Read this short story 10-20 years ago, don't know where. Premise is that this fighter pilot dies, and the Devil offers to dogfight him for his soul (I think his soul was going to be consigned to purgatory otherwise). Fighter pilot agrees and does some cleverness involved in choosing the planes (e.g.  It's a P-39 model "H" which was somehow superior to the regular series.  Don't remember the exact plane, but pretty sure it was WWII-era, allied side, for the pilot).  Fighter pilot wins (possibly because of better turning radius?) Having lost the rights to the soul, the Devil ups the bargain -- win again (best 2 of 3?) and he'll release a whole bunch of fighter pilot souls from purgatory.   New rule -- the Devil gets to choose the models of planes in the next fight.  Fighter pilot agrees, and still wins (bad type of plane but still good at one thing?). Having released everyone from purgatory, fighter pilot gets offer to reincarnate (him and all his friends) and go fighting for "good" in some far off space force.

A while ago a friend told me the plot of a book (or book series, he isn't sure) that he couldn't remember the name of, and I want to find it.  Here's what he told me:   Every person in existence is in hell: Mozart, Hitler, Ghandi, everyone. No one knows why for sure. Hell is a lot like normal modern life, but everything is slightly worse. There is an eye in the sky and everyone thinks it is watching them. Dante is in hell and he's some kind of programmer/IT guy, and he thinks the reason he's here is something offensive in the divine comedy. He keeps trying to rewrite it to fix the problem, but his computer always crashes and erases the file before he can finish. People can't die here; when they do they are taken to some sort of incredibly creepy guy to get stitched back together.  The only exception to this is Hemingway, supposedly because he spent his whole life preparing to die, so now he can't even temporarily discorporate.    I have never run into anyone who recognizes this - I'm told Riverworld is sort of similar but not really? It'd be awesome if this rings a bell for someone, thanks.


:  MY eggs were in the refrigerator and we were out of town for 3 days.When we returned I noticed that the fridge was not as cold as I thought it should be.  We placed a thermometer in it and the readings fluctuated between 40 and 60 degrees all day.  These were refrigerated eggs purchased from a grocery store They were refrigerated when I got them home They were in 40 – 60 degrees for 3 days Are they safe to eat?

A friend of mine accidentally left a carton of eggs on her counter, unrefrigerated, for three days. The eggs had been previously refrigerated both at the store and at home. Now she's planning to do some more cooking which requires eggs, and is wondering if it's still safe to use them for baking. I believe she is planning on baking cookies with them, so they would be baked at fairly high temperatures for probably at least 10 minutes. Would this be safe, or are eggs left unrefrigerated for that long not safe for consumption?


I have built a custom inputSelect component:   <template>     <div class="slds-select_container">         <select class="slds-select select-input" data-rea={reatag}>             <option value="">None</option>             <template for:each={options} for:item="optionstr">                 <option value={optionstr} key={optionstr}>{optionstr}</option>             </template>                     </select>     </div> </template>   Javascript:  import { LightningElement, api } from 'lwc';  export default class ReaInputSelect extends LightningElement {     @api value;     @api options;     @api reatag;      renderedCallback() {         let curSelect = this.template.querySelector(".select-input");         if(this.value) {             curSelect.value = this.value;         }     }      @api getSelectValue() {         let curSelect = this.template.querySelector(".select-input");         return curSelect.value;     } }   It works okay. But the problem with this one is: when the value passed through @api is changed, it doesn't rerender. The reason is pretty obvious since it only sets the value during renderedCallback() time.   I tried to find a lifecycle hook in this page:  . But it doesn't seem to be a hook for the changing event of @api attributes.   How should I resolve this?

Is there a way in LWC to declare an attribute value change handler like there was in Aura?  My use case is that I have a pager component which has 2 @api properties.  When either of the @api values are changed, i'd like to reset the state of the component.  import { LightningElement, api, track } from 'lwc';  export default class Pager extends LightningElement {     @api pagerData;  // rows of data being paged     @api pageSize;   // the size of the page      @track currentPage;  // 1s based page number (i.e. 1 is first 'index')      ...      // (other properties that get number of pages, etc.)      ...  }   So when, for example, pageSize is changed by the parent component, then I'd like to reset the currentPage to 1.    To be a little more explicit, the parent component would have something like this in their markup / js  // testpage.html ---------------------------------------- <template>     <c-pager page-data={myQueryResult} page-size=2></c-pager> </template>  // testpage.js ------------------------------------------ import { LightningElement, api, track } from 'lwc';      ...      onSomeEvent(event){        let pagerCmp = this.template.querySelector('c-pager');        pagerCmp.pageSize = 3;        //------------------------        // pagerCmp should handle changes to its own internal state,         //  in this case it should reset its currentPage property to 1        //------------------------     }      ...  }   Basically i'd like to write some code in the pager component to call a setup() function when the value of pageSize is changed, since the change to the @api parameters will warrant a reset in the internal state of the component.  I'm not sure how to do this in LWC.  Any ideas?  Thanks in advance.


Someone was fiddling with my Android (version 5.1.1) phone and somehow managed to change the Settings' color scheme.  I've tried to reset the theme to no avail. I've also noticed some notifications come through with white text (assuming related issue).  (Click image to enlarge)

iOS has a nice option in the accessibility menu that allows you to invert the screen colors. Does Android have anything like this?


I'm trying to use Bash string substitution to combine an array. Desired output: cat,dog,fish  This works, but isn't there a way to do with without piping? #!/bin/bash  words=(cat dog fish)  echo "${words[@]}" | sed 's/ /,/g'  I've been trying this, which doesn't work. echo "${words[@]// /,/}"

My bash script:  #!bin/bash MY_ARRAY=("Some string" "Another string") function join { local IFS="$1"; shift; echo -e "$*"; } join "," ${MY_ARRAY[@]}   I want the output to be: Some string,Another string.  Instead, I get Some,string,Another,string.  What must I change to get the result I want?


let $f(x)=f(x_{0})+f'(x_0)(x-x_0)+\cdots+\frac{f^{(n)}(\xi(x))}{n!}(x-x_{0})^{n}$  I need to prove that $x \mapsto f^{(n)}(\xi(x))$ is continuous if $f\in C^n[x_{0}-\delta,x_{0}+\delta]$ or in other words if $f$ is $n$ times differentiable.  A function is continuous if $\lim_{x\rightarrow x_{0}}f(x)=f(x_0)$. I know that $f$ must be continuous, because it is n times differentiable. However when we reveal $f^{(n)}(\xi(x))$ we get that  $f^{(n)}(\xi(x))=\frac{(f(x)-f(x_{0})-f'(x_0)(x-x_{0})-\frac{f''(x_0)(x-x_{0})^{2}}{2}-\cdots-f^{(n-1)}(x_0)\frac{(x-x_0)^{n-1}}{(n-1)!})n!}{(x-x_{0})^{n}}$  When we take this to the limit we get  $\lim_{x\rightarrow x_{0}}\frac{(f(x)-f(x_{0})-f'(x_0)(x-x_{0})-\frac{f''(x_0)(x-x_{0})^{2}}{2}-\cdots-f^{(n-1)}(x_0)\frac{(x-x_0)^{n-1}}{(n-1)!})n!}{(x-x_{0})^{n}}$ and from there a $\frac{0}{0}$ uncertainty.  This is the extent to which I think I have correctly solved this exercise, but now I (this is how I must solve it) must apply the L'Hospital rule. I am not sure what is the correct way to go about this, but I'll give what I think might be true.  If we differentiate both the numerator and the denominator once we get:  $\lim_{x\rightarrow x_{0}}\frac{(f'(x)-0-f'(x_0)-f''(x_0)(x-x_0)-\cdots-f^{(n-1)}(x_0)\frac{(x-x_0)^{n-2}}{(n-2)!})n!}{n(x-x_0)^{n-1}}$  Assuming this is even correct, I have no idea where to go from here. If at all possible, please provide explanations. Thanks!

Why is this function continuous over $x$? $$f^{n}(\xi(x))=\frac{-(n!\left(-f(x)+f(x_{0})+f(x_0)(x-x_0)+\ldots+\frac{f^{n-1}(x_0)*(x-x0)^{n-1}}{(n-1)!}\right)}{(x-x_0)^n}$$  I tried solving it via the Heine sequence criteria, but to no avail. I need someone help me with the explanation for this, please! Could the answer be, that since the left side of the equation is the final remainder of a Taylor series and a Taylor series converges to a certain function, then that remainder would ideally converge to zero?


I have a player that's a born lycanthrope (weretiger), that was bitten by a known werebear.  one of my other players is planning on casting remove curse on them.  Would the caster know that the spell was unsuccessful, or would it be a "weird feeling", or would it be a "find out at the next full moon" thing?  The reason for the question is that the other players don't know that this character is a born weretiger.  This player is waiting for an exciting moment or something to unveil their weretigerness and would prefer me to not give anything away, however I don't want to possibly change how remove curse works.  If the caster knows it didn't work i can phrase it so they're just confused, until the unveiling of the weretiger, but if they didn't know if it worked then there's nothing to worry about.

Suppose a cleric casts Zone of Truth on a captured enemy. Unbeknownst to them, the enemy is a rakshasa. Zone of Truth says (PHB, p. 289):     You know whether each creature succeeds or fails on its saving throw.   But (MM, p. 257):     The rakshasa is immune to spells of 6th level or lower unless it wishes to be affected.   Assuming the rakshasa doesn't wish to be affected by the Zone of Truth spell, does the caster know this?  More generally, does a caster know when targets are unaffected by a spell they have cast, either because they have made saving throws, or because they are outright immune to the spell or its effects (e.g., casting Ray of Sickness on a shadow demon, which is immune to poison damage and the poisoned condition)?


For a dupe clarification: My question is not a dupe of . Instead, my question is like a follow-up of that question. That one mainly reports the re awarding of badges, and not the number, which has not been fixed till now. I am reporting the number, not the re-awarding.    I  of the double rewarding of badges. That even happened to me. I was rewarded the marshal badge twice again. Looks like that has been , but still there is a bug left.  I just viewed my profile today, and here is what I saw:    6 gold badges?? Well I had only 4 of them till yesterday. So I thought it of course must have been because of the double rewarding. But opening my all badges, it looks as if the badges had been reversed, but not the numbers.   I still have only 4 gold badges:    But the number is wrong. I viewed a few more profiles too, and the same problem was there.

The excavator has been awarded to... many users just some time ago. What a... bug? Certainly it is, too many unavailable posts :D  Seems to affect Marshal and Excavator.        Also looks like it's everywhere. SO's got a similar problem a couple of minutes before.  Moreover, I can has THREE X marshals!!!


