I read .  However this only shows the flags I've done on comments. I've flagged questions voted questions to be closed as duplicates, but I don't see them!  I do some of them, but not the last few months:    Even though today, I marked  as a duplicate...

Is there a section or page that lists my flag count and / or history?


Is there anyone who can tell me by looking at some setting from my laptop if I have spywear installed or being remotely controlled what do I have to check for please advise how I find out if I am being remotely controlled or monitered TIA ps please expline in simpelist terms any help or answer im not very good or technical on this sort of subject its driving me crazy will be very gratefull for any help thank you also how I set up surface pro to be complete admin and max security

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


Please if you know how to solve this: I need to add nested lists, each list with randomly generated numbers, but within the same range. If I run my code like it is, it adds nested lists, each list with the correct length of 6 numbers, but the problem is that all numbers in the lists are identical! the output is like that: [     [27, 2, 23, 12, 9, 2, 28, 31],     [27, 2, 23, 12, 9, 2, 28, 31],     [27, 2, 23, 12, 9, 2, 28, 31],     [27, 2, 23, 12, 9, 2, 28, 31] ]  How can I manage to generate new numbers each time I call the function in the for loop? lottery_numbers = [] numbers_list = []  def num_generator():    for num in range(0, 2):       random_number = random.randint(1, 40)       numbers_list.append(random_number)       lottery_numbers.append(numbers_list)     for number in range(0, 4):   num_generator()

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I have a problem because i add html through jquery. So when i click on remove button i dont get alert. Any suggestion how can i fix that?  $(document).ready(function() {   var max_fields      = 10; //maximum input boxes allowed   var wrapper         = $(".input_filelds_main_wrapp"); //Fields wrapper   var add_button      = $("#addNewIframe"); //Add button ID    var x = 1; //initlal text box count   $(add_button).click(function(e){ //on add input button click       e.preventDefault();           html = '
';           html += '

';           html += 'TITLE ';           html += '<input type="text" name="iframe_title[]" class="form_input iframe_title" />';           html += '
';           html += '
';           html += 'IFRAME';           html += '<textarea name="view360[]" class="description_property view360s"></textarea>';           html += '

';           html += '<input type="hidden" class="view360_id" value="undefined" />'           $(wrapper).append(html);   });    $('.remove_field').click(function(e){ //user click on remove text       alert('aaaa');       e.preventDefault();       e.preventDefault(); $(this).parent('div').remove(); x--;   }) });

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


I'm trying to learn JS and got an issue. I tried many things and googled but all in vain. Following piece of code doesn't work as expected. I should get value of i on click but it always returns 6. I'm pulling my hair out; please help. for (var i = 1; i < 6; i++) {      console.log(i);      $("#div" + i).click(         function() {             alert(i);         }     ); }

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


Is there a non-parametric closed form for a function looking like a sine rotated 45 degrees?  I have encountered also a  but it asks for a function resembling the rotated sine, but not necessarily exact.

I need to be able to plot pixels in this pattern. To me, it looks like a sine wave pattern that is both diagonal and convergent.      What would a function for that look like?  Thanks.


I have a notification that someone commented on one of my questions, and the notification will not go away no matter what. It appears across the whole network, of course. If I click through to go to the page the comment is on (a question posted on SO), the notification is there waiting to take me to the page a second time! It's infinitely recursive!  Kind of a nasty bug actually, very annoying.

This was asked before too. .  Currently I am facing the issue of appearance of reputation notification in above toolbar.  I can see the reputation notification, for every page refresh even after clicking and viewing the notification.  current browser: Chrome Version 36.0.1985.143 m


i have this method to serialize my objects :      private static byte[] GetBytes(object obj) {         byte[] result;         using (MemoryStream ms = new MemoryStream()) {             DataContractJsonSerializer ser = new DataContractJsonSerializer(obj.GetType());              ser.WriteObject(ms, obj);             result = ms.ToArray();             ms.Close();         }         return result;     }   it is normal, when i want to use this, my object parameter must a class that decorate with [System.Runtime.Serialization.DataContract] and its member must decorate with [System.Runtime.Serialization.DataMember] but how about when i want to use unknown type like :  var myVar = GetBytes(new { Name = "MyName", LastName = "LastName" });   how can i decorate unknown types with attribute

I'm attempting to use the following code to serialize an anonymous type to JSON:  var serializer = new DataContractJsonSerializer(thing.GetType()); var ms = new MemoryStream(); serializer.WriteObject(ms, thing); var json = Encoding.Default.GetString(ms.ToArray());    However, I get the following exception when this is executed:     Type   '<>f__AnonymousType1`3[System.Int32,System.Int32,System.Object[]]'   cannot be serialized. Consider marking   it with the DataContractAttribute   attribute, and marking all of its   members you want serialized with the   DataMemberAttribute attribute.  See   the Microsoft .NET Framework   documentation for other supported   types.   I can't apply attributes to an anonymous type (as far as I know).  Is there another way to do this serialization or am I missing something?


I'm using an OVH web server, I went to the ftp browser and did add all my files into www.  I was using Drupal 8 in local.   When I want to go to my website, I've this error:     The provided host name is not valid for this server.

I got the trusted host settings error.      The trusted_host_patterns setting is not configured in settings.php. This can lead to security vulnerabilities. It is highly recommended that you configure this. See Protecting against HTTP HOST Header attacks for more information.    I read the  but I'm not understanding some of the basic context.   Are the "trusted hosts" me and other administrators who want to be able to administer the site remotely?  If so, would I add my PC's domain to the trusted host list?


I have problems understanding this two sentences:   There are no entailment relations for any of an omnipotent, omniscient being‘s allowances of evils E1…En between his allowances of those evils and greater (possible) goods. There are not entailment relations for all of an omnipotent, omniscient being‘s allowances of evils E1…En between his allowances of those evils and greater (possible) goods.

I started to learn English recently and I have one misunderstanding about the usage of "all" and "any". In what cases should we use "all" and in what "any"? Why does the following example:     There was something false in all this.   use "all" instead of "any"?


Can you quit during the Play of the Game and still get it? Or when the cards are shown, but before the XP screen? Or do you have to wait past everything?

Let's say my career best in eliminations is 20. Then I play a game from the start and I do 21 eliminations, but I disconnect before VICTORY/DEFEAT appears. Will my career best now be 20 or 21? Will my averages change? What about if I disconnect after VICTORY/DEFEAT, but before the stats appear?  At what point exactly do my stats get modified?


If a man holds and hangs from the power cable of trains with one hand, will he be alive or will he die if he holds and hangs from the electric wire using two hands without touching the ground ? I think in the first case he will survive as electric current does not pass through him if he holds it with one hand. But in the second case current passes through him if he holds it with two hands and he may not survive. But is the second case right ?

We have seen birds sitting on uninsulated electric wires of high voltage transmission lines overhead without getting harmed, because sitting on only one wire doesn't complete any circuit.   But what about the potential difference between their legs? Is this not a small complete circuit? Because the wire has a potential gradient, there should be a potential difference between the bird's feet. Is this potential difference so very small that we can say the bird is sitting at a single point on the wire? If a bird of a sufficiently large size, with a wide gap between its feet, sits on a single wire, shouldn't the bird receive a shock if the potential difference is sufficient?


Is there a way to do this. I often find myself browsing files in the GUI because it is convenient and then I need a terminal so I have to open one up and cd /dsf/sd/f/sd/f/sd/fsdf with autocomplete it is quicker than typing, but it would be nice to have a shortcut to just open a terminal with one click

I am new to Ubuntu, and was wondering whether it is posible to open a terminal with a path matching your current location in the file manager? In Windows it was very easy, but how do you do it in Linux?


I have a very simple code with a clear task - to make 10 cars race asynchronous.  this is the code:   class Program {     static void Main(string[] args)     {         int numOfCars = 0;         const int destKm = 1000;         Random rng = new Random();         Console.WriteLine("Write the number of cars in the race");          while (!(int.TryParse(Console.ReadLine(), out numOfCars)))         {             Console.WriteLine("You must enter a valid int. Please try again");         }          Car[] cars = new Car[numOfCars];         int randomNumber;         for (int i = 0; i < numOfCars; i++)         {             randomNumber = rng.Next();             cars[i] = new Car(i, new SynchronizedRandomGenerator(0, 100), destKm);          }          Thread[] raceThread = new Thread[numOfCars];         for (int i = 0; i < numOfCars; i++)         {             raceThread[i] = new Thread(() => cars[i].Race());             raceThread[i].Start();         }           Console.ReadLine();     } }     public sealed class Car {     public SynchronizedRandomGenerator RandomGenerator { get; private set; }      public int CarId { get; private set; }      public int DestKm { get; set; }      public Car(int carId, SynchronizedRandomGenerator randomGenerator, int destKm)     {         DestKm = destKm;          CarId = carId;          RandomGenerator = randomGenerator;     }      public void Race()     {         int kmSoFar = 0;         while (kmSoFar < DestKm)         {             kmSoFar += RandomGenerator.Next();             Thread.Sleep(10);         }         Console.WriteLine($"Car {CarId} Has Finished The Race");      } }      public sealed class SynchronizedRandomGenerator {     public  int MinValue { get; private set; }      public int MaxValue { get; private set; }      Random rng = new Random();      public SynchronizedRandomGenerator(int minValue, int maxValue)     {         rng = new Random();          MinValue = minValue;          MaxValue = maxValue;     }      public int Next()     {         return rng.Next(MinValue, MaxValue);     } }   I recive exception at the line raceThread[i] = new Thread(() => cars[i].Race());   for some reason, it raise the value of "i" after it entered the loop and causing the exception. However when I'm debug and run it line by line it seems to work.

I met an interesting issue about C#. I have code like below.  List<Func<int>> actions = new List<Func<int>>();  int variable = 0; while (variable < 5) {     actions.Add(() => variable * 2);     ++ variable; }  foreach (var act in actions) {     Console.WriteLine(act.Invoke()); }   I expect it to output 0, 2, 4, 6, 8. However, it actually outputs five 10s.  It seems that it is due to all actions referring to one captured variable. As a result, when they get invoked, they all have same output.  Is there a way to work round this limit to have each action instance have its own captured variable?


