How to write a simple scope for a Unity lens?

I am looking for a tutorial on writing a scope for simple search from a website.  is very complex.  If somebody can explain me the steps to write a scope in a simplest way, that would be very helpful.


Does assumption of normality of each mixture components implies that each margins is normal

I just would like to understand some information about the joint normality and the margins. I read that the normal joint distribution almost always implies that the univariate margins are all normal.   My question is:  1- Is this apply for Gaussian mixture models? For example, in the Gaussian mixture model, each mixture component follows a Gaussian distribution. Hence, does it imply that each margin will be a Gaussian distribution as well? "I understand that mixture components are used to describe the dependency structures, and they are the joint distribution. is that correct?  2- I read this from one answer to a question in this site . "So yes, the assumption of joint normality is a sufficient condition for all marginal distributions to be normal, irrespective of the dependence structure. Hence, the theory of Copulas does not affect this result in any way."  However, I really do not understand this: irrespective of the dependence structure. As I understand if the joint distribution in normal then the dependence structure is normal.   Could someone help me with my questions, please?


Novel/story about traders on a planet with no metal

I read this story around 1975. The main character traveled with some traders to a planet that had no metal, and that was being prevented from having any metal (I don't recall why). The planet's inhabitants were very ingenious in creating technology without metal. The part that sticks in my mind is when the main character went to a market with one of the traders, where they were attacked by the locals. The trader had obtained a local firearm which was almost entirely made of clay. The firearm's "trigger" worked a pump similar to a water gun, which built up air pressure inside the firearm. The firearm contained powdered coal, and striking a spark inside the pressurized firearm ignited the dust and propelled a dart.   I don't recall much of the plot, but I have always remembered that description of the firearm.


A problem in Bohr's day was understanding why an orbiting electron does not continuously radiate an EM field. An orbiting electron is a moving charge and according to Maxwell, this should generate an electric and magnetic field. Bohr said that photons (packets of EM energy) are only emitted when an electron jumps from a high quantum state to a lower one. Does that mean that an electron in a stable atom really isnt moving? Conversely, does Bohr's model mean that all motion requires energy transitions from one qunatum sate to another?


How to build a variation table with tkz-tab?

TikZ: variable in calc syntaTikZ: variable in calc syntax 1 x 1


Why are students being forced to memorize complicated proofs in Russia (and other Post-Soviet states)?

I'm not sure how well this question fits into MSE, but no other community (probably except mathoverflow) has as many mathematicians as MSE who might be able to answer this question.  In the departments of mathematics in Russia (and probably other post-Soviet countries) it is very common to have oral theoretical-oriented exams as opposed to written exams where one is offered to solve problems. For example, for a course in analysis, the students are expected to be able to reproduce proofs of all theorems in, say, Chapters 1-9 of Baby Rudin. At the same time, my experience has shown that many students are not able to apply e.g. the Implicit Function Theorem and they just learn proofs by heart. I wonder what's the point of making the students memorize proofs? How is the knowledge of the cumbersome proof of the Morse Lemma or the Rank Theorem (see the analysis syllabus below) supposed to be helpful? Of course, there are theorems whose proofs only test the knowledge of definitions, and it just impossible not to know their proofs for someone who understands what's going on. But what's the point of making everyone memorize conceptually hard proofs instead of testing the understanding?  Note that I do not deny the fact that one should read and understand proofs of whatever theorem that they are studying. Below I'm giving examples of theorems which the students are supposed to know (with proofs of course), restricting myself to the sophomore year. But the same is expected from freshmen. Mind you that there is no introductory "Calculus" courses, the first "analytical" course is real analysis (covering for example Zorich's book). I'm saying this to emphasize that the students who come from ordinary high schools have a hard time understanding the basics, and yet they are required to memorize complicated proofs as opposed to being able to work with the theorems.  I do realize that writing proofs is an essential part of a mathematician's job, but I find it much more reasonable to learn how to do proofs by solving proof-oriented problems as opposed to memorizing proofs of theorems that took the humanity hundreds of years to come up with.  Here are some examples (lists of theorems whose proofs the students (sophomores) are supposed to know), in Russian [but you can use Google Translate]:   ()


Use \scriptsize and shift a longtable to the left with revtex4

I have the following table:     \documentclass[a4paper,preprint,aps,                    unsortedaddress]{revtex4}     \usepackage[top=2.5cm,bottom=2.5cm,                 left=3.5cm,right=2.5cm]{geometry}     \usepackage{longtable,array,booktabs}      \ifdefined\mc        \renewcommand{\mc}{\multicolumn}     \else        \newcommand{\mc}{\multicolumn}     \fi      \begin{document}           \setlength\LTleft{-3.0cm}         \setlength\LTright{-2.0cm}          \scriptsize      \begin{longtable}{ l r @{--} p{1.3cm} >{\centering}p{2.6cm}                         *{4}{p{1.25cm}} p{2.1cm}}                    %% headers and footers      \caption{Table} \\      \hline\hline     \endfirsthead      \mc{9}{c}{\tablename\ \thetable\ -- \emph{Continued from previous page}} \\      \hline     aaaaaaaaaaaaaaaaaaaaaaaa & \mc{2}{c}{bbb--ccc} & ddd & eee & fff & ggg & hhh & iii \\     \hline     \endhead      \hline     \mc{9}{r}{\emph{Continued on next page}} \\     \endfoot      \hline\hline     \endlastfoot      %% body of table          aaaaaaaaaaaaaaaaaaaaaaaa & \mc{2}{c}{bbb--ccc} & ddd & eee & fff & ggg & hhh & iii \\     aaaaaaaaaaaaaaaaaaaaaaaa & bbb & ccc & ddd & eee & fff & ggg & hhh & iii \\     aaaaaaaaaaaaaaaaaaaaaaaa & bbb & ccc & ddd & eee & fff & ggg & hhh & iii \\     aaaaaaaaaaaaaaaaaaaaaaaa & bbb & ccc & ddd & eee & fff & ggg & hhh & iii \\      \end{longtable}     \end{document}   which I would like to shift to the left by setting \setlength\LTleft{-3.0cm}  and \setlength\LTright{-2.0cm}. Furthermore, I have to apply \scriptsize for the table. However, none of these commands are working with revtex4. Could you please provide a solution to this problem? (This question is the same as in , but I cannot sign up with that username.)  If it is not possible, an alternative solution would also be useful for me. For this case, I attached the first page of my real table.


I intend to initialize a list of list with length of n. x = [[]] * n  However, this somehow links the lists together. >>> x = [[]] * 3 >>> x[1].append(0) >>> x [[0], [0], [0]]  I expect to have something like: [[], [0], []]  Any ideas?


I computed the homology groups of the torus, can someone tell me if this is correct? The calculation, not the result that is. Thanks!  The cells of $T^2$ are $e^0, e^1_a, e^1_b, e^2$  The chain groups are  $$ C_0(T^2) = \{ k e^0 | k \in \mathbb{Z} \} = \mathbb{Z}$$  $$ C_1(T^2) = \{ k_1 e^1_a + k_2 e^1_b | k_1 , k_2 \in \mathbb{Z} \} = \mathbb{Z} \oplus \mathbb{Z}$$  $$ C_2(T^2) = \mathbb{Z}$$  $$ C_k(T^2) = \{ 0 \} , k > 2$$  Now the homology groups:  $$ H_0(T^2) = \ker \partial_0 / im \partial_1 = \mathbb{Z} / 0 = \mathbb{Z}$$  where $im \partial_1 = 0$ because there is no chain in $C_1(T^2)$ whose boundary is a zero-chain in $C_0(T^2)$. (Is this reasoning correct?)  $$ H_1(T^2) = \ker \partial_1 / im \partial_2 = \mathbb{Z} \oplus \mathbb{Z}$$  where $\ker \partial_1 =  \mathbb{Z} \oplus \mathbb{Z} $, i.e. again everything maps to zero because there is no element in $C_1$ whose boundary maps to an element in $C_0$.  $im \partial_2 = 0$ again because there is no element in $C_2$ whose boundary is an element of $C_1$.  I don't want to use Hurewicz to do $H_1$.  $$ H_2(T^2) = \mathbb{Z}$$ using similar arguments as above.  Thanks for your help.  Edit  I posted the computations as an answer below. I got two up votes but I don't know by who so I'm not yet sure I can trust them...


Roku "I have mastered the elements a thousand and one times and lived a thousand lifetimes"

Just wondering. How can there have been one thousand avatars in the course of 10,000 years. Must have had pretty long lifespans.  Quote to back this up. Jeong-Jeong saying to Aang:      You Are Weak   Avatar Roku says     You think i am weak?   Jeong-Jeong says     No, no. I did not mean that   Avatar Roku says     I have mastered the elements a thousand times and now I must do it again. You will teach the Avatar firebending.   Jeong-Jeong says


After submitting a site removal request with Google, the tool is showing severe health problems, how do I re-include my site in the index?

I had a major issue in the last week where a site was found to be showing huge numbers of pages that it shouldn't have been. Naturally Google indexed all of these pages!   Rather than manually remove 5000+ links, I thought the nuclear option of removing the whole site would be the best option (using the Remove URL tool with no URL provided), since the site was poorly ranking anyway.   I had read that this was a good way to reset your site if you wanted to start over.  I removed the site, then after confirming that Google had removed it, I resubmitted the site for indexing and submitted a new sitemap and a new robots.txt to prevent indexing of the restricted pages.  The sitemap shows that it is indexed (or at least, a large portion of it is indexed) and I can see the Googlebot activity on the site.  However, on my dashboard I see severe health problems listed, with the main one being important page removed and a link to the removal request for the main site.  Furthermore, there are no links to the site in the Google index (when tested against site:example.com in a search).  Do I need to reinclude the site using the removal tool? If I do this, will it re-add all the bad URLs that I was trying to get rid of?


the normal distribution as a special case of a student's t-distribution

I encountered the following three distributions of a continuous random variable, with the corresponding pdf's;  the normal(Gaussian) distribution $$f_{\mu,\sigma}(x)=\frac1{\sigma\sqrt{2\pi}}e^{-\frac12\left(\frac{x-\mu}{\sigma}\right)^2}$$ the Cauchy distribution  $$f_{x_0,\gamma}(x)=\frac1{\pi\gamma\left[1+\left(\frac{x-x_0}\gamma\right)^2\right]} =\frac1{\pi\gamma}\left[\frac{\gamma^2}{(x-x_0)^2+\gamma}\right]$$  the student t-distribution $$f_\nu(t)=\frac{\Gamma(\frac{\nu+1}2)}{\sqrt{\nu\pi}\; \Gamma(\frac\nu2)}\left(1+\frac{t^2}\nu\right)^{-\frac{\nu+1}2}$$  The formulas are all from wikipedia. And it says the first two distributions are special cases of the third one. Setting $\nu=1$ to the third pdf, we get the second pdf with $x_0=0$ and $\gamma=1$ very easily. The only nontrivial part of which is to evaluate $\Gamma\left(\frac12\right)=\sqrt{\pi}$, but  anyway. But how come are the first and the third related? Wikipedia says that the third 'approaches' to the first($\mu=0$, $\sigma=1$) as $\nu\to\infty$. But how? Can anyone give me a possible answer?