I'm getting a NullPointerException when I run my application:  LogCat     java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference at org.example.km.json3.Helper.SwipeListAdapter.getView(SwipeListAdapter.java:52)   The class is given below :  public class SwipeListAdapter extends BaseAdapter {      private Activity activity;     private LayoutInflater layoutInflater;     private List<StockDetails> listStockDetails;       public SwipeListAdapter(Activity activity, List<StockDetails> listStockDetails) {         this.activity = activity;         this.listStockDetails = listStockDetails;      }      @Override     public int getCount(){         return listStockDetails.size();     }     @Override     public Object getItem(int position) {         return listStockDetails.get(position);     }      @Override     public long getItemId(int position) {         return position;     }      @Override     public View getView(int position, View convertView, ViewGroup parent) {          if(layoutInflater == null) {             layoutInflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);         }          if(convertView == null){             layoutInflater.inflate(R.layout.list_row, null);         } //This is the line number : 52              TextView txtStockId = (TextView) convertView.findViewById(R.id.txtStockId);             TextView txtStockTag = (TextView) convertView.findViewById(R.id.txtStockTag);             TextView txtStockExchange = (TextView) convertView.findViewById(R.id.txtStockExchange);             TextView txtStockRate = (TextView) convertView.findViewById(R.id.txtStockRate);             TextView txtStockChange = (TextView) convertView.findViewById(R.id.txtStockChange);             TextView txtStockChangePercent = (TextView) convertView.findViewById(R.id.txtStockChangePercent);             TextView txtStockPreviousClosing = (TextView) convertView.findViewById(R.id.txtStockPreviousClosing);              txtStockId.setText(listStockDetails.get(position).id);             txtStockTag.setText(listStockDetails.get(position).t);             txtStockExchange.setText(listStockDetails.get(position).e);             txtStockRate.setText(listStockDetails.get(position).l);             txtStockChange.setText(listStockDetails.get(position).c);             txtStockChangePercent.setText(listStockDetails.get(position).cp);             txtStockPreviousClosing.setText(listStockDetails.get(position).pcls_fix);          return convertView;     } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Let $G$ and $H$ be abelian groups. Show that the product $G\times H$ is also abelian. I have already proved, that for groups $G$ and $H$ finite groups, then the direct product $G\times H$ is cyclical if and only if $G$ and $H$ are cyclical. However, here I get confused because cyclic groups should be a subset of all abelian groups.

Let $G_1,\dots,G_n$ be groups. Prove that the direct product $G_1\times\cdots\times G_n$ is abelian if, and only if, each of $G_1,\dots,G_n$ is abelian. To prove that the direct product is abelian is straightforward but what I don't understand is the converse.


I've been thinking about the following question:  Is it possible to write $(a,b)$ as a disjoint union of closed intervals?  My first guess was no, but then I figured the question might be hiding something subtle. I tried various things, some which I asked about on this site, and I can't seem to construct such a union. So I decided to go back to my gut feeling and prove that it cannot be done. Attempt: Suppose there is such a union. Then each closed interval contains a rational. Given that the sets are disjoint, any rational specifies a unique interval. Therefore the union must be a countable union, and we can list the closed intervals. Choose some listing $I_1,I_2,\dotsc$ and let: $$(a,b)=\bigcup_{k=1}^{\infty} I_k.$$ Now define $$J_n=(a,b)\setminus \bigcup_{k=1}^n I_k.$$ Specifically, consider that $J_2$ contains a middle interval $(a',b')$ where $a<a'<b'<b$. Construct a sequence where each $u_n$ is arbitrarily chosen in $J_n \displaystyle\bigcap\, (a',b')$. By the Bolzano-Weierstrass theorem, $u_n$ contains a subsequence $v_n$ such that $v_n\to c$. We must have $c \in (a,b)$ so $J_{\infty}\neq \varnothing$ which is a contradiction. Put differently, no matter how the closed intervals are chosen, we can find a sequence in $(a,b)$ that converges to a limit in $(a,b)$ which is contained in none of the closed intervals. Is my proof correct?

Can you express $[0,1]$ as a countable disjoint union of closed sets, other than the trivial way of doing this?


I am looking for a simple command in GNU/Linux to count all files in a directory beginning with pa.   I have already executed the command to show all the files beginning with pa which I used find /etc/file/magic -name "pa*" and it shows up 4.  However, I need a command to actually count this.

How can I use word counter (wc) and piping to count how many files or directories are in the /usr/bin directory?


I have a class Array  template <typename T> class Array : public SequentialContainer<T>{ public:     Array(Int size){local_vector.reserve(size);}     Array(std::initializer_list<T> initializer_list){         local_vector.assign(initializer_list);     }     virtual Boolean contains(T &object) const;     virtual Boolean contains(Container<T> &container) const;     virtual Int size() const;     virtual T &operator[](Int idx);     virtual T &get(Int idx);     virtual void set(Int idx, const T &object);     virtual Int indexOf(T &object);     virtual Iterator<T> iterator() const; };   All the methods are implemented like this in the Array.cpp file:  template <typename T> Boolean Array<T>::contains(T &object) const { //code }   If i try to use this Array class in a main.cpp file:  Array<int> c = {1, 2, 3, 4, 5, 6}; std::cout << c.[4] <<std::endl;   I am getting these linker errors:  undefined reference to `Array<int>::iterator() const' undefined reference to `Array<int>::contains(int&) const' undefined reference to `Array<int>::contains(Container<int>&) const' etc...   for every single method of the Array class. All the files are in my cmake file and should be compiled. Why I am getting this linker error? could someone explain me this please?

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


In the TNG episode "", we see Data's travel bag opened to show various items of relevance.  On it, it appears that Data has some other titles, names, or honorifics.  It reads as “Lt.Cmdr. ???/??? Data”, where between his (known) name and rank there seems to perhaps be text (possibly a series of acronyms?) but it's not clear.  Are these symbols simply patterns and line art filling up space, or is there some other meaning here?

What is the full official name Doctor Noonien Soong gave to his android (known in ST: TNG as "Data")?   Is the entire name simply Data, or is it an acronym?


So, I'm working on a little arena map for my friends and me and I need to give a weird invisibility totem. The person should get five and It consumes all of them at once if I stack them so I need to spread the out in the hotbar. I am using /give to give all five and am using 5 different command blocks. I am using a separate detection system for each totem but this is the command I have so far:  give @a[scores={assassin=1..}] minecraft:wither_skeleton_skull{slot:1b,display:{Name:"{\"text\":\"Invisibility Totem\",\"color\":\"gray\",\"strikethrough\":\"true\"}"}} 1   It's the part at the beginning of the NBT tags that says: slot:1b, the command works perfectly otherwise. Anyone know what I should use there or if they still have this in the game as of 1.13?

I am currently working on a project. For this project, I would like to prevent items from stacking. Is there a way to do this with commands?


This is an exercise from Stein-Shakarchi.  Suppose that $f$ is holomorphic in an open set containing the closed unit disc, except for a pole at $z_{0}$ on the unit circle. Show that if $f(z) = \sum_{0}^{\infty}a_{n}z^{n}$ in the open unit disc then$$\lim_{n\rightarrow +\infty} \frac{a_{n}}{a_{n+1}} = z_{0}$$  Any hint ?

This is my first question in mathSE, hope that it is suitable here!  I'm currently self-studying complex analysis using the book by Stein & Shakarchi, and this is one of the exercises (p.67, Q14) that I have no idea where to start.     Suppose $f$ is holomorphic in an open set $\Omega$ that contains the closed unit disc, except for a pole at $z_0$ on the unit circle. Show that if $f$ has the power series expansion $\sum_{n=0}^\infty a_n z^n$ in the open unit disc, then      $\displaystyle \lim_{n \to \infty} \frac{a_n}{a_{n+1}} = z_0$.   If the limit is taking on $|\frac{a_n}{a_{n+1}}|$ and assume the limit exists, by the radius of convergence we know that the answer is $1$. But what can we say about the limit of the coefficient ratio, which is a pure complex number? I've tried to expand the limit directly by definition, with no luck. And I couldn't see how we can apply any of the standard theorems in complex analysis.  I hope to get some initial directions about how we can start thinking on the problem, rather than a full answer. Thank you for the help!


Suppose that a set $A$ is denumerable. Prove that there is a partition $P$ of $A$ where $P$ is denumerable and every $X \in P$ is also denumerable.  I can see that this can be done but I cannot figure out how to construct it where every $X \in P$ is denumerable and not finite. Any ideas here?

Is it possible to have a countable infinite number of countable infinite sets such that no two sets share an element and their union is the positive integers?


I am trying to create a database and whenever I try to select + print the data it prints an "u" before any value and I have no idea why it does that?!   import sqlite3  conn = sqlite3.connect('learner.db')  c = conn.cursor()  # c.execute("""CREATE TABLE learners ( #           ID varchar, #           name text,  #           age integer, #           email varchar, #           goal varchar, #           reason varchar, #           budget integer, #           keyword1 varchar, #           keyword2 varchar, #           keyword3 varchar, #           keyword4 varchar #           )""")  c.execute("INSERT INTO learners VALUES ('L01','Leon','23','hi@max.com','I want to loose some weight','marriage is not far away','30','weightloss','fitness','health','nutrition')")   c.execute("SELECT * FROM learners WHERE name='Leon'") print(c.fetchone())   conn.commit()  conn.close()    And this is what I get:   (u'L01', u'Leon', 23, u'hi@max.com', u'I want to loose some weight', u'marriage is not far away', 30, u'weightloss', u'fitness', u'health', u'nutrition')    Why is there an "u" in front of the values?!   Thank you so much for your help!

This will surely be an easy one but it is really bugging me.   I have a script that reads in a webpage and uses  to parse it. From the soup I extract all the links as my final goal is to print out the link.contents.  All of the text that I am parsing is ASCII. I know that Python treats strings as unicode, and I am sure this is very handy, just of no use in my wee script.   Every time I go to print out a variable that holds 'String' I get [u'String'] printed to the screen. Is there a simple way of getting this back into just ascii or should I write a regex to strip it?


Why can't moderators see who flagged a comment?  I read  on the topic, but I don't really understand Shog's response on the linked post - maybe it would've made sense to me if I was on SO in 2010, but from where I stand now, I don't really see what all this talk about discouraging people from flagging has to do with anything.

