I encountered this problem as well. In many cases I've seen that you must connect an internet cable to the laptop, install some drivers and you're done, but in my case, my laptop doesn't have a network cable input (ASUS X509FB). How can I solve this?  EDIT:  description: Wireless interface                    product: ASUS_X018D                    vendor: MediaTek                    physical id: 2                    bus info: usb@1:2                    version: ff.ff                    serial: HCAXJR19D032D9E                    capabilities: usb-2.00                    configuration: driver=rndis_host maxpower=500mA speed=480Mbit/s               *-usb:1                    description: Generic USB device                    product: USB2.0-CRW                    vendor: Generic                    physical id: 4                    bus info: usb@1:4                    version: 39.60 --            *-network UNCLAIMED                 description: Network controller                 product: RTL8821CE 802.11ac PCIe Wireless Network Adapter                 vendor: Realtek Semiconductor Co., Ltd.                 physical id: 0                 bus info: pci@0000:04:00.0                 version: 00                 width: 64 bits                 clock: 33MHz                 capabilities: pm msi pciexpress cap_list                 configuration: latency=0                 resources: ioport:4000(size=256) memory:b4300000-b430ffff         *-pci:4              description: PCI bridge              product: Intel Corporation              vendor: Intel Corporation              physical id: 1d.4              bus info: pci@0000:00:1d.4 --   *-network        description: Ethernet interface        physical id: 1        logical name: enp0s20f0u2        serial: ae:37:06:a1:dc:96        capabilities: ethernet physical        configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.93 link=yes multicast=yes

We just bought a Lenovo  (which is supposed to have the Intel 8265 for wireless). This laptop was bought in part because it is certified to run Ubuntu and as such to me at least it would make sense for things to work out of the box... but no such luck.  First, I installed Ubuntu 17.10 and after installation realised Wi-Fi was not working. I also tried Ubuntu 16.04 from a USB drive since that is the version of Ubuntu it is certified for, but no luck there either.  The wireless chip is not detected by lshw (or even lspci by the looks of it), ip link does not show a wireless interface, and the iwlwifi kernel module is not loaded at boot (I can load this myself using modprobe iwlwifi but this does not make Wi-Fi work). I think it is a combined Wi-Fi/Bluetooth chip, and Bluetooth does appear to work (or at least Bluetooth shows up in Gnome and rfkill list).  modinfo iwlwifi | grep 8265 shows me a file ending in -34 is supposedly loaded but only a file ending in -33 (and some other lower numbers) is present in /lib/firmware, if that helps).  I have also installed the Linux 4.14.9 kernel in an attempt to get things to work, but this did not resolve the issue either.  Further information  root@ThinkPad-E570:~# modinfo iwlwifi | grep 8265 firmware:       iwlwifi-8265-34.ucode root@ThinkPad-E570:~# rfkill list all 0: tpacpi_bluetooth_sw: Bluetooth     Soft blocked: no     Hard blocked: no 1: hci0: Bluetooth     Soft blocked: no     Hard blocked: no root@ThinkPad-E570:~# dmesg | grep iwl root@ThinkPad-E570:~# lspci -nnk | grep 0280 -A3 05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:c821]     Subsystem: Lenovo Device [17aa:c024]   Update  I just noticed that the laptop does not have an Intel wireless chip at all, but in fact has a Realtek one... which means that the  of the shop I bought this laptop at were not accurate... Sigh. Same problem stands, however, just with a crappier wireless chip.


I m getting ConcurrentModificationException but i dont really understand why.. When i use an iterator shouldnt it supposed to work fine ?  public void nextDay(){         int range = (10 - 0) + 1;          ListIterator<User> it = this.socialNetwork.getPeopleInNetwork().listIterator();             while(it.hasNext()) {              User user = it.next();                int random = (int)(Math.random() * range) + 0;             if(user.getFriends().size()<=25){                 try {                      this.socialNetwork.getPeopleInNetwork().add(user.addFriend(new UserImpl("new","user")));                     user.addFriend(this.socialNetwork.getPeopleInNetwork().get(random));                 } catch (IllegalArgumentException | UserAlreadyInFriendListException e) {                     logger.error(e.getMessage());                 }             }else{                 try {                     this.socialNetwork.getPeopleInNetwork().add(user.addFriend(new UserImpl("new","user")));                     this.socialNetwork.getPeopleInNetwork().add(user.addFriend(new UserImpl("new","user")));                     this.socialNetwork.getPeopleInNetwork().add(user.addFriend(new UserImpl("new","user")));                     user.addFriend(this.socialNetwork.getPeopleInNetwork().get(random));                 } catch (IllegalArgumentException | UserAlreadyInFriendListException e) {                     logger.error(e.getMessage());                 }              }         }     }

We all know you can't do the following because of ConcurrentModificationException:  for (Object i : l) {     if (condition(i)) {         l.remove(i);     } }   But this apparently works sometimes, but not always. Here's some specific code:  public static void main(String[] args) {     Collection<Integer> l = new ArrayList<>();      for (int i = 0; i < 10; ++i) {         l.add(4);         l.add(5);         l.add(6);     }      for (int i : l) {         if (i == 5) {             l.remove(i);         }     }      System.out.println(l); }   This, of course, results in:  Exception in thread "main" java.util.ConcurrentModificationException   Even though multiple threads aren't doing it. Anyway.  What's the best solution to this problem? How can I remove an item from the collection in a loop without throwing this exception?  I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.


I am new to Ubuntu. I can find my error log here in var/log/apache2/error.log. but i couldn't clear it. i tried to change the permission to edit the content. But couldn't achieve it.   Please help me to remove it. I have read some question previously asked. but it does-not help me .  this one I read .   Here is my terminal screen-shot:

When using sudo to allow edits to files, I regularly get 'permission denied'.  For example, my mouse is jittery and sluggish, so I want to disable polling:  sudo echo "options drm_kms_helper poll=N">/etc/modprobe.d/local.conf   I'm prompted for a password, and then get:  bash: /etc/modprobe.d/local.conf: Permission denied   So I tried to do a temporary change to disable polling by using:  sudo echo N> /sys/module/drm_kms_helper/parameters/poll   Yet again the system responded with:  bash: /sys/module/drm_kms_helper/parameters/poll: Permission denied   Any ideas?


I just noticed that some users do not have the "top X" blue box in their profile.  See for :        or :        While for  it works:        Also for :        I see this happening to some user profiles, but not others. It seems a bit random: I cannot find a pattern on when it is happening!

On , there is a "top x%" label:    But this is not shown for some users:    Why is that so? I don't see any settings to hide this.


At the moment I write macros without breaking them up, like so:  \NewDocumentCommand{\HC}{ o }{\IfNoValueTF{#1} {\emph{HC}\xspace}{\emph{HC}, p.#1\xspace}}   This obviously gets pretty hard to follow once things get longer. Examples on this site are always broken into separate lines, using % at the end of each line. I have never been sure what the rules are for how to do this effectively, or what the practice of arranging code in this way is. I feel that I am falling into a very bad habit by ignoring this. Is there a guide to this anywhere on this site or elsewhere, or is it just personal preference?

I have been using LaTeX for a long time now, but still all my document files look a bit messy. Now I want to get rid of this bad habit and get some order into my code.  That is why I am wondering whether there are any coding style guidelines for LaTeX. Not necessarily anything official. It could for example make recommendations on how to format your code with respect to:   Setting comments in the text/preamble Whether to highlight sections/subsections etc. by some comments How to indent environements How to organize your preamble to make it readable etc.   If nothing as such exists (yet), it would be great if you could just post how you do it if you think your code looks rather nice.


$$\sum_{k=0}^n \cos(\alpha+k\theta)= \cos\left(\alpha+\left({n\theta\over2}\right)\right)*{\sin\left({(n+1)*\theta\over2}\right) \over \sin({\theta\over2})}$$  I have worked the left summation out to a couple of terms but I am not seeing how they are going to come together to get the right side. I wish I was better at writing on this site so I could show exactly what I have written. I also have to prove the summation of the sine but if I can figure out the cosine one above the sine should fall from that.  Sorry for the notation. I copied and pasted exactly like it said to do.

Possible Duplicate:          Prove $$\cos(\alpha) + \cos(\alpha + \beta) + \cos(\alpha + 2\beta) + \dots + \cos[\alpha + (n-1)\beta] = \frac{\cos(\alpha + \frac{n-1}{2}\beta) \cdot \sin\frac{n\beta}{2}}{\sin\frac{\beta}{2}} $$


I am thinking of updating an Ubuntu server, and was wondering whether to update systemd or not. However, I am not certain how to inspect the contents of the systemd update. The output of apt list --upgradable shows:  systemd/xenial-updates 229-4ubuntu19 amd64 [upgradable from: 229-4ubuntu17] systemd-sysv/xenial-updates 229-4ubuntu19 amd64 [upgradable from: 229-4ubuntu17]   How do I inspect the contents of these updates to make sure I'm ok with what they are doing to my system?  Apologies if this is a basic question for the advanced Ubuntines here.

describes how to get the changelog for a given package. However, it's the whole changelog.  What I'd like is a way to see what will be changed in whatever I'm about to upgrade. For example, I was imagining something like:  $ sudo apt-get upgrade --show-changelogs Reading package lists... Done Building dependency tree        Reading state information... Done Calculating upgrade... Done The following packages will be upgraded:   foo     -- adds the bar feature for better snazziness     -- removes the deprecated baz feature  1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 8,864 kB of archives. After this operation, 285 kB disk space will be freed. Do you want to continue [Y/n]?    Unfortunately, I don't see anything like that in the man pages for apt-get. Does this or something similar exist?  UPDATE: I've written a  talking about apt-listchanges and Debian changelogs in a little more depth that incorporates some of the feedback in this question.


I'm thinking of gifting a drawing tablet to a person who uses Ubuntu. I had my eyes on the Huion Kamvas Pro 13 and I would like to know if it is supported before making a terrible mistake. However, I couldn't find any clear information online and the related questions here on AskUbuntu are quite outdated.