Did a clean install 16.04.3lts on a Lenovo T60. After updating and restart. It goes to blank screen.    Not sure what to do next

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 am looking at my favorited posts and I am wondering what "kviews" means?

What is the meaning of the kviews unit used on Stack Overflow??


The code below is for a function that can only be invoked 3 times, the code is correct. What I don't understand quite well is this part:   var combi = returnIt() + returnIt() + returnIt();   I understand whats happening insight the threet function (and that func is being called up to counter==3) but how does it gets REMEMBERED outside of it? Not sure if I explained clear enough what I mean..  var returnIt = threet(function() {   return 5; });  function threet(func){   var counter = 0;   return function(){     if(counter < 3){         counter++;         return func();          }    } } var combi = returnIt() + returnIt() + returnIt(); combi;

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


I consider myself javascript beginner and had a question regarding measuring the performance of JavaScript code. Say I have the below code - functionA() {   start = performance.now();         // Execute some code.....   functionB();   functionC();   end = performance.now();   console.log(`Time taken: ${end - start}`); }  Will the calculated time take into account the execution time of both the sub functions? I thought JavaScript is single threaded and hence, it should be the case. Then I read somewhere that JavaScript Runtime is actually multi threaded, which makes sense because if one part of your code is taking long to execute, it can run other parts of your code in another thread. If this is indeed true and the above code would not be optimal, is there a way to measure performance which takes into account all the sub functions?

I need to get execution time in milliseconds.  I originally asked this question back in 2008. The accepted answer then was to use  However, we can all agree now  that using the standard  API is more appropriate. I am therefore changing the accepted answer to this one.


I was thinking about social chameleon but it may be a more accurate word(or word combination) for that.

What term would communicate something similar to "brown noser", without the vulgar connotation?  (Here's one citation of the term being , but I'm guessing it was used before that.  In any case, the term is used by people in American culture today. From the link to WWII Vocabulary: "Brown-noser: Ass-kisser. To curry favor, or “boot-lick.” Variation: Brownie"  What term/phrase communicates 'speaking or acting to please those with authority or position to gain favor', without the crude connotation of the term 'brown-noser'?  Example sentence:       "Did you hear what Bob said about the company track record in our employee meeting yesterday?  He's a ______"


If$$A=  \begin{bmatrix}     1 & 4   \\     2 & 3   \end{bmatrix},$$then find $A^5-4A^4+7A^3+11A^2-A-10I$ where $I$ is Identity matrix of $2^{nd}$ order.    Answer should come in terms of $A$ and $I$.   My approach: I thought it would might end up in a pattern so I found   $$A^2=\begin{bmatrix}    9 & 16   \\    8 & 17  \end{bmatrix}$$ and similarly $A^3$ but got no such pattern. I don't want to evaluate it to up to $A^5$. Any better approach or solution is much appreciated.

Question: Use Cayley-Hamilton theorem to express $A^5-4A^4-7A^3+11A^2-A-10I$, where $$A= \begin{pmatrix}1&4\\2&3\end{pmatrix}$$  Attempt: I only know how to get the characteristic polynomial equation which is $\lambda^2-4\lambda -5$ for that matrix. By definition $A^2-4A-5=0$. But where does that  5 degree polynomial come from?


I really need help understanding this sentence right here:   "Every vector space is regarded as a vector space over a given field, which is denoted by F."  I know from my professor and the book that: 1) Vector space= a set of vectors in which 2 operations are defined ( addition and scalar multiplication) so that when you add any 2 vectors in the vector space, that unique element would also be in the vector space, and the same holds for scalar multiplication.  2)Field=the set of all real numbers or complex numbers.  My question is: what does it mean to have a vector space over a field?   Thanks you so much.

I am getting a bit confused with the terminology here. I understand that a field means some set of scalars like real numbers but why do we need a field for a vector space? Are not the numerical values used to define a vector are inherent properties of the vector space? Why do we term it like "vector space over real field"? If not numbers, what are the other fields possible for a vector space because you obviously numbers to define the value of magnitude and direction of the vectors?


I am traveling from New Delhi IGI Airport to Blagnac Airport Toulouse via Heathrow London, I would be boarding my flight at 10.20 am from India which will drop me at Toulouse at 20.35 with a 5-hour layover at Heathrow. I am going on a student visa, do i require an airport transit visa. If so please assist me how to apply for transit visa.

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


I tried the following html:

   What I was trying to accomplish was that the second link element, which contains an image, to be in the top right of the first image. However, the smaller image stays on the outside of the other one. Is there any possible way this could be done with the same layout? If not, then please tell me how I could make it work.

I want to overlay one image with another using CSS. An example of this is the first image (the background if you like) will be a thumbnail link of a product, with the link opening a lightbox / popup showing a larger version of the image.   On top of this linked image I would like an image of a magnifying glass, to show people that the image can be clicked to enlarge it (apparently this isn't obvious without the magnifying glass).


I am trying to have some meaning from my apache log files: I want to parse my access log and have some statistics about 200 status code hits (how many times each of them was hit).  So I tried to learn some awk magic and here what I got right now:  grep "HTTP/1.1\" 200" access.log | awk '{print $7 } ' | sort | uniq -c | sort -n   This is doing most of the things I want: it selects all logs entries that ended up with 200 hit from access.log then selecting a part which corresponds to path that hit generated, sort them, count each unique element and sort based on the number of times this unique element was hit.  So result looks like this:    1 /public/img/upload/image_3.jpg   2 /public/img/upload/image_2.jpg   8 /public/img/upload/image_1.jpg  18 /public/js/main.js  33 / 236 /index.html   I am trying to push it a little bit further:   because I have logrotate, I have many other files like access.log.1, ..., access.log.N and I want to get this statistics for all of them together. The only solution I have found is to use grep "my 200 expression" -R /pathToDirWithLogs which will grep over all files in directory, which clearly is not nice, because it will grep not only logs. Listing the files is also not an option, because I do not know the number N. I do not really care about each individual file in /public/img/upload/, I just care how many of them was hit. Here I am totally lost, having no idea how to start. But here is an example what I want for my simple output   11 /public/img/upload/*  18 /public/js/main.js  33 / 236 /index.html   Here public/img/upload represents all hits which were generated there: 8 from image_1, + 2 from image_2 and 1 from image_3.  Are there any awk, grep magicians to show me the way?

I can use log analyzers, but often I need to parse recent web logs to see what's happening at the moment.   I sometimes do things like to figure out top 10 ips that request a certain file  cat foo.log | grep request_to_file_foo | awk '{print $1}' |  sort -n | uniq -c | sort -rn | head   What do you have in your toolbox?


For which positive numbers $b$ is it true that $$b^x \geq 1+x,\forall x ?$$  My calculus teacher gave this question on a test recently, and I’m not sure how to solve it. Any help is appreciated.

Calculus book:     Find all numbers $a$ such that $\forall x, a^x \ge 1+x$    I immediately thought of the inequality $e^x\ge 1+x$ and guessed that the answer was any number $a$ in $[e,\infty)$. After playing around with a graphing app I can see this is definitely true, although I can't explain why.   Why is $e$ specifically the smallest number such that the inequality holds? To my untrained eye, a quick scan of the equation does not give rise to anything involving the constant $e$. Maybe because $1+x$ is only a tangent to the equation $a^x$ when $a=e$? Thanks.


When I open the terminal-app, there is this default code. However, it changes depending on the network: This is how it looks like in my local coworking office: Last login: Thu Aug 13 14:49:57 on ttys000 HUAWEI_P20-12345678:~ user$   This is how it looks like at home or with wlan disconnected: Last login: Thu Aug 13 14:51:36 on ttys000 MyMac:~ user$   I don't know what a HUAWEI P20 should be? I have an iPhone and I can't believe that the coworking office has a cellphone as router? Did my computer get hacked? What does this line mean and what difference does it make? Furthermore, what does ttys000 mean? btw, MyMac is obviously the name of my computer and I replaced my username with "user".

My computer name in System Preferences > Sharing is set to "archos", but is showing as "iphone" on Terminal. It just started doing this after I loaded Xcode for doing iPhone development: Last login: Mon Nov  7 14:46:55 on ttys001 iphone:~ travis$   Any ideas what could be causing this?


Let $$I=\int\frac{dx}{\sqrt{ax^2+bx+c}}$$ I know this can be either $$\displaystyle I=\frac{1}{\sqrt{a}}\ln\left({2\sqrt{a}\sqrt{ax^2+bx+c}+2ax+b}\right)+C$$ $$\displaystyle I=-\frac{1}{\sqrt{-a}}\arcsin{\left(\frac{2ax+b}{\sqrt{b^2-4ac}}\right)}+C$$ Or $$I=\frac1{\sqrt{a}}\mathrm{arcsinh}\left(\frac{2ax+b}{\sqrt{4ac-b^2}}\right)+C$$ Can you tell me the difference between these three solutions? Thanks a lot

Is there a way to solve this integral?  $$\int \frac{dx}{\sqrt{-ax^2 + bx +c}}, \;\;\;\;\; \forall\; a,b,c \in (0,+\infty) \;in\;R$$  I have tried it by changing of variable and by parts, but no result. I don't know what else to do.  Thanks in advance.


In the Guardians of the Galaxy Movie, we see Peter Quill (aka Star-Lord) and meet his mother at the start of the movie.  We also find out at the end that:      Yondu was meant to deliver Peter to his father.   But who was that?

At the end of the new Guardians of the Galaxy Vol. 2 Trailer we meet Star Lord's father:                                  Dad appears to be human. But Peter Quill's mother said in the first film that his father was a      "being made of pure light".    What race (species?) is Star Lord's father in the MCU?


Which of these sentences are correct?  1. The songs or the title of the playlist was updated. 2. The songs or the title of the playlist were updated. 3. the title or the songs of the playlist was updated. 4. The title or the songs of the playlist were updated.

Should I use 'was' or 'were' in this example?     I was always delighted when my brother or one of my sisters was/were asked to do them.


