I made an animation using the cycles renderer but the end animation is jittery, and I don't know why. I've attached the final video file link here. I'm using the latest 2.92 version of blender

I've made a simple animation in blender 2.81a and am now trying to render it.    My system specs: CPU i7-6500U; GPU Nvidia Geforce GTX 950M; RAM 16gb DDR4 So far, I've done two test renders (both in cycles):   8 samples, 8 light bounces, denoising on, 60fps (240 frames). Total render time was about 3 hours. Looking at single frames, they were flawless, but if you play the animation, you see that the denoiser is producing some kind of jitter (like in ). 256 samples, 4 light bounces, denoising on. I set the framerate to 24fps and used time remapping to maintain animation speed (96 frames). The jitter has become far less, but is still there. However, the time remapping made the animation look kind of not-fluent. So I figured that I probably need 512 samples to reduce the jitter and render at 60fps. However, this will probably take about 16 hours to render. Are there any other ways to   change the framerate without changing the animation speed? (except for manually repositioning keyframes) decrease general render time/reduce the jitter (aka denoising for animations) Thanks in advance!     Edit: I heard that Blender 2.83 and 2.90 (which is not yet oficially released) have improved the denoising system, e.g. AI-accellerated denoise, adaptive sampling and optix viewport denoising. Do any of these also apply to video or is there now any option for better denoising for animations?


Let $a_n$ be a sequence of real numbers and let:  $$\lim_{n \to \infty}(a_{n+1}-a_n)=0$$ Prove that every $a \in (\lim\text{inf}\,a_n, \lim\text{sup}\,a_n)$ is a limit point of $a_n$.

Prove that if a sequence satisfies $\lim\limits_{n\to\infty}|a_{n+1} - a_n|=0$ then the set of its limit points is connected.   My professor once mentioned a proposition likewise but I cannot find the exact version of it. Can anyone help?


Is there any way to disable below warning that Chrome throws sometimes when you are trying to close a tab?

Is there a way to disable the Are you sure you want to leave this page? message on a website? I'm using Chrome.


I noticed a bug/feature with the syntax highlighting where two-character capitalized identifiers are not being highlighted inside code blocks. This does not appear to be a problem in the case of two-letter identifiers where only one of the letters is capitalized. I.e. System.IO fails to highlight "IO", but System.Io would be fully highlighted. Example is C#:    I apologize if this has been inquired upon before, I didn't see it in my brief search.

I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange?


Here is an  flower in my garden. My question is based on the observation that the flower seems to be devoid of any reproductive structures, i.e., Stamen or Carpel, so how does it set seed? In the picture below it can be seen that the plant isn't sterile and successfully produces seed pods.

I found this plant in Hyderabad city of Telangana State,India.Many people of Hyderabad city have planted this flowering plant.I don't know the name of this plant.If it's flower treated as a circle,the flower has diameter of nearly 6cm length.Can any one tell me what is the name of this plant?


I'm having a hard time to figure out what is wrong with the follwoing MWE  \documentclass{article} \usepackage{amsmath} \begin{document} \begin{align*} \langle n,l',l_s',m',m_s'\vert H_{\rm SO}\vert n,l,l_s,m,m_s \rangle = \frac{1}{2m^2c^2 a_0^3n^3}\frac{\delta_{l'}^l}{l(2l+1)(l+1)} \left( & \sqrt{l(l+1)-m(m+1)}\sqrt{3/4-m_s(m_s-1)}\delta_{m'}^{m+1}\delta_{m_s'}^{m_s-1}\\ & \sqrt{l(l+1)-m(m-1)}\sqrt{3/4-m_s(m_s+1)}\delta_{m'}^{m-1}\delta_{m_s'}^{m_s+1}\\ & (m+m_s)\delta_m^{m'}\delta_{m_s}^{m_s'} \right) \end{align*} \end{document}   It says that I forgot to close a bracket, but I fail to see where...

I have a very long equation that must be separated into two lines, and it has several pairs of nesting \left \right delimiters. Unfortunately, it seems that they need to be on the same line in order for them to work.  Also I'm using the align environment because I need the aligning functionality. Is there a way to have the size of delimiters automatically adjusted over multiple lines?


I have 3 groups of raster layers all in the same place, but my group with my vector layer are located above... I am working in QGIS.  They all have the same CRS WGS 84 / EPSG Greenland Polar Stereographic, EPSG:5938.  The project, each vector layer and raster layer have the same CRS.  Why are they not on the same position and how do i get them to be that?

I have made a raster elevation map of Greenland, and have information of the region, cities and more as vectors. The information is not in the same place as my elevation map.  I have selected EPSG:5938 on the bottom right in QGIS and on my informations and elevation map I have set the CRS to the same like the picture    How do I get it all on the same position?


I was able to do only this. Please help with an explanation. This is a homework question.

$\sqrt{3}(\cot 70^\circ + 4 \cos 70^\circ ) =$ ?   The answer is $3$.   My progress so far:  \begin{align} \sqrt{3}(\cot 70^\circ+4\cos 70^\circ)&= \sqrt{3}(\tan 20^\circ+4\sin 20^\circ) \\ &= \sqrt{3}(\sin 20^\circ)\left(\frac{1}{\cos 20^\circ}+4\right)\\ &= \sqrt{3}\frac{(\sin 20^\circ)(1+4\cos 20^\circ)}{\cos 20^\circ}\\ &= \sqrt{3}\frac{(\sin 20^\circ+2\sin 40^\circ)}{\cos 20^\circ}\\ \end{align}


Let $A$ be a $n \times n$ matrix with complex elements, $L$ a $1 \times n$ matrix with complex elements and $C$ a $n \times 1$ matrix with complex elements. Show that $\det (A-CL)=\det(A)-LBC$, where $B=\textrm{adj}(A)$ is the adjugate matrix of $A$.

I would like a proof of the following result, given on .  For all square matrices $\mathbf{A}$ and column vectors $\mathbf{u}$ and $\mathbf{v}$ over some field $\mathbb{F}$, $$ \det(\mathbf{A}+\mathbf{uv}^\mathrm{T}) = \det(\mathbf{A}) + \mathbf{v}^\mathrm{T}\mathrm{adj}(\mathbf{A})\mathbf{u}, $$ where $\mathrm{adj}(\mathbf{A})$ is the adjugate matrix of $\mathbf{A}$.  Note that $\mathbf{A}$ may be singular. However, the proof given on wikipedia requires that $\mathbf{A}$ is nonsingular.


I was wondering about the following: When I wanted to know whether 0.3/3 == 0.1 in Haskell, the answer was false. Then I checked what 0.3/3 actually is in Haskell and as I found out it was 0.099999. I have absolutely no idea why this is the case. Could anybody help me with that?

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


Except for LTS Ubuntu doesn't support software updates from "cycled out" versions (like 19.04 just became and 18.10 before that)  it provides  updated in April. My issue is: It provides a guide to trick your computer into updating from 18.10 to 19.04, as 19.10 was the current version at the beginning of this year the update from 19.04 was still supported and as such the user could then update to 19.10 the easy conventional way, after the 18.10 -> 19.04 passage. My "strategy" was then to 18.10 -> 19.04 this way, do the same process but for 19.04 -> 19.10, and from 19.10 to 20.04 by updating the conventional way Just as the blog post alerts, I changed all the links for the 'disco' version in the meta-release2 file into  I also deleted all the entries for the 20.04 version in the meta-release2 file too Still - I can't do it, and it gives me the following error: Invalid package information   After updating your package information, the essential package  'ubuntu-minimal' could not be located. This may be because you have  no official mirrors listed in your software sources, or because of  excessive load on the mirror you are using. See /etc/apt/sources.list  for the current list of configured software sources.  In the case of an overloaded mirror, you may want to try the upgrade  again later.

I am currently using Ubuntu 10.04. I know there is a 10.10 release, but can I upgrade directly to 11.04? Could you walk me through the steps please?


A colleague and I are working on creating legal descriptions for several hundred districts, for which we already have shapefiles. I'm wondering if there's a way to use COGO to help provide a description of the outline of it?  I'm fairly certain it's going to use parcel fabrics, and/or a model.

Lots of questions about turning metes and bounds into a polygon, but how about going in reverse? Are there any existing tools or do I need to look at building a script myself?  Ultimately I'd like to generate points with x/y and at all the vertices and line segments with distance and direction as attributes (so I can label them).   This for submission to our local government as part of their legal requirements.


So in my program I'm using tkinter to handle my key presses  However my program runs in a tick loop and I've found out that my programs tick loop and tkinters main loop are clashing with eatch other. Is there a way to fix this? Dose tkinter have a function that dose a single loop that I could call on eatch of my ticks? If not then what would you recommend replacing tkinter with to handle key pressing?

My little brother is just getting into programming, and for his Science Fair project, he's doing a simulation of a flock of birds in the sky. He's gotten most of his code written, and it works nicely, but the birds need to move every moment.  Tkinter, however, hogs the time for its own event loop, and so his code won't run. Doing root.mainloop() runs, runs, and keeps running, and the only thing it runs is the event handlers.  Is there a way to have his code run alongside the mainloop (without multithreading, it's confusing and this should be kept simple), and if so, what is it?  Right now, he came up with an ugly hack, tying his move() function to <b1-motion>, so that as long as he holds the button down and wiggles the mouse, it works. But there's got to be a better way.


If a spellcaster wants to move 10 feet toward a monster, touch it for a spell attack, and then move back 10 feet, does the monster get an opportunity attack when the magic user moves back?  Or can the magic user only move back 5 feet without incurring an opportunity attack?  I thought about the Disengage action, but it uses one's entire action.

Let's say I'm 10ft away from an enemy. In my turn, I choose to move 5ft to get close enough to attack, I do attack, then I use my remaining movement to move out of range of the enemy. Does this still allow them an opportunity attack?


How can I install gcc6.4, g++6.4 and cmake3 on Ubuntu 14.04? I want to rewrite below lines that run on Linux to be run on Ubuntu   $ yum install gcc64-c++ libcurl-devel $ export CC=gcc64 $ export CXX=g++64 $ yum install cmake3   I tried below commands on ubuntu  $ sudo add-apt-repository ppa:ubuntu-toolchain-r/test $ sudo apt update $ sudo apt install -y g++-6 $ sudo apt install -y gcc-6 $ gcc --version $ g++ --version $ export CC=gcc6 $ export CXX=g++6 $ gcc --version $ g++ --version   But version returned is   gcc (Ubuntu 4.8.4-2ubuntu1~14.04.4) 4.8.4   and  g++ (Ubuntu 4.8.4-2ubuntu1~14.04.4) 4.8.4    Although I expect to be 6.4  And when I tried to install cmake3   $ sudo apt-get update  $ sudo apt purge cmake*  $ wget http://www.cmake.org/files/v3.5/cmake-3.5.1.tar.gz  $ tar xf cmake-3.5.1.tar.gz  $ cd cmake-3.5.1  $ ./configure  $ make  $ sudo make install  $ cmake --version   It gave me an error in ./configure  CMake 3.5.1, Copyright 2000-2016 Kitware, Inc.  ---------------------------------------------  Error when bootstrapping CMake:  Cannot find appropriate C compiler on this system.  Please specify one using environment variable CC.

