I got a two-year multiple entry visa on May 20, 2014 to attend a conference in California. Unfortunately for me, my company cancelled my leave because of an unexpected project we secured from Shell Nigeria.  Can I still use the same visa to visit the USA? I leave next month and I wish to visit the USA, but now I am thinking it might not be allowed.

Note: This is NOT a duplicate of  Difference: In both other questions, the posters traveled once to the US for the original purpose for which the B1 visa was obtained. Their question is about visiting again using the same visa. However, I've not traveled to the US yet, and I'm planning my visit. What I want to understand whether I can use this visa for a visit whose purpose is not the same as what was submitted along with the application.  Can I use a B1/B2 visa for tourism that was originally obtained for business purposes BEFORE I actually visit the US even once? I had applied for a business visitor visa for a valid business reason but by the time I got it stamped, my plan changed. So I've not visited the US even once. Can I now use this visa to visit as a tourist without having used that visa for its original intended purpose? PS: I live in India.


I know there must be a good reason why the one tag limit must be in place, but I can't really see a good reason why. From my perspective, I often would like to reply to two or more users with the same message, but to do so I have to write to separate comments.   Could someone please enlighten my as to why the one tag limit exists, and/or can we make it possible to tag multiple users in a comment?

Now this is probably a surprise to many since I always see thousands of comments like :  @Sarfraz, @balpha just told you they did in the first comment he wrote. Also, allowing only one Stack Overflow user to be logged in per IP address would be problematic for networks with shared IPs.  What's surprising is that apparently the notification will trigger only for Sarfraz and not for balpha. As you can see from the :  Only one person can be replied to at a time in a comment. The first one in the string wins.  I propose to increase the limit to let's say 3 or 5 people; it won't hurt (never seen that feature being abused) and especially many people believe it already works that way.


I have difficulty distinguishing the two phonetic symbols. Roads, rose; needs, knees... Do these words sound very different to native speakers? How should I pronounce them?

So I can pronounce friend just fine. But when you add an s to it how do you transition from the d sound to the s (/z/) sound? Do you just ignore the d altogether?


[Edit]:This question is asked to handle a specific design issue. Although it is mainly related to the post I am sharing below, it is not meant to generally differentiate between Filtering and Searching but to use the concept in practice. The answer below by @KK although good, it assumes a fact that when no data is displayed then the user is searching, when data is displayed then user is filtering. If that is a fact to draw conclusion upon, then the answer to my question = Filtering. [End of Edit]  In a web-based application, a page displays information in a table format (random data displayed in the table). The table could have hundreds of records. Two  ways are provided to filter/limit/refine/search the results in the table:  (1)- A single select drop-down list (Filter by Type) with the Types available (there are less than 10 types in the system). When the user selects a Type from the list, results will only be the records with the Type the user selected. So I know I am filtering here (I am providing the filter which in this case = Type). For example: If I select "Accounting" from the list, only records with the Type = Accounting will be displayed.  (2)- A text-box where the user is advised to enter either a Director name or a Year, and results are displayed based on the user's entry (see example below). If user enters "41" only, then the results will be every record that contains the number "41" under Director or Year columns. This text-box will only look at values under the Director and Year columns.    The irony is that I answered a question () thinking I have good enough knowledge in regard. However, I am still confused about it in this specific design.  So am I Filtering or Searching in the Text-box? Should the Placeholder (or if replaced by a Label) say "Filter by..." or "Search by..."?

From the view of the user (not from a technical view)- What are the main differences between searching and filtering data, in order to get specific results?  i.e.- in both cases the user is looking for specific data so why should  he care which method is used to find it?...  would you say these two methods are mostly the same (in the eyes of the user)?  If not- when would you use each?


I installed Windows 7 alongside Ubuntu 14.10 and hence I lost grub. I reinstalled grub using a liveCD and now the Ubuntu boot option only shows Windows 7 and 10s timer after which it'll boot into Windows 7. It doesn't show Ubuntu option. I tried repairing boot using boot-repair tool but no luck.  Here's the boot-repair pastebin:

I installed Ubuntu on a Dell XPS 13 laptop that had Windows 10 preinstalled on it. I installed it from a USB flash drive on a partition. When I boot my computer I can only boot into Windows 10 and Ubuntu is nowhere to be seen.  If I boot into my USB then I can see that Ubuntu is installed, but I can't get to it from the BIOS boot menu.


I replaced my Windows OS with Ubuntu. After a successful installation I can not find my other drives ( i.e. D, E, F, G ) and their contents in Ubuntu. Is it erased? I was not aware of that. Is there any way to get the contents back?  P.S. At the time of installation I clicked the "erase and replace windows", not "something else".

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.


this is my code..but I'm encountering an error of null pointer exception whenever I try to access private variables of "Category" class to "Product" class in the applyCoupon() method...  //main class      public class basicjava{          public static void main(String args[]){             Product product=new Product();             Category category=new Category();             category.setCategoryName("book");             product.applyCoupon();     }      }   //second class   public class Product {         private Category category;         Product(){          }          public Category getCategory() {             return category;         }          public void setCategory(Category category) {             this.category = category;         }          public void applyCoupon(){             if (category.getCategoryName()=="book") {                 System.out.println("book");             }             else {                 System.out.println("page");             }         }      }   //third class  public class Category {     private String categoryName;     Category(){      }      public String getCategoryName() {         return categoryName;     }      public void setCategoryName(String categoryName) {         this.categoryName = categoryName;     } }

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?


class Cardboard{     Short story = 200;     Cardboard go(Cardboard cb){         cb = null;         return cb;     }      public static void main(String args[]){         Cardboard c1 = new Cardboard();         Cardboard c2 = new Cardboard();         Cardboard c3 = c1.go(c2);         c1 = null;           } }   After go() is executed c2 should be pointing towards null, as implied by the method.This reference of c2 is passed to c3 variable, which again is pointing to null only thus c2's object must be available for garbage collection.

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


I'm currently fiddling around with some RPG mechanics and I'm trying to implement a solid way to handle items that have different on use effects.  Currently, I have a base class called "Item" that consists of things that all items have such as ID, name, description, quality etc. Then I have some subtype classes that extend "Item" such as "Weapon", "Armour", "Consumable", "Material" and "Quest". "Item" also implements an interface called "Usable" that has a Use function.  These subclasses share the exact same qualities. Such as all armour has an armour value, all weapons have an attack value etc so that I don't need a different class for each item but I want the use effects to differ. An example is that I have an item of type "Consumable" which when the use function is called, restores player health, a different consumable may do this again, but heal a greater amount. Another consumable may teleport the player to a specific location. These items are being stored in a JSon file and there may be a thousand or more different items and effects.  So, firstly, What would be an effective way to implement this behaviour? Secondly, if the vast majority of items have a use effect in each category but a few don't, should it still be structured like this?  Thanks.

This is specifically about the development and planning direction of the game development.  I'm creating a fairly basic RPG and am wondering about the approach that I should take. I've been trying to outline it all in a flow chart first, but want to see if this is a good way of going about it.  For example, I've created a class called "items", which then currently derives into "Weapons" "Armor" and "Potions". I then derive these classes further into specific types and I keep going and going, basically as specific as I want to get.  Before I get too deep into this (again, I'm still planning) - I just want to know if this is a good way of approaching this problem.


I think Area 51 is a site of Stack Exchange, so why does the score of Area 51 not show my score here?    But it is showing it here:

is in the list of SE sites of the new top-bar included. But since  it should be in my top 5 sites to be consistent.  BTW I don't get notified about new rep on Area51 as well.


Does the limit:   $$\lim_{n\to\infty}  \left (1+ \frac {1}{2^2}+ \frac {1}{3^3}+...+\frac {1}{n^n} \right)$$   admit a closed form?   I know only Riemann-Zeta function.I've just discovered this sum.

Earlier today, I was talking with my friend about some "cool" infinite series and the value they converge to like the Basel problem, Madhava-Leibniz formula for $\pi/4, \log 2$ and similar alternating series etc.  One series that popped into our discussion was $\sum\limits_{n=1}^{\infty} \frac{1}{n^n}$.  Proving the convergence of this series is trivial but finding the value to which converges has defied me so far. Mathematica says this series converges to $\approx 1.29129$.  I tried Googling about this series and found very little information about this series (which is actually surprising since the series looks cool enough to arise in some context).  We were joking that it should have something to do with $\pi,e,\phi,\gamma$ or at the least it must be a transcendental number :-).  My questions are:   What does this series converge to? Does this series arise in any context and are there interesting trivia to be known about this series?   I am actually slightly puzzled that I have not been able to find much about this series on the Internet. (At least my Google search did not yield any interesting results).


I've been having a problem recently (Chrome 34.0.1847.116 m, Win7) where I cannot highlight text in the question/answer being reviewed (the text acts like it is a background image), nor can I use the scroll bar on the side of the page to look further down (though I can use the arrow keys most of the time when the mouse stops working. The other day the arrow keys stopped working and I could only use pgup/pgdn). I can still click "close", "edit", etc, but nothing else on the page is responsive. Obviously this has never happened even once on any other site (nor anywhere else on stack overflow), or I wouldn't be asking about it here. If I close the review tab and go back to it, the problem gets temporarily fixed. Has anyone else experienced this?

Basically when reviewing a low quality post, if I choose to edit the item, I cannot move the cursor by clicking in the textarea. The keyboard is working fine, but any mouse interaction appears to be disabled.  The issue only appears if you review one item first, then the next item is loaded in. Editing this item will have disabled mouse input.  I haven't tested other review queues yet but will do so as soon as possible. This seems to only affect low-quality posts.  Browsers I've tested:  Broken   Chrome 33, Win 7 Chrome 34, Win 7 | OSX Mavericks Chrome 36, Win 7 Firefox 28, Win 7 Safari 8, Yosemite   Working   Safari 7 OSX Mavericks (Intermittent)


I have typed apt-get update && apt-get upgrade -y  And I am trying to install linux-headers on Kali-Linux 2016.1  0 upgraded, 0 newly installed, 0 to remove and 394 not upgraded  So I typed uname -r  And got this as a response  4.3.0-kali1-amd64  Then I type apt-get install -y linux-headers-$(uname -r)  then get this error  E: Unable to locate package linux-headers-4.3.0-kali1-amd-64 E: Couldn't find any package by glob 'linux-headers-4.3.0-kali1-amd64' E: Couldn't find any package by regex 'linux-headers-4.3.0-kali1-amd64'  Can anyone please help me, I have tried a lot of things and none of them work?

