What exactly does "already" mean when used in the imperative mood?

This is a question about American English usage of the word "already". As a UK resident I don't completely understand when I hear Americans give commands like "Stop it already!" In the UK the word already is not normally used in the imperative mood and the sentence I've just quoted would leave an English person thinking "If you're saying I've already stopped it why are you asking me to stop it again?"


Clustering based on max distance between ALL points in QGIS

I'm working on a layer of thousands of points, some of points are very close together.  I want to group them into clusters according to the following rule: "The distance between all points within each cluster must not exceed 500m".  I can do it  with symbology (distance : map units (500m)).  But how to assign a cluster to each point within the attribute table?


Odd Corollary in Baby Rudin Chapter 2, Question 28

I've finished all the questions in Chapter 2 of Principles of Mathematical Analysis by Walter Rudin (self study), but I have a question about Q.28, which reads:     Prove that every closed set in a separable metric space is the union of a (possibly empty) perfect set and a set which is at most countable. (Corollary: Every countable closed set in $\mathbb{R}^k$ has isolated points.)   It's easy to answer the question, given what's proved in Q.27, but the corollary is a bit weird. It looks to me as though it is just an immediate consequence of the fact that non-empty perfect sets in $\mathbb{R}^k$ are uncountable, which is proved in the main text. I don't see what it has to do with what is proved in this question.  Given how meticulous the book is, I suspect the apparent non-sequiteur means I'm missing something.


Why String.Concat returns 'True' instead of 'true' (the same with false)?

I'm studying boxing and unboxing topic from C# 5.0 in a Nutshell by Joseph Albahari and Ben Albahari. Copyright 2012 Joseph Albahari and Ben Albahari, 978-1-449-32010-2, but I need to extend the deep of knowledge and I found the MSDN article: , on it I found this example code (evidently not intrinsically related to the main topic):  Console.WriteLine (String.Concat("Answer", 42, true));   Once executed it returns:  Answer42True   Why this is happening with the literal 'true' (the same occurs with 'false')?  .  Thanks in advance.


A possible inequality related to binomial theorem (or, convex/concave functions)

Let $x, \ y, \ p$ be any real numbers with $x>0$, $y>0$, and $p>1$.   The question is about (most probably) an elementary inequality:  Is it always true that  $x^p+y^p\leq (x+y)^p$ ?  Note that if $p$ is any positive integer, then the above inequality is obviously correct. What about if the number $p \ (\text{with} \ p>1)$ is any non-integer real number?  I guess that (by my intuition) the answer should be positive. But how can we proceed to prove this inequality?


Spoilers for The Last Jedi:      Just before Snoke is slain,   he narrates Kylo Ren's thoughts/feelings (saying things like "he turns the lightsaber towards his enemy" and so on) we see the Skywalker lightsaber being manipulated through the Force to point towards and then slay Snoke. My question is, do we know for sure who was using to Force to use the Skywalker lightsaber in this scene?   It could have been   A) Kylo Ren was turning igniting the Skywalker lightsaber with the Force. Snoke assumed the thoughts/feelings he was sensing were directed at Rey but they weren't.   Or... B) Snoke was so preoccupied with Kylo's thoughts that he wasn't paying any attention to Rey's thoughts. Rey takes advantage of this and uses the Force to turn and ignite the Skywalker lightsaber to slay Snoke. This option is reinforced by the fact that  1) the Skywalker lightsaber then zooms into Rey's hand, not Kylo's.  2) after the ensuing scuffle, Kylo Ren reveals that he hasn't switched sides; he is still a believer in the First Order.  3) Kylo Ren even tells Hux that Rey slew Snoke.


let $f(x)$ is continuous on $[a,b]$,and such    $$\int_{0}^{1}x^kf(x)dx=0,k=0,1,2,3,\cdots,n$$   show that: there exsit $n+1$ different $a_{1},a_{2},\cdots,a_{n},a_{n+1}(a_{i}\neq a_{j},\forall i,j\in[1,n+1])\in [a,b]$,  such that $$f(a_{1})=f(a_{2})=\cdots =f(a_{n})=f(a_{n+1})=0$$  It is easy to prove $n=1$, Let $$F(x)=\int_{0}^{x}f(t)dt,F(0)=F(1)=0$$ and $$\int_{0}^{1}xf(x)dx=\int_{0}^{1}xdF(x)=xF(x)|_{0}^{1}-\int_{0}^{1}F(x)dx=0$$ so $$\int_{0}^{1}F(x)dx=0$$ so there exsit  $\xi\in(0,1)$ such $F(\xi)=0$ so $$F(0)=F(1)=F(\xi)=0$$ so $$F'(\eta_{1})=F'(\eta_{2})=0$$ so $$f(\eta_{1})=f(\eta_{2})=0,\eta_{1}\neq\eta_{2}$$ so it prove by done,But for general,I can't  because I can't comment, Paramanand Singh,Hello,I read your solution, and you $d=e$ is possible,so I think your methods have some problem


How can I secure an Ethernet-over-power network?

I just bought myself an Ethernet-over-power adapter, and plugged it in. It seems to be working great, but now I'm concerned that my neighbours may be able to access my network.  I live in a rowhome complex; is it possible they can access my network? If so, how can I secure it?


Minimum value achieved by a specific integral

Suppose $f:[0,1]\to \mathbb R$ be integrable such that $\displaystyle\int_{0}^{1} f(x) dx = \int_0^1 xf(x) dx= 1$. Define $\displaystyle I= \int_0^1 f(x)^2 dx$ Then find the minimum achieved by $I$. Progress - I think it is $3$, but the answer states something else. Here is the approach- We use CS. $\displaystyle \Big(\int_0^1 f(x)^2 dx\Big)\Big(\int_0^1 x^2 dx\Big) \geq \Big(\int_0^1 xf(x) dx\Big)^2$. This gives $I \geq 3$. This is not the given answer as said and I don't see other approaches other than the CS inequality, as we know nothing about the function. Thanks for your time.


Why is pdflatex not recognizing my > symbol?

I have a > symbol in my LateX file. Specifically, I have the sentence: Say I have n > 1 apples.  When compile my .tex document using pdflatex, I get a pdf with an upside-down question mark in place of the > symbol. I checked this math guide for TeX and saw no special markup for >.  What is going on?


Why is my System is using a lot of memory

Can anyone tell me why my system is using roughly 2000 or more memory when I have no big applications open, the only things open on my computer is Skype and google chrome. Also it says its at 96% but i have 8000MB and all together it doesn't look like it can be higher then 3000. I have already tried restarting my Computer and scanning for malware  Windows 10 64 bit OS


Number of permutations when $1$ does not immediately precede $2$ ...

How many permutations of     $\{1,\ldots,9\}$ are there such that $1$ does not immediately     precede $2$, $2$ does not immediately precede $3$, and so forth up     to $8$ not immediately preceding $9$? One obvious example of such     a permutation might be $987654321$, but there are many others,     such as $132465879$ or $351724698$.}  Ok so I know the total number of permutations with no restrictions is 9!, but I'm not sure how to calculate it when the numbers have to precede each other. Thanks in advance for any help.


Can I use Likert scale data to do parametric statistical procedures such as linear regression and ANOVA? I've read that you can use Likert data in parametric analysis but in certain circumstances. Which are those? My independent variables are Likert items and my dependent variable is the mean score of a Likert scale. Also, I have 90 samples.


Why is it that if $[L:K]$ is finite, then $[L:K]$ is algebraic?

If $[L:K]$ is finite, then $[L:K]$ is algebraic.  The author's proof is to simply state that given $[L:K] = n$, then ${1, x, x^2, ... , x^n}$, for any $x$ in $L$, would contain $n+1$ elements, so it must be linearly dependent over $K$.  First of all, why must ${1, x, x^2, ... , x^n}$ be linearly dependent over $K$? I do undertsand that if $L=K(a_1, ... , a_m)$, and we pick an non-algebraic $a_i$, then ${1, a_i, a_i^2, ... , a_i^n}$ would be, by definition, linearly dependent over $K$. But how can we know that this works with all the elements in $L$?  Second of all, even if we find that $c_0+ c_1x+c_2x^2 + ... + c_{m-1}≠0$, for some $x$ in $L$, $c_i$ in $K$, why would this mean that $[L:K]=∞$?    I asked this question a couple days ago, though I didn't explain my doubt in such detail as in this post. Anyway, the replies asked if I understood the meaning of being 'linearly dependent over a field $F$'. My understanding is that a set ${b_1, ... , b_n}$ is linearly independent over $F$ if each element in $F$ can be written as $f_1b_1+...+f_nb_n$ (so that  the different combinations of $b_i$ form the whole $F$) and that the only way $f_1b_1+...+f_nb_n=0$ is for all the $b_i$ to be $0$ (so that we make sure all the elements in the set are needed to map create $F$).  I guess they asked me that question because is rather obvious why the author's proof works. Yet I don't know why, but it isn't that obvious to me.    I would really appreciate any help/thoughts.


Proving that the estimate of a mean is a least squares estimator

I think this is a really simple question so please bear with me -- I just had my first class in regression and I'm a little confused about nomenclature/labeling.  Does anyone recommend some good weblinks that explain beginning linear regression really well?  There's a question I've been looking at for a while and I'm not sure how to do it (although I'm sure the solution is simple):  Show that the sample estimate $\hat{\mu} = \bar X = \frac{1}{n} \sum X_i$  is a least square estimator of $\mu$ for a variable $X$ given $X_1, \ldots, X_n$.  My first thought was,  $$SSE = \sum (\mu - \hat{\mu})^2,$$  but I'm not sure if that's right. I'm confused about what the $\beta$ is (is it $n$?) and I don't know if there are enough parameters to expand it.   Thanks so much for your patience and if this doesn't make sense, I can clarify more. Thanks!


Sum of two matrices equals product; prove that the matrices commute

Let $A,B$ be square real matrices of the same size such that $A+B=AB$. Show that $AB=BA$.   I have got the result for invertible matrices, but what about non-invertible ones?


How to show that $\mathfrak{sl}_n(\mathbb{R})$ and $\mathfrak{sl}_n(\mathbb{C})$ are simple?

We defined a Lie algebra to be simple, if it has no proper Lie ideals and is not $k$ (the ground field). We have the proposition that $\mathfrak{sl}_n(\mathbb{R})$ and $\mathfrak{sl}_n(\mathbb{C})$ are simple $\mathbb{R}$-Lie algebras, and $\mathfrak{sl}_n(\mathbb{C})$ is also simple as a $\mathbb{C}$-Lie algebra. We have shown the proposition for the case $n=2$ using an $\mathfrak{sl}_2$-triple.  How would I show the statement for general $n \in \mathbb{N}$?  I suspect there's a way to use induction, but don't see how that would work. Also, I have no idea how I would generalize and apply the idea with the $\mathfrak{sl}_2$-triple to higher dimensions. I can't even just do the case $n=3$. How do I generalize?


How do I set up a folder so that anything created in it inherits permissions?