There are three types of flags moderators get to deal with--standard flags (low quality, other), spam/offensive flags, and comment flags.  Within the moderator dashboard, we can see who has submitted a standard flag.  However, we do not see who has submitted an offensive/spam flag nor a comment flag.  Is there a reason for this?  If not, I'd like to be able to see the name of the user who has submitted a flag, no matter what type.    For those scoffers who scoffed at me:    Now, how should I handle this situation?  I could guess at who did this, but it would only be a guess.  Scoffers suck.


in my mariadb i have replication, i tried to change the location of the binlogs by changing the configuration file as so: log-bin = /new/path/mysql-bin I also tried to change the index location as so: log_bin_index = /new/path/mysql-bin.index but every time when I restart I see that the location of the binlog files is /var/lib/mysql... i tried to check with mysqld --verbos --help | grep bin and I saw that the lob-bin parameter is mysql-bin and not what I wrote in the cnf... how to I make the MySQL to take the value of the log-bin from the cnf file? this is the cnf file of the MySQL for sure...

I am new to linux, and i just installed MySQL-server-5.1.59-1.glibc23.i386.rpm in my linux machine.   I wanted to know where my.cnf file gets stored..? Will my.cnf gets created with the installation or not..?  I am using Fedora core 13  Edited: Still i am not able to find this file. When i asked my admin, he is telling we need to copy my-large.cnf and place in /etc folder.. is it so...?


I'm really confused about the visitor pattern and its uses. I can't really seem to visualize the benefits of using this pattern or its purpose. If someone could explain with examples if possible that would be great.

I keep seeing references to the visitor pattern in blogs but I've got to admit, I just don't get it.  I read the  and I understand its mechanics but I'm still confused as to when I'd use it.  As someone who just recently really got the decorator pattern and is now seeing uses for it absolutely everywhere I'd like to be able to really understand intuitively this seemingly handy pattern as well.


We are going through the process of hardening Amazon Linux 1 based on .  Control 5.2.12 states under "Expected Values" :     The following List String value(s) X indicate the current   status of the MACs setting defined within the   /etc/ssh/sshd_config file.      ======Expected Value(s)======   contains regular expression list   hmac-sha2-512-etm@openssh.com   hmac-sha2-256-etm@openssh.com   umac-128-etm@openssh.com   hmac-sha2-512 hmac-sha2-256   umac-128@openssh.com   curve25519-sha256@libssh.org   diffie-hellman-group-exchange-sha256   Based on  RHEL documentation of the setting, we appended the following to /etc/ssh/sshd_config:  MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256    /etc/init.d/sshd restart results in the following error:     Starting sshd: /etc/ssh/sshd_config line 142: Bad SSH2 Mac spec   'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256'. [FAILED]    How do we configure SSHD MACs on Amazon Linux?

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


DECLARE @combinedString VARCHAR(MAX)  SELECT  @combinedString = COALESCE(@combinedString + ', ', '') + DriversTransportDetails.DriverName from DriversTransportDetails   select  trID, @combinedString as C  from DriversTransportDetails  group by DriversTransportDetails.trID    This is my code, I have table called DriversTransportDetails which contains columns trID (int) and driverName (nvarchar)  trID is not unique so trID can be in multiple rows depends on drivers, ex :  TrID  DriverName 1     Tony 1     Rony 2     Jeorge 3     Jim   I want to COALESCE driver name rows into one row, desired result :  TrID   C 1      Tony, Rony 2      Jeorge 3      Jim   The problem is the result is not correct, it shows all drivers combined into column c, like this :  TrID   C 1      Tony, Rony, Jeorge, Jim 2      Tony, Rony, Jeorge, Jim 3      Tony, Rony, Jeorge, Jim   What's the problem ?  Thank you very much :)

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


I have been asked to encrypt a URL parameter for a project that sends the customer to a non-marketing cloud corporate site. Encryption is easy enough:    set @encryptedString = EncryptSymmetric(@string, "AES", @null, @password, @null, @salt, @null, @vector)   set @encodedEncryptedString = Base64Encode(@encryptedSring)   However, the website developers are having some trouble decrypting the encoded and encrypted string. Given the password, salt, and vector, how can we decrypt this string? Can someone point me to some documentation that would describe the process?

We want to encrypt / encode URL parameters on our pages. I tried to encrypt a parameter using  with AES algorithm as explained in the   %%[SET @encData=EncryptSymmetric("test", "AES", @null, "1111", @null, "0000000000000000", @null, "00000000000000000000000000000000") ]%% AES: %%=v(@encData)=%%   The result of this function is      AT1r0irnzM+Ax1j8zN+zAw==   Then I tried to decrypt the value using an , but I always received an error message.  I suppose there is a difference between AES algorithm in Marketing Cloud and AES used in the online tool. Indeed if I encrypt the same word with an online tool (128-bit), I received this result      l4Yo3sFofFD1EMmtoh397w==   Do you have any deep information regarding this function? What could be the difference?


I googled it and all I got was how to transfer files from one domain to another domain.  Say I have two PCs, one running windows server 2008 and the other running Windows 7, they're connected via a LAN, and they're part of the same domain.  How do you send a file from one PC to the other?  Why the heck isn't there some simple function where you right click a file and select send?

How can I setup a share on a client computer in a Windows 2012 Essentials domain?  I have 2 PCs logged into this domain, and I would like to share computer A's documents with computer B.  Is there a way to do this?


Once upon a long time ago, the Nielson Ratings were determined by set top box. They were pretty decently accurate, or at least accepted as so by the big three original networks. Now that there are eleventy hundred channels to watch, how are ratings determined?

I was interested to find out that in the 1950s, Nielsen used devices in the homes of the families that were surveyed to record their viewing preferences, and only later introduced their system of using a diary to record habits:  ...in 1950...This information was collected on a device that was attached to a television that recorded what was being watched.  In 1953, the company began sending out diaries to a smaller sample of homes (“Nielsen families”) within the survey to have them record what they had watched from   So, presumably as multiple different viewers in the home were considered in the sample, the means through which the ratings were recorded changed. Given that so many people are able to record shows digitally and watch when convenient and that so many view their favorites on outlets such as iTunes, how have the Nielsen ratings systems adapted (or how does the company plan to adapt them) to capture our modern viewing preferences? While a DVR-recorded show still technically makes its original "timeslot" relevant to the equation, will Nielsen consider timeslot-specific data a hindrance to comparisons between those shows viewed on cable and the same show viewed on iTunes?


Is possible for grep, or egrep to see the exact word? See this example: those are my groups groups floppy audio video cdrom games plugdev power netdev scanner users  I want to see only power, but return the entire line groups |grep --color -w power floppy audio video cdrom games plugdev power netdev scanner users  Is easy to return only power using pipe with awk or cut groups |grep --color -w power|cut -d ' ' -f 9 power  but my question is: is possible for grep or egrep command to return the exact word only?

I'm entering the world of Linux and at work I'm using grep more and more.  By doing that I'm figuring out that sometimes it's not adequate for what I want.  I was struggling with grep a few days ago and a colleague of mine who is a senior Linux admin, told me to use awk. I was stunned by how fast I got a result.  So my question is when do you choose to use one over the other? What questions can I ask myself before going to work with grep and spending a lot of time, when I could have done it with awk and saved time?


Is it possible that Google crawler doesn't fetch all the content on the page when it's size is 1.6 MB? How does Google treat big documents?

I have a 10MB HTML file. Will Google crawl through the entire file, or does it only look at the first X MB?


I'm reading Stewart's calculus book and I faced with an intuitive issue.  Intuitively, I don't understand why since both graphs looks like the same up to a zoom in/out. Could someone explain to me this intuitively? For me both should be convergent in this context.  It's difficult to grasp this intuitively because it's like both functions are approaching to zero without the area of the second one approaching to zero, how is that possible?

I am aware that the area under the curve of $\frac{1}{x}$ is infinite yet the area under the curve of $\frac{1}{x^2}$ is finite.   Calculus and series wise, I understand what is going on, but I can't seem to get a good geometric intuition of the problem. Both curves can be shown to converge to $0$ (the curves themselves, not the area), and on the interval from $1$ to infinity, the two curves have nothing intrinsically different. Can someone please provide me with an good geometric intuition of what's going on? I can't find anything on the web, people seem to not want to explain it geometrically.


I was told here, that it is insane to add repeatedly new ppa-s to the system, however sometimes it is the only way for me to install a program. Some programs have different ppa-s on launchpad.net to choose from, is there a  way to tell, or at least make an educated guess, if one ppa is potentially less harmful than another?

I see a lot of interesting programs out there that can only be obtained by adding a "PPA" to the system but, if I'm understanding correctly, we should stay within the official "repositories" for adding software to our system.   Is there any way for a novice to know if a "PPA" is safe or if it should be avoided? What tips should the user know about when dealing with a PPA?.


I stumbled across an hyphenation problem which I cannot explain or solve. When I use a narrow box containing a long word with a width longer than the box width, this word is not hyphenated.  The following MWE uses the long word Rechnungsadjunktentochter with an explicit hyphenation pattern in the preamble. This word is hyphenated in a long text, also when the break points are given in a narrow box locally, but it is not hyphenated automatically.  What happens here? And, more important, how can I get my words hyphenated automatically as expected?  UPDATE: @egregs comments explain what happens. But, still, I would have to insert \hspace{0pt} at every first word of every paragraph of every narrow box (and I have MANY of them, partly automatically generated). How can I force TeX to hyphenate the first word of EVERY paragraph (inside an environment) automatically?  UPDATE 2: The solving answer is given by the latter comments of @egreg to this question.  \documentclass{article}  \hyphenation{%   Rech-nungs-ad-junk-ten-toch-ter }  \begin{document}  \textit{Works even without the special hyphenation pattern:}\\ bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla Rechnungsadjunktentochter  \bigskip \textit{Local hyphenation pattern works as expected:}\\ \fbox{\begin{minipage}{3cm} Rech\-nungs\-ad\-junk\-ten\-toch\-ter \end{minipage}}  \bigskip \textit{\bfseries Hyphenation pattern from the preamble does not work as expected:}\\ \fbox{\begin{minipage}{3cm} Rechnungsadjunktentochter \end{minipage}}  \end{document}

I'm having some problems with lines that turn out to be too long. There are correct hyphenation rules for the word but they aren't being applied.  Let me first give the sentence that is too long:  An isomorphism that maps a graph to itself is called an \concept{automorphism}.   The command concept is defined as follows  \newcommand{\concept}[1]{\index{#1}\marginpar{\raggedright\textbf{#1}}\textbf{#1}}   The problem seems to be that words inside \concept aren't being hyphenated. How can I fix this? If I type   An isomorphism that maps a graph to itself is called an \textbf{automorphism}.   then the word is hyphenated perfectly. So I would now like to have the command \concept behave the same way, i.e. allow concepts to be hyphenated according to the standard rules.