I am using a virtual machine to run Kali linux and when I run this command apt-get install -y dkms linux-headers-$(uname -r) it gives me this error:   E:Unable to locate package dkms E:Unable to lcoate package linux-headers-4.6.0-kali1-686-pae E:Couldn't find any package by glob 'linux-headers-4.6.0-kali1-686-pae' E:Couldn't find any package by regex 'linux-headers-4.6.0-kali1-686-pae'   The contents of the uname variable are:   4.6.0-kali1-686-pae   How can I fix this error, it is stopping me from following a tutorial. Any help is greatly appreciated :)


I'm trying to bridge two edge loops in Blender 2.8 to make a curved pipe. I was able to do this in 2.79 but I cannot get it work in 2.8.   After setting profile to 0. Setting it to -1 makes it look crumpled. Either way I cannot seem to make a nice arc.   Is there another way to bend a pipe?   Same settings as Robin Betts

I would like to smooth out this pipe. I know that I should have made it out of a curve. Is there any way to smooth the pipe?


I'm no math wizard, and this question however has been bothering me a lot. In my opinion, adequate information isn't present. But I need an expert opinion.    The boxes are all squares.

There is three square in a circle like the picture attached.   How can find radius of circle  ? I know that's not a hard problem,but I was away from geometry for years.  If possible give me hint or idea to start to solving.   Thanks in advance.   the smallest side is $6$ and medium square side is $6+6$ and big side is $6+6+6$ But I got stuck here and not to go over there ...


What is the limit ?  $$\displaystyle\lim_{n\to\infty}\frac{1}{n}[(n+1)(n+2)\dots(n+n)]^{\displaystyle\frac {1} {n}}$$  The given answer is $\displaystyle\frac{4}{e}$, but I don't know how to find it or which formula is applicable here.Please help.  Thanks for  help.

Evaluate $$\lim_{n \to \infty} \frac{1}{n}[(n +1)(n+2) \cdots (n+n)]^{\frac{1}{n}}$$  We can write as $\displaystyle\lim_{n \to \infty} \frac{1}{n}[(n +1)(n+2) \cdots (n+n)]^{\frac{1}{n}}$ $$= \lim_{n \to \infty}\left[\frac{(n +1)(n+2) \cdots (n+n)}{n^n}\right]^{\frac{1}{n}} = \lim_{n \to \infty}\left[(1+\frac{1}{n})(1+\frac{2}{n})\cdots (1+\frac{n}{n})\right]^{\frac{1}{n}}$$  I have used this result if $\{a_n\}$ is a sequence of positive term which is convergent to $l$ and $b_n = (a_1. a_2 . \cdots a_n)^{1/n}$ ,thhen $b_n$ converges to $l$  here $a_n = 2$, but i think it is not right,how to use this result in this question. Give me hint how to proceed . Thank you


I'm trying to simulate shadows for a 2D top-down RPG (in Python), but I can't think of the best way to do this  So far I've tried making copies of the original game entities and turning all opaque pixels black (which is a bit slow), then rotating them around the bottom of the original image... but i couldn't quite get that approach to work.  So how can I simulate this effect?

I want to have 2D lighting that can be blocked by in-game objects. My game has a top-down view and all game objects are described by rectangles.  Let's say I have a 10x10 world and I place a light at 1x1 and walls all around that light. I want to be able to see the light source at 1x1, but not anywhere else, because it's blocked by the walls.  I've heard of casting light rays works, but how does that really work?


If $S$ is a finite set, show that $|P(S)| = 2^{|S|}$.  So I know that $|P(S)|$ means the number of elements in the power set of $S$, but I don't understand the relation between the power set and $2^{|S|}$.  I tried doing:  Suppose $|S|=n$, then $|P(S)|$ = the union of each subset of $S$. Then $|P(S)|$ is the set $\{x_1, x_2, x_3, .... x_n\}$. But I'm not even sure if I'm thinking about this right.  Any help would be awesome!

Please help with this question. Show that for a finite set $A$ of cardinality $n$, the cardinality of $P(A)$ is $2^n$, where $P(A)$ is the power set of $A$. Thank you in advance for any help that is given.


I am using blender 2.79b. I cannot see the image output even after i load an image. I used the properties panel to load the image. Under the 'Background Images' tab. I added an image file(i tried both ".png" & ".jpg" formats). Please guide me.

I try to set up an image as background for a basic blender tutorial, but it isn't visible.  This is the image I try to have as background:


I have bought a new samsung s4.  I try to change the OS settings to be in hebrew.  I remembered how to do it from another s4 my sister has.  Went to settings --> Languages and input ---> but there was no "hebrew" to choose.  Then I have tried "more locale 2" but it should solve some other issue, no?  anyhow either i did it wrong or it didn't help as well.

The aftermarket ROM I use seems to have the language list parred down to just a couple selections, probably to save space.  I would like to add a language back into the system. I can already set the locale using programs such as  so that applications with my language support start with the right locale code, however that doesn't add missing system languages. Having the system in another language would be nice, but the main thing is getting the dictionary files for the keyboard auto-complete. How does one go about adding the language support files for an input language to a system or ROM?  I can access other ROM's or the AOSP project to rip things out, but I don't know where to start. What files do I need and what modifications need to be made? Is there an easy way to do this with say a language-pack or is it hackery all the way?  My ROM is fully rooted and I have adb access if necessary. It's Android 2.3.7 () and I'm using the stock Android keyboard. The language I want is Turkish, although unless somebody has a download to point me to it's mostly the process I'm looking for here.


My question is about the computation of the Jordan normal form. Let $K$ be field. Let $A \in K^{n \times n}$ be a matrix, that characteristic polynomial splits into linear factors over $K$. I've learned that the number of Jordan boxes of size $j$ for an eigenvalue $\lambda$ of $A$ is given by $$c_j(\lambda, A):=2\dim \ker (A - \lambda I)^j - \dim \ker (A - \lambda I)^{j+1} - \dim \ker (A - \lambda I)^{j-1}.$$ I want to prove this fact.  Let $J$ be the Jordan normal of $A$. I have already shown that $$c_j(\lambda, J)=c_j (\lambda, A).$$ What is left to show is that the number of Jordan boxes of size $j$ for the eigenvalue $\lambda$ of $J$ can be computed by $$2\dim \ker (J - \lambda I)^j - \dim \ker (J - \lambda I)^{j+1} - \dim \ker (J - \lambda I)^{j-1}.$$ Thanks.

Suppose I have an eigenvalue $\lambda$, now I want to determine the number of Jordan blocks corresponding to that eigenvalue, as well as size of each block. I know that:  number of blocks is equal to the number of eigenvectors there are $\dim \ker (A - \lambda I)^k - \dim \ker (A - \lambda I)^{k-1}$ blocks of size at least $k$ Why exactly are those statements true. Could someone provide me with a proof or at least some reasoning behind this?


Can one disable and remove Wifi Sense completely?  Perhaps by disabling a service, removing system files, or by registry editing?  I found options and registry keys to stop Microsoft from sharing your Wifi passwords with other people, but I want to disable Wifi Sense completely, so that not even Microsoft gets my Wifi data.    How can I do that?    Is Wifi Sense running as a dedicated process or service on my system? Are there more secret registry entries?  This other question () is related, but I want to go a step farther and actually remove the Wifi Sense functionality from my system so that it never has the chance to share any networks.   And yes, I know that you can add _optout to you wifi SSID to disallow sharing of your own wifi's password. But first of all I cannot change my SSID and secondly I'm not only using my own Wifi and I certainly don't want to share other peoples password with Microsoft, can be highly illegal in some circumstances (at work for example).   EDIT: From what I understand, wcmsvc is the service responsible for Wifi Sense, but it's also responsible for the Wifi core components itself. So disabling would probably kill Wifi altogether. :/ Another thing I found out is that Wifi Sense seems to store it's registry entries in this key: HKLM\SOFTWARE\Microsoft\wcmsvc\wifinetworkmanager\ Any idea what all the keys in it do? For example: HKLM\SOFTWARE\Microsoft\wcmsvc\wifinetworkmanager\crowdsrcplugin\EnableWiFiCrowdsourcing  Screenshot showing there is no complete disable option:

In recent release of Windows 10 we could see a new feature named wifi sense, which raised the following security threat as per this  :     This brilliant new feature, which Microsoft has dubbed Wi-Fi Sense,   doesn’t share your WiFi network password per se — it shares an   encrypted version of that password. But it does allow anyone in your   Skype or Outlook or Hotmail contacts lists to waltz onto your Wi-Fi   network — should they ever wander within range of it or visit your   home (or hop onto it secretly from hundreds of yards away with a good   ‘ole antenna!).   As per faq :     For networks you choose to share access to, the password is sent over   an encrypted connection and stored in an encrypted file on a Microsoft   server, and then sent over a secure connection to your contacts’ phone   if they use Wi-Fi Sense and they’re in range of the Wi-Fi network you   shared   From  :     First, a bit of anti-scaremongering. Despite what you may have read   elsewhere, you should not be mortally afraid of Wi-Fi Sense. By   default, it will not share Wi-Fi passwords with anyone else. For every   network you join, you’ll be asked if you want to share it with your   friends/social network   From the above excerpts it's unclear whether Windows 10 shares wifi details with  my contacts; So my questions were few :  Does it really shares WiFi details with my contacts since many articles states it's shared & it's not shared.  If it's shared how can I prevent it?


I am using Debian 8 Jessie with Gnome 3. I can't move the windows of the bottom panel. I just want to rearranged them but it doesn't work. I click one of them and try to move it but nothing happend.

I have centos 7.1. At bottom panel opened windows (running applications) are represented (ex: openoffice, thunrderbird, terminal). Question one - How can I change the order of these opened windows (ex:terminal,openoffice, thunrderbird) as in centos 6 I did drag and drop but here I can't?   The strange thing is that I've noticed that their order suddenly changes when I lock the system and log in again. Question two - how can it be explained?


I program the wrong email on my I cloud account and when I go to fixing it I can't fix it because the email doesn't exist .

I never changed my student email account to which all app purchases have been made. I just upgraded to iOS 5, and it requires to authenticate the iCloud, by verifying an email sent to the now defunct email address. The problem is that I can't even change my email adress, because the system wants to verify my iCloud account first. It's a circular problem!  Can't change email because I haven't verified iCloud, and I can't verify iCloud because my old email is now defunct.  What can I do??


I am building a Chrome extension that works with a conversion optimization tool (visual website optimizer or VWO to be precise). On websites that use VWO the tool shows information like running experiments, the data needed is retrieved from the DOM.   Now I want to implement a feature that will list goals fired on a page. A goal is a user defined event such as page view, clicks on elements etc. When a goal is fired VWO sends a c.gif call to their server, this call contains the information I need.   I can see the c.gif call in the Chrome network console so I assume my extension should somehow be able to do the same. But how this is achieved I can't figure out. And help here would be greatly appreciated :)   I found some help here:  and here:  but I couldn't get my code to register the Ajax event (or any Ajax event).   My extension is designed like this: A default pop-up.html with a pop-up.js that on load fetches the background script. The background script asks the content script for the DOM data. When the data is retrieved it is send back via the background to the popup.js  I hope someone can help me with this. If possible I would prefer not to use jQuery (or another library) unless they make matters much easier. (that's why I tagged jQuery)

I would like to capture the contents of AJAX requests using Greasemonkey.  Does anybody know how to do this?


