What exactly are moments? How are they derived?

We are typically introduced to method of moments estimators by "equating population moments to their sample counterpart" until we have estimated all of the population's parameters; so that, in the case of a normal distribution, we would only need the first and second moments because they fully describe this distribution.   $E(X) = \mu \implies \sum_{i=1}^n X_i/n = \bar{X}$  $E(X^2) = \mu^2 + \sigma^2 \implies \sum_{i=1}^n X_i^2/n$  And we could theoretically compute up to $n$ additional moments as:  $E(X^r) \implies \sum_{i=1}^nX_i^r /n$  How can I build intuition for what moments really are? I know they exist as a concept in physics and in mathematics, but I find neither directly applicable, especially because I don't know how to make the abstraction from the mass concept to a data point. The term seems to be used in a specific way in statistics, which differs from usage in other disciplines.  What characteristic of my data determines how many ($r$) moments there are overall?


Construct a Compact set of Real numbers whose limit points form a countable set

What do you think about this set?   K = 0 $ \cup$ {1/n : n $\epsilon$ Natural numbers}   It has one limit point which is zero, so it is countable and it is compact. Is this correct?   Also, do you have any ideas of compact sets that come to mind whom you can count there limit points, and they have a countably infinite amount of them?  Let G = 0 $\cup$ {1/n : n $\epsilon$ Natural numbers}   Let {$G_n$} Be a collection of sets Such that N $\cup$ {N + 1/r} For r = 1,2.3.... and N = 0,1,2......   Let me explain, you first start with N = 0. For N = 0 you calculate all the values of r. For N = 0 that will give you a limit point of 0. For N = 1, you do the same, and that should give you a limit point of 1, for N = 2 the same, so on and so on.   I don't know if wrote the proper notation for the set I'm envisioning, but I feel like it gets the job done. What do ya'll think? Also, can you guys think of any other ones?


I was trying to solve the following:  Given: $0 < a < b$ and $n>1$, prove: $$na^{n-1}(b-a) < b^n-a^n < nb^{n-1}(b-a)$$  I managed to get this far using the mean value theorem: $$a^n(b-a)<b^n -a^n<b^n (b-a)$$ Any idea how to continue?


Was Sidious already making the Death Star by the end of Episode III?

I ask this because at the end of the movie, you see Luke on Tatooine, Leia with Bail Organa, and then a decent portion of the Death Star already done as Palpatine & Vader look on. So it seems the station was already under construction during the Republic. Or was there just some random time gap between these scenes?  Here is the scene in question:


Foreign characters in translation: most go well, some go wrong

On my website (hobby project, not commercial) I have to manage around 8 different translations, that are provided by volunteers. I manage these translations in Google Sheets. These sheets are saved as CSV and read out by PHP whenever it encounters a string in need of translation. So far, it works flawless! :D [ me happy ]  To update these sheets, I have written a PHP routine that collects all the strings-to-be-translated and puts them in a CSV. I then import this CSV into Google Sheets again.  This works beautifully, except for a couple of characters per language. For example, in portuguese, the 'à' displays as the notorious lozenge-with-a-question-mark symbol,     Also chinese goes fine(!), except for one character:     I know there are many questions and answers on this subject here at Stackoverflow. After reading these questions, I discovered that my files were intitially written out as "Western MAC OS encoding". Now I added some BOM characters, and indeed, TextWrangler recognizes it as 'UTF 8', but warns me that the file is corrupt. Indeed, the suspicious characters also don't display well in TextWrangler either.  I also see references to a function called 'iconv', but that doesn't seem to have no influence.  I have the feeling I mis a crucial step. Would you people mind having a look at a piece of code and help me futher?         // Write the translations to a CSV file    $fp = fopen("languages/gsheet_$language.csv", 'w');   fwrite($f, pack("CCC",0xef,0xbb,0xbf));       write_csv($fp, array('key','translation','notes'));    foreach($rows as $cols){     array_walk($cols, "convert");     write_csv($fp,$cols);   }   fclose($fp);      }   function write_csv($fp,$row){   foreach($row as $key => $value){     $row[$key] = "\"$value\"";   }   fwrite($fp,implode(",",$row));   fwrite($fp,"\n"); }   The post  is very informative, but has a strong focus on the database. However, I found the origin of the problem to be in the fgetcsv function:


How can I bind arguments to a Python method to store a nullary functor for later invocation?  Similar to C++'s boost::bind.  For example:  def add(x, y):     return x + y  add_5 = magic_function(add, 5) assert add_5(3) == 8


How to add custom nodes as a Blender standard

So there's this website called Chocofur.com and the people behind it have created a custom node setup for cycles, that you can use to make basic shaders easily.   So I have downloaded their nodes from their website. The .zip file contained a .blend file which when opened only contained a single plane mesh with  a single material was assigned to it. Sure enough this "material" was simply all their custom nodes disconnected one after the other, some of them which you can see here:    Now the part where I actually make these nodes a part of Blender is where I get lost, how can I do this? I know it's something like making a group... but how do I use this feature?


In visual studio 2015, solution folder leads to a unsupported error

I am using visual studio 2015 community version and meet a problem. I created a solution folder, say "ABC", to classify projects. However, I got an error that The project 'ABC' is unsupported. Not sure what is the wrong.   Also when I created the solution folder, I could not find it in my solution folder in my file system. How can I create a folder in my file system automatically when I create a solution folder in visual studio?  Thank you.


Lightning: Bug in Lightning framework when using aura:renderIf?

I have a Nav component which contains the following:  <aura:renderIf isTrue="{!v.showAllProducts}">     <c:showAllProductsCmp/>      <aura:set attribute="else">         <c:showSelectedProductsCmp/>     <aura:set> <aura:renderIf>   On a button press, showAllProducts changes from false -> true, and true -> false.   What this does is allow a user to see all products and select them (this is done in the showAllProductsCmp component. The component simply uses <aura:iteration> to render all product objects.)  and then switch to see only the selected products with the option to unselect them (in the showSelectedProductsCmp component).   I can add and remove any/all products, and my code works as intended -- as long as there is at least one product remaining.  For example, I can add 4 products, remove 3, and it works perfectly.  As soon as I remove the last product in the showSelectedProductsCmp and then try to switch back over to the showAllProductsCmp, the app crashes and I get a javascript error:  Uncaught TypeError: Cannot read property 'childNodes' of null aura_proddebug.js:8364   This line is part of the Lightning framework. Specifically it is:  nextSibling = target.childNodes[calculatedPosition];   So the target variable is null and it crashes.  If I remove renderIf and set attribute="else" components and ALWAYS render my two custom components, everything works as it should and there are no errors -- even if I remove all products.    So I don't believe that there is anything wrong with my code, though I would be happy to be corrected :)  PS: This doesn't happen on all renderIf statements: I have quite a few of them in my code and all of them work except for this one. Which means that this is hard to reproduce, sadly.  [Edit] I guess I should note that this nav component comes after quite a few other renderIf components, so maybe Lightning struggles with more than a couple renderIf components.  Another person has a similar problem to mine, and s/he also has multiple renderIf statements before the one that finally breaks.   [Edit2] Here is how you can reproduce the error (I'm pretty sure): Create a new Lightning application and copy the following code (which contains a lot of renderIfs)  [Edit3] The previous example had an error that was my fault. I've made a new example that hopefully doesn't have an error that is my fault. :)  <aura:application > <aura:attribute name="isEmptyArray" type="Boolean" default="false"/> <aura:attribute name="testingArray" type="Opportunity[]"/>  <button onclick="{!c.fillArray}">Fill array</button> <button onclick="{!c.emptyArray}">Empty Array</button>  <div>     <aura:renderIf isTrue="{!v.testingArray.length > 0}">         <aura:iteration items="{!v.testingArray}" var="opp">             {!opp.name} <br/>         </aura:iteration>         <aura:set attribute="else">             Array empty         </aura:set>     </aura:renderIf> </div> </aura:application>   And then copy the following code into the application controller:  ({ fillArray:function(component,event,helper) {     var tempArray = [{'sobjectType': 'Opportunity', 'name':'One'},{'sobjectType': 'Opportunity', 'name':'Two'}];     component.set("v.testingArray", tempArray); }, emptyArray:function(component,event,helper) {     var emptyArray = [];     component.set("v.testingArray", emptyArray); } })   Click the "fill array" button, then the "empty array" button, then the "fill array" button again. Receive the error.


Why does randomQuestion[0] === $("#question3") evaluate to false?

` var questions = new Array($("#question1"), $("#question2"), $("#question3")) var randomQuestion = questions.sort(() => .5 - Math.random());  console.log( randomQuestion[0] ) console.log(  $("#question3") ) if ( randomQuestion[0] === $("#question3") ){ alert("same")} else { alert("unsame")} `   Why if  randomQuestion[0] === $("#question3") not work ? All condition still show alert unsame.


Changed "Secure Boot" and installed ubuntu  At startup, a purple screen, changing "Secure Boot" and the system is switched  "nomodeset" does not eliminate the purple screen  Install the drivers for the video card:  sudo apt-add-repository ppa:ubuntu-x-swat/x-updates sudo apt-get update sudo apt-get install nvidia-current   ...changing "Secure Boot" and i see on a black screen cursor to a crosshair  If not change "Secure Boot" will be purple screen


How can I install Unity 3D game engine for Ubuntu?

I wish to develop some games on Unity 3D game engine. I was unable to find the link to download the application. Can someone post the download link for Unity 3D game engine for Ubuntu and/or explain how to install it?


The wick of my tea candle was buried in wax. So I lit a piece of paper and stuck it in the wax. Now the wax is burning off the paper, as if that were the wick.  The wax itself wouldn't light on fire without a wick, yet clearly what's burning is the wax, since the paper would have long ago burned up. What's going in here?


What does "The following London stations are available for travel with the chosen ticket" mean?

I booked a train ticket to London Paddington with GWR. The booking confirmation however says London Terminals on top of London Paddington. Then there are words like this:     The following London stations are available for travel with the chosen ticket:      London Paddington (PAD)   London Blackfriars (BFR)   City Thameslink (CTK)   London Cannon Street (CST)   London Charing Cross (CHX)   London Bridge (LBG)   London Waterloo East (WAE)   London Victoria (VIC)   Vauxhall (VXH)   London Waterloo (WAT)      Travel is not permitted to any other London Stations with this ticket   Does this mean that I can travel to any of these stations with my ticket without paying anything extra? If this is true, what should I do upon my arrival at Paddington if for example I would like to go to London Bridge station? I have never been to any railway stations in London other than Paddington, but London Bridge would be closer to my destination.   My ticket is Super Off-Peak Return if this is relevant.