I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it?


The question is:  If $$A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\cdots+\frac{1}{1997.1998}$$ and  $$B=\frac{1}{1000.1998}+\frac{1}{1001.1997}+\cdots+\frac{1}{1998.1000}$$ then what is the value of $\frac{A}{B}$?   I could figure out that $A=\frac{1997}{1998}$, but I have no idea how to proceed with $B$. Could somebody help?  Thanks for any help :-)


How to find the indefinite integral $$\int \frac{dx}{1+x^{n}}$$  where n is a positive integer?

Well, this might be a really simple one. But still... What will be the soln. to --- \begin{aligned} \int\frac{1}{1+x^n} dx \end{aligned}  Is substituting \begin{aligned} 1+x^n \end{aligned} by tan z the correct step?  Thanks for the Help.


I updated my Windows 10 via:  2020-01 Cumulative Update for Windows 10 Version 1909 (KB4532695) and 2020-01 Cumulative Update for .NET Framework 3.5 and 4.8 (KB4534132)  Before the update, when clicking on the Windows start button in the bottom left corner, I could just start typing in anything and it would search through the Program Files etc., for example: Click on the Windows logo, type in update, and it would show "Windows Update".   Now, after the update, when I click on the Windows logo and start typing, it moves over to what looks like Cortana, and no matter what I type in it doesn't seem to search, and it doesn't show anything other than the box itself.   How do I restore the original search function when clicking on the Windows logo, without having to remove the new updates?

The Search menu on my Windows 10 suddenly stopped working. When I click the Search icon or type something in the Start menu, it just shows a blank search window.    I've tried rebuilding the index, SFC /scannow, DISM Restore, and creating a new local user account. None of them worked.   Windows 10 1909 build 18363.592.


Why is Java disabled in Chrome? Is it some security concern?  From the official :     Chrome no longer supports NPAPI (technology required for Java applets)   The Java plug-in for web browsers relies on the cross platform plugin architecture NPAPI, which has been supported by all major web browsers for over a decade. Google's Chrome version 45 (scheduled for release in September 2015) drops support for NPAPI, impacting plugins for Silverlight, Java, Facebook Video and other similar NPAPI based plugins.   But does anyone know why? How could it be dangerous for Chrome users with the latest version of the Java JRE installed?

Why is the Java plugin (JRE) is disabled in Chrome? It is some security concern?  From official Java website:     Chrome no longer supports NPAPI (technology required for Java applets)   The Java plug-in for web browsers relies on the cross platform plugin architecture NPAPI,   which has been supported by all major web browsers for over a decade.   Google's Chrome version 45 (scheduled for release in September 2015) drops support   for NPAPI,   impacting plugins for Silverlight, Java, Facebook Video   and other similar NPAPI based plugins.   But anyone knows why? How it could be dangerous for Chrome user with latest version of Java JRE installed?


The special items that were added with the gen 2 Pokemon are really hard to get.   I have hit hundreds of Pokestops and have only gotten a total of 3 special items, and a max of 2 at a time. I used the metal coat and then a few days later I got metal coat again. I also have 1 dragon scale. My husband has gotten only 2 special items and they were different from mine so it's not location specific as to which items you can get.   Has anyone looked at the code surrounding special items?   Has anyone had more than two at a time in their inventory?

Thanks to , I know that I can obtain the new items required for the new evolutions from PokéStops. My question is, how common are these items? I've spun about a dozen stops and not seen a single one yet. Most PokéStop items are more common than that, so I'm wondering if they are pretty rare, or if I've just been unlucky.


I want my private IP address 192.168.xxx.xxx to be fixed and do not change, Is it possible? I am using Ubuntu 14.04.  I need it to work even when I change the network? Thank's

I have configured network adapter of guest Ubuntu to work in a bridged mode so I could ssh to it from the host machine.   The problem is that the guest Ubuntu ip address keep changing.   Even though it changes  within a very short range 192.168.0.4-10 it is still takes time to configure Putty and other programs each time.  Is there a way to make the guest Ubuntu ip address to be static?  My guest OS has the full GUI.


I am passing integer object reference   public class Test1 {     public static void main(String args[]){         Integer x = new Integer(56);         Integer y = new Integer(34);         Test1 test = new Test1();         test.change(x,y);         System.out.println("Values inside main() after calling change method");         System.out.println("x :"+ x +"; y :"+y);     }     public void change(Integer x1, Integer y1){          x1 = 45;         y1 = 1000;         System.out.println("Values After Modification inside change method");         System.out.println("x1 :"+ x1 +"; y1 :"+y1);     } }   but there is no change in value of x and y ?? Please help...Thank you in advance. Here is the output.  Values After Modification inside change method x1 :45; y1 :1000 Values inside main() after calling change method x :56; y :34

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Basically I want to make a video with a moving picture that moves with a person in a video's head.

I downloaded an 80s cartoon intro (Jem and the Holograms; traditional cel animation) and I want to animate cutout photos of various family members' faces overtop the cartoon faces. Bonus points if I can apply some "worn out VHS tape" effect to the photo faces. Time permitting, I might even like to add some Terry Gilliam cutout jaw movement.  If I set up tracker points for the cartoon characters' eyes in the Movie Clip Editor, how do I get the photo face to follow these points, such that closely spaced markers indicate the photo face should be smaller/further away and vice versa, or approximate the head tilt like the popular "Elf Yourself" Christmas videos that were hot a few years ago? This seems doubly difficult since the cel animation has a lot of quick cuts and scene changes.


It is known, that the Cantor set is the subset of points of the segment $[0,1]$ allowing ternary expansion $0.a_1a_2\ldots$, where $a_i=0$ or $2,\; i\in {\mathbb N}$, neither of those values ($0$ or $2$) in period. In English edition of V.I. Bogachev's fundamental work Measure Theory vol 1, we read. 1.12.60$^◦$. Let $C$ be the Cantor set in $[0, 1]$. Show that $C + C := \{c_1 + c_2 : c_1, c_2 ∈ C\}$ $ = [0, 2]$,  $C − C := \{c_1 − c_2 : c_1, c_2 ∈ C\} = [−1, 1]$. Hint: the sets $C + C$ and $C − C$ are compact, hence it suffices to verify that they contain certain everywhere dense subsets in the indicated intervals, which can be done by using the description of C in terms of the ternary expansion. In ternary expansion $1/2=0.(1)$ (1 in period). The question is: How to show that there exist Cantor set poins $c_1=0.a_1a_2\ldots$, and $c_2=0.b_1b_2\ldots$ (where both $a_i,b_i$ are $0$ or $2$, for all $i\in {\mathbb N}$, none of them in period, such that $c_1-c_2=0.(1)$?

I am trying to prove that     $C+C =[0,2]$ ,where $C$ is the Cantor set.   My attempt:  If $x\in C,$  then  $x= \sum_{n=1}^{\infty}\frac{a_n}{3^n}$ where $a_n=0,2$  so any element of $C+C  $ is of the form  $$\sum_{n=1}^{\infty}\frac{a_n}{3^n} +\sum_{n=1}^{\infty}\frac{b_n}{3^n}= \sum_{n=1}^{\infty}\frac{a_n+b_n}{3^n}=2\sum_{n=1}^{\infty}\frac{(a_n+b_n)/2}{3^n}=2\sum_{n=1}^{\infty}\frac{x_n}{3^n}$$  where $x_n=0,1,2, \ \forall n\geq 1$.   Is this correct?


If I use:  \begin{Parallel}[c]{0.47\textwidth}{0.47\textwidth} \ParallelLText{paragraph 1 left} \ParallelRText{paragraph 1 right} \ParallelPar \ParallelLText{paragraph 2 left} \ParallelRText{paragraph 2 right} \ParallelPar \end{Parallel}   I get:  paragraph 1 left          paragraph 1 right paragraph 2 left          paragraph 2 right                     1   If I use:  \begin{Parallel}[p]{\textwidth}{\textwidth} \ParallelLText{paragraph 1 left} \ParallelRText{paragraph 1 right} \ParallelPar \ParallelLText{paragraph 2 left} \ParallelRText{paragraph 2 right} \ParallelPar \end{Parallel}   I get:                      1  paragraph 1 left                     2  paragraph 1 right                     3  paragraph 2 left                     4  paragraph 2 right                     5   What should I use in order to get:                      1  paragraph 1 left paragraph 2 left                     2  paragraph 1 right paragraph 2 right                     3   ? Can this be achieved with parallel? If not, what are the options?  Please let me specify that I'm starting to work on a book (+300 pages) that will have to be entirely in the desired form (even pages in one language and odd pages in another language; all paragraphs will have to be synchronized, e.g. paragraph#1_right will be the translation of paragraph#1_left).

It's common to set an old play (e.g. Shakespeare) with annotations on the left page and reference information on the right. I don't want to do this for a play, but I would like to set a document with annotations on one page and text on the facing page.  The catch is that I want to ensure that the annotations have parallel section spacing, because the length of the annotation may be longer or shorter than the corresponding section in the document, and I don't really want to make it so that you have to switch back and forth between documents.  That is, I would like it something like this:  +-----------------+    +-----------------+ | Heading         |    | Heading         | | -------         |    | -------         | | annotation      |    | this paragraph  | |                 |    | is long         | |                 |    |                 | | Heading 2       |    | Heading 2       | | ---------       |    | ---------       | | this annotation |    | short paragraph | | is really long  |    |                 | +-----------------+    +-----------------+   Does anyone know of a package that can do this, or an alternate way to achieve the objective of lining up the document and annotations?


I want to show that the geometric series $$1+r+r^2 + \cdots + r^n = \frac{r^{n+1} - 1}{r-1}, r \neq 1$$  I first started with the following using Gauss method:  $$S = 1+r+r^2 + \cdots + r^n$$   $$S=r^n + r^{n-1} + r^{n-2} + ... + 1$$  Adding both S's:  $$2S = (1+r^n) + (r+r^{n-1})+(r^2+r^{n-2})+...+(1+r^n)$$  Am I on the right track?  PS: I initially tried to follow  question, however, there was not enough to go on, so I attempted to do this on my own.     Update:  I originally assumed that I can use Gauss method which proved (when he was 10 years old!) $$\sum_{k=1}^nk= \frac{n(n+1)}{2}$$  but from user comments below, Gauss method cannot be applied here, as my questions is regarding a geometric sum not an arithmetic sum.