Comma after "intuitively" at the beginning of a sentence?

In the following sentence, do I have to put a comma after "intuitively?":     Intuitively, it represents the concept of something.


I just installed bash on windows. When I use sudo, sudo hangs

I know on linux when you use sudo, it wants a password.  Things I have already tried:  if i type sudo apt-get install g++ and hit enter, the cursor goes to the next line and no output happens. I thought the issue might have been apt-get, so i tried that without sudo, and got the error saying i might not be root. so that is working.  i tried typing sudo, hit enter, cursor goes down to the next line and nothing.  i can type in my password and it isn't ecnrypted. how do i fix this?


Simpler derivation of $\sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}$

I know that the equality $$\sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}$$ can be proved in numerous ways by using the Fourier series. However, is there a way to derive it using more fundamental tools? I've tried: $$ \sum_{n=1}^\infty \frac{1}{n^2} = \sum_{n=1}^\infty \int_0^1 x^{n-1} dx \int_0^1 y^{n-1} dy = \int_0^1 dx\int_0^1 dy \frac{1}{1-xy}$$  and by changing variables I was able to write it in several other forms:$$ = -\int_0^1\frac{\ln(1-x)}{x} dx = \int_0^\infty \frac{\ln (1+t)}{t(1+t)} dt = \int_0^\infty \frac{u }{e^u -1}du $$ but that's as far as I could get.  I specifically don't want to use Fourier series. More fundamental complex analysis, like contour integration, is fine.


I have 64 bit ubuntu 12.04 on my system. with nvidia graphic card. i installed some packages off line by using dpkg and also some programs from source code. now i have problem installing wine on my system. i have tried these commands:   sudo apt-add-repository ppa:ubuntu-wine/ppa sudo apt-get update sudo apt-get install wine1.7   but it gives me this:  The following information may help to resolve the situation:  The following packages have unmet dependencies:  wine1.7 : Depends: wine1.7-i386 (= 1:1.7.12-0ubuntu1) E: Unable to correct problems, you have held broken packages.   i have also tried aptitude:  sudo aptitude install wine1.7   one of the solution it suggests is this :       Remove the following packages:                                    1)      empathy                                                         2)      espeak                                                          3)      ffmpeg                                                          4)      gnome-media                                                     5)      gstreamer0.10-plugins-good                                      6)      indicator-sound                                                 7)      libasound2-plugins                                              8)      libav-tools                                                     9)      libavdevice53                                                   10)     libcanberra-pulse                                               11)     libespeak1                                                      12)     libfarstream-0.1-0                                              13)     libfluidsynth-dev                                               14)     libfluidsynth1                                                  15)     libjack-dev                                                     16)     libjack0                                                        17)     libportaudio2                                                   18)     libpurple0                                                      19)     libtelepathy-farstream2                                         . . .                                            Install the following packages:                                   40)     libcanberra-gstreamer [0.28-3ubuntu3 (precise)]                        Keep the following packages at their current version:             . . .                               63)     wine1.7 [Not Installed]                                         64)     wine1.7-amd64 [Not Installed]                                   65)     wine1.7-i386:i386 [Not Installed]                                      Leave the following dependencies unresolved:                      . . . 84)     wine1.7-amd64 recommends libasound2-plugins                     85)     wine1.7-i386:i386 recommends libasound2-plugins:i386            86)     wine1.7-i386:i386 recommends libsane:i386                       87)     wine1.7-i386:i386 recommends libxcomposite1:i386                88)     wine1.7-i386:i386 recommends libxcursor1:i386                   89)     wine1.7-i386:i386 recommends libxi6:i386                        90)     wine1.7-i386:i386 recommends libxinerama1:i386                  91)     wine1.7-i386:i386 recommends libxrandr2:i386                    92)     wine1.7-i386:i386 recommends libxrender1:i386                   93)     wine1.7-i386:i386 recommends libxt6:i386                        94)     wine1.7-i386:i386 recommends libxxf86vm1:i386     as it shows aptitude is going to delete many unrelated packages and not installing wine. i don't know how resolve this dependecy problem. i could install wine on newly installed ubuntu but in my case i don't know what packages are causing this problem. i also tried other version of wine such as wine wine1.6 wine1.4 wine1.3. i also tried installing wine from source code but it only can run non gui applications.


redirect www to http AND root to subdirectory in .htaccess

Not sure I am posting at the right location :)   I want to be able for instance to redirect . example.com (with www) to http:// example.com/fr (without www, AND subdirectory)  Of course, I also want http:// example.com to redirect to http:// example.com/fr   What I have so far is this :  RewriteBase / RewriteRule ^index\.php$ - [L]  RewriteCond %{HTTP_HOST} ^www.example.com [NC] RewriteRule ^(.*)$ example.com/fr/$1 [L,R=301,NC] RewriteCond %{HTTP_HOST} ^example.com [NC]  RewriteRule ^(.*)$ example.com/fr/$1 [L,R=301,NC]   It does a permanent loop though...  How can I fix this ?   Thank you ! :)


Let $a \in \mathbb R$ and let $f$ be a real-valued function defined on an open interval $J$ containing $a$. Then $\lim_{x \to a} f(x)$ exists if and only if the left-sided limit and the right-sided limit of $f$ exists and $\lim_{x \to a^+} f(x) = \lim_{x \to a^-} f(x)$  I want to ask how to prove this proposition converse direction? That is, assume $\lim_{x \to a^+} f(x) \neq \lim_{x \to a^-} f(x)$ but $f$ is continuous at $a$?


How to deal with cheat avoidance and trusted client issue

I hope not to be off-topic here.  At the moment I'm dealing with networking programming for the game I'm working on and I found different possible scenarios.  I started to build code using a Platform as a Service such as Photon Unity Network which offers a quite simple system to sync players through its cloud.  The problem is that by using the cloud you must have at least a trusted client in order to prevent cheating from players.  I wish I could learn what is best to deal with this problem considering that opting for a client/server structure would be the best but I'm a bit worried about rental/purchase pricing. Is there a cheap way to have a working game server?


Any group of order $15$ is abelian(without sylow theorem)

Prove that, any group of order $15$ is abelian (without help of Sylow's theorem or its application).  What I have done so far is,   by class equation we know that $|G|=|Z|+\sum\frac{|G|}{C(a_i)}$. Now if I can show that $|G|=|Z|$ then the theorem is proved. Now order of $|Z|$ can not be $3$ or $5$, because if it is then $(G/Z)$ will be cyclic,which can not be since $G$ non-abelian.So, only possibilities are $|Z|=1$ or $15$. Now haw can I conclude that $|Z|\not=1$?


What does it mean by a^b in real number system? How is it defined mathematically? It is clear in case of exponent being an integer. i.e., a real number a is multiplied b times where b belongs to Z If b is a rational..say b=p/q, then a^b can be interpreted as a^(1/q) multiplied p times. But how is it defined when b is irrational?


Trig limit without L'Hospital Rule: $\lim\limits_{x\to0}\frac{\tan x-\sin x}{x^3}$

I'm really getting stuck on this and would appreciate some help:  $$ \lim_{x\ \to\ 0}\left[\,\tan\left(\,x\,\right) - \sin\left(\,x\,\right) \over x^{3}\,\right]  $$ I know I need to change $\tan\left(\,x\,\right)$ into $\sin\left(\,x\,\right)/\cos\left(\,x\,\right)$  and turn $\sin\left(\,x\,\right)$ into $1 - \cos^{2}\left(\,x\,\right)$.  But then I get stuck.


I would really like to switch over to Thunderbird from Evolution. I have had a look around and haven't found a good up to date how to for migrating. I have quite a lot of emails and filters and would like to make the transition as painless as possible.  thanks for any help.


What's the difference between TRUNCATE and DELETE in SQL?  If your answer is platform specific, please indicate that.


do specialst fields have their own colloquial vocabulary not shared by laymen?

I saw the following passage in a PSAT study guide. One of the questions is about the use of the term 'hot spot'. Can we say it's being used colloquially and technically at the same time? The question amounts to whether colloquial language is necessarily a part of laymen's terms.  Geologists call these volcanic areas hot spots. Lying deep in the interior of a plate, hot spots or intra-plate volcanoes are sources of magma, the red-hot, molten material within the earth's crust.


Requesting some research study problems on Classical Mechanics

Someone please tell (advice) me some research study problems on Classical Mechanics that can be tackled with Undergraduate level knowledge.


Troubleshooting Powershell errors from SQL Agent job

I have a powershell script that I am trying to add in to a sql agent job, but the job step is failing with the following error      A job step received an error at line 1 in a PowerShell script. The corresponding line is 'import-module SQLPS  -DisableNameChecking'. Correct the script and reschedule the job. The error information returned by PowerShell is: 'Could not load file or assembly 'file:///C:\Program Files (x86)\Microsoft SQL Server\130\Tools\PowerShell\Modules\SQLPS\Microsoft.SqlServer.Management.PSSnapins.dll' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.   I assumed that the error was being caused by differences in the module path, so I explicitly set the path via $env:PSModulePath to match the path of my powershell session where the code runs fine.  I am pretty new to powershell, so any help you could provide would be appreciated  I am just doing some testing right now, so everything is running locally on my desktop.  I am running SQL Server 2012.


I have a content type with multiple fields. Some of the fields are accessible to everyone and there are other fields for which the access is controlled.   Example: There is a content type called Reports with fields like title, summary, body etc. Title and summary should be visible to everyone but the access to body field is controlled.  For implementing this I need to have 2 view modes. one of them will have the fields title and summary displayed with the rest of the fields hidden. The other view mode will have only the body field visible. I am planning to implement the hook hook_node_access to derive the access permissions for the node. So how can I get the view mode in this hook so that I can have my access check based on the view mode.


Should there be a place to ask about programming libraries and technologies?

Bjarne Stroustrup once mentioned in one of his bigthink interviews that one of the greatest problems most programmers have is not finding or using the right libraries.  On stackoverflow and programmers, I've observed a trend towards questions like "I want to do this, is there a [library | programming language] for that", or "I have these {n} [library | language] candidates for my project; which one would yield me the least amount of headache given these requirements".   Since questions like these aren't exactly programming questions in the sense of "this code should do this, but it does this, why?", they are often (though not always) being closed as "not constructive" because they do not have a definite answer (which is true, and according to the FAQ they would be off-topic on both stackoverflow and programmers).  Nonetheless, I think library questions are valid, and that it is helpful for any programmer to receive independent input from experienced programmers (at least it helps me a lot every time I browse through one of those closed questions, which I found through google). Does anyone agree that posting library choice questions should be explicitly allowed on either stackoverflow or programmers?


