I am going through a basic course on complex analysis. I have a problem in understanding the following. E $\subset\mathbb{C}$ is defined as $$E := \{z\in\mathbb{C}:\vert z+i \vert = 2\vert z\vert \}$$ I want to know if this set is connected, closed, bounded but I do not know how to sketch this set or visualize it.

These usually aren't too bad but I had difficulties thinking of what the set  $$\{z\in\mathbb{C}:|z+i|=2|z|\}$$ looks like in the complex plane. I got as far as  $$|z+i|=2|z|\Rightarrow \sqrt{(z+i)(\overline{z+i})}=2z\overline{z}\Rightarrow  \sqrt{z\overline{z}+i\overline{z}-iz+1}=2z\overline{z}\\ \Rightarrow z\overline{z}-i(z+ z\overline{z})+1=4z\overline{z}\Rightarrow 3z\overline{z}=1-i2\Re(z)$$  And rearranging a bit I guess I can see that $z\overline{z}+\frac{2i\Re(z)}{3}=1/3$. If there weren't that second term on the left, this would be clear, but I am not sure how to think about the dependence on the real part of $z$ here.   Having graphed in wolfram, I know this is just a circle of radius 2/3 centered at $i/3$, but I would appreciate help with the thought process.


A watch not worth a penny was being sold there.    In this sentence, do I have to, must and should put "that is" like this?     A watch that is not worth a penny was being sold there.

When I write something like this:     I am a man that is doing these things.   Is it correct to shorten it like this?     I am a man doing these things.   And does it require commas?


Today, in my high school physics class, we had an introductory class on electromagnetism. My teacher explained at some point that an object with a very high speed (he said it started to get somewhat clearly noticable when travelling at 10% of the speed of light) will gain mass, and that that's the reason why you can't go faster than light. One of my classmates then asked, why is this so? Why does an object with higher speed gain more mass? This of course is a logical question, since it is not very intuitive that a higher speed leads to a higher mass. My teacher (to my surprise (responded saying that it is a meaningless question, we don't know why, in the same way we don't know why the universe was created and those kind of philosophical questions. I, being interested in physics, couldn't believe this, I was sure that what he said wasn't true. So after a while of thinking I responded saying: Can't we describe it with Einstein's $E=mc^2?$ If an object gains speed, he gains more (kinetic) energy. With this equality we see that the more energy an object gets, to more massive it becomes. He then replied saying that this formula is used for different cases, whereupon he gave a vague explanation as to when it is used. He gave me an example to show what I said was incorrect; when a car goes from $10 m/s$ to $40m/s$, according to what I said we would see a big increase in mass, and we don't (this sounded logical to me). So here I am, with the following questions:  Why does an object with a higher speed have more mass (than the same object with a smaller speed)?  When is $E=mc^2$ used and why is my argument incorrect in explaining this phenomenon?

I learned recently that when an object moves with a velocity comparable to the velocity of light the (relativistic) mass changes. How does this alteration take place?


There have been many questions in the past about choosing an affiliation to write on your papers. This one has a nuance that is a bit different from having two jobs.  I am currently between two jobs (PhD student and postdoc) and currently not academically affiliated to either. I am currently writing a paper and I am trying to figure out if I put my PhD affiliation or my postdoc affiliation.  The reason for the PhD affiliation is because a lot of the work was done there.  The reason for the postdoc affiliation is because then anyone could contact me for correspondence with respect to the paper.    I feel there must be a hard and fast rule to this, so I was hoping someone could enlighten me.   Thanks!

I am moving from one job to another (postdoc to tenure track) this summer and I have papers in several stages of being written, these go from handwritten notes with all the necessary arguments to under revision at a journal. All the papers will have my new contact information put on them but where is the line for changing affiliation? It seems obvious to me that the one that is still in the handwritten notes stage will get the new affiliation and that the ones under revision won't. So somewhere in between is a line.   Where is it?  There are some similar questions so far (see  and  but they do not seem to be quite the same situation since I am not changing fields and the appointments are not concurrent.


Let $G$ be a finite group, and $H$,$K$ be subgroups. Then we can form the set $$HK = \{hk: h \in H, k \in K\}$$ It is well known that $HK$ is a subgroup of $G$ if and only if $HK=KH$. If $H \cap K = \{e\}$, then we clearly have $|HK| = |H||K|$ (indeed, the group multiplication $H \times K \to HK$ is a bijection).  On the other extreme, if $H \subset K$ then $|HK| = |K|$. In general we have the formula $$|HK| = \frac{|H||K|}{|H \cap K|}$$  which quantifies the idea that we "$HK$ collapses in proportion to how many elements $H,K$ share". I'm trying to get a bit more intuition for this fact.  by which we establish a bijection between the sets of cosets $HK/K$ and $H/(H\cap K)$, but it wasn't "manual" enough for me (that is to say, I'm willing to believe that it's an enlightening proof, to someone who is more savvy with cosets).  One idea for an argument I had was counting: if we seek to prove $|HK||H \cap K| = |H||K|$ then it's attractive to try to show that every distinct element of $HK$ obtained by writing $g = hk$ is multiply counted $|H \cap K|$ times. Indeed, suppose that $h_{1}k_{1} = h_{2}k_{2}$. Then we obtain the element $h_{1}^{-1}h_{2} = k_{1}k_{2}^{-1} \in H \cap K$. Then I get a bit stuck, because I want to show the duplicate elements biject with $H \cap K$ but I can't tell how. Of course, it might not be possible, but my intuition says maybe.    Any of the following would constitute a helpful answer (and be greatly appreciated!):   A bit of exposition into why the coset-based argument is an intuitive one to make (especially without knowing the answer in advance) Some help finishing off the argument I've tried to start   A oonvincing reason the argument I've started is hopeless

Let $H$, $K$ be subgroups of $G$. Prove that $o(HK) = \frac{o(H)o(K)}{o(H \cap K)}$.  I need this theorem to prove something.


Why is ArcMap 10.5.1 search window not showing properly?   Out of ca 50 times opening ArcMap, only twice or so it looked like in previous versions, i.e. there was possibility to work with that - e.g. enter a name of function and search for it...    I am using Windows 7 Professional.     I have -renamed ESRI folder, also in registry, not helped! -deleted Normal.mxt, no change! -chosen "repair" in instalation file window, also not helped!