The problem is following: Suddenly the edit text mouse cursor disappear in guest OS text editors and text fields. Instead of Text Select cursor only few pixels are visible.  Issue related to windows guests (I had this on Win7-64 and Win2016-64) and windows host (win10-64). Update of vbox, guest additions, extension packs - did not help. Any ideas how to fix? Vbox version so far: 5.2.20 r125813 (Qt5.6.2) GA and EP enabled.

I am using latest version of VirtualBox (VirtualBox 4.3.6 for Windows hosts) and after installing any OS and clicking inside of it mouse disappear. It is not visible until I press right CRTL. Anyone know what can cause this problem. I have also installed extension pack.


When using my Android device at my desk, is it better to (from a battery health point of view) detach a charger as soon as the device gets fully charged, or is it ok to keep it on the charger? I like to use it at my desk while it is plugged in so that it is fully charged when I walk away, is this ok?

I usually disconnect my cellphone from the charger some time after it's fully charged because I'm afraid the battery could lose capacity over time if I don't. However, I believe modern electronics should be able to handle this kind of scenario and automatically stop charging the battery once it's full. Does this apply to modern Android phones? Or do I need to continue disconnecting it all the time?


What exactly is the difference between the Frame Dropping and AV-Sync options? I understand that they both drop frames in order to make the playback closer to real-time in the 3D view, but how does AV-sync make it more synced to the sound than frame dropping, if they're both just dropping frames to get the correct frame rate? Is there any time when I should use frame dropping instead of AV-Sync, if they both get the correct frame rate?

How do the AV-sync, Frame Dropping and No Sync options in Timeline work when working with audio and video?


I have the following class:  public class EnumContainer{      private Class<?> enumClass;     //GET, SET      public EnumContainer(Class<?> clazz){         this.enumClass = clazz;     }      public boolean tryCast(String value){         //Here I should try to cast the String to the Enum by enumClass field          //return true if cast was successfull         //false otherwise     } }   Is it even possible in Java to perform such casting?

Say I have an enum which is just public enum Blah {     A, B, C, D }  and I would like to find the enum value of a string, for example "A" which would be Blah.A. How would it be possible to do this? Is the  the method I need? If so, how would I use this?


I have Drupal 7.43 installed on my hosting account, and I am using phpmailer to send all emails. It is giving the following error:       Type phpmailer   Date Monday, March 21, 2016 - 15:39   User shyamzawar   Location    Message SMTP error: Could not connect to SMTP host.       Subject: PHPMailer test e-mail      Body:        Your site is properly configured to send e-mails using the PHPMailer   library.      Message:     array (        'id' => 'phpmailer_test', 'module' => 'phpmailer',      'key' => 'test', 'to' => 'shyamzawar@ymail.com',        'from' => 'shyam007zawar@gmail.com', 'language' => NULL, 'send' => true,        'headers' => array(          'X-Mailer' => 'Drupal',        ),      )       Severity error

When my web form is filled and submitted, I get redirected to a page that says:     Thank you for submitting.   but theres a red warning box there that says:     Unable to send e-mail. Contact the site administrator if the problem persists.   I think its the SMTP server, but I don't know how to fix that.


I have been sent a 3-fold (4 facet, double-sided so 8 page per sheet) leaflet as a PDF. I'd like to print it but none of the Okular print options offer sticking 4 sides next to each other. It's always a grid.  The PDF is currently presented as one long and thin portrait page per page. I would like to merge these so that the pages are combined in sets of 4 side-by side, leaving a landscape document that I can easily send to the printer.  Just to clarify, there are a lot of questions about merging multiple documents into one. I have no interest in that. I have one document whose pages I wish to merge down.

I want to combine two pages in pdf file into single page.  Consider I have a pdf file in which there are two pages, now I want to combine two pages into (single) one, No-matter for (how-long) page-size!  How to do that?  Note: This question is not about combine two pdf files or merging pdf files or adding pages in pdf files.  Also visit .


Here is the problem: One hundred people line up to board an airplane. Each has a boarding pass with assigned seat. However, the first person to board has lost his boarding pass and takes a random seat. After that, each person takes the assigned seat if it is unoccupied, and one of unoccupied seats at random otherwise. What is the probability that the last person to board gets to sit in his assigned seat?  I came up with a solution but I could not find it anywhere on the internet, so I would appreciate if someone could check the legitimacy of my work:  Let's say $p(x_{n})$ is the probability that the $n^{th}$ person to board the plane takes the seat of the last person to board the plane.   Obviously the first person to board has a 1 in 100 chance of randomly picking the last person's seat, so $p(x_{1})$ = $\frac{1}{100}$.  The second person to board the plane will sit in their assigned seat unless the first person takes their seat. There is a 1 in 100 chance that the second person's seat got taken. Assuming that the second person's seat got taken, there is a 1 in 99 chance that the second person takes the last person's seat, so $p(x_{2})$ = $\frac{p(x_{1})}{99}$.  Following this logical progression, $p(x_{3})$ = $\frac{p(x_{1})+p(x_{2})}{98}$, $p(x_{3})$ = $\frac{p(x_{1})+p(x_{2})+p(x_{3})}{97}$, etc.  We can define a new variable $p({y_n})$ = $\sum_{i = 1}^{n}p({x_n})$.  It doesn't take too much work to find that $p({y_n})$ = $p({y_{n-1}})(1+\frac{1}{101-n})$  Solving this recurrence relation, we get $p({y_n})$ = $\frac{1}{101-n}$  Plugging in $n=99$, we see that the probability that one of the first 99 takes the last person's seat $p({y_{99}})$ = $\frac{1}{2}$. Therefore the probability that the last person to board sits in their assigned seat is $\frac{1}{2}$.  I am aware that this is the correct solution. However, I'm not sure that my work is logically sound. Any validation (or rejection) of my work would be appreciated.

This is a neat little problem that I was discussing today with my lab group out at lunch. Not particularly difficult but interesting implications nonetheless  Imagine there are a 100 people in line to board a plane that seats 100. The first person in line realizes he lost his boarding pass so when he boards he decides to take a random seat instead. Every person that boards the plane after him will either take their "proper" seat, or if that seat is taken, a random seat instead.  Question: What is the probability that the last person that boards will end up in his/her proper seat.  Moreover, and this is the part I'm still pondering about. Can you think of a physical system that would follow this combinatorial statistics? Maybe a spin wave function in a crystal etc...


I fully understand why there's a filter that requests one to submit edits of at least 6 characters. But either is there, or could there be, some form of "yes, I'm sure" override? Barring that, what should one do when an answer really does need a one word added to it - because it won't compile as written, as it's missing a piece of required syntax which happens to be a two-character word, but is otherwise helpful - and doesn't need anything else? It seems entirely backwards that one should be required to make some other unnecessary edit, that would confuse anyone looking at a diff?   Yes, I could just change a word to another word that means the same thing, or add some invisible whitespace, but is that really what I should be doing?

I just wanted to fix a code sample which had a single character missing. However I can't do this because the minimum edit is 6 characters.  Can we make the checker smarter by allowing single character fixes for code blocks?


/Date(1482048633480)/ is the result when appending() the DateTime value into HTML.   $("#Date").append($('<div> '+ data.DateTimeFromController+' </div>'))   How to read data.DateTimeFromController in MM/DD/YYYY Hour/Min/Sec AM/PM format?

I'm taking my first crack at  with jQuery. I'm getting my data onto my page, but I'm having some trouble with the JSON data that is returned for Date data types. Basically, I'm getting a string back that looks like this:  /Date(1224043200000)/   From someone totally new to JSON - How do I format this to a short date format? Should this be handled somewhere in the jQuery code? I've tried the jQuery.UI.datepicker plugin using $.datepicker.formatDate() without any success.  FYI: Here's the solution I came up with using a combination of the answers here:  function getMismatch(id) {   $.getJSON("Main.aspx?Callback=GetMismatch",     { MismatchId: id },      function (result) {       $("#AuthMerchId").text(result.AuthorizationMerchantId);       $("#SttlMerchId").text(result.SettlementMerchantId);       $("#CreateDate").text(formatJSONDate(Date(result.AppendDts)));       $("#ExpireDate").text(formatJSONDate(Date(result.ExpiresDts)));       $("#LastUpdate").text(formatJSONDate(Date(result.LastUpdateDts)));       $("#LastUpdatedBy").text(result.LastUpdateNt);       $("#ProcessIn").text(result.ProcessIn);     }   );    return false; }  function formatJSONDate(jsonDate) {   var newDate = dateFormat(jsonDate, "mm/dd/yyyy");   return newDate; }   This solution got my object from the callback method and displayed the dates on the page properly using the date format library.


I know this might be a dupe of  or  or maybe  and I am sure there will be others to find, but this issue still is not resolved (and those posts are either old or ). Or maybe it was resolved but someone () has broken it again. Again I am not here to  anyone.  I just want to point out that the issue still is present in chat and it is a pretty annoying issue (yes I am annoyed fast).  The problem is that sometimes the flag badge in chat gets "stuck". Meaning it will tell you (in a very convincing tone) that there is some flag to handle, but when clicking it you will be greeted by the message there aren't any flags to handle.  It has been like this for a while so I cannot really tell when it started doing this.

When someone flags a message in chat all 10k+ users in chat get a little blue bubble to vote on. It shows up in the upper left hand corner of your gravatar (which is in the bottom left of the page).  When someone flags a message and it shows up, if I wait for a second to click on it, and then click on it, and it has already been handled, it shows the message  "There are no flags to display."  In the past, after showing this message, the blue (1) would disappear. However, lately it has not been going away and requires a page refresh in order to remove. Can this be fixed?  This issue is addressed here:  from September 12th 2012. But since it is still occurring 10 months later, I believe the cause is different.


PROBLEM SOLVED...THANKS PGMATH FOR THE HELP.  I'm brand new to using Blender, and I'm trying to teach myself some basics to use in conjunction with 3D printing.  To do that I'm trying to 3D print a plate with a logo on it.  However, I'm having an issue with one single letter in the logo showing up as "negative" space after slicing the model in the 3D print software (Repetier-Host).  I'm lost on why this is happening or where in the process I'm messing up?  The only thing I notice that is strange is that the shadowing for the letter in Blender looks a little different from the surrounding parts (and its more noticeable when input into the print software). In Blender and Repetier-Host that specific letter still looks extruded, even though the shadowing is strange (less shadowing, i guess), and its not until the model gets sliced does it become "negative".  And it's not like each letter in the logo was uploaded separately.  The entire logo was a single PNG file originally and converted to a SVG file through Inkscape. So why this specific letter is behaving differently is very confusing?  And FYI...when making the file Blender file I appended the logo (previously extruded) with a plate part to create the file full part.  Anybody have any thoughts or experiences with something like this?  Thanks.