I recently installed Windows 10 using Bootcamp. When I try to turn up the audio nothing happens. I went into device manager and the High Definition Audio Controller has a triangle with an exclamation mark over it. I tried to update the drivers but it said they were already up to date.

Windows 8.1 isn't playing back audio on my 13" mid-2012 Macbook Pro.  I only have a speaker with an x on my notifications bar.  When I click on it, I get the usual "detecting problems" garbage.  Unfortunately, every "solution" I've found seems to work for everyone else, but not for me.    Device Manager  Windows shows a High Definition Audio Controller listed under System.  Its properties state that it has a Code 10 - "This device cannot start", along with "The requested operation was unsuccessful."  This is the only notion of an audio device listed in Device Manager.  Most solutions I've found say drivers need to be reinstalled (downloaded from the internet or simpliy re-run from the Bootcamp support drivers) and I've currently tried the following:   Bootcamp setup.exe (No errors are reported, 5.0.5033 "installs" a variety of sound drivers) Cirrus Audio (Both CirrusAudiox64.exe and a manual .inf installation) Realtek (I've tried nearly every link I've found)  Intel Graphics 4000 (apparently it does audio too)   Every executable runs and reports success, however, I don't see any sign of a change apart from the Realtek driver copying files somewhere in Program Files, and the Intel driver blanking the screen a few times.    Cirrus Audio  I've tried manually installing the Cirrus Audio driver by performing the following:   Select High Definition Audio Controller from Device Manager Click on Driver -> Update Driver Select "Browse my computer for driver " Select "Let me pick from a list of device drivers" Click "Have Disk..." and navigate to the .inf file   At this point windows complains that the driver does not support Windows x64, despite having "x64" written all over it.  "The folder you specified doesn't contain a compatible software driver for your device. If the folder contains a driver, make sure it is designed to work with Windows for x64-based systems."  If I skip #'s 4 and 5, and browse directly for the driver files, Windows reports that the Driver software is already up to date.  "Windows has determined the driver software for your device is up to date."  This makes me believe that Windows 8.1 might have an issue with certain drivers, deeming them unusable in some way.  It's possible that windows is denying the .exe installers' drivers, Realtek, and Cirrus behind the scenes, without letting them install anything.  Maybe they report success and silently fail?    Setup  It's worth mentioning that my Bootcamp setup isn't typical.  I've partitioned the hard drive and installed windows manually, alongside Arch Linux.  (I've triple booted this thing, and windows audio is the final hurdle.)  I'm also using the refind efi bootloader to boot the system.  For the windows boot option, I point refind to /EFI/Microsoft/bootmgfw.efi, without any options. I'm thinking that Bootcamp might do more than partition and install, and that I'm supposed to do more to inform windows about the macbook hardware at this stage.  Is this the case?  Did I miss something critical about Bootcamp?    If anyone can help me solve this, I will be eternally grateful.  Thanks.  P.S. I'm a linux user, so windows drivers aren't exactly my forte.  If I'm doing something totally wrong, please let me know.


I'm working under Sun Studio 12.3 on SunOS 5.11 (Solaris 11.3). Its providing a spurious warning:     "<file.h>", line 1: Warning: "<function>" is expected to return a value.   The function is part of a base class interface and looks like so. I only mention the base class interface to avoid the "why would you do that" discussions. A non-member function like below is enough to trigger it.  int foo() {     throw runtime_error("Not implemented"); }   I found mention of similar problems. For example, the  change log states:        Disable " is expected to return a value" warning from Sun's C++   compiler, as it fires for functions ending in a "throw" statement.  Genuine   instances will be caught by compilers with superior warning machinery.      According to , I can use -erroff=voidretw. I'm concerned about -erroff=voidretw because it might suppress valid findings. Also, if I go with the #pragma, then I need to push and pop it to avoid cross pollinating into user code. I don't know how to push and pop warning states under Sun Studio.  My question is, how do I disable the warning for the one function in the header under Sun Studio?    This looks like a duplicate even though the message is different:  I think I am going to vote to close this as a duplicate.

The STLport bundled with the SunStudio11 generates alot of warnings. I beleive most compilers have a way to disable warnings from certain source files, like this:  Sun C  #pragma error_messages off  #include <header.h> // ...  #pragma error_messages on   gcc  #pragma warning(push, 0)          #include <header.h> // ...  #pragma warning(pop)   How do you do this in the SunStudio C++ compiler? (btw, the sunstudio C pragmas don't work in sunstudio C++)


I keep home directories on a separate /home partition.  When I reinstall Ubuntu (generally Ubuntu-Mate), I format the root partition but keep /home and create user accounts in the same order with the same user names and passwords.  When upgrading to Ubuntu 16 years ago, this worked seamlessly; old home directories decrypted just fine. Now I just reinstalled up to Ubuntu 20.04.2.  I checked around and it looked like everything should work the same as last time.  I recreated the same user account with the same username and password but it won't unencrypt the old home directory.  I can log in from the terminal to check things out but the graphical login just takes my password then kicks me back out. Did something change in Ubuntu 20 that's causing the problem?  Where can I look to track down the problem?  Or was there something necessary to decrypt the drives that I blasted when I reinstalled and formatted the root partition?

1. What will happen when upgrading Ubuntu 17.10 with encrypted /home to Ubuntu 18.04?    Other base system changes since 16.04 LTS:  The installer no longer offers the encrypted home option using ecryptfs-utils. It is recommended to use full-disk encryption instead for this release.   2. Will 18.04 be able to use encrypted  (ecryptfs) /home ?  edit: 3 is now a standalone


I'm new to learning Java. I started about a week ago, and have spent around 10 hours a day learning, and I'm not sure if I'm behind where I "should be" (another concern I'm dealing with)  I'm aware that my code is probably not the most efficient, but I have to start somewhere, and I've typed most of this out of memory from the cosmos of information I've read in the last week. Right now, I'm just trying to make games or apps to help solidify concepts of programming. To put what I've learned to use and make this information relevant.  my question is, essential, why are my "if" statements going directly to the "else"?  public class ClassSelect {  public static String className;  public static void pickPlayer() {      Scanner scan = new Scanner(System.in);     System.out.println("Pick your class." + "\n" + "[F]ighter" + "\n"             + "[W]izard");     String scanClass = scan.nextLine();      if ((scanClass == "f") || (scanClass == "F")) {         System.out.println("You picked the Fighter");         String classNameF = "Fighter";         className = classNameF;         try {             File file = new File("saveData.txt");             BufferedWriter output = new BufferedWriter(new FileWriter(file));             output.write(className);             output.close();         } catch (IOException e) {             e.printStackTrace();         }     }      else if ((scanClass == "w") || (scanClass == "W")) {         System.out.println("You picked the Wizard");         String classNameW = "Wizard";         className = classNameW;         try {             File file = new File("saveData.txt");             BufferedWriter output = new BufferedWriter(new FileWriter(file));             output.write(className);             output.close();         } catch (IOException e) {             e.printStackTrace();         }     } else {         System.out.println("You didn't choose either.");     } }

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


I have a list with some Person Object. Here is my Person class:  public class Person(){ // contructors   private String lastname;  private String firstname;  private List<Place> places;  // getters and setters }   My Place class is :  public class Place(){ // contructors   private String town;  // getters and setters }   I have code to remove some places from person:  List<Person> persons = new ArrayList<Person>(); // adding persons to List // Below i want to remove person whose place is in town Paris. persons.removeIf((Person person)-> person.getPlaces(???));   I want to remove a person from the list whose Place meets the following condition  place.getTown()=="Paris"  How to write this code?


My nginx configuration file is given below.  server {   listen 80;   server_name http://hg.rawdatatech.com;    location / {     proxy_pass http://127.0.0.1:8000;     proxy_set_header Host $host;     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;   }    location /static/ {     alias /home/home-garden/staticfiles/;   } }   When I run my Django application using this configuration I saw "suspicious symbol error" and connection refusing error nginx error log. Is there any wrong in my configuration?

I have the following nginx config, e.g.  server {         listen   80;         server_name example.com         allow 127.0.0.0/8;   When I restart, it warn me:  Restarting nginx: nginx: [warn] server name "127.0.0.0/8" has suspicious  symbols in /etc/nginx/sites-enabled/xxx   Any idea?


I have the name of a computer on the network, and I need to know how to get the ip address of said computer from a batch file? Thanks.

I need to know the ip address of another machine in a lan network.  What is the Windows command for getting ip address from machine name and vice versa?


Python newbie here. I've searched quite a bit for a solution to this but nothing quite fits what I need. I would like to allocate an empty array at the start of my program that has a rows and b columns. I came up with a solution but encountered an interesting problem that I didn't expect. Here's what I had:  a = 7 b = 5 array_ab = [['?'] * b] * a   which produces  [['?', '?', '?', '?', '?'],  ['?', '?', '?', '?', '?'],  ['?', '?', '?', '?', '?'],  ['?', '?', '?', '?', '?'],  ['?', '?', '?', '?', '?'],  ['?', '?', '?', '?', '?'],  ['?', '?', '?', '?', '?']]   However, if I try to change a single element, it treats every row as the same object and effectively changes the entire column to that element. So for example  array_ab[4][2] = '1'   produces  [['?', '?', '1', '?', '?'],  ['?', '?', '1', '?', '?'],  ['?', '?', '1', '?', '?'],  ['?', '?', '1', '?', '?'],  ['?', '?', '1', '?', '?'],  ['?', '?', '1', '?', '?'],  ['?', '?', '1', '?', '?']]   Clearly I need a better way to create the blank array than by multiplication. Is there a solution to this in python? (It was so simple in FORTRAN!)

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


I've made quite a few campaigns that my party has enjoyed quite a bit. I was thinking that since I am too young to have a job I could publish some of my campaigns. I have them all written in Google Docs but I dont know where and how to publish them.

I've had artistic skills since I was a kid and I love D&D, and I want to create some books. I would be trying to fund them with KickStarter — 100 new monsters, 100 NPCs, 100 map tiles, and stuff like that. I would be doing all the art.  Is this something I can do? Is copyright a problem, and if so is there any way to avoid those problems?


I know that $\mathbb{Z}$ is a group under addition with a multiplication defined. I have just the definition of even and odd integers: $n$ is even if $n = 2k$ for some integer $k$ and $n$ is odd if $n = 2k+1$ for some integer $k$.  Using just this I am wondering how to prove that all integers are either even or odd. That is, how can I prove that given an integer $n$, $n$ must be even or odd?  My problem with this is that it seems so simple. I know that one can divide an integer by $2$ and the remainder will be $0$ or $1$. Using this, it is clear that the even and odd integers make up everything. But how can I prove it without using this fact about remainders and such? I guess one could also use facts about prime numbers, but I am looking for a proof that just uses the definition of odd and even.