I can no longer search for tools, etc using the Search window in ArcMap i.e. Windows | Search doesn't work and nor does ctrl + f.   I thought updating my student license would do the trick but after doing so it's still the same. I have also tried to fix it by deleting Normal.mxt but that didn't work either.  I read somewhere that ArcMap can sometimes misbehave because of problems related to the pc user account.   I may accidentally have shut down my computer the wrong way last week and before I was properly logged off (by pulling the plug too early).  What could be the cause of this and how may I fix it?   My version of ArcMap is 10.5.0.6491.


error when installing any packages.. pls help.. thanks in advance..  been trying to solve this for days now.. still can't solve it.. Already tried       $ sudo apt-get update     $ sudo apt-get upgrade     $ sudo apt-get autoremove     $ sudo apt-get clean   etc..  Preconfiguring packages ... Selecting previously unselected package libglade2-0:amd64. dpkg: unrecoverable fatal error, aborting:  reading files list for package 'linux-headers-3.8.0-19': Input/output error E: Sub-process /usr/bin/dpkg returned an error code (2)

I have been running Ubuntu 12.04 for the past few weeks. I recently tried to download and install some files through the Update Manager. It located a few files, downloaded them, but then failed to install them. It gave the error:  installArchives() failed: (Reading database ...  (Reading database ... 80% dpkg: unrecoverable fatal error, aborting:  reading files list for package 'libasn1-8-heimdal': Input/output error   I tried using apt-get upgrade but a similar error was produced:  Reading package lists... Done Building dependency tree        Reading state information... Done The following packages will be upgraded:   icedtea-6-jre-cacao icedtea-6-jre-jamvm openjdk-6-jre openjdk-6-jre-headless   openjdk-6-jre-lib 5 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/34.6 MB of archives. After this operation, 1,024 B of additional disk space will be used. Do you want to continue [Y/n]? y (Reading database ... 80% dpkg: unrecoverable fatal error, aborting:  reading files list for package 'libasn1-8-heimdal': Input/output error E: Sub-process /usr/bin/dpkg returned an error code (2)   Any help would be greatly appreciated. Thanks in advance.  Edit: Here's some extra information that may be useful. My original problem was that the Ubuntu Software Centre would not open. I found that the Update Manager and Synaptic Package Manager also failed to open. They all gave an error along the lines of:   "installArchives() failed: dpkg: error: reading package info file '/var/lib/dpkg/available': Input/output errorError in function:"   After much googling I seemed to fix that problem as the package managers would open again. When I then tried to download and install any updates from the Update Manager I got the error at the beginning of this post.


I have built and tested a computer application, which involved two participant groups (Group-A with existing knowledge of databases and Group-B without knowledge of databases).  I was required to apply test of statistical tests to determine if the rating and perception of built application was same among both groups. I used the system log file and questionnaire tools for collecting information used for histograms, means, skewness and kurtosis values.  The question I am looking to ask, Is the use of statistical tests (histograms, means, skewness and kurtosis) values used for measuring the differences of data / rating / perception between both groups were appropriate?

I have built and tested a computer application, which involved two participant groups (Group-A with existing knowledge of databases and Group-B without knowledge of databases). I was required to apply statistical tests to determine if the perception and rating given to the application was same among both groups (based on the data recorded in the form of questionnaires). The participants from both groups filled out questionnaires (with 10 questions to rate based on Likert scales) to rate the system based on their experience during testing it.   Is the use of statistical tests (histograms, means, skewness and kurtosis), used for measuring the differences of data / rating / perception between both groups appropriate? What I am trying to see is that if / how much participants' ratings in group A differ from the ratings given by the participants in group-B, for each question of the questionnaire.


I am trying to retrieve BIOS Event log so I can see low level hardware errors such as thermal events from recent model Dell Laptops. I know they have their own tool to do this but it doesn't do specifically what I need.   I know I can get some high level BIOS data using Win32_BIOS via WMI however I don't see the BIOS event log data that way which is what I am after. Anyone know how to get this or what WMI branch this is under in C# via Winforms (.Net 4.0) ?  (PS. Please don't suggest an alternative tool or discussing it with Dell as those options have already been explored and are not a direction I want to go. Thanks)

I want to be able to pull in the error log from BIOS across a network. Looking at Win32_BIOS in MSDN I did not see anything defining the error log. Would love to do this in C# with WMI, but am open to suggestions. Is it possible?  Win32_BIOS does not have a property (don't know if that is the right term) that contains the BIOS error log. Is there a library, API, etc. that I can use to pull this information locally or from the network?


I want to draw a tree but I want the nodes to be able to have multiple lines and specific width. I have searched about trees but all of them consist of a single line in each node. From what I have found Tikz seems nice but I have no idea about tree packages. How can I achieve what I want?

I am trying to get Rachel Brown all on one line, and below Rachel Brown - three branches that say Mary Brown, Laura Brown and Emma Brown. I am also trying to get ages to show below each name, for example directly below Hannah Brown it needs to say (Age: 23), etc. Many Thanks!  \documentclass{article} \usepackage{tikz-qtree}  \begin{document} \tikzset{edge from parent/.style= {draw, edge from parent path={(\tikzparentnode.south) -- +(0,-8pt) -| (\tikzchildnode)}}, blank/.style={draw=none}} \begin{tikzpicture} \matrix { \node{\Tree   [.{Hannah Brown}   [.Rachel Brown ]]};\\ };            \end{tikzpicture}  \end{document}


I need a formula that would copy all the cells from column B if there is today's date in any cell next to (same row). The copied cells would go to empty column I, each cell under the next.

My spreadsheet has "variant" names in Column B, and relevant dates in adjacent columns C-H on the same row. I have included a screenshot below I want to create formula that will display a list "variant" names when "todays's date" (today()) matches a date in the adjacent Columns C-H on the same row as the "variant" name. The list would be displayed in Column I. For example:  If today's date is, say, 26 March 2021 then (based on the data in the screenshot below) the list of "variants" would be those five names circled in red.  When today's date is 27 March 2021, the list of variants would automatically update to include only those five names with a value of 2021-03-27 (in the same row as the name) in one of the adjacent Columns C-H.   Normally some kind of vlookup/hlookup/lookup might do the trick, but this has to evaluate 6 date values and return the "variant" name from a column to the left of the date columns. Maybe a query or filter might be better since they could also apply to any new rows of data.


I have simple app where I have input where I can upload pdf file and  <input (change)="upload($event)"        multiple        type="file"/>  <object [data]="file" type="application/pdf">     <embed [src]="file" type="application/pdf" /> </object>   in upload function:  upload(event) { this.file = event.target.files[0]; }   How can I display preview of that file?

What is the recommended way to embed PDF in HTML?   iFrame?  Object?  Embed?   What does Adobe say itself about it?  In my case, the PDF is generated on the fly, so it can't be uploaded to a third-party solution prior to flushing it.


I wrote a simple Perl script try to make a connection to remote server (SSH) and run command. But came up some message I don’t what is about.  Apache Log:  Can't locate Net/SSH/Perl.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/s BEGIN failed--compilation aborted at (eval 4) line 3.   I tried find the file  find: `perl.pm': No such file or directory   I installed NET::SSH::Perl , log:    root@server:/usr/include# cpan install Net::SSH::Perl Loading internal null logger. Install Log::Log4perl for logging messages CPAN: Storable loaded ok (v2.27) Reading '/root/.cpan/Metadata'   Database was generated on Fri, 10 Feb 2017 11:17:03 GMT CPAN: Module::CoreList loaded ok (v3.07) Net::SSH::Perl is up to date (2.01).

I’ve got several Perl modules installed on my hosting machine in ~/perl, how do I add them to Perl module path? Setting PERL5LIB or unshifting the paths to @INC surely works, but the environment variable does not help when running as a CGI script and the @INC way is not very portable. Is there a better way? This has to be a common problem, am I missing something?