Is there a away to test if a player isn't moving?  At the moment I have put this command on a hopper clock:  /scoreboard players set @a sneak 3    But that doesn't seem to work because in another command block I am testing for a score of three, and every tick it summons a block even when you're moving.  I am using this for a vanilla block hunt so when your not moving you become a solid block.


This may be a bit of a stupid question, but I wanted some RAW clarity on this spell regarding whether or not the fire creates light or not.   Within the body of the spell's description, nowhere does it state that the wall of fire creates any sort of light. This may seem counterintuitive, but I know that plenty of spells involving flame that specifically designate that they shed some form of 'bright' or 'dim' light. A few examples:  Fire Shield     Thin and wispy flames wreathe your body for the duration, shedding bright light in a 10-foot radius and dim light for an additional 10 feet. You can end the spell early by using an action to dismiss it.   Flame Blade     The flaming blade sheds bright light in a 10-foot radius and dim light for an additional 10 feet.   Flaming Sphere     The sphere ignites flammable objects not being worn or carried, and it sheds bright light in a 20-foot radius and dim light for an additional 20 feet.   Continual Flame     A flame, equivalent in brightness to a torch, springs forth from an object that you touch.    You get the picture. I know that spells like Fireball or Flame Strike have no light descriptions either, but I find Wall of Fire more suspect because this spell has a 1-minute duration.   Does Wall of Fire shed light?


why I cannot use forward declaration when using template？

for non-template class, I can use forward declaration in the header file. But it gave me error when I use it in the template class.  I have to include the header file, I would like to know the reason.  class Pu;  template <typename T> class Pt() {      void test(Pu<T> u); }


Can I use SPI for asynchronous serial input?

I need a second serial async input channel on the MSP430G2553 and would like to use the SPI USCI to do this.  Is the USCI SPI baud rate stable enough to do this at 300 baud, 2400 baud or 9600 baud? I am currently using the 8 MHz clock.  Is there any other option that can save me from bit-banging?  Might it be possible to do asynchronous receive by starting the clock-out when the start-bit is received?   My current thinking for Rx on the SPI at 300 baud is as follows:   start bit interrupt disable wait for 1/2 bit do Rx enable Rx interrupt start bit interrupt enable   One can use 10 bit receive on some of the other members in the family that contains a SPI.  Please note that this is a similar question to:  but the answer is much more complex because the SPI clock output must be aligned with the Rx bitstream.  Only half duplex is possible if you want to do Tx the same way.  Thanks.


There is a song but I am not sure about the meaning of "make it last" in that song. Please let me know what it means and which situation I should use this?  Make it last - Tim Mc Morris


Google search results snippet for our site is a warning about not being able to play HTML5 video

All of a sudden, without any change in the index.html, our site is showing up in Google search results (on multiple browsers and devices) with Google Preview text that, instead of giving a summary of our site, now says:     Your browser does not currently recognize any of the video formats available. Click here to visit our frequently asked questions about HTML5 video.     We have a YouTube embed on our homepage that does include an html5 parameter in the media URL link in the embed, but there are no issues playing the video with any browser and device we can find.  What would suddenly cause this text to appear in Google search results?   We are using the  tags as the metatags in the <head> of our webpage and do indeed have title and description tags.    To mimic the behavior of Googlebot, I installed Windows on a VM and got Chromium 41 running. I get the same Google Preview text with the html5 video message when the site comes up in Google search results using this browser.    When I view the site in Chromium 41, I see the YouTube embed and it renders on the page and plays with no issue, just as with all other browser and devices we've tested on. The only time we see this message is in the Google search results, not on our actual site.


I want to change my cursor in wpf to an custom .cur file?

I want to change my mouse pointer to an custom cursor in my application.  So when my application starts, i want the custom cursor, and when it stops i want it gone.  How to do this in c# behind the code in wpf?


Unrelated downvotes because of criticism

So basically on a  I attempted and failed to answer, I have been following it because I am interested in the solution. People have been posting answers to solve it (some similar or identical to mine). Since I've been looking at the problem the whole time I felt an obligation to tell some people they were incorrect (maybe a bit too insistently). However after one of my corrections, I noticed my reputation suddenly drop; when I looked at the cause I noticed that two of my questions (which is all of them btw) had been simultaneously downvoted. The chances of that are very slim (since the questions have no recent activity) so I assume someone got angry at me correcting them and decided to lower my rep.    My question is:  is there any recourse for this or any way to tell if I am just being a suspicious person?


What is the expected amount of time it takes to first observe a triple for multiple dice rolls?

Assuming we have a fair die, we toss a die multiple times. Also assuming that a triple is defined as when we have three rolls in a roll that result in the same number, and that the rolls are independent, what would be the expected time until a first triple is observed? The answer I have in a book is rather heuristic. It briefly states that if you take 1/36 as the probability of observing a triple at time t>2, then the formula for the time until the first triple should be: $36 = \frac{1}{6}+\frac{5}{6}X$, where $X =$ first time a triple is observed.  I was wondering if there was a more formalistic way of coming up with the answer. Thank you!


I know, correct me if I am wrong, that the functions $H_n(x)\exp(-x^2/2)$ form a complete basis in $L^2(\mathbb{R},dx)$, where $H_n(x)$ is the $n$th Hermite polynomial. This must be true also for $x^n\exp(-x^2/2)$ with $n\in\mathbb{N}_0$. Does someone know a proof of the latter or can give me a reference? Since I am not a mathematician, I will really appreciate it if the proof contains all the details that might puzzle a non-mathematician.  I also have the problem to choose functions $f_k$ such that  \begin{equation} \int_{-\infty}^{+\infty}f_k(x)x^n\exp(-x^2)dx = \delta_{kn} \mbox{.} \end{equation}  Does anyone know a method to construct the $f_k$s?


How does gravity work on Star Wars ships?

Inspired by the question , how does gravity work on the Millennium Falcon and other ships its size? The passengers are not strapped in and regularly move around just easily as they would on a planet with Earth's gravity.   The answer for the Death Star refers to gravity often being "coreward" (presumably taking advantage of the natural gravity an object of such substantial mass would have), but that doesn't apply for a small ship. So how is gravity accomplished?


I am on Windows Server 2008 R2, and disabled the enhanced security configuration for IE in server manager.  I have since upgraded to IE 9, and can no longer disable it.  It is set as disabled in server manager, yet it is still very much enabled as evidenced by the warning whenever I visit any site.  How can I actually disable this feature?


Suppose n is even positive integer and $H$ is a subgroup of $\mathbb Z_n$

Suppose $n$ is even positive integer and $H$ is a subgroup of $\mathbb Z_n$. Prove that either every member of $H$ is even or exactly half of members of $H$ are even.  Same question have been asked , but I ask it again because I do not understand answers because of concepts like isomorphism and cosets etc. Need a simple answer.  Thanks


I'm wondering if there's an solid way (not a hack) to remove transparency from a photoshop layer? I know the usual, hacky way is to duplicate and merge a layer around 8 times or more to reach a fully opaque result (with the exception of areas with 100% transparency). But this just doesn't sound right, maybe there's an option to do this without such a convulted method that I don't know about.  Here's an example:


Find an example of a commutatice unital ring $R$ and an $R$-module such that $\text{Ass}(M)=\emptyset$

Find an example of a unital commutative ring $R$ and an $R$-module $M$ such that $\text{Ass}(M)=\emptyset$.   Recall that   $\text{Ass}(M)=\{p\in\text{spec}(R):\exists 0\ne m\in M:\text{ann}(m)=p\}$. $\text{ann}(m)=\{r\in R:rm=0\},\forall m\in M$.   I thought of $R=\mathbb Z$ and $M=\mathbb Z/n\mathbb Z$, which doesn't work.


Formatting problem seen in suggested edit

The link kindly provided by @animuson in the comments explains why it happens with eight blanks instead of four, but my question is, why does something which is not markup, but looks a bit like markup, get treated as markup.  I had assumed that questions regularly included code minus whitespace (it saves the code so much time to write, if not someone to read later) and thought it may be unique to the editing box. It is not.  So, the question remains, why does a<b, with no closing < even, get treated as markup. Is it possible for the edit box to say "this isn't really markup, so I'll display it"?   In addition, the second set of code in a "list" in the same question does not behave in the same way. This only require four leading spaces, not eight. Is it because it is 1.text rather than `1. text'. Yes, looking now, it seems so.  The list formatting requires a space after the full-stop/period. Is this correct? The OP edited both "item 2's", but only one broke.  If "1. Text" is to be automatically treated as a formal list, without original author or editor probably being aware, should "1.Text" be treated in the same way?  This suggested edit, , looked like the suggester had killed some code (look at the first point 2).  Having previously learned that looks can be deceiving, and to use both the views on the Review screen, it seems that all the scrunched-up code got the <kidsArray.length;k++){ treated as the start of an html-style tag. So the rest of that code block disappeared.  Tricky, and the editor should have looked at the preview part of the edit screen and noticed the problem. Correctly rejected, and I edited/rolled back to confirm that the edit pickles the question.  The original seems to work because it has eight leading blanks. Change that to four, and it goes to pot. In fact, change it to seven. It is fun toggling between seven and eight leading blanks and watching the code disappear and reappear. OK, fun for a while.  There's even more fun. In attempting to prepare some screenshots of the here's-the-code-where's-the-code? scenario, it seems that the automatic list numbering may be causing a side-effect, or it may be the tabs in the original or something else, or some combination. Basically lots of different things happen when I mess with the post in the Edit box.  I can get the code to disappear (from the < onwards). I can get it to reappear again, or reappear as plain lines of text.   It is such a mess, I don't have time to do justice to the screenshots.   If others have a play (I was deleting most of the text above and below to make a smaller screenshot, replacing tabs by space, removing spaces (or tabs, not sure) on the second line of the code block) perhaps I can get some confirmation that I'm not going nuts. There's at least four different behaviours, and life isn't long enough for one person to recreate them all when they should be cooking dinner :-)


I'm using this , see my fiddle .  My problem is the method itemAdded is not working on newly added input.  $('input').on('itemAdded', function(event) {      alert('added'); //doesn't work on newly added input })   How to bind it the with body tag?


Why doesn't this regex work in Python 3?

I'm trying to match (.)\1+ in google. This works just fine on , but when I try this code in Python, r.match(s) returns None.  import re  s = 'google'  r = re.compile(r'(.)\1+')  print(r.match(s))


General formula for distinct k colourings of a regular n-gon

Suppose we are to colour edges of a regular n-gon with k-colours. How do we count the number of such distinct coloured n-gons?  I know that one way to count these is to use burnside's lemma, but im not able to apply it.