While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered.   The blackening effect is visible in the viewport too.  How can I solve this problem?


#include<iostream>  using namespace std; class Base {   public:     virtual void show() {       cout << " Amphisoft \n";     } }; class Derived: public Base {   public: void show() {     cout << "E-box\n";   } }; int main(void) {   Base * bp = new Derived; //  cout<<*bp;   bp -> show();   Base br = *bp;//should'nt it return me E-box , why amphisoft   br.show();   return 0; }   Why is the output coming out to Be Ebox Amphisoft . Why not Ebox Ebox? I tried to putting this : Base &br= *bp . And it gives me Ebox Ebox . Here address of the base object is being put equal to address of the new Derived object . But i dont understand what this statement of code is doing : Base br=*bp

Someone mentioned it in the IRC as the slicing problem.


For a positive integer $n$ let $S(n) = \sum_{i=1}^{2^{n}-1} \frac 1i = 1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+ \cdots +\frac{1}{2^n-1}.$      Then which of the following are true.         (a) $S(100)\leq 100$.   (b) $S(100)>100$.   (c) $S(200)\leq 100$.   (d) $S(200)>100$.      My attempt   For the upper bound  $$\begin{align} S(n) &= 1 + \left( \frac 12 + \frac 13 \right) + \left( \frac 14 + \frac 15 + \frac 16 + \frac 17 \right) + \cdots + \left( \frac 1{2^{n-1}} + \frac 1{2^{n-1}+1} + \cdots + \frac 1{2^n-1} \right) \\ &< 1 + \left( \frac 12 + \frac 12 \right) + \left( \frac 14 + \frac 14 + \frac 14 + \frac 14 \right) + \cdots + \left( \frac 1{2^{n-1}} + \frac 1{2^{n-1}} + \cdots + \frac 1{2^{n-1}} \right) \\ &= \underbrace{1 + 1 + \cdots + 1}_{n\text{ times}} \\ &= n. \end{align}$$  So we get $S(n) < n$ (for $n > 1$), and in particular $S(100) < 100$.   Now I did not understand how to calculate a lower bound, or if there is any other method by which we can solve this.

$\dfrac{n}{2} \le \dfrac{1}{1}+\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2^n - 1} \le n $  I've Tried for hours but didn't got any striking idea. I don't have any efforts to show rather than induction. Please Try If you 've non-inductive proof.


Suppose I want to use a beamer presentation with lots of piecewise slides e.g., <1->, <2->, etc. During preparation, want to toggle them all off so that the output is compact and easier to edit. Then for presentation, I'm hoping to toggle them all on by changing one line of code for presentation so that the output is expanded (i.e., one slide for each piecewise part).  \documentclass{beamer}  \begin{document}  \begin{frame} \begin{align*}     \onslide<1->{a &= b \\}     \onslide<2->{b &= c \\}     \onslide<3>{\Rightarrow \quad      a &= c} \end{align*} \end{frame}  \end{document}

Say I made a beamer presentation and I want to print it out.  Is there a nice way to make beamer ignore the pauses so that I don't get lots of pages with duplicate information?  Of course there are some things one could do with find & replace, but I would prefer a more sophisticated solution if such exists.


I know the isomorphism is $F: G \rightarrow \text{Inn}(G)$ defined as $F(a) = \phi_a$ where $\phi_a(x) = axa^{-1}$ but I'm not sure how to use the assumption (that $G$ has trivial center) to prove injectivity and surjectivity. I got as far as showing it was a homomorphism but just having trouble with the last part. This is what I have for the proof of a bijection:   Suppose $G$ is a group such that $Z(G) = \{e\}$ and let $F : G \rightarrow \text{Inn}(G)$ be defined by $F(a) = \phi_a$. I claim that $F$ is injective by proving that if $F(a) = F(b)$, then $a=b$ (i.e. that $F(a)$ and $F(b)$ are the same function). Suppose for some $a,b,x \in G$ with $x \neq e$ that $F(a)(x) = F(b)(x) \implies \phi_a(x) = \phi_b(x) \implies axa^{-1} = bxb^{-1} \implies ax = bxb^{-1} a \implies x = a^{-1} bxb^{-1} a \implies a^{-1} b = e \implies b = a$.  Do I need to make any other assumptions on my choice of $x$ (should I even assume $x \neq e$?) or $a$ and $b$?  We have not discussed quotient groups or kernel and I would like to prove it by showing that $F$ is a bijective homomorphism.

I've seen other posts () about the topic of $\operatorname{Inn}(G) \simeq G/Z(G)$, but what I want to ask is a detail. When we ensure that $\operatorname{Inn}(G) \simeq G/Z(G)$, we want to say that there exists some isomorphism $F$ such that:  $$F: G/Z(G) \rightarrow \operatorname{Inn}(G), \quad F(gz) = \tau_g$$  where $g \in G, z \in Z(G)$ and $\tau_g(h) = ghg^{-1}$ for all $h \in G$  But is this $F$ really an isomorphism? I'm not pretty sure due to there is not ONE $\tau_g$ for ONE $gz$, what we have is a total of $|Z(G)| = \text{order  of }Z(G)$ elements of the form $gz$ for just ONE $\tau_g$ due to $\tau_g = \tau_{gz}$ if $z \in Z(G)$


Let $A,B$ two square-real-positive matrices. Prove that $\det (A+B) > \max(\det A , \det B)$  So I found this solution:   Basically, if $A=I_n$ and $B$ is diagonal then the proof is immediate.    Now, I know that if $M$ is positive-symmetric then:     $M$ is conjugate to $I_n$. $M$ is conjugate to $\text{Diag}(c_1,\ldots,c_n)$ where $c_i > 0$.   but as far as I understand it doesn't have to be the same $P$. Anyhow, how do I utilize it in order to prove the inequality?   Thanks.

Let $A,B\in M_{n}(\mathbb{R})$ be symmetric, with $A>0$ and $B>0$.  I need to prove that $\det (A+B)>\max (\det(A), \det(B))$.  I want to use Sylvester theorem of having a matrix $D$ so that $D=\operatorname{diag}(1,1,\ldots, 1,-1,-1, \ldots-1,0,0,\ldots,0)$.  Do I need to use it? How do I use it here?  Thank you.


I accidentally applied a subdivision surface modifier, but I don't want that. I tried to undo it, but that is not working. Is there any other way to do this?

I am wondering if there is a modifier or tool that will essentially undo a subsurf or subdivide command.


Is true that the set of the Borelians in $\mathbb{R}$ has the same cardinality of $\mathbb{R}$? I need of the Continuum Hypothesis for to prove this?

It seems it's well known that if a sigma algebra is generated by countably many sets, then the cardinality of it is either finite or $c$ (the cardinality of continuum). But it seems hard to prove it, and actually hard to find a proof of it. Can anyone help me out?


I'm watching a tutorial on how to make Minecraft animations, and one step was to click on the replace a image button but it wouldn't let me.    Why is this option grayed out?

The image replacement button is blank after I've tried to replace the skin. When I tried to experiment by going into open new image, I've replaced it. I reversed it, but still can't find a solution after going on forums. Anyone know the solution or can back me up on this?


Consider the following sentence from  (a review of an episode from the TV show "How I Met Your Mother").  "The focus on Robin really aloud her character to get the kind of attention she has been missing for many a season."  Clearly, "aloud" should be "allowed". So, the writer has substituted one word with another that sounds the same when spoken, but is spelled differently and has a different meaning. What kind of spelling mistake do this call this in English?

What is the term for words that sound alike but have different spellings and meanings? For example, there and their.


I'm new to Linux and I have only used Windows so far (Currently: windows 8). But for a Bachelor Project at my university, I was advised to use Linux in combination with computations in statistical physics. I want to have a dual-boot Windows 8 and Linux.  Before installing, I read a lot of warnings and tips. I followed them (disabling Secure Boot in Windows 8, disabling Fast Boot). Then I made a partition to use for Linux Mint 17.2 Mate, and a swap partition. I installed it, and everything worked fine. But when turning on my computer, the grub screen didn't appear. After a day's work, I had installed Xubuntu instead of Mint and did a few Boot Repairs, and disabled the 'Secure boot' option in the Boot Repair Advanced options. After that, I could use Xubuntu without problems, also after rebooting. But I liked Mint better, so yesterday I tried to install Mint the same way as I did Xubuntu. But at the 'installing the grub2 package', the installation aborted with the error:     the grub-efi-amd64-signed package failed to install into /target/.   My guess is that I have made a mistake in the location of the bootloader, before the installation process. I installed (and later removed) Xubuntu, and with Xubuntu I installed the bootloader in /dev/sda2, where also the Windows boot manager is located. Before that, when installing Xubuntu another time, I installed the bootloader in a separate /boot partition /dev/sda8. Finally, another time I also installed the bootloader in /dev/sda. It was really a trial-and-error fixing the problem that no grub screen appeared at the beginning.  My guess is that now, those bootloaders that I've installed with Xubuntu on sda, sda2 and sda8 cause problems for the grub2 package with Mint to install.  I've already looked at many pages about the same issue, but none worked. I have a Internet connection and the 'extra 64' is present (see ).  What can I do? Any tips from experienced users? Or should I try another distro? Thanks in advance! Greetings from Holland.

I am installing Ubuntu 16.04 in an Intel NUC computer with UEFI enabled. I am using an SSD from another computer. During the installation I chose Erase the disk and make a new full install  At the end of the process I see:  grub-efi-amd64-signed failed installation /target/ Ubuntu 16.04    And the system does not boot.  I tried to use boot-repair but apparently it does not solve the problem.


Today I downvoted an answer so it went from 0 to -1  But I realised it was by mistake so I upvoted the same answer again but this time the value went up to +1.  I was expecting this to be zero.  I have attached the image.    EDIT  When I refreshed the page it came back to 0 again.

I have first downvoted an answer. Then, I decided to leave it the way it was before, meaning to undo my downvote just like it never existed, so I upvote to remove my downvote. Suprise! SO seems to consider it as two upvotes!  Let's say I have an answer with -3, then I decide to downvote it making it -4. After deeper thoughts, I prefer to remove my downvote to let it the way it was before I downvoted, meaning -3, but SO makes it -2 automatically!     Wouldn't it be supposed -3, and not -2? If someone else would have upvoted, it would have made it an upvote +1, not a +2!   Am I missing something here?  In fact, is there a way to tell SO that I only wish to undo my downvote, and not upvote the answer? I may understand why it does behave this way. I only wish to undo my downvote, though.


