Add two comment lines to the top of a file

I am trying to have a sed script that makes changes and outputs a new file, but it must add two comment lines to the top, so that the output file can then be itself run as a bash script. The trouble is that all the solutions I have seen for adding two top lines do not apply to comments, which render the script itself non-functioning. So for example if my sed results in a file like this: AAAA BBBB CCCC DDDD  I want to end up with something looking like this: #$ -cwd #$ -pe mpi 16  AAAA BBBB CCCC DDDD  I have already tried variations on things like this: sed -i '1s/^/#$ -cwd\n/' output.txt  But these will treat everything past the # as comment. How can I write a bash script that will add the comment headers without messing itself up? Thanks!


rendered image looks distorted or blurry

When I rendered the animation as images, the images produced looked somehow distorted or blurry. Can anyone help me to fix this?


Is there any way to change the installed version of AppleScript?  After mistakenly identifying my version of AppleScript as 1.0 by using a  (turns out that just checks the version of the script you are currently running, which is implicitly 1.0) and trying to figure out how to upgrade, I was wondering how/if it's possible to change the installed version of AppleScript?


What is the parenthetical plural of "baby"?

A letter home from daycare may be sensitive to the fact that some children have a single parent like this:     Dear Parent(s),   And if that same letter home wanted to be sensitive to the fact that I may have more than one child enrolled:     This letter is concerning your child(ren)...   But what if I have twin infants? (twinfants)     This letter is about your baby(ies)...   I believe the parentheses indicate that the letters within are optional, but do they also indicate that you should remove the y?  EDIT: The suggested duplicate has many suggestions, none of which is backed by a guideline or rule. Is there no rule governing this behavior?


Relative paths based on file location instead of current working directory

Given:  some.txt dir  |-cat.sh   With cat.sh having the content:  cat ../some.txt   Then running ./cat.sh inside dir works fine while running ./dir/cat.sh on the same level as dir does not. I expect this to be due to the different working directories. Is there an easy way to make the path ../some.txt relative to the location of cat.sh?


ttf-mscorefonts-installer fails to update. Unistall/ install

I am sure, this is going to be a duplicate thread, but believe me, I tried out all the original ones In fact. Whenever my system starts up, I am welcomed with this message below:    I searched all the forums, reinstalled, restarted, uninstalled an installed again, rebooted, completely removed including folder and cache. Tried everything that' literally found in the forms, I tried rebooting after I done all these works arounds. Yet no hope, this annoying thing pops up and makes my day worse. Any help largely appreciated. Almost 20+ solutions I tried one after another btw.


How many integer solutions are there to the inequality $x_1 + x_2 + x_3 \leq 17$ if we require that $x_1 \geq 1$, $x_2 \geq 2$, $x_3 \geq 3$?

How many integer solutions are there to the inequality $x_1 + x_2 + x_3 \leq 17$, if we require that $x_1 \geq 1$, $x_2 \geq 2$, $x_3 \geq 3$?  The way I did it:  $x_4 = 17-x_1-x_2-x_3-x_4$  $x_1+x_2+x_3+x_4 = 17$  $x_1= x_i + 1$  $x_2= x_{ii}+2$  $x_3= x_{iii}+3$  $x_4= x_{iiii}$  So,  $x_i+1+x_{ii}+2+x_{iii}+3+x_{iiii}= 17$  $x_i+x_{ii}+x_{iii}+x_{iiii}=11$  $3$ bars, $\binom{14}{3} =364$ different ways? Is this the right approach? correct answer?


Can I run Fallout : New Vegas without a video card?

I was looking at my laptop's specifications ( an Hp probook ) and it doesn't have a video card. Can I still get and run Fallout : New Vegas? Not the ultimate edition.


Feature Request: Answer a question later

I've skipped many questions that I can answer because of lack of time. And later, I can't find those questions.  It would be helpful if there were an Answer Later feature as an option. Inside my profile would be a section with those questions visible only for me.


So, the plausible explanation to who put the wormhole and the tesseract in the place is   Humanity survived through the plan B, that's why they mention it all the time. Then they build the worm hole to save the people of the planet.  But this explanation raises another question and yet another (similar) paradox. Question -   Why didn't they just simply give us the information from black hole that we need figuring out how to manipulate gravity?  Paradox -   Not to mention that why on Earth would the future descendants (by a margin of more than 1,000,000 years) care to change their timeline in order to save the long dead inhabitants of Earth by eradicating themselves from existence in the process? This is more than a logical question, this is a Mad Scientist Paradox.  References & Sources:   ,  (on reddit).


Post hoc test after ANOVA with repeated measures using R

I have performed a repeated measures ANOVA in R, as follows:  aov_velocity = aov(Velocity ~ Material + Error(Subject/(Material)), data=scrd) summary(aov_velocity)    What syntax in R can be used to perform a post hoc test after an ANOVA with repeated measures? Would Tukey's test with Bonferroni correction be appropriate? If so, how could this be done in R?


Please don't use comments containing vulgarities for suggested edit review audits

I come across this comment while reviewing :     I don't think system-generated messages should contain such language. Can they be chosen more carefully, please?


Problem seeing Macintosh HD under Boot Camp

I can't see the Macintosh HD partition under Windows 10 in Boot Camp. I've already followed some guides on how to solve this problem that talk about CoreStorage etc...  Now when I get this:  sudo diskutil cs list No CoreStorage logical volume groups found   I still can't see the drive from Windows, what should I do?   My Mac is a 13" Mid-2012  macOS Sierra 10.12.3 Windows 10


prove a general inequality between radicals

I've been trying to work on a proof for this for a few days now, but can't seem to see the answer. It might be trivial but I would be grateful if anyone could let me know their strategy (if not a proof) for this:  $$\sqrt[n]{n!} \lt \sqrt[n+1]{(n+1)!}$$  Thanks in advance!


Taking break/vacation during graduate studies/PhD

Do people take time out to go home, meet with family etc. during their PhD?   If yes then for how long and how frequently is it usually?   How does one deal with this with one's advisor?  What are the pros and cons?     Given that one basically has just about 2-3 years in practice to do all their PhD work, I don't understand how anything else fits in the schedule except work. The entire idea of a PhD looks quite scary to me that one is expected to produce cutting-edge stuff in that short a time starting from just standard graduate courses!    PS: the question is general, but if it is field-dependent, I am interested in particular in physics PhDs (theoretical high-energy physics specifically)


MacOS terminal switches computer name from “macbook-pro” to “huawei_p_smart”: should I worry?

When opening a terminal, I noticed that the laptop's name displayed in front of the username changed from something like "myname's_MacBookPro" to "huawei_p_smart-XXX". Why did this change happen, and should I worry about this? I do not own a Huawei, nor did I change any of my laptop's settings myself. I'm running iTerm on MacOS Catalina v10.15.7. Screenshot:


If A and B are both diagonalizable, is AB also diagonalizable?

Here are my steps:  $PAP^{-1}PBP^{-1}=PABP^{-1}=AB$, since both are diaglonalizale, the equation is established, is it correct?


Prove $ \lim_{n\to\infty}\sqrt[n]{p(n)}=1 $ for polynomial

Let $ p(x)=\sum\limits_{k=0}^{d}a_kx^k $ polynomial such that $  \forall x>0, p(x)>0 $     Prove that:   $$ \lim_{n\to\infty}\sqrt[n]{p(n)}=1 $$


Where can I download 64 bit geoprocessing for ArcGIS 10.3?

Where can I download the 64 bit geoprocessing for ArcGIS 10.3?  I know it can be done from the instalation CD, but I don't have access to it at my work.  Do I just have to install ?


Change icons for a specific file type in Ubuntu 18.04

I want to change the icons for a specific file type (*.py to be specific) on Ubuntu 18.04.  What's the simplest way to do it?  I'm using Ubuntu-mono-Dark as the icon theme.


Will deceleration in a geostationary orbit kick me into a higher orbit?

Lets say I am in a spaceship, and I throw a piece of space trash out the back of the spacecraft in the opposite direction from my direction of motion. The mass of the trash is small enough that it doesn't effect the orbit of my spaceship. What will happen? Will the space trash go into a higher orbit from the deceleration? or will it just  continue to orbit behind me at a slower rate?


How did Planck derive his formula $E=hf$?

Some time ago I asked my quantum physics lecturer the question:     How did Planck derive his formula, the    $$E=hf$$    with constant of proportionality $h$, the .   I was motivated by the fact that every lecturer talks about the history of this formula (black body, birth of quantum mechanics etc) but I've never encountered an explanation of how Planck derived it.   My lecturer told me that he had researched it and found only old articles in German. Moreover he said that he couldn't find a derivation in professional physics books. This is something that every author assumes needs no derivation.  So how did Planck derive this formula?


Find the eigenvalues of a matrix with ones in the diagonal, and all the other elements equal

Let $A$ be a real $n\times n$ matrix, with ones in the diagonal, and all of the other elements equal to $r$ with $0<r<1$.    How can I prove that the eigenvalues of $A$ are $1+(n-1)r$ and $1-r$,  with multiplicity $n-1$?


Is the money you get from shorting a stock free to use for going long on other stocks?

I shorted a particular stock which resulted in $10,000 being deposited into my Interactive Brokers account. I then put all of that $10,000 into VTI (total stock market index). Basically making the bet that the stock I shorted will perform worse than the total stock market.   I assumed I would be charged some sort of interest or fees for using that money, however it appears that I am not being charged at all. Are there really no costs for doing this?


I've heard people saying "I am going to town", why can't it be "I am going to the town"?  And why is it "I go to the city" and not "I go to city"?


Windows10 is missing in boot menu Ubuntu 18.04

During apt-get update of Ubuntu 18.04 the Windows10 is missing. How to get back back the Windows10?


Grub2 to see new Windows 10 loader instead of Windows 8 loader

I was running a dual-boot of Ubuntu 14.04 and Windows 8 Pro. I recently took advantage of the free Windows upgrade and upgraded my Windows 8 to 10, however; whenever I start up my machine, Grub2 still lists my Windows loader as Windows 8 and whenever I select Windows I get the old Windows 8 logging on screen for a while before getting into Windows 10. Am new to Ubuntu so I don't know if this is a Grub2 problem or something else. Please help


Does using the skull jack on enemies in x-com 2 give research bonuses?

I know that in x-com stunning and interrogating an enemy would give you a boost to research.    Currently while playing x-com 2, my weapon research is slow, but I'm yet to find a way to speed it up.  Do the same ideas apply that I need to find the right alien type to skulljack to gain a research bonus?


public static String checkStatus(String status)     {         while((status != "s" || status != "S" || status != "m" || status !=    //this line is in the main program marital = checkStatus(marital);  //this is a method that keep asking for s or m if user input is not s or m public static String checkStatus(String status)  {   while(status != "s" || status != "S" || status != "m" || status != "M")   {    status = JOptionPane.showInputDialog(null, "Please enter M or S for marital status: ");    }   return status;  }     "M"))         {             status = JOptionPane.showInputDialog(null, "Please enter M or S for marital status: ");      }     return status; }   //I keep getting a infinite loop that ask for m or s


Why doesn't the official StackExchange android app support chat?

