What happens with "Does this answer your question?" - Yes

Question When one/more users suggest another post answers your question (and there is a banner at the top of the page asking if question title answers your question? Yes/No), what physically happens to your question/on the site if you select Yes? (For example: is it immediately deleted, is it marked as duplicate, can people still provide answers, etc?)  Context  In my case, the suggested post partly answers / relates to my question (about 50%) - so I am more happy for my question to be linked to the suggested answer, if that's the outcome(?) (assuming my question isn't then deleted/hidden on the site) However, as the post question only partly covers my question (and in addition, several users have provided very helpful and detailed answers to my question), I definitely would not want my question (their contributions) to be deleted, if that's the outcome(?)   Related questions Please note (and for users who wish to read/learn more), there are several answers on the related topic of 'duplicate questions':   Summary: This is a feature request based on a issue caused by a much older version of SE. It is useful for context, but does not answer the above question specifically. Note (and de-dupe defence): The lead answer is 6 years old and the "new/updated" UI it shows is out-of-date.  Summary: This is a discussion about making duplicates more clear. Note (and de-dupe defence): Similar to the above, the lead answer references an old version of SE and the website has since changed. There is one answer that recommends [Change the text on the first button from "That solved my problem!" to "Yes, my question is a duplicate."] but is low-scoring (5 vs. 150+ on lead) and is also from 6+ years ago - so unclear if this is what happens or not.  I believe this question is warranted and my intention is to clarify how SE works (in the context of "Does this answer your question?"), and help remove any doubt/confusion for users. (The alternative being for users to continue to read about how SE used to work half a decade ago).


Calculating the tipping point of a lamp post

So I'm designing an outdoor lamp post and trying to calculate whether it will withstand the heavy winds at the worst case scenario. Here are the parameters and what I've done so far:  The lamp post is 2.8m tall with the base radius of 0.9m. Assuming that the post itself, m1=50kg and the base, m2=30kg, the center of mass stands at 1m above the base. I have chosen the wind speed that it needs to withstand as 20m/s which corresponds to Beaufort Scale 8.  Through the wind load formula, F=A * P * Cd, I found out that the force in which the wind exerts on the body is roughly 400N.  Assuming that 400N of force is applied to the lamp post sideways at the tip of it, how can I calculate whether it will tip over or not? If not, how can I figure out how much I need to increase the weight of the base to withstand the wind forces? Does torque equation help? Any answers that could point me in the right direction are much appreciated.


Prove $A = (A \setminus B) \cup (A \cap B)$  Logically, this is clearly true. I can explain why: start with $A$, remove all elements in $B$ and then add in any elements in both $A$ and $B$, which restores you back to $A$. That's an explanation, but AFAIK, it's not a proof in the formal proof sense.  I submitted a proof by a truth table which considers the four possible scenarios where an element is in/not in $A$/$B$. My professor asked me to redo the proof without a truth table.  My question is what mechanisms and strategies can I use to prove this in a acceptable formal proof sense?


What is a "double date"?  Why do I sometimes see dates written as January 13, 1718/1719?  See also:


Why do we not reinvent the journal system?

I am very surprised that I could not find any similar question here.  It seems to me that researchers from all universities are willing to write papers about their research for free and hand them into a journal to gain reputation. On the other hand, some other researcher do voluntary check the paper in order to examine if the paper is acceptable for the journal. Therefore, the main work is done by researches.     The remaining work for the journal is to offer a platform where researchers can communicate and making sure that the reviewer is selected anonymous and to bundle many articles to a journal.   Now everyone has to pay a huge amounts for the papers, they are not accessible for free to the general public, even though that most researchers are financed by taxes and only the journal is making profit.  Now I wonder, should it not be possible to create a network page for researchers which contains methods to imitate the review process of a paper? So that all papers can be downloaded at the website for free. I guess most researchers would be very happy if everyone could read their work. Also the money that is spend on journals by universities could be spend to this huge network page instead in order to keep it running.


Prove there exist $a, b$ coprime such that $a|r, b|s$ and $lcm(r,s)=ab$ with $r, s\in\Bbb{N}$

I just made a proof and I would like to verify it. Statement  If $r, s \in\Bbb{N} \implies \exists$ $a,b \in\Bbb{Z}$ coprime such that $a|r, b|s$ and $lcm(r,s)=ab$.  My proof  If $r$ and $s$ are coprime, with $a=r$ and $b=s$ we have:  $a$ and $b$ are coprime integers $a|r$ $b|s$ $lcm(r,s)=rs=ab$  If $r$ and $s$ are not coprime, since both are greater than $1$ (otherwise they would be coprime) we have that $gcd(r,s)=d\ne 1$. We can express $r=dq$, $s=dq'$ with $q$ and $q'$ coprime integers. Using the relationship between $lcm$ and $gcd$ we have that $lcm(r,s)=\frac{|rs|}{gcd(r,s)} \implies lcm(r,s)=\frac{dqdq'}{d}=dqq'$. If $q$ and $d$ are coprime, with $a=q$ and $b=dq'$ we have:  $a$ and $b$ are coprime integers $a|r$ since $q|dq$ $b|s$ since $q'd|q'd$ $lcm(r,s)=dqq'=ab$  The following part is not correct  If $q$ and $d$ are not coprime, let be $gcd(q,d)=l$. With $a=ql$ and $b=\frac{dq'}{l}$ we have:  $a$ and $b$ are coprime integers $a|r$ since $ql|dq$ $b|s$ since $\frac{q'd}{l}|q'd$ $lcm(r,s)=dqq'=\frac{qlq'd}{l}=ab$   This is the corrected (I think) version of the last part  If $q$ and $d$ are not coprime: let be $q = \prod_i p_i^{q_i}$ and $d = \prod_i p_i^{d_i}$ the prime factorization of $q$ and $d$ respectively. We define $D=\{i:q_i>0,d_i>0\}$. Let $l = \prod_{i\in D} p_i^{d_i}$ Then with $a=ql$ and $b=\frac{dq'}{l}$ we have:  $a$ and $b$ are coprime integers by construction $a|r$ since $ql|dq$ $b|s$ since $\frac{q'd}{l}|q'd$ $lcm(r,s)=dqq'=\frac{qlq'd}{l}=ab$   $\square$  I wanted to know if my proof is ok and since this exercise belongs to a 'groups - primitive roots' sheet of exercises, if there is another proof related with those concepts.


Vague Compiler error "cannot find symbol", but doesn't specify which symbol

*This question is not a duplicate of "non-static method cannot be referenced from a static context?", and it covers a different error message, which is "Cannot find symbol".  I'm having an issue with JCreator showing the build error error: cannot find symbol, while not specifying what symbol is found.  code:  import javax.swing.*; import java.awt.*; import java.awt.event.*; public class FanTest extends JFrame {     public FanTest()     {         setLayout(new GridBagLayout());     //more stuff here     }     public void addCompsToGui(Container pane)     {         pane.setLayout(new GridBagLayout());         GridBagConstraints c = new GridBagConstraints();      //more stuff here     }     public static void main(String[] args)     {         FanTest gui = new FanTest();         gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         gui.setSize(600,600);         gui.setTitle("Test Console for Fan");         addCompstoGui(gui.getContentPane()); // error pointing to this line         gui.setVisible(true);     } }   This is homework, and I'm only looking for help with the one error and it's resolution


Does any uncountable set contain two disjoint uncountable sets?

Is it true that for any uncountable $S$, there exits two uncountable subsets $S_1,S_2 \subseteq S$ with $S_1 \cap S_2 = \emptyset$?   I can find no counter example, but no proof either.  I am aware of similar questions regarding the partition of uncountable subsets of the real line, and there are many examples of disjoints uncountable subsets of $\mathbb{R}$, say $R_1,R_2$.   It is not clear to me however whether this extends to any uncountable set. For uncountable sets $S$ with $S \succeq_{card} \mathbb{R}$, there exists an injection $f : \mathbb{R} \rightarrow S$ and choosing $S_1,S_2$ with $S_i = \{s\in S~|~ s = f(r_i) $ for some $ r_i \in R_i\}$, works.   But from what I understood of the continuum hypothesis, there might exist an uncountable sets $H$ with $\mathbb{R} \succeq_{card} H$. So using the above argument, one cannot infer that the property holds for every uncountable sets from observing that it holds for $\mathbb{R}$. Is this right? Are there other ways to prove or disprove the assertion?


Placing $9$ black and $9$ white rooks on $ 6\times6$ board without any attacks between different colours

In how many ways can $9$ black and $9$ white rooks be placed on a $6 × 6$ chess board, so that no white rook can capture a black one? A rook can capture another piece if it is in the same rank (row) or the same file (column) as the other piece, with no other pieces between the two?  I was thinking of a $6×6$ matrix, but that option doesn't seem to help?


How many questions are asked daily on Stack Overflow?

I really like the idea of Stack Overflow, but I wonder if anyone knows (maybe the site admins, if they're reading) how many new questions are being asked each day.  Is it around 5,000? 200,000? A million?


Ubuntu 16.04 WiFi not working after update

I'm using following wifi hardware (08:00.0 Network controller [0280]: Broadcom Limited BCM43142 802.11b/g/n [14e4:4365] (rev 01))  network UNCLAIMED        description: Network controller        product: BCM43142 802.11b/g/n        vendor: Broadcom Limited        physical id: 0        bus info: pci@0000:08:00.0        version: 01        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: memory:c1500000-c1507fff   This has just stopped working after recent update by Ubuntu which made me auto remove few files as they weren't needed.  I have tried following links none worked:    Kindly help  Sicerely


Is there a way to test code coverage within visual studio if I'm using MSTest? Or do I have to buy NCover?   Is the NCover Enterprise worth the money or are the old betas good enough if Microsoft doesn't provide built in tools to do code coverage?  EDIT: Description of VS Products and which ones include code coverage   TestDriven.NET () can be used if your VS version doesn't support it.


Configure tab-switch hotkey in gnome-terminal

I used to use Alt+number to switch between gnome-terminal tabs. In my recent 19.10 installation, this does not work. When I press Alt+1, instead of switching tab, the command line shows this: (arg: 1)   and if I press Alt+2, it becomes: (arg: 12)   I checked the options in gnome-terminal, it is set to use Alt+number to switch between tabs. I would like to know which application is hijacking the hotkey, and how to fix it. PS. I do NOT want to use Ctrl+PgUp/PgDn for this. Thanks.