I have a /data folder (actually a partition) for all data that should be accessible by all users (in this case family members). We all have individual user accounts and are often all logged in at any time on this one PC.  How can I set up permissions so that we all retain access to files there no matter who creates them, including new folders? If I create a folder it gets my user and group, so nobody else can write to it.


I want to center h1 next to my img but I can't because of img's padding  it's what I want any soltuion?

Gori News

          header{   width:100%;   max-width: 1800px;   height:99px;   background:#FFF;   margin:0 auto;   background: #FFFFFF;   box-shadow: 0px 4px 5px rgba(0, 0, 0, 0.13);   border-radius: 14px; } header h1{   font-family: Ropa Sans;   font-style: normal;   font-weight: normal;   font-size: 70px;   line-height: 75px;   /* identical to box height */   color: #212121;   text-shadow: 2px 4px 4px rgba(0, 0, 0, 0.25);   display: inline-block; } header img{   margin:12px; }


Use javascript bookmark for specific iframe

I have a javascript debug code that I need to run from time to time on specific website.  The site has several iframes.  When I use Chrome's debug console I can choose which iFrame to run the code.  I created a bookmark with the code javascript:my_debug_code() - but how can I tell it to run on the iFrame I need?  Edit  This is not a duplicate of  as was suggested.  Since I wasn't trying to run the code from the page itself.  My question is different - I want to run the code from a bookmark.  Answer  I can't post a new answer, because question is marked is duplicated.  But taken from @Gothdo answer, apparently all it took for me was to add to my bookmark:  javascript:window.frames[0].my_debug_code()


Can I use ternary operator in following way in C++

(cnt1 == 0) ? { maj1 = arr[i]; cnt1++; } : {maj2 = arr[i]; cnt2++; }  basically it's same as writing (expression) : { statement 1; statement 2 } : { statement 3; statement 4 };  can I use ternary operator in this way actually when I am running this an error is appearing. Can't we use multiple statements for one condition enclosed within {} or () in ternary operator in C++.


$(S^1 \times [0,1])/\sim$ homeomorphic to unit disk $ D^2$

Let $\sim$ be the equivalence relation on $S_1 \times I$ given by $(x,t)\sim(y,s)$ if and only if $xt=ys$ where $I=[0,1]$  How do I prove that $(S_1 \times I)/\sim$ is homeomorphic to the unit disk $D^2$ with the induced topology?


Why is this not a viable key exchange algorithm?

I was just wondering why this kind of algorithm can't be used instead of, say, Diffie-Hellman to exchange keys:  Alice decides on a key she wishes to share with Bob. Alice generates a stream of bytes with the same length as the key (securely, say, with a CSPRNG). Alice sends to Bob: C1 = (key ^ alice_random_bytes)   Bob generates a stream of random bytes in a manner similar to Alice. Bob returns to Alice: C2 = (C1 ^ bob_random_bytes)   Alice XORs C2 with her random byte sequence again, leaving only key ^ bob_random_bytes like so and sends it to Bob: C3 = (C2 ^ alice_random_bytes)    = (C1 ^ bob_random_bytes ^ alice_random_bytes)    = (key ^ alice_random_bytes ^ bob_random_bytes ^ alice_random_bytes)    = (key ^ bob_random_bytes)   Bob XORs C3 with his random bytes and obtains the key: K = (C3 ^ bob_random_bytes)   = (key ^ bob_random_bytes ^ bob_random_bytes)    = key    This seems a lot simpler than Diffie Hellman, so I was wondering: what is the issue with such an algorithm?


As far as I know all photons come from electrons loosing their energy. I remember from physics and chemistry classes, that electron can loose or get only certain determined amount of energy. Also I remember that every nucleous has finite amount of energy  levels.  Since photon is a wave (and I might have read this somewhere) I've always imagined, that photon comes  from electron doing "wobbling" upon stabilizing on a lower orbit and that there is no other way for photon to be born. These statements lead me to conclusion, that there is a finite amount of possible photons wavelengths. Is it so? If not, where am I wrong? Thank you


I would like to evaluate the following integral: $$ \int_{-1}^{1}  \frac{dx}{(e^x+1)(x^2+1)}  $$ I tried various methods but without success.


Maximum value of $\prod_{r=1}^n\cos a_r$ if $0\le a_1,\ldots,a_n\le\frac{\pi}{2}$ and $\prod_{r=1}^n\cot a_r = 1$

What is the maximum value of $\prod^n_{r=1 }\cos a_r$ under the restriction $0\le a_1,a_2,\ldots,a_n \le\frac{\pi}{2}$ and $\prod^n_{r=1}\cot a_r = 1$?   This question I could not actually think of any way on how to solve it because I will not think of any function on which I could apply Jensen's Theorem or any AM -GM inequality. Or any function whose derivative I could equate to zero to get the desired result. Please help , how to solve these type of questions.


How do I convert a triangle mesh to a quads one?

I'm throwing a 3D triangulated mesh into an acoustic simulator.  The simulator instructions say that ideally it wants quads.  If it receives triangles, it will consider them as a degenerate quad (i.e. A B C -> A B C A)  Is there some automatic method of converting most (or all) of my triangles into quads?   Somehow pairing them up...  π


I want to make div (this will be container). In this div I have navbar and another div (this is background img). My container has 100vh. Navbar doesn't have height. Now I want to make "rest of this 100vh" this background div. My main html looks like:  <!doctype html>     <meta charset="utf-8">

Home

About

Contact

                      <button>Add post</button>

     And now my CSS file  *{     margin: 0;     padding: 0;  }  .head-container{     height: 100%;     width: 100%; }  .background {     height: 100vh;     background-color: gray; }    Background div has 969 px height, like my whole window. I want to make 100vh for whole these 2 divs. What am I doing wrong?


Is it possible to give someone your test program without giving away the logic? For example, how can the teachers give their test class that the students could use to compare their results, without actually giving the logic away of the assignment?  Thanks.


What happens when user comes down to low reputation?

I was offering bounty to some good unanswered questions, but I suddenly realized what happens if I come down to below 50 reputation or below 125 reputation points (minimum reputation points required to comment and downvote).  Is it still possible to comment or downvote in that case?


0I'm quite rusty at C++. I've tried various searches but can't come up with an answer. I have the following code:  class Base {   public:     Base() {};     virtual void hello() { std::cout << "I'm the base class" << std::endl; } };  class Alice : public Base {   public:     Alice() {};     virtual void hello() { std::cout << "I'm Alice" << std::endl; } };   class Bob : public Base {   public:     Bob() {};     virtual void hello() { std::cout << "I'm Bob" << std::endl; } };   Base test(int alice) {   if(alice)     return Alice();   else     return Bob(); }   int main() {   Base a = test(0);   Base b = test(1);    a.hello();   b.hello(); }   I would expect the output to be  I'm Alice I'm Bob   but instead it is  I'm the base class I'm the base class   What (aside from Python-on-the-brain) is going on here?


How do I prevent immediate wake up from suspend and/or hibernation?

For a few days, my Ubuntu 12.04 desktop computer has mysteriously been waking up immediately after going to suspend mode.  Since installation, my Ubuntu 12.10 laptop computer has also been resuming immediately after suspend and hibernation.  How to prevent those?


Does this character concept involving never taking a long rest and converting spell slots to sorcery points (aka coffeelock) violate RAW?

Does the following, very cheesy character concept, violate any RAW? Please cite rules or official rulings in your answer. (Apart from RAW, I expect my DM to disallow or limit the concept, in the interest of balance. That is not part of my question.)  Elf. Multiclass: Sorcerer 2+ / Warlock 1+ / Bard 1   Never takes a long rest. Ever. See question,  Specifically, whether adventuring or not, she makes sure that every 8 hour block includes more than 2 hours of combat or strenuous activity, to ensure that no interpretation of long rest rules would allow a long rest to be automatically triggered. Converts warlock spell slots into sorcery points. See . Converts sorcery points into sorcery spell slots (or into spellcasting spell slots, once also multiclassing Bard) via  Spell slots created from sorcery points disappear upon long rest, as per  and a ; therefore these created spell slots will not disappear until used, e.g. for a character taking no long rests Spell slots created from sorcery points are in addition to, and not restoration of the sorcerer's spell slots which refresh on a long rest. This is not 100% clear from RAW or clarifications. But: (a) Flexible Casting uses the phrase, "additional Spell Slots"; (b) the rule stating that created spell slots disappear on long rests is superfluous if created spell slots can only replace expended spell slots -- to have meaning it must be possible to create spell slots which are not replacements; (c) flexible casting does not use the word "recover", which is the word used for wizards'  Restores warlock spell slots on a short rest, and repeats the cycle above, converting warlock spell slots to sorcery points to sorcerer (or spellcasting) spell slots During periods of downtime, takes as many short rests per day as permissible, to build up a stockpile of created sorcerer spell slots Stockpiling requires using bonus actions out of combat,  Stockpiling requires having short rests on downtime days, discussed in a comment below While adventuring, during combat, uses created spell slots to cast spells, and/or uses flexible casting to convert those spell slots back into sorcery points While adventuring, after combat, will use created spell slots with Bard spells to restore hits points, since restoring hit points via long rest is unavailable, and via hit dice is mostly unavailable   I'm pretty sure this is not RAI, but does it violate RAW in some way?


Using Regex To Replace Accross Multiple Lines

I need to change a bunch of HTML elements to just show values instead of showing the input with the value... With normal input's it's a breeze, but with the radio buttons it's proving to be quite a bit more difficult. And I assume checkboxes will have the same issue since they both use multi-line with php loops...  Please Note: $array is an existing array with the field's values in it  Is it possible to use regex to change the below code:
             The Column's Title Is Shown Here	                              <fieldset id="radio_group_name">                     <?php                         foreach ($radio_group as $option){                             ?>                                 <input type="radio" value="<?php echo $option; ?>" name="radio_group_name" <?php echo ($array->radio_group_name==$option ? "checked='checked'" : ""); ?>> <?php echo $option; ?>                             <?php                         }                     ?>                 </fieldset>
   And convert it into:
                 The Column's Title Is Shown Here	                 <?php echo $array->radio_group_name; ?>
   I used  to build a regex command and used  to test it, but RegExr says that there is no match when I use something like /<fieldset id="(?:.*)(?:type\=\"radio\")(?:.*)(?:\<\?php)/gim and other phrases...  When I remove fieldset id=" from the regex it pick's up the input, aswell as when I remove the below line's info it does pickup the fieldset id=" line, but I can't get it to work with the 2 together, think it may be because it's split accross a couple of lines...  Does anybody know of a solution?


In Which Contexts are Plugins Responsible for Data Validation/Sanitization?

