When the file name is .tgz.0 it will be uncompressed with no error by the tar -zxvf command.


The story was about a robot/android made of brass and powered by air. His entire world, all the people in it, was built the same way. He was fascinated by their brain analog which, by self-examination and experimentation, he discovers is a complex set of tiny, thin brass wafers with patterns on them that constantly moved and intermeshed due to air pressure. All of the beings in this world needed to recharge their air pressure or they would die. The space below their world is a large pressurized air bladder that is slowing equalizing with the upper world.

I read a short story sometimes ago on Reddit, it really stuck with me but I cannot find it anymore.  The story is told by a sentient being in a universe where people have to fill their lungs in some sort of air fountains and everything in this world is powered by air.  The narrator realize at some point that the pressure difference between the reservoir and the atmosphere is decreasing and they all will eventually die or stop moving due to this. It is an allegory on the eventual death of the universe due to increasing entropy.  Does anyone know what this is?


I keep getting the 'good bye' response no matter what I enter, 'yes' or 'no'. How would I change that so responses are correct.  import java.util.Scanner;  public class SimpleQuiz1 {   public static void main(String[] args){      Scanner userInputScanner = new Scanner (System.in);      System.out.println("Are you ready to take this NBA quiz?");     String answer = userInputScanner.nextLine();      if(        answer == ("yes")){     System.out.println("Then lets get started!!!");      } else{         answer = ("no");       System.out.println("Goodbye, come again soon!");       }     }   }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I am trying to create a an image of an object (say a cube) and its shadow, with any other pixel except for the object and shadow being transparent, in Blender 2.7. I need this since I will place the resulting images next to several others in Photoshop later, and also as standalones, in a scientific paper which requires that all images have a transparent background.   I know this question has been asked many times before, but all the answers I found are lacking, namely:  is similar, but the answer uses a "shadow" output of the layer which I couldn't find (I assume it doesn't exist in 2.7?). On the other hand,  gives a nice solution in case you are trying to place your objects + shadows on top of an existing image by multiplying outputs, but does not produce an image with a transparent background, and I don't see a way to modify it easily.

I am trying to render an animation in cycles without the background. However, every time I have it render, the background still shows up.  I used the compositor to add a background image so I can animate the object around the background. I set the output to RGBA and set the film to transparent.   Now I want to use it in After effects and I simply want to export/render it without the background and make it transparent.  How do I do that?


How can I have my Windows 8 system recognize the .ht file extension to launch a hyper terminal app?  I am using an HP Envy tablet.

How can I change or set the default application for handling a given file type? What about for some specified actions, like "open web browser" and "preview image"?


I've got a database with 3 Filegroups and each filegroups own a single file, Filegroup names are Primary, SecondFG and ThirdFG. I want to backup ThirdFG separately each time without backing up the others. I've tried it in many ways but when I want to restore database filegroup backup I get the error for other Filegroups or files are not included in the backup file! but When I backup all FileGroups together there would be no problem, please guide me how to backup and restore single filegroup, by the way I've read all BOL and I couldn't solve my problem!

I have a task: I have created a database with a filegroup lamb that has a few tables.  I need to extract a csv into a table in a filegroup named lamb and back up that filegroup.  Then extract another csv file again and back up again.  But I need to be able to restore the first backup.  What is the backup and restore method? Is it possible to restore only the lamb filegroup?


This is what I'm trying to do but my code is either not compiling or giving me an unexpected output "BC" instead of just "B".  #include <stdio.h>  void removeFirstAndLastChar(char** string) {     *string += 1; // Removes the first character     int i = 0;     for (; *string[i] != '\0'; i++);     *string[i - 1] = '\0'; }  int main(void) {     char* title = "ABC";     removeFirstAndLastChar(&title);     printf("%s", title);     // Expected output: B     return 0; }   I looked through a lot of answers here related to passing pointers by reference but none of them seemed to contain the operations that I want to do in my removeFirstAndLastChar() function.

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


I have proved this for prime $n$.     I need help to prove $2^n-1$ is composite when $n$ composite     As far I can think - suppose $2^n-1$ is composite but $n$ is prime.  $\\$  Therefore, $1$ divides $$2^n-1=(2-1)(2^{n-1}+2^{n-2}+....+2+1)$$ which means $2^n-1$ is divisible by $1$ and the number itself. Hence $2^{n-1}+2^{n-2}+...+2+1>1$ and it cannot be represented as the product of its factors. Hence $2^n-1$ is prime - a contradiction, hence $n$ is composite.    Am I correct here? I need help. Any help is appreciated.