How to add /home/user/public_html as virtual host in apache - centos

In Directadmin (I used it before) when we create a reseller, a new user with a home directory was created and user could add domains in a home directory like /home/user/domains/example.com/public_html  How i can add /home/user/public_html as virtual host to apache web server? I want to config apache like direct admin to use home directory.  Im new on Centos 6.5 and i'm trying to config a web server. My OS is clear (no any configs, just DNS) and SElinux is disabled in /etc/sysconfig/selinux. I have one ip for my VPS.  Now my config for httpd is below.  <VirtualHost domain-1.com:80>     DocumentRoot /home/user/domains/domain-1.com/public_html     ServerName domain-1.com </VirtualHost>   When i add this config, i get forbbiden error in http://domain-1.com and http://server-ip  UPDATE I added the following code to apache conf.d but the error is alive.  <IfModule mod_userdir.c>     UserDir enabled user     UserDir public_html </IfModule> <Directory /home/*/public_html>         Options Indexes Includes FollowSymLinks         Require all granted         AllowOverride All         Allow from all         Order deny,allow </Directory>


Hardware RAID0: what happens when a drive fails?

With a hardware-based RAID0, what happens when a drive fails?  For example, on brand name servers like HP DL120G7 with HP P410, when running FreeBSD on a zfs with a zpool mirror, or DragonFly BSD with mirroring through HAMMER etc.  The following questions come to mind:   Will the data on the non-failed drive that is part of a RAID0 still be usable? Or do the controllers spread the RAID0 data between the drives in a pseudorandom manner? Would ZFS at all know how the data is spread between the drives for its mirror functionality to function properly? I've heard some controllers don't let you avoid a hardware RAID (with P410 being such); in such case, do they generally make an exception so as to allow RAID0 arrays of just one disc, instead of a common minimum of two? When the failed drive is replaced by a datacentre technician, would it affect the data on the drive that has not failed?


Prove $C[a,b]$ with norm $\Vert f\Vert=\left(\int\limits_{a}^b\vert f(t)\vert^2\right)^{\frac{1}{2}}$ is not Banach space

Prove $C[a,b]$ with norm $\Vert f\Vert=\left(\int\limits_{a}^b\vert > f(t)\vert^2\right)^{\frac{1}{2}}$ is not Banach space.   Banach space is complete normed space. We say complete normed space if every Cauchy sequence is convergent.  I have checked $\Vert f\Vert$ is norm. Now, I want to proof $C[a,b]$ is not complete under norm $\Vert f\Vert$, i.e. there exist Cauchy sequence which not convergent.  Now I confuse to choose the Cauchy sequence is not convergent. Can anyone give hint to choose Cauchy sequence is not convergent?


Why doesn't controlled impedance depend on track length?

High speed design noob here.  Resistance increases as wire gets longer, but I found in saturn pcb calculator the impedance depends only on track geometry and distance from plane.   Say for DDR3 single ended signals with controlled impedance, does a point to point long track (say 150mm) vs. a short track (say 10mm) have any effect on the signal quality?


What is the significance of a coupling capacitor in a common-emitter amplifier? What would happen if it is removed? What will be  the effect on AC amplifier gain on removing it?


how do I put the text on a new row under a paragraph? My code is the following:  \paragraph{Title} Some text, Some text, Some text, Some text, Some text.   Right now It ends up like:  Title Some text, Some text, Some text, Some text, Some text.  I want it to be like:  Title  Some text, Some text, Some text, Some text, Some text.     Regards


Understanding the Empty set and set theory via proof

This question has already been asked. see above link.


I wanted to create a new material using an image texture.  It worked fine, but then it suddenly turned purple.  Is there any switch that I might have accidentally turned on that causes this behavior?


After the word 'needed' or 'needs' is the phrase 'to be' required or optional?

My students (and some younger colleagues) are increasingly stating (verbal) and writing phrases as such:  "The operating system needed updated."  or "The application needs fixed."  I was of the understanding that the phrase 'to be' was required between the words needs or needed and the following verb.


Supremum of a functional on $C^1([0,1])$

I've tried to solve the following problem (1.1.30 from Berkeley Problems in Mathematics, no solution is provided therein), but I'm not sure if my solution is correct. I wanted to ask you for your opinion.   The problem: Let $S$ be the set of all real $C^1$ functions $f$ on $[0,1]$ such that $f(0)=0$ and $$ (*)\int_0^1f'(x)^2\mathrm{d}x\leq 1  $$ Define $$ J(f) = \int_0^1 f(x)\mathrm{d}x. $$ Prove that the function $J$ is bounded on $S$ and compute its supremum. Is there a function $f_0\in S$ at which $J$ attains its supremum? If so, give $f_0$.  My attempts: First note that for any $y\in[0,1]$, $\int_0^1 f'(x)^2\mathrm{d}x \geq \int_0^y f'(x)^2\mathrm{d}x$. Thus, using the Cauchy Schwartz inequality,  $$1\geq \int_0^y f'(x)^2\mathrm{d}x \cdot\underbrace{\int_0^1 1^2\mathrm{d}x}_{\geq\int_0^y 1^2\mathrm{d}x}\geq \left(\int_0^y f'(x)\cdot 1\mathrm{d}x\right)^2=(f(y)-f(0))^2=f(y)^2 $$ which implies that $|f(y)|\leq 1$. Therefore, $J(f)\leq|J(f)|\leq1$ so we have shown boundedness.  The rest is still a bit shaky:\ Now the supremum of $J$ on $S$ is attained when the equality in $(*)$ holds (why is that? I'm not sure I could show this). This is the case for $f_0(x)=x$. Now $J(f_0)=\frac{1}{2}$. My guess is that therefore $J(f)\leq \frac{1}{2}$ is the supremum and maximum.  Thank you for your suggestions.


I have instances of data that are composed of 6 attributes. Each attribute takes values between 1-10. Any instance has a utility calculated by some utility function:  Example: {1,1,2,5,5,2} , utility = 0.89  In some readings for these attribute values, undefined values may appear in the instance, I mark them as question mark '?'  Example: {1,1,?,5,?,2}  These question marks represents uncertainty in the instance.  How can I model this uncertainty in a statistical or mathematical way ?   Thanks


Why wasn't the young Palpatine (Darth Sidious) identified as a potential Jedi at birth?

As per      To hinder transgression, those who showed an aptitude for the Force were taken directly from birth (or soon afterward) to train in the Jedi Temple headquarters on Coruscant or at smaller Jedi Enclaves as Padawans.   Why was Palpatine, who was strong in the Force, not identified as a potential Jedi at birth?


Give the point set with a corner at the orgin $$M:=\{(x,y)\in \mathbb{R}^2 : y=|x|, x\in (-1,1)\}$$ with the subspace topology of $\mathbb{R}^2$, $(M,\mathcal{T})$ forms a Hausdorff 1-dim locally Euclidean space. Next if we can define a differential structure $\mathfrak{F}$, then $(M, \mathcal{T}, \mathfrak{F})$ will give us a smooth manifold.   Note the projection map $\pi$: $(x,y)\mapsto x$ is a global coordinate map of $M$, it is easy to check that it is a homeomorphism. With $\mathfrak{F}_0 = \{(M, \pi)\}$ we just define $\mathfrak{F}$ to be the maximal collection such that  $$\mathfrak{F} = \{(U, \phi) : \phi\circ \pi^{-1} \text{ and } \pi \circ \phi^{-1} \text{ are } C^\infty\}.$$  From the above definition, it is indeed a smooth manifold. Now if this is a manifold, when we talk about tangent spaces, how can we connect the tangent space at $(0,0)$ to the usual tangent line conecpt in calculus.


Why didn't Tony use E.D.I.T.H. against Thanos?

When Thanos and his army attacked Avengers HQ in Avengers: Endgame, E.D.I.T.H. was in existence because Tony   died in the battle  so he couldn't build it after the battle. Why didn't he use E.D.I.T.H. in the battle? I know that E.D.I.T.H. stands for Even Dead, I'm The Hero. It means that Tony built it to gift it to someone else through his will. But, Thanos' attack was an emergency situation. E.D.I.T.H.'s drones and missiles with coordinated intelligence could certainly prove useful against Thanos and his army. Why didn't Tony use E.D.I.T.H.?


Change URL in Web Address in Browser, but Don't Go There

I know that the following JavaScript code instructs the browser to insert the specified URL string into the address bar AND go there:  document.location.href = 'http://www.john-doe.com/';   However, what I want to do is to only change the URL that appears in the address bar, but don't actually go to that URL.  How can I do this?


Once a visa is issued, is there a time limit on when it has to be used by, i.e. How soon do you have to enter the UK after issue.


Both versions are stable but Linux distributions mostly contain 1.5 (CentOS 7.3 for example)  I think about compiling haproxy from source and providing RPMs for the servers I administer using [this][1] approach. I understand why distros with longterm support tend to support older versions of packages.   So I try to find the middle way between being on the bleeding edge when compiling haproxy on my own and having support and automatic updates through the package manager. haproxy 1.5 will be the next release that moves to "critical updates only", that made me think I better jump to a current release.  When I decide to use haproxy 1.5 and either make the automatic shift to 1.6 (or whatever other version) as soon as RHEL/CentOS decides to move: what will be the steps needed to migrate ? Is this just some minor modifications in the config file ? Or are there some "breaking" changes to be expected ?


Could you please help me understand why the verb "face" is used in the past, in the following sentence, not in the present although the first part of the sentence is describing a future situation? The sentence is : "You’re never going to run in the Olympics. It’s time you faced (up to) the facts." Appreciate you help.


How can I set a custom icon for a folder?

Some folders in my Home directory have special icons.    I would like to do something like this with a custom icon for a folder.


$\mu(A \cap I) \le a \mu(I)$ implies $\mu(A) = 0$?

Let $\mu$ be lebesgue measure on $\mathbb{R}$, $0<a<1$. If $\mu(A \cap I) \le a \mu(I)$ holds for any interval $I$, can I say $\mu(A)=0$?  I tried to construct a counterexample by considering something similar to cantor set but failed. Can anyone give some comments? Thanks!


I have a Samsung galaxy Y device. It's running Gingerbread stock rom, and I want to upgrade this to Jellybean. Is there any custom rom for Galaxy Y?


Are similar questions allowed on two sites?

Are questions which are basically the same sites allowed on on two Stack Exchange sites?    For example take a look at these two questions from Server Fault and Super User.   Server Fault   Super User    If yes, then is there a way to link them or for the search box to look across multiple sites?


Does anybody know what kind of font is written in this document?

I've been looking forward to know which is this kind of font in LaTeX. I've tried with these changes in my preamble document:  \renewcommand*\rmdefault{cmss} \usepackage{pifont} \usepackage{amsfonts}   But that doesn't work. I attached an image as I want to see in my pdfLaTeX document   Can anybody help me please?


error while loading shared libraries: libssl.so.1.1 (and libcrypto.so.1.1)

As you can see I'm missing libcrypto and libssl files. I locked out myself from my server after running apt-update and apt-upgrade, I'm running this from web console, because ssh nor any other program won't work because of missing SSL files.  I tried removing and installing apt install openssl so did libssl-dev and/or compiling own openssl from a distro. None of these create the needed .so files, I ran locate, those files are not present anywhere on the server. There's also libssl1.0.0 which cannot be reinstalled and removing it would cause removal of 700MB of packages that would literally kill server and delete all data.


