How to tell Google to ignore URL parameters and forget about any already crawled?

Is there any way we can delete Google URL Parameters? I know in webmaster tools that there is no option to delete the URL parameters that were crawled by Google, but is their any other way we can take them out of the Google search results?  We had no URL parameters in WMT showing last month and we had a good amount of organic traffic to the website.  After few changes on SEO pages, related to rel="canonical" Google has crawled about 20 URL Parameters automatically in the last month. Each URL parameter has around 7,012,505 monitored URLs. We have lost around 50% of the organic traffic.   We made some changes to edit URL parameters, but so far that has not had any effect. We are looking for a way to tell Google to ignore these parameters and forget about all the URLs that it already crawled with them.


What improvements exist between 32-bit and 64-bit Skyrim?

Regarding the new Skyrim Special Edition, I heard it will be a 64-bit version. How/what does this improve?


multiple email from email service received

I have written a trigger to send email. Whenever the trigger is fired i am getting equal no of mails which is equal to no of records retrieved.  Ex - If i am getting 3 records, three times i am receiving email. Can anybody tell me where i am going wrong -   trigger taskEmail on Project__c (after update ) {     set<String> projName = new set<String>();     list<Task__c> listTask = new list<Task__c>();      for(Project__c pro : Trigger.new) {         projName.add(pro.Name);     }      listTask = [SELECT Id,Project_Approval__c,Project_Name__c,Status__c,Task_Executioner__c FROM Task__c WHERE Project_Name__c IN : projName];     system.debug('11111' + listTask.size());     EmailTemplate et=[Select id from EmailTemplate where name='Multiple Tasks'];     List<Messaging.SingleEmailMessage> mails = new List<Messaging.SingleEmailMessage>();      Set<Task__c> setTaskName = new Set<Task__c>();     setTaskName.addAll(listTask);     List<Task__c> finalTsk = new List<Task__c>();     finalTsk.addAll(setTaskName);       if(listTask.size() > 0) {     system.debug('222222' + listTask.size());         for(Task__c con : finalTsk) {         system.debug('33333  enter for ');                if(con.Project_Approval__c =='Approved' && con.Status__c == 'Open'){             system.debug('444   enter if inside for ');              Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();             mail.setTargetObjectId(con.Task_Executioner__c);             mail.setTemplateId(et.Id);             mail.setSaveAsActivity(false);             mail.setWhatId(con.Id);             mails.add(mail);         }         system.debug('0000000');      }      Messaging.sendEmail(mails); } }


Work done by moving up an inclined plane

Suppose an object is pushed up a smooth inclined plane from ground level to a point h above the ground with force F. The angle of inclination is A. How much work is done?  To push an object up a smooth inclined plane, one must overcome the force of gravity which causes the object to slide down the plane. Hence, the force F=mgsinA must be applied. We can denote the distance the body undergoes as s=hsinA, then:  W=Fs=mg(sinA)^2  The answer is mgh and I know that this can be easily proven using energy conservation laws, but I want to know why my method is incorrect.


How do operators work in Java and why does this method return null?

i am studying computer science and my homework was finding the next day.  The method getNextDay() returns null and doesn't go through my If statements.  Here are the two classes that are used:  public class NextDay {             public static void main(String args[]) throws Exception {               Date dateObj = new Date(30, 3, 2016);               System.out.println("Altes Datum: " + dateObj.gibTag() + "." + dateObj.gibMonat() + "." + dateObj.gibJahr() + ".");               System.out.println("Der naechste Tag ist der " + dateObj.getNextDay().toString() + ".");            } }    public class Date {     int tag;     int monat;     int jahr;      public Date(int tag, int monat, int jahr){         this.tag = tag;         this.monat = monat;         this.jahr = jahr;     }      public Date getNextDay() throws Exception{            if(monat == 2){         // wenn Februar 29 Tage hat.         if(jahr % 4 == 0 | jahr % 400 == 0){             if(tag > 0 & tag < 29){                 return new Date(tag + 1, monat, jahr);               }             else if(tag == 29 & monat == 2){                 return new Date(tag - tag + 1, monat + 1, jahr);             }else{                 throw new Exception("Im Februar können Sie nur bis 28 schreiben!");             }            }         // wenn Februar 28 Tage hat.         if(jahr % 4 != 0 | jahr % 100 != 0 & monat == 2){             if(tag > 0 & tag < 28){                 return new Date(tag + 1, monat, jahr);               }else if(tag == 28 & monat == 2){                 return new Date(tag - tag + 1, monat + 1, jahr);             }                        else{                 throw new Exception("Im Februar können Sie nur bis 28 schreiben!");             }            }         }           if(monat != 2 & monat == 1 & monat == 3 & monat == 5 & monat == 7 & monat == 8 & monat == 10 & monat == 12 ){         if(tag <= 31 & monat <= 12 & jahr > 0){             if(tag < 31){                 return new Date(tag + 1, monat, jahr);               }             else if(tag == 31 & monat < 12){                 return new Date(tag - tag + 1, monat + 1, jahr);             }             else if(monat == 12){                 if(tag == 31 & monat == 12){                     return new Date(tag - tag + 1, monat - monat + 1, jahr + 1);                 }else{                     return new Date(tag, monat, jahr + 1);                 }             }          }             else{                 throw new Exception("Sie haben ein ungültiges Datum eingegeben!");             }          }           if(monat != 2 & monat == 4 & monat == 6 & monat == 9 & monat == 11){             if(tag <= 30 & monat <= 12 & jahr > 0){                 if(tag < 30){                     return new Date(tag + 1, monat, jahr);                   }                 else if(tag == 30 & monat < 12){                     return new Date(tag - tag + 1, monat + 1, jahr);                 }                 else if(monat == 12){                     if(tag == 31 & monat == 12){                         return new Date(tag - tag + 1, monat - monat + 1, jahr + 1);                     }else{                         return new Date(tag, monat, jahr + 1);                     }                 }              }                 else{                     throw new Exception("Sie haben ein ungültiges Datum eingegeben!");                 }              }         return null;       }        public int gibTag(){         return tag;     }      public int gibMonat(){         return monat;     }      public int gibJahr(){         return jahr;     }              public String toString(){         return this.tag + "." + this.monat + "." + this.jahr;     } }


Is $n_{\rightarrow\infty}\overline{\frac{n}{\phi (n)}}$ unbounded?

Does a $\limsup_{n\to\infty}$ exist for $\overline{\dfrac{n}{\phi (n)}},$ where $\phi$ is the Euler totient function, and the overbar represents the mean.  Of course $\dfrac{n}{\phi (n)}$ is unbounded, as it grows like $e^{\gamma } \log (\log (x))+\dfrac{\text{c}}{\log (\log (x))}$ for some $c\approx 3,$ where $c\rightarrow 0$ as $n\rightarrow \infty,$ but I was wondering whether the set of (mostly, priomorial multiples) is dense enough to impose a limit on the function.  Numerical tests suggest $\limsup_{n\to\infty}\overline{\dfrac{n}{\phi (n)}}\approx 2,$ but I can't find any references to the subject. Is this realistic, or is the function unbounded?


Normally I don't use backslashes in my strings because it complicates things. In this case I don't have a choice as a black slash \  is within a token ive been given and I'm trying to pass in a url request.  Here is an example of what I'm seeing, ive tried double quotes, using repr() , escaping it but the results still show either double \ or something that doesnt represent the key.  token ="ABC\$DEfg" headers = {'content-type': 'application/json', 'Authorization': 'TOK:'+token+'', 'Accept': 'application/json'}  print ('Headers are = {0}'.format(headers))   Even though I used double quotes this is the result when I try to run the script above :  Headers are = {...'Authorization': 'TOK:ABC\\$DEfg'}   It should be ABC\$DEfg not ABC\$DEfg'  How best should I be inserting token into my request and maintain a normal single back slash. Also the token can change so I would like way to wrap the variable correctly


Euclid's Lemma and $\gcd(a,b)=1\Rightarrow \gcd(a^n,b^k)= 1$

I'm solving some problems in Apostol's Intro to Analytic Number Theory. He asks to prove  $$(a,b)=1 \wedge c|a \wedge d|b\Rightarrow (c,d)=1$$  My take is  $$\tag 1(a,b)=1 \Rightarrow 1=ax+by$$  $$ \tag 2 c|a \Rightarrow a=kc$$  $$\tag 3d|b \Rightarrow b=jd$$  $$(1),(2),(3) \Rightarrow 1=ckx+djy=cx'+dy'\Rightarrow (c,d)=1$$  Is this correct or is something missing?  I intend to use something similar to prove   $$\eqalign{   & \left( {a,b} \right) = 1 \wedge \left( {a,c} \right) = 1 \Rightarrow \left( {a,bc} \right) = 1  \cr    & \left( {a,b} \right) = 1 \Rightarrow \left( {{a^n},{b^k}} \right) = 1;n \geqslant 1,k \geqslant 1 \cr} $$  so I'd like to know.


Stack Overflow in ES, PT, RU, JP have mixed-language descriptions

The international Stack Overflow sites in Spanish, Portuguese, Russian, and Japanese seem to have a bug in their quick site descriptions (under their titles), for they all start with the word  For...  in English, instead of their respective languages As an example, the Spanish Stack Overflow site description is:  For programadores y profesionales de la informática  Obviously, this isn't something too big of a deal, but since they offer those sites in their respective languages, it would be nice if this issue were fixed. You can see this under "More communities" in the top bar.    You can also see this on the  page, where the descriptions begin with  Q&A for...


What is the difference between:     The package will be delivered in two days' time.   And     The package will be delivered within two days.   Are they the same or different?


A for loop like for (T i = a; i < b; i++) {     // do something }  looks quite normal, right? On a second glance, you'll notice T instead of a primitive datatype - a generic type. Still shouldn't be a problem, you will think. T could be anything,   not limited to   a number (a string, even a complex object), as long as it is comparable and enumerable (i.e. you need to apply the constraint where T: IEnumerable, IComparable to it). Because of the fact that it is not limited to numbers, and since Eric gave an answer which is applicable to any type of object I don't believe this question is a duplicate of the question  But back to this question: I thought the same way, then I started playing around a bit with that and tried to write something like IEnumerable<T> Numbers<T>(T a, T b) where T: IEnumerable, IComparable {     for (T i = a; i < b; i++)     {         yield return i;     } }  to implement a number generator which can be used for double, int, ... which would be a generic for-loop. The constraints IEnumerable and  IComparable are just there to tell the compiler that elements of this type can be enumerated and compared (because of the i < b expression in the for loop and the increment), and if C# would have that,  would be a quite useful constraint, too (which would then implicitly be comparable and enumerable of course). To my surprise, this example doesn't compile, it generates the following errors:  CS0019: Operator '<' cannot be applied to operands of type 'T' and 'T' CS0023: Operator '++' cannot be applied to operand of type 'T'  The reason seems to be that there is no constraint for numerics, but there doesn't seem to be any practical solution available, as some of the answers  are explaining. Note: A similar (non-generic) version of this does compile: IEnumerable<double> Numbers(double a, double b) {     for (var i = a; i < b; i++)     {         yield return i;     } }  IEnumerable<int> Numbers(int a, int b) {     for (var i = a; i < b; i++)     {         yield return i;     } }  If you have both, you can invoke it like var intNumbers = Numbers((int)1, 10); var doubleNumbers = Numbers((double)1, 10);  and due to the signature of the parameters the correct version is chosen.  In essence, the questions are: 1. Is it possible to write a generic function as the one which can be invoked like var intNumbers = Numbers<int>(1, 10); var doubleNumbers = Numbers<double>(1, 10);  as shown in my first example? (I am not sure about the correct constraint, I thought that where T: IEnumerable, IComparable would do because you need to compare i < b and you need to iterate to the next bigger number). 2. a) How can I write a generic constraint that will allow me to increment and compare variables of type T? 2. b) If there's no such constraint, is there a way to simulate a for-loop with generic arguments? 3. How can a for-loop be made generic?


