Evaluate the following the limit: $$\lim_{x\to\infty}\left[x - \sqrt[n]{(x - a_1)(x - a_2)\ldots(x - a_n)}\right]$$  I tried expressing the limit in the form $f(x)g(x)\left[\frac{1}{f(x)} - \frac{1}{g(x)}\right]$ but it did not help.

I think it is zero; $$\lim_{n \rightarrow +\infty } \left(\sqrt[m]{\prod_{i=1}^{m}(n+{a}_{i})}-n\right)$$ we can make that steps: $$\lim_{n \rightarrow +\infty } \left(\sqrt[m]{{n}^{m}\prod_{i=1}^{m}\left(1+\frac{a_i}n\right)}-n\right)$$ and then: $$\lim_{n \rightarrow +\infty } \left(n \cdot \sqrt[m]{\prod_{i=1}^{m}\left(1+\frac{{a}_{i}}{n}\right)}-n\right)$$ each bracket aspires to unit so we have:  $$\lim_{n\rightarrow \infty} (n-n)$$ and..  $$\lim_{n\rightarrow \infty} (0) = 0$$


Any other crop   Any other crops  Would you tell me what is the difference between these?

While I was answering a question on ELL, I got confused with a  from a fellow user. After I indicated that:     "Do you have any idea to prove it?'   is grammatically correct, the OP commented that "ideas" should be used in place of "idea".  The comment befuddled me. I thought until now that "any" should be followed by singular noun and not plural. So I searched Google and saw it's a huge debate going on and there is no end to it. I got no perfect and trustworthy source. So I thought to post the question here.  So what is the right rule? Should singular or plural be used after "any"?


Okay, so looking at the basic definition of energy the force is summed over the distance it is applied. Why exactly is it taken over the distance applied and not the time applied? I understand that the impulse and hence the change in momentum is what we call this summation over time, but it's not exactly clear to me why we chose to do it the way we did.   Side note - I've seen the examples where there's an object at rest and if you took the force over time you would get infinite energy, but if you took the sum of the force (both holding it up and pushing it down (gravity) you would get 0, and thus an integral over the net force would be 0, right? Thanks   -edit  Okay, so really the crux of what I'm getting at that I can't seem to find an answer for is: Why did we choose to do it this way? What experiment or thought experiment led us to believe that momentum isn't in fact energy, but a separate quantity? The problem I keep having is that when you want to sum up this quantity we know as force, you have two options, sum it over the time its applied or the distance. I just don't understand the idea behind choosing one over the other.

So the formula for work is$$ \left[\text{work}\right] ~=~ \left[\text{force}\right]  \, \times \, \left[\text{distance}\right] \,. $$  I'm trying to get an understanding of how this represents energy.  If I'm in a vacuum, and I push a block with a force of $1 \, \mathrm{N},$ it will move forwards infinitely. So as long as I wait long enough, the distance will keep increasing. This seems to imply that the longer I wait, the more work (energy) has been applied to the block.  I must be missing something, but I can't really pinpoint what it is.  It only really seems to make sense when I think of the opposite scenario: when slowing down a block that is (initially) going at a constant speed.


I'm trying to install Ubuntu 14.04.1-desktop-i386 on a 32-bit Thinkpad T400 with Windows 7 on it. I have tried installing Ubuntu by mounting the ISO from a DVD+R I burned, a USB drive, and my downloads folder. I mount the ISO with Virtual Clone Drive. I downloaded the ISO from the Ubuntu website. When I try to install by rebooting the computer, I get sent straight to Windows 7, as if a regular restart just occurred. When choosing the "Help me boot from CD" option, I am asked to install CD boot helper. Unfortunately, an error comes up that says:  Cannot install into C:/ubuntu.  There is another file or directory with this name.  Please remove it before continuing.  For more information, please see the log file:  c:/users/admin/appdata/local/temp/wubi-14.04-rev286.log  I am not sure what to do. I deleted the wubi-related files I could identify in the folder, and it still does not work. Please help.  EDIT: I want to remove Windows 7 from my computer, and Ubuntu is not installed at all on my computer. Just in case I wasn't clear

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


I wanted to make simple Notepad program that can be used with password, I mean that it can only run if correct password is typed. However, it looks like it appends some trailing spaces! Here are some screenshots:   Here's my code: File passFile = new File(System.getProperty("user.dir")+"\\jdata\\password.txt");                 if (passFile.exists()) {                     if (passFile.length() != 0) {                         String password = JOptionPane.showInputDialog(window, "Enter password or Click 'Cancel' to quit:", "Password", JOptionPane.QUESTION_MESSAGE);                         password = password.replaceAll(System.getProperty("line.separator"), "");                         try {                             Scanner scan = new Scanner(passFile);                             String correct = scan.nextLine();                             if (password != correct) {                                 System.out.println(password);                                 System.exit(0);                             }                             scan.close();                         } catch (Exception e7) {                             if (e7.getClass().getCanonicalName() != "java.util.NoSuchElementException") {                                 System.exit(-1);                             }                         }                     }                 }  Any ideas?

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


Two mutual funds I follow both plummeted on the same day that they paid out their annual dividends and capital gain distributions. (The rest of the year was relatively stable.) The timing seems too coincidental -- is there a standard/natural reason why this sort of drop might happen on "dividend day"?  The funds are FLVCX (dropped 27% on 2016-12-02) and NBSSX (dropped 9% on 2016-12-16).   Note that a sudden price drop on "dividend day" can be good for investors if they are reinvesting dividends: the lower the share price on that day, the larger number of shares they receive.

I have no prior experience with stocks so please forgive me if this is a dumb question but I don't even know what to try googling. Two days ago I signed up with scottrade. I put $1000 into ICENX mutual fund. It got me ~56 shares. Today I log in and I see this:    What has happened? Apparently the share price took a huge plunge but my shares magically multiplied? Why does it say I lost $258 if I actually gained $12? Thank you guys so much!


In the M.M. (Monster Manual), it says that PC (Player Characters) can become vampires. I'm not good at all with mythology, so I'm asking for a little help here.  How can a PC get turned into a vampire?

A PC in our group was off on his own following a recurring villain of our groups. He was paralyzed where he could move, and the vampire bit his neck. The vampire said "now you get to remain 19 (years old) forever" before he left the cave. This was all done in RP.  We found him later, and healed up his bite marks. Our characters know of vampires, specifically only the one that bit him (recurring villain), but don't really know how vampirism works, because it isn't a super common thing in this world yet.   My question as the player is:  How does RAW vampirism work in 5e?  Is it a disease that develops over time? Is it something where they have to die and be brought back as a vampire?


The Back button on the Android app doesn't behave as expected.  If I'm scrolling through the questions list on Stack Overflow, then I apply a filter say, for  questions, and then I open one of these questions and read through it and then I want to exit back to the list, pressing the Back button doesn't take me back to the filtered list where I was before.  Instead, it opens back the list of available tags to choose from, and then I have to scroll through the whole list of questions again to find where I was, and that's not as convenient as it could be.

This looks a little bit like a variation on  but specific to the tags view.  Reproduction (app version 1.0.71):   Select any site (say Meta) from the sidebar Switch to the tags view using the top bar Choose a tag, any tag ( is nice)   optionaly refine your search with more terms  Go to any question found, go back   you end on the unfiltered tags view  Go back again   lucky you, your search is here


If there is a fire in a building and I am on 10th floor and I can't exit the building.Is it safe to jump out of the window with a chair and when chair is close to the ground I just jump of the chair and I will be safe. Is this safe or not? Would I live or not

Imagine you're trapped inside a free falling elevator. Would you decrease your impact impulse by jumping during the fall? When?


Whenever I "double click" on an Excel file and another Excel file is open, the newly opened file automatically opens in the same application window as the previously opened Excel file. This isn't limited to just Excel, as I've seen Word do this as well. This poses a problem when wanting to compare documents side by side.    The current solution I have for this is to actually open another Excel or Word instance, and then open the file from within that application window itself. Is there a way to force Office to open a new instance of the application when double clicking on the file icons?  I'm currently using Office 2007 and Windows XP, but I've seen this on Office 2010 and Windows Vista and 7. I'm looking for an overall solution if possible.

When I have Excel running and I double click an Excel file in Windows explorer, I'd like it to launch in a new window by default so that I can move documents to separate monitors. Is there any way to get this behavior?


I have around 1 Lakh+ (100,000+) point features in my shapefile, which has some duplicate records in it. I had found the duplicate records present in the attribute table and print those in python console. But i want to select those duplicate features in attribute table so that i can delete those entries from attribute table. How should this can be done using python? I had attached my snippet for printing the duplicate records present.  from collections import Counter layer = iface.activeLayer() idx = layer.fieldNameIndex('name') attributeList = [feature.attributes()[idx] for feature in layer.getFeatures()] print([attribute for attribute, count in Counter(attributeList).items() if count > 1])

I am trying to calculate a field that marks duplicates and sequentially numbers them.  I am using the code below that I found here: .  It works, but I get a duplicate starting value before it begins sequentially numbering unless I only run the field calculator on the selected values.  When I calculate after manually selecting the duplicate rows and running it on only those values, it works fine.  Here's the code:  prevFieldValue = '' counter = 0 def GetDuplicateCounter(myFieldValue):   global prevFieldValue   global counter   if myFieldValue == prevFieldValue:     counter += 1   else:     counter = 1     prevFieldValue = myFieldValue   return counter   Results running it on all roads (nothing selected):    Results running it after manually selecting the duplicated fields (not too efficient!).


Is there a word for when two people really like each other, but aren't dating, don't want serious relationship?   EDIT  No, they aren't involved at all. They do not engage sexually with each other.

I'm looking for a word to describe that a particular situation where two people (a man and a woman) are probably the best of friends but have no romantic inclinations towards each other. They may invade each others thoughts periodically but aren't really in a relationship per se. What would be a good word to describe this?  I'm aware of "platonic" but am wondering if there is another word?