I want to make sure all of the data in my plugins/themes is handled securely  before entering the database and before being output to the browser. My problem is that there are situations where the API handles the sanitization for you -- like when saving post meta fields -- and others where the plugin/theme author is wholly responsible for doing it -- like when saving custom settings.  For the scope of this question, I'm not concerned about validating data at the domain level -- e.g., checking that an Age field on a form is between 0 and 120, or that an e-mail address is valid. I'm only concerned about security -- e.g., escaping SQL queries to avoid SQL injection when saving to the database, or sanitizing data that's output to HTML templates to avoid XSS.  For output sanitization, I know that you always need to use functions like esc_html() and esc_attr() when echo'ing variables into HTML templates. But, what about when using ? Do they all sanitize the output already? If so, for which context (general HTML, tag attributes, etc)? Some functions have variants for different contexts (like the_title_attribute(), but most don't.  For input sanitization, I know that I need to use $wpdb->prepare() when making manual queries, but what about when using the Settings API to create a plugin settings page, or saving post meta fields for a custom post type?  Right now I've just been digging through Core and reading tutorials every time I use a function to find out if it sanitizes or not, but that's error-prone and time consuming. I'm hoping to find some kind of comprehensive list of all the possible situations and whether or not the API handles it. e.g.,  API validates/sanitizes   Saving post meta with update_postmeta() Saving user meta with update_user_meta() Outputting a post title - use the contextually appropriate variant of the_title() etc   You have to manually validate/sanitize   Saving plugin options with the Settings API. Pass a callback as the 3rd parameter of register_setting(). Direct database queries: Wrap the query in $wpdb->prepare(). Outputting variables in HTML. Use esc_attr(), esc_html(), etc etc   I'd also be interested to understand why the API provides it in certain situations, but not others. I'm assuming it has something to do with the unknown nature of the data, but would love to hear a thorough explanation.


Generating a list of Source Code Listings of a document

how I can generate a list of source code Listings like a list of Figures ??  here is an exemple of a code source Listings:  \lstset{ numbers=left, stepnumber=1, numbersep=5pt, numberstyle=\small\color{black}, basicstyle=\ttfamily\small, keywordstyle=\color{black}, commentstyle=\color{black}, stringstyle=\color{black}, frame=single, backgroundcolor=\color{lightgray}, caption=Code coté serveur avec Express} \begin{lstlisting}[firstnumber=1, framerule=0pt] % Start your code-block  %Code ...  \end{lstlisting}


Why are 11, 111, 1111, ... equivalent to -1 in two's complement?

According to , the binary numbers 111 and 11111111 are equivalent to -1. Why or how are the binary numbers 11, 111, 1111, 1111 1111, etc. equivalent to -1 in two's complement? Can anyone explain?


How do I set up shared folders in a Windows Virtualbox guest?

I have installed VirtualBox OSE on Ubuntu 11.04 and Windows XP pro as the virtual machine. Now I want to have a shared folder which can be accessed on both, my host Ubuntu machine, and my WinXP guest virtual machine.  How can I do that?


Changing the font color of the command promt window when executing Python script

In C++ I can type system("pause") or system("color A") to change things right inside the executing command prompt window.    Is it also possible with Python? I'd like to color my text of my script that way.


How do you pronounce numbers written in different bases?

The decimal (base 10) number "2" can also be represented as the binary (base 2) number "10".  Let's use binary "10" (equivalent to decimal "2") as an example. I could see a few different ways to go here. Assume that the base doesn't need to be specified, and is understood from the context of the conversation (e.g. two programmers talking about memory addresses would understand that they were using hexadecimal).  It could be "ten", since that is what it looks like. One might even argue that ten, as a concept, refers to a one followed by a zero irrespective of the radix. In other words, ten means "a quantity exactly equal to the base it's represented in".  On the other hand, you could argue that "ten" refers specifically to the quantity; in other words, "1010" in binary, "10" in decimal, and "12" in octal would all be pronounced "ten," and "10" in binary should be pronounced "two".  So how would you pronounce the following numbers?  "10" binary ("2" decimal)  "10" octal ("8" decimal)  "10" hexadecimal ("16" decimal)  "1F" hexadecimal ("31" decimal)


Cannot boot from the Rufus created USB Ubuntu stick

I get error messages in black screen. Timeouts and errors. The error on my Windows XP Dell D830 laptop looks very similar as seen in . The Dell D830 laptop has a dual-core Intel processor with 64-bit support.


Why isn't the Doppler effect (for sound waves) symmetric with respect to source and receiver?

The  formula is $$f = \frac{(v\pm v_r)}{(v\mp v_s)}f_0$$ where $f$ and $f_0$ are the observed and emitted frequency, respectively, and $v, v_r$ and $v_s$ the speed of the waves, receiver and source, respectively (all relative to the medium.) The numerator has $+$ if the receiver moves towards the source, and the denominator has $-$ if the source moves towards the receiver. Now, assume the receiver and the source are approaching each other. My intuition tells me that there should be no physical difference whether it is the source which is moving towards the receiver, or vice versa. Actually, the only difference between these cases shall be the coordinate system chosen. But the equation above suggests otherwise because one velocity is in the denominator and the other one in the numerator. For example, take $v=2$ and receiver and source approaching each other at a speed $u = 1$ (disregarding units.) This, I may say, happens because either $v_s = 0$ and $v_r = 1$ (towards the source), or $v_s = 1$ (towards the receiver) and $v_r = 0$. In the first case, we get $$ f = \frac{2+1}{2} f_0 = 1.5 f_0 $$ In the second case: $$ f' = \frac{2}{2-1} f_0 = 2 f_0 $$ Where does this asymmetry come from? Or why is my intuition wrong?


cp command doesn't overwrite, but creates new folder (second time, third, fourth, .. time it works)

I use the following command to copy a folder (named 'dist') containing a react project to my frontend folder: cd apps/react-app sudo cp -R dist ../server/frontend/client  The first time I run the 'cp'-command, the content of the 'dist'-folder gets copied into the 'client'-folder. I would expect that when I run this command again, the cp-command would overwrite the files in the 'client'-folder. This doesn't happen, instead, the 'cp'-command now creates a 'dist'-folder inside the 'client'-folder en puts all the new files in there. The 3th, 4th, ... time I run the 'cp'-command, it overwrites all the files in the 'dist'-folder, but the files from the first 'cp'-command are still in the 'client'-folder also. How can I cp the files from the 'dist'-folder to the 'client'-folder, and whenever I run this command again, it overwrites (instead of creating a new folder)?


Can a star visually look like a black hole?

Amateur question incoming so please bear with me.  Assumptions  If a black hole is born from a star going supernova, intuitively it should have the same or less mass compared to the star.  Black holes visually appear black because light cannot escape them due to their mass.  Questions   Wouldn't that imply that the light should not be able to escape the original star? Creating a black star that is visually indistinguishable from a black hole? If so, would it also mean that all stars capable of becoming black holes are themselves black stars before going supernova?


How does gravity affect different bodies?

To my understanding,the force of gravity increases as the mass of the body increases (ex. the moon has less gravity than the earth). So, intuitively, I would come to assume that the force of gravity depends on the object's size. Neutrinos commonly pass through the entire earth in very large quantities. It seems gravity has little to no effect on them because their mass is so small. If this is true, why is mass-less light curved/bent into a black hole from its gravity when normally its path is not affected by gravity on earth (and shouldn't be 'cause they have no mass)?


Why does Linux based OS creates . file same directory and .. file in it's sub-directory? How does it work?

Hello there!  Currently, I am studying shell programming and there i just learned symbolic link , hard link, files , directories- related topics. I am trying to understand-     why a directory has two links and when a directory is created - why there are . and .. files in the directory? and how they work?  why . file in a directory is necessary?   Good explanations will be helpful for me.  Thanks  in advance.  Best regards- Nazmul


Suppose I wanted to add two numbers but I can only increment and decrement by 1. I can solve this problem a number of ways including using recursion. When I add m and n I can use the following Python definition:  def slowAdd(m, n):     if n == 0:        return m     else:        return 1 + slowAdd(m, n-1)   This is really confusing to me. Can someone explain how the final return call operates? How does Python interpret the value of a defined function when adding it to 1?


I am trying to make a draft by forcing LaTeX to ignore all images. How do I tell LaTeX to suppress all the image filenames (in the \includegraphics command) and just insert an empty box? The problem with the [draft] options is that it still requires me to have all images in the folder where I have my .tex files.


Some weird glitching of the graphical interface

My Ubuntu is almost unuseable right now. the top and left bars disappeared and the keyboard shortcuts are not working. I am running Ubuntu 14. By opening a folder from the desktop I am able to navigate trough the file system.   The OS showed some problems before I restarted it. I installed Oracle VirtualBox, but it disappeared. Then the Software Center disappeared too.   I can still open applications, but I can't move some of them around the screen.  Is there anything I can do about that, or I shall reinstall the OS?


I have noticed that it is useful to treat $0$ as an even number, and do so. Especially for patterns, puzzles, etc, if I develop a formula that works for something, and uses the parity of the number, then for my formula to work for something, I usually need to treat $0$ as even.     Is $0$ treated as an even number?


How to project a new vector onto PCA space?

After performing principal component analysis (PCA), I want to project a new vector onto PCA space (i.e. find its coordinates in the PCA coordinate system).  I have calculated PCA in R language using prcomp. Now I should be able to multiply my vector by the PCA rotation matrix. Should principal components in this matrix be arranged in rows or columns?


I am hitting a huge wall here. I got this code which checks on database result :  chosenSlotDAO.open();         Log.d("id", chosenSlotDAO.getId());         Log.d("isParked", chosenSlotDAO.getIsParked());         Log.d("parkedRow", chosenSlotDAO.getParkedRow());         Log.d("selectedSlot", chosenSlotDAO.getSelectedSlot());         String idStatus = chosenSlotDAO.getId();         String isParkedStatus = chosenSlotDAO.getIsParked();         String parkedRowStatus = chosenSlotDAO.getParkedRow();         String selectedSlotStatus = chosenSlotDAO.getSelectedSlot();         final String outputA = this.getOutput(this, slotA);          if(idStatus == id && isParkedStatus == isParked && parkedRowStatus != parkedA && selectedSlotStatus != slotA)         {             arriveTView.setText(alreadyParked + chosenSlotDAO.getParkedRow());         }         else if(idStatus == id && isParkedStatus == isNotParked && parkedRowStatus != parkedA && selectedSlotStatus != slotA)         {             Toast.makeText(getApplicationContext(),                  wrongParkingRow,                  Toast.LENGTH_LONG).show();             chosenSlotDAO.updateSlot(id, slotA, parkedA, isParked);         }         else if(idStatus == id && isParkedStatus == isParked && parkedRowStatus == parkedA && selectedSlotStatus == slotA)         {             chosenSlotDAO.updateSlot(id, slotA, setEmpty, isNotParked);              dbUpdateAdd.execute(slotA);             Intent myIntent = new Intent(ParkAArrive.this, ParkLeaving.class);             ParkAArrive.this.startActivity(myIntent);         }         else if(outputA.isEmpty())         {             arriveTView.setText(isFull);         }          else         {             Toast.makeText(getApplicationContext(),                      nowParked,                      Toast.LENGTH_LONG).show();             chosenSlotDAO.updateSlot(id, slotA, parkedA, isParked);             arriveTView.setText(chosenSlotDAO.getSelectedSlot());             dbUpdate.execute(slotA);         }   The class is started by tapping an NFC tag.  LogCat returns :  06-15 04:35:10.818: D/id(12294): 1 06-15 04:35:10.818: D/isParked(12294): 1 06-15 04:35:10.819: D/parkedRow(12294): ParkedA 06-15 04:35:10.819: D/selectedSlot(12294): SlotA 06-15 04:35:10.829: D/link(12294): http://parkit.byethost9.com/db_show_slot.php?slot_name=SlotA 06-15 04:35:11.681: D/line(12294): 14   It clearly shows that user is parked, parkedRow is ParkedA, and SlotA is SlotA. But the if does not work.  But when I start the activity again, nothing except  else if(outputA.isEmpty())         {             arriveTView.setText(isFull);         }          else         {             Toast.makeText(getApplicationContext(),                      nowParked,                      Toast.LENGTH_LONG).show();             chosenSlotDAO.updateSlot(id, slotA, parkedA, isParked);             arriveTView.setText(chosenSlotDAO.getSelectedSlot());             dbUpdate.execute(slotA);         }   works.  Where in the code am I doing wronggg?? Tell me if I left any required info untold..  UPDATE : It seems that I need to change my code so that it can compare String, and yes it's the problem I'm facing.


by 5.30 or until 5.30/ why future tense?