Failed to Execute if Block Statements just because of Condition Checking is always false in Android using JAVA?

can someone please help me what wrong with below written "IF CODE" this is not coming inside block everytime even the values before if is logged in console.  if(userNameString == userInstance.getUsername() && passwordString == userInstance.getPassword())  Here is the complete code: if(userInstance == null)     {         Log.i("no record found againse User Instance",""+userInstance);          Toast.makeText(getApplicationContext(),                 "User Id and Password is wrong", Toast.LENGTH_SHORT).show();         getLoaderManager().destroyLoader(arg0.getId());          }     else     {         Log.i("Record found againse User Instance 1st",""+userInstance + "userName:" + userNameString +":pass:::"+passwordString);           if(userNameString == userInstance.getUsername() && passwordString == userInstance.getPassword())         {             Log.i("Record found againse User Instance 2nd",""+userInstance);                 //Log.i("UserInstance else","" + userInstance);             SessionManager.saveLoginCredentials(context,userInstance.getUsername().toString(),userInstance.getPassword().toString());             Intent intent = new Intent(LoginActivityService.this,                     ProposalListActivity.class);             startActivity(intent);                          getLoaderManager().destroyLoader(arg0.getId());         }              }  Here is the LogCat:  02-04 22:36:39.150: I/on LoadFinished of Loader(14572): Name: kong,Password: f10343d1dc8d44c8935b356aa3f8aae2,First Name: Kong 02-04 22:36:39.150: I/Record found againse User Instance 1st(14572): Name: kong,Password: f10343d1dc8d44c8935b356aa3f8aae2,First Name: KonguserName:kong:pass:::kongkong  EDIT: There was some logical problem the password i was getting from webservice is encoded instead of text and i was comparing the text with encoded value thats why the block of if statements were not executed.*


The following is a question from the university entrance examination held in 1994 using the DNC Japan Test. Can you tell the difference between rice grown in Japan and ?  American one, 2) American rice, 3) one of America, 4) rice of America  Correct answer is 2. I'd like to know why 4 is incorrect. If there were another option 4', 4') the rice of America would 4' be also the correct answer? The reason why I think 4' might be right is that there is a book called The Wines of America by Leon D. Adams.


I have a kind of problem. I am trying to hard-link all my dotfiles [files that customize certain apps] in one folder for ease of use, called ~/dotfiles/ , but multiple programs that I have, have entire directories for that. Some are in .config, some just have a directory at the home folder, so I tried to check whether I could hard-link a directory.  After looking into it, I saw all the problems, warning, etc. about hard-linking directories, and why it's a giant nono. So I'm fully discouraged from hard-linking directories, however, I still need to do it somehow.  I found a way around this, which is by creating directories within ~/dotfiles/ and hardlinking the contents of the directories INTO those created ones, but that immediately hit a brick wall called boredom and repetition. A bunch of programs had multiple dirs, some with nested directories, and I didn't feel like spending a lot of time creating directories just so that I'm able to hard-link config files.  All I'm wondering is this. Is there a way to simulate a hard-link?   For example, I have a directory called ~/Testconfig/, and I want to hard-link it into ~/dotfiles/. Theoretically, a hardlink would place a directory in ~/dotfiles/ with all of it's contents, including its files and its nested directories.  Is there a way to achieve that without actually creating a hardlink?  My idea is that a bash script could be made that automates all of this, but I know next to nothing about bash, so that would be difficult.


The Electromagetic Tensor and Minkowski Metric Sign Convention

I am trying to figure out how to switch between Minkowski metric tensor sign conventions of (+, -, -, -) to (-, +, +, +) for the  $F^{\alpha \beta}$.  For the convention of (+, -, -, -) I know the contravariant and covarient forms of the electromagnetic tensor are: $$ F^{\alpha \beta} =     \begin{bmatrix}     0 & -\frac{E_{x}}{c} & -\frac{E_{y}}{c} & -\frac{E_{z}}{c} \\     \frac{E_{x}}{c} & 0 & -B_{z} & B_{y} \\     \frac{E_{y}}{c} & B_{z} & 0 &  -B_{x} \\     \frac{E_{z}}{c} & -B_{y} & B_{x} & 0 \\     \end{bmatrix} $$ and $$ F_{\alpha \beta} = \eta_{\alpha \mu} F^{\mu v} \eta_{v \beta} =      \begin{bmatrix}     0 & \frac{E_{x}}{c} & \frac{E_{y}}{c} & \frac{E_{z}}{c} \\     -\frac{E_{x}}{c} & 0 & -B_{z} & B_{y} \\     -\frac{E_{y}}{c} & B_{z} & 0 &  -B_{x} \\     -\frac{E_{z}}{c} & -B_{y} & B_{x} & 0 \\     \end{bmatrix}. $$  Now for the convention of (-, +, +, +) are the contravariant and covariant forms of the electromagnetic tensor just switched from above along with signs?:  $$ F^{\alpha \beta}=      \begin{bmatrix}     0 & \frac{E_{x}}{c} & \frac{E_{y}}{c} & \frac{E_{z}}{c} \\     -\frac{E_{x}}{c} & 0 & B_{z} & -B_{y} \\     -\frac{E_{y}}{c} & -B_{z} & 0 &  B_{x} \\     -\frac{E_{z}}{c} & B_{y} & -B_{x} & 0 \\     \end{bmatrix} $$ and $$ F_{\alpha \beta} = \eta_{\alpha \mu} F^{\mu v} \eta_{v \beta} =     \begin{bmatrix}     0 & -\frac{E_{x}}{c} & -\frac{E_{y}}{c} & -\frac{E_{z}}{c} \\     \frac{E_{x}}{c} & 0 & B_{z} & -B_{y} \\     \frac{E_{y}}{c} & -B_{z} & 0 &  B_{x} \\     \frac{E_{z}}{c} & B_{y} & -B_{x} & 0 \\     \end{bmatrix}~? $$  Basically, I am trying to figure out how to switch between the two sign conventions.


Can I use a Bash variable in a sed command?

I'm trying to execute a sed command with "-n" option.  for i in 1 2 3 4 5 ; do maas maas nodes list | grep hostname | cut -d\" -f4 | sed -n '$ip'; done   I want it to run  sed -n '1p' then sed -n '2p' and so on.  Any idea?


Help with proving this combinatorial identity?

so I'm currently in a combinatorics course, and I am struggling immensely with proofs, especially with combinatorial identities. I have the following identity I am trying to prove:  $$\sum_{k = 0}^{m} (-1)^k {n \choose k} =  (-1)^m {n-1 \choose m} $$  I tried to prove this algebraically by expanding the LHS and the RHS but it ended up being messy, so I gave up on that. In terms of a combinatorial proof, I have no clue what this identity is trying to say.   Any guidance towards both a combinatorial proof and an algebraic proof would be appreciated!


HP 15-dw0037wm - Realtek RTL8821CE 802.11ac PCI-E Wireless Network Adapter Issues - Not Working in Linux - Ubuntu/Debian/Pop OS!

I have an issue getting the following laptop's wireless adapter working properly with Linux(AKA Ubuntu). HP 15-dw0037wm - Realtek RTL8821CE 802.11ac PCI-E Wireless Network Adapter I was wondering if someone could provide a clear, step by step, guide that would allow me to get this adapter working properly. It also functions as a Bluetooth receiver and I would really like for both the Wireless Connection Functionality and the Bluetooth Connection Functionality to work as intended. Could someone shed some light as to why this card isn't working properly after a fresh install like almost every other wireless adapter I've ever had to work with when installing Linux? Is the adapter just too new? Is it using some proprietary design and isn't Linux friendly? If you need any info from me just let me know and I will try to collect that info for you as soon as possible. Any help would be greatly appreciated. Thank you! ==== Edit 12/31/2020 - Apparently canonical have created a package they maintain for this scenario. To install it simply open a terminal and enter the following command... sudo apt update && sudo apt install rtl8821ce-dkms  I will try this and let you know how it goes. Remember I was trying to get both wi-fi and bluetooth working so if one works but not the other, that means I am still having issues and this isn't working. Anyway I will let you guys know what happens in a few days when I touch the laptop again to work on it. ==== Edit 12/31/2020 #2 - After reading up some more I found this thread...  In this thread they reference this package...  So I will try installing this package as well to see if that corrects the issue and provides both Bluetooth and Wi-Fi functionality. sudo apt update && sudo apt install linux-firmware && sudo apt install firmware-realtek && sudo apt autoremove && sudo reboot  I will let you guys know how it goes in a few days when I can try it.


ECDSA: Why is SigningKey shorter than VerifyingKey

Total Crypto Noob here.  I was wondering why in ECDSA the Signing Key is so much (half of) shorter than the Verifying key?  Lets look at some python code:  import ecdsa import binascii signing_key = ecdsa.SigningKey.generate(curve=ecdsa.SECP256k1) verifying_key = signing_key.get_verifying_key() print(binascii.hexlify(signing_key.to_string())  print(binascii.hexlify(verifying_key.to_string())  b'662ab496304f2d99aca32d813dbcba3c3ae10ab2b3359fbe43b05ee40b458cec' b'6632feae645469c16cb31d7e1364cae247bd4322040d7089476614399bcf59b2fccf5060686ab09ee64e1b768ba037184e9a87001a4897a745721f99000b44ee'   lets assume I send verifying keys over the network or store them someware, it would be nice if they were not so long. Is there a way to compress them?  I assume it would be really bad to use the keys vice versa, but I don't understand why.


How can I recover a deleted file on Android?

I just deleted a file on my Nexus S that I really need back. (It was actually part of an app using a sqlite database that did a drop table when upgrading to a new version.)  Presumably I need to root the phone first (which I hear is easy on Nexus phones) but am I in a catch-22 here? Namely, does rooting the phone mean wiping/overwriting the partition where the data lives?  If not, what do you recommend for data recovery tools? Presumably the file was just unlinked and not actively overwritten (per usual when "deleting" a file) so technically the data must be there...


Is there a Cosmic Gravitational Background Radiation (CGBR)?