I have two machines 1 iMac 2009 24” and one MacBook Pro 2017 touchbar. The iMac I cannot open at all as I erased everything from the Macintosh HD. I am trying to fix by using Catalina on the MacBook Pro to create a bootable USB to boot the iMac from.   The 2009 iMac had two partitions in its Harddrive, one for HD Mactintosh and one for BootCamp. I wanted to wipe everything so I shutdown the machine then started it while hitting CMD + R then I get the restore window and I choose restore Mac OS then it asks me to sign it to my apple store and I enter my App Store details but it gives this error This item is temporarily unavailable I wonder how I can get the macOS restored if anyone could please help as I am kinda stuck and don't know how to solve this.  I have downloaded the El Capitan .dmg file and erased a 32GB USB stick to macOS journaled but I don’t know how I can make it bootable from the dmg file? And then how I can use the bootable USB to install the macOS?

Sometimes it's hard to search for older versions of macOS & OS X  on the App Store.  This is an attempt to provide the canonical QA for this issue, as per the Meta QA -  I expect it to be modified over time to hopefully become a complete information resource.  How can I get any older version of a Mac OS to be able to run as a VM, or to reinstall on my Mac?


When I go into my Apple Software Updates on my OS X 10.6.8 computer to update to OS X 10.9, the computer tells me that I do not have any new updates.  How can I upgrade to OS X 10.9 if it does not give me that option?   Operating system of my iMac   Model Name:   iMac   Model Identifier: iMac10,1   Processor Name:   Intel Core 2 Duo   Processor Speed:  3.06 GHz   Number Of Processors: 1   Total Number Of Cores:    2   L2 Cache: 3 MB   Memory:   4 GB   Bus Speed:    1.07 GHz


I am a beginner trying to learn Illustrator and this is really driving me crazy.   I have a picture of a caricature of my grandmother.  I want to make it editable and change the colors so I can put it on a t-shirt.  I have already cleaned up the image in Photoshop and filled the lines onto an empty layer. I placed the PSD into Illustrator, live traced the image, expanded it, and ungrouped it.   Everything goes fine until I try to change the stroke color. No matter what I do, it will only change to shades of gray.  I think what I want to do is called "converting hand-drawn sketch to vector" but I'm not sure.

When I try to change the color after tracing a JPEG image in Illustrator and expanding it, it becomes gray. I have tried lots of color changes but the result is always the same.   Why can't I change the color to anything other than gray, on an image I've traced in Adobe Illustrator?  How can I change the traced image's color?


The question is as the title states, with the additional information that $a\in A$ where $A$ is a field, and $a$ is non-zero.  I don't get very far, simply that $a^{-1} = a \iff a\cdot a = 1$. But from here I don't know what to do.

Let $F$ be a field.   And let $a \in F$ such that $a \cdot a = 1$.  Claim: $a = 1$ or $ a = -1$  Before, I begin with the proof I cannot understand what $ a = -1$ represents...  Is $a = -1$ representing the inverse of $a$?   I am capable of getting to $a = 1$ with no trouble, but how do you get the $-$ sign to show up in your proof?   Proof: This is my attempt at getting to $a=-1$.  If $a = 0$ then we have $0 \cdot 0 = 0 \neq 1$. Then this implies that $a \neq 0$ which implies that $ \exists b \in F,$ s.t. $a \cdot b = 1$, i.e. $b$ is the multiplicative inverse of $a$.  Knowing this fact prove as follows...:  $a \cdot a = 1 \implies$ $ (a \cdot a) \cdot b = 1 \cdot b \implies$ $a \cdot (a \cdot b) = 1 \cdot b \implies$ $a \cdot 1 = 1 \cdot b \implies$ $ 1 \cdot a =1 \cdot b \implies$ $a = b$.   But since $b$ is the multiplicative inverse of $a$ is this enough to say that $a = -1$?


I want to recursively change many files named raw.tex to parent-directory-hw.tex. Is there a simple scripting solution to this problem?  For example, running the script on  . `-- root     |-- baz     |   `-- raw.tex     |-- foo     |   `-- bar     |       `-- raw.tex     `-- spam         |-- eggs         |   `-- raw.tex         `-- raw.tex   should result in  . `-- root     |-- baz     |   `-- baz-hw.tex     |-- foo     |   `-- bar     |       `-- bar-hw.tex     `-- spam         |-- eggs         |   `-- eggs-hw.tex         `-- spam-hw.tex

I am trying to rename a bunch of files according to the names of their directory in Linux, SSH.  I have a directory called XYZ01smith. In it are four files called smith_5*.I need to add prefix XYZ01 to these files. But, the next directory is called XYZ02perry. In it are four files called perry_3*. I need to add the prefix XYZ02 to these files.  I have a loop to do this per directory:  for i in smith_5*;     do mv ${i} XYZ01${i}; done    But I have 50 directories (XYZ01name to XYZ50name), so I would rather be able to do this with one script for all 50. I am sure this should be possible, but I do not know how.


Hi I recently added a 404 page to a website found here:  The id "greywrap" already existed and CSS detects styles fine, but then I added "404" "404title" and "404subtitle" classes and added to the stylesheet but they are not applying. This could be just a simple stupid mistake, but having a hard time finding it. Thanks in advance for any help!  HTML

404 Error

Sorry. We can't seem to find the page you're looking for.

   CSS  .404 {     padding: 70px 0 60px; }  .404title {     margin-top: 100px;     font-size: 72px;     line-height: 1.2;     text-transform: uppercase; }  .404subtitle {     font-size: 38px;      text-transform: uppercase; }

What characters/symbols are allowed within the CSS class selectors? I know that the following characters are invalid, but what characters are valid?  ~ ! @ $ % ^ & * ( ) + = , . / ' ; : " ? > < [ ] \ { } | ` #


My SONY VAIO Laptop with a fresh UBUNTU 18.04 install cant seem to find the Wi-fi Adapter, found this info on the Adapter:  *-network        descripción: Ethernet interface        producto: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller        fabricante: Realtek Semiconductor Co., Ltd.        id físico: 0        información del bus: pci@0000:0e:00.0        nombre lógico: enp14s0        versión: 0c        serie: 3c:07:71:53:c2:03        tamaño: 100Mbit/s        capacidad: 1Gbit/s        anchura: 64 bits        reloj: 33MHz        capacidades: bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation        configuración: autonegotiation=on broadcast=yes driver=r8169 duplex=full firmware=rtl8168g-2_0.0.1 02/06/13 ip=192.168.0.167 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s        recursos: irq:18 ioport:2000(size=256) memoria:c0500000-c0500fff memoria:c0400000-c0403fff AVISO: la salida puede ser incompleta o imprecisa, debería ejecutar este programa como superusuario.

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


Is there a standard formula/convention to calculate the % of ownership on a property based on the following situation   I am buying property together with my partner and her mother. Lets assume for now the property was priced at $100,000 for easy calculation My partner and mother are putting a downpayment of $30k each ($60k) from their own personal funds  I am putting $0 in downpayment We are taking out a mortgage on the remainder $40k. My wife, her mother and myself plan to split the monthly mortgage payment evenly (3 ways).   My assumption is that the property ownership should be calculated based on - Partner and mother own 30% each from their initial $30k downpayment - Remainder % is calculated based on amount each of us are paying to the monthly mortgage  Would the above be right or is there a more conventional to calculate this?

Let us assume a shared ownership house, where everything is 50/50 in terms of deposit, monthly payments, bills, and eventually estate agent costs, and lawyer costs when the house is sold.  If the mortgage is over 25 years and for the first 5 years both owners live in the house and split everything 50/50, how do the calculations and ownership percentages change if one of the owners decides to move on and rent elsewhere, leaving the other owner to pay 100% of the mortgage bills etc etc?  After the 25 years, do both owners still get 50/50 when the house is sold?


I have text file look like this:    If you are a software developer in your 20s or 30s, you've grown up in a world dominated by Linux. It has been a significant player in the data center for decades, and while it's hard to find definitive operating system market share reports, Linux's share of data center operating systems could be as high as 70%, with Windows variants carrying nearly all the remaining percentage. Developers using any major public cloud can expect the target system will run Linux. Evidence that Linux is everywhere has grown in recent years when you add in Android and Linux-based embedded systems in smartphones, TVs, automobiles, and many other devices.   i want to shrink it so it look like this   If you are a software developer in your 20s or 30s,  you've grown up in a world dominated by Linux. It ha s been a significant player in the data center for d ecades, and while it's hard to find definitive opera ting system market share reports, Linux's share of d ata center operating systems could be as high as 70% , with Windows variants carrying nearly all the rema ining percentage. Developers using any major public  cloud can expect the target system will run Linux. E vidence that Linux is everywhere has grown in recent  years when you add in Android and Linux-based embed ded systems in smartphones, TVs, automobiles, and ma ny other devices.   and then enlarge it so it look like this:  If you are a software developer in your 20s or 30s, you've grown up in a world dominated by Linux. It has been a significant player in the data center for decades, and while it's hard to find definiti ve operating system market share reports, Linux's share of data center operating systems could be as high as 70%, with Windows variants carrying nearly all the remaining percentage. Developers using a ny major public cloud can expect the target system will run Linux. Evidence that Linux is everywhere has grown in recent years when you add in Android and Linux-based embedded systems in smartphones,  TVs, automobiles, and many other devices.   how can I do that, i need to include that in my script

I know that I can use something like cat test.txt | pr -w 80 to wrap lines to 80 characters  wide, but that puts a lot of space on the top and bottom of the printed lines and it does not work right on some systems  What's the best way to force a text file with long lines to be wrapped at a certain width?   Bonus points if you can keep it from breaking words.