How to prove the determinant of this matrix invoving two sets of numbers is greater than zero?

Suppose $0<a_1<a_2<\cdots <a_n$,$\lambda_1<\lambda_2<\cdots<\lambda_n$and \begin{align*} A=\left({a_i}^{\lambda_j}\right)= \begin{pmatrix} {a_1}^{\lambda_1}&{a_1}^{\lambda_2}&\ldots &{a_1}^{\lambda_n}\\ {a_2}^{\lambda_1}&{a_2}^{\lambda_2}&\ldots &{a_2}^{\lambda_n}\\ \vdots &\vdots&\ldots&\vdots\\ {a_n}^{\lambda_1}&{a_n}^{\lambda_2}&\ldots &{a_n}^{\lambda_n} \end{pmatrix} \end{align*}  Prove that the determinant of A is greater than zero,$\mathrm{i,e.}$ $\det A>0$.  It is easy to check that the assertion is true when $n=2$,for when $n=2$, \begin{align*} \det A&=\begin{vmatrix} {a_1}^{\lambda_1}&{a_1}^{\lambda_2}\\ {a_2}^{\lambda_1}&{a_2}^{\lambda_2} \end{vmatrix} ={a_1}^{\lambda_1}{a_2}^{\lambda_2}-{a_1}^{\lambda_2}{a_2}^{\lambda_1}\\ &=\exp\{\lambda_1\ln a_1+\lambda_2 \ln a_2\}-\exp\{\lambda_2\ln a_1+\lambda_1 \ln a_2\} \end{align*} Since $(\lambda_1\ln a_1+\lambda_2 \ln a_2)-(\lambda_2\ln a_1+\lambda_1 \ln a_2)=(\lambda_2-\lambda_1) (\ln a_2-\ln a_1)>0$,then the case for $n=2$holds.While about the general case for $n>2$,I have no idea. Can anyone help me?It's a homework.


I want a domain name for my website with the name sampletext.com (as an example, with sample and text being 2 words). I have the option of taking the domain names sampletext.com and sample-text.com, but my objective is that whenever someone searches either sampletext or "sample(space)text", my website should show up in the search. To fulfill this objective, do you think it is better to have sample-text.com as my domain name?


Should I put an article before "half" when talking about time?

I know that in context of time, if for example it is: 1:45 then I should say: "It is a quarter to two". But my question is about "half" in such context, for example, in case of 1:30. Should I say "It is a half past one."? I'm asking it because I didn't notice that people use this article in context of time.


2 balls falling hit the ground at the same time

There are 2 balls in a vacuum, next to each other but not touch. They are on the edge of a surface they will both leave the table at exactly the same time. One gets pushed harder than the other. The earth is completely flat. Apparently both balls will hit the floor at exactly the same time and even further be at the same vertical height from the floor at any point in time. How is this possible?  If you push the one ball much much much harder than the first so that it is going at a considerable speed 100m/s compared to 1m/s say. The balls can't possible hit the floor at the same time, right?  Now the earth is round. You hit the one ball so hard it goes into orbit the other ball just falls of the table straight down like before. As the one ball has gone into orbit it will never reach the ground. However the slow ball will reach the ground much faster. How can a rule be different? If it doesn't work at the extreme then it shouldnt work at all.


I'm a physics graduate and usually encounter with complex numbers in physics. For example, in electrical engineering, Why do we express capacitive reactance as an imaginary number..? Can't it be expressed as real, as we generally do?  Forgive me, if my question is logically incorrect, But I do want to know why "i" is involved..?


Group Velocity and Phase Velocity of Matter Wave?

In quantum mechanics, what is the difference between  and  of matter wave? How can it also be that phase velocity of matter wave always exceeds the speed of light?


What am I doing when I find the determinant? And where does the formula for it come from?

I am currently learning about Vectors in the equivalent of High School. I know how to compute determinants to find the cross product. However I do not know what it is exactly that I am doing. I tried watching the video by 3 blue 1 brown but it still does not explain to me a) How the formula comes about b) How it links to the cross product


how to create a new file in an immutable directory

I have changed the directory attribute immutable by chattr +i /testdir; but I need to create files in that directory.   Or is there any way that nobody can delete the directory but the owner can still write in that directory?


How can i install Android Studio in Ubuntu 15.04

I'm Not able to install Android Studio through Terminal, Please Suggest me right way to install Android Studio in Ubuntu 15.04 .


Difference between the "Field" and "Algebra"?

In many books in Measure Theory area the concept of "$\sigma-field$" was applied to define a new measure especially probability measure. I saw in some papers and books the concept of "$\sigma-algebra$" was applied to define the uncertain measure. Is difference between them?


When is $f=\left(\frac{\sqrt{p+4}}{1-p}-1\right)x^5-3x+\ln5$ decreasing $\forall\; x$?

When is $$f=\left(\frac{\sqrt{p+4}}{1-p}-1\right)x^5-3x+\ln5$$ decreasing $\forall\; x$?    Diffrentiating: $$f'=5\left(\frac{\sqrt{p+4}}{1-p}-1\right)x^4-3$$ If $f$ is decreasing, $f'<0$: $$5\left(\frac{\sqrt{p+4}}{1-p}-1\right)x^4-3<0\implies x^4<\frac3{5\left(\frac{\sqrt{p+4}}{1-p}-1\right)}$$ Since if $\left(\frac{\sqrt{p+4}}{1-p}-1\right)\to0^+\implies x^4<+\infty$, which holds forallx, So:$$p=\frac{3\pm\sqrt{21}}2$$which doesn't ply with textbook-answer, since it mentions an domain for p.


k-means implementation with custom distance matrix in input

Can anyone point me out a k-means implementation (it would be better if in matlab) that can take the distance matrix in input? The standard matlab implementation needs the observation matrix in input and it is not possible to custom change the similarity measure.


Can I have a user preference for the ISO 8601 standard date format for all dates/times?

I'd really like an option to show all dates as yyyy-mm-dd HH:mm. The existing multitude of various things based on the age is much less workable.  Probably, at least the three common formats for date are needed with a check box for 2/4 digit year and a character for the separator, including no character at all:  yy-mm-dd dd-mm-yy mm-dd-yy   along with the time formats:  HH:mm HH:mm:ss HH:mm xM HH:mm:ss xM   (where the x is either A or P).


Why is Ubuntu 18.04 halting after login since upgrade from 17.10?

I have an Acer Aspire VX 15 (Intel Core i7, NVidia Geforce GTX 1050, 32 Gb RAM, HDD 1Tb).  I had Ubuntu 17.10 installed and everything was working fine. Then I upgraded to Ubuntu 18.04 and now, after I login via GDM (in graphics mode) the system halts. It becomes completely frozen.  However, if I press Ctrl+Alt+F2, switch to text mode, and then login in the console, the system works fine (in text mode) and do not halt.  Does anybody else has a similar problem?  Do you know how to fix this or how I can diagnose the problem?


How do I write a script for moving just the 20 oldest files from one folder to another?  Is there a way to grab the oldest files in a folder?


Let  $A = \left \{ \sqrt[n]{n} \mid n \in \mathbb{N}\right \}$. I need to find and prove the infimum of $A$.  Because $n \in \mathbb{N},$ we can know for sure that $\sqrt[n]{n} \geq 1$. (Does that need a deeper proof?)  Then to prove that $1$ is the infimum, for $\forall \varepsilon>0$, I need to find a certain $n \in \mathbb{N}$ that makes $$\sqrt[n]{n} < 1 + \varepsilon$$  How do I "engineer" that $n \in \mathbb{N}$ ?  What's the trick? Raising $\sqrt[n]{n} < 1 + \varepsilon $ to the power of $n$ doesn't really help.


Image appear at start of the page before the text

I am writing my thesis for high school and i need to put an image after some text, but as i do as i always did with the \begin{figure} etc. it appear at the start of the page before the text I writed before, how should I solve this?


Automate file upload in FileZilla using a script

Consider:  D:\Program Files\FileZilla FTP Client\filezilla.exe -c 0/GG/DG/ -a "K:\YY\XXXXX\AAAA\BB\idS.txt"   This code doesn't work as it says:     "PATH NOT FOUND" K:\YY\XXXXX\AAAA\BB\idS.txt   However  D:\Program Files\FileZilla FTP Client\filezilla.exe -c 0/GG/DG/ -a "K:\YY\XXXXX\AAAA\BB"   just connects to the FTP site I wished without any file being transferred.  Why is it not working?


How To Apply and Understand the Generating Function for Number Partitioning

The function p(n) counts the number of ways a number can be made up of smaller numbers. For example, the p(5) = 7 because you can make 5 in the following ways:  1-1-1-1-1  1-1-1-2  3-2  3-1-1  2-2-1  1-4  5  According to Wikipedia, the generating function for this, counting the possible partitioning of a number, is as follows:    After much effort, I have been unable to make any sense of this, or contort it in such a way that it actually answer the question: what is p(n) when n = 1000?. There is a great deal about this expression that I do not understand. Please answer any of the following which, given your expertise, you can.   n is the argument of this function, the number for which we are counting the partitions. What is x here? Where does it come from? Same for k? What is the significance of k? Why does it go from 1 to infinity?  What is the significance of the small dot on the right side? We see the sign on the left "Sigma" so often, but the sign on the right (Big Pi) appears, at least for me, in very few places. Why is this? On the right we see that we get the product of the expression for every value of k from = 1 to infinity. How does this make sense? If we go from 1 to infinity, isn't the resulting value necessarily infinite? It is known that actually getting a series of numbers from a generating function can be non-trivial. Is it even possible to solve for p(n) using this equation? Or does it simply explain the pattern with no means of getting the numbers? How can this be implemented in a computer language, one that is general, and not math-based, for example in Python, or in JavaScript? Is it possible? Can you provide an implementation of this generating function in computer code? (See PS) What is p(1000)? How do you know? Generally, in solving generating functions, using a "Taylor series" is proposed as a possible solution. How would you explain this to someone who does not know what a Taylor series is? Is this problem even solvable without a deep knowledge of that subject? Is it correct to call this an "equation"? Or is a generating function fundamentally a different thing?   PS I am asking this question because it is my hobby. I am NOT in a university and asking you to do my work, NOR am I employed, either as a mathematician or otherwise. This is fun for me, and I hope answering it is fun for you!


How can this brightly colored yet gentle pastel-color effect be achieved?

I found this image on  and quite a few have this vivid yet pastel effect.   Can it be achieved in Photoshop or Lightroom?


How to pass a type to a generic method at run-time

I'm trying to figure out a way to pass a type into a generic function by only knowing the type name.  public void Main() {     string typeName = "string";     Test<typeName>(); }  public void Test<T>() {     // Do Work }


What’s the origin of the phrase “pay attention”? Did one have to pay monies for this historically?

Does the phrase “pay attention” imply there used to be a fee for performing said action? If so, how would this be collected? In other words is “paying attention” objectively observable and therefore taxable? I suspect this phrase dates backs to Stalinist Russia, but I could be wrong.