Not sure if I'm doing this correctly but this is what I've done:  Assume that $n$ is composite and suppose $2^n-1$ is a prime for $n \gt 2$. Then, $2^n-1 = 2k$ for some $k \in \Bbb Z $, $\forall n$.  But this would be a contradiction since $n \gt 2$.  I'm not sure if this a correct proof.  EDIT: I realized that it's to prove $2^n - 1$ NOT $2^{n-1}$ so my attempt above is completely wrong.


Let $\zeta_n$ be the $n$th .  The wikipedia page for  (UFD) states that for $n \in \mathbb Z$, $1 \le n \le 22$, $\mathbb Z[\zeta_n]$ is a UFD, but not for $n = 23$.  Is there a general formula for determining when an integer extension with a root of unity is a UFD?  Failing that, is it known for higher $n$ than $23$?

When is $\Bbb{Z[\zeta_n]}$ a PID?  I was just wondering if $\Bbb{Z[\zeta_n]}$ is PID or not where $\zeta_n$ is $n$th primitive root of unity for arbitrary positive $n$


The axiom of Replacement Scheme implies separate axiom. I can not show this lemma. Does someone have any idea about it?

I hope to show that the comprehension axioms follows from the replacement schema.  This is a solution that professor wrote.  $P(u,u)$: every set $u$, exists an unique $u$ such that $\psi(u)$.  Then exist a set $y=\{u:P(u,u) \text{ and } u \in X\}$  Let $F=\{(u,u) : \psi(u)\}$. Then $F(X) \in u$ and $y=\{u \in F(x) : \psi(u)\}$  I took some notes but I think that there are much errors.  Thanks in advance.


I am a Philippine passport holder and I'm planning to travel to St Vincent and the Grenadines this month. Do I need to get a transit visa during my layover at Toronto and Port of Spain?

I'm traveling to India from the US, I've a F1 visa in the US and I'm an Indian national. My flight is through YYZ (Toronto Pearson International Airport), a layover more than an hour there.  Do I need to get a transit visa?


In Manim (The 3b1b programming language to do animations) we can get some beautiful animations where the background is black, can we do it in LaTeX using Tikz? Here's an example: I want to draw this figure but with a black background. \begin{tikzpicture}[ point/.style={circle,fill,inner sep=1.3pt}] \draw[thin, dashed, black!50!] (0,0) -- (8,0); \begin{scope}[rotate around={15:(8:0)}] \draw[thin, black] (0,0) -- (8,0); \draw[fill, gray!40] (2,0) rectangle (4,1); \draw[black] (2,0) rectangle (4,1); \draw (3,0.5) node{$\bullet$}node[above,right]{$G$}; \draw[dashed, black] (3,0) -- (3,3); \draw[thick, black, ->] (3,0) -- (2.4,1.5) node[above]{$\vec{R}$};  \coordinate(y) at (3,0); \coordinate(x) at (3,1.5); \coordinate(z) at (2.6,1); \pic [draw=black!15!black,text=black,angle radius=9mm,"$\varphi$",angle eccentricity=1.3, ->]{angle = x--y--z}; \end{scope}  \draw[thick, black,->] (2.86,1)--(2.86,0) node[above,right]{$\vec{P}$}; \coordinate(o) at (0,0); \coordinate(i) at (2,0.5); \coordinate(j) at (2,0); \pic [draw=black!15!black,text=black,angle radius=9mm,"$\alpha$",angle eccentricity=1.3, ->]{angle = j--o--i};         \end{tikzpicture}   Or plotting a function as an example Gamma function:  Here's the code from an answer: \begin{tikzpicture}[]  \begin{axis}[ xmin = -4.9, xmax = 5.1,  %ymin = -3.5, ymax = 3.5,   restrict y to domain=-6:6, axis lines = middle, axis line style={-latex},   xlabel={$x$},  ylabel={$y$}, %enlarge x limits={upper={val=0.2}}, enlarge y limits=0.05, x label style={at={(ticklabel* cs:1.00)}, inner sep=5pt, anchor=north}, y label style={at={(ticklabel* cs:1.00)}, inner sep=2pt, anchor=south east}, ]  \addplot[color=red, samples=222, smooth,  domain = 0:5] gnuplot{gamma(x)};  \foreach[evaluate={\N=\n-1}] \n in {0,...,-5}{% \addplot[color=red, samples=555, smooth,   domain = \n:\N] gnuplot{gamma(x)}; % \addplot [domain=-6:6, samples=2, densely dashed, thin] (\N, x); }% \end{axis} \end{tikzpicture}  Is there any method to make these figures with a black background "Dark theme"?