I have this combinatoric question which I can't figure out. In how many ways can we sit 12 men and 12 women on a bench where no 2 women sit next to each other. The answer is : $ 13! \cdot 12! $ but my answer was $12! \cdot 12! \cdot 2 $ and I don't understand why my answer is wrong. I tried to look at a smaller example where there are only 2 men and 2 women with same limitations and coudln't count more then 8 ways which are $2! \cdot 2! \cdot 2 $ so I realy don't know how to proceed. Thank you

There are $12$ women and $12$ men. How many ways are there to sit them all on a bench where no woman can sit next to another woman?  Thank you.


If I am given some random date, then I need to check if that date really exists or not and then display true or false. I need to return false for both the dates 32-11-2010 and  31-02-2010 because the month of february doesn't contain 31st. How do we do this in Java?

I find it curious that the most obvious way to create Date objects in Java has been deprecated and appears to have been "substituted" with a not so obvious to use lenient calendar.  How do you check that a date, given as a combination of day, month, and year, is a valid date?  For instance, 2008-02-31 (as in yyyy-mm-dd) would be an invalid date.


Let $G$ be an abelian finite non trivial group and $p$ a prime number which devises o(G). We denote $H$ the set of non trivial subgroups of $G$. Could you please help me to show that if there exists $M\in H$ such that $p$ devises $o(M)$  then there exists $g\in G$ of order $p$. Thanks in advance

I am reading the Dummit and Foote's proof of Cauchy's theorem for abelian groups. On the highlighted line, how do you conclude from $y\notin N$ and $y^p\in N$ that $\langle y^p \rangle \neq \langle y \rangle$ and that $|y^p|<|y|$?     Proposition 21.   If $G$ is a finite abelian group and $p$ is a prime dividing $|G|$, then $G$ contains an element of order $p$.      Proof:   The proof proceeds by induction on $|G|$, namely, we assume the result is valid for every group whose order is strictly smaller than the order of $G$ and then prove the result valid for $G$ (this is sometimes referred to as complete induction).   Since $|G| > 1$, there is an element $x \in G$ with $x \neq 1$.   If $|G| = p$ then $x$ has order $p$ by Lagrange’s Theorem and we are done.   We may therefore assume $|G| > p$.      Suppose $p$ divides $|x|$ and write $|x| = pn$.   By Proposition 2.5(3), $|x^n| = p$, and again we have an element of order $p$.   We may therefore assume $p$ does not divides $|x|$.      Let $N = \langle x \rangle$.   Since $G$ is abelian, $N \trianglelefteq G$.   By Lagrange’s Theorem, $|G/N| = |G|/|N|$ and since $N \neq 1$, $|G/N| < |G|$.   Since $p$ does not divide $|N|$, we must have $p \mid |G/N|$.   We can now apply the induction assumption to the smaller group $G/N$ to conclude it contains an element $\bar{y} = yN$, of order $p$.   Since $y \notin N$ ($\bar{y} \neq \bar{1}$) but $y^p \in N$ ($\bar{y}^p = \bar{1}$) we must have $\langle y^p \rangle \neq \langle y \rangle$, that is, $|y^p| < |y|$.   Proposition 2.5(2) implies $p \mid |y|$.   We are now in the situation described in the preceding paragraph, so that argument again produces an element of order $p$.   The induction is complete.      (Original image .)


The problem asks to show that $$f(x,y) = \left\{ \begin{align} \frac{x^3y^2}{x^4+y^4}, & (x,y) \neq (0,0), \\ 0, & (x,y) = (0,0), \end{align} \right.$$ is continuous at the origin, however it has resisted my bravest efforts. I have attempted using $x^4+y^4 \geq y^4$ and therefore $$\left\vert \frac{x^3y^2}{x^4+y^4} \right\vert \leq \left\vert \frac{x^3}{y^2} \right\vert$$ and similar strategies but they have failed. Trying to disprove it and see if it's discontinuous has only strengthened the belief that it's continuous.

Suppose a function $f$ is defined as follows:   $$f(x,y)=\begin{cases} \frac{x^3y^2}{x^4+y^4}&\text{ when }(x,y)\neq(0,0),\\0 & \text{ when }(x,y)=(0,0).\end{cases}$$  Is this function continuous at $(0,0)$? How is this shown? I've tried considering limits for different $y=g(x)$ functions and I am unable to find a counterexample. But I do not see how to prove continuity in general.


I know this question is answered, here         httpsss://math.stackexchange.com/questions/507451/suppose-that-p-%E2%89%A5-q-%E2%89%A5-5-are-both-prime-numbers-prove-that-24-divides-p2  But when I was doing the question ,I thought that  "Can I make difference of square of $2$ primes a product which is divisible by $4!$ "  While doing it, some examples were just trying to show me something but I don't know what the examples are shown in the pic.

Let $p>3$ be a prime. Prove that $24 \mid p^2-1$.   I know this is very basic and old hat to many, but I love this question and I am interested in seeing whether there are any proofs beyond the two I already know.


I am asking out of curiousity, because I believe there are many questions that should be there but they aren't.

I really like the , where certain questions from the Stack Exchange Network are presented, along with a hotness rating that is described as "arbitrary" in its tooltip. Such questions also appear randomly on the sidebar on sites across the network, under the heading "Hot Network Questions". How do these arbitrary hotness points work, and how are they used to select questions to appear in those lists?


I want to switch Power Between a AC/DC adapter which is supplying power to the circuit when AC power is On and when power loss power the circuit using 12V 7Ah Battery. AC/DC adapter is rated 12V 1Ah.   First I thought switch power with a Relay and Arduino with a sensor to monitor AC power loss. but I Came to know there is a better way using a Diode Oring.  Please explain how to use diodes to switch between power Supplies and what diodes to use for this?  I saw that in a article, to Diode ORing to work main supply should greater than backup. so in my case both the main supply and backup supply is 12V.   so Diode ORing option will not work as expected?

I want to make a device that allows the user to switch between two different power sources (a wall mount and batteries).   I could perform this circuit using two DPDT switches, but I would need to switch the two switches each time I want to change sources. Is there a simpler way to perform this function without using relays?  Here's a schematic of my device as a reference:


Is it possible to do a custom object nested query on a standard object?  Like so:  [SELECT (SELECT Id, Case__c FROM Accounting_Instructions__c WHERE Accounting_Complete__c = TRUE AND Case__r.Id =:currentPageId), AccountId, CaseNumber FROM Case WHERE AccountId = :strAccountId AND Id IN :accountIds];    There is a relationship between Accounting_Instructions__c and Case (similar to Task and Case). I know you can do two standard objects and use the . An example of this is in this post: .   Because of this format my initial thought would be to change Accounting_Instructions__c to  Accounting_Instructions (like Task to Tasks) but this doesn't make sense because it's a custom object so I have no idea how Salesforce would understand this naming convention.   All of the documentation I am finding is examples of standard to standard object or custom to custom objects. Any advice?

Say I have a master-detail relationship between two objects, Schematic__c and Part__c.  I can SOQL query the master from the detail: [SELECT Schematic__r.Name FROM Part__c]  If I'm building a query from strings, I resolve the schema name, for example in a managed package:  SObjectType.Part__c.Fields.Schematic__c.Name //gives me 'ns__Schematic__c'   But when traversing into the master object, the __r relationship suffix is what I need to surface. I've toyed around with the obvious Schema.SObjectType variations but I'm not having much luck:  SObjectType.Part__c.Fields.Schematic__r.Name //Schematic__r is not a field of ns__Symbol__c   What's the correct way to resolve the ns__Schematic__r.Name token without replacing the suffix?