I am writing a document where I am the editor with (potential) many different authors. I was hoping there would be an \editor{...} command, that would complement the \author{...} command, but have yet to find anything.  I would like the editor to be mentioned on the title page of the document, probably under the title followed (on a new line) by the contributing authors.  What have you done to specify the editor of a document in addition to the authors?  I'm not necessarily looking for a package. If there is one, I'm happy to investigate it. If not, I'm equally happy to find "best practices" for specifying the editor of a document.

The standard titlepage is quite simple. I am looking for a very  and need help customizing my title page.  It should match the  classicthesis doctoral thesis template  Below a minimal working example:   \documentclass[12pt,a4paper,footinclude=true,twoside,headinclude=true]{scrbook} \XeTeXinputencoding iso-8859-1 \usepackage[marginparsep=8pt,left=3.5cm,right=3.5cm,top=3cm,bottom=3cm]{geometry}  \usepackage[parts,pdfspacing,dottedtoc]{classicthesis}    \frontmatter  \begin{document}     \pagestyle{scrheadings}        %this is the place to set up my cover sheet.       %*******************************************************      % Abstract     %*******************************************************    %\renewcommand{\abstractname}{Abstract}    \pdfbookmark[1]{Résumé}{Résumé}   \begingroup    \let\clearpage\relax    \let\cleardoublepage\relax    \let\cleardoublepage\relax       \chapter{Résumé}     Résumé de la thèse en français\dots      \vfill      \chapter*{Summary}   Résumé de la thèse en anglais\dots    \endgroup             \vfill     \end{document}


Today I had an interview where I was asked to write a program which takes a Binary Tree and returns true if it is also a Binary Search Tree otherwise false.  My Approach1: Perform an in-order traversal and store the elements in O(n) time. Now scan through the array/list of elements and check if element at ith index is greater than element at (i+1)th index. If such a condition is encountered, return false and break out of the loop. (This takes O(n) time). At the end return true.  But this gentleman wanted me to provide an efficient solution. I tried but I was unsuccessful, because to find if it is a BST I have to check each node.  Moreover he was pointing me to think over recursion.  My Approach 2: A BT is a BST if for any node N N->left is < N and N->right > N , and the in-order successor of left node of N is less than N and the in-order successor of right node of N is greater than N and the left and right subtrees are BSTs.  But this is going to be complicated and running time doesn't seem to be good. Please help if you know any optimal solution.

I read on here of an exercise in interviews known as validating a binary search tree.  How exactly does this work? What would one be looking for in validating a binary search tree? I have written a basic search tree, but never heard of this concept.


I'm new to Java and I can't figure out how to solve this problem. Whenever I try to run the program, after putting in a number for the "please enter 5 digit number" entry, the program goes directly to the else statement: "ERROR: Please enter a D, W, B, or X"  Here's the entire code:  import java.util.Scanner;    // needed to use Scanner for input  public class SeminoleBank_A {  public static void main(String[] args) {    //Create Scanner object   Scanner input = new Scanner(System.in);    //Declare and initialize   int deposit, withdrawal;   int balance = 0;   int number;   String menuChoice = "";    //Display welcome message “Seminole Bank”   System.out.println("\n********************************************************");   System.out.println("               Welcome to Seminole Bank!                   ");   System.out.println("********************************************************");    //Ask user to enter 5-digit Account Number   System.out.print("Please enter your 5-digit Seminole Account Number: ");    //Read user's Account Number   number = input.nextInt();    //Display "Thank You"   System.out.println("Thank you!!");    //Prompt user for year born   System.out.print("Enter D for deposit, W for withdrawal, B for balance, X to exit the menu: ");    // Read user's menu choice   System.out.println(menuChoice.toUpperCase() );    while (menuChoice != "X") {         if (menuChoice == "D"){            System.out.print("Enter the amount of the deposit: ");           deposit = input.nextInt();           System.out.printf("Account Number: " + number + "has a current balance of %.2f $: " + (balance + deposit));         }//end of if         else if (menuChoice == "W"){            System.out.print("Enter the amount of the withdrawal: ");           withdrawal = input.nextInt();           System.out.printf("Account Number: " + number + "has a current balance of %.2f $: " + (balance + withdrawal));         }//end of else if         else if (menuChoice == "B"){            System.out.printf("Account Number: " + number + "has a current balance of %.2f $: " + balance);         }//end of else if         else {          System.out.println("ERROR: Please enter a D, W, B, or X: ");         }//end of else       }//end of while  System.out.println("Thank you for being a loyal Seminole Bank customer!");  }//end of main  }//end of class   Any help would be greatly appreciated.

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


I am using Conky to display a lot of information of my system. I managed to display the load percentage per core. But I do not know how to display the clock frequency of each core. What I have now is:  ${font sans-serif:bold:size=8}PROCESSORS ${hr 2}${font} CPU1: ${cpu cpu1}% $alignr ${freq} MHz $alignr ${cpubar cpu1 8,60} CPU2: ${cpu cpu2}% $alignr ${freq} MHz $alignr ${cpubar cpu2 8,60} CPU3: ${cpu cpu3}% $alignr ${freq} MHz $alignr ${cpubar cpu3 8,60} CPU4: ${cpu cpu4}% $alignr ${freq} MHz $alignr ${cpubar cpu4 8,60} CPU5: ${cpu cpu5}% $alignr ${freq} MHz $alignr ${cpubar cpu5 8,60} CPU6: ${cpu cpu6}% $alignr ${freq} MHz $alignr ${cpubar cpu6 8,60} CPU7: ${cpu cpu7}% $alignr ${freq} MHz $alignr ${cpubar cpu7 8,60} CPU8: ${cpu cpu8}% $alignr ${freq} MHz $alignr ${cpubar cpu8 8,60}   But this only gives me the global clock frequency and not the individual clock frequency per core. Does someone know how to get the individual clock frequency per core?  System information   Linux Mint 13 KDE, 64 bit (based on Ubuntu 12.04) Intel i7-2670QM (quad core with multithreading)

Is there any way to check at which clock speed my processor is running?  I have already tried cat /proc/cpuinfo but the clock speed I'm running isn't showing. I know Ubuntu 12.04 (Precise Pangolin) requires 700 MHz and VGA, but will an AMD Mobile Sempron work?


If i have less contents on the page then the footer stays on the middle of the page instead of at the bottom. I just want the footer will stay always at the bottom of the page after all the contents of the page. I tried different ways and found few solutions in stack but none of them are working as per my need. Most of the posts are 3/4 years of old. So, I'm wondering if anyone has any effective solutions that works fine. I'm using asp.net.I'm not good at css so may be I'm doing something wrong. My page format is like this-                     <form>

                     <ucl:headercontrol />                     <asp:updatePanel>                     </asp:updatePanel>

xxxxx

         </form>         This is just my page skeleton. I would appreciate if any can give me any idea.

I have the following code for my masterpage:  <%@ Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %> <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">        <title>Masterpage</title>     <asp:ContentPlaceHolder id="head" runat="server">     </asp:ContentPlaceHolder>       <form id="main" runat="server" style="position:relative">
         <asp:ContentPlaceHolder id="MainContent" runat="server">         </asp:ContentPlaceHolder>
     </form>
     <form id="footer" style="position:relative">
         Footer content
         </form>     My problem is that when the MainContent isn't filling up the page the footer is not at the bottom of the page. Is there a way to force the footer to stay on the bottom of the page if the main content isn't pushing it all the way down? When the main content is "big" enough it pushes the footer down with the content and displays on the bottom when scrolling down, but not if it is to small.  Anybody know how to fix this?


I remember setting something that affected the font size in GUI elements such as menu bars as well as text areas in editors (such as the default font setting in gvim).  I tried to look into the "appearance" settings but could not find it.  Do you remember that setting? How to tweak it?  thanks!

I've been finding fonts on the internet and  on my system.   What's the easiest way to change my fonts? I would prefer an easy to use graphical way, but answers with command line recommendations are also welcome.


it shows error E: Type 'sudo' is not known on line 2 in source list /etc/apt/sources.list.d/google-chrome.list E: The list of sources could not be read. tried to install google chrome ans it lead me here

I'm a first time Linux user. My laptop wasn't connecting to the wifi so I followed the instructions from .  On typing sudo apt-get update after that, I got this error:  E: Type 'sudo' is not known on line 2 in source list /etc/apt/sources.list E: The list of sources could not be read.   What can I do?


What difference in meaning is achieved by omitting an indefinite article in the second of the following phrases: 'a half of a yellow sun' and 'half of a yellow sun'?

This argument has come up at work, and I actually found it pretty interesting.  My colleague is arguing that you might say "a quarter of a pizza", whereas you'd just say "half of a pizza" rather than "a half of a pizza".  So my question is:   Which is correct: "a half of an [x]", "half of an [x]", or both? Is there a difference in how we treat the word "half" as opposed to "quarter" or other fractions? If so, why?   Hopefully this isn't a duplicate - there are some   on the site, but nothing that addresses the first "a" used.


It is well known that if a normed space is finite-dimensional, then all norms are equivalent. Does the reverse implication hold as well? Thank you for your help!

On an infinite dimensional, do there exist two norms which are not equivalent?  I actually know that on a infinite dimensional space, the number of inequivalent norms are $ 2^{dimX} $ However, I want to know if we can explicitly construct two inequivalent norms on any given space.


Can someone please tell me how to upgrade Ubuntu 13.10 to Ubuntu 14.04 ... it gives an error that "third party sources are disabled".. I don't know how to enable them.

What are the different ways I can use to upgrade Ubuntu from one release to another?


Possible spoilers for the D&D 5E adventure Curse of Strahd:   So last week my players encountered Strahd at level 3. My intention with this is to teach the players to think before spending their valuable resources. Strahd would not have killed them right away - he was only toying with them and testing their strength. But then one of my players said "I have wooden stakes, I want to stake him in the heart."  We are all new players and I am a new DM. Since 5e has no rules for called shots, I told them that it would be such a difficult hit that they needed to roll a flat 20 on the dice for a critical hit. They then started to "fish" for a critical hit with two weapon fighting and 2 wooden stakes each. I felt like it was a poor way of handling this situation   They've also tried to "call shots" before. The war cleric wanted to hit an enemy on the legs to make it fall prone and the way I handled it was telling them that the battlemaster archetype of the fighter has a similar feature called maneuvers and it would be a boring class if everyone was be able to do it.  So my question here is: how do you handle it when your players want to call shots?