Why doesnt the official SE android app support chat . It would be better to have an all in one app that wouldn't require us to rely on third party softwares or browsers. I came across a third party app that supports chat :   Personally ,i dont prefer using browsers on a mobile given that they aren't smooth enough compared to what a chat app would be like.


If $a,b\geq 0$ show that $\left| \sqrt{a}-\sqrt{b}\right|\leq\sqrt{\left|a-b\right|}$.  WLOG we can assume that $a\geq b$. If one of them is $0$ this is trivial. So assume none of them is $0$. Now, $$\left| \sqrt{a}-\sqrt{b}\right|\leq\sqrt{\left|a-b\right|} \iff a-2\sqrt{ab}+b\leq a-b \iff -2\sqrt{ab}\leq -2b \iff \sqrt{ab}\geq b \iff ab\geq b^2\iff a\geq b$$  Is this proof correct?


Polygon Neighbors not found in Proximity Toolset of ArcGIS Desktop 10.0?

I cannot find the Polygon Neighbors tool. I have searched for it as I usually do and I have also browsed the proximity toolset but it is not there. The other Tools, e.g. Buffer and Near are there and work fine. Here is a screenshot:


How do you lengthen the amount of time that Time Machine keeps hourly backups?

Time Machine keeps hourly backups for 24 hours by default before purging for daily backups and I'd like to extend this further (to a week of hourly backups). Is there a way to change the backup retention policy config to allow for this? There doesn't seem to be an option in the UI.  Failing this, I'll have to install something else and I'd rather stick with Time Machine because of a fairly large initial backup (millions of files, TB's of data, already under backup with Time Machine)


Proving $\prod_{i=2}^{i=n} \left(1-\frac{1}{i^2}\right) = \frac{n+1}{2n}$ by induction

So I have to prove the following using induction.  ${\displaystyle \prod_{i=2}^{i=n} \left(1-\frac{1}{i^2}\right)} = \frac{n+1}{2n}$  I showed the basis step that if $n=i=2$, then the two functions are equal $\frac{3}{4}$, and I know that the induction step involves simplifying the function where $n=n+1$. But I'm not sure how to do it with the following algorithm. I am quite confused. Can someone show me how I can prove this in the induction step?


The terms "pretty nice" and "nice" can perhaps not be compared in regards to nicety.  I find "pretty nice" to be a more informal way of relaying that something is rather awesome.  In one way the adverb (?) in this example also tune the somewhat ecstatic adjective down a bit. At the same time I notice the use of, for example, "pretty nice" when it looks like the person intend to say "very nice" – which in turn is not to tune down. Can one perhaps say that "pretty nice" in general means "very nice"? (Thus nicer the nice. :P)


How do you document sites for future maintenance?

I am happy to maintain the sites that I create for customers, but I want to make sure their site will be maintainable into the forseeable future, no matter who maintains it, be it me or someone else.  Suppose, WLOG, the site is running on a VPS somewhere.  As the maintainer, certain aspects of the site's configuration are important to know about (in no particular order):   VPS login credentials (username and password / SSH key) SQL root password Web server setup (apache vs nginx, htdocs locations if the VPS services multiple different domains, etc., any customized configuration settings) SSL setup (if done via Certbot, otherwise expiry date and any other relevant details) Whether site's files exist in a git repository (I almost always run git init inside the htdocs folder just to get some level of source control and safety) Any other unique aspects of the site's functionality such as SystemD daemons necessary for its operation, etc, etc.   How do you document all of this for the future maintainer?


Continuity of a function in $\mathbb{R}$

Suppose $f\colon [a, b] \to \Bbb R$ is continuous. Define $F(x):= \sup \{f(y)\mid y \in [a, x]\}$. Prove $F(x)$ is continuous.   What I have so far:  For $x \le b$, the set $\sup\{f(x)\mid y \in [a, x]\} \not= \emptyset$. By Completeness then, $\sup\{f(y)\mid y \in [a, x]\}$ exists and is finite. So by the Intermediate Value Theorem, there exists a $x_0\in [a, x]$ such that $f(x_0) = s_{0_k}$, where $s_{0_k} = \sup\{f(x)\mid y \in [a, x]\}$.  Then choose a sequence $\{s_n\}$ in $[a, x]$ such that $s_n\to s_{0_k}$. Since there exists a sequence in a closed, bounded set that converges to the supremum of that set.  Also then $s_{0_k}\in [a, x]$ by the Comparison Theorem. And since $f$ is continuous, $\lim f(s_n) = s_{0_k}$.   Observe that as $x_n\to b$ as $n \to \infty$ and that $s_{0_k}$ is monotone increasing. Thus each $s_{0_k}\to s_0$ where $s_0=\sup\{f(y)\mid y \in [a, x]\}$. Thus each $s_{0_k}\to s_0$, hence $F(x)$ is continuous at each $s_{0_k} \in [a, b]$.  First off, is this correct? Secondly, It seems to me there is a simple answer, but I can't see it any ideas?


What does the Visual Studio "Any CPU" target mean?

I have some confusion related to the .NET platform build options in Visual Studio 2008.  What is the "Any CPU" compilation target, and what sort of files does it generate? I examined the output executable of this "Any CPU" build and found that they are the x86 executables (who would not see that coming!). So, is there any difference between targeting executable to x86 vs. "Any CPU"?  Another thing that I noticed, is that managed C++ projects do not have this platform as an option. Why is that? Does that mean that my suspicion about "Any CPU" executables being plain 32-bit ones is right?


Center grooves with mirror and Subsurf Modifiers

SOLVED BY SHADY PUCK = AN UNDELETED FACE IN THE CENTER    Delete that face & Reapply Modifiers


tabularx works on its own but not as a new environment

I am creating a new environment. At the moment it uses tabular and I want to port it to tabularx.  An isolated tabularx table works, but the same table used as an environment fails to compile.  \documentclass{article} \usepackage{tabularx} \begin{document}  \newenvironment{asidex}% {%     \begin{tabularx}{0.5\textwidth}{|l|} }% {%     \end{tabularx}% }  \newenvironment{aside}% {%     \begin{tabular}{|l|} }% {%     \end{tabular}% }  \begin{aside}  % <------------------------ change this to asidex     xxx \end{aside}    % <------------------------ change this to asidex  \begin{tabularx}{0.5\textwidth}{|l|} % <-- this plain table works foo \end{tabularx}  \end{document}   In the above, aside works, but if you change the envionment to use asidex, it fails to compile with  ! Missing } inserted. <inserted text>                  } l.27 \end{tabularx}   What's odd is that the begin...end seems like it should be reproducing the "plain table" at the bottom. The plain table compiles, but the same table when produced for the asidex environment doesn't.  What's happening here?


How to prove that the sequence $n^{1/n}$ converges to 1

Help me in proving that the sequence $n^{1/n}$ converges to $1$


Adding Single Backslash to Regex Pattern in Python

So I have a regex pattern:  no = 'C 030234(A) ZMM'  pattern = '\d{1,2}(\s*)' + no   What I need to do is add a backslash before the ')' and '(' characters in the variable, no, to make the literals.   I tried something like  tList = [] for c in no:   if np.logical_or(c=='(',c==')'):     tList.append('\\'+c)   else:     tList.append(c)   no = "".join(tList) pattern = '\d{1,2}(\s*) ' + no   But this yields a regex pattern of   '\d{1,2}(\s*)C 030234\\(A\\) ZMM'   I need to find away to any string in the form of no, and add a escape character before any parenthesis to make the proper regex pattern  '\d{1,2}(\s*)C 030234\(A\) ZMM'


An interesting exercise about converging positive series, involving $\sum_{n\geq 1}a_n^{\frac{n-1}{n}}$

Yesterday I stumbled across an interesting exercise (Indam test 2014, Exercise B3):     (Ex) Given a positive sequence $\{a_n\}_{n\geq 1}$ such that $\sum_{n\geq  1}a_n$ is convergent, prove that $$ \sum_{n\geq  1}a_n^{\frac{n-1}{n}}$$ is convergent, too.   My proof exploits an idea from Carleman's inequality. We have: $$ a_n^{\frac{n-1}{n}}=\text{GM}\left(\frac{1}{n},2a_n,\frac{3}{2}a_n,\ldots,\frac{n}{n-1}a_n\right) $$ and by the AM-GM inequality $$ a_n^{\frac{n-1}{n}}\leq \frac{1}{n}\left(\frac{1}{n}+a_n\sum_{k=1}^{n-1}\frac{k+1}{k}\right)\leq \frac{1}{n^2}+\left(1+\frac{\log n}{n}\right)a_n $$ hence $$ \sum_{n\geq 1}a_n^{\frac{n-1}{n}}\color{red}{\leq} \frac{\pi^2}{6}+\left(1+\frac{1}{e}\right)\sum_{n\geq 1}a_n.$$  Now my actual      Question: Is there a simpler proof of (Ex), maybe through Holder's inequality, maybe exploiting the approximations   $$ \sum_{m<n\leq 2m}a_n^{\frac{2m-1}{2m}}\approx \sum_{m<n\leq 2m}a_n^{\frac{n-1}{n}}\approx \sum_{m<n\leq 2m}a_n^{\frac{m-1}{m}}$$   "blocking" the exponents over small summation sub-ranges?


How to select and copy text by pressing long in textView?

I'm working in Android Studio 3.0.1. I created a EditText in which I write a text now I want when user long press that text it get copied in clipboard.  I used a method here (which is not working)   ClipboardManager mClipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);         mEditText.setText(mClipboard.getText());  It says Method Invocation 'get text' may produce 'java.lang.NullpoinyerException' I need help what should i do ?


use calculation as the condition in loop

I've a script named t.sh as below:  #!/bin/bash  num=2 for i in {0..$((num-1))}; do         echo 'aaa' done  for i in {0..1}; do         echo 'bbb' done   The output of ./t.sh:  aaa bbb bbb   I can't understand at all. $((num-1)) equals to 1, so I think aaa should be printed twice, just like bbb, why it shows only once?


I'm a software developer, and I'm trying to publish some open source software on my site. My software is designed for Windows users, so I want to use a single file "setup.exe" or something likewise.  I currently have a test application and I've created an installer with: "Inno Setup 5" (I'm not attached to that program, so if you know a better one I'll try that) and published it on my site (here).  But when I try to download it chrome says:"setup.exe is not commonly downloaded and could be dangerous." this scares away people, and I can't have that. And when I do confirm that I want to keep it (by clicking the small arrow on the side) and I install it, Windows (SmartScreen) says:"Windows protected your PC".  I need to get rid of both these errors, and I can't find a working solution. Please help.


Passing multidimensional array to a function using a variable as a parameter

Sorry if this is really easy to fix or a stupid question but I've only recently started programming.   So basicly in void main() I've declared a 2D array like so:  void main() {   const int grid = 5;   array[grid][grid]; {   However I would like to pass this into a function like this:  void drawGrid(int grid, bool array[][]) {  }   This creates an error as the second parameter needs to have a number. But that's a problem since in main I declared my array using a variable.  void drawGrid(int grid, bool array[grid][grid]) {  }   Putting variables in the parameters does not work.  How do I go about passing the array to this function whilst using the int variable grid inside the parameters.   I have searched a lot and looked at answers from people who had similar problems to me but I just could not seem to figure out what to do specifically. Could anyone please show me how to fix the problem, I'd be incredibly greatful as I've been trying to work this out for almost two hours now. Thanks.


