I've made a image gallary with sortabele options, hover and a delete button on every image.

    <button class="deleteMedia">Delete</button>
  <li ....
             With AJAX I add an image to the gallery. This works fine, but the hover and the delete button doesn't work for the new added images. My jquery script for the hover and delete event (what works well for the existing images) is:     $("#media-list .deleteMedia").click(function() {        $(this).parent().remove();     });      // Hover images     var offsetX = 20;     var offsetY = -400;     $('a.hover').hover(function(e){          var href = $(this).attr('href');         $('')         .css({'top':e.pageY + offsetY,'left':e.pageX + offsetX})         .appendTo('body');     }, function(){         $('#largeImage').remove();     });     $('a.hover').mousemove(function(e){         $('#largeImage').css({'top':e.pageY + offsetY,'left':e.pageX + offsetX});     });     $('a.hover').click(function(e){         e.preventDefault();     });  I push the image with this AJAX-code: $("#media-list").append("<li id ... </button>
");  What could I do to bind the 'hover and deletebutton' events to the new image, and not double to the existing images?

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


Is there a program that can make live USBs for any distro, iso, you get the point. I can only find ones that make live USBs for other linux distributions and none for anything else.

Is there any software like unetbootin in Ubuntu?  I cant install or run unetbootin-494 even though I already set it to allow executing files as programs.


For an individual who was self-employed part of this year and contributed to an .  Now the individual is employed and covered under a standard 401(k).    Does the solo 401(k) contribution lower the 18K contribution limit to the 401(k)?

I was self employed during the first quarter of 2011, then switched to full time employment.  I have a solo 401k that I haven't contributed to in tax year 2011.  I have been contributing to my employer's 401k (to capture the match).  Can I still make a contribution to my solo 401k, or is it disallowed because I participate in another plan?  If it is allowed, what limits are in effect for the combined contributions (solo + regular)?


Let $f:G\to G$ when $f=x^2$ if $f$ is homomorphism then $G$ is abelian group.  suppose $f$ is homomorphism so $f(xy)=f(x)f(y)$ $\forall x,y \in G$   then $xy=yx$  how to prove  this sentence.

Let G be a group. The function $f:G \rightarrow G$ defined by $f(x)=x^2$ is a homomorphism iff G is abelian.  I am having trouble with the 2nd part of the proof.  Proof:  Assume the function $f:G \rightarrow G$ is defined by $f(x)=x^2$ then:   Assume $f$ is a homomorphism then $f$ satisfies the property: $$ f(xy)=f(x)f(y) $$   where $x,y \in G$  Notice how: $$f(xy)=(xy)^2=xyxy$$ $$f(x)f(y)=x^2y^2=xxyy $$  Since $f(xy)=f(x)f(y)$ then by substitution:  $$xyxy=xxyy$$  Multiplying the right by $y^{-1}$ and the left by $x^{-1}$ then:  $$yx=xy$$ which means G is abelian   Assume G is abelian, we want to show $f$ is a homomorphism   For the 2nd part of the proof, would I just work backwards from the first part of the proof? Here is an outline:  then for $x,y \in G$  $$yx=xy$$ by definition of abelian groups.  Multiple the right by y and the left by x, we have:   $$xyxy=xxyy$$  which is equal to: $$(xy)^2=(x)^2(y)^2$$  since we are given $f(x)=x^2$ then translating this to the above statement: $$f(xy)=f(x)f(y)$$  which satisfies the property of homomorphism.  Does that look right?


I have a lot of spare space in my hard disk. But the size of / partition is very small. Here is a snap of my partition table in Gparted,    How can I expand my / partition? Step by step description will be helpful.

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


If one is playing a Mystic Theurge in 3.5 and the Wizard side has school specialization, would the banned schools also be affected on the cleric side.  If you had banned Enchantment and Illusion would Divine spells of Enchantment and Illusion also be banned - Thanks

I've had DMs rule both ways on this..I haven't seen any official RAWs on this so I was hoping someone here could point me in the right direction?  If a Wizard specializes (giving him 1-2 prohibited schools) and later multiclasses can his cross class use the prohibited class?    ie, an "illusionist" gives up Evocation & Conjuration and later crosses into Cleric, would he be prohibited from casting healing (conjuration) spells or would it be ok now that it is divine magic and not arcane?  Or does the arcane vs divine source even matter?  So the same Wizard instead crosses into Sorcerer, can he now cast Sorcerer spells from the prohibited schools?


I have a MediaWiki 1.35.2 Hebrew website which is principally all core; I host that website on a shared Apache, Nginx (as reverse proxy), PHP and MySQL hosting environment. The default behavior of MediaWiki is to load any webpage with the PHP loader* index.php and at least one query string; The MediaWiki phenomenon I have described often raises errors in Google Pagespeed Insights about too many resources which consume loading time (maybe it's better to load these informally without query strings) and it also makes my URLs "long" instead "short" (i.e. without using this index.php method) when they are already long because of Right-To-Left language Encoding. For some reason/s I have a very hard time finding my way in the following MediaWiki guides on how to get shorter URLs without index.php and its query strings (guides that include explicitly outdated parts and/or many warnings and exceptions):

Some content management systems such as WordPress and Drupal have Short URLs by default (if the webserver allows it), but at least one other --- MediaWiki, doesn't. Before I continue with the process of trying to make my MediaWiki website to include short URLs I'd like to ask a general understanding question on the subject (because I find the ). Do short URLs obligate 301 redirects? I do understand that they always require some webserver directives but I'm just not sure if such directives must include 301 redirects or not...


I can press like more than 5 buttons in my keyboard at same time but if hold these 3 buttons { D+(S or A or W)+ I } together I can't press anything else after them Thanks.

When I slam my hand onto my keyboard, only a maximum of 6 keys will be registered, I've tested this for the past few minutes and was unable to get more than 6. Is this the same on all keyboards? If not, what would be the distinguishing factor, If yes: why 6 specifically?  For clarification: I do not have a usecase for this, I am simply curious


I have been developing in the windows space with Visual Studio for a while now with work, but I have also been using Ubuntu for a while and am keen to get into some software development for linux.  I should also note. I am not looking for .NET and I am aware of mono. I am also familiar with c++ development and some python, so the language isn't so much relevant as the "all in one" aspect.  I was interested to know if there is a useful all in one code/debug/design(gui) IDE similar to something like Visual Studio but for linux?

This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions here. See  for more information.   This is a community wiki for IDEs available on Ubuntu. Please post one IDE per answer (including more than just a screenshot or a link, please at least put a short description).  In your answer, tell us what the IDE is for (which language(s) or if it is RAD capable).


If two electrons are travelling side by side with the same velocity with respect to me, they are standing still with respect to each other. For me, they will exert on each other an electrostatic force minus a magnetic Lorentz force. But, as seen from their point of view there is only an electrostatic force. So according to me their acceleration will be greater than the one they will "feel". So how can one solve this issue ? Maybe though the acceleration will be weaker as seen by me, the time lenght during which they will accelerate will be longer too (according to me). As seen by the electrons, the acceleration will be greater but will last shorter.  Is this reasoning correct ? Can someone do the exact calculation ?

I am sure there is a simple explanation for my confusion, but I am a little puzzled:  We are dealing with two parallel electron cannons that each produces a straight beam of electrons. They are placed at a distance d next to each other, which means there will be a repulsive electrostatic force between the electrons of the two beams. Also, according to the Maxwell equations, every moving electron will produce a magnetic field which then exerts another force on the other beam's moving electrons (similar to the effect that two currents in wires will cause an attractive force between the wires).   However, if we change the reference frame such that we are moving at the same speed alongside the electrons, there will be no magnetic field and no Lorentz Force. We are only left with the electrostatic force.  Do you guys know what might be the fallacy?


I'm trying to prove the real numbers with addition isn't ismorphic to the same real numbers without 0 and with multiplication.    I've tried a lot without success. My strategy is show a contradiction from an isomorphism between them.  I need belp  Thanks

I think it wants me to show that there's no bijection between the two sets.  I first tried to show that there's simply no bijection, then I realised that it doesn't work.  If I'm to show there's no bijective morphism that carries multiplication in nonzero real numbers to addition in real numbers, how am I supposed to do it? I'm thinking about doing something with 0, since it's the element of the first set but not the second set.  Thanks!


I want some references about the history of the application of group theory in physics. Most references I found are professional textbooks, but I'm not concerned about the technical details and I don't have enough backgrounds to understand them as well, rather I'd like some popular-science style reference. Could you please recommend some references to me? P.S. I am an undergraduates in mathematics, so if a reference must contain some technical details, I'd like one with more mathematics and less physics.

I am looking for references (books or web links) which have "simple" examples on the use of group theory in physics or science in general.   I have looked at many books on the subject unfortunately they usually require extensive technical coverage of the basics, i.e. the 1st 100 pages or something, to be able to start discussing applications.  I believe that there is an easy way to explain anything (it's just hard to find it).


I'm trying to understand an example in my lecture notes, it states that $Spec(\mathbb{R}[X,Y]/(X-Y^2,X+Y))$ has only two points. Can anyone develop more please ? and how would these points be like ?  Thanks for the help.

I have the following problem:  Let $R:=\mathbb{R}[X,Y]/(Y-X^2,Y+X)$ i) Show that $R\cong_\text{Ring} \mathbb{R}\times \mathbb{R}$ ii) Conclude that $|\operatorname{Spec}R|=2$. How do these two ideals look like?  So for the first one I got the hint to eliminate one variable at a time and see what happens. Doing that I got: $1.) \mathbb{R}[X]/(-X^2,X)\cong \mathbb{R}[X]/(-X^2)\times\mathbb{R}[X]/(X)\cong\mathbb{R}[X](-X^2)\times \mathbb{R}$ $2.) \mathbb{R}[Y]/(Y,Y)=\mathbb{R}[Y]/(Y)\cong\mathbb{R}$ using the chinese remainder theorem in $1.)$. But since $\mathbb{R}[X]/(-X^2,X)\times\mathbb{R}[Y]/(Y)\ncong\mathbb{R}[X,Y]/(Y-X^2,Y+X)$ and the fact that there is still $\mathbb{R}[X]/(-X^2)$ left in the first equation, I don't see how this leads me to the desired isomorphism. For the second one I don't see how an isomorphism can lead me to the number of ideals, because I'm pretty sure $A\cong B$ doesn't imply $\operatorname{Spec}A \cong \operatorname{Spec}B$ for rings $A,B$ (I've seen it in a book). Can someone help me with this problem? Thanks in advance.