I want to compile my program with the latest version of gcc.  Ubuntu 14.04 comes with gcc 4.8.2, however there's 4.9.0 available, moreover, I see that it is available as a package: . I tried to install it  sudo apt-get install gcc-4.9   but it says  Reading package lists... Done Building dependency tree        Reading state information... Done Note, selecting 'gcc-4.9-base' for regex 'gcc-4.9' gcc-4.9-base is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   Looks like it is already installed, just not as the default one? How do I utilize it to build my program?


If I have a   copying , can it transform into ?  I imagine it would not — it would be similar to the rules for tokens right, it doesn't have the face to flip to, and in this case I would assume duplicate would just be exiled forever if it tried right?

Suppose my opponent has  on the battlefield, and has not yet transformed it into a Planewalker.  I cast , making my own copy of Nicol Bolas.  What happens if I activate my cloned Nicol Bolas' ability? What would happen if the ability were phrased differently, such that it doesn't require the creature to leave the battlefield and re-enter?


I am trying to delete all those elements with a specific value. Here's my code. This code is not working. Can someone help me? TIA. Example Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6 Return: 1 --> 2 --> 3 --> 4 --> 5  public class ListNode {   int val;   ListNode next;   ListNode(int x) { val = x; } }  public class Solution { public ListNode removeElements(ListNode head, int val) {     if(head == null){         return null;     }     ListNode curr = head;     ListNode prev = null;     while(curr != null){          if(curr.val == val){             prev.next = curr.next;          }         else{             prev = curr;           }           curr = curr.next;     }     return head; } }

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?


my question is about a field in my table that save time in format like "06:00 PM"(just show time without date with AM/PM). I want to change saved time that has not AM/PM then calculate difference time betwen that time and current time in minute, then if diference is between 60 minute echo something. for example some thing like this $time =date("G:i", strtotime($Time_Field)); $time=strtotime($time); $currentTime = time(); // current time $difference = $currentTime - $time; if( $difference > 0 && $difference < 60 ) { echo " your request is begin in next 1 houre "; }  My variable output is always zero even if the time interval is more than 59 minutes i test below  and this  But I was not able to calculate the difference between the time stored in the database and the current time in minutes. Thank you for your guidance

How to calculate minute difference between two date-times in PHP?


Can you find the geometric mean of a continuous variable, in a similar why to find the mean of a continuous variable. To find the regular mean of between to points on a function you do $\frac{\int_{a}^{b} f(x) \,dx}{b-a} $ If there is 1 point that lands in $0$ it would all become all zero so it might not make any sense to take a geometric mean of a continuous variable. Mean $$\frac{\sum_{n=1}^{k} a_k}{n}$$ Geometric Mean $$(\prod_{n=1}^{k} a_k)^{\frac{1}{n}}$$

If the $(\int_a ^b f(x))/(a-b)$ is the arithmetic average of all the values of $f(x)$ between $a$ and $b$, what is the expression representing the geometric average of all these values?


Simple question, should a button be disabled if the form is not finished, i.e. still missing some input of mandatory fields?  Why/Why not?

How do you think about disabling the submit-button until the user has completed the form or the required fields?   I find similar questions here on ux.se and somebody answered that the user will think that the form is broken or not immediately realize whats going on.  I think hiding is not that good but a disabling (e.g. grayscale, opacity, ...) plus a short text in the button would improve usability because the user realise that he still has to fill out something.  Is there anybody with experience or examples besides the usual error-messages/validation after submitting?


Let $C$ be the Banach space of complex continuous functions on $[0,1]$, with the supremum norm. Let $B$ be the closed unit ball of $C$. Show that there exist continuous linear functionals $\phi$ on $C$ for which $\phi(B)$ is an open subset of the complex plane; in particular $|\phi|$ attains no maximum on $B$.  I had tried it several times but I am not able to generate such a linear  continuous functional on the given space. Any type of help will be appreciated. Thanks in advance

Let $C$ be the Banach space of all complex continuous functions on $[0,1]$ endowed with the supremum norm. Let $B$ be the closed unit ball of $C$. Does there exist a $\Lambda\in C^*$ for which $\Lambda (B)$ is open? Note that $C$ is a locally convex space and $B$ is convex, balanced and closed set, by the separation theorem of convex sets,we know there exists $\Lambda\in C^*$ such that $|\Lambda f|\leq 1$ for all $f\in B$ and $|\Lambda f|>1$ for $f\in B^c$. But how about this when we consider some concrete space above?


I'm an Australian citizen who, after graduation, wants to spend 6 months travelling, most of that in US, and return for a graduate job in Australia after that 6 months.  My plan was to use the Visa Waiver Program to enter for the first 90 days, then after that's up, either return to Australia or explore the UK for a couple of weeks, and then return to the US.    Since I do not know where I will go, either AUS or the UK, until nearer the end of the time in the US, I plan on buying a one-way ticket to the US; will that raise red flags? Will I have any issues upon return to the US, after a couple of weeks spent  in either AUS or the UK?   A good note from some of the other questions I've read is that I do not have a significant other in the US, nor any family. And I have very tangible motivations to return to Australia for my graduate job.

I went to the US for 90 days on an ESTA in August to November. Then back to my home country for 1 month and then back again mid December until mid February and now I am going back again after 10 days for another 90 days. Now I can see that some people refer to 180 day rule in a year. My stay will be 240 days in one year with short gaps between coming back. Is the 180 day rule accurate? Some people write that you can do unlimited trips to The US as long as you don't stay more than 90 days. Is that correct? My reason for going there the first time was to visit and travel with an American friend.  After my first visit (she is my girlfriend) moved with me to my home country but has ended up in a custody battle in the US so she needed to return urgently so I returned only to be with her and support her, not to be a tourist.  Then after my second visit I needed to go back to my sick Dad and to rent out my apartment since we left in a rush to go back to the US.  Now, my third visit is to continue to be with my girlfriend and support her in her difficult situation.   My question is, if I do end up in trouble should I tell them this whole story? Or should I just say I am visiting a friend for a third time because I want to see more of the country and I have some more time off before I go back to my job.  I have proof of money in my bank account and I stay and eat with her for free Documented proof that I have a job to return to in my home country My return ticket printed and an address to stay at in the US and I have proof I have an apartment in my home country


No matter what, every single Pokemon that I try to catch runs away from me! I can't spin any Pokestops, and I can't fight any gyms!  I've heard about something called a soft ban. Is that what's happening to me?

I can't do anything now. Can't catch Pokemon, can't get items. Does anyone have the same problem?


Is there anything that would allow me to run a GUI on client side of SSH(ie on windows)& that would convert the GUI actions made to corresponding commands to be sent via SSH client(in my case putty) to remote ubuntu server ? Also it could show me the corresponding commands that it sends via SSH. I dont have GUI installed on my ubuntu server so I am looking out for any tools that may be installed on the client(running windows 7) that communicates to ubuntu server via SSH.  Does anything like that exists ? Or may be a tool that helps me doing frequent actions via Putty more easily than me requiring to remember exactly how to accurately write all the ubuntu commands ?

I'm going to accessing my ubuntu machine remotely from my windows machine through putty. Are there any suggestions for possible ways to get an X server running on my windows machine?  Thanks.


Error: Implementation restriction: Implementation restriction:   ContentDocumentLink requires a filter by a single Id on   ContentDocumentId or LinkedEntityId using the equals operator or   multiple Id's using the IN operator.requires a filter by a single Id   on ContentDocumentId or LinkedEntityId using the equals operator or   multiple Id's using the IN operator.   Code:  public static List<AttachWrapper> getAttachment(Id parentId){          //attachmentList = [SELECT Id, Name, Description, CreatedDate, LastModifiedDate, ParentID FROM Attachment WHERE ParentID =:parentId];          ConDocLnk= [SELECT ContentDocumentId FROM ContentDocumentLink WHERE LinkedEntityId =: parentId ];}   I've faced error while fetching ContentDocumentLink records with setting filter as its parent id

I have to get all the "linked" records from a Document (ContentDocument) and then filter only the Events from them using the following apex.  // Query ContentDocumentLink object for the 'Event' link and apply 'WHERE' filter of the above map's contentdocument id. Map<id, Event> mapEvent = new Map<id, Event>(); Set<Id> EventIds = new Set<Id>(); for(ContentDocumentLink cdlForEvent: [SELECT ContentDocumentID, LinkedEntity.type, LinkedEntityId                                      FROM ContentDocumentLink                                      WHERE ContentDocumentID IN: mapOfContentVersion.keySet()]) {     if(cdlForEvent.LinkedEntity.Type == 'Event')     {         EventIds.add(cdlForEvent.LinkedEntityId);     } }   I'm using ContentDocumentId filter, from a contentversion map but it is giving me following error     Implementation restriction: ContentDocumentLink requires a filter by a   single Id on ContentDocumentId or LinkedEntityId using the equals   operator or multiple Id's using the IN operator.   Interestingly, if I provided hard-coded values using IN clause then it accepts it. But I have to make it run in the apex and it has to be dynamic. Following soql works   for(ContentDocumentLink cdlForEvent:                  [SELECT ContentDocumentID, LinkedEntity.type, LinkedEntityId                  FROM ContentDocumentLink                  WHERE ContentDocumentID IN ('06923000000CqHNaxy', '06923000000CqHNAA0')])   I dont understand what is missing. How should I get all the related linked entity records and then filter Events from them?


I've imported a Lego model into Blender. How do I group the parts together so I can transform them as a single unit? I don't want the individual parts to be selectable using the mouse. Thanks.  [edit]  I found the answer here:    So this is a duplicate.

I've never been quite able to figure out how groups work in Blender (at least not since 2.5/6x). Is it possible to group several objects and then manipulate them (scale, rotate, translate) as one?