Why does the following hold:  \begin{equation*} \displaystyle \sum\limits_{n=0}^{\infty} 0.7^n=\frac{1}{1-0.7} = 10/3\quad ? \end{equation*}  Can we generalize the above to      $\displaystyle \sum_{n=0}^{\infty} x^n = \frac{1}{1-x}$ ?   Are there some values of $x$ for which the above formula is invalid?  What about if we take only a finite number of terms? Is there a simpler formula?     $\displaystyle \sum_{n=0}^{N} x^n$   Is there a name for such a sequence?    This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


Does a standard bike helmet offer any real protection when cycling offroad? Looking at other people cycling offroad, fullface helmets are quite rare. Although to me it looks like a standard helmet is almost useless (as well as on road, but even more offroad with all the branches and rocks everywhere). So, any reason fullface is not the standard?

It is possible to get a helmet that covers your entire head and face, and in theory would protect you against more kinds of falls. In particular, Why don't bicyclists wear them, and why do motorcyclists wear them?   I'm not asking whether helmets are a good idea in general. (Please try to answer this with complete answers, rather than the single-point style of the currently running helmet thread.)


When I go to  I get an error:  When I click advanced it says:  This server could not prove that it is www.askubuntu.com; its security certificate is from stackexchange.com. This may be caused by a misconfiguration or an attacker intercepting your connection. NET::ERR_CERT_COMMON_NAME_INVALID  This is on Google Chrome - Ubuntu 14.04, but has been reproduced on Firefox - all Ubuntu.  Just plain old  is fine.  Edit: Now working sometimes, but not always. Same error.

So it looks like Stack Exchange now supports HTTPS (to some extent). Which is awesome! But there are a few problems, the main one being that some content is delivered over the CDN, which is plain HTTP. This causes browsers to complain about "unsecured content":


Paladin, Mounted Combatant feat, Great axe, riding a Warhorse.  I'd like to ride 30ft to the mob, bash him with my axe, have the steed disengage, and ride 30ft back.  Can I do this?  Jeremy seems to be confusing me.  :)  Spell text: "Your steed serves you as a mount, both in combat and out, and you have an instinctive bond with it that allows you to fight as a seamless unit."  A seamless unit, eh?  Sounds good so far....  Mounted Combat in PHB: "The initiative of a controlled mount changes to match yours when you mount it. It moves as you direct it"    OK, so it has the same initiative score as me, this isn't looking good...  Jeremy Tweet from 2017: "A rider and a controlled mount have separate turns, but they have the same initiative, which means you decide which one goes first."  SEPARATE TURNS.  So much for a seamless fighting unit.  Can't ride up, bash, disengage, and ride away.  Dragon Talk with Jeremy Crawford from 2018: "If you control the mount, the creatures initiative changes to your initiative. You're now acting as a unit. It still has a turn, but it's turn OVERLAPS with yours, it gets its move, its moving on YOUR turn, so then far easier for your character to co-ordinate with the mount, and it's actions are limited to dodge/dash/disengage. It won't attack. The fact that it can disengage means it can move without opportunity attacks, and the beauty of it acting on your turn, with its turn overlapping with yours, is that also your movement is still free and your actions are still available. So it's a movement and action extension for the rider. A really powerful advantage. Even though it gives up ability to attack, you gain all this on your turn all this potential movement, and a free dodge/dash/disengage, and a dash means even more movement."  This contradicts his earlier tweet, and goes further than the PHB.  What's the actual facts?

From "Controlling a Mount" on p.198 of the Player's Handbook:     The initiative of a controlled mount changes to match yours when you mount it. It moves as you direct it, and it has only three action options; Dash, Disengage, and Dodge. A controlled mount can move and act even on the turn that you mount it.   Does this mean that the rider and mount share a single turn?


I accidentally closed the panel that has a red circle (I dont know the name of it lol). I had to close everything and load the project again and untick the 'load UI' to restore that panel again. Is there a shortcut to open/close it similar to properties and toolbar panel?      I tried the answers from the duplicate but I'm talking about specifically the panel on the right side with the red circle on it. I'm just wondering if it has a shortcut button like the toolbar T and properties N panel.

I'm stuck in full screen in the node editor. Escape isn't working, and I have no menus and no idea how to leave except to quit Blender and reopen the program.


Hi StackExchange community, I would like to ask how to perform a statistic test on the sum of coefficients in regression analysis in R, possibly using a Wald test. As per my data, I have the historical price of gold and a dummy variable that represents whether a certain date indicating economic uncertainty or not. The equation is shown below: Stock Return(t) = α + Gold Return(t) + (Gold Return(t) x Dummy(t)) + e or R(t) = α + β1Xi + β2XiXii + e I would like to see whether the sum of β1 + β2 is statistically significant, possibly using t-stat and Walt tests. Thank you very much for your consideration in advance.

I have multiple regression with, say 3 independent variables: $Y=B_0+B_1x_1+B_2x_2+B_3x_3$ I would like to test if $B_2+3B_3$ is significantly different from zero, i.e.  $$H_0: B_2+3B_3=0$$ $$H_1: B_2+3B_3\neq 0$$ Can you please help to find appropriate way to test for significance of linear functions of two coefficients as in above example.  Many thanks in advance.


I have a black and white image which serves as a template for my game. Non selected country borders are white, and selected country borders should be outlined by solid black lines.  Each country border is represented by a mesh which I position over a country.  Meshes are created in Blender using BezierCurves and convert to mesh option.  Is it possible to create a material in a simple manner, which would make my 2d mesh render as solid black lines, to achieve select/deselect effect?  I'm quite new at Blender and didn't manage to achieve it via FreeStyle component for mesh outlining.  QUESTION UPDATE  Managed to render solid lines in Blender render view.    When you export your mesh from Blender, is your material exported also?  Because when I imported the mesh into Unity, the mesh was not rendered.  Meshes without faces aren't visible in Unity, so I expected my material to make the mesh visible.  Every advice will be appreciated :)  CONCLUSION  The outline effect can be achieved in Blender relatively easily, but you cannot export it in my case.  The mesh must be shaded with a Unity compatible shader and materials used must be built  inside Unity in most cases.  Sadly, free version of Unity doesn't allow writing shaders in OpenGL, Unity shader syntax must be used.  Thx, everyone!

I have a schematic of a raspberry pi that is completely flat, no solid faces, just connected vertices.  Is it possible to render these lines somehow, so that it looks like a 2D drawing?  Maybe with freestyle?


I have to show that, if the title is true, then f is constant.  I can't find the way to approach this. I thought using the fact that, since f is whole, $f(z)=\sum_{n=0}^\infty a_nz^n$ for some $a_n\in\mathbb{C}$. Then $f(0)=a_0=f(z_0)=f(z_1)$. I wanted to show that $g(z) = f(z)-a_0$ trying to build a convergent sequence of zeros of $g(z)$ using the $z_0$ and $z_1$ so I could use the identity principle.   I tried it less, because I couldn't find a way to use it, but tried showing that using the $g$ defined above, $g^{(n)}(0)=0$ $\forall n\in\mathbb{N}$  Thanks in advance

Let $f: \Bbb C \to \Bbb C$ be an entire (analytic on the whole plane) function such that exists $\omega_1,\omega_2 \in \mathbb{S}^1$, linearly independent over $\Bbb R$ such that: $$f(z+\omega_1)=f(z)=f(z+\omega_2), \quad \forall\,z\in \Bbb C.$$Prove that $f$ is constant.   The intuition seems clear to me, we have the three vertices of a triangle given by $0$, $\omega_1$ and $\omega_2$. All points in the plane are one of the vertices of that triangle under a suitable parallel translation. The constant value will be $f(0)$, fine. Throwing values for $z$ there, I have found that $$f(n\omega_1) = f(\omega_1) = f(0)=f(\omega_2) = f(n\omega_2), \quad \forall\, n \in \Bbb Z.$$  I don't know how to improve the above for, say, rationals (at least). Some another ideas would be:   Checking that $f' \equiv 0$. I don't have a clue of how to do that. Write $w = a\omega_1+b\omega_2$, with $a,b \in \Bbb R$, do stuff and conclude that $f(w) = f(0)$. This approach doesn't seem good, because I only have a weak result with integers above. Finding that $f$ coincides with $f(0)$ on a set with an accumulation point. This seems also bad: the set on with $f$ coincides with $f(0)$ by which I found above is discrete.    Nothing works and this is getting annoying... And I don't see how analyticity comes in there. I'll be very thankful if someone can give me an idea.  (On a side note.. I know that this title is not informative at all. Feel free to edit if you come up with something better.)


I need some help, I'm learning by myself how to deal with maps in Java ando today i was trying to get the sum of the values from a Hashmap but now Im stuck.  This are the map values that I want to sum.  HashMap<String, Float> map = new HashMap<String, Float>();  map.put("First Val", (float) 33.0); map.put("Second Val", (float) 24.0);   Ass an additional question, what if I have 10 or 20 values in a map, how can I sum all of them, do I need to make a "for"?  Regards and thanks for the help.

If I have an object implementing the Map interface in Java and I wish to iterate over every pair contained within it,  what is the most efficient way of going through the map?  Will the ordering of elements depend on the specific map implementation that I have for the interface?


I have a vacuum sealed 8 lb. beef tenderloin that was in my refrigerator.  The door was not closed completely and the refrigerator warmed to 42 degrees just at the beginning of the danger zone.  The refrigerator could have been at that temp for 6 to 8 hours.  The tenderloin was in the middle back of a bottom shelf.  Is this safe to use?

If I left food out of the refrigerator for some period of time, is it still safe? If I left it out too long, can I salvage it by cooking it more?