I am trying to install vivaldi.  I downloaded a .deb file of vivaldi, and i tried to install it with Ubuntu Software Center.  But, I could not install it because the Software Center just shows me the program I installed most recently.  How can I fix the problem?

I am new to ubuntu world...   How to install vivaldi browser on ubuntu? How could we find dependencies, when installing any software on ubuntu?


Please, how i can change date format in php  from something like 2012-12-14 08:40:26  to format number like 28124629523

How do I get timestamp from e.g. 22-09-2008?


I'm wondering about data normalization in CNN, how can we do it for the input images?, what can it add to the model's performance? and what are the main pre-processing techniques before doing the convolutional layer?  Happy to get extra-reading, thanks.  UPDATE:  I'm looking for how to practically normalize the data inputs, I didn't get it!  . Additional reading (explanation, papers) will be so helpful.

I am not clear the reason that we normalise the image for CNN by (image - mean_image)? Thanks!


I've been learning C++ recently and wondering whether it is possible to convert a .py file to .bin file just like we compile C++ to .bin in Linux. I found pyInstaller to convert it to exe file but what I need is to export it to a .bin file just like we get when we perform g++ test.cpp -o a.out or a.bin etc. Any help would be appreciated.

How feasible would it be to compile Python (possibly via an intermediate C representation) into machine code?  Presumably it would need to link to a Python runtime library, and any parts of the Python standard library which were Python themselves would need to be compiled (and linked in) too.  Also, you would need to bundle the Python interpreter if you wanted to do dynamic evaluation of expressions, but perhaps a subset of Python that didn't allow this would still be useful.  Would it provide any speed and/or memory usage advantages?  Presumably the startup time of the Python interpreter would be eliminated (although shared libraries would still need loading at startup).


We can change shortcuts in System Preferences - Keyboard - Shortcuts.  And many preferences has its associated file.  So I wonder if there is any file related to the shortcuts.  Then I can use version control or Dropbox to make it sync-able.

Where can I access OS X keyboard shortcuts, say for Dropbox sync?


I have seen many quasi-particle here in . Is there any quasi-particle concept for sound wave in air medium?  If it exists, what's the purpose and usefulness of it?  If it does not exist, is there any reason that people do not make such concept?

A phonon is a quantized unit of sound; they are encountered when quantizing lattice vibrations in solids. Now, even an ideal gas supports sound waves, but in this case, interactions between atoms are weak. That makes it hard to imagine what a quantized vibration would look like, since at small scales, the particles are free!   Is there a phonon picture for sound in an ideal gas? Is it ever useful?


Once I read a rule on the internet that if the second part of a sentence is a universal truth then don't change it to past.   For example: My teacher told me that the sun rises from the east.   But I'm not sure about the following examples whether it's right or wrong. Both sentences have different meaning to me   1: She told me yesterday that she was pregnant.  2: She told me yesterday that she's pregnant.  In the first example it sounds like she has already given birth to a baby and she's no longer pregnant.  In the second example it sounds like she still has some time to deliver a baby.  Am I right? And sorry if it sounds silly to you.

Are these two sentences grammatically correct?   Mona told me that London was the biggest city in England. He wanted to know where Manchester was.   I found these two sentences by chance in an exercise book published by Egypt's  Ministry of Education. Both sentences talk about a fact, and Is it unreasonable to change the verb tense in reported speech to past simple when what the sentences talks about is still true? (As my teacher and the books say.) Or is it right when we talk about facts to change the tense or is the tense change optional and  both are correct?


I'm always getting these two notifications every single day:

I have three notifications pending but when I open the tab they were a month ago. When I refresh the page I see the correct three notifications. Pictures:  Here you see notifications from March but it is April:    Here I refreshed the page and recognized that there are indeed three unread notifications.    This behavior occurred already three times before, always with the spinlock question as first comment. Today I finally realized that there were indeed notifications pending.  Is this a bug to report? If this is not the right side to ask about this - where should I go to?  Edit 1  Browser: Firefox 28.0 (current version) Windows 7 on a Laptop  It only appears on the favourites side. When I open  I see the current comments.  Edit 2  On favourites I see the old issue    On meta and stackoverflow I see the new comment   Edit3  Still an issue on April 11th and April 16th. The question is more like: Can somebody remove this or show me a way to remove it or let it remove?  Edit4  April 20th at 14:00GMT the favourite tags turned into an error page:


Which usage of var is correct:  $( 'li' ).each( function() {     var item = $( this );      // ... });   or  var item;  $( 'li').each( function() {     item = $( this );      // ... });   Both work fine, even having 'use strict'. Is there any fundamental difference between these two?  Thank you.

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


So my Thermodynamics teacher said that on a  $pV$ diagram, you can get adiabats crossing for a Carnot cycle, even if all the possible thermodynamic states of the system can be represented on a  $pV$ diagram (2 dimensions). So this is NOT the case where a third state variable is needed to define the state of the system. However, since the Carnot cycle is reversible, the adiabats on the  $pV$ diagram are isentropic processes. So how can these adiabats cross? Because the point of intersection must have either one entropy or the other, because entropy is a state function. He said this can happen with things like water, which has the same density at a certain sub-zero temperature and then at a certain above-zero temperature, so at some point there is a maximum in one of the state variables. He said that on some occasions, the  $pV$ diagram is not useful in representing the processes because of this matter of lines crossing, and that another 2D diagram would be clearer. Well, how can the adiabats cross? What could produce this situation?

Can paths of two adiabatic process intersect on a plot? This question is for both reversible and irreversible processes. There are some , but they mostly address only for reversible adiabatic processes. Also, I want a physical interpretation of the processes that is, if they don't intersect then why don't and what it would be like, physically for a system.


The trigger to use Counterspell is:     1 reaction, which you take when you see a creature within 60 feet of you casting a spell   But what if the enemy is not using a spell but a magic ability? Should I allow my players to spend the magic space trying to counter the "magic"?

Inspired by this question:   Here's the scenario:  A party member wants to fool an enemy into thinking that they are casting a spell. They take out components, do hand gestures, and starting chanting but do not actually initiate the casting of any spell. The enemy, fooled by this, casts counterspell at the pretend-spellcaster. How does this resolve?  Is counterspell successfully cast (obviously with no effect)? If so, is the slot used to cast counterspell lost?  Or, can counterspell not be initiated in the first place (since there is no real spell being cast)?


I have a following HTML code:

    Upload photo    <input type="file" name="image" id="image-upload1">

   and  $('#image-upload1').change(function() {   $('#buttonPlace1').append("<button id='closeBtn1' onclick='btnRemove1()' class='btn deleteButton'>X</button>"); })  function btnRemove1(){   $('#buttonPlace1').empty();  }   This works fine. Button is added and removed on click.. But when I remove onclick event from <button> and change btnRemove() to:  $('#closeBtn1').click(function() {   $('#buttonPlace1').empty(); })   button removing on click stops working. I'm at very beginnig of JS an jQuery and i can't figure it out.  Help please >:|

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


Treated with the inverse operator, one could get: $f(x)=x$  However, an other obvious solution is $f(x)=C$ (when f is not invertible). How could I reach this solution? Are there other solutions available?    This is not a homework.   To prove the uniqueness of the solution, I am trying (and currently failing) to do something similar to:     Thank you Jack and V. Your efforts help. I wonder if one could prove that the "projectors" are the only family of solution to Idempotence.

I am wondering what is the class of functions $f: \mathbb{R}\rightarrow\mathbb{R}$ such that $f(f(x))=f(x)$?  I think it should be:   Constant Value functions the identity function absolute value function $|x|$   But I don't know if this is right or how to show it rigorously.  Any suggestions?


I write a c# windorm application and generate a install file, when I finish the installation, every time I double click the shortcut in desktop, it will open a new window, does anyone can tell me how could I just open the original window when I double click the shortcut in desktop?

Using C# and WPF under .NET (rather than  or console), what is the correct way to create an application that can only be run as a single instance?  I know it has something to do with some mythical thing called a mutex, rarely can I find someone that bothers to stop and explain what one of these are.  The code needs to also inform the already-running instance that the user tried to start a second one, and maybe also pass any command-line arguments if any existed.


I am running a JavaScript and AJAX based chatroom. When a user leaves the page and then returns by using the Back button, they load the page from the cache. The JavaScript has to hurry and get the page back up to date, as it sees the last refresh was long ago and and requests a huge length of time in chat history to fill the gap.  What I would like instead is for the browser to be explicitly told that that HTML is invalid once they leave the page and they should do a straight refresh instead if they return to it.

Our investigations have shown us that not all browsers respect the HTTP cache directives in a uniform manner.  For security reasons we do not want certain pages in our application to be cached, ever, by the web browser. This must work for at least the following browsers:   Internet Explorer 6+ Firefox 1.5+ Safari 3+ Opera 9+ Chrome   Our requirement came from a security test. After logging out from our website you could press the back button and view cached pages.


I have an application with a UITableview and a UITextView, so sometimes the keyboard is up. Whenever the keyboard is up, I can't access the bottom 3-4 table cells because they are always stuck behind the keyboard. How can I make the UITableView only take up the space above the keyboard while the keyboard is displayed?

After a lot of trial and error, I'm giving up and asking the question. I've seen a lot of people with similar problems but can't get all the answers to work right.  I have a UITableView which is composed of custom cells. The cells are made of 5 text fields next to each other (sort of like a grid).  When I try to scroll and edit the cells at the bottom of the UITableView, I can't manage to get my cells properly positioned above the keyboard.  I have seen many answers talking about changing view sizes,etc... but none of them has worked nicely so far.  Could anybody clarify the "right" way to do this with a concrete code example?