I couldn't really find anything on this, but it has been bugging me for a while.  Say for example, you have the following dialogue:     'I'll let Mr. Hall know.'   If you want to emulate "dropping the H" (similar to dropping the "A" and "D" in "fish 'n' chips"), does the first letter after the apostrophe have to be capitalised:     'I'll let Mr. 'All know.' vs. 'I'll let Mr. 'all know.'

A new Victorian-set British novel begins sentences containing h-dropping with lower-case e's, as in " 'e took my money, 'e did." This seems incorrect but I'm at a loss to find the rule.


I am not rendering any results. This is my template.php:  function fueldeluxe_theme($existing, $type, $theme, $path) {   $items = array();    /**    *  Account edit Forms    */    $items['user_profile_form'] = array(     'render element' => 'form',     'template' => 'user-profile-form',     'path' => drupal_get_path('theme', 'fueldeluxe') . '/templates'   );    return $items;  }  function fueldeluxe_preprocess_user_profile_form(&$variables) {   $variables['account'] = drupal_render($variables['form']['account']);   $variables['picture'] = drupal_render($variables['form']['picture']); }   This is my user-profile-form.tpl.php:

     <?php echo $picture; ?>

     <?php echo $account; ?>

      As you can see I'm trying to load the user profile field forms. However I'm not able to render any results. The page loads okay when I add dummy text but no account field forms.  Do I need a module for this to work?  Also what would the variable look like for calling the custom field added to a user?

I am not rendering any results. This is my template.php:  function fueldeluxe_theme($existing, $type, $theme, $path) {     /**     *  Account edit Forms     */     $items = array();     $items['user_profile_form'] = array(         'render element' => 'form',         'template' => 'user-profile-form',         'path' => drupal_get_path('theme', 'fueldeluxe') . '/templates'     );     return $items;  }  function fueldeluxe_preprocess_user_profile_form(&$variables) {     $variables['account'] = drupal_render($variables['form']['account']);     $variables['picture'] = drupal_render($variables['form']['picture']); }   This is my user-profile-form.tpl.php:

         <?php echo $picture; ?>

         <?php echo $account; ?>

    As you can see I'm trying to load the user profile field forms. However I'm not able to render any results. The page loads okay when I add dummy text but no account field forms.


I have a JSON file that is a mess that I want to prettyprint. What's the easiest way to do this in Python?  I know PrettyPrint takes an "object", which I think can be a file, but I don't know how to pass a file in. Just using the filename doesn't work.

Is there a (Unix) shell script to format JSON in human-readable form?  Basically, I want it to transform the following:  { "foo": "lorem", "bar": "ipsum" }   ... into something like this:  {     "foo": "lorem",     "bar": "ipsum" }


Good evening guys, I am currently trying to figure out how to add a custom pagebreak inside a figure environment containing multiple subfloats (2 columns) using the subfig package, e.g.: \begin{figure}     \centering     \subfloat[][1] {         \centering         \includegraphics[width=.45\linewidth]{...}     }     \qquad     \subfloat[][2]{         \centering         \includegraphics[width=.45\linewidth]{...}     }      \subfloat[][3]{         \centering         \includegraphics[width=.45\linewidth]{...}     }     \qquad     \subfloat[][4] {         \centering         \includegraphics[width=.45\linewidth]{...}     }      \subfloat[][5]{         \centering         \includegraphics[width=.45\linewidth]{...}     }     \qquad     \subfloat[][6]{         \centering         \includegraphics[width=.45\linewidth]{...}     }      \subfloat[][7] {         \centering         \includegraphics[width=.45\linewidth]{...}     }     \qquad     \subfloat[][8]{         \centering         \includegraphics[width=.45\linewidth]{...}     }      \subfloat[][9]{         \centering         \includegraphics[width=.45\linewidth]{...}     }     \qquad     \subfloat[][10] {         \centering         \includegraphics[width=.45\linewidth]{...}     }     \caption{...}     \label{...} \end{figure}  I have tried inserting \pagebreak, \newpage, and \clearpage between figure 2 and 3 to split the figure across two pages, but none of them worked. Is this even possible? What is the best way to achieve this? Thank you all!

I have the following code for a Figure with 4 subfigures:  \documentclass{article} \usepackage{graphicx} \usepackage{caption} \usepackage{subcaption}  \begin{document}  \begin{figure}[b]     \centering     \begin{subfigure}[b]{\textwidth}         \includegraphics[width=\textwidth]{./plots/arm1.pdf}         \subcaption{$Q^{*}$ values for arm 1}         \label{fig:arm1}     \end{subfigure}     ~     \begin{subfigure}[b]{\textwidth}         \includegraphics[width=\textwidth]{./plots/arm2.pdf}         \subcaption{$Q^{*}$ values for arm 2}         \label{fig:arm2}     \end{subfigure}      ~     \begin{subfigure}[b]{\textwidth}         \includegraphics[width=\textwidth]{./plots/arm3.pdf}         \subcaption{$Q^{*}$ values for arm 3}         \label{fig:arm3}     \end{subfigure}      ~     \begin{subfigure}[b]{\textwidth}         \includegraphics[width=\textwidth]{./plots/arm4.pdf}         \subcaption{$Q^{*}$ values for arm 4}         \label{fig:arm4}     \end{subfigure}      \caption{$Q^{*}$ values for different arms}     \label{fig:arms} \end{figure}  \end{document}   This results in   But this way, the 4 subfigures are too large to fit on 1 page. I would like to split this over 2 pages, keeping the subcaptions a, b, ... How can I do this?


I want to read the manpage for the application cutechess, however I do not want to install it, so is there any way to get and read a manpage for a package without installing it? That is through the command-line and not a browser (a Terminal browser such as lynx does not count). This method should work for all packages and not be specific to cutechess though. I am running Ubuntu GNOME 15.04.

How can I get information about a package before installing it, from the terminal?  I mean something like man pages, but accessible even before the package is installed.