I use Blender with my iMac Late 2012 and I have the graphics card NVIDIA GeForce GTX 660M. In the internet it says, that this graphics card has CUDA but however I cannot change the 'Compute Device' in my User Preferences. Anyone an idea?


Which postulate of GR requires that $ds^2=g_{\mu\nu}(x)dx^\mu dx^\nu$ must be invariant?

The postulate that the velocity of light in a vacuum is the same in all inertial frames, can be exploited to establish that the spacetime interval between two events $x^\mu=(ct,{\bf r})$ and $x^\mu+dx^\mu=(ct+cdt,{\bf r}+d{\bf r})$ defined as $$ds^2=\eta_{\mu\nu}dx^\mu dx^\nu=c^2dt^2-d{\bf r}^2\tag{1}$$ remains invariant. In general relativity, we require $$ds^2=g_{\mu\nu}(x)dx^\mu dx^\nu \tag{2}$$ to be invariant. Which postulate of general relativity gives rise to this requirement?


Exclamation mark in the bash script vs in the terminal

I have a simple bash script called foo.sh like this: #!/bin/bash  echo "Foo!"  When I run it as ./foo.sh I get the Foo! message and everything's fine. But if I echo "Foo!" directly from the console, then I obtain the expected behavior and message: bash: !": event not found. I understand that the ! is presented as a previous command and if used inside p.e. single quotes, then it's considered as a literal. I'm just wondering what is the difference here that running a script with that echo "Foo!" (even with source ./foo.sh works but directly from the console it doesn't.


Open local HTML files in compatibility view (IE7) in IE11/WIN7

Friend of mine has an interesting issue on his new corporate PC - it looks like his IE11 is somehow configured to open all HTML files from the local file system in compatibility mode (IE7).  While I'm aware of the Compatibility View for the specific web-sites and UNC paths, compatibility meta tag and "saved from" comment, it looks like all of these options are not applied here. The computer's options are hidden so I cannot examine them.  I've Googled for a solution but the most relevant result was to use the "display all sites in compatibility mode" option in IE8 (which is not applicable to IE11).  I can see two alternatives:   Somehow the filter for all the local files is added to the Compatibility View settings (I've tried it on my machine, but it just does not allow the file://* pattern) Somehow the local files are marked as intranet and the compatibility view is turned on for all intranet websites. There is a filter for that which allows file:\server\share patterns but it looks like it does not allow the pattern file://* as well.   Do you know how to configure IE7 mode to be the default one in IE11?  This very simple file demonstrates the issue:      If the page is in the IE7 mode, the IMG path will be absolute in the message box.


I installed postgres. It created a user account. I don't need postgres anymore. What are the steps I have to proceed to uninstall it completely from Ubuntu 14.04? (I didn't install the software over the Software-Center.


I'm using the most up-to-date version of firefox and flash player.  When I go on 4oD and press play I used to get the loading screen showing forever with nothing playing. I then had a search and someone suggested to turn off Ad-Block. So I did and it plays the advertisements. Once the last ad has played it does nothing.   Has anyone else got this problem? Has anyone managed to fix it?  Any help would be appreciated.  Thanks.


why is PI considered irrational if it can be expressed as ratio of circumference to diameter?

Pi = C / D (circumference / diameter) . I have read that if circumference can be expressed as an integer then diameter cannot and vice-versa, so that the ratio can never be expressed as a/b where both a,b are integers & hence Pi is irrational.  However as far as i know a ratio of two decimals can always be expressed as a ratio of two integers by adding 0s after the deciaml. eg- 56.89 / 23 can always be written as 5689/2300 . So we should also always be able to express C/D as integers . Why then is Pi irrational ? Can't we always measure the diameter and circumference accurately and express them as integers in the ratio ?


prove that Petersen graph has no cycles less than or equal to 4

I studying the proof that the Petersen graph is not Hamiltonian, and in the proof, they used an observation that seems intuitively correct but I want to provide rigorous proof for it, given that I'm taking an introductory course to discrete mathematics.  Claim: Petersen graph has no cycles less than or equal to 4  I want to prove it by contradiction using the basics ideas, can you help me with that?


How to align the div and iframe in the center?

I am trying to embed lucid chart and show it as a pop-up in an iframe. It is somehow not getting aligned in the center though. And it's not responsive to the varying screen sizes as well. Can anyone please help me with it? <div class="popup" style="width: 960px; height: 720px; position: relative; text-align:center;">     <iframe allowfullscreen frameborder="1" style="width: 960px; height: 720px; position: absolute; text-align:center;"         [src]="embedUrl | urlSanitizer" id= {{embedId}}>     </iframe> </div>  It's getting aligned to the right of the page and only half of it is visible as of now. CSS looks like this .popup {   position: relative; }


NullPointerException in Java Mysql querying

I'm new to java programming and I'm making a project which implies the use of java and mysql and I cannot manage to fix a NullPointerException in this piece of code, can anyone help me?  here's the full code, the connection part is working fine, its tested  package database; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList;  import database.mainConnection;  public class userUtils extends mainConnection {      public static void main(String[] args ) throws Exception {         userLogin("mattia",hash("password");      }       /*public static Boolean registerUser(String name, String surname, String username, String email, String password, String Affiliation, String dateOfBirth) throws Exception {         Connection con = getConnection();         // 0000-00-00 format date          PreparedStatement query = con.prepareStatement("INSERT INTO users (UserID, Username, Email, Password, Name, Surname, BirthDate, Affiliation) VALUES (?,?,?,?,?,?,?,?)");          query.executeUpdate();         return false;     }*/      public static Boolean userLogin(String username, String password) throws Exception {         Boolean bool = null;         try{             Connection con = getConnection();             PreparedStatement query = con.prepareStatement("SELECT * FROM users WHERE Username=? AND Password=?");             query.setString(1, username);             query.setString(2, password);              ResultSet result = query.executeQuery();              if(result.next()) {                 bool = true;             }              } catch(Exception e) {                 e.printStackTrace();                 }         return bool;     } }   Also it doesn't give any results back, but i guess its due to the nullpointerexception  the error points at   con.prepareStatement("SELECT * FROM users WHERE Username=? AND Password=?"); and at a printlnine where i invoke the method


What is the functional difference between sudo su and sudo -i?

Why is one preferred over the other in this example?  sudo su echo "options iwlwifi 11n_disable=1" >> /etc/modprobe.d/iwlwifi.conf exit   Please provide links to Ubuntu documentation.


Can you cast silent image around someone, blinding them if they fail their save?

I am playing as a Warlock with the Misty Visions Eldritch Invocation. I see a group of enemies, and I cast Silent Image to create a 15 x 15 rock in the space(s) that they are occupying. If they succeed on their saving throw, they'd be able to see through it, but if they fail, they should be blind? Shouldn't they? Maybe they see rock right in from of their eyes, what if I cast an image of Obsidian?, or Basalt? or Black Concrete? Can I blind them, or make them think they are blind?  Misty Visions Description:  You can cast silent image at will, without expending a spell slot or material components  Silent Image Description:  You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube. The image appears at a spot within range and lasts for the duration. The image is purely visual; it isn't accompanied by sound, smell, or other sensory effects. You can use your action to cause the image to move to any spot within range. As the image changes location, you can alter its appearance so that its movements appear natural for the image. For example, if you create an image of a creature and move it, you can alter the image so that it appears to be walking. Physical interaction with the image reveals it to be an illusion, because things can pass through it. A creature that uses its action to examine the image can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC. If a creature discerns the illusion for what it is, the creature can see through the image.


I'm trying to create a Horizontal Probability Tree with Level Labels using tikz. (Not tikz-qtree). Right now, I have a horizontal tree. The labels are NOT aligned to the top of the diagram. I would like to have all the labels aligned without having to manually tweak positions.   Here is the MWE:  \tikzstyle{level 1}=[level distance=3.5cm, sibling distance=3.5cm] \tikzstyle{level 2}=[level distance=4.5cm, sibling distance=1.5cm] \tikzstyle{level 3}=[level distance=3.5cm, sibling distance=2cm]   \tikzstyle{bag} = [text width=4em, text centered] \tikzstyle{end} = [rectangle, draw=none, minimum width=3pt, inner sep=0pt]  \tikzstyle{ans} = [color=red]   \begin{tikzpicture}[level distance=5cm, level 1/.style={sibling distance=3.5cm}, level 2/.style={sibling distance=1.2cm}, level 3/.style={level distance = 2cm},grow'=right] \tikzstyle{every node}=[]     \node (Root) [] {Origin}         child [] {         node {Door A}         child { node {A}                  child {node[end] {$0$} }                 edge from parent                 node[left] {$0$}         }         child [black] { node {B}                  child {node[ans,end] {$\frac{1}{6}$} }                 edge from parent                 node[ans,left] {$\frac{1}{2}$}         }         child [black] { node {C}                  child {node[ans,end] {$\frac{1}{6}$} }             edge from parent             node[ans,left] {$\frac{1}{2}$}         }         edge from parent         node[above] {$\frac{1}{3}$}     }     child {         node {Door B}         child { node {A}                  child {node[ans,end] {$0$} }                 edge from parent                 node[ans,left] {$0$}         }         child { node {B}                  child {node[end] {$0$} }                 edge from parent                 node[ans,left] {$0$}         }         child { node {C}                  child {node[ans,end] {$\frac{1}{3}$} }                 edge from parent                 node[ans,left] {$1$}         }         edge from parent         node[ans,left] {$\frac{1}{3}$}     }     child {         node {Door C}         child { node {A}                  child {node[ans,end] {$0$} }                 edge from parent                 node[ans,left] {$0$}         }         child { node {B}                 child {node[ans,end] {$\frac{1}{3}$} }                 edge from parent                 node[ans,left] {$1$}         }         child { node {C}                 child {node[end] {$0$} }                 edge from parent                 node[ans,left] {$0$}         }         edge from parent         node[ans,left] {$\frac{1}{3}$}     };    % How I'm applying labels to each level.    % Need to be able to dynamically align nodes at top level \begin{scope}[every node/.style={above}]  \path (Root    -| Root)  ++(0,15mm) node {Test};  \path (Root-1   -| Root-1)  ++(0,15mm) node {Contestant Chooses};  \path (Root-1-1  -| Root-3-3-1)  ++(10mm,13mm) node {Host Reveals Door};  \path (Root-1-1-1 -| Root-3-3) ++(0,15mm) node {Probability}; \end{scope}   \end{tikzpicture}   I get this    and want this


How to properly edit system files (as root) in GUI (and CLI) in Gnu/Linux?

System: .    Objective: To define  aliases to launch various  and  text editors while opening a file in  mode from  emulator.    Progress  For example, the following aliases seem to work as expected:  For , in this example I used Nano ():  alias sunano='sudo nano'   For , in this example I used Xed ():  alias suxed='sudo xed'   They both open a file as .    Problem  I have an issue with  in conjunction with :  alias susubl='gksudo /opt/sublime_text/sublime_text'   Sometimes it works. It just does not do anything most of the time.  How do I debug such a thing with inconsistent behavior? It does not output anything. No error message or similar.    Question  gksudo has been deprecated in Debian and also no longer included in Ubuntu 18.04 Bionic, so let me re-formulate this question to a still valid one:  How to properly edit system files (as root) in GUI (and CLI) in Linux?  Properly in this context I define as safely in case, for instance, a power loss occurs during the file edit, another example could be lost SSH connection, etc.