I searched for this error on StackOverflow but any topic seens to solve my problem. I have this code that opens a .txt file and inicialize objects variables and this error appears.  public void lerDoArquivo() {     try {         FileReader ler = new FileReader("Menu_de_itens.txt");         BufferedReader reader = new BufferedReader(ler);         String linha;          while ((linha = reader.readLine()) != null) {             processaEntrada(linha);         }          reader.close();     }      catch (IOException e) {         e.printStackTrace();     }   }   This is my stracktrace:  Exception in thread "main" java.lang.NullPointerException     at java.io.FileInputStream.<init>(FileInputStream.java:130)     at java.io.FileInputStream.<init>(FileInputStream.java:93)     at java.io.FileReader.<init>(FileReader.java:58)     at ItemMenuDAOTxt.lerDoArquivo(ItemMenuDAOTxt.java:22)     at ItemMenuDAO.<init>(ItemMenuDAO.java:16)     at ItemMenuDAOTxt.<init>(ItemMenuDAOTxt.java:14)     at ControleDeMenu.<init>(ControleDeMenu.java:21)     at FastFoodOO.main(FastFoodOO.java:11)

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


I made a site locally and when I uploaded it to the hosting server, it worked fine except when I went to edit some content type. It showed this error:  The website encountered an unexpected error. Please try again later.   It was showing nothing except the above error. To get more error output, I added a few lines to my index.php file (these lines were added right after the first line):   error_reporting(E_ALL); ini_set('display_errors', TRUE); ini_set('display_startup_errors', TRUE);   The error output was now showing this error:      Fatal error: Uncaught exception 'PDOException' with message   'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away' in   /home/a2682242/public_html/includes/database/database.inc:2171 Stack   trace: #0   /home/a2682242/public_html/includes/database/database.inc(2171):   PDOStatement->execute(Array) #1   /home/a2682242/public_html/includes/database/database.inc(683):   DatabaseStatementBase->execute(Array, Array) #2   /home/a2682242/public_html/includes/database/database.inc(2350):   DatabaseConnection->query('SELECT expire, ...', Array, Array) #3   /home/a2682242/public_html/includes/lock.inc(167): db_query('SELECT   expire, ...', Array) #4   /home/a2682242/public_html/includes/lock.inc(146):   lock_may_be_available('theme_registry:...') #5   /home/a2682242/public_html/includes/theme.inc(449):   lock_acquire('theme_registry:...') #6   /home/a2682242/public_html/includes/bootstrap.inc(446):   ThemeRegistry->set(Array) #7 [internal function]:   DrupalCacheArray->__destruct() #8 {main} thrown in   /home/a2682242/public_html/includes/database/database.inc on line 2171   The site was working fine locally. I am not having much clue as to where the problem is. Is it some problem with the mysql server setting of my hosting provider? Or something else?

Possible Duplicate:          My website is moved from localhost to virtual hosting and after 1 week I receive an error 2006 2006 MySQL server has gone away. Now I can create/edit content but not content types and cannot clear the cache, I see white screen in this case. My hoster said that the max_allowed_packed size is only 1M and I cannot change it.   Is there a way to fix this error?    I deleted content types I don't use now and the problem has gone away... And now I can also clear the cache and edit other content types. What it was I cannot understand, it's beyond me


Lets say I want to download the 'Full GNOME Desktop Environment, with extra components' in the image below. What is the name of the package? is it 'gnome' or 'Full GNOME Desktop Environment, with extra components' or ...?

Hello I want to remove software (for example transmission) using Terminal. How can i find the package name for the software ?


I recently (yesterday) followed  and noticed that I'm not in the list of followers: and the followers count is 19 which is exactly the number of user in that list (without me). Am I missing something? (cached?)

I know of one person who is following my proposal who doesn't show up on the proposal webpage.    My proposal is for quantitative finance: .  It shows 19 people following the proposal (on the side of the page), and the total listed at the top of the page is 19 followers.  Yet one user is not listed: .  This makes me wonder if other followers are also not being counted?


when I updating with sudo apt-get update , I  got this:  N: Ignoring file '20auto-upgrades.ucf-dist' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension     W: The repository 'http://ppa.launchpad.net/lucid-bleed/ppa/ubuntu xenial Release' does not have a Release file.     N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.     N: See apt-secure(8) manpage for repository creation and user configuration details.     E: Failed to fetch http://ppa.launchpad.net/lucid-bleed/ppa/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found     E: Some index files failed to download. They have been ignored, or old ones used instead.   my question is:   What is this error and how do I understand it. What should I do to solve this problems.

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


I am attempting to add a value to a list at a specific index, which according to everything I've read, should be do-able with List's Insert() method.  Except I'm getting the exception "Index must be within the bounds of the List. Parameter name: index`  Here is my complete sample code.  class Program {     static void Main(string[] args)     {         MyList myList = new MyList();     } } class MyList : List<int> {     public MyList()     {         this.Capacity = 2;         this.Insert(1, 0);     } }   Is the only option to change to a nullable list type and call .Add(null) for each index and not use Insert()?

.NET offers a generic list container whose performance is almost identical (see Performance of Arrays vs. Lists question). However they are quite different in initialization.   Arrays are very easy to initialize with a default value, and by definition they already have certain size:  string[] Ar = new string[10];   Which allows one to safely assign random items, say:  Ar[5]="hello";   with list things are more tricky. I can see two ways of doing the same initialization, neither of which is what you would call elegant:  List<string> L = new List<string>(10); for (int i=0;i<10;i++) L.Add(null);   or  string[] Ar = new string[10]; List<string> L = new List<string>(Ar);   What would be a cleaner way?  EDIT: The answers so far refer to capacity, which is something else than pre-populating a list. For example, on a list just created with a capacity of 10, one cannot do L[2]="somevalue"  EDIT 2: People wonder why I want to use lists this way, as it is not the way they are intended to be used. I can see two reasons:   One could quite convincingly argue that lists are the "next generation" arrays, adding flexibility with almost no penalty. Therefore one should use them by default. I'm pointing out they might not be as easy to initialize. What I'm currently writing is a base class offering default functionality as part of a bigger framework. In the default functionality I offer, the size of the List is known in advanced and therefore I could have used an array. However, I want to offer any base class the chance to dynamically extend it and therefore I opt for a list.


I am dealing with the following exercise     A set $\mathcal M$ in a normed linear space $\mathcal R$ is said to be convex if $\mathcal M$ contains all elements of the form $\alpha x + \beta y$, where $\alpha, \beta \geq 0$, $\alpha+\beta=1$, provided that $\mathcal M$ contains x and y. Prove that the set of all elements $x \in \mathcal R$ satisfying the inequality $\|x-x_0 \| \leq c$, where $x_0$ is a fixed element of $\mathcal R$ and $c > 0$, is convex.   Assume $\|x-x_0 \|\leq c$, and $\|y-x_0 \| \leq c$, we have to proof that   $$\| \alpha x + (1-\alpha) y - x_0 \| \leq c.$$  By the triangular inequality,   $$\begin{align*}\| \alpha x + (1-\alpha) y - x_0 \| &  \leq \| \alpha x \| + \|(1-\alpha) y - x_0 \| \\ &  \leq \| \alpha x \| + \|(1-\alpha) y \| +\|- x_0 \| \\ & \leq |\alpha| \| x \| + |(1-\alpha)| \| y \| +\| x_0 \| \\ & = c.\end{align*}$$  Is it enough for proof the theorem? If not, what path should I take?

If $(X,\|\cdot\|)$ is a normed linear space, then how to show any ball $B(x,r)$ is convex? I know that if $x,y\in A\subset V$ then $[x,y]\subset A$, where $A$ is a convex subset of vector space $V$ and $[x,y]=\{(1-t)x+ty\mid 0\leq t \leq 1\}$. Please give me some hint.  I tried the following:  Claim. $[a,b] \subset B(x,r)$ Let $a,b \in B(x,r).$ Then I get $\|x-a\|<r$ and $\|x-b\|<r$.  Is it right?


Are there arbitary larger numbers of the form $a^b$ with positive integers $a,b>1$ and $a\ne 0\mod 10$ NOT containing all digits ?   Here :    is either a very similar or the same question, but the question is so old that I decided to restate it.  My current best example :     The number $1955^{39}$ has $129$ digits, but does not contain the digit $1$.   If we assume that the digits are uniformly distributed in $[0,9]$ and considering the growth of the non-trivial powers, can we expect that we have enough chances to get , lets say , a $1000$-digit example ?   In other words, are there enough non-trivial powers with a given decimal-expansion-length, that we can expect that the answer to the question is yes ?

Let $m>1$ be a natural number with $m \not\equiv 0 \pmod{10}$  Consider the powers $m^n$ , for which there is at least one digit not occurring in the decimal representation.  Is there a largest $n$ with the desired property for any $m$? If so, define $n(m)$ to be this number.  Examples :  $$m=2 \rightarrow 2^{168} = 374144419156711147060143317175368453031918731001856$$  does not contain the digit $2$.  All the powers above up to $2^{10000}$ conatin all the digits, so  $2^{168}$ seems to be the biggest power with the desired property.  $$m=3 \rightarrow 3^{106} = 375710212613636260325580163599137907799836383538729$$  does not contain the digit $4$.  All the powers above up to $3^{10000}$ contain all the digits, so $3^{106}$ seems to be the biggest power with the desired property.  So, probably $n(2)=168$ and $n(3)=106$ hold.  Is $n(m)$ defined for any $m$, and if yes, can reasonably sharp bounds be given?