Hi so yesterday I was trying to update my wifi drivers but when I rebooted, the option to "Enable wi-fi" disappeared on my toolbar? How do I make it show up again?  I have Qualcomm Atheros QC6174a btw.  Thanks.

How do I install my wifi drivers? There is no option to "Enable Wi-fi" on my toolbar except for "Enable Networking".  Any help would be appreciated,.  Thanks.


I have a 32-bit very old pc, I tried with the 32-bit option that was in the official page don't worked to me,my pc dosen't have cd, I need the USB installation someone know how to install ubuntu in this 10 years old PC. Thank You

Why is there no 32 bit ISO for the new Ubuntu 18.04?


A DNA molecule can be represented as a string of symbols $A, C, G$ and $T$, such as $GGATAATTCTAG\ldots GACCGTACCC$.   For the purposes of this question, we will assume that all DNA molecules contain the same (large!) number $N$ of symbols. Thus, a DNA molecule is an $N$-tuple $x = (x_1,\ldots , x_N)$ where $x_i\in\{A,C,G,T\}$ for each $i$.  Define the distance between two DNA molecules $x, y$ as the number of elements $i$ in ${1, \ldots ,N}$ such that $x_i\neq y_i$.   Prove that this defines a metric on the set of DNA molecules.  Tutor defined a set $S(x,y)=\{1,3,6\}$. Why is this? The rest of the working after that is fine.

A DNA molecule can be represented as a string of symbols $A$, $C$, $G$ and $T$, such as  $$GGATAATTCTAG. . .GACCGTACCC$$ For the purposes of this question, we will assume that all DNA molecules contain the same (large!) number $N$ of symbols. Thus, a DNA molecule is an $N$-tuple $x = (x_1, . . . , x_N)$ where $x_i  ∈ \{A,C,G,T\}$ for each $i$.  Define the distance between two DNA molecules $x$, $y$ as the number of elements $i ∈ {1, . . . ,N}$ such that $x_i \neq y_i$. Prove that this defines a metric on the set of DNA molecules.


While browsing through the tags on Chess Stack Exchange, I found something remarkable on :    That's not the complete excerpt for that , which reads     An opening variation where the opponent is tempted to make a bad move.   The first line is simply not shown. This is not a CSS/design issue, the first line simply isn't included in the HTML.  The same thing happens a few pages later:

With the tag page changed, there are some.. let's call them "controversial" opinions whether it's an improvement or not; I'd rather not comment on that, but point out a certain "feature" in the tag excerpts wikis which are shown on the \tags page:  Case in point from the TeX-SE tags page:      The  tag wiki excerpt reads:     TeX and friends give you the resources to put text in the header and footer of your document. This tag is for questions relating to this.   Huh?   I thought it was just someone was being lazy not providing a proper tag description. But it turned out that this happens on a lot more tags, to a different degree. The layout script, or whatever it is, tries to be clever, and removes some stuff in front of the tag excerpts to avoid repetition, presumably.   The cases I noticed so far:   "Questions tagged with [foo]" "This tag is about" "Choose this tag if your question is" "Use the [foo] tag for" "[foo] is" "This tag"   .. and probably more, I'm too lazy to search.   The point is -- the script tries to be clever and removes whole sentences, leaving weird and incomplete description, which is what tag wikis are all about.   Now, the questions:   Is this  or a bug? How exactly does it work? What template for tag excerpts should we use to avoid ridiculous entries like the one shown?


How do I write a mathematical equation for ARIMA(1,0,0)(1,1,0)[12] and How to substitute values of coefficients in that formula. My model is   ARIMA(1,0,0)(1,1,0)[12] ## ARIMA(1,0,0)(1,1,0)[12]  ##  ## Coefficients: ##          ar1     sar1 ##       0.6606  -0.5763 ## s.e.  0.1143   0.1295

I need help writing a SARIMA model I have obtained mathematically. My model is   ARIMA(1,0,4)(2,0,2) period 12.   I understand what the different parts actually mean but get very lost trying to write out the mathematical model. I have tried to follow other examples but as the models differ it makes it hard to apply it to what I have.


When I'm checking for some process, I usually write  ps aux | grep myprocess   And sometimes I get the output of   eimantas 11998  0.0  0.0   8816   740 pts/0    S+   07:45   0:00 grep myprocess   if the process is not running.  Now I really wonder why grep is in the list of processes if it filters out the output of the ps command after ps has run?

I've never really thought about how the shell actually executes piped commands. I've always been told that the "stdout of one program gets piped into the stdin of another," as a way of thinking about pipes. So naturally, I thought that in the case of say, A | B, A would run first, then B gets the stdout of A, and uses the stdout of A as its input.    But I've noticed that when people search for a particular process in ps, they'd include grep -v "grep" at the end of the command to make sure that grep doesn't appear in the final output. This means that in the command ps aux | grep "bash" | grep -v "grep" it is implied that ps knew that grep was running and therefore is in the output of ps. But if ps finishes running before its output gets piped to grep, how did it know that grep was running?   flamingtoast@FTOAST-UBUNTU: ~$ ps | grep ".*" PID TTY          TIME CMD 3773 pts/0    00:00:00 bash 3784 pts/0    00:00:00 ps 3785 pts/0    00:00:00 grep


To make certain actions simpler I'd like to know if it's possible to extend the node class in a way that allows you to add functions to the node class. What I mean is, I want to be able to perform actions like   $node->test();   or  $node->styledImage('field_name','style');   I was attempting to create it in a custom module like so  <?php  use Drupal\node\Entity\Node as BaseNode;  class AbleNode extends BaseNode {     public function test(){         return 'test';     } }   but then it dawned on me that this probably would only create a new type of entity that could give me those functions. It wouldn't actually let me perform these actions are preexisting nodes. Is adding functions to the node class possible, or even practical?

In Drupal 8 you can load an entity with:  $node = \Drupal::entityManager()->getStorage('node')->load(123);   This looks for the entity definitions and finds that node is defined by Drupal\node\Entity\Node - so (I guess) Drupal\node\NodeStorage will instantiate a new Drupal\node\Entity\Node instance.  What I'd like to achieve is subclassing Drupal\node\Entity\Node and being able to instantiate this subclass when it's appropriate. For example if I have a node bundle article, there would be a class:  namespace Drupal\my_module\Entity\Article; class Article extends Drupal\node\Entity\Node { }   And I'd call:  $node = \Drupal::entityManager()->getStorage('node_article')->load(123);   And the return would be my Article subclass.  I can achieve this by creating a new entity type and wiring it back to another existing entity definitions, for example the node-article example would be this class:  namespace Drupal\my_module\Entity; use Drupal\node\Entity\Node; /**  * @ContentEntityType(  *   id = "node_article",  *   label = @Translation("Content"),  *   bundle_label = @Translation("Content type"),  *   handlers = {  *     "storage" = "Drupal\node\NodeStorage",  *     "storage_schema" = "Drupal\node\NodeStorageSchema",  *     "view_builder" = "Drupal\node\NodeViewBuilder",  *     "access" = "Drupal\node\NodeAccessControlHandler",  *     "views_data" = "Drupal\node\NodeViewsData",  *     "form" = {  *       "default" = "Drupal\node\NodeForm",  *       "delete" = "Drupal\node\Form\NodeDeleteForm",  *       "edit" = "Drupal\node\NodeForm"  *     },  *     "route_provider" = {  *       "html" = "Drupal\node\Entity\NodeRouteProvider",  *     },  *     "list_builder" = "Drupal\node\NodeListBuilder",  *     "translation" = "Drupal\node\NodeTranslationHandler"  *   },  *   base_table = "node",  *   data_table = "node_field_data",  *   revision_table = "node_revision",  *   revision_data_table = "node_field_revision",  *   translatable = TRUE,  *   list_cache_contexts = { "user.node_grants:view" },  *   entity_keys = {  *     "id" = "nid",  *     "revision" = "vid",  *     "bundle" = "type",  *     "label" = "title",  *     "langcode" = "langcode",  *     "uuid" = "uuid",  *     "status" = "status",  *     "uid" = "uid",  *   },  *   bundle_entity_type = "node_type",  *   field_ui_base_route = "entity.node_type.edit_form",  *   common_reference_target = TRUE,  *   permission_granularity = "bundle",  *   links = {  *     "canonical" = "/node/{node}",  *     "delete-form" = "/node/{node}/delete",  *     "edit-form" = "/node/{node}/edit",  *     "version-history" = "/node/{node}/revisions",  *     "revision" = "/node/{node}/revisions/{node_revision}/view",  *   }  * )  */ class Article extends Node { }  // Results my Article sub type. $node = \Drupal::entityManager()->getStorage('node_article')->load(123);   This works fine (as much as I can see); however, it smells. It adds a new entity type, which is not true, and might cause other troubles in the future.  How do I define a subclass for an entity bundle so that loading the entity would return an object of that class?


I installed Ubuntu on a machine with Windows 8.1. And I think I screwed up big time while trying to figure out how to make the system a dual-booting one (the Ubuntu installer didn't detect that a Windows operating system was present on the computer. I assume it had to do with the way my USB-bootable drive was originally configured, but I'm not sure though). So, I believe I have installed Ubuntu over the Windows and the Windows, I think, has pretty much been wiped out. There were two partitions there: C, with the Windows itself and another one, D, with all my data.  Here are my questions:   Do you think I have permanently lost all my data that was stored on disk D? If not, is there any possibility that the data could be recovered?

I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.


I try to use my username Tootyfruity and it keeps saying invalid name even though it has online status lit up. any suggestions in how to end this error??

I am having trouble getting onto a server in Minecraft PE on iOS. When I tap on the person's server it just says invalid name:    I have tried turning off and restarting the iPad, going to home screen and logging back into the server but I have had no luck and no change. Is there a reason why this is so?