Equivalent word which represents 'Team' or 'Individual'

I am developing a coding contest project with multiple contests. The participants can be a team or an independent individual, depending on the contest setting. I want to define only one model for the participant which could understood as a team or an individual. Is there a word that can be used for team and participating individual? Update I am thinking to chuck the idea of implementing whole project based on smart team management complicating it whole and decided to implement separate team management and complicating that. But I would be very happy to change my mind if I could get a word, maybe even in some other language for this.


How do I prove these matrices have the same rank?

Let $A$ be an $n \times m$ matrix and let $T_A : \mathbb{R}^m → \mathbb{R}^n$ be the linear transformation $T_A(x)=Ax.$ Also let $B$ be an invertible $m × m$ matrix and let $C$ be an invertible $n × n$ matrix.  How do I prove that prove that the matrices A and CAB have the same rank?  I was thinking of using the rank-nullity theorem but I don't see how that would work.


Alas, I have found my posts in need of visual accompaniment and yet, I find not the mechanism to attach such images herein.  How, fine people of the support to Stack Overflow, does one attach a .png or .jpg file to their post?


I saw  post on how to solve $3^{123}\pmod{100}$ using Euler's Totient Theorem. How about for $3^{99}\pmod{100}$? It seems more complicated because applying Euler's Totient Theorem gets us $3^{40}\equiv 1\pmod{100}$. This means $3^{80}\equiv 1 \pmod{100}$, which isn't enough, because we still need to find $3^{19}\pmod{100}$. Now, when the terms are listed, a pattern does emerge. $$\begin{array}{|c|c|c|c|} \hline 3 & 9 & 27 & 81 \\ \hline 43 & 29 & 87 & 61 \\ \hline 83 & 49 & 47 & 41\\ \hline 23 & 69 & 07 & 21 \\ \hline 03 & 89 & 67 & 01 \\ \hline \end{array}$$ And $3^{19}$ ends in $67$. But how can I find this in other methods, besides bashing? Is there some sort of theorem that I can use?


A word or phrase meaning 'paying an unhealthy amount of attention to something you like/want'.

The context would be in a romantic pursuit or a job opportunity - you've applied for the job and are waiting to hear back from them - you're constantly checking your emails, you're calling the receptionist to ask why they haven't got back to you (way to spoil your chances), etc.   Is there a word or phrase to describe this state.   Example usage might be a friend saying:      I think you're [over focusing] on this opportunity here. Maybe it'll all work out well - but in the meantime you should divert your attention somewhere else.


Installing Windows XP to and running from an USB drive

Before you tell me to google around, trust me I did and nothing worked for me. I must be missing something.  I have a small PC with limited storage options. I have a small internal hard drive and 8GB usb stick. I can't fit the Windows XP install on the internal hard drive. So I'm trying to install it to the usb stick and make it boot.  BIOS recognizes the usb stick, also the Windows installer listed it in the partition list. It said I need to make MBR on the internal drive and use it to load OS from the usb stick, so I confirmed that, it copied some files etc, standard installation. But then after reboot I get the loading bar and after a second or two I get a BSOD with stopcode 0x7B (INACCESSIBLE_BOOT_DEVICE).  I checked the usb drive on another computer, the windows folder etc is there, partitions look alright. Next I checked the internal drive from linux liveCD, there is pretty much just 3 important files, ntldr, ntdetect and boot.ini.  Now, the boot.ini says: multi(0)disk(0)rdisk(0)partition..., I'm not sure if there is some special way to address usb partitions but I couldn't find one.  Looks like the bootloader on the internal drive is just unable to mount the usb stick and start the system. Although for that brief moment of time before BSOD the stick's led is flashing, but that might just be some BIOS usb initialization.  I got an idea to maybe use a different bootloader (grub?) on the internal drive but I'm not sure how to do that.  Any advice and pointers are appreciated. If you have any questions about details I left out, please ask in the comments and I'll try to answer.


In DS9's Paradise Lost episode (season 04, episode 12), the plot is heavy with Starfleet intrigue: Sisko discovers that Admiral Leyton is plotting to take over control of Earth and put it under a military rule. His options seem limited to convincing the President of the United Federation of Planets of the plot, or convince captains working for Leyton to stop obeying orders. This raises the question: are there no other admirals that he could have gone for and convinced that Leyton was a traitor? Are there no people of higher rank, fleet admirals maybe? We know that there are , and presumably a number of those are stationed on Earth, since Starfleet Headquarters are there. Why aren't we seeing any? This makes me wonder about a broader question: how does Starfleet governance works at the highest levels of the hierarchy? There seems to be a commander in chief (e.g. in season 1 of Picard, Fleet Admiral Clancy seems to hold that position?), but who appoints/elects them, how long is their term, and are there mechanisms for their early removal?


I have studied physics for about three years at university but after these years I still don't know how Newton derived his laws.  I know that he tried to find the best model to describe the motions  but It's a bit hard to believe for example how did he knew that an object can move at constant velocity without an external force? how he could be sure about that?!  Or, how could he derive his third law?, there was no instrument to measure forces or velocities..., he couldn't lie on the observations without any reliable data. Should I consider his laws as principles?!


Nautilus does not show the left bar, how do I turn it back on?

When I open nautilus does not open the left bar where it says computer and down markers such as music, documents, videos, downloads. I reinstalled nautilus from the synaptic package manager but nothing happened. What I can do to make that bar visible again?


Does Battlefield Forge add two mana to your pool each time it is tapped?

Do cards like  add 2 mana each time it's tapped or is it just one of the two tapped mana options? Or can you choose between both at once vs one? And is the mana only there while it's tapped?   {T}: Add {1} to your mana pool.  {T}: Add {R} or {W} to your mana pool. Battlefield Forge deals 1 damage to you.


Is there a flaw in whole disk encryption vs volume or folder encryption?

My company just implemented whole disk encryption on all laptops () and the concept seems flawed.  Please correct me if I'm wrong, but if I have known file in plain text and that same file in encrypted text, it possible to use that information to find the key for decryption.    If there is a better stack to ask this question on, please let me know and I'll repost.


Stack Exchange is free to use , so how does it earn money?

I don't paid for using Stack Exchange communities, so how they make money to support it all?


Update Migration Path List for Non-Moderators

Currently the migration path options from SO are:   Meta.SO Serverfault SuperUser Webmasters Programmers   If we are going to be limited to 5 options, shouldn't we periodically re-evaluate which sites are most appropriate?   (10k only) indicate that the top sites for the last 90 days are:   Superuser - 564 - 5% rejected ServerFault - 278 - 10% rejected Tex - 157 - 13% rejected DBA - 144 - 2% rejected Sharepoint - 127 - 1% rejected Programmers - 126 - 26% rejected CodeReview - 100 - 3% rejected Meta.SO - 81 - 18% rejected Wordpress - 75 - 14% rejected Webmasters - 58 - 8% rejected   All these migrations for sites out of the list required a flag and a moderator to process it.  This is just extra work for the mod team!  If we had the top 5 destinations by volume as the 5 options, we would have had a net savings of 160 flags to be processed.  I suspect we will actually see these numbers change quite a bit if it's easier for users to put questions in the appropriate spot without moderator intervention.  Can we have a review of the migration path list based on migration volume?  Think of the flags!


Lubuntu 12.04, need updates while roaming

I installed Lubuntu 12.04 while I am roaming on old Dell Inspiron Pentium 4 with 1GB ram and integrated Ati graphics because I read that this distro handles 720p and more videos. Well, it looks like I was wrong because Mplayer keeps crashing. I started to think that if I update it may fix the problem. Okay, so I have data roaming but not tethering/hotspot, nor the money for it. Is there a way to download my updates to my phone (185MB approx.) then transfer to my laptop?


How to only keep BMP in the utf-8 text file?

This is the content of a text file, and I want to only keep BMP.  这是无效的字符  𡛂 这是正常的字符  哈   In the , I find there is a solution, but it doesn't work here.  iconv -f utf-8 -t utf-8 -c test.txt     The utf-8 of 𡛂 is F0A19B82 (located in CJK Unified Ideographs Extension B), utf-8 of 哈 is E59388（located in CJK Unified Ideographs).  If I want to delete all characters(the size greater than 3 Bytes) like 𡛂 in text file , how to do it?


How can I launch screensaver with a keyboard shortcut?

I've looked around but can't seem to find any good answers. Would appreciate any pointers.


I want to make a cloze test using LaTeX. My Idea was to use the \phantom command to produce the space:  Some text \underline{\phantom{some text to complete}} some more text.   Now the problem is that \phantom seems to handle "some text to complete" as one word and does not break lines.   \documentclass{minimal}  \begin{document}  Some text \underline{\phantom{some  text to complete some  text to complete some  text to complete some  text to complete some  text to complete some    text to complete some  text to complete}} some more text.  \end{document}


Installing a program in its entire default installation program (without being asked anything)?

To install programs in Ubuntu I usually do sudo apt-get install <program_name> -y.  There are some particular programs I install that ask me non-password configuration questions.  For example, after doing sudo apt-get install postfix -y I was asked for particular Postfix set of configurations, although the default was just fine to me.  How can one make sure an install that asks non password question won't ask it nothing? Surly, the only reason is to automate a few, particular installation processes.  Note: The solution I seek is per program, not global.


Sorry for the silly question... :)  I found this statement in a query:  select * from table a, table b WHERE a.id =b.id(+)   What does the plus between brackets mean?  Thank you


Have executable, but need to identify source code

I am working in legacy code with the author long gone and documentation completely absent. I have an application running in production that I am trying to track down the source code in Team Foundation Server. I have been unable to find it in the AssemblyInfo.cs of the projects I have looked at.  Does anyone know where to look or how to search to find which solution makes that executable? I have found no similar questions in searching here.


is it possible to use FTP in DOS operating system?

is there a possibility of networking in DOS6.22, and can I use FTP in DOS operating system?


No installation candidate error when trying to install python-pypdf

I need install python-pypdf. So I tried to install it with:    sudo apt-get install python-pypdf   But I get this error:  E: Package 'python-pypdf' has no installation candidate   Why?


Is PCA unstable under multicollinearity?

I know that in a regression situation, if you have a set of highly correlated variables this is usually "bad" because of the instability in the estimated coefficients (variance goes toward infinity as determinant goes towards zero).  My question is whether this "badness" persists in a PCA situation.  Do the coefficients/loadings/weights/eigenvectors for any particular PC become unstable/arbitrary/non-unique as the covariance matrix becomes singular?  I am particularly interested in the case where only the first principal component is retained, and all others are dismissed as "noise" or "something else" or "unimportant".  I don't think that it does, because you will just be left with a few principal components which have zero, or close to zero variance.  Easy to see this isn't the case in the simple extreme case with 2 variables - suppose they are perfectly correlated.  Then the first PC will be the exact linear relationship, and the second PC will be perpindicular to the first PC, with all PC values equal to zero for all observations (i.e. zero variance).  Wondering if its more general.