I have an array with objects inside of it.  var obj1 = [  user1 = {   "name" : "John",   "age" : 24,   "city" : "London"  },  user2 = {   "name" : "Jane",   "age" : 22,   "city" : "New York",  } ];   Now what I would like to do is to get name of the objects inside the array so in this case it would be "user1" and "user2".  FIRST TRY  At first I tried doing it like this:  for(i = 0; i < obj1.length; i++){  document.getElementById('app').innerHTML += obj1[i]; }   And the outcome is [object Object][object Object]  SECOND TRY   So then I tried to use JSON.strigify on the objects, but then it returns the whole object and not it's name as I would like to:  for(i = 0; i < obj1.length; i++){  document.getElementById('app').innerHTML += JSON.stringify(obj1[i]); }   Outcome:  {"name":"John","age":24,"city":"London"}{"name":"Jane","age":22,"city":"New York"}   QUESTION  Is it possible, and if yes how should I go about displaying names of all of the objects inside of an array, but not displaying their content. Desired outcome:  user1 user2

Say I create an object thus:  var myObject =         {"ircEvent": "PRIVMSG", "method": "newURI", "regex": "^http://.*"};   What is the best way to retrieve a list of the property names? i.e. I would like to end up with some variable 'keys' such that:  keys == ["ircEvent", "method", "regex"]


Prove that the nilradical of $\mathbb{Z}_m$  is the set $\{0\}$ if and only if $m$ is not divided by any square of a prime number.   Here is my attemt for one part of the problem:  Let $N(\mathbb{Z}_m)=\{0\}$ and suppose that there exists a prime $p$ such that $p^2|m$.  Then $m=sp^2$. I took the element $[ps]\in \mathbb{Z}_m$ for which we have that $[ps] \neq [0]$ and $ps<m$.  We see that $[ps]^2=0$ thus $N(\mathbb{Z}_m) \neq \{0\}$ deriving a contradiction.  Is this part of the proof correct?  Can someone help me to prove the other part  of the statement?  Thank you in advance!

Let $n>1$ be an integer. Prove that $0$ is a radical ideal in $\mathbb{Z}/n\mathbb{Z}$ if and only if $n$ is a product of distinct primes to the ﬁrst power (i.e., $n$ is square free). Deduce that $(n)$ is a radical of $\mathbb{Z}$ if and only if $n$ is a product of distinct primes in $\mathbb{Z}$.  I don't really get it. For example, $8$ is not a square-free integer; so take $\mathbb{Z}/8\mathbb{Z}$. Why is $0$ not a radical ideal in this ring but is in $\mathbb{Z}/6\mathbb{Z}$?


I use PDF figures that are output by Excel with excessive whitespace. There are only a few standard sizes, so I would like to define re-usable variable to set in the [trim = ???] option for the \includegraphics[]{} command.  I have tried putting this at the beginning:  \newcommand{\exsff}{trim = {1in 3.5in 1in 3.5in}}   and this when I insert the graphic:  \includegraphics[width=1\linewidth, \exsff]{figure_name}   but I get an error. If I hardcode it in like this, it works:  \includegraphics[width=1\linewidth, trim = {1in 3.5in 1in 3.5in}]{figure_name}   Any suggestions?

\documentclass[a4paper,10pt,twoside]{book} \usepackage[demo]{graphicx}  \begin{document}  \newcommand{\scalefactor}{scale = 0.25}  \begin{figure}[!ht]   \centering   %Next line does not work   \includegraphics[\scalefactor]{image}   % The following line works   %\includegraphics[scale = 0.25]{image} \end{figure}  \end{document}   Output:  ! Package keyval Error: scale = 0.25 undefined.   I need to scale a number of images by the same factor, hence the command.   How to solve this and more importantly Why is this only specific to \includegraphics


I'm trying to calculate the acceleration an accelerometer would read NOT placed in the Center of Gravity of the object. Let's look at the figure below (or in link provided). The accelerometer was placed in location $(Xa,Za)$ and not in the CG of the object. Given that the accel's output is a_x and a_z at this location (Xa,Za). What would've the accelerometers have read if placed on the C.G. of object?  [IMG]  Here is an attempt at the solution () however I don't fully understand how they got the transformation matrix.   How does q_dot come into play in the calculations and how does alpha (angle) disappear in the matrix?

I am in search of a simplified version of the derivation of  (both translational and rotational) for a rigid body (3D block) that has a body fixed frame and where the center of mass of the body is not at the center of gravity.  I can find elementary derivations for the same system when the center of mass is at the center of gravity, but not for my system in question.    I am using the derivation as background research for a rotordynamics project that I'm working on.  Any help and or references would be greatly appreciated!  :)


Where do I place the comma in this sentence?     I am in the process of renewing my insurance policy however I don't know the correct amount.

Is this a comma splice?   What makes a sentence a comma splice?     Being left at the altar on her wedding   day, Pamela became furious.


locked by Shog9♦ Jul 19 at 22:30 This question's answer is a collaborative effort: if you see something that can be improved, just edit to improve it! No additional answers can be added here  I'm sure the answers to this question are useful, but why is this particular one allowed when we generally disallow resource recommendation questions? Even though you can't add new answers, the existing answers can still be edited and people are making edits quite frequently.

is locked  with the following notice:     This question and answer are a collaborative effort: if you see something that can be improved, edit it!    Except that while the answer can be edited because it's a Community Wiki question, the question itself  can't be, because it's locked. I don't know the reason why it was locked, but maybe the notice's text should be changed or omitted? (I have no opinion on whether the question should stay locked or not.)


I am writing python code that involves a series of math calculations. One such is the following operation:  result1 = float1 % float2 //modulo operation to find the remainder  where float1 = 6816605016955680000000 and float2 = 1577917828000 The result I get is 1573597498272 (reverse math shows that this is not accurate). I get the same result on Excel or Numbers as well. However, when I try this on a quad-core system, Excel and Numbers give a very different result which is 1573597828000 (reverse math shows this is accurate). The python program continues to give the same old result even on the quad-core system. (Python version is 3.7.2 on my system and 3.9 on quad-core system). What can I do to ensure python gives me the accurate result? Any guidance would be super valuable. Thanks in advance.

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


We know that every planet in our solar system revolve's around the sun in a particular orbit. But were to they get the energy to revolve around the sun. And why do they not drop into the sun there is only gravitational force acting which is always attractive in nature?

Why doesn't the Moon fall onto the Earth? For that matter, why doesn't anything rotating a larger body ever fall onto the larger body?


I have  $$ \lim_{(x, y) \to (0, 0)} \frac{y^2 \sin^2 x}{x^4 + y^4} $$  I've tried setting $y= 0, x=0, y=mx, y=x$, and lots of other things but because of the $\sin$ I keep getting a limit of zero. How do you show this doesn't exist?

$$ \lim_{(x,y)\to(0,0)}\frac{y^2\sin^2x}{x^4+y^4} $$  I believe the limit doesn't exist but I'm not sure how to prove/evaluate correctly. A hint would be great. Thanks.


I have a specific query that executes a stored procedure on a remote linked server and inserts the results into a local temp table.  I don't want it to promote a remote procedure transaction but I can't re-configure the server.  Is there a query hint or some way to force it to not promote a remote procedure transactions?  Edit: The reason I ask is because I'm getting the following error when trying to execute my remote procedure call:     OLE DB provider "SQLNCLI11" for linked server "MyRemotelyLinkedServer" returned   message "The transaction manager has disabled its support for   remote/network transactions.". Msg 7391, Level 16, State 2, Procedure   spMyRemoteProcedure, Line 64 [Batch   Start Line 15] The operation could not be performed because OLE DB   provider "SQLNCLI11" for linked server "MyRemotelyLinkedServer" was unable to   begin a distributed transaction.   I know I can set "Enable Promotion of Distributed Transactions" to false on the Linked Server options to fix this, but I'm not allowed to make server option changes in this context, so I'm looking for a workaround.

I am using SQL Server 2014. I want to execute EXEC (@remotecmd) AT [server_name]; (@remotecmd is a dynamic sql not a stored procedure) into ##eapb. My code is  insert into ##eapb EXEC (@remotecmd) AT [ADSQLDB3S\DEV];   But I get the error:     OLE DB provider "SQLNCLI11" for linked server "server_name" returned message "The transaction manager has disabled its support for remote/network transactions.".       Msg 7391, Level 16, State 2, Line 71       The operation could not be performed because OLE DB provider "SQLNCLI11" for linked server "server_name" was unable to begin a distributed transaction.   If I remove the insert into ##eapb, I have no error.  The Linked Server has the RPC Out option set to True.


How do I show through mathematical induction that   \begin{equation} \frac{d^n}{dx^n}[f(x)\cdot g(x)] = \sum_{k = 0}^{n} \binom{n}{k} \frac{d^k}{dx^k} [f(x)] \cdot \frac{d^{n-k}}{dx^{n-k}} [g(x)] \end{equation}  which is the product rule for higher derivatives?

Assume $f$ and $g$ are differentiable at $x$. Prove that $(fg)^{(n)} = \sum_{k=0}^n \binom{n}{k}f^{(k)}(x)g^{(n-k)}(x)$   I am assuming here $fg = f(x) g(x)$. Then we can prove this via induction. If $n = 0$ we have $1 = 1$ which is true. Now assume it is true for some $m$ we need to show it is possible for $m+1$. We have $(fg)^m = \sum_{k=0}^m f^{(k)}(x)g^{m-k}(x)$. How do we show that?


yesterday I did a fresh install with ubuntu 17.10.   Then I did some playing around with themes and extensions. Then I did a reboot and after the reboot the gnome-bar became very ugly.   It should look like this:   (light transparency of the bar, calendar in center)  But instead it looks like this:     (No transparency, calendar at the right side, theme doesn't seem to apply)  How do I get back the nice gnome panel from the first screenshot?     additional notes:   After the reboot, that broke the bar, also a lot of extensions appeared. I couldn't remove them via extensions.gnome.org/local/, so I removed them via rm -r. For some reason those unwanted extensions come back, when I do sudo apt-get install --reinstall gnome-shell-extensions. I'd like to get rid of them permanently, but for now I'm fine.

This is how my desktop looks after the update, the top bar turning grey and the addition of the bottom bar happened after the update.    From my searching of screenshots this does not appear to be how it is supposed to be. Is there any way to fix it?


I am making an api in which i fetch data which contains column some special character value when i convert them in json format it's value is change from 100Ã¢ÂÂ¬ to 100Ã¢Â\u0082Â¬ . I don't want this \u0082 extra characters .  Here is my code  $UserDetailSql    = "SELECT * FROM `characteristic` WHERE event_id='" . $events->id . "'";   //$this->_db->my_query("SET NAMES 'UTF8'");  $UserDetailSqlVal = $this->_db->my_query($UserDetailSql);  $temp_char = array();  while($characteristic = $this->_db->my_fetch_object($UserDetailSqlVal)){      $char_temp['characteristic_id'] = $characteristic->characteristic_id;       $char_temp['title_description'] = $characteristic->title;      $char = $this->_common->getEventCharacterstics($characteristic->characteristic_id);      $char_temp['title'] = $char->title;       $char_temp['image'] = IMG_PATH.'characterstics/'.$char->image;       $temp_char[] = $char_temp; } $temp['characteristic'] = $temp_char; echo json_encode($temp);`      Here $characteristic->title can have catalan or spanish or english data.The value i give in heading is this column.  I tried utf8_encode(),htmlentities(),htmlspecialcharacters() but no luck please help i am fed up now.Thanks in advance.

