I am unable to connect to wifi.  I am not getting BROADBAND BCM in additional drivers.  When I run lspci -knn | grep Net -A2 I get the following error:   08:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723] DeviceName: Realtek RTL8723BE 802.11b/g/n 1x1Wi-Fi + BT4.0 Combo Adapter Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:804c] Kernel driver in use: rtl8723be Kernel modules: rtl8723be, wl   How can I fix it?


What are the infinities p and t in set theory ??

Im a beginner in (infinite) set theory, So keep that in mind. I know cantor's diagonal, cantors pairing function , the ZFC axioms and basic stuff like that.  Im very intrested in infinite sets and in particular cardinality and the continuüm hypothesis.  Now I read an article ( see link ) where They mention that - If I understand correctly - that two types of cardinality are equal : card(p) = card(t).  Im not sure If $p$ and $t$ are the standard notation for these sets / Cardinals / ordinals.  But the article says who worked on it , So I hope you guys can explain $p$ and $t$ to a beginner like me.  It is Said - I think - that $p$ and $t$ are candidates to break CH.  In case the article goes away here is a quote :    INFINITY  Mathematicians Measure Infinities and Find They’re Equal By KEVIN HARTNETT September 12, 2017  Two mathematicians have proved that two different infinities are equal in size, settling a long-standing question. Their proof rests on a surprising link between the sizes of infinities and the complexity of mathematical theories. 70  Colors Collective for Quanta Magazine In a breakthrough that disproves decades of conventional wisdom, two mathematicians have shown that two different variants of infinity are actually the same size. The advance touches on one of the most famous and intractable problems in mathematics: whether there exist infinities between the infinite size of the natural numbers and the larger infinite size of the real numbers.  The problem was first identified over a century ago. At the time, mathematicians knew that “the real numbers are bigger than the natural numbers, but not how much bigger. Is it the next biggest size, or is there a size in between?” said Maryanthe Malliaris of the University of Chicago, co-author of the new work along with Saharon Shelah of the Hebrew University of Jerusalem and Rutgers University.  In their new work, Malliaris and Shelah resolve a related 70-year-old question about whether one infinity (call it p) is smaller than another infinity (call it t). They proved the two are in fact equal, much to the surprise of mathematicians.  “It was certainly my opinion, and the general opinion, that p should be less than t,” Shelah said.    Here is the article    So What is this all about ?  I looked on arxiv but I was not sure If there was a connection.  Also quantamagazine says it is a big result , but I have not heard anyone mention it ??  Now that $p = t$ I wonder If They are both countable or both uncountable ... or still candidates to break CH ??


regex that matches everything except a constant

I need a regexp that will match everything except a single constant (case ignored)  Example for constant ALL, should match words like: dog, MOUSE, mall, alligator. But it shouldn't match: all, ALL, alL.


Cauchy's integral formula "type" integral

Let $\Gamma$ denote the positively oriented circle of radius $2$ with center at the origin. Let $f$ be an analytic function on $\{z\in\mathbb{C}:|z|>1\}$, and let $$\lim_{z\to\infty} f(z)=0.$$  Prove that  $$f(z)=\dfrac{1}{2\pi i}\int_{\Gamma}\dfrac{f(\zeta)}{z-\zeta}d\zeta$$,  for all $z\in\mathbb{C}$ with $|z|>2$.  I am quite bad at complex analysis and I would appreciate any hints/directions here. Also, if there are generic methods to attack such problems, please share them as well.  Thanks in advance!


How to use a continuity test to differentiate between wires?

I'm trying to repair my headphones with a broken jack. I just purchased a replacement TRRS jack, and now my problem is knowing the function of the five different wires in my earbuds. How can I use a multimeter to do this? Thank you in advance.


How to dual boot windows 7 with Ubuntu installed first?

i'm running ubuntu 15.04, but i want to play  some games like battlefield 2 or command and conquer generals, but i don't think that's possible on ubuntu (or using a windows on virtual machine).  So please guys, how to i install windows 7 dual boot with ubuntu install first, if it has something to do with partitioning please more details because i'm new to this os, the partitioning here seems nothing like windows,thanks in advance :p


How to select a node with a given attribute value in C#?

I just want to select the target element which has "name" attribute value = 'syslog'. Anyway, I always get an NullReferenceException. Can anyone help me to figure out what is the problem?   ---------------- My code -------------------------------------------  XmlNode root = _configFile.DocumentElement; // root is not none, and is correct. XmlNode syslogNode = root.SelectSingleNode("descendant::targets/target[@name='syslog']"); // the syslogNode is null   -----------------My XML file --------------------------------------  <nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">    <extensions>     <add assembly="NLog.Targets.Syslog" />   </extensions>    <targets>     <target name="syslog" xsi:type="Syslog" syslogserver="127.0.0.1" port="514" facility="Local7" />     <target name="file" xsi:type="File" layout="${level} | ${longdate} | ${callsite:className=true:fileName=false:includeSourcePath=false:methodName=true} | ${message} ${exception:format=tostring}"             fileName="${specialfolder:folder=LocalApplicationData}/Televic Conference/CoCon/Log/server_log_${shortdate}.txt"             archiveFileName="${specialfolder:folder=LocalApplicationData}/Televic Conference/CoCon/Log/Archives/server_log.{#}.txt"             archiveEvery="Day" archiveNumbering="Rolling" maxArchiveFiles="20" concurrentWrites="true" keepFileOpen="false"/>     <target name="console" xsi:type="ColoredConsole" layout="${longdate}: ${message}"/>     <target name="debug" xsi:type="OutputDebugString" layout="${longdate}: ${message}"/>   </targets>    <rules>     <logger name="*" minLevel="Trace" appendTo="syslog"/>     <logger name="*" minlevel="Trace" writeTo="file" />   </rules> </nlog>


The description written in the FAQ reads:      Voted on 600 questions and 25% or more of total votes are on questions   I voted 671 times on Stackoverflow, and more than 30% of my votes are on questions; the rest would be on answers.  But still there is no "Electorate" badge.


Phrase for a small, legitimate fix for part of a system so broken the fix is unimportant

Looking for a phrase/metaphor describing a situation where a proposed solution, though valid, is targeted for one of many problems in an entity plagued by so many problems as to render the individual solution unimportant. An example would be discussing improving the energy efficiency in the kitchen of a building that is condemned or on the verge of falling apart; though the methods for improving the kitchen might be totally valid, they're of little practical concern as they'd make no contribution to the long term viability of the building.  Something like "a drop in the bucket" but which emphasizes that the "drop" is well-conceived or -intentioned.    EDIT:  The answers here have been fantastic (and hilarious), though I think the phrase that best fits my request was actually listed by @user9383 in  (not in the answer but in the question itself):     Fixing a leaky faucet in a burning building.   This phrase perfectly captures both aspects of my request:   The intentions/method have merit: in general, leaky faucets need to be fixed. Despite this, the effort is wasted due much bigger problems: despite the inherent merit of the faucet-fixing, the ensuing destruction prevents the realization of any substantial benefit.


This question would be well-suited to both SO and Webmasters. (Maybe better suited just to Webmasters, but there is enough traffic about reducing HTML load latency on SO that I would like an excellent question / answer here that can help stave off duplicates. :)  I think it'd be super if there was some way to symlink / hardlink this question and answer between the two sites: it would bring a larger audience to bear on editing it, and it would have only a single copy to maintain for those who would like it to be in sync on both.  So: is there any mechanism for symlinking / hardlinking / linking questions on multiple SE sites? If not, is there enough reason to build one?  Thanks!


Does Confusion cast via the Dreadful Word invocation count as a warlock spell?

From the answers over on the question of "", the implication is that something is a 'class spell' if it is on that class' spell list.  There is not, so far as I'm aware, any other general criteria for what makes something considered a warlock/wizard/etc. spell.   I am also under the impression that spending a warlock spell slot does not automatically make that spell a warlock spell, given the multiclassing rules allowing sorcerer/etc. spells to be cast via warlock spell slots.   While the rules state "To cast one of your warlock spells of 1st level or higher, you must expend a spell slot," and "The Warlock table shows how many spell slots you have to cast your warlock spells [...]", the phrasing of Dreadful Word could also be parsed as an instance of "specific beats general" enabling a non-warlock spell to be cast via warlock spell slots regardless of those rules (it is already enabling you to cast a spell you don't know, after all).  The multiclassing rules also give me the impression that spending a spell slot from a specific class- say, warlock- doesn't mean that the resulting spell is a warlock spell, anyways; you can cast sorcerer spells with pact magic slots, for example, and they still count as sorcerer spells.  So, the question: with a literal reading of the rules, since confusion is not on the warlock spell list, is confusion a warlock spell when cast via Dreadful Word for the purposes of Rod of the Pact Keeper?   I care about specifically a literal reading because it seems extremely clear that it should count as a warlock spell- there's no implication of what DC to use if you're not meant to use your warlock spell save DC ("Charisma is your spellcasting ability for your warlock spells"), for example. Crawford also - thanks, @Bloodcinder. I would never intend to argue otherwise in actual play. I'm just curious what the literal interpretation of the rules in this case results in, even if there truly is no rule indicating that it would be considered a warlock spell and it not being one seems nonsensical.


Display element as preformatted text via CSS

Is there any way to emulate the display of a pre element via CSS?  For example, can I keep the whitespace intact in this div by using a CSS rule?  <div class="preformatted">    Please procure the following items:      - Soup     - Jam     - Hyphens      - Cantaloupe </div>


Why don't we define potential due to a magnetic field?

We define electric potential and gravitational potential and use them quite often to solve problems and explain stuff. But I have never encountered magnetic potential, neither during my study (I am a high-schooler), nor during any discussion on physics.  So, does magnetic potential even exist? According to me, it should because a magnetic field is a conservative one and so we can associate a potential with it? Also if it's defined, then why don't we encounter it as often as we do the others (electric potential, gravitational potential, etc.)?  I have encountered magnetic potential energy only in the cases where a dipole is subjected to a magnetic field. Is magnetic potential limited only to this scenario, or is there a general expression for the magnetic potential?    I should have said this earlier, but don't restrain your answers due to my scope. You can use vector calculus as I am quite familiar with it. Also, this question is meant for everyone, so even the answers which are out of my scope are appreciated.


Is it true that if $f$ is surjective from $A$ to $B$ then there is an injective function $g$ from $B$ to $A$?

I think the answer is yes because otherwise $f$ wouldn't be a function. Is this correct? And how would the formal proof go?


Fails to send email with smtpClient in port 465

I'm using SmtpClient to send email. But when I use it with Port 465 it fails. It works with the following ports: 587 & 25. I read that ports 25 and 587 are for TLS, while port 465 for SSL.  Im using enableSSL as true, and I'm sending from gmail to gmail account.


I am using ubuntu 14.04 , While trying to install the scanner canon Lide220 using the command sudo apt-get install xsane the following message appears:  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   What can I do to succesfully install it?


administrative passwd how to change it in the root

each time i go to the root and try to change my passwd an error occurs and it says authencation manipulation error or some thing like that.and btw the passwd s match. whoever knows whats happening please help.HOw DO I CHANGE MY PASSWD .


"off colour" and "out of sorts" in British English

I am wondering whether "off colour" and "out of sorts" are completely interchangeable idioms in British English, and if not, what the difference is.     John {looks/feels} a bit {off colour/out of sorts} today.   An Australian co-worker of mine told me it could mean "upset", but I find his explanation contrary to dictionary definition.