Can someone help me with this figure? I need to add it to a Latex document and I don't know how to use function properly.

I hope to draw a picture like this:    I find it difficult because   Each rectangle is similar in size, with multiple lines of text inside; Some of the upper right corner of the rectangle has some numbers; I can't deal with the four arrows fired from a rectangle IV; Do not know how to locate the rectangle X; I've never drawn this type of graph, no strategy.   Maybe my question violate of the norms of the Forum, but I don't have any other way.


I had ubuntu and Windows 8.1 simultaneously installed on 1 hdd and I Upgraded windows to windows 10, but during the installation, my laptop rebooted and now im stuck  error: no such partition. Entering rescue mode... grub rescue>  I treid the ls command to find the grub files, but it says "unknown filesystem" on all tge partitions

I was dual-booting Windows 7 and Linux Ubuntu on my desktop, and today is the day they gave out free Windows 10 upgrades.  How exciting!  I got the update, and it was installing, and I left to go take a 30 minute nap.  However, when I came back to my computer, it led me to the grub rescue prompt.  error: no such partition. Entering rescue mode... grub rescue>   I get the following when I type ls:  grub rescue> ls (hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1)   After a quick look through of people who encountered the grub rescue prompt, I typed set and got the following  grub rescue> set cmdpath=(hd0) prefix=(hd0,msdos6)/boot/grub root=hd0,msdos6   I was still kind of lost after finding that certain commands like normal didn't work, and then I found a video tutorial where you boot from a Linux image cd and run some commands on the terminal.  Luckily, I had my CD with me, and booted from there.  When I typed sudo fdisk -l into the terminal however, this is what I got:  ubuntu@ubuntu:~$ sudo fdisk -l  Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc03ede74     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT /dev/sda2          206848  1547022335   773407744    7  HPFS/NTFS/exFAT /dev/sda3      1547022336  1547943935      460800   27  Hidden NTFS WinRE /dev/sda4      1547945982  1953521663   202787841    f  W95 Ext'd (LBA) /dev/sda5      1915731968  1953521663    18894848    7  HPFS/NTFS/exFAT   Says here none of my devices has the Linux system in them!  And I couldn't follow the video tutorial any more than that...  I teased my brain a little and determined that sda2 contained my Windows system (since I remember my C: drive has around 700-ish GB of space).  After thinking a little bit more, I remember assigning around 200-ish GB of my hard disk space to something that's Ubuntu related when installing Ubuntu.  I don't exactly remember which, but I think it was basically Ubuntu "hard disk space", and it didn't have any boot files in them.  I assigned two other things for linux, but they were very small in size (not breaking the 1 GB mark yet).  So, can anyone here help me out get my upgrade back on track?  I won't mind if I end up having to completely remove the partitions that have Linux in them.


a recent scan by clamav found that a few exe files in the WINE directory are infected with a trojan (called Ratnim?). A have a few specific questions on what a windows malware can do under linux.  1) Can a WINE malware  (not designed for linux; only designed to run in MS Windows environment) put itself in the system start-up so that it runs everytime i boot the computer?  2)if i were to scan for a WINE program in the process list will i find something to indicated ( like a distinctive icon or a name) to identify it as a WINE application?     3) Can an application running under WINE take screenshots?  4) can an applications running under WINE get hold of my webcam feed? Say when i am in a skype call? (i run linux version of skype if it helps)  i use certain windows applications under WINE on a regular basis. My real concerns are really with points #3 and #4.   I am using ubuntu 14.04 LTS.  Thanks in advance.

Can wine as a whole or the windows applications installed via wine pose some kind of risk to an Ubuntu installation? This question arose in my mind when I read this answer to my earlier question :     Try installing PlayonLinux from   playonlinux.org and install IE via   PlayonLinux. and use IE only for those   pesky sites :) - Received 1 downvote      And enjoying the risks of IE? No   thanks - This comment received 2   upvotes   I believe this PlayOnLinux works as a frontend to wine making installing tasks easier.  In totality, I want to know if it is safe to install Internet connecting applications like IE via Wine? Is there any remote possibility of being subject to more online attacks and virus threats this route. I plan to use IE only for browsing websites not accessible with other browsers, like the one in earlier question.


At the risk of being blasted for cross-posting, I am posting this question again here in the Physics department. It is a duplicate of  in the EE forum. However, I would like to get some answers from more of a Physicist perspective and less of an Engineer. I don't like the fact I have to post it twice either, but I don't know how else to get the right audience to answer it here on StackExchange.  We use them every day and those in the know fully understand the functional characteristics of BJT transistors. There are documents and links galore explaining the operational math. There are even tons of nice videos that explain current theories of how they physically work. ( Most of the latter given by folks that speak "Tele-marketer English" for some reason. )  However, I have to admit, even after 40+ years, a lot of it I have to accept at face value, since the descriptions of how the collector junction fits into the equation is always a bit hand-wavy.   Anyhow, that aside, there is one facet I really just don't get. It seems to defy the laws of physics, Kirchhoff's Laws et.al.  I'm talking about your standard saturated common emitter circuit.  It is known, and we accept, that when saturated, the collector voltage will be less than the base voltage. We obviously use that to our advantage in circuits and chose parts to give us as low a Vce-Sat as possible for a particular load current.     All fine and dandy, till you look at the quintessential mode of a typical NPN transistor...    How the heck can the collector be a lower voltage than the base in that sandwich?   Even if you add in some back-EMF type voltage in there to account for it, the collector current would be going the wrong way through the base-collector junction..    The EE group have some answers that present theories that, to the most part, explain the phenomenon, but some of that theory seems rather conflicting.


I want to know what is the difference between these two examples:  .1 Read a lot of books that are interesting to you.  .2 Read a lot of books that are interesting for you.

I've just caught myself out twice by writing something down as being interesting for me! This is a typical Italian mother-tongue error, but Italian is not my first language. It used to be English, but now I'm no longer sure.   And yet when I say the above phrase it sounds OK. I feel comfortable saying it, so am I right to use the preposition for in this way? If as a linguist said: "Grammar is about how people really speak, not about how they ought to speak."  Here is a  which nicely sums up the difference between interesting to me and interesting for me.     Something you do is interesting for you.         Something people do or say is interesting to you.


Let G be a group in which $(a*b)^3=a^3 * b^3$ and $(a*b)^5=a^5*b^5$ for all $a,b \in G$. Show that G is an Abelian group ?

Let $(G,.)$ be a group and $m,n \in\mathbb Z$ such that $\gcd(m,n)=1$. Assume that $$ \forall a,b \in G, \,a^mb^m=b^ma^m,$$ $$\forall a,b \in G, \, a^nb^n=b^na^n.$$  Then how prove $G$ is an abelian group?  Some context: Some of these commutation relations often imply that $G$ is abelian, for example , or . This looks like another example of this phenomenon, but the same techniques do not apply.


So I have this:  class SimpleDateStructureDemo {    struct Date   {     public int year;     public int month;     public int day;   }    static void Main()   {     ...   }  }   And then I see an example, saying that the object is allocated on the heap:  Date dateMoonWalk = new Date();   I thought that classes are ref type, and structs are value type. In the end, you CAN create a struct type object on the heap by just using new, right?

When you create an instance of a class with the new operator, memory gets allocated on the heap. When you create an instance of a struct with the new operator where does the memory get allocated, on the heap or on the stack ?


I thought I was doing it right but obviously ... not  in C:\Windows\System32\drivers\etc\host  127.0.0.1       myDomain   Question 1 : why doest it work for 'myDomain' (myDomain leads to localhost) but not 'myDomain.com' ? Everytime I add dots to the name, it is not recognized ( is an error)  in Apache conf :  <VirtualHost *:80>     DocumentRoot "C:/wamp/www/myproject/web"     ServerName myDomain ServerAlias myDomain     <Directory "C:/wamp/www/myproject/web">     AllowOverride All     Allow from All </Directory> </VirtualHost>   if I type in a browser : http//myDomain => I am in the documentRoot  but I cannot access directly to what is in the web folder :   Obviously there is something I did not understand, I thought that using the virtual host name (myDomain) I would be in the web folder.  Question 2 : what is wrong ?  Thank you for your help

This is a  about  the use of a *AMPP's stack.    I recently had a talk with some experienced people and they suggested to me not to use a WAMP stack, and instead install apache, mysql and php separately.  I don't understand why they have suggested this, though, so can anyone tell me?  Is there a particular disadvantage of WAMP, or a particular advantage to installing all of them separately?  Since a WAMP stack itself is composed of apache, mysql and php, then what's the difference between using the WAMP stack and installing them all separately?


When I see some good question I'd like to star it and pay attention to its updates (answers, edits, comments). So it's good to see new message from the inbox messages, but it seems that I can only check these questions under my Favorites tab which I forget to do sometimes.  So, is there any way to get other people's question updates in an inbox message? If not, I think I'd like to have this new feature.