Is there a website like Stack Overflow that specializes in code review? I always have code that needs to be reviewed. Is there a specialized website for that?


Two idempotent matrices are similar iff they have the same rank

Definitions: For $F$ a field,   $A,B\in F^{m\times n}$ are equivalent means there exist invertible matrices $Q\in F^{m\times m}$ and $P\in F^{n\times n}$ so that $B=QAP$, $A,B\in F^{n\times n}$ are similar means there exists an invertible matrix $P\in F^{n\times n}$ so that $B=PAP^{-1}$. $[T]_\mathcal{B}$ is the matrix of the linear transformation $T:V\to V$ with respect to an ordered basis $\mathcal B$ of $V$.   I've seen the result that $A,B\in F^{m\times n}$ are equivalent iff they have the same row and column reduced echelon form iff they have the same rank.  I'd like to show that if $A,B\in F^{n\times n}$ are idempotent matrices, they are similar iff they have the same rank.  I've noted that similarity of two matrices implies their equivalence, and hence that they have the same rank. So it remains to show that $rank(A)=rank(B)$ implies $A$ and $B$ are similar.  Observations: If $V$ is a finite-dimensional vector space over field $F$ and $T:V\to V$ is an idempotent linear transformation (i.e. $T^2=T$), then $V=im T\oplus \ker T$ and if $\mathcal B_1=\{v_1,v_2,...,v_m\},\mathcal B_2=\{v_{m+1},...,v_n\}$ are bases for $im T$ and $\ker T$ respectively, then $[T]_{\mathcal B_1\cup \mathcal B_2}\in F^{n\times n}$ is a $1\times 2$ block matrix with $C\in F^{n\times m}$ in the first entry and zero matrix for the other entry, where the $j$th column of $C$ is given by the scalars $a_{1j},...,a_{nj}$ so that $T(v_j)=\sum_{i=1}^n a_{ij}v_i$ (which uniquely define $T(v_j)$ since $\{v_1,...,v_n\}$ are a basis for $V$).  Let $L_A,L_B$ be the linear transformations representing left-multiplication by $A$ and $B$, respectively. Then $A'=[L_A]_\mathcal B$ and $B'=[L_B]_\mathcal B$ take the block matrix form described above, and since $rank (A)=rank (B)$ by assumption, $A'$ and $B'$ have the same row and column reduced echelon form. So starting from the row and column reduced echelon form that they take, we can multiply on the left and right by invertible matrices (by doing the inverse elementary matrix operations that we did to get the reduced forms) to get back to either matrix, i.e. if $D$ is the row and column reduced echelon form for the two, then $QA'P=D=RB'S$ where $Q,P,R,S$ are invertible $n\times n$ matrices.   Hence $B'=R^{-1}QA'PS^{-1}$. We want to show that the $A,B$ being idempotent gives us that $R^{-1}Q=(PS^{-1})^{-1}$. This is where I'm stuck.  Any help would be greatly appreciated! Thanks in advance


I have an archive page that displays the number of articles published. Because there were so many, I ran a pagination script:  for 127.0.0.1/archive/2/?p=x&pp=y  where p is the page number and pp is number of articles to display per page.  The pagination looks like this:  Prev  1  2  3  4 ... 12   NEXT   with each item linking to p like x.  I also have the items per page setter: 25 | 50 | 100 (y).  Now I have a PHP script that fixes pp into a session variable. But I am worried about duplicate content (since incrementing pp values will be inclusive) and also content not getting indexed because its not in the pagination link. so in the example above, pages 5-11 will not be indexed.   Any ideas on how to fix this?


How can I get a Class object form primitive?

Obviously this is possible (as Class has isPrimitive() method) but how I can do this directly? E.g. reflection api able to cast a primitive type to Class: import java.lang.reflect.Method;   public class TestClass {                 public static void m(){}         public static void m(Object o){}         public static void m(int i){}         public static void m(Integer i){}                 public static void main(String[] args){                                 TestClass tc=new TestClass();                 Method[] mtds=tc.getClass().getDeclaredMethods();                                 for (int i = 0; i < mtds.length; i++) {                         System.out.print(mtds[i].getName());                         Class[] prms=mtds[i].getParameterTypes();                         for (int j = 0; j < prms.length; j++) {                                 System.out.print("-"+prms[j].getCanonicalName());                                                                 }                         System.out.println();                 }                 } }  output is:  m m-java.lang.Object m-int m-java.lang.Integer main-java.lang.String[]  Integer and int are different so it is not autoboxing. Anything (except creating an utility class with reflection and getParameterTypes() ) do not come at my mind (everything else I've tried failed).


Can't get Dryad to move into house in mushroom biome for 3ds

I've built a house in a mushroom biome that I want my Dryad to move into from a different house, so that I can buy mushroom grass seeds. The banner appears in the mushroom biome house, but she won't go there.   How can I get her to move in?


Why does my code work, when I use " in the following code:  for(int i=0;i<7;i++){         if(grid[row][i]!=0){             if(player == "yellow"){                 grid[row][i-1] = 'y';             }             else if(player == "red"){                 grid[row][i-1] = 'r';             }         }     }   But don't work, when I use ' in the following code:  for(int i=0;i<7;i++){         if(grid[row][i]!=0){             if(player == 'yellow'){                 grid[row][i-1] = 'y';             }             else if(player == 'red'){                 grid[row][i-1] = 'r';             }         }     }   It is always saying, "Invalid character constant".    - grid is a 2 dimensional char variable    - row is an interger    - player is the super class (window) protected and in the constructor of the super    class occupied with the value yellow:  protected String player;  public window() {     player = "yellow"; }


The number of questions and answers on my network profile is off by one

While I'm writing this question, I've written  on this site:  Yet my network profile shows :  I don't think it's a caching issue, as I've checked the profiles of users who posted something today and their counts have been properly updated. My  is ~30 hours old. Deleted posts might play a role, but my  is from last November, and none of my questions has been Roomba'ed since. My  is somewhat newer (24 hours).  After I posted this (my 302nd) question, the number of questions on my network profile had immediately increased by 1, to 301, so it is updated but it's still off by one. A year later, the problem still persists, but I now noticed it also happens to my MathOverflow account; the network profile says 16 answers:  one more than my site profile (15 answers):


Insert all the images at once of a specific folder

I would like to insert in my latex document almost 100 Fotos (at once), which are inside a folder, but if it is possible, just with few commands.   Now, I wont like to use:   begin{figure}>includegraphics{folder/figure001.jpg}>end{figure} then again begin{figure}>includegraphics{folder/figure002.jpg}>end{figure} and so on until figure100.jpg.  Is there a easy way to write a command that takes all the images of a specific folder and insert all of them on the .tex document?  Thanks and greetings.


What “National Identification Number” to enter in an ESTA application, for a German?

I’m trying to complete an ESTA application (German citizen). One of the questions asked is about a National Identification Number, with this explanation:     Enter the number on your identity document, other than a passport, issued by your country. The National Identification Number, if issued to you, is required to complete the application. If you do not have a National Identification Number, enter UNKNOWN.   This leaves me wondering what I should enter. “Number on your identity document, other than a passport,” sounds like they are asking for the identity card number (Personalausweis). The term “identification number”, on the other hand, rather makes it appear like a permanent identifier such as the tax payer identification number (Steuer-Identifikationsnummer). It’s also conceivable that neither is applicable and I should enter unknown instead.  I’ve tried searching for further information on the embassy’s website, but found this number ; apparently the question was added to the form less than a year ago, which might explain why I only find few mentions elsewhere on the web, and they are all inconclusive.  Interestingly, this question appears only after I’ve selected the country of citizenship (Germany in this case), and it does not appear for many other countries; e.g., this question is asked for citizens of the Netherlands or South Korea, but not of Austria, Switzerland, Sweden or the UK.


Why are Alkaline, NiMH, and Li-ion AA measured differently (mAh, mWh, etc)?

Looking around Amazon, it seems that different types of batteries are measured differently:  Does anyone know why?   Li-ion are measured in mWh    (Cheap-Os)  3000mWh AmpTorrent  NiMH are measured in mAh      Alkalines are typically not measured   "Long Lasting" Duracell "Longest Lasting" Energizer    I assume that Alkalines are not measured for some sort of historical reason with marketing departments?  ... or is it that alkalines so mystical and unreliable that giving them a measurement is too aggressive? Or that switching to non-toxic / non-mercury was such a bad move in performance that measurements had to be removed in the 90s so people wouldn't know?  Perhaps NiMH are measured in mAh because the voltage can very so greatly and mWh doesn't make sense?  Are Li-ion measured in mWh because that's more consistent with non-battery measurements and they do deliver reliable voltage?


How to make an application(exe) of a python file that inherits another python file

In my calculator directory, I have  finalCalc_main.py  which imports class from another file  finalCalc.py  which has my Ui_MainWindow class. How can I make an exe. file using pyinstaller?


I know that "myself" is a reflexive pronoun and can also be used for emphasis.  When writing something to the tune of "I myself would love to go hiking."  Wouldn't it be proper to use it as an interjection "I, myself, would like to go hiking." An interjection of this sort would typically clarify to whom the pronoun is referring, however "I" is already a clear indicator of who I am, without the "myself" attached.    TL;DR:  Shouldn't I be using interjection commas for the phrase "I, myself, ..."?


"E:Read error - read (5: Input/output error), E:The package lists or status file could not be parsed or opened."

So I keep trying to install things on my laptop and whenever I try to use sudo apt-get I get the same errors every  time,  SystemError: E:Read error - read (5: Input/output error), E:The package lists or status file could not be parsed or opened.   Also whenever I try to open software Center through my desktop Icon it will just freeze leaving me to force quit.  If I try to use the command software-center in my terminal I get the longest list in the world which is,   che.open() Traceback (most recent call last):   File "/usr/lib/python2.7/dist-packages/gi/overrides/GLib.py", line 629, in <lambda>     return (lambda data: callback(*data), user_data)   File "/usr/share/software-center/softwarecenter/db/pkginfo_impl/aptcache.py", line 261, in open     self._cache = apt.Cache(progress)   File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 105, in __init__     self.open(progress)   File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 150, in open     self._cache = apt_pkg.Cache(progress) SystemError: E:Read error - read (5: Input/output error), E:The package lists or status file could not be parsed or opened. 2013-10-13 10:13:52,685 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open() Traceback (most recent call last):   File "/usr/lib/python2.7/dist-packages/gi/overrides/GLib.py", line 629, in <lambda>     return (lambda data: callback(*data), user_data)   File "/usr/share/software-center/softwarecenter/db/pkginfo_impl/aptcache.py", line 261, in open     self._cache = apt.Cache(progress)   File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 105, in __init__     self.open(progress)   File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 150, in open     self._cache = apt_pkg.Cache(progress) SystemError: E:Read error - read (5: Input/output error), E:The package lists or status file could not be parsed or opened. 2013-10-13 10:13:57,365 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open() Traceback (most recent call last):   File "/usr/lib/python2.7/dist-packages/gi/overrides/GLib.py", line 629, in <lambda>     return (lambda data: callback(*data), user_data)   File "/usr/share/software-center/softwarecenter/db/pkginfo_impl/aptcache.py", line 261, in open     self._cache = apt.Cache(progress)   File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 105, in __init__     self.open(progress)   File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 150, in open     self._cache = apt_pkg.Cache(progress) SystemError: E:Read error - read (5: Input/output error), E:The package lists or status file could not be parsed or opened.   That's only about one-tenth of the list which is too long to read. I need help, if anyone has an answer please respond


This question arises when I try to describe my itinerary to ticket service in the UK. Take for example, I plan to buy a ticket from A to B. B is the terminal. How to say its counter part A? I cannot find a proper term. I have to say "I will depart from A" or "I plan to go to B from A". Or I even use "departure place" to refer to B.