Let $A$ be the complex $3 × 3$ matrix  $A = \begin{bmatrix}2&0&0 \\ x&2 & 0 \\y&z&-1\end{bmatrix}$  Find all triples $(x, y, z)$ for which the characteristic and minimal polynomials of $A $ are different.  My attempts : the Characteristic polynomial of $A  = (\lambda +1)(\lambda -2)^2$  Case $1$:  if  $x=y= z \neq 0$ ,then minimial polynomial of   $A  = (\lambda +1)(\lambda -2)^2$  Case $2$ : if $x=y= z =0$,then minimial polynomial of   $A  = (\lambda +1)(\lambda -2)$  Here  im confused that how  can i find  all triples $(x, y, z)$ for which the characteristic and minimal polynomials of $A $ are different.


How can I auto hide alert box after it showing it?

All I want to do is, how can I auto hide alert box within specific seconds after showing it?  All I know is,   setTimeout(function() {        alert('close');  }, 5000);  // This will appear alert after 5 seconds   No need for this I want to disappear alert after showing it within seconds.  Needed scenario :   Show alert Hide/terminate alert within 2 seconds


Any IDE's in Ubuntu for Windows Development with C Sharp?

I'm wondering if you folks could steer me toward some Window's Dev IDE tools for ASP.Net and or C Sharp?  Is there a good site for finding IDE's for Ubuntu? I've not totally installed yet, just looked at it and have been impressed running of DVD in my DVD Drive.


sed regular expression behaving differently than in vim and perl?

Here's a sample 'test.txt'  abcdX1yad45das abcdX2fad45das abcdX3had45das abcdX4wad45das abcdX5mad45das   sample desired output:  X1yad X2fad X3had X4wad X5mad   I could get it working in vim with:  :% s/\v.*(X\d)(.*)45.*/\1\2/   and worked in perl as well with:  open(my $file, "<", "test.txt"); while(<$file>) {     s/.*(X\d)(.*)45.*/$1$2/;      print $_; }   my eventual regular expression needs two groupings, it wasn't required for this example output  am not able to get it work with sed:  sed -r 's/.*(X\d)(.*)45.*/\1\2/' test.txt abcdX1yad45das abcdX2fad45das abcdX3had45das abcdX4wad45das abcdX5mad45das   just to check sed is working,  sed -r 's/(a)/#\1#/' test.txt #a#bcdX1yad45das #a#bcdX2fad45das #a#bcdX3had45das #a#bcdX4wad45das #a#bcdX5mad45das   what am I doing wrong in sed?


How to prove that $\{f+g<a\}=\bigcup_{r\in{\Bbb Q}}(\{f<r\}\cap\{g<a-r\})$?

Let $(X,{\mathcal A})$ be a measurable space, and $f,g:X\to{\Bbb R}$ be measurable functions. It is a standard trick to use the following set equality to show that $f+g$ is also measurable.  $$\{f+g<a\}=\bigcup_{r\in{\Bbb Q}}(\{f<r\}\cap\{g<a-r\})\quad\text{for any}\quad a\in{\Bbb R}$$ where $\{f<a\}:=\{x\in X:f(x)<a\}$. One direction is easy: $$\{f+g<a\}\supset \bigcup_{r\in{\Bbb Q}}(\{f<r\}\cap\{g<a-r\})\quad\text{for any}\quad a\in{\Bbb R}.$$  Here are my questions:     How can one prove that $$\{f+g<a\}\subset \bigcup_{r\in{\Bbb  Q}}(\{f<r\}\cap\{g<a-r\})\quad\text{for any}\quad a\in{\Bbb R}?$$   Is there a counterexample of the following claim?   $$\{fg<a\}= \bigcup_{r\in{\Bbb  Q}\setminus\{0\}}(\{f<r\}\cap\{g<\frac{a}{r}\})\quad\text{for any}\quad a\in{\Bbb R}?$$


Iran Visa Issue: U.S. - Mexico Dual National Residing in EU

Several months ago I tried going to Iran with my American passport to attend a marathon but got denied. The embassy or company didn't give me any direct reason as to why but shortly afterwards the marathon's date was moved (which I suspect was the reason I was denied). I plan on trying to go again using my Mexican passport by using the Visa on Arrival but my circumstances will be a bit different.   For the next few years I will live & work in the EU. My residence permit will be based on my American passport since I didn't get my other one until after submitting my EU paperwork. I assume I will need to use my former passport to exit/enter the EU but want to use the latter to enter Iran. The biggest problem I foresee would be arriving at IKIA from an EU flight without entry/exit stamps from the country I'm arriving. What issues could this cause, if any?   I understand how to travel with multiple passports but haven't seen anyone post or comment about a similar situation of having dual citizenship but residing in a third country and wanting to travel to a fourth one in which one citizenship might cause issues. The closest I've found are below:


I'm new to shell scripting. I'd like to know if there's a command similar to "echo" for displaying text in a terminal, but instead of simply displaying it immediately, it actually types it, like if someone was actually typing on the terminal?   I'd also appreciate it if someone could point me to pages explaining simple scripting like menus and such.


Does it matter what I choose for serialVersionUID when extending Serializable classes in Java?

I'm extending a class (ArrayBlockingQueue) that implements the . Sun's documentation (and my IDE) advises me that I should set this value in order to prevent mischief:     However, it is strongly recommended that all serializable classes explicitly declare serialVersionUID values, since the default serialVersionUID computation is highly sensitive to class details that may vary depending on compiler implementations, and can thus result in unexpected InvalidClassExceptions during deserialization.   Now, I couldn't care less about what value to put in there. Does it matter?


What is the sum $\sum_{k=0}^{n}k^2\binom{n}{k}$?

What should be the strategy to find  $$\sum_{k=0}^{n}k^2\binom{n}{k}$$  Can this be done by making a series of $x$ and integrating?


Proving a trig identity: $\frac{\sin(A + B)}{\sin(A - B)}=\frac{\tan A + \tan B}{\tan A - \tan B}$

I'm learning about trig identities, and I'm struggling to prove that two expressions are equal:  $$ \frac{\sin(A + B)}{\sin(A - B)}=\frac{\tan A + \tan B}{\tan A - \tan B} $$  How do you go about proving this? I know about compound angles - i.e. the sine, cosine and tangent of $(A \pm B)$, but don't know how to apply it in this situation.


Why does Covariance measure only Linear dependence?

1) What is meant by linear dependence?  2) How can I convince myself that covariance measures linear dependence?   3) How I can convince myself that non-linear dependence is not measured by covariance?


sending email using python after checking some condition

I am trying to build a prototype in python. The used case is fairly simple. Upon running the program will accept an input x and will execute something like  if(x<=3){   send email to xxx@gmail.com   some html copy }    This is the start...Now I think I would need a web server to send an email. And that's where I getting lost. Can I avoid installing a server stack for this task? I am pretty new to python.


Show that two consistent systems are equivalent to each other

$A: n \times n$, $B: n \times m$ and $A$ is   invertible.      Show that "$\forall \vec{b} \in \mathbb{R}^n, B \vec{x} = \vec{b}$ is   consistent" is equivalent to "$\forall \vec{b} \in \mathbb{R}^n, (AB)  \vec{x} = \vec{b}$ is consistent."   I know that $(AB)\vec{x}=\vec{b}$ can be written as $B\vec{x}=A^{-1}\vec{b}$ since we know that $A$ is invertible. The form $B\vec{x}=A^{-1}\vec{b}$ then allows us to equate the first and second expressions so that $\vec{b} = A^{-1}\vec{b}$. This means that $A^{-1} = I_n$ so that $A = I_n$ as well (since $A^{-1}(AB)\vec{x}=A^{-1}\vec{b} \Rightarrow B\vec{x} = A^{-1}\vec{b}$, and $BI_n = B$). So the expression $B\vec{x}=\vec{b} \equiv (AB)\vec{x}=\vec{b}$.  Can someone help me check my work or tell me where I've gone wrong here?


Can actual quantum effects occur on a macro scale?

I apologize if this question is posted on the wrong portion of the website, but I knew no better place to ask.  I've come to see that some effects, such as super-conduction may happen at either extremely low temperatures, or at extreme temperatures (the recent discovery of superconducting iron in the bowels of the earth, for one), and this is fascinating.  My question is: can (does?) the same principle be applied to quantum effects? Would it be applicable to, for example, say that although quantum effects happen at nano scales and below they may happen on a grand scale of say, the entire Universe (as a solitary unit)?  Can said quantum effects happen at moments of say, picoseconds after the Big Bang due to the turbulence of forces involves in such an event? Or even within the core of a dying star?  Thank you for any answers or clarification of my misinformation.


I have this code:  import re  s = """line1    line2"""  print(re.sub("^", "=", s, re.M))   and output is:  =line1    line2   i.e. reg. expression "^" finds begin of string only, not begin of lines as said in documentation. I do realize the error is in my code but where?   Genneraly I need to replace all the leading spaces of each line in the string.  Thank you!


How to safely replace a not-yet-failed disk in a Linux RAID5 array?

I have a software RAID5 array (Linux md) on 4 disks.   I would like to replace one of the disks with a new one, without putting the array in a degraded state, and if possible, online. How would that be possible?   It's important because I don't wan't to:    take the risk of stressing the other disks so one may crash during rebuild,  take the risk of being in a "no-parity state" so I don't have a safety net for some time.    I suppose doing so online is too much asking and I should just raw copy (dd) the data of the old disk to the new one offline and then replace it, but I think it is theoretically possible...   Some context: Those disks have all been spinning almost continuously for more than 5.5 years. They still work perfectly for the moment and they all pass the (long) SMART self-test. However, I have reasons to think that one of those 4 disks will not last much longer (supposed predictive failure).


How do I create a partially transparent flag?

I'm making an animation with a flag, and I was wondering if anyone knows how to create like a transparent fabric material?   The flag looks a bit dull, and doesn't look realistic at all. After some references I noticed that flags are a bit transparent, seeing as they are woven.  Reference :    I need to make this flag have the same type of material  If you can tell me how to make it look like fabric and not like rubber, I'd be very thankful.  P.S: If anybody knows how to make little "ripples", please comment and let me know.


If $\frac{a^{2}-1}{b+1}+\frac{b^{2}-1}{a+1}$ is an integer, prove that also $\frac{a^{2}-1}{b+1}$ and $\frac{b^{2}-1}{a+1}$ are integers. By doing the math, I get $\frac{(a-1)(a+1)^{2}+(b-1)(b+1)^{2}}{(a+1)(b+1)}$ is an integer which means that $(a+1)(b+1)$ divides $(a-1)(a+1)^{2}+(b-1)(b+1)^{2}$. but I don't know how to continue. By the way, this is not homework or anything. I just found it in a book.


Another way to prove that all its members of a sequence are positive integers without using matrix.

Let's be sequence $ (u_n) $  is defined by $u_1=1$, $u_{n+1} =2 u_n+\sqrt{3 u_n^2+6}, \quad \forall n \geq 1.$ Prove that all its members are positive integers.   I tried by using matrix.      Put  $ v_n = \sqrt{3 u_n^2+6} $, then $ v_n^2 - 3u_n^2 = 6 $ and     $$ u_{n+1}=2u_n + v_n, \quad \forall n \geq 1. $$     We have \begin{align*} v_{n+1}^2 &= 3u_{n+1}^2 + 6\\ &= 3(2u_n + v_n)^2 +v_n^2 - 3u_n^2\\ &= 9u_n^2 + 12 u_n v_n + 4v_n^2\\ &= (3u_n + 2 v_n)^2\\ \end{align*} Then, $ v_{n+1} = 3u_n + 2 v_n. $ We have $$ \left( \begin{array}{c} u_1  \\ v_1 \\ \end{array}\right)  = \left( \begin{array}{c} 1  \\ 3 \\ \end{array}\right), \quad \left( \begin{array}{c} u_{n+1}  \\ v_{n+1} \\ \end{array}\right)  = \left( \begin{array}{cc} 2& 1  \\ 3 &2 \\ \end{array}\right)\left( \begin{array}{c} u_n  \\ v_n \\ \end{array}\right)$$  Thus all the numbers $u_ n$ and $v_ n , n ≥ 2,$ are positive integers.  How can I solve this prolbem without using matrix?