EDIT: Summary  I think I've found the best definition of what I want thanks to the discussion with @M. Tibbits:  When I open or refresh the SO, I get a notification of new activities that are of interest to me. Today these are (hard-coded): answers to my questions and comments addressed to me. I want a bit more control over it, that's all.     Yes, I've read  and , but I think I add new (good :) ) reasons for re-asking it:  The first question was answered before this so handy "inbox" notification feature was implemented. So now using favorites for "watching" a question is wrong, IMHO, for 2 reasons:   it splits essentially the same functionality (of getting notified when there is an activity you are interested in) between 2 very different user interfaces it's cumbersome - I need to: 1) add question to favorites; 2) click on my profile dropdown; 3) click on the "favorites" line; 4) see all my favorites with recent activity; 5) select the one I watch; 6) repeat this process occasionally to get updates; and 7) possibly remove the question from favorites at the end. All this as opposed to this little red button when there are news.   Favorites are different in nature that watching. I add a question to Favorites when I find the answers useful to me in my work, so I may want to have it handy in the future. By watching an interesting question I will be able to decide whether I want it in faviorites, after I see the answers.  EDIT: I see that I was not clear enough.  I want to add a question to Favorites when:   it has some good answers the question and answers are relevant in my work I want to keep them handy as my long-term (persistent) knowledge base   I want to watch a question for short while (matter of days/weeks) when:   it is interesting / relevant I want to follow it to see what are the answers. Then I can decide whether I want it in my favorites   As you see, the main differentiators are good answers and long/short term. For short-term, automatic notification is better.  Bottom line, all I ask is "watch this question" checkbox (which may expire after say a week if there is a need to free resources)


import java.util.Scanner;  public class Java3{     int sumAll = 0;     int sumFive = 0;     int sumLast = 0;     int arr[];     int n;          void arraySum(int[] arr) {         for (int i = 0; i < arr.length; ++i) {             sumAll += arr[i];             if (i == 4)                 sumFive += sumAll;             if (i >= (arr.length - 5))                 sumLast += arr[i];         }         System.out.println("sum all  = " + sumAll              + " sum first five " + sumFive              + " sum last five " + sumLast);     }      public static void main(String [] args) {         Java3 obj1 = new Java3();         Scanner scan1 = new Scanner(System.in);         System.out.println("enter the number of elements");         obj1.n = scan1.nextInt();         System.out.println("enter the elements");         for (int i = 0; i < obj1.n; ++i)             obj1.arr[i] = scan1.nextInt();         obj1.arraySum(obj1.arr);      } }  The error I get java.lang.NullPointerException  Errors on Null pointer exception has been asked and answered several times before, but I do not understand those explanations. Can anyone please explain it in a very easy manner. This is my code, and it is showing me the error at runtime. This code is supposed accepts the size of an integer array followed by the integer array. Then calls a function which calculates:  sum of all digits sum of first 5 digits sum of last 5 digits  and prints each value in the console..

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?


Hello AskUbuntu Community I have an annoying problem with my dual boot on my PC.  I have a solid-state drive (SSD) with Windows 10 on it and another one with ubuntu 18.04 LTS.  When I spam my F8 key to show the boot screen, I can boot Windows 10 without any problems. But when I try to boot Ubuntu, I get a black screen, but it should start GRUB in my opinion.  With Ubuntu 16.04.2 LTS it worked very well.  I don't know what I did wrong.  Yours sincerely.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


So when I try to connect to my fav server, I get a response that looks somewhat like this:  Connection Lost Exception Connecting:RuntimeException: Server Is Online Mode!...   I've looked up many tutorials, but I cant seem to be able to find my server.properties folder in order to change this. I found my minecraft folder, but I have no clue what to do from there. I'm on mac computer.

Similar to  on the bugs in Minecraft, I would like a complete list of what error codes exist in Minecraft and how they occur, as well as how they can be resolved.


Some users were being annoying in chat, and they had already been kicked enough to trigger moderation flags. In an attempt to stop them being annoying without annoying the other moderators by proxy, I suspended the user. The "suspend user" dialog box asked for a suspension duration - in hours. Not wanting the suspension to last that long (intending only a 1 minute suspension) I typed in the number 0.01. Then the site crashed. * I assume that this is a bug, and so am reporting it as such. * well, it displayed

I've attempted to suspend a user from chat for 1-2 minutes so I input 0.02 into the "hours" field. The result was


I'm looking for ideas on how to make Settlers of Catan quicker to play between friends. Whenever I play with friends they complain that you have to stop all the time to decide what are you going to do: trade, build, exchange at a port so the game doesn't flow as good as it should. This could be because my friends (and me) don't play board games very much. No one seems to be able to make key decisions quickly. Any ideas/suggestions on how to deal with this issue of slow decision-making? Note: This question, unlike the other, is not about how to "shorten" the game by reducing the required number of moves. This question is about how to shorten the reaction time for a given move.

What are some rule changes that shorten the game, and what drawbacks do those changes have?  Please limit your answers to rules changes with which you have first-hand experience!


I am really interested to have something exactly like this on my Desktop :

Some Windows machines can be configured with a desktop background that will query the local system for its hardware configuration, OS, configuration, statistics, etc.    What program do you need to install to acquire this type of desktop background?


I would like to be able to filter e-mails which are sent to more then, for instance, 15 people? Is something like this achievable? In Outlook 2016?  Or is something like this possible to create using macro's / visual basic with the developer options?  The question is not a duplicate since I ask for a filter, not a warning when I accidently sent an e-mail to +15 people.

I would like to create an Outlook rule that stops me from sending out emails that have more than ten email addresses in the "To:" line. Is this even possible? I'm using Outlook 2010 on Windows 7 64-bit.  My reasoning: I send out a distribution letter to a large number of addresses. I usually send this email to myself with the distribution list addresses in the "BCC:" line. Every once in a while I mess up and accidentally put the distribution list addresses on the "To:" line instead. This is a problem because then each email recipient will see all the addresses on the list. I want Outlook to stop me from doing this, or at least warn me before I send it out.  I also welcome suggestions on how to get around this problem.


A rational number a/b with (a, b) = 1 is called a reduced fraction. If the sum of two reduced fractions is an integer, say (a/b) + (c/d) = n, prove that |b| = |d|.  I am having trouble to understand the solution i found of this exercise:  Note that (a/b) + (c/d) = (ad + bc)/(bd). This is an integer implies bd|(ad + bc), which by linearity implies d|bc and b|ad. However, since (a, b) = (c, d) = 1, this implies that d|b and b|d. Hence |b| = |d|  I don't understand how does the linearity apply here, i mean, it does not make sense to me to use it here. The only things i could conclude is that: $ ad = r$ mod $(bd)$ $bc = bd - r$ mod $(bd)$ Let me know if i am wrong, but linearity is not this?: if $a|m, a|n => a|(k_{1}n + k_{1}m)$ I mean, the solution used in the contrary way, the right side implying the left side. But, even if what the autor of the solutions did is right, why does " bd|(ad + bc), which by linearity implies d|bc and b|ad"?

Assume $x/a$ and $y/b$ are reduced, i.e. $\,\gcd(x,a) = 1 = \gcd(y,b)$. $${\rm if}\ \ \dfrac{x}a+\dfrac{y}b=\dfrac{z}c\ \ {\rm does}\  \dfrac{ab}{\gcd(a,b)^2}\mid c\ ?\qquad$$


I'm designing a logo for an event put on by a non-profit, and I am giving them a really good deal on it as they cannot afford what it is worth. It is a cause I believe in so I would like to help them succeed.  That being said, if they decide to sell merchandise with the logo, would it be inappropriate to expect a portion?  I am thinking of granting rights to all printed and online media, but merchandising rights would be a separate licensing fee (is this how I would word it?).  Would this be alright to put in a contract? I know most logos sign over all-rights, but the client would also pay more for this clause.   Edit: the non-profit is not a charity, and receives funding and grants. They also make quite a bit of money from this event and others, as well as member fees. I am privy to their available accounts and know they can afford to pay, but they don't understand the value of graphic design.  Also, if this question has been asked before, please send me a link. I looked and couldn't find one.

I am fairly new at graphic design and I have just finished creating a logo and marketing materials for a client. I only intended for the images to be used for marketing and advertising of their business, but I'm wondering what kind of rights I have if they randomly decide to try and sell products with the logo.   Is there any way to give my client the rights to use the images for anything they want unless it involves selling items with my designs? If they started selling t-shirts or something, would it be inappropriate to ask for royalties? I keep reading that it is appropriate in this situation to sign over all of the rights to my client since it is their branding materials, but I just don't understand. Has anyone ever had experience with this?   We don't have any sort of contract at the moment (which I now know was a mistake), and I can't seem to find the answer to this question anywhere.


On the left sidebar, the first item of the menu is my profile pic + nickname. It seems to be a fake link. Wouldn't be cool if this link goes to my profile instead of doing nothing?  Or maybe, instead of a "non-link", display a summary of my profile (points, number of badges, profile views, helpful tags, etc..).

Assuming this is on the way, but having not seen it previously reported: I can't view myself from the sidebar, or anyone else by tapping them. View Self From Sidebar:   View Asker/Answerer:   View Commenter:


A fair coin is tossed repeatedly and independently until two consecutive heads or two consecutive tails appear. Find the PMF, the expected value, and the variance of the number of tosses.  Let X be a total number of tosses And it is a problem of geometric distribution.  1)The pmf is clear for me: $ pmf = (1/2)^{k-1}$  The problem is with expected value:  2)My solution: $E[X] = 1/p = 2$  Solution of the book: $E[X] = E[Y] + 1 = 3$  I can't understand the book's solution. How we came to this? I need some explanation. Thanks.

A fair coin is tossed repeatedly and independently until two consecutive heads or two consecutive tails appear. What is the PMF of the number of tosses?


I am trying to prove a rather difficult question and I have arrived at a small proof that I can prove true after thoroughly (and exhaustively) analyzing the group structure.   My question is, if two finite groups have the same number of elements of the same order... are they necessarily isomorphic? If not, what are some properties of the group structure that can show that two groups are necessarily isomorphic?

Suppose $G$ is a finite group and I know for every $k \leq |G|$ that exactly $n_k$ elements in $G$ have order $k$. Do I know what the group is? Is there a counterexample where two groups $G$ and $H$ have the same number of elements for each order, but $G$ is not isomorphic to $H$? I suspect that there is, but I haven't thought of one.


When running systemctl enable my-service  it gets correctly enabled (the link is created into the right WantedBy-target in /etc/systemd/system) but it is not started. However, when rebooting the machine systemd starts the service. What do I need to do to have systemd start the service when enabling the service? For reference, here's my unit-file: [Unit] Description=WebSocket-server-application  [Service] ExecStart=/usr/bin/ws-server.app Restart=always  [Install] WantedBy=multi-user.target  (A little bit of background: systemctl enable is called during package-installation. I need to have the service started once the package has been installed.)