I need to add some JS to some salesforce standard edit pages to allow us to add functionality to aid in data entry.  I would like to do it the "correct" way and my salesforce knowledge isn't great. I have however read all I can find and established that up to recently (last few days?) you could add a widget to the sidebar that would inject JS onto every page or edit pages etc but this seems very hacky and as I mentioned seems to have been disabled now.  The option that seems to be the best and most supported is to add a new VisualForce page and that uses the standardController for the page you want (for example "Contact") then include the default page for example:  <apex:page standardController="Contact">     <apex:detail inlineEdit="true" /> </apex:page>   and then throw in the JS to do the work or maybe some kind of include of the JS resource? like:  <apex:includeScript value="{!$Resource.example_js}"/>   Now a few quick tests using something like:  <apex:page standardController="Contact">     <apex:detail inlineEdit="true" />      <script type="text/javascript" language="Javascript">         alert('Do stuff here...');     </script> </apex:page>   Which appears to work fine for the in-line edit option but I really want to use it for both the main edit page and the new page (might be the same). This is where I have hit a brick wall as I can't find out how to build a page the "inherits" the standard edit/new page.  I don't want to be creating custom pages as this would mean that any already configured custom fields wouldn't be there and would make adding/removing fields require the VisualForce page to be updated (not the easy drag and drop of the standard page editor!)  So to conclude: I want to add custom JS to a lot (all if easier?) new/edit forms the "right" way. I don't mind creating custom VisualForce pages for each of the edit pages BUT the new pages MUST just have the same layout etc as the original pages and update when they do. :) I'm SURE that's not to much to ask? ;)  Thanks  P.S. Please assume I have no knowledge of salesforce and point me to any info required for the solution as I really only started using salesforce Monday! ;)

Reading through this doc:      We replaced the rich text editor in HTML Area home page components   with a new version that supports more markup but doesn’t allow HTML to   be manually entered.      In Summer ’15 we will start removing unsupported code from HTML Area   home page components. As a result, components that contain JavaScript,   CSS, iframes, or other unsupported markup might stop working properly.   To use JavaScript or other advanced HTML elements in your home page   component, we recommend that you use a Visualforce Area component   instead.   With Visualforce homepage component the best we could do is design fancy home page components, which has not been the big use of sidebar amongst developers. How do we do the fancy hack we do today using html components since visualforce is hosted in a different domain will the sidebar hacks even work after summer 15?     You can include JavaScript in your Visualforce page, but because the   component is rendered in an iframe on the home page layout, the   JavaScript can’t interact with the page that contains the component.   Finally why this move :(?


Are Tommen Lannister and Myrcella Lannister offspring from the (incestuous) relationship of Jaime and Cersei Lannister as well?

Joffrey came across as a bit of a little **** in Seasons 1 and 2, but in Season 3 (especially the end of The Climb) we see that he is utterly, utterly insane.  Could the source of this madness be that he is actually be born of incest between Jaime and Cersei? How could anyone know?


It would be useful to be able to have comments on a bounty once it has started so that:   The bounty poster can add updates if they want to clarify what they are looking for. (This would be less needed if it was possible to ) People can ask the bounty poster to clarify what they are looking for.   I've just posted a bounty and I'd like to add something to the message. The only option at the moment is to add comments to the question which I'm reluctant to do as the will not be relevant to the question once the bounty has been awarded.

I put up  over on SO with the assumption that the text would be formatted like it is for a question or answer.  I'm not really sure if I was incorrect in my assumption, or if I just formatted my text improperly, as I can't go back and edit what I put in.  Am I missing an obvious feature?  If not, would it be reasonable to request bounty-text edits—perhaps with moderator-approval to prevent abuse?  Edit: I was trying to use markdown to produce an unordered list as part of my bounty.  What you see in the link is a blob of text with dashes separating phrases


When writing questions and answers here about the Harry Potter series, I often need a word for "someone who's not a Muggle". People often refer to "the wizarding world" as opposed to the Muggle word, so "wizard" would be one choice - but it seems slightly sexist to exclude witches in that way. On the other hand, "witch or wizard" is a bit cumbersome, much longer than the simple word "Muggle".  Is there a sensible word to use which is neither sexist nor cumbersome, that makes a good equivalent to "Muggle"? What would JK Rowling say to fill in a sentence such as this:     Muggles use technology, while [...] use magic.

In the Harry Potter world, there's the term "muggle" for people with no magical abilities, "muggle-born" for those with magical abilities who's parents are muggles and "squib" for those with no magical abilities who's parents are magical.  But is there any collective term for all magical people (as opposed to wizards for males and witches for females)?  I don't recall seeing any word that refers to all men and women and children with magical abilities, and it's the only group left without noun or collective noun to describe them.


Let $f,g$ $C^0$ functions from $[0, 1] \to \mathbb R$, and a sequence of $C^1$ functions $f_n : [0, 1] \to \mathbb R$. Show that if $f_n'$ converges uniformly to $g$ and $f_n$ converges pointwise to $f$, then $f$ is $C^1$ and $f'=g$. I tried to write with the definitions and using mean value theorem to involve the derivative in the $\delta,\epsilon$ expressions but it does not lead me anywhere. A hint was to integrate but I struggle to show the proposition using integrals. Can someone help me ?

This is ex. 14.2.7. from Terence Tao's Analysis II book.   Let $I:=[a,b]$ be an interval and $f_n:I \rightarrow \mathbb R$ differentiable functions with $f_n'$ converges uniform to a function $g:I \rightarrow \mathbb R$. Suppose $\exists x_0 \in I: \lim \limits_{n \rightarrow \infty} f_n(x_0) = L \in \mathbb R$. Then the $f_n$ converge uniformly to a differentiable function $f:I \rightarrow \mathbb R$ with $f' = g$.  We are not given that the $f_n'$ are continuous but he gives the hint that $$ d_{\infty}(f_n',f_m') \leq \epsilon \Rightarrow |(f_n(x)-f_m(x))-(f_n(x_0)-f_m(x_0))| \leq \epsilon |x-x_0| $$ This can be shown by the mean value theorem. My question is : How does this help me to prove the theorem ?


I am currently working with ArcMap to develop an elevation model of a quarry showing how the terrain at the quarry site would look post-closure. One of the requirements is that the slopes placed along the benches should be 30 degrees exactly. I have an elevation model of the site and a shapefile showing all the quarry leases. One of the assumptions is that the boundary elevation shall remain the same in the future and all of the rock within the boundary would be extracted. The final base elevation is assumed to be 100m for the time-being; i.e. elevation of the pit surface post closure.  To start, I extracted the elevation points of the boundaries where the slopes shall be put in; using "Extract by Mask" and "Sample" to tabulate the values and then import them into a new template. I was wondering if it would be possible to create the points at the base of the slope using Excel; i.e. design some sort of an algorithm that will determine the XY coordinates of a point inside the boundary such that:   The distance between a point on the boundary and the corresponding point inside the boundary is (Boundary Elevation - 100)/tan 30deg. The point inside the boundary is such that it's on a line perpendicular to the line where the boundary point is situated.   However I'm pretty sure this would take quite a lot of time and would not be the optimal way of going about the problem. As the final base elevation is subject to change, it would be better to have a solution that doesn't require much effort.  What would be the optimal way of creating the elevation model?  I have gone through some of the forums in ESRI as well as stackexchange but haven't been able to understand the methods suggested, particularly those involving python as I don't have any experience working with Python. So I was wondering if it will be possible to work on it without using python or if it does require the use of python, could anyone explain to me how the script can be written?   The method suggested for this question for instance:

I wanted to create a DEM of constant slope say 1/3000.   How can I proceed in ArcGIS Desktop 9.3?   The area may be 1000m x 1000m or any other as per convenience.


I need the ia32-libs packages because Petalinux SDK requires it.  I have just updated to Ubuntu 15.10 today, and now it won't let me install this package. I've installed it before on Ubuntu 15.04, so there should be no reason why it won't install on 15.10, right?  I've added the correct file to the sources.list.d directory.      ┌─[♨ steven ♨ ][~]      └─(20:38)(pts/2) Prometheus ─╼ cat /etc/apt/sources.list.d/ia32-libs-raring.list deb http://old-releases.ubuntu.com/ubuntu/ raring main restricted universe multiverse   I did an update and tried to install the package, but this is all that happens...      ┌─[♨ steven ♨ ][~]      └─(20:41)(pts/2) Prometheus ─╼ sudo apt-get install ia32-libs Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  ia32-libs : Depends: ia32-libs-multiarch E: Unable to correct problems, you have held broken packages.     ┌─[♨ steven ♨ ][~]      └─:( (20:42)(pts/2) Prometheus ─╼ sudo apt-get install ia32-libs-multiarch Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  ia32-libs-multiarch:i386 : Depends: bluez-alsa:i386 but it is not going to be installed E: Unable to correct problems, you have held broken packages.   However when I try to install the bluez-alsa:i386 package, it tells me it needs bluez:i386. When I try to install that one, it tells me I need bluez-alsa:i386 ... if I try to install both, it tells me they conflict with each other...  Is something broken that I am not seeing? Is support for this ia32-lib package completely gone?   Do I just need to downgrade back to 15.04?  I am running 15.10 64-bit

I have a 64-bit version of Ubuntu 13.10.  I want to run a 32-bit version of a program.  However I see ia32-libs is not included in 13.10.  Is there a replacement package for this or what?


This is coming from Charlie and Cardi B on BBC1 radio show:     Charlie - Would you rather have a night out with me or Offset?   Cardi B - With my man (Offset)   Charlie - Come on, man! I know London better than Offset, I can show you all sick spots.   What does “sick spots” mean?

"That's a sick set of wheels!"   I've heard it from someone and I'm wondering what the exact meaning is.  I googled the phrase and all I found was a .  I know that one of the meanings of  as an adjective is:     very good, excellent   I also found  for "set of wheels":     a car   So does "That's a sick set of wheels!" mean "That's a very excellent car"?


I have the following file:  export TMOUT  PS1="$(hostname):${LOGNAME}:\${PWD} ${PROMPT} " PS1="${FGOLD}$(hostname):${LOGNAME}:\${PWD} ${PROMPT} ${NORMAL}"   PS1=abd   PS1="$(hostname):$LOGNAME:\$PWD $PROMPT "   export PS1 LANG   I need to add the line below under the line matching export TMOUT:  FGOLD=`echo "\033[1;32m"`       So, the final output should look like this:  export TMOUT   FGOLD=`echo "\033[1;32m"`      PS1="$(hostname):${LOGNAME}:\${PWD} ${PROMPT} " PS1="${FGOLD}$(hostname):${LOGNAME}:\${PWD} ${PROMPT} ${NORMAL}"   PS1=abd   PS1="$(hostname):$LOGNAME:\$PWD $PROMPT "   export PS1 LANG   The command below is not working:  sed 's/.*export.*\TMOUT./&\FGOLD=`echo "\033[1;32m"`/' pro   outputs:  export TMOUT    PS1="$(hostname):${LOGNAME}:\${PWD} ${PROMPT} " PS1="${FGOLD}$(hostname):${LOGNAME}:\${PWD} ${PROMPT} ${NORMAL}" PS1=abd PS1="$(hostname):$LOGNAME:\$PWD $PROMPT " export PS1 LANG

So I've been using 'sed' on linux for a while, but have had a bit of difficulty trying to use it on OSX since 'POSIX sed' and 'GNU sed' have so many little differences.  Currently I'm struggling with how to insert a line of text after a certain line number. (in this case, line 4)  On linux I would do something like this:  sed --in-place "4 a\  mode '0755'" file.txt   So on OSX I tried this:  sed -i "" "4 a\ mode '0755'" file.txt   However this keeps giving me a 'extra characters after \ at the end of a command' error.  Any ideas what's wrong here?  Do I have a typo?  Or am I not understanding another difference between versions of sed?