Normality of dependent variable = normality of residuals?

This issue seems to rear its ugly head all the time, and I'm trying to decapitate it for my own understanding of statistics (and sanity!).   The assumptions of general linear models (t-test, ANOVA, regression etc.) include the "assumption of normality", but I have found this is rarely described clearly.   I often come across statistics textbooks / manuals / etc. simply stating that the "assumption of normality" applies to each group (i.e., categorical X variables), and we should we examining departures from normality for each group.   Questions:     does the assumption refer to the values of Y or the residuals of Y?  for a particular group, is it possible to have a strongly non-normal distribution of Y values (e.g., skewed) BUT an approximately (or at least more normal) distribution of residuals of Y?   Other sources describe that the assumption pertains to the residuals of the model (in cases where there are groups, e.g. t-tests / ANOVA), and we should be examining departures of normality of these residuals (i.e., only one Q-Q plot/test to run).  does normality of residuals for the model imply normality of residuals for the groups? In other words, should we just examine the model residuals (contrary to instructions in many texts)?  To put this in a context, consider this hypothetical example:   I want to compare tree height (Y) between two populations (X).   In one population the distribution of Y is strongly right-skewed (i.e., most trees short, very few tall), while the other is virtually normal  Height is higher overall in the normally distributed population (suggesting there may be a 'real' difference). Transformation of the data does not substantially improve the distribution of the first    population.  Firstly, is it valid to compare the groups given the radically different height distributions? How do I approach the "assumption of normality" here? Recall height in one population is not normally distributed. Do I examine residuals for both populations separately OR residuals for the model (t-test)?     Please refer to questions by number in replies, experience has shown me people get lost or sidetracked easily (especially me!). Keep in mind I am not a statistician; though I have a reasonably conceptual (i.e., not technical!) understanding of statistics.  P.S., I have searched the archives and read the following threads which have not cemented my understanding:


Add voting buttons to the tag synonym overview page

If you look at the  and want to vote for a tag synonym (or just see its current vote count), you have to click through to the tags page and then to the info tab.  It would be much more convenient if the voting buttons were right there on the overview page, so that proposed synonyms can be voted on in-place.  Alternatively, if this takes too much server resources, it would be an improvement to have a link on pending synonyms that leads directly to the info-tab for that tag.


Proving that a function is not totally differentiable in $(0,0)$

I am trying to show that $g(x,y)=y f(x,y)$ with  $$f: \mathbb R^2 \rightarrow \mathbb R $$ $$ f(x,y) =  \begin{cases} \dfrac {2xy^2}{x^2+y^4} & (x,y)\ne (0,0) \\\\    0 & (x,y)=(0,0)  ~ \end{cases} $$  is not totally differentiable in $(0,0)$.   What I already have found out about the functions is that $f$ is not continuous in $(0,0)$, the function $g$ has all directional derivatives and they are equal to $0$.  The criterion I use for total differentials is that $f$ is totally differentiable in $x$, if there exists a linear map $L$ such that  $$\lim_{h \to 0}\frac{g(x+h)-g(x)-Lh}{|h|}=0$$  For $(x,y)=(0,0)$ we get  $$\lim_{h \to 0}\frac{g(h)-g(0)-Lh}{|h|}=\lim_{h \to 0}\frac{h_2f(h)-0f(0)-Lh}{|h|}=\lim_{h \to 0}h_2\frac{f(h)-f(0)}{|h|}-\frac{Lh}{|h|}=0 $$  Is it legitimate to deduce from that that $g$ is not totally differentiable in $(0,0)$ because $$lim_{h \to 0}\frac{f(h)-f(0)}{|h|}$$ does not exist, as $f$ is not continous in $(0,0)$?


Intermediate fields of a finite field extension that is not separable

Let $\mathbb{F}_p$ be the finite field with $p$ elements, where $p$ is a prime number. Let $x$ and $y$ be transcendental and algebraically independent over $\mathbb{F}_p$. The extension $\mathbb{F}_p(x,y)/\mathbb{F}_p(x^p,y^p)$ is finite of degree $p^2$. To see this consider the polynomials $T^p-x^p$  and $T^p-y^p\in\mathbb{F}_p(x^p,y^p)[T]$.  So, if $K$ is any (proper) intermediate field of this extension, we must have $[K:\mathbb{F}_p(x^p,y^p)]=p$. For each prime $q\neq p$, consider the polynomial $T^p-x^{qp}\in\mathbb{F}_p(x^p,y^p)[T]$. It is an irreducible polynomial of degree $p$ with $x^q$ as root. So the extension $\mathbb{F}_p(x^p,y^p)(x^q)/\mathbb{F}_p(x^p,y^p)$ has degree $p$ and hence, $\mathbb{F}_p(x^p,y^p)(x^q)$ is a proper intermediate field of the original extension. Note that we can do the same with $y$ instead of $x$. Since there are infinite primes $\neq p$, there will be infinite (proper) intermediate fields of the original extension. These fields are distinct, because they are obtained by adjoining a root of an irreducible polynomial, and their irreducible polynomials are distinct.  This shows that $\mathbb{F}_p(x,y)/\mathbb{F}_p(x^p,y^p)$ is finite but not simple, hence, it is not separable.      My question is: are there other intermediate fields other than that pointed out previously?   I first tried to show that $\mathbb{F}_p(x,y)/\mathbb{F}_p(x^p,y^p)$ is not simple by supposing the existence of a primitive element then trying to get a contradiction, specifically, that $x$ and $y$ are algebraically dependent. The problem is, they are algebraically dependent over $\mathbb{F}_p(x^p,y^p)$, because they vanish this (non-zero) polynomial $T_1^p-x^p+T_2^p-y^p\in\mathbb{F}_p(x^p,y^p)[T_1,T_2]$. If you know someway of proving that $\mathbb{F}_p(x,y)/\mathbb{F}_p(x^p,y^p)$ is not simple by contradiction, please answer it too.


Trying to render an image under a problem

I'm trying to add an image to a problem but it is not rendering the way I want it to. Below is the TeX code and below that a screenshot of what is happening.    \documentclass[]{book}  %These tell TeX which packages to use. \usepackage{array,epsfig} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsxtra} \usepackage{amsthm} \usepackage{mathrsfs} \usepackage{color} \usepackage{graphicx}  %Here I define some theorem styles and shortcut commands for symbols I use often \theoremstyle{definition} \newtheorem{defn}{Definition} \newtheorem{thm}{Theorem} \newtheorem{cor}{Corollary} \newtheorem*{rmk}{Remark} \newtheorem{lem}{Lemma} \newtheorem*{joke}{Joke} \newtheorem{ex}{Example} \newtheorem*{soln}{Solution} \newtheorem{prop}{Proposition}  \newcommand{\lra}{\longrightarrow} \newcommand{\ra}{\rightarrow} \newcommand{\surj}{\twoheadrightarrow} \newcommand{\graph}{\mathrm{graph}} \newcommand{\bb}[1]{\mathbb{#1}} \newcommand{\Z}{\bb{Z}} \newcommand{\Q}{\bb{Q}} \newcommand{\R}{\bb{R}} \newcommand{\C}{\bb{C}} \newcommand{\N}{\bb{N}} \newcommand{\M}{\mathbf{M}} \newcommand{\m}{\mathbf{m}} \newcommand{\MM}{\mathscr{M}} \newcommand{\HH}{\mathscr{H}} \newcommand{\Om}{\Omega} \newcommand{\Ho}{\in\HH(\Om)} \newcommand{\bd}{\partial} \newcommand{\del}{\partial} \newcommand{\bardel}{\overline\partial} \newcommand{\textdf}[1]{\textbf{\textsf{#1}}\index{#1}} \newcommand{\img}{\mathrm{img}} \newcommand{\ip}[2]{\left\langle{#1},{#2}\right\rangle} \newcommand{\inter}[1]{\mathrm{int}{#1}} \newcommand{\exter}[1]{\mathrm{ext}{#1}} \newcommand{\cl}[1]{\mathrm{cl}{#1}} \newcommand{\ds}{\displaystyle} \newcommand{\vol}{\mathrm{vol}} \newcommand{\cnt}{\mathrm{ct}} \newcommand{\osc}{\mathrm{osc}} \newcommand{\LL}{\mathbf{L}} \newcommand{\UU}{\mathbf{U}} \newcommand{\support}{\mathrm{support}} \newcommand{\AND}{\;\wedge\;} \newcommand{\OR}{\;\vee\;} \newcommand{\Oset}{\varnothing} \newcommand{\st}{\ni} \newcommand{\wh}{\widehat}  %Pagination stuff. \setlength{\topmargin}{-.3 in} \setlength{\oddsidemargin}{0in} \setlength{\evensidemargin}{0in} \setlength{\textheight}{9.in} \setlength{\textwidth}{6.5in} \pagestyle{empty}  \begin{document}  Show the following regions in the complex plane and determine if the the regions are (i) open, (ii) closed, (iii) neither open nor closed.  \begin{enumerate}      \item $2<|z|$      \begin{soln}     \begin{figure}[hbt!]        \centering     \includegraphics[width=.4\textwidth]{abs(z) bigger than 2.PNG}         \end{figure}     \end{soln}      \item $Re(z)\ge 2$      \begin{soln}     \begin{figure}[hbt!]        \centering     \includegraphics[width=.4\textwidth]{Re(z) bigger than 2.PNG}         \end{figure}     \end{soln}  \end{enumerate}  \end{document}   Here is the image of the compiled PDF.    Why is the image that is coded under the problem and the solution showing up at the bottom of the page for both images? How do I fix this?


The continuity of the derivative of a differentiable function

Let $f:[a, b] \rightarrow \mathbb{R}$ be a function that is differentiable everywhere. What can we say about the continuity of $f^{(1)}$? The only results that is related to this I that I can find is that if $f^{(1)}(a) < \lambda < f^{(1)}(b)$, then there is $x\in (a,b)$ s.t. $f(x) = \lambda$ and so $f^{(1)}$ may not have any discontinuities of the first kind.   An example of a function that has a derivative that is discontinuous is $f(x) = x^{2}\sin(\frac{1}{x})$ $ \text{for } x\neq{0}$ and $f(x)=0$ if $x=0$ which has a derivative that has a discontinuity of the second kind at $0$.   I'm not sure how to use this example to create other examples, say $f^{(1)}$ is discontinuous on a: dense subset of $[a,b]$, on a subset of measure $\frac{b-a}{2}$, etc.  Also what happens if we replace " differentiable everywhere" by "differentiable a.e."?


An ability to make my CAPS work as CTRL again

When are you going to recover the ability to make CAPS work like Ctrl. Like in all previous versions?   This is really critical as I am using emacs key-bindings and this is a one huge stopper and forces me to drop Ubuntu, at least until I see it fixed.


Puppin.org seems to be scraping SO content

news.puppin.org seems to be scraping right into a wordpress blog, and ranking in searches too. I ran across this link:  http://news.puppin.org/question/non-relational-db-which-one-is-the-right-choice-closed/


The following expression enables snapping for PyQGIS 2.0 :  QgsProject.instance().setSnapSettingsForLayer(layer.id(), True, 2, 1, 10, True)   What is the equivalent expression in PyQGIS 3.0?