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


Show that $I=(X_{k_1}^{a_1},...,X_{k_s}^{a_s})$ is $(X_{k_1},...,X_{k_s})$-primary.   I noticed  that $$\sqrt{({X_{i_1}}^{a_1},...,{X_{i_k}}^{a_k})}=\sqrt{({X_{i_1}}^{a_1})+\cdots+({X_{i_k}}^{a_k})}=\sqrt{\sqrt{(X_{i_1})^{a_1}}+\cdots+\sqrt{(X_{i_k})^{a_k}}}=\sqrt{(X_{i_1})+\cdots+(X_{i_k})}=\sqrt{(X_{i_1},...,X_{i_k})}=(X_{i_1},...,X_{i_k}).$$ I have to show that $I$ is $P$-primary (where $P=(X_{k_1},...,X_{k_s})$), i.e., if $u v\in I$ then $u\in I$ or $v\in P$. I tried to prove that if $u\notin I$ and $v\notin P$ then $uv\notin I$. (There is a similar question, but the answer is too hard for me.)


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.


I need the format of the section titles to match with the default ones used in MS Word (actually with a bit different coloring), but I can't really find a way to change specificly the sections' format. What is the way of doing this?  (my LaTeX docs should look like some previously written Word docs)  What I have:    \documentclass[12pt,a4paper]{book} \usepackage{enumerate}           \usepackage[utf8]{inputenc}       \usepackage[T1]{fontenc} \usepackage{lmodern} \usepackage{amssymb}         \usepackage{amsmath} \usepackage[ a4paper, top=1in, bottom=1in, left=1.25in, right=1.25in]{geometry}  \usepackage{fancyhdr}    \usepackage{color} \usepackage[hungarian]{babel} \usepackage{graphicx} \usepackage{titlesec} \usepackage{xcolor} \usepackage{sectsty} \usepackage{roboto}  \setcounter{secnumdepth}{3} \setcounter{tocdepth}{4}  \definecolor{darkblue}{RGB}{47,84,150} \definecolor{midblue}{RGB}{0,112,192} \definecolor{lightblue}{RGB}{0,176,240}  \allsectionsfont{\sffamily} \chapterfont{\color{darkblue}} \sectionfont{\color{darkblue}} \subsectionfont{\color{midblue}} \subsubsectionfont{\color{lightblue}}  \begin{document}      \chapter{Chap}     \section{lvl1}     \subsection{lvl2}     \subsubsection{lvl3}  \end{document}   What I want:    edit: I figured out coloring, added pictures and code, I'm using MikTex

I am trying to emulate MS Word 2010 functionality with LaTeX since I am fed up with word.  I am using TexShop, and I have been able to set the main font to Calibri through the use of XeTeX.  How do I set a different font/color/size for every type of section (section,subsection,subsubsection,...), without being limited to the standard LaTeX fonts? It would be nice to be able to choose any font from my system like XeTeX allows me to.  I have tried the package sectsty, but I was not able to figure out how to use Calibri with it.


I found this but i don't undertand it: if [[ "${ARG//[IVXLCDM]/}" != "" ]] then         echo "Wrong input" fi

Thinking about , i decided I can't even create a regular expression that will match roman numerals (let alone a context-free grammar that will generate them)  The problem is matching only valid roman numerals.  Eg, 990 is NOT "XM", it's "CMXC"  My problem in making the regex for this is that in order to allow or not allow certain characters, I need to look back. Let's take thousands and hundreds, for example.  I can allow M{0,2}C?M (to allow for 900, 1000, 1900, 2000, 2900 and 3000). However, If the match is on CM, I can't allow following characters to be C or D (because I'm already at 900).  How can I express this in a regex? If it's simply not expressible in a regex, is it expressible in a context-free grammar?


I have just started with Linux Ubuntu 16.04 (Novice) Looking for PDF Reader for said OS.

Every second e-mail I get suggests to download Adobe Acrobat reader, but .  Which PDF Viewer are there available for Ubuntu? I’m fine with partial solutions, a perfect match however would not only display PDF files, but also be able to:   stageless zoom (not just predefined steps)  open files in tabs display comments added with other PDF software add and save comments display forms filled in with other PDF software fill in and save PDF forms create and save bookmarks have a presentation mode


When I write, I treat references as though they are proper nouns; for example, Chapter 10, Section 10, Line 10, Page 10. (As opposed to chapter 10, section 10, line 10, page 10 - no capital letter.)  [My short forms would be Ch.10, s.10, l.10, p.10]  Until now, I've never been picked up on it. I wrote a piece that involved numerous references to numbered lines. Here is an example from my piece:     Ham makes further attempts to connect with the reader in Line 26, where she writes...   This was corrected to "line 26" (no capital).  I can't really explain why I think references should be capitalised, but I surely must have picked it up from somewhere.  So, my question is - if not common practice, is there anything wrong with capitalising (line) references? Are there any style guides that have a preference for capitalised references?

I found the question  Regarding the number of answers votes and also according to my personal taste I like to capitalize titles. But what exactly are titles? Only the single main book title? What about other smaller semantic parts? Chapter headings, sub-chapter, ...


If we we dig a hole from north pole to the south pole of the Earth and we throw a ball in this hole where would it stop? Will it come back on the surface or it will stop at the centre?

...And you jumped in.  What would happen when you got to the middle of the Earth? Would you gradually slow down, until you got to the middle and once you were in middle would every direction feel like it was up?


I am curious about the following problem:  Can we show that the set $\{p(x)\cdot\exp(-x^2/2)\}\subseteq L^2(\mathbb{R})$, where $p(x)$ is any real-domained polynomial function (i.e., functions in the form of the product between a polynomial function and the exponential function $\exp(-x^2/2)$), is dense in $L^2(\mathbb{R})$?  I am confident in this claim, but fail to prove it. The barrier to me is how to properly use the Stone-Weierstrass theorem (if we need to use it), as it only works on a compact set. Can anyone give me some hint or suggestions? Many thanks!

I know, correct me if I am wrong, that the functions $H_n(x)\exp(-x^2/2)$ form a complete basis in $L^2(\mathbb{R},dx)$, where $H_n(x)$ is the $n$th Hermite polynomial. This must be true also for $x^n\exp(-x^2/2)$ with $n\in\mathbb{N}_0$. Does someone know a proof of the latter or can give me a reference? Since I am not a mathematician, I will really appreciate it if the proof contains all the details that might puzzle a non-mathematician.  I also have the problem to choose functions $f_k$ such that  \begin{equation} \int_{-\infty}^{+\infty}f_k(x)x^n\exp(-x^2)dx = \delta_{kn} \mbox{.} \end{equation}  Does anyone know a method to construct the $f_k$s?


Is it the case that the equation Var(a + bY) = bVar(Y) is always true?  If so, how can you prove that this equation is always true?

Let $A$ and $B$ be two constant matrices and let $x$ and $ y$ be two random vectors, what is the general formula for $Var(Ax+By)$? I know the formula for when $x$ and $y$ are scalar random variables and $A$ and $B$ are constants, but what about the matrix case?


Using blender 2.79 here. One of my file has this issue where faces appear to have an underlying mesh in edit mode, even with a freshly added cube. Any clue?

I have recently started using blender and one of the models I'm working on has dark shadows along edges. I started this model from scratch. I can't remember them being there when I first started the model, but I had trouble joining areas together and think I've pressed something I shouldn't have. However, there are so many options I'm not sure what I did.  Here is an image of what I mean   The one on the left has the shadow. As a test I started a new model, which is on the right in the image, and as you can see it doesn't have any shadows.  Also, occluded vertices partially show through the model. Occlusion doesn't work properly.   In orthogonal view small darkened triangles appear along the the edges.    I don't really want to start the model again from scratch so any ideas on how to remove this shadow would be great. Thanks.


I came upon this simplified example of a memoization function in JavaScript. It's then used to memoize a function that adds 2 to whatever number is passed in. When I saw this, it didn't seem obvious that the memoize function would continue to store the cache variable after being ran since it's not a property of memoize, just (seemingly) an ordinary local variable. Shouldn't it be overridden whenever memoize is called via plusTwo? Where can I find out more about this behavior in JavaScript?  var memoize = function(function_) {     var cache = {};      return function() { // What does this function do?          //makes a string out of the arguments of the function that was passed in         var arg_str = JSON.stringify(arguments);          /*          sets the cache value for the arguments to the value that was already calculated          (if available) or calculates the value for the passed in function on its         */         cache[arg_str] = cache[arg_str] || function_.apply(function_, arguments);          console.log(cache);         // returns the calculated (or cached) value         return cache[arg_str];     }; };  var plusTwo = memoize(function (x) {     return x + 2; });  module.exports = memoize, plusTwo;

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


Even when I am logged in as a non-admin user, when I enter sudo bash or sudo -s, the system does not ask for any password. In the command history, I have not entered any password for sudo earlier (i.e., sudo did not cache any user credentials which might cause it to not ask for my password again in this session.)  Why is this strange behavior? And how do I make sure that every sudo and su command requires a corresponding password? And how to strictly ensure that any user cannot get root privileges without entering the root password?  Here is the content of my /etc/sudoers file:  # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults    env_reset Defaults    secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  # See sudoers(5) for more information on "#include" directives:  #includedir /etc/sudoers.d ALL ALL=(ALL) NOPASSWD:ALL

Whenever I issue command sudo apt-get install foo it does not ask for password. is it because of user groups?  How to make it prompt for password?  Edit: My sudoers file   apple@Ascension:~$ sudo cat /etc/sudoers # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults    env_reset  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  #includedir /etc/sudoers.d ALL ALL=(ALL) NOPASSWD:ALL ALL ALL=(ALL) NOPASSWD:ALL ALL ALL=(ALL) NOPASSWD:ALL


I saw this on the message board and am very interested in this problem.  The question reads as the following.  Let $f$ be continuous on interval $[0,1]$. Prove that $$\lim_{n\rightarrow\infty}\frac{1}{n}\sum_{k=1}^nf(\frac{k}{n})= \int_0^1f(x)dx$$  The person then stated this  Again any help would be greatly appreciate. I have attempted throwing the definition of continuity at it cause it states that it is continuous. I then used a uniform partition  and stated my $M_k$, $m_k$ based on the equation. I had my partition looking like this $P=({0}\frac{1}{n},\frac{2}{n},...,\frac{n}{n})$.  Now I'm having a hard time interpreting the sum on the left. Is this a collection of rational numbers on the interval $[0,1]$? I know that the rationals are dense so there are an infinite amount of points in this interval? Am I reading this correctly?