What is the right 'selector' to use to make 'My Button' work? I've searched this site, none seems to work for me?  <!DOCTYPE HTML>   <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="robots" content="index, all" /> <title>Example</title>

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


I am trying to make a villager that cannot be hit and has a custom name. How to I combine the tags {Invulnerable:1} and {CustomName:"\"BlaBla\""} into something that works? I'm using 1.14.4.

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


I am new to C# and am creating a test app to populate a combo-box from a table within an Access database.  I want to be able to set this information on the fly.  As a tester, I have created a new form, added a single combo-box called "TBCallOutcome", and added the code.  However, it seems to populate the drop-down with "System.Data.DataRowView" in every row.  Any ideas - thank you?      private void Form1_Load(object sender, EventArgs e)     {         string query = "SELECT [Call outcome] FROM [DD Call Outcomes] WHERE ((([Show on list])=True)) ORDER BY [Sort order]";         OleDbDataAdapter dAdapter = new OleDbDataAdapter(query, @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source='N:\\Test\\Dropdowns.mdb';User Id=admin; Password=;");         DataTable source = new DataTable();         dAdapter.Fill(source);         TBCallOutcome.DataSource = source;     }

I'm used to work with Java where large amounts of examples are available. For various reasons I had to switch to C# and trying to do the following in SharpDevelop:  // Form has a menu containing a combobox added via SharpDevelop's GUI  // --- Variables languages = new string[2]; languages[0] = "English"; languages[1] = "German"; DataSet myDataSet = new DataSet();  // --- Preparation DataTable lTable = new DataTable("Lang"); DataColumn lName = new DataColumn("Language", typeof(string)); lTable.Columns.Add( lName ); for( int i=0; i<languages.Length; i++ ) {     DataRow lLang = lTable.NewRow();     lLang["Language"] = languages[i];     lTable.Rows.Add(lLang); } myDataSet.Tables.Add(lTable);  // --- Handling the combobox mnuActionLanguage.ComboBox.DataSource = myDataSet.Tables["Lang"].DefaultView; mnuActionLanguage.ComboBox.DisplayMember = "Language";   One would assume to see some values in the dropdown, but it's empty. Please tell me what I'm doing wrong ;(  EDIT: mnuActionLanguage.ComboBox.DataBind() is what I also found on the net, but it doesn't work in my case.  SOLUTION  mnuActionLanguage.ComboBox.BindingContext = this.BindingContext;   at the end solved the problem!


Is there any bijection from $[0,1]^3$ to $[0,1]$? How can I construct it?

Could any one give an example of a bijective map from $\mathbb{R}^3\rightarrow \mathbb{R}$?  Thank you.


as a student of final yr i want to make a tablet of simple specification but i m not getting how to install any OS in it, I read about Ubuntu OS for tab, can i really install and Ubuntu on tab and if yes HOW??? please answer..

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


I've already tried to ask this question (), but people seems to misunderstand what I was trying to express, so I decided to ask it again.  My question is, if one writes $\mathrm{d}x^2$ (which is kind of a differential expression), should it be read as $$(\mathrm{d}x)^2$$ (differential of x, but squared) or $$\mathrm{d}(x^2)$$ (differential of $x^2$)?  The question can also be asked in a different way: if I want to express $(\mathrm{d}x)^2$, do I have to explicitly write the parentheses or just write $\mathrm{d}x^2$?  Keep in mind that I'm not asking about the meaning of the differential, but instead the notation related to it.

When we write $dx^2$, do we actually mean $$d(x^2)$$ (the change in respect to $x^2$), or $$(dx)^2$$ ($dx$ squared)?


I am not able to find the "my drafts" section on a Stack Exchange site.  Where is it?

In GMAIL you can list all your boss-tell-off and wife-cuss-out emails by clicking Drafts    I'd like to see my started-but-never-finished responses, possibly between x Answers and y Votes in /<<user>>/Stats/?


Found an old solution, but it doesn't work anymore:   This also doesn't work and only works on older OS:

I have a webpage that will display notifications to OS X's notification (system notifications).  But it will disappear in 10 to 15 seconds.  Is there a way to change how long it stays?  (and what about change to not disappear at all?)  I found several pages dated 2014, which suggested using  defaults write com.apple.notificationcenterui bannerTime 60   or use 3 instead to make it 3 seconds. But this method doesn't work for my Mavericks and El Capitan OS X.


How do I fix this major issue:  E: Type 'sudo' is not known on line 3 in source list /etc/apt/sources.list.d/libdvdcss.list   What do I do to fix this?  This is what I get when I open Synaptic Package Manager:  E: Type 'sudo' is not known on line 1 in source list /etc/apt/sources.list.d/libdvdcss.list E: The list of sources could not be read. Go to the repository dialog to correct the problem. E: _cache->open() failed, please report.   These are the file's contents:  sudo tee -a /etc/apt/sources.list.d/libdvdcss.list sudo apt-key add - sudo apt-get update  sudo apt-get upgrade [B[Bsudo apt-get update

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


The button in the fragment in my navigation drawer does not work. The application crashes.  I think the problem related to libraries import androidx.fragment.app.Fragment;  I want it to work when the button in my fragment is clicked.  2019-07-14 19:53:18.446 12619-12619/? E/alsix.doctorsi: Unknown bits set in runtime_flags: 0x8000 2019-07-14 19:53:19.136 12619-12682/com.medicalsix.doctorsix E/vndksupport: Could not load /vendor/lib/egl/libGLES_emulation.so from sphal namespace: dlopen failed: library "/vendor/lib/egl/libGLES_emulation.so" not found. 2019-07-14 19:53:19.136 12619-12682/com.medicalsix.doctorsix E/libEGL: load_driver(/vendor/lib/egl/libGLES_emulation.so): unknown 2019-07-14 19:53:19.696 12619-12681/com.medicalsix.doctorsix E/EGL_emulation: tid 12681: eglQueryString(923): error 0x3008 (EGL_BAD_DISPLAY) 2019-07-14 19:53:22.100 12619-12619/com.medicalsix.doctorsix E/AndroidRuntime: FATAL EXCEPTION: main     Process: com.medicalsix.doctorsix, PID: 12619     java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference         at com.medicalsix.doctorsix.First.onCreateView(First.java:40)         at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2439)         at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1460)         at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)         at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852)         at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:802)         at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625)         at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411)         at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)         at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)         at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)         at android.os.Handler.handleCallback(Handler.java:883)         at android.os.Handler.dispatchMessage(Handler.java:100)         at android.os.Looper.loop(Looper.java:214)         at android.app.ActivityThread.main(ActivityThread.java:7116)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:925)

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?


Given that bayesian probabilites are updated over time, how is this represented in a probability space? More specifically, how do we interpret the probability measure of such a space? That is, presumably such a probability measure is not preserved over time, whereas in frequentist statistics this is assumed to be invariant, so is a bayesian probability measure 'time-varying'?

Part of a series of trying to understand Bayesian vs frequentist:         I think I get the difference of how Bayesians and frequentists approach , but I'm not quite sure if or how that is supposed to explain to me how they view probability.  From what I understand, according to , a frequentist "defines" probability as follows:  Given probability space $(\Omega, \mathscr{F}, \mathbb{P})$, $\forall A \in \mathscr{F}$, $\mathbb{P}(A) \approx \frac{n_A}{n_t}$, where $n_t$ is the number of trials conducted and $n_A$ is the number of times A has occurred in those trials.  Furthermore, $\mathbb{P}(A) = \lim_{n_t \to \infty} \frac{n_A}{n_t}$.  Okay, so how do Bayesians define probability? The above seems to be one approach to computing probability of an event in addition to defining a probability.  Bayesians seems to assume a prior probability, conduct some trials and then update their probability, but that doesn't really seem to explain how they define what probability is.   says 'Bayesian probability is a quantity that we assign for the purpose of representing a state of knowledge, or a state of belief.'  What exactly does that mean? Is state synonymous to degree? For example, Walter's state of belief that a particular coin is fair is represented with the number 0.1 while Jesse's state of belief that the same coin is fair is represented with the number 0.2. Given new information, Walter's state of belief could become 0.96 while Jesse's state of belief could become 0.03. So, initially, Walter was less inclined to believe the coin is fair, but later on Jesse was more inclined to believe the coin is fair?  I'm hoping for something in terms of  like the frequentist one above.  Same Wiki page says 'The Bayesian interpretation of probability can be seen as an extension of propositional logic that enables reasoning with hypotheses, i.e., the propositions whose truth or falsity is uncertain.', it seems like Bayesian and frequentist probability are analogous to fuzzy and Boolean logic, respectively.


If one of the photons in an entangled pair produced in parametric down conversion is absorbed by an electron or atom than this elecfron must be entangled with tge other photon. In what degree of freedom is this entanglement?

If one obtains two entangled in polarization photons by parametric down conversion and one of them is accepted by and electron 1 and other by electron 2 - are this electrons now entangled in spin?