There is , but the definition of "even" and "odd" that I am using uses integers instead of just natural numbers; i.e.,   An integer $n$ is even iff there is some integer $k$ such that $n=2k$. An integer $n$ is odd iff there is some integer $k$ such that $n=2k+1$.   Here is what I have so far:  First we show that an integer $n$ is even or odd. We first use induction on the positive integers. For the base case, $1=2\cdot0+1$ so we are done. Now suppose inductively that $n$ is even or odd. If $n$ is even, then $n=2k$ for some $k$ so that $n+1=2k+1$ (odd). If $n$ is odd, then $n=2k+1$ for some $k$ so that $n+1=2(k+1)$ (even). This closes the induction, so every $n\in\mathbf{Z}^+$ is even or odd.  Now we show every $n\in\mathbf{Z}^-$ is even or odd. Let $n\in\mathbf{Z}^-$. Then $n=-k$ for some $k\in\mathbf{Z}$ (I think this follows immediately from most definitions of the integers.). Suppose $k$ is even. Then $k=2j$ for some $j$ so that $n=-k=-2j=2(-j)$ (even). Now suppose $k$ is odd. Then $k=2j+1$ for some $j$ so that $n=-k=-(2j+1)=-2j-1=-2j-1+1-1=-2j-2+1=2(-j-1)+1$ (odd).  For $0$, note that $0=2\cdot0$ (even).  Now we show that $n\in\mathbf{Z}$ cannot be both even and odd. Suppose for the sake of contradiction that $n\in\mathbf{Z}$ is both even and odd. Then there are integers $k,j$ such that $n=2k=2j+1$. This implies that $2(k-j)=1$ (like in the referenced question). So we must show that $1$ cannot be even in order to complete the proof.  This is where I am having trouble. I know that if I let $f:\mathbf{Z}\to\mathbf{Z};x\mapsto2x$ be a function, then $f$ is increasing so since $f(0)=0$ and $f(1)=2$ and $0<1<2$, there is no integer $m$ such that $f(m)=1$. But this seems complicated so I was wondering if there was an easier way to do this.  So my real question is: how can I show that $1$ is not even?  (This is not homework.)


I'm using GNOME.  In Windows, you can right-click on applications in the taskbar to see your most recently used files, and files you've chosen to stay in the dock. This is one of my most missed features since switching  Here's an example:    Is there a way to have this feature in Ubuntu?

In windows we have an option to view recently opened media files as my recent documents, I was  wondering does there exists something like that in Ubuntu?  via terminal or via GUI?


I just recently bought a used Orbea road bike. The tires are currently iRC Jetty 700x23c on Omega ETRTO 622x13c rims.  is possible to change my tires to a bigger ones than the existing/ Possibly changing to 28c tires.  I am using the road bike to commute to work and cycle leisure on weekends but in my area there are lot of tram lines. Twice I got stuck in them, which is quite scary and dangerous. So I'm hoping this is possible, as I can't afford to get new rims too. Not at the moment.

We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.   This is intended as a canonical question that we can point closed questions to.


I am learning game theory. I always see that professors write (in text books):   a player chooses her strategy  If she chooses a strategy   Also some professors use he instead of she.  There other names also like player, but I forgot about them now.  How can I know when to use she versus when to use he in these situations?

There are some questions on gender-neutral pronouns both  and on .  User Christine Letts :     In academia, there is currently a   movement toward using the feminine   pronoun at all times.   I wonder why that is. I came across several examples on papers I read, but the only one I can remember at the moment is a book: Seth Godin's . While some might not be comfortable labeling it as part of academia, it suits my point perfectly. Every time he refers to a person, he uses the feminine pronoun.  User Senseful  the following, potentially identifying affirmative action as the precursor for this trend.     I remember reading somewhere that it   was recommended to use the opposite of   what most people stereotype the   profession as. So, for example, when   talking about a chiropractor, you   would use "her", and when talking   about a secretary, you would use   "his".   So, where do you think this trend comes from?


For example:   Does the camera detect if the scene contains fast-moving objects and if so use a shorter shutter speed? Does it detect if the entire scene is beyond the hyperfocal distance, and there's plenty of light, and automatically use an aperture at which the lens is the sharpest? Put differently, does it use the sharpest aperture unless there's a reason not to? Alternatively, does the camera detect if I'm shooting a portrait and switch to the widest aperture to de-focus the background?   Is there any intelligence at all here? Can I rely on the camera to pick the right aperture the vast majority of time, like I can with metering, and with focus when there's enough light?  Obviously, when I want to use a particular setting for a certain creative effect, I specify that, and not leave it to the camera. For example, if I'm shooting a train under low-light, I might choose a several second exposure to make the train appear milky, or a 1/4 - 1/2 second exposure to create some blur while still retaining distinct objects to some extent, or an even shorter exposure to freeze the motion. Obviously, I can't expect the camera to guess what I have have in my mind. This question is not about these cases. It's about cases where there's an obvious default that's right the majority of time. Can I rely on the camera to pick these?  In case the answer depends on the camera, this is with reference to the Sony NEX-5R.  When I say "an automatic mode", I mean automatic, program, shutter-speed priority and aperture priority modes. In the latter two modes, the camera still has to choose between ISO and aperture / shutter speed.

In program mode, DSLRs adjust not only the ISO and the shutter speed, but also the aperture.  The aperture has a huge impact in some situations. For example, when shooting a close subject in front of a meaningless background, the aperture must be large so the background is blurred as much as possible; on the other hand, when shooting landscape, nobody wants a ƒ/1.4. How do cameras determine the aperture to set? More precisely:   Are there some general rules applied by most brands? If not, given some camera model as an example, what rules are applied by this camera?


How to disable those annoying notifications when you plug a new disk in, or connect to a network and so on....  I know that if I add a device to a mount script they will be mounted on boot thus not showing me the notification, which I did for my hard drives, but it doesn't help with all those flash disks I have... I can't add them all that would be silly.  I looked at:    ... but they didn't help, since the code was different  I also looked at configuration editor, but I think it can only disable auto-mount when inserted, it doesn't disable notification...

I have an NFS drive mapped in Ubuntu 11.10 using autofs which automatically mounts a drive on every boot. But if I use the Gnome Shell interface, a pop up notification keeps popping up from the bottom-centre of the screen saying the name of the mapped drive and an Eject option.  It pops up about every 5 minutes even though the NFS drive is already always mounted. Any way to stop this?


Say a friend wants to schedule a time to hang out, but I'm not sure when I'll be available, so we set a place-holder time that may be when we hang out or may not. What is this called? I feel like there's a word starting with 't' that works, but 'temporary time' doesn't sound right.  Eg "I'm not sure when I'm free so lets set a * time and we can see if we need to change it"

Let's say a friend of mine tells me the following:     Nice! Let’s meet up for a drink this week.   And I want to say, "Sure let's do it. I will propose a few ..., and you tell me if either of them works for you."  I cannot come up with an idiom or other expression that works.


I've read quite a few explanations on this topic, liking this one the most:      But there is still one thing I don't understand.   I understand that the inverse of the covariance would deal with transformation of the (x-mu) to the standard gaussian. What I don't get is how is x^T infected by it?  To me, it seems that the we then take the dot product of elements 2 and 3 of the product, we transform only the (x-mu), and the first vector (x-mu)_transposed stays the same. So in the end we would get the dot product between the original vector and the transformed one.

I'm studying pattern recognition and statistics and almost every book I open on the subject I bump into the concept of Mahalanobis distance. The books give sort of intuitive explanations, but still not good enough ones for me to actually really understand what is going on. If someone would ask me "What is the Mahalanobis distance?" I could only answer: "It's this nice thing, which measures distance of some kind" :)   The definitions usually also contain eigenvectors and eigenvalues, which I have a little trouble connecting to the Mahalanobis distance. I understand the definition of eigenvectors and eigenvalues, but how are they related to the Mahalanobis distance? Does it have something to do with changing the base in Linear Algebra etc.?  I have also read these former questions on the subject:       I have also read .  The answers are good and pictures nice, but still I don't really get it...I have an idea but it's still in the dark. Can someone give a "How would you explain it to your grandma"-explanation so that I could finally wrap this up and never again wonder what the heck is a Mahalanobis distance? :) Where does it come from, what, why?   UPDATE:   Here is something which helps understanding the Mahalanobis formula:


let $R$ be a ring, if every element $x$ satisfies $x^3=x$ then show that $R$ is commutative.  Yes, I have read the other two posts regarding this question, and saw many many solutions, however none seems to explain how they arrive at the solution?  Can someone care to show me some advice on how might one arrive at a solution for these problem? Not just the proof itself but how it could have been deduced?  Or is this one of those problems you just have to try different things until you lead to something that works?  thank you

Let $R$ be a ring, where $a^{3} = a$ for all $a\in R$. Prove that $R$ must be a commutative ring.


I have this problem set question and I am not sure if I am overthinking it or not.     Suppose you are driving at velocity $v$ on a horizontal road that has a coefficient of static friction $µ_s$ with the tires. You need to stop suddenly and step on the brakes. If the road is straight, what is the maximum possible deceleration?   So far I have started by saying that the car exerts a force forward (mass of car X acceleration of car) and friction acts in the opposite direction of the car.  When the car is braking, it essentially stopping and sliding across the surface. How do I relate this to the velocity?  Edit: Is it overthinking the question to say that the car is initially constantly accelerating to maintain a constant velocity and then to use that information to my advantage i.e as part of a system?

I am trying to calculate the minimum stopping distance of a car once the brakes are applied. I know that $F = ma$, and the braking force is $F = \mu N = \mu m g$, so $$a = \mu g.$$ Next, by applying the kinematics equation $$v_f^2 - v_i^2 = 2 a x$$ I found $$v^2 = 2 a d$$ where $a$ is the deceleration, $v$ is the initial velocity, and $d$ is the stopping distance. Then $$d = \frac{v^2}{2a} = \frac{v^2}{2 \mu g}.$$ Is this reasoning right?


I used two different methods to retrieve a list of 1808 and 867 elements from a list of 3431 elements. The two lists (1808 and 867) have 683 elements in common. This shows that the two approaches produce results that highly overlap but I want to calculate statistics to prove this. I looked into it and found hypergeometric test to be a relevant test. But I am not sure how to perform the test on my data set. I assume hypergeometric test can take four variable as input but I have five. Basically, I want to know if I pick 1808 elements from 3431 elements and 867 elements out of 3431 elements, what is the probability that their will be 683 elements in common.  PS: I also think this test is a without replacement test.