How to spawn a process and capture its STDOUT in .NET?

I need to spawn a child process that is a console application, and capture its output.  I wrote up the following code for a method:  string retMessage = String.Empty; ProcessStartInfo startInfo = new ProcessStartInfo(); Process p = new Process();  startInfo.CreateNoWindow = true; startInfo.RedirectStandardOutput = true; startInfo.RedirectStandardInput = true;  startInfo.UseShellExecute = false; startInfo.Arguments = command; startInfo.FileName = exec;  p.StartInfo = startInfo; p.Start();  p.OutputDataReceived += new DataReceivedEventHandler (     delegate(object sender, DataReceivedEventArgs e)     {         using (StreamReader output = p.StandardOutput)         {             retMessage = output.ReadToEnd();         }     } );  p.WaitForExit();  return retMessage;   However, this does not return anything. I don't believe the OutputDataReceived event is being called back, or the WaitForExit() command may be blocking the thread so it will never callback.  Any advice?  EDIT: Looks like I was trying too hard with the callback. Doing:  return p.StandardOutput.ReadToEnd();    Appears to work fine.


There have already been a lot of questions on this site on diffraction but I still believe this one might be slightly different. In electromagnetic waves, diffraction and any other phenomenon of wave propagation can be solved by Huygen's principle, a geometric construction that asks us to consider all points on a wavefront as secondary sources of wavefront. A justification of this treatment is provided by Feynman:-        I understood this completely. But then diffraction is a very general   phenomenon. What if we talk about mechanical waves (sound waves) then   this treatment by superposing the fields produced by opaque and a   hypothetical plug is no longer valid, but the diffraction details are   similar. Why then on an intuitive level is there diffraction, details   of which can be worked out by considering secondary sources?


Remap Caps Lock to AltGr / Alt+Ctrl on Windows?

Does anyone know how to remap Caps Lock to AltGr/Alt+Ctrl on Windows 7?  Closest I've come to solving it is using SharkKeys, but if I try to map anything with AltGr it says SharpKeys doesn't know about the key.  Here's the old bug report about it:   I've been searching a lot, but all the registry hacks are how to map it to Shift or Ctrl, nothing about AltGr.


Large braces for specifying values of variables by condition

How do I produce a conditional expression with large brackets? For example: X = 0 if a=1, 1 otherwise, with a large left bracket and specifying each condition in a line?


Response anomaly after process repeats three times

This is my full code:  from random import randint currency = float(5.0) while currency > 0:     start = input("Do you wish to gamble? Y/N ")     if start == "Y":         numbers = []         currency = currency - 0.2         di = randint (1,6)         numbers.append(di)         dice = randint (1,6)         numbers.append(dice)          thrice = randint (1,6)         numbers.append(thrice)         print(numbers[0])         print(numbers[1])         print(numbers[2])         if numbers[0] == numbers[1] or numbers[0] == numbers[2] or numbers[1] == numbers[2]:             currency = currency + 1.0             print("You win £1!","Your current balance is: £",currency)         elif numbers[0] == numbers[1] and numbers[0] == numbers[2]:             currency = currency + 2.0             print("Jackpot! You win £2!","Your current balance is: £",currency)         else:             print("Too bad!","You're currency is: £",currency)     elif start == "N":         print("Your final total was: £",currency)         break     else:         print("Invalid Response")   And the response I get after accepting as "Y" three times is:  Do you wish to gamble? Y/N Y 1 6 2 Too bad! You're currency is: £ 4.8 Do you wish to gamble? Y/N Y 2 4 2 You win £1! Your current balance is: £ 5.6 Do you wish to gamble? Y/N Y 1 1 6 You win £1! Your current balance is: £ 6.3999999999999995   I do not understand why this is happening, the code checks out, and this issue repeats consistently on the third run no matter the outcome of the RNG and will always end in number.999999999999995.


I have a texture that I want to give an actual depth. However, I dont want to use Displacement because it requires very high polygon count to work properly and it slows down render times which is quite annoying.  I know there is a method of doing this called "Parallax Mapping" and is used in some video games but I cant find a way of doing this in Blender.  I've put an example to show you what I want to achieve:   This is a 2D texture on a 2D plane that has only 4 vertices.   This is the result I want to achieve without increasing the polygon count.  (To demonstrate the second image, I simply used the Array-Modifier and set the offset to 1 mm and the count to 1000! Obviously, this wont work on curved meshes, slows down the performance in the viewport and it has some side effects if you look from the side...)    Looks like a hologram with vertical sync issues, lol


Axiom of Choice : Is it Axiom? or Trivial Fact?

This question might be rude or inappropriate, but I am very beginner of studying mathematics.  Today I had learned the concept of Axiom of Choice, which states that $ \forall$ nonempty indexed set $S_i$, there $\exists$ indexed family of element $x_i$ where $\forall x_i \in Si$.   To me, at first it reached out to me as a just mere fact, but can't understand why this axiom must have been accepted as an axiom.   It's little confusing to me.  To wrap up the notion of this OP, it could be summarized as below:   Why does the concept of axiom of choice must be accepted as axiom? What makes a statement to be valued to be designated as an axiom?


I'm supposed to prove this. The answer key doesn't tell me anything more than to add zero:  $(a+(-a))$   to:  $(-1)\cdot a$  and use that:  $a=a\cdot 1$  I have these axioms to my disposal:  (A1) for all $x,y$ we have $+y=y+x$  (A2) for all $x,y,z$ we have $(x+y)+z=x+(x+z)$  (A3) there exists a number $0$ so that for all $x$ we have $x+0=x$  (A4) for all $x$ there exists a number $a$ so that $x+a=0$  (M1) for all $x,y$we have $x*y=y*x$  (M2) for all $x,y,z$ we have $(x*y)*z=x*(y*z)$  (M3) there exists a number $1=/=0$ so that for all $x$ we have $x(1/x)=1$  (M4) for all $x=/=0$ there exists a number $b$ so that $x(1/x)=1$  (AM) for all $x,y,z$ we have $z*(x+y)=z*x+z*y)$  $a ∈ R$


Apostrophe or not —“Iraqi Translators Association” or “Iraqi Translators’ Association”?

I found apostrophe use differs among association titles—"American Translators Association" has no apostrophe, whereas  "Iraqi Translators' Association" does.  Therefore, I need to make sure which one of the following is correct:  "Iraqi Translators Association" or  "Iraqi Translators' Association"?  .


"The fact of its being so rare a flower ought to have made it easier to trace the source of this particular specimen, but in practice it was an impossible task."    I just found this sentence reading a book and it sounds weird to me. I understand the meaning, but I've never seen or studied this structure in English before. I did some research on the Internet but I could find nothing. Could anyone  explain the grammar? Could you please provide more examples with the same structure?


Retrieving Owner.Name from List of objects

I am trying to retrieve the following fields Owner.Name, Name, Id from ActionPlanTemplate object and returning a list. However, when the list is returned, I do not get Owner.Name in the ActionPlanTemplate object.  How can I get the Owner.Name in the ActionPlanTemplate list for each object?  When I enter the same query in Query Editor, I get the correct results.  String test = 'SELECT Owner.Name, Name, Id from ActionPlanTemplate';  List<ActionPlanTemplate> apt = database.query(test);  System.debug(apt);   This returns:     (ActionPlanTemplate:{OwnerId=0031W000019AA3qWBF, Name=APT Test, Id=0WS5E0000000044WAA}, ...   EDIT: After reading the recommended solutions, Yes Owner.Name can be called when I refer to it directly as object.Owner.Name, however I am trying to display this component as a value in my lightning data table column.  component.set('v.APcolumns', [         {label: 'Action Plan Template Name', fieldName: 'linkName', type: 'url', typeAttributes:{ label: { fieldName: 'Name'} }, target:'_blank', sortable: 'true'},         {label: 'Template Owner', fieldName: 'Owner.Name', type: 'text'}     ]);   The Action Plan Template name shows up, but not the Owner.Name


How much memory should be allocated to root, swap and home?

I want to create partition in ubuntu for root swap and home.... if i take, say 15GB of memory from windows disk management then how much should I assign for each of them(root,home and swap)?


Is it normal that occasionally Page Life Expectancy drops to 0 and queries start giving timeouts in SQL Server?

Can somebody shed some light on if it's normal that Page Life Expectancy drops occasionally to 0 in SQL Server (2014) resulting in slow queries and timeouts?  I'm facing this on my developer machine when developing a web application and I don't know whether it is because of the development environment or something else. PLE may be over 10000 for one day or a couple of hours (during which queries work fast) until it drops to 0 and all my queries go from 15ms to 40 seconds or more.  I mean is there any way to control the performance of SQL Server in this matter or is this by design of the SQL Server that it may get slow, for example, due to memory pressure until it comes faster again etc.?   To me it looks like queries are read in a cache and at some point they're flushed out and queries start giving timeouts because everything is read from a disk. Is this something that can be avoided?


Teen novel about a boy challenging Death, including a bowling match

I'm trying to track down a novel I read in my junior high days, which would put it at mid-to-late 80s. I don't remember the overall plot of the novel, but I remember the protagonist ended up matching wits against Death in various games - including a bowling match, of all things. The kid was being helped by a group of weird characters & creatures, and the rules of the world he was in were all screwy. It definitely had a fantasy genre bent to it - wasn't sci/fi or drama. It also wasn't a "Choose-Your-Own-Adventure" book, which I absolutely loved at the time - it was a regular novel with a linear plot.  I was a big fan of AD&D at the time, so I'm thinking it might have been set in the Planescape "universe", which would have explained all the weird characters & rules of reality. I've had no luck finding it based on that, however. I've also had no luck searching for "bowling" + "death"... all I get are a bunch of weird news reports about people dying while bowling.  Does the "bowling with death" thing ring a bell for anyone?


trigger on Question object gives below error during the deployment

I have been getting below error when trying to deploy new changes from sandbox to production.  chatter_answers_question_escalation_to_case_trigger: trigger body is invalid and failed recompilation: Entity is not org-accessible  Stack Trace: null  This is a trigger on Question (chatter Question) object which I can't find it after summer 16 release. Last successful deployment was on 06/09 and only change we did since yesterday was recompiled all classes and ran All tests.   Any help is greatly appreciated.