I am currently studying for a grad test and I have came across one problem that I cannot even begin to solve. I have thrown definitions and theorems at it and just keep running into road blocks. A little help or maybe a shove in the right direction would be appreciated.  The question reads as the following.  Let f be continuous on interval [0,1]. Prove that $\lim_{n\rightarrow\infty}\frac{1}{n}\sum_{k=1}^nf(\frac{k}{n})= \int_0^1f(x)dx$  Again any help would be greatly appreciate. I have attempted throwing the definition of continuity at it cause it states that it is continuous. I then used a uniform partition  and stated my $M_k$, $m_k$ based on the equation. I had my partion looking like this $P=(\frac{1}{n}+\frac{2}{n}+...+\frac{n}{n})$. From here it was not apparent where to go.


My MacBook Pro regularly gets into a state where a very lightly loaded system starts processing very slowly: mouse clicks and button presses take a few minutes to process and a couple of useful things can be done in the space of a couple of hours if I'm attentive.  Note that this happens without fans or any other signal that its running close to its operating limits. Regardless this is undesirable.  MacOS does not seem to recognize this state as a fault or failure, so I need to manually power off, and hence I don't get the "your system was restarted..." message with a crash report on boot (no bugs to be had in MacOS of course). I have XCode installed (linux developer making due on MacOS). How do I force MacOS to dump the state of the running processes and reboot?

I am trying to debug a crashed (or hanging) app. How do I get the diagnostic files from the crash?


I run the command: ll /dev/null and got this output:  crw-rw-rw- 1 root root 1, 3 Feb 19 10:20 /dev/null   I know d means directory. Can someone please explain what the c special flag means?

I've never really got how chmod worked up until today. I followed a tutorial that explained a big deal to me.   For example, I've read that you've got three different permission groups:   owner (u) group (g) everyone (o)   Based on these three groups, I now know that:   If the file is owned by the user, the user permissions determine the access. If the group of the file is the same as the user's group, the group permission determine the access. If the user is not the file owner, and is not in the group, then the other permission is used.   I've also learned that you've got the following permissions:   read (r) write (w) execute (x)   I created a directory to test my newly acquired knowledge:  mkdir test   Then I did some tests:  chmod u+rwx test/ # drwx------ chmod g+rx test/ # drwxr-x--- chmod u-x test/ # drw-r-x---   After fooling around for some time I think I finally got the hang of chmod and the way you set permission using this command.    But...  I still have a few questions:   What does the d at the start stand for? What's the name and use of the containing slot and what other values can it hold? How can I set and unset it? What is the value for this d? (As you only have 7=4+2+1 7=4+2+1 7=4+2+1) Why do people sometimes use 0777 instead of 777 to set their permissions?   But as I shouldn't be asking multiple questions, I'll try to ask it in one question.  In UNIX based system such as all Linux distributions, concerning the permissions, what does the first part (d) stand for and what's the use for this part of the permissions?


I typed Code under MIT documentation under CC as title of my question on Stackoverflow. The suggestions popped up showing all licensing questions as closed. Where shall the questions about licensing be asked? My original question is:  Why some project code is licensed under MIT and documentation under CC? For example

Is it appropriate to ask questions about software licenses/licensing on ? Or is the appropriate place  ? Or is there no appropriate site currently and we should suggest such a site on ?


Currently there is the  in football (soccer) taking place and the UK has 3 teams participating: England, Wales and North Ireland. It could have been 4 if Scotland qualified. It is the same for FIFA World Cups, the UK always sends four teams to the qualifications.  The UK seems to be the only country in the world which has 4 football teams even though it is considered as one country almost everywhere.  Why does the UK / why is the UK allowed to send more than one team to international football tournaments? Is it actually the same for other sports?  I already asked almost the same question on , and the answers see the reasons in history. However, there are many countries who have a similar history like the UK of smaller uniting states.

Why is it that, in different sports, athletes represent different "countries"?  In football, curling, rugby (both union and league), and other sports, there are England, Scotland, Wales, and Ireland teams;  In other sports, such as tennis, swimming, and athletics, there's only a single Great Britain team instead.   In some sports there are different national teams, in other sports only a Great Britain team.


Consider the series,  $$\sum \frac{1}{(n(x+\pi))^2}, \;x\in(-\pi,\pi)$$   I want to examine whether the series converge uniformly or not.  Efforts:  Let's assume on the contrary that convergence is uniform, then $f_n(x)=\frac{1}{(n(x+\pi))^2}\to 0$ uniformly  Now take $a_n=-\pi+{1\over n}$  $f_n(a_n)=\frac{1}{(n(-\pi +{1\over n}+\pi))^2}$   So $f_n(a_n)\to 1$, Therefore we conclude that $f_n$ does not converge uniformly to zero.   Hence our assumption was incorrect and the originial series is not uniformlly convergent.  Thanks for reading. Is this a right way to solve?

Check that given series converges uniformly for $x\in(-\pi,\pi)$ or not  1) $\sum_{n=1}^{\infty} (\frac{x}{n})^n$  2) $\sum_{n=1}^{\infty}\frac{1}{((x+\pi)n)^2}$  first series is power series so I find the radius of convergence that comes $R=e$ which is inside the given set so I am not able to give the final conclusion. after this I were thinking to apply $M_n$ test , but I am not able to find $M_n$. Please help to solve this problem.


I want to make a register form which will be connected with database. I have a problem because after filling in the form i get exception      java.lang.NullPointerException Database.Person.getName(Person.java:18)   Database.Register.doPost(Register.java:25)   I was looking for an answer, but there are only solution in easy way ( i mean everything in one class). There is my code  Person.java  package Database;   import javax.servlet.http.HttpServletRequest;  public class Person {     private String name;     private String surname;     private String email;     private String employer;     private String getKnow;     private String hobbies;      HttpServletRequest request;       public String getName() {         return request.getParameter("name");     }      public void setName(String name) {         this.name = name;     }      public String getSurname() {         return request.getParameter("surname");     }      public void setSurname(String surname) {         this.surname = surname;     }      public String getEmail() {          return request.getParameter("email");     }      public void setEmail(String email) {         this.email = email;     }      public String getEmployer() {         return request.getParameter("pracodawca");  }      public void setEmployer(String employer) {         this.employer = employer;     }      public String getGetKnow() {         return request.getParameter("getKnow"); }      public void setGetKnow(String getKnow) {         this.getKnow = getKnow;     }      public String getHobbies() {         return request.getParameter("hobbies"); }      public void setHobbies(String hobbies) {         this.hobbies = hobbies;     }   Register.java  package Database;  import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Statement;  import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  @WebServlet(urlPatterns = "/Register") public class Register extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response)             throws ServletException, IOException {     response.setContentType("text/html");     PrintWriter out = response.getWriter();      Person person = new Person();     String name = person.getName();     String surname = person.getSurname();     String email = person.getEmail();     String nameC = person.getEmployer();     String getKnow = person.getGetKnow();     String hobbies = person.getHobbies();           try {             Class.forName("org.postgresql.Driver");             Connection connection = DriverManager.getConnection(                     "jdbc:postgresql://localhost:5432/formularz", "postgres",                     "qwerty");             PreparedStatement ps = connection.prepareStatement(                     "INSERT INTO zgloszenia(name,surname, email,pracodawca, getknow, hobbies) values(?,?,?,?,?,?)");             ps.setString(1, name);             ps.setString(2, surname);             ps.setString(3, email);             ps.setString(4, nameC);             ps.setString(5, getKnow);             ps.setString(6, hobbies);              int i = ps.executeUpdate();             if (i > 0) {                 out.print("Registered successfully...");                 connection.close();             }           } catch (Exception e) {             e.printStackTrace();         }     }      }

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?


If $T:V\mapsto V$ is a linear transformation, such that $\operatorname{Rank}(T) < n$, where $n$ is the dimension of $V$. Prove that $\det(T)=0$.

I would like to know in particular whether a full rank matrix necessarilly has a determinant equal to/different from zero. Also, would the answer change based on the matrix being squared or not?


I was studying a solution to a problem and this result was given without any explanation: If $X\sim{N}(0,I_n)$ & A is a symmetric positive definite matrix, $$ \int_X\exp\left(-\frac12X'AX\right)dX=(2\pi)^\frac{n}2{\lvert{A}\rvert}^{-\frac12} $$ How can I prove this proposition?

Let $A$ be a positive definite real $n\times n$ matrix. How can I prove that $$ \int_{\mathbb{R}^n}\mathrm{e}^{-\langle Ax,x\rangle}\text{d}x=\left|\,\det\left(\pi^{-1}{A}\right)\right|^{-1/2}=\pi^{n/2}\lvert\,\det A\rvert^{-1/2}\!, $$ where $\langle\cdot,\cdot\rangle$ denotes the inner product in $\mathbb R^n$, i.e. $\langle x,y\rangle =x^Ty$.