What's the best way to secure a GET request or are there any, safer alternatives?    I'm using a couple of GET requests in my website to generate webpages dynamically and to delete records based on ID.  The last one worries me a bit, because people could just change the URL to whatever file they want to delete.  To have access to the delete-file they do need to login and have certain permissions, which will throw an error if they don't have sufficient permissions.    I came across , stating that you should use themysqli_real_escape_string function to make it at least more secure.  I also read about validation being really important, so I was thinking about checking whether the ID is an actual integer or not.   stating that hiding the request in the URL is basically useless, since the request will always be a part of the URL.    This is my delete-file, it uses two statements, one deletes the actual post, and the other one deletes the associated images with that post.  include('./utils/auth.php');  require('./utils/db.php');  $stmt_1 = $connect->prepare('DELETE FROM `dias` WHERE diaserie_id = ?');  if($stmt_1) {     $id = $_GET['id'];     $stmt_1->bind_param('i', $id);     if($stmt_1->execute()) {         // Als de afbeeldingen uit de database zijn, verwijder dan ook de serie zelf         $stmt_2 = $connect->prepare('DELETE FROM `diaseries` WHERE diaserie_id = ?');         if($stmt_2) {             $stmt_2->bind_param('i', $id);             if($stmt_2->execute()) {                 echo "Both the files and post have been deleted.";             } else {                 echo "The files have been deleted, the post iself could not be deleted.";             }         }     } else {         echo "Files and post could not be deleted.";     } }


I want to create the following image in TikZ/PGFplots.  Questions such as  are a good start, but I am not clear how to modify them to include row labels. A straightforward addition of rows, such as below, only gives an error.   \documentclass{standalone} \usepackage{colortbl} \usepackage{pgfplots} \usepackage{pgfplotstable}  \pgfplotstableset{     /color cells/min/.initial=0,     /color cells/max/.initial=1000,     /color cells/textcolor/.initial=,     %     % Usage: 'color cells={min=<value which is mapped to lowest color>,      %   max = <value which is mapped to largest>}     color cells/.code={%         \pgfqkeys{/color cells}{#1}%         \pgfkeysalso{%             postproc cell content/.code={%                 %                 \begingroup                 %                 % acquire the value before any number printer changed                 % it:                 \pgfkeysgetvalue{/pgfplots/table/@preprocessed cell content}\value                 \ifx\value\empty                     \endgroup                 \else                 \pgfmathfloatparsenumber{\value}%                 \pgfmathfloattofixed{\pgfmathresult}%                 \let\value=\pgfmathresult                 %                 % map that value:                 \pgfplotscolormapaccess                     [\pgfkeysvalueof{/color cells/min}:\pgfkeysvalueof{/color cells/max}]                     {\value}                     {\pgfkeysvalueof{/pgfplots/colormap name}}%                 % now, \pgfmathresult contains {<R>,<G>,<B>}                 %                  % acquire the value AFTER any preprocessor or                 % typesetter (like number printer) worked on it:                 \pgfkeysgetvalue{/pgfplots/table/@cell content}\typesetvalue                 \pgfkeysgetvalue{/color cells/textcolor}\textcolorvalue                 %                 % tex-expansion control                 % see https://tex.stackexchange.com/questions/12668/where-do-i-start-latex-programming/27589#27589                 \toks0=\expandafter{\typesetvalue}%                 \xdef\temp{%                     \noexpand\pgfkeysalso{%                         @cell content={%                             \noexpand\cellcolor[rgb]{\pgfmathresult}%                             \noexpand\definecolor{mapped color}{rgb}{\pgfmathresult}%                             \ifx\textcolorvalue\empty                             \else                                 \noexpand\color{\textcolorvalue}%                             \fi                             \the\toks0 %                         }%                     }%                 }%                 \endgroup                 \temp                 \fi             }%         }%     } }  \begin{document}      \pgfplotstabletypeset[     color cells={min=0,max=0.8,textcolor=-mapped color!80!black},     /pgfplots/colormap/greenyellow,     /pgf/number format/sci,row sep=crcr, ]{     \phantom{A} a   b   c   d\\     a 5e-1    8e-1    4.4e-2  1e-3  \\        b 0.050   -0.300  -0.200  -0.100 \\     c -0.20   0.1 0.100   0.200\\     d 0.005   0.300   0.40    0.800\\     d 0.8 0.030   0.050   0.70\\ } \end{document}


Let $(G,*)$ be a finite semigroup with identity. Prove that $G$ is a group iff $G$ has only one element $a$ such that $a^2=a$. For the right direction, since $G$ is a group with identity, then there exists $a=e_G$ i.e. $a^2 = a$. Isn't it? For the left direction, what should I do?


GET in PHP does not decode the variable name correctly after a SUBMIT using JS

I need to perform some very specific checks on a form, so I call a JS function on the submit and, if everything is ok, I call the "submit" method of that form using JS.  <form id="booking" action="booking.php" method="get">     <input name="Name *" type="text">     <input onclick="if (allOk()) document.forms['booking'].submit();             return false;" type="submit" value="booknow"> </form>   This is the generated URL  booking.php?Name+*=marco   but...  print_r($_GET);  ...  Array ( [Name_*] => marco )   I need to know how can I get the original name of the element, Name * in this particular case, from the Name_*  Why is there an underscore, where there should be a space?  I tried urldecode, rawurldecode, and some others but it is still not working. Is it because you cannot use spaces in the GET elements? Will it be safe to simply replace each underscore with a space?  I never had any problems encoding/decoding GET/POST values, but it looks like I have problems when the field name has to be encoded/decoded too.  PS: I know I should use POST, but it has the exact same problem, and I switched back to GET to debug it faster.


What is the difference between using theme_table() and theme('table', array())?

I am using following code for theming..  theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => array('class' => 'view-all-frame')));   is the above format right? Can 'attributes' be written above inside array? Can I use theme_table() instead of theme()?   theme_table(array('header' => $header, 'rows' => $rows, 'attributes' => array('class' => 'view-all-frame')));   If they are same then does it affect the execution or anything related to it?  Similarly for theme('item_list', array()) and theme_item_list();


"When I am in Berlin" or "when I will be in Berlin"?

Which sentence is correct?    Maybe we could visit the Bundestag when I am in Berlin.  Maybe we could visit the Bundestag when I will be in Berlin.    Thanks for help!


quick way to add chrome (or internet) shortcuts to home screens

On  the iphone, under the Safari settings, there was an option ADD TO HOME SCREEN.  that gets quite handy to have direct bookmarks launchable from a single tap on the icon.  How do you do that in the android world?   I got a note 3 & I'm dying to get this functionality in.


Why source (or dot command) doesn't require the file to be executable

From running help . or help source     Execute commands from a file in the current shell.      Read and execute commands from FILENAME in the current shell.  The       entries in $PATH are used to find the directory containing FILENAME.   From my point of view, it seems like the dot command (or the source command) is simply running a shell script in the current shell context (instead of spawning another shell).  Question: why doesn't . (or source) requires the file to be executable like when you run a normal script?


sge get script location inside the script

Im writing a script to be run through qsub in a sge cluster.   I have several executables that I need to call in the script and all of them are in the same location (the same as the script itself). So Im wondering How can I get the location of the script Im executing.  I have an automatic build system and it is just not right to hard code this location. The code should be something like  #!/bin/bash   #$ -S /bin/bash   #$ -V   #$ -cwd #$ -N "Job"    exec="/path/to/this/script/"execNameJob   $exec   I tryed a couple of things and they didn't work and people marked as duplicate. None of the previous solutions worked. Im running my script using  qsub -o console.out /tmp/qsubScript/qsubScript.sh. What I want to get is the /tmp/qsubScript/ path in the script  SOURCE="${BASH_SOURCE[0]}" while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink   DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"   SOURCE="$(readlink "$SOURCE")"   [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE" # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located done DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"  echo " Directory SOURCE: $DIR" echo " BaseDir 0: " $0 echo " SGE_ROOT: $SGE_ROOT" echo " SGE_JOB_SPOOL_DIR: $SGE_JOB_SPOOL_DIR"   the output is:  Directory SOURCE: /opt/gridengine/default/spool/compute-2-8/job_scripts  BaseDir 0:  /opt/gridengine/default/spool/compute-2-8/job_scripts/9534  SGE_ROOT: /opt/gridengine  SGE_JOB_SPOOL_DIR: /opt/gridengine/default/spool/compute-2-8/active_jobs/9534.1    The main problem is that the sge implementation copy my script into a job_script, so I loose the reference to the original script.


how to place a non-floating figure using x,y page coordinates?

I wish to know if is it possible to place a non-floating figure using x,y page coordinates? Also above other figure or text   For example. The yellow rectangle is the area where I wish to place my figure


Touch ID when “Sublime Text wants to make changes”

I figured out how to use Touch ID for .  But when I edit /etc/hosts with my Sublime Text, I still get this window:    How can I use Touch ID for messages like this? 😀


Proving $\log(x)$ not uniformly continuous

I am trying to solve problem and I keep running into a different proof. I am trying to prove $\log(x)$ not uniformly continuous (0,1) yet I keep running into the proof for uniform continuity with $\ln(x)$ on (0,1). I am challenged and would appreciate some help. please and thank you.


Counting length of Objects in JavaScript

I have an object, that will have variable number of other objects in it. In other words I have a container Object, that has other children object in it. Children do have their own properties.  I need to find a number of children objects in it, for that I found two ways of doing it. I am interested which one is the best practice way.  First way:  var numberOfChildren = Object.keys(parentObject).length;   Second way:  var tempP = parentObject             var count = 0;             for (var p in tempP) {                 if (tempP.hasOwnProperty(p)) {                     count++;                 }                 alert(count)             }   Third Way:  var sizeofChildren= _.size(parentObject);   I have added the third way as well Ideas?


prove that the inner product of path and velocity is zero

let $I \subseteq \mathbb{R}$ be an open interval. A function $\gamma : I \rightarrow \mathbb{R}^m $ is called a path and we write $\gamma (t)=(\gamma^{1}(t),\ldots,\gamma^{m}(t)) \in \mathbb{R}^m$. If all m components are differentiable functions from $I \ \mbox{to} \ \mathbb{R}^m$,then the path is a differentiable path. Then for every $t \in I$, we consider $\gamma'(t)=((\gamma^{1})'(t),\ldots,(\gamma^{m})'(t)) \in \mathbb{R}^m$ which is called the velocity vector of $\gamma$ at t.  Question: if $\gamma:I \rightarrow \mathbb{R}^m$ is a differentiable path and $||\gamma(t)||=1, \ \forall t \in I$. We fix a point $t_0 \in I$ and denote $\gamma(t_0):=\vec{a},\gamma'(t_0):=\vec{q}$ Prove that $$<\vec{a},\vec{q}>=0$$  My method is to use $0\leq |<\vec{a},\vec{q}>| \leq ||\vec{a}|| ||\vec{q}||=||\vec{q}||$, then by squeeze theorem, we can have the inner product equals zero. However, as you see, my method does not work.


System installation is stalled on Compaq Presario R3000

I'm attempting to install Ubuntu 14.04.1 (the only version I have handy) onto my old Compaq Presario R3000 (this Ubuntu was recommended for this computer). The installation has stalled at about 60% and hasn't moved in an hour.  The message at the bottom says: Configuring bcmwl-kernal-source (i386).  I have no experience with Ubuntu (or with Linux, for that matter), coming from a strictly-Windows background). Can anyone offer some advice?


If you have a series of subfolders (like from a to z) and want to run a command on each one of them (like rm *.pdf or ls *.pdf), how do you do that? The "manual" approach would be cd a, rm *.pdf, or ls *.pdf, cd .., cd b, ... That seems too complicated, so I believe there must be an easier approach.


Let a,b be integers. Then $3 | a^2 + b^2$ if and only if 3 | a and 3 | b

I need to prove this using modular arithmetic but I'm a little stuck. Could I get some pointers? Thank you.  Let $a,b$ be integers. Then $3 | a^2 + b^2$ if and only if $3 | a$ and $3 | b$


I have been wandering around some SEO sites this evening and have been seeing this term linkbaiting. The word bait kind of makes it not sound so great.  What exactly is linkbaiting and how does it differ from article marketing? From the gist of some of these descriptions I'm seeing, this is something fairly new, but it seems almost identical to article marketing. What am I missing?


How to include advisor’s name onto research paper

My advisor helped me with my year-long research project. Should I list him as an author or under ”contributor” and do you have a link to a format for how I should do this?


From this calculation (), two protons seperated by the distance of one atom feel the electromagnetic force repelling them 1.239*10^36 stronger than the gravitational force attracting them.  This means that for gravity to be able to bring hydrogen atoms together to make stars, their overall charge must have to be PERFECTLY neutral. Is this level of symmetry surprising? Does it show protons and electrons were cut from the same cloth?