How to change the paper color(background color) in tikz class kindly help me to change color    \documentclass{scrartcl} \usepackage[usenames,x11names,dvipsnames,svgnames]{xcolor} \usepackage{graphicx,amsmath,latexsym,amssymb,amsthm,geometry} \usepackage{tikz} \usepackage{pagecolor}% http://ctan.org/pkg/{pagecolor,lipsum} \usetikzlibrary{decorations, decorations.text} % tight page \usepackage[active,tightpage]{preview} \PreviewEnvironment{tikzpicture} % \begin{document}%  \begin{tikzpicture}         % outer circle             \draw[line width=2 mm,color=black,fill=white!10] circle[radius=7cm];         % outer text             \path[                 postaction={                     decoration={raise=.1ex,                         text along path,                         text format delimiters={|}{|},                         text={%                             |\Huge\bfseries\color{black}|                           name name {\textbullet} name {\textbullet} name name name name name                         },                         text align=fit to path,                         reverse path                     },                     decorate                 }             ]              (0:6.2cm) arc (0:360:6.2cm); \draw[line width=2 mm,color=black,fill=white!10] circle[radius=5.8cm]; % central text \node[color=Brown3] at (0, 1){\includegraphics[width=4.5cm]{14}}; \end{tikzpicture}% \end{document}


This is the question.  Let $\gcd(m,n)=d$. Show that if $a=b$ (mod $d$), the equations $x=a$ (mod $m$) and $x =b$ (mod $n$) has a solution.  My thinking is this. Because $\gcd(m,n)=d$, there exists some $r,s$ integers such that $rm+sn = d$. So $r\frac{m}{d} + s\frac{n}{d} = 1$. Now, my idea is to define $x$ similar to that in the Chinese Remainder Theorem, letting $x = br\frac{m}{d} + as\frac{n}{d} \implies dx = brm+asn$. Now, $dx$ (mod $m$) $= asn = da$ (mod $m$). Similarly $dx= db$ (mod $n$). So $dx = da$ (mod $m$) = $db$ (mod $n$). Here is where I'm stuck. I suppose now I should use the fact that if $a=b$ (mod $d$), then $dx = da$ (mod $m$) = $db$ (mod $n$) would imply $x=a$ (mod $m$) and $x =b$ (mod $n$), and the proposed $x$ above would work. But how do I do it? Any hints?

How to prove that a congruence system with $n$ equations can be solved if and only if all the equations can be solved two by two?  \begin{cases} x \equiv a_1 \phantom ((mod\phantom mm_1) \\ x \equiv a_2 \phantom ((mod\phantom mm_2) \\ ... \\ x \equiv a_n \phantom ((mod\phantom mm_n) \end{cases}  I know that if $n=2$, the system can be solved if and only if $\gcd(m_1,m_2)\mid a_1-a_2$.  The thesis is: the system is solvable $\Longleftrightarrow$ $\gcd(m_i,m_j)|\mid a_i-a_j$ for all $i\neq j$.