VLANs using one managed switch or link router to unmanaged switches?

I'm the resident IT guy in an office with about 20 workers, amongst 3 separate companies who sublet an office.  We are wired with 24 ethernet ports dotted around the offices that all lead to a patch panel in my office. They are connected to 4 unmanaged switches into our ISP-supplied, cheap, router. (Internet is provided by a regular ADSL2+ provided by BT in the UK).  The problem is we are all one network, despite being separate companies, which is a security concern so we want to separate the logical/virtual networks (presumably, VLANs), but our current basic router doesn't support port-based VLANs.  I'm consider two options to isolate the networks, and I'd like advice which will do the trick:   A enterprise 4-port router (perhaps a  or ) that supports port-based VLANs, and plug our existing unmanaged switches into that:   (obviously, I would restricted to 3-4 VLANs, but that's fine Or, a large 24-port managed switch (like a Cisco), that supports allows me to define which of it's many ports belong to which VLANs.   I understand that this can just work in a "router-on-a-stick" configuration. Crucially, my network cupboard is too small to fit a typical 24 port switch, It's only got about 22cm depth.


What is the difference between encrypting and signing in asymmetric encryption?

What is the difference between encrypting some data vs signing some data (using RSA)?    Does it simply reverse the role of the public-private keys?    For example, I want to use my private key to generate messages so only I can possibly be the sender.  I want my public key to be used to read the messages and I do not care who reads them.  I want to be able to encrypt certain information and use it as a product-key for my software.  I only care that I am the only one who can generate these.  I would like to include my public key in my software to decrypt/read the signature of the key.  I do not care who can read the data in the key, I only care that I am the only verifiable one who can generate them.  Is signing useful in this scenario?


The people say that the value measured for the Hubble constant for the  CMB is 4.4 $\sigma$ away from the value measured by Type Ia supernovae. I don't get it  The value for CMB is $H_{0} = 67.4 \pm 0.5 km s^{−1} Mpc^{−1}$ while for Supernovae $H_{0} = 74.03 \pm 1.42 km s^{−1} Mpc^{−1}$.  If I do some easy calculation (taking the mean value of $H_{0}$ as the real value for $H_{0}$ and $\sigma$ as the value measured by Supernovae  )  I get  $$\sigma=\frac{74.03-67.4}{1.42}=4.66$$  I think that is to far from $4.4\sigma$. What I am doing wrong?


I am having trouble with understading how inverse totient function works. I know it can have multiple solutions but I don't understand how to find all of them for bigger numbers. For example how would one approach to problem of solving this equation:  ϕ(n) = 180  I do understand that one should represent ϕ(n) by product rule and somehow conclude numbers by combining product rule expression for ϕ(n) to get all numbers n. But it seems as very long process that I don't understand. My question is how I should think when looking at prime numbers expression for ϕ(n) and how should I eliminate some results? I was trying searching other similiar question and I still can't find some general algorithm for solving this problem.  Thanks!  EDIT: I would like to know how to calculate this problem by hand


Is there any way in SQL Server to get the results starting at a given offset? For example, in another type of SQL database, it's possible to do:  SELECT * FROM MyTable OFFSET 50 LIMIT 25   to get results 51-75. This construct does not appear to exist in SQL Server.    How can I accomplish this without loading all the rows I don't care about?  Thanks!


Most pythonic way to specify which object function to use in a function

I am setting a function where the user can specify how to initialize a variable. Here is a minimal example  def setValue( typeOf ):     if typeOf == 'normal':         a = np.random.normal( parameters)     if typeOf == 'uniform':         a = np.random.uniform(parameters)   However, in my real case, there are dozens of initialization options. I am wondering if I can make the code more elegant my specifying directly how the user wants to initialize the variable   def setValue( something ):     something hapenng     a = np.random.whatever_user_specified


I just installed Ubuntu 18.04 this day. Everything is fine until my screen froze and did not come back. So I restarted my computer and when it booted, my Login screen was different. Sadly I couldn't make a screenshot of it. But I can describe how it looks, so I hope this can help. It has a rectangular box in the middle. It says "Welcome to ", it has a login form for my username and password and it has an Ubuntu logo on the side.


Possible to connect 3 external monitors to Macbook Pro 15" (2017) via the USB-C ports?

I need to connect 3 external monitors to my Macbook Pro 15" (2017 version). I need the desktop to extend independently to the 3 monitors (the laptop lid will be closed, so only the external monitors will be displaying image). I can't find a clear answer online, but so far I don't know if it's possible to do that, even if connecting each monitor to a separate dongle. Is the OS able to recognize the 3 monitors as independent A+B+C? Or will it mirror A+B+B? I also need to be able to have them independently load color profiles for each monitor's calibration. Thank you guys. Cheers


Why would one suppress the intercept in linear regression?

In a number of statistical packages including SAS, SPSS and maybe more, there is an option to "suppress the intercept". Why would you want to do that?


Ok so I've been watching some videos about black holes but there is one thing I don't get: how can light be bent by black holes since photons don't have any mass?


Alice and Bob want to agree on a bit $0$ or $1$. Both know it would be fair to pick that at random, but there's no way they could meet to throw a dice and no third party they could trust. Are there known protocols that allow either side to prove that they did not manipulate the outcome?  My idea is: Both randomly (or not - but that would be in their best interest) pick $0$ or $1$, write it down, put it in an envelope and send it to the other person. Then the XOR of both bits could not have been manipulated unfairly by either party.  The problem I see with that: How can Alice prove to Bob that she did not open his envolope before making her choice?  Maybe one could instead choose an initial string $n$ and use the first $k$ with $f^k(n) < a$ as the chosen value. Now if $f$ is a cryptographic hashing function and $a$ is small Alice would have taken a long time if she were to predict $k$ before sending her own choice.


What is the difference between integration and unit tests?

I know the so-called textbook definition of unit tests and integration tests.  What I am curious about is when it is time to write unit tests... I will write them to cover as many sets of classes as possible.  For example, if I have a Word class, I will write some unit tests for the Word class.  Then, I begin writing my Sentence class, and when it needs to interact with the Word class, I will often write my unit tests such that they test both Sentence and Word... at least in the places where they interact.  Have these tests essentially become integration tests because they now test the integration of these 2 classes, or is it just a unit test that spans 2 classes?  In general, because of this uncertain line, I will rarely actually write integration tests... or is my using the finished product to see if all the pieces work properly the actual integration tests, even though they are manual and rarely repeated beyond the scope of each individual feature?  Am I misunderstanding integration tests, or is there really just very little difference between integration and unit tests?


I am a high school student who was playing around with some equations, and I derived a formula for which cannot physically imagine. \begin{align} W & = \vec F \cdot \vec r \\ \frac{dW}{dt} & = \frac{d}{dt}[\vec F \cdot \vec r] = \frac{d\vec F}{dt} \cdot \vec r + \vec F \cdot \frac{d\vec r}{dt} \\ \implies & \boxed{P = \frac{d\vec F}{dt} \cdot \vec r + \vec F \cdot \frac{d\vec r}{dt}} \end{align} I differentiated Work using its vector form formula $\vec F \cdot \vec r$ So I got this formula by applying the product rule. If in this formula $\frac{d\vec F}{dt}=0$ (Force is constant), than formula just becomes $P = \vec F \cdot \frac{d\vec r}{dt}$ which makes total sense, but this formula also suggests that if $\frac{d\vec r}{dt}=0$ then the formula for power becomes $P =\frac{d\vec F}{dt} \cdot \vec r$, which implies that if the velocity is zero that doesn't necessarily mean that Power of the object will also be zero! But I don't find this in my high school textbook and I can't think of an example on that top of my head where this situation is true. From what I have heard and read, if the velocity of the object is zero then power is also zero. Can someone please clear my supposed misconception or give me an example of the situation where this happens?


I have the list which looks something of this sort. I wanted to know if there is any quick way to create sub list out of this?   list = [1,2,3,4,5,6,7,8,.....]   What is the best way in python to split list into this sublist?   1. [(1, 2), (3, 4), (5, 6), ...] 2. [(1, 2, 3), (4, 5, 6), ...] 3. [(1,2,3,4),(5,6,7,8), ....]


The original question before it was marked as duplicated question:  I was wondering if one construct a non-continuous function $f:X\to Y$ between two topological spaces $X$ and $Y$, such that $f$ sends every convergent net into convergent net... I want to see an example...  Thanks in advance.  Edition:  Can Someone construct a non-continuous function $f:X\to Y$ between two topological spaces $X$ and $Y$, such that $f$ sends every convergent net into convergent net... I want to see an example...  Thanks in advance.  My own Answer:  Consider a two point set $X:=\{x,y\}$ with a topology $\mathcal{T}=\{\emptyset,\{x\},\{x,y\}\}$.  Define $f:X\to X$ by $x\mapsto y$ and $y\mapsto x$.  Then, since $f^{-1}(\{x\})=\{y\}$ where $\{x\}\in\mathcal{T}$, $f$ is not continuous.  On the other hand, pick any convergent net $\{x_\lambda\}_{\lambda\in\Lambda}$ in $X$.  We claim that $f(x_\lambda)$ converges to $y$.  Note that there is only one neighborhood of $y$, $\{x,y\}$, since $\{y\}$ is not open. Then, it follows that $\forall\mu\in\Lambda$, $\mu\prec\lambda\Rightarrow f(x_\lambda)\in\{x,y\}=X$. where $\prec$ is the preorder on the given directed set $\Lambda$.


Do photons experience time and if so how?

I have read that accelerating continuously dilates time in the frame of reference of the traveller asymptotically until reaching speeds near c. You read for example that the voyager could reach the center of the galaxy in just 27 years from his perspective:     But from the reference of a photon traveling at the speed of light, how much time has passed ? And I know those questions are far from graduate level physics but, one paradigm you learn in highschool describes photon as both particule and electromagnetic wave, with a certain frequency. Could you ask then, from the reference of the photon traveling at c, how many time did it oscillate from A to B ?  Does time exists in the reference of the photon or is it traversing the whole space "immediately" in its frame of reference ?    Thanks !


What can I do so the headphone volume is not so loud when I plug it?

I have Logitech H340 headphones with a USB-connector.  When I plug-in the USB-connector, the headphone volume is too loud, even if I set the volume of my Windows 10 PC to one percent (less is impossible, zero percent is no volume).  What can I do so that the headphone volume is not so loud?


my built in camera on my MacBook Pro is not found

All of a sudden my computer is not finding the built in camera... I use this everyday. No FaceTime, no videorecording... nothing.


Resizing in Firefox sometimes removes part of the buttons

When I resize the page (typically on 80% in my case, because I find the text too large to read properly) some layout does not scale well. Incidentally, when I scale it even smaller, the buttons in the image are aligned properly again. Not sure this is a Firefox bug or an SO design bug.