I am trying to plot the atan() function, but it keeps giving me an error. This is my code. What in the world am I doing wrong? Why doesn't it plot on the graph I made. Also I cannot use pgfplots.   \begin{tikzpicture} \draw [help lines] (-5,-pi) grid (5,pi); \draw [->,thick] (-5,0) -- (0,0) -- (5,0) node [below] {\small $x$}; \draw [->,thick] (0,-pi) -- (0,pi) node [left] {\small $y$}; \foreach \x in {-5,-4,...,5} \draw (\x, -0.1) -- (\x,0.1); \foreach \x in {-5,-4,...,-1} \node at (\x, -0.1) [below] {\tiny $\x$}; \foreach \x in {1,2,...,5} \node at (\x, -0.1) [below] {\tiny $\x$};  \draw (-0.1, -pi/2) -- (0.1,-pi/2); \draw (-0.1, -pi/4) -- (0.1,-pi/4); \draw (-0.1, pi/4) -- (0.1,pi/4); \draw (-0.1, pi/2) -- (0.1,pi/2);  \node at (-0.1, -pi/2) [left] {\tiny $-\pi/2$}; \node at (-0.1, -pi/4) [left] {\tiny $-\pi/4$}; \node at (-0.1, pi/4) [left] {\tiny $\pi/4$}; \node at (-0.1, pi/2) [left] {\tiny $\pi/2$};  \draw [scale=0.5,domain=0:5,variable=\x] plot (\x,atan(\x r));  \end{tikzpicture}

Suppose I have two points the unit circle corresponding to 30 and 60 degrees from the x-axis.  I want to draw a line between these two points.  \documentclass[border=5mm]{standalone}  \usepackage{tikz}   \usepackage{calculator}   \usetikzlibrary{rulercompass}   \usetikzlibrary{intersections,quotes,angles}   \usetikzlibrary{calc}  \begin{document}   \begin{tikzpicture}     \draw (\cos(30), \sin(30)) -- (\cos(60), \sin(60));   \end{tikzpicture} \end{document}   But this does not execute.  What is the correct way?


Ok, I'm going to try and phrase this in the such away that people don't downvote based on any implied opinion on my part.  I realize edits less than six characters are prohibited on Stack Overflow. Assuming I'm charged with explaining to someone new to SO why this is, can you provide or point me to the rationale? Please assume further that the person I'm explaining this too is particularly curious about the case of fixing typos and particularly typos in code.

I just attempted to fix a typo on a question on cooking.stackexchange.com and saw this     Oops! Your edit couldn't be submitted because:         Your edit summary must be at least 10 characters   This edit is less than 6 characters; surely more can be improved with your edit?      So, misspelled words have to just be left misspelled?  That could prevent the post from being found in a search.


I created a class Person and a HashSet. If I add the same person to the HashSet, it is not aware the Person is already present and it will add the same person multiple times. What function do I need to overwrite to have only unique elements in the HashSet?  public class Person {     public Person(int age, string name)     {         this.age = age;         this.name = name;     }      int age;     string name;      public int Age {         get { return age; }         set { age = value; }     }      public string Name {         get { return name; }         set { name = value; }     }      public override bool Equals(object obj)     {          var other = obj as Person;         if (other == null) {             return false;         }          return age == other.age && name == other.name;     } }  void Button1Click(object sender, EventArgs e) {     List<Person> allPeople = new List<Person>();     Person p = new Person(15, "John");     allPeople.Add(p);     p = new Person(22, "Michael");     allPeople.Add(p);     p = new Person(16, "Alex");     allPeople.Add(p);     p = new Person(22, "Michael");     allPeople.Add(p);     p = new Person(15, "John");     allPeople.Add(p);      HashSet<Person> hashset = new HashSet<Person>();      foreach(Person pers in allPeople) {         hashset.Add(pers);     }      foreach(Person pers in hashset) {         listBox1.Items.Add(pers.Name + ", " + pers.Age);     } }

Given the following class  public class Foo {     public int FooId { get; set; }     public string FooName { get; set; }      public override bool Equals(object obj)     {         Foo fooItem = obj as Foo;          if (fooItem == null)          {            return false;         }          return fooItem.FooId == this.FooId;     }      public override int GetHashCode()     {         // Which is preferred?          return base.GetHashCode();          //return this.FooId.GetHashCode();     } }   I have overridden the Equals method because Foo represent a row for the Foos table.  Which is the preferred method for overriding the GetHashCode?  Why is it important to override GetHashCode?


I've got a module which defines a node type. I also need to attach a few fields to this node.   I'm defining the node in hook_node_info(), and I'm creating fields in hook_install(). However, isn't this going to create the fields before the node? Isn't hook_install() executed before hook_node_info(), meaning that I'll be attempting to attach the fields to a non-existing node type at that point?  How do I define a node type programatically, and also attach fields to the node type programatically upon module installation?

Is it possible to add fields to a node type declared using hook_node_info? Do I have to add the fields separately? If so, what hook would I use for that?


I'm not particularly sure whether or not their called "Data tags", but on with the question! I wanted to be able to give myself a tripwire hook that has a custom name AND a CanDestroy tag as well. Ideas?

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


A friend and I were having a discussion about the LIGO experiments and were wondering if there is any issue with the laser light undergoing a wavelength shift as a result of the gravitational wave? Akin to the red/blue shift we see in the galactic sense but on a much smaller level.  Wouldn't this make it "impossible" to measure the length contraction since the "ruler" itself contracts within the space also?  Feel free to go into detail, but we are just looking for a simple explanation.

, Laser Interferometer Gravitational-Wave Observatory, is a large-scale physics experiment aiming to directly detect gravitational waves. The device measures the phase shift laser beams.  If I understand this well, the measurement assumes that a suitable gravitational wave reduces and prolongs one of the tubes and the extension will take effect in the phase-shifting laser beams.  But I think if there's a gravitational wave that passes through it, it will affect everything, even the laser beam. This means that when the wave lengthens or shortens the tube, it also lengthens or shortens the wavelength of the laser beam.  In my opinion, therefore, this device does not work. Or am I wrong?


Does downsizing the effective recording megapixel count setting on my P&S digital camera actually decrease the sensor-megapixel density, thereby increasing pixel size and culminating in better image quality, or is it a gimmick?  In other words, should I set the megapixel count on my 12 megapixel camera at 8 or 5 MP since I won't be printing anything larger than 4x6, if at all?  I am interested in any possible noise reduction.  My camera is a Panasonic Lumix DMC-ZS15.

Suppose you want to store your photos at some lower resolution, let's say about ~1 MB large.  You own a camera able to make photos at 5 MPix and more.  And, you want to have the maximum quality at the smaller size.  Would it be better to make a photo at highest resolution and then resize it with PC software (with a good filter of course), or to directly set the camera to make photos at 2 MPix only?


After running into some difficulties with WiFi drivers, I need the basic condition that triggers when my laptop wakes from suspension, which will then run any code beneath it. How can I achieve this?

I've got a script that is executed in order to have suspending/resuming working in my laptop. Then I have another series of xinput,xkbset and xmodmap commands that are executed when I initiate a session to have two-finger scrolling and keyboard shortcuts set up. When I resume from suspend, two-finger scrolling and my keyboard shortcuts won't work. I need to manually execute the commands in the second file again. How can I add those to the suspend/resume script to have this done automatically? See below:  suspend/resume script  /etc/pm/sleep.d/20_custom-ehci_hcd  #!/bin/sh #inspired by http://art.ubuntuforums.org/showpost.php?p=9744970&postcount=19 #...and http://thecodecentral.com/2011/01/18/fix-ubuntu-10-10-suspendhibernate-not-working-bug     # tidied by tqzzaa :)  VERSION=1.1 DEV_LIST=/tmp/usb-dev-list DRIVERS_DIR=/sys/bus/pci/drivers DRIVERS="ehci xhci" # ehci_hcd, xhci_hcd HEX="[[:xdigit:]]" MAX_BIND_ATTEMPTS=2 BIND_WAIT=0.1  unbindDev() {   echo -n > $DEV_LIST 2>/dev/null   for driver in $DRIVERS; do     DDIR=$DRIVERS_DIR/${driver}_hcd     for dev in `ls $DDIR 2>/dev/null | egrep "^$HEX+:$HEX+:$HEX"`; do       echo -n "$dev" > $DDIR/unbind       echo "$driver $dev" >> $DEV_LIST     done   done }  bindDev() {   if [ -s $DEV_LIST ]; then     while read driver dev; do       DDIR=$DRIVERS_DIR/${driver}_hcd       while [ $((MAX_BIND_ATTEMPTS)) -gt 0 ]; do           echo -n "$dev" > $DDIR/bind           if [ ! -L "$DDIR/$dev" ]; then             sleep $BIND_WAIT           else             break           fi           MAX_BIND_ATTEMPTS=$((MAX_BIND_ATTEMPTS-1))       done       done < $DEV_LIST   fi   rm $DEV_LIST 2>/dev/null }  case "$1" in   hibernate|suspend) unbindDev;;   resume|thaw)       bindDev;; esac   touchpad two-finger scrolling and keyboard shortcuts script  xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Two-Finger Scrolling" 8 1 xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Scrolling" 8 1 1 xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Pressure" 32 10 xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Width" 32 8 setxkbmap -layout gb xkbset m xkbset exp =m xmodmap -e "keycode 135 = Pointer_Button2"


I have some problem, here in my code I am trying to draw canvas on frameLayout but I am getting Null Object Reference exception. By the way when I changed Color.BLACK nothing change only show black rectangle and give error. I use android studio 2.1 and genymotion android emulator 6.0 Marshmallow  Error is like that :   Fatal Exception:main Process:com.example.myApp java.lang.NullPointerException : Attempt to invoke virtual method "void android.graphics.Canvas.rawColor(int)" on a null object reference     public class MyCanvas extends SurfaceView implements SurfaceHolder.Callback{      private boolean mRun= false;     private final SurfaceHolder mSurfaceHolder;     private final Object mRunLock = new Object();      public MyCanvas(Context context, AttributeSet attrs){          super(context,attrs);         this.setWillNotDraw(false);         mSurfaceHolder = getHolder();         mSurfaceHolder.AddCallback(this);        }      public synchronized void run(){          if(mRun){              Canvas c = null;             try{                  c = mSurfaceHolder.lockCanvas();                 synchronized (mSurfaceHolder){                     synchronized(mRunLock){                         if(mRun) doDraw(c);                     }                  }              }finally                 if(c != null)                 { mSurfaceHolder.unlockCanvasandPost(c);    }          }          }       private void onDraw(Canvas canvas){        canvas.drawColor(Color.YELLOW);     } }   my activity layout code is here.  <view class="com.example.myapp.MyCanvas"     android:layout_width="200dp"     android:layout_height="200dp"     android:lid="@+id/mycanvas" />   my activity class is here  MyCanvas myCanvas = (MyCanvas)findViewById(R.id.mycanvas); myCanvas.run();

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 would like to ask your help..  so im accessing the page number of a PDF File through this code below  this.setfPage(Double.parseDouble(pdfl.getLabelsByPageIndices()[0]));   it works fine on all other documents except for one pdf file it gives a NullPointerException pointing on the code above.. im really confused .. is my pdf file the problem?