The shops are open only until 5.30. they will be closed by now.   The shops are open only by 5.30. they will be closed by now.  Greetings  Would you kindly tell me the differences that are in the sentences?  I mean the difference between UNTIL 5.30 and by 5.30.  In addition, I wonder the reason why it has been used the tense future, that is  they will be closed by now. !   (I am learning English. would you possibly elaborate your explanations in details readily?)  I think I'll be wait by/until thursday before making a decision.  which one and WHY?    Thank you so much, but my last question:  Are these the acceptable reasons for your previous arguments about that you did not agree with "by 5.30"?, because when we use the following sentence as if the shops are closed twice- for example: once at 3 o'clock and the other one at 7 o'clock or after 5.30  The shops are only open by 5.30. They will be closed by now. ................. As a preposition of time “by” means “on or before”.  She should be here by Sunday.  This means she ought to be here e,g. on Friday or Saturday but definitely not later than Sunday. Use “by” when you refer to a deadline.  “Until” means “up to a particular time but no sooner than that."  The shops are open only until 5.30.  They will not close sooner than 5.30.


How do I give myself access to /var/www to create and edit files and folders in it without 'sudo'?

I have a folder in my web server /var/www.  I need to add files to the folder, but the system will not let me unless I use sudo.  Is it possible to give myself access to modify the folder and its contents, so that I do not need sudo to create files, and so I can use an FTP client to upload files to the web server directly?  The web server is Apache2, in case it matters.


Ubuntu 12.04 and MacBook 4,1 wireless problem; NO wired connection

I just installed Ubuntu 12.04 to dual boot with OS X Lion on my MacBook 4,1 (early 2008). Wireless doesn't work. Ubuntu knows--get the Broadcom driver, right? Sure, but the problem is I'm tethered to an iPhone and thus have no access to a wired connection to download it in Ubuntu! So my question is how do I download the driver on OS X and install it in Ubuntu?  UPDATE 1: I followed the instructions , had problems the first time I tried it (gave me a big screen full of text and had to restart), and now get the text "Invalid ROM contents" before the Ubuntu desktop loads. Wireless still does not work.  Any solutions?  UPDATE 2: I just tried following instructions  and . Didn't work! For some reason it can't get anything from the install media. It seems like certain files are missing or don't work and certain options are just unavailable. With Broadcom's own instructions, I get "Operation not permitted" on the Terminal commands under step 2 of the instructions for a fresh installation.  There has to be an answer!  UPDATE 3: I am able to connect to the internet briefly with Ubuntu using Bluetooth to tether. The connection is intermittent, only staying on for a few seconds before disconnecting and connecting again. I can visit web pages but I can't say it would work on package downloads. I tried installing the Broadcom drivers through "Additional Hardware" but got the same error message I got before about not being able to install it.  UPDATE 4: The output of lspci -nn | grep -i network is  02:00.0 Network controller [0280]: Broadcom Corporation BCM4321 802.11a/b/g/n [14e4:4328] (rev 03)  and of uname -r,  3.8.0-29-generic  sudo modprobe b43 doesn't seem to do anything. I do still have the /lib/firmware/b43 folder and contents as explained in UPDATE 1--it gave me some trouble.


Ubuntu boots on terminal only, how do I recover the GUI desktop?

Where is my Ubuntu desktop? Its booting and going always default to terminal screen, if i press Ctrl+Alt+F7 still in terminal Ctrl+Alt+F1 still in terminal.    No GUI, how do I recover it?  EDIT:  sun@e700gent:/etc/X11$ sudo apt-get install --reinstall ubuntu-desktop [sudo] password for sun:  Reading package lists... Done Building dependency tree        Reading state information... Done The following packages were automatically installed and are no longer required:   libcdio-paranoia1 packagekit-backend-aptcc gdebi-core libxrandr-ltsq2 linux-headers-3.5.0-23-generic linux-headers-3.5.0-23 libcdio-cdda1 libllvm3.1 Use 'apt-get autoremove' to remove them. 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 209 not upgraded. Need to get 0 B/4,016 B of archives. After this operation, 0 B of additional disk space will be used. (Reading database ... 230006 files and directories currently installed.) Preparing to replace ubuntu-desktop 1.267.1 (using .../ubuntu-desktop_1.267.1_amd64.deb) ... Unpacking replacement ubuntu-desktop ... Setting up ubuntu-desktop (1.267.1) ...  sun@e700gent:~$ unity --reset WARNING: no DISPLAY variable set, setting it to :0  (process:2541): GConf-WARNING **: Client failed to connect to the D-BUS daemon: //bin/dbus-launch terminated abnormally with the following error: Autolaunch error: X11 initialization failed.  WARNING: environment is incorrect: No D-BUS daemon running  Did you just try to reset in a tty? unity-panel-service: no process found compiz (core) - Fatal: Couldn't open display :0     sun@e700gent:~$ sudo startx [sudo] password for sun:    X.Org X Server 1.11.3 Release Date: 2011-12-16 X Protocol Version 11, Revision 0 Build Operating System: Linux 2.6.42-37-generic x86_64 Ubuntu Current Operating System: Linux e700gent 3.5.0-36-generic #57~precise1-Ubuntu SMP Thu Jun 20 18:21:09 UTC 2013 x86_64 Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.5.0-36-generic.efi.signed root=UUID=68af0547-17ed-4a85-8369-244d57223f91 ro quiet splash vt.handoff=7 Build Date: 11 April 2013  01:05:39PM xorg-server 2:1.11.4-0ubuntu10.13 (For technical support please see http://www.ubuntu.com/support)  Current version of pixman: 0.24.4     Before reporting problems, check http://wiki.x.org     to make sure that you have the latest version. Markers: (--) probed, (**) from config file, (==) default setting,     (++) from command line, (!!) notice, (II) informational,     (WW) warning, (EE) error, (NI) not implemented, (??) unknown. (==) Log file: "/var/log/Xorg.0.log", Time: Tue Jul 16 17:37:57 2013 (==) Using system config directory "/usr/share/X11/xorg.conf.d"  Fatal server error: no screens found  Please consult the The X.Org Foundation support       at http://wiki.x.org  for help.  Please also check the log file at "/var/log/Xorg.0.log" for additional information.   ddxSigGiveUp: Closing log Server terminated with error (1). Closing log file.   EDIT:  It seems like solving this problem is like rocket science, its unfixed. Instead of wasting time debugging it, i finally re-install the ubuntu.


I'm using booktabs to create table and use cmidrule to span a line across a few columns. The problem is when the cells have background color, the spaces around cmidrule makes it look really bad.   While, booktabs allow you to trim the left and right side of cmidrule, I don't see the options for setting spaces above and below it to 0.   This is the code I have:  \begin{table} \centering \begin{tabular}{lcc}     \bfrule       % this is specialrule with no spaces above and below \rowcolor[gray]{.8} \multirow{2}{*}{}           & \multicolumn{2}{c}{\textbf{Big group}} \\                     %\cline{2-3}                     \cmidrule(){2-3} \rowcolor[gray]{.8}         &  subgroup1 &  subgroup2 \\ \hline Item 1      & 10 & 50\\ Item 2          &  5 & 25 \\ \bfrule \end{tabular} \end{table}   and this is what I got.   Is there any way to fix that?  Thanks,  Update  As David pointed out in his comment, removing spaces won't solve the problem. There's still thin line of white color at the left and/or right of the midline.


What model/year is this bike?  I was wondering because the owner of the bike does not know!  Thank you :D


Linux soft RAID6 how to identify last failing drive

I have a RAID6 array that had been neglected, and just had the third drive fail.  I want to do a ddrescue of the last drive to fail to try to recover the RAID, however I don't know how to identify which drive that was.  To make matters worse, I'm using a 3ware RAID card with JBOD, so trying to identify which drive is mapped to which /dev/sdX device is problematic.  To further make matters more complicated, when I rebooted with the replacement disks, all the device letters changed ...  All three failed disks are visible to the operating system, and partitioned as "Linux raid autodetect".  The filesystem on top was XFS.  Is there any way to query the disk to see when it was last written to?  The failure happened long enough ago that there is no record of it in /var/log/messages*


Jdbc no suitable driver found. Postgresql

So I am trying to establish a connection to my postgresql database in java but I keep getting this error: "java.sql.SQLException: No suitable driver found for jdbc:postgresql://localhost:5432/postgres"  I have seen that there are a lot of people having this issue but none of their solutions helped in my case.  Here is my program:  public class psql{      static String url = "jdbc:postgresql://localhost:5432/postgres";     static Properties props = new Properties();      public static void main(String[] args){         Connection connection = establishConnection();     }       private static Connection establishConnection(){          props.setProperty("user", "userName");         props.setProperty("password", "password");          Connection connection = null;          try {             connection = DriverManager.getConnection(url, props);         } catch (SQLException e){             System.err.println("Didnt establish connection");             e.printStackTrace();         }          return connection;     } }   I have installed the newest postgresql jdbc driver. I have it in the same folder as my java file. I run it in cmd like this:   javac -cp postgresql-42.2.12.jar:. psql.java java -cp postgresql-42.2.12.jar:. psql.java   I have also made sure that the username, password, etc are all spelled right and I simply dont have any idea what else to do. Can anyone tell if I am missing anything?  Edit: There is no need for help anymore. I have found the solution guys. As commented by Mark Rotteveel, I needed to use ; instead of : to sepparate items on the classpath. I cant really mark the comment as an answer so I chose to edit the question. Thank you for the assistance.