I thought it might be a good idea to exclude sudo at the beginning of commands from shell history, to prevent deleterious mistypes.  I would do this with a cronjob and sed, but was wondering if there were a more correct way of doing it (in zsh)?  PS to comments: Yes, maybe simply removing "sudo " is not so good.  But isn't it a bit troublesome that something like sudo dd if=/dev/urandom of=/dev/sdb could be executed with <c-r>d<cr>?  Maybe it would be a good idea to remove the "s", so that one would have to supply <c-a>s.


In python, how to find out how many sets of numbers in the sentences

For example, if there is a sentence "I have 8 pens and my friend have 7 pens" I know how to use  re.findall to extract the number and the outcome will be ['8', '7']. However, i want to figure out how many sets of numbers in the sentence, which the answer suppose to be 2. Can someone help me to do it? thank you


I have the following string:  '2017-08-15T13:34:35Z'   How to convert this string to object that I can call  .isoformat()?  someobject = convert('2017-08-15T13:34:35Z') someobject.isoformat()   How to implement convert()?


Decomposing a symmetric function into elementary symmetric polynomials.

It is stated that any symmetric function can be expressed in terms of the elementary symmetric polynomials. I am trying to do that for the following generating function:  \begin{equation} \prod_{1 \leq i<j \leq k} (x_{i} + x_{j}). \end{equation}  I can't quite seem to find a way to do this in general. I can see some kind of pattern though, involving the monomial symmetric functions, which are  \begin{equation} m_{(1,2)} = x_1 x_2^2 + x_1^2 x_2, \end{equation} and similarly for any $k$. The subscripted values in $m$ can be any integer.   I've shown that this can be done for the cases $k=1,2$ in which cases we get  \begin{equation} \prod_{1 \leq i<j \leq 2} (x_{i} + x_{j}) = (x_1 + x_2) = \frac{m_{(1,2)}}{\sigma_2^{(2)}}, \end{equation} \begin{equation} \prod_{1 \leq i<j \leq 3} (x_{i} + x_{j}) = \frac{m_{(1,2,3)}}{\sigma_3^{(3)}} + 2 \sigma_3^{(3)}, \end{equation} and for $k=4$ I get something in the form of \begin{equation} \prod_{1 \leq i<j \leq 4} (x_{i} + x_{j}) = \frac{m_{(1,2,3,4)}}{\sigma_4^{(4)}} + ?, \end{equation} which I cannot work out, at least not easily, though I will do the tedious calculation. (Is there a way to employ the monomial symmetric functions in mathematica somehow?)  Main question, is there already a known decomposition to this generating function? If so, what is it? If not, how should I go about making one? Or at least being able to determine it for values up to $k=6$.


why is the textarea no longer updated after a manual modification?

the textarea updates correctly but no longer after manual modification !!   $(document).ready(function() {   $('tbody').on("click", "td", function(a) {     $("textarea").text($(this).text());   }); }); <textarea rows='5' cols='33'></textarea>

       Bulgarie

       Cambodge

       Canada

       CMC Chili

       Chine


Disable "This type of file can harm your computer" nag in chrome

I don't want to see that Discard/Keep dialog when downloading a pdf file in browser.  I just want it to automatically save to my default location.  I'm using chrome on Ubuntu 13.04.


I want to add an event handler to a dynamically generated list. I need to prevent the default action on the list item, and just console log "clicked". An example of what I'm trying to do is below:    $("#make-list").click(function() {     var mainList = document.getElementById("the-list");     for(var i = 0; i < 6; i++) {         mainList.innerHTML += "
Click ME!
"     }; })  $(".the-list__link").on("click", function() {     e.preventDefault();     console.log("click"); });  <button id="make-list">MAKE LIST</button>

     These answers:        Explain that due to how the .click() event is delegated, to use .on() method. I'm doing that. Why is it not working?


I "accidentally" pushed a commit to GitHub.  Is it possible to remove this commit?  I want to revert my GitHub repository as it was before this commit.


JPG file is more grey than file in Photoshop

Hi I'm new to this forum and I have a question. I am a fashion design student and at the moment I am retouching some pictures from a photoshoot. I like the colors I have in Photoshop but when I save it as a JPG somehow it all turns a little flat and grey, instead of the lively colors it is supposed to have. I have made a screenshot of both pictures, you can see it here:   Photoshop is set to RGB mode and I am saving it as the highest quality JPG. I really hope someone knows why this could happen, because unfortunately Google hasn't given me any answers. Thanks in advance :)!


Converting from color to true black and white in ImageMagick?

I have seen how to convert a picture from color to grayscale .  However, grayscale is not black and white.    Simply put, if a field has color, I want to convert it to black.  All other areas should be white.  So, if a line 6 pixels thick is orange, the other thread's answer will turn the line gray.  The line should be turned solid black.  However, is there a way to convert anything of any color at all (not white) to black?    I am working with Engineering prints, and it simply needs to be black or white. Gray does not work, because certain color lines become “gray” lines.


Can European Children attend public or private school in the US?

My sister and nephews are coming to the USA to visit me for almost 90 days, and we would like my older nephew (6 years old) be able to go to school. We would like him to interact with other children and learn basic stuff. I am not sure if he could assist to any public or private school while they are visiting us. They are coming from Spain with the ESTA visa. Any information would be much appreciated.  Thank you.


Is there any Javascript function that can redirect to another HTML?

I gave an example of what I'm trying to do. Can it be done in any way?    function ClosingHTML(){     DoSomeClosingCSSTransition();     setTimeout(function() {         SendMeToAnotherHMTL();     }, 2000); }


Ubuntu server mapping to two domains independently?

I have a wordpress blog running on my Ubuntu server. I want it so:  domain1.com loads domain1.com in the URL bar domain2.com loads domain2.com in the URL bar   each of these domains points to the same server.   Currently, domain1.com redirects to domain2.com and I'm not sure why. I've setup ssl on the server using lets encrypt and each of the domains separately point to the proper IP address and DNS name servers. I'm not quite sure what causes the redirect.


I have an  ASUS X55A-SPD0204O laptop. The rest of the FN+Fx (where x = number) like sound + - mute, screen turn off, wireless etc. work perfectly.  The problem is with the 2 brightness keys. They just won't work. Any suggestions?


Command Line Tools beta 1 for Xcode 11.0 offered as an update in the current latest public release of macOS Mojave 10.14.5

I am running the current latest public release of macOS Mojave 10.14.5 (18F132) with the current latest public release of Xcode 10.2.1 installed.  When opening System Preferences app → Software Update, I am offered an update for Command Line Tools beta 1 for Xcode 11.0.      I am pretty sure that I am not currently enrolled into Apple Developer Program. Neither have I knowingly or unknowingly installed any developer/public beta software profile on my Mac.  Why is this beta release of CLI tools offered as an update? Should I install it? How do I remove it?


How do I print the name of generic classes in c#?

Is there a simple way to obtain the name of a class in c# including template parameters?  I.E  Print( new List<int>{ 100, 1001});    Produce one of the following outputs:  List<int> List<Int32> System.Collections.Generics.List<System.Int32>   one of the first 2 is preferrable, but Type.FullName is not a viable option. It is ways too verbose.  Too verbose result that is unwanted.  System.Collections.Generic.List`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=235hosehoue5h]]   Note I'm asking just for a shortcut if it exists. I'm no asking for a full implementation of such feature.


Explanation of Freeman Dyson's solution of the counterfeit coin problem

Freeman Dyson's paper, The problem of the pennies Math. Gaz., 30 (1946) 231-234, offers a solution to a counterfeit coin detection problem. I quote his solution of one case as follows. I would appreciate the explanation of the purpose the demarcation of clockwise and anticlockwise labels serves.  Identify a defective penny among a collection of $M$ pennies of identical appearance, knowing that the defective penny is of a different weight from the others, by the use of a pair of weigh In n operations of weighing, it is required to ident and to decide whether it is lighter or heavier than the others. Solution of the problem for $M=\frac12(3^n-3)$. Let the pennies be numbered from $1$ to $M$. Each penny is given a "label" consisting of its number expressed as a ternary decimal, with a sufficient number of zeroes placed at the beginning to make each label exactly $n$. Each penny is then given a second label obtained by subtracting its first label from the ternary decimal $3^n - 1= 2M + 2$. Each label of a given penny can be derived from the other by changing digits $0$ into $2$ and digits $2$ into $0$ while leaving digits $1$ unaltered. Every $n$-digit ternary decimal occurs just once as a label, except for the three consisting of one digit repeated $n$ times. A label is called "clockwise " if the first change of digit in it after the beginning is a change from $0$ to $1$ or from $1$ to $2$ or from $2$ to $0$; it is called "anticlockwise" if the first change of digit is from $1$ to $0$ or from $2$ to $1$ or from $0$ to $2$. Of the two labels of a given penny, one is clockwise and the other anticlockwise. We denote by $C(i, d)$ the class of pennies whose clockwise labels have $d$ for their $i$-th digit. A cyclic permutation of digits changing $0$ to $1$, $1$ to $2$, $2$ to $0$ in the labels of all pennies would simply transfer all pennies from $C(i, 0)$ to $C(i, 1)$, from $C (i, 1)$ to $C (i, 2)$, and from $C(i,2)$ to $C(i, 0)$; this shows that the classes $C(i, 0)$, $C(i, 1)$ and $C(i, 2)$ all contain the same number $\frac13M$ of pennies. The $n$ weighing operations are specified by the rule that at the $i$-th weighing the pennies of $C(i, 0)$ are weighed in the left-hand pan of the scales against the pennies of $C(i, 2)$ in the right-hand pan, the pennies of $C(i, 1)$ being laid aside. The result of the $i$-th weighing is symbolized by a number $a_i$ which we take to be $0$ if the left-hand pan sinks, $2$ if the right-hand pan sinks, and $1$ if the scales remain level. We consider the ternary decimal $$A = 3^{n-1}a_1 + 3^{n-2}a_2 + \dots + a_n.$$ It follows from the result of the $i$-th weighing that the defective penny either is heavy and has $a_i$ as the $i$-th digit of its clockwise label, or is light and has $a_i$ as the $i$-th digit of its anticlockwise label. Therefore after $n$ weighings the defective penny is determined uniquely as the penny one of whose labels is $A$, and it is heavier or lighter than the others according as this label is clockwise or anticlockwise. It is interesting to notice that the latter question will usually be decided by the first $2$ or $3$ weighing.


Is it possible to deauthorize all foreign usb by default?

I would like to reject unknown USB by default, and ask for a password to mount every time an unauthorized USB enters one of my pleasure holes. so for instance, all USB’s that are currently connected (keyboard, mouse, webcam etc) are allowed by default without problem. however if I plugin a new usb device, I want my system to automatically ask for my password before it gets mounted. is this possible? I found this;  however it’s from 2007 and I believe there should be a setting or program (usbguard?) to already do what I ask for. Question 2) Also I don’t understand the difference between a usb device and a usb interface? (somebody care to explain?) thanks in advance


While upgrading from 14.04 to 16.04, my /boot partition filled & the upgrade failed. I now lack a /boot/initrd.img-4.4.0-119-generic, which the upgrade was trying to create when it failed.  The system booted anyway. I'm afraid to reboot as things stand. /initrd.img points to /boot/initrd.img-4.4.0-119-generic, which doesn't exist.   What to do?