KL divergence between two univariate Gaussians

I need to determine the KL-divergence between two Gaussians. I am comparing my results to , but I can't reproduce their result. My result is obviously wrong, because the KL is not 0 for KL(p, p).  I wonder where I am doing a mistake and ask if anyone can spot it.  Let $p(x) = N(\mu_1, \sigma_1)$ and $q(x) = N(\mu_2, \sigma_2)$. From Bishop's PRML I know that  $$KL(p, q) = - \int p(x) \log q(x) dx + \int p(x) \log p(x) dx$$  where integration is done over all real line, and that  $$\int p(x) \log p(x) dx = -\frac{1}{2} (1 + \log 2 \pi \sigma_1^2),$$  so I restrict myself to $\int p(x) \log q(x) dx$, which I can write out as  $$-\int p(x) \log \frac{1}{(2 \pi \sigma_2^2)^{(1/2)}} e^{-\frac{(x-\mu_2)^2}{2 \sigma_2^2}} dx,$$  which can be separated into  $$\frac{1}{2} \log (2 \pi \sigma_2^2) - \int p(x) \log e^{-\frac{(x-\mu_2)^2}{2 \sigma_2^2}} dx.$$  Taking the log I get  $$\frac{1}{2} \log (2 \pi \sigma_2^2) - \int p(x) \bigg(-\frac{(x-\mu_2)^2}{2 \sigma_2^2} \bigg) dx,$$  where I separate the sums and get $\sigma_2^2$ out of the integral.  $$\frac{1}{2} \log (2 \pi \sigma^2_2) + \frac{\int p(x) x^2 dx - \int p(x) 2x\mu_2 dx + \int p(x) \mu_2^2 dx}{2 \sigma_2^2}$$  Letting $\langle \rangle$ denote the expectation operator under $p$, I can rewrite this as  $$\frac{1}{2} \log (2 \pi \sigma_2^2) + \frac{\langle x^2 \rangle - 2 \langle x \rangle \mu_2 + \mu_2^2}{2 \sigma_2^2}.$$  We know that $var(x) = \langle x^2 \rangle - \langle x \rangle ^2$. Thus   $$\langle x^2 \rangle = \sigma_1^2 + \mu_1^2$$  and therefore  $$\frac{1}{2} \log (2 \pi \sigma^2) + \frac{\sigma_1^2 + \mu_1^2 - 2 \mu_1 \mu_2 + \mu_2^2}{2 \sigma_2^2},$$  which I can put as  $$\frac{1}{2} \log (2 \pi \sigma_2^2) + \frac{\sigma_1^2 + (\mu_1 - \mu_2)^2}{2 \sigma_2^2}.$$  Putting everything together, I get to   \begin{align*} KL(p, q) &= - \int p(x) \log q(x) dx + \int p(x) \log p(x) dx\\\\ &= \frac{1}{2} \log (2 \pi \sigma_2^2) + \frac{\sigma_1^2 + (\mu_1 - \mu_2)^2}{2 \sigma_2^2} - \frac{1}{2} (1 + \log 2 \pi \sigma_1^2)\\\\ &= \log \frac{\sigma_2}{\sigma_1} + \frac{\sigma_1^2 + (\mu_1 - \mu_2)^2}{2 \sigma_2^2}. \end{align*} Which is wrong since it equals $1$ for two identical Gaussians.  Can anyone spot my error?  Update  Thanks to mpiktas for clearing things up. The correct answer is:  $KL(p, q) = \log \frac{\sigma_2}{\sigma_1} + \frac{\sigma_1^2 + (\mu_1 - \mu_2)^2}{2 \sigma_2^2} - \frac{1}{2}$


In this case, why must $p$ divide $|G/N|$?

I am reading the proposition on page 102 of Dummit and Foote's Algebra, 3rd edition. Could someone explain why $p$ divides $|G/N|$ on the highlighted line?     Proposition 21.   If $G$ is a finite abelian group and $p$ is a prime dividing $|G|$, then $G$ contains an element of order $p$.      Proof:   The proof proceeds by induction on $|G|$, namely, we assume the result is valid for every group whose order is strictly smaller than the order of $G$ and then prove the result valid for $G$ (this is sometimes referred to as complete induction).   Since $|G| > 1$, there is an element $x \in G$ with $x \neq 1$.   If $|G| = p$ then $x$ has order $p$ by Lagrange’s Theorem and we are done.   We may therefore assume $|G| > p$.      Suppose $p$ divides $|x|$ and write $|x| = pn$.   By Proposition 2.5(3), $|x^n| = p$, and again we have an element of order $p$.   We may therefore assume $p$ does not divides $|x|$.      Let $N = \langle x \rangle$.   Since $G$ is abelian, $N \trianglelefteq G$.   By Lagrange’s Theorem, $|G/N| = |G|/|N|$ and since $N \neq 1$, $|G/N| < |G|$.   Since $p$ does not divide $|N|$, we must have $p \mid |G/N|$.   We can now apply the induction assumption to the smaller group $G/N$ to conclude it contains an element $\bar{y} = yN$, of order $p$.   Since $y \notin N$ ($\bar{y} \neq \bar{1}$) but $y^p \in N$ ($\bar{y}^p = \bar{1}$) we must have $\langle y^p \rangle \neq \langle y \rangle$, that is, $|y^p| < |y|$.   Proposition 2.5(2) implies $p \mid |y|$.   We are now in the situation described in the preceding paragraph, so that argument again produces an element of order $p$.   The induction is complete.      (Original image .)


Having just watched "Man of Steel", I have to wonder about the darker side of the movie. I've never heard of an instance before where      he'd snapped peoples necks. Even for truly bad guys.   Is there any other reference of this in canon?


Is there a better way than  to force a newline?

When I want to start a new line, I've always used
. I'm wondering if there's a better way, however, that only uses Markdown. I'm aware that if you insert two line breaks, leaving a blank line, it works, like this:  But what if I don't want a blank line like you see above this line? I don't have a problem with using
, but it just seems like such a common task shouldn't require four extra characters when Markdown is supported.


We had our flights cancelled by Covid 19 Virus closures

We were scheduled to travel Toronto to Lisbon on April 3-April 11,2020. The flights have been subsequently cancelled. We purchased the refundable type tickets which basically mean we will be charged 350.00 for each ticket. A far cry from the 2500 I spent. Problem is that they are not allowing me to refund any portion instead offer a voucher for a year. Not only is my 8 year old crushed by the fact that his tournament in Algarve is cancelled,but I am stuck with the fact that we are not and will not need a voucher. Why on a refundable ticket is there no way to get funds returned. They said they didn't cancel the flights, the Portuguese government did! Are they not owned by the government. So Sad!!!


Does a Ranger with dual daggers and Two-Weapon Fighting make four attacks at full strength plus Hunter's Mark at level 5?

We have a Ranger who has taken Two-Weapon Fighting and wields dual daggers.  He is saying that this allows him to attack with both weapons as part of his Attack action.  He says that each of those attacks does 1d4(dagger) + 5(dex) + 1d6(hunter's mark) damage.  He is also saying that at level 5, he can do this twice a turn, for a total potential of 28–60 damage every single turn.  He says that he will be getting even more extra attacks at higher levels.  (Not sure where he is getting this from, and the PHB only says one extra.)  Summary:   Does having two daggers with Two-Weapon fighting allow attacking with both in a single Attack action? Corollary to the above, does Extra Attack allow another attack where he can attack with both daggers again? Does he add the Dexterity modifier to every single hit? Does Hunter's Mark add 1d6 for every single hit?


How to define a new lable type such as fig and tab for a new float?

I have define a new float "scheme" and want to reference it as figure or table floats do. How could I define a new label type for the "scheme" float to reference it in the article? I have tried to use fig or tab labels, but they do not work. See the picture.   Tex code:  \documentclass[a4paper, 11pt]{article} \usepackage{caption}           % Use table caption \usepackage{chemfig}           % Use chemical strutures \usepackage{hyperref}  \DeclareCaptionType[fileext=ext, name=Scheme, placement=tbph!]{scheme} \captionsetup[scheme]{labelsep=period, font={small, bf}, skip=8pt}  \begin{document} This is a chemical reaction:  \begin{scheme}[h!] \renewcommand*{\figurename}{scheme} \centering \schemestart \chemfig{*6(-=-=-=)} \+ \chemfig{H_2} \arrow \chemfig{*6(-(-H)=-=(-H)-=)} \schemestop \label{sh1}  % define a new label type for scheme float \caption{Reaction of Benzene Synthesis} \end{scheme}  A relatively simple, as shown in Scheme~\ref{sh1}, is neutralized by the solution contained within it to form a charged double layer, which under the influence of an applied electric field leads to the electroosmotic mobilization of the solution.  \end{document}


finding $\lim_{n \rightarrow +\infty}\frac{n}{2^n}= ?$

Finding the limit below..:  $$\lim_{n \rightarrow +\infty}\frac{n}{2^n}= ?$$  I really think its 0. But intuitively, infinity over infinity. how can that be? indeterminate forms? Thanks


How can I make Karliah leave the Snow Veil Sanctum and show up at the Ragged Flagon?

Karlia never showed up at the Ragged Flagon: I was reading up on this and I saw that she can get caught at Snow Veil Sanctum. I returned and ran through to the sanctum and found that yes, she was there. I had brought the Falmor Translations to the Frozen Hearth and everything, and I am ready to confront Mercer. She, however, won't show at the Ragged Flagon.  I have waited for ten Skyrim days. I am currently in the sanctum looking at her and she won't converse. Every time I wait I find that she is either in another place in the sanctum or standing in her previous spot, practically mocking me. Any suggestions?  I have been reading through questions here and they are all similar but never exact. I play on an Xbox 360, so PC and PS3 won't help I'm afraid.


I thought people would be working on little code projects together, but I don't see them, so here's an easy one:  Code that validates a valid US Zip Code. I know there are ZIP code databases out there, but there are still uses, like web pages, quick validation, and also the fact that zip codes keep getting issued, so you might want to use weak validation.  I wrote a little bit about zip codes in a side project on my wiki/blog:    There is also a new, weird type of zip code.     I can do the javascript code, but it would be interesting to see how many languages we can get here.


After installing mysql using sudo apt-get install mysql-server, no question was asked to me to fill a specific password for root account. Logically, it means password is empty. It is confirmed when I have a look in the /var/log/mysql/error.log where I can find this information =>  2019-04-28T20:31:35.761063Z 1 [Warning] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.   But now, when I connect to PHPAdmin with root login and empty password, I have a message:  #1698 - Access denied for user 'root'@'localhost'   with a few more details:   mysqli_real_connect(): (HY000/1045): Access denied for user 'phpmyadmin'@'localhost' (using password: YES)   How do I solve this issue?


I would like to know which is correct form to write this sentences and the reason for that. Examples:  Do we stay in hotels? Are we stay in hotels?   Do I need shoes? Am I need shoes?  I need to understand the differences and know which one is the correct form.