I am running 19.10 on a Lenovo flex 11 and all seems to be working smoothly. I regularly check for updates and often get something new installed apparently. Well, today I checked for updates and get the message "Failed to load repository information". My network connection is good...hello, my question is getting in here...so what is going on? Fetching e-mail works, surfing the web works, streaming works, but am unable to download repository information. What's up? results of update attempt:  tom@tom-Lenovo-FLEX-6-11IGM:~$ sudo apt update [sudo] password for tom:  Ign:1 http://dl.google.com/linux/earth/deb stable InRelease Hit:2 http://us.archive.ubuntu.com/ubuntu eoan InRelease                     Hit:3 http://us.archive.ubuntu.com/ubuntu eoan-updates InRelease             Hit:4 http://us.archive.ubuntu.com/ubuntu eoan-backports InRelease Get:5 http://dl.google.com/linux/earth/deb stable Release [933 B] Get:6 http://dl.google.com/linux/earth/deb stable Release.gpg [819 B] Hit:7 http://security.ubuntu.com/ubuntu eoan-security InRelease Ign:6 http://dl.google.com/linux/earth/deb stable Release.gpg Reading package lists... Done W: GPG error: http://dl.google.com/linux/earth/deb stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 78BD65473CB3BD13 E: The repository 'http://dl.google.com/linux/earth/deb stable Release' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. tom@tom-Lenovo-FLEX-6-11IGM:~$   my ignorance is nearly complete, but it appears to me that something may be lacking in the place where updates live - I am grateful for the assistance I get here.


Prove that the Legendre polynomial satisfies $\int_{-1}^1(1-x^2) P_m' P_n' dx=0$

My attempt:   $P_m$ and $P_n$ satisfy the Legendre equation, so   (1)  \begin{equation} \label{1} (1-x^2)P_m''-2xP_m'+m(m+1)P_m=0 \end{equation}   (2)   \begin{equation} (1-x^2)P_n''-2xP_n'+n(n+1)P_n=0 \end{equation}  Multiplying (1) by $P_n'$ and (2) by $P_m'$ and adding and simplifying gives me:  $\frac{d}{dx} [(1-x^2) P_n' P_m']=2xP_n'P_m'+m(m+1)P_mP_n'+n(n+1)P_nP_m'$  I see that integrating from $-1$ to $1$ twice will give me desired LHS, but I can't prove RHS is $0$. Please help!


In a domain name registrar you have the option to set name servers as such: ns1.example.com, etc. and you don't have to specify the IP address of the name servers.   Well, what if I create a set of name servers and have them set as someone else's domain?   What is stopping the domain name from resolving to the lookalike DNS servers I just created ?   example:  Say you have a domain, peanuthead.com. You go to digital ocean and create two name servers with BInd9: ns1.peanuthead.com and ns2.peanuthead.com. you go back to your registrar and set your name servers to ns1.peanuthead.com and ns2.peanuthead.com. this means when you go to peanuthead.com it will query thoes dns servers.   What if someone randomly creates two name servers that you created, ns1.peanuthead.com and ns2.peanuthead.com? what stops the domain peanuthead.com from querying those name servers created by someone else?


In the Harry Potter series, lots of Muggle parents are introduced to the wizarding world because of their magical children. This is seen with Hermione's parents visiting Diagon Alley and various other moments.   In the 1920s USA world that has been created, rules about fraternising with No-Majs are very strict. Is there any evidence in any of the Pottermore articles or recently published film tie-ins which explain what happens with magical children born to No-Majs around this time? (Clearly certain events in the film suggest that they may have no procedure and that there can be side-effects of this - but I feel that those events must be rare!)


I have calculated AIC by using R-studio to compare models. However, I got the following both negative and positive AIC  AIC  8.52  0.41  -7.70  -5.84  -3.84  -2.10  Should I select the negative AIC or positive AIC?  Should I select the absolute value of AIC?  Should I select the lowest AIC although it is the negative value?  Which model should I choose?  I am a bit confuse because normally I get the positive value of AIC.  Thank you.


Prove the roots of $p(z)+z^n\bar{p}(\frac{1}{z})$ lie on the unit circle

I have to prove the following question from "A course in complex analysis and riemann surfaces":     Let $p(z)=\sum_{i=0}^na_iz^u$ be a polynomial with all roots inside the (open )unit disk. Denote by $\bar{p}(z)$ the polynomial $\sum_{i=0}^n\bar{a_i}z^i$. Prove that the roots of $p(z)+z^n\bar{p}(\frac{1}{z})$ lie on the unit circle.   Now it's not hard to see that if $r$ is a root of $p(z)$, then $\frac{1}{\bar{r}}$ is a root of $z^n\bar{p}(\frac{1}{z})$. But that's about as far as I got. I would like a hint on how to prove this.


I am doing a disk to disk copy on a PC and the transfer rate is surprisingly slow. It is a Windows XP machine, which means the operating system is faster than newer generation Windows LOL (the funny part is that I am not even kidding, the XP machine is literally faster than my Windows 10 machine, is it funny or just sad?). I am using Multi Commander to do the transfer. Both of the drives are normal hard drives of sizes of about 500 GB. Many of the files are relatively small, between 50 KB and 500 KB, but some files are megabytes in size. The total number of files is about 1.2 million and the total size of the transfer is 54 GB. According to Multicommander, the average speed is 304 KB/s which seems incredibly slow to me and is taking literally days to transfer the 54 GB required. It seems like the small files are the problem because most of the time the transfer speed is listed as 4 or 8 KB/s which is INSANELY slow. I think the speed just increases exponentially when a larger file is transferred. So, if this is indeed the problem, a 4 KB/s speed on small files, what could be causing this?


normal.mod not found by grub, boot-repair fails to repair

I have a laptop ASUS, model G551J, with ubuntu 14.04.5 installed (64-bit architecture). After running on it a USB live of Lubuntu, 32-bit, the laptop won't boot any more. A grub-rescue prompt turns up with the following error:  error:file '/boot/grub/i386-pc/normal.mod' not found.   I ran a USB live of ubuntu 14.04.5, and executed boot-repair, but it threw an error, with this log:     There is a very similar question with a very good answer here:     But this question is more about why boot-repair failed to repair  this issue.   How can I fix this problem?


Evaluating $\int_{0}^{\pi/4}\ln(1+\tan x)\,dx $

$$\int_{0}^{\pi/4}\ln(1+\tan x)\,dx \\$$   using $$\int_{0}^{a}f(x)\,dx = \int_{0}^{a}f(a-x)\,dx \\$$  I got up to $\int_{0}^{\pi/4}\ln(2)-\ln(1+\tan x)\,dx \\$ but I'm not sure how to integrate this  Thanks in advance


My centos 5.7 is running Magento.  4GB RAM and 4 Cores. Nginx + spwan-fcgi + memcached (Best performance if you ask me).  Now i'm a little bit concerned about the Memory usage.  [root@adikastyle shipment]# free -m              total       used       free     shared    buffers     cached Mem:          3948       3712        236          0        224       **2377** -/+ buffers/cache:       1109       2839 Swap:        10975          0      10975   I've seen in few forum's this command:  # sync; echo 3 > /proc/sys/vm/drop_caches   the website is fast and handle many cur-connections.   but the cache is really strange..   Is this command is safe for production? Does the 2377MB of cache is good ? Do i have to change something?   Thanks.


The question is basically to prove that convergence of $\sum{a_n}$  implies convergence of $\sum {\frac{\sqrt a_n}n}$  with $a_n>0.$  Basically what I tried to show is that:  Since $\sum{a_n}$ converges, then $\lim a_n= 0$ when $n \rightarrow \infty$ , and so $\sqrt a_n \rightarrow 1$ when $n \rightarrow \infty,$ which means it is bounded. On the other hand, $\frac1n \rightarrow 0$ as $n \rightarrow \infty$ and is always decreasing. Per theorem 3.42 in Rudin, that means $\sum{\frac{\sqrt a_n}n}$ also converges.  Is that correct or am I missing something? The solutions on the net appear to differ.


Lightning expression And && behaving wierdly

I was writing some code in aura and came across this scenario which I feel is more like a bug.  and function with more than 2 parameters gives incorrect values.  <aura:application >     <aura:attribute name="first" type="Boolean" default="true"></aura:attribute>     <aura:attribute name="second" type="Boolean" default="true"></aura:attribute>      <aura:attribute name="third" type="Boolean" default="false"></aura:attribute>      Print Answer: {!and(v.first,v.second,v.third)} </aura:application>   And to my surprise output was      Print Answer: true   I tried it in W18 and Spring 18, Still same output. The  for logical expression doesnt provide an answer, I belive the behavior should be consistent. The same formula works fine with database formula fields.


Terminal stopped working [Ubuntu 18.4LTS]

I did a fresh install of Ubuntu 18.4 LTS, coming from Windows, and everything was working great! I installed my needed apps; I'll list them below in case they have something to do with the problem, and the system did an update. I rebooted and now the terminal is refusing to run. If I try and open it, all that happens is that it tries to load but stops after about 5 seconds or so. I've downloaded xterm so that I could use terminal commands again, but this has caused problems with updates & installs as well.    I'd sincerely appreciate any help, I cannot seem to figure out what's wrong and I really don't want to have to reinstall the OS.


submartingale sequence is uniformly integrable

This is an exercise in Karatzas and Shreave's book on stochastic calculus. The $X_n$'s are real random variables on a probability space with $\sigma$ algebra $\mathscr{F}$.  I don't know what my uniformly bounding $L^1$ function should be. I appreciate any help.


I am unable to login again after rebooting my laptop which runs Ubuntu 14.04. I am 100% sure the password I type is correct ( see below - I also ruled out a keyboard issue) so it's not the case that I have forgotten it and would need to reset it.  I have both Unity and KDE but it doesn't work with either of them.  I looked at various suggestions like:   typing my password in the login field to make sure this is not a keyboard issue open a tty. My password still doesn't get recognized at the prompt so I can't go any further. boot to GRUB and open a root terminal but I don't have the root password on my machine so it didn't take me very far. I have also found it very hard to boot into GRUB as holding SHIFT while booting has worked a few times only and I can't get it to work anymore.   Also, not sure this is relevant but from the unity/kde login screen I am unable to connect to wireless (I get a permission error)  What should I try next?


Use the same number for the same theorem

I state a theorem first, and want to write the proof in the later section. And I want to restate the theorem when I am going to prove it. So in the whole paper, I write the theorem for two times, but I want them have the same number. How can i do this?


Uncommon behaviour of IS operator in python

From some of the answers on Stackoverflow, I came to know that from -5 to 256 same memory location is referenced thus we get true for:  >>> a = 256 >>> a is 256 True   Now comes the twist (see this line before marking duplicate):  >>> a = 257 >>> a is 257  False    This is completely understood, but now if I do:  >>> a = 257; a is 257 True >>> a = 12345; a is 12345 True   Why?


My client would like to have his eCommerce (custom-made) site secured from DDoS attacks. What strategies can I implement? There are multiple forms in the purchasing flow --- searching, drilling-down to the product, user information and payment and I want to avoid captchas.


What are the best hosting for big websites/forums?

I bought a Deluxe hosting plan at Godaddy years ago to host my websites. Recently I decided to move one of the websites to a new host, so I have bought a new Deluxe plan for that website (which is a big forum). But since the migration, the website has been much slower than before, and I have received warnings that the resources for my account have been limited.   I realised that on these new Deluxe plans (which they call "with cPanel"), the CPU and Memory (and other) resources are limited (1 CPU core and 512 MB of memory), things never happened with the old Deluxe plans (which they call "Web classic"). (I have never had any resource problems with the other older account, even though I have used it for hosting many websites).   I'm considering cancel the order and move the website to yet another host.  Could you suggest me a hosting service (that you are using or have already used) with good amount of CPU & Memory resources at a reasonable/comparable price?   Thank you in advance for any suggestions!