How can I prove: if $p $ is prime and $n>1$, then $ p^{\frac1n} $ is irrational?


How many different sizes of infinity are there?

It's pretty straightforward to say that there is an infinite number of different sizes of infinity, but then I thought, "What size of infinity is that?"  My thoughts are that the number of unique cardinalities is equivalent to the number of real numbers, based on the fact that the cardinalities can always be ordered by increasing size. I don't really know how to prove this, though. It's mostly based on intuition, which isn't very reliable when talking about uncountably infinite sets.  I originally asked a somewhat related  at a different (and not math-oriented) forum, and the users there told me that it is not possible to talk about the number of cardinalities without talking about the set of all sets, which forms a paradox. If a set were to contain all of the different sizes of infinity, it would have to contain its own power set, which isn't possible.  However, I'm not completely convinced that it is not possible to talk about a set of all of the cardinalities. Sure, a cardinality represents a size of infinity, but I think that it should be possible to have a set of the cardinalities without having the set actually contain the various infinities. Would this avoid the above paradox?  So, is it possible to measure the number of different sizes of infinity, and what would that size be?


Stop Windows 7 Explorer from automatically expanding folders

Windows 7 Explorer can be opened in any folder from the command line.  But, it automatically expands (on the left nav panel) the Favorites, Desktop, and [Username] folders.  This makes it hard to see what's what in the nav panel.  How can I tell Windows 7 Explorer to collapse those folders by default, until I open them? I only want the selected folder expanded.


Please advise me my excel files are not changing like previous version i had, now I am pressing alt + two times tab in excel for go back to my previous windows i tried my best to reach out from this but i found no solution regarding this matter , kindly check and give me any solution if available.


Expression "N-fold" eg the stock value went up 3-fold

Where does the expression x-fold come from? And is its current usage the same as when it originated?   For example, if you fold a piece of paper n times, the thickness is not n times the original times n, but 2 to the power of n. So 5 folds means the thickness is actually multiplied by 32, not 5. Yet saying something increases 5-fold means it's 5 times greater.


Can I uninstall Windows 8.1 from my current computer and put it onto a new motherboard?

I recently started looking into parts to build a new PC from scratch and was wondering about the operating system. I bought a full version of Windows 8.1 and installed it onto my current computer using a 64-bit disk. I was wondering if I would be able to deactivate Windows 8.1 on my current computer and install it onto a new motherboard altogether or if that is not possible and I would need to buy a whole new operating system.


How to make mksh for loop go from 1 to N

So I've tried to do this  for x in {1..7000} do    echo $x done   The output is {1..7000}   I've also learned that the C-style for loop doesn't work in mksh  I've done a bit of googling but mostly there is information about ksh, not mksh  So what is the correct way to iterate through a range in mksh ?  NOTE: I am more interested in proper way to create iterations and c-like behavior rather than printing a string.


surjective homomorphism between principal ideal rings

I asked this question before but did not get an answer, I tried solving it myself and I think I'm heading somewhere, I just need a push in the right direction.  Let $\phi: R \to S$ be a homomorphism of commutative rings. Suppose that $\phi$ is surjective and that $R$ is a principal ideal ring (Meaning all the ideals are principal ideals, spanned only by 1 term).  Show that $S$ is also a principal ideal ring.  My "psuedo" solution  We know that $R/ker(\phi)$ is isomorphic to $Im(S) = S$ ($\phi$ is surjective).  We also know that $ker(\phi)$ is an ideal, and we know that if $R$ is a principal ideal ring and $I$ is a prime ideal then $R/I$ is also a principal ideal ring.  So I wanted to show that $ker(\phi)$ is a prime ideal, that would solve the question. But it doesn't have to be...Let's look at $ab \in ker(\phi)$:  $ab \in ker(\phi)$ implies $\phi(ab) = 0$ which implies $\phi(a)\phi(b)=0$ which implies $a \in ker(\phi)$ or $b \in ker(\phi)$ IF AND ONLY IF $S$ has no zero divisors. We we're not given that. it could be possible to find $\phi(a),\phi(b) \in S$ such that their product is zero and neither of them is zero.  And that is where I am stuck.


I am preparing a presentation with beamer from a previous paper written in latex. I want to insert in a slide the pseudocode       \begin{algorithm} \begin{algorithmic}[1] \FOR{$i=1$ to $N$} \FOR{$j=1$ to $JJJJ} \STATE $energy[i*JJJ+j] =$ \\ $ interpolate(AAA[i*JJJ+j], ZZZ)$ \ENDFOR \ENDFOR \end{algorithmic} \caption{pseudocode for the calculation of } \label{alg:seq} \end{algorithm}   but I get problems since the beamer document does not compile. I tried to use the same packages that in the latex document. I also tried to find examples through google but nothing. Could you tell me what is wron here or how could I add pseudocode in beamer )examples on the net, etc)?


Why did I just get the Announcer Badge and the Booster badge?

Today I got both the Announcer badge and the Booster badge for  that I asked last year.   I don't remember ever sharing a link to it, and it seems odd to me that I would get both badges in one day, implying that there were at least 276 people who viewed it today from a link I don't remember ever sharing.  What's going on?


How to unload kernel module permanently Ubuntu Server 20.04?

I have an Atomic PI and Ubuntu Server 20.04 installed on it. During shutdown it hangs with an error of "watchdog soft lockup" caused by DMA controller drivers called dw_dmac and dw_dmac_core  Reason is that "the HSUARTs on the SOC are not normally used on the AtomicPi, however they do appear on the 26pin connector". Solution described at the link below for 19.04 and 19.10    To be able to solve this issue the kernel modules dw_dmac and dw_dmac_core have to be unloaded.  To make this I've done the following steps without success:  1.) Checked whether these modules are running and check dependencies  lsmod | grep dw_dmac   Result:  dw_dmac                16384  2 dw_dmac_core           28672  1 dw_dmac   2.) Tried to unload with modprobe  sudo modprobe -r dw_dmac dw_dmac_core   Result:  modprobe: FATAL: Module dw_dmac is in use.   3.) Tried to unload with rmmod  sudo rmmod -v -f dw_dmac dw_dmac_core   Result:  rmmod: ERROR: ../libkmod/libkmod-module.c:799 kmod_module_remove_module() could not remove 'dw_dmac': Resource temporarily unavailable rmmod: ERROR: could not remove module dw_dmac: Resource temporarily unavailable rmmod: ERROR: ../libkmod/libkmod-module.c:799 kmod_module_remove_module() could not remove 'dw_dmac_core': Resource temporarily unavailable rmmod: ERROR: could not remove module dw_dmac_core: Resource temporarily unavailable   4.) Added the followings to /etc/modprobe.d/blacklist.conf  blacklist dw_dmac blacklist dw_dmac_core   And then updated initramfs:  sudo update-initramfs -u   Result: modules still loaded at startup  5.) Tried to modify GRUB settings at etc/default/grub to blacklist modules by adding  modprobe.blacklist=dw_dmac modprobe.blacklist=dw_dmac_core   Then sudo update-grub  Sourcing file `/etc/default/grub' /usr/sbin/grub-mkconfig: 36: /etc/default/grub: modprobe.blacklist=dw_dmac: not found   6.) Another GRUB settings modification by adding to /etc/default/grub  dw_dmac.blacklist=yes dw_dmac_core.blacklist=yes   Then sudo update-grub  Result:  Sourcing file `/etc/default/grub' /usr/sbin/grub-mkconfig: 39: /etc/default/grub: dw_dmac.blacklist=yes: not found   Could anyone help me how to unload these modules permanently?  Thanks.


If $\alpha$ is a limit ordinal, then $\operatorname{cf}(\alpha)$ is a limit ordinal

In the textbook Introduction to Set Theory by Hrbacek and Jech, , the authors first introduce the definition of increasing sequence of ordinals:        Then they introduce cofinality:        My question: how do we prove that $\operatorname{cf}(\alpha)$ is a limit ordinal?  If I take a sequence $\langle \alpha_\nu \mid \nu<1 \rangle$ where $\alpha_0=\omega$. It is clear that the limit of this sequence is $\omega$ and thus $\operatorname{cf}(\omega)=1$, which is a successor ordinal.  I don't know what's wrong with my reasoning.


Are XOFs and KDFs more usable than DRBGs?

CSPRNGs have 2 design requirements:   output unpredictability,  back-tracing resistance.    In addition to which,  added other features such as a) instance customization/personalization, b) operation administration (reseeding counter, etc.).   Of the three functions listed on , key and salt generation can be accomplished with any KDF (even ones based on plain hash functions), and nonce can be accomplished with a simple counter.   And with the introduction of dedicated-purpose XOFs in the SHA3 standard, the problem of producing arbitrary-length string from a finite-length one becomes solved along the way.   Both XOFs and KDFs are much easier to implement and use practically, so what's the point of designing DRBGs in the "NIST-SP-800-90A" way?


Factorisation thm for 2 variables plynomial

The factorisation thm for polynomial in one variable $p \in F[x]$ says that if $p(\alpha)=0$, then there is $r \in \mathbb{N} $  s.t $p(x)=(x-\alpha)^rh(x)$ where $h(\alpha)\neq0$. Is there is similiar thm for polynomial in 2(or n) variables? i.e for polynomials in $F[x,y]$?


Lyx showing incorrect math symbols in document

Ok so this is what the output looks like in the PDF document:    But this is what the input looks like in Lyx:    As you can see, the symbols that show up while writing in the Lyx document are completely messed up, the \nabla symbol shows up like a bold N, the minus sign shows up as "lyxminus" in red letters... Like what is going on here? Am I missing a package or something?  I'm using Linux Mint 19 and Lyx 2.3.0.


Human on an interstellar hibernation ship wakes up to deal with dangers caused by star-dwelling entities

A few colonization ships have left the Earth on different paths, with the inhabitants in hibernation. The main character of the story (I do forget what his 'title' or role is, however) is awakened throughout the journey for various issues. Other things that happen: the sun is made to go nova by these entities that live in stars and play a (deadly) game of making the other entity's stars nova before they can escape. They live for a very long time, so their sense of time is on an exponential magnitude to that of a redwood. I think the other ship(s) got destroyed. And for some reason I feel the main character essentially ends up being the oldest human ever. Another part of the story I can recall is the ship gets stuck moving faster than it should due to one of these entities, and the main character has to make it stop, but they don't know why, so they're really going about it the wrong way, but, end up pissing off the star 'entity'. I wish I remembered more, but that's the reason I want to re-read the book!


I have a plot like this and want to change the position of the 'tick multiplier', i.e. change where the $10^{-3}$ or $10^{-4}$ actually occurs. I don't want to change where ticks occur or remove the scaling.  \documentclass{standalone} \usepackage{amsmath,tikz,pgfplots} \begin{document} \begin{tikzpicture} \begin{axis}[scaled ticks=true] \addplot coordinates { (20000,0.0005) (40000,0.0010) (60000,0.0020) }; \end{axis} \end{tikzpicture}% \end{document}


Difference between RIGHT & LEFT JOIN vs RIGHT & LEFT OUTER JOIN in SQL

What is the difference in results between:   RIGHT JOIN and RIGHT OUTER JOIN  LEFT JOIN and LEFT OUTER JOIN ?   Can you please explain it through some examples?


Why is my SSD performing so far over spec?