I am new to PowerShell and I am stuck with a script to parse CSV document to identify if the emails are in proper format or not. My script does execute but instead of filtering records with invalid email it exports all records with the selected columns.  Please suggest as what I am missing.  $sourceFile = "d:\rvcc.csv" $targetFile = "d:\LMI-Invalid_Users_{0:yyyyMMMdd-HHmm}.csv" -f (Get-Date)  $validemailDomain1 = "^[a-z]+\.[a-z]+@stu.raritanval.edu$" $validemailDomain2 = "^[a-z]+@stu.raritanval.edu$" $validemailDomain3 = "^[a-z0-9]+@stu.raritanval.edu$" $blankemail=""  Import-CSV $sourceFile | % {     # The big blue bar:  Or Verbose text: Write-Verbose "Checking:         $($_.EmailAddress)"     Write-Progress -Activity "Checking user" -Status $_.EmailAddress     If ($_.EmailAddress -NotMatch $validemailDomain1 -or              $_.EmailAddress -NotMatch $validemailDomain2 -or             $_.EmailAddress -NotMatch $validemailDomain3 -or                 $_.EmailAddress -NotMatch $blankemail) {         $_ | Select-Object EmailAddress, FirstName, LastName, UserType, School_Id     } } | Export-CSV $targetFile -NoTypeInformation

Over the years I have slowly developed a  that validates MOST email addresses correctly, assuming they don't use an IP address as the server part.  I use it in several PHP programs, and it works most of the time.  However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs).  What is the best regular expression you have or have seen for validating emails?  I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.


I have and Excel file that I converted to a CSV file. Apparently there are two kinds of spaces in this file, the regular space and a non-breaking space (my assumption).  When saving the data to the database the non-breaking space gets saved as a black diamond with a question mark (�).  I've been reading around as this probably has solutions already but when I try them, nothing is happening.  Using the mb_substr approach:  $name = !empty($data[0]) ? mb_substr($data[0], 0, mb_strlen($data[0]), "UTF-8") : null;   Using the str_replace approach:  $name = !empty($data[0]) ? str_replace("&nbsp;", " ", $data[0]) : null;   I've been pulling my hair out with this one for a couple of hours now so if anyone could help me out, I highly appreciate it.  EDIT  I'm using Oracle for the database and here are the Character Sets defined:  NLS_CHARACTERSET       = AL32UTF8 NLS_NCHAR_CHARACTERSET = AL16UTF16   Here's a sample data:  , W.R.,  The space before W is the character that gets transformed into the question mark.

I'm writing a php program that pulls from a database source. Some of the varchars have quotes that are displaying as black diamonds with a question mark in them (�, , I assume from Microsoft Word text).  How can I use php to strip these characters out?


I am trying to learn discrete mathematics on my own and have been reading Rosen's discrete math textbook, there is one step in his proof that I do not understand.  Where $<2*k!$ becomes $(K + 1)K!$  he states that $2 < k + 1$ but how is he determining that?  I have attached an image of the proof for viewers to see exactly, it is the second last line of the inequalities.

Im trying to solve the following question         In the second step  where do they get $k!=2^k-1?$


I'm curious if it's possible to install Ubuntu on a blank HD over the network. This is an HP windows home/media server (hp ex490), with no CD/DVD rom. The server doesn't seem to respond to a USB monitor, keyboard or mouse.  I feel like there's information out there already on this, but I come up empty on Google.

I would like to install Ubuntu  for almost 120 users. But it's very difficult in using USB and drives.  Any suggestions?


I would like to be able to preview and capture photos from two cameras simultaneously, and download them to my computer. Being able to keep track of which photos were from which camera is also a must.  I haven't bought the cameras yet, and I do not have any requirements as to which cameras are supported (it seems the packages above only support Canons). On the other hand I need a digital camera with 1024*1280 pixel resolution.  I also want to control the capturing step and frequency with software on my computer.   My requirement is about 20 pictures per minute.  What's the best model camera and software for this purpose?  And how I can connect these camera to my computer?

I have 10 Canon 5DmkII cameras which I want to fire simultaneously... How can I accomplish this task repeatedly and reliably?  NOTE: Although I mention 10 cameras, it will be a 'super bonus' if the solution is scalable to n cameras...


At the end of season 2 of Stardust Crusaders, the blood from Dio's corpse was transfused back to Joseph Joestar. However, as seen before in the series, the contact of Dio's blood with a corpse makes the corpse a Vampire. It was also explicitly stated that Dio's body was still not "dead". Then why did this not happen to Joseph?

At the end of JoJo season 3:  episode 48:   Dio Brando killed Joseph Joestar using 'The World'. Later on, Dio drained his blood entirely and left Joseph Joestar as a husk.  However, Jotaro was able to revive   Joseph by transferring blood from Dio's dead body into his Grand Dad. ()  What I'm trying to understand though is why   Joseph did not turn into an undead vampire.  Because I remember the episode before that, Dio had previously used his blood   to turn  into a vampire (the one with the "self-eating" Stand).


I can't understand when I need one and two backward slashes \.  First, see an example:  const rxHttps = new RegExp("\/"); console.log(rxHttps.test("/")); // true  const rxQuestion = new RegExp("\\?"); console.log(rxQuestion.test("?")); // true  const rxAnotherQuestion = new RegExp("\?"); // Uncaught SyntaxError: Invalid regular expression: /?/: Nothing to repeat   In the above example, to use a character /, it needs just one \.  However, ? needs two \, or SyntaxError occurs.  This is really confusing. I can't make heads or tails of it.  Why are they different? Am I misunderstanding?

I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps.  It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps?


I am working with a $pq$ group. Where $p=7,q=11$.   I have so far managed to prove that such a group is cyclic and hence abelian.   My question asks what is this group isomorphic to and I don't really know. I do remember learning that we can classify all finite abelian groups into direct products of cyclic groups but I don't remember the specifics sorry.   As a guess I would think maybe our group of order $77$ is either isomorphic to $\mathbb{Z}_{77}$ or maybe $\mathbb{Z}_{7} \times \mathbb{Z}_{11}$ but I really don't know how to show this?

I don't know about the Sylow Theorems.  But I have been wondering about a proof of the fact that a group or order $pq$ where $p$ and $q$ are distinct primes must be cyclic. I can't quite work out the details, but here is the general idea. I would like help with filling in details. I assume that it is already known that $G$ has subgroup(s) of order $p$ and subgroup(s) of order $q$.  If $G$ is a group of order $pq$ ($p\neq q$), then I know that $G$ has a subgroup $H$ of order $p$ and a subgroup $K$ of order $q$. Then $H\simeq \mathbb{Z}_p$ and $K\simeq \mathbb{Z}_q$.   But then $H\oplus K \simeq \mathbb{Z}_{pq}$, so I would think that $H\oplus K \simeq G$. I guess one could do an internal direct product instead of an external direct product, but I don't know that $H$ and $K$ are normal subgroups.  I am asking for help completing this argument.  Edit: I see from the comments below that I might need to assume that the smaller prime does not divide the larger prime minus $1$. Or maybe it is enough to assume that the primes are greater than or equal to $3$ (Still distinct).


I've been using Xenial 16.04 and I'm thinking of installing 14.04 alongside the existing one so that I can do dual boot. Is this possible? And if so, how can I do it? I'm afraid that I might blow off my Xenial because I've never tried dual booting before.. I would really appreciate your help.

I have a dilemma and I don't know what to do.   Currently I have Ubuntu 14.04 64 bit installed along side Windows 7 64 bit and everything works wonderfully.   I recently started a course about Assembly on Linux and the professor recommended downloading Ubuntu 12.04 32 bit.   I downloaded the iso file and loaded it on to a USB.   When I first installed Ubuntu 14.04, it gave me the following 3 options:  1) install Ubuntu alongside Windows  2) delete Window and install Ubuntu 3) Something Else   I choose the first option. However, when I attempted to install Ubuntu 12.04 32bit along side Ubuntu 14.04 64 Bit and Windows 64 bit, the first option was gone. Instead I was given the following 3 options:  1) Delete 14.04 and install 12.04 in its place  2) Delete both 14.04 and Windows 7 and install 12.04 as replacement  3) Something Else   My question is this: is it advisable to install Ubuntu 12.04 32 bit along side Ubuntu 14.04 64 bit and Windows 7 as the Ubuntu Installer no longer gives me this option? Should I just go ahead and replace 14.04 with 12.04 for the duration of time that I would need it. I don't want to delete 14.04 but I will if need be. I also like the current Dual boot option Ubuntu has put in place so if making a 4th partition through way of "Something Else" would delete that, I would much rather delete 14.04 to make room for 12.04. Again my preference would be to have Ubuntu 12.04 32 bit appear alongside Ubuntu 14.04 64 bit and Windows 7 when I boot my computer, but short of that, I would settle for Ubuntu 12.04 32 bit appearing alongside Windows 7 for the time being. I look forward to your advice.


Error mounting /dev/sda3 at /media/dany/Data: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sda3" "/media/dany/Data"' exited with non-zero exit status 14: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. Failed to mount '/dev/sda3': Operation not permitted The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


The statement $$\forall x \in \mathcal{R} \exists n \in \mathcal{N} (n>x)$$ Is true, but $$\exists n \in \mathcal{N} \forall x \in \mathcal{R} (n>x)$$ Is false.  Why does reversing the order of the quantifiers cause the first statement to become false?

I'm working with the universal and the existential quantifiers and I was wondering is there an order of operations that applies to them? What is the difference between   $(\forall x)P(x)(\exists x)Q(x)$  And  $(\exists x)Q(x)(\forall x)P(x)$  Lets say we have this relationship  (a) $[(\forall x)P(x) \vee (\exists x)Q(x)] \implies (\forall x)[P(x) \vee Q(x) ]$


Here's the scenario. I have a HP laptop in which I installed Windows 10 Technical Preview a few months ago. Now, when I tried to turn it ON, it gave me an error "Your PC/device needs to be repaired", error 0x0000428. What I exactly want to do is, I want to format my entire hard drive so that I can reinstall Windows 7 in it but I don't know how to format it as I am unable to do anything with that error code in my laptop. I don't have disc for Windows 10 Technical Preview.

Is there a Disc Formatter out there that i can boot into using a CD and format my Harddrive.  I know i could use fedora CD but i was wondering if there is one out there that will make sure the data is actually gone and not just there links.


Let's say I have two Minecraft worlds and 20 mods. Can I make not enough items work with both the worlds but the other mods only work in the other world?