The recent discovery by the LIGO made me wonder about this.  We know that there exists a CMBR, Cosmic Microwave Background Radiation, a blanket of electromagnetic energy covering the universe, made by the Big Bang.  But, the big bang was an explosive event. The huge "shockwave" made by it sent ripples in space time. (Primordial gravitational waves)  Wouldn't these ripples flood the universe creating sort of a Cosmic Gravitational Background Radiation (not exactly radiation)?  If such waves do flood the universe, couldn't a much more sensetive version of LIGO be able to detect this and use it as a contrast to create "gravitational telescopes"?


How can i let my rigid body simulations continue for longer?

My timeline will only go upto 350 frames then the simulation will end. I have tried to increase the end time for it but it will not work is there another way i can do this?


Simple/elementary explanation for $\mathbf{3} \otimes \mathbf{\bar{3}} = \mathbf{8} \oplus \mathbf{1}$?

I am preparing a talk on the Eightfold Way, and am attempting to explain the spectra of the light mesons/baryons via representation theory. It will be delivered to students who have never seen representation theory before. I understand the arrangement of particles can be explained by reps of $\mathrm{SU}(3)$, e.g. the light mesons ($\mathrm{u}$, $\mathrm{d}$, $\mathrm{s}$) correspond to the representation $\mathbf{3} \otimes \mathbf{\bar{3}}$ of $\mathrm{SU}(3)$, which I understand decomposes as $\mathbf{3} \otimes \mathbf{\bar{3}} = \mathbf{8} \oplus \mathbf{1}$.  Is there a simple and elementary way to derive this decomposition, i.e. without needing to know a lot of Lie groups/rep theory?  I've seen Young diagrams used as a tool, but still have not been able to understand how they work. If someone could give a self-contained explanation, or direct me to where I could find one, that would be great. I know group theory and surface-level stuff, and am willing to blindly accept some facts [e.g. that there exist representations $\mathbf{1}$, $\mathbf{3}$, $\mathbf{6}$, $\mathbf{8}$ of $\mathrm{SU}(3)$], but I'd like to give some motivation for the formula $\mathbf{3} \otimes \mathbf{\bar{3}} = \mathbf{8} \oplus \mathbf{1}$ without just handwaving it.  Same for the baryons: $\mathbf{3} \otimes \mathbf{3} \otimes \mathbf{3} = \mathbf{10} \oplus \mathbf{8} \oplus \mathbf{8} \oplus \mathbf{1}$.


How to normalize the output of a neural network

We have a VGG16 network trained from scratch with a Sigmoid output function. We have 6 classes and the usual output looks like this:  scores': [6.494849458249519e-08, 1.8738395510808914e-06, 3.010111981893715e-07, 0.0, 0.0, 0.8633317947387695]   The problem is that the output value is very low in each class, I would like to have a normalized output that sums to 1.0 Thanks


VirtualBox 4.3 on Ubuntu 13.10 unable to run VM

Like   I am also having a problem I keep getting the following error :  Trying to register the VirtualBox kernel modules using DKMSError! Your kernel headers    for kernel 3.8.0-25-generic cannot be found. Please install the linux-headers-3.8.0-25-generic package, or use the --kernelsourcedir option to tell DKMS where it's located  ...failed!   (Failed, trying without DKMS) Recompiling VirtualBox kernel modules ...failed!   (Look at /var/log/vbox-install.log to find out what went wrong) Processing triggers for ureadahead ...   I am unable to start a Virtual Machine I installed from repository. Any ideas ?  EDIT:  When I start a vm I get :  Kernel driver not installed (rc=-1908)  The VirtualBox Linux kernel driver (vboxdrv) is either not loaded or there is a      permission problem with /dev/vboxdrv. Please reinstall the kernel module by executing  '/etc/init.d/vboxdrv setup'  as root. If it is available in your distribution, you should install the DKMS package     first. This package keeps track of Linux kernel changes and recompiles the vboxdrv kernel     module if necessary.   EDIT  The same errors with VirtualBox4.2 EDIT  sudo apt-get install linux-headers-3.8.0-25-generic  Reading package lists... Done Building dependency tree Reading state information... Done Package linux-headers-3.8.0-25-generic 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 'linux-headers-3.8.0-25-generic' has no installation candidate   EDIT UPDATE  Manually updated the kernel from 3.8.0.25 to 3.10.0-031000-generic and now it all works !


I'm a Sony VAIO User. I bought it from internet. It came to me with a preinstalled Windows 8. There was no serial key on any surface of laptop and i was given no CD or any other stuff, just the laptop; so I had no serial key.  Like a month ago, my harddisk crashed, and needed to replace it; and temporarily a pc service installed Windows 10 because of we didn't know the serial key. But as you know, it's not compatible with a lot of things. Now I want to install Windows 8 again and update to 8.1.. etc.  I found my serial key within a help of a program. I checked it by microsoft technical support chat and they said it's an OEM version.  My questions are:   Is it possible for me to reinstall windows 8 with that serial key? If yes, how?    (When I try to install download windows 8 from this site , after i enter my key, it says "This product key cannot be used to install a retail version of Windows 8").


Ubuntu 16.04 do not detect monitor samsung 19"

I have Ubuntu 16.04 installed.  I have an Intel G33/G31 Express Chip in my Foxconn desktop computer. The Ubuntu does not detect my analogic monitor Samsung SB19B300B.   This monitor has 1366 x 768 max resolution.  In the System setting Display, Ubuntu only shows me the options 1024 x 768 (4:3) and 800 x 600 (4:3) for resolution and shows me "Unknown display" but DOES NOT show me 16:9 relations for 1366 x 768 resolution (60 Hz).   When I run the recommendations of "How to set a custom resolution?" I obtain this results:  root@tomas-OEM:/home/tomas# cvt 1366 768 60 # 1368x768 59.88 Hz (CVT) hsync: 47.79 kHz; pclk: 85.25 MHz Modeline "1368x768_60.00"   85.25  1368 1440 1576 1784  768 771 781 798 -hsync +vsync  root@tomas-OEM:/home/tomas#  xrandr --newmode "1368x768_60.00"   85.25  1368 1440 1576 1784  768 771 781 798 -hsync +vsync  root@tomas-OEM:/home/tomas# xrandr --addmode VGA-0 1368x768_60.00 xrandr: cannot find output "VGA-0"  root@tomas-OEM:/home/tomas# xrandr | grep -e " connected [^(]" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/" VGA1  root@tomas-OEM:/home/tomas# xrandr -s 1368x768 Size 1368x768 not found in available modes   Use as a temporary solution while finding a better way:  I create a script with the commands:  xrandr --newmode "1368x768_60.00" 85.25 1368 1440 1576 1784 768 771 781 798 -hsync + vsync xrandr --addmode VGA1 1368x768_60.00 xrandr -s 1368x768   I set it as executable and I add it to the "applications at startup"  But I do not think it's good because the start takes more time and works like OS windows performance!


I have a point layer (bus stops), and I want to select the ones that are going to be changed (they have a common attribute to select them). I copy the selection (either ctrl+c or with the menu button) and choose the option "Edit > Paste Features as > Memory vector layer"  I choose the correct CRS (i've tried other CRS) and i create a memory vector layer (i've also tried to save it as a vector layer).  And the result is that the layer I get doesn't have any attribute:    I've done this a lot of times, and I've never had this issue. But this time, it doesn't work.  Just to clarify, the layer only has 300 points more or less, so it is not a limit problem. I've also tried to create a layer from selection on other layers, but still the same problem. It seems something has broken (yesterday everything worked fine).  Any idea why this is happening?   (QGIS 2.8.3 on Windows 7)


There are many questions about git, so I google for a while before I asked here. I've not find any useful info.  Just make it easy,  cat a.txt >> c.txt git add . cat b.txt >> c.txt   how to undo the last cat command.  Note here is just a simple to illustrate what I want, there are lot of modify before and after the git add.  The question may be duplicate, or the title is not proper, may someone helps?


How to check if a particular argument is supported in parser.parse_args()?

For example, How can I know whether there is an argument like args.manual_selection in args (args = parser.parse_args())


Draw power from a portable mobile charger to power circuits

I usually power my beginner prototype circuits using mb102 power supply board, but it needs an external elimeter to draw power and then regulate it.  I was looking for a portable solution for my 5 volt and 3.3 volt circuit needs and came up with using a portable battery charger for mobile phones.  I tried powering up a simple transistor and LED circuit with it but it wouldn't power-up.   I feel that there is some load sensing circuit in the portable charger which doesn't detect these low power circuits.  I also tried connecting different resistors to the charger, the charger outputs 5 Volts for a few seconds and then again shuts down and doesn't stay ON continuously.  It would be really comfortable to use a portable charger since it could be charged using a phone charger and would be very handy.  What can I do to make the charger output power on low loads?


Using | pipe character from a $variable makes it treat as just another argument in bash; how to escape it?

I have a bash script like this  export pipedargument="| sort -n" ls $pipedargument   But it gives the error  ls: |: No such file or directory ls: sort: No such file or directory   It seems to be treating the contents of "| sort -n" as just an argument passed to ls.   How can I escape it so that it's treated as a regular piped command?   I'm trying to conditionally set the $pipedargument. I guess I could just conditionally execute different versions of the command but still wondering if there's a way to make this work like above?


What is closure of $\Bbb Q \cap [0,1]$ ? It is subset of $\Bbb Q$ so its closure should be $\Bbb R$ but I'm confused here it is somewhere dense or everywhere dense.


Can anything other than recessional motion cause a redshift?

The question pretty much says it all. Is there any force, or circumstance, or anything that we know of that can affect the measurement of a red shift?


That the speed of light is constant for all inertial frames is the second postulate of special relativity but this does not means that nothing can travel faster than light.   so is it possible the point that nothing can travel faster than light was wrong?


Visa advice for minor person wishing to enter the UK unaccompanied

My name is Tom and I am turning 18 in 6 months. I want to go to London in the first week of May but on my visa it's written only valid if accompanied by my mother. So my question is that if a get consent letter sign from my mother, can I go to England alone?


Where should I ask my question about partition types and performance?

I have a question about partition types and their performance for an external HDD.  So is there any Stack Exchange site in which I could ask this question?  I have searched on the Internet, but I couldn't find my answers.


Featured On Meta section doesn't list MSE posts on meta sites

The Featured on Meta section of the Community Bulletin on a per-site Meta only lists its own featured posts, while the section on a main site also lists the featured MSE posts. Is it by-design? Any specific reason for this? I think it should be displayed.  Community Bulletin on a Main site:    Community Bulletin on a Meta site:


Mobile usability issues reported by Google at Search Console

Google search console reported that some pages have a Mobile Usability issues:  Clickable elements too close together Content wider than screen Text too small to read  Some details:  this is not about restrictions in robots.txt some failed pages have less than 8 resources with 550KB size total the failed pages make up a small part of the total and are random "LIVE TEST" for the same URL may fail randomly there is no network problems (packet loss/response time/DNS) with the server where site deployed this issue appeared since April 14th most of the failed pages have 90-99% mobile performance in PageSpeed Insights or Lighthouse  Lighthouse embedded in the Chrome and  haven't found a problem in mobile mode in the same pages that have an issues in Google search console. But when I use "LIVE TEST" for failed URLs in Google search console, sometimes I get a same failed result with Mobile Usability issues, where CSS file not loaded with a reason "Other error". I think this is an issues reason but I don't understand what can I do to fix it, especially if it is due to some netiquette limitation (crawl budget)


I wrote a sentence:     Figure 6(top) shows that....... while figure 6(bottom) shows....    Does this sentence look grammatically clear with using parentheses? Do I have to leave a space after number 6, before ()?