Incorrect figure numbering using TiKZ-Feynman

I am trying to use the TiKZ-Feynman package to create Feynman diagrams for a report. However when I try to refer to them by their figure number, it is not generating the number correctly in some cases. It may be something to do with the section or subsection in which the diagram is contained. I am using TiKZ-Feynman 1.1.0 and compiling with LuaLaTeX on sharelatex.  \documentclass[a4paper]{article}  % packages \usepackage[margin=2.75 cm]{geometry} % margins \usepackage{tikz} \usepackage[compat=1.1.0]{tikz-feynman}  \begin{document}  \section{Section 1} This is the first section, including correctly-numbered figure \ref{fig:first}.  % Figure 1 \begin{figure}[h]     \label{fig:first}     \centering     \includegraphics[width=0.8\textwidth]{figures/firstfigure.png}     \caption{Caption correctly numbered.} \end{figure}   \section{Section 2}  \subsection{Subsection 2.1}  Reference to a tikz-feynman diagram with incorrect figure number \ref{fig:second}.  \begin{figure}[h]     \centering     \label{fig:second}     \feynmandiagram [horizontal=a to b] {     i1 [particle=\(e^{-}\)] -- [fermion] a -- [fermion] i2 [particle=\(e^{+}\)],     a -- [photon, edge label=\(\gamma\), momentum'=\(k\)] b,     f1 [particle=\(\mu^{+}\)] -- [fermion] b -- [fermion] f2 [particle=\(\mu^{-}\)], };     \caption{Caption gives the correct numbering} \end{figure}  \end{document}   Specifically, it labels the first as 'Figure 1' both in the text and in the caption. For the second, however, the caption generates correctly ('Figure 2') while the reference in the text says 'Figure 2.1'.


JAVA - What are the differences between these?

There are two ways I know of to create Threads. 1.     Thread thread = new Thread()     {      @Override      public void run()      {       //do something;      }     };     Thread thread = new Thread(new Runnable()  {   @Override   public void run()   {    //do something;   }  });    What I am asking is that, are there any differences in these methods, like which one is more efficient regarding Memory usage, CPU usage (if there is any difference), etc.


Dual Boot Goes to Win8 Doesn't even Show Grub screen

This is NOT an installation problem question. I've had both op sys working fine side-by-side for a couple of weeks now. I'm using Ubunutu 12.04 64-bit.  This morning when I tried to switch from Win8 to Ubuntu, it just rebooted into Win8. No grub screen whatsoever. This is the 3rd machine I've had dual-booting & have never seen this, but then Win8 is a 1st for me & has thrown some pretty awesome blocks in the path to get to here. Atrocious op sys...  I'm assuming the ASUS updater did this yesterday. (ASUS R503U)  So, do I just put the Ubuntu disk in & reinstall grub?


new entity with entity metadata wraper and multiple collection fields, how set a first new collection field ?

I have one custom content. It contains a multiple collection field.  If I create a new entity (via entity_metadata_wraper), how can I set a new multiple collection field ?   by example :   $new_entity = entity_create('node', array('type'=>'custom content'); $new_entity_w = entity_metadata_wrapper('node',$new_entity); ... $new_entity_w->a_new_multiple_collection_field[0]->some_field->set('...'); //(1) doesn't work //$new_entity_w->a_new_multiple_collection_field[]->some_field->set('...'); //(2)doesn't work   Error for (1) :  Unable to set the data property some_field as the parent data structure is not set  Error for (2) :  PHP Fatal error : Cannot use [] for reading in /var/...  I didn't find...thank you for some help !


I found it difficult to understand what behind the story of black hole, I have did some research but have no sense what it meant. This question is really base on my curiosity, I want to learn and understand the meaning behind the black hole! Thank you!


Exclude regression constant from non-linear regression

For example, suppose I've data set and I want to perform a non-linear regression on the data set as follows: $Y=B_1e^{B_2 X} + B_3$ and I found that if I exclude $B_3$ the $R^2$ increased also standard error of the regression decreased, can I exclude $B_3$?


How to retrieve removable storage drive letter using C/C++

How can I get the removable drive letter so that I could create a path and copy data from PC to the removable drive?   Currently I'm using  _getcwd(buff,b_SIZE); MessageBox(buff); strncpy(Root,buff,3);   I have no problem if I run my software directly from the USB and it will returns to me either D: or E:, which depends on the availability I guess. But my problem is I have to run my USB program from the PC which is of course the PC's program installed in C drive, and therefore this _getcwd will give me C:\ drive letter.  That's why I'm looking for if there's a way to check the current removable drive letter instead.   This is the nearest I could find for my question:


What is the difference between property and public field

I have read msdn article about properties. They show that example of property:  // Declare a Name property of type string:     public string Name     {         get          {            return myName;          }         set          {            myName = value;          }     }   Then they say:      Once the properties are declared, they can be used as if they were   fields of the class.   What would be the difference if they just left:  public string Name;   If I had a field: private string name and wanted to have only getter? Should I declare  public string GetName(){return name;} or should use those properties somehow?    Could somebody tell me what is wrong with that example:   private int age;  public void setAge(int age){    if(age < 100)     this.age = age; }


Why does two dimensional array take only the last two input integers?

I have been programming for a while in Java and C++. However, I am trying to learn Python and I am trying to initialize a two-dimensional array in Python. Why does it take only the last two inputs?  I tried everything, but I can't understand why it is not working how it is supposed to be.     def prog2():         x = int(input('x> '))         y = int(input('y> '))         pole = [[0] * x] * y          for a in range(x):             for b in range(y):                 pole[a][b] = int(input('> '))          print(pole)     prog2()   When I define x and y as 2, and the following four inputs as 1, 2, 3, 4,  I expect the output to be [[1, 2], [3, 4]]. However I am getting [[3, 4],[3, 4]]  x> 2 y> 2 > 1 > 2 > 3 > 4 [[3, 4], [3, 4]]   Thank you for your patience and help. :) I am a novice in Python.


What word describes a word which by definition encompasses another?

Hopefully the title conveyed my request with clarity.  An example:  *     Egalitarianism encompasses feminism.   *  What word describes that relationship? Where the former contains the latter and more (in context to the question).


Find maximum radius of circle that will fit within an irregular polygon?

I have a problem which I think could be handled by using the  in the ArcGIS Spatial Analyst toolbox.  However I do not have a license for Spatial Analyst, so I am searching for an alternative; possibly using QGIS.  How do I find the maximum radius of a circle that will fit within an irregular polygon?  Note the polygon could be either a convex or concave hull (as shown below) and the solution must address both.    I tried  but unfortunately the result is not what I was looking for.  First, I do have very irregular polygons like this one:    If I follow Joseph's description the result looks like this:    This is for sure the result following that solution, but it is not the answer of my question.  Important for me is to answer the question how large the radius of a circle can be in maximum so that the circle is still completely inside the polygon, regardless of where the centre of the circle is.  For example, there is much more space in the north of the polygon, so that there can be placed a much larger circle than in the south of the polygon. But how large can this circle be?


Does it make sense to keep track of largest known prime?  In other words:  Are there any (more or less practical) situations, where we need the largest known prime? (except of the "situation" of searching of even bigger prime)


Background   hopefully (adverb): in a hopeful manner Presumably (adverb): used to convey that what is asserted is very likely though not known for certain. While fully acknowledging, as noted in , that hopefully is accepted in standard usage as a sentence modifier and as a ; I wonder about the etymology and more precise historical differences in the usage between hopefully and presumably.    Question based on background  Why is it correct to say:     "Presumably it is true..."      and incorrect to say       "Hopefully it is true..."    In other words, why would the latter sentence be corrected to:       "I am hopeful that it is true..."    which does not mean the same thing;  whereas the former could be changed to:     "I am presuming it is true..."   which does mean the same thing?    Put one other way, why is it standard (and I believe acceptable) English to assume an implicit verb when using presumably:      "I think presumably that it is true..."   where presumably is modifying the verb think to mean that the thought is one which is thought presumptuously or in a presuming manner.    Yet it is not accepted that "I think" is assumed as in:     "I think hopefully that it is true..."   Where hopefully is modifying the verb think to mean that the thought is one which is thought hopefully or in a hopeful manner.  Or is it the case that presumably is just as frequently misused as hopefully and that both are incorrect? If that usage of presumably outlined above is accepted as grammatically correct, is there some etymological reason for this usage?  Presumably someone must know the answer to this question. I await members' replies hopefully.


Why is selected item highlighted in Red?

I am new to Blender. I watched a few tutorials for Blender and I noticed that their selected objects are highlighted yellow. I try to copy the tutorials. I have only ONE object and I want to move that ONE object. When I select that ONE object it is highlighted in red. Wow, that is completely unexpected! I can't move or rotate the object. I want so desperately to do something as basic as moving an object. I suspect that the object does not move because it is red. I am so mad. Why is the selected object highlighted red?  The result of moving the cube the tutorial way.  No "Transform Affect Only" has been selected  Clicking on the yellow dot in the bottom left corner will highlight the cube red and clicking on the cube will do nothing.


How can I determine whether simple graphs with degree sequences 1. 5,4,3,2,1,1 2. 3,3,3,3,2,1,1 exist?

For both of these degree sequences have an even sum and they both have an even number of odd degree vertices. This is the only criteria I have learned for these problems for such graphs to exist. So the first one by this could potentially exist but it logically doesn't make sense because if you start with a degree 5 vertex and leave two of the connected vertices with degree one the we have six vertices there is no way to create the remaining degrees without increasing these other degrees right? To create a degree four vertex we have 3 free vertices to build off of but this would need to connect to one of the already established vertices. For the second sequence I think I have drawn a picture which satisfies the degree requirements with 7 vertices and 8 edges but this is simply through trial and error. Is there a way to formally prove that this graph exists and create it without having to just draw pictures until something works/doesn't work?


Reinstall of OS after CPU Upgrade needed?

I recently upgraded my CPU from an Athlon II X2 250 to the Athlon II X4 610E(45W 4 cores -- can't beat the efficiency).  Is an ubuntu reinstall required?


How to loop over a whole file 4 lines at a time?

I have a bunch of loops for calculations that I want to perform. I am calculating the average value of 4 lines in a file. However, I want to loop this calculation of an entire file with hundreds of numbers.   i.e.   2 5 3 7 3 1 4 6 2 4 3 2 ...   would give   4.25  3.5 2.75  ...   Can someone recommend a solution?


Is there an integer solution for $(x^x) + (y^y) =(z^z)?$

Is there an integer solution for $x^x + y^y =z^z?$ Is there an  approach to evaluate that if this question has a Yes or no answer. Computers are useless as figures become so big after few iteration.


I'm using a 2008 Mac Pro as a home media server, how to get Wake On Network Access to work?