I've plotted 5 plots individually, but I'd like to have something like in the picture:  where the y_max and the ymin is always the same and goes from 0.651 to 0.6535, but on different level like in the picture. The x axis goes from 19.0 to 19:2. 'Till now I wrote only separately cause I can't make it work.  \documentclass[a4paper,12pt]{book} %\usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[english,italian]{babel} \usepackage{url,amsfonts,epsfig} \usepackage{amsmath} \usepackage{caption} \usepackage{subcaption}  \usepackage{matlab-prettifier}   \usepackage{fancyhdr} \pagestyle{fancy} \renewcommand{\footrulewidth}{0.5pt} \fancyhead[]{}  \fancyhead[LO]{\nouppercase{\rightmark}}  \fancyhead[RE]{\nouppercase{\leftmark}}  \fancyfoot{} \fancyfoot[LO,RE]{\thepage}    \renewcommand{\sectionmark}[1]{\markright{#1}} \parindent 0ex    \usepackage{tikz} \usepgflibrary{arrows.meta} \usetikzlibrary{calc,quotes,angles}  \usepackage{pgfplots} \usetikzlibrary{calc}   \begin{document}  \begin{figure}[h]     \centering     \begin{tikzpicture}[yscale=0.6]     \begin{axis}[name=plot,     xmin=19, xmax=19.2, xlabel={$[s]$}, ylabel={$Ampiezza$},     ymin=0.651,ymax=0.6535,width=1\textwidth]     \addplot[blue,mark=.] table{10Hz.txt};     \end{axis}     \end{tikzpicture}     \caption{\textit{Oscillazioni a 10Hz}}   \label{fig:10Hz}      \begin{tikzpicture}[yscale=0.6]     \begin{axis}[name=plot,     xmin=19, xmax=19.2, xlabel={$[s]$}, ylabel={$Ampiezza$},     ymin=0.651,ymax=0.6535,width=1\textwidth]     \addplot[blue,mark=.] table{20Hz.txt};     \end{axis}     \end{tikzpicture}     \caption{\textit{Oscillazioni a 20Hz}}   \label{fig:20Hz}      \begin{tikzpicture}[yscale=0.6]     \begin{axis}[name=plot,     xmin=19, xmax=19.2, xlabel={$[s]$}, ylabel={$Ampiezza$},     ymin=0.651,ymax=0.6535,width=1\textwidth]     \addplot[blue,mark=.] table{30Hz.txt};     \end{axis}     \end{tikzpicture}     \caption{\textit{Oscillazioni a 30Hz}}   \label{fig:30Hz}      \begin{tikzpicture}[yscale=0.6]     \begin{axis}[name=plot,     xmin=19, xmax=19.2, xlabel={$[s]$}, ylabel={$Ampiezza$},     ymin=0.651,ymax=0.6535,width=1\textwidth]     \addplot[blue,mark=.] table{40Hz.txt};     \end{axis}     \end{tikzpicture}     \caption{\textit{Oscillazioni a 40Hz}}   \label{fig:40Hz}      \begin{tikzpicture}[yscale=0.6]     \begin{axis}[name=plot,     xmin=19, xmax=19.2, xlabel={$[s]$}, ylabel={$Ampiezza$},     ymin=0.651,ymax=0.6535,width=1\textwidth]     \addplot[blue,mark=.] table{50Hz.txt};     \end{axis}     \end{tikzpicture}     \caption{\textit{Oscillazioni a 50Hz}}   \label{fig:50Hz} \end{figure}    \end{document}


Ordinal trends and finding concordant and discordant pairs

A pair is concordant if the subject ranked higher on X also ranks higher on Y. The pair is discordant if the subject ranking higher on X ranks lower on Y. The pair is tied if the subjects have the same classification on X and/or Y.   Say I have a table (e.g., $n_{11}$ is the first cell: $i=1$, $j=1$)  \begin{array}{rrrr}     1   &3   &10    &6  \\     2   &3   &10    &7  \\     1   &6   &14   &12  \\     0   &1    &9   &11 \end{array}  Can you help me to understand how to select the concordant and discordant pairs?  Here's my understanding for concordant: First we select $n_{11}$, then $n_{22}$ is $3$ which is greater than $1$, (higher $Y$ and higher $X$). So we have $1(3+10+7+6+14+12+1+9+11)$, is that right? Then how about $n_{13}$? For $n_{13}$, we have $7$ ($n_{24}$) which is less than $n_{13}$ (lower $Y$). So we don't count this pair right?   I am confused about discordant, how could you select the discordant pairs?


How to change the default fonts in Windows 10

I have read the entries for other OS versions.    Changing the MS Shell Dlg (2) entries in FontSubstitues registry key doesn't seem to work (in Windows 10), or it works in two minor places.  I don't have access to a Windows 95/98/etc. machine, the "earliest" I have is Windows 8.1, so I can't use the Plus directory trick either (directory doesn't exist). For the WindowMetrics registry entry, I seem to have all the *Font keys to be set to the font I want, but that doesn't seem to be doing the trick (on Windows 10). For Windows 8/8.1, there was a program called Windows 8 Font Changer, which worked like a charm, but doesn't seem to on Windows 10 (though it was probably that program run that changed the fonts in the WindowMetrics).   Thanks.   Update: One more method that came out that is perhaps still not the solution: Winaero Tweaker (winaero.com), as it has some issues, the biggest two of which seem to be:   If you have changed the size of text etc. from: "Settings –> Display –> Advanced display settings –> Advanced sizing of text and other items –> set a custom scaling level (not recommended)", the changes do not stick upon a logoff-login or restart. You need to have changed it, if at all, only through "Settings –> Display –> Change the size of text, etc." (which goes up to only a certain percentage, depending on the maximum resolution of your device – 125% on a tablet of mine, which I was able to set to 175% or even 200% with the other, older method that is now apparently listed as not recommended).  Even though it lists a number of items to change the font and size of, not everything gets changed. A typical example of this is the right click menu on the desktop, which still shows the View, Sort By, etc. items in the default font, however much it has a clear 'Change menu font' item.


I'm a little embarrassed to ask this question because it should be easy but it's stumped me for over a week now. The answer will determine how I write some code, so it matters.  According to  the coordinates of an n-sphere in $n$ coordinates is given as  \begin{align} x_1 &= r \cos(\phi_1) \\ x_2 &= r \sin(\phi_1) \cos(\phi_2) \\ x_3 &= r \sin(\phi_1) \sin(\phi_2) \cos(\phi_3) \\     &\vdots\\ x_{n-1} &= r \sin(\phi_1) \cdots \sin(\phi_{n-2}) \cos(\phi_{n-1}) \\ x_n &= r \sin(\phi_1) \cdots \sin(\phi_{n-2}) \sin(\phi_{n-1}) \,. \end{align}  By this formula, the coordinates of an n-sphere in 4 coordinates should be  \begin{align} x_1 &= r \cos(\phi_1) \\ x_2 &= r \sin(\phi_1) \cos(\phi_2) \\ x_3 &= r \sin(\phi_1) \sin(\phi_2) \cos(\phi_3) \\ x_4 &= r \sin(\phi_1) \sin(\phi_2) \sin(\phi_3) \end{align}  Whereas  gives coordinates as (allowing for a change of notation and ordering)  \begin{align} x_1 &= r \cos(\phi_1) \\ x_2 &= r \sin(\phi_1) \cos(\phi_2) \\ x_3 &= r \sin(\phi_1) \sin(\phi_2) \sin(\phi_3) \\ x_4 &= r \sin(\phi_1) \sin(\phi_2) \cos(\phi_3) \end{align}  Which is correct? Note that $x_3$ and $x_4$ are swapped in my version and wolfram's.


I made a method to click on the calendar field and then choose the date, but when I move the parameters, is returning error.  My method  def select_current_date(self, *locator1, *locator2):      self.driver.find_element(*locator1).click()     WebDriverWait(self.driver, AUTOCOMPLETE_TIMEOUT).until(         EC.visibility_of_element_located((By.CSS_SELECTOR, ".ui-icon.ui-icon-circle-triangle-w")))     self.driver.find_element(*locator2).click()     WebDriverWait(self.driver, AUTOCOMPLETE_TIMEOUT).until(         EC.invisibility_of_element_located((By.CSS_SELECTOR, ".ui-datepicker-title")))   Passing the parameters  self.select_current_date(*EventsLocators.RECEIVED, *EventsLocators.CURRENT_DATE)   My error  E     File "/Users/rafael/Desktop/projects/automated_tests/base.py", line 23 E       def select_current_date(self, *locator1, *locator2): E                                                ^ E   SyntaxError: invalid syntax   Any idea?  Cheers!


How to Solve a Coupled Differential Equation?

I came across the set of following coupled equations while studying cycloid motion in Griffiths' Intro to ED   $\ddot{y}=\omega \dot{z}$  $\ddot{z}=\omega (\frac{E}{B}-\dot{y})$  I am at a loss as to how I may approach the problem to solve. Any help is appreciated.


Thread safety with method parameters reference vs value

My understanding about thread safe method parameters is: Parameters passed into a method by value are delivered as copies of the data that was given in the arguments to the method call, so they are unique to that method call and cannot be changed by any other task. Reference parameters, conversely, are susceptible to change by code running in other tasks.  With that said, It is not perfectly clear to me why the following code (without making a local copy of the loop counter) returns the same number in every thread.  static void ExampleFunc(int i) =>             Console.WriteLine("task " + i);   for (int i = 0; i < 10; i++) {     int taskN = i; //local copy instead of i     Task.Run(() => Func(i)); }   The actual output is: task 10 ten times   I get the correct output (task 1 to 10) by passing taskN instead of i.  I expected the same result since I'm passing a type value parameter.


How do not lock/sleep MacBook when you close the laptop lid?

I would like the MacBook not to sleep and or lock when closing the laptop lid. I would like to lock and sleep it only manually. Any ideas on how to do it?


carrier concentration - distance graph of PN junction

i am trying to plot the distance-carrier_concentration graph above with these formulas:   -and-  (p-side: x < -xp , n-side: x > xn) But i could draw only red lines on the graphs with these formulas. How can i or with what formula draw black lines on the graph that majority carrier and space charge region concentration? I am new and i need your help :) Thanks in advance.


Gallery is displaying my movie files from the Movies folder

I usually save movies in the Movies folder of my Galaxy S5 to view them in my VLC app.  Turns out that the movies also appear in the Gallery app. I would really rather have the Gallery app only display images captured by the camera, rather than my movie media files.  Is it possible to limit the Gallery app to simply search the DCIM folder rather than the Movies folder as well? I suspect not - but then, is it possible to isolate my movies so they can only be found by VLC and not Gallery?


Is link building a white hat SEO activity?