Getting List of Words Input for Word Search Generator

In this program, this user will have the opportunity to generate their own word search. In the beginning of the program, the user will be shown a menu of instructions in which they can choose between these options: 1.  Create a word search 2.  Print the word search 3.  View solutions to the word search 4.  Exit the program  When choosing to create a word search, the user is asked to enter words of their choice, line by line. These words will be stored in a 1-D array.   The user will have to enter a minimum of 20 words, maximum at 260. At every batch of 20 words, the user will be asked if they want to add more words. If the user chooses to add more words, the program will prompt him/her to enter more words until they have reached the max number of words.   If they choose to stop adding more words, the program will jump right into converting the 1-D array to an Array List, and then create the word search, which is where I am having a little problem at.   if (choice == 1) {      System.out.println("Enter words of your choice line-by-line. You can enter a maximum of 260 words (i.e., 10 words per letter)");          System.out.println("");      String[] wordList = new String[260];      // This for loop will loop around with it`s body the user decides they have added enough words and wish to proceed      for (int i = 0; i < wordList.length; i++) {          wordList[i] = input.nextLine();            if (wordList[i] == wordList[19] || wordList[i] == wordList[39] || wordList[i] == wordList[59] || wordList[i] == wordList[79] || wordList[i] == wordList[99] || wordList[i] == wordList[119]|| wordList[i] == wordList[139]) {           System.out.print("Do you want to keep adding words? Enter Y/N: ");                   String answer = input.next().toUpperCase();                 if (answer == "Y") {                      wordList[i] = input.nextLine();                 } if (answer == "N") {                      break;                   }//end of inner if                 }//end of outer if              }//end of for loop          List<String> words = Arrays.asList(wordList);          createWordSearch(words);   When the user types in "N," the program is supposed to end the for loop and jump right into the part after }//end of for loop. Ive added 'break;' in order to stop the loop, but instead Im pretty sure it is stopping the entire program from proceeding. When I remove the 'break;' the program keeps prompting me to add more words (basically until there are 260 words added in total).   EDIT  So, I have fixed the problem up there thanks to the advice Ive received here. The program is doing what I want now, but I am getting aNullPointerExceptionfrom my for-each loop in thecreateWordSearch(words)` method.  public static WordArray createWordSearch(List<String> words){     WordArray wordArr = new WordArray();         // Have numAttempts set to 0 because the while loop below will add one every time we create a new word search            int numAttempts = 0;             while (++numAttempts < 100) { // There will be 100 attempts to generate our word array/grid              Collections.shuffle(words); // The words will be shuffled/randomized                     int messageLength = placeMessage(wordArr, "Word Search Puzzle");                     int target = arraySize - messageLength;                  int cellsFilled = 0;                     for (String word : words) { // For each word in the array list 'words'...                            cellsFilled += placeWord(wordArr, word); // NULL POINTER EXCEPTION!!! 'word' is not initialized I`m pretty sure


i have some weird problems with javafx PasswordField.this is my code:  public class Form1 implements Initializable { @FXML private PasswordField pass; @FXML private PasswordField confpass;  @Override public void initialize(URL arg0, ResourceBundle arg1) {     // TODO Auto-generated method stub  }   public void btn1_onclick(ActionEvent event){     String password = pass.getText();     String conf = confpass.getText();     if(conf == password)     {             System.out.println(":)");     }     else     {         System.out.println(password + "\t" + conf);     } } }   i type same word in both PasswordField but always the if condition is false and i see two same words in console!!!  how can i fix this?


Let A be a square matrix of order n. Prove that if $A^2 = A$, then $\operatorname{rank}(A) + \operatorname{rank}(I - A) = n$.

$A(I-A) = 0\implies\operatorname{rank}(A) + \operatorname{rank}(I-A)\le n$.   I managed to get this but wasn't able to go further. Any help would be appreciated.


WUBI error after installation on Windows 8 laptop

I try to install Ubuntu on a Laptop which actually runs with Windows 8.  After the Installation and restart, it´s this Error:  \ubuntu\wubildr.mbr  staus: 0x0000076


Why is the possibility $x-y = 0$ rejected?

I'll state the question from my textbook below:     If $x (1+y)^{1/2} + y(1+x)^{1/2} = 0$, for, $-1<x<1$, prove that      $\frac{dy}{dx} = - \frac{1}{(1+x)^2}$   Here's how I tried proving it:  $x (1+y)^{1/2} + y(1+x)^{1/2} = 0$  Rearranging and squaring we get:  $x^2(1+y) = y^2(1+x)$  Simplifying and factorizing we get:  $(x+y+xy)(x-y) = 0$  Case I:  $x+y+xy = 0$  From here we get the desired equation. Since the proof is irrelevant to my question, I'll skip it. But I note that if I replace the value of $y$ I get from this equation is in harmony with the original equation given in the question.  Case II:  $x-y = 0$  Clearly in this case,  $\frac{dy}{dx} = 1$  This is where the problem arises. Isn't this a valid answer too? Probably not, because the value of $y$ I get from this equation satisfies the original equation only for $x = -1,0$. Why is this? Here are the questions I'm looking answer for:  1) Is something wrong with squaring the equation?  2) Is there a mathematical reason to reject $x-y = 0$ as a possibility?  I am also interested in alternative methods to prove the required equation. So if you have any, feel free to post them as an answer. Any help would be appreciated.


What is the purpose of hiding communities if they are visible anyway?

My communities are visible to the Moderators and Stack Exchange employees, Its fine. But it says, "Other people may also be able to associate your presence on those communities with your public list in certain cases." If other people also can see my hiding communities then what is the uses of Hide communities here in Stack Exchange? Every general users are able to see my communities here.


Kubuntu 18.04 boots to black screen after installing Nvidia drivers version 396

I am running Kubuntu 18.04 with a GTX 980. I installed NVidia driver version 396, and now the machine boots to a black screen. CTRL+ALT+F1 through F6 do not do anything at any time while the machine is booting.  How can I fix this?


how to disable an apex commandbutton after first click . can someone help me out?  page : <apex:pageBlockSection  rendered="{!enableSpehere}"\>    controller :  boolean enableSpehere {get;set;}   inside constructor :  enableSpehere =false   then there is a method:    public void enableSphere()     {          enableSpehere=true;     }


Diff shows tag being added and removed in the same revision

On  (but I remember seeing it in other cases) the diff shows the same tag being both added and removed.


what is the difference between kind, type and sort

I see these sentences:     Newton invented a new type of microscope.   Newton invented a new kind of mathematics.   Apple invented a new sort of cameras.   What is the difference between kind, sort, and type?


Reducing image resolution (not image size)

I'm trying to post an avatar but the website says that the resolution needs to be reduced, the image size is already much lower than the sites maximum.


I'm annoyed by quite a simple problem in calculus (I apologize in advance if I'm not using adequate terms in English, I don't take the course in English nor am I a native speaker):  Let $f:\mathbb R\longrightarrow \mathbb R$ be a function which is continuous at $0$ and satisfies $f(x)=f(2x)\,\forall x\in\mathbb R$.  My question is how do I formally prove that for every $x<0$ $f(x)=c_1$, and for every $x>0$ $f(x)=c_2$, where $c_1,c_2\in \mathbb R$? After proving those two statements (or at least one of them WLOG) it would be quite easy to prove that $f(0)=c_1=c_2$ by the definition of continuity of $f(0)$ and thus $f(x)$ is constant. Those two statements are just so obvious to see that I can't think of any formal way of proving so without "cheating". Thanks in advance!


If you have the dual wielder feat, and you are riding a mount can you wield two lances. Also what would the damage dice be?


Is Java pass by value Or pass by reference Or both?

Consider following case.      List<Integer> listOne = new ArrayList<>();     List<Integer> listTwo = new ArrayList<>();     listOne.add(1);I think this happens due to      listOne.add(2);     listOne.add(3);     Collections.reverse(listOne);     listTwo = listOne;  //listTwo has same reference      Collections.reverse(listOne);     System.out.println(listOne);  //out put [1, 2, 3]      System.out.println(listTwo);  // same out put   Java is pass by value, where values (for non primitive types) happen to be references. I think this provide survival for java for this kind of scenario. To be honest why java try to avoid pass by reference and try to be different from some of other languages? while java still suffering from pass by reference behaviors?     Edit: additionally please some one explain what happen in above code


Can Blink be used to move through walls?

Let’s suppose a spellcaster casts  on himself. He then uses ready action to move freely around the ethereal plane while not on his turn. After this, when his turn starts again, he will be teleported again to the material plane, within 10ft of the original place he blinked from.  The question is, can the caster move through walls that are on the material plane while he is on the ethereal plane?   Since the blink spell sends the caster to the ethereal plane, and  this would allow the caster to actually see what is behind those walls safely. Is this possible?


iOS 7 Phone app interface doesn't show "Decline" button when it's asleep

In iOS 7, when the phone is in Sleep mode and I receive a call, I don't see the "Decline" button. All I see is a green "Answer..." button that requires me to slide to the right to answer the call. Is there anyway we can change that? I know that there are buttons for "Remind Me Later, etc" but I want the "Decline" button.   It works fine when the phone is not in Sleep mode.


Is it possible to do a fresh install? I only have a hard drive and windows 7 ISO file.


I want to exchange my XP for Kubuntu. However, I'm not very well versed with computers. I downloaded Kubuntu thinking it would automatically erase my windows XP and replace it. It took about 20 minutes to download but now I can't find it. I did a 'search'' and many Iso files turned up, but none that I could recognise as Kubuntu. What do I do now? Please make suggestions simple and in plain talk. Thank you.


int value does not convert correctly to double

so I am writing a house class and one of my methods calculates the total area of a house. And then one more method prints of all the details of the house that is my area method  public double getTotalArea(){         return ((300 * bedRooms) + familyRoomArea + livingRoomArea );     }  this is my print method  public String toString() {         return ("House Style =" + this.style + ",bedrooms = " + this.bedRooms +                 ",family room area = " + this.familyRoomArea + ",living room area = "                 + this.livingRoomArea + ",plot = " + this.plot + ", and square feet = " + (double)Math.round(this.getTotalArea() * 100)/100.0);     }  and this is my tester  String style1 = "colonial";         double familyRoomArea1 = 700;         double livingRoomArea1 = 500;         int bedRooms1 = 3;         double plot1 = 0.7;         House house1 = new House(style1,familyRoomArea1,livingRoomArea1,bedRooms1,plot1);         System.out.print("House 1: ");         System.out.print(house1.toString());  this is the current output I get when I run the program House 1: House Style =colonial,bedrooms = 3,family room area = 700.0,living room area = 500.0,plot = 0.7, and square feet = 2100.01  I don't know what I am doing wrong here because of the total area I should get 2100.00 but I keep on getting  2100.01 I tried many different things I even used it without the Math.round functions but still, it gives me this answer. Can I know what might be the issue and how I can fix this please thank you.


I have run the JB test for my data using two different commands. I am quite clueless about what conclusion I can make from the second picture which shows results of 0. This tells me that there is no normal distribution. However looking at the result from the jb resid command, the chi^2 statistics is 672, which is way over the chi^2 critical value and this is indicating normal distribution. The results are clearly contradicting one another. I read somewhere that a very high JB statistic indicates non-normal distribution and 672 does seem quite high.


I want to calculate the sum of this series:  $$S = 1\cdot1! + 2\cdot2! + 3\cdot3! + 4\cdot4! +\dots+ n\cdot n!$$  Is their any formula for finding this sum?


Windows first saves crash dumps to the pagefile. It only moves the data into a separate file after reboot. Why must they go into the pagefile first?

Windows first saves crash dumps to the pagefile. Windows only moves the data into a separate file (either a Memory.dmp file or a minidump file) after reboot.  Why must crash dumps go into the pagefile first?


Screen locks automatically after certain amount of time

The screen locks automatically after 5 minutes when I am watching YouTube on fullscreen. How can I fix this?