I know this was asked , but nothing was ever changed in the system. Why should I be locked out from reviews for a week for trying to improve something? Although I know in  that the edit was not salvageable, some original posts need editing, which I would do, unchecking the "helpful" box.  When you are presented with an edited post audit and you click "Reject," you must give a reason before you pass/fail. Why should this be any different?

For the first time I failed an audit in review, but I sure don't think I should have.  I saw the edit wasn't that good, so I hit the improve button to clean things up and got this message:     This was an audit, designed to see if you were paying attention. You didn't pass. This edit vandalizes the post. Don't improve it – Reject it   Sure, I could have rejected it, but some of those can just be improved, especially if the original post needed editing.  Maybe SO could keep track of my successful improves and see that I know what I'm doing, and let me hit the improve button and not fail me for the audit.  EDIT:  I realized after it happened to me again today, that my workflow is to see that there is an error, and instead of checking the whole post, I go into edit mode, and then completely go over the post editing it as needed.  Since SO doesn't seem to want to adapt to that kind of workflow, I'll unfortunately have to change mine, or just do less.  It really slows things down to have to completely go over a post twice (kind of like the inbox zero concept, try to deal with things immediately).


I want to kill all containers from a remote machine through a ssh command. My current approach:  ssh user@website "docker kill $(docker ps -q)"   This is not working because $(docker ps -q) seems not to be working on a remote ssh code execution (While there is no problem if I have a ssh shell).  The host machine is a EC2 (AWS) with Amazon Linux.

I tried to create a user with password via ssh (with root permission) like this:  ssh root@123.45.6.7 useradd -p $(openssl passwd -1 1234) newuser   By doing so, I could successfully create an account named newuser, but I couldn't login with the expected password (which is 1234)  It makes no difference if I add double quotes:    ssh root@123.45.6.7 "useradd -p $(openssl passwd -1 1234) newuser"   And then I was wondering if I can generate hashed password and save it as a variable locally, but still with no luck.  password=$(openssl passwd -1 1234) ssh root@123.45.6.7 "useradd -p $password newuser"   Is there something that I miss? Thanks in advance!


I am new to install ubuntu. I want to install it using boot able usb. My question is how much size usb drive required for making bootable ubuntu operating operating system?

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.).


How can I export my blender file to unity so it saves all materials and textures?

I exported a .fbx file to Unity 3D, but it retained none of the applied textures.  Is there a way to create a textured model in Blender and export it into Unity while retaining the textures, without having to export my UV layout and retexture it again within Unity?


I happen to have ~36k rep on Stack Overflow, placing me in the top 0.67% overall, despite only posting about 20 questions in the past 8 years, non of which got over 10 upvotes. This makes me happy, since I get to proudly show of my status, while not having to do anything to support it. Compound interest does the rest. But I wonder how fair this is to people starting on the platform today. Society has various ways to solve this problem, and one of those is inheritance tax. I wonder if we could have a mechanism that removes say 1% of your reputation every year. (The exact amount would need to be specified a bit more carefully). This would be barely noticeable to young accounts with lots of activity - they would be gaining reputation faster than losing it. But for an account like mine, that would mean loosing several hundred points every year. Hopefully that would roughly balance out the steady trickle of compound interest and leave these accounts with roughly the same amount of reputation they gained whilst being active.

I see profiles of , ,  etc and realize that even if they were to go inactive, it'll take years to beat them in terms of total rep, because they'll hit the rep cap every single day, thanks to their popular old answers for years to come.  I do realize, the answers totally deserve the rep they get, they are brilliant! But they do have to stop generating rep at some point to be fair right?


I have a valid German visa, which I could not use in the time period allowed. So I will not enter Germany with the current visa. But I need to travel to Germany two weeks after the visa expiry.  Can I get a new visa or extend the current visa? Is there any policy for visa stamping if the previous visa hasn't been used?

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


Now I can change it by Fn+ arrow right but now I need  to do it via my shell script

To work around  (changing LCD brightness via hotkeys impossible), I'd like to have one command line query for increasing and one for reducing the brightness of my LCD. I could then map a hotkey to each one of this queries.  The problem is: I don't know how to increase and reduce the LCD brightness on the command line. Do you?


I am writing a document on writelatex.com and I get an error with this:  \begin{equation}  [any text here returns an error]  \end{equation}   The error message is      Display math should end with $$.   I don't undestand this and I can't understand what the problem is, I have other documents when this code works fine. Is it possible that I'm missing some package?

I'm getting errors in a matrix equation. When I compile it looks fine, but I'd like to fix them so I don't have to press return for every error at compile time. The code for the equation is:  \begin{equation*}  \begin{bmatrix} U(1,t)  & \cdots & U(n,t) \\  \vdots & \ddots & \vdots \\ O_{n1} & \cdots & O_{nn}  \end{bmatrix} \times \begin{bmatrix} W(1,1)  & \cdots & W(1,n) \\  \vdots & \ddots & \vdots \\  W(n,1) & \cdots & W(n,n)  \end{bmatrix} = \begin{bmatrix}  D(1,t)  & \cdots & D(n,t) \\ \vdots & \ddots & \vdots \\ I_{n1} & \cdots & I_{nn} \end{bmatrix}  \end{equation*}   The errors I'm getting are related to missing $'s inserted.


My application requires me to drop voltage from 12v to 6v or any other lower voltage.  I have used resistors but they are not efficient for prolonged use as they tend to heat up and burn my fuse. I want to know whether there are any other IC or a simple circuit which 'll be small in size, inexpensive, efficient and does not heat up much to cause problem.

I have been looking around for an easy way to convert 12V to 5V. I have seen some people saying that a simple resistor is all that is needed.  $$ Volts = Ohms \cdot Amps $$ $$ Amps  = \frac{Volts}{Ohms} $$ $$Ohms  = \frac{Volts}{Amps}$$  So applying a resistor will diminish the voltage of the circuit. That should mean that an appropriately sized resistor could simply be placed in the path of a 12V circuit, converting it to 5v.   If this is the case how would one reduce amps? Would series vs parallel make a difference in this area?   I have seen designs that include a regulator IC and some capacitors, but if a simple resistor/fuse/diode setup will do the trick, I would really prefer that.


To find out the greatest among the number given below:  $3^{1/3}, 2^{1/2}, 6^{1/6}, 1, 7^{1/7}$  I have plotted the following graph using graph plotter which is shown below:   It can be concluded that $3^{1/3}$ is the greatest. I want to know that is there any other method to find greatest among the such numbers.

$1, 2^{1/2}, 3^{1/3}, 4^{1/4}, 5^{1/5}, 6^{1/6} , 7^{1/7}$. I got this question in an Application of Derivatives test. I think log might be used here to compare the values, but even then the values are very close to each other and differ by less than 0.02, which makes it difficult to get some specific answer to this question. How to solve this by a definite method?


It occurred to me, while watching the movies, that Harry could have died doing any number of things, and Death Eaters had plenty of chances to kill him. But Voldemort had specific orders, Harry was his to kill.  The prophecy, any prophecy, by definition, is just a telling of things to come. It isn't some law regarding what must happen. Shouldn't Voldemort, knowing this, just had someone off Harry? Was this just a long story of someone's pride being their downfall?   I'm not asking why Voldemort had to kill Harry as Dumbledore said (Dumbledore knew there was a piece of Voldemort's soul to kill). That is .  What I'm asking, is:   Why didn't Voldemort just put a nice bounty on him and be done with it?

‘So the boy ... the boy must die?’ asked Snape, quite calmly.   ‘And Voldemort himself must do it, Severus. That is essential.’   Deathly Hallows - page 551 - UK Hardcover - chapter 33, The Prince's Tale   Dumbledore tells Snape it is 'essential' that Voldemort be the one to kill Harry, I'm assuming in order for the piece of Voldemort's soul in Harry to be properly killed as well.  But why?   Hermione destroyed the Hufflepuff cup; Ron destroyed the Slytherin locket; Neville killed Nagini; Harry destroyed the diadem and Tom Riddle's diary. So the Horcruxes were not immune to destruction at the hand of someone other than Voldemort. And as it ended up, Harry himself wasn't even a Horcrux, but rather just an unknowing host to a parasitic bit of Voldemort's soul.   Why was it 'essential' that Voldemort be the one to kill Harry in order for the piece of Voldemort's soul to die?


For an independent t-test, if my hypothesis states there will be no significant difference between the two groups, is that a one- or two-tailed test?

While studying for my stats course, I was trying to understand the difference between one-tailed and two-tailed hypothesis tests. Specifically, why does the one-tailed test reject the null while the two-tailed one does not?   An example:


I'm in the second year of my mechanical engineering bachelor and I've recently started exploring the field of machine learning online. My question is this: which specific subjects do people learn, and in what order, when they study machine learning in college? Also, which books would you recommend? I'm NOT asking which online courses to take, I just want to know which SUBJECTS you were taught in college. For example, I've been doing a lot of reading lately, and it was only yesterday that I came across discriminative/generative networks, yet it seems important to me.   I'm nearly done with prof. Andrew Ng's course on Coursera, but I feel like I'm missing out on a lot of details and concepts. I'd like to hear which subjects you studied (and perhaps in what order).