While setting up a new laptop, I plugged in an SSD from an old computer, a 1TB Samsung 840 EVO 2.5" SATA III. This drive is rated for 540 MB read / 520 write according to Samsung.  At first it only benchmarked at 316/501, but after fiddling with my power settings and installing Samsung Magician and doing some optimization, speeds jumped up to 1509/1764, faster than I thought SATA drives were known to go.  After transferring some data and wiping the drive, now it's benchmarking at 7079/8159! This is over twice as fast as my NVMe SSD (Western Digital SN720 1TB), which is running at 3223/2772. What is going on here? My NVMe slots are PCIe3 so I suspect I can't get it much faster than it already is, but why is my SATA drive blowing it away?  Numbers given are from CrystalDiskMark Sequential Q8T1.


Running VPN Software as non administrative user in Windows 10?

I have several laptops in the field all using windows 10 for an OS. All users are normal user accounts no admin rights. The issue I have is that these users now need a VPN. I have installed OpenVPN on the machines, but unless I run the program as administrator it doesn't set up the tunnels correctly. It looks like it's connected but it hasn't, and the user is unable to access the end program via the VPN. I really don't want to have to make these users admins or give them any admin credentials for the machines other accounts.  The issue here isn't the VPN software.  It's the associated tunnels that fail to set themselves up. Using the answer provided in this question:    will get OpenVPN up and running, but it will fail to open the routes as shown below  Wed Oct 12 15:58:10 2016 ROUTE: route addition failed using CreateIpForwardEntry: Access is denied.   [status=5 if_index=4]  Wed Oct 12 15:58:10 2016 Route addition via IPAPI failed [adaptive]  Wed Oct 12 15:58:10 2016 Route addition fallback to route.exe  Wed Oct 12 15:58:10 2016 env_block: add PATH=C:\Windows\System32;C:\WINDOWS;C:\WINDOWS\System32\Wbem Wed Oct 12 15:58:10 2016 ERROR: Windows route add command failed [adaptive]: returned error code 1  Wed Oct 12 15:58:10 2016 C:\windows\system32\route.exe ADD 0.0.0.0 MASK 128.0.0.0 10.0.2.209  Wed Oct 12 15:58:10 2016 ROUTE: route addition failed using CreateIpForwardEntry: Access is denied.   [status=5 if_index=9]  Wed Oct 12 15:58:10 2016 Route addition via IPAPI failed [adaptive]  Wed Oct 12 15:58:10 2016 Route addition fallback to route.exe  Wed Oct 12 15:58:10 2016 env_block: add PATH=C:\Windows\System32;C:\WINDOWS;C:\WINDOWS\System32\Wbem  Wed Oct 12 15:58:10 2016 ERROR: Windows route add command failed [adaptive]: returned error code 1  Wed Oct 12 15:58:10 2016 C:\windows\system32\route.exe ADD 128.0.0.0 MASK 128.0.0.0 10.0.2.209  Wed Oct 12 15:58:10 2016 ROUTE: route addition failed using CreateIpForwardEntry: Access is denied.   [status=5 if_index=9]  Wed Oct 12 15:58:10 2016 Route addition via IPAPI failed [adaptive]  Wed Oct 12 15:58:10 2016 Route addition fallback to route.exe  Wed Oct 12 15:58:10 2016 env_block: add PATH=C:\Windows\System32;C:\WINDOWS;C:\WINDOWS\System32\Wbem Wed Oct 12 15:58:10 2016 ERROR: Windows route add command failed [adaptive]: returned error code 1  Wed Oct 12 15:58:10 2016 MANAGEMENT: >STATE:1476284290,ADD_ROUTES,,,  Wed Oct 12 15:58:10 2016 C:\windows\system32\route.exe ADD 10.0.0.1 MASK 255.255.255.255 10.0.2.209  Wed Oct 12 15:58:10 2016 ROUTE: route addition failed using CreateIpForwardEntry: Access is denied.   [status=5 if_index=9]  Wed Oct 12 15:58:10 2016 Route addition via IPAPI failed [adaptive]  Wed Oct 12 15:58:10 2016 Route addition fallback to route.exe  Wed Oct 12 15:58:10 2016 env_block: add PATH=C:\Windows\System32;C:\WINDOWS;C:\WINDOWS\System32\Wbem  Wed Oct 12 15:58:10 2016 ERROR: Windows route add command failed [adaptive]: returned error code 1   Again, if I run the program as administrator and enter admin credentials these errors don't occur; the routes are created with no errors.


The electrons always takes the easiest way in a circuit, right?  So in a parallel circuit, why does the electrons flow through all parts of the circuit and not just the one with the least resistance?


Find isomorphic extensions of $\mathbb Z_3$ by $\mathbb Z_3 \times \mathbb Z_3$ which are not equivalent

I am asking for help on the following exercise:     Find two isomorphic extensions of $\mathbb Z_3$ by $\mathbb Z_3 \times \mathbb Z_3$ which are not equivalent.   as taken from , see my other  for the notation.  There are  of order $27$. I found example extensions with the same groups that are not equivalent, but I was unable to give an isomorphism of extensions. Namely $E = \mathbb Z_3 \oplus \mathbb Z_9$ with $\mu(1) = (0,3)$ and $\overline \mu(1) = (1,3)$. Then an automorphism $\beta : E \to E$ giving equivalent extensions has to fulfill $\beta(0,3) = (1,3)$, but as $\beta(0,3) = \beta(0,1) + \beta(0,1) + \beta(0,1) = (0, x) \ne (1,3)$ this is not possible. The same argument works for the semidirect product $\mathbb Z_9 \rtimes \mathbb Z_3$, but both could not be made isomorphic extensions if we use the only non-trivial automorphism $\alpha(1) = 2$ on $\mathbb Z_3$. In $\mathbb Z_{27}$ we have only one way to embed $\mathbb Z_3$, so this will not work either. And $G = \mathbb Z_3 \oplus \mathbb Z_3 \oplus \mathbb Z_3$ will not work either, as we can alway write $\mu(Z_3) \oplus U = G$ as this is an $\mathbb Z_3$-vector space, hence make every isomorphism  $\overline \mu(\mathbb Z_3) = \beta(\mu(\mathbb Z_3)$ into an automorphism of $G$. So the only promising candidate seems to be $UT(3,3)$, but here as every element has order three I am somewhat unable to go along the same lines above to show that certain maps could not be extended to isomorphisms.  So I am asking for help on this exercise! Any hints?  EDIT: It is not a duplicate question, the other had a very specific question concerning understanding what is asked for. This one asks for help on the exercise themselve. Should not be difficult to tell that they are both different!


How to see when a package was installed?

I installed a package, i forgot when, using synaptic package manager, i want to know the installation date. I don't know how and Google doesn't seem to be helpful helping today.


This is really similar to  but some of the methods did not work for me. For example Clonezilla and GParted is not booting from my USB device (created with ).  I was following  but the the de-fragment process could not move the data to the disk so the shrink process ended shrinking 300GB (my ssd is 256GB and the data on the HDD is less than that).   Is there a BIOS option for booing Clonezilla or any other easy and clever way to clone my HDD? In worse case scenario I am planning to clean install to SSD without touching HDD. Is there any way to clone my restore partition to USB drive as a bootable device?


converting datetime to string with T07:00:00.0000000Z

I am attempting to query table storage by generating the following query:  var date = new DateTime(1954, 9, 7); var timequery = TableQuery.GenerateFilterConditionForDate("Timestamp", QueryComparisons.LessThanOrEqual, date.ToString());   I am getting a bad request when simply doing date.ToString()  The string that I need would be in the following format: 1954-09-07T07:00:00.0000000Z  How do I convert a regular DateTime to be a string in the specified format?


How do I prompt for Yes/No in a Linux shell script?

#!/bin/bash docker rm -f $(docker ps -qa) docker rmi -f $(docker images -q) docker volume rm $(docker volume ls -q)  sudo docker run -d --restart=unless-stopped -p 9090:80 -p 9091:443 --privileged -v /opt/rancher:/var/lib/rancher --name=rancher_docker_server rancher/rancher:latest   I want in this part, before sudo docker a question arises whether to continue?


How to prevent Mac from changing the order of Desktops/Spaces

You may have encountered a situation in which Mac changes the order of desktops based on some events like alerts on a program or a web page in browser. How could I disable this logical change? Note: I'm using El Capitan, but I had this problem since Mavericks.


Excel VBA - How to get data from XML URL?

I need to get the data from FIELD NAME="sitr2" & FIELD NAME="sitr4". Below is the XML code:  <SEGMENTS> <SEGMENT NAME="webcluster"> <RESULTPAGE> <QUERYTRANSFORMS>...</QUERYTRANSFORMS> <NAVIGATION ENTRIES="0"> </NAVIGATION> <CLUSTERS/> <RESULTSET FIRSTHIT="1" LASTHIT="1" HITS="1" TOTALHITS="1" MAXRANK="10000" TIME="0.5673"> <HIT NO="1" RANK="10000" SITEID="0" MOREHITS="0" FCOCOUNT="0"> <FIELD NAME="rank">10000</FIELD> <FIELD NAME="personnames"/> <FIELD NAME="concepts">environment;flexible;storage;virtual;growing</FIELD> <FIELD NAME="companyteaser"/> <FIELD NAME="locationteaser"/> <FIELD NAME="personnameteaser"/> <FIELD NAME="nav">...</FIELD> <FIELD NAME="taxonomy">t/na</FIELD> <FIELD NAME="documentid"/> <FIELD NAME="uniqueid"/> <FIELD NAME="sitr1">4038b5c5-c90b-4ae3-a165-a5e0db9c10d4</FIELD> <FIELD NAME="sitr2">097cf4a8-2755-4c62-939c-9402e0a4e3e2</FIELD> <FIELD NAME="sitr3">Unknown</FIELD> <FIELD NAME="sitr4">0.3</FIELD> <FIELD NAME="sitr5"/> <FIELD NAME="sitr8"><matches> </matches></FIELD> <FIELD NAME="int1">21854</FIELD>   I got no idea where to start. I need to extract and insert into excel. Hope someone could help me.


Noob Alert  I was trying to copy the displayed <this.state.response> which is inside an
. The
 tag should act as the copy button for which I would like to give the copy action. I tried using react-copy-to-clipboard package but failed as I already have some states defined in my code.
     //content to be copied
 {this.state.response}
      //acts as the copy button
Copy to clipboard

   Home.js    import React, { Component } from "react"; import { Container, Row, Col, ButtonGroup, Button } from "reactstrap"; import {CopyToClipboard} from 'react-copy-to-clipboard'; import Header from "./Header.js"; import Footer from "./Footer.js";  import "./Home.css";   export default class Home extends Component {   state = {      response: ''   };     componentDidMount() {     this.callApi()       .then(res => this.setState({ response: res.chunk }))       .catch(err => console.log(err));   }      callApi = async () => {     const response = await fetch('/password-api');     const body = await response.json();      if (response.status !== 200) throw Error(body.message);      return body;   };    handleClick = async () => {     await this.callApi()        .then(res => this.setState({ response: res.chunk }))  };       render() {     return (
                   <Container>           <Row>             <Col sm="12" md={{ size: 8, offset: 2 }}>

 {this.state.response}

Copy to clipboard

                                                    {/* <ButtonGroup>             <Button>Secure</Button>             <Button>Complex</Button>               </ButtonGroup> */}             </Col>           </Row>           <Row>             <Col sm="12" md={{ size: 8, offset: 2 }}>               <button onClick={this.handleClick} id="get-pass-button" className="button">                 Generate Password               </button>             </Col>           </Row>         </Container>
     );   } }     I believe this question is related to npm react-copy-to-clipboard!


Differential equation $x'=x^2- \frac{2}{t^2}$

$x'=x^2- \frac{2}{t^2}$  Hmm I have not idea how to do it... Maybe any smart substitution could work?