My players have been asking to improvise specific combat actions, mostly the archer wanting to aim at specific body parts. I haven't been able to find anything in the DMG or the PHB on the subject so I was wondering how I should deal with this.    How (if at all) should an attack roll be modified when targeting a specific body part? If there is not RAW on this I am open to playtested house rules per .


In Gaussian Processes, SVMs, kernels are used (as to my understanding) as similarity measure. However, they have the constraint that any kernel has to be represented as a dot product. i.e. $k(x_1,x_2)=\langle f(x_1), f(x_2)\rangle$. Note that $f(x)$ could map x to a higher dimension e.g. $f(x)=[x^2\,\,\,\, \sqrt{2}x]^T$  My question is how can you derive the square exponential function $k_{SE}=\exp(-(x_1-x_2)^2)$ as a dot product.

How to prove that the radial basis function $k(x, y) = \exp(-\frac{||x-y||^2)}{2\sigma^2})$ is a kernel? As far as I understand, in order to prove this we have to prove either of the following:   For any set of vectors $x_1, x_2, ..., x_n$ matrix $K(x_1, x_2, ..., x_n)$ = $(k(x_i, x_j))_{n \times n}$ is positive semidefinite. A mapping $\Phi$ can be presented such as $k(x, y)$ = $\langle\Phi(x), \Phi(y)\rangle$.   Any help?


I have a recently-updated extract from NHD High Resolution (updated in last 6 months) which means it hasn't been cranked through NHDPlus, and won't for many years to come, and thus has no Stream Order (Strahler) attribute.   Running it through Arc Hydro (burn streams) and then through SA Stream Order tool doesn't work: That generates a new stream network! Converting the NHD to a raster and combining it with FDR, another miserable fail.  A few tools (RivEX, NVS Vector Stream Tools) "Claim" they have the ability to determine stream order from a vector network, but I have yet to see that work, and their tools are made for "Lab" (perfect) environments.  I'm able to generate FromNODE ToNODE on this network, is there some easy-button in Arc Toolbox that can pull this off? REALLY need to have Stream Order on this dataset covering 700,000 acres, will take the interns a long time......

I have a shapefile which contains the streams that were digitized from a satellite Image. I would like to calculate the stream order for this data. The data does not exactly match the DEM that I have, since the satellite image was of much higher resolution.  Is there any arcscript, code or readymade tool which I could use to calculate the stream orders?  I have Arcgis 10 with spatial & 3D analyst, as well as QGIS.


I just don't understand what Heisenberg meant by the statement that "It is impossible to determine both position and momentum of an electron simultaneously.If one quantity is known then the determination of the other quantity will become impossible." Now, it obvious that position of an object can not be determined if it is in motion or having a momentum because it is continuously changing its position. If it is at rest we can determine its position but not momentum since it has a zero velocity. Did he mean that electron never come to rest?

I have heard several pseudoscientific explanations about the  and find them hard to believe.  As a mathematician mainly focusing on functional analysis, I have a considerable interest in this matter. Although I still have no idea about it, I aim to truly understand it one day. For now, the question is:  Can the Heisenberg Uncertainty Principle be explained so that a non-scientist can at least get a correct idea of what it says and what not?  One of the most heard explanations is the one that says naïvely that while trying to determine the position of a particle you send energy (light) so you modify its speed, therefore making it impossible to determine the speed. If I understand well this should only be a some sort of metaphor to explain it, right?


I get Eclipse 3.8 in apt-get, and having a problem with .nb files with it  about How to Have Mathematica 10 Workbench in Ubuntu 16.04? I do not understand how this can possible that only 3.8 in apt-get, since 3.8 is already two years old.

I want to have this  in Ubuntu 16.04.  I want to include .m files in my project as functions to keep things organized.  You can use Eclipse 3.8 or 4.5 to reproduce the problem.  I downloaded now the official Workbench_2.0.0_ECLIPSE.zip in my Wolfram user page. It has the Wolfram Workbench plugins.  I managed to import it in my system.  I managed to disable the two software sources below for 3.8 Eclipse, since I am using 4.5.   Still, I cannot start .nb file in my Mathematica Development of Eclipse. I get the same error as in the screenshot below under the section.  It would be great to understand those plugins which downloaded/installed in Wolfram Premiere service.   How can you test if the Wolfram Workbench .zip file is correctly installed in Eclipse?    Eclipse 3.8 with other sources  I install Eclipse 3.8.  I follow the instructions in the thread  and successfully install the sources        However, they do not seem to work with Mathematica 10. In Eclipse, I create Basic Mathematica project. Add project where .m and .nb files. The .m open successfully. However, clicking .nb file gives the error    which suggests me that the sources install the plugins for old Mathematica (7).   Eclipse 4.5 Mars with other sources  I uninstall Eclipse 3.8, and install the precompiled Eclipse 4.5 of the official site  by solving the case together  about To Have Eclipse 4.5 in Path?  I however get the same error as in 3.8.  How can you have .nb files of Mathematica 10 Workbench in Ubuntu 16.04?


I have two classes: Customer and MovieSeating. (the problem condition is in the assignCustomerAt method in MovieSeating)  public class Customer {     private String lastName;     private String firstName;      // This constructor sets the first name and last name to "???"     public Customer(){           lastName = "???";           firstName = "???";     }       // This method returns a string containing a customer's initials       // (first characters of firstName and lastName.)       public String toString()       {            String result = firstName.charAt(0) + "." + lastName.charAt(0) + ".";            return result;       }         }   So something.toString(); returns "?.?."  Right?  All is well BUT then there's this.  public class MovieSeating{ public Customer[][] seating; public int rowNumber; public int colNumber;  public MovieSeating(int rowNum, int columnNum){     rowNumber= rowNum;     colNumber=columnNum;     Customer thisGuy = new Customer();     Customer[][] seaTing = new Customer[rowNum][columnNum];     for(int i = 0; i<rowNum;i++){         for(int j = 0; j<columnNum; j++){             seaTing[i][j] = thisGuy;         }     }     seating = seaTing; }    public boolean assignCustomerAt(int row, int col, Customer tempCustomer){      String a = seating[row][col].toString();             if(a=="?.?."){     //THE CONDITION IN THIS IF STATEMENT IS THE PROBLEM                  seating[row][col] = tempCustomer;                  return true;             }             return false; }   The purpose of the last method is to assign someone to a spot if and only if the seat is not taken (as noted by the customer having the initials "?.?."). But regardless, when the value of String a is "?.?.", the condition returns false. I've tried and tested to see that seating[row][col].toString(); returns "?.?." and it sure does. I've put parenthesis around each item and tried making two different strings and this and that and nothing works! It's like saying that (1*1) != 1. What's the deal???? Thanks in advance

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


i have problem with Arabic characters when i do json_encode() it always return ????, in the database all the fields and database is utf8  my code:  $query   = mysql_query("SELECT * FROM `Names`");  if (!$query) { $message  = 'Invalid query: ' . mysql_error() . "\n"; die($message); }else {     while ($row = mysql_fetch_assoc($query))      {      $result[] = array(         'Mid' => $row['Mid'],          'Uid' => $row['Uid'],          'Cid' => $row['Cid'],          'Name' => $row['Name'],         'city' => $row['city'],         'status' => $row['status'],         'Mobile' => $row['Mobile'],         'Phone' => $row['Phone'],         'Email' => $row['Email']);     }       header('Content-Type: application/json; charset=utf-8');       echo json_encode($result); }   the result look like:  [{"Mid":"17","Uid":"1","Cid":"8","Name":"???? ?? ??????? ?? ???","city":"?????",   please help me

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


The newest version of Windows 10 Home (version 1511) brings with it a whole slew of new stuff. It also brings with it its own handful of problems.  One of these is the apparent inability to create user groups. The  that Microsoft documents works for systems running 7 and a number past that; it worked on my Windows 8, 8.1 and previous versions of 10.  However, in the current version of 10, the lusrmgr.msc Microsoft Management Console snap-in is unavailable. This is the way adding a group would normally be done.  Lacking this function, how can I add a security (user) group in the latest edition of Windows 10 Home?

The Local Users and Groups Manager doesn't like running on the Home versions of Windows...    Is there an alternative program which can provide the same amount of flexibility for editing users/groups?  (Control UserPasswords2 doesn't have nearly as much flexibility, so that doesn't count.)


The official theorie says that they don't need a medium, it states that:   EM waves are a disturbance in the field  First of all, what field?? An electromagnetic one ? I mean, I consider that field as a medium, and from where does the field come, it is the ones that electrons in atoms create??, because that's a charge flowing and that should make a  electromagnetic field.  But here comes the question:  If we could create a total vacuum without any single atom or thing inside there, and with no electromagnetic field outside it affecting the vacuum, do EM waves would propagate??  PD: Wait for more "mindblowing" questions relative to my tastes.

As I understand it, electromagnetic waves have two components which are the result of each other, i.e., when a moving electric charge creates a changing magnetic field at point X then a changing electric field is created at point Y and this repeating process is what creates EM waves, so therefore, it requires no medium. Is my understanding correct?  One thing that I'm surprised to know is that light is also called an electromagnetic wave.  Does this include light of any kind, for example: light from a bulb, a tube, and also from the Sun? How do they contain electric and magnetic fields?


Am on Server 17.10 and am copying a directory that is some 500Gb in size, so is there a way to  continue doing something else while the directory copies?? The transfer has already been started and there is no progress report, only the cursor blinking.

How do I run a program in the background of a shell, with the ability to close the shell while leaving the program running? Lets say my UI is having problems or for some reason, I need to boot up a program from the terminal window, say, nm-applet:  nm-applet   When it's started, it occupies the foreground of the terminal window.  Is there any simple way to run the program in the background without needing to leave the terminal open or have it occupy the whole terminal?  On that note, I did find a way to run programs from the terminal and have it allow for other inputs, by appending an ampersand (&) to the command as such:  nm-applet &   But this isn't much use as any processes started in the terminal are killed once the terminal is closed.


I'm using Drupal 7.  I'm trying to get all users with custom field field_id:  $users = user_load_multiple(array(), array('field_id' => '123456789')); var_dump($users);   and I got the following error:  PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'base.field_id' in 'where clause': SELECT base.uid AS uid, base.name AS name, base.pass AS pass, base.mail AS mail, base.theme AS theme, base.signature AS signature, base.signature_format AS signature_format, base.created AS created, base.access AS access, base.login AS login, base.status AS status, base.timezone AS timezone, base.language AS language, base.picture AS picture, base.init AS init, base.data AS data FROM {users} base WHERE (base.field_id = :db_condition_placeholder_0) ; Array ( [:db_condition_placeholder_0] => 123456789 ) in DrupalDefaultEntityController->load() (line 191 of C:\wamp\www\my_proj\includes\entity.inc).  My questions: 1. How can get users by custom field ?  2. How to query the field type ? (is it text, int, float, etc..).