I am trying to create a plot in R and use knitr and latex to print that plot to a pdf. I think I am taking the correct steps: 1. save plot as .png in same folder as .tex file 2. write this into the latex file as includegraphics 3. run the knitr  However, the program is not recognizing/finding my recently created plot .png even though I checked that it is there in explorer.    This is my code in R to create the .png that seems to successfully create the .png file in my working directory (which is also where the .tex file is):  png("hab_pie.png", height=400, width=400) bp <- ggplot(aoi_HabTerr2, aes(x="", y=acres, fill=habitat)) + geom_bar(width=1, stat="identity") bp + coord_polar("y", start=0) dev.off()   This is the relevant code that is in my .Rnw document:  \documentclass{article} \usepackage{graphicx} \usepackage{geometry} \usepackage{fancyhdr}     %for headers,footers \usepackage{underscore}  %needed if any text has underscores \usepackage[utf8]{inputenc}  \usepackage[singlelinecheck=false]{caption}  \geometry{letterpaper, top=0.45in, bottom=0.75in, left=0.75in, right=0.75in}  \begin{document}  \includegraphics[width=\linewidth]{hab_pie}  \end{document}   I am getting this error:  LaTeX Error: File `hab_pie' not found.   And when I look in the folder, the file is present under the same name:

I am writing a LaTeX document with the apacite and graphicx package. The issue is when I include an image either using figure with an enclosed \includegraphics or \includegraphics by itself it shows the image with the file name to the side.  For example:              --------------             |             |             |    BOX 1    |               --------------- Error1.jpg   I do not want it to write Error1.jpg. Would show the image but it seems I do not have enough rep.  This is an example tex file to show the error (with Windows XP, using Miktex 2.8).  \documentclass[man]{apa} \usepackage{apacite} \usepackage{graphicx} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \begin{document}   \includegraphics{Example Error1.jpg} \begin{figure}[htb] \includegraphics{Example Error1.jpg} \caption{This is the caption of the figure.} \label{fig:fig2} \end{figure} \end{document}


I hava a table USER:  select t.* from user t; uid  uname 1    tom 2    jim 3    bob 4    lily   and table TOYS  select t.* from toys t; tid  uid  tdate 1    1    7/12/15 2    1    6/12/15 3    2    9/12/15 4    2    10/12/15 5    3    12/12/15   now I want   uid  tid   uname  tdate 1    2     tom    6/12/15 2    3     jim    9/12/15 3    5     bob    12/12/15 4          lily   what should I do?  (I use oracle database);

Table:   UserId, Value, Date.   I want to get the UserId, Value for the max(Date) for each UserId. That is, the Value for each UserId that has the latest date. Is there a way to do this simply in SQL? (Preferably Oracle)  Update: Apologies for any ambiguity: I need to get ALL the UserIds. But for each UserId, only that row where that user has the latest date.


I am at my wits end with this computer.  I bought and Acer Aspire 4752 with a fully loaded version of Windows 7 on it.   I prefer Ubuntu so I began to install 14.04 from USB. Got the error: [Errno 5] Input/output error  This is often due to a faulty CD/DVD disk or drive, or a faulty hard disk. It may  help to clean the CD/DVD, to burn the CD/DVD at a lower speed, to clean the CD/DVD  drive lens (cleaning kits are often available from electronics suppliers), to check  whether the hard disk is old and in need of replacement, or to move the system to a  cooler environment.  So I tried a different USB stick, same error.  Tried different versions of Ubuntu, got the same error.  I've used startup disk creator and Unetbootin to make start USB boot devices.    I can boot with the USB drive and run Ubuntu that way.  I even checked the hard drive using the tools in Ubuntu.  Everything was fine, except it said the hard drive was hot.  I tried a different hard drive.  Got same error above.   I ran a test with mem86, everything was fine.  No matter what I do, using the USB gives me the Errno5 error.  I then switched to using DVDs.   Now I keep getting an uncompression error when installing Ubuntu 14.04 or 12.04.  I can't figure out for the life of me why I get nothing but errors.  Can anyone help?

Today I downloaded Ubuntu for my laptop. It runs great from a bootable USB, but when I tried to install it, I got the following error message: The installer encountered an error copying files to the hard disk:  [Errno 5] Input/output error  This is often due to a faulty CD/DVD disk or drive, or a faulty hard    disk. It may help to clean the CD/DVD, to burn the CD/DVD at a lower   speed, to clean the CD/DVD drive lens (cleaning kits are often    available from electronics suppliers), to check whether the hard disk   is old and in need of replacement, or to move the system to a cooler   environment.     I tried everything to install it on my laptop including redownloading the Ubuntu ISO image, but nothing worked.


I saw a science fiction anthology series episode in which when a man manipulated by a doctor, I think a psychiatrist, slept and dreamed he would wake up to a world affected by what he had dreamed.  When I saw it, I looked it up and found that it was based on a book, and that a movie had also been made based on it.  I cannot remember the names of any of them.

First, a word about the format - I don't know whether this was a movie or a TV series, b/c I saw it aired in pieces on PBS back in the 1980s. I don't even recall if it was originally voiced in english, dubbed over, or subtitled. I'll just call it a movie for now.  The movie seemed to be set in Europe in what looked like the 1960's or 70's, where almost all the people were gone. The protagonist was probably a 20-something man, who routinely visited a psychiatrist. I think the protagonist also had a girlfriend, but most of the dialogs seemed to be between the man and the doctor.   It was kind of a mystery where all the people had gone, and I think the man was nominally seeing the doctor to cope with the stress of it all, or had amnesia and suspected he knew The Truth. However, it turns out that the doctor discovers that the man is somehow the key to the reality that the characters share, and during hypnosis sessions, discovers he can manipulate the man and thereby reality. To make it easier for himself, the doctor gives the man a code word to return the man to a hypnotic trance on command. The code word, I am positive, was 'Antwerp'.  I don't think I ever saw the end of this, but the 'truth' might have been that World War III was fought with neutron bombs, and that the man was actually just dreaming everything as he wandered around the city, dying. Or not. It would be nice to know how it turned out, but I don't even have the name of the show.


I use Ubuntu 18.04 and want to display images in terminal from a specified file name.I tried VIU and FIM, but they display the image in different windows. I want the image to displayed in the same window under some text.How can I do so?

This is a quick mockup I copy and pasted together. I imagine this being super cool and useful.  Does something like this exist already?


I am new to programming.When I find this strange result while I learning python.  >>> 10/-7 -2

Is there a benefit to using one over the other? In Python 2, they both seem to return the same results:  >>> 6/3 2 >>> 6//3 2


I woke up very early in the morning today to try and be more productive, and when I checked my phone there was a Venusaur nearby! I didn't hesitate to go outside and find him. I was a little disappointed when I did. He had 32 CP (sigh).   I have 4 more Bulbasaurs, my strongest with a 299 CP. Is powering up my Venusaur or waiting to find more Bulbasaurs to evolve the strongest one the ideal choice?   (I'm having a hard time finding Bulbasaurs) :/ By the way, I'm level 13

When activating the evolution for a caught Pokemon, it seems to amplify the Combat Power (CP). Thus it seems most beneficial to evolve your Pokemon with the highest CP, if you have multiple of the same kind.   But what I am not sure about is whether it makes an efficiency difference if you spend candies and dust to boost CP before evolving, to gain more from the amplification? Or is it more efficient to just evolve without spending, and then using the leftover candies afterwards, since they now give a bigger CP boost per candy?   I only tested with a Rattata so far, which gained +8 CP per candy before evolving, and +15 CP afterwards. I collected no numbers on the amplification efficiency though, and now ran out of materials for further testing.  Or maybe it is a balanced calculation and makes no difference at all? I would love to have some insight on that.    Some data I collected thus far: (GPC = CP gain per candy)  79 CP Weedle (GPC 6) evolved to: 84 CP Kakuna (GPC 6), evolved at 90 CP to: 297 CP Beedrill    Note: The max-CP "half circle" in the profile stayed filled roughly at the same relative position throughout the evolutions.


How can i write a file in PHP with encode ISO-8859-1?  Im using the function   $file = fopen("file.txt", "a");   When the file is created, it appears with encoding UTF-8 and i want it in ISO-8859-1.