I am new to qqplot and trying to figure out the labels on the x-axis of this plot:  The left plot is the Verbal SAT score of 105 college students majoring in CS. The right plot is the GPA score.  I understand that the qqplot means "quantile vs quantile", the y-axis is each student's test score, but what is the x-axis and why it is from -2 to 2?  Update: For anybody whose looking for a more visual explanation of QQ-plot, check out this video on youtube:  After reading and watching dozens of articles and videos, let me explain what is the x-axis and the y-axis in layman's term. The y-axis is the values you recorded. Like the verbal SAT score in my example. Because there are 105 of verbal SAT sores, there should be 105 values on the x-axis as well. There are three steps involved in order to get these 105 values: Step 1 Sort the 105 values in ascending order and give each one of them an index number starting from 1, 2, 3 .... all the way up to 105. Let's use i to denote each index number. Step 2 Use this formula to find a list of percentages (I will explain what are they later, just keep on reading): $\left(\dfrac{i-0.5}{n}\right)$ So you will get 105 values that looks like this: $\left(\dfrac{1-0.5}{105}\right)$, $\left(\dfrac{2-0.5}{105}\right)$, $\left(\dfrac{3-0.5}{105}\right)$ ... $\left(\dfrac{105-0.5}{105}\right)$ Step 3 Find the z-score of the values we just calculated in step 2. These z-scores are the x-axis of the qq-plot Now, plot the verbal SAT scores as the y-axis and the z-scores as the x-axis, you will get a qq-plot.  Ok, now it is the time to explain the meaning of step 2 & 3. Let's start with the definition of cumulative distribution function. Let's say we have a test and the maximum score a participant can get is 100 points. After taking the test, 50% of the participants scored 60 points or less, 40% of the participants scored 50 points or less, 30% of the participants scored 40 points or less, and so on. The cumulative distribution function (aka. CDF) takes one input, a test score, and it outputs a percentage which tells you the percentage of people who scored less than or equal to that test score. With the example case above, If I put 60 points into the CDF function, I should get 50% back. If I put 50 points I get 40%. The inverse of the cumulative distribution function takes one input, a percentage and it outputs the corresponding test score. If I put in 50%, it should give me 60 points. It does nothing fancy other than reverse the function of CDF. Step 2 basically calculated a list of percentages and when we feed that list of percentages into Step 3  and get back a list of z-scores. So Step 2 + Step 3 = calculating the inverse of the cumulative distribution function. The list of percentages calculated in Step 2 looks like this: 0.005, 0.014, ... 0.995. The list of z-scores in Step 3 looks like this: -2.575829304, -2.197286377, ... 2.575829304. It means for participants who scored less than or equal to 0.5% (0.005 x 100) of the total participants, the corresponding z-score is -2.57. So what does the qq-plot tell us in our example: If the verbal SAT score indeed follows a standard normal distribution （mean=0, variance=1）, then the outline of the histogram of the test scores should resemble the bell curve of the standard normal distribution. But it is really hard to judge if a histogram matches the shape of a bell curve, a straight line is probably a better choice for the naked eyes. Let's match the observed values against the z-scores.


Extending stay by a day in Schengen region

I have a Schengen visa (single entry) which is valid from 22nd September to 30th October. When I had applied, I had written that I plan to leave the Schengen region on 14th (Friday). However, I am planning to extend the stay by a day and leave on 15th. Will this cause a problem?


Better explicit notation for $\sqrt {(-2) ^2} = \sqrt {2^2}$ seemingly implying $-2=2$ type questions

EDIT : This about explicit notation and clarity, usage of $\sqrt{(-x)^2}= x$ is for demonstrative purposes not for the problem itself.  $\sqrt {(-2) ^2} = \sqrt {2^2}$ causing confusion $-2=2$ which is nonsense.  What seems to be needed is somehow distinguishing between $-2=2$ and explicitly stating $2,-2$ are in the set $S=$same equivalence class of numbers $k$  s.t. $k^2$ having the same value.   Another observation is the order of operation is important, $\sqrt {(-2)^2} = \sqrt {2^2}$ can be evaluated as either $\sqrt {4} = \sqrt {4} =2$ or $ {-2} =  {2}$ , how ever implicitly it known that the square function performs first and only after that the square root function can operate, how could this implicit knowledge be worked into explicit notation?  Are there any notations that can be used to make order of operation explicitly visible or instead of ending up with $2=-2$, somehow end up with $2 \equiv-2$ with respect to their squares having same values?


Strange graphics issues such as flickering application windows and inconsistent display lagging

My computer was acting really strange; the windows were flickering and parts of windows of different applications were partly appearing at random places. Also when I was typing, my computer seemed to automatically selected text and copied it, but it could also be that it just duplicated a part of the screen of a few seconds ago. Hard to describe, but unworkable. My Thinkpad carbon passed all hardware tests and I installed a fresh Ubuntu install. Still the same behavior. I found a solution that I wanted to share.


I'm using this code:  import java.util.Scanner; import java.util.Arrays; import java.util.Random;   public class Matrix {     public static void main(String[] args)     {         Scanner enter = new Scanner(System.in);         int[][] firstMatrix = new int[4][4];         int[][] secondMatrix = new int[4][4];         Random spin = new Random();            System.out.println("Please enter 16 numbers to populate the array: ");          for (int count = 0; count<firstMatrix.length;count++) // nested for for user input to populate 4x4 array         {               for (int count2 = 0; count2 < firstMatrix[count].length; count2++)             {                  firstMatrix[count][count2] = enter.nextInt(); // populate array with user input                }          } // end array population              System.out.printf("The sum is: %d%n", sumMatrix(firstMatrix)); // call sumMatrix             System.out.println(firstMatrix[0][0]); // debug                for (int count3 = 0; count3<secondMatrix.length; count3++) // nested for to populate array with random numbers 1-100, row             {                 for (int count4 = 0; count4<secondMatrix[count3].length; count4++) // column                  {                     secondMatrix[count3][count4] = 1 + spin.nextInt(100); // 100 inclusive, generate and populate array                 }             }               System.out.println(secondMatrix[0][0]); // debug to show that it is properly printing the correct element               for (int i = 0; i<secondMatrix.length; i++)              {                 for (int j = 0; j<secondMatrix[i].length; j++)                     System.out.print(" " + secondMatrix[i][j]); // print the total array ( this process can be used to print the returned array )                }          System.out.println(); // debug               int arrayTotal = firstMatrix[0][0] + secondMatrix[0][0]; // debug                 System.out.println("The element total is " + arrayTotal); // debug                     System.out.println();          addMatrix(firstMatrix,secondMatrix); // call addMatrix               System.out.println("Programmed by Stephen Mills");     }  // end main                public static int sumMatrix(int[][] array) // method to sum the elements of the array         {                 int total = 0;                  for (int number = 0; number<array.length; number++) // row                  {                     for (int number2 = 0; number2<array[number].length; number2++) // column                         total += array[number][number2]; // sum of all elements                 }                     return total; // returns the sum          } // end sumMatrix          public static int[][] addMatrix(int[][] array1, int[][] array2) // improper method         {             int[][] thirdMatrix = new int[4][4];              for (int count4 = 0; count4<thirdMatrix.length; count4++)             {                 for (int count5 = 0; count5<thirdMatrix[count4].length; count5++)                     thirdMatrix[count4][count5] = array1[count4][count5]+array2[count4][count5];               }             System.out.println(Arrays.toString(thirdMatrix));             return thirdMatrix;         } // end addMatrix7    }   Most of the program works as intended but I'm getting this "[[I@3d4eac69, [I@42a57993, [I@75b84c92, [I@6bc7c054" output when trying to print my array. I've tried several methods, including simple println, toString, setting a variable equal to the method call, and I've tried putting the print statement in main first and then in the method second. Any ideas why this is happening?


I am an international student in the United States with an Indian passport. I just had my first name on my passport due to which the visa I got had FNU(First name unknown) and my first name as my last name on my visa.  Recently I applied for a new passport to add my last name on it, so I got it. Now my new passport has my real first and last name on it but my visa is still the same. What should I do? Di I need to change my Visa name or any suggestion you guys have for me? I am a little scared because soon I am going to apply for OPT and don't want that to be an issue. Any kind of help will be appreciated .


I have a server and the Ender dragon has been defeated.  However, returning to The End does not respawn the Ender Dragon.  How can I get the final boss back on a vanilla server without using mods?


Object dimensions changing but not changing

I am having a simple problem with Blender 2.76b using Python 3.4.2.  I'm trying to change the dimensions (not scale) of a mesh, and then put another object next to it, depending on the new size.   However, after changing the dimensions (which works fine, the actual size in the animation changes) it still gives me the original dimensions when called.    Code:  add_cube  = bpy.ops.mesh.primitive_cube_add   add_cube(location=(0,0,0)) actor_name = bpy.context.scene.objects.active.name  #randomized size to check if post resize call is working: sizex = random.randint(3,10) sizey = random.randint(3,10) sizez = random.randint(3,10) bpy.data.objects[actor_name].dimensions = (sizex, sizey, sizez) #end of random resize test  objdim = bpy.data.objects[actor_name].dimensions  print('Actor Dimensions: ', objdim)   A standard cube is (2,2,2) big.  When the code runs it changes the object size, but then prints "Vector((2.0, 2.0, 2.0))" when it should be bigger.  Putting in static values instead of random numbers produces the same problem.  Running this in the python command line in the scripts window works fine, running from script does not.  Am I missing some refresh thing?  Anyone come across this?  It's like it's not refreshing the actual dimensions when I call them.


I have a doc which I load with interop. I need to find match content with a regex. Some words in the doc are between $$ : $$theWord$$ So I need to get all of them for displaying to user and know what he wants to set for replace.  object fileName = System.IO.Path.Combine(templatePath, pj.Nom); object missing = Type.Missing; Application word = new Application(); Document doc = word.Documents.Open(ref fileName, ref missing, ref missing, ref missing, ref missing, ref missing,                                                 ref missing, ref missing, ref missing, ref missing, ref missing, ref missing,                                                 ref missing, ref missing, ref missing, ref missing); doc.Activate(); string content = ((dynamic)doc).Content.Text; Regex regex = new Regex(@"\$\$.*\$\$$", RegexOptions.Multiline);  List<string> tags = regex.Matches(content).Cast<string>().ToList();   The problem is my regex get only one word who begin on the first && found and finish on the last...  Please help me, I hate regex :(


How can I get dramatic shallow DOF with a kit lens?

I'm currently using an entry-level DSLR with 18-55mm lens and having great trouble trying to creating a blurred background effect in my photos. Now matter what aperture or shutter speed I choose, I'm not able to get it.  There's a general question about , but what specific things can I do to get this effect with an entry-level lens?


Automatically run a command on start up?

I was kindly helped on this forum a few months ago to fix my Wifi. Only problem is I have to run the command in the terminal at the start of every session.Each time I need to run-  sudo modprobe -v brcmsmac   How can I make this process run automatically?  Many thanks!


Why old PMOS/NMOS logic needed multiple voltages?

Why does old PMOS/NMOS logic needed multiple voltages like  +5, -5, and +12 volts? For example, old Intel 8080 processors, old DRAMs, e.t.c...  I'm interested in the causes on the physical/layout level.  What was the purpose of these additional voltages?  Yes, this question is about stuff which was used 35 years ago.