Using one command to both start and enable systemctl managed software would be useful to spare a few lines in a few scripts, making them a bit more aesthetic (not really a problem but a nice thing to have).  Is there one systemctl command to both start and enable a program controlled by systemctl?


I've seen multiple examples of people rolling up a single column into a comma delimited list, but I need a bit more.  Here is an example of the data and results I need.  DECLARE @SalesPerson table (SalesPersonID int, SalesPersonName varchar(10)) DECLARE @Region table (RegionID int, RegionName varchar(15)) DECLARE @SalesPersonRegion table (SalesPersonID int, RegionID int)  INSERT INTO @SalesPerson (SalesPersonID, SalesPersonName) VALUES (1,'Jeff')  INSERT INTO @SalesPerson (SalesPersonID, SalesPersonName) VALUES (2,'Pat')  INSERT INTO @SalesPerson (SalesPersonID, SalesPersonName) VALUES (3,'Joe')   INSERT INTO @Region (RegionID, RegionName) VALUES (1,'North')  INSERT INTO @Region (RegionID, RegionName) VALUES (2,'South')  INSERT INTO @Region (RegionID, RegionName) VALUES (3,'East')  INSERT INTO @Region (RegionID, RegionName) VALUES (4,'West')   INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (1,1) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (1,2) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (1,3) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (2,2) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (2,3) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (2,4) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (3,1) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (3,4)   A simple select will get me each sales person, with each of that salesperson's region.  SELECT      sp.SalesPersonID,     sp.SalesPersonName,     r.RegionName FROM @SalesPersonRegion spr     JOIN @SalesPerson sp         ON spr.SalesPersonID = sp.SalesPersonID     JOIN @Region r         ON spr.RegionID = r.RegionID    In this case, it will return 9 Rows.  I would like to get results like this:  SalesPersonID    SalesPersonName      Regions 1                Jeff                 North,South,East 2                Pat                  South,East,West 3                Joe                  North,West

Consider a database table holding names, with three rows:  Peter Paul Mary   Is there an easy way to turn this into a single string of Peter, Paul, Mary?


Iam using c# vs2010.  For my windows forms project I have some PNG,Gif,Jpg images and I want to use in my program. For that once I added to my resources then is it possible to access from the resorces?  Because after to publish, I don't like, everytime copy to all of my users system for new images.  Is it possible to keep in resources and access it in program without copying to users system?  Thanks For The Ideas...

It's very easy to mark an image file to become an embedded resource however how does one access the image thereafter. Please can I have some example code?


In the attached picture you can find the console of some basic operations in JS, yet I still don't understand how it is not able to identify the object index in the array. Could you please explain it? I am trying to drop an object from an array, whose index is not known. Thank you!

A strict equality operator will tell you if two object types are equal. However, is there a way to tell if two objects are equal, much like the hash code value in Java?  Stack Overflow question  is similar to this question, but requires a more academic answer. The scenario above demonstrates why it would be necessary to have one, and I'm wondering if there is any equivalent solution.


I'd like to scale features with a scale factor. With the scale tool of the editor toolbar it is possible to define a factor but then every single line of the feature is scaled by this factor. However, I'd like to scale the feature referring to the area and not referring to every line (for example 1.5 times the size it was before). Moreover, I'd like to automise the whole process. Does this only work with a python script?

I am writing a python script for ArcGIS 10.3. I know about Scale tool in ArcGIS interface but I can't find such arcpy command. It exists?  As you can see on the picture the Scale tool works different than Buffer tool - it changes the form of original polygon. So the question is:   Can I use Scale tool (available from ArcGIS interface) using arcpy?


I find a C-based language like C# to be better in terms of programming constructs for handling complex code. So has anyone here used SQL simply to extract data and managed their business logic in C++ or C#? How was your experience?   Is it better performance-wise to be doing this?

NOTE The audience of programmers.se and dba.se is different, and will have different viewpoints, so in this instance I think it's valid to duplicate  on programmers.se.  I couldn't find discussion on dba on this already, and the original post says it all, so:     Most software developers want to keep   application logic in the application   layer, and it probably feels natural   for us to keep it here. Database   developers seem to want to put   application logic in the database   layer, as triggers and stored   procedures.      Personally I would prefer to keep as   much as possible in the application   layer to make it easier to debug and   keep the responsibilities of the   layers separate.      What are your thoughts on this, and   what should or should not be ok to   implement in the database layer?   N.B. I'm not the OP for that question, but left the original wording intact.


Travelling via Lufthansa. (Delhi->Frankfurt->Nice)  There would be a waiting time of 6 hours for  my flight from Frankfurt to Nice.    Do I need a transit VISA?  Information from Lufthansa website is not clear.

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


I am taking a course in basics to python and I am stuck on this lab where we have to take the input a full name: ex Pat Silly Doe and print it as Doe, P.S. or in the case they did not input a middle name it would just read: Doe, P. We are only on slicing and formatting strings no if else yet but I feel I am overthinking this I know I need to slice the input and I can do that by: name = input() splitname = name.split(' ') print(splitname)  and that will split each part of the user inputs name up by the whitespaces entered which will then let me know if its 2 names or all 3. But I am kind of lost now as to what to do next. Now that I have the name split up how do I without printing it take each name and format it. I'm not trying to get a direct answer to the lab I don't want to just copy paste code in to do it, I just want a little bump in the right direction.

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


In the comments for , there was a lot of discussion over whether or not a thriller should be considered to be a horror movie.   IMDb classifies  to be a Drama/Horror movie. However,  is classified as a Drama/Thriller movie (and at least one pundit has said that it was   that only got an Oscar because it was able to not be associated with the frequently award-snubbed horror genre). Then there are some movies like  that are both Horror and Thriller.  What exactly is the difference between these two genres? What would cause a movie to be a horror movie, but not a thriller (and vice versa), and what would cause them to be both?  (I imagine that there are film scholars and such who have weighed in on this, and I'd like to see something more authoritative like that instead of just the average Joe's opinions).

The genres, in my opinion, have a very slim boundary separating one from another. I see a lot of movies being categorized as thriller or horror almost interchangeably, which might seem like lack of thought or criteria. However, is there a true criterion used to differentiate between the two film genres?


In the history of sci-fi literature there are examples of technologies predicted in a story (in the sense that a strongly similar to the existent one was present in the tale/novel/book/etc without it been invented yet), is this the case of internet?

Considering the internet has substantially revolutionized our way of life (you're using it right now in fact) I was wondering whether it was ever envisaged in science fiction.  I'm therefore inquiring as to what the first reference in a science fiction story is where there are computers of some description (not necessarily digital, but devices which serve the same functions as computers do for us today) connected with access to the data on each device or to a central server and can communicate via this over long (even global/planet-to-planet) distances.  Basically, what is the first reference in sci-fi to a system like today's internet?


I have just updated to 2.80 from 2.79. When I open a model in which I had some hidden groups they now in 2.80 have the eye icon to show they are not hidden, but they are also semitransparent in the menu. In the scene I don't see any object in the group.  How can I show previously hidden groups etc..?

Whenever I open a blend file that's from 2.79 in 2.8, all of the hidden objects from the blend file are grayed out but I can't unhide them. But other times layers from 2.79 that become collections are having the same problem of being grayed out even though they're not hidden in 2.79. Is this just a bug? I cant find an answer for it anywhere online. They do appear in the render, just not in the viewport window


How to compute the integral $\int_{-\infty}^\infty e^{-x^2}\,dx$ using polar coordinates?

How to prove  $$\int_{0}^{\infty} \mathrm{e}^{-x^2}\, dx = \frac{\sqrt \pi}{2}$$


I downloaded a file .osm. I want to have the same file but with extension .xml To do that, I downloaded osmconverter but the problem is, as states in wikipedia I can convert the .osm file into specific formates and .xml is not one of them.  Please let me know how to do that because I need to do further processing on the file and it must be .xml

I am new to deal with OSM data, and I want to download only .osm files not .pbf. I tried geofabrik.com but it provides .osm.pbf file format   where can I download .osm files? is there any recommended way to convert .osm files to .xml?


I'm traveling to Europe with an engagement ring (€500-€900 value) purchased in my home country, to give it to my European girlfriend. Must I declare it at the airport customs at each country I go through? Must I declare it at the final airport? Or is it considered a "personal use" item? If I will have to declare it in Europe, how much duties and taxes will I have to pay for it?  Details:  I'm a non-EU resident and purchased the engagement ring in my home country. I will give it to my girlfriend in Europe. She is an EU-resident, therefor the ring will remain in Europe after I come back to my home country.  I'm traveling from my home non-EU country. My connecting flights go through multiple countries both in North America and then Europe. The final flight arrives to an EU country from another EU country. I then will drive by car to the final destination country which is also in Europe.

In , MikeV posted a pertinent question which is worth asking:     If I buy a ring in the US, put it in my bag and do not declare the ring I am smuggling jewelry? How is that different from buying the ring, wearing it round my neck on a chain (or on my own finger for that matter) and not declaring it? Am I supposed to declare my own jewelry that I already paid for (including taxes upon purchase)?   So, what is the verdict on this? smuggling or not? And is it a difference whether it's on a finger, on a neck chain, or in a box in the carry-on?


I have a high rise detailed model and I wish to bake the high poly textures to a low poly model version of the building

I understand that one uses normal baking to bake the normals of a high-resolution (sculpted, in the millions-of-polys range) to an image, which are then set to the normals of the low-resolution (retopologized, in the thousands-of-polys range) mesh to create the illusion of higher resolution, as shown in the following image from Wikipedia:    To save the normal of each vertex to an image, the mesh would have to be UV-unwrapped. However, as I understand it, the entire purpose of retopologizing is to get good topology that can be used for UV-unwrapping. Even if you unwrap the high-resolution mesh, how do you unwrap the low-resolution mesh with the exact same configuration, such that the normals are projected properly?  Or, phrased more succinctly:  What exactly is the workflow for sculpting, retopologizing, and normal-baking?