Compute the limit $\lim_{n\rightarrow\infty}\left(\frac{1+\sqrt[n]{a}}{2}\right)^n$

NOTE: L'Hopital's and Taylor series not allowed!  Taking the log and exponenting the entire thing I get $$\lim_{n\rightarrow\infty}\left(\frac{1+\sqrt[n]{a}}{2}\right)^n=\lim_{n\rightarrow\infty}e^{n\ln\left(\frac{1+\sqrt[n]{a}}{2}\right)}=\lim_{n\rightarrow\infty}e^{n\ln\left(\frac{1+\sqrt[n]{a}}{2}-1+1\right)\cdot\frac{\frac{1+\sqrt[n]{a}}{2}-1}{\frac{1+\sqrt[n]{a}}{2}-1}}.$$  Letting $k=\frac{1+\sqrt[n]{a}}{2}-1$ we see that the RHS can be simplified to  $$\lim_{n\rightarrow\infty}e^{nk\frac{\ln\left(k+1\right)}{k}}.$$  It follows that $k\rightarrow0$ as $n\rightarrow\infty,$ and $\ln(k+1)/k$ then tends to $1$ (standard limit). So we can write  $$\lim_{n\rightarrow\infty}(e^{k})^n=\lim_{n\rightarrow\infty}\left(\frac{e^{k}-1+1}{k}\cdot k\right)^n=\lim_{n\rightarrow\infty}\left( \frac{e^k-1}{k}\cdot k+1\right)^n=(1 \cdot0+1)^n=1.$$  The answer should be $\sqrt{a}.$ Why is my method wrong?


Should I use "important" or "importantly" in the introductory phase of a sentence?

Should I use important or importantly in the introductory clause of the second sentence:      Appellant's argument is premature. More important, it lacks merit.   Google NGram shows a significant preference for "more important."  Recently, however, it appears the democracy of usage has swung slightly in favor of "more importantly."   I prefer the former, but I am more concerned about learning which one is grammatically proper, and the particular rules that control the analysis. Can someone walk me through it?


Does it make sense to answer old questions?

I always wonder if I read questions and nobody ever focused on one special point - I constantly think if it is worth the time to answer them.   They usually do not get any upvotes no matter how good the answer is and so remain in the mostly unread lower part of the page.   So should we consider a question as a knowledge base for a topic, or just a way to answer one single person?


Different civilizations obviously have different priorities. For example, Gandhi always seems to rush nuke technology and the Mongols will most likely start invading and spread like mad. Are these variables public knowledge? Can you tell by who you are playing what strategy they will adopt during the game?


When I build a template class can I make the class a pure abstract class?  template <class Block> class Filter { public:     Filter();     void add(Frame* frame);     Block* get(); private:     Block* mBlock; };  template <class Block> Filter<Block>::Filter<Block>() { }  template <class Block> void Filter<Block>::add(Frame* frame) {     mBlock = new Block(                 frame->getSampleRate(),                 0xFFFFFFFF,                 frame->getBlockSize(),                 ); }  template <class Block> Block* Filter<Block>::get() { return mBlock; }   the Block class is a pure virtual class and is the base class for what is being passed into the template.  class Block { public:     explicit Block(DWORD dwSampleRate, DWORD dwMicrophoneIndex, DWORD dwBlockSize);     ~Block();      DWORD getSampleRate();     DWORD getMicrophoneIndex();     DWORD getBlockSize();      virtual void process() = 0; private:     DWORD mdwSampleRate;     DWORD mdwMicrophoneIndex;     DWORD mdwBlockSize; };   The implementer will create a derived class from Block.  class FooBlock : public Block { public:     FooBlock(DWORD dwSampleRate, DWORD dwMicrophoneIndex, DWORD dwBlockSize);     void process(); };   implemented as:  FooBlock::FooBlock(DWORD dwSampleRate, DWORD dwMicrophoneIndex, DWORD dwBlockSize) : Block(dwSampleRate, dwMicrophoneIndex, dwBlockSize) { }  void FooBlock::process() { }   To invoke the filter   Filter<FooBlock>* filter = new Filter<FooBlock>();   which yields the message:     LNK2019: unresolved external symbol "public: __cdecl Filter::Filter(void)" (??0?$Filter@VBlock@@@@QEAA@XZ)   referenced in function "public: __cdecl MainWindow::MainWindow(class   QWidget *)" (??0MainWindow@@QEAA@PEAVQWidget@@@Z)   Can I create a template that requires a base class?  Or do I need find a different technique to implement this?


Find the value of $$\cos ^2\theta+\cos^2 (\theta+1^{\circ})+\cos^2(\theta+2^{\circ})+......+\cos^2(\theta+179^{\circ})$$  Can anyone teach me where to start with? I've no idea.


Are surjective functions a pointless concept?

What is the point of the concept of surjective or onto functions if you can just restrict the co-domain of your function to its image? Injectivity or 1-to-1ness is actually the defining property of bijections (sometimes called 1-to-1 correspondences), while all the question of surjectivity does is derail the argument into checking whether the image equals the co-domain.  Am I wrong in thinking this? What am I missing? Only situation where this concept could be marginally useful that I could think of would be some function for which it is easier to find an element of the co-domain for which no pre-image exists than to actually find the image itself.


I am unable to delete a filename named -r with rm -rf -r Is there any special trick to remove it?


How to invert sound coming in through speakers and play it back?

Hi I know in Audacity you can record a sound, invert it, and then play it, but I'm looking for something automatic.  Basically this program would listen to all sound coming in, invert them, and then play them at the same time. All instantly. Is this possible?


confidence intervals 95% we do z = qnorm( 0.95) or z = qnorm( 0.975)

I want to know for sure when we compute the 95% confidence interval for mean/prop, we get z = qnorm(0.95) or z = qnorm(0.975)?


Understanding metaclass and inheritance in Python

I have some confusion regarding meta-classes.  With inheritance  class AttributeInitType(object):     def __init__(self,**kwargs):        for name, value in kwargs.items():           setattr(self, name, value)  class Car(AttributeInitType):      def __init__(self,**kwargs):         super(Car, self).__init__(**kwargs)     @property     def description(self):        return "%s %s %s %s" % (self.color, self.year, self.make, self.model)  c = Car(make='Toyota', model='Prius', year=2005, color='green') print c.description   With meta class  class AttributeInitType(type):    def __call__(self, *args, **kwargs):        obj = type.__call__(self, *args)        for name, value in kwargs.items():            setattr(obj, name, value)        return obj  class Car(object):    __metaclass__ = AttributeInitType     @property    def description(self):        return "%s %s %s %s" % (self.color, self.year, self.make, self.model)   c = Car(make='Toyota', model='Prius', year=2005,color='blue') print c.description   As above example is not useful as practically but just for understanding,  I have some questions Like,   What is the difference/similarity between a meta class and inheritance? Where should one use a meta class or inheritance?


Google Spreadsheet: Adding formulas to Google Forms responses rows

I have a sheet with form response data in several columns, say A:G. Some of the data are numerical and I'd like to have some calculations done on them, e.g. in columns H through J. I have already found out any stretched formulas get wiped out as new lines from the form get pulled in.  So I created a new sheet, imported the data using arrayformula, but still, I don't know how to have a formula for every row in columns H:J (except the header). I can only stretch the formula within a fixed number of rows, but don't know how to make it autoadjust to newly incoming data.  I wondered if I could use a script that would be triggered with the form being submitted, adding the formulas to the new lines, but that's rather inelegant.  : Sheet1 contains form data, Sheet2 imports them using arrayformula.


Let $f$ and $g$ be continuous at $ x=a$, with $f(a)<g(a)$. Prove that there exists a neighborhood $I$ of a such that $f(x)<g(x)$ for all $x \in I$.

Let $f$ and $g$ be continuous at $x=a$, with $f(a)< g(a)$. Prove that there exists a neighborhood $I$ of $a\in\mathbb{R}$ such that $f(x)< g(x)$ for all $x \in I$.  It might be helpful to use the theorem that states: If $\lim_{ x\to a} f(x)=L$, $L$ is not $0$, then there exists $\delta>0$ such that $f(x)>L/2>0$ for 0$ < |x-a| < \delta$.


Replace in string object property global

I have an object with tow properties and string, where I have the object name. I want to change object name with object value global, but not working. let obj = {   name: 'year',   value: '2020', };  let str = 'year year';  str.replace(/obj.name/g, obj.value);


Why does the king of the Numenoreans not get to choose between elf and man?

I just finished up the Silmarillion and an idea that confused me was that the heirs of Earendil could choose their race, as when Arwen chooses to be mortal for Aragorn, but the Numenorean king, descended from Elros, attempts to sail to Aman to gain immortality, but doesn't that imply that the heirs of Elros didn't have the same choice?


What are some good books for learning general relativity?


Recently, I have been translating a foreign paper that has main title and subtitle.  My trial:  \documentclass[UTF8]{ctexart} \usepackage{amsmath} \usepackage{amssymb} \usepackage{graphicx} \usepackage{epstopdf} \usepackage{inputenc} \usepackage{geometry}  \geometry{left=2.5cm,right=2.5cm,top=2.5cm,bottom=2.5cm} \begin{document} \title{  Simulatin Modelling Practice and Theoty \\  \begin{large}    Common Simulation of a SCARA robot with PD and learning controller \end{large} }  \end{document}   However, it failed to achieve that effect. The main title is Simulatin Modelling Practice and Theory, subtitle is »Simulation of a SCARA robot with PD and learning controller«. So my question is how to alter it?


Limits of this function in the polar system

Given is the following double integral - $$\iint\limits_{D}\frac{1}{(x^2+ y^2)^2}\,dy\,dx$$ $D$ is the region for $x\in[1,2]$ and $y\in[0,\sqrt{2x-x^2}]$ How would the limits of integration be derived if one was to convert the coordinate system from Cartesian to polar? So far, I can only understand that $\theta$ would hold an upper bound of $\frac{\pi}{4}$ with a lower bound of $0$ and could derive by algebra that $r$ would hold an upper bound of $2\cos\theta$. By the same algebra, the lower bound for $r$ turns out as $0$.  Here's my go at finding bounds for $r$ $$y = \sqrt{2x - x^2}$$ $$x^2 + y^2 = 2x$$ $$r^2(\cos^2\theta + \sin^2\theta) = 2r\cos\theta$$ $$r^2 - 2r\cos\theta = 0$$ Thus, $r$ is found to be $0, 2\cos\theta$ From a solution that I found, the lower bound for $r$ was given as $\sec\theta$. Could someone please explain how that came to be? I've been at it for a day now


export/import gnome-terminal profile settings

I have a several systems running Ubuntu 16.04.  I use git to manage my . files so I can maintain the same settings across systems, but the gnome-terminal settings are not in these files and instead in gconf.  I'm now adding an Ubuntu 18.04 system and I'd like to export my settings from 16.04 and import them on my 18.04 system.  How can I accomplish this for gnome-terminal settings from 16.04 to 18.04?


Find an infinite group in which every element $g$ not equal to $e$ has order $2$. In this case $e$ is the identity element.    I have tried so many times but i can't really seem to understand what the question wants. Can someone please help me out in solving this question.


How can I find out what dlls are being referenced from another dll

Is it possible to find out what other dlls a certain dll is referencing? I can't run it, I just want to find out what other files it's referencing. Maybe there's a nice program out there that can find this information?