Java Question about Setting a Word as a Variable

I am making a rock paper scissors program. I want the user of the program to enter either rock, paper, or scissors (hence the imported scanner) and I want the computer to choose a random number (I will import a java.util.Random) that corresponds to another rock, paper, or scissor.  So I am trying to make the program RECOGNIZE a word as something significant. That is to say, if the user inputs "rock" in the scanner, the computer will do some output. In the below code, I tried to get the computer to output "yes" if the user inputs "rock". To do this, I set a variable called "player" to be the inputted text, and a String rock to be the phrase "rock". I then said that if player=rock(="rock"), then we will get "yes".  There were no errors in the program. But when I inputted "rock" into the scanner, the program did nothing. What did I do wrong and how can I correct it?  import java.util.Scanner;  public class Refined {      public static void main(String[] args){         Scanner abc = new Scanner(System.in);         String rock = "rock";          String player;         System.out.println("Rock, Paper, or Scissors?");         player = abc.next();         if(player == rock){             System.out.println("yes");          }     }


Change all the // character for commenting in c++ to the c comment characters /* */

I m trying to change some characters in a file, like this:  //this is a thest of how this works #include <stdio.h>  int main() { // declare some variables here int num1 = 4; float num2 = 3.5;  // print the result  printf("The result is %f\n", num1 * num2); // this does it  /* does it work? */ return 0; }   I want to change all the // character for commenting in c++ to the c comment characters /* */ making the file then look like this:  /*  This is a test of how this works */ #include <stdio.h>  /*this is a thest of how this works */ #include <stdio.h>  int main() { /* declare some variables here */ int num1 = 4; float num2 = 3.5;  /* print the result  */ printf("The result is %f\n", num1 * num2); /* this does it */  /* does it work? */ */ return 0; }   I do not know much bash at all and this is what i came up with sed 's/////* *//g' myprog.c  it did not work, what am i doing wrong or what do i need to do to make these changes? Im trying to make it a one line command


What are the Complex (Non-Real) Eigenvectors of $3\times 3$ Rotation Matrices?

A $3\times 3$ rotation matrix $R$ that rotates $\mathbb{R}^3$ around the  unit vector $v\in\mathbb{R}^3$ by angle $\theta$ (as defined by  ) satisfies the eigendecomposition  $$ R=W\Sigma W^\mathrm{*} \enspace, $$ where $$ W=\left(\begin{matrix}v \;|\; x \;|\; y \end{matrix}\right)  $$ is a unitary matrix of eigenvectors, and $$ \Sigma=\mathrm{diag}\left(1,e^{i\theta},e^{-i\theta}\right) $$ is the matrix of the corresponding eigenvalues. What expressions define the non-real eigenvectors $x$ and $y$?


There have been talks that md5(md5) is better than md5 alone, but some say it doesn't do anything, can someone help on how to make this more secured? I'm so confused with the mixed feedback.  $query="INSERT INTO `users` (`email`, `password`)     VALUES('".mysqli_real_escape_string($link, $_POST['email'])."',            '".md5(md5($_POST['email']).$_POST['password'])."'           )";


Here is example how I do that in Linux, but in Windows I don't have strptime function anyone can help me solve this problem?  #include <stdio.h> #include <time.h> #include <sys/time.h>  time_t to_seconds(const char *date) {     struct tm storage = {0, 0, 0, 0, 0, 0, 0, 0, 0};     char     *p       = NULL;     time_t    retval  = 0;      p = (char *) strptime(date, "%d-%b-%Y", &storage);     if (p == NULL)     {         retval = 0;     }     else     {         retval = mktime(&storage);     }     return retval; }  int main(int argc, char** argv)  {     time_t d1 = to_seconds("16-Jun-2015");     time_t d2 = to_seconds("13-Jun-2015");     if(d1 > d2)     {         printf("date 1 > date 2");     } }


Why we take direction of current opposite to direction of electron.  As electrons moves in a circuit. And I read in my books that it is conveniently taken  if it so how galvanometer works (gives direction of current)


The No. of Continuous function satisfying the condition $xf(y)+yf(x)=(x+y)f(x)f(y)$

Could anyone tell me?   The No. of Continuous function satisfying the condition $$xf(y)+yf(x)=(x+y)f(x)f(y)$$ is   $1,2,3,$ or  none of them?  or give me hints please.


View Comments and/or Answers While Editing

Quite often, comments on a question ask for the original poster to add details.  For example:  What architecture are you compiling for? What version of XYZ are you using?  I think it would be helpful for these comments to be visible while editing the original question.  That way, we won't have to keep going back and forth or open a new tab.


How to move the window control buttons in 18.04

I have recently updated Ubuntu to 18.04, and my window control buttons have changed from left to right (in user perspective).  Are there any ways to change it back to the way it was in 16.04 or earlier versions?


$ X \sim N(\mu,\sigma^2) $  $ Y = \frac{\exp(X)}{1+\exp(X)} $  Y has a logit-normal distribution.  When I have a correct estimate of the mean, say $\bar{Y}$, of the logit-normal distribution, how can use it to get a correct estimate of $\mu$ ?  I don't have full sample from logit-normal distribution, but only the correct estimate of the mean. I know that $ \log(\dfrac{\bar{Y}}{1-\bar{Y}}) $ is not the right answer due to Jensen's inequality.


Checking to see if a column exists in a data reader

Is there a way to see if a field exists in an IDataReader-based object w/o just checking for an IndexOutOfRangeException?  In essence, I have a method that takes an IDataReader-based object and creates a strongly-typed list of the records.  In 1 instance, one data reader has a field that others do not.  I don't really want to rewrite all of the queries that feed this method to include some form of this field if I don't have to.  The only way I have been able to figure out how to do it so far is to throw the 1 unique field into a try/catch block as shown below.  try {     tmp.OptionalField = reader["optionalfield"].ToString(); } catch (IndexOutOfRangeException ex) {     //do nothing }   Is there a cleaner way short of adding the "optional field" to the other queries or copying the loading method so 1 version uses the optional field and the other doesn't?  I'm in the 2.0 framework also.


If you grapple a creature while staying out of its reach, can it still attack you?

A  is able to grapple up to 10 creatures with its tentacles, the reach for this attack is 30 ft.     Tentacle. Melee Weapon Attack: +17 to hit, reach 30 ft., one target. Hit: 20 (3d6 + 10) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained. The kraken has ten tentacles, each of which can grapple one target.   Can a creature with a reach of 5 ft. which is grappled 30 ft. away from the Krakens position attack it with a melee weapon attack? It would make sense, that one could aim for the grappling tentacle, but is it RAW/RAI?


Windows 8.1 is Completely Blocking Ubuntu

A few days ago, I upgraded my Windows 8 Lenovo U410 ideapad to Windows 8.1, and it proved to be a terrible mistake. It seems like the only visible change that it has made is adding the start button. Meanwhile, it disabled my audio, and I had to go and reinstall drivers from Lenovo's website. Even worse, it is completely blocking me from running Ubuntu in any way possible.  I have my hard disk partitioned into three main partitions: 100GB for Windows (in NTFS); 100GB for Ubuntu (in ext4...I think); and a 550GB storage drive (in NTFS). Then on start up, the Ubuntu GRUB screen ( one) would come up and I would be able to choose between booting into Ubuntu and Windows 8. However, now after the update, I boot straight into Windows 8.1, and cannot access the Ubuntu file system.  This wouldn't be that big of a problem, if it wasn't for the fact that three almost-finished Honors English papers are on there, and I NEED them. So first I tried booting into the Ubuntu partition from the bios, which didn't work, and neither did trying to boot into it from the "Use a Device" menu in the Windows "Advanced Startup" menu. Next, I tried moving the Ubuntu partition to the first spot in the boot sequence, and starting up my computer again. When that had no effect, I created an Ubuntu USB drive, and went through all the same steps (this is what the answers to questions similar to mine recommend). Again, no result. I've also noticed that even after changing the boot sequence in the BIOS, Windows Boot Manager forces itself back to the front.  I'm at a loss for what to do, and I really need those English papers, so any help is MUCH appreciated. Thank you for reading this far, and thanks in advance for any advice.


If $T$ is a tree and $T_1, T_2, \ldots , T_k$ are all subtrees of $T$ such that the vertices of $T_i$ are $V_i$. Suppose $V_i\cap V_j$ is non-empty for all $i$ and $j$. Show that there is a vertex that exists in all $T_i$.  I'm honestly not even sure what the question is asking. This is just a completion grade, but I honestly do want to know how I should go about proving this. What method to use?


I want to change the value from 1521 to 1525 in FROM_HOST only in file gexhosts.cat:  FROM_HOST   db201521 TO_HOST     db201521   Is there a way to do that or some work around?  I would really prefer if we could use sed as I am using sed for many other activities of mine.


ubuntu software centre empty error after fresh os installation

after fresh new installation of 16.04.1 the ubuntu software centre is empty  ... does not show any software at all !   and also  controls are missing   howto recover ?


How do i print the path of excuatable in echo

SO i have a Bash Script like this and goal is to determine the path of an executable file and i want to print it, here is what i'm doing #!/bin/bash  exepath=which exe  echo "$exepath"  Now this instead of printing path its starting the exe file in my system, how do i print the path stored in exepath variable.


What are some best resources of self study for a beginner black-box tester?

I have just started working as a manual/black-box tester in a QA team. I am currently learning about testing techniques/practices from others. What are some good resources which i can use to make a good foundation in software testing?  please link reference material including websites , blogs, free courses etc.


How to have aligned equations in a caption?

The following is my MWE, inspired from the answer to  (where my query seemed to merit a separate question, so here it is!):  \documentclass{article} \usepackage{caption} \usepackage{amsmath} \usepackage{pgf,tikz} \usetikzlibrary{arrows,shapes,calc,intersections,through,backgrounds}  \begin{document} \begin{figure}[b]    \begin{tikzpicture}[line cap=round,line join=round,>=triangle 45,x=1cm,y=1cm]                   % More stuff here - not relevant I think...    \end{tikzpicture}    \caption{\label{q}\leavevmode\\\begin{minipage}{\linewidth}          \begin{align*}             a &= b \\ c &= d          \end{align*}       \end{minipage}    } \end{figure} \end{document}   With the above, I'm getting the following error:  ! Argument of \@caption has an extra }. <inserted text>                 \par l.19    }   I'm not sure how to debug this!


How to run this kind of command from within "find"?

I'm using FreeBSD and having difficulty with commands that include {} as part of a string. For example, if renaming the found files. Note that this is an example of the situation. The question itself is about working around the issues of "{}" syntax in general:  find . -type f -name 'data*' -execdir mv {} OLD_{} \; find . -type f -name 'data*' -execdir mv {} archive/{} \;   Note that -execdir avoids issues with the containing dir path by executing the command from within the containing dir and expanding {} to just the filename.  There are two problems:   How to correctly quote the args in the -execdir mv clause (many files will have spaces or single quotes in their names). How to get the target to substitute the filename at all.   The second problem arises because {} for "found item's path" only seems to be expanded if it's surrounded by leading/trailing spaces, which messes up the command args. Example with non-space leading and trailing characters:  # /usr/bin/find . -maxdepth 1 -execdir echo "(result):" {}  \; (result): . (result): dir 1 (result): dir 2 (result): dir 3  # /usr/bin/find . -maxdepth 1 -execdir echo "(result):"{}  \; (result): (result): (result): (result):  # /usr/bin/find . -maxdepth 1 -execdir echo {}":(result)" \; :(result) :(result) :(result) :(result)   man find states that " Historic implementations of the -exec and -ok primaries did not replace the string “{}” in the utility name or the utility arguments if it had preceding or following non-whitespace characters.  This version replaces it no matter where in the utility name or arguments it appears", but that doesn't seem to be happening.  How can I execute the command I want to run?