I'm trying to make use of an old Mac Pro with 10.6.8 I had lying around as a wireless home media server, backed up with Time Machine.  I'm just using a standard Huawei router provided to me by my ISP. I've set up file sharing and screen sharing, so that I can access the files on the Mac Pro with my Macbook Pro. But is there a way that I can save power by having my Mac Pro constantly asleep, but wake up automatically when I want to access it from the Macbook Pro? Then go back to sleep once I'm done?  I've ticked the Wake For Access Network on my Mac Pro and Macbook Pro. But that doesn't work. I did some research and saw that you need an Airport or Apple TV with Bonjour Sleep Proxy to get it to work. Is there any way to get it to work with what just the Mac Pro and Macbook Pro?


Error in batch file to copy folder: 'Invalid number of parameters'

I am making a batch file in Windows XP to copy my folders I need to another folder on my PC. I am getting an error.  I get the error "Invalid number of parameters".  xcopy /s/z D:\Documents and Settings\%username%\Desktop C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\Favorites C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\Start Menu C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\My Documents C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\PrintHood C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\NetHood C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\Templates C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\Searches C:\SomeRandomFolder\ xcopy /s/z D:\Documents and Settings\%username%\Local Settings\Application Data\Microsoft\Outlook C:\SomeRandomFolder\ pause   Then I changed the batch and get this error: "File not found - Desktop"   xcopy /s/z D:\...\%username%\Desktop C:\SomeRandomFolder\ pause   How do I fix these errors?


maximum value of $6$ variable expression.

If $a,b,c,d,e,f\geq 0$ and $a+b+c+d+e+f=1\;,$ Then $\max(ab+bc+cd+de+ef)$   $\bf{My\;Try::}$ Using Lagrange Multiplier Method::  Let $$F=f(a,b,c,d,e,f) = ab+bc+cd+de+ef-\lambda(a+b+c+d+e+f-1)$$  $$\displaystyle \frac{dF}{da} = b-\lambda\;,\frac{dF}{db} = a+c-\lambda\;,\frac{dF}{dc} = b+d-\lambda\;,\frac{dF}{dd} = c+e-\lambda\;,\frac{dF}{de} = d+f-\lambda$$  and $$\displaystyle \frac{dF}{df} = e-\lambda\;,\frac{dF}{d\lambda} = -(a+b+c+d+e+f-1)$$  Now for $\max\;,$ Put all derivative $=0$  So we get $$a=\lambda\;,b=\lambda\;,c=0\;,d=0\;,e = \lambda\;,f=\lambda$$  Now put into $$a+b+c+d+e+f=1\;,$$ We get $$\lambda = \frac{1}{4}$$  So we get $$\max(ab+bc+cd+de+ef) = \frac{1}{16}$$  But answer given as $\displaystyle = \frac{1}{4}$  plz explain me where I am wrong, Help required, Thanks


Why is the fundamental group of torus with finitely many points removed a bouquet of circles?

I am looking for a full explanation for how to compute $\pi_1(S^1\times S^1 \setminus \{x_1, \ldots, x_n\})$ where each $x_i\in S^1\times S^1$. I know that this has been asked on SE before, but the answers are always brief sketches.  I think that the final answer comes out to the free product $\ast_{i=1}^{n+1}\mathbb Z_i$ where each $\mathbb Z_i=\mathbb Z$, but I have little idea as to how we arrive at this.  I would really appreciate it if someone could help me understand the full process of computing this fundamental group. It would also be great if the explanation could stick to relatively basic concepts (i.e., basic properties of free groups, Van-Kampen, etc.).  UPDATE (this is not a duplicate):   I realize that my question was too vague. Here is some more direction.   The answer should come out to a bouquet of $n+1$ circles, I believe. My intuitive ideas is as follows. The torus with one point removed deformation retracts onto $\mathbb Z \ast \mathbb Z$. Now, my justification for this is a little fuzzy, though. I can see that $S^1\times I$ deformation retracts onto $S^1$ where $I=[0,1]$, so that $\pi_1(S^1\times I)\cong \mathbb Z$, but I can't draw an explicit connection between this fact and the first deformation retraction. Any help seeing the explicit argument here is appreciated.   Moreover, I don't see in general how removing more points continues to add to the bouquet of circles. Would we need an induction argument? If so, how would it go?  I  hope this clarifies my question.


Why Json.parse keeps changing my interger value in a nested object

my obj = {     "formname": ["appname", {         "operation": ["add", {             "values": {                 "Activation_code": "12345",                 "ID": 722756000010586033,                 "game_Id": "10000"             },             "status": "Success"         }]     }] }   The above code is my object from a server I have no problem getting the value the point am making is why JSON.parse(obj) is changing the ID after  the object as gone through its function.  hence after a parse it spits back the ID as 722756000010586000 Why?


Getting "global name 'foo' is not defined" with Python's timeit

I'm trying to find out how much time it takes to execute a Python statement, so I looked online and found that the standard library provides a module called  that purports to do exactly that:  import timeit  def foo():     # ... contains code I want to time ...  def dotime():     t = timeit.Timer("foo()")     time = t.timeit(1)     print "took %fs\n" % (time,)  dotime()   However, this produces an error:  Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "<stdin>", line 3, in dotime   File "/usr/local/lib/python2.6/timeit.py", line 193, in timeit     timing = self.inner(it, self.timer)   File "<timeit-src>", line 6, in inner NameError: global name 'foo' is not defined   I'm still new to Python and I don't fully understand all the scoping issues it has, but I don't know why this snippet doesn't work. Any thoughts?


Receiving multiple notifications for the same badge

One of my answers on Ask Ubuntu meta reached the lofty heights of 25 upvotes and the relevant badge was duly awarded. However, I seem to keep getting the notifications:    Note that only the notification was received in triplicate. The badge was only awarded once.


How can I load an external JavaScript file using a bookmarklet?  This would overcome the URL length limitations of IE and generally keep things cleaner.


I discovered that the summation $\displaystyle\sum_{k=1}^n k\cdot k!$ equals $(n+1)!-1$.  But I want a proof. Could anyone give me one please? Don't worry if it uses very advanced math, I can just check it out on the internet. :)


I first started using Ubuntu on my laptop and decided also to install it onto my desktop. Where all the annoyance began. I did download the source from Ubuntu webpage, transferred the file via Rufus to the same Usb Drive which I used back when I properly installed Ubuntu on my laptop. But in desktop it does not boot. I do get into the Boot Menu, Select USB-HDD to install Ubuntu, but in every try it starts Windows all over again. So I did some research, changed the Primary Boot to USB from BIOS. Tried again and it is still opening Windows and furthermore USD-HDD does not appear on the top on Boot Menu. No other Usb is connected while attempting installation, I do everything by the book but it does not work. Hoping to find some answers. I was really getting used to Ubuntu on my laptop :( Thanks


Multiple definition of `Node::print()' in CodeBlocks

I'm trying to write a List class, but have a problem:     E:\junior_req\test_project\Node.cpp|6|multiple definition of `Node::print()'|   My code:   Node.h:  class Node {     Node* next;     int value; public:     Node() {next = nullptr; value = 0;}     Node(int t) {this->value = t; next = nullptr;}     Node(const Node& t) {this->next = t.next; value = t.value;}     ~Node() {}      int getValue() {return value;}     Node* getNext() {return next;}      void setValue(int t) {value = t;}     void setNext(Node* t) {next = t;}      Node& operator=(Node t);      void print(); };   Node.cpp  #include "Node.h" #include <iostream> using namespace std; void Node::print() {     cout << this->getValue() << endl;     if(this->getNext() != nullptr) this->getNext()->print(); }   List.h and List.cpp classes are same, but there are no errors.   Main.cpp:  #include <iostream> #include "List.h" #ifndef NODE_H #define NODE_H using namespace std; int main() {     cout << "Hello world!" << endl;     List l;     l.add(1);     Node* one;     l.add(one);     one->print();     return 0; } #endif // NODE_H   #pragma once doesn't help  What is wrong with my code?


What is it called when you say something but it does not imply for the other?

I'm really lost for words...  For example, I like people with short hair. But then someone could say, so you hate people with long hair? But, of course, I did not give any information on people with long hair. I could've liked/hate it. What is this called? I'm sure there was a name to this, maybe an expression?


How can I optimize Ubuntu for minimal energy usage? I use my laptop for development, but also for writing. I have a 9 hour flight coming up and a 6 hour battery life when already using   limited screen brightness no usb devices no networking bumblebee installed and the nvidia card switched off TLP set on powersave   How can I now increase my battery life knowing that I only want to write (using LibreOffice)? I essentially want a very minimal system for a sort of 'writing mode.'   Should I limit my quadcore to one core? Should I disable some services? Here is the list of service --status-all  [ + ]  acpid [ + ]  anacron [ + ]  apache2 [ - ]  apparmor [ ? ]  apport [ + ]  atd [ + ]  avahi-daemon [ ? ]  binfmt-support [ + ]  bluetooth [ - ]  brltty [ + ]  bumblebeed [ + ]  console-font [ + ]  console-setup [ + ]  cron [ + ]  cups [ + ]  cups-browsed [ - ]  dbus [ ? ]  dns-clean [ - ]  elasticsearch [ - ]  fancontrol [ + ]  friendly-recovery [ - ]  grub-common [ ? ]  irqbalance [ - ]  kerneloops [ ? ]  killprocs [ + ]  kmod [ ? ]  lightdm [ - ]  lighttpd [ - ]  lm-sensors [ ? ]  mysql [ ? ]  networking [ + ]  nmbd [ ? ]  ondemand [ - ]  openvpn [ + ]  postgresql [ ? ]  pppd-dns [ + ]  prey-trigger [ - ]  procps [ - ]  pulseaudio [ ? ]  rc.local [ + ]  resolvconf [ + ]  rfkill-restore [ + ]  rfkill-store [ - ]  rsync [ + ]  rsyslog [ + ]  samba [ + ]  saned [ - ]  selfcontrol [ ? ]  sendsigs [ + ]  setvtrgb [ - ]  smartmontools [ + ]  smbd [ ? ]  speech-dispatcher [ - ]  sudo [ - ]  timidity [ ? ]  tlp [ - ]  udev [ ? ]  umountfs [ ? ]  umountnfs.sh [ ? ]  umountroot [ - ]  unattended-upgrades [ - ]  urandom [ + ]  winbind [ - ]  x11-common    Should install a more lightweight desktop environment? Can I do this in a nice and clean way (after all I have my laptop nicely set up and do not want to have to reinstall before 14.04). Should I do something else?    One last thing: I would like to activate or deactivate all these options with one script (which I will run only when working on battery). Please be as kind as to include suggestions on how to do what you suggest.  PS: the info in some of the possible duplicates is dated for 13.10.


How to run Windows Steam games from Linux Steam (with WINE)?

I am currently using 2 versions of steam, the Linux one for games compatible with Linux, and the windows version in wine for games which are not compatible. I was wondering if it is possible to get wine to work on games in Linux steam (the one not using wine) , so I do not have to switch back and forth between the two steams.