Apex action is not visible in Visual flow in salesforce

I have created an InvocableMethod method, but it is not visible in visual flow to add Apex Action.  public class ApprovalProcessService {      @InvocableMethod     public static List<ApprovalProcessResult> recallApprovalProcess(Id[] recordIds) {          List<ProcessInstance> instances = [SELECT Id FROM ProcessInstance WHERE TargetObjectId = :recordIds[0] AND Status='Pending' limit 1];          ApprovalProcessResult res = new ApprovalProcessResult();          if(!instances.isEmpty()){             List<ProcessInstanceWorkitem> workItems = [SELECT Id FROM ProcessInstanceWorkitem WHERE ProcessInstanceId = :instances[0].Id limit 1];              Approval.ProcessWorkItemRequest req = new Approval.ProcessWorkItemRequest();              req.setWorkItemId(workItems[0].Id);             req.setAction('Removed'); // This means to remove/recall Approval Request             req.setComments('Apex Recall Approval.');              Approval.ProcessResult result = Approval.process(req);              res.isSuccess = result.isSuccess();              if(! res.isSuccess) {                  String errorMessage = '';                 for(Database.Error error: result.getErrors()){                     errorMessage += error.getMessage();                 }                  res.message = errorMessage;             }          } else {             res.isSuccess = true;             res.message = null;         }          return new List<ApprovalProcessResult>{res};     }      public class ApprovalProcessResult {          @InvocableVariable(required=true)         public Boolean isSuccess;           @InvocableVariable(required=true)         public String message;      } }   I am not getting, what is flaw in this code?


Is there a way to not show my full name on Google Docs?

I want to share a document with my guild in an MMO, but for obvious reasons I don't want every single person to have knowledge of my real name. Is there a way to make it so that the name displayed is different than the account's profile name? (I'd rather not change that.)  If not, can I turn off peoples' ability to see my account name when it is viewing a document, and would make me appear instead as one of the various "Anonymous [Animal]"s?


apt-get stuck at 0 [Connecting to us.archive.ubuntu.com]

When I do upgrade it gets stuck here:  user@plato:~# sudo apt-get upgrade Reading package lists... Done Building dependency tree        Reading state information... Done Calculating upgrade... Done The following packages will be upgraded:   bind9-host coreutils cpio curl dnsutils libbind9-90 libc-bin libc-dev-bin   libc6 libc6-dev libcgmanager0 libcurl3 libcurl3-gnutls libdns100   libdrm-intel1 libdrm-nouveau2 libdrm-radeon1 libdrm2 libisc95 libisccc90   libisccfg90 libjasper1 liblwres90 libplymouth2 libsepol1 libssl-dev   libssl-doc libssl1.0.0 linux-libc-dev mime-support multiarch-support ntp   ntpdate openssl plymouth plymouth-theme-ubuntu-text python3-distupgrade   ubuntu-release-upgrader-core unzip 39 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 16.0 MB of archives. After this operation, 12.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y 0% [Connecting to us.archive.ubuntu.com (2001:67c:1562::15)] ░   When I do update it gets stuck here:  user@plato:~# apt-get update 0% [Connecting to us.archive.ubuntu.com (2001:67c:1562::14)] [Connecting to sec░   I'm able to ping us.archive.ubuntu.com just fine:  user@plato:~# ping us.archive.ubuntu.com PING us.archive.ubuntu.com (91.189.91.23) 56(84) bytes of data. 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=1 ttl=54 time=81.5 ms 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=2 ttl=54 time=81.5 ms 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=3 ttl=54 time=81.5 ms 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=4 ttl=54 time=81.4 ms ^C --- us.archive.ubuntu.com ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3004ms rtt min/avg/max/mdev = 81.425/81.528/81.582/0.355 ms   What can i do to fix this?    What I have tried so far.  I've tried following directions on this blog:   To force apt-get to use IPv4 exclusively   Create a file in /etc/apt/apt.conf.d/99force-ipv4 Add this line to newly created file Acquire::ForceIPv4 false; Apt-get will now use IPv4 exclusively


Does Earth get gravity due to it's spinning?

Consider my example below. Example: 1. A man standing on grass(point) on earth surface. 2. He jumped. 3. And returned back, and he could find the same grass(point) under his foots. Right?  If earth is spinning, when he is on air (on jump) and return back to the earth surface, the grass(point) should be moved right or left side based on rotating direction of earth Right. But it did not happen on real scenario.   Newton told that as "Gravity". and the definition would be  the force that attracts a body towards the centre of the earth, or towards any other physical body having mass.  But from my example the man attaching with a earth surface by some force due to not only of earth's massive body, but also for it's spinning.   Because If gravity only about to mass means the man return back to earth surface is OK, but how could he feel like settle down on same place on earth surface that he stood before he jumps.  I am really curious about the answer.


Representing floating point numbers in c

I have read that floating numbers are stored as per IEEE 754 representation and sometimes approximate value is displayed if its not possible to represent the number.  I have written the following code in which i am extracting fractional part then multiplying it by 10 nine times inside the loop. At the end of the loop the value is 142000000.000000 (variable g). I multiplied it again with 10 outside the loop and got the result as 1419999999.999999.  I stored the value which was calculated inside for loop explicitly in another variable(k) and multiplied it with 10 and got the result as 1420000000.000000  Can you please tell me why the difference how it is able to store the value correctly in the second instance (In variable k).  #include<stdio.h> #include<math.h> int main() {     double f=3.142,g,i;     int j;     g=modf(f,&i);      printf("Inside loop");     for(j=1;j<=9;j++)     {         g = g * 10.0;         printf("\n%lf",g);     }     printf("\nLoop ends");      g = g * 10.0;     printf("\nThe value of g is %lf",g);      double k = 142000000.000000;     k = k * 10.0;     printf("\nThe value of k is %lf",k); }   Output  Inside loop  1.420000  14.200000  142.000000  1420.000000  14200.000000  142000.000000  1420000.000000  14200000.000000  142000000.000000  Loop ends  The value of g is 1419999999.999999  The value of k is 1420000000.000000


Clean way of italicizing whole preface with \emph inside (which will de-italicize)

I would like to set a part of the LaTeX document in italics but with using \emph{...} for emphasizing inside. This is easy to do within single paragraph where \emph can be easily nested. But since \text@command is not \long, it does not extend to multiple paragraphs.  If there is no standard way of doing that, I can always use \bgroup\itshape ... \egroup but I need to trick \emph into knowing it already is in italicized text so that it will change back to upright.  I don't find my current solution \bgroup\itshape\def\emph#1{{\rm #1}} ... \egroup is particularly elegant. Something better would be appreciated.  EDIT: While \emph does switch correctly inside \itshape, the problem was found to be caused by \usepackage{fontspec}:  \documentclass{minimal} \usepackage{fontspec} % \usepackage{libertine} \begin{document} \itshape This is an \emph{emphasized} word. \end{document}


How to disable mouse integration in VMware Workstation Player?

My question is similar to  except it's about VMware Workstation Player instead of VirtualBox.  How do I disable mouse integration? I want the VM to "capture" my mouse. One option is to pass my mouse directly to the VM, but that's more difficult if I need to exit the VM (I want to just use Ctrl+Alt).  I'm using "VMware Workstation 15 Player (Non-commercial use only)"


Can we have a search option for questions with bounties? (No, I don't mean hasnotice:1)

Over the years, there have been multiple requests asking how to search for questions and answers with bounties.    (Jun 21 '10)  (Aug 26 '10)  (Oct 21 '10)  (Nov 28 '10)  (Feb 7 '11)  (Mar 17 '11)  (Sep 11 '11)  (Oct 7 '11)  (Feb 20 '12)  (Mar 31 '12)  (Apr 24 '12)  (Aug 26 '12)  (Nov 30 '12)  (Dec 11 '12)  (Jan 26 '13)  (Feb 27 '13)  (Aug 26 '13)  (Sep 26 '13)  (Feb 10 '14)  (Feb 26 '14)  (Sep 12 '14)  (Feb 26 '15)  (Jul 31 '15)  (Nov 6 '15)  (Nov 15 '15)  (Apr 21 '16)   Currently, there isn't a search option to search questions with bounties. (, but it includes posts with .)  Can a search option hasbounty: be added to find questions with bounties?


554 5.7.1 : Relay access denied centos postfix

I have problem in send mail from postfix in centos  I have following  for sending mail but I am getting error.  As in the link I tried following commands  telnet localhost smtp  Trying ::1... Connected to localhost. Escape character is '^]'. 220 mydomain.com ESMTP Postfix ehlo localhost 250-mydomain.com 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN mail from:<domain.com> 250 2.1.0 Ok rcpt to:<test@gmail.com> 554 5.7.1 <test@gmail.com>: Relay access denied   Edit-1  In terminal this works  echo TEST | mail -v -s "Test mail" testing@gmail.com   my postconf -n shows belog information  alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix daemon_directory = /usr/libexec/postfix data_directory = /var/lib/postfix debug_peer_level = 2 home_mailbox = Maildir/ html_directory = no inet_interfaces = localhost inet_protocols = all mail_owner = postfix mailq_path = /usr/bin/mailq.postfix manpage_directory = /usr/share/man mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain mydomain = dummy.com myhostname = dummy.com mynetworks = all mynetworks_style = host myorigin = $mydomain newaliases_path = /usr/bin/newaliases.postfix queue_directory = /var/spool/postfix readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES sample_directory = /usr/share/doc/postfix-2.6.6/samples sendmail_path = /usr/sbin/sendmail.postfix setgid_group = postdrop unknown_local_recipient_reject_code = 550   What configuration I have to perform to send mails from my server.


I have this battle point booster that is 80% already activated ,but I want to buy the 400% one to activate it at the same time.  Do they stack?


I understand that this command attempts to write to nowhere or a null device but what does 2>&1 mean here?  wget -q -O - http://yourwebsite.com/wp-cron.php?doing_wp_cron > /dev/null 2>&1


Has it ever been addressed why Galifreyans and Humans look alike?

Whenever someone asks The Doctor, "But, you look human?", he replies, "You look Gallifreyan."  Has this ever been mentioned in the canon why this resemblance between two different races exist? Do they share the same origin or, is the human race an accidental by-product of an ancient cloning experiment, or something?


Two 3d view windows: one in edit mode, one in object mode

I want to display two 3d view windows at once. But I want one to be in Edit Mode, and the other in Object mode. However, when I change the mode of one window the other 3d view window automatically changes. How can I make it so changing the mode in one window does not affect the other window?


Why is this glass Cycles material casting solid shadows?

I created a glass cone with black seams (the seams are a diffuse not transparent material).    When I shine light on it, the cone casts a solid shadow. Why is this?   I would like to have a (semi) transparent shadow cast from the glass and a full shadow from the seams.  Here is the link where you can (hopefully) download the blend file:


Linear Algebra Matrix to the third power is the identity

Can you guys think of any way to find a 2x2 matrix that when raised to the third power is the identity? I know there is the obvious answer of the identity itself, but I was specifically wondering about matrices that would take more than one elementary row operation to achieve. Thanks in advance to anyone who can give me some insight!


Which is faster in PHP, $array[] = $value or array_push($array, $value)?

What's better to use in PHP for appending an array member,  $array[] = $value;   or  array_push($array, $value);   ?  Though the manual says you're better off to avoid a function call, I've also read $array[] is much slower than array_push(). What are some clarifications or benchmarks?


Could you destroy the Death Star by having a ship come out of hyperspace in the middle of it?