I'm starting to want to advance my own skillset and I've always been fascinated by machine learning. However, six years ago instead of pursuing this I decided to take a completely unrelated degree to computer science.   I have been developing software and applications for about 8-10 years now, so I have a good handle but I just can't seem to penetrate the maths side of machine learning/probabilities/statistics.   I start looking at learning material and on the first page it might include something which confuses me and immediately sets up a barrier in my learning.   Is a strong background in maths a total requisite for ML? Should I try and fill in the blanks of my maths before continuing with ML? Can self learning really work for just a developer without any hard computer science background?    Related question:


I have been using a MacBook charger for about 6 months, and now I tried to use another one which I have used before with this MacBook.   Now, the battery is low enough that the MacBook can’t start, but only display the battery icon on the screen.  When connecting it to the power, the charger led turns green, then red (signaling that it is charging) and finally, turns off (after about 15 seconds).   I tried cooling down the MacBook and the charger, and after that I tried recharging. It did work for a longer time, but then the behavior explained above appeared again.  Why is this happening? How can I fix it?    The other charger does work. This charger stops working once the MacBook is started (or woke up from sleep).

I experienced this behavior two days ago (My MacBook Air is late 2011 version (4.2):   I can still power up my Mac, with or without MacSafe charger connected Battery is not charging There is no light. I tried to reset SMC but it does not help Battery condition is normal I tried with few different MagSafe charger but still can't charge my MacBook Air   What is the problem and what should I do?  Here is the result of System Information:  Battery Information:    Model Information:   Serial Number:    xxxxxxxxxx   Manufacturer: SMP   Device Name:  bq20z451   Pack Lot Code:    0   PCB Lot Code: 0   Firmware Version: 406   Hardware Revision:    000a   Cell Revision:    162   Charge Information:   Charge Remaining (mAh):   4743   Fully Charged:    No   Charging: No   Full Charge Capacity (mAh):   5788   Health Information:   Cycle Count:  269   Condition:    Normal   Battery Installed:    Yes   Amperage (mA):    0   Voltage (mV): 8032  System Power Settings:    AC Power:   System Sleep Timer (Minutes): 10   Disk Sleep Timer (Minutes):   10   Display Sleep Timer (Minutes):    10   Wake on AC Change:    No   Wake on Clamshell Open:   Yes   Wake on LAN:  Yes   Current Power Source: Yes   DarkWakeBackgroundTasks:  1   Display Sleep Uses Dim:   Yes   PrioritizeNetworkReachabilityOverSleep:   0   Standby Delay:    4200   Standby Enabled:  1   Battery Power:   System Sleep Timer (Minutes): 10   Disk Sleep Timer (Minutes):   10   Display Sleep Timer (Minutes):    2   Wake on AC Change:    No   Wake on Clamshell Open:   Yes   DarkWakeBackgroundTasks:  0   Display Sleep Uses Dim:   Yes   Reduce Brightness:    Yes   Standby Delay:    4200   Standby Enabled:  1  Hardware Configuration:    UPS Installed:    No  AC Charger Information:    Connected:    Yes   ID:   0x0000   Revision: 0x0000   Family:   0x0000   Serial Number:    0x00000000   Charging: No


i just want fix the footer to the bottom of the web. I searched for answers but when i apply the position the "box" isn't complete Here are some imgs     footer {     position:fixed;     bottom:0;     clear:both;     background-color: #22AAAA;      font-size: 25px;      text-align: center;     padding-right: 5px;     font-family: 'Cedarville Cursive', cursive; }
Made at 5am

I have a simple 2-column layout with a footer that clears both the right and left div in my markup.  My problem is that I can't get the footer to stay at the bottom of the page in all browsers.  It works if the content pushes the footer down, but that's not always the case.


What is the best way to get smartphone access when traveling for a few days in South Korea? I am mostly interested in getting cheap data access (google maps...).

Next month I am traveling to country X, where I would need Y minutes of calls, Z text messages and most importantly Q megabytes of data. How can I find the cheapest/most reliable SIM card for my needs?


We have a rogue locked in a cell and he is trying to escape.   How many attempts does he get to try and unlock the same door with the same hairpin if no outside influences ever change?  I have a vague memory somewhere of a rule from maybe 2nd edition D&D that unless conditions change the character's roll (and hence their caged status) does not change no matter how long the character waits and they may only re-roll if something happens to improve their situation. For instance: their skill level improves from leveling up, they find a set of proper lockpicks, a second character is helping work the lock, etc.  I know many DMs that allow characters to re-roll these types of skill checks once a day, or every hour, or sometimes every 15 minutes. Is there a hard rule on this?

Picking a lock typically requires a DC 15 Dexterity check (Basic rules, p. 49). Likewise for manacles (p. 50), which can alternately be escaped with a DC 20 Dexterity check or broken with a DC 20 Strength check. But what happens if you fail?  The general rules for ability checks state (p. 58):     If the total equals or exceeds the DC, the ability check is a success—the creature overcomes the challenge at hand. Otherwise, it’s a failure, which means the character or monster makes no progress toward the objective or makes progress combined with a setback determined by the DM.   As a DM, how can I handle this in practice? In our last session, the players wanted to get inside a locked building to rescue people trapped inside. Picking the lock seemed like an easy enough task for the rogue, but unluckily he failed the check, and I wasn’t prepared for the consequences. There wasn’t much time pressure and no obvious reason why he couldn’t try again, so I allowed another attempt, but it just didn’t feel right.  I’m sure that similar situations will come up again, so I’d like some advice on how to deal with checks so that they don’t just turn into a tedious exercise of rolling until you succeed. I presume that  was left out of the game for good reason, but I’m not sure what to do instead. I suspect that this was a good occasion to use “progress with a setback” but that’s a fairly new thing for D&D and I’m not sure how to go about it. I’m unsure when I should use setbacks versus lack of progress, and in the latter case I’m unsure when I should allow players to try again versus requiring a different approach.  For example, suppose that a manacled player tries to pick the lock and fails the DC 15 Dexterity check. Now, the player could try to pick it again, or he could try one of the other escape methods, or he could wait for somebody else to rescue him, or he could simply succeed with some setback like a minor injury. How do I choose how to proceed? Or do I let the players choose?


Is there a surjective map $f:X\to X$ on compact metric spcace $(X, d)$ with the following condition?  There is $0<L<1$ such that $d(f(x), f(y))<Ld(x, y)$  for all $x,y\in X$

This question is from Foundations of mathematical analysis by Richard Johnsonbaugh   The thing with this question is that there is a question that seems to prove the opposite claim  - someone look into this  How should one go about dealing with this question?


I'm using the below code to retrieve a file from db using Spring Boot JPA.  But it's returning null value.   PS. There is no problem with DB connection. I can save values using the repository but problem occurs while retrieving value using ID.  Can anyone please give me a solution ?  @RequestMapping(value = "/fetch/{id}", method = RequestMethod.GET) public List<Page> getData(@PathVariable String id) {      try {             FileDB file = fileRepository.findOne(Long.parseLong(id));             Document doc = file.getDocument();             List<Page> pages = doc.getPages();             return pages;          } catch (Exception e) {             System.out.println(e.toString());             List<Page> pages = new ArrayList<>();             return pages;         } }

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?


Since the electrostatic field and the Newtonian gravitational field share a similar form: proportional to   $$  \frac{1}{r^2} $$  Is there any qualitative difference between motions under the influence of electric field and gravitational field?

In classical mechanics, we had Newton's law of gravity $F \propto \frac{Mm}{r^2}$.  Because of this, all laws of classical electrostatics applied to classical gravity if we assumed that all charges attracted each other due to Coulomb's law being analogous.  We can "tweak" classical electrostatics to fit gravity.  In modern physics, does the reverse work?  Can we "tweak" General Relativity to accurately describe electrostatics or even electromagnetism?


Lets say I have a really long string that I need to have across multiple lines in the text editor for readability. Should I use StringBuffer or does it not matter? In other words is this:  string my_string = "there are lots of " + "words here";   The same as this as far as performance goes?  string my_string = "there are lots of words here";   In other words, will I be creating multiple string objects in the first example and only one in the second? I want to make sure performance doesn`t suffer for readability purposes.

For instance, does the compiler know to translate  string s = "test " + "this " + "function";   to  string s = "test this function";   and thus avoid the performance hit with the string concatenation?


I've a folder with a file list. All files have the same root name but change in order on its refere date, as follow: This is my wished alfabetically order:  MyName - 202003.pdf MyName - 202006.pdf MyName - 20200708.pdf <------ MyName - 202009.pdf MyName - 202011.pdf MyName - 202012.pdf MyName - 202101.pdf MyName - 202102.pdf  But in my folder the order is:  MyName - 202003.pdf MyName - 202006.pdf MyName - 202009.pdf MyName - 202011.pdf MyName - 202012.pdf MyName - 202101.pdf MyName - 202102.pdf MyName - 20200708.pdf <------  I've already checked the right configuration about the folder order (Name - ascending) but the last file is in wrong position. You have notice about this bug? I can fix it?

The behaviour described below occurs on Windows-7 systems and on Windows XP. We operate in a dual-language environment - English and Hebrew.  When in Windows Explorer we sort files by name, the order in which they are listed is not what we would expect. Here is a list of file names as sorted by Windows Explorer (all of the files have a .pdf suffix):   1G110033H-PP 19C050G-PP-ORB 19C050H-PPRM 19C100H-PPRM 19C-MBPS-PP 19C-MBPS-PP-1 29AAC050-PP 29AAC100-PP 29AAC100-PPUL   29B004064-PP 101AC050-PP 101AC100-PP 101B100-PPE 1091003G-PPFSUL 10108033G-PPSA 10125033H-PPM     It looks to me that first the items are sorted according to the position of the first alphabetic character in the name, and then, within those groups, they are sorted in "normal" alpha-numeric order.  That is, all the files with an alpha character in the first position are on top of the list, followed by those with the first alpha character in the second position, followed by those with the first alpha character in the third position, and so on.  An alternate way of looking at this is that, in a file name composed of numbers and letters, the sort treats the first group of numbers in the name as the major sort node, with the rest of the name being the secondary sort node.  Now that I understand the sequencing logic, it's not a big problem, but I was wondering why this happens?