When asking questions on Math.SE, the "MathJax help »" link on the sidebar points to , which in my opinion is very friendly to users who have never heard about MathJax before.  However, on many other sites, the help link points to , which seems to be too complete for new users.  Due to its brevity and helpfulness, I think we should use  as a crash course on all SE sites, maybe after immigrating this post to Meta Stack Exchange if necessary.    Actually, I've found , but after nearly 2 years, it received 0 answers and even 0 comments. Also, that post consider this problem a "bug", but I think it should be a "feature request". This is why I'm posting my own question now.

When editing a post on a site where MathJax is enabled there in "how to format" there is a link  which points to a page not as useful as the  on .  So I suggest to replace that link with


For some reason I can boot and either use Ubuntu 12.04 server edition, or desktop version.  I can live boot the disk, I can go through the installer, or even use the ubuntu alternate installer. But for some reason after the install completes and I reboot the monitor seems to go back into sleep mode and then never loads the command prompt.  This is on an industrial adlink MXE-1300 PC.  I've installed ubuntu server fine on other models of adlink machines but this one doesn't want to seem to play nice.  To me it seems like if it was a video card issue than I could never even load the installer or run ubuntu in live mode.  Any thoughts or troubleshooting tips would be greatly appreciated.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


I'm trying to define "#1" as \text{#1} in math mode.  This worked:  \catcode`` = 13 \def``#1``{\text{#1}}   But if replace `` with ", it fails. I don't understand why. Is it possible to define " in this way ? And it possible to let this only work this way in math mode ?

Is there a way to use newcommand or some other nice technique to transform any occurence of  "bla"   in math mode into  \text{bla}   The reason I ask is because it is easy, and doesn't interrupt the flow of reading the (La)TeX code as much.  I would like to keep Xe(La)TeX's nice quote behavior (ie it can use the regular "" instead of backticks to quote some text outside math mode).


$$\sum_{k=n+1}^{2n}\frac{1}{k}$$ We would like to approximate this sum using Riemann integral. My approach is following: Let $f:[n+1, 2n]\to \mathbb{R}$, $f(n)=\frac1n$. Let $P=(x_0, x_1,..., x_n)=(n+1, n+2, ..., 2n)$ Then $$\sum_{k=n+1}^{2n}\frac{1}{k}=\sum_{i=1}^{n}f(x_{i+1})(x_{i+1}-x_i)=\sum_{i=1}^{n}f(x_{i+1})$$ So, we have that $$\sum_{k=n+1}^{2n}\frac{1}{k}\to \int_{[n+1,2n]}\frac1xdx$$     I am not sure if I am ok, help me please understand these issues.

What is the sum of the 'second half' of the harmonic series?  $$\lim_{k\to\infty}\sum\limits_{n=k+1}^{2k}{\frac{1}{n}} =~ ?$$  More precisely, what is the limit of the above sequence of partial sums?


I have watched video on   when a man exhibits  conductivity through his body. But how much current can a human conducts safely?   Is there any trick?   I have heard from a man who said that " I'd like to see him connect one wire to his left foot and the other to his right arm. It'll make current pass through his heart. Just a thousandth of an amp passing through any human being's heart can kill them."  How true is that?

I just wanted to learn some differences between volts, amps, ohms and so forth and came up with this question. If your skin has 100k ohms resistance and the outlet is 220v wouldn't the current flowing through your body be 0.0022 amps?


What is the correct way to say:  There are in total 485 devices spread over 46 accounts.  or   There is a total of 485 devices spread over 46 accounts.

Which one is the correct one?        A total of 10 babies is sleeping. (A)   A total of 10 babies are sleeping. (B)   Ten babies in total are sleeping. (C)      For me, both (A) and (C) are correct. But (B) is also used in speech.


I have a PHP script with this code:  $sid = $_COOKIE['sid']; $q = mysql_query("SELECT * FROM `order` WHERE `sid` = '$sid' AND `use` <> 1");   In a MySQL table with name users, I have the following columns: id, name, md5password.  How can I do:   UPDATE `users` SET `md5password` ='newpassword'`   with a potential SQL injection in PHP? Can you give me an example?

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


I have a question relating to passing an undeclared String to a Function.  The code below compiles and works correctly (in that the string is correctly printed). I'm trying to understand the details of how the code works with respect to memory allocation (does the compiler generate a Temporary variable from the "String" and actually pass that to the Function?).  Normally I would declare a char array to hold the String and then pass that to the function - that makes sense in terms of memory allocation.   I'm specifically looking to see if there are any gotchas with respect to memory leaks if strings are passed directly as per the program below (e.g. a long running program passing lots of Strings to a Log - does each string pass create some sort of new string variable whose memory is never released etc).   Code - Compiles in Visual Studio 2013  #include <stdio.h>  //Function Declaration int MyFunction(char *SomeString);   int main(void) {     MyFunction("MyString");     return 0; }   //Function Code int MyFunction(char *SomeString) {     printf("Passed String: %s \n", SomeString);     return 0; }

Are the string literals we use inside functions automatic variables? Or are they allocated in heap which we have to free manually?  I've a situation like the code shown below wherein I'm assigning a string literal to a private field of the class (marked as ONE in the code) and retrieving it much later in my program and using it (marked as TWO). Am I assigning a variable in the stack to a field in ONE? Can the code be referencing to a dangling pointer which in this case worked because the program was small enough?  I've compiled and ran it, it worked fine but I'm having a strange crash in my actual program where I'm assigning string literals to fields of the class like this and I suspect the case I mentioned above.  #include <iostream>  using namespace std;  class MemoryLeak { private:     char *s; public:     MemoryLeak() {}      void store()     {         s = "Storing a string"; // ONE     }      char *retrieve()     {         return s;     } };  int main() {     MemoryLeak *obj = new MemoryLeak();     obj->store();     cout << obj->retrieve() << endl; // TWO     delete obj;     return 0; }   Should I be declaring the variable "s" as a char array instead of a pointer? I'm planning to use std::string, but I'm just curious about this.  Any pointers or help is, as always, much appreciated :) Thanks.


Let L = {w| w ∈ {a,b,c} * is palindrome} Could someone explain me how to prove that L is not regular, because all answers I've found are done with 2 symbols(a,b), and I'd need to prove it with 3.

Firstly I pick a language $xyz$ where $x = \epsilon$, $y = (abb)^{k}$, $z = (bba)^{k}$ where $|y| \ge$ the number of states in the automaton representing my language. Then $xyz = (abb)^k(bba)^k$ is a palindrome.  Now I split $y$ into $uvw$, where $v \ne \epsilon$ contains a state visited more  than once. If the language is regular then $xuv^iwz$ is within the language $\forall i \ge 0$.  I choose $i = 2$, then $uv^2w = (abb)^n$ where $n > k$.  Then $xuv^2wz = (abb)^n(bba)^k$ where $n > k$, which is not a palindrome.   Firstly, is my reasoning for this particular proof correct?  I'm unsure about how to properly apply the pumping lemma to this problem. And secondly the question asks me to state a proof for palindromes in general, whereas I only attempted to prove it for a single case. Is there an example I can choose which proves the conjecture for all palindromes? I assume not, seeing as I can't think of how that could be represented using regular expressions.


For a Gaussian kernel, what is the  sigma value, and how is it calculated?   $K(\mathbf{x}_i,\mathbf{x}_j) = \exp{-\frac{\|\mathbf{x}_i-\mathbf{x}_j\|^2}{\sigma^2}}$ ?  Is it the covariance of the entire data set?

have a couple of coefficients which meaning I can not understand.  gamma : float, optional (default=0.0) Kernel coefficient for ‘rbf’, ‘poly’ and ‘sigmoid’. If gamma is 0.0 then 1/n_features will be used instead.  and  coef0 : float, optional (default=0.0) Independent term in kernel function. It is only significant in ‘poly’ and ‘sigmoid’.  I tried to google for gamma in support vector machines, but have not found anything relevant. Can anyone explain me what is the meaning of these parameters and reasonable value for them.


Why does this  log rule make sense:  $$ \log(x)^{1/2}= \frac{1}{2} \log x?$$  I can see why this makes sense:  $$\log x^4=4\log(x)$$  But I can't really make sense of why this works. Like why does:  $$log_24^3=3 \log_24 $$  This is a problem I am having trouble finding the derivative for:  $$H(z) = \ln \sqrt{\frac{a^2-z^2}{a^2 + z^2}}=\frac{1}{2}\ln \frac{a^2-z^2}{a^2 + z^2}=\frac{1}{2} \ln(a^2 - z^2) - \ln(a^2 + z^2)$$  right?  so:  $$H'(z) = \frac{1}{2} \cdot \frac{1}{a^2 - z^2} \cdot -2z - \frac{-1}{a^2 + z^2} \cdot 2z$$  $$ = \frac{-2z}{2(a^2 - z^2)} - \frac{2z}{a^2 + z^2}$$  Is this right?

I'm having trouble seeing number 3 clearly. Or rather, I'm having trouble seeing a proof. I've tested a series of numbers and it works, but I'm having trouble seeing why. Can anyone clarify?    Here is where I get confused:  I start with this log:  $$ \log_2 4^1 = 2$$  now if I raise both sides to the 2nd power then:  $$ \log_2 4^{1^2} = 2^2$$ $$ = \log_2 4^2 = 4$$ $$ = 2 \cdot \log_2 4 = 4$$  but if I raise both sides to the power of 1.5 then: $$ \log_2 4^{2 \cdot 1.5} \ne 4^{1.5} \ne 8$$


I am trying to define a command that writes the word "FACTORING" in sans serif. I did define the command as follows:  \newcommand{\FACTORING}{\textsf{FACTORING}}  But the when I use the command "FACTORING" does not have any distance to the following letters (see the following small document.) Could you please tell me what I am doing wrong?  \documentclass[a4paper, 11pt, oneside]{book}    \makeatletter \makeatother \usepackage[a4paper,left=3cm,right=3cm,top=3cm,bottom=3cm]{geometry}   \usepackage[style=numeric,firstinits,sorting=none]{biblatex}   \usepackage{etoolbox} \usepackage{fancyhdr} \usepackage[T1]{fontenc} \usepackage{graphicx} \usepackage[utf8]{inputenc} \usepackage{latexsym} \usepackage{lmodern}    % The Font Type \usepackage{mdframed} \usepackage{titlesec} \usepackage[absolute,overlay]{textpos}  \newcommand{\FACTORING}{\textsf{FACTORING}}     \begin{document}  ssssssssssssssss \FACTORING aaaaaa.  \end{document}

I have a definition:  \newcommand{\arnold}{Arnold Schwarzenegger}   When I refer to it by:  \arnold is a   it is rendered as:   Arnold Schwarzeneggeris a    In order to have a space in front of "is" I would need to write  \arnold\ is a   Is there some other shorter way?