Remove `Set as desktop background` option?

Using Windows 8.1. If I need to change the desktop, I can right-click the desktop, select Personalise then Desktop Background in the lower left. This is fine because the background is usually set once and then changed infrequently thereafter.  However, Windows offers the option Set as desktop background when you right-click an image file (BMP, PNG, etc).    Since changing the background is done rarely, this seems overkill. This afternoon I accidentally clicked the option. I'd long since forgotten where the original background image was buried in my file structure (and there is no Undo!). After about an hr of searching, I eventually found the file and restored my background.  Can this option be removed from the context menu to prevent future accidents?


Not lifting your pen on the $n\times n$ grid

Does there exist $n$, and $r<2n-2$, such that the $n\times n$ square grid can be connected with an unbroken path of $r$ straight lines?   Note: This has essentially already been asked - see  MSE thread.  I am posting this question because I wanted to explicitly focus on one of the unanswered parts.  Notice that $2n-1$ is the trivial solution.  This is obtained by either spiralling towards the center, or by zig-zagging up and down.  On the  MSE thread, I posted an answer showing $2n-2$ was possible for $n\geq 3$. (this is obtained by reducing to the $3\times 3$ case)  I felt $2n-2$ should be optimal, but I couldn't think of a proof.  (Also, it is not necessarily clear that for a 100 billion by 100 billion grid you can't use some kind of cleverness to eliminate one single line)  This has been bothering me since I saw it, and I would like to know if anyone has any ideas.  Thanks,  Edit:  This is regarding an question/answer I received:  Not only are 45 degree lines allowed, but lines in any direction.  Naturally 0,45,90 seem like the best since those angles will intersect the most lattice points, and we ask ourselves "Will any optimal solution consist only of lines at these angles?".  The answer is a definite no.  Consider the  to the $10\times 10$ grid which uses 18 lines (so $2n-2$, i.e. currently optimal).  Also there is  solution to the $8\times 8 $ grid using 14 lines.  Interestingly, this solution to the $10\times 10 $ generalizes to give another $2n-2$ line solution to the $n\times n$ grid when $n$ is even.  (I found this $8\times8$ and $10\times 10$ solution on a link posted by user3123 on the  question page.  Specifically it was  link.)


Chromium not loading google related sites, youtube ubuntu ask etc

noob here having issues with google, youtube, etc not loading running 12.04 LTS.  I uninstalled and reinstalled chromium various times.  I'd hate to reinstall 12.04 as i have had issues with various programs and now everything was working fine over the last couple of months.


Windows 10 Icon not showing up on Notification Bar

Please help me for some reason the Windows 10 icon isnt showing up. I have a Windows 8.1 It dosn't show up.Also i have all my updates installed. Please Help Me. i cant reserve a copy for Windows 10 and im really worried because like this is only for a limited time so if you know anything to fix Please Help Me Asap


Turkey e-visa for Egyptian passport holder

I got the Turkey e-visa several times with my schengen visa. In the e-visa form there is a condition      I have a round-trip ticket with Turkish Airlines, Pegasus Airlines,   Onur Air or Egypt Air.   What if I am traveling from another country to Turkey or using another airlines like Nile Air form Egypt?


Exchanging of limits in case of uniform convergence.

$\lim_{x \rightarrow \infty} \lim_{n \rightarrow \infty} f_{n}(x) = \lim_{n \rightarrow \infty}\lim_{x \rightarrow \infty}f_{n}(x) $ in case of uniform convergence of $f_{n}(x)$ to $f(x)$  I used this while I was given that $f_{n}(x)$ converges to $f(x)$ uniformly. Is this correct and I was also thinking to prove this!


For $a>0$, test the convergence of the infinite series: $$\sum a^{\ln(n)}$$ Which test should be better to use here? I tried the D'Alembert's ratio test. $$\lim_{n\to \infty} {\frac{a^{\ln(n)}}{a^{\ln(n+1)}}}= \lim_{n\to \infty}a^{ln{\frac{n}{n+1}}}=a^0=1$$ So the test failed.  UPDATE: I observed that $${a^{\ln(n)}}=e^{{\ln(a)}{\ln(n)}}={n^{\ln(a)}}={{1\over n^{ln({1\over a})}} }$$Further by test of auxiliary series $$\sum \frac{1}{n^p}$$ we know that criterion for convergence is $p>1$. Here $p=ln({1\over a})$.Hence the series will be convergent when $ln(a)<-1$ i.e. when $0<a<1/e$, since $a>0$ is already given.Finally this solved my question.


Could you help me, please? In our country EL students have got special copy-books where they write new English words down (not in alphabetical order). How is it correct to call such a copy-book in English: a dictionary or a vocabulary?


How can I show downloaded apps icons on desktop

I just install ubuntu . How can ı see my spotify vs code's icons on my desktop . Is there a shortcut for it or terminal command ?


I have a script that dynamically creates Amazon EC2 instances and adds their ssh key to my ~/.ssh/known_hosts. However, whenever I need to refresh the instance by terminating and recreating it, I get obnoxious warning messages like:  @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that a host key has just been changed. The fingerprint for the ECDSA key sent by the remote host is <fingerprint>. Please contact your system administrator. Add correct host key in ~/.ssh/known_hosts to get rid of this message. Offending ECDSA key in ~/.ssh/known_hosts:94   remove with: ssh-keygen -f "~/.ssh/known_hosts" -R <hostname> Password authentication is disabled to avoid man-in-the-middle attacks. Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.   The warning is understandable, but even if I run that command to remove the old key, logging in still gives me the warning:  Warning: Permanently added '<hostname>' (ECDSA) to the list of known hosts. Warning: the ECDSA host key for '<hostname>' differs from the key for the IP address '<ip>' Offending key for IP in ~/.ssh/known_hosts:96   The solution is to manually remove that line in my known_hosts, but is there a way to automate this by running a single command beforehand?


What is the location of photo used for Windows 10 lock screen?

Where is this image from? Any help would be great!


How can I do this symbol (integral with a barre) in latex?

How can I do this symbole in latex ? (if possible with the barre of the middle more straight).


"Far away, in the heavenly abode of the great god Indra, there is a wonderful net that has been hung by some artificer in such a manner that it stretches out infinitely in all directions. In accordance with the extravagant tastes of deities, the artificer has hung a single glittering jewel in each "eye"of the net, and since the net itself is infinite in dimension, the jewels are infinite in number. If we new arbitrarily select one of the jewels and inspect it, we will discover that in its polished surface there are reflected all the other jewels in the net, infinite in number. Not only that, but each of the jewels reflected in this one jewel is reflecting all the others, so there is an infinite reflecting process occurring."    Is the number of jewels + jewel reflections countably infinite or not? How do I prove it?


Test for the convergence of the sequence $S_n =\frac1n \left(1 + \frac{1}{2} + \frac{1}{3} + \cdots+ \frac{1}{n}\right)$

$$S_n =\frac1n \left(1 + \frac{1}{2} + \frac{1}{3} + \cdots+ \frac{1}{n}\right)$$ Show the convergence of $S_n$ (the method of difference more preferably)  I just began treating sequences in school, and our teacher taught that monotone increasing sequence, bounded above and monotone decreasing sequences, bounded below converge.  and so using that theorem here.. I found the $$(n+1)_{th} term$$, $$S_{n+1} = \frac1{n+1} \left(1 + \frac{1}{2} + \frac{1}{3} + \cdots+ \frac{1}{n+1}\right)$$  and then subtracted the (n)th term from it   What I was able to get was... $$S_{n+1}-S_n = \frac1{(n+1)^2} - \frac{\left(1+\frac12+\dots+\frac1n\right)}{n(n+1)}.$$ ...but then this is where I get stucked, but i'm trying to prove that the sequence > 0(i.e Converges) or < 0 (i.e diverges).


Story about a man considering leaving an android place-holder while sneaking out on his wife

Short story about a guy thinking of leaving his spouse by substituting a lifelike android of self to cover in his absence. But when he finally decides he shouldn't follow through, he lays back down bed with his wife and when he rests his head on her chest he realizes from the sound that she has already done the switch herself, and she is off somewhere cheating on him and has left an android for him to snuggle with.  This would be an older story, I think I first read it in about 1974 or so. Most likely it was a mainstream well known sci-fi author if I was reading it in high school. The reason I am looking is I would love to find the haunting audio version of the story as read by Burgess Meredith.


grep not matching in nc output - tee gives no output

See original Q&A about grep not accepting netcat output on stderr at a .  Concise answer. I like it. Why does adding a tee on the end fail to produce any output?  nc -zvv localhost 3100-3200 2>&1 | grep succeeded | tee test.txt   Using only tee works. Using only grep works. Chaining tee after grep gives no output (console or file).  Any ideas?


I noticed a large portion of general public (who knows what square root is) has a different concept regarding the surd of a positive number, $\sqrt\cdot$, or the principal square root function.  It seems to me a lot of people would say, for example, $\sqrt 4 = \pm 2$, instead of $\sqrt 4 = 2$. People even would correct a statement of the latter form to one with a $\pm$ sign. Some also claim that, since $2^2 = 4$ and $(-2)^2 = 4$, $\sqrt 4 = \pm 2$. Some people continue to quote other "evidences" like the $y=x^2$ graph. While most people understand there are two square roots for a positive number, some seem to have confused this with the surd notation.  From an educational viewpoint, what might be lacking when teaching students about surd forms? Is a lack of understanding to functions a reason for this misconception?    Now I have noticed another  that hinted that poster was confused. Following @AndréNicolas's comment below, might these confusion really come from two different communities using the same symbol?


How can there be more than 39 stargates when each gate needs a unique "point of origin"?

It is shown in Stargate that there is a limited number of chevrons in each gate. Since we need a chevron for the origin point at the end of each "dialup", it can not be more origin planets than chevrons (e.g. 39).  Since there are obviously more than 39 planets shown on the TV show, how could the series be so long? How could it last long enough long to even Atlantis and Universe?  EDIT: Note: this is not a duplicate of  because there an estimation of the number of stargates is requested, and here the question is about how could that number be so high when you need Point of Origin chevrons and there are not so many different PoO chevrons available.