"Fudging" dice rolls - how important is it?

Similar to the Fate Fudge dice, sometimes a DM might "Fudge" a dice roll (without using the actual Fudge dice). I.e., they might make a roll pass/fail, regardless of what is on the actual dice.  For example, if a PC is low on health, and the DM rolls a critical hit on that PC they might "Fudge" it to lower it from a critical hit so the player might not die outright.  In what situations should a GM "Fudge" a dice roll, and how should it be handled?


This question is prompted by reading  to a question about using the Polearm Master feat's bonus action after a Shove and halberd Attack  In the section "Making an Attack" (PHB, page 194):     If there’s ever any question whether something you’re doing counts as an attack, the rule is simple: if you’re making an attack roll, you’re making an attack.   Shoving does not require an attack role but rather a contested Athletics check.  Under "Shoving a Creature" (PHB, 195)     Using the Attack action, you can make a special melee attack to shove a creature, either to knock it prone or push it away from you. [...] You make a Strength (Athletics) check contested by the target’s Strength (Athletics) or Dexterity (Acrobatics)check (the target chooses the ability to use).   The text specifically says Shove is a "special melee attack" Is this a case of "specific beats general" where the specific wording of Shove makes it an attack even though the general definition of an attack is different? Alternatively is the wording of shove just using common language or is it intended to mean something different?


Does "medium appearance residential buildings" express that the buildings are somewhat aged and worn out?

Is "medium appearance residential buildings" correct? Am I not sure it's correct or not?  Is it the representative of "aged and worn out residential buildings"? How else might I express this? I want a phrase that combines semi-aged and semi-worn out in one.   I am writing a scientific paper. I categorized buildings by their qualitative state in three classes. I simply want a good name for those classes. those classes were good appearance buildings, medium appearance buildings, and decayed buildings. (In the case of repair, quality of material and how rusty they are - just physical appearance.) But I think this combination is not good for repeated usage in my text.


Is it possible to use simple markup (particularly italics) in tag wiki excerpts?

For the purposes of titles, in particular on sites like Sci-Fi & Fantasy, Literature, and Movies & TV, is it possible to allow basic markdown appropriate for titles (italics) in the tag wiki excerpts?  I was recently editing a tag wiki on Movies & TV and realized that the markdown does not work in the excerpts so I'm forced to either leave titles without appropriate text decoration (which is what is generally done on both sites) or to use quotes. Neither of these solutions are "correct".     Is it possible to allow italics specifically on sites that warrant it by having a large volume of book, film, or TV show titles as tags? Or is this something not possible due to how the excerpts work?  This is a very specific request to be only used in very special cases and most likely would not be enabled on all Stack Exchage sites. I understand that, in general, markdown is not popular for tag wiki excerpts but I think that it may be worth making an exception if it is beneficial for clarity.


How to take the output of a BAT file and save it to a string

I have a BAT file that I am running using the following code:  @ECHO ON java com.mypackage.test send   which result in this:  C:\myfolder>java com.mypackage.test send EXEC Sending... Received 1 response(s) Status Code: C00   How do I take the Status Code value (C00) and save it to a string in my WinForm C# application so I can use it for other actions?  I set the..  proc.StartInfo.RedirectStandardError = false; proc.StartInfo.RedirectStandardOutput = true;  but not sure what to do next...


Blender 2.8 Leaf Transparency Issue, with Eevee

Somehow i'm not being able to pull this off.    I've tried searching on google for solutions but couldn't find it.   I thought the setup was quite simple, but it don't seem to work properly.  If you take a look at the image below you'll see what i mean.  I've tried changing the Blend Mode on the Settings TAB, i've enabled screen space refraction...        It seems that i'm missing out on something.     Any thoughts ?   Thank you


What is the distance a creature or player can travel if they have multiple types of movement speeds?

What is the distance a creature or player can travel if they have multiple types of movement?  For example, the  has a 40 ft walking speed, a 40 ft climbing speed, and an 80 ft flying speed. Can it move a total of 160 ft in a round using each of those fully, or is there another way this is calculated?


I always thought that the opposite of postpone is prepone(also remember my english teacher telling me this). Today I realised that the word prepone does not exist in the dictionary. So is it used informally or does it exist?


Should I add references to conference presentations?

I am preparing a CS conference presentation and wondering how can I handle the references. I am thinking about three different possibilities:   Ignore them! Just list them at the end of the presentation List them and cite them within the presentation.    I chose the first option since anyone interested can go and check the whole set of references in the actual paper.    Does this mean not crediting the others for their work? How this is usually handled in CS conferences?


Does brewing tea for longer result in higher caffeine content?

The ISO standard for brewing tea says "6 minutes".  Of course different teas have vastly different properties, but...  For "average commodity black tea" and "average commodity green tea", will leaving the tea bag in longer (say 1 hour or 1 day) result in higher caffeine content in the cup?  How much?


I have  a question  about $F$- algebras, please help me:     If $A$ is  a nonzero finite dimensional unital algebra over a field   $F$ with $char(F) = 0$, and let $\varphi$  be an automorphism of $A$,   how can we prove that $\varphi(a)  \neq a +1$  for every $a \in A$?


Joining a list in python with different conditions and separator

I have a list of integer  a=[1,2,3,4,5,6,7,8,9]  and i must create a string with the integers separated by spaces and every five number i must add a '\n'  string='1 2 3 4 5\n6 7 8 9\n\n'    I have tried with a join like that:  string=' '.join(a)  but i don't know how to add '\n' with a condition.


How does this logic work: k+=(x=5,y=x+2,z=x+y) ;

How does this logic work: k+=(x=5,y=x+2,z=x+y);  How it will give result k == 22. When I initialize the value of k = 10  #include <stdio.h> int main() {     int x,y,z,k=10;     k+=(x=5,y=x+2,z=x+y);     printf("value of k %d ",k); //why it will show value of k =22     return 0; }


How to mount a NTFS partition in /etc/fstab?

I have two partitions that I want to mount on startup: /dev/sda3   /mnt/devel  ext4    defaults    0   2 /dev/sda2   /mnt/excess ntfs    defaults    0   2  The ext4 partition mounts fine (owned by me, writable only by me), but the NTFS mounts owned by root with R\W permission for all. How to fix this? drwxr-xr-x  7 amanda amanda 4096 2012-03-14 19:07 devel drwxrwxrwx  1 root   root   4096 2012-03-14 22:38 excess


Create a center line between 2 polyline - QGIS

I want to create a center line for a river (polygon). I thought about simply creating a new line manually, but it would be a long and imperfect process. If there is a way to automate this process, that would be much better.   Can anyone help?


How do I add a class in table with jquery

I'm making a simple calendar using javascript for my task. I tried to add a class on the day that the column will be selected. But i got problem with that if i did on this day that code successfully, but if i did on next/prev month it's not working. How do I resolve this?  here's my code :    <button class="btn btn-default prev"></button> <button class="btn btn-default next"></button>

      *Sorry my english is not very good :)


Regex Getting around parentheses in a element

I have a question with regex, I'm trying to scrape a stock price. The element surrounding it looks like this:  17.89   As you see there are multiple parentheses in that element so when I try to narrow it down with the following code the parentheses cause my script not to display any results.  MatchCollection list = Regex.Matches(data, "<span class=\"Trsdu(0.3s) Fw(b) Fz(36px) Mb(-4px) D(ib)\" (.+?)", RegexOptions.Singleline);   I Know you can ignore quotation marks using \ but is there away to ignore parentheses?


Space is expanding but the space around me isn't

Everyone says space is expanding and distances between galaxies growing. But space isn't limited to outside of the earth. Space is everywhere on earth and around me. However I don't notice any expansion of the space around me? Is it because I am on Earth and the local space is affected by gravity?


PDO prepare causes SQLSTATE[42000]: Syntax error or access violation: 1064

this is already asked million times already, but I got this error while creating a database in php using pdo. Below is the part that causes this error.  try {     $conn = new PDO("mysql:host=$servername", $username, $password);     $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);      // create database      $db_query = $conn->prepare("CREATE DATABASE IF NOT EXISTS ?");     $db_query->execute([$myDB]); } catch(PDOException $e) {     echo  "<br>" . $e->getMessage(); }   I could create the database just fine without using prepare, so I wonder if prepare cannot be used to create database by design.


Use induction to prove that when $n≥1$, $a_i\in R$, $a_i > 0$, if $a_1a_2...a_n=1$, then $(1+a_1)(1+a_2)...(1+a_n)≥2^n$

Use induction to prove that when $n≥1$, $a_i\in R$, $a_i > 0$, if $a_1a_2\cdots a_n=1$, then $(1+a_1)(1+a_2)\cdots(1+a_n)≥2^n$.*  The base case is simple, but I do not know how to complete the inductive step:  If $a_1a_2\cdots a_{n+1}=1$, then $(1+a_1)(1+a_2)\cdots(1+a_{n+1})≥2^{n+1}$.  I made a case when $a_{n+1}=1$, but could not complete the other cases.  There are other proofs of this inequality, but I do not think they use the "if" part require in this proof.  *Another way to write this inequality is as follows: $$ \left(\frac{1+a_1}{2}\right)\cdots \left(\frac{1+a_n}{2}\right) \ge 1 .$$


RSA vs El Gamal digital signature. Which is more secure?

I'm reading about the  concerning digital signatures and I can't understand whether RSA is more secure than El Gamal digital signature. Well, they are both prone to forgery, but I don't see which signature is better in terms of security.


large integers change their value after applying operation

Below is the small segment of code from my script:  The logic added is to covert any data value as per the scale value   x = "11400000206633458812"     scale = 2     x = x.to_f/10**scale.to_i     x = x == x.to_i ? x.to_i : x     puts x   observe that the value comes out to be "114000002066334592"  which is different from the initial value of x.  My test-points are failing at this point.  x can be any value. If i use x = 156, the output is correct, but when the length of the integer exceeds 16 digits then the problem arises.  The expected output in above case is 114000002066334588  Can anybody help me why the value is changing and how to fix it?


The relation between Internal Pressure and flow rate in a balloon

I'm working on a project. We have two balloons, connected by a hose with a valve.We know when we open the valve, by according to internal pressure of each balloon, air goes form the higher pressure balloon to lower pressure  balloon. I want to know the relation between internal pressure of the balloons and the flow rate between these two balloons. Pay attention, I don't want the air transfer direction, I want the FLOW RATE.  Thanks.


In Pokemon Go when I try to fight a gym it starts the first battle and then exits from the battle, back to the gym screen.  Why is this happening?