Link building is the process of manually building links in any way possible to show the site in question as having more of a value to search engines than it did previously. Therefore it's surely a black-hat SEO activity?    I'm at the stage where I'm trying to promote an online store I'm in the process of launching at the company I work for. I've done most of the initial legwork - domain, server, software, products, on-page SEO, etc. All that's left now is to promote, promote, promote.  I (like many others) would like most of our traffic to come from organic searches because it's both free and passive in many respects (yes, my time isn't free and so on, but let's assume it is for now) so it's a question of ranking well for what I think (based on my keyword research) the terms are that people search for where our site would be the most appropriate. As I said before, all on-page SEO is taken care of, meaning broadly speaking, how well we rank for said terms is down to how many links (or rather, 'how many links of a good quality') I can get pointing to my site and products with appropriate anchor text over our competitors (competitors being not necessarily other online stores, but sites that rank well for those terms regardless of their purpose).  I'm not new to the concepts of SEO, I understand the majority of concepts (it's actually quite simple, though most 'SEO' firms insist it isn't and will throw ridiculous terminology into the mix to boost their 'professional image') and whilst I understand everything, I just can't fathom why anyone would seek to try and build links manually. Link building entails essentially pestering webmasters to link to your site in question, when it's probably the last thing they care about doing for that particular day. Sure there are rare occasions when the site your building links for is genuinely relevant and interesting to the webmaster you're approaching for a link, but in some industries - especially the more 'niche' industries, these kinds of sites are far and few between.  Rather than simply requesting links, many articles now go into the psychology of essentially manipulating people (webmasters, yes, they're people) into linking to their site under the pretences of a false relationship/friendship (sure, you can say it's genuine all you like but you would never have contacted them if you weren't after a link) and spending time on said relationship to the stage where they might link to you... once.  Manual link building seems (well, IS) a very long-winded process with what is essentially very little reward when you consider that you won't continue to gain links if you stop. Major search engines use link counts as an organic method of determining which sites are relevant to what search terms and how they should rank and by building links, you are technically devaluing their efforts to evaluate your site. Surely by this measure, link-building isn't a white-hat process?  I believe the smarter approach (if you were going to approach the webmaster of a site whose audience may find your site interesting and request they link to it) would be simply to send an email with a link asking them to take a look... then if they genuinely found it interesting they might link to it.... and I fear I may have just contradicted myself with my earlier psychology approach.  Should 'link-building' as an activity consist of creating link-worthy exceptional content that is likely to accrue links naturally with age as opposed to the headless-chicken/goose-chase approach many SEO firms seem to undertake?


If energy delivered to the resistor is not the kinetic energy of the electrons then how is it delivered?

In a help session by Walter Lewin he says that the energy delivered to the resistor is not the kinetic energy of the electrons. If not how is energy delivered.  The video link is   and the time into the video is about 4:00 minutes.


What does "?" meaning in /etc/shadow file in RHEL

What does ? meaning in /etc/shadow file in RHEL in second column? myuser:**?**:17968:0:99999:7:::  I could find answer for X, *, !, but not for ?.


Hypothetically speaking, Stock Price won't change in case there is no Volume?

Hypothetically speaking, let's say there is no trading volume during 1 year for a given stock, does that mean the stock price will remain the same regardless of how the company is performing?  Let me emphasize the word "Hypothetically", because I know it is unrealistic. I just would like to know if Supply and Demand is the only rule applied when it comes to stock price.


Accessing bpy.context gives a '_RestrictContext' warning, how to fix this?

I got this error message when I try to enable my addon.  dataBrush = bpy.context.blend_data.brushes  AttributeError:'_RestrictContext' object has no attribute 'blend_data'   Please some help    I am working on an dynamic palette for sculpt brushes


Well, it is not really efficient, but gives some reps (tried two days ago, only 41 reps :-) ).  I have, for example, 50 question where I had accepted answers. And 101 reps, because each accept gives you 2 reps. Then I offer 100 rep bounty (or lose this rep by some other way, e.g. downvotes), unaccept and accept answers again. I am again at 101 reps. Yoyo!


How to recover/reset forgotten Gnome Keyring Password?

I am on Ubuntu and I have forgotten the password for my Gnome Keyring (yes, stupid me, I know). Any way I can get it back? I have already looked at , but it says it's not possible if my home directory is encrypted and unfortunately my home directory is encrypted.


Exclude domains from sends on child business unit level

Working as a Marketing Cloud marketeer in a franchisee setup with 170 child business units I'd like for the franchisee marketeers for every child business unit to be able to always exclude certain domains from being sent to, even though the emails might already exist in their data extensions.  I could possibly do it from the parent level, but to let the franchisees in every business unit know that they own and handle their own data I'd like to teach them how to do this.  So, ie. I'd like to suggest a solution to the franchisee marketeers to automatically exclude emails ending with:    '6url.com', 'aport2000.ru', 'ass.pp.ua', 'axoskate.com', 'backstreet-boys.com', 'bodhi.lawlita.com'.   One way to do this is to have the franchisee marketeers filter the individual child business unit master data extensions for emails ending as described above, and then always exclude this filtered data extension, but this would require the franchisee marketeers to always remember to add the exclusion data extension.  Can anyone suggest a more flexible approach on the child business unit level?  Thank you


How to echo the variable's value containing percent signs?

I want to echo a variable with the %'s.  Ex:  set var=Hello echo %var%   That would obviously result in echoing "Hello", but how can I get it to just echo %var%?


I have a speed-reading program I purchased with uses dotnet2. However, dotnet2 doesn't run on 64 bit wine. How would I install dotnet2?


I'm not sure exactly what it's called, but I would like to draw the line after an integral has been "solved," showing limits of integration, like so:     There is a line with a 9 above and 1 below.


I would like to ship homemade mozzarella. I'm considering purchasing a vacuum packaging system to preserve it for the 2-3 day trip. Is this recommended? If not, are there any alternatives?


I have learn about the final keyword means the refernce can't be changed. And if the keyword can't be reassigned, why can this work?  for(int i =0;i<10;i++){ final TextView tv = new TextView(); }   The tv reference will be assigned for new objects for 10 times.  And its referenced object can still change it's state. If we have an integer  final int a = 3; a++;        // error   it works  final Object obj = new SomeThing(); obj.setAttribute()    And I'm wondering that the keyword final is to describe the  reference or the object it refers to.


Division algorithm for multivariate polynomials?

We know that if $F$ is a field and $f(X)$ a non-zero polynomial in $F[X]$, then for every polynomial $g(X)$ we can find $q(X),r(X)$ such that $$g(X)=f(X)\cdot q(X)+r(X)$$ with $r(X)$ the zero polynomial or $\deg r(X)<\deg f(X)$. My question is: the same algorithm holds for many variables? So can i write $$g(X_1,\ldots,X_n)=f(X_1,\ldots,X_n)\cdot q(X_1,\ldots,X_n)+r(X_1,\ldots,X_n)$$


Let $ Y = \{ (1,1),(0,0\} \subset \mathbb A_k^2$. Find the $ \mathbb I(Y)$.   As if $f(x,y) \in \mathbb I(Y)$ then as $f(0,0)=0$ hence constant term of $f$ is zero and as $f(1,1)=0$ therefore sum of the coefficients of $f(x,y)$ is zero. But how can we describe this set properly?


How can I approach this question in other way without proving that $p(x)=x$ is a unique solution? $p(x^2+1)=(p(x))^2 +1$

If $p(x)$ is polynomial such that $$p(x^2+1)=(p(x))^2 +1$$ and $p(0)=0$ then $p'(0)$ is equal to _____.   Attempt  While looking on it and putting $x=0$ I got $p(1)=1$ and also the equation given had also the similar form (in comparison) of $$y^2+1=(y^2)+1$$. So, I put this polynomial in test and found that it satisfies this as  $p(x^2+1)=x^2+1$ and and $p(x)=x$ and hence it satisfied for every real x and so $p'(0)=1$. But I was not able to progress in the direction of correct solving.  Also, the given related problem is there on this site but, I have not been taught the coefficient determination and hence that answer there is out of my scope for now. But,I think there is this derivative method which I am currently learning and can understand about it.So, I would like to know how to approach this in derivative method and also if there is any other easier way without proving $p(x)$ to be the unique solution.  Also, it may happen that if any other exists,then many persons will get to know about the new method. It will be more helpful to them and me inlcuded.   So, is there any hints or suggestions on this problem?   Thanks for the help!


$\omega_2$ is a not countable union of countable sets without AC

This is an exercise from Jech 3.13  I would like to show that $\omega_2$ is not a countable union of countable sets without AC. I'm given the following hint:   I'm not sure how to define the mapping. We know that there are isomorphisms, $f_n :S_n \to \alpha_n$, so if we define $F: \omega \times \alpha \to \omega_2$ by $F(n, \gamma) = f_n^{-1}(\gamma)$ if $\gamma \in \alpha_n$ and $F(n, \gamma) = 0$ otherwise, does this work? Also, if it works, does it avoid the axiom of choice?


How can I get my texture to show on an Imported file?

So I import a file from turbosquid but it doesn't have the texture. How do I add the texture? I already tried to do texture on it but doesn't work.


A program reads a very large dictionary-style TXT file into a hash. Sometimes, there is a lower case version of a key that is preferable. My solution below is clumsy because it searches twice even if we already know the lc version exists:  if ( exists $hash{ lc $key } ) {    $key = lc $key; } if ( exists $hash{ $key } ) {     # lot of code involving $key } else {     # the key doesn't exist, other code }   Is there a way to avoid two exists tests? If lc $key exists I want to do the identical code to it as in the second if but I need to know which version, lc or not, of $key to use. I'm hoping to condense it to one if-else pair.  Knowing the case of the valid key is important for the rest of the program since it is used to look up information in another hash.


Also show "Add a comment for the author" selection when deleting/voting to delete an answer

I'm aware that this only affects high rep users and mods, but nevertheless it would be nice if the following selection would appear when a user casts a delete vote on an answer.    If I am not mistaken, this only appears when casting delete votes from the review queues. I don't see a reason why this shouldn't also appear when casting a vote directly to the answer, instead of the (java script) alert with "Delete this post?".  Or in other words, the selection should always appear when a user does some kind of 'delete answer' action.


Which wall charger for Beaglebone Green Wireless?

I'm trying to find an appropriate  to power my Beaglebone Green Wireless (BBGW) through Micro-USB port. Wall is 220v 50Hz.  reveals a C Power Management IC (PMIC).   Iout (Max) (A) 1.2    2-A Output Current on Power Path Linear Charger; 700-mA Maximum Charge Current  Confused. How many Amps are enough? (α) 5V, at least 1.2A (β)  5V, at least 2A (γ) 5V, at least 700mA   on Seeed Wiki  on beagleboard.org


sudo apt-get install php5-imagick gives "404 Not Found" error and "E: Failed to fetch ..."

Running:  sudo apt-get install php5-imagick    failed, and produced output including this in the middle:  Get:7 http://us.archive.ubuntu.com/ubuntu/ trusty/main libavahi-common3 amd64 0.6.31-4ubuntu1 [21.7 kB] Get:8 http://us.archive.ubuntu.com/ubuntu/ trusty/main libavahi-client3 amd64 0.6.31-4ubuntu1 [25.1 kB] Err http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main libcups2 amd64 1.7.2-0ubuntu1.1   404  Not Found [IP: 91.189.91.23 80] Get:9 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main libcupsfilters1 amd64 1.0.52-0ubuntu1.2 [74.4 kB] Get:10 http://us.archive.ubuntu.com/ubuntu/ trusty/main libfftw3-double3 amd64 3.3.3-7ubuntu3 [702 kB] Err http://security.ubuntu.com/ubuntu/ trusty-security/main libcups2 amd64 1.7.2-0ubuntu1.1   404  Not Found [IP: 91.189.92.200 80] Err http://security.ubuntu.com/ubuntu/ trusty-security/main libcupsimage2 amd64 1.7.2-0ubuntu1.1   404  Not Found [IP: 91.189.92.200 80] Get:11 http://us.archive.ubuntu.com/ubuntu/ trusty/main libjasper1 amd64 1.900.1-14ubuntu3 [129 kB] Get:12 http://us.archive.ubuntu.com/ubuntu/ trusty/main liblcms2-2 amd64 2.5-0ubuntu4 [132 kB]   and this at the end (referring to the same errors):  E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/c/cups/libcups2_1.7.2-0ubuntu1.1_amd64.deb  404  Not Found [IP: 91.189.92.200 80] E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/c/cups/libcupsimage2_1.7.2-0ubuntu1.1_amd64.deb  404  Not Found [IP: 91.189.92.200 80] E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?