I see that Citrix Receiver is currently available for Ubuntu 13.10, and there are threads about installing it on Ubuntu 14.04 64-bit. Is there any way to install it on Lubuntu 14.04 32-bit?

Has anyone managed to get the Citrix receiver client (icaclient) working in Ubuntu?


Hi got my schengen visa for 3 weeks validity but duration of stay shows 10 days, how long i can stay 10 days or 3 weeks please help

I'm from Tunisia and I got a Schengen visa from the Austrian Embassy for  28 days, the “duration of stay”, and the number of entries is 1. But the validity of the visa is from 02/08/2015 to 13/09/2015.  Do I have to stay only 28 days, for example from 02/08/2015 to 29/08/2015 or can I stay there until 12/09/2015 ?  And if I have got to stay only 28 days, then can I choose the days of stay, that's mean can I stay in Austria for example from 09/08/2015 to 05/09/2015?


Active:     Don't ask me the question.   Passive:     Don't let myself be asked the question by you.   Is it correct? If not, please provide the correct answer.

How would you convert the imperative sentence: "Go to school now." to the passive voice?  While discussing it in class, our teacher gave the following solution: "You are ordered to go to school now."  However, I felt that this must be wrong, since the sentence is still in the active voice. It seems to be in the passive voice with reference to the verb 'order', but we need to convert the sentence with respect to the verb 'go'.  I thought of a solution: "Let you be gone to school now." or "Be gone to school now."  Are any of them correct? And if not, how would you convert the sentence into passive voice?    Edit:  Just realised that 'go' is an intratransitive verb. Does that mean that there won't be a passive version of it? As mentioned :     You CAN'T. You can only turn into passive verbs those verbs who can have the "direct object".   For example:   I eat (what do you eat?) an apple   I see (what do you see?) a bird   I read (what do you read?) a poem        But if you say : I go, you can't ask "what do you go", because it doesn't make any sense! And that's why you can't write that in passive voice.     Edit II:  How about "Let the school be gone to by you."?


root@server1:~# apt-get update Err http://archive.ubuntu.com lucid Release.gpg   Temporary failure resolving 'archive.ubuntu.com' 0% [Connecting to archive.ubuntu.com]   I can't get it work, any issues?  I use Ubuntu 10.04.

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


How could I prove that $\Bbb Q({\sqrt2},{\sqrt3})$ and $\Bbb Q(2^\frac{1}{4}))$ aren't isomorphic? I need to prove it and I don't know how, but it seems easy. Thanks everybody.

I wish to show that $\mathbb{Q}(\sqrt2, \sqrt3)$ is not isomorphic to $\mathbb{Q}(\sqrt[4]2)$.    What I did so far was to show that $\mathbb{Q}(\sqrt2,\sqrt3) =\text{span}\{1,\sqrt2,\sqrt3,\sqrt6\}$.  Assuming they are isomorphic, denoting $f$ the isomorphism, then $f(1) = 1$, so $x^2-3$ has a root in $\mathbb{Q}(\sqrt2,\sqrt3)$ so $\sqrt 3\in\mathbb{Q}(\sqrt[4]2)$. ($\sqrt2 \in \mathbb{Q}(\sqrt[4]2)$, $\sqrt[4]2\cdot\sqrt[4]2=\sqrt2)$.   Thus under the assumption, $\mathbb{Q}(\sqrt2, \sqrt3)\subseteq \mathbb{Q}(\sqrt[4]2)$. As a vector spaces of the same dimension over $\mathbb{Q}$, it means that $\mathbb{Q}(\sqrt2, \sqrt3)= \mathbb{Q}(\sqrt[4]2)$.  Now all is left to do it to show a contradiction: $\sqrt[4]2\in\mathbb{Q}(\sqrt2,\sqrt3)$, then $\sqrt[4]2 = a+b\sqrt2+c\sqrt3+d\sqrt6$ so $2=(a+b\sqrt2+c\sqrt3+d\sqrt6)^4$, I believe that opening the expression, I would find out that it can't be an element of $\mathbb{Z}$. However this is a really inelegant way (if it really works), and I wish for a better way to do so.  An other approach: $\mathbb{Q}(\sqrt2,\sqrt3) = \mathbb{Q}(\sqrt2 + \sqrt3)$ by the irreducibility of $x^4-10x^2+1$ over $\mathbb{Q}$ (an some dimension theorem usage). Also, $x^4-10x^2+1$ splits in $\mathbb{Q(\sqrt2, \sqrt3)}$.   Is there a way to show that this polynomial doesn't split over $\mathbb{Q}(\sqrt[2]4)$? with different method then assuming that $\sqrt3\in\mathbb{Q}(\sqrt[4]2)$ and getting a contradiction? Maybe the fact that $\sqrt[4]2$ has complex roots might help?


Always a have problem when I install any version of ubuntu, but in this opportunity I can't solve the issue. My wifi connection down after 1 or 2 minutes in Ubuntu 17.04, it's so unstable, I already tried with:  apt install firmware-b43-installer   I have read so many articles in internet about the issue and nothing solve the problem, only change the time of issue ie the wifi get down in 2 minutes or in 10 minutes or in 1 more day but always get down, I do not know what doing. These are the tech features of my notebook when I execute these commands:     lspci -nn   Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]   and      lspci -knn | grep Net -A2   Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]  Subsystem: Lenovo RTL8821AE 802.11ac PCIe Wireless Network Adapter [17aa:a814] Kernel driver in use: rtl8821ae Kernel modules: rtl8821ae   This is my kernel info:     uname -mrs   Linux 4.10.0-20-generic x86_64   My notebook is a Lenovo 310-14IKB. I am not what more doing

I have continuous problems of network dropping connections on wifi with ubuntu 16.04, I have an ASUS R510J, this is my network card:  ##### lspci #############################  03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]         Subsystem: AzureWave RTL8821AE 802.11ac PCIe Wireless Network Adapter [1a3b:2161]         Kernel driver in use: rtl8821ae  04:00.1 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 12)         Subsystem: ASUSTeK Computer Inc. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [1043:200f]         Kernel driver in use: r8169   sudo service network-manager restart doesnt's help, as I never regain internet connection after it drops, and I have to restart the PC. On Ethernet cable I have no problem.  What do you think is the issue? drivers?  thank you


I recently installed Ubuntu on an ancient PC. Its fantastic, but I don't have any sort of internet connection at home. I was wondering if It would be possible to download a package and its dependencies on my School computer (Windows 8.1), move them to a USB drive, and install them on my offline Ubuntu PC. I've heard of Synaptic, but I don't know how to install it on my offline PC and don't know if it supports Windows. Any help or suggestions?

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


since we know that X and Y are independent, then the pair $(XY^c)$, $(X^cY)$, $(X^cY^c)$ also independent.

Let I have $(S,\Sigma,\mu)$ be a probability space, then $X,Y \in \Sigma$. Define $\rho (X,Y)$ by $\rho (X,Y)$ = correlation between random variable $I_X$ and $I_Y$, where $I_X$ and $I_Y$ are the indicator function of $X$ and $Y$. Express $\rho (X,Y)$ in term of $\mu (X)$, $\mu (Y)$, $\mu(XY)$. Conclude that $\rho(X,Y)=0$, if and only if $X$ and $Y$ are independent.      How to show that: $$\rho(X,Y)= \frac{\mu(XY)\,\mu(X^cY^c)-\mu(XY^c)\,\mu(X^cY)}{(\mu(X) \,\mu(X^c)-\mu(Y) \,\mu(Y^c))^{1/2}};0<\mu(X)<1;\,0<\mu(Y)<1$$


I’d like to use  to transform all images from the current directory to a video. The image file name is not like, image1.jpg and image2.jpg.

I'm trying to convert a series of JPEG images into a time lapse video. They're in the format IMGP0001.JPG, IMGP0002.JPG, etc. From the looks of things, this should match the pattern IMGP%04.JPG.  I've tried the following commands :  ffmpeg -f image2 -i IMGP%04d.jpg video.mpg   I get the error "IMGP%04d.JPG: No such file or directory".   What am I doing wrong? Perhaps the syntax "IMGP%04d.JPG" is *nix specific? If so what would be the Windows equivalent?


I studying the proof that the Petersen graph is not Hamiltonian, and in the proof, they used an observation that seems intuitively correct but I want to provide rigorous proof for it, given that I'm taking an introductory course to discrete mathematics.  Claim: Petersen graph has no cycles less than or equal to 4  I want to prove it by contradiction using the basics ideas, can you help me with that?

I want to know, what is the mathematical proof that shows the shortest cycle in Petersen Graph has length five?


I'm working with an application that provides date times strings containing timezones. Here is an example:  21/07/2011 10:42 AM BST   When I parse this using DateTime.Parse, including specifying the British locale...  [TestMethod] public void ParseDateStringWithBSTTimeZone() {     string dateString = "21/07/2011 10:42 AM BST";     var date = DateTime.Parse(dateString, CultureInfo.CreateSpecificCulture("en-GB"));     Assert.AreEqual(new DateTime(2011, 7, 21, 9, 42, 0), date); }   I get the following error:  System.FormatException: The string was not recognized as a valid DateTime. There is an unknown word starting at index 20.   How can I parse this date time string? Doesn't .NET DateTime library support dates with this format?