Hopefully someone on these forums can help me out with this basic problem in gene expression studies.  I did deep sequencing of an experimental and a control tissue. I then obtained fold enrichment values of genes in the experimental sample over control. The reference genome has ~15,000 genes. 3,000 out of 15,000 genes are enriched above a certain cut-off in my sample of interest compared to control.  So:  A = total gene population = 15,000 B = RNA-Seq enriched subpopulation = 3,000.  In a previous ChIP-chip experiment, I found 400 genes that are enriched by ChIP-chip. Of the 400 ChIP-chip genes, 100 genes are in the group of 3,000 enriched RNA-Seq transcripts.  So: C= total # of ChIP-chip enriched genes = 400.  What is the probability that my 100 ChIP-chip genes would be enriched by RNA-Seq by chance alone? In other words, what is the most prudent way to calculate if my observed overlap between B and C (100 genes) is any better than that obtained by chance alone? From what I have read so far, the best way to test this is by using hypergeometric distribution.  I used an online calculator (stattrek.com) to set up a hypergeometric distribution test with the following parameters:  - pop size=15,000 - # of successes in population=3,000 - sample size=400,  -# of successes in sample=100.  I get the following for Hypergeometric Probability P(x=100)= 0.00224050636447747  The actual # of genes overlapping between B and C = 100. Is this better than by chance alone? Doesn't look like it is if the chance of any one gene being enriched is 1:5 (3,000 out of 15,000). That's why I don't understand how come my P(x=100) I calculated above is 0.0022. That amounts to a 0.2% chance of the overlap occurring by chance. Shouldn't this be much higher?  If I sampled 400 random genes rom the big list of 15,000, then any 80 of these genes would be expected to be enriched by chance alone (1:5). The number of genes that are actually overlapping is 100, so this is just slightly better than by chance.   I also tried to come up with a solution using the dhyper or phyper functions in R (using what I saw in another post): A=all genes in the genome (15,000) B=RNA-Seq enriched genes  (3,000) C=ChIP-chip enriched genes (400) Here's the R input/output (adapted from a previous stackexchange post):  > totalpop <- 15000     > sample1 <- 3000     > sample2 <- 400     > dhyper(0:2, sample1, totalpop-sample1, sample2)     [1] 4.431784e-40 4.584209e-38 2.364018e-36     > phyper(-1:2, sample1, totalpop-sample1, sample2)     [1] 0.000000e+00 4.431784e-40 4.628526e-38 2.410304e-36       I'm not sure how to interpret these numbers. I believe 2.36e-36 is the probability of getting a complete overlap between B and C by chance alone? But this makes no sense, since that probability is much closer to 1:5. If I start with 15,000 genes, 3,000 will be enriched. Similarly, if I start with 400 ChIP-chip genes, 80 of them should be enriched in the RNA-Seq alone due to the 1:5 chances of enrichment in that data set.  What is the proper way to calculate the p-value, according to the hypergeometric distribution, for the overlap of B and C?


So I'm curious as why $\mathbb{R} \subseteq \mathbb{R}^{2}$, since $\mathbb{R}^{2} = \mathbb{R} \times \mathbb{R} = \left \{ (a,b) \mid a\in \mathbb{R}, b\in \mathbb{R} \right \}$. Do we think of $\mathbb{R}$ as being $\mathbb{R} \times 0$ in this case?

Is it correct to say that $\mathbb{R}$ is a subset of $\mathbb{R}^2$? Or, put more generally, given $n,m\in\mathbb{N}$, $n<m$, is $\mathbb{R}^n$ a subset of $\mathbb{R}^m$?  Also, strictly related to that: what is then the "relationship" between the set $\{(x,0)\in\mathbb{R}^2,x\in\mathbb{R}\}\subset\mathbb{R}^2$ and $\mathbb{R}$? Do they coincide (I would say no)? As vector spaces, do they have the same dimension (I would say yes)?  If you could give me a reference book for this kind of stuff, I would really appreciate it.  Thank you very much in advance.  (Please correct the tags if they are not appropriate)


I met someone and we have been chatting via phone for awhile. He asked me to access his bank account and transfer money to someone else because he is in Thailand on business and he can't access his account.  His bank is the ISBank and is not available in Thailand. He didn't transfer money to me and hasn't asked me for money. Is this a scam?

A person I've been talking to for a while asked me to go into his bank account  and make a transfer to a US beneficiary account. It's a continental account. It showed the  date that the account was opened in 2007 as well as a picture of him.   I trusted him and I did it. Now he is asking me to do it again and this time red flags are coming up. Can someone help me? Is it illegal to go into someone's account and make a transfer for them?


I have just started a . I just got things going, and was about to install tmux, and was hit with the message...  Error: This command has to be run under the root user   Ok. I attempt to run  sudo dnf install tmux   And now I get hit with the error  <my username> is not in the sudoers file. This incident will be reported.   I , using a command called visudo. However, it appears that this command too also requires access to sudo.   visudo visudo: /etc/sudoers: Permission denied   And with sudo  sudo visudo <password prompt> <my username> is not in the sudoers file. This incident will be reported   So it seems like I need to change the sudoers file to be able to use sudo, but I cannot change the sudoers file without sudo. What do I do??

I want to give a Fedora user sudo privileges. How do I do that?


I'm playing around with this op amp: . My circuit looks like this:  It is hooked up to an Arduino Uno. I used analog read on the Arduino to read voltages at 2, 3, and 6. The pot allows me to vary the voltage at 3 from 0 to 5 V. With R1 = R2 = 10K, I should have a gain of 2. I should be able to vary the voltage at 3 from 0 to 2.5 V and the output of the op amp should go from 0 to 5 V, right? I know I probably wont get quite to 0 or 5 V but pretty close. However, the plot below is what I measure with the Arduino. As far as I can tell, the analog read value of 0 is 0 V and 1000 is about 5 V.  So the op amp appears to work but only in a vary narrow range. It looks like its pretty close to the upper limit, but doesn't get anywhere close to outputting 0 V. Also, if I replace R1 with a higher resistance or R2 with a lower resistance, giving me higher gain, I get no response at all at the output. A3 remains at a constant value of around 800 no matter what the input is. I'm new to op amps so I'm probably missing something obvious... Thanks!

Simple enough question. Why not use a  in a target circuit or anyone's target circuit? What are the reasons not to use it? What might be the reasons to still choose this part?


I have this question:  Considering $$(1+x)^n(1+x)^n=(1+x)^{2n}$$ and show that: $${n \choose 0}^2+{n \choose 1}^2+{n\choose 2}^2+....+{n\choose n}^2={2n\choose n}$$  I have attempted so far: $$(1+1)^n={n \choose 0}+{n \choose 1}+{n\choose 2}+....+{n\choose n}$$ $$(1+1)^{2n}={2n \choose 0}+{2n \choose 1}+{2n\choose 2}+....+{2n\choose 2n}$$ $$\left({n \choose 0}+{n \choose 1}+{n\choose 2}+....+{n\choose n}\right)^2={2n \choose 0}+{2n \choose 1}+{2n\choose 2}+....+{2n\choose 2n}$$ and this is the part where I am confused about. Please help in where I got wrong and what I should do to show it in the correct method. The question here is to prove that $${n \choose 0}^2+{n \choose 1}^2+{n\choose 2}^2+....+{n\choose n}^2={2n\choose n}$$

I was hoping to find a more "mathematical" proof, instead of proving logically $\displaystyle \sum_{k = 0}^n {n \choose k}^2= {2n \choose n}$.  I already know the logical Proof:  $${n \choose k}^2 = {n \choose k}{ n \choose n-k}$$  Hence summation can be expressed as:  $$\binom{n}{0}\binom{n}{n} + \binom{n}{1}\binom{n}{n-1} + \cdots + \binom{n}{n}\binom{n}{0}$$  One can think of it as choosing $n$ people from a group of $2n$  (imagine dividing a group of $2n$ into $2$ groups of $n$ people each. I can get $k$ people from group $1$ and another $n-k$ people from group $2$. We do this from $k = 0$ to $n$.


Today I had a huge scare accidentally changing my laptop password to a keepass-generated 64-alphadigit string, locking me out of my encrypted homedir. My login password was stored in a keepass file on the encrypted homedir, mounted on a locked desktop which I could not unlock due to the password change. Luckily I have my mount passphrase and was easily able to have ecryptfs-recover-private mount to files on some /tmp-folder.  However, I don't just want to recover my files, also the operational part of my laptop automatically mounting them whenever I login, without accidentally destroying something that could indefinitely remove my access to the files. Hence Try-all and error of commands is not OK, I can easily do something I will regret. I could not find anything on the official ubuntu-page:    How do I reconfigure my encrypted homedir with my operating system and user account to function as before, given that my login-password is gone but my mount passphrase is available? Should I copy all my files to a proxy storage? The latter would be a pain, since I don't have the storage to duplicate my homedir.

I want to have an encrypted directory (not homedir!) let's say /testdata.  I have used the following command and parameters to encrypt it:  root@pc:~# mount -t ecryptfs /testdata/ /testdata/ Passphrase:  Select cipher:   1) aes: blocksize = 16; min keysize = 16; max keysize = 32  2) blowfish: blocksize = 8; min keysize = 16; max keysize = 56  3) des3_ede: blocksize = 8; min keysize = 24; max keysize = 24  4) twofish: blocksize = 16; min keysize = 16; max keysize = 32  5) cast6: blocksize = 16; min keysize = 16; max keysize = 32  6) cast5: blocksize = 8; min keysize = 5; max keysize = 16 Selection [aes]:  Select key bytes:   1) 16  2) 32  3) 24 Selection [16]:  Enable plaintext passthrough (y/n) [n]:  Enable filename encryption (y/n) [n]: y Filename Encryption Key (FNEK) Signature [b9fc92f854a4c85b]:  Attempting to mount with the following options:   ecryptfs_unlink_sigs   ecryptfs_fnek_sig=b9fc92f854a4c85b   ecryptfs_key_bytes=16   ecryptfs_cipher=aes   ecryptfs_sig=b9fc92f854a4c85b WARNING: Based on the contents of [/root/.ecryptfs/sig-cache.txt], it looks like you have never mounted with this key  before. This could mean that you have typed your  passphrase wrong.  Would you like to proceed with the mount (yes/no)? : yes Would you like to append sig [b9fc92f854a4c85b] to [/root/.ecryptfs/sig-cache.txt]  in order to avoid this warning in the future (yes/no)? : yes Successfully appended new sig to user sig cache file Mounted eCryptfs   This command creates this file:  root@pc:~# cat .ecryptfs/sig-cache.txt  b9fc92f854a4c85b   Now I want to change the passphrase I used before. I found the ecryptfs-rewrap-passphrase command but I am not sure if I am on the right path:  root@pc:~# ecryptfs-rewrap-passphrase .ecryptfs/sig-cache.txt  Old wrapping passphrase:  New wrapping passphrase:  New wrapping passphrase (again):  Error: Unwrapping passphrase failed [-5] Info: Check the system log for more information from libecryptfs   /var/log/syslog says:  Jul 13 13:16:19 pc ecryptfs-rewrap-passphrase: ecryptfs_unwrap_passphrase: PK11_CipherOp() error; SECFailure = [-1]; PORT_GetError() = [-8188]   I have a newbie status in regards to ecryptfs and I would appreciate some enlightenment here.