I am trying to install VirtualBox Guest Additions for guest Kali Rolling.  I get the following outputs:  $ uname -r 4.9.0-kali3-amd64  $ dpkg -l | grep linux-headers ii  linux-headers-4.9.0-kali4-all             4.9.30-2kali1                        amd64        All header files for Linux 4.9 (meta-package) ii  linux-headers-4.9.0-kali4-all-amd64       4.9.30-2kali1                        amd64        All header files for Linux 4.9 (meta-package) ii  linux-headers-4.9.0-kali4-amd64           4.9.30-2kali1                        amd64        Header files for Linux 4.9.0-kali4-amd64 ii  linux-headers-4.9.0-kali4-common          4.9.30-2kali1                        all          Common header files for Linux 4.9.0-kali4 ii  linux-headers-4.9.0-kali4-common-rt       4.9.30-2kali1                        all          Common header files for Linux 4.9.0-kali4-rt ii  linux-headers-4.9.0-kali4-rt-amd64        4.9.30-2kali1                        amd64        Header files for Linux 4.9.0-kali4-rt-amd64 ii  linux-headers-amd64                       4.9+80+kali1                         amd64        Header files for Linux amd64 configuration (meta-package)   Why do the kernel versions (4.9.0-kali3-amd64 vs 4.9.0-kali4-...) differ and what can I do about it?    SOLUTION  Since question is closed I can't add answers. So I'm adding the solution here.  I tried solutions from the duplicate questions, but they didn't work. Instead, I found  which basically suggests following.  Check kernel version:  $ uname -a Linux kali2017 4.9.0-kali3-amd64 ...   Currently it contains kali3. Install following packages:  $ apt-get update $ apt-get install linux-headers-amd64 $ apt-get install linux-image-4.9.0-kali4-amd64   Reboot and check kernel version once again:  $ reboot $ uname -a Linux kali2017 4.9.0-kali4-amd64 ...   Voila, kali4! Now, install guest additions:  $ apt-get install virtualbox-guest-x11   Done.

apt-get install linux-headers-`uname -r` Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package linux-headers-4.9.0-kali3-amd64 E: Couldn't find any package by glob 'linux-headers-4.9.0-kali3-amd64' E: Couldn't find any package by regex 'linux-headers-4.9.0-kali3-amd64'


This is a long winded question so bear with me!   I am trying to upgrade my 12.10 Quental Ubuntu to the 14.04 version. This has led to a problem within my system not being able to update. For information, this build of Ubuntu does a dual-boot with my Windows 7 package.  I initially tried to find the update manager on my system which has dissapeared. I then searched on Google and came to this page:    When typing in sudo apt-get update, it hits 18% and says, "Waiting for headers."  A couple of errors occur. The last two lines of the error log state:  "W: Failed to fetch   404  Not Found [IP: 91.189.91.13 80]  E: Some index files failed to download. They have been ignored, or old ones used instead."  I have checked online and found this page in answer to this problem:    During the main answer it suggests to type these three lines into the command line:  sudo add-apt-repository ppa:fossfreedom/packagefixes  sudo apt-get update  sudo apt-get install banish404  After I run sudo banish404, I still get the same error message.  My final aim is to just update Ubuntu to 14.04 in my Dual boot machine. My fear is if I download an ISO and try to run it from booting my machine, it will either wipe everything, (and there is a lot of stuff within my Windows account!) or provide a triple boot scenario whereby I choose between Windows, Ubuntu 12.10 and Ubuntu 14.04.  My experience is very limited with Linux and the command line, (did a short course a couple of years ago with my uni.) Although it has increased a lot in the last two days, (I have created to a Kali Linux virtual machine and a SIFT forensics virtual machine, both in virtual box on my windows account.)  Any help?

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


A pixel diagram is a way to visualize a graph, or even the non-zero entries in a matrix.  It is typically used to help visualize . I am trying to use Tikz to draw these diagrams.  An example can be seen below (taken from )    So the idea is as follows: for a square n x n matrix, draw an n x n grid, and make the i-jth pixel black if the i-jth element of the matrix is non-zero (or there is an edge between nodes i and j).  Is it possible to enter a data file containing the matrix data and have tikz generate the pixel diagram?  I am very much a tikz novice and don't even know where to begin here...  thanks!