I have lots of mods installed on my Minecraft client. How can I make certain mods only work in certain worlds?  For example, how can I make the train mod work only for one of my worlds not the others and have BuildCraft work for all my worlds except the one with the train mod?


I'm seeing a spacing issue under Achievements on iOS mobile Safari:    Is this a know issue?   Device: iPhone 6 OS Version: Version 9.1 (Build 13B143)

There is some weird spacing on the mobile web site:    Additionally, the main font color has changed from black to yellow:    Can this be fixed please?


My code structure:  /foo     __init__.py     bar.py   init.py  import bar eval("import bar")   It raises SyntaxError when execute the second line.  >>> import foo Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "foo/__init__.py", line 2, in <module>     eval('import bar')   File "<string>", line 1     import bar          ^ SyntaxError: invalid syntax   I am confused because I would expect behaviors of these codes should be the same.

I'm writing a Python application that takes as a command as an argument, for example:  $ python myapp.py command1   I want the application to be extensible, that is, to be able to add new modules that implement new commands without having to change the main application source. The tree looks something like:  myapp/     __init__.py     commands/         __init__.py         command1.py         command2.py     foo.py     bar.py   So I want the application to find the available command modules at runtime and execute the appropriate one.  Python defines an __import__ function, which takes a string for a module name:     __import__(name, globals=None, locals=None, fromlist=(), level=0)      The function imports the module name, potentially using the given globals and locals to determine how to interpret the name in a package context. The fromlist gives the names of objects or submodules that should be imported from the module given by name.       Source:    So currently I have something like:  command = sys.argv[1] try:     command_module = __import__("myapp.commands.%s" % command, fromlist=["myapp.commands"]) except ImportError:     # Display error message  command_module.run()   This works just fine, I'm just wondering if there is possibly a more idiomatic way to accomplish what we are doing with this code.  Note that I specifically don't want to get in to using eggs or extension points. This is not an open-source project and I don't expect there to be "plugins". The point is to simplify the main application code and remove the need to modify it each time a new command module is added.


I noticed that my path environment variable had the path for my home's binaries $HOME/bin.   I did not add $HOME/bin directory to my path environment variable so how did $HOME/bin get added to the path?    RE - :  This question is specific to the environment variable "PATH" and is further specific to how does a specific value, i.e. $HOME/bin, get appended to the environment variable.  The "possible duplicate":   does NOT mention the environment variable PATH anywhere in the question or answer does NOT mention anything about $HOME/bin anywhere in the question or answer

I have a Linux instance that I set up some time ago.  When I fire it up and log in as root there are some environment variables that I set up but I can't remember or find where they came from.     I've checked ~/.bash_profile, /etc/.bash_rc, and all the startup scripts.  I've run find and grep to no avail.   I feel like I must be forgetting to look in some place obvious. Is there a trick for figuring this out?


I have a model from Source Filmmaker that has a bunch of different textures. It's all imported and ready to be textured using Blender nodes, but since there are so many objects (over 40) in this particular model, I figure it would be a waste of time to manually reshade/texture every single material which could take several hours. Instead, I could just write a simple script that could read the texture VMT files (from SFM) which define what each texture file is for (diffuse, bumpmap, etc.) in batch and create all the Blender shaders nodes automagically once the .blend file is there. The snag is .blend is a binary file, and I can't read it or edit it in a text editor. Is there any way at all to create Blender nodes programmatically (i.e. not inside the Blender GUI but perhaps importing other things or using addons?)

How can I define the different properties of an Cycles/Eevee material? Such things as glossy, glass, diffuse, RGB-color, emissive via python scripting?


I am very new to Number Theory, I understood the basic concepts and theorems but what I am struggling at is that I am not able to apply them on questions, and basically I am not able to process the problem in 'number theory' theorems rather I am thinking from an absolute manner. I have solved around 15-20 divisibility problems of Number Theory and I still have no idea how you deal with congruences in a real problem, for example: Prove that for positive integer $ n$ we have $169| 3^{3n+3}-26n-27$. My approach to this problem was by simplifying the expression as much as I can but it involved congruences, which didn't even strike me. Even when I am reading congruence questions' answers, I am not able to simply understand Now I have a number of questions:  first, does it take time to develop that 'intuition' while solving problems? second, can elementary number theory be mastered through sheer practice? third, is there a good resource to study and practice congruences?


In java script there is an alternative to if statement i mean like ternary operator  : (boolean expression )? option 1: option 2, it is elegant compact and sometimes less confusing. I have searched a lot to find an alternative for 'if' statement in python but i couldn't find anything. Is there any way to trick python so we can avoid if statement ?

If Python does not have a ternary conditional operator, is it possible to simulate one using other language constructs?


On my computer I have a typical SATA SSD (with my current Windows 10 installation) and and another separate M.2 SSD. I have more than enough space on my normal SSD and would like to install KUbuntu on my M.2 SSD. As I read through questions about dual booting, I see warnings about things like UEFI, Secure Boot, and Fast Startup and wonder if they apply to me since most of the time it seems as if they are all talking about dual booting from the same drive. I have the installer flashed to a USB drive right now but I would like to know if I should be worried about anything such as corrupting my Windows installation. I would like to know if I can keep fast startup on, if I have to change anything with UEFI or secure boot, and if I have to unplug anything like the people on this discussion are talking about;  Also feel free to give me some simple partition layouts geared towards programming for my KUbuntu  installation :)

I have recently got an Alienware M17x R4 and since it has two hard drive bays I was thinking of putting my hard drive from my old laptop and installing Ubuntu on it without making any changes to the drive that has Windows on it. Also if possible to add a entry to the Windows boot loader to boot Ubuntu instead of using GRUB.


This code was taken from another post at  where it was pointed out that there is an SQL injection vulnerability. What about this code is vulnerable, how could it be exploited, and how can it be made safe?  <?php  include("config.php");   function getAllVotes($id)  {      $votes = array();      $q = "SELECT * FROM entries WHERE id = $id";      $r = mysql_query($q);      if(mysql_num_rows($r)==1)//id found in the table      {          $row = mysql_fetch_assoc($r);          $votes[0] = $row['votes_up'];          $votes[1] = $row['votes_down'];      }      return $votes;  }   function getEffectiveVotes($id)  {          $votes = getAllVotes($id);          $effectiveVote = $votes[0] - $votes[1];    //ERROR THROWN HERE         return $effectiveVote;  }   $id = $_POST['id'];  $action = $_POST['action'];   //get the current votes  $cur_votes = getAllVotes($id);   //ok, now update the votes   if($action=='vote_up') //voting up  {       $votes_up = $cur_votes[0]+1;     //AND ERROR THROWN HERE       $q = "UPDATE threads SET votes_up = $votes_up WHERE id = $id";  }  elseif($action=='vote_down') {      $votes_down = $cur_votes[1]+1;      $q = "UPDATE threads SET votes_down = $votes_down WHERE id = $id";  }   $r = mysql_query($q);  if($r) {      $effectiveVote = getEffectiveVotes($id);      echo $effectiveVote." votes";  }  elseif(!$r) //voting failed  {      echo "Failed!";  }  ?>

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


So, I have field called name on my custom field and I am writing a before trigger insert trigger to copy the name of the other lookup field into the name field which is a standard required field and looks like I cannot remove the required on the field. Now, my trigger copies the name of the other field into the name field only if I write something before saving. If I don't fill the name and try to save the record I get the error 'The following field must be completed : name' . How do I solve this because I cannot ask users to fill some rubbish as the name and tell them not to worry cause once they save the field the contents of the other field get copied ? Which is not bright I suppose.  if(Trigger.isBefore){             //Process before insert that is to copy the name of the Template Id into the name of the checklist object             set<Id>CheckListTemplateId = new set<Id>();             for(CheckList__c c : Trigger.new){                 if(c.TemplateId__c != null){                     CheckListTemplateId.add(c.TemplateId__c);                   }                }             System.debug('The set value is :' + CheckListTemplateId);             if(!CheckListTemplateId.isEmpty()){                 Map<Id,CheckListTemplate__c> checkListTemplateObj = new Map<Id,CheckListTemplate__c>([Select Id, Name From CheckListTemplate__c Where Id IN: CheckListTemplateId]);                 for(CheckList__c c : Trigger.New){                     if(checkListTemplateObj.get(c.TemplateId__c).name != null){                         // Copy the value of Template name from CheckListTemplate__c into name in CheckList__c                         c.Name = checkListTemplateObj.get(c.TemplateId__c).name;                     }                     }             }                 }

I am trying to copy the value of user selected Status value into the standard salesforce required Company field. Now, when I try to save the record on the object since I am not entering any value in the Company field, the record is not being saved. How do I solve this kind of issue? Any leads appreciated  trigger CopyStatusToTitle on Lead (before insert, after insert) {      List<Lead> leadList = new List<Lead>();     if(Trigger.isInsert){         if(Trigger.isBefore){             //process before insert               for(Lead l : trigger.New){                 l.Company = l.Status;              }          }else if(Trigger.isAfter){             //process after insert          }       } }


I found a way to prove this using Chebychev's theorem, are there ways to solve it without relying on this?

If $n>1$ is an integer, then $\sum \limits_{k=1}^n \frac1k$ is not an integer.  If you know , then you know there must be a prime $p$ between $n/2$ and $n$, so $\frac 1p$ appears in the sum, but $\frac{1}{2p}$ does not. Aside from $\frac 1p$, every other term $\frac 1k$ has $k$ divisible only by primes smaller than $p$. We can combine all those terms to get $\sum_{k=1}^n\frac 1k = \frac 1p + \frac ab$, where $b$ is not divisible by $p$. If this were an integer, then (multiplying by $b$) $\frac bp +a$ would also be an integer, which it isn't since $b$ isn't divisible by $p$.  Does anybody know an elementary proof of this which doesn't rely on Bertrand's Postulate? For a while, I was convinced I'd seen one, but now I'm starting to suspect whatever argument I saw was wrong.