I am adding metadata to my document: \hypersetup{     pdftitle={ddd},     pdfsubject={aaa},     pdfauthor={xxx},     **pdfkeywords={666},**     pdfproducer={yyy!},  And there is a password string here, however the document does not ask for a password when opening it. How to password protect a document?

My questions is very simple. How can I set security setting for a PDF file created with PDFLatex?  I should set some password or print permissions, etc.


My friend has a computer with Ubuntu 12.04 32 bit, but he has no internet connection. He'd like to install the Adobe Flash Player on his computer. How to do that?

I have had significant problems with watching flash video in 64-bit Ubuntu.  Does anyone know of a good way to get flash running on the platform?


I'm trying to figure out why does it work like this when there's 2 verb in a single past sentence. for example, "I've never seen him dress like that before" and "I helped someone find their dog" Why do the bolded words remain in simple tense ? Shouldn't they be changed into past tense ? I can't seem to find the rule that explains this. Can you help elaborate what's going on here ?

What is the correct sentence :         What did you say?       or         What did you said?      The second sentence seems correct, but I am not certain.


Im having trouble figuring out that, if I'm in let say the directory /home/test/test2 but I want to find the number of files in the /home directory, how would I do it.   I know how to do it if it was the other way around, like in your home directory, list files in /home/test/test2, you would do:  ls /home/test/test2 | wc -l   but how would I do it if I was in the test2 directory and wanted to find the number of files in the home directory.  Thanks

If I do ls -1 target_dir | wc -l, I get a count of files in a directory. I find this a bit cumbersome. Is there a more elegant or succinct way?


Is it possible to "construct" the Hamiltonian of a system if its ground state wave function (or functional) is known? I understand one should not expect this to be generically true since the Hamiltonian contains more information (the full spectrum) than a single state vector. But are there any special cases where it's possible to obtain the Hamiltonian? Some examples would be really helpful.

A typical problem in quantum mechanics is to calculate the spectrum that corresponds to a given potential.    Is there a one to one correspondence between the potential and its spectrum?  If the answer to the previous question is yes, then given the spectrum, is there a systematic way to calculate the corresponding potential?


Those who know programming simply call this as DateTime. For example, "2015-12-22 03:11:25".  Instead of referring it to simply DateTime, is there any other suitable name?

I want one word that means Date and Time. For example in "the date and time of the event will be announced later" I want to use single word instead of "date and time"


Morning,  As I get closer to setting up my services etc for my website am I allowed to display the ubuntu logo? There are some that don't allow it.

Is there an Ubuntu logo that can be used on a commercial website to indicate that Ubuntu can be installed for customers?


Is there a built-in Python function that convert from digit number to hex string with zero leading digit?  I wrote her:  def convert_to_hex_string(number):     number = format(number, 'x')     if len(number) == 1:         number = '0' + number     return number  >>> convert_to_hex_string(7) '07' >>> convert_to_hex_string(10) '0a' >>> convert_to_hex_string(11) '0b' >>> convert_to_hex_string(666) '29a'   but I was wondering could already have a built-in in Python (analogue .toString("X2") in C#)

Given: a = 1 b = 10 c = 100  How do I display a leading zero for all numbers with less than two digits? This is the output I'm expecting: 01 10 100


I grew up using "preventive" approaches -- Now I see more often "preventative"   Similarly- market "oriented" no longer but "orientated"  When did this change happen? What is correct usage?

What are the origins of the word orientated?  As far as I know, the correct spelling is oriented and orientated is not an alternative spelling but an error that is in common use.  Is it for example more commonly used in a certain country or by a certain people? Is there a reason for people choosing to say or write orientated instead of oriented?


What is the best way to evaluate $8^{126}$ mod $9$?   So there is a path for $8^{126}$ :  $8^2 = **8$,  $8^3 = **4$,  $8^4 = **6$,  $8^5 = **8$,  $8^6 = **4$,  $8^7 = **6$,   so 126 should end with $**8$. $8$ mod $9$ is $8$.  I am not sure it's the way way to approach it, thanks!

How do I efficiently compute $a^b\bmod c$:  When $b$ is huge, for instance $5^{844325}\bmod 21$? When $b$ is less than $c$ but it would still be a lot of work to multiply $a$ by itself $b$ times, for instance $5^{69}\bmod 101$? When $(a,c)\ne1$, for instance $6^{103}\bmod 14$?  Are there any other tricks for evaluating exponents in modular arithmetic?  This is being asked in an effort to cut down on duplicates, see  and .


Prove by mathematical induction $$1^3 + 3^3 + \cdots + (2n - 1)^3 = n^2(2n^2-1),\forall n\geq1$$   Please help me solve this question using the mathematical induction method.

The series is $$P_k: 1^3 + 3^3 + 5^3 + ... + (2k-1)^3 = k^2(2k^2-1)$$ and I have to replace $P_k$ with $P_{k+1}$ to prove the series.  I have to show that $$k^2(2k^2-1) + (2k-1)^3 = (k+1)^2[2(k+1)^2-1]$$  I'm sorry that I'm asking but their are just so many factors the algebra just passes over my  head. Any help is appreciated.


Looking for a movie about time travel, possibly made in the 80s. The only scene I remember is set in a control center. Every time there is a change in the timeline, the present adjusts which causes everything to shake like an earthquake.

What is the title of a 80's (i believe?) movie where humans in the far future are going extinct, and are aquiring new humans by going back in time to todays world, kidnapping air travelers that are known to have died that day, from the flying passenger aircraft just before its crashing.  A key visual:    Inside a hangar, a time portal opened, and a tail of a (flying) passenger aircraft extruded into the hangar where a stairs provided access to the back door of the aircraft.  The kidnappers made sure the surviving passengers remain seated and would forget about the whole ordeal. Kidnapped humans got replaced by lookalike dummies, including things they had on them. They tried hard not to alter the timeline.


I am Really Struggling with this code Trying different ways to Convert JSON to HashMap but still no Progress any help regarding the code would be appreciated.I have tried Searching for the problem but it still Gives me other Exceptions like not a JsonObject and already tried a different lib but Google.gson works best for me please let me Know if you have any fix regarding this...      import java.util.HashMap;     import java.net.*;     import java.io.*;     import java.util.Map;      import com.google.gson.*;     import com.google.gson.reflect.*;      public class Weather {         private static Map<String, Object> jsonToMap(String str){             Map<String, Object> map = new Gson().fromJson(                     str, new TypeToken<HashMap<String, Object>>() {}.getType()             );             return map;         }          public static void main(String[] args){             String apiKey = "API not Provided";             String urlString = "http://api.openweathermap.org/data/2.5/forecast?id=1174872&APPID=" + apiKey + "&units=metric";             try{                 StringBuilder result = new StringBuilder();                 URL url = new URL(urlString);                 URLConnection connection = url.openConnection();                 BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));                 String line;                 while ((line = reader.readLine()) != null)                 {                     result.append(line);                 }                 reader.close();                 System.out.println("json print: ");                 System.out.println(result);                  Map<String, Object> respMap = jsonToMap(result.toString());                 Map<String, Object> mainMap = jsonToMap(respMap.get("main").toString());                 Map<String, Object> windMap = jsonToMap(respMap.get("wind").toString());                  System.out.println("Current Temperature: " + mainMap.get("temp"));                 System.out.println("Current Humidity: " + mainMap.get("humidity"));                 System.out.println("Current Wind : " + windMap.get("speed"));                 System.out.println("Current Wind Direction : " + windMap.get("deg"));              }catch(NullPointerException e){                 System.out.println("Null Pointer Exception Occurred!");             }catch (IOException e)             {                 System.out.println("Input Output Exception Occurred!");             }         }     }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Is there a way to find all the $0$s in $100!$? (Including zeroes that come between two non-zero numbers)  I know that to find the $0$s at the end we can use the greatest integer method. I was just curious if a method exists to find the remaining zeroes, too. (Of course without finding the actual value of $100!$ and counting, as is done in the only answer to this previous question: .)

One common math puzzle I've seen around asks for how many zeros are in the product of "100!"  Usually, the solution everyone gives goes something like try to match pairs of 5s and 2s that factor out of the numbers, which ends up being 24 zeroes (you can factor a 5 out of 20 of the numbers, and factor 2 5s out of 4 of the numbers; you can factor more than  24 2s out).   This however as far as I know gives the number of trailing zeroes at the end of the number, but does not account for the zeroes that are within the number. My question is, is this answer correct anyways? Can there be zeroes that aren't trailing that are inside? Why or why not and if there can be can we somehow figure out how many are within the product?   Thanks


I know it's a dumb question, but I really don't know it. I've thought of the derivative of y = x but it's still positive and the book says the answer is no.

We know that a function $f: [a,b] \to \mathbb{R}$ continuous on $[a,b]$ and differentiable on $(a,b)$, and if $f'>0 \mbox{ on} (a,b)$ , f is strictly increasing on $[a,b]$. Is there any counterexample that shows the converse fails?   I have been trying to come up with simple examples but they all involve functions that are discontinuous or has derivative $f'=0$ which does not agree with the hypothesis hmmm


Multiple articles online alludes to this tax penalty, claiming that dual income couple "can, often, may" suffer from it without giving any concrete sense of the magnitude.   Could we do an illustrative numerical example to figure this out?

If two individuals were considering marriage after college, what would the actual tax benefits be? Both are male. Both have full time jobs. In the United States.


I am using a book document class. I use \include{} to include a chapter. I checked the spec, it says for book class an extra empty page is added after every chapter. However, what I observe is the empty pages are inconsistent. i.e at for some chapter empty pages are added and for some they aren't.