Can you create images like this:    when you have something like  0 = green (#54ff00) 1 = white (#ffffff) 2 = red   (#ff0000) 3 = blue  (#0048ff)  Image (Python list of integers defined above): [[2,0,0,0,0,0,0],  [0,3,0,0,0,0,0],  [0,3,2,1,1,0,0],  [0,3,2,2,2,1,1],  [0,3,2,0,0,1,0],  [0,0,0,0,0,1,0],  [0,0,0,0,0,1,0]]   with TikZ?  How far I got  The following MWE defines all colors, produces a grid of the correct size (though the size is determined by hand):  \documentclass[varwidth=true, border=2pt]{standalone} \usepackage{tikz} \usepackage{xcolor}  \begin{document}     \newcommand\n{7}     \definecolor{green}{HTML}{54FF00}     \definecolor{wite}{HTML}{FFFFFF}     \definecolor{red}{HTML}{FF0000}     \definecolor{blue}{HTML}{0048FF}     \begin{tikzpicture}         \foreach \x in {1,...,\n}{             \foreach \y in {1,...,\n}{                 \begin{scope}[shift={(\x,\y)}]                   \draw [fill=green] (0,0) rectangle (1,1);                 \end{scope}             }         }     \end{tikzpicture} \end{document}   Of course, I could simpy make a lot of adjusted                   \begin{scope}[shift={(\x,\y)}]                   \draw [fill=green] (0,0) rectangle (1,1);                 \end{scope}   but I've wondered if this can (with reasonable effort) be done in TikZ / LaTeX.  My problem is giving TikZ the color array. I don't have any idea how to do this. I only know two types of looks in TikZ:  \foreach \x in {0,1,2,3,4,5}{...} \foreach \number in {1,...,\n}{...}   I have never seen a nested over a 2D-array. All I have seen so far were 1D-Arrays of tuples (with fixed tuple size).


Given $x,y,z$ is positive number that $x+y+z=1$. Prove that $$ P = \frac{x}{y^3+2xyz} + \frac{y}{z^3+2xyz} + \frac{z}{x^3+2xyz} \gt \frac{15}{2}$$ My attempt: $$2xyz \leq \frac{2}{27}$$ $$ \Rightarrow P= \frac{x}{y^3+2xyz} + \frac{y}{z^3+2xyz} + \frac{z}{x^3+2xyz} \geq \frac{x}{y^3+\frac{2}{27}} + \frac{y}{z^3+\frac{2}{27}} + \frac{z}{x^3+\frac{2}{27}} $$ $$ \Leftrightarrow P \geq \frac{27}{2} (x+y+z) - \frac{27}{2}\left(\frac{x\cdot y^3}{y^3+\frac{2}{27}} + \frac{y\cdot z^3}{z^3+\frac{2}{27}} + \frac{z\cdot x^3}{x^3+\frac{2}{27}}\right)$$ AM-GM: $$y^3+\frac{2}{27}=y^3+\frac{1}{27}+\frac{1}{27}\geq 3\cdot\sqrt[3]{y^3\cdot\frac{1}{27}\cdot\frac{1}{27}}=\frac{y}{3}$$ Similar we have $$\frac{27}{2}\left(\frac{x\cdot y^3}{y^3+\frac{2}{27}} + \frac{y\cdot z^3}{z^3+\frac{2}{27}} + \frac{z\cdot x^3}{x^3+\frac{2}{27}}\right) \leq \frac{81}{2}\left(xy^2+yz^2+zx^2\right)$$ $$\Leftrightarrow P \geq \frac{27}{2} - \frac{81}{2}\left(xy^2+yz^2+zx^2\right)$$ Now we need prove $$\frac{81}{2}\left(xy^2+yz^2+zx^2\right)\lt \frac{27}{2} -\frac{15}{2} = 6$$ $$\Leftrightarrow xy^2+yz^2+zx^2 < \frac{4}{27}$$ I was stuck here. Help me, thank you so much.

Prove that, for all positive real numbers $x$, $y$ and $z$, $$4(x + y + z)^3 > 27(x^2y + y^2z + z^2x)$$  I've tried expressing it as a sum of squares, but haven't got anywhere.   Hints are also welcome.


I want to change the color of the interior cup but I can't seem to do it without the image texture being deleted when I attempt to transition from image texture to color. Even after the material gets duplicated.

How do you add more than one material to a mesh?   I have tried adding two materials to the object, and then assigning one of the materials to a vertex-group, but I could not find a place to assign it.  I am making a striped bouncy ball that I want to deform, so adding a different material by separating the mesh into different objects would not be ideal.


My problem is that when I try to substract the K from the shape by using the Shape builder tool, it messes up the gradient on the shape. How can I manage to keep the gradient as it is but also avoid this very little line.    This is the expected result, but the K is actually white (not transparent) and also, there is a very thin circle line when the K intersect with the circle borders.    You can see here the very thin line.    This is the K which is used to substract with shape builder tool. To do so, I make sure that both K and shape are not grouped, and then I click on the tool and click on the K    This is the result of the substraction. As you can see, the gradient is completely messed up compared to how it was before.  The requirement is also that we need that to stay a vector.