I would like to ask how can I add the paragraph symbol § so that it will be displayed as below:          §4 First section          §5 Second section      By default it is generated as below when a \section command is used :          4 First section          5 Second section      Edit: Code below  \renewcommand{\thesection}{\S\arabic{section}}   is one solution but adds § also with \subsection command. Is there another solution?


Does the level prerequisite for Invocations refer to class or character level?

The level requirements for Warlock invocations stated in the PHB are refering to which level, character or Warlock class?  Example: If I multiclassed into Warlock, Monk6/Warlock2, would I be able to pick up One With Shadows as an invocation which carries a 5th level requirement?


I changed my hostname, why is my bash PS1 prompt unchanged?

I changed my hostname by editing /etc/hostname and can see the new hostname using the hostname and hostname -F commands.  But the shell prompt is still showing the old hostname.  This is Ubuntu 11.0.4 by the way. The prompt is set in my .bashrc which I have not edited. Logging out and even rebooting has no effect.  Relevant section of the standard Ubuntu .bashrc:  if [ "$color_prompt" = yes ]; then     PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ ' else     PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ ' fi   ($debian_chroot is unset as I login...)  I guess the hostname is picked up by the special character \h.  Here's the PS1 setting as reported in the shell:  PS1='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '   And here is what PS1 shows:  username@oldhostname:~$    I repeated the process using the exact command in Warren's answer. It turns out that the hostname works until reboot but then it is lost, even though /etc/hostname contains the new hostname.


SQL server database log full for application databases

We have an issue that our application database gets log full because we have a schedule job to write to a flat table for reporting purpose every hour in the application database. I wonder if we should create another reporting database, and write the data into the flat tables in reporting database, will it take care of the log full issue since we are now writing to a different database?


Why didn't Leia immediately return to her father on Alderaan as soon as she obtained the Death Star plans?

If I have the timeline right from A New Hope:   Leia's father sends her on a mission to travel to Tatooine to enlist the help of an old Jedi Knight, General Kenobi. The Rebellion needs his help! She is to bring Kenobi back to Alderaan, where her father awaits. On the way to Tatooine, Leia unexpectedly gets her hands on the detailed data plans of the Empire's new super-weapon, the Death Star. Wow! This could really help out the Rebellion, and may even be an essential piece of information for the survival of the entire Alliance! She CONTINUES to Tatooine to go enlist the help of General Kenobi, but just before she's able to land there, her ship is attacked by Imperial forces, led by Darth Vader. In a frantic, last-ditch effort, she puts the stolen data into a droid and records a message for Kenobi, telling him to get his butt to Alderaan and to make sure this R2 unit gets there with him. "My father will know how to retreive [the plans]."   ...then that was an awfully risky (and unlikely) choice Leia made, to continue on to Tatooine to find an old army budy of her father's, who she may or may not even be able to find.  Why didn't Leia immediately return to her father on Alderaan to deliver those precious plans? Why risk so much to continue on her original mission to recruit Kenobi?


I just upgraded Google+ to 3.6.0.44338848 (released late March 2012) and now it won't launch. It says:     This app won't run without Google Play services, which are missing from your phone.   If I tap "Get Google Play services" I'm brought to Google Play where I tap "install" and "accept and download" but then I get "Error: No connection."  (I do have a connection. I can browse the web just fine.)  Now, I should mention that Market/Play has been odd the whole time, I've had this phone, a T-Mobile myTouch 4G running Android 2.2.1. Whenever I want to install an app, I have to go into Applications, tap Google Play Store, and tap "Uninstall updates" to restore the Market app. Then I can install applications. Over time, some process upgrades Market to Google Play but I can't install applications until I downgrade to Market to avoid the "Error: no connection" message. The processes is frustrating. On my old LG phone (also running 2.2 Google Play worked just fine).  I'm been putting up with all this downgrading because it's not often I install apps and usually there's no problem after installing or upgrading an app.  But now the Google+ app is unusable so I'm motivated to do something about the "No connection" problem.  I've read through posts such as  and Google's help page at  but I'm stuck. Please help.


Run command 2 regardless of whether command 1 succeeds or not

I have cmd1 and cmd2.  cmd1 && cmd2 will not run cmd2 if cmd1 fails.  cmd1 || cmd2 will run cmd2 if cmd1 fails  How do I run cmd2 regardless of whether cmd1 succeeds or not?


Native speakers, how can you comment such a sentence:  I shall come, not will  Can I use it for  I will definitely come, not maybe    Adding some information other people asked me about.  How I came to such a question.  Here   I asked about "Shall I win?" pointing that it could have some variants of understanding:  1) Shall I win? = Should I win? (suggestion)  2) Shall I win? = Will I win? (archaic with 1st person)  3) Shall I win? = is it 100% that I will win? (predestination\inevitability)  The excellent guy Mixolydian said either variant was possible, that it didn't matter what person you used "shall" with, it could have this "predestination\inevitability" anyway. Out of this we're getting that nowadays we can use "will" for simple future actions and "shall" for almost predicted (almost 100% surety of happening) future actions.  If I want to say to someone:  Don't be afraid, I will come anyway.  Don't get panicked, I will definitely come  Be sure, I will come in any case  I can use "shall" for it meanining an action into which I will put 100% effort:  I shall come!  And what if my original sentence is  Don't doubt, I will definitely come, not maybe or probably  Can I use  I shall come, not will  pointing that "shall" guarantees me putting all my strengths into it while "will" doesn't give any assuarance that I will do everything to finally come.  As I understood, it wasn't very easy to ask such a question because English was different everywhere - US, UK, Australie, Ireland etc. I heard it was acceptabse to use even "thee\thou" in Ireland or somewhere like that while all other world has already forgotten such words...  P.S. What I got from the answers ias that it was better to forget about the existence of "shall" cause it created so many misunderstandings:D


I'm trying to make semantic urls for search pages, but if someone use a search finished in dot, the .net engine return a 404.   The request don't even get to the routing  engine, so i think its something related to security or something like that.   For example, the stackoverflow routes also don't work in these case: .


Does iOS support a built-in firewall like macOS does? I don't see anything about it in Settings.


Is a travel insurance necessary when transiting through Prague?

Because of price, instead of taking a flight to Berlin, I have had a flight to Prague booked, and will take a bus to Germany. I am aware that a travel insurance is necessary as a tourist in Czech Republic, or I will have to pay a fine, but is that also the case for entering the country? As far as I am aware we will not be staying in Prague; our time in Czech Republic will be 5 hours or less.


What version of iOS enabled Safari / native camera roll integration?

On macOS, there are music  integrated into the OS via standard file open API. , iOS  and third party apps. Web sites and Safari had use third party apps or custom JavaScript code to allow this. Which version of iOS enabled this natively?


Using Euler's Totient Function, how do I find all values n such that $\phi(n)=12$?

How do I generalize the equation to be able to plug in any result for $\phi(n)=12$ and find any possible integer that works?


can someone help me understand what's thecomplexity of this code? --Python

I helped someone with his homework, the request was to return the words of the string without duplicates, without using any methods or built-in functions. Obesely this code isn't efficient, but i wondered what is its time complexity. I thought it's O(n), but the opinions differ. Some said that it's O(n^2).  edit : guys i don't want to improve the code, it's not my homework. i generally ask what is the complexity what is the time and space complexity? and if you can explain your answer i'd appreciate it. string1 = 'asd asd dsa asd' list1 = [] temp = '' for i in string1:     if i == ' ':         if temp not in list1:             list1.append(temp)         temp = ''     else:         temp += i


Graphics: Tikz Picture Placed Incorrectly when Drawing Areas Between Curves

I'm trying to use the method outline in   to create a graph of the area between two curves to insert into a solution sheet. However, when I do, the box is placed incorrectly. The tikzpicture ends up way higher than it should be, rather than being in line, and so covers up text, or other pictures placed above it. My code is as follows:  \documentclass[11pt]{article}  \usepackage{tikz} \usepackage{pgfplots}  \usepgfplotslibrary{fillbetween} \usetikzlibrary{patterns}  \begin{document} The box for the tikzpicture appears to be much higher than it should be.\\ {\begin{tikzpicture}[scale=0.75] \begin{axis}[ xmin=0,xmax=5,     ymin=-1, ymax=6,         xtick = {-1,1},     ytick = {1,2,3,4,5,6},     axis lines=center,     axis line style = <->,         ticklabel style = {font=\small} ]  \addplot[name path=F,domain={0:5}] {x}; \addplot[name path=G,domain={0:5}] {(x-2)^2}; \addplot[pattern=north west lines, pattern color=gray!50]fill between[of=F and G, soft clip={domain=1:4}]; \end{axis} \end{tikzpicture}} \end{document}


Is there an accepted definition for "P for trend" or "P-trend"

So is "P for trend" the same in principle as a common-or-garden P-value, but in a specific application i.e. odds ratios?  And can P-value, P for trend, and P-trend be regarded as interchangeable conceptually, terminologically, and in terms of statistical significance (at least)?  A pointer to an appropriate and citeable reference would be most useful, particularly if it states any differences or confirms sameness.  Edit responding to whuber's moderation  @whuber - thanks, but wouldn't an exact duplicate at least mention the topic of my question. I can see no mention of 'trend' or 'P for trend' on that page you provided. If on the other hand you know that P for trend is the same thing, then is there a citeable reference you can provide? Just to be clearer it is the use of the word 'trend' that confuses me, not the use of letter 'P'.   Another edit responding to whuber's moderation  Sorry if my question was not well formed. In attempting to provide my own answer  in the hope of a confirmation, I think that the word 'trend' when talking about P-trend (e.g. for a reported result in the literature) sets the context as a P-value test for linear trend in odds ratio in logistic regression, against a categorical predictor variable. If that is correct, then this is described in standard texts as 'test for trend', in which case my copy of Kirkwood & Sterne provides a citeable reference. Hopefully this addresses whuber's concerns. Whilst the correct interpretation of P-value is very important, I was missing the context of logistic regression.


Is it possible to write (or even better, temporarily redefine) 7 so that it is always output with line in the PDF output? Something like  \newcommand{\7}{\sout{7}}   generates a line which spans the whole width of the character. The line should be about half of that (see the pic above).


A star shaped open set in $\mathbb{R}^n$ is diffeomorphic to $\mathbb{R}^n$

After googling this fact (which is used in Bott and Tu to show the existence of good covers of manifolds) I've gotten the impression this is somewhat difficult to prove.  But I also came across this homework problem (problem 0) with a hint:    which gives me the impression that it is maybe not so difficult as I thought.  If anyone has any thoughts about how to prove this result I'd be very appreciative. Thanks for your time.


How to find and replace a particular string by increasing its numerical part?

My input file is,  ami41 ami56 ami23 ami67 ami45 ami34 ami88 jama66 tumi234 bichi23455 susami345   Using a single command line I need the output as,  ami42 ami57 ami24 ami68 ami46 ami35 ami89 jama66 tumi234 bichi23455 susami345   I used the command,  perl -pe 's/(\d+)/$1+1/eg' inputfile   But I got the output file as,  ami42 ami57 ami24 ami68 ami46 ami35 ami89 jama67 tumi235 bichi23456 susami346   i.e. all numerics with all types strings are increased. But I need the numerical only with ami string to be increased. Could anyone kindly suggest me some better command line.