Is there a tool that is similar to the ArcGIS repair geometry tool in QGIS?

I need a tool in QGIS that has the same functionality as the  (native of ArcGIS).


Is there a way to get default currency using apex in single currency org?

I know we can use userinfo.CurrencyIsoCode to get currencycode for user in multi currency org. For single currency org we can manually look into company information and see currency locale.   But is there any way we can use apex to get currency code for single currency org's. I checked both organization and user object if there is any field for default currency but there is no field. Currencytype object is also not enabled in single currency org.    I need to know if there is any other salesforce object from where we can get this information. I don't want to create a custom object where admin can store this information.


Move a specific number of files from a folder to another one (by oldest)

I am currently using this shell to move 25 files to another folder automatically. But It moves files by alphabetical order, that's my main concern. I would like the oldest files to be moved first instead. i=0 for x in *; do   if [ "$i" = 25 ]; then break; fi   mv -- "$x" /my/other/folder/   i=$((i+1)) done  Thanks!


C++ Unresolved external symbol but function is defined

I get this error: LNK2019 unresolved external symbol "public: class std::list<class cg::Component *,class std::allocator<class cg::Component *> > __thiscall cg::GameObject::getComponentsInChildren<class cg::Component>(int)" (??$getComponentsInChildren@VComponent@cg@@@GameObject@cg@@QAE?AV?$list@PAVComponent@cg@@V?$allocator@PAVComponent@cg@@@std@@@std@@H@Z) referenced in function "protected: void __thiscall cg::Scene::fixedUpdate(void)" (?fixedUpdate@Scene@cg@@IAEXXZ)  So the function getComponentsInChildren which is called inside Scene.cpp is not found. Here is the call: #include "Scene.h"  namespace cg {     ...      void Scene::update() {         for (auto i = this->rootObjects->begin(); i != this->rootObjects->end(); i++) {             std::list<Component*> list = (*i)->getComponentsInChildren<Component>(0);   // <--here              for (auto j = list.begin(); j != list.end(); j++)                 (*j)->update();         }     }      void Scene::fixedUpdate() {         for (auto i = this->rootObjects->begin(); i != this->rootObjects->end(); i++) {             std::list<Component*> list = (*i)->getComponentsInChildren<Component>(0);   // <--here              for (auto j = list.begin(); j != list.end(); j++)                 (*j)->fixedUpdate();         }     }      ... }  So I looked inside the GameObject.obj and really there is no symbol containing getComponentInChildren Here is the GameObject h + cpp #include <list>  #include "../Export.h" #include "../Forwarding.h" #include "RTTI.h" #include "Scene.h" #include "Component.h"  #include "../Components/Transform.h"  namespace cg {     class CGAPI GameObject final {     public:         ...          template<typename T>         std::list<T*> getComponentsInChildren(int includeInactive);          ...      private:         ...     }; }  #include "GameObject.h"  namespace cg {     ...      template<typename T>     std::list<T*> GameObject::getComponentsInChildren(int includeInactive) {         if (!RTTI::isComponent<T>())             return nullptr;          std::list<T*> list = getComponents<T>();          for (auto i = this->transform->begin(); i != this->transform->end(); i++) {             if (!includeInactive && !(*i)->getGameObject()->isActiveInHierarchy())                 continue;              list.merge((*i)->getGameObject()->getComponentsInChildren<T>());         }          return list;     }      ... }  I really dont understand why the Compiler does not output the function to the obj? Is there something I miss or is the error somewhere else?


Use implicit differentiation to obtain $\dfrac {dy}{dx}$ .

Use implicit differentiation to obtain $\dfrac {dy}{dx}$. $$x^2+y^2=16$$.  My Attempt: $$x^2+y^2=16$$ Differentiating both sides with respect to $x$, $$\dfrac {d}{dx} x^2 + \dfrac {d}{dx} y^2 = \dfrac {d}{dx} 16$$ $$2x+.....$$


Best bank without incoming wire transfer fees, for receiving money regularly?

I'm going to be receiving monthly wire transfers, and I found out that my bank (US Bank) charges $20 for each one. Are there any good banks that don't charge for incoming wire transfers?


Help building a latch from 1 AND gate and 1 OR gate

I'm having trouble with part of a build I have to do for an alarm system circuit.  The Boolean code is I = M.(A + B + C + D + E). The +s are ORs, . is AND, and I'm using 2-input OR gates and 2-input AND gates.  When M, the master switch, is on, and any of the sensors A,B,C,D or E are triggered, then the alarm will go off i.e. LED lights up.  I need to latch the output signal once the alarm has been triggered and the latched condition should require a cycle of the master switch to reset the alarm i.e. LED stays lit until reset.  I have to do this using 1 OR and 1 AND gate.  I can't use an SR-latch.  All I know is that I need to loop the AND and OR gate to get feedback/memory so the alarm/LED will stay on until reset, at which point reset LED will light up.  Not sure how to do this.  Here's a pic of the circuit I've built so far.    As I said I'm not sure what way to connect the looped AND and OR gate to get the desired result.  I'd really appreciate some help as it's driving me bananas at this point..  ps I got some help on this forum recently as regards latching and since then I've been playing around a lot with the ciruit but I genuinely can't get it to work.


Why can't the Doctor visit a particular point in his timeline to return to Gallifrey (at least temporarily)?

We already know the Doctor never follows the rules of space-time, so why is Gallifrey inaccessible? Shouldn't he be able to, you know, travel to a point in his past when Gallifrey still existed in that universe? We've already seen that the Doctor and his past incarnations can interact without major consequences. Would this create too much of a rip in time? Or has the Doctor just not had the mind to do so?


Help identifying a show I used to watch as a kid

I used to watch a show about a kid (Named Max maybe?) that was given this magic hat that opened portals at specific spots.  He has a fowl friend (a human who evolved into a bird or something) and a giant gladiator friend who was deathly afraid of spiders (or snakes or something).  It was a cartoon, and I can remember the plot of a few of the episodes if needed, I just can't remember the name.


How do I get screen not to mangle some UTF-8 sequences?

I am trying to track down where my UTF-8 is getting mangled, after failing to post emoji into Irssi one too many times. I have managed to get this far:   Local terminal, echo 🔥, displays correctly SSH into my server, echo 🔥, displays correctly Start screen, echo 🔥, pastes as question-mark-in-diamond thing, hit Enter, displays the same question-mark-in-diamond thing.   Since it happens on pasting, maybe the issue is happening getting the data to the server, as opposed to getting it from the server...  Locale on the local terminal (macOS 10.12.1 Terminal.app):  LANG="en_AU.UTF-8" LC_COLLATE="en_AU.UTF-8" LC_CTYPE="en_AU.UTF-8" LC_MESSAGES="en_AU.UTF-8" LC_MONETARY="en_AU.UTF-8" LC_NUMERIC="en_AU.UTF-8" LC_TIME="en_AU.UTF-8" LC_ALL=   Locale on the server (Ubuntu 14.04.1 LTS):  LANG=en_AU.UTF-8 LANGUAGE= LC_CTYPE="en_AU.UTF-8" LC_NUMERIC="en_AU.UTF-8" LC_TIME="en_AU.UTF-8" LC_COLLATE="en_AU.UTF-8" LC_MONETARY="en_AU.UTF-8" LC_MESSAGES="en_AU.UTF-8" LC_PAPER="en_AU.UTF-8" LC_NAME="en_AU.UTF-8" LC_ADDRESS="en_AU.UTF-8" LC_TELEPHONE="en_AU.UTF-8" LC_MEASUREMENT="en_AU.UTF-8" LC_IDENTIFICATION="en_AU.UTF-8" LC_ALL=   Additional diagnostics:   screen -U doesn't change things :utf8 on command from inside screen acknowledges that it has turned on UTF-8 support, but doesn't change things echo 火 does print 火 as expected, so it's not like all UTF-8 text is broken.


Align bibliography from biblatex with leftmargin section headings from titlesec

I want to align the bibliography produced by biblatex's \printbibliography with a leftmargin section (as defined by the titlesec package).  Even if I change \topsep and \partopsep to negative values via \defbibenvironment, I cannot get the bibliography to align with the section heading.  This is the result I get:    How can I make the first publication start in line with the "Publications" heading, just like "Dolor sit amet" is in line with "Lorem ipsum"?  \begin{filecontents*}{\jobname.bib} @article{author2019,   author = {Author, Anne},   date = {2019},   title = {A Title},   journaltitle = {Fancy Journal},   volume = {1},   number = {1},   pages = {350--370} } @article{author2020,   author = {Author, Anne},   date = {2020},   title = {A Title},   journaltitle = {Fancy Journal},   volume = {1},   number = {1},   pages = {350--370} } \end{filecontents*}  \documentclass[11pt]{article}  \usepackage[   top=0.25in,   bottom=0.25in,   right=0.25in,   left=1.375in]{geometry}  \usepackage{parskip}  \setcounter{secnumdepth}{0}  \usepackage{titlesec}  \titleformat{\section}[leftmargin]   {\Large\scshape\raggedright}   {\thesection}   {1em}   {}  \titlespacing{\section}   {8pc}   {1ex plus .1ex minus .2ex}   {0pc}  \usepackage[american]{babel} \usepackage{csquotes} \usepackage[   backend=biber,   style=authoryear]{biblatex}  \addbibresource{\jobname.bib}  \defbibenvironment{bibliography}   {\list{}     {\setlength{\leftmargin}{\bibhang}%      \setlength{\itemindent}{-\leftmargin}%      \setlength{\itemsep}{\bibitemsep}%      % Setting these two negative values decreases the spacing somewhat, but not enough      \setlength{\partopsep}{-30pt}%      \setlength{\topsep}{-30pt}%      \setlength{\parsep}{\bibparsep}}} {\endlist} {\item}  \begin{document}  \section{Lorem ipsum}  Dolor sit amet, consectetur adipiscing elit. Mauris quis ligula arcu.  \section{Publications} \nocite{*} \printbibliography[heading=none]  \end{document}


In Bash, when to alias, when to script, and when to write a function?