I am able to run Geometric Network Trace by using following ArcPy script but I also need to add Trace result into the map. Can you please let me know how I can add the result(graphic/geometry) to the map.  import arcpy  arcpy.env.workspace = r"E:/Utility/Sample/Montgomery.gdb" # Local variables: G_N = "E:/Utility/Sample/Montgomery.gdb/Water/Water_Net" Flag = "E:/Utility/Sample/Flag.shp" traceOut = "traceOut_Net"  # Process: Trace Geometric Network arcpy.TraceGeometricNetwork_management(G_N, traceOut, Flag, "TRACE_UPSTREAM", "", "", "", "", "", "NO_TRACE_ENDS", "", "", "", "AS_IS", "", "", "", "AS_IS") print "Trace Done"

Using ESRI Tutorial Data for Utility Network Tracing (Montgomery.gdb) which is a File Geodatabase and following Arcpy script  I am not getting any erro on running the script to find the path between two points in Flag (point) layer  # Import arcpy module import arcpy # Local variables: gnVersionFDS_Net = "E:/Montgomery.gdb/Water/Water_Net" Flags = "E:/Montgomery.gdb/Water/Flags" gnVersionFDS_1 = "gnVersionFDS_1_Net" # Process: Trace Geometric Network arcpy.TraceGeometricNetwork_management(gnVersionFDS_Net, gnVersionFDS_1, Flags, "FIND_PATH", "", "", "", "", "", "NO_TRACE_ENDS", "", "", "", "AS_IS", "", "", "", "AS_IS") print "The Proccess Done"   I added the Flag layer manually to the Dataset and it has two points as     again, I am not getting any error but I am not seeing any layer and path to be generated or added to somewhere. Can you please let me know what I am doing wrong or how can I make this rum properly?     Update   I try to copy the output as a shapefile using this ArcPy  arcpy.Copy_management(gnVersionFDS_1, "C:/data/path.shp")   but I am getting  this error now


I can't find a way of copying n-depth jagged array by value (not by reference).  Here's the code i wrote for copying jagged array of depth 3:      public static T[][][] Clone_Arr<T>(T[][][] arr)     {         int length1 = arr.Length;         T[][][] arr2 = new T[length1][][];          for (int i = 0; i < length1; i++)         {             int length2 = arr[i].Length;             arr2[i] = new T[length2][];              for (int j = 0; j < length2; j++)             {                 int length3 = arr[i][j].Length;                 arr2[i][j] = new T[length3];                  for (int k = 0; k < length3; k++)                 {                     arr2[i][j][k] = arr[i][j][k];                 }             }         }          return arr2;     }   But I just can't figure out how to write a general func that will make a copy of a jagged array of n-depth.  Any help will be appriciated  I tried doing the following:      public static T[] Clone_Arr<T>(T[] arr)     {         int length = arr.Length;         T[] arr2 = new T[length];          if (arr.GetType().GetElementType().IsArray)         {             for (int i = 0; i < length; i++)             {                 arr2[i] = Clone_Arr<T>(arr[i]);                 // here i encounter a compilation error: cannot convert from T to T[]             }         }         else         {             for (int i = 0; i < length; i++)             {                 arr2[i] = arr[i];             }         }                    return arr2;     }

I want a true deep copy. In Java, this was easy, but how do you do it in C#?


When i create a Suzanne monkey in a new file i put subdiv modifier at 3 and try to grab a vertex, it's slow a bit. But when subdivided by 4 in the modifier it's very slow. The viewport is slow in rotation and moving even slower in 5 the subdivision modifirer. My machine can't work with more than 30 thousands verts without slowing down All of that just in edit mode, completely unusable. I tried windows 10 and 8.1 with different drivers and tried blender 2.8 and 2.79 all has the same problem.

Essentially, my problem is that i am trying to render a scene, however, blender crashes on me early during the render. I only have about 14 total objects in the scene. (It's not that complex) I tried to render a different blender file which was bigger than the one that i am having problems with, and the scene renders just fine. There is no difference in the render presets for both of these files. However, i still cannot render the other scene. It gets to preparing scene data, but then it crashes.  Thank you.


A committee of four people, containing at least one man and one woman, must be chosen from four men and three women. How many different committees are possible?  Is the right answer 34?  (7x6x5x4x3)/(1x2x3x4) - 1

A committee of four people, containing at least one man and one woman, must be chosen from four men and three women. How many different committees are possible?  I dont really now how to solve this. I tried solve them by counting them in groups. but thats not really the right way I guess. Can anyone give me a clue to solve this.


As a newbie, I am quite confused how open source software is can/be licensed. I know of licenses like GNU public, Apache, and others.   What is the procedure to license a open source software by developer? What considerations should be made? What choices do I have?

I'm a software engineer, not a lawyer, and my university doesn't offer any courses geared toward licensing software. In fact, their law-related courses are lacking (but slowly growing in number). Where can I go to learn about open-source licenses and how to choose them?


Yesterday, I created a bootable USB using UNetbootin. I created it with Windows7.iso file. It was successful.   The problem is when I booted my USB onto computer, it just show me this window without proceeding to Windows 7 installation.     After that, I pressed Tab key. Then this screen appeared :     To be honest, I didn't got any ideas what to do. Is there any commands to run in this window ?

What I need to achieve is   Create a Bootable USB drive from Windows 7 iso image using a Mac running. Use the flash drive to boot and install windows on a PC (not Mac)   What I'm looking for is an app like  but one that can run from OS X. This app make a bootable flash drive from a Windows iso image. I found a mac alternative to WinToFlash a while ago, but I don't remember the name.  All I can find is questions about making a bootable usb from a mac to a mac. I want to repair a Windows PC that doesn't startup but I have a working Mac computer, the target computer is a PC (not Apple).  A PC can't boot from a USB created with bootcamp which have MBR based BIOS.  UNetbootin doesn't seems to work with Windows iso's just Linux iso's.  P.S. the target PC have BIOS, it doesn't have UEFI.


I got function which is converting UNIX time to DaTime which is working great anyhow now I need function to convert from DateTime to UNIX timestamp but something is wrong with this because when I am passing DateTime somehow the last 3 digits are not shown for instance I have this timestamp: "1300124700345" which is equal to: 14.03.2011 5:45 PM. When i pass that to my function I am retrieving: "1300124700" - 3 last digits dissaperd.  static readonly DateTime UnixEpoch =         new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);  public static long ToUnixTime(DateTime date) {     return Convert.ToInt64((date - UnixEpoch).TotalSeconds); }

There is this example code, but then it starts talking about millisecond / nanosecond problems.  The same question is on MSDN, .  This is what I've got so far:  public Double CreatedEpoch {   get   {     DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();     TimeSpan span = (this.Created.ToLocalTime() - epoch);     return span.TotalSeconds;   }   set   {     DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();     this.Created = epoch.AddSeconds(value);   } }


I've encounter few question in SO which are not related to programming, I couldn't find a proper reason to make it off-topic. Under Flagging -> Closing -> Off-topic there are various options like  - Question must describe problem, should demonstrate a minimal understanding of the problem being solved but there are no such options like Offtopic as not related to programming. Am i looking at the wrong place ? Or should it be flagged in a different way ?  Probably what I am looking for is an option to say "this is off-topic as it is not related to programming" and that's it ... no custom message (as there is separate place to put them)

I have less than 3000 rep on StackOverflow. Now that the new closing changes are live, I cannot supply a custom off topic message:    I can enter a custom off topic flag message without issue here on meta, though it only has three canned off topic reasons, rather than five.  I'm not sure if this is the same for users with enough rep to vote to close directly, but the lack of a custom message eliminates the ability to use the correct flag reason in some cases.  For example, I wanted to flag , which is simply off topic on SO. However, I can't use a custom message, and none of the canned ones are appropriate.    appears to be the most up to date official information on custom reasons, and indicates that they are remaining in play for now.  supports that.  If this is by design, how should I flag such questions? This is not a case worth bothering the mods over, so I don't want to use a custom diamond attention flag.


I start my pattern with the number $1$. Each term in the pattern is the previous term multiplied by a random real number in the set $(0, X]$, where $X$ is a real number. The pattern does not tend towards $0$, infinity, or negative infinity. Find $X$.

I was doing some software engineering and wanted to have a thread do something in the background to basically just waste CPU time for a certain test.  While I could have done something really boring like for(i < 10000000) { j = 2 * i }, I ended up having the program start with $1$, and then for a million steps choose a random real number $r$ in the interval $[0,R]$ (uniformly distributed) and multiply the result by $r$ at each step.   When $R = 2$, it converged to $0$. When $R = 3$, it exploded to infinity.    So of course, the question anyone with a modicum of curiosity would ask: for what $R$ do we have the transition. And then, I tried the first number between $2$ and $3$ that we would all think of, Euler's number $e$, and sure enough, this conjecture was right. Would love to see a proof of this.    Now when I should be working, I'm instead wondering about the behavior of this script.   Ironically, rather than wasting my CPUs time, I'm wasting my own time. But it's a beautiful phenomenon. I don't regret it. $\ddot\smile$


when i type make in my terminal to build libraries and some tests in my machine ,i get this error:  g77 -O -fno-automatic -c lsame.f -o lsame.o make: g77: Command not found make: *** [lsame.o] Error 127   Please help me out.i am unable to install g77 too!

I have just installed 12.04 LTS on my laptop and I'm kinda new in this. I am required to write some program in Fortran 77 and I need a Fortran 77 compiler. I have tried installing g77 as described in the Ubuntu website but was unable to do so. I have typed in the following in terminal:  sudo apt-get install g77   and get the following:  Reading package lists... Done Building dependency tree        Reading state information... Done Package g77 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'g77' has no installation candidate   May I know what is the problem? I have tried searching g77 in the software center but apparently it is not there. Does this mean it is not available for 12.04?  I'm currently using an Asus K43S laptop with Intel Core i5-2450M processor and my Ubuntu is installed alongside Windows.


It seems that refreshing a question's page increases its viewing count. Not every time, but under certain conditions. For example, it seems that the count increases the first time a page is refreshed after it has been loaded for the first time.  If this is happening by chance, I have to visit the nearest casino asap!  I noticed this after posting a question on StackOverflow. I wanted to see whether I had a reply, so I was hitting refresh, every now and then. The count was going up every time I hadn't looked at the page for a large (arbitrary) amount of time. And every time it was going up by 1. It's not like it had received numerous views in the meanwhile. Never did I see a jump in "viewed" of more than one. And it only has 30 something views, so it's not like it's a popular question (unfortunately for me). In all actuality, there hasn't even been a single comment on it yet, let alone an answer.  All this leads me to believe that, contrary to , there really is a buggy viewing count at play here. Unless it's a feature....  :)  FINAL THOUGHTS: As my commenters noted, this question has been addressed  and . However, I find this feature counter-intuitive and actually a hindrance to users that are trying to see whether their question had any true views. There is no point in increasing the views by taking page refresh into account. If there can be a solution that circumvents that, I would be strongly in favour of that.