Let $f: \mathbb R \rightarrow \mathbb R$ defined by $$f(x) := \begin{cases}x^2 \sin \frac 1 x\ & x \neq 0\\ 0\  & x = 0\end{cases}$$  Show $f$ is differentiable on $\mathbb R$:  Let $\epsilon > 0$.  $x_0 \neq 0$: $\left\lvert\frac {x^2 \sin \frac 1 x - x_0^2 \sin \frac 1 {x_0}}{x-x_0} \right\rvert \le \epsilon$   I'm thinking that since the fraction is continuous there exists $\delta > 0$ satisfying the above for $x \in [-\delta,\delta] / \{0\}$ ?  $x_0 = 0$: $\left\rvert\frac {x^2 \sin \frac 1 x - 0} {x} \right\rvert \le \epsilon$   How can I evaluate this limit ? I cannot say the fraction is continuous at $0$ ?  Also I must find the derivative of $f$ and show it is not continuous at $x=0$, but I'm stuck.

Let $f(x) = x^2 \sin{\frac{1}{x}}$ for $x\neq 0$ and $f(0) =0$. (a) Use the basic properties of the derivative, and the Chain Rule to show that $f$ is differentiable at each $a\neq 0$ and calculate $f'(a)$. You may use without proof that $\sin$ is differentiable and that $\sin' =\cos$.  Not even sure what this is asking.  (b) Show that $f$ is differentiable at $0$ and that $f'(0) =0$.  $\frac {f(x)-f(0)}{x-0} \to \lim_{x \to 0} x \sin(1/x)$. $x \sin(1/x) \leq |x|$ and $\lim_{x \to 0} |x|=0$. Thus $f(x)$ is differentiable at $0$; moreover $f^{'}(0)=0$.  (c) Show that $f'$ is not continuous at $0$.  $f{'}(x)=x^{2} \cos(1/x) (-x^{-2}) + 2x \sin (1/x)$. In pieces: $\lim_{x \to 0} \cos (1/x)$. $f^{'}(0-)$ nor $f{'}(0+)$ exists as $x \to 0$ $f^{'}(x)$ oscillates infinity between $-1$ and $1$ with ever increase frequency as $x \rightarrow 0$ for any $p>0$ $[-p,0]$, $[-p,p]$ or $[0,p]$ $f$ is not continuous. Question: How to show more rigorously?


I want to know my video memory size and i tried method with   lshw -c display   But it shows    *-display                   description: VGA compatible controller    product: Cedar [Radeon HD 5000/6000/7350/8350 Series]    vendor: Advanced Micro Devices, Inc. [AMD/ATI]    physical id: 0    bus info: pci@0000:01:00.0    version: 00    width: 64 bits    clock: 33MHz    capabilities: pm pciexpress msi vga_controller bus_master cap_list rom    configuration: driver=fglrx_pci latency=0    resources: irq:29 memory:c0000000-cfffffff memory:d1000000-d101ffff ioport:a000(size=256) memory:d0000000-d001ffff   I tried method with sysinfo but program doesn't show my graphics card, with hardinfo same problem  My graphics card AMD Radeon HD 5450

In my Windows 8, video card shows 640 MB of available memory (Screen Resolution > Advanced Settings or with dxdiag). But ubuntu (with lspci command) shows 256 MB. so who's right?


can anybody explain me the difference in usage of these three?  For example, is it correct to ask: How many cars did you buy last two days or How many cars did you buy in the last two days?   is there a difference in meaning if I say: How many cars did you buy in the last two days vs. How many cars have you bought in the last two days?   Does present perfect include today ? For example if I say:  How many cars have you bought in the last two days? The person will tell me how many cars he bought today and yesterday? Or he would tell me how many cars he bought yesterday and the day before yesterday?  If doctor asks me how have you been feeling in the last 2 days/for the last 2 days. He means today + yesterday or yesterday + the day before yesterday?  In my country we also have this kind of grammar.  For example we can say here something like. Last two days I am worrying too much. By which we mean that I was worrying yesterday and I am worrying today too. Can I use it the same way in English?  Thanks, if there is any resource about this grammar rules online, I would like to have a look thanks!

I have this question that my brain cannot understand because for me it seems to be very illogical. Please, try to explain this to me. It is both english problem but also my native language problem.  For example: If I bought something two days ago. (e.g. Monday, so today is Wednesday) I can't say during Wednesday that I haven't bought anything for 2 days.  Because I skiped just one day and I can still buy something today no? So I would say which makes more logic to me: I haven't bought anything for 1 day.  Same as if I was at the club on Monday now is Wednesday, I would say I haven't been to that club for 1 day. Since today I can still go there. However, i saw more people using it the other way. Which in my opinion is illogical.  They say: I haven't bought anything for 2 days OR I haven't been to that club for 2 days meaning the last time they were there was two days ago. However how logical is it? Imagine you come to that club on Wednesday if you were there on Monday and say to the same barman you saw there on Monday that you haven't been here for 2 days and he would look like: what? are you stupid? You weren't here just one day.  Like as the first question, I haven't purchased anything for 2 days is valid only if you last purchased something on monday and today is thursday, in my opinion, because we should not count monday since you already bought something.  Does anybody get my point? Thanks for answers and your help.


Problem  Proof with induction that $n^2+n$ is even when $n \in \mathbb{N}$  Attempt to solve  $n^2+n$ is even when it satisfies: $$ n^2+n \mod 2 = 0 $$ meaning it's divisible by 2. I can begin to proof that this statement holds when $n \in \mathbb{N}$.  Base case  the statement holds when $n=0$  $$ 0^2+0 \mod 2 = 0 $$  Which is true since $0$ divided any $n\in \mathbb{N}$ is $0$.  Inductive step  Assume statement holds when $n=k$ (induction hypothesis)  $$ k^2+ k \mod 2 = 0 $$  then let $n = k+1$  $$ (k+1)^2 + (k+1) \mod 2 = 0 $$ $$ \iff k^2+2k+1+k+1 \mod 2 = 0 $$ $$ \iff k^2+k + 2k + 2 \mod 2 = 0 $$  Based on induction hypothesis $k^2+k \mod 2 = 0$. Which implies we can deduce our statement to  $$ \implies 2k + 2 \mod 2 = 0 $$ Which is true for $\forall k \in \mathbb{N}$ since any $k\in \mathbb{N}$ multiplied by 2 is divisible by 2. Adding 2 to this does not alter the divisibility since 2 is also divisible by 2.   Q.E.D    Is my proof correct?

I'm not entirely sure if I'm going about proving $n^2+n$ is even for all the natural numbers correctly.  $P(n): = n^2+n$     $P(1) = 1^2+1 = 2 = 0$ (mod $2$), true for $P(1)$   Inductive step for $P(n+1)$:     $\begin{align}P(n+1) &=& (n+1)^2+(n+1)\\ &=&n^2+2n+1+n+1\\ &=&n^2+n+2(n+1)\end{align}$   Does this prove $n^2+n$ is even as it's divisible by $2$? Thanks!


I know, there is already an answer to this smtp-status, but sorry: i don't get it. A Customer of mine sends a big amount of mails and some can't be send cause of:  This is the mail system at host mailserver.blabla.local.  I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.  For further assistance, please send mail to postmaster.  If you do so, please include this problem report. You can delete your own text from the attached returned message.                     The mail system  <mail@domain.de>: host mail.hostingserver.de[ip] said: 354 End data     with <CR><LF>.<CR><LF> (in reply to end of DATA command)   More information:  Final-Recipient: acc1; mail@domain.de Original-Recipient: acc1;info@domain.de Action: failed Status: 5.5.0 Remote-MTA: dns; mail.hostingserver.de Diagnostic-Code: smtp; 354 End data with <CR><LF>.<CR><LF>  Return-Path: <sender@domain.de> Received: from localhost (localhost [127.0.0.1])     by neptun.migra-mv.local (Postfix) with ESMTP id 071A07418E6;     Thu,  3 Nov 2016 12:04:22 +0100 (CET) X-Virus-Scanned: by amavisd-new-2.10.1 (20141025) (Debian) at migra-mv.local Received: from mailserver.blabla.local ([127.0.0.1])     by localhost (mailserver.blabla.local [127.0.0.1]) (amavisd-new, port 10024)     with ESMTP id ZkXsQejEkDHg; Thu,  3 Nov 2016 12:04:10 +0100 (CET) Received: from [192.168.2.196] (unknown [192.168.2.1])     by mailserver.blabla.local (Postfix) with ESMTPSA id 512A8741B70;     Thu,  3 Nov 2016 12:03:31 +0100 (CET) To: Migra MV <sender@domain.de> From: IntegrationsFachDienst Migration MM <sender@domain.de> Subject: =?UTF-8?Q?Aktuell:_=c3=9cber_200_Bildungsma=c3=9fnahmen_auch_f?=  =?UTF-8?Q?=c3=bcr_Zugewanderte_in_ganz_M-V?= Message-ID: <045abb9f-de00-bdc5-cede-01e338164930@migra-mv.local> Date: Thu, 3 Nov 2016 12:03:51 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101  Thunderbird/45.2.0 MIME-Version: 1.0 Content-Type: multipart/mixed;  boundary="------------55D5725BF82BAD7B1782022E"   Why are we getting this error and aren't the messages sent? In fact, most of the messages are send without problems. Could this be an error from the recipient?

On webmail every user gets error "ERROR: Message not sent. Server replied: 354" while sending mails.   But mails are sent properly and reaches properly.  Can you tell me where is problem, and why it is occurred?  UPDATE: I found in some resources that this is not an error but standard information message. On the other side, it's annoying. Can you tell me if it is a true, and if it is how can I avoid it?


From what I understand, the stock price is based on supply and demand. For example, if a stock that was priced at $0.01 was bought buy an investor who spent $5.00 (leaving him with 100 shares), it would drive the price of the stock up.  But I am wondering, who (or what) determines how much the price of the stock will go up, or down?  How do prices change? Is it a program that updates the price of every stock, every second, based on some formula? Or is it some speculating "geek" that hides in some wall street office, updating the prices on every stock he sees based on the market volume?  Thank you for any help. All help is greatly appreciated.

Is stock price determined only by the last trade that takes place?  For example, if a stock I own is trading at $3.42, and I place a Sell Limit order for $0.00, will the stock price temporarily dip to $0.00?  Likewise, if I place a Buy Limit order for $100.00 for a stock that is trading at $1.23, will the price spike to $100.00?  Is there some sort of "average price" that is reported on the stock ticker?  Thanks for your help in understanding this!


I have a problem creating an animated film as a university project. We work as a group. One of us created a landscape and the others animated a panda. I appended the landscape to the panda file and the others the panda into the landscape file. All my files have shadows on the ground from trees and the panda. The other files just have a shimmering shadow. I've been googling a lot but I can't find any solution. This happens only with Eevee, with Cycles all shadows are shown. I'll upload two files, one from me and one from a fellow student. Maybe someone can help me :)   Best wishes Nathalie

As shown in the gif, the shadow in eevee is clipped by the camera distance. The same is true for F12 rendering. Where are the options to improve this issue?


Ubuntu 14.04 live cd asks for password and login upon trying to install or try the live environment. What should I do ?

When I boot Ubuntu 10.04.3 from a live CD, it asks me to enter a username and password. I have not booted before, and I haven't created an account.


It's clear from the 1992 start date of the Eugenics Wars that Star Trek's timeline has already diverged from ours. Are there any earlier points of divergence? In DS9's "Little Green Men" episode, Quark and company traveled back to Roswell in 1947, but that caused no apparent changes.  I can't think of any earlier events, but I'm not an expert.