I want to write a function that returns users which have entered a certain value to a custom user field.   Lets say there is a custom birthday field for every user. What would be the best way to get all users with a certain birthday?  I could create a DB query that searches the field_data_field_birthday table and returns the entity_id(s) (which in this case would be the users id(s)) for which the field_birthday_value matches a given value and then load the user(s).   This seems a little bit crude, are there generic functions for this use case available? In the entity API or the field API maybe?


I am trying to create a python script that will keep track of a log file which is piped output from a console. If an "Error" pops up in it, I would like to send myself a telegram message (I know that API) so I can get a notification that I got an error. So what I would like to do is simply this in pseudocode  while true:     if isModified(file):          print(changed_text)   I'm not sure if something like this is possible, but it would be great if someone can assist with an idea or process.

I have a log file being written by another process which I want to watch for changes. Each time a change occurs I'd like to read the new data in to do some processing on it.  What's the best way to do this? I was hoping there'd be some sort of hook from the PyWin32 library. I've found the win32file.FindNextChangeNotification function but have no idea how to ask it to watch a specific file.  If anyone's done anything like this I'd be really grateful to hear how...  [Edit] I should have mentioned that I was after a solution that doesn't require polling.  [Edit] Curses! It seems this doesn't work over a mapped network drive. I'm guessing windows doesn't 'hear' any updates to the file the way it does on a local disk.


Will it be appropriate printed quality if use images at original size with resolution 72 dpi in banner 80 cm x 200 cm?

(This question is meant to be a resource to direct others to given that this is a common question.)  Given the task of creating an image that will be printed at a certain size, what pixel dimensions and resolution should I be setting my file at?


How would I append Date, Time, and Second to all of my folder names.  for /D %%f in (C:\Reports*) do rename "%%f" "%%~nxf"

Update: Now that it's 2016 I'd use PowerShell for this unless there's a really compelling backwards-compatible reason for it, particularly because of the regional settings issue with using date. See @npocmaka's     What's a Windows command line statement(s) I can use to get the current datetime in a format that I can put into a filename?  I want to have a .bat file that zips up a directory into an archive with the current date and time as part of the name, for example, Code_2008-10-14_2257.zip. Is there any easy way I can do this, independent of the regional settings of the machine?  I don't really mind about the date format, ideally it'd be yyyy-mm-dd, but anything simple is fine.  So far I've got this, which on my machine gives me Tue_10_14_2008_230050_91:  rem Get the datetime in a format that can go in a filename. set _my_datetime=%date%_%time% set _my_datetime=%_my_datetime: =_% set _my_datetime=%_my_datetime::=% set _my_datetime=%_my_datetime:/=_% set _my_datetime=%_my_datetime:.=_%  rem Now use the timestamp by in a new ZIP file name. "d:\Program Files\7-Zip\7z.exe" a -r Code_%_my_datetime%.zip Code   I can live with this, but it seems a bit clunky. Ideally it'd be briefer and have the format mentioned earlier.  I'm using Windows Server 2003 and Windows XP Professional. I don't want to install additional utilities to achieve this (although I realise there are some that will do nice date formatting).


I'm currently facing a little problem. I'm using ACF plugin which generate complex meta_key names when creating hierarchical fields.  I found in my database meta_key named modules_1_content_0_module.  I want to be able to retrieve all the posts which have a meta_key which finish with _module and where meta_value is a given id.  Is it possible to do that directly with the WP_Query API ?  Thanks

I have a function that stores the "like" status for a post as post meta. I want to associate that "like" with the user that liked it, so I setup a custom field called "like_status_{user_id}" (where {user_id} is the id of the currently logged in user) which I store as a 0 or 1. So for a post with several "likes" there would be several meta values in the db that are setup like this:  'meta_key' = 'like_status_0' 'meta_value' = 1 'meta_key' = 'like_status_2' 'meta_value' = 1 'meta_key' = 'like_status_34' 'meta_value' = 1   ....and so on.  There are potentially thousands of likes on a specific post. How would I run a query that showed if someone else also liked that post?  I was thinking something like this:  $query = new WP_Query(array(     'meta_key' => 'like_status_{user_id}',     'meta_value' => 1, ));   I'm trying to push a notification to everyone who has liked a post when someone else likes that post...something like, "Hey, someone else liked that post you liked. You should go check it out!" But I need a way to find out if anyone else has liked that post and if so, who they would be so I could notify them.  If it's not possible, could you suggest a better way of storing this data as post_meta while still keeping the efficiency of quickly updating a single user's like status on a post?


I really like the Geany text editor, and would like to use it instead of gedit for all text editing.  However, every time I try to launch Geany from the terminal using sudo geany file.conf, I get this error:  (geany:10203): Geany-WARNING **: Geany tried to access the Unix Domain socket of another instance running as another user. This is a fatal error and Geany will now quit.  I am the only user logged in to the machine.  There are no instances of Geany already running when I type that command into the terminal.  Geany has no trouble launching from the command line if I don't use a sudo.  I also don't have any trouble running Gedit with elevated privileges; the command sudo gedit file.conf functions flawlessly. What is going on here?  How can I fix this so that I can edit text files in Geany with elevated privileges?

For example, I'm trying to run Archive Manager from Ubuntu Desktop (10.04) under sudo otherwise it won't let me extract a Software Development Kit into /usr/local  Update: I don't want sudo to be a permanent change to launching the application; only to run it under sudo when I choose, until it's quit.


I have a question about the limit of the factorial function. How can I evaluate  $$ (1) \lim_{n \rightarrow \infty} \frac{10^n}{n!} $$  $$ (2) \lim_{n \rightarrow \infty} \frac{n^n}{n!} $$  Is there any alternative expression for the factorials to solve this problem?

Why is     $$\lim_{n \to \infty} \frac{2^n}{n!}=0\text{ ?}$$   Can we generalize it to any exponent $x \in \Bbb R$? This is to say, is     $$\lim_{n \to \infty} \frac{x^n}{n!}=0\text{ ?}$$     This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


I need to match a regex on Java when a string does NOT contains an email anywhere in the string: the beginning, middle or end.   For example:  string with no email [match]  myMail@mail.com string with email at the start [no match]  String with myMail@mail.com in the middle [no match]  String with email at the end myMail@mail.com [no match]  myMail@mail.com [no match]   The regex I have managed to come up with so far is an inverse version of a popular email regex:   "^(?![_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$).*$)";    works for me only when I have just an email;   myMail@mail.com [no match]   but I need it to give me no match for ALL the examples containing an email. Any ideas how it can be done? Thanks  edited:  Found the answer by looking at     The working line is:  "^((?![_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})).)*$)";   Thanks

I know it's possible to match a word and then reverse the matches using other tools (e.g. grep -v). However, is it possible to match lines that do not contain a specific word, e.g. hede, using a regular expression?   Input:  hoho hihi haha hede   Code:  grep "<Regex for 'doesn't contain hede'>" input   Desired output:  hoho hihi haha


Does Ubuntu have a command prompt like Windows and if so where do I find it to display the directory tree

What is the command that can be used to draw the directory tree inside the terminal emulator?


I am curious to know from other users who are knowledgable with LiION batteries.  I work on a MacBook and just recently got a new machine.  From all my research of LiIon batteries, the optimal life to maintain the charge from studying EV-Car technology is to maintain charge from 20%-80%.  Is the same true on the MacBook?    Since both use LiIon i figure there should be parallels, but I figure there are differences with power management which may be chip-based.  Thoughts?  Thanks in advance.  Tri

My friend told me that I need to disconnect the power cord when the battery is fully charged. Otherwise, I will shorten the life of the battery.  Other people say you should drain it once a month or point out that for long term storage, you should charge it to 50% and then periodically (3 to 6 months) bring it back to 50% and store it again.  I am going to use my laptop at home 90% of the time. So, I plan to have the power cord connected all the time.  I'd prefer to just plugging in my MacBook Pro and letting it be on charge long term and occasionally taking it away from the charger when I'm not at home or my desk.  Are these specific recommendations worth the inconvenience?


I found an elevated place in Minecraft and would like to expand its borders. However it seems I can't add a block adjacent to a surface without being able to see that surface, and on an elevated area this means I'll have to be off of the area in order to accomplish this. Is there a way to create a cantilever-like structure, specifically, a way to extend a 'floating island'?

I want to build a bridge over a valley to allow fast travelling between 2 areas. The only way I can see to do it is this:   Build steps up to the level I need. Move right to the end of the last block placed Turn around so I can see a bit of the face of the last block Place the block so it extends the length of the bridge Repeat from step 2.   This is slow because you you have to carefully navigate yourself to the precarious edge of a block each time.  Is there an easy way to place a block adjacent to an existing block without having to look back from beyond the edge of the existing block?  If my description doesn't make sense I may need to resort to ascii art.


What is   $$\lim_{x \to 0^+} f(x)\quad\text{ where }\quad f(x) =\left( \frac{\sin x}{x}\right)^{1/x^2}$$  ? The problem suggests to use a Taylor expansion, but it is not clear to me what to expand.

I have got this problem on limits  $$ \lim_{x \rightarrow 0}\left(\frac{\sin(x)}{x}\right)^\frac{1}{x^2}$$ What I am doing here is that taking log and then applying L-Hospital's Rule $$y= \lim_{x \rightarrow 0}\left(\frac{\sin(x)}{x}\right)^\frac{1}{x^2} $$ then $$\ln(y)=\lim_{x \rightarrow 0} \frac{1}{x^2}\ln\left(\frac{\sin(x)}{x}\right)$$ now it becomes $\frac{0}{0}$ type , but problem is how to take derivative here? when differentiating $\ln\left(\frac{\sin(x)}{x}\right)$ it will become $\frac{x}{\sin(x)}$ then we'll have to differentiate one more time like we do in case of $f(f(x))$ ? $\sin(x)$ and $x$ will be separately differentiated or together ?


I can not get the plot stretched to the whole area of the figure. When I call the tight_layout, the required height of the plot is obtained, but I can not achieve the required length:     Code:  self.figure = plt.figure()     self.canvas = FigureCanvas(self.figure)     # self.figure.set_figheight(15)     # self.figure.set_figwidth(5)     #self.figure.tight_layout()     self.figure.set_size_inches(1, 7)     self.graphBox.addWidget(self.canvas)      # ------------------------------------------------------------------     # ------------------------------------------------------------------     t = np.arange(0.0, 2.0, 0.01)     s = np.sin(2 * np.pi * t)     ax = plt.subplot2grid((1, 1), (0, 0))     ax.set_facecolor(color='#b3ff66')     ax.plot(t, s)     self.canvas.draw()     #plt.tight_layout(h_pad=1.0, w_pad=1.0)     # ------------------------------------------------------------------     # ------------------------------------------------------------------

How do you change the size of figure drawn with Matplotlib?