It's taken me almost 10 years of Linux usage to ask this question. It was all trial and error and random late-night internet surfing.  But people shouldn't need 10 years for this. If I were just starting out with Linux, I'd want to know: When to alias, when to script, and when to write a function?  Where aliases are concerned, I use aliases for very simple operations that don't take arguments.   alias houston='cd /home/username/.scripts/'   That seems obvious. But some people do this:  alias command="bash bashscriptname"   (and add it to the .bashrc file)   Is there a good reason to do that? I'm trying really hard, but I genuinely can't think of any circumstances in which I'd want to do that. So, if there is an edge case where that would make a difference, please answer below.  Because that's where I would just put something in my PATH and chmod +x it, which is another thing that came after years of Linux trial-and-error.  Which brings me to the next topic. For instance, I added a hidden folder (.scripts/) in the home directory to my PATH by just adding a line to my .bashrc (PATH=$PATH:/home/username/.scripts/), so anything executable in there automagically autocompletes.  If I needed to.  I don't really need that, though, do I? I would only use that for languages that are not the shell, like Python.  If it's the shell, I can just write a function inside the very same .bashrc:  funcname () {   somecommand -someARGS "$@" }   As I stated, I found a lot of this out through trial and error. And I only truly saw the beauty of functions when my computer died and I was forced to use the computers of the people around me when they weren't using them.   Instead of moving a whole directory of scripts from computer to computer, I ended up just replacing everyone else's .bashrc with my own, since they had never even made a single modification.  But did I miss anything?   So, what would you tell a beginning Linux user about when to alias, when to script, and when to write a function?   If it's not obvious, I'm assuming the people who answer this will make use of all three options. If you only use aliases, or only use scripts, or only use functions—or if you only use aliases and scripts or aliases and functions or scripts and functions—this question isn't really aimed at you.


Let $A$ be a integral domain, $b\in A$ a nonzero element and $S=\{b^n\mid n \in \mathbb{N}\cup\{0\}\}$ Prove: $S^{-1}A \cong A[x]/(bX-1)$ For this we define the homomorphism $\varphi: X\longrightarrow1/b$ and prove that $\ker\varphi=(bX-1)$ Since $\varphi(bX-1)=b·1/b-1=0$ we have that $\ker\varphi \supseteq(bX-1)$ Now we have to see that any $f\in \ker\varphi$ is in the ideal $(bX-1)$, the obvious way to approach this is to divide $f$ by $bX-1$, but we can't apply the division algorithm directly since the main coefficient of $bX-1$ is not necessarily $1$. Any help to prove $\ker\varphi \subseteq(bX-1)$?


Proving size of a collection of ordered pairs of disjoint subsets using bijection

I've been having a lot of trouble with this problem.     Let $n \ge 0$ be an integer and let $S_0$ be the collection of ordered pairs of disjoint subsets of $\{1, . . . , n\} = [n]$; that is,   $$ S_0 = \{(A, B) : A \subseteq [n], B \subseteq [n], A \cap B = \emptyset\}. $$      Show using a bijection that $|S_0| = 3^n$.


I have an rsyslog server running Ubuntu 12.04 which stores logs from different clients also running Ubuntu 12.04. Now I want to view those logs from my machine which also runs Ubuntu 12.04.  One way is to ssh to the server and view the logs using tail etc. but that's very tiring and not possible at all so isn't there any good opensource tool I can use to access those logs on my machine from the server it will be convenient if its a GUI application or a browser based one. Thanks.


How to enable permission to access USER folder on external hdd (windows 10)

My computer crashed but the HDD is intact. I have been able to browse that hard drive from another Windows computer, except for the Users folder where I get the message:     "You dont currently have permission to access this folder" [continue] [cancel].    Also, I do not get access denied msg.  When I click continue it just hangs.


about isomorphic between polynomial ring

let $k$ be algebraic close field , why following rings are isomorphic ? $k[x, y] /\left(y-x^{2}\right) \cong k\left[x, x^{2}\right] \cong k[x]$ i need theorem for general case for example when $k[x, y] /\left(f(x,y)\right)  \cong k[x]$ ? for what $f(x,y)$ this is true ?


why am i getting java.lang.NullPointerException when my list is not null?

everything in my code works fine till I get to the end and want to sort the list. the driver and the method both compile fine and the arraylist is present since it is used for all the other methods in the driver but when I go to sort the list I get an error.   this is the end section of the driver          intList.removeAt(position);                                 //Line 31     System.out.println("Line 32: After removing the "                       + "element at position "                       + position                       + ", intList:");                          //Line 32      intList.print();                                            //Line 33     System.out.println();                                       //Line 34      System.out.print("Line 35: Enter the search "                     +  "item: ");                               //Line 35     System.out.flush();                                         //Line 36      num.setNum(Integer.parseInt(keyboard.readLine()));               System.out.println();                                             if(intList.seqSearch(num) != -1)                                    System.out.println("Line 40: Item found in "                         + "the list");                               else                                                                System.out.println("Line 42: Item not found");                 System.out.print("List 43: The list temp: ");                    intList.sortList();                                  //line 91 (problem line)            System.out.println();   } }   here is the method:  public class OrderedArrayList extends UnorderedArrayList {  public OrderedArrayList(int size) {       super(size); }  public OrderedArrayList() {     super(); }      //Copy constructor public OrderedArrayList(OrderedArrayList otherList) {     super(otherList);  }   public void sortList()  {// start sort  list.print();   int min, i, j;    DataElement temp;    for (  i = 0; i < list.length; i++)     {// start for     // Assume first element is min     min = i;     for (  j = i + 1; j < list.length; j++)      {                                        // line 30 (other problem line)         if (list[j].compareTo (list[min])<0)          {             min = j;          }      }     if (min != i)      {         temp = list[i];         list[i] = list[min];         list[min] = temp;      }     System.out.println(list[i]);      }    }// end sort  }   and this is my output including the error:   ----jGRASP exec: java -ea Example3_1 Line 7: Processing the integer list Line 8: Enter 8 integers on the same line: 1 5 8 7 4 6 9 2  Line 16: The list you entered is: 1 5 8 7 4 6 9 2   Line 19: Enter the num to be deleted: 1  Line 24: After removing 1 the list is: 5 8 7 4 6 9 2   Line 27: Enter the position of the num to be deleted: 1  Line 32: After removing the element at position 1, intList: 5 7 4 6 9 2   Line 35: Enter the search item: 5  Line 40: Item found in the list List 43: The list temp: Exception in thread "main" java.lang.NullPointerException at OrderedArrayList.sortList(OrderedArrayList.java:30) at Example3_1.main(Example3_1.java:91)  ----jGRASP wedge2: exit code for process is 1. ----jGRASP: operation complete.


Can You Stop the Migration Assistant Midway Through?

Can the Migration Assistant be stopped midway through? I began the wireless transfer from a Mac Mini to a new MacBook Air last night. It still says it's going to take 40 hours. Unfortunately, I can't wait that long, and the process is taking up both of my computers.   In case of catastrophic failure what recourse do I have, as the MacBook Air doesn't have a system restore disk?


Upgraded to 13.10 now clock settings are all disabled and clock does not display

I've upgraded to 13.10 and now I don't have the standard menu clock, which I need for work.  I checked and 'indicator-datetime' is installed.  I even uninstalled/reinstalled that applet with no luck.  Also my "clock" settings under System Preferences are all disabled.  I can't change anything.  Does anyone know how I can get the old menu clock back?  Alternatively is there another menu clock app I can download?  Edit 1  Thanks for the responses    I've restarted several times and that didn't fix the issue. I just ran the 13.10 update today.  But I ran it again a few minutes ago.  I got   about 200KB in random updates.  The issue is still present after a reboot. # apt-cache policy indicator-datetime indicator-datetime: Installed: 13.10.0+13.10.20131016.2-0ubuntu1 Candidate: 13.10.0+13.10.20131016.2-0ubuntu1 Version table: *** 13.10.0+13.10.20131016.2-0ubuntu1 0     500 http://us.archive.ubuntu.com/ubuntu/ saucy/main amd64 Packages     100 /var/lib/dpkg/status   Edit 2  I believe the issue is related to 'rarings' changing the systray somehow...   Or , although I haven't got that solution to work yet.  Edit 3  Because of a suggestion from RolandiXor I've check the binaries.  My system is missing 'libical.so.0' but it has 'libical.so.1'.    ldd /usr/lib/x86_64-linux-gnu/indicator-datetime-service libical.so.0 => not found   Does anyone know how to get the libical.so.0 binary that the datetime service needs but doesn't install?


When an application crash without output an error, is there a log that i can check?

Sometimes it happen that some application crash without give no output error (conky in my case, probably is one of my configuration that is incorrect).  Is there somewhere a error log that I can check to understand why it is crashed?


How to generate a CSR for attaching SSL certificate to the site?

How can I generate a CSR for attaching SSL certificate to the site? In various articles about installing SSL certificates are described different ways of generating private key and CSR. That's like two different versions: (a) openssl req -nodes -newkey rsa: 2048 -keyout myserver.key -out server.csr and (b) openssl genrsa -des3 -out www.mydomain.com.key 2048.  So -   How to generate a CSR and private key? What is the difference between the teams generate CSR and key (a) and (b)? Do I need to set a password when generating the CSR and key? Reduces whether a site is vulnerable to attack as the password for the private key?


I know that there's a "Missing" command in the Chat Wheel that will report your lane missing, but that only does "Missing Top!" or "Missing Middle!" messages it seems. I've seen people call specific heroes missing before though:     How are they doing this? Is it some kind of hotkey I haven't found? Is it some complicated custom bind? Is it just something simple that I'm missing?


Does the PS4's manufacturer warranty cover international purchases?

I want to buy a PS4 from the USA for use in India, but I'm worried that if something goes wrong that I won't be covered by warranty.   Does Sony's manufacturer warranty cover for the complete product, i.e. is it an international warranty from Sony?  Furthermore, will a USA console work in India?


Particle System (Hair) - Rendered objects appears rotated/ off place

I was working on creating a grass plane and during the process of creating it, I made a plane on which the particle system was to be applied and an object - grass blade which is to be dispersed on the plane. I created a small number of varied grass blades and joined them. Upon choosing the group of grass blades ad the hair emission object of the plane, the result appears to be: the grass blades spawn half on one side and the other half on the other side (shown in the picture) and the grass blades sometimes seem to lay horizontally on the plane rather than vertically. The grass blades also overflow the borders of the plane as shown in the picture. best, Jassim


Using the xr package in LyX (for cross-referencing an external LyX document)

Question: What steps are required to use the xr package in LyX in order to reference items in other, independent LyX documents?  Steps already taken:   The tools package (that contains the xr package) has been installed in MikTeX. The xr package has been used in the referencing document (by adding \usepackage{xr} to the referencing document's preamble). A pointer to the referenced document has been set in the referencing document (by adding \externaldocument{referenced.lyx} to the referencing document's preamble). A label in the referenced document has been cross-referenced in the the referencing document using the \ref tag.   Observed (undesired) behavior: The reference appears as "BROKEN" in the LyX editor. The PDF output shows "??" where the reference number is expected.  Relevant links:       Software used: LyX + MiKTeX + BibTeX on Windows 7  My level of Lyx/LaTeX proficiency: Beginner+


I've started learning sequences and I'm having a hard time calculating the following:  $$\lim_{n\to ∞}{\sqrt[n]{3^n + 7^n}}$$  Using Heine’s Lemma I'm trying to solve it analogous to the corresponding limit definitions for functions, but I get stuck every direction I go.  Any help is appreciated.


How to get one of those nifty images that shows your avatar, reputation and badges?