So the Death Star is huge, right? Would it be possible to coordinate a hyperdrive to come out of hyperspace in the middle of the Death Star?   Maybe a small ship wouldn't be enough to destroy it,  but let's say it was something the size of the Home One?  Or maybe some sort of crazy explosive device inside a smaller ship.  As for the pilot, I'm thinking maybe it could be done by remote control? Or a kamikaze pilot willing to sacrifice himself to take out the Empire's worst weapon.  But I like remote control better.   Could this plan work?  And whether yes or no,  why?   To clarify, I may not be understanding hyperspace correctly, but I'm not talking about crashing into it from the outside. I am suggesting you  so that you appear in the middle of the Death Star.  Related:


I've changed the "Q&A Emails" settings to email I use. How do I change "Newsletter" email setting?


mysql Trying to select latest timestamp only

I am trying to join 2 tables and select the latest timestamp only and the field values associated with that latest timestamp  Data tables:  device_count  id  device_name     platform    version     timestamp 1   abc             123         x           2013-12-30 2   abc             123         y           2014-01-01 3   def             345         x           2013-12-30   device_list  id      device_name     Network     Division    Market 2657    def             a           f           d 2656    abc             a           b           c   The desired result should be   device_name     platform    version     network     division    market  timestamp abc             123         y           a           b           c       2014-01-01 def             345         x           a           f           d       2013-12-30   I have used the following query but I'm not getting the correct results  SELECT device_count.device_name, device_count.platform, device_count.version, Max(device_count.`timestamp`), device_list.Network, device_list.Division, device_list.Market FROM device_count INNER JOIN device_list ON device_count.device_name = device_list.Device_Name GROUP BY device_count.device_name, device_count.platform, device_count.version, device_list.Network, device_list.Division, device_list.Market   It results in   device_name     platform    version     network     division    market  timestamp abc             123         x           a           b           c       2013-12-30 abc             123         y           a           b           c       2014-01-01 def             345         x           a           f           d       2013-12-30   The first record should not be included. I only want the version and platform values from the latest timestamp (record id 2)


I had installed Cryptkeeper in Ubuntu 16.04 lts. I have upgraded Ubuntu 16.04 to 18.04. After I upgraded to Ubuntu 18.04 , I completely lost my file which were encrypted through Cryptkeeper in Ubuntu 16.04. There are only folders where I kept my files. Now when I try to install Cryptkeeper in Ubuntu 18.04 through terminal it says  E: Package 'cryptkeeper' has no installation candidate   Does anyone know how to bring back my files without degrading Ubuntu to 16.04 LTS? Or, does anyone know of another file encryption program, as easy to install and use as Cryptkeeper, that will work reliably on Ubuntu 18.04 ?


Using the definite article with grocery products

If you ask someone working at a store 'Where's milk?' would that be right grammatically or does it have to be 'Where's the milk?' I know in the kitchen you would say 'Where's the milk?' or 'Where's the salt?' but i'm not sure if it would be the same case here perhaps because in the store you would be talking about milk in general. Even if 'Where's milk?' is wrong, then why does 'Where's milk in this store' sound right?


Is there an exact command for restarting GNOME Shell in Ubuntu 20.04 corresponding to Alt + F2 + 'r' + Enter?

Is there a way to restart GNOME Shell other than by using Alt + F2, R + Enter? With respect to the question, I have gone through , but I didn't get what I was looking for. I am looking for a command which exactly does what Alt + F2, r + Enter do. Please note that I am not willing to do the gnome-shell -- replace command... I did check both the things Alt + F2,r Enter and gnome-shell --replace... There is a lot of difference, I found...


Why worry about the Night King if they have the wall?

In Season 6, we find out the following about the magical properties of the wall:     BENJEN: This is where I leave you.   BRAN: You're not coming with us?   BENJEN: The Wall is not just ice and stone. Ancient spells were carved into its foundations. Strong magic to protect men from what lies beyond. And while it stands, the dead cannot pass. I cannot pass.   —"Winds of Winter" (Game of Thrones, S06E10)   So why would the men of Westeros need to worry about the Night King and his army? Couldn't they sit back and enjoy the wall's protection?


Travelling with an Ecuadorian and Canadian passport

I am travelling to Costa Rica from Ecuador.  I have a Canadian and Ecuadorian passport.  I want to travel with both because I do not need a visa to enter Costa Rica if I use my Canadian passport. Which passport number do I give the airline to buy my ticket? To leave and enter Ecuador I need to show them my Ecuadorian passport is that correct?  To enter and leave Costa Rica I would show my Canadian passport is that correct? Do I ever show both passports?


Excel 2010 removes data from clipboard, how can I stop it?

The order of my actions is:   Copy data from pivot table from second sheet. Paste data as value into first sheet. Notice that something is wrong in the data. Go back to the second sheet and change data. Copy data from changed data. Return to first sheet. Select and delete wrong data. Try to paste new copied data from second sheet but clipboard is empty.    Why does Excel remove data from the clipboard when I select and delete data from a sheet? How can I change this strange behavior?


VirtualBox USB 'Add device filter` does not work under 14.04

To make USB devices accessible to a guest OS under VirtualBox, one must     i) install the appropriate extension pack    ii) navigate to 'Settings ----> USB' in the VirtualBox menu and  iii) tick 'Enable USB 2.0 (EHCI) Controller   iv) add a `USB device filter`    Step iv) requires selecting a USB device filter by clicking on a list of available USB devices which appears at the mouse-pointer position    when clicking on the 'Add new USB filter` icon on the right margin ( a USB icon with a green plus sign ) when pressing ALT+INS     In either case one will see a list of USB device candidates currently attached to the host system.     These can then be selected and will appear permanently under the 'USB Device Filters' list of the USB menu.    This does not work under 14.04.   When attempting to add an attached device ( clicking on appropriate icon or pressing ALT+INS )      VirtualBox can not see any of the connected USB devices, resulting in a <no devices available> message. Trying to enter the device details manually into a blankly created USB device filter does not work either. Booting the guest OS ( Win 7 ), you are not able to see any 'removable drives'.   The obvious items were all checked:   VirtualBox installed from repository ( apt-get install ) App reports version 4.3.10 Appropriate VirtualBox extension pack ( 4.3.1r93733 ) successfully downloaded+installed from the Oracle site   As mentioned previously on the the same box with 12.04 installed everything works as it should and Win7 can see the removable drive as expected.  As a last resort various permutations of VM settings, USB sticks, e.t.c. were tried without achieving the desired result.   Has anyone encountered the same issue? Has anyone encountered similar difficulties? Has anyone been able to work around the problem? ( remember manual entry of device details into an empty filter entry has not worked )   Does anyone know if this is an issue   with VirtualBox? with the current version of the VirtualBox extension pack? or perhaps even with Trusty Tahr itself?   I have full USB functionality on my 14.04 host.


Best practice about average time to accept an answer and accept answer decision

What is the common sense for the time to accept a user answer? For example, I usually think that I need to wait, for example, 1 week or more, because some questions have more than one answer and I like to hear different answers than accept the first one that appears. I want to read more answers about this subject. Another point I want to discuss: is there a option where I can pass the decision for the community chooses what is the best answer in my questions? Thank you!


This question is motivated by a little anecdote. I was at home teaching some secondary school math to a relative. At some relax time, he glanced at a book I had over the table - it was some text about analytical number theory that I had recently bought, second hand- and I  explained him that that was an area of mathematics quite arcane to me, that I'd like to learn something about it in some future, but I had little hopes...   He looked puzzled for a moment, and then asked me: "But, wait a moment... You don't know all the mathematics?"  This happened months ago, and I'm still laughing. But also (and here comes the question) I'm still thinking about how to make some picture of this issue: the big extension of "the land of mathematics", in diverseness and ranges of depth - and the small regions that one has explored.  I was specifically looking for some kind of bidimensional (planar?) chart, perhaps with the most basic/known math kwowledge in the center, and with the main math areas as regions, placed according to its mutual relations or some kind of taxonomy.   (I guess this should go in community wiki)


Find closed form of sum of fraction of binomial coefficients

can somebody give me a hint for this exercise, where I have to find the specific closed form?     $\sum_{k=0}^m \frac{\binom{m}{k}}{\binom{n}{k}}, m,n\in\mathbb{N}$ and $m\leq n$   What I have done so far:  $\sum_{k=0}^m \frac{\binom{m}{k}}{\binom{n}{k}} = \sum_{k=0}^m \frac{\frac{m!}{(m-k)!\cdot k!}}{\frac{n!}{(n-k)!\cdot k!}} = \sum_{k=0}^m  \frac{m!}{n!}\cdot \frac{(n-k)!}{(m-k)!} = \frac{m!}{n!}\cdot \sum_{k=0}^m  \frac{(n-k)!}{(m-k)!}$   Look at example 1: $n=8, m=5$  $\frac{5!}{8!}\cdot(\frac{8!}{5!} + \frac{7!}{4!} +\frac{6!}{3!} +\frac{5!}{2!} + \frac{4!}{1!} +\frac{3!}{0!}) = \\\frac{5!}{8!} \cdot (8\cdot7\cdot6+7\cdot6\cdot5+6\cdot5\cdot4+5\cdot4\cdot3+4\cdot3\cdot2+3\cdot2\cdot1) = \\ \frac{5!}{8!} \cdot (336+210+120+60+24+6) = \frac{5!}{8!}\cdot 756 = 2.25$  I can't find a pattern.  Edit 1: Maybe there is an approach with recursion.  Edit 2: Okay I found the solution.   $\sum_{k=0}^m \frac{m!}{n!}\cdot \sum_{k=0}^m  \frac{(n-k)!}{(m-k)!}= \frac{m!}{n!}\cdot\frac{1}{4}\cdot t\cdot(t+1)\cdot(t+2)\cdot(t+3)$ with $t=(n-m)!$  Edit 3: This formula works well for example 1, but fails for example 2: $n=9, m=3$  $\frac{3!}{9!}\cdot(\frac{9!}{3!} + \frac{8!}{2!} +\frac{7!}{1!} +\frac{6!}{0!})  = \\\frac{3!}{9!} \cdot (9\cdot8\cdot7\cdot6\cdot5\cdot4+8\cdot7\cdot6\cdot5\cdot4\cdot3+7\cdot6\cdot5\cdot4\cdot3\cdot2+6\cdot5\cdot4\cdot3\cdot2\cdot1) = \\ \frac{3!}{9!} \cdot (60480+20160+5040+720) = \frac{3!}{9!}\cdot 86400 = 1.428$  So I have still no general solution. Can someone help?


department.txt contains column as ID, Department I am using below to change the order to Department,ID   But if i further update the command to below   Then department.txt becomes empty, without any output. If i use some other file instead of the same file which i am reading, then it works.  I understand i am reading and updating the same file, but as per my understanding is | should take care of it, as internally it must be storing the the output somewhere in its memory and dumping it in the file which i have asked. Isnt it ? Can someone throw some insight on how it works ?  Note: I know there are many similar questions, but none of them have really answered how internally | works, which is the fundamental question for which i need an answer.


Show that $f(x,y)$ is continuous at the origin but not differentiable at the origin

Show that $f(x,y) = \frac{xy^2}{x^2+y^2}$ (where $(x,y) \neq0$, and $f(0,0) = 0$) is continuous but not differentiable at $(0,0)$.   I have shown continuity but am stuck on differentiability. I cannot seem to find a way in my text to show that the above is not differentiable.  Thanks


Problems with mysql-workbench for Ubuntu 20.04

Got an Ubuntu 20.04 VirtualBox VM and after installing MySQL server, wanted to install MySQL Workbench. I tried installing MySQL Workbench with APT first and ran: sudo apt install mysql-workbench sudo apt install mysql-workbench-community  Both commands resulted in: E: Unable to locate package NAME_OF_THE_PACKAGE  According to , I ran sudo apt-add-repository universe  but when I do it, I get 'universe' distribution component is already enabled for all sources.  This saying, both that question and the one linked to that one didn't help fixing this problem. If I go to Ubuntu Software and install from there Workbench, I'm able to but it gives a warning right away saying  Unsuported Operating System You are running Workbench on an unsupported operating system. While it may work for you just fine, it wasn't designed to run on your platform. Please keep this in mind if you run into problems.  When trying to connect to localhost, I'm not able to even after as said in  (create a user called admin with a specific password and give it permissions) due to the following error  Cannot Connect to Database Server Your connection attempt failed for user : An AppArmor policy prevents this sender from sending this message to this recipient; ...  Note: there's a  but they use Snap Store.