I have two separate objects that I have applied gradient fill to.  The gradient fill seems to only apply to the objects as individuals. I tried grouping the shapes, but that doesn't seem to change the gradient.    How do I get one gradient to cover all my shapes?


I am beginner for web development and i am trying to align below p element center vertically but its not working can some one help me please      <meta charset="utf-8">   <meta name="viewport" content="width=device-width, initial-scale=1">   <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css">

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I want to center a div vertically with CSS. I don't want tables or JavaScript, but only pure CSS. I found some solutions, but all of them are missing Internet Explorer 6 support.
Div to be aligned vertically
   How can I center a div vertically in all major browsers, including Internet Explorer 6?


Prove by Induction that: $$(n+1)(n+2)(n+3)(n+4)(n+5)$$ is divisible by 120. I tried to solve it, but could do so only till the inductive step. I assumed: $$p(k)=(k+1)(k+2)(k+3)(k+4)(k+5), and $$ $$p(k+1)=(k+2)(k+3)...(k+6)$$ Then, I distributed it as: $$p(k+1)=(k+2)(k+3)...(k+5)(k+1+5) \\=(k+1)(k+2)...(k+5)+5(k+2)(k+3)...(k+5)\\=p(k)+5(k+2)(k+3)...(k+5).$$ I got stuck over here. Am I right till here? Can someone tell what to do next?

How can we prove, without using the properties of binomial coefficients, the product of $n$ consecutive integers is divisible by $n$ factorial?


The time(1) command allows you to time any command, by passing it as arguments to time.  I know it's possible to redirect stderr and stdout to a file via 2>&1, and there's also tee(1) which allows one to copy its input to both the screen and a file.  However, I do not know how to add timestamps to logs.   Is there a tool to redirect stderr and stdout to a file, AND append timestamps to it for logging purposes?

I wish to prepend a timestamp to each line of output from a command. For example:  foo bar baz   would become  [2011-12-13 12:20:38] foo [2011-12-13 12:21:32] bar [2011-12-13 12:22:20] baz   ...where the time being prefixed is the time at which the line was printed. How can I achieve this?


I am interested to see a list of all questions that were closed because being a dup of another question.  I strongly want to research a particular question and reading all the answers inside the dups will help me a lot.  Is there such feature? if not, this is a feature request

Can I see how many duplicates there are of a post? I.e. how many posts have been labelled as duplicate because of this post? If so, how? And can I also get a list of these duplicated posts?


"Thermal expansion arises from the asymmetrical nature of potential   energy curve for atoms in a solid. If oscillators were truly harmonic   separation would not change regardless of the amplitude of vibration."   I don't understand how a temperature increase might not affect the volume of a solid substance if the oscillations were harmonic?

I came upon the following question:  A solid expands on heating because: a) the potential energy of interaction between atoms in the solid is asymmetric about the equilibrium positions of atoms; or b) the frequency of vibrations of atoms increases.  My attempt: I did not make a huge deal out of the question, and simply thought that it is due to the increase in frequency of vibrations, which now causes greater oscillations about the lattice points, which in turn increases the average volume occupied by atoms, leading to expansion. However the answer is a). Can someone explain, possibly using some model (like the spring-particle model of the lattice), why this is so, and why b) is NOT a cause of expansion?


Question  Candidates were asked to come to an interview with $3$ pens each. Black, blue, green and red were the permitted pen colours that the candidate could bring. The probability that a candidate comes with all $3$ pens having the same color is _________.  My Approach $\binom{4}{1}$ to select 1 colors from $4$ available colors and then probability of each color $ =\frac{1}{4}$ Reqd probability$  =4 \times (\frac{1}{4} )^{3}$ is it correct?

Question I know this is a duplicate of , i am still posting it because i want to know flaw in my approach.  Candidates were asked to come to an interview with $3$ pens each. Black, blue, green and red were the permitted pen colours that the candidate could bring. The probability that a candidate comes with all $3$ pens having the same colour is  $?$  My Approach Let $E=\text{chossing all three pen of same colour}=\binom{4}{3} \times 1 \times 1 \times 1=4$ i.e select which colour among red,blue,green and black and then there will be only $1$ choice Let $F=\text{possible way of selecting 3 pen}=4 \times 4 \times 4$ As there are $4$ ways to select colour of the pen and we have to choose for $3$ pens. Hence reqd probability$$=\frac{E}{F}$$ $$=\frac{4}{4 \times 4 \times 4}=\frac{1}{16}=0.0625$$ Where am i wrong? Please help!