As a documentclass I use book. Chapters always start on the right hand side.  How can I turn it off? I don't want to have empty pages. I don't care on which side starts  new chapter.


First time post. Basically after an wifi firmware update my laptop doesn't have WiFi anymore.   When I go to "Software & Updates" >> "Additional Drivers" it says device is not working with two options (which before i remember having about 4 options for this device) -"Do not use device" which is enabled -"Using oem-wifi-intel-iwlwifi-lp1757035-4.4-dkms driver in DKMS format wrapped by dkms-helper...(open source) When I try to select this it fails.  Dell precision 5520  Ubuntu 16.04 intel 8265/8275   Verified iwlwifi-8265-XX.ucode is located in /lib/firmware  rfkill list all > no soft or hard blocks on wifi, but soft block on bluetooth.  iwconfig > lo no wireless extensions  Please let me know what other information you need. Thanks!

i have trouble with internal wifi card on my Dell Latitude 5590 runing Ubuntu 16.04 LTS.  What happend before problem occured:   I recieved notification that my laptop has updates, updated it, enrolled MOK (as it begged) and everything worked fine. I decided to remove Code::Blocks, which resulted into  Restarted pc and Ubuntu lost embedded wifi adapter   sudo lshw -C Network shows    *-network UNCLAIMED             description: Network controller        product: Wireless 8265 / 8275        vendor: Intel Corporation   lspci -nn recognizes adapter  02:00.0 Network controller [0280]:   Corporation Wireless 8265 / 8275 [8086:24fd] (rev 78)   and rfkill list output is  0: dell-wifi: Wireless LAN     Soft blocked: no     Hard blocked: no 1: dell-bluetooth: Bluetooth     Soft blocked: yes     Hard blocked: no 2: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no   As far as i understood the problem is in oem-wifi-intel-iwlwifi-lp1757035-4.4-dkms-dkms, because then i try to reinstall it with sudo apt-get install --reinstall oem-wifi-intel*, it stops, signaling Bad return status for module build on kernel: 4.4.0-143-generic


I have just started using Mendeley with word and "I like it" is an understatement. So far, the most important BibDesk feature I'm using now is the ability to link the bibliographic entries with their actual order. And when I reorder the cite the link follows it around, too.  I know BibDesk is a good equivalent on Mac for TeXShop. What is a BibDesk equivalent for TexLive in Windows? I hope there is one that has at least almost the same features and also that feature I mentioned above.  (Very similar to  but a little different.)

I know that it is required to first create a database of references stored in a .bib file. Mendeley exports my reference list in .bib format. But how can I know what to write in curly brackets in \cite{} to refer to a particular author? Do I need to keep the .bib file open and find the relevant name to cite? Or am I missing something? What is your recommendation for referencing in LaTeX?


I have an existing working physical server serving up web pages and email. I need to point the DNS records to a new physical server for the web pages, leaving the email server as is.  I have my DNS records set up like the example below. Please note that I did not use mail for the hostname in MX records and all email clients use just the domain name in their setting for IMAP4 and SMTP and POP and I really do not want to reconfigure all of them.  How would I change these so the new web server will receive the web requests and the  existing mail server will keep running as is?  I am using dotyou.com to register my domain names and be the host for my DNS. This is the syntax they use in their DNS control panel and it is all that I am familiar  with.  I am using the domain name example.com instead of my real domain name for this example.  Edit host Files for domain (example.com)    Hostname  Address    Record type  MX Pref 1) www       1.2.3.4       A            10 2) @         1.2.3.4       A            10 3) @         example.com.  MX           5 4) www       example.com.  MX           7   Thanks!

I have a corporate website on a server that also hosts all our email. I have no idea how diligent all the employees have been about backing up their email / leaving old messages on the server, etc. In fact, I'd like to avoid all that hassle and keep the old email running on the old server.  I just want to move the website to a new, more reliable server, leaving the emails running on the old server.  How can I do this? When I point the DNS to the IP address of the new virtual host, once it propagates, will it cut off the email to the old server? The server admin of the old server seems to think so.  What's the solution here, operating on the principle that we want the LEAST amount of change / reconfiguration / data loss for our staff?


I am trying to create my first basic model and render post tutorials. I have created a model of a Coke can (other soft drinks are available) and added a quick texture I aquired off google images.  The problem is that for some reason the texture does not appear to cover the entire face. I think the issue is related to the subdivision modifier I am using as if I turn it off then the texture appears correctly.   Issue   Subdivision turned off   I have done some googling but cant find anything, can anyone help?

I'm not sure what's going on here. The unwrapped mesh doesn't extend the full length of the face down the side of the can. Is there any way to remap this using nodes?     Thanks guys


I had this question where it was given $a_n > 0$ and $\sum a_n$ convergent and I was to find out as well as prove that how does $$\sum a_n/r_n$$ behave where $$r_n = \sum_{m = n}^{\infty} a_m$$.   I attempted a method like this i think we can conclude from above given definition of $r_n$ that $r_n > r_{n + 1}$ and rewriting $a_n$ in $a_n/r_n$ as $(r_n - r_{n + 1})/r_n = 1 - \frac {r_{n + 1}}{r_n}$, now since this term is the general term of $\sum a_n/r_n$ and $$1 - \frac {r_{n + 1}}{r_n } \not= 0$$ so is it sufficient to conclude that $\sum a_n/r_n$ is divergent ?   I just couldn't assure myself completely with this method so I came here

Let $\displaystyle \sum a_n$ be  convergent series of positive terms and set  $\displaystyle b_n=\sum_{k=n}^{\infty}a_k$ , then prove that $\displaystyle\sum \frac{a_n}{b_n}$ diverges.   I could see that $\{b_n\}$ is monotonically decreasing sequence converging to $0$ and I can write $\displaystyle\sum \frac{a_n}{b_n}=\sum\frac{b_n-b_{n+1}}{b_n}$, how shall I proceed further?


Im making a small application where i can save user details using spring-boot. i created the entities and their corresponding repositories. When ever i make a post request to add a user the id of the user object which is null at the point of saving to the data base.This id is auto generated(Auto Increment) in MySQL. From the POST request i get 3 fields which are username,email,password. The User class contains fields id,username,email,password. I've added the annotations       @Id  @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id") private Integer id;   for the id field. an the constructors are  public User() { }  public User(String username, String email, String password) {     this.username = username;     this.email = email;     this.password = password; }   This is the error im getting.   The debugging process   my  userService class      @Service     public class UserService implements UserServiceInterface {          @Autowired(required = true)         private UserRepository userrepository;          @Override         public User CreateNewUser(User user) {             return userrepository.save(user);         } }   my userController class       @RestController     public class UserController {          UserService us = new UserService();          @RequestMapping(value ="/user",method = RequestMethod.POST)         public void RegisterUser(                            @RequestParam(value="username") String username,                 @RequestParam(value="email") String email,                 @RequestParam(value="password") String password){             us.CreateNewUser(new User(username,email,password));         } }   Any reason why i cant POST to save data to database? how to overcome this?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I want to position the text at the top of the box as it is declared, but when the column on the right contains a long text, it automatically changes to the bottom of the box :  There is my code :  \documentclass[12pt]{report}  %% Je suis francophone ! \usepackage[francais]{babel} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{fancybox} %% Je veux utiliser néanmoins des fontes qui « paraissent bien » en PDF \usepackage[cyr]{aeguill} \usepackage[table,svgnames]{xcolor} \newcolumntype{C}[1]{>{\centering\arraybackslash }b{#1}} \newcolumntype{L}[1]{>{\raggedright\arraybackslash }b{#1}} \newcolumntype{R}[1]{>{\raggedleft\arraybackslash }b{#1}} \begin{document} \begin{center} \begin{table}[h] \begin{tabular}{||C{0.5cm}||C{5cm}||C{4cm}||C{6.5cm}||}   \hline  \cellcolor{Gray} \textbf{RG} & \textbf{Définition} & \textbf{Mapping} & \textbf{Règles de gestion spécifiques}\\   \hline \hline   \multicolumn{1}{||L{0.5cm}|}{\parbox{0.5cm}{1}} & \multicolumn{1}{|L{5cm}|}{\footnotesize {Portail \-Date Traitement Courant}} & \multicolumn{1}{|L{4cm}|}{\scriptsize{RBP \_ vTBADMRBP \_ SUIVI \_ APPLI.D \_ TRAIT}} & \multicolumn{1}{|L{6.5cm}||}{\footnotesize {CASE WHEN [RBP \- Presentation View].[Dimension \- Référentiel Datamart].[L\_DATMR] = 'PORTAIL' THEN [RBP \- Presentation View].[Fait \- Suivi Application].[D\_TRAIT] END}} \\ \hline  \end{tabular} \caption{Équipe de travail} \end{table} \end{center}  \end{document}   There is a result that i have :

I want to position the text at the top of the box as it is declared, but when the column on the right contains a long text, it automatically changes to the bottom of the box     \documentclass[12pt]{report}  %% Je suis francophone ! \usepackage[francais]{babel} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{fancybox} %% Je veux utiliser néanmoins des fontes qui « paraissent bien » en PDF \usepackage[cyr]{aeguill} \usepackage[table,svgnames]{xcolor} \newcolumntype{C}[1]{>{\centering\arraybackslash }b{#1}} \newcolumntype{L}[1]{>{\raggedright\arraybackslash }b{#1}} \newcolumntype{R}[1]{>{\raggedleft\arraybackslash }b{#1}} \begin{document} \begin{center} \begin{table}[h] \begin{tabular}{||C{0.5cm}||C{5cm}||C{4cm}||C{6.5cm}||}   \hline  \cellcolor{Gray} \textbf{RG} & \textbf{Définition} & \textbf{Mapping} & \textbf{Règles de gestion spécifiques}\\   \hline \hline   \multicolumn{1}{||L{0.5cm}|}{\parbox{0.5cm}{1}} & \multicolumn{1}{|L{5cm}|}{\footnotesize {Portail \-Date Traitement Courant}} & \multicolumn{1}{|L{4cm}|}{\scriptsize{RBP \_ vTBADMRBP \_ SUIVI \_ APPLI.D \_ TRAIT}} & \multicolumn{1}{|L{6.5cm}||}{\footnotesize {CASE WHEN [RBP \- Presentation View].[Dimension \- Référentiel Datamart].[L\_DATMR] = 'PORTAIL' THEN [RBP \- Presentation View].[Fait \- Suivi Application].[D\_TRAIT] END}} \\ \hline  \end{tabular} \caption{Équipe de travail} \end{table} \end{center}  \end{document}