How can I formally classify a function that increases to infinity?  Intuitively I know (I don't why I know it, maybe from school) that functions like:  $$f(n) = n^2 + n + 123 + log_2n$$ $$f(n) = n^2 + n$$ $$f(n) = 12 * n^2$$  Have quadratic class  Functions like:  $$f(n) = log_2n + 2$$ $$f(n) = 5 + log_5n + 2$$  Have logarithmic class  I did this classification because it is obvious for me that $n^2$ has higher growth rate than $n$ and $n$ has higher growth rate than $log_2n$  But do we have any common and formal way to classify a function?   Or more commonly speaking, what does exactly word class means when we talk about functions?    UPDATE:  Someone suggested me that I should look at Big O notation. I don't see how it can solve my problem.  Let's say we have a function like: $$f(n) = 2^{(n + log_2n +12)} + 3^{(5n + log_2n)}$$  How Big O can help me to determine at what set (class) of functions $f(n)$ belongs to?  Moreover, we can use Big O notation only after function is been classified, not before. So I need some math framework to classify function and only then I can use Big O notation.


Analytic functions with nonessential singularity at infinity must be a polynomial

This is an exercise from Alhfors Complex Analysis book- to show that an analytic function with a nonessential singularity at infinity must be a polynomial. It seems like it should probably be pretty straight forward, but I must be missing something. If it has a removable singularity at infinity than it extends to an analytic function on the Riemann sphere, and so must be constant by Liouville's theorem. What if there is a pole at infinity though? This was homework some time ago, and  I never finished it :/ but have been thinking about it again recently. Thanks :)


My SEO team told me Google SEO engine uses the page speed in its algo to rank the pages. It is confirmed by this  too.  In my case, page speed is different for end-user coming from browser than google bot crawling the site. My question is does SEO uses the page speed experienced.  by end user  or by google crwaler bot ?  Also From the blog I mentioned,  looks like it just uses the Time to first byte(TTFB) not the time taken to render/paint the dom on the browser?


I can't type § in minecraft for some reason

So I try typing Alt+Numpad1Numpad2 (that's §) and  nothing happens and it wont copy and paste it ether I'm trying to name a shulker box §2FOOD so it says FOOD in dark green, it already says 'Shulker Box' in dark gray and in the anvil it says '§7 Shulker Box' but when I try to replace the 7 with a 2 it just removes the § in fact when I try to change the name at all it automaticaly gets rid of the § but what i think the weirdest part is that I can add any other symbol such as ☺ ☻ ∞ and ╚ for example please help me because I cant find anything else to do


Why is the camera tilting around the z axis when I only specified x and y?

My goal is to program a camera to point towards the mouse cursor. I attached the following script to the Main Camera.   using UnityEngine; using System.Collections;  public class CameraController : MonoBehaviour {      public float sensitivity;      // Update is called once per frame     void Update () {         transform.Rotate (Input.GetAxis ("Mouse Y") * -1 * sensitivity, Input.GetAxis ("Mouse X") * sensitivity, 0);     } }   I "told" the camera to rotate around the x and y axes. Whenever it does this, the camera tilts sideways. When I checked the rotation of Main Camera, I saw that the z rotation had changed. Why is it rotating around the z axis when I left it at 0?


Disabling module with config sync and removing with composer

I have an issue disabling modules, I've searched but cannot find something useful:  - Developer A disable module and via composer remove it  - I pull his changes so i run composer install that remove the code, then drush cim to update configuration, but it complains that the module is missing while it's trying to delete its configurations.  What's the right way to do this? I can't import config before running composer install because along the uninstalled module there could be also new modules needed for the configuration import.


I stumbled upon this code and don't understand the ^ operator in the string ^name declaration. I found on google that it is a bitwise XOR operator but can't see the relevance here:     ref class Animal{      int legs;      String ^name;      };


Natural (human alpha-numeric) sort in Microsoft SQL 2005

We have a large database on which we have DB side pagination. This is quick, returning a page of 50 rows from millions of records in a small fraction of a second.  Users can define their own sort, basically choosing what column to sort by.  Columns are dynamic - some have numeric values, some dates and some text.  While most sort as expected text sorts in a dumb way. Well, I say dumb, it makes sense to computers, but frustrates users.  For instance, sorting by a string record id gives something like:  rec1 rec10 rec14 rec2 rec20 rec3 rec4   ...and so on.  I want this to take account of the number, so:  rec1 rec2 rec3 rec4 rec10 rec14 rec20   I can't control the input (otherwise I'd just format in leading 000s) and I can't rely on a single format - some are things like "{alpha code}-{dept code}-{rec id}".  I know a few ways to do this in C#, but can't pull down all the records to sort them, as that would be to slow.  Does anyone know a way to quickly apply a natural sort in Sql server?    We're using:  ROW_NUMBER() over (order by {field name} asc)   And then we're paging by that.  We can add triggers, although we wouldn't. All their input is parametrised and the like, but I can't change the format - if they put in "rec2" and "rec10" they expect them to be returned just like that, and in natural order.    We have valid user input that follows different formats for different clients.  One might go rec1, rec2, rec3, ... rec100, rec101  While another might go: grp1rec1, grp1rec2, ... grp20rec300, grp20rec301  When I say we can't control the input I mean that we can't force users to change these standards - they have a value like grp1rec1 and I can't reformat it as grp01rec001, as that would be changing something used for lookups and linking to external systems.  These formats vary a lot, but are often mixtures of letters and numbers.  Sorting these in C# is easy - just break it up into { "grp", 20, "rec", 301 } and then compare sequence values in turn.  However there may be millions of records and the data is paged, I need the sort to be done on the SQL server.  SQL server sorts by value, not comparison - in C# I can split the values out to compare, but in SQL I need some logic that (very quickly) gets a single value that consistently sorts.  @moebius - your answer might work, but it does feel like an ugly compromise to add a sort-key for all these text values.


nginx: redirecting to SSL based on the original request URL (not $server_name)

I have an nginx config that is similar to this:  server {   server_name my-english-site.com my-french-site.com;    listen 0.0.0.0:80;    rewrite ^ https://$server_name$request_uri? permanent; }  server {   listen 0.0.0.0:443 ssl;   server_name my-english-site.com my-french-site.com; }   When someone goes to , it redirects to , because the rewrite directive uses the first server in the $server_name directive.  I tried replacing $server_name with $host, expecting it to use the value of the Host request header. But it still redirects to the English URL.  How can I get non-HTTPS requests redirected to the corresponding HTTPS URLs?  Thank you!


Emacs text-scale-adjust causes line numbers column to incrementally shrink and disappear

I've set up emacs to display line numbers (global-linum-mode 1), and it works until I start enlarging the text via text-scale-adjust    The line numbers column starts to shrink, and disappears entirely after a few increments. When it has fully disappeared, further increments have no more effect on the left edge.    Is this a know issue? Is there a workaround?    Using GNU Emacs 23.1.1 in Ubuntu 10.04.


The Matching Problem/Derangements - n letters to n people

There are n letters addressed to n eople at different addresses. The n addresses are typed on n envelopes.  A disgruntled secretary shuffles the letters and puts them in the envelopes in random order, one letter per envelope.  Find the probability that at least one letter is put in a correctly addressed envelope. [Hint: use the inclusion-exclusion formula.] What is the probability approximately, for large n ?    My attempt at a solution:  P(all correct) = $\frac{1}{n!}$  P(n-1 correct) = ${n \choose n-1} \frac{1}{n!} = \frac{1}{1!(n-1)!}$  ${n \choose n-1}$ ways of selecting n-1 correct letters.  P(n-2 correct) = ${n \choose n-2} \frac{1}{n!} = \frac{1}{2!(n-2)!}$  ...  P(n-n correct) = ${n \choose n-n} \frac{1}{n!} = \frac{1}{n!(n-n)!} = \frac{1}{n!}$  This all looks ok to me, but I tested this for a case of 4 people, (I think the theoretical value should be $\frac{9}{24}$ but obviously that is not what I got. Can someone correct my logic please? Also, with regards to the hint about inclusion/exclusion - where would that come in?  I read about derangements on Wikipedia but it did not make total sense to me (the derivation).  I would appreciate any advice whatsoever including references to other material.


No-slip boundary condition for viscous fluids

When dealing with fluid mechanics of viscous fluids, both theoretically and numerically, I've always been told that the boundary condition applied at solid walls has to be a no-slip one. My teachers or textbooks never really explained why, except sometimes "well, the fluid's viscous, so it sticks to solid" which is far from an explanation to me. Therefore I'm reading a little bit to understand the real origin of this condition, and so far there is on thing that I don't understand in what I've found: in Volume II of Modern Developments in Fluid Dynamics by S. Goldstein, it is written that:     "[...]; finally he [Navier] decided on the first [hypothesis on the behaviour of a fluid near a solid body], on the grounds that the existence of slip would imply that the friction between solid and fluid was of a different nature from, and infinitely less than, the friction between two layers of fluid, and also that the agreement with observation of results obtained on the assumption of no slip was highly satisfactory."   I do not understand what is in bold: what does the "different nature" of friction means, and why would it be "infinitely less"?  NB: After this statement, Goldstein refers to a bibliographic entry, but I don't know if it's possible to find such archive on the Internet. Here it is anyway: Trans. Camb. Phil. Soc. 8 (1845), 299, 300; Math and Phys. Papers, 3, 14, 15.


Cut a part of multiple lines text in Java regular expressions

I have the following text:  (Some text before...) display_name = lo name = lo is_up = 1 index = 1 is_virtual = 0 is_point_to_point = 0 MTU = 65536 hardware_address = (null) parent = (null) ip_counter = 2 inet6 addr = /::1 inet addr = /127.0.0.1 ---------------End_of_text--------------------- (Some text after...)   I'm trying to get this all part between "display_name = lo" and "---------------End_of_text---------------------", when "display_name = lo" and "End_of_text" are not include.  I tried to run the following:  String pattern = "^\\sdisplay_name = lo\\s+(.*)---------------End_of_text---------------------";          Pattern r = Pattern.compile(pattern, Pattern.DOTALL);          Matcher m = r.matcher(interfaceData);          if (m.find()){             System.out.println("Group 0 found value: " + m.group(0) );             System.out.println("Group 1 found value: " + m.group(1) );             System.out.println("Group 2 found value: " + m.group(2) );         }         else {System.out.println("NO MATCH");}   There is no match, what am I missing?


Why does the black hole's matter ring in the image released on April 10th seem to lack blue/red shift?

If the matter around a black hole is spinning around it at nearly the speed of light, then the blue/red shift on each side should be quite visible (even though we're watching at an angle). But in this image I fail to notice any.


My situation like the following:   Web server hosted in Google Cloud with domain name lets say: example.com Mail server hosted in Linode (lets say in server name: server.myserver.com) using cPanel with Mail Only and use example.com domain name.   The goal is to separate web and mail server in different server.  In Google DNS :   I set A record for example.com to Google cloud IP I set the MX record to mail.example.com I set A record for mail.example.com to Linode IP I set SPF and DKIM with TXT record that generated from cPanel (linode side) I set PTR to server.myserver.com         PTR status is passed when I check from    SPF status passed from    DKIM status passed from       With all settings above I can get incoming email with no issue, but when try to send an email, all email trapped in SPAM folder.  What's wrong with the settings above? Please help and thanks before :)  UPDATE     After checking email header and get spf and DKIM are pass (OK) but   still trapped in spam, so I end it up by using third party of email   service. In this case I use Amazon Simple Email Service. Thanks all   for your help, really appreciate it.