Does viewing your own question add to its view count?


I'm running the Photos app on several Macs and have iCloud Photo Library enabled. One of the Macs downloads the originals as well, the others use the Optimize Mac Storage feature. But I can't seem to find out how to sync faces across the devices. In  it states the following:  Photos lets you tag people's faces in your pictures so you can find friends easily. When you use iCloud Photo Library, these faces automatically update on all your devices. iCloud doesn't automatically update changes to the names associated with Faces or the contents of the Faces photo album in the Photos app. You can tag people's faces with names on multiple Macs, but the face tags and Faces photo albums will remain unique to each computer.  Now I've read this a couple of times but I really can't figure out what this actually means; the first paragraph says "sure, it can be automatically updated on all your devices" but the second paragraph states "but it doesn't update changes". Simply put: is it, or is it not, possible to have the same faces on all my macs? And if so, what is the best approach for periodically assigning photos to faces/people? Note that I've seen a , with an appropriate response. But these do not reflect what is stated in the support article. Update 27 Sep, 2016: now with macOS Sierra and the accompanied Photos app this is still not possible. Meaning the new "People" feature is device specific and is not synched into the cloud. And is therefor useless if you have multiple devices. There is  for this as well. Update 20 May, 2017: with Photos v2.0 (3150.4.120), on macOS 10.12.5, the "Faces" feature has been renamed "People". However, it is still not possible to sync people across Macs AND iOS devices.

The new Photos updates for iOS 10 and MacOS Sierra includes a much more powerful and integrated approach to organizing photos by who's in them.  It's built around powerful, on-device facial recognition.  But once it does its automated thing (finding the faces it thinks are the same person), there's still a lot of manual merging and labeling to be done if you have a lot of photos and are as obsessive about organization as I am.  For example, if you have, say... three thousand photos of your daughter, Photos will find almost all of them, but may guess they're 5 or 6 different people.  So you have to merge the buckets that all are one person, assign them a name (so you can search by it), etc.  But unlike other changes (edits, deletions, organization into albums, etc.), manual changes to "people" data don't seem to sync at all by default.      Is there really no way to do this?  It seems bizarre that one of the flagship features Apple's touting in this Photos update doesn't play at all with what was Photos primary selling point over iPhoto - everything synced on all your devices.


I accidentally emptied the recycle bin in windows 10. How can I restore the Recycle Bin? I didn't set up the file history or backup, so I cannot restore it to the previous version. Is there a good, reliable tool? Or Can I restore it without sw?

What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:


How many roots of the equation $z^4+8z^3+3z^2+8z+3=0$ lie in the right half plane?  The hint is to apply the . I am not sure how that will go. I can take $f(z)=z^4+8z^3+3z^2+8z+3$, so that for any closed curve $C$, $$\int_C\frac{f'(z)}{f(z)}dz=2\pi i(N-P)$$ where $N$ and $P$ denote respectively the number of zeros and poles of $f(z)$ inside the contour $C$. But here we are looking at the right half plane. I can't see how to apply the result from the argument principle.

This is a question in Ahlfors in the section on the argument principle: How many roots of the equation $f(z)=z^4+8z^3+3z^2+8z+3=0$ lie in the right half plane?  He gives a hint that we should "sketch the image of the imaginary axis and apply the argument principle to a large half disk."  Since $f$ is an entire function, I think I understand that the argument principle tells us that for any closed curve $\gamma$ in $\mathbb{C}$, the winding number of $f(\gamma)$ around 0 is equal to the number of zeros of $f$ contained inside $\gamma$.  How would you go about actually applying the hint though? I am having trouble figuring out what the image of a large half disk under $f$ would look like.


How does one take multiple computers and make them act as one, such that all their processors and memory are combined now and you are running any application such that yo are running them on a single very fast computer. Such that it can be used to run virtual machines (on software like vmware).  What operating system(s) can this be accomplished with? Or what software is needed?

by now I have 10 servers for hpc, power computing oriented. My users need to launch several processes using qmake. The users are used to work with ubuntu 9.10, and the software from the repositories is switable for them.  I've deployed ubuntu 9.10 to all 10 servers (pxe rocks).  By now we work with parallel-ssh and cluster-ssh, which allows as to launch the same process to all servers. With this tools this tools the servers remain as independent but with the same software and the same launched command.  Now we would like to go to next step and see all the servers as a single one with all the resources from the other 9 as if was its resources.   The difference would be substantial in time to process and also time to design the command to launch.  Any advice on wich software to use will be very useful?  Thanks


How can I find the elements with different attributes with lxml on python ?  for example  <Form>     <Subform ind="0">         <Check ind="0">0</Check>         <Check ind="1">1</Check>         <Check ind="2">2</Check>         <Check ind="3">3</Check>     </Subform> </Form>   to retrieve the Checks I do:  tree.findall("./Form/Subform/Check")   to get the first:  tree.findall("./Form/Subform/Check[@ind='0']")   but what I want to do is something like  tree.findall("./Form/Subform/Check[@ind='0' or @ind='1']")   To retrieve the first and second only (or first and last)  How can I do that with lxml ?

I have the following sample XML structure:  <SavingAccounts>     <SavingAccount>        <ServiceOnline>yes</ServiceOnline>        <ServiceViaPhone>no</ServiceViaPhone>     </SavingAccount>     <SavingAccount>        <ServiceOnline>no</ServiceOnline>        <ServiceViaPhone>yes</ServiceViaPhone>     </SavingAccount> </SavingAccounts>   What I need to do is filter the 'SavingAccount' nodes using XPATH where the value of 'ServiceOnline' is 'yes' or the value of 'ServiceViaPhone' is yes.  The XPATH should return me two rows!! I can filter 'SavingAccount' nodes where both of the element values are yes like the following XPATH sample, but what I want to do is an or element value comparison???  /SavingAccounts/SavingAccount/ServiceOnline[text()='yes']/../ServiceViaPhone[text()='yes']/..


How can I print my strings so that there are no spaces between each output.  name_input = str(input("Please enter your name")) name_input = name_input.strip() name_input = name_input.lower() first_letter = name_input[0] first_space = name_input.find(" ") last_name = name_input[first_space:] last_name_3 = last_name[0:4] random_number = random.randrange(0,999) print("*********************************************") print("Username Generator") print("*********************************************") print(first_letter + last_name_3, random_number)`   Incorrect output: b fir 723  what I require: bfir723

In python, if I say  print 'h'   I get the letter h and a newline.  If I say   print 'h',   I get the letter h and no newline.  If I say  print 'h', print 'm',   I get the letter h, a space, and the letter m.  How can I prevent Python from printing the space?  The print statements are different iterations of the same loop so I can't just use the + operator.


so I just did a fresh install of Sierra. Then it turned out the files are needed. I erased my drive with the fastest option and didn't installed anything on it yet except the os so I think most of the data should be recoverable. What's the best possible way to recover the erased data?

I was wondering if there is a way to recover photos and things alike from a MacBook after reinstalling the OS X.  Like when you reinstall Windows there is the "Windows.old" folder and you can recover some of the data from there.


Let $\mathbb{F}_p$ be a finite field (for a prime integer $p$), and let $x_1, \ldots, x_{2p-1}$ be any sequence of elements from it. Prove that I can chose $p$ elements from this sequence such as their sum is zero.   I think there can be useful probability method. But I can't it.

Given any multiset of positive integers of size $2n-1$, is it possible to find a multisubset of size $n$ such that $n$ divides the sum of the integers in this multisubset?   This problem has been circulating for a while in my friends group and none of us has been able to solve it.  Someone in the friend group has claimed there is a solution using the Chevalley–Warning theorem, but has not actually shown us such a solution.  A multiset is a set that may contain a number more than once.


I want to get a good Fixed Focal Length Lens with wide aperture for my Nikon D5300 which is a DX Camera and while searching for lens in India there were only 4 lens for DX compared to the 44 lens for FX body. Out of the 4 one was a Fisheye Lens so I have three choices. Should I get the DX model or choose from the FX lens. The focal length that I want is only available in the FX lens The Availabe Lens are:   35mm f/1.8 85mm f/3.5 40mm f/2.8   I wanted to get the AF-S 50mm f/1.8 or 50mm f/1.4 both of which are FX lenes. I am a little particular about the 50mm - 55mm  as I feel that is the best focal length for the type of photos that I usually take. I am also open to other lens with lower focal length as I can always crop in post.   What should I do?

I have a Canon 550D which I've been using for around a year now. I really love it and have learned a great deal with this and the 18 - 135mm kit lens. But now with experience I feel the need to get some better glass. I won't be buying a new body any time soon because I figure investing in some good glass is more important.   As I have looked around, I see quite a few good used L lenses I can get in ebay for good bargain prices. But I know that the EF lenses don't have the same focal length in the cropped sensors. Is it a wise decision to buy these EF lenses or buy the cropped sensor alternatives?  I have the following lenses in mind that I am looking to buy down the line from the canon range over the next several months.  16-35mm f/2.8L, 24-70mm f/2.8L, 70-200 f/4L.  Are these apt choices for cropped sensors? I know most pros with FFs use these but I am a bit skeptic that they will serve the same purpose for me. If so what are the alternatives for this that have almost as good image quality?


My PHP server is sending verification emails when customers sign up, so that they can verify their email address. But sometimes gmail automatically disables less-secure apps, and I have to go into the settings and re-enable it so that phpmailer can connect again. Also, the emails get through for a while and then show up as spam. Is there some more modern/standard way of doing automatic emails for this purpose? I feel like phpmailer isn't working for me. Does Google have some simple API where I can just pass the recipient address and the message body?

This is a tricky one and I've always relied on techniques, such as permission-based emails (i.e. only sending to people you have permission to send to) and not using blatantly spamish terminology.  Of late, some of the emails I send out programmatically have started being shuffled into people's spam folder automatically and I'm wondering what I can do about it.  This is despite the fact that these particular emails are not ones that humans would mark as spam, specifically, they are emails that contain license keys that people have paid good money for, so I don't think they're going to consider them spam  I figure this is a big topic in which I am essentially an ignorant simpleton.