How do I reorder the rows of the shapefile in the file? I know how to order them in the attribute table view, but I need to actually switch up the order (by descending id) in the file itself.  It's a little weird but the reason being eventually it will be turned into a geojson and drawn up in a webmapping project but the way the webmapping API works, the draw order is naturally in the order that is in the file, and when icons get very clustered, I'd like items with the lower id to take priority (e.g. be on top / drawn last).  There's probably a way around that in the webmap API but I think it'd just be much simple to reorder the table.

I've written a  which produces a polygon shapefile of the extents of all the thousands of rasters in our library. I want to organise the FID so that the files with the largest extents are on the bottom so that an area of interest can be easily selected.  By organise FID - i mean that the layers should be drawn (in the shapefile) from the smallest extent to the largest extent as otherwise (like in layer ordering) the record of the dataset that has the highest FID will get selected over anything below it. This is not a simple (temporary within map/layer) sort but it has to be to permanently change the order in which the rows are written into the shapefile.


I'm having some issues with my laptop's onboard Wi-Fi running under Ubuntu 16.04 LTS. Previously it ran fine, but now it's having some issues and I'm a bit lost. The WiFi card seems to be unable to be used under the Linux environment, but is fully functional under Windows. I've added some screenshots at the end and would be grateful for any help.  The wireless card in question is a Broadcom BCM4352.  Steps taken so far:   Turning laptop off and on Disabling and enabling the Wi-Fi card under the Additional Drivers tab Testing connection with USB Wi-Fi dongle (Worked successfully) Testing internal Wi-Fi card under Windows (Worked successfully)   Here are some screenshots showing where I'm at:   I'd be very grateful for any help

This issue happens only on UEFI systems with enabled Secure Boot.  When I try to install DKMS modules like VirtualBox, Nvidia, or Broadcom drivers, they do not install and I get Required key not available when I try to modprobe them.  VirtualBox complains that vboxdrv is not loaded.  Broadcom wl driver is shown in lspci -k as a kernel module but is not in use. sudo modprobe wl throws Required key not available.  Also this issue may happen when I install some kernel modules from git sources.  This issue may appear after a kernel update as disabled wireless adapter, black screen after a reboot, etc.   How can I fix it?


Depending on the submission journal, there may be some explicit rules allowing or forbidding the posting of a preprint before the peer review process is complete. However, for those journals that don't forbid it, is there any evidence that doing so impacts negatively on the prospects for acceptance?

The recent question  made me realize that I don't have any understanding of why one would upload to a preprint site.  (I don't work in a field where they seem to be common.)  Why would one be concerned about getting a manuscript on arXiv, if it's already under review with a journal?   Is it because of the long publishing timeline of journals?  (That could explain why computer science — which publishes much more in conferences — doesn't seem to do much with them.)


I have an audio interface device and it has a power supply requirement at 9V DC 3.5A. The original power supply adapter that came with it was 9V DC 4A. Can I replace this with an adapter rated for 9V DC 5A with no risk to the interface device?

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


Is it possible to flash a ruu on a rooted HTC One X (Evita).  Actually, I have a AT&T HTC One X (evita) and I want to flash with an international rom of HTC One XL. It will be good if any one know a link of rooted stock rom of HTC One XL international version.  I am no more using AT&T and dont want any AT&T apps.

There are several reasons to be looking for a ROM:   Upgrading or downgrading your stock ROM Looking for firmware from a different region/language Flashing a custom ROM for different features, removing bloat, etc.   But where can one find ROMs in the first place?  What sites are likely to have the ROM I need?  ; please add to the wiki answer instead of posting separate answers.  See also:


How do I find this?   I know that I should use perhaps:   $gcd(a,b) = gcd(a,a-b) $  But then I get:   $gcd(15570555,4697976) $   Which seems still too large for me to do anything further.

Are 15,462,227 and 15,462,229 relatively prime?   How do I construct a proof for this.   I know that for n and n+2 to be relatively prime it is the case that n has to be odd. Is this the only requirement for these numbers to be relatively prime?


Quick question:   Is it possible to use "mkdir" to make a new directory AND change to that directory at the same time using a single 'mkdir' command?  Whole question:  I have this question:  What single Linux “mkdir” command could replace the sequence of commands?          mkdir a          cd a          mkdir b          cd b          mkdir c          cd ../..   My answer is:           mkdir a b c && cd c   Is there a single "mkdir" command, without using any other commands, perhaps with some flags or something, I can use to make AND change directory at the same time?

is there any way (what is the easiest way in bash) to combine the following:  mkdir foo cd foo   The manpage for mkdir does not describe anything like that, maybe there is a fancy version of mkdir? I know that cd has to be shell builtin, so the same would be true for the fancy mkdir...  Aliasing?


In countless episodes of Star Trek incarnations, characters using the replicator for food state that "the replicator hardly does this justice", "this replicated [food item] never tastes quite right" all the way down to "why would you eat such replicated swill!"  So what is wrong with replicators? Based on my limited knowledge of the fictional device, the thing uses molecular definitions of food (or food components) and presents it. Does it add something to give it that certain artificial something to allow you to crave your Aunt's original recipe? Or are the people who say these things just food snobs?

are used ubiquitously throughout the Star Trek universe to produce any material that the user desires - notably food and drink.  On a starship, the crew's entire diet would consist of replicated food matter.   However, replicated matter is known for having innate flaws.  This is why rare materials and living intelligent creatures cannot be stored and replicated at a whim - the matter involved is too complex.  Yet in all matter, including that which is replicated for consumption, these atomic errors persist.    Has there ever been an instance of or suggestion that a diet of replicated food and drink may have an adverse effect on a person?


I'm wondering if there is a difference between an asymptotically unbiased estimator and a consistent estimator.   For asymptotically unbiased estimators, the expected value of the estimator converges to the parameter, while for a consistent estimator, the estimator converges in probability to the parameter.   These sound nearly identical, but I believe that being consistent might actually be stronger than being asymptotically unbiased, since being consistent, i.e. converging in probability, implies that not only will the estimates be roughly centered around the true value, but will also be getting closer to it as n increases.   Can someone confirm or refute this claim?

Does each imply the other? If not, does one imply the other? Why/why not?  This issue came up in response to a comment on an answer I posted .  Although google searching the relevant terms didn't produce anything that seemed particularly useful, I did notice  on the math stackexchange. However, I thought that this question was appropriate for this site too.  EDIT after reading the comments  Relative to the math.stackexchange answer I was after something more in depth, covering some of the issues dealt with in . Also, as I see it the math.stackexchange question shows that consistency doesn't imply asymptotically unbiasedness but doesn't explain much if anything about why. The OP there also takes for granted that asymptotic unbiasedness doesn't imply consistency, and thus the sole answerer so far doesn't address why this is.


I have a directory, under /srv:  drwxrwxr-x  3 minecraft minecraft 4096 Dec 30 06:23 minecraft  Owned by user minecraft, group minecraft. Group has read/write/search permissions. I have a user, shelvacu, that is part of the minecraft group:  $ groups shelvacu shelvacu : shelvacu sudo minecraft   And, as shelvacu, I run mkdir /srv/minecraft/testdir:  $ mkdir /srv/minecraft/testdir mkdir: cannot create directory ‘/srv/minecraft/testdir’: Permission denied   Why? The minecraft group has write permission on the directory, and shelvacu is part of the minecraft group. What am I missing?

I changed permissions of a file (chmod g+w testfile) and running ls -l testfile gives:  -rwxrwxr-x 1 user1 user1 0 2011-01-24 20:36 testfile   I then added a user to that group ("/etc/group" has user1:x:1000:user2 line), but am failing to edit that file as user2. Why is this so?


Where does the "inertia" term in regard to quadratic forms (e.g. Sylvester's law of inertia) come from?  Thank you!

By "Sylvester's Law of Inertia," I mean:    How does the name "Law of Inertia" fit with the statement of the theorem? I guess it's from physics, but... I just don't see the connection.


I thought this would be a simple thing to find, but all the documentation deals specifically with either creating an Apex web service, or accessing the SF REST API in some general way - but what about accessing a custom Apex web service?   To be more clear, when a developer creates a post request to an Apex web service, what do they include in the headers or body of that post request so that they are able to access the Salesforce endpoint?  For example, one might make a request to a custom SF web service like this:  HttpRequest request = new HttpRequest();      request.setEndpoint('https://yay.my.salesforce.com/services/apexrest/CreateDOService/v1'));      request.setMethod('POST');      request.setHeader('Content-Type', 'application/json;charset=UTF-8');      request.setHeader(Does some token go here? How do I get it?);      request.setBody('{"Event":"Thing Returned"}'); HttpResponse response = http.send(request);   What else needs to be included?  I see references to OAuth 2.0, SessionIDs, and connected apps in the documentation below, but I can't find any actual examples of code that uses these things. Once I create a connected app for an external application, how do I tell the developer of that application to use the connected app? What kind of code do they need to write?       Many thanks for any code examples you could provide.

I've been trying to read through the SalesForce documentation on how to call a custom Method like this via cURL:  @RestResource(urlMapping='/Test/*') global with sharing class RestTest  {     @HttpGet     global static Account getAccount()     {         Account a = [select Id, Name from Account WHERE Name = 'wizzbang' limit 1];         return a;     } }   My gut tells me this should be something as simple as:  $ curl -i -H "Accept: application/json" -H "Content-Type: application/json"  -X GET https://mydomain.salesforce.com/services/apexrest/test/   But I get back that this is unauthenticated. I've gone through the guide and it says I have to setup a "connected app." I've done this...I think. But I'm not sure what my CallbackURL should be? Further, I don't get what I need to make my curl statement look like in order to call the service? Can someone explain what I need to do? This seems horribly overengineered.