Note that my question assumes as a given that Star Trek is in an alternate universe which diverged from ours at some point in history.  That seems really, really obvious and undeniable to me.  So the question then becomes: at what point in time did the two universes diverge and have different histories?


What is the difference between:     they were married   they got married   they married?   Would you, considering what you say about these terms, tell me how to use these terms?

To make things simpler I assume that getting and being in the following sentences have the same meaning. So I will use being as less colloquial.  I am being (getting) married. (passive)  This sentence is in the passive form. What would be the active form? I suppose:  Something is marrying me. (active)  Sounds to me like the object is in the middle of an action. The bride and groom stand before a priest who is reading the common lines. And the bride thinks: "I am being married." But people say it long before the wedding:  I am being married in July. (Active ~ The church is marrying me in July.) Congratulate me, I'm being married. (But he / she is not in the middle of a marriage.)  Wouldn't it be more accurate to say "I will be married in July." or "Congratulate me, I am going to be married." Because the marriage is a kind of a contract (a one shot deal.)


Could someone give me an example where $X_{n}$ and $Y_{n}$ converge in $L^{1}$ but $X_{n}Y_{n}$ doesn't converge in $L^{1}$?

If $f_n$ converges to $f$ in $L^1$ and $g_n$ converges to $g$ in $L^1$. Does it necessarily mean that $f_ng_n$ converges to $fg$ in $L^1$ for finite measure spaces.


Once we get down to the quantum level, mass is derived directly from energy.    From : Most of the mass of hadrons is actually QCD binding energy, through mass-energy equivalence. This phenomenon is related to chiral symmetry breaking. In the case of nucleons – protons and neutrons – QCD binding energy forms about 99% of the nucleon's mass. That is if assuming that the kinetic energy of the hadron's constituents, moving at near the speed of light, which contributes greatly to the hadron mass, is part of QCD binding energy. Considering that nearly all of the atom's mass is concentrated in the nucleons, this means that about 99% of the mass of everyday matter (baryonic matter) is, in fact, chromodynamic binding energy.   Since we know that velocity is a main cause of time dilation, would it not be true that it is the velocity of the hadrons constituents, moving at near c, that is the true source of time dilation for any object, including a planet or star?

Is gravitational time dilation caused by gravity, or is it an effect of the inertial force caused by gravity?    Is gravitational time dilation fundamentally different from time dilation due to acceleration, are they the same but examples of different configurations?    Could you recreate the same kind of time dilation without gravity using centrifugal force?


Source: International Mathematical Olympiads, 2019.   The question is:      Let $\mathbb{Z}$ be the set of integers. Find all functions  $f: \mathbb Z \to \mathbb Z$ such that, for all integers $a$ and $b$, the following is true    $$f(2a) + 2\,f(b) = f\big(f (a+b)\big)\,.$$   I only managed to do this:   Suppose some function f has the form : f(x)= n.x ( with n, integer).   We would get :   n(2a)+ 2(nb) = n(n(a+b))  --> 2na + 2nb = n²(a+b)   --> 2n (a+b)  = n²(a+b)    ( Dividing by a + b, provided a+b is not equal to 0)   --> 2 n = n²   --> n² = 2 n   --> n = 2.    ( Although I wonder whether dividing by number n is legal, even if n is not 0)   So, apparently, if a function satisfying the f-conditions has form f(x)= n.x, then   this function must have form f(x) = 2x.   However, apparently, f must have any sum ( a + b) in its domain, in order to be from Z to Z; for the expression f( a+b) featured in the expression defining f.  But, while solving the equation, I excluded the case in which (a+b)= O. Notwithsatnding (0 + 0) is a sum of integers.   So, my hypothesis fails, and I am left with a negative conclusion :   there is no function f ( satisfying the f formula)  such that f(x) = n.x.

This was Problem 1 from the 2019 International Mathematics Olympiad.  Find all functions $f$ : $\mathbb{Z}$ $\rightarrow$ $\mathbb{Z}$  that satisfy $f(2x) + 2f(y) = f(f(x+y))$ whenever $x , y$ $\in$ $\mathbb{Z}$.  And this is my progress...  Let $x=y$ then $f(2x) + 2f(y) = f(f(x+y))$ then $f(2x) + 2f(x) = f(f(2x))$ (substitute $x$ with $y$) then $2f(x) + 2f(x) = f(2f(x))$ (from Cauchy's theory $f(nx) = nf(x)$ where $n > 0$) then $4f(x) = 2f(f(x))$ (from Cauchy's theory $f(nx) =nf(x)$ where $n > 0$) then $2f(x) = f(f(x))$ (divide both sides by $2$) then $f(x) = 2x$ which is one of the satisfied fuctions. Let $x = -y$ then $f(2x) + 2f(y) = f(f(x+y))$ then $f(-2y) + 2f(y) = f(f(-y+y))$ (substitute $x$ with $-y$) then $2f(-y) + 2f(y) = f(f(-y+y))$ (from Cauchy's theory $f(nx)=nf(x)$ where $n>0$ ) then $2f(-y) + 2f(y) = f(f(0))$ (from additional inverse property of any integers) then $2f(-y) + 2f(y) = 0$ (from Cauchy's theory $f(0)=0$ ) then $f(-y) = -f(y)$ (from additional inverse property of any integers, since $f(y)$ $\in$ $\mathbb{Z}$) then all functions $f$ : $\mathbb{Z}$ $\rightarrow$ $\mathbb{Z}$ that satisfy $f(2x) + 2f(y) = f(f(x+y))$ whereas $x,y$ $\in$ $\mathbb{Z}$ are odd.  I can't continue because I'd almost lost my dinner when I solve this, so I decided to take some Clorazepate and sleep. Can you continue or check my progress? Is it right or not? Can you help me please?


Is there a way to geomtrically visualize the identity (1³ + 2³ + ... + n³) = (1 + 2 + ... + n)², n ∈ ℕ? Are there any other similar identities?

$$(1+2+\cdots+n)^2=1^3+2^3+\cdots+n^3$$  I noticed this only because $\displaystyle \sum_{i=1}^n i = \frac{n(n+1)}{2}$ and $\displaystyle \sum_{i=1}^n i^3 = \frac{n^2(n+1)^2}{4}$.  But the two things look completely different and I can't think of an intuitive reason I would have seen this connection. Something like the 'Proof Without Words' images. Or a trick I could use while expanding the right hand side to transform it to the sum of cubes.


I moved my existing MS SQL database to PostgreSQL containing 160000 records, now I am having issue setting my Primary Keys auto increment. I have created sequence but it starts from 1 that create duplicate value, I want to start PK value from max value existing already in table for example if existing PK value is 8568 i want to start my sequence from 8568 and same for all the other tables in database.

I ran into the problem that my primary key sequence is not in sync with my table rows.   That is, when I insert a new row I get a duplicate key error because the sequence implied in the serial datatype returns a number that already exists.  It seems to be caused by import/restores not maintaining the sequence properly.


I'm using the package , setting the language to nynorsk. I notice, however, that polyglossia's feature for the abstract environment is incorrect, since Sammendrag is not Nynorsk. How can I override this and provide my own heading in this case?  \documentclass{article} \usepackage{polyglossia}     \setdefaultlanguage{nynorsk}  \begin{document} \begin{abstract} \end{abstract} \end{document}

I'd like to modify the names used to typeset some of my document elements. For example, the caption of figure floats should change from "Figure" to "Fig.", and my \tableofcontents sectioning heading shouldn't read "Contents", but "Table of Contents". How can I do that?  \documentclass{article} % \usepackage[english]{babel} \begin{document} \tableofcontents \section{foo} \begin{figure}[h] \centering \rule{1cm}{1cm}% placeholder for graphic \caption{A figure} \end{figure} \end{document}


I am using Ubuntu 16.04. the Ubuntu Software does not work.  I used a command   sudo apt install software-center   It updated my Ubuntu Software Center but still it does not work.I cannot open it.

After installing Ubuntu 16.04, the Gnome Software Center was working.  I then started to have issues with it freezing.  I decided to uninstall it through the terminal, and then reinstall it through the terminal.  If I try to open the software through Unity, the icon opens, but after a time disappears.  If I type in gnome-software in the terminal, the command just hangs until I kill it.  I've tried uninstalling and reinstalling using various commands I've found on this forum and others, but nothing will successfully reinstall the software.  All other software seems to be working fine.  Can anyone help?  Thank you.


can someone tell me why the below is not producing the correct results? It is giving me 1233 when I expected 0123.       public static readonly object locker = new object();     public static List<int> queue = new List<int>();      public static void calculate(int input)     {         Thread.Sleep(1000);         lock (locker)         {             queue.Add(input);         }     }      [TestMethod]     public void TestT()     {         int[] _intList = new int[] { 0, 1, 2, 3 };         List<Thread> _threadList = new List<Thread>();         foreach (int num in _intList)         {             Thread t = new Thread(() => calculate(num));             t.Start();             _threadList.Add(t);         }          foreach (Thread t in _threadList) { t.Join(); }          foreach (var t in queue)         {             Console.WriteLine(t);         }     }   When I change it to use a copy of the _intList variable instead, I get the correct results of 0123. Can someone tell me why this is happening? Is it being cached somewhere?          foreach (int num in _intList)         {             int testNum = num;             Thread t = new Thread(() => calculate(testNum));             t.Start();             _threadList.Add(t);         }

In the two following snippets, is the first one safe or must you do the second one?  By safe I mean is each thread guaranteed to call the method on the Foo from the same loop iteration in which the thread was created?  Or must you copy the reference to a new variable "local" to each iteration of the loop?  var threads = new List<Thread>(); foreach (Foo f in ListOfFoo) {           Thread thread = new Thread(() => f.DoSomething());     threads.Add(thread);     thread.Start(); }   -  var threads = new List<Thread>(); foreach (Foo f in ListOfFoo) {           Foo f2 = f;     Thread thread = new Thread(() => f2.DoSomething());     threads.Add(thread);     thread.Start(); }   Update: As pointed out in Jon Skeet's answer, this doesn't have anything specifically to do with threading.


Some of the referenced cells are blank and I would like that to be carried over instead of returning "0" in the cell This is my formula - =VLOOKUP(B2, SKUs!A$2:$E$7, 3, FALSE) Thanks for any assistance!

I have an Excel 2010 workbook that contains a number of individual worksheets. The cells on one of the sheets are linked to individual cells on two other worksheets in the same workbook.  I'm using a direct cell reference that essentially says that whatever value is entered into a particular cell on one sheet also populates cells on two other sheets.  I used the (=) function with the cell reference to accomplish this.  The issue I'm running into is that, even when the primary cell is left blank, the cells that populate from that primary cell will display 0, rather than remaining blank themselves.  I want the subordinate cells to remain blank if the primary cell they're linked to is blank.