I know -X -Y options in ssh for X11 forwarding.But these options open the gui apps on my pc.But I want to open a gui application "exactly" on target machine. So please help me with this. I tried  but ended up with the following error.  No protocol specified No protocol specified No protocol specified Error: cannot open display: :0


Cannot post another question after recently posting a question

I just posted a question on Stack Overflow dealing with a specific AWS Data Pipeline configuration question. I have a second unrelated AWS Data Pipeline question I also need help with, but when I click the Ask Question button it keeps opening the edit screen for my previous question I posted.  I've tried clicking on the Ask Question button from the home page, but the same thing happens. Can I not ask two questions simultaneously within a certain time period or is this a bug? If needed, .


Export time-series MODIS 16 Day NDVI and EVI Data on Google Earth Engine

I want to extract every single MODIS 16 Day NDVI and EVI Data image on a particular area from 2000 to 2016. I was able to filter image collection but I do not know how to export every single image on the collection.  Here is my code:    // Area of interest  var AOI = ee.Geometry.Rectangle([93.8, -8.8, 109.9, 6.84]);  // Go to the center of the map  Map.centerObject(AOI, 4 )  // Find MOD13Q1.005 Vegetation Indices 16 Day Global 250 m  var modis = ee.ImageCollection('MODIS/MOD13Q1')  // Filter the collection  var image = ee.ImageCollection((modis).filterDate(ee.Date('2000-01-01'),ee.Date('2017-12-31')).filterBounds(AOI));  // NDVI dan EVI  var NDVI = image.select(['NDVI'])  var EVI = image.select(['EVI'])   //Print the image list on console  print(NDVI) print(EVI)  //Load it into map  Map.addLayer(NDVI);   I know that my code is too long and not efficient, but it helps me to read and understand it.  Can you help me to write code to export every single NDVI and EVI image on my image collection?


Are there any undergraduate research programs available online?

Is there something like an undergraduate research programme (given by a good institution) in mathematics/theoretical physics which provides a research opportunity in which I can collaborate online and leads to a publication?


Dividing space into homogeneous connected areas

Is there an algorithm (or software) for splitting a map into K connected areas such that the within-area variance of some variable is minimised, and the between-area variance of that variable is maximised?  This seems like it'd be a fairly common problem. For example, one might want to do this sort of thing if one wanted to draw homogeneous electoral districts.


MTG: Sideboard if maindeck has more than 60 cards

I did some calculation and found out, that my Living End deck (modern) might be better of with 66 cards maindeck. SB still contains of 15 cards. Depending on the match up, I'd like to cut my deck for game two down to the normal 60. The SB than would contain 15+6 = 21 cards. Is this legal?


Can I increase the number of frames in an rigid body simulation?

Every time I am making a simulation it is stopping at 250. Why? I want to make it longer..like 400 or something. Can I even do that? I tried increasing the frames at the menu bar where object mode at all those are written...I don't know what it is called since I am a noob. I even changed frame rate and frame range. It didn't work.


How can I request my question to be locked?

My question titled, , is receiving a tremendous amount of down-votes and comment criticism.  The thing is, I already understand that my question isn't so great. But every day, that question gathers more and more down-votes, and I keep losing reputation points.          I already understand that my question isn't so great, but I'm still accumulating more and more down-votes every day.   I don't want my reputation to continue draining just because of a disliked question that's been sitting there for a long time. It's like trying to fill a bowl with water, except the bowl has a large hole in it.  Is it possible to request my question to be locked? Locked questions can't be voted or commented on, although they're still accessible. I want other users to be able to read the question and its answers, but I don't want them to keep up the down-vote frenzy.


Why did Luke fail in the cave on Degobah?

In the Empire Strikes Back, just as Luke is leaving Degobah to rescue Han and Leia on Cloud City, Yoda and Ben attempt to convince him to stay and finish his training.  YODA: Luke, you must complete the training. LUKE: Ah, I can't get the vision out of my head. They're my friends I've got help them. YODA: You must not go. LUKE: But Han and Leia will die if I don't! BEN: You don't know that. Even Yoda cannot see their fate. LUKE: But I can help them! I feel the Force.. BEN: But you cannot control it. This is a dangerous time for you, when you will be tempted by the dark side of the Force. YODA: Yes, yes! To Obi-wan you listen. The cave.. remember your failure in the cave.   Why did Luke fail during his experience in the cave? Was it because he was the first to draw his sword upon encountering the image of Vader, with Yoda previously mentioning that Luke wouldn't need his weapons? Or, was it because Luke used anger/fear/hate to strike down Vader's image? Maybe a combination of both, and/or more?  After thought: If Luke didn't take his lightsaber with him, would he still have encountered Vader? If so, is it possible they would have just had a conversation? Maybe there are other Jedi who have also gone through similar trials, but had had a different, more successful experience, which could provide insight as to what would have happened with Luke should he have taken Yoda's advice and not brought his saber (and, implicitly, a different state of mind)?


Formula with numerator and denominator of a fraction in display mode

I have the following formula and I want the nominator and the denominator to appear in display style. I use \everymath{\displaystyle} so I don't understand why they are not in display mode. How can I make this happen? Also why doesn't \everymath{\displaystyle} do the trick? Thanks!  C=\frac{\iint \vec{E}\epsilon\cdot \vec{dS}}{-\int_{A}^{B}\vec{E}\cdot\vec{dl}}


How to configure web pages for accented characters?

I have a simple form to insert products in a mysql table but it's not working with accented words.  For example: If I post the word "Calcao" it shows up but if I post the correct Portuguese word "Calção", it doesn't show.  Can anyone help me setting the encoding/charsets?  I'm running this on localhost with MAMP and I have tried to set Database charset to utf8_general_ci and utf8_swedish_ci but none seem to work.  I have:   connection.php that connects to database; add.html that shows the form to insert data; add.php who takes action and validate data; view.php where data will apear.   If I post the word "Calcao" it shows up but if I post the correct Portuguese word "Calção", it doesn't show.


Determinant of $A_{n \times n}$ matrix where $a_{ij} = (b_{i} ^{2} - b_{j} ^2)$

Determinant of $A_{n \times n}$ $n≥3$ matrix where $a_{ij} = (b_{i} ^{2} - b_{j} ^2)$ $i,j = 1,2,3,4....n$ for some distinct real numbers $b_{1}, b_{2},b_{3}....b_{n}$. Then what is det$|A|$ $?$  Clearly, this is a skew symmetric matrix, so determinant is $0$ when $n$ is odd. But I've no idea about its determinant when $n$ is even.   Any hint or idea to solve this problem$?$


Font size issues with Emacs in linum-mode

I am using Emacs 23. linum-mode works well if using with default settings.  But if I increase the font size, the numbers cannot be displayed. It seems the the frame to display the line numbers is not increased as the font size of the line number increases.  Anyone know how this can be fixed?


locale not found/setting locale failed - what should I do?

I've installed Debian 7 i386 on my VPS (OpenVZ). Everything works fine, except locales - any attempt to install anything shows:  [...] perl: warning: Setting locale failed. perl: warning: Please check that your locale settings:     LANGUAGE = (unset),     LC_ALL = (unset),     LANG = "pl_PL.UTF-8"     are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory [...]   What I've tried:   Generating locales myself - update-locale LC_ALL="pl_PL.UTF-8" - shows:  apt-get install --reinstall locales  The same with dpkg-reconfigure locales + setting pl_PL.UTF-8, pl_PL.ISO-8859-2 or even en_US:  export LC_ALL=pl_PL.UTF-8 (even on root):  -bash: warning: setlocale: LC_ALL: cannot change locale (pl_PL.UTF-8)    Here is what shows locale:  root:~# locale locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory LANG=pl_PL.UTF-8 LANGUAGE= LC_CTYPE="pl_PL.UTF-8" LC_NUMERIC="pl_PL.UTF-8" LC_TIME="pl_PL.UTF-8" LC_COLLATE="pl_PL.UTF-8" LC_MONETARY="pl_PL.UTF-8" LC_MESSAGES="pl_PL.UTF-8" LC_PAPER="pl_PL.UTF-8" LC_NAME="pl_PL.UTF-8" LC_ADDRESS="pl_PL.UTF-8" LC_TELEPHONE="pl_PL.UTF-8" LC_MEASUREMENT="pl_PL.UTF-8" LC_IDENTIFICATION="pl_PL.UTF-8" LC_ALL=   Nothing interesting found in /var/log. Even changing repo to official + purge and manual installation locales doesn't solve my problem, which manifests itself on each fresh installation of Debian 7.


How can I unite two LAN connections on one network?

The small flat in which I live is designed for two students. I manage to pay the entirety of the rent myself, so I'm living by myself, but I have 2 LAN outlets in the flat. I wish to configure a local network of my own with several computers and a router. How can I connect the two outlets to one network? What hardware is required?


I'm trying to find a video - Who should I ask?

The Stack Exchange network seems like the best way to get good answers fast, but I don't if and what SE forum I should use to ask my question:  I'm looking for somewhere, anywhere, that would let me view and or purchase the full taping of the September 20th, 1973 tennis match between Billy Jean King and Bobby Riggs, also known as "The Battle of the Sexes". I just need evidence that it exists somewhere so I can go about trying to obtain it. Any help at all would be greatly appreciated.


In the case of languages with a C-like syntax, we declare the main() method to return an int or float value (or void).  Is it possible to declare a non-void return type from main() in Java?  If not, then why not?  Does this mean that a Java program doesn't return any value to the OS?


Is Creating a Bootable USB Drive Permanent?

More specifically, I want to know if when I put the Ubuntu OS on my flash drive if it is permanent or not. As in,can I delete the Ubuntu installation files after I install it on my computer and use it as a regular USB again? I just want to install Ubuntu on a unformatted hard drive and then be able to use my USB like normal again.  Sorry, I know I must sound very redundant. Thank you for the help.


What is the speed of light escaping a neutron star?

If the escape velocity of a neutron star is just less than that of light, will light come out very slowly from the star?


I have heard along the grapevine that at some point, Dragonborn can get wings and/or a tail. But I haven't been able to find anything on it. I have looked through the Player's Handbook, and I couldn't find anything in there about it.  So do Dragonborn get tails or wings at any point? I know they don't start with any, but as I said previously, I heard they could. Does it depend on the ancestry as well? (I.e. Blue Dragonborn only get tails, Black only get wings etc).  This is the inspiration for this question. I'm unsure of where it came from, it may just be fan art, but I have seen similar images (perhaps by the same artist) that led me to believe that this may be canon.


rm -rf .* will only not end horribly because rm refuses to delete . and ...  How do I exclude these special directories from a glob pattern?  This is not solved by dotglob since I want to match only files beginning with a dot not all files.


Random questions in the "newest" tab come with background colour

I have noticed recently, that random questions appear with light orange (debatable) background colour like :        I could not make out why is this happening.  Any significance of this?  For assistance :  My favourite tags are :


Possible to do silent/unattended install of XFCE/KDE on debian?

The way I'm installing the DEs:  XFCE:  apt install -y xfce4   KDE:  apt install aptitude tasksel aptitude install ~t^desktop$ ~t^kde-desktop$   Both seem to prompt for a selection for the language/keyboard halfway through. Is there an option to make it auto-select default and proceed?


taught more than 100 hours or taught for more than 100 hours

When using the verb "run", I realized that we can say "I ran 2 hours last night." without including the preposition "for". I wonder if we can do the same thing to "teach"?   I have taught more than 1000 hours in total.  or do we have to use "for"?  I have taught for more than 1000 hours in total.