Some of my script are using different encoding, and when I try to combine them, this has becom an issue.  But I can't change the encoding they use, instead I want to change the encodig of the result from script A, and use it as parameter in script B.   So: is there any simple way to change a string from UTF-8 to ISO-88591 in PHP? I have looked at utf_encode and _decode, but they doesn't do what i want. Why doesn't there exsist any "utf2iso()"-function, or similar?  I don't think I have characters that can't be written in ISO-format, so that shouldn't be an huge issue.


Which is the cardinality of the set of all functions $\mathbb{R} \to \mathbb{R}$ ?  For the relations in $\mathbb{R}$ I think the cardinality is the cardinality of $\mathcal{P(\mathbb{R^2})}$ , but I'm not sure.

How does one compute the cardinality of the set of functions $f:\mathbb{R} \to \mathbb{R}$ (not necessarily continuous)?


This question was asked in a quaifying exam for which I am preparing.  Let F $\subseteq \mathbb{C}$be the splitting field of $x^{7}-2$ over $\mathbb{Q}$and $z=e^{2\pi i /7}$, aprimitive 7th root of unity.  Then Find $[F:\mathbb{Q(z)}]$=a and $[F:\mathbb{Q}({2}^{1/7})]=b$ I have studied Field Theory from Thomas Hungerford and couldn't try any problems due to lack of time.So, I am not able solve it. splitting field is a field in which polynomial splits completely ie all its roots are linear and $({2}^{1/7})$ is one of the roots. But I am not able to use them in my question . Can you please help on how to tackle the problem. I know this is happening due to lack of problem solving. Thanks!!

I have this:  The splitting field of $x^p-2$ over $\mathbb{Q}$ is $\mathbb{Q}(\sqrt[p]{2},\xi)$ with $\xi=e^{{2\pi i}/p}$. $[\mathbb{Q}(\sqrt[p]{2})(\xi):\mathbb{Q}(\sqrt[p]{2})][\mathbb{Q}(\sqrt[p]{2}):\mathbb{Q}]=[\mathbb{Q}(\sqrt[p]{2})(\xi):\mathbb{Q}(\sqrt[p]{2})]\cdot p$ $\xi$ is a root of $x^{p}-1$. Then $min_{\mathbb{Q}(\sqrt[p]{2})}(e^{{2\pi i}/p})$ divides $x^p-1$. $x^p-1=(x-1)(x^{p-1}+x^{p-2}+\cdots +x+1)$ and $\xi$ is root of $(x^{p-1}+x^{p-2}+\cdots +x+1)$ therefore $min_{\mathbb{Q}(\sqrt[p]{2})}(e^{{2\pi i}/p})$ divides $(x^{p-1}+x^{p-2}+\cdots +x+1)$   According to me, it is true that $min_{\mathbb{Q}(\sqrt[p]{2})}(e^{{2\pi i}/p})=(x^{p-1}+x^{p-2}+\cdots +x+1)$ but  i dont'know proves it  (on another topic I saw that $min_{\mathbb{Q}}(e^{{2\pi i}/p})=(x^{p-1}+x^{p-2}+\cdots +x+1)$ (over $\mathbb{Q})$ but now I need to prove that it is irreducible over $\mathbb{Q}(\sqrt[p]{2})$  Let $\psi:\mathbb{Q}(\sqrt[p]{2},\xi)\to \mathbb{Q}(\sqrt[p]{2},\xi)$ automorphism such that for all $x\in \mathbb{Q},\, \psi(x)=x$.  I need find the extension of $\mathbb{Q}(\sqrt[p]{2})\to \mathbb{Q}(\sqrt[p]{2},\xi)$. Since $x^p-2=0$ implies  (on $\mathbb{Q}(\sqrt[p]{2},\xi)$) that $x\in \left\{\sqrt[p]{2},\sqrt[p]{2}\xi,\sqrt[p]{2}\xi^2,\ldots, \sqrt[p]{2}\xi^{p-1}\right\}$. By  a theorem, exists $p$ extensions (because exists $p$ rootS of $x^p-2=0$) This $p$ extensions are: $\psi_1:\sqrt[p]{2}\mapsto \sqrt[p]{2},\psi_2:\sqrt[p]{2}\mapsto \sqrt[p]{2}\xi,\ldots, \psi_{p}:\sqrt[p]{2}\mapsto \sqrt[p]{2}\xi^{p-1}$  Now, I need find the extension of $\mathbb{Q}(\sqrt[p]{2})(\xi)\to \mathbb{Q}(\sqrt[p]{2},\xi)$. In this case, because $x^{p-1}+x^{p-2}+\cdots +x+1=\min_{\mathbb{Q}(\sqrt[p]{2})}(\xi)$, i have that $x^{p-1}+x^{p-2}+\cdots+x+1=0$ implies $x\in \left\{\xi,\xi^2,\ldots, \xi^{p-1}\right\}$ (therefore, exists $p-1$ extensions) The extensions are: $\bar{\psi}_{1}:\xi\mapsto \xi,\ldots, \bar{\psi}_{p-1}:\xi\mapsto \xi^{p-1}$  By 6) and 7), there are $p(p-1)$ $\mathbb{Q}$-automorphism of $\mathbb{Q}(\sqrt[p]{2},\xi)$. This are:   $\psi_{i,j}:\sqrt[p]{2}\mapsto \sqrt[p]{2}\xi^{i},\, \xi\to \xi^{j}$ where $i=0,1,2,\ldots, p-1$ and $j=1,2,\ldots, p-1.$ I would need to prove that $\min_{\mathbb{Q}(\sqrt[p]{2})}(e^{{2\pi i}/p})=x^{p-1}+x^{p-2}+\cdots +x+1$  and  explicitly find the group of automorphisms (that is, see some group isomorphic to the group of automorphisms found in part 8) How can I find the group? actualization 1. Is $x^{p-1}+x^{p-2}+\cdots+ x+1$ irreducible over irrationals (or in real numbers)? (and, by consecuence, irreducibl over $\mathbb{Q}[\sqrt[p]{2})$


I am mounting a PCB, which deals with currents up to 5A and essentially switches down 60V to 12V and 5V, on a bicycle frame. I have four holes, one at each corner, that are padded with copper traces to the ground plane. Is it ok to fix the pcb to the frame by screwing the pcb through these holes directly on the metal of the frame or can this lead to problems? Thank you for your help!

I want to implement a control system I designed for a light electric motorbike. I would like to mount it as professionally as possible on the chassis. It consists of a power system pcb and a SAMC21 development board which I'll merge later once this all works properly. I have tried screwing it directly on the aluminium chassis but have found that shocks and vibrations from the horn disturbed the system or even destroyed it upon large shocks like a few hammer hits. Is there a specific way car and motorcycle manufacturers mount their electronics to make their system as robust as possible? Thank you for your help!


If $f:[a,b] \to \mathbb{R}$ is continuous and increasing, then the inverse $f^{-1}$ exists and   $$\int_a^b f(x)dx + \int_{f(a)}^{f(b)} f^{-1}(x)dx = f(b)b - f(a)a.$$  This is obvious by looking at a graph where the integrals are areas of regions that cover a rectangle of area $f(b)b$ with a rectangle of area $f(a)a$ removed.  I recall this is proved rigorously using integration by parts but I can't reconstruct the proof.  Can anyone please help?