There’s something wrong with my Windows boot. But before I reinstall Windows 10, I need to backup my Minecraft saves with Linux.  So I use Linux live USB mount into Windows system disk, but I can’t find my .minecraft folder! The folder should be in Local/Users/Andare/AppData/Roaming. There’re many other folders. But I didn’t find .minecraft. And I tried to search .minecraft, but I got no results! Could the folder be hidden?

I wanted to add classpath to my JDK. While searching a way to do it I noticed everyone open .profile file using terminal. But when I want to open and edit it with a text editor I couldn't see that file in Home folder.  Can someone tell me why is this. And also if possible how can I access .profile in home folder the GUI way.


How to go about consolidating three stack exchange accounts?

I accidentally posted a question without being logged in. Is there a way to associate that question with my account?   For more information, visit "" in the .   a.k.a. How can you link a registered account to a cookie-based account? a.k.a. How do I merge an unregistered account with a registered account a.k.a. Merging users a.k.a. How do I associate anonymous questions I’ve asked with my registered account? a.k.a. Is there a way to claim an unregistered user? (in case anyone searches with those terms)


I know this question has been asked a million times before but I have checked out the previous posts and none of the advice given in them has worked for me. I'm getting this with the medibuntu repository.    I'm running Xubuntu 12.04 so I know it's not an EOL issue.  My internet connection is fine. I'm using it at the same time I'm doing the update. I'm able to surf the net, etc. I have a proxy but if that was the issue wouldn't all the repositories and PPAs be affected? Also, I've never had issues with the proxy server doing this before. This is the first time I have run across this error. I changed servers twice to different servers. I tried to select the best server and I tried the main server I tried the following three commands all without error sudo apt-get autoclean, sudo apt-get clean, and sudo apt-get autoremove. Then I tried running the update again and it still came up with the 404 error I ran sudo apt-get update | grep NO_PUBKEY and it just came up with the same error message   I don't know what else to do at this point.

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


In my project, I want to get all content of a SPListItem which is a calendar event. However, I have no idea to get them.   using (SPSite site = new SPSite(@"http://spabc/"))             using (SPWeb web = site.OpenWeb())             {                 SPList cal = web.Lists["Calendar"];                 SPListItemCollection items = cal.Items;                 string texts = string.Empty;                 foreach (SPListItem item in items)                 {                     var xml = item.Xml;                     texts += xml;                  }                 lab.Text = "Event: " + texts;// it shows "Event: "             }   Target:  Title, start Time, End Time, All Day Event, and Recurrence..  example of recurrence:     Recurrence: Every 1 month(s) on the first Tuesday

Is there a way to get the text displayed for the "Recurrence" field on the View Item screen for an OOB "Event" list item through the object model?  For example, I see:  "Every 1 month(s) on the first Tuesday"  Is there maybe a calculated field that I can reference using an SPListItem to get at this string (ensuring it's localized correctly)?  For example:  lblRecurrence.Text = item["RecurrenceText"].ToString();   Response targeted for SP2007, but interested if this carries over to 2010?  Or if there is a way to get at it in 2010 that wasn't there before?


I am facing a problem with JS object manipulation. I guess I know where is the problem but I cannot find a solution. I am trying to change the keys inside the objects from camel case to snake case (API requires snake case) by iterating over all of them inside the array. But when I change it, it makes a copy of it and does not affect the real object (console.log outside the loops). I hope it is clear, here is the code: for(user of allUsers) {                 for(key in user) {           key = changeCase.snakeCase(key)           console.log(key) //here it shows changed keys         }       }  console.log(allUsers) // no changes in keys here

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


I wrote a function in JavaScript, that replaces accents in a string to certain characters.      function textToURL(str) {     str = str.replace(/á/gi,'a');        str = str.replace(/é/gi,'e');        str = str.replace(/í/gi,'i');        str = str.replace(/ó/gi,'o');        str = str.replace(/ö/gi,'o');        str = str.replace(/ő/gi,'o');        str = str.replace(/ú/gi,'u');        str = str.replace(/ü/gi,'u');        str = str.replace(/ű/gi,'u');        str = str.replace(/ /gi,'-');        return str; }   I'm sure there's a more clean and more simple way to write this code with arrays, or Regex, but how?  Thanks in advance.

For a poor man's implementation of near-collation-correct sorting on the client side I need a JavaScript function that does efficient single character replacement in a string. Here is what I mean (note that this applies to German text, other languages sort differently):  native sorting gets it wrong: a b c o u z ä ö ü collation-correct would be:   a ä b c o ö u ü z  Basically, I need all occurrences of "ä" of a given string replaced with "a" (and so on). This way the result of native sorting would be very close to what a user would expect (or what a database would return). Other languages have facilities to do just that: , in , , . But what about JavaScript? Here is what I have right now. // s would be a rather short string (something like  // 200 characters at max, most of the time much less) function makeSortString(s) {   var translate = {     "ä": "a", "ö": "o", "ü": "u",     "Ä": "A", "Ö": "O", "Ü": "U"   // probably more to come   };   var translate_re = /[öäüÖÄÜ]/g;   return ( s.replace(translate_re, function(match) {      return translate[match];    }) ); }  For starters, I don't like the fact that the regex is rebuilt every time I call the function. I guess a closure can help in this regard, but I don't seem to get the hang of it for some reason. Can someone think of something more efficient?  Answers below fall in two categories:  String replacement functions of varying degrees of completeness and efficiency (what I was originally asking about) A  of  , which is now  among JS engines (not so much at the time of the question) and could solve this category of problem much more elegantly.


so I've successfully merged my 2/3 partitions into one and so now I have 2 partitions left, the one that I just merged cannot merge into my primary partition. It doesn't come up with the delete volume option in order for me to merge but only shrink volume. I've tried the Diskpart command prompt to try and force delete it but its jut kept on saying it was in use which it isn't. 32win7 is my primary and I just merged partition C and D together. thanks for the help  Primary Partition is 48gb and Logical/extended drive is 250

I am trying to delete my existing windows partition using disk management, when I am right clicked on the selected partition the 'Delete Volume' and 'Extend Volume' options are grayed out ( doesn't allow deletion and extension), and I can not also change or remove the drive letter of the disk which has above problem. And Another partition that I don't want to change anything it allows all the options. Why does this happen?


Currently I am having USB 2.0 port Laptop. I am in the plan to buy USB 3.0 Pendrive/External Hard Disk. Whether USB 3.0 pendrive/ext HDD will support USB 2.0 Laptop's port? Or it will have problem to use?  Thanks in advance.

I am planning to buy external hard drive that supports USB 3.0. Will it work with my old notebook that has USB 2.0?


I want to install Ubuntu on a usb stick and run the OS from it and also use the same usb as main drive, like everything i install it's kept on there so then I'm able to run like "my user" on another computer. It's possible?

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.


We know that Yang Mills Theory forms the basis of the Standard Model of Physics, which describe the interaction of elementary particles at high energies, of course not including gravity. Yang Mills theory (gauge theory) and gravity are described by local invariance. String theory unifies gauge theory and gravity, what is the relation between gauge theory and gravity?.

Currently, (classical) gravity (General Relativity) is NOT a gauge theory (at least in the sense of a Yang-Mills theory).   Why should "classical" gravity be some (non-trivial or "special" or extended) gauge theory? Should quantum gravity be a gauge theory?  Remark: There are some contradictory claims in the literature to this issue. To what extent gravity is "a gauge" theory?Obviously, GR is not a YM theory. So, why do some people say that gravity "IS" a gauge theory? I found this question relevant, e.g., then we handle GR in the Einstein-Cartan theory or any other theory beyond GR, like teleparallel theories or higher-derivative gravitational theories. So I think it could be useful to discuss the "gauge flavor" of gravity here.


When I'm busy, checking in to my flights via the web is often convenient. I get my boarding passes sent right to my phone and I don't need to worry about printing them before arriving to the airport. However, I also like collecting physical copies of my boarding passes. They're cool momentos of my travels more than anything else, and when I get the chance to print them out, I typically do.  My question is, if I've already checked into my flight on my phone, can I print another set of boarding passes at the airport? I do like the official airport paper ones most.  To make this question more general, consider the unfortunate situation of your phone dying. Having a backup physical copy of your boarding pass could save the day.   In essence, is there anything stopping me from making another boarding pass at the kiosk after I've checked in beforehand?

I'm flying to Tokyo. The flight was sold through Finnair. The first leg is operated by American Airlines. The second and final legs are operated by Finnair.  When I checked in online, it said that some airports on my journey (didn't say which one) don't allow mobile boarding passes?? Meaning I will need a physical copy.  Unfortunately I don't have easy access to a printer. Will I still be able to print all my boarding passes at the airport even though I already checked in online?


I am using 12.10. I am able to get my terminal with [super] + [w] keys but not with alt + tab keys. why is it invisible after minimizing the terminal. how can i correct it ?

I minimized my terminal after doing a repo sync.  I cant find it on any desktop now! Please help.


I purchased an iPhone 6s second hand and the person whom I purchased is now in London. (I am in India)  When I restart the phone, it says this iPhone is currently linked to an appleID.  When I asked the person what's the appleID of the phone, he says that it doesn't have any but the phone shows something like this :    What do I do ?  How do I get my phone to work ?  Anyone please help I also tried putting the phone in DFU mode (press home button + lock button) and then installed the ipsw through itunes, still the above screen appeared.  What can I do ?

I bought a used iPhone 4.  The previous owner re-set the phone, but did not remove the device from their iCloud.  It is asking me for their iCloud information when I try to set-up the phone.  I don't have contact with the previous owner anymore.  Is there a way to remove the device from their iCloud so I can use a new one?


import numpy as np     a = np.arange(6).reshape(2,3) np.meshgrid(*[np.arange(x) for x in a.shape])   What is the role of the asterisk before the parameter?    why does it works? what dose it mean adding an asterisk before list comprehension as a parameter?

In the following method definitions, what does the * and ** do for param2?  def foo(param1, *param2): def bar(param1, **param2):


How can I find out who the originator of the email was or their location? I received a personal offensive email and I want to track who it came from?

How can I know where an email really originated from? Is there any way to find it out?     I have heard about email headers, but I don't know where can I see email headers, for example in Gmail. Any help?