Can I make ctrl + right/left go to the next/last capital letter rather than the next/last word respectively, in Visual studio?

I often use these shortcuts in Eclipse, and the shortcut will bring you to the next capital letter in the word- for example:  variableName|   pressing ctrl + left arrow will make the cursor go like this:  variable|Name   However, this is not how it works in Visual Studio. It goes to the next word, rather than the next capital letter. I don't know how to search for this problem on Google.  I'm using Visual Studio Community 2017.


How can I switch an application to a different playback device on Windows 10

Googling for solutions to this problem seems to lead to third party solutions like , sometimes with scripting like .  I'm no stranger to either, but It seems crazy to me that there isn't a better solution.  I'm on Windows 10.  I use HDMI audio to my monitor from my AMD video card, and I use a set of headphones plugged into the back of my motherboard.  I use both often, but right now I need to  switch the default playback device to switch between them (sometimes, for reasons I don't yet know how to replicate, I even need to fully disable the device currently making sounds.    This is what I see in the volume mixer after starting my computer up with AMD HDMI as the default, and opening Chrome to watch a video:    When I switch to the Speakers device    I see that it is not assigned any applications, and I see no way to reassign applications:    I can usually hammer all of the applications over to the Speakers device by switching the default playback device, and usually vice versa.  But that sometimes that only switches some applications, and sometimes it doesn't do anything.  But that's besides the point...  How can I assign an application to a specific audio playback device?  The Volume Mixer looks like the right place, but it doesn't seem to do it unless I'm missing something.


How to install PHP from source with latest cURL package on Linux?

I simply have to use the latest cURL version (7.21.3) with PHP on my webserver. (Has to do with specific bug fixes)  It is not available by default on most current Linux variant repositories. (Natty Narwhal by Ubuntu is the only one and it's still in beta stages) - so I cannot simply run "aptitude install php5-curl" or similar to get it (the very latest version of cURL) installed.  How would one go about installing the very latest PHP + cURL packages?  Is it as simple as changing the to-download file for cURL in a repository somewhere? (ie. changing a text file's entry somewhere from  to  or something..?)  Basically I need the very latest cURL library running with PHP on Linux. How would you personally go about doing that?


I have an issue with the Lightning Datatable which dispatches an event when a column header is clicked. That event holds among other things the sorting order, 'asc' or 'desc'.  The problem is that the given order is always 'asc'. Despite the docs specifying otherwise :      Clicking a column header sorts rows by ascending order unless the defaultSortDirection is changed, and clicking it subsequently reverses the order   Here is a playground link that shows the error (click on a column to sort and observe the given sorting order in the console) :     Am I missing a parameter or something ?  Thank you in advance !


Smart Network Data Service reports spam from my IP. Nothing in my logs

I am facing a very strange situation. Microsoft's Smart Network Data Service is reporting that my IP is attempting to send hundreds of thousands of spams to Microsoft accounts every day.    But, checking my server's logs I have found no indications of that kind of sending volume.  My Qmail queue is 0  None of the recipient email address mentioned in the SNDS report is found in my logs.  No malicious or suspicious script is running on my server  For example, in the sample spam message that I've got from SNDS it mentions "X-PHP-Originating-Script: 1249:phoned.php". No such file is present on my server!!!  So how is this possible?


How to see a user's profile in the Stack Exchange Android application?

In the Android application of Stack Exchange, I can't see my profile, nor other user's profiles. Is there any way to see any user's profile in the Android application?


Computing the limit with a radical: $ \lim_{x\to\infty}\left(\sqrt{x^2+4x}-x\right) $

I've been struggling with the below problem (I'm a Calc I student and don't know how to approach this using the skills I've developed so far):  $ \lim _{x\to \infty }\left(\sqrt{x^2+4x}-x\right) $  I've tried rewriting using the conjugate:  $ \dfrac{4x}{\sqrt{x^2+4x}+x} $  But I'm not sure how to proceed. Writing the part of the denominator that is under the radical as a power of $ \frac{1}{2} $ is the only thing I can think of, but what emerges is really messy algebraically and I still don't know how to find the limit from there.


Simple question but I cant find anyway online to delete an original output in the way for a new one

print ('hello, welcome to our bar') age = int(input("What is your age"))  if age < 21:     print ('*kicks your ass out of bar*') else:     print("come on in")   I am able to run the code and have it ask for a number, once you enter the number under the number the desired output comes out. What is want is for instead of the output to look like hello, welcome to our bar What is your age25 come on in  I want it to just look like come on in  very new so sorry if this is super simple I have been searching for someone who has previously asked this but none of the code I'm finding works


How can we remove the launcher that come with Unity on this new Ubuntu version ?


Consider the following example sentence: "If in addition he is happy, we are done." What is the correct place for the comma(s) for the phrase "If in addition"? I see two possiblities:  If, in addition, he... If in addition, he....  Are both acceptable or just the first one?


If a Hero makes a Speed/Sanity/other non-Might attack, when does the Traitor reveal that the target lacks that trait and can't be attacked that way?

This came up in a game involving Haunt 23, Tentacled Horror. (Spoilers will be kept to a minimum.) There are multiple different types of monsters in that Haunt: some of them have a Sanity trait, and others don't. One of the Heroes had the Ring, which let him attack with Sanity instead of Might. He attacked a monster that had a Might trait, but no Sanity trait, using the Ring. At the time, I told him that the monster had no Sanity trait and that he'd need to try a different type of attack, and he ended up doing a Might attack using the Sacrificial Dagger instead.  Was this the right thing to do, or should the initial attack have failed entirely? Or should we have explained which traits the monster does and doesn't have the instant the monster went on the map? The rules just say "you can't use a trait to attack against a monster that doesn't have that trait," but it's unclear on how to handle the attempt. This is particularly vexing, because all monsters have hidden traits and this is going to come up again.  (I looked at the , and it turns out that the specific Haunt I was looking at no longer has that problem, but I'm sure this question will still apply to other monsters.)


How to install League of Legends in Ubuntu

I'm using Ubuntu 14.04 and PlayOnLinux 4.2.2. I managed to get League of Legends almost running perfectly, there are only two problems. The first is that the shop to buy things with IP/RP is just a black screen. Here is a screenshot:    The second problem is that in the game, during the match, some menus are messed up, as if they were in a different resolution from the game's current resolution. For example, the item shop opens a normal window, but this window's contents are all over the screen. Here is a screenshoot:    All the rest is working fine, I even get high FPS. I installed LoL via PlayOnLinux and then I applied TuxLoL patch. I have an Optimus Notebook, Dell Inspiron 14R 5421, it has an Intel integrated video card and Nvidia GeForce 730M dedicated card, which are properly handled by Bumblebee.  How do I fix these two problems? Could somebody help me, please?


I have two questions:  1. Which one is determined first: (i) Random variable's values, (ii) the random experiment?  For instance  link says the following:     Suppose a variable X can take the values 1, 2, 3, or 4.       The probabilities associated with each outcome are described by the following table:   Outcome     1   2   3   4 Probability 0.1 0.3 0.4 0.2      The probability that X is equal to 2 or 3 is the sum of the two probabilities: P(X = 2 or X = 3) = P(X = 2) + P(X = 3) = 0.3 + 0.4 = 0.7. Similarly, the probability that X is greater than 1 is equal to 1 - P(X = 1) = 1 - 0.1 = 0.9, by the complement rule.   Which means, the values of Random Variables are decided first which is very unusual.  2. Can a Random Variable take random values?  For instance, can we roll a die and a random variable associated with it take on,  X = {99, 0, 100, 1, -35, 2.4} ?


Indentation inside algorithmic environment

Consider the following snippet:  \documentclass{article} \usepackage[textwidth=8.5cm]{geometry}  \usepackage{amsmath}  \usepackage{algorithm} \usepackage{algpseudocode} \usepackage{parskip} \pagenumbering{gobble}    \begin{document}     \hrule     \smallskip     \begin{algorithmic}[1]         \State Initialize $Q$ to hold all pairs $(w_i,w_j)$ s.t. $v_i$ and $v_j$ are T-C         \While {Sequence size is bigger than 1}         \State Find T-C pair $(w_i,w_j)$ s.t. $w_i+w_j$ is minimal         \State Combine $v_i$ and $v_j$ to a new node $v_k$, and form new sequence (if $v_i$ and $v_j$ are non-adjacent, let $v_k$ take the left position in the resultant sequence)         \State Update $Q$ accordingly         \EndWhile     \end{algorithmic}     \smallskip     \hrule \end{document}   Which produces the following:    How can I indent the lines in step 4. to be aligned with the other lines in the While loop? I tried breaking them with // or adding \hspace{} but this didn't work...


Blade of the Ruined King Vs. The Bloodthirster

Effects:  +25 attack damage +15% life steal +40% attack speed Passive  Unique: Your attacks deal 5% of the target's current health in physical damage (60 max vs minions and monsters). Active   Unique: Drains target champion, dealing 15% of the champion's maximum Health in physical damage and healing you by the same amount. Additionally you steal 30% of their movement speed for 4 seconds - 60 second cooldown. (500 range)  Cost: 3200g VS.   Effects:  +70 attack damage +12% life steal Passive: Gain +1 attack damage and +0.2% life steal per kill (maximum +30 attack damage and +6% life steal). Half of the bonuses are lost upon death.  Cost: 3200g What is better for what situations, and when should you build BT instead of BotRK and Vice Versa. Which provides more lifesteal, the only variable being the stats of the weapon? I find myself constantly questioning my decision on which weapon to get and would really love some in depth answers. Would be great if any examples given were given from the ADC side of the house.


We have a SFTP Server and a bunch of users. The users share files over the SFTP Server with us (not the best solution, I know).  Every user is chrooted into a different directory to prevent them from cd to a higher directory and seeing the other users (Folders are named after users). another requirement is, that only SCP(/SFTP) is allowed - so no shell. We also want certificates for authentication.  Until now we used scponly to meet all the requirements. But scponly is deprecated now so we can't use it anymore and need an alternative. Some Googling brought SFTP chroot and rssh to daylight but neither seem to meet all specifications.  EDIT: We are using SLES 12


I have a doubt about using 3rd party PCIe SSD or SSD generally with HP DL380p Gen8. Do someone have tested it by any chance with 3rd party PCIe SSD and/or SSD's and/or normal HDD's ?  or by any chance if tested with OCZ 240GB PCI Express RevoDrive 3 X2 SSD ?


Sound difference between musical instruments

I know that the difference between two musical notes is given by the sound frequency, and the difference in volume is given by the amplitude.  What I am wondering is why does the same note sound different on different musical instruments?  What in the wave makes the difference between the sound of a harmonica and the sound of a violin singing the same note?


Proof that $ (\mathbb{Z} \times \mathbb{Z},+) /\langle(2,3)\rangle $ is cyclic.