Let $1,2,3,4,5,6,7,8,9,11,12,\cdots$ be the sequence of all the positive integers which do not contain the digit zero. Write $\{a_n\}$ for this sequence. By comparing with a geometric series, show that  $$\sum_n \frac{1}{a_n}\lt90$$  I would try to start this but summing the geometric series is trivial, so the point lies in finding such a series(or a set of series)  This looks really amazing to me since this is just the harmonic series, with (apparently) a small fraction of the terms removed, and yet it converges.

I know that the harmonic series $1 + \frac12 + \frac13 + \frac14 + \cdots$ diverges. I also know that the sum of the inverse of prime numbers $\frac12 + \frac13 + \frac15 + \frac17 + \frac1{11} + \cdots$ diverges too, even if really slowly since it's $O(\log \log n)$.  But I think I read that if we consider the numbers whose decimal representation does not have a certain digit (say, 7) and sum the inverse of these numbers, the sum is finite (usually between 19 and 20, it depends from the missing digit). Does anybody know the result, and some way to prove that the sum is finite?


This is probably something I should already know, but I would like to know an intuitive way to think about the partial x, partial y derivative of $f$. I understand that $\frac{\partial ^2 f}{\partial x^2} $ can be understood as the concavity in the x-direction. Is there a similar way of thinking about $\frac{\partial^2 f}{\partial x \partial y}$?

Are there any geometric interpretation for the second partial derivative? i.e.  $$f_{xy} = \frac {\partial^2 f} {\partial x \partial y}$$  In particular, I'm trying to understand the determinant from  for determining whether a critical point is a minima/maxima/saddle points:  $$D(a, b) = f_{xx}(a,b) f_{yy}(a,b) - f_{xy}(a,b)^2$$  I have no trouble understanding $f_{xx}(x,y)$ and $f_{yy}(x,y)$ as the of measure of concavity/convexity of f in the direction of x and y axis. But what does $f_{xy}(x,y)$ means?


Hello! I am a Blender 2.8 beginner. I want that little sphere at the back to act like a Sun and light up some of the background, kind of like this:  But I have no idea how to achieve that. Can somebody please help me? Also, any other advice or criticism is welcome. Thank you

How do I turn the little emission sphere into a realistic flaring sun. (This piece is animated with all the planets rotating and revolving)


I am trying to run the following code in order to input an array of any size I desire: import java.util.Scanner; import java.util.Arrays;  public class testing2 {      public static void main(String[] args) {                  double[] inputs = new double[5];         int currentSize = 0;                  System.out.println("Please enter values, Q to quit:");         Scanner in = new Scanner(System.in);                  while (in.hasNextDouble())         {             if (currentSize >= inputs.length)            {               inputs = Arrays.copyOf(inputs, 2 * inputs.length);            }                       inputs[currentSize] = in.nextDouble();            currentSize++;         }         inputs = Arrays.copyOf(inputs, currentSize);                  System.out.print(inputs);      }  }  But when I input any array, my output is just a combination of symbols such as: [D@13fee20c, and this is not the output I am hoping for. Could anyone help me?

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


I know this question has been asked a lot, but I still don't fully understand the difference between Present Perfect and Present Perfect Continuous (if there is one).     Sometimes the two tenses are interchangeable[...]. But sometimes they are not. Essentially, it depends on whether the action denoted by the verb is regarded by the speaker as completable or not. By this definition, living and learning, for example, are not completable, in which case both tenses are possible:   -I have been living in London since 2001.   -I have lived in London since 2001.   Is one of these tense carrying more sense regarding the fact that I am/am not currently living in London?     It has been 13 years I am living in London   Is it grammatically correct? If yes, would it be closer to Present Perfect or Present Perfect Continuous? Does this mean that I am still living in London?

I have studied "present perfect" and "present perfect continuous" for a week. I know forms, verb and helping verb I should use when I write them.  For me, they have nearly same definition because I can use them interchangeably in Thai language. (My native language)  For example, the sentences        I have learned English language in the past few weeks.    I have been learning English language in the past few weeks.       have no difference in meaning to me. They both mean "I began learning the English language in the past and I am still learning it"  Can I use them interchangeably in English? Or is there any difference between them? For example, when should I use present perfect but not present perfect continuous?