When I read research papers, I saw that many people do a normality test first, then decide if a t-test or a non-parametric test should be applied.  I have a concern about such practice. Let’s say the sample follows a gamma distribution, which is kind of bell shaped, but different from normal. The larger the sample size, the more power the normality test has. So a big sample size can lead to the rejection of normality. On the other hand, the larger the sample size, the better fit with central limit theorem. As a result, even though the sample is not normal, its mean can be approximated by normal.   So we have a paradox: on one hand, large sample means its mean can be approximated by normal, which means t-test can be applied.   on the other hand, large sample give normality test more power, which in turn rejects the use of t test.   Is my concern valid? Why people do normality test? Is there an alternative way?

A former colleague once argued to me as follows:      We usually apply normality tests to the results of processes that,   under the null, generate random variables that are only   asymptotically or nearly normal (with the 'asymptotically' part dependent on some quantity which we cannot make large); In the era of   cheap memory, big data, and fast processors, normality tests should   always reject the null of normal distribution for large (though not insanely large) samples. And so, perversely, normality tests should   only be used for small samples, when they presumably have lower power   and less control over type I rate.   Is this a valid argument? Is this a well-known argument? Are there well known tests for a 'fuzzier' null hypothesis than normality?


Is it true that $\sqrt{n!}\notin\mathbb{Z}$ for $n>1$? This is what I did: By induction: for $n=2$ its trivial ($\sqrt{2}$ is irrational). Suppose its true for some $n\in\mathbb{N}$, then the primefactorization has to be $n=p_1^{a_1}\cdots p_m^{a_m}$ for some $m\in \mathbb{N}$ where there has to be a $a_i$ such that $2\nmid a_i $ and $1\leq i\leq m$. If $n+1$ is prime, then we are done. suppose its not prime, then $n+1=q_1^{b_1}\cdots q_l^{b_l}$ for some $l\in \mathbb{N}$. From here on I got stuck. First: is the statement actually true (give counterexample)? If its true, can you give me hints? Thanks.

Can $n!$ be a perfect square when $n$ is an integer greater than $1$?  Clearly, when $n$ is prime, $n!$ is not a perfect square because the exponent of $n$ in $n!$ is $1$.  The same goes when $n-1$ is prime, by considering the exponent of $n-1$. What is the answer for a general value of $n$?  (And is it possible, to prove without Bertrand's postulate. Because Bertrands postulate is quite a strong result.)


I have had this question for some time now.  For example: I currently have only 1 rep point.  If I ask a question and receive a lot of downvotes, this will not currently affect my reputation (since my rep is only 1 point).  But then, in the future, if I get more reputation points, then will the downvoted question affect my current reputation?

On Stack Exchange, users may gain a certain level of reputation.  What does reputation do? How can a user gain or lose reputation?   See also   in the Help Center  - Maximum amount of votes a user can use in a day and reputation requirements to vote.  - How to get an exact overview of the actions that got you your reputation.  - A full list of all privileges granted at each reputation level on all sites.


Can anyone tells me why does't the second snippet  catchs the 'groups' when use g flag ?         "123".match(/(\d{1})(\d{1})/)    // returns  ["12", "1", "2"]   "123".match(/(\d{1})(\d{1})/g)   // returns ["12"]   (where's 1 and 2 ?)     console.log("123".match(/(\d{1})(\d{1})/))    // returns  ["12", "1", "2"]  console.log("123".match(/(\d{1})(\d{1})/g))   // returns ["12"]   (where's 1 and 2 ?)

I want to match a portion of a string using a  and then access that parenthesized substring:  var myString = "something format_abc"; // I want "abc"  var arr = /(?:^|\s)format_(.*?)(?:\s|$)/.exec(myString);  console.log(arr);     // Prints: [" format_abc", "abc"] .. so far so good. console.log(arr[1]);  // Prints: undefined  (???) console.log(arr[0]);  // Prints: format_undefined (!!!)   What am I doing wrong?    I've discovered that there was nothing wrong with the regular expression code above: the actual string which I was testing against was this:  "date format_%A"   Reporting that "%A" is undefined seems a very strange behaviour, but it is not directly related to this question, so I've opened a new one, .    The issue was that console.log takes its parameters like a printf statement, and since the string I was logging ("%A") had a special value, it was trying to find the value of the next parameter.


Evaluate $\int_0^{\frac{\pi}{2}} \frac{\sin^3(x)}{\cos^3(x)+\sin^3(x)} dx$   $$\int_0^{\frac{\pi}{2}} \frac{\sin^3(x)}{\cos^3(x)+\sin^3(x)} dx=\int_0^{\frac{\pi}{2}} 1-\frac{\cos^3(x)}{\cos^3(x)+\sin^3(x)} dx=\int_0^{\frac{\pi}{2}} 1-\frac{1}{1+\tan^3(x)} dx$$  Then to evaluate $\int \frac{1}{1+\tan^3(x)}dx$, I let $\tan(x)=t$ and hence $dt = \sec^2(x) dx$, which implies $dx=\frac{1}{\sec^2(x)}dt$.  Then I don't know how to continue.

Calculate the following integral by hands: $$\int_{0}^{\frac{\pi}{2}}\frac{\sin^{3}(t)}{\sin^{3}(t)+\cos^{3}(t)}dt$$  It seems apparently that integration by part does not work. I think integration by substitution could work but I can not figure out how to substitute.  I have calculated it by Wolfram and the result is $\frac{\pi}{4}$.


To prove the convergence of $\sum\limits_{n = 1}^\infty\frac {n!} {n^n}$ I used that $\lim\limits_{n\to\infty}|\frac {a_{n+1}} {a_n}|$ has to be $<1$:  $$\lim\limits_{n\to\infty}|\frac {a_{n+1}} {a_n}|$$  $$=\lim\limits_{n\to\infty}|\frac {\frac {(n+1)!} {(n+1)^{n+1}}} {\frac {n!} {n^n}}|$$  $$=\lim\limits_{n\to\infty}|\frac {(n+1)!\cdot n^n} {n!\cdot (n+1)^{n+1}}|$$  $$=\lim\limits_{n\to\infty}|\frac {(n+1)\cdot n^n} {(n+1)^{n+1}}|$$  $$=\lim\limits_{n\to\infty}|\frac {n^n} {(n+1)^n}|$$  $$=\lim\limits_{n\to\infty}|{(\frac {n} {n+1})}^n|=\frac 1 e$$  Okay... problem solved after thankful advice

so I used the root test, but i'm not quite sure if i'm allowed to. I think im performing the operations correctly,a and i keep ending up with $(1)^{\infty}$. So really my question is am i performing the operations wrong or do i have to use a different test?


In what order does WordPress resources (e.g. templates, php files, media, plugins, widgets, enqueued scripts, and CSS) get loaded?  I am new to WordPress and there is some basic info I have been unable to find on this forum; I was wondering if someone might be able to describe the order in which various resources like templates, PHP files, media,  plugins, widgets, enqueued scripts, and CSS are loaded in WordPress.   asks about plugins only, but it would be helpful to know about how a page is loaded, from start to finish, so learners can get an idea about the entire rendering process.    asks users to provide a flow chart about the load order. I am requesting three things that are different;   I would like to have plugins and widgets explictly addressed. I would also like people to answer the question, and answer it using words and/or images, I am not specifically asking for a flow chart. I am also asking that respondents make an effort to avoid going into too much detail, so beginners can get a good sense of the most important parts of the loading process.     Any information is helpful, including reference links, however, those comprehensive guides are already online. The problem is that for new users, they are dense, long, and not easy to understand. I'm hoping a community member can provide an answer that gives a nice, well-rounded overview of the process, without listing every single detail that one can look up in the online guides.

So like WP must load series of files from,   index.php -> ... -> wp-header.php -> ... ->functions.php   ...and so on upon execution.   Also there must be a similar flowchart for functions callings, conditionals and such during the execution. Is such a flowchart(s) available anywhere?


I need to add some functionality to be able to print whatever is displayed in datagridview. I tried to use bitmap class but it does not seem to be printing all the rows and columns. It looks like a screenshot and missing some columns and rows. Anybody knows any better way to handle this? Thanks so much.

I am fairly new to .NET and C#, but I have a DataGridView that I would like to print.  What would be the best way to go about doing so?


It would be great if someone can let me know how do  make a slideshow background on  desktop?

How do  I create a desktop wallpaper slideshow with my own set of images?   With the images coming from a pictures folder, or pre-selected With the images displayed in order, or randomly With the images changing every few minutes, or after random periods of time


In the official Ubuntu website I can found:   the  the    But no list of tablets!  In Ubuntu web site, I can found that there is the  for installing Ubuntu-Touch. A good start, but a real list would be better, for example searching for anwsers in AskUbuntu I see  some tablet (Windows ones) can simply not run with Ubuntu "due to secure keys in order to boot up it", so I conclude that Hardware requirement is not enough.    I found a  opened 1 year ago. But the answers to this old question were about installing Ubuntu Desktop. Is there anything new with ?

With the announcement of the Ubuntu Phone OS I'd like to know what phone (and tablet) models are supported at this time.  Note from foss & Oli: We are making this the master question for all future "Will this work on <insert random tablet/phone/device here>?!" questions


My_json : {   "Monday": {     "BusinessOpenHour": "0800",     "BusinessClosedHour": "1500"   },   "Tuesday": {     "BusinessOpenHour": "0800",     "BusinessClosedHour": "1500"   },   "Wednesday": {     "BusinessOpenHour": "0800",     "BusinessClosedHour": "1500"   },   "Thursday": {     "BusinessOpenHour": "0800",     "BusinessClosedHour": "1500"   },   "Friday": {     "BusinessOpenHour": "0800",     "BusinessClosedHour": "1500"   } }  I am not able to catch the Day in the key due to which IF statement is not working: try {     Gson gson = new Gson();     Reader reader =   Files.newBufferedReader(Paths.get(filepath.getValue()));                 Map<?, ?> map = gson.fromJson(reader, Map.class);     for (Map.Entry<?, ?> entry :   map.entrySet())     {                         log(entry.getKey() + "=" + entry.getValue());         final DayOfWeek dayOfWeek = LocalDateTime.now().getDayOfWeek();                         if ((entry.getKey().toString().toLowerCase() == dayOfWeek.getDisplayName(TextStyle.FULL, Locale.US).toLowerCase() ))         {             log(map.entrySet().toString());         }     }     reader.close(); } catch (Exception ex) {     ex.printStackTrace(); }

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 would like to duplicate a mesh object, but on a particular object. Right now this is working:  import bpy   for i in range (0,5):     bpy.ops.object.duplicate(linked=0,mode='TRANSLATION')      bpy.data.objects['cube.001'].animation_data_clear()   The way I want it to do it though is that the script should only duplicate a particular object in the scene that I enter through as a string name. ATM its just duplicating the 1st object and duplicating the duplicates of the duplicates.

I've created a mesh I want to duplicate using python with specifications for the new duplicate's coordinates. How do I do that?