I need a little help with the second half of the proof that $ (\mathbb{Z}  \times \mathbb{Z},+) / \langle(2,3)\rangle $ is cyclic.  I know isomorphism preserves cyclic structure.I looked up the answer on my textbook from where I got this exercise and their proof is like this:  "The function $f : \mathbb{Z} \rightarrow \mathbb{Z}  \times \mathbb{Z} /\langle(2,3)\rangle$ with $f(x) = \widehat{(x,x)}$ is an isomorphism of groups because :   $(x,x)$ is not in $\langle(2,3)\rangle$ for every $x \neq 0$. $(a,b) =(b-a)(2,3)+(3a-2b)(1,1)$ for a,b in $\mathbb{Z}$ .   I think in the first part they try to show that the function is injective but I don't understand the second part,can someone explain it to me?  Thanks alot !


How to change permissions on a usb stick?

I have two usb sticks,both are recognized automatically but when I try to write or copy files to either it comes up with error saying I do not have permission to copy to this destination folder.I have changed the permissions in properties but it will not let me to change the permissions for the actual usb stick. What can I do?  EDIT: USB stick info from comments:  Solaris Disk /dev/sdb: 2065 MB, 2065694720 64 heads, 8 sectors/track, 7880 cylinders, total 4034560 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc3072e18 Device Boot Start End Blocks Id System /dev/sdb1 * 32 4034559 2017264 6


Can we actually prove with 100% certainty that there are more than 3 dimensions plus time $(t,x,y,z)$?

Can we actually prove with 100% accuracy that there are more than 3 dimensions plus time?  In the news there are always articles like "there are probably 7, 11 or more dimensions", "time is actually not a 4th dimension" etc.  My question is:   Could we be 100% sure that there are more than 3 dimensions and what field of physics except some theoretical or hypothetical branches of physics and mathematics take that in count that there are more than 3 dimensions plus time?  I know the example of a 2D "creature" being unable to see 3D creature (maybe only the interference when the 3d object collide with the 2d world. But I can argue that there are no 2d or 1d beings like in that episode of Star Trek. So, this proof is only an illusion and all we see is 3d and not 1d or 2d. the light itself is bending in space-time depending how the object looks.   I think that 1d or 2d objects can not exist in 3d world at all and it's just an illusion we created, the same way as we speak about 4th,7th etc. dimensions and probably it's all 3d (or chose the name as you wish).  Is this guy correct that 3 dimensions and time is all we need?  Could it be that we are creating other dimensions only because we don't understand our Universe good enough?  I mean, don't get me wrong, but the whole 7,11,21,1000-dimensions seems to me like a marketing, something too provincial (as Feynman would say), something like... religion ;D.


Preventing \MakeUppercase from affecting mathematics

Is there a way to prevent \MakeUppercase from affecting in-text equations? In this example, abc should change to ABC, but n should be left as it is.   \documentclass{article} \begin{document} \MakeUppercase{abc $n$} \end{document}   The following works for individual characters, but I would like something more general.  \documentclass{article} \begin{document} \newcount\mycount \mycount\mathcode`n \MakeUppercase{abc $\mathchar\mycount$} \end{document}


Difference between two Why...? questions

What is the difference between these two questions:        Why Sweden makes the best music?   Why does Sweden make the best music?      I suppose there is no difference and one of these is just incorrect. Am I right?


If the Sums of all $k$-th Powers are Equal then the Terms are Equal

Consider the following problem:     Let $a_1, \ldots, a_n$ and $b_1, \ldots, b_n$ be real numbers such that   $$a_1^k+\cdots a_n^k= b_1^k+ \cdots+b_n^k$$   for all $1\leq k\leq n$.   Then there is a bijection $\varphi:\{1, 2, \ldots, n\}\to \{1, 2, \ldots, n\}$ such that $a_i=b_{\varphi(i)}$ for all $i$.   This can be proved using , which gives that the polynomials $p(x)=(x-a_1)\cdots(x-a_n)$ and $q(x)=(x-b_1)\cdots(x-b_n)$ are identical.  My question is, can this be said about countable sequences. More precisely, is the following true?     Let $a_1, a_2, a_3, \ldots$ and $b_1, b_2, b_3,\ldots$ be real numbers such that   $$a_1^k+a_2^k+a_3^k+\cdots = b_1^k+ b_2^k+b_3^k+ \cdots$$   are equal for all $k\geq 1$ (Here we insist that both sums are convergent for each $k$).   Then there is a bijection $\varphi:\mathbb N \to \mathbb N$ such that $a_i=b_{\varphi(i)}$ for all $i$.


Napoli go missing against Juventus as Higuaín seals a victory for 'Maxism'   This sentence is the title of . I really don't understand why " go missing" is used instead of " goes missing".


Change size of StringProperty Text Input

Is there a way to increase the vertical height of a ? My goal is to have a multi line text entry field.    I have applied a  which works on operator buttons but doesn't seem to work on a StringProperty      sub = col.row()     sub.scale_y = 3.0     sub.operator("render.render")     sub.prop(scene.video_info,"video_description")   Edit for clarification  My objective is to have a text entry field that can accept an arbitrary amount of user input including multiple lines. I would want it to look something like this:    I know that the Enter key causes the input to be finished. I had made the assumption that could be disabled. If not then this question may be futile in the first place.  The "why" is that I have created an add-on to allow uploading rendered videos to Youtube from within Blender. This would be the description field for a video.


How to send private messages or locate a specific user?

I'm a 17-year-old girl living in Mexico and dreaming of studying at a university in Romania. I speak Spanish and English and am trying my best to learn Romanian, and I can hardly find anyone to whom I can speak in Romanian. My only Romanian e-friend who's actually willing to help won't Skype with me because he lives with his family and the time difference means he'd wake them if we were to Skype at a decent time for me.   Now that you know this, you can imagine my excitement when I randomly found an active user with a totally Romanian name, Bogdan Alexandru, and even more so when I clicked his profile and found that he is indeed from București. But he has no contact links on his profile. Is there any way I can contact him and offer to trade services (like an I'll-help-you-with-Spanish-if-you-help-me-with-Romanian thing)? Or will I just have to put something on my profile, answer one of his questions and hope he looks at my page?


What exactly implies the need of quantum mechanics for self-adjoint and not only symmetric operators?

We know that quantum mechanics requires self-adjoint operators, not only symmetric. Can we say that this follows ONLY from the two following axioms of quantum mechanics, namely that    each observable $a$ corresponds to a linear operator $A$    and    an expectation value of a measurement of $a$ must be real   ?  I thought these two imply only the need for a Hermitian (i.e. symmetric) operators (because a linear Hermitian operator has real eigenvalues)  and that the need for self-adjointness was somehow connected to an additional requirement such as unitarity of the time-evolution operator. What is the missing piece?   (I know how the two terms are defined, e.g. .)


Another question about how to learn algebraic geometry...

I've been trying to learn some algebraic geometry (level of generality: working over an algebraically closed ground field but not afraid of using the language of sheaves and cohomology etc.)  The problem I'm having with it is that most of the references I'm using (Milne's notes on AG, Perrin's Algebraic Geometry, Mumford's Red Book etc.) just seem like endless streams of technical results and whilst I can appreciate most of the concrete examples ("oh look - that's a singularity"...), I'm not really sure what I'm supposed to be doing. On the other hand, books like Reid's Undergraduate AG makes me feel like I'm not sure what the definitions are (if that makes sense to someone!).  At the minute my approach is to check everything line by line (if I can!) and try to build up a picture of how the technicalities fit together into a bigger picture. I've also tried to do the exercises in Chapter 1 of Hartshorne but a lot of them seem too difficult for me at the moment (there feels a big gap between the technicalities of the chapters in the books and the concrete nature of the examples).  Does anyone have some magical book recommendation that I've missed or some other approach that helped them learn the subject?  Many thanks!


What are the chances of a paper being accepted after

I got minor revision in the first round of review. The main concern of the reviewer was to add the details in methods section and some amendments in the text. I re-submitted the paper after incorporating these changes in the manuscript (I work in Biology field). But the status of the paper is showing  "under review" again. Does it mean the manuscript will go through peer review again? what are the chances of the paper being accepted? Please help..


I would like to convert   the hex value   a = 0x32    to a string d = 32  Bascially I have a  numpy array   msg = np.array[2, 50]   I need to convert both values to hex --- [0x02 , 0x32] then print the hex values as strings on GUI as 2, 32


Wireless problems (connected but no internet)

I've checked other solutions to similar sounding problems but to no avail. I installed Ubuntu 14.04.3 LTS last night, experienced no problems with wireless, today, it was fine in the morning, suddenly, no internet. The wireless was still connected to my home network but  ping www.google.com   gave unknown host. If I reboot the laptop, I get an internet connection for a bit and then it dies again.   On a perhaps unrelated note, I booted up the laptop, did some local stuff, put it to sleep, woke it again later and the internet was still fine. As soon as I opened a browser to do some work it suddenly stopped working again. I just don't understand why it connects, works, and then suddenly drops. Any ideas?


I am traveling from India to Prague with a Schengen visa. On my way back, I have a long transit (34 hours) at London. I picked this as I got the best rates. Can I step out of the airport & take in a couple of sites without a UK visa? appreciate your help!


import java.util.Scanner;  public class StudySession { public static void main(String[] args) {     Scanner in = new Scanner(System.in);      String inData;     int age;     System.out.println("Enter your age");     while(true) {     inData = in.nextLine();     if(inData == "STOP") {         System.out.println("Terminated");         break;     }     age = Integer.parseInt(inData);        if(age < 5) {         System.out.println("Under 5's rate.");     }     if(age >= 60) {         System.out.println("Senior citizen rate.");     }      if(age <= 17) {         System.out.println("Child rate.");     }     if(age > 17 && age < 65) {         System.out.println("Adult rate.");     }     System.out.println("Enjoy the show!"); //This prints no matter what.     }  } }   I want the program to stop when the user types "STOP". Why is it not working? You don't have to give me a straight up answer. A clue will do. Perhaps it's something to do with the order of my statements?


Let $A$ be an $m\times n$ matrix with $\text{rank}(A) = 1$. Prove that for some column $u$ in $\mathbb{R}^m$ and row $v$ in $\mathbb{R}^n$, $A = uv$.

Let $A$ be an $m \times n$ matrix with $\text{rank}(A) = 1$. Prove that for some nonzero column vector $u$ in $\mathbb{R}^m$ and a nonzero row vector $v$ in $\mathbb{R}^n$, the matrix $A$ can be written in terms of the outer product  \begin{equation} A = uv. \end{equation}  I do not know where to start, can someone please guide me in the right direction?


Encountering with a pass by reference in Java. How can I do the same thing?