Where are static variables stored in C and C++?

In what segment (.BSS, .DATA, other) of an executable file are static variables stored so that they don't have name collision? For example:   foo.c:                         bar.c: static int foo = 1;            static int foo = 10; void fooTest() {               void barTest() {   static int bar = 2;            static int bar = 20;   foo++;                         foo++;   bar++;                         bar++;   printf("%d,%d", foo, bar);     printf("%d, %d", foo, bar); }                              }   If I compile both files and link it to a main that calls fooTest() and barTest repeatedly, the printf statements increment independently.  Makes sense since the foo and bar variables are local to the translation unit.  But where is the storage allocated?  To be clear, the assumption is that you have a toolchain that would output a file in ELF format.  Thus, I believe that there has to be some space reserved in the executable file for those static variables. For discussion purposes, lets assume we use the GCC toolchain.


Minimum amount of days travel insurance policy should cover for Schengen visa?

My father in law is travelling to France, for 4 days, (01/07-04/07). Is there a minimum duration for which the travel insurance needed to apply for a Schengen visa must be valid? In other words, can his travel insurance cover just the duration of the trip, or should it last longer?


Evaluate $\sum_{n,k} \binom{n}{k}^{-1} $

Evaluate $$\sum_{n,k}  \frac{1}{\binom{n}{k}}, $$ where the summation ranges over all positive integers $n,k$ with $1<k<n-1$.  Thouhgts: We are trying to evaluate $$\sum_{n=4}^{\infty} \sum_{k=2}^{n-2} \binom{n}{k}^{-1}$$ We may try to find a closed form of the inner summation which is of the form : $$ \frac{1}{ {n \choose 2} } +  \frac{1}{{n \choose 3} }+ \dotsb + \frac{1}{{n \choose n-2} }.   $$ Notice that we may write $\frac{1}{ {n \choose 2} } = \frac{2! }{n(n-1)}$ and if keep doing the same for the other terms we obtain the following: $$ \frac{ (n-2)! + (n-3)! (n-(n-2)) + (n-4)!(n-(n-2))(n-(n-3)) + \dotsb + 2! (n-3)! }{n!}, $$ which equals $$ \frac{ (n-2)! + 2!(n-3)! + 3! (n-4)! + \dotsb + (n-3)! 2! }{n!} $$ and so this equals: $$ \frac{1}{n(n-1)} + \frac{2}{n(n-1)(n-2)} + \dfrac{6}{n(n-1)(n-2)} + \dotsb + \dfrac{2}{n(n-1)(n-2) }. $$ But half of this terms are identical. Therefore, we are trying to sum up series of the form $$\sum_{n \geq k} \frac{1}{(n-1)(n-2)(n-3)\dotso(n-k)} ,$$ which can be done by a telescoping trick, but it seems very formidable. Am I approaching this problem the right way? Any hints/suggestions?


I'm making vinegar by adding all natural apple juice to all natural apple cider vinegar with mother.  A scoby formed on top.  Mold is now growing on top of the scoby.  It's stuck on top of the scoby, not floating on top.  I can't easily scrape it off without scraping the scoby.  Should I leave this mold on top, will it affect the vinegar?


how do I find my username in kali linux?

I installed kali and the next day after coming to work I forgot the username, I was able to find answers on how to change the password but not to get username info.


I've just watched the anime, in there Blast doesnt appear, but I believe he was mentioned when the heros gathered to fight the aliens. Supposedly he's the #1 hero of the hero association but he never appears. Does he appear in the One Punch Manga or at least in the webseries?


I've run into some strange behaviour today:  #!/bin/bash set -ex export a=$(cat foo) echo "It's a living thing" b=$(cat foo) echo "This won't make it"   This won't stop on cat foo even though foo does not exist. But without the export, it fails. Why?


Why index REBUILD does not reduce index fragmentation?

I used ALTER INDEX REBUILD to remove index fragmentation. In some cases, REBUILD does not seem to remove this fragmentation. What are the reasons why REBUILD does not remove fragmentation?


Is there a single word for a "friend of a friend"?

I am looking for a word that I could use instead of "friend of a friend". On certain occasions, it happens that you may want to talk about a friend of a friend with someone else.   In such cases how would you refer to this friend?


I know the basic technical stuff, what now?

I know the basic concepts:   aperture, shutter speed, iso focal length and DOF I know what the rule of  thirds is I have made some little jobs using Photoshop (most of them by intuition).   I want to make more professional-looking photos (most of all I'm interested in landscape and product photos). What should I learn? I was thinking two main topics should be:   Lighting Color correction/enhancement in Photoshop   Any better/further subject I should consider? Is there a good book to step from "amateur" to "enthusiast"?


Multiple images on page, but google to only crawl certain ones

Say I have a page with a main image of a product at the top and several related product images at bottom. When I google the main product, the google search results also show up the main product image and also the related product images, claiming to be the main product. Is there a way I can stop google from crawling certain images on the page, by adding a tag to the images I don't want google to crawl, like a no-crawl?


What if we suppose continuum hypothesis is false?

Something I have puzzled about is the demonstrated reality continuum hypothesis can be neither proved nor disproved from Zermel-Fraenkel Set Theory. I'm not sure if my question makes sense, but I ask "what would be the consequences of adding the statement 'continuum hypothesis is false' to the axioms?"   Would that mean anything .... i.e. are there interpretable statements that could then be proved or disproved from the new axiom set?  For example if there is an Aleph number greater $\aleph_0$ ($= \beth_0 =$ cardinality of natural numbers) but less than $\beth_1$ (= Cardinality of Reals) might there be infinitely many? If so might that be provable (or possibly not)?


The study was carried out up to visit 11 under the name of X1,   whereas all later visits were carried out under a different name,   X2.   In the above sentence, does V11 belong to X1 or X2? I want the sentence to mean that V11 was included in X1, how should the sentence be then?


First step to get going with passive income?

I want to start generating additional income streams and what I've heard of most is "passive income"! I googled a lot, but I am not quite sure what option fits a beginner best... Any advice?


My laptop has 1 GB Nvidia graphics card.   When i used windows i needed to install graphics card.   Now i am using ubuntu 14.04 with windows 8.1 as dual boot.  Do i need install a graphics driver for ubuntu? if yes how?


What do you call a person who loves to read?


How do you calculate centroids in QGIS 3.0? In previous versions, there was an easily accessible tool in the vector geometry toolbar, but it is gone. I've seen ways to do it with Python on Stack Exchange but I am not that good with Python.  I've tried a few Python plugins to no avail. I've repeatedly got the response "Couldn't load plugin 'realcentroid' due to an error when calling its classFactory() method", which I do not understand.


I am using Ubuntu Minimal + LXDE. I am wondering how can I auto-mount a partition (internal) on boot automatically. Currently I do something like   mount /dev/sda3 /media/works   But I want it to be permanent. Also I have GParted, but the Partition > UnMount is greyed out (yes, unmount, even though I haven't mounted it)


I can say in Spanish,      Yo jugaba al tenis cuando tenía 8 años,   which means     I used to play tennis when I was 8 years old.   I could also ask,     ¿Jugabas tú al tenis cuando tenías 8 años?   whose English counterpart is     Did you play tennis when you were 8 years old?   Sometimes I get stuck, though, since it's hard to ask     Did you use to play tennis ...   Is there a real way to ask a question in the imperfect using the "used to" form of the imperfect?


Sum of products of binomial coefficients: $ \sum_{l=0}^{n-j} \binom{M-1+l}{l} \binom{n-M-l}{n-j-l} = \binom{n}{j} $

In a proof I've come across the following identity:     $$ \sum_{l=0}^{n-j} \binom{M-1+l}{l} \binom{n-M-l}{n-j-l} = \binom{n}{j} $$   I see that it's right, when plugging in numbers, but I don't see the algebraic or combinatorial proof behind it. Can anyone help me with that?


Is there a nice way to perform calculations within a quotient ring? for instance, an exercise I had was to show $\mathbb{Z}[X]/(X^2+1) \cong \mathbb{Z}[i]$, but this got me thinking; If I didn't know this, how could I calculate in $\mathbb{Z}[X]/(X^2+1)$ easily?  (and of course any other general quotient ring)?


creating a simple vim syntax highlighting

i have a simple sort of a database file which consists only of entries in the following format     variable=value   i want to create a simple vim syntax highlighting for it and set it for specific file extension  for instance, variable part could be light blue, and value part light red  i googled it and came across things such as $vimruntime\syntax\, syntax set=, syntax match, and hi keywords, but couldn't set it up myself eventually  so i want a very simple vim code snippet that would realize it by matching the left and right hand sides and coloring them separately


I'm writing a paper that has citations in it. I use Jabref to organize the citations. Where I run Texmaker I get the following error:  What weird is that when I run this on a different computer, everything works fine (so I assume that my .bib file is ok). Is there any solution for this? Saw few questions about this subject however without any answer. Thank you


Show that the sum of the oscilations is less or equal to $f(b)-f(a)$

I want to show the following:     Let $ f:[a,b]\to \mathbb{R}$ be an increasing function.If $ x_1,\ldots,x_k\in[a,b]$   are different, show that $$\displaystyle\sum_{i=1}^k o(f,x_i) < f(b) - f(a).$$    My attempt:  Since $f$ is increasing we have that:  $$f(a)<f(x_1)<f(x_2)< \ldots <f(b).$$  Therefore for each $i=1, \ldots, k$ and for all $\delta$,  $$M(f,x_i, \delta)< f(b) \quad \text{and} \quad m(f,x_i, \delta)> f(a)$$  and then in each point:  $$o(f,x_i) < f(b) - f(a).$$  The thing is that I don't know how to proceed with the sum. Can someone help me to complete this proof?


Prove two sets have same Cardinality by writing down bijection

a. Prove that the interval $A = [1,3]$ has the same cardinality as $B = [1,5]$ by writing down a bijection from $A \to B$. Don't prove it is a bijection.  b. Consider the following infinite set: $A = {1, \frac{1}{2},  \frac{1}{3},  \frac{1}{4},..., \frac{1}{n}}$,     Prove the set $A$ has the same cardinality as the integers by writing down a     .  bijection from $A$ onto $Z$.  I don't know how to find a function that is a bijection from one set to another. Can anyone help by explaining the thought process behind it, I've been having trouble with these types of problems? Thanks.


Class jquery hover function are  working after scroll.   $(document).ready(function() {     $('img').hover(function(){         alert('hello');     },function(){         alert('hello not');     }); });   on hovering images loaded on first site are showing alert hello but after scroll images load(lazzy loading). On hovering those images alert is not showing.