Today, while browsing for a question, I encountered this wild Pokemon. I saw it in his profile and I do not know how the user created that.    So my question is, how can I make something like that? If you can provide the necessary steps to take, that would be appreciated.


Screen brightness reset to minimum after every reboot on HP Pavilon DV4. HELP

Ubuntu 13.10 doesn't save my brightness settings between sessions. Everytime I boot up, the brightness is always at zero, and I always have to set it back to my preferred setting (at maximum). How can I ensure that my brightness preference will persist after reboot? I am using a HP pavilion dv4. I see where this question has been answered but no one gives step by step instructions on how to get it completed. Thank you


How to change tag tooltip to tag Description?  I tried and my code is mentioned below.  function title_text( $description ) {     return sprintf( _n('%s topic', '%s', $description), $description ); }  wp_tag_cloud( array( 'topic_count_text_callback' => 'title_text') );   This is not working. Can any one please check this code and find me a correct solution?


What firewall ports do I need to open when using FTPS?

I need to access an FTPS server (vsftpd) on a vendor's site. The vendor has a firewall in front of the ftps server. I have a firewall in front of my FTPS client.   I understand that ports 990, 991 and maybe 989 need to be opened up for control traffic.  I have some questions:   When looking at it from the vendor's firewall perspective, should these ports be opened up for both inbound and outbound traffic?  What about ports for the DATA channel? Do I have to open all ports above 1000? Should I do it for both inbound and outbound traffic ?


Hi all I have an h2 element like so:
Back
   and I added an image before:  #back::before {     background-image: url(/images/arrow.png);     background-size: 20px 30px;     display: inline-block;     width: 30px;     height: 40px;     content: "";     background-repeat: no-repeat;     background-position: center; }   However the output is the screenshot attached...my question is how do I get my arrow to be aligned in the middle and before the text. How would I do that?


Ramifications of a world of unrestrained truth

Are there any papers/books/studies on the ramifications of a theoretical world of unrestrained truth, meaning no secrets? A part of the motivation for this question is the fictional show, Code Geass, where a character has the aim of utilizing supernatural forces to rebuild the world with lacking in secrets. It got me thinking about what such a world would actually be like, but I'm having a hard time comprehending it. Similarly, are there any sources that study the necessity of secrets in our existing world? For example: States (defined as entities that have a monopoly of violence over a certain area and group of people) have secrets which are necessary for their continued existence and security, corporations have trade secrets, and of course individuals have secrets.    Some speculation is available at the following thread but no specific sources were given:


Get and Set Hide in viewport and Disable in viewport via Python API

In my plugin I have an operator that needs to iterate through potentially 100's of objects that might be 'hidden in viewport' or 'disabled in viewport' and perform some operations  that require the object to be visible in viewport. Afterwards I want to restore whatever visibility the object had, so I need to both get and set these options.  IE, get/set the status of these. When I hover over the icons, both show the parameter bpy.context.object.hide_viewport. Obviously they can't both be the same parameter as they both do different things. How do I get and set 'hidden in viewport' and how do I get and set 'disabled in viewport' using the Python API? Edit: I can see that both ObjectBase(bpy_struct) and Object(ID) have the hide_viewport property, however ObjectBase is documented as 'Temporarily hide in viewport' and Object is documented as 'Globally disable in viewports'. How do I access an Object's ObjectBase?


Let $\mathcal{S}$ be a non-empty bounded set of real numbers, and define for a real number $a$ the set $aS=\left\{ax|\ \ x \in\mathcal{S}\right\}$. Prove that $\sup(aS)=a \inf S$ and $\inf(aS)=a \sup S$ if $a<0$.


Attaching files and not wanting them embedded into email body

Company Director with a MacBook Air and she's having problems attaching pages files and PDF's to her e-mails. Mail keep embedding them into the message window so she cannot type, or see what she's typed in the window. Many times recipients of her messages say they are missing some of the attachments she thinks she has attached.  How can I turn off the embedding of any attachments into the message body and just displaying them as a 'file' icon somewhere rather than the contents?


In single-blind peer-review, can you reveal your identity without the editor's consent?

In my field (chemistry), review is always done in a single blind process, i.e. the author does not know who the referees were, but the referees do know who the authors are. In ten years, I have never seen a referee breaching this anonymity, e.g. by signing their review, unless they got prior approval by the editor (in order to continue discuss things further with the authors, once the manuscript was accepted for publication).  So, it seemed logical to assume that in single blind peer-review, the reviewer should not disclose his identity without the editor's consent. Yet, some people have told me ( and ; also IRL a friend from human sciences) that they have seen people sign their reviews, or write emails to them after the review but before the paper is published.  So, in single-blind peer-review, can you reveal your identity without the editor's consent? Does it depends on the customs of each field, or is there a hard rule? (in which case, the few anecdotes I heard were outliers)


beamer does not honour \setmainfont, how to fix?

I have a local set of .ttf files which I'd like to use in my presentation.  When I create an article document the font gets selected properly:      \documentclass[12pt,a4paper]{article}      \usepackage{fontspec}     \setmainfont [ Path = fonts/open-sans/,          Extension      = .ttf,         UprightFont = *-Regular,         BoldFont = *-Semibold,         BoldItalicFont = *-SemiboldItalic,         ItalicFont = *-Italic     ] {OpenSans}      \usepackage{blindtext}      \begin{document}             1234567890              \blindtext     \end{document}   But when I change this to a beamer presentation I end up with a different font:      \documentclass{beamer}      \usepackage{fontspec}     \setmainfont [ Path = fonts/open-sans/,          Extension      = .ttf,         UprightFont = *-Regular,         BoldFont = *-Semibold,         BoldItalicFont = *-SemiboldItalic,         ItalicFont = *-Italic     ] {OpenSans}      \usepackage{blindtext}      \begin{document}         \begin{frame}             1234567890              \blindtext         \end{frame}     \end{document}   Here you see the difference:      The lower text is the right font in article mode, the upper one the beamer standard.  I even tried to use \setbeamerfont but this didn't change anything.  Can somebody please point me how to convince the beamer class to use the provided font files?  This is my environment:  $ lualatex --version This is LuaTeX, Version beta-0.80.0 (TeX Live 2015/Debian) (rev 5238)  $lualatex testfonds-article.tex | grep "Document Class: beamer" Document Class: beamer 2015/01/05 3.36 A class for typesetting presentations (rc


Let $p$ a cut point of a connected space $(X, \mathcal{T})$ and suppose $C$ and $D$ form a separation  of $X-\{p\}$, i.e $$X-\{p\}=C \cup D$$ Prove that $C \cup \{p\}$ is conected. I have this idea: Since $p$ is a cut point then $X-\{ p \}$ is not connected, and since $C$ and $D$ form a separation of $X- \{p \}$ then $X-\{p \} = C \cup D$, and also $C \cup D$ is not connected. And also $$C \cap \overline{D}= \overline{C} \cap D= \emptyset$$ I need an idea to continue please


How to decline a specific day but accept all others in a recurring Outlook meeting?

I attend daily standups with one of our development teams.  On Thursdays, I have a conflict but can attend all other days.  Is there a way to decline all Thursdays going forward, while accepting any other day?    Currently, I decline each Thursday individually, which isn't ideal.  Did a pretty extensive search and found plenty of answers around declining all meetings after specific dates, but nothing on this specific use case. But I'm sure I'm not the only one with this scenario!  I use outlook on both PC and Mac, if that affects the answer.


What does `yield return false` do in Unity C# scripts?

Regarding the duplicate:  I got an answer for this over at GameDev.SE. It's pretty clear that this is not a duplicate, though it is now asked on both sites.      We have this code:  private IEnumerator SomeFunction(/*lots of arguments*/) {     // Wait until the local dictionary is loaded     while (!BundleLibrary.Instance.LocalBundleDictionaryLoaded)     {         yield return null;     }      //Wait for remote dictionary loaded if needed     if (BundleConfig.Instance.WaitForRemoteDictionary)     {         while (!BundleLibrary.Instance.RemoteBundleDictionaryDownloaded)         {             yield return false;         }     }     // more code below here }   I get that yield return null means the routine will pick up where it left off on the next frame.  But I don't really understand what the yield return false does. I haven't seen it, but I wouldn't know what yield return true would do, either.


Is there a penalty for death in Dragon Age Inquisition?

The title should be self-explanatory. If you die in Dragon Age Inquisition, as in all party members die, do you loose anything? Experience, gold, gear, etc?


Show that $x^n + x + 3$ is irreducible for all $n \geq 2.$

So first of all, I used the following from my lecture notes:   If $f \in \mathbb{Z}[x]$ is primitive (gcd of all the coefficients is 1) - $f$ irreducible in $\mathbb{Z}[x] \Leftrightarrow$ f irreducible in $\mathbb{Q}[x]$.   So now I only have to show that $f_n = x^n + x + 3$ is irreducible in $\mathbb{Z}[x]$ for all $n \geq 2. $  Is there a pattern I should be appealing to in some way?


I have to make the list look exactly like this (Cyrillic letters are not the problem). Could you please help me.


How do I find all tables in a DB that have no explicit primary key?

A Google search spewed forth millions of hits on how to find tables without clustered indexed, the PK normally being the clustered index of a table. However, a table could easily have a natural key as a clustered index, and a non-clustered surrogate index, like an identity column.  How do I find all tables in a DB without a primary key defined? I have 245 tables in this DB: manual inspection is grossly inefficient.


Can a ring without unity have a non-trivial subring with unity?

The original problem was to prove that for any commutative ring R, there is a canonical (unique) ring homomorphism from Z to R. The problem would be simple, if R has $1_R$ and we can let the homomorphism map $\phi$ sends $0$ to $0_R$ and $1$ to $1_R$. But if R doesn't have an identity, and $\phi(Z)$ forms a subring of $R$ with unity $\phi(1)$, then the Rng $R$ has a subring with unity. If ring without unity can only have a trivial subring with unity, $\phi$ must be the trivial map, and the proof would be complete. But I'm not sure of this part. Any help would be appreciated!


What are the bad reasons for downvoting?

I had  a  some time back... and there was another better answer for that question, but mine got accepted and initially there were  some upvotes for it...  But sometime later it started getting more attention and started getting more downvotes mostly because it was a poor answer and the other one was better... but the interesting portion was most of the downvotes was not for the answer, but to give more visibility to the another answer....  Is it justified?  Note: I will be taking down my answer after some time because the other one is better.


Scientists have found very bright source of light which they call  and the are found to be . So these black holes are so massive that they cannot be formed by a supernova. So how are these formed?


Where should I specify pdftex primitives?

I would like to suppress this type of warning by pdftex:     PDF inclusion: multiple PDFs with page group   So one solution proposed  is to use this primitive:  \pdfsuppresswarningpagegroup=1   Where should I specify it? In the premable of the .tex document? Or elsewhere?