I want to replace the JSON in my HTML with a URL endpoint () that has the same JSON data. Any idea how I could go about doing that? Preferable without using jQuery.

ACADEMIC


Half of speed for 1Gbit/1Gibt network on RotuerOS mikrotik

I have Mikrotik router which is configured with basic guides. I reset router when I got it from a friend and configured from scratch. Problem is speed is maximum 500Mbit/500Mbit instead of 1Gbit/1Gbit.   I did some tests. Here are results with following configurations:  ISP <-> ISP Router (bridge port) <-> Laptop 850/900Mbit ISP <-> ISP Router (bridge port) <-> Mikrotik <-> Laptop Around 500/500Mbit ISP <-> ISP Router (bridge port) <-> Mikrotik <-> switch <-> Laptop Around 500/500Mbit    I also tried downloading From 2 computers at same time. Max WAN transfer is around 500/500Mbit  My router model is RB750Gr3 with RouterOS v6.43.7  When testing speed between 2 computers connected to same group of bridged interfaces speeds are close to 900/900Mbit between two computers. So basically bottleneck is between Mikrotik WAN port.  While testing speedtest there is around 30% CPU usage.  My main goal is to know what is a bottleneck of this router.  Accordnig to charts it should be capable of 1Gbit+ speeds with 1500 MTU    My NAT table is as follows:  0    chain=srcnat action=masquerade out-interface=internet1 out-interface-list=WAN log=no log-prefix=""  1    chain=dstnat action=dst-nat to-addresses=192.168.5.5 protocol=tcp dst-address=111.111.111.111 in-interface=internet1 dst-port=80 log=no log-prefix=""  2    chain=dstnat action=dst-nat to-addresses=192.168.5.5 protocol=tcp dst-address=111.111.111.111 dst-port=443  3    chain=dstnat action=dst-nat to-addresses=192.168.5.5 protocol=tcp dst-address=111.111.111.111 dst-port=8000-8999  4    chain=dstnat action=dst-nat to-addresses=192.168.5.5 protocol=tcp dst-address=111.111.111.111 dst-port=32400 log=yes log-prefix=""  5    chain=dstnat action=dst-nat to-addresses=192.168.5.5 protocol=udp dst-address=111.111.111.111 dst-port=32400 log=no log-prefix=""


I can't play pokemons on 4G, but only on wifi. It worked since yesterday when I couldn't play it anymore. I have htc desire. Please, anyone?


XNA's SpriteBatch resizing is not sharp as i use it

I draw a TiledMap with TiledSharp and i've introduced a resize factor when drawing, that looks like this:  SpriteBatch.Draw(TileSet                                                   // The input Texture2D                  , new Rectangle((int)x                                    // The tile rectangle                                  , (int)y                                  , tileWidth * ScaleFactor                                  , tileHeight * ScaleFactor)                  , tilesetRec                                              // The tile offset on tileset texture                  , Color.White);                                           // just white      (note: it's not formated on different lines in my code, it's just i'm making it such way that anyone can understand without having previous lines)   but when i start the game it end up really blured and has some Strange outline   Can someone help me getting really sharp tiles instead of this?  N.B: i Don't want to resize the tileset file, it's to complicated for later modifications regarding the 16x16 style i want for my game. also i'm using Tiled to generate the Tiled Map but i Don't think this last info is relevent.


I am preparing for the F=ma Physics Test and I was wondering if anyone could recommend a book on Newtonian Mechanics at a college level textbook based on algebra.


Fill a formula down without dragging in Excel for Mac 2011

Does anybody know the keyboard shortcuts or menu commands to fill a formula down without dragging? I'm using Excel for Mac 2011 on a MacBook.  I've got a spreadsheet like this pattern but for like 5000 rows:  A, B, C, D 5, 1, 3   =SUM(A1:C1) 3, 2, 4 ...   I know how to hover over D1 and get the handle and drag down, but there must be an easier way.  There are a billion tips online but I'm not finding any that work.  FWIW, Macbook has some exceptions to shortcut key rules, so that's probably why, I guess.  But anyhow, anyone know how to do this?  PS: I would have thought "fill series" would be a choice but no. Here's a picture.


I installed synaptic package manager to manage my packages and, I see many kernels, that are not being used, can I delete them? There are 2 - 3 using kernels and many non using.


2 Tricks to prove Every group with an identity and x*x = identity is Abelian - Fraleigh p. 48 4.32

I didn't see the similar question. My question isn't a duplicate because I understand how to prove this. But I don't understand where the hint comes from. That question doesn't flesh it out.    Pretend the question didn't give the hint. How can you prognosticate (please see my profile) to Consider $(a*b)*(a*b)$? This trick is too magical and superhuman. I didn't see it. The other trick is to write $e *e = (a*a)*(b*b)$. How can you prognosticate this?


Why does LaTeX replace some spaces with brackets or underscores in the listings environment?

I'm using LaTeX on Windows with MikTeX and I'm seeing some odd behaviour. In the output, some of the spaces are replaced with bracket-like underscores. This is the code:  \documentclass[10pt]{article} \usepackage{listings} \begin{document} \begin{lstlisting}[language=SAS, title=SAS code to format data on government patients] code code;                                          code code;  code; code; code; c       identity = "Subject's identity"       variable = "Subject's name in government archive of files"; FORMAT gender genderft.        code        response responseft.; RUN; \end{lstlisting} \end{document}   This generates the following output:    I've replaced all tabs with spaces, copied the code into a plain text editor and retyped all the spaces, and still the problem persists. Even copying the code into the editor from my browser after the question is posted doesn't work. The bracket/underscores are still there.   No other code snippets in my document present this problem, yet they also use identical listings syntax to this example and also use SAS code.


plaintext and its encrypted version known

I have a (long) text in two versions, encrypted and plaintext. I think it was encrypted using a substitution cipher method (I'm pretty sure, indeed).  I'm not good in this matter, I know little about it, but I would know if there's a way to know the function/secret used for encrypt that text.  I'm ready to study, anyway :)


Issues with France visas website to fill out online application of Schengen visa

I will be attending an academic conference in France and have been advised by the people who already have been to one of the Schengen member countries to mention the purpose of my visit as "Other" and write academic conference or colloquium.  The problem is that since December, France is taking applications from the site "French-visas" where we have to fill in an interactive online form and a PDF is generated from it. In the purpose of visit section, there is no option to mark "other" from the drop-down menu but it is showing as an available option in the generated PDF. I have tried other browsers as well, to see if there is any browser compatibility issue, but it didn't help. Any suggestions to tackle the problem?


Why do paintbrush loops get thicker at the top in Illustrator?

When I do swirls in Illustrator with the paintbrush tool I often get this result (see image).    The loops doesn't get perfectly rounded, instead sometimes some of them gets thicker at the top of the loop... It tends to happen more if I paint small with low brush sizes. Why is this happening?


What files should I prepare to make commutative diagrams in TeX Writer?

I am using an iPad app TeX Writer and would like to draw a commutative diagram. I can use amscd in the app but it is not sufficient for the diagrams I want to draw.  To include new package, I need to prepare a folder texmf-local in which I create a folder TeXinput and Zip it. TeXinput is a flat directory, no sub directories allowed. It holds everything except for font files. ()  I tried to add xy package but it did not work for me. I'm not sure if I prepared right.  Could you tell me how to prepare the flat directory file so that I can add some diagram packages? Like, which files I should include in the folder TeXinput.  It is ok if the package is not xy but any other package is acceptable if I can draw commutative diagrams with diagonal lines etc.


$f(x)=x^n−nx$ where $x \ge 0x \ge 0$ and $n \ge 2n \ge 2$.    Determine the coloured area on the graph when $n = 2$, greater than 2 and when it goes towards infinity.  When I put $n=2$, the area should therefore be $−1,057$  When I put it for instance $n=10$ I get answer $−5.85$  are my calculations correct?  Also, what happens when $n$ goes towards infinity, how can we make a mathematical conclusion, and how can I prove it?


Is there a closed form expression for the sum of the reciprocal values of the first n natural numbers?

Does there exist a closed form expression for this sum?  $$ \sum\limits_{i=1}^n \frac {1}{i} $$


Let $H$ and $K$ be normal subgroups of $G$ such that $H \cap K = \langle e \rangle$ and $HK = G$. Prove that $G$ is isomorphic to $H \times K$.

I can't figure out how to do this. Can anyone give me some hints?


I am wondering what is the probability density function for the normal cdf $\Phi (aX+b)$, where $\phi$ is the usual standard normal cumulative distribution function  I want to calculate $\mathbb{E}[\Phi(aX+b)]$ but i am stuck on how to get the distribution. thank you =]  note: X is normally distributed


PHP SQL Adding several people to the project

I need help creating a project system to which I can add a few people. What database structure should I create to assign several people to the project?  My database  users  id   name  surname  project  id   name  desc  owner  member


I have a shapefile with following projection information:  PROJCS["kl2",GEOGCS["kl3",DATUM["D_Everest_1830",SPHEROID["Everest_1830",6377299.36,300.8017]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Polyconic"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",76.5],PARAMETER["Latitude_Of_Origin",8.5],UNIT["Meter",1.0]]  How can I convert this datum to WGS 1984?


How to move fles from windows 10 to ubuntu directory

where can I find the GUI of the ubuntu home directory which is installed from Windows 10 Microsoft store.  how can I move the files present in the C directory of windows 10 to one of the directory in the ubuntu


Apenas voy a iniciar con Ubuntu, básicamente que necesito saber de Ubuntu? respecto a las impresoras que hoy en día están instaladas en la compañía y con software que se trabajan, y que tipo de licencias pagas se requieren para trabajar Ubuntu, o antivirus requeridos. Agradezco la información que me puedan brindar.


Let $f$ be defined on the interval $I$. all we know about $f$ is that there is a constant $K\gt 0$ so that $|f(a)-f(b)|\le K|a-b|^2$ for all $a$,$b$ on $I$.  Q: show that $f$ is constant on $I$  hint: start with calculating the derivative using the definition?  how do I go about differentiating this inequality using the definition, and can I use $a=x$ and $b=x+h$ ? if yes then how


Infinitely many primes of the form $16n+1$?

As the title states I need to prove there are infinitely primes of the form $16n+1$ but I have absolutely no idea how to do it.


What type of memory module do I have - DDR3 or DDR 4 RAM?

I want to buy a RAM module for my laptop. I used the sudo lshw -short -C memory command and I've got this . I know everything about my RAM, except the type. I can see 4GIB SODIMM Synchronous 2133 MHz, but I don't know which one I need - DDR3 or DDR4?  Information from a Google research : DDR3 specifications started at 800 MT/s (or Millions of Transfers per second) and some went as high as 2133. DDR4, meanwhile, starts at 2133 MHz.


How to access hard drive using terminal?

I am new to Linux. I have installed Ubuntu distro. I would like to access the files on my internal hard drive using the terminal.  Can I use cd command to do so? Is there any other possible way using the terminal? (I want to learn to use the terminal)