$X$, $Y$ and $Z$ are three random variables where their pairwise correlations are the same, i.e., $corr(X,Y)=corr(Y,Z)=corr(X,Z)=\rho$ what are the possible values of $\rho$?  I was asked this in an interview (data analyst).

There are three random variables, $x,y,z$. The three correlations between the three variables are the same. That is,  $$\rho=\textrm{cor}(x,y)=\textrm{cor}(x,z)=\textrm{cor}(y,z)$$  What is the tightest bound you can give for $\rho$?


I have this very weird error in the constructor of my class.  #include "ContratException.h" //#include "File.h"   namespace labPileFile {  template<typename T> File<T>::File(const int max) :         m_tete(0), m_queue(0), m_tailleMax(max), m_cardinalite(0) {     m_tab = new T[m_tailleMax]; }  template<typename U> std::ostream& operator <<(std::ostream& p_out, const File<U>& p_source) {     p_out << "[";     for (int i = 0; i < p_source.taille(); ++i) {         p_out << p_source[i] << ",";     }     p_out << "]";     return p_out; }  }   Eclipse gives me several "Expression cannot be used as a function" errors   All three errors are the same thing.  here is my .h, if it can help (I have to create the .cpp from the .h that I was given)  #ifndef _FILE_H #define _FILE_H  #include <iostream> #include <stdexcept>  namespace labPileFile {  template<typename T> class File { public:     File(const int = MAX_FILE);     ~File();      File(const File<T> &);     const File<T> & operator =(const File<T> &);      void enfiler(const T &);     T defiler();      int taille() const;     bool estVide() const;     bool estPleine() const;      const T & premier() const;     const T & dernier() const;      T operator [](const int &) const;      void verifieInvariant() const;  private:     T *m_tab; /*!< Content of the queue*/     int m_tete; /*!< Head of the queue (first index)*/     int m_queue; /*!< Last index of the queue*/     int m_tailleMax; /*!< Current capacity of the queue*/     int m_cardinalite; /*!< Number of elements*/     static const int MAX_FILE = 100; /*!< Default capacity*/ }; }  #include "File.hpp"  #endif   Does anyone know what I'm doing wrong?

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


Let $K$ be any algebraically closed ground field. For $X \subset \mathbb{A}^n$ and $Y \subset \mathbb{A}^{m}$ irreducible affine varities, I am trying to show that the product affine variety $X \times Y$ is also irreducible by showing that the coordinate ring $A(X \times Y) = K[x_1,...,x_{n+m}]/I(X \times Y)$ is an integral domain.  I am trying to do this by contraposition but am stuck. Here is what I have:  Since $X$ and $Y$ are affine varities so $X=V(S)$ and $Y=V(T)$ for some subsets $S \subset K[x_1,...,x_n]$ and $T \subset K[x_1,...,x_m]$. Then $X \times Y = V(P)$ where $P \subset K[x_1,...,x_{n+m}]$ is the set of all polynomials from $S$ considered as polynomials in $n+m$ variables by setting the last $m$ variables equal to zero, along with the polynomials from $T$ considered as polynomials in $n+m$ variables by setting the first $n$ variables equal to zero.   We also have that $V(P)=V((P))$ where $(P)$ is the ideal generated by $P$. Hence  $A(X \times Y)=K[x_1,...,x_{n+m}]/I(X \times Y) = K[x_{1},...,x_{n+m}]/\sqrt(P)$ by Hilbert's Nullstellensatz. Assuming $A(X \times Y)$ is not an integral domain there exits $f,g \neq 0$ such that $f,g \in \sqrt(P)$; moreover we can assume that this implies that $fg \in (P)$ since, if not, then since for some $k$ we have $(fg)^k = f^kg^k \in (P) \subset \sqrt(P)$, $f^k$ and $g^k$ are also zero divisors so we just choose $f=f^k$ and $g=g^k$ instead.     I'm not sure if what I've done so far points me in the right direction, but I am at a loss for seeing how to show that $X$ or $Y$ must be reducible.    Edit: My question was unfairly marked as a duplicate thread. None of the threads cited as alleged duplicates address how to prove that this is irreducible by showing that the coordinate ring of the product is an integral domain.

Let $k$ be an algebraically closed field and $X,Y$ varieties (i.e. integral, separated schemes of finite type over $k$). Is the fibre product $X \times_k Y$ necessary irreducible or integral?     I have another more or less related question:      If $A,B$ are finitely generated $k$-algebras which are also integral domains, is $A \otimes_k B$ an integral domain?


Let $(X,\mathcal{A},\mu)$ and $(Y,\mathcal{B}, \nu)$ be measure spaces such that $\mu(X)>0$ and $\nu(Y)>0$. Let $f:X \rightarrow \mathbb{R}$ and $g:Y \rightarrow \mathbb{R}$ be measurable functions (with respect to $\mathcal{A}$ and $\mathcal{B}$ respectively) such that $$f(x)=g(y) \text{   $\mu\times\nu$-almost everywhere on $X\times Y$}$$ Show that there exists a constant $\lambda$ such that $f(x)=\lambda$ for $\mu$-a.e. $x$ and $g(y)=\lambda$ for $\nu$-a.e. $y$.  Here is what I was working on: Consider $E = \{ (x,y) : f(x)=g(y) \}$. Then, $\mu \otimes \nu (E^c)=0$. Thus, $$ 0 = \iint_{X \times Y} 1_{E^c} \, d\mu \otimes d\nu = \int_Y \int_X 1_{E^c} \, d\mu \, d\nu,$$ by using Fubini (since $1_{E^c}$ is integrable) or Tonneli (since $1_{E^c}$ is nonnegative). Now, this yields that $\int_X 1_{E^c} \, d\mu = 0$ $\nu$-a.e. Hence, we can pick $y \in Y$ such that $f(x)=g(y)=:\lambda$ $\mu$-a.e. You can do a similar argument to show that $g(y) = \lambda$ $\nu$-a.e.  Now, I realize that I cannot use Fubini or Tonneli unless the measures are $\sigma$-finite, and I haven't used the fact that $\mu(X)>0$ or $\nu(Y)>0$. What am I missing?

Consider two measure spaces $(X,\mathcal{A},\mu)$ and $(Y,\mathcal{B},\nu)$, where $\mu\times\nu(X\times Y)>0$. Given two measurable functions $f:X\to \mathbb{R}$ and $g:Y\to\mathbb{R}$ such that   $$f(x) = g(y)   \qquad\mu\times\nu \,\,\text{a.e,}$$  does it follow that there exists a constant $\lambda$ such that $f(x)=\lambda$ for $\mu$-a.e. $x$ and $g(y)=\lambda$ for $\nu$-a.e. $y$?  Clarification: The displayed statement means that $\mu\times\nu\big(\{(x,y):f(x)\neq g(y)\}\big)=0$.  I know that this is true when you assume $\mu$ and $\nu$ are $\sigma$-finite, by applying Fubini's theorem to $\int |f(x)-g(y)|\,d(\mu\times\nu)$. In the general case, the only first step I can think of is to find a countable set of rectangles with arbitrarily small total area where $f(x)=g(y)$ on the complement of their union. But there I'm stuck.


Let $a(x)$ and $b(x)$ be smooth functions, i.e they are infinitely times differentiable.  I have made the assumption that the derivative for the function   $$f(x)= (a\cdot b)(x)$$  can be given by   $$f^{(n)}(x)=\sum_{k=0}^{n}\binom{n}{k}a^{(k)}b^{(n-k)}(x)$$  Where I have defined $g^{(n)}$ as the $n-$ th derivative of some function.  I have made the observation when I was trying to calculate the derivative of such a function and I noticed that the derivatives are in the form:  $$f^{(1)}(x)=a'b+b'a$$  $$f^{(2)}(x)=ab''+2a'b'+a''b$$  $$f^{(3)}(x)=ab'''+3a'b''+3a''b'+a'''b$$  What I have tried so far is induction but I don't know how to manipulate the formula to get the result I want  $${f^{(n+1)}=f^{(n)}}^{'}=(\sum_{k=0}^{n}\binom{n}{k}a^{(k)}b^{(n-k)})^{'}=(\sum_{k=0}^{n}\binom{n}{k}[a^{(k+1)}b^{(n-k)}+a^{(k)}b^{(n-k+1)}])$$  Now I cannot say something like :  $$[\uparrow]=(\sum_{k=0}^{n}\binom{n}{k}[a^{(k)}b^{(n-k)}(a+b)]) $$   Because they are derivatives and they do not necessarily behave like exponentials. But I don't know if it even would help me  Because in the end I want to have a term that Looks like  $$\sum_{k=0}^{n+1}\binom{n+1}{k}a^kb^{n-k}$$  But I don't know how to do it.

Possible Duplicate:          The  describes the expansion of the $n$th power of the sum $(a+b)$:  $$(a+b)^n = \sum_{k = 0}^n {n\choose k}a^kb^{n-k}$$  In calculus, there is a generalization of the product rule called , which describes the expansion of the $n$th derivative of the product of two functions $f$ and $g$:  $$(fg)^{(n)} = \sum_{k = 0}^n {n\choose k}f^{(k)}g^{(n-k)}$$  It's not difficult to prove using the product rule and induction, what I'm really trying understand here is why the formula is true. Is there a way to prove it using the binomial formula? How are these two formulas related? Is there a combinatorial proof for Leibniz's rule like there is for the ?   I understand this question is a bit vague, but I hope you'll agree that these two formulas look so similar it just feels like there should be some relation between the two. Of course this is not necessarily true, but I'm hoping it's not just a crazy coincidence.


I installed MikTex following this :  sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys D6BC243565B2087BC3F897C9277A7293F59E4889  echo "deb http://miktex.org/download/ubuntu xenial universe" | sudo tee /etc/apt/sources.list.d/miktex.list  sudo apt-get update   I got this note message:  N: Skipping acquire of configured file 'universe/binary-i386/Packages' as repository 'http://miktex.org/download/ubuntu xenial InRelease' doesn't support architecture 'i386'   How to get rid of this?

Needing to upgrade Squid 3.5.12 on Ubuntu 16.04.3 LTS to a more recently patched version (Squid 3.5.23) I found some instructions here:   Entered the first 3 commands exactly and got a note from apt-get: "N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository ' xenial InRelease' doesn't support architecture 'i386'"  I don't have typos and nonexistent foreign architectures as others have done:  root@wprdsqd01:/# dpkg --print-foreign-architectures i386 root@wprdsqd01:/# dpkg --print-architecture amd64 root@wprdsqd01:/#   Does this just mean that the repository doesn't have i386 (32bit) binaries ?  Thanks