Suppose $f$ is a continuous, strictly increasing function defined on a closed interval $[a,b]$ such that $f^{-1}$ is the inverse function of $f$. Prove that,   $$\int_{a}^bf(x)dx+\int_{f(a)}^{f(b)}f^{-1}(x)dx=bf(b)-af(a)$$   A high school student or a Calculus first year student will simply, possibly, apply change of variable technique, then integration by parts and he/she will arrive at the answer without giving much thought into the process. A smarter student would probably compare the integrals with areas and conclude that the equality is immediate.  However, I am an undergrad student of Analysis and I would want to solve the problem "carefully". That is, I wouldn't want to forget my definitions, and the conditions of each technique. For example, while applying change of variables technique, I cannot apply it blindly; I must be prudent enough to realize that the criterion to apply it includes continuous differentiability of a function. Simply with $f$ continuous, I cannot apply change of variables technique.  Is there any method to solve this problem rigorously? One may apply the techniques of integration (by parts, change of variables, etc.) only after proper justification.  The reason I am not adding any work of mine is simply that I could not proceed even one line since I am not given $f$ is differentiable. However, this seems to hold for non-differentiable functions also.  I would really want some help. Pictorial proofs and/or area arguments are invalid.


Hi! Can anyone help me out with this question I found on my practice paper?   For part a) I think it is a ARMA (1,1) process? is that correct? and how do I calculate the mean of the ARMA model? is it the same as AR model? If it is then E(yt) - 5/ (1-0.30) = 7.14?   For part b) I identified as the AR(4). Is that correct?

Can anyone help me out with this question I found on my practice paper?  The series $\{y_t\}$ is described by $$ y_t = 5+0.3y_{t-1}+\epsilon_t+0.9\epsilon_{t-1}. $$ Identify the specific ARIMA model. What is the mean of the series $\{y_t\}$?  I think it is a ARMA (1,1) process? is that correct? And how do I calculate the mean of the ARMA model? Is it the same as AR model? If it is then $$ E(y_t) = 5/ (1-0.30) = 7.14?$$    The sample ACF and PACF plot of a series are given above. Appraise the patterns and judge which ARIMA model fit the series. Justify your conclusion.  I identified as the AR(4). Is that correct? Since ACF has an exponential decay and PACF has a cut off? Differencing is not needed as the ACF decreases sufficiently to 0.


I am doing a project on exchange rates where I try to model the relation between exchange rates using PCA. Later, I want to relate these principal components to macroeconomic factors. I find that the first principal component produces all positive loadings/weights. I believe this has to be due to the fact that all currencies are expressed relative to the Euro, so all currencies behave in the same way relative to the Euro. Is my reasoning correct? Kind regards.

I performed principal component analysis (PCA) with R using two different functions (prcomp and princomp) and observed that the PCA scores differed in sign. How can it be?  Consider this:  set.seed(999) prcomp(data.frame(1:10,rnorm(10)))$x              PC1        PC2  [1,] -4.508620 -0.2567655  [2,] -3.373772 -1.1369417  [3,] -2.679669  1.0903445  [4,] -1.615837  0.7108631  [5,] -0.548879  0.3093389  [6,]  0.481756  0.1639112  [7,]  1.656178 -0.9952875  [8,]  2.560345 -0.2490548  [9,]  3.508442  0.1874520 [10,]  4.520055  0.1761397  set.seed(999) princomp(data.frame(1:10,rnorm(10)))$scores          Comp.1     Comp.2  [1,]  4.508620  0.2567655  [2,]  3.373772  1.1369417  [3,]  2.679669 -1.0903445  [4,]  1.615837 -0.7108631  [5,]  0.548879 -0.3093389  [6,] -0.481756 -0.1639112  [7,] -1.656178  0.9952875  [8,] -2.560345  0.2490548  [9,] -3.508442 -0.1874520 [10,] -4.520055 -0.1761397   Why do the signs (+/-) differ for the two analyses? If I was then using principal components PC1 and PC2 as predictors in a regression, i.e. lm(y ~ PC1 + PC2), this would completely change my understanding of the effect of the two variables on y depending on which method I used! How could I then say that PC1 has e.g. a positive effect on y and PC2 has e.g. a negative effect on y?    In addition: If the sign of PCA components is meaningless, is this true for factor analysis (FA) as well? Is it acceptable to flip (reverse) the sign of individual PCA/FA component scores (or of loadings, as a column of loading matrix)?


So I have an iPhone 4 that's been happily jailbroken on iOS 6.1.2 for a while now, but I want to upgrade to 7.0.6. I downloaded the IPSW for it and shift-clicked on update, but I get the error 'The iPhone could not be restored. An unknown error occurred (3194)'. I read up on it and proceeded to correct my hosts and firewalls, but nothing seems to work.  So, the question is: Is what I'm trying to do even possible, or should I just settle for iOS 7.1 with no jailbreak? Also, is there any way to update without using iTunes, because it seems to be the only thing causing the problem?

I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this?


function getx(x) {   const id = 'x';   console.log(id); }   function displayx() {    console.log(id); } <div class="form-check">   <input class="form-check-input" type="radio" name="flexRadioDefault" id="flexRadioDefault1" onclick="getx(1)">   <label class="form-check-label" for="flexRadioDefault1">     Default radio   </label> </div>   <button type="button" class="btn btn-primary m-3" id="button" data-bs-toggle="modal" data-bs-target="#modal" onclick="displayx()">         Button1 </button>    When clicked on radio button,function getx() executes properly, but after clicking on radio button, when clicked on normal button (id="button") getting error in function displax() Error is Uncaught ReferenceError: id is not defined I tried var also instead of const but still function displayx() is not getting value of "id". Thanks in advannce.

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


In trying to force the author name to be in capital letters in citation while keeping normal letters in the reference list. In this  there is an answer that suggests small changes in the file apalike.bst as a way to achieve this goal. Well, for my surprise, when I searching for the mentioned file through the folders of my linux distribuition, I got two matches instead of one. The two files apalike.bst are in the following paths:  ./local/texlive/2016/texmf-dist/bibtex/bst/base/apalike.bst ./share/texlive/texmf-dist/bibtex/bst/base/apalike.bst  From the exposed, my questions is:  What is the purpose to be two copies of this file?  Which one should I copy and change to achive what I want?  There is a better solution to work around this issue with natbib?

Debian and Ubuntu have very good texlive packaging. But I'd like to use tlmgr to have a more fine-grained control about upgrades and which packages I want to be installed.   So how do I install "vanilla" TeXLive on Debian/Ubuntu?   Also how do I make dpkg aware that I have TeXLive installed?


I am still new in latex...I have tried many times to write this equation in latex, but no way...always error...any help, please.   My Regards.

how we write this equation in latex in given form


Does the series $\sum_{n=1 }^{\infty}1/p_{j} $ of  reciprocal primes converge?  Experimentally, it seems convergent.

Is this series known to converge, and if so, what does it converge to (if known)?  Where $p_n$ is prime number $n$, and $p_1 = 2$,  $$\sum\limits_{n=1}^\infty \frac{1}{p_n}$$


I have to restart my Oracle database because of view changes in the SPFile. I tried to shutdown and startup, but I don't know how to startup in the right way again.