Question:  How to install gnome extension "workspace matrix" on Ubuntu 18.04 LTS?  Problem:  Unable to install "workspace matrix"  (or "workspace grid") on Ubuntu 18.04.  No packages appear in Ubuntu Software app when I search on "workspace matrix"  Background:  Recently managed to get my laptop dualbooted again with Ubuntu.  I successfully re-enabled grub2 on my UEFI GPT configured laptop (a Dell m5510) using an NVMe SSD.  After a couple days of running the older 16.04 LTS, I decided to update to 18.04 LTS.  So far, so good.  Welcome back to gnome, goodbye Unity (whatever).  Discovered Gnome 3's "dynamic workspace" feature, but wanted 2x2 static.  Switched to static, discovered columnar only order.  Searched Google... discovered "workspace grid" (deprecated), recommended solution "workspace matrix".  Following several web pages, they all simply said "install "workspace matrix" via Ubuntu Software app.  No such luck.  "aptitude install" and "aptitude search" not revealing.  Do I need to add a repository to be able to add "workspace matrix" on 18.04 LTS?  IF SO, which one?  I'd prefer a recommended and/or stable PPA, to avoid playing musical repositories in the future, if possible.  TIA.

How do I install GNOME Shell extensions?  Is it possible to update, remove and manage the extensions?


As a result of a problem I can not solve , I decided to reinstall Ubuntu , but before do this I want to save all the files I have on my hard drive from CD passing through " Ubuntu Live " The problem is that I had secured access to Ubuntu password and now from "ubuntu live" I'm not allow to save all files: on some folder ( moreover the most important ) I found a gray X and if I try to open them I get an error message : "This location could not be displayed . You do not hace the Necessary permission to view the contents of ....... "  After that, I tried with sudo nautilus  but unfortunately there was nothing to do, when I write it, the terminal return this    If I try to give again the command sudo nautilus, the response change    I tried to follow various guides from this forum where it's said to try to terminal with the following commands  sudo apt-get remove nautilus   sudo apt-get install nautilus   sudo apt-get install samba    but the result will not change

For some reason I can't boot my system. I get an error akin to Operating System Not Found.   I tried bootrepair, and that didn't work. So then I decided I would just save my personal files, wipe everything, and reinstall.   But in the live session, when I go to the /home directory, my username folder isn't there, instead it goes to the Live CD's desktop and other directories. Is there some other error occurring? Is there a way to recover the files?


When the centripetal force on an orbiting body disappears (e.g. if it the body is a ball and the force was exerted by a string and the string rips, or, more unrealistically, if the body is the earth and the sun suddenly disappeared), the body continues in linear motion. How is angular momentum conserved here?

I shall assume that the sun is at rest, so before the half mass disappear, the orbit of earth is an ellipse.


On php. How we use md5 encryption method? Suppose a login form. When we want an encrypted text we use  $encryptedtxt=md5('text');   Then we sent this $encryptedtxt to database. Now if we want this $encryptedtxt to compare with user new inputs to login , what should we do? If we should return text from encrypted form of it, how? Tnx.

It is currently said that MD5 is partially unsafe. Taking this into consideration, I'd like to know which mechanism to use for password protection.  This question,   suggests that hashing multiple times may be a good idea, whereas  suggests using salt.  I'm using PHP. I want a safe and fast password encryption system. Hashing a password a million times may be safer, but also slower. How to achieve a good balance between speed and safety? Also, I'd prefer the result to have a constant number of characters.   The hashing mechanism must be available in PHP It must be safe It can use salt (in this case, are all salts equally good? Is there any way to generate good salts?)   Also, should I store two fields in the database (one using MD5 and another one using SHA, for example)? Would it make it safer or unsafer?  In case I wasn't clear enough, I want to know which hashing function(s) to use and how to pick a good salt in order to have a safe and fast password protection mechanism.  Related questions that don't quite cover my question:


What alternatives could I use when displaying quotes " from my SQL Server database? Something that works like *_real_escape_string?  E.g.  $row['details'] has a value of "This is my quoted sentence"   Simply ECHOing this gives:  �This is my quoted sentence�   And I want it to go like this:  "This is my quoted sentence"

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


MWE:  \documentclass{article} \usepackage{enumitem} \newcommand{\bulletlabel}{\raisebox{0.2ex}{\small$\bullet$}}  \begin{document}  \begin{enumerate}[label=\bulletlabel, topsep=0pt, leftmargin=0.3in, rightmargin=0.3in]     \item One     \item Two \end{enumerate}  \end{document}   As you can see, I've parameterised my enumerate environment to get the formatting I want. I use this set of parameters fairly often in my document, together with 2 other sets of parameters.  Is there a quick way for me to replicate this without having to copy/paste or type it out every time? I don't want to redefine the default enumerate environment, as there are 2 other sets of parameters that I need to handle as well. I'm just looking for a quick way to do it.  I tried this:  \newcommand{\paramone}{label=\bulletlabel, topsep=0pt, leftmargin=0.3in, rightmargin=0.3in}   But when I use:  \begin{enumerate}[\paramone]   It fails because it processes it as one parameter rather than 4.  How can I achieve this?

I have defined the following simple environment:  \newenvironment{renumerate}{\begin{enumerate}\raggedright}{\end{enumerate}}   I wonder how the above can be modified to use with, say, the following:  \begin{renumerate}[label=\color{blue}10.\theenumi] \item blah \item blah \end{renumerate}   The options given in [] are not known in advance.


I submitted a paper with my co-author to a Springer Journal in the area of computational Mathematics.  It has been nearly a year now and we have not heard from the editor. There was no response for inquiries made every 3 months.  I  requested status from managing editor few weeks ago but still with no response. Given the length of the wait and the fact that the journal is the right avenue for our work, I was not sure what are the right steps ( wait more, withdraw and submit elsewhere?...)

I submitted a paper to an Elsevier journal in August and the status has been "with editor" ever since. I was concerned that it had not been sent for review for 4 months and I sent inquiries twice without getting any response. I am wondering if I should just withdraw my paper?


I've configured FileZilla server successfully (without SSL/TLS) by port forwarding:  -Modem (external ISP address): TCP 21, 990, 50000-50100 -> 10.1.10.10  -Router (external 10.1.10.10): TCP 21, 990, 50000-50100 -> 192.168.1.61 (server)  And allowing Windows Firewall TCP(and UDP) ports 21, 990 and 50000-50100. I also set FileZilla server to use a custom port range for passive mode (50000-50100)  However  As soon as I enable the following checkboxes in FileZilla server:   Enable FTP over SSL/TLS support (FTPS) Allow explicit FTP over TLS Disallow plain unencrypted FTP For PROT P to encrypt file transfers in SSL/TLS mode   The connection is made (accept the certificate), but the client fails at the MLSD command after entering passive mode.   Does explicit SSL/TLS use different ports? If I try implicit SSL (port 990) the connection isn't even made. I would settle for either type of secure connection working.

I have setup an FTP service in Windows Azure using this guide   The FTP Server works well when I connect without SSL when sitting at work behind my office firewall.  BUT when I try to connect with SSL (port 21, AUTH TLS - Explicit , CuteFTP), I get a timeout. When I do exactly the same at home, the connection works (SSL). What am I doing wrong? Is the SSL connection using other ports?  Authentication works fine, it's when the client sends the LIST command the timeout comes  STATUS:>    [11.02.2013 12:56:28] Using UTF-8. STATUS:>    [11.02.2013 12:56:28] This site can resume broken downloads. COMMAND:>   [11.02.2013 12:56:28] REST 0         [11.02.2013 12:56:28] 350 Restarting at 0. COMMAND:>   [11.02.2013 12:56:28] PBSZ 0         [11.02.2013 12:56:28] 200 PBSZ command successful. COMMAND:>   [11.02.2013 12:56:28] PROT P         [11.02.2013 12:56:28] 200 PROT command successful. COMMAND:>   [11.02.2013 12:56:28] PASV         [11.02.2013 12:56:28] 227 Entering Passive Mode (***,**,**,201,27,92). COMMAND:>   [11.02.2013 12:56:28] LIST STATUS:>    [11.02.2013 12:56:28] Connecting FTP data socket... ***.**.**.201:7004... ERROR:>     [11.02.2013 12:56:49] The connection failed due to an error or timeout.   I read something about trouble with FTPS and NAT but didn't quite catch it


The following code  if [ $a == "apple" ]; then     echo "True" else     echo "False" fi   outputs "True" ("False") if a="apple" (a="plum"). The comparison fails if one uses wildcards:  if [ $a == "appl"* ];   and is fixed if one replaces [ by [[:  if [[ $a == "appl"* ]];   What is the difference between [ and [[ in if statements?

Is there is any difference between these two.  [[ $a == z* ]]   and   [ $a == z* ]    Can I have an example where they would have different outputs?  Furthermore, how does the working of [[ ]] differs from [ ]?


Ubuntu 13.10, Saucy Salamander here. I am trying to install wireshark in order to monitor USB activity with a certain device. The problem is that wireshark does not have access to the USB bus (or any bus, for that matter, no interfaces show up).   they describe, that wireshark can be run either as root, or as an ordinary user. I tired executing dpkg-reconfigure wireshark-common but after the dialog, nothig happens, and I don't know why.   an alternative procedure for other Linux users (non-Debian) is outlined. I haven't tried it, as the dpkg method is the recommended one for Ubuntu and I would like to know what is going wrong.  Where should I look?

It's the first time I'm installing and configuring Wireshark in a rpm-based distro. In the past I've installed it properly on Ubuntu, Mint or Debian.  Don't know why, but it seems I cannot run it as standard user. I've done the process of creating the wireshark group and adding the user to that group and then change the group of dumpcap to wireshark, but no way, it doesn't work.  In .deb systems I haven't had any problem following such steps, so don't know what could be missing.  Thoughts?


I downloaded Ubuntu but Windows needs to know what to open it with. I am using a Vivaldi browser not Firefox.

I would like to see a full how-to guide on how to install Ubuntu.


Is it possible to prove Gödel’s 1st Incompleteness theorem without the use of self referential statements?  I have searched for various proofs of the first incompleteness theorem and all of them use some sort of self-reference or the other(usually indirectly however). Is this the only way to prove it?

For the proof of Gödel's Incompleteness Theorem, most versions of proof use basically self-referential statements.   My question is, what if one argues that Gödel's Incompleteness Theorem only matters when a formula makes self-reference possible?  Is there any proof of Incompleteness Theorem that does not rely on self-referential statements?


money = 0.56; money -= 0.50; // here the result is 0.06000000000000005 when actually i need it to be just 0.06 money -= 0.06  // and after this subtraction the result becomes 5.0306980803327406e-17 console.log(money); // 5.0306980803327406e-17   This totally messes up my logic when for example I compare "money" with the number 0.

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


There are several conjectures in Mathematics that seem to be true but have not been proved. Of course, as computing power increased, folks have expanded their search for counterexamples ever and ever upwards.  Providing a counterexample to a conjecture with a very large number would be interesting, but I cannot think of any non-trivial examples where a really large number has been found to disprove a (non-trivial) conjecture. I've seen plenty of large numbers serving as bounds to some value, but usually this is something known to be bounded (i.e. finite) anyway.  Out of curiosity, what's the largest counterexample you've seen to disprove a conjecture?