I know Java is only pass by value and not by reference. But I faced this while programming for Android:  int originalPos[] = new int[2]; view.getLocationOnScreen(originalPos); int m = originalPos[0];   Going to the method declaration, I find this:  public void getLocationOnScreen(int[] outLocation) {     throw new RuntimeException("Stub!"); }   I didn't declare this method. I could have done something like this to be able to pull off a fake pass by reference (which is really not a pass by reference and would only work for one variable) in Java:  int locationOnscreen;  public void getLocationOnScreen() {     locationOnscreen = 10; }   but the getLocationOnScreen(int[]) is declared in the Android SDK.  The view is an object of type View in the Android SDK. Any idea on how I can implement something like this?


Expected value of the number of flips until the first head

Suppose we flip a coin until we see a head. What is the expected value of the number of flips we will take?  I am pretty new to expected value, so I tried to evaluate it by multiplying the probability of each scenario with the number of flips it took to get there (like taking the arithmetic mean). This didn't work though, because of the infinite possibilities. I'm really confused, and if someone were to provide an answer, I would really appreciate it if they could go into detail.


How do you find out the "sweet spot" of a lens?

I've tried googling this, but have never found a satisfactory answer.  I've heard the term "sweet spot" thrown around by some photographers to mean the f-stop of a lens which results in the highest sharpness that lens can achieve.  A few questions on this:   General photographic knowledge states that the higher the f-stop (the smaller the aperture), the largest depth of field you will achieve. This seems to "suggest" the higher the f-stop, the sharper your image will be (all other factor being equal of course). Does the idea of a "sweet spot" trump this rule? (so, theoretically a f11 could be sharper than f22) Is the "sweet spot" an optical algorithm that can be applied to any lens, or is it to do with the particularities of the manufacturing of some lens? Finally, how can I determine the "sweet spot" of my prime lenses?   Note: I know other things come into consideration in sharpness, like ISO, light, glass (lens) etc etc, but please ignore these and assume these are equal for every different lens.  For context, I'm mainly trying to achieve ultimate sharpness in architectural (indoor and outdoor) photography, and urbanscape, where usually I tend to shy away from small depth of field.


Show that $\lim_{x\to a^{+}} g(x) =g(a)$

Let $f:\mathbb{R}\rightarrow \mathbb{R}$ be a bounded function and suppose that $g(x)=\sup_{t>x}f(t)$. Show that $\lim_{x\to a^{+}}g(x) = g(a)$ for all real $a$.   I have a hard time with these kind of proofs because in high school, I would simply replace $x$ by $a$ in $g(x)$ to get that $g(x) \rightarrow g(a)$. Obviously, Real Analysis requires a more formal proof.  I can always apply the definition of a limit of a function :  Given $\varepsilon>0$, there exists $\delta>0$ such that if $x\in A$ and $0<|x-c|<\delta$, then $|f(x)-L| < \varepsilon$.  In particular, we have that if  $$ |x-c| = |x-a^{+}|<\delta$$  then  $$|g(x)-g(a)| < \varepsilon$$  How can I find a relation between $f$ and $g$, the sup of $f(t)$ and between $x$ and $a^{+}$?


Function that takes a list and returns a list with only unique elements from the original?

I am working my way through the Think Python Textbook, and one of the problems it gives is to make a function that takes a list and returns a list with only unique elements from the original. What I have so far is this:  def remove_duplicates(l):     index = 0     new_l = []     dup_l = []     while index < len(l):         if l[index] in l[index+1:] or l[index] in new_l:             dup_l += [l[index]]             index = index + 1         elif l[index] in dup_l:             index = index + 1         else:             new_l += [l[index]]     return new_l   I feel like there must be a more succinct, pythonic way to write this function. Can somebody help this beginner programmer?


Does "==" only apply to certain data types?

In this program below:  public class medianTemp { public static void main(String[] args){     int length = args.length;     int[] n = new int[length];     n[0] = Integer.parseInt(args[0]);       System.out.print(n[0] + " ");      for (int i = 1; i < length; i++ ){         String c = args[i];         if (c.equals(".")){             n[i] = n[i-1] + 0;             System.out.print(n[i] + " ");             }         if (c.equals("+")){             n[i] = n[i-1] + 1;             System.out.print(n[i] + " ");             }         if (c.equals("-")){             n[i] = n[i-1] - 1;             System.out.print(n[i] + " ");             }   Inside the for loop and inside the if statements. If I use for example args[i] == "." (instead of converting args[i] to string), the code above doesn't work and only the initial integer is displayed. Can someone please tell me why this happens?


My root account is corrupt or something every time I log into it I just get a blank desktop. I can move my cursor and right click and I get a few options but that's it. I CANNOT open a terminal from this account. I can however use my guest account but it is very limited. I can't save anything and I cant use sudo. Which means that I can't create a new user account from the guest account. The only boot device I have is the flash drive that I used to install Ubuntu with in the first place. I've only been using this operating system for about a month so I'm not too familiar with all the bells and whistles. Is there anything I can do to fix this?


Lightning Community Does Not Support pubsub for Lightning Web Components?

Has anyone successfully used the pubsub module from lwc-recipes to enable inter-component communication in a Lightning Community?  The registerListener function in the pubsub module throws an error because the pageRef property is undefined.  Or is pubsub designed for Lightning Experience only?


How to transform a list to a 2D list like this [[1, 2, 3][4, 5, 6][7, 8, 9]]

i have a added data from a csv file into a list. But now is the list build like this: [1, 2, 3, 4, 5, 6, 7, 8, 9] How to transform a list in a 2D list like this: [[1, 2, 3][4, 5, 6][7, 8, 9]] lcsv=[] newldata=[]  for column     newldata.append(     for row in lcsv:         newldata.append(lcsv[1*row][0])         newldata.append(lcsv[1*row][1])         newldata.append(lcsv[1*row][2])     )  what's wrong?


Can we have a black hole without a singularity?

Assuming we have a sufficiently small and massive object such that it's escape velocity is greater than the speed of light, isn't this a black hole? It has an event horizon that light cannot escape, time freezes at this event horizon, etc. However this object is not a singularity.  If a large star's mass were compressed to the size of, say, a proton, it would certainly have these properties but it would still not be a singularity as a proton does have volume.  The reason "physics breaks down" at singularities is because we cannot divide by zero, but as long as the proton-sized object has volume, physics won't "break down", yet we still have an event horizon and an object that is invisible (but not undetectable) from the outside.  I have read the answers to  related question. I'm not sure if they don't address my specific question or if I don't understand the answers.


In LASSO, does it make sense to choose lambda based on the mean error associated with different lambda values, over multiple cross-validations?

I am running a LASSO regression, but am put off by the different values of lambda each time I run the cross-validation. Does it make sense to run a cross validation multiple times, take the mean error associated with each lambda value, and then choose lambda.1se (i.e., the largest lambda resulting in error within 1 se of the minimum) from the distribution of lambdas and mean errors?  library(glmnet) set.seed(3)  IV1 <- data.frame(IV1 = rnorm(100)) IV2 <- data.frame(IV2 = rnorm(100)) IV3 <- data.frame(IV3 = rnorm(100)) IV4 <- data.frame(IV4 = rnorm(100)) IV5 <- data.frame(IV5 = rnorm(100)) DV <- data.frame(DV = rnorm(100))  data <- data.frame(IV1,IV2,IV3,IV4,IV5,DV) x <- model.matrix(DV~.-IV5 , data)[ , -1] y <- data$DV   lambdas <- NULL n.fits <- 100 for (i in 1:n.fits) {     {   fit <- cv.glmnet(x,y)   errors = data.frame(fit$lambda,fit$cvm)   lambdas <- rbind(lambdas,errors)   r2[i]<-max(1-fit$cvm/var(y)) } # take mean cvm for each lambda lambdas <- aggregate(lambdas[, 2], list(lambdas$fit.lambda), mean) lambdas<-as.data.frame(lambdas)  # find subset with mse within 1 se of mean onese<-std.error(lambdas[2]) min<-min(lambdas[2]) low<-min-onese high<-min+onese  lambdas<-subset(lambdas, x>low) lambdas<-subset(lambdas, x<high)  #choose highest lambda among those  bestindex = which(lambdas[1]==max(lambdas[1])) bestlambda = lambdas[bestindex,1]   Edit: My question is unique because I am asking about how to implement the one standard error rule after iterating the cross validation.  Edit 2: It's possible my question isn't clear. I am being linked to a previous question which is different. That one talks about running cross validation once and choosing the best lambda from that process. I would like to run cross validation multiple times, averaging over the different results, and choosing the best lambda based off of that. I would like to know if my code is an acceptable way of doing that.


Find the relationship between the sides of a triangle and the diameter of the circumscribed circle.   I tried to solve this question. But, I didn't get any solution


I have downloaded and installed JDK 9 with NetBeans. NetBeans runs fine and I build test application that also runs fine from IDE. But if I run java command in terminal I have error   'java' can not be found in the following package: ...   So, where is my java? Should I download JRE separately?  Command  sudo update-alternatives --config java   gives  update-alternatives: error: no alternatives for java


Visa needed for Indian citizen to visit Zurich during layover?

I am from India and travelling to Germany on a Schengen visa. On my way back to Mumbai from Munich, I have a layover of 9 hrs in Zurich. Can I travel in Zurich on the same documents or I need anything more?


How to pass field values to apex class by command button?

I need to pass id field value to apex class to delete that row by using command button.  Class:  public class search_delete { public string id {get;set;} public list<account> acc{get;set;} public search_delete() {     acc = new list<account>();             acc = [SELECT id,name,phone,industry from account];  } public void delete_record() {  acc = [SELECT name,phone,industry from account where id = :id];  delete acc; } }   VP:  <apex:page controller="search_delete" >  <apex:form >      <apex:pageBlock >          <apex:pageBlockTable value="{!acc}" var="a">          <apex:column value="{!a.Name}"/>          <apex:column value="{!a.Phone}"/>          <apex:column value="{!a.Industry}"/>                   <apex:column >              <apex:commandButton value="Delete" Action="{!delete_record}">                  <apex:param name="accId" value="{!a.id}"/>              </apex:commandButton>          </apex:column>          </apex:pageBlockTable>      </apex:pageBlock>       </apex:form>  </apex:page>   Now i need to pass id value to apex class from Vp page by the click of delete button.


I'm working on a website that would have a mass of uploaded images, each with a max of 2mb but adding up, in total, to much more than my VPS hosting (which has a max of 100gb used up by a lot of other similar projects) allows. I can not pay for a bigger plan and the website itself, as a .org, will likely not have advertising on it.  Everything including the PHP, CSS, JavaScript and website logos and artwork can be stored locally. It's just the images that cannot.  What I'm looking for is something that is free, doesn't track people, is reliable and easy to work with using PHP/JS and HTML. I don't want something that would require all the people using my website to also be logged into the image host.  Cheers, MyUser


How to push the text to the right side of a flex  element

As you can see in the snippet below, I have a 2x2 grid made in flex. The problem I have with it is that the text inside the top right and bottom right
 elements are on the left side of the
 and I would prefer if I could push them to the right side. I've tried fiddling with justify-content: flex-end; but it doesn't seem to do anything in my case.    .stats-container {     display: flex;     flex-wrap: wrap; } .stats-container > p {     flex-basis: 50%; }

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