Show that $\psi_a:G\rightarrow G',a\in G,\psi_a(g)=aga^{-1}$ is homomorphism one to one and onto

Let $G$ be a group and $\psi_a:G\rightarrow G,a\in G,\psi_a(g)=aga^{-1}$, I need to show that $\psi_a$ is homomorphism one to one and onto  It's not the same question like      "Is the conjugation map always an isomorphism?"   because here I need to show why $\psi_a$ is one to one and onto  Attempt:  $\psi_a(g_1g_2)=ag_1g_2a^{-1}$  $\psi_a(g_1)\psi_a(g_2)=ag_1a^{-1}ag_2a^{-1}=ag_1g_2a^{-1}$  $ \Rightarrow \psi_a $ is hom'


I have python code with the directory structure -     main.py basics.py component1   file1.py   file2.py component2   file1.py   file2.py   I want the code in the directories component1 and component2 to use code from basics.py. What is the most pythonic way of doing this?  Thanks!


Exclude sub-directories from tree output

I would like to document a directory structure, and installed tree to do so.  I don't wish to include files but only directories and symbolic links which point to directories (haven't decided if the symlinks should be recursive, and either way is fine).  There are some directories which I would like to include the directory name, but not any directories (or files) within it.  Looks like I need -d to only display directories.  I have been able successful exclude directories using -I somedirectory, however, not to exclude sub-directories such as -I somedirectory/somesubdirectory.  For instance, the intent of the below command is to display all directories and sub-directories within ~/some/base/directory/ except for sub-directories within ~/some/base/directory/myfirstdirectory/notthisone or ~/some/base/directory/myotherdirectory/oreventhisone (note that ~/some/base/directory/myfirstdirectory/notthisone, etc should be included but just not its sub-directories).  tree -d -I "myfirstdirectory/notthisone|myotherdirectory/oreventhisone" ~/some/base/directory   I've also tried escaping / or replacing it with a . wildcard.  How are given sub-directories excluded from tree's output?


Inverse linear model doesn't seem exact inverse

I'm dealing with a quantity that diminishes over time from 100% to 0%.  I'm trying to plot the values, a lm abline, and large indicative points where the graph intersects y==100% and y==0%.  I'm finding the results of lm(y~x) don't appear to be the inverse of lm(x~y) and I'm confused why this should be for a deterministic calculation.  This illustrates in R:  set.seed(100) d = data.frame(t = sort(sample(1:60,10)), q = sort(sample(1:100,10), dec=T))  # linear model - dependant y fit = lm(q ~ t, d)  # predicting x where y == c(100,0) - i.e. dependant x pred = predict.lm(lm(t ~ q, d), data.frame(q=c(100,0)), se.fit=T)$fit pred = data.frame(t = pred, q = c(100,0))  plot.new() plot.window(xlim=c(0,60), ylim=c(0,100)) axis(1); axis(2) points(d) abline(fit) points(pred, pch=16, cex=2, col='red')   Why don't the red points not fall on the line?  I know the modelling/plotting here is probably topsy-turvy, but I'm interested in the principal..


What do the hearts around a Pokestop mean?

I was walking about and I loaded up Pokemon Go to check if there were any Pokestops in my area. There were two, but one looked different than normal. When I clicked on the Pokestop, there were floating hearts around it.   Are there anything special significance to these hearts?


A recent trend toward wider tires (cf ) also led to wider rims and a closer match of rim and tire widths.  In the past it was considered that tires need to be considerably wider than their rims. For example,  requires at least 40 mm nominal width in a 23 mm rim (measure between inner flanges). ISO 4210 (cf ) requires at least a 37 mm tire on the same rim.  As a recent example, my new bike (2017 Merida CX 600) came with a 700x23C rim and 32-622 tires. This choice of the manufacturer suggests it is a safe combination. The rim lacks hooks though (see below), which might make it comparable to a narrower specification.  New developments, such as tubeless, hook-less rims, and tubeless tire beads made this question more complicated then it was a decade ago. This merritts to discuss this beyond Brown and ISO 4210.   What is the smallest width a tubeless tire may have to be mounted on a rim of given width?


I am following section 3.4 of Evan's book "Partial Differential Equations". In this section he considers the Burgers equation, $$u_t + \bigl(\frac{u^2}{2}\bigr)_x = 0$$ with initial data $$g(x) = \begin{cases} 0, & x < 0\\ 1, &0 \leq x \leq 1\\0, & x > 1\end{cases}$$ I have been able to follow how he obtains the solution for $0 \leq t \leq 2$, $$u(x,t) = \begin{cases} 0, & x < 0\\  \frac{x}{t},  & 0 <x < t\\ 1,  & t < x < 1+\frac{t}{2}\\0, & x > 1 + \frac{t}{2}\end{cases}$$ However he notes for $t \geq 2$ this solution breaks down as the rarefraction wave and the curves stemming from the initial condition $g(x) = 0$ intersect. He uses the Rankine-Hugoniot jump condition to find that $$\dot{s}(t) = \sigma = \frac{x}{2t}$$ This is where he begins to lose me. He claims that this implies $$\dot{s}(t) = \frac{s(t)}{2}$$ with $s(2) = 2$. He claims by solving this ODE we find $$s(t) = \sqrt{2t}$$ and so the final solution for $t \geq 2$ is $$u(x,t) = \begin{cases} 0, & x < 0\\ \frac{x}{t}, & 0 < x < \sqrt{2t}\\0, & x > \sqrt{2t}\end{cases}$$ How does he obtain that ODE? Moreover, how does he conclude that the shock occurs at $t = 2$ (aside from graphically)?


I added the user myuserto Postgres.  Then I added the database mydatabase in the pgAdmin III GUI and restored from a backup file. So the owner of mydatabase is the superuser postgres.  Then I tried to give all rights to access and modify mydatabase to myuser. I logged into psql as user postgres:  psql -d template1 -U postgres     and then I ran this query:  GRANT ALL PRIVILEGES ON DATABASE mydatabase TO myuser   Now I can use myuser to log, but if I try a simple query I get this error:   ERROR:  permission denied for relation table_name    Am I missing something? Can you help me solve that?


Is the Cantor set made of interval endpoints?

The Cantor set is closed, so its complement is open.  So the complement can be written as a countable union of disjoint open intervals.  Why can we not just enumerate all endpoints of the countably many intervals, and conclude the Cantor set is countable?


The Cardinality of $(a,b)$ and $\Bbb{R}$

I need to prove that the interval $(a,b)$ and the set of Real numbers share the same cardinality.    I understand that I need to find a bijection between the two sets. I have been hinted to use something like $(0,1)$ or $(-1,1)$ to find a bijection then extend it to all reals. I need advice on how to set up the actual proof. Trigonometric functions are not to be used in this proof.


Is It possible to write in the same line and don't write in several row?

I would print the cpu usage with this simple python script. I would write the result, erase that row and re-write on the same line as like as windows shell does with some commands. Is it possible?  import psutil                                     #import tsutil import time  def printit():     while(1):         print(psutil.cpu_percent())         time.sleep(3) printit()   This print line per line. I would the result always change on the same line


Extract `m`th (first) column value for line with specific `n`th (second) column value from file

I need to Write an awk command that will return the identification number from the following table for only the lines where the title is Turtle. This table is stored in turtle.txt  Id Num. Title           CatchDate 433417  RedTurtle       2001-06-29 493303  BlueTurtle      1998-09-20 259497  Turtle          1985-05-08 229505  RedTurtle       1994-07-13 473076  OrangeTurtle    2002-03-08 221907  Blueturtle      1999-07-02 457032  Turtle          1993-04-09 490359  RedTurtle       1996-11-12 494595  SnappingTurtle  1985-05-20 402421  BlueTurtle      1999-08-16


How do I summon a custom villager with multiple custom trades?

I am trying to figure out how to summon a custom villager with multiple custom trades. Can you help me make a command? I am trying to trade 4 emeralds for a pair of diamond boots with protection 1, 8 emeralds for a pair of diamond boots with protection, too.


How can I compare if two objects are equal in jQuery.   var a = { id:"1", name:"name"}; var b = { id:"1"}; b.name = "name";   How can I check for equality between a and b ? Is there a method similiar to .equals() in JAVA which can be overridden ?


Installation PROBLEM : unity Ubuntu-Desktop

Currently I am using Gnome-Shell but now I want to use unity Desktop. I tried to install ubuntu-desktop by following command  sudo apt-get install ubuntu-desktop   Its showing following error  The following packages have unmet dependencies:  ubuntu-desktop : Depends: ubuntu-session but it is not going to be installed                   Depends: unity-control-center but it is not going to be installed                   Depends: unity-settings-daemon but it is not going to be installed                   Recommends: xul-ext-webaccounts but it is not going to be installed E: Unable to correct problems, you have held broken packages.


Why are functions as a type of relations special?

I.E. Why are relations where each member of the domain having one and only one mapping to a member in the range so important?  I was wondering since most of mathematics that I'm familiar with (high school math) focus much on functions.  Also do upper level mathematics study relations that are not functions just as much?


Implement `[1,2].contains(2)` in JavaScript

Essentially I require:  if( [1,2].contains(2) ) {...}   I am surprised that I can't find a simple solution to this.  Is it possible to add a contains method to JavaScript's List type?   offers:  _.contains([1,2], 2);   However, _ is JQuery, and it is still rather clumsy.


Proving that: $\forall n \in \mathbb{N} :|f^{(n)}(x)|\leq \frac{1}{n+1}$

Suppose $x>0$ and we have function $f(x)=\frac{\sin x}{x}$ how can we show $$\forall n \in \mathbb{N} :|f^{(n)}(x)|\leq \frac{1}{n+1}$$ I need a hint to show this property .Thanks in advance . I tried for $n=1 ,2$  by finding maximum of $|f'| ,|f''|$ but I get stuck to show for $n$


Trigonometry - represent as product: $1 + 2\cos\alpha$

Represent the following as a product: $1 + 2\cos\alpha$ Please help if someone can solve this?


I can't create a list of abbreviations. I have been using nomencl package.  I put \makenomenclature and   \nomenclature{symbol}{name of symbol} \printnomenclature   But nomenclature doesn't appear.  Thanks


Arrange the following growth rates in increasing order: $O (n (\log n)^2), O (35^n), O(35n^2 + 11), O(1), O(n \log n)$

I want to Arrange the following growth rates in increasing order  This order are following : $O (n (\log n)^2), O ((35)^n), O(35n^2 + 11), O(1), O(n \log n)$  Please give me idea how to arrange growth rates in increasing order  Regards, Jatin


Order and degree of a differential equation

Here is a question in my book  Find the order and degree of the differential equation $$y=1+\frac{dy}{dx}+\frac{1}{2!}{\left(\frac{dy}{dx}\right)}^2+\frac{1}{3!}{\left(\frac{dy}{dx}\right)}^3+\cdots$$  At first sight we can conclude that the order is $1$ and the degree is undefined as  as the power of $\frac{dy}{dx}$ continues to increase and has no limit.However  my book gives the following solution  Rewrite the DE as $$y=\exp\left({\frac{dy}{dx}}\right)$$ $$\implies \frac{dy}{dx}=\ln y$$ whose order and degree is 1 .  Now ,I completely agree with this solution however I find it rather counterintuitive to my first line of thought .If the book is correct how can it be justified to prove my intuition was wrong?


What is the result of  $\lim_{(x,y)\to (0,0)}\frac{x+y}{\sqrt{x^2+y^2}}$ . I tried to do couple of algebraic manipulations, but I didn't reach to any conclusion.  Thanks a lot.