I'm trying to parse an international datetime string similar to:  24-okt-08 21:09:06 CEST   So far I've got something like:  CultureInfo culture = CultureInfo.CreateSpecificCulture("nl-BE"); DateTime dt = DateTime.ParseExact("24-okt-08 21:09:06 CEST",     "dd-MMM-yy HH:mm:ss ...", culture);   The problem is what should I use for the '...' in the format string? Looking at the  MSDN page doesn't seem to list a format string for parsing timezones in PST/CEST/GMT/UTC form.


All company shares payout very small amounts in dividends. What is the big interest for an investor to spend tens of thousands of dollars in stocks to possibly earn maybe $1,000 per year or so in dividends? I see no big advantage there. It comprises this one pitfall that I can't get around:  Big amounts of money needed to be invested up front or over time for very small returns over time.  As an investor who wants to earn money in the near future, what would the interest be for me to invest big amounts of money for returns that won't even count as profit until many years down the road?  Even assuming I do profit, how much is the question, and will it be worth it for me to spend lots of my money to wait far down the line in life to get menial returns?   That doesn't sound appealing to me as an investor, because how does that help my "current life?"  I'm not looking for retirement -- I'm looking for money in my younger years with investing and I can't get my head around why I should invest so much money when the return is always small and slow.  No, I don't plan to get rich overnight. I also don't plan to count pennies of profit when I'm 50 either.

I understand that a dividend is a way for a company to return money to shareholders. But I'm not quite understanding why it is preferable to capital appreciation and putting the money to work increasing the earnings and revenue of the company. I get that people who buy stocks to get income from dividends, but the decrease in the price of a stock that correlates directly to the amount of the dividend seems to me like it's a zero-sum game.  Part of me thinks that I just fall into the Warren Buffet camp of thought that the money can be spent more wisely in house. But the other part feels like the desire for a dividend is to reinvest and add shares at a lower price (the price the stock goes to ex-dividend).   What am I missing here?


Can I use Apple's fonts in my Atom text editor.  seems to suggest I can't. Can anyone confirm this? I know, of course, Apple has no way of finding out if I do. I just don't want to use it if I'm not allowed to.

I thought the new Apple font was called San Francisco, but I cannot find it in the font list of the Keynote.app for my Mac. Is it called another way or it is not available for Keynote?  I am currently using OS X El Capitan.


NOTE: This is not a question about auto-implemented properties. Auto-implemented properties are about properties without logic in the getters and setters while I stated in my code very clearly that there is some logic. This is not a duplicate of  nither, since the question is really different, and so is the answer.  I see a lot of this: private int _age; public int Age {     get     {         if(user.IsAuthorized)         {             return _age;         }     }     set     {         if(value >= 0 && value <= 120)         {             _age = value;         }         else         {             throw new ArgumentOutOfRangeException("Age","We do not accept immortals, nor unborn humans...");         }     } }  But why do we need the backing field? Why no returning the Property itself? public object Age {     get     {         if(user.IsAuthorized)         {             return Age;         }     }     set     {         if(value >= 0 && value <= 120)         {             Age = value;         }         else         {             throw new ArgumentOutOfRangeException("Age","We do not accept immortals, nor unborn humans...");         }     } }

Note: This was posted when I was starting out C#. With 2014 knowledge, I can truly say that auto-properties are among the best things that ever happened to the C# language.  I am used to create my properties in C# using a private and a public field:  private string title; public string Title {     get { return title;  }     set { title = value;  } }   Now, with  3.0, we got auto-properties:  public string Title { get; set; }   I know this is more a philosophical/subjective questions, but is there any reason to use these auto-properties except from saving five lines of code for each field? My personal gripe is that those properties are hiding stuff from me, and I am not a big fan of black magic.  In fact, the hidden private field does not even show up in the debugger, which is OK given the fact that the get/set functions do nothing. But when I want to actually implement some getter/setter logic, I have to use the private/public pair anyway.  I see the benefit that I save a lot of code (one vs six lines) without losing the ability to change the getter/setter logic later, but then again I can already do that by simply declaring a public field "Public string Title" without the need of the { get; set; } block, thus even saving more code.  So, what am I missing here? Why would anyone actually want to use auto-properties?


I am (deliberately) still running XP on my main home PC.  Since the attack of the WannaCry ransomware, I have been unable to reach Windows Update (or any other Microsoft website) with Internet Explorer.  I have seen no other indication of being attacked.  Do I have a problem?  If so, is there anything I can do about it?  And what can I do to prevent problems in the future?  Thanks for any advice, Howard French

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


What decade? Any particular reason?  This is an etymological/historical question, not a grammar question.

What's the deal with the phrase "could care less"?  Whilst growing up, I've always known people (parents etc) to use the phrase "couldn't care less", but I've also come across people who use the phrase "could care less" to mean the same thing (that is, "I do not care at all about that").  To me "couldn't care less" seems a lot more logical. If I couldn't care less about something, that implies I do not care about it at all. In contrast to this, to my mind the phrase "could care less" seems to indicate "I do care about this to some degree at least", but that's definitely not the meaning intended.  What's going on here? Is my (logical) analysis correct or in error?


I'm new learning as I go, I have read some of the Answers posted, and I've gotten this far, I was able to add a new field to a GBD, I wanted to have the Length be 50, but it created a field with 255, so I didn't get something quite right  the code I used  below  the feature class is wax_ru the Field name is HN_AW  Text is the Type of Field, and 50 is the Default Value I wanted, but as I stated it created the field with 255  import arcpy from arcpy import env env.workspace = "C:\Users\angelaw\OneDrive - TomTom\Resources\Australia\PSMA_MAY_2018\PSMA_Deltas_test\PSMA_MAY_deltas.gdb"  arcpy.AddField_management ("wax_ru", "HN_AW","TEXT",50)

I have to try to add a field called 'Name' to a bunch of different feature classes using python, and then access the name of the feature class to fill in the field. I have no idea how to even start this! I know I need a loop but that's all I know.


What exactly is type coercion in Javascript?  For example, on the use of == instead of ===?

I'm using  to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value.length == 0 inside of an if statement.  Is there a performance benefit to replacing == with ===?   Any performance improvement would be welcomed as many comparison operators exist.  If no type conversion takes place, would there be a performance gain over ==?


Earlier today I was on my iPhone and it randomly froze so I turned it off. When I went to unlock it it wouldn't move. I couldn't unlock it or tap anything. So now I can only stay on the lock screen. I read on the Apple website that I should "force restart" it by pressing my home button and power button at the same time. The problem is my home button is stuck and doesn't work. What should I do?

my home button on my ipod touch 5th Gen has been broken for  while so I have been using assistive touch. Earlier on my notification centre got stuck half way down the lock screen, making my ipod completely unusable.   I tried turning it off but the notification centre is blocking the slider and obviously I can't restart it since my home button is broken. Has anyone got any solutions? It's an absolute nightmare!


Normally when conducting an F-Test one is hoping the F-Test of all variables is significant although the single T-Tests yield insignificant results.  But can the reverse also be true? That is a worse F-Test than the single T-Tests?

I'm fitting a multiple linear regression model between 4 categorical variables (with 4 levels each) and a numerical output. My dataset has 43 observations.  Regression gives me the following $p$-values from the $t$-test for every slope coefficient: $.15, .67, .27, .02$. Thus, the coefficient for the 4th predictor is significant at $\alpha = .05$ confidence level.  On the other hand, the regression gives me a $p$-value from an overall $F$-test of the null hypothesis that all my slope coefficients are equal to zero. For my dataset, this $p$-value is $.11$.  My question: how should I interpret these results? Which $p$-value should I use and why? Is the coefficient for the 4th variable significantly different from $0$ at the $\alpha = .05$ confidence level?  I've seen a related question, , but there was an opposite situation: high $t$-test $p$-values and low $F$-test $p$-value. Honestly, I don't quite understand why we would need an $F$-test in addition to a $t$-test to see if linear regression coefficients are significantly different from zero.


I'm pretty sure this is a duplicate somewhere. I apologize for the repeat. I'm running Xubuntu 14.04. For some odd reason my pc is running slow today, so I thought it might have something to do with the software, so I did an update, and sudo apt-get update returns an error:  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   I tried the answer given in   and this is the following result:  $ sudo lsof /var/lib/dpkg/lock lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete. COMMAND   PID USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME aptitude 2166 root    3uW  REG  252,0        0 49021509 /var/lib/dpkg/lock  $ sudo lsof /var/lib/apt/lists/lock lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete.  $ sudo lsof /var/cache/apt/archives/lock lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete.  $ sudo dpkg --configure -a dpkg: error: dpkg status database is locked by another process    How do I fix this? Could someone walk me thru the steps?  Why would I need a "lock" on an open directory?  How do I find what process is using it? How do I check my hardware if that's the culprit??   I will try a reboot, and see if that fixes anything. Be right back.    OK, NOW after rebooting I get the following results:|  $ sudo lsof /var/lib/dpkg/lock lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete.  $ sudo lsof /var/lib/apt/lists/lock lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete.  $ sudo lsof /var/cache/apt/archives/lock lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete. lsof: status error on /var/cache/apt/archives/lock: No such file or directory lsof 4.86  latest revision: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/  latest FAQ: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/FAQ  latest man page: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/lsof_man  usage: [-?abhKlnNoOPRtUvVX] [+|-c c] [+|-d s] [+D D] [+|-f[gG]] [+|-e s]  [-F [f]] [-g [s]] [-i [i]] [+|-L [l]] [+m [m]] [+|-M] [-o [o]] [-p s] [+|-r [t]] [-s [p:s]] [-S [t]] [-T [t]] [-u s] [+|-w] [-x [fl]] [--] [names] Use the ``-h'' option to get more help information.   I also tried  sudo dpkg --configure -a   which may have worked cause when I did  sudo apt-get update   I got NO ERRORS.

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?