Find the Cauchy-Riemann equations in polar form. In other words, if $f(re^{i\theta}) = u(r,\theta)+iv(r, \theta)$, then find the relations for the partial derivatives of $u$ and $v$ with respect to $f$ and $\theta$ if $f$ is complex differentiable.      Hint: the following version of the chain rule for partial derivatives may be useful:   $$\frac{\partial u}{\partial r}=\frac{\partial u}{\partial x}\frac{\partial x}{\partial r}+\frac{\partial u}{\partial y}\frac{\partial y}{\partial r}$$   Further, Use the polar version of the Cauchy-Riemann equations to verify that $f(z)=z^n$ is analytic in $\mathbb{C}$ for any $n \in \mathbb{N}$, and that the principal logarithm is analytic in $\mathbb{C} \setminus \{ z \leq 0\}$.  I'm pretty unsure of where to start on this one. Thanks for your help!

Show that in polar coordinates, the Cauchy-Riemann equations take the form   $\dfrac{\partial u}{\partial r} = \dfrac{1}r \dfrac{\partial v}{\partial \theta}$ and $\dfrac{1}r \dfrac{\partial u}{\partial \theta} = −\dfrac{\partial v}{\partial r}$.      Use these equations to show that the logarithm function defined by   $\log z = \log r + i\theta$ where $z=re^{i\theta}$ with $-\pi<\theta<\pi$ is holomorphic in the region $r > 0$ and $-\pi<\theta<\pi$.   What I have so far:   Cauchy-Riemann Equations: Let $f(z)$ = $u(x, y)$ +$iv(x, y)$ be a function on an open domain with continuous partial derivatives in the underlying real variables. Then f is differentiable at $z = x+iy$ if and only if $\frac{∂u}{∂ x}(x, y)$ = $\frac{∂ v}{∂ y}(x, y)$ and $\frac{∂u}{∂ y}(x, y)$ = −$\frac{∂ v}{∂ x}(x, y)$. So we have $f'(z)= \frac{∂u}{∂ x}(z) +i \frac{∂ v}{∂ x}(z)$. Let $f(z)$ = $f(re^{iθ})$= $u(r,θ)$ +$iv(r,θ)$ be a function on an open domain that does not contain zero and with continuous partial derivatives in the underlying real variables. Then f is differentiable at $z$ = $re^{iθ}$ if and only if $r \frac{∂u}{∂r}=\frac{∂ v}{∂θ}$ and $\frac{∂u}{∂θ}$ = $−r \frac{∂v}{∂ r}$.  Sorry, if this is not very good. I just decided to start learning complex analysis today...


I am trying to write a new enviroment to add text into a \fbox, when I use \fbox on its own, it works quite nicely  \fbox{\begin{minipage}{0.9\textwidth} does this work, I would love if it did \end{minipage}}   If I then add this into a new comand called notes Latex dosen't seem to like it  \newenvironment{notes} {\fbox{\begin{minipage}{0.9\textwidth}}} {\end{minipage}}   When I then enter something into this environment in my document it comes up with errors  \begin{notes} Does this work, I would love if it did \end{notes}   The error I recieve is:  ! Extra }, or forgotten \endgroup. \fbox ...xsep {#1}\kern \fboxsep \color@endgroup } \@frameb@x \relax  l.80 \begin{notes}  ?

This question is a direct follow-up to the question  I asked yesterday.   The following example is once again a counter-intuitive one, to demonstrate what I wish to achieve. I'm trying to split the parbox syntax across the begin code and end code of a newenvironment. Using begingroup and endgroup does not seem to work here, and is producing an error.  \newenvironment{mybox}{\parbox{10cm}\begingroup}{\endgroup}   Is this possible in LaTeX?  Just to elaborate a bit on my specific need, I need a lot of centered, framed boxes to highlight some "warnings" and "best practices". For this, I thought of the following environment:  \newenvironment{mybox}[2]% {%   \begingroup \centering \fbox \begingroup \parbox{10cm} \begingroup #1 \hspace{5pt}   {\large \textbf{\textsf{#2}}} \hfill \\ }% {%  \endgroup \endgroup \\ \endgroup \vspace{5pt} % }   One of the arguments is for switching between the texts "Warning" and "Best Practices", and the other one is to provide a special symbol for each type (like a star or as shadowed box)


How should I check any git commit done in remote git branch and generate an email after any code is checked in to remote repository while working on local branch so that any merge conflict can be avoided.

How do I configure the appropriate Git hook to send a summary email whenever a set of changes is pushed to the upstream repository?


I am relative new user and i like ubuntu based distros (since i can google everythng up and make it work without overheating my brain) and i was wandering what ubuntu based distro would you recommend for me (since my plan is to switch completely to linux and use it as main OS on my PC) my PC configuration is  >>> AMD Athlon 64 x2 Dual Core 4200+  2.19GHz >> 2GB RAM >>> Nvidia GeForce 8400 GS.I did tryed a lot of dystros and first question alwayse is should i download 32bit or 64 bit since i have 64 bit CPU but only 2 GB ram  O.o  Ubuntu somehow since 10.01 LTS (was the latest perfectly working version) wasnt working good on my machine and i dont know why...So 32but or 64bit ubuntu based distro and what distro for my PC. Thank you.

What is the difference between 32-bit and 64-bit Ubuntu? I've heard the 64-bit platform performs better and can detect more than 4GB of RAM. Also, while some apps haven't ported to 64-bit yet, ia32-libs lets a 64-bit machine run them.  If so, why not promote 64-bit over 32-bit?


sudo echo "sadfsadf" > /etc/apache2/mods-available/dir.conf  I ran the command with sudo but it returned the error: "permission denied:  Why does this command not work?

This is a pretty simple question, at least it seems like it should be, about sudo permissions in Linux.  There are a lot of times when I just want to append something to /etc/hosts or a similar file but end up not being able to because both > and >> are not allowed, even with root.  Is there someway to make this work without having to su or sudo su into root?


Google returns that response, not sure why is a complex number.

How do I derive:   $\ln(-1)=i\pi$ and   $\ln(-x)=\ln(x)+i\pi$  for $x>0$ and  $x \in\mathbb R$  Thanks for any and all help!


I'm new at PHP, so if there's some kind of advice, it will be well received.  I want to concat all the results I get from a sql query to my database.  I got the code:  $sql = $_POST['sql']; /*sql query*/ $result = "";  $query = mysqli_query($conn, $sql); while ($row = mysqli_fetch_array($query, MYSQLI_NUM)) {   $result = $result . ' ' . $row; }  echo $result;   What I want is not a sql query that concats, but a way to concat rows with PHP.

Using MySQL, I can do something like:  SELECT hobbies FROM peoples_hobbies WHERE person_id = 5;   My Output:  shopping fishing coding   but instead I just want 1 row, 1 col:  Expected Output:  shopping, fishing, coding   The reason is that I'm selecting multiple values from multiple tables, and after all the joins I've got a lot more rows than I'd like.  I've looked for a function on  and it doesn't look like the CONCAT or CONCAT_WS functions accept result sets.  So does anyone here know how to do this?


Is there a way to render my Partial View to String or Html? and used that to convert to PDF?  I guess, the only item I need to accomplish is to Render my Partial View to String or HTML, if it's possible.  I already have a tool that can get .htm/.html files and convert it to PDF.  Thank you.

I want to output two different views (one as a string that will be sent as an email), and the other the page displayed to a user.  Is this possible in ASP.NET MVC beta?  I've tried multiple examples:  1.      If I use this example, I receive the "Cannot redirect after HTTP   headers have been sent.".   2.      If I use this, I seem to be unable to do a redirectToAction, as it   tries to render a view that may not exist. If I do return the view, it   is completely messed up and doesn't look right at all.   Does anyone have any ideas/solutions to these issues i have, or have any suggestions for better ones?  Many thanks!  Below is an example. What I'm trying to do is create the GetViewForEmail method:  public ActionResult OrderResult(string ref) {     //Get the order     Order order = OrderService.GetOrder(ref);      //The email helper would do the meat and veg by getting the view as a string     //Pass the control name (OrderResultEmail) and the model (order)     string emailView = GetViewForEmail("OrderResultEmail", order);      //Email the order out     EmailHelper(order, emailView);     return View("OrderResult", order); }   Accepted answer from Tim Scott (changed and formatted a little by me):  public virtual string RenderViewToString(     ControllerContext controllerContext,     string viewPath,     string masterPath,     ViewDataDictionary viewData,     TempDataDictionary tempData) {     Stream filter = null;     ViewPage viewPage = new ViewPage();      //Right, create our view     viewPage.ViewContext = new ViewContext(controllerContext, new WebFormView(viewPath, masterPath), viewData, tempData);      //Get the response context, flush it and get the response filter.     var response = viewPage.ViewContext.HttpContext.Response;     response.Flush();     var oldFilter = response.Filter;      try     {         //Put a new filter into the response         filter = new MemoryStream();         response.Filter = filter;          //Now render the view into the memorystream and flush the response         viewPage.ViewContext.View.Render(viewPage.ViewContext, viewPage.ViewContext.HttpContext.Response.Output);         response.Flush();          //Now read the rendered view.         filter.Position = 0;         var reader = new StreamReader(filter, response.ContentEncoding);         return reader.ReadToEnd();     }     finally     {         //Clean up.         if (filter != null)         {             filter.Dispose();         }          //Now replace the response filter         response.Filter = oldFilter;     } }   Example usage  Assuming a call from the controller to get the order confirmation email, passing the Site.Master location.  string myString = RenderViewToString(this.ControllerContext, "~/Views/Order/OrderResultEmail.aspx", "~/Views/Shared/Site.Master", this.ViewData, this.TempData);