I'm using iOS 5.1.1 (9B206). I want to upgrade my iPhone to iOS 6.1.3, but I don't know how to do this. I have tried downloading the IPSW of iOS 6.1.3 to upgrade, but it doesn't make any changes. The second time, I try building file SHSH with IPSW, but that didn't work either. Any ideas for this problem to upgrade from 5.1.1 (9B206) to ios 6.1.3 ?

I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this?


My question is simple.  In the classical mechanics, we know the least action principle does the variation on the action $$ S = \int (T-V) dt , $$ where $T$ is the kinetic term and $V$ is the potential term, to give the classical equations of motion.  So why the least action principle extremizes (minimizes or maxmizes) this quantity $$T-V = H- 2V = E-2V =2 T- H = 2T-E?$$ Here I also denote $H$ as Hamiltonian. And $E$ as the energy of the system. In this regard, the $E$ is conserved, but not extremized. But $$E-2V =2T-E$$ is extremized!  For example, if we write down the $(T-V)$ for a free falling object under constant gravitational acceleration $g$, we have $$T-V = \frac{1}{2} m \dot{y}^2 - m g y = E -2 m g y =  m \dot{y}^2 -E$$ with $E=\frac{1}{2} m \dot{y}^2 + m g y$ is conserved.    What is the physical significance of this $T-V$? (Provide good physical or math reasons.) I know how to derive equations of motion. I am asking a transparent way to understand why $T-V$ is in extremization. I suppose the extremization may minimizes or maximizes the action. (Not necessarily minimization, correct?) Do we have both examples of  The equations of motion minimize the action?  The equations of motion maximize the action?

Hamilton's principle states that a dynamic system always follows a path such that its action integral is stationary (that is, maximum or minimum).  Why should the action integral be stationary? On what basis did Hamilton state this principle?


I am new to latex. I am trying to add bibliography using .bib file. I have tried using \cite{} command to add the citation. But when I compile it it is showing question marks. Can someone tell me how can I add a citation in latex. I have used the following commands: \bibliography{references}  \bibliographystyle{ieeetr}  references.bib is the name of the .bib file

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


I have problems when using XMLHttpRequest. One occurs in Chrome; the other in firefox  xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function() {     if (this.readyState == 4) {         if (this.status == 200)              elmnt.innerHTML = this.responseText;         }         if (this.status == 404) {             elmnt.innerHTML = "Page not found.";         }     } } xhttp.open("GET", file, true); xhttp.send();   I'm working locally, i.e. all protocols are file://  In chrome, where I have added parameter --allow-file-access-from-files, this.status is 0. Why?  In firefox, the status is 200, but there will be a XML parsing error when the included file has code like this:  <script> alert(-1<1); </script>   and an XML parsing syntax error occurred indicating 10th character.  Why? I guess firefox does not recognize '<' between script.  Are they bugs or some issues I don't know yet?

Are CDATA tags ever necessary in script tags and if so when?  In other words, when and where is this:  <script type="text/javascript"> //<![CDATA[ ...code... //]]> </script>   preferable to this:  <script type="text/javascript"> ...code... </script>


I am using macOS High Sierra V10.13.6. I can set up my custom environment variables in .bash_profile. But where is the system default environment variables are stored in the mac system  For Ex:  If i type echo $HOME in terminal i get the output as /Users/parithibang  Where is this $HOME variable is been set up in the Mac Machine?  In which path this is been set?

We used to use /etc/environment to set system-wide environment variables on Mountain Lion. However, it seems this file is no longer read. Ideally the solution should apply to all users, and we need it to work with ssh console sessions. So we need this to work ssh user@mavericks-machine 'echo $MY_ENV_VAR'  So far we've tried:  /etc/launchd.conf Works for all users, but only applies to 'windowed' applications, i.e. works in Terminal, but not in an ssh session.  ~/.profile, ~/.bash_profile etc. Only applies to shells   Any suggestions?


I am an Indian citizen going to the UK in June on visitor visa, multiple entry valid until October. On my return journey, I have a layover of 12 hours and 15 minutes, and I also have to change planes from KLM to Jet Airways. Do I need a transit visa? Is there any option that I can get visa for 12 hours (short stay visa or transit visa) at the Amsterdam airport itself?

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


The panel that appears as shown in the image below, cannot be re-opened. It only appears, on the left-hand-side of the screen when I create a new object. How do I get it back as shown in the image?     My "Data" tab, looks different.

When you first add a cylinder, you have the option to change the number of vertices, etc, but once you do anything else in blender, it seems you no longer can edit those parameters.   Is there a setting anywhere or an add-on that allows these parameters to be edited later on? If not, how easy would such an addon/feature be to create for anyone reading this?


i need an overloaded method that uses enhanced for loops to build and return a String that contains the elements in an array. This is my work:   public static String arrayToString(double[] dblArray) {     String str = "";     for (double i : dblArray) {         System.out.println(dblArray.toString());     }     return str;   }   And i got output something like this:   [D@232204a1  [D@232204a1  [D@232204a1  [D@232204a1   I think this is adress of array's elements.

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


I have a Dell Inspiron 15 (5000 series) and am trying to dual-boot Windows 10 (already installed) and Ubuntu 16.04.3 LTS. I have a bootable USB stick, which I made using the ISO file from Ubuntu's website, and UNetBootIn (I have also tried this with a stick made from Rufus). However, when I try to boot from the USB to install Ubuntu, I am unable to do so.  I have tried booting from a USB drive on Legacy BIOS, which does start booting up Ubuntu, but it freezes a few seconds into the boot process. I have also tried booting on the standard UEFI, but adding grub (specifically, EFI/grubx64.efi on my USB stick) as a boot option. Note that when I do this, I disable Secure Boot. This does bring me to the standard grub screen, and I can click "Try Ubuntu without Installing", but it freezes on the load screen.  Any advice would be greatly appreciated! :) Thanks in advance!

This is the third time I've tried to install Ubuntu Server 14.04.03 64-bit on the same laptop, and each time it caused different problems.  Each time I wrote the same iso image to a USB flash drive by using a different application and OS.   Universal USB Installer (pendrivelinux.com) from Windows WinImage writer from Windows built-in image writer from Linux Mint 17.2    The iso image is the same in all three cases, the USB flash drive is the same, and the laptop is the same. However each time the installation of Ubuntu gave me different installation options. For example, the last time I installed Ubuntu, it didn't show all the packages to choose while installing (Basic Ubuntu server, etc.).


The spell Melf's Acid Arrow does 4d4 on hit and 2d4 next turn (I'm ignoring what happens for a miss). If you roll a 20 for your spell attack roll, you double the 4d4 to 8d4.   What about the 2d4 next turn? Does that get doubled too or does that just stay at 2d4 because it occurs on the next turn?  I know that  covers additional kinds of damage during a critical hit, but this is the same substance that did critical damage, continuing its damage in a later round.

I'm a bit confused on how extra damage works for critical hits. Let's take the following example: A thief with sneak attack rolls a crit. I'm under the impression he rolls double his normal attack damage dice AND double his Sneak Attack damage dice. Is this accurate? Another example, I finished DM-ing my first campaign recently. The Giant Spider enemy monster has an melee attack that causes a constitution saving throw. If the player fails, the enemy rolls an additional 2D8 of damage. In this situation, if there was a critical hit, and the player failed their saving throw, would I also roll double dice on the additional damage? Or is that considered a separate attack?


I have an external hard disk drive that I have set to drive F which contains some programs that I have shortcuts on the desktop to. I have a second external hard disk drive which I store my music on which is auto assigned to drive E, due to someone thinking that Australians love to have wings on power plugs for hard drives while power boards have each socket close together. I can have both of these hard drives set at the same time.  My music hard drive I normally only plug in when I synchronise music to my iPod, but on occasion when I unplug my music hard drive and plug my old one back in or at times when I turn on my computer with the music hard disk drive in, turn off my computer and turn it back on with my old hard drive, its drive letter gets switched to E.  I get annoyed having to always go into disk management and change the drive letter back to F when this happens so   Can I lock my hard drive to always be F? If anything else tries to be F, it can fail for all I care. Is there a batch file I can use that'll go though all the steps of Disk Management to change a drive's letter, that way I can set it up in the startup folder?   EDIT:      I get annoyed having to always go into disk management and change the drive letter back to F when this happens   I am just pointing it out in case someone missed it, because I already use Disk Management to change the drive letter back to F. If it stayed there then I would have a problem.

I have scripts that expect specific drive letters for hard drives. Windows sometimes assigns the different drive letters (e.g. I expected my Maxtor drive to be E:, but it's now F:, therefore my scripts will fail), depending on the order of how the drives are plugged into my laptop.  In Windows 7, how do I assign a permanent drive letter to a drive?


There are so many things wrong with LaTeX2e according to the latest discussion, , from documentation to speed, inflexible kernel, etc. We are perhaps waiting in vain for LaTeX3 and expl3 full deployment but what is called "gentle re-fractory" see . What are the deficiency and features in LaTeX2e that LaTeX3 project hence "gentle refractory" and L3 programming seeks to provide solution to (and how significant )?  Surely separating design and codes will be great, but LaTeX3 project must prove it's relevance in terms of quality of extension, alternate solutions, user interface and better features than LaTeX2e! Secondly, I haven't seen any basic and compilable Tex for mobiles OS like android. Many use online Tex Editors and tools or snippets  like Overleaf. Will need latest implementation of TeX on say android OS and MacOS. In my opinion, LaTeX3 project has taken so much time, (more than 20years since the project started), and surlely new issues of change due to time will continually postpone "getting perfected for release" Sure, it won't be able to replace LaTeX2e and conTeXt but "soft refractory" for possible modernization I find information on the following discussions partly useful and educating..    .  .   Am currently working on mobile implementation of TeX-Latex.

There are a few questions on this forum asking about why Latex3 is taking so long to come out. However, all of these are from the early 2010s. I'm just wondering what the current state of the project is and whether it's ready (or nearly ready) for prime time?