I just came back from my Number Theory course, and during the lecture there was mention of the Collatz Conjecture.  I'm sure that everyone here is familiar with it; it describes an operation on a natural number – $n/2$ if it is even, $3n+1$ if it is odd.  The conjecture states that if this operation is repeated, all numbers will eventually wind up at $1$ (or rather, in an infinite loop of $1-4-2-1-4-2-1$).  I fired up Python and ran a quick test on this for all numbers up to $5.76 \times 10^{18}$ (using the powers of cloud computing and dynamic programming magic).  Which is millions of millions of millions. And all of them eventually ended up at $1$.  Surely I am close to testing every natural number? How many natural numbers could there be?  Surely not much more than millions of millions of millions. (I kid.)  I explained this to my friend, who told me, "Why would numbers suddenly get different at a certain point?  Wouldn't they all be expected to behave the same?"  To which I said, "No, you are wrong!  In fact, I am sure there are many conjectures which have been disproved by counterexamples that are extremely large!"  And he said, "It is my conjecture that there are none! (and if any, they are rare)".  Please help me, smart math people.  Can you provide a counterexample to his conjecture?  Perhaps, more convincingly, several?  I've only managed to find one! (Polya's conjecture). One, out of the many thousands (I presume) of conjectures. It's also one that is hard to explain the finer points to the layman. Are there any more famous or accessible examples?


I understand the guidance on positioning text and numeric columns. I also have a column, though, that presents a boolean (Y/N) value. Is it appropriate to align it to the left as text, or right as numeric?

My understand is text should be left-aligned; dates, times, and numbers should be right-aligned; images should be centered.  What about Boolean strings "Yes"/"No"? My hunch says to center them.


I recently installed Ubuntu 14.04 on a Kingston 120 GB SSD. I plan on installing several programs, including Steam, that will take up quite a bit of space, so I installed, formatted, and partitioned a 1 TB HDD. Is it possible to change the default installation path of programs, or possibly even on a program by program basis? An older similar post suggested mounting an additional harddrive or partion as /usr or as /usr/share, but I am not sure if this is relevant to my issue. Thanks in advance.

When I install a software using apt-get it installs to default locations i.e to /usr/bin, /usr/lib, /usr/share and etc. For example when I install "Meld Diff Viewer" using  sudo apt-get install meld   and use whereis command to find its location, I get the following output  adnan@adnan-laptop:~$ whereis meld meld: /usr/bin/meld /usr/lib/meld /usr/share/meld /usr/share/man/man1/meld.1.gz   Is there any way to change the install location. Lets say if I want to install it in /usr/local/ can I do it using apt-get or aptitude? I know I can compile it from source and specify prefix option to configure script or make install but it would be better (and really easier) if I could do it using apt-get as I would be able to use uninstall, upgrade and other stuff that apt-get offers


I have the   replaceitem entity @a container.0 crossbow{display:{Name:"\"Paintball Cannon\"",Lore:["\"Put the fireworks in your offhand, and watch them go BOOM!\""]},Enchantments:[{id:quick_charge,lvl:3}]}"    command set up, but I do not know where to put the {unbreakable:1} tag to make the item unbreakable

I have two commands I'd like to combine into one, but I'm not sure how to go about combining them. Is this possible?   Here are the commands. They work individually, I just can't seem to get them to work together:  /give @p jukebox 1 0 {CanPlaceOn:["minecraft:melon_block"]}     /give @p jukebox 1 0 {display:{Name:"Box"}}   Can you help me to add one of the commands to the other one?


I need to know how to interpret each of the graphics.

I have a data set that has customerID and daily visits. This dataset records the number of times customers visited the site in a day.   customerID   TotalVisits  1            6  2            17  3            20  4            25   Just to explore the data further, I tried plotting the TotalVisits values in a box plot. The plot doesn't seem to have a lower whisker. q1=1 and there are no values between q1 and  q1-1.5(IQR). The plot has q1, q2 and q3. The minimum value and q1 are the same.   Is this why the boxplot doesn't have the lower whisker? Could you please help me with the interpretation? Is it correct to draw a boxplot without any whiskers?  [I am new to the site and I am not able to post the image.]


I'd like to restart the GUI in Ubuntu 18 (using the standard Gnome interface), without rebooting. How can I do this?  I've found both these questions ( and ) but none seem to apply to Ubuntu 18 (sddm doesn't even seem to exist anymore).

How can I restart X Window Server from the command line?  I'd really like to be able to restart my GUI without having to do a full system reboot.


Can I install Ubuntu on usb during installation by setecting "something else"? And is it safe for my usb somebody said it destroys your usb after a while?

If you are hurrying to reply, System → Administration → StartUp Disk Creator -- no, that's not what I'm talking about.   I want to try Ubuntu 11.04's Unity without touching my existing Ubuntu install.  To do this, I need to install the nVidia drivers first (sigh).  To do this, I need changes to persist a reboot.  To do this, I need to really install Ubuntu on a USB key.  How do you do that?    What I tried   I tried to make a USB key from , then boot from it, then choose "Install Ubuntu." The installer refused to install to the installation media itself. I tried, from my installed copy of Ubuntu:  sudo kvm /dev/sdb --cdrom .cache/testdrive/iso/ubuntu_natty-desktop-i386.iso   ...but the installer didn't detect the disk properly.


I just installed Ubuntu 13.04. I used Wubi so I could have a windows dual boot setup because I am new to Linux and wanted to be able to switch back to Windows (7) if need be.  Everything seemed to install properly.   I entered the initial information: installation size, drive, language, desktop envi, username, and password  I rebooted my computer and selected Ubuntu instead of windows, but when I enter my username and password (the same exact credentials I had typed in for the initial information window a few min. ago) it keeps giving me a wrong password error message.  I can log in via a guest account, but cant do much from that. I cannot connect to the internet except with Ethernet cord. From the guest account I cannot edit user accounts.  [one thing I did notice that I thought was odd is that on the initial information window I mentioned above I remember it saying Ubuntu 12.04 but when I went into thew guest account and clicked system information it said I had Ubuntu 13.04....]  I am new to Linux, but I'm not a computer idiot and do not know what the problem could be??

I've installed Ubuntu, but when it is loading it gives following error:  mount:can't read proc/mounts. Can't fount such file or directory   However, OS continues loading but when I try to enter system using my login/password, which I entered during installation, it fails to login.  Does someone know what is problem here? I've tried reinstall ubuntu several times, but problem still occurs.  Medium from I installed: Windows 7. Installed Ubuntu with wubi, where I chose separate disk G(NTFS file format), set installation size: 18GB, chose Ubuntu in dropdownlist, language English(GB) and set username and password.


I try to create swipe tabs view. But got an error within my code.   Here is my code:   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_third);      mAdapter = new MyPagerAdapter(getSupportFragmentManager());      mToolbar = (Toolbar) findViewById(R.id.app_bar);     setSupportActionBar(mToolbar);      mTabLayout = (TabLayout) findViewById(R.id.tab_layout);     mPager = (ViewPager) findViewById(R.id.pager);     mPager.setAdapter(mAdapter);     mTabLayout.setTabsFromPagerAdapter(mAdapter);     mTabLayout.setupWithViewPager(mPager);     mPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout)); }  public static class MyFragment extends Fragment {     public static final String ARG_PAGE = "arg_page";      public MyFragment() {      }      public static MyFragment newInstance(int pageNumber) {         MyFragment myFragment = new MyFragment();         Bundle arguments = new Bundle();         arguments.putInt(ARG_PAGE, pageNumber);         myFragment.setArguments(arguments);         return myFragment;     }      @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {         Bundle arguments = getArguments();         int pageNumber = arguments.getInt(ARG_PAGE);         TextView myText = new TextView(getActivity());         myText.setText("Hello, " + pageNumber);         myText.setGravity(Gravity.CENTER);         return myText;      } }  public class MyPagerAdapter extends FragmentStatePagerAdapter {     public MyPagerAdapter(FragmentManager fm) {         super(fm);     }      public Fragment getItem(int position) {         ThirdActivity.MyFragment myFragment = new ThirdActivity.MyFragment();         return myFragment;     }      @Override     public int getCount() {         return 10;     }      @Override     public CharSequence getPageTitle(int position) {         return "Tab" + position;     } }   I can't find how to fix it. the error is on line 85:   int pageNumber = arguments.getInt(ARG_PAGE);   Any suggestion? What should i add so it can work properly.  I've read this link         but can't get it why my code can return null. when i read the code it should return the value.   arguments.putInt(ARG_PAGE, pageNumber);   and i take the arg_page number. so the value should be there.  Thanks

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?


Here is a screenshot of my reputation for today:    I know about reputation cap, but as you see, it's not an issue. Why didn't I get reputation from this upvote?

Some questions and answers are marked Community Wiki and are owned by a community wiki user:  (In fact, this very question is one of them)  Why have Community Wiki posts? How do Community Wiki posts work? How does a post become a Community Wiki post? How can the Community Wiki status be removed from a post? How can I find Community Wiki posts?


I've been reading about risk ratios as typical measures in clinical settings. In the finance and credit literature, there is the weight of evidence (WoE) measure that is used to encode and study variables.   Is there a relationship between them? I read somewhere that the WoE is pretty much the log of the risk ratio, if you condition things properly, but I've been unable to prove that.

In credit scoring models, we use Weight of Evidence to create bins for continuous variables and Information value to filter out important variables. \begin{align} \text{WoE:} \qquad &\ln \frac{\text{Distr Good}}{\text{Distr Bad}} \cdot 100  \\[10pt] \text{IV:} \qquad &\sum_{i=1}^n \left( \text{Distr Good}_i - \text{Distr Bad}_i \right) \cdot \ln \frac{\text{Distr Good}_i}{\text{Distr Bad}_i} \end{align} Can someone help explain the intuition behind these formulas?


I want to create a List of strings in C#. These strings all come from this one:  <Functie><Titel><![CDATA[voorzitter]]></Titel></Functie><Functie><Titel><![CDATA[planner]]></Titel></Functie><Functie><Titel><![CDATA[barman1]]></Titel></Functie><Functie><Titel><![CDATA[barman2]]></Titel></Functie><Functie><Titel><![CDATA[barman3]]></Titel></Functie>   This string come from a soap respons. Here is my request:  using (Stream stream = request.GetRequestStream())         {             soapEnvelopeXml.Save(stream);         }         using (WebResponse response = request.GetResponse())         {             using (StreamReader rd = new StreamReader(response.GetResponseStream()))             {                 string soapResult = rd.ReadToEnd();                 string toBeSearched = "<tns:VoorkeurListResponse>";                 int ix = soapResult.IndexOf(toBeSearched);                  if (ix != -1)                 {                     string code = soapResult.Substring(ix + toBeSearched.Length);                     code = code.Substring(0, code.IndexOf("</tns:VoorkeurListResponse>"));                     List = code;                     System.Diagnostics.Debug.WriteLine(List);                      System.Diagnostics.Debug.WriteLine(soapResult);                 }             }         }     }   I want to get the data that is between the brackets, so my List would be: voorzitter, planner, barman1, barman2, barman3.  Could somebody help me with this problem?

Is there a simple method of parsing XML files in C#? If so, what?