Why can't I kill a SIGSTOP'd process with a SIGTERM, and where is the pending signal stored?

I am using Debian stretch (systemd). I was running the rsyslog daemon in foreground using /usr/sbin/rsyslogd -n and I did a Ctrl+Z to stop it.  The state of the process changed to Tl (stopped, threaded). I issued multiple kill -15 <pid> commands to the process, and the state of the process was the same: Tl. Once I did an fg, it died. I have 3 questions.   Why was the SIGSTOP-ed process not responding to SIGTERM? Why does the kernel keeps it in the same state?  Why did it get killed the moment it received the SIGCONT signal? If it was because of the previous SIGTERM signal, where was it kept until the process resumed?


How to create a site in a sitecollection on a remote SPServer using C#

I am currently trying to write a Dynamics CRM 2011 plugin that creates a new SharePoint 2010 site (within an existing site collection) for every account that is created. I have the code for creating a library, which uses the following methods:          private static ClientContext CreateSharePointConnection()         {             try             {                 Uri spSiteUrl = new Uri(Constants.SharePointSiteName);                 using (ClientContext spcontext = new ClientContext(spSiteUrl))                 {                     spcontext.Credentials                         = new System.Net.NetworkCredential(Constants.UserName                             , Constants.Password, Constants.DomainName);                     return spcontext;                 }             }             catch (Exception ex)             {                 throw new Exception("SharePointMethods.CreateSharePointConnection (General Exception: "                     + ex.Message + ")");             }         }  private static void CreateDocumentLibrary(ClientContext _clientContext             , string _documentLibraryName, string _documentLibraryDescription)         {             try             {                 Web web = _clientContext.Web;                 _clientContext.Load(web);                 _clientContext.ExecuteQuery();                 ListCreationInformation lci = new ListCreationInformation();                 lci.Title = _documentLibraryName;                 lci.Description = _documentLibraryDescription;                 lci.TemplateType = 101;                 List newDocumentLibrary = web.Lists.Add(lci);                 newDocumentLibrary.ContentTypesEnabled = true;                 newDocumentLibrary.Update();                 _clientContext.ExecuteQuery();             }             catch (Exception ex)             {                 throw new Exception("SharePointMethods.CreateDocumentLibrary('" + _documentLibraryName                     + "') (General Exception: " + ex.Message + ")");             }         }   So I would like to write a method CreateSite instead of CreateDocumentLibrary. However, all examples I can find on the web for programmatically creating a Site are using SPSite, SPWeb, etc. Something like this:  private static void CreateSite(string _siteName, string _siteDescription) {     try     {         SPSite site = new SPSite(Constants.SharePointSiteName);         SPWeb web = site.OpenWeb();         SPWebCollection wc = web.Webs;         string siteTemplate = web.WebTemplate;         wc.Add(Constants.SharePointSiteName, _siteName, _siteDescription, 1043, siteTemplate, true, false);     }     catch (Exception ex)     {         throw new Exception("SharePointMethods.CreateSite('" + _siteName             + "') (General Exception: " + ex.Message + ")");     } }   However this is NOT a solution for my problem, because the SPSite, SPWeb, etc. only work on the local machine and I want to create a Site from a remote (in my case CRM) server. Anyone got an idea how to solve this.  PS: Code might still contain memory leaks, so please be carful when you use it for production purposes!


Should we explicitly repeat the content of the title in the question?

Shouldn't it be mandatory for the question body to actually contain the question irrespective of the fact it is mentioned in the title?  It has happened several times that I go through a question, and after reading I ask myself "what's the question?". The title usually goes into volatile memory and if the question contains a long description by the end the reading it evaporates.


I want to factorize $x^5+ax^3+bx^2+cx+d$ if $d^2+cb^2=abd$ but I don't know how to use the second equality.I tried a lot but I cannot know how to use it for example it is $d^2$ but we have $d$ and if we calculate $d$ using that equality it would be harder.Any hints?


Why are the axes in Minkowski diagrams swapped when comparing with diagrams in classical kinematics?

In diagrams in classical kinematics, the time coordinate $t$ is drawn horizontally and the spatial coordinate $x$ is drawn vertically.  Why are Minkowski diagrams drawn the other way round?  In classical kinematics, we like to picture position as a function of time, so having time on the horizontal axis in a diagram simply corresponds to the usual way we draw the graph of a function.  I get that in relativity, position and time are on equal footing, so that the functional aspect may be deemphasized. But since it is a pretty big hurdle to compare relativistic kinematics to classical kinematics if we always have to flip the diagrams in our heads, I would expect that this would be only done if there are some striking advantages. However, I couldn't think of any.  What's even more strange is that we still write vectors as $(ct,x)$ instead of $(x, ct)$. So we are also making it harder to apply visual intuitions based on the usual conventions in linear algebra (like picturing the action of a familiar matrix on a vector). Maybe the conventions in linear algebra are actually more recent than the conventions of special relativity.  edit: Although the other question has an accepted answer, it does not answer the question of why the convention from classical kinematics was discontinued. It simply reiterates that it is a convention (and a comment expands that this convention can be traced at least to a 1909 paper by Minkowski himself).


How is the authenticity of Debian packages guaranteed?

What security systems and processes are in place to prevent malicious third parties from hacking/compromising the security of code in the Debian mirrors, or to verify that the packages we get are in fact the ones the maintainers think they are?


I want to shade the heading of my table. It all worked fine until I started using \cmidrule. This is my output:    Is there a way to shade the white space between the first and second row?  The code below redefines the toprule and midrule commands to account for the heading's shading.  \documentclass{article}  \usepackage{booktabs} \usepackage{xcolor} \usepackage{colortbl}  %%%%%% Set up the coloured tables %%%%% \colorlet{tableheadcolor}{gray!25} % Table header colour = 25% gray \colorlet{tablerowcolor}{gray!10} % Table row separator colour = 10% gray \newcommand{\headcol}{\rowcolor{tableheadcolor}} \newcommand{\rowcol}{\rowcolor{tablerowcolor}}  % The top-most line of a table \newcommand{\topline}{\arrayrulecolor{black}\specialrule{0.1em}{\abovetopsep}{0pt}%     \arrayrulecolor{tableheadcolor}\specialrule{\belowrulesep}{0pt}{0pt}%     \arrayrulecolor{black}}  % The line between the headings and the table body \newcommand{\midline}{\arrayrulecolor{tableheadcolor}\specialrule{\aboverulesep}{0pt}{0pt}%     \arrayrulecolor{black}\specialrule{\lightrulewidth}{0pt}{0pt}%     \arrayrulecolor{white}\specialrule{\belowrulesep}{0pt}{0pt}%     \arrayrulecolor{black}}  %%%%%END: Set up the coloured tables %%%%%  \begin{document} \begin{tabular}{ccc} \topline \headcol      & A & B\\ \cmidrule{2-3} \headcol Blue & Red & Yellow\\ \midline 1 & 2 & 3 \\ \bottomrule  \end{tabular}  \end{document}


Connected metric spaces with at least 2 points are uncountable.

That's a problem I proved (quite a while back) in tiny Rudin. However, I don't really get it. The other questions were actually useful results - I don't think I've ever come near using this result. Surely it's going to be close to apparent that you're working in an uncountable set?  For instance, examples where this result could be applied but it is hard otherwise to tell that the space is uncountable?


What does the word 'it' refer to in the following sentence:It is dark outside?


If a user upvotes answers to a question and I have multiple answers there, it is hardly serial voting

Today I had "serial upvoting" reversed and lost 40 rep. But it is hardly can be called serial voting: seems that a user was voting for requests he liked in  and also voted for 4 of my 17 (yeah, I have many :D) feedback-answers to this question. It would be conspicuous if the user would vote all the 17 of my answers, but he didn't (and even in this case it is one question, so theoretically, a user can vote all the answers, but can just run out of votes if there are more than 40 answers).  How can it be serial voting?  It was reversed today and therefore I have rep capped at just 160 :(


Ok, so I'm kinda new to Linux but can usually problem solve and fix these things on my own. This time... yeah, I'm going to need some help. I've been trying for a while now and have looked at many different pages trying to fix this small problem. So, I've tried using blueman but have failed to get them to pair. I also tried to do "ControllerMode = dual" and the other options there but have gone nowhere. I also tried to do it through bluetoothctl and have gotten nowhere either. I can provide my system info if needed. Laptop Model: Alienware 14 p39g001 Thanks for any help!


I have never used this software before. My dad unexpectedly passed away one week ago today. His computer is locked. Me and my siblings want to gain access to see if there are pictures, any last words, letters anything. How can we unlock without a password? Can we at all? Who would I even go to about it to try? I’m lost and just looking for answers.


Git applies changes to master branch when on other branch

I have a file on master branch, I have then created a new branch new and wrote a few print statements. I then checkout onto master, and the same changes are on master aswell. I have not pushed the changes from new. How is that possible?


I'm teaching myself Python and my most recent lesson was that , and so I've just spent a while turning all my Class methods into functions.  I now realise that I don't need to use Class methods for what I would done with static methods in Java, but now I'm not sure when I would use them.  All the advice I can find about Python Class methods is along the lines of newbies like me should steer clear of them, and the standard documentation is at its most opaque when discussing them.  Does anyone have a good example of using a Class method in Python or at least can someone tell me when Class methods can be sensibly used?


I'm still experimenting with some OpenGL in LWJGL, and as I get to know more and more about OpenGL, I start to do more complicated things like multi texturing, shadowmapping and more. Now, right now I'm using the src folder (src/res) for my resources, and use src/resourcename in my code. When I export it, this won't work on another location as the relative path is ofcourse incorrect. What would be the best way of deploying your game with all the resources in one file? Maybe put the files in the jar?  I would like to hear from a few people how they store and deploy their project with resources, thanks!


Can not switch Node.js to a default version of my choice

When I run nvm alias default 12.8.0 I get this:     default -> 12.8.0 (-> v12.8.0)   But when I run node -v, I get v11.9.0 instead  Why is this happening ?


Can you iteratively import python modules?

Say I have some python modules:  mymodule1.py mymodule2.py mymodule3.py mymodule4.py ...   Can I iteratively import them?   This attempt doesn't work.  for x in range(1,5):     mymod = 'mymodule' + repr(x)     import mymod   Also, is there any reason why doing this is ill-advised?


Find all $k$ such that $x^p+k$ is reducible over $\mathbb{Z}$.

Let $p$ is a prime number.  Find all $k\in\mathbb{Z}$ such that: $x^p+k$ is reducible over $\mathbb{Z}$.  When $p=2$, it is easy to see that $k=-a^2, a\in\mathbb{Z}$.  When $p>2$ i think the answer is $k=a^p, a\in\mathbb{Z}$ but i don't have any ideas to approach this problem.  Any suggestion?