I read upon  Gambler’s Ruin problem and encountered this interesting question. Consider a simple random walk on $\{0, 1, \ldots, N\}$ with absorbing barriers at $0$ and $N$. What is the probability $u_k$ that the walk is absorbed at $N$ if it begins at a point $k$, $0 \leq k \leq N$?  If the question doesn't indicate anything, does it mean this is symmetric? If so, would it be $u_k=\left(\frac{1}{2}\right)^{(N-k)}$?


I would like to change the color of some SVG pictures and then save them as PNG images. I have installed GIMP. I am running Ubuntu 14.04.  How can I do that?


How can I tell whether a mathematics journal seems reputable?

There are some general questions on this site about judging the reputability of journals in general:     and     I am interested in answers specific to mathematics, that may not have been raised in the other questions.  I received the following email from the "American Journal of Pure and Applied Mathematics" ten days after submitting a paper online. How can I tell whether this is a reputable journal? In general, how can I tell whether a mathematics journal is reputable?      Dear Authors,      On behalf of the Chief Editor of the “American Journal of Pure and Applied Mathematics” we are happy to inform you that your article entitled ‘A possible approach proof to proof the Riemann Hypothesis” is accepted for publication in (Jan-June 2015).      Please send DD/Cheque for US $ 250.00 payable to ‘ Vijay Kumar Jha ‘ to our address.      Our address:   Vijay Kumar Jha   Managing Editor   c\o. ACADEMIC RESEARCH JOURNALS (INDIA)      4383/4A, Ansari Road, Darya Ganj, New Delhi-110002      (M) 08826561892      We thank you very much for your contribution and encourage you to continue submitting your future.      Yours sincerely,


My TeXShop has been acting out: I haven't been able to open files with it. I was able occasionally to open document class files, but I had no luck whatsoever with beamer files. I can open and compile all the files using TeXMaker. I've tried reinstalling the entire MacTeX package twice but the problem persists (I'm using the latest TeXShop and the latest Sierra on Mac). Someone from comp.text.tex suggested that I need to find and remove TeXShop's configuration file, but I don't know how. Any help would be appreciated.


I set this new command:  \newcommand{\dd}{{\rm d}}   I want to set the same command but now in a generic way. Something like that:  \newcommand{\##}{{\rm #}}   How to do that?  Edit: The new command that I set (\newcommand{\dd}{{\rm d}}) only works for the letter d right?  I want to write the same new command but now working with any letter.


Given the sides of a triangle a, b, c, prove that $$a^2b(a-b)+ b^2c(b-c)+ c^2a(c-a)\geq 0$$   I can't seem to figure out how to simplify it. I assumed that $a$ is greatest out of the three, but I can't seem to make any headway.


Check if an element is visible in javascript

Hi guys:)How can I see what of ten elements is visible in viewport?


Do Cantor's Theorem and the Schroder-Bernstein Theorem Contradict?

I am confused as to how Cantor's Theorem and the Schroder-Bernstein Theorem interact. I think I understand the proofs for both theorems, and I agree with both of them. My problem is that I think you can use the Schroder-Bernstein Theorem to disprove Cantor's Theorem. I think I must be doing something wrong, but I can't figure out what. Can someone tell me where I am going wrong? Here's how I think I can prove that the set of all natural numbers has the same cardinality as its power set. Cantor's Theorem says that the power set of any set A has greater cardinality than A. Specifically, the set of all natural numbers, $\mathbb{N}$, is countably infinite, while its power set $P(\mathbb{N})$ is uncountably infinite. The Schroder-Bernstein Theorem says that, for two sets $A$ and $B$, if there exist one-to-one functions $f:A\mapsto B$ and $g:B \mapsto A$, then sets $A$ and $B$ have the same cardinality. I will try to use this to prove that the set of all natural numbers N has the same cardinality as its power set $P(\mathbb{N})$.  I need to prove that there exist one-to-one functions $f:\mathbb{N}\mapsto P(\mathbb{N})$ and $g:P(\mathbb{N})\mapsto \mathbb{N} $   $f:\mathbb{N}\mapsto P(\mathbb{N})$   Define $f:\mathbb{N}\mapsto P(\mathbb{N})$, $n\mapsto f(n)=\{n\}$  For each output $f(n)$, there can only be one n corresponding to $f(n)$, so $f$ is a one-to-one function.   $g:P(\mathbb{N})\mapsto \mathbb{N} $   Define $g:P(\mathbb{N})\mapsto \mathbb{N} $ as follows  Each element of $P(\mathbb{N})$ is a subset of $\mathbb{N}$, as represented by $\{{a}_{1},{a}_{2},\dots ,{a}_{k}\}$ where ${a}_{1},{a}_{2},\dots ,{a}_{k}$ are elements of $\mathbb{N}$  For each element $s=\{{a}_{1},{a}_{2},\dots ,{a}_{k}\}$ of $P(\mathbb{N})$, the elements of $s=\{{a}_{1},{a}_{2},\dots ,{a}_{k}\}$ are ordered from lowest to highest, so that ${a}_{1}<{a}_{2}<\dots <{a}_{k}$. The order of a set does not matter, so this can be done without creating a new set.  For each element $s=\{{a}_{1},{a}_{2},\dots ,{a}_{k}\}$ of  $P(\mathbb{N})$, $g(s)={{p}_{1}}^{{a}_{1}} *{{p}_{2}}^{{a}_{2}} * ... * {{p}_{k}}^{{a}_{k}}$, where ${p}_{1},{p}_{2},...,{p}_{k}$ are each the $k$th prime number. Ex. ${p}_{1}=2, {p}_{2}=3, {p}_{3}=5,\dots$  $P(\mathbb{N})$ contains the empty set, so $g(\emptyset)=0.$  The set of all prime numbers is countably infinite, so it has the same cardinality as the largest element of $P(\mathbb{N})$, which is $\mathbb{N}$.  Each output $g(s)$ is the prime factorization of some number n. Each number n has a unique prime factorization, so there is only one s in  $P(\mathbb{N})$ whose $g(s)$ is the prime factorization of n.  Since the elements of $s=\{{a}_{1},{a}_{2},\dots ,{a}_{k}\}$ are ordered from lowest to highest, ${a}_{1}$ is the only element of $s$ that can be $0$. Thus, ${p}_{1}=2$ is the only prime number that can have an exponent of 0 in the output. Thus, it is impossible for any set $s$ in  $P(\mathbb{N})$ to have the same output $g(s)$ as a set of different length in $P(\mathbb{N})$ . In other words, it is impossible to add or remove an element of s to create a new set ${s}_{2}$ so that $g(s)=g({s}_{2})$.  Every element $s$ of  $P(\mathbb{N})$ has a unique output $g(s)$, so $g:P(\mathbb{N})\mapsto \mathbb{N} $ is a one-to-one function.  So $f:\mathbb{N}\mapsto P(\mathbb{N})$ and $g:P(\mathbb{N})\mapsto \mathbb{N} $ are both one-to-one functions.  So $\mathbb{N}$ and  $P(\mathbb{N})$ have the same cardinality.  I'm fairly certain that both Cantor's Theorem and the Schroder-Bernstein Theorem are correct, so where does my proof go wrong?


I'm trying to install Ubuntu to USB so I can use it like a fully functional, persistent OS on multiple computers if need be (also, I am planning on switching my HDD soon).  I've tried mounting the official Live/Installer Ubuntu distro to the USB with rufus, but once I booted it up, if I try installing Ubuntu, it will only recognize my HDD partitions, but not the USB drive.  Next, I've tried using Unetbootin, but after installing that one I once again got a live USB, not a full Ubuntu install.   Do you have any suggestions on how I could install it directly to the flashdrive from my PC without needing a spare DVD/USB?  Before marking it as a duplicate, please read the question you're marking this as a duplicate of and the answer. I specifically said those sollutions do not work, and presented another issue.


What are the consequences of "copying" a data set for OLS?

Suppose I have a random sample $\lbrace X_i, Y_i\rbrace_{i=1}^n$. Assume this sample is such that the Gauss-Markov assumptions are satisfied such that I can construct an OLS estimator where  $$\hat{\beta}_1^{OLS} = \frac{\text{Cov}(X,Y)}{\text{Var(X)}}$$ $$\hat{\beta}_0^{OLS} = \bar{Y} - \bar{X} \hat{\beta}_1^{OLS}$$  Now suppose I take my data set and double it, meaning there is an exact copy for each of the $n$ $(X_i,Y_i)$ pairs.  My Question  How does this affect my ability to use OLS? Is it still consistent and identified?


Hive Jdbc connection errors with NoClassDefFoundError

I am writing Jdbc program to connect with hive database but I am getting error as:     Exception in thread "main" java.lang.NoClassDefFoundError:   org/apache/hadoop/conf/Configuration  at   org.apache.hive.jdbc.HiveConnection.createUnderlyingTransport(HiveConnection.java:418)     at   org.apache.hive.jdbc.HiveConnection.createBinaryTransport(HiveConnection.java:438)     at   org.apache.hive.jdbc.HiveConnection.openTransport(HiveConnection.java:225)     at   org.apache.hive.jdbc.HiveConnection.(HiveConnection.java:182)     at org.apache.hive.jdbc.HiveDriver.connect(HiveDriver.java:107)     at   java.sql.DriverManager.getConnection(DriverManager.java:571)  at   java.sql.DriverManager.getConnection(DriverManager.java:215)  at   com.nucsoft.client.HiveJdbc.main(HiveJdbc.java:31)


I want to start using QGIS. I have worked in ArcGIS but I would like to start learning QGIS online.   Any suggestions for good online courses (hopefully free or not very expensive)?


BNT162b2 mRNA Covid-19 Vaccine efficacy after 1st dose - explain the statistics

Pfizer's paper () published recently states the following in the Efficacy subsection of the Results section:  Between the first dose and the second dose, 39 cases in the BNT162b2 group and 82 cases in the placebo group were observed, resulting in a vaccine efficacy of 52% (95% CI, 29.5 to 68.4) during this interval and indicating early protection by the vaccine, starting as soon as 12 days after the first dose.  Can anyone explain in simple terms the calculation of 52%? I am guessing that this number was obtained from:  But why is that the calculation? Does it depend on the fact that the vaccine and placebo groups were in equal numbers, such that by observing 82 COVID-19 cases in the placebo group, we match 82 subjects in the vaccine group, and since only 39 confirmed cases were observed in the vaccine group, the authors conclude that the "complementary (to 82)" 43 subjects did not become sick, and thus the vaccine is efficient in 52% of the subjects?


proving of inequality $(n!)^2 \leq n^n\cdot n!\leq (2n!)$, where $n\in \mathbb{N}$

How can we prove the inequality $(n!)^2 \leq n^n\cdot n!\leq (2n!)$, where $n\in \mathbb{N}$  $\bf{My \; Try}$::  $1\leq n$  $2\leq n$  $3\leq n$  ....  ....  $n\leq n$  So $1\cdot 2 \cdot 3 ..n \leq n^n$  So $n!\leq n^n\Rightarrow (n!)^2 \leq n^n\cdot n!$  But  did not understand how can we prove $n^n\cdot n! \leq (2n!)$  Help me  Thanks


I have an image that is Base64 encoded. What is the best way to decode that in Java? Hopefully using only the libraries included with Sun Java 6.


How can I convert multiple faces of an object to light?

I have create this spiral LED lamp.  The cylindrical part of spiral has six faces.  Four of them (back) are the non-transparent part and the rest two (front) supposed to be the plastic cap of the LED strip.  At those front faces I have add a material with an emission surface so to look like lit LED strip.  What I want to do is to make all those front faces to shed light to my scene. But not just to look glowed like first image. Is that possible?