When trying to connect to an ORACLE user via TOAD (Quest Software) or any other means (Oracle Enterprise Manager) I get this error:     ORA-011033: ORACLE initialization or shutdown in progress


I had used this in a question:  cellNum = [VLOOKUP("string", '2012'!A:M, 13, FALSE)]   The light grey syntax color started at the single quote but then continued until the end of the line. Should it not have stopped at the next single quote?  [EDIT] No highlighting here? In that case, you can view it here:

I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange?


Let's suppose there is a company "acme", that ships products world-wide. They have multiple sites, for example there is a site for Australia - acme.com.au  and a site for UK - acme.co.uk. Both sites have lots of identical content on pages (index, about, some product pages...)  Will be these sites penalized in results of Google Search and what can be done if so?  Thanks

Google clearly states that duplicate content within a single, or multiple, domains is not advised. This is understood, but I am not sure of any exceptions for sites with region-specific content that is often replicated across locales.  For example, a site's /en-us/about page could be identical to /en-uk/about, whereas most likely /en-ja/about is unique.  Are GYM smart enough to understand that the initial URL depth is a locale specifier? Is there any robots.txt or header, etc, trickery that I should include to outline the site's international structure?


Opening Stage of another Class is achievable on Button Click, how can I open stage of another based on TextField Input.  Example :     enterWordtxtfld.setOnAction(event ->{      eventDisplayCard edc = new eventDisplayCard();      if(enterWordtxtfld.getText() == "1") {     //class to open     edc.start(eventDisplayCard.classStage);      }     else if(enterWordtxtfld.getText() =="2") {          //class to open     edc.start(eventDisplayCard.classStage);       }     else if(enterWordtxtfld.getText() =="3") {     //class to open         edc.start(eventDisplayCard.classStage);     }       //clear field     enterWordtxtfld.clear();  });   I anticipate any suggestions

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


My question is simple. Green light is more similar to red light than violet, then why is violet reddish and green not? in the language of frequencies and wavelengths, red and violet should contrast each other. Then why do they don't?

When people are asked to match monchromatic violet light with an additive mix of basic colours, they (paradoxically) mix in red.  In fact, the CIE 1931 color space chromaticity diagram shows this effect begins at about 510nm (greenish-cyan), where people mix in no red.  From that point on, the higher the frequency of the light source, the more red they mix in.    This effect is reflected by the red curve of the , which has an additional bump in the area of blue light.  However, that curve does not match the actual spectral sensitivity of red cones.  So where does this additional perception of red at higher frequencies come from?


Theorem: Let X and Y bet non empty sets, then there exist a surjection from X to Y and a surjection from Y to X if and only if there exist a bijection betwen X and Y.  Do anyone have an idea how to prove this?

We have that the Axiom of Choice is equivalent to the principle that every surjection has a right inverse. However, without the Axiom of Choice we can determine for some $X$ that $X\succeq Y\implies Y\preceq X$. Some immediate instances are when $X$ is finite (by the Principle of Finite Choice) and even when $X$ is countable (put in bijection with $\mathbb{N}$ and then choose the least element of the preimages).  I was wondering for what other $X$ does this hold? Clearly it holds for well-orderable sets, but does the principle extend to sets like $\mathcal{P}(\mathbb{N})$ or any other set that ZF can 'sanely' construct (as in be created without Choice)?  That is my first question. My second question is whether the following principle is equivalent to the Axiom of Choice: $$X\succeq Y\wedge Y\succeq X\implies X\simeq Y$$ This principle somewhat mirrors Schroeder-Bernstein, and can be derived with the Axiom of Choice; however, I've never seen a proof (not even a remark) that it is equivalent to or weaker than Choice.  These questions are just out of personal curiosity.   Notation: $X\succeq Y$ means $X$ surjects onto $Y$, and $Y\preceq X$ means $Y$ injects into $X$.


This is actually a doubt I got while solving . The thing is I know how to convert $2\arctan(3/4)$ to $\arctan(24/7)$ by using the $\arctan x + \arctan y$ identity, but how do I do the opposite? Please help!

I'm having problem with showing that: $$\arctan(\frac{2}{3}) = \frac{1}{2} \arctan(\frac{12}{5})$$  I would need some help in the right direction


Show that $I-BA$ is invertible if $I-AB$ is invertible. And also, we have to prove that eigenvalues are same for $AB$ and $BA$  Till now, I used the equation $(I-AB)(I-AB)^{-1}=I$ which gives $(I-AB)AB(I-AB)^{-1}=AB$ but I don't know how to proceed further.  Any hint would be sufficient !

assume $A,B\in M_n(F)$ if  $I-AB$ be  invertible then  how  to prove $I-BA$ is invertible and how find inverse of $I-BA$   Thanks in advance


"Does creativity comes with insanity?"    OR     "Does creativity come with insanity?"  Which of the above sentence is grammatically correct and why? What effect does using the word “Does” causes on the verb usage in the sentence?

Can you please help me better explain the structure below to my student?  "Does beauty has standards?"  Isn't the rule that the second verb (have) goes in the infinitive form in questions with do/does?  She understands the agreement in the structure "Beauty has standards" and is trying to apply it in the question form.


Let $X$ a normed space. Let $S(0,1)=\{x\in X: ||x||=1\}$ Prove that $X$ is banach iff $S(0,1)$ is complete.  My attempt: $(\implies)$ Note $S(0,1)\subset X$ and we have $X$ is banach space.  Let $\{x_n\}$ a cauchy sequence in $S(0,1)$. We need prove that $\{x_n\}$ converge.  As $\{x_n\}$ is cauchy then exists $N$ such that if $n,m>N$ then $||x_n-x_m||<\epsilon$  Here i'm stuck.  $(<-)$  Let $\{x_n\}$ a cauchy sequence in $X$. Note for $n,m>N$ we have $||x_n-x_m||<\epsilon$.

Let $X$ be a normed vector space.   Show that if a subsequence of a Cauchy sequence converges, then the whole sequence converges. Use the part 1 to show that $S = \{x\in X : \|x\| = 1\}$ is complete if and only if $X$ is Banach.     I have found the first part in a book, but I do not how to prove part 2. Thanx regards


I need to write a query that resets the identity on all tables that have an identity column and are empty.

I have a table with an IDENTITY column. While developing I delete the rows from time to time and add them again. But the IDENTITY values always kept increasing and didn't start from 1 when I added them again. Now my id's go from 68 -> 92 and this crashes my code.  How do I reset the IDENTITY value?


The length metrics used in physics are usually a squared norm, like the following: $$ds^2 = g_{\mu \nu} \, dx^{\mu} \, dx^{\nu}. \tag{1}$$  What other kinds of continuous metrics could we define?  Why not the following multi-linear candidates? \begin{align} ds &= g_{\mu} \, dx^{\mu}, \tag{2} \\[1ex] ds^3 &= g_{\mu \nu \lambda} \, dx^{\mu} \, dx^{\nu} \, dx^{\lambda}, \tag{3} \\[1ex] \vdots \\[1ex] ds^n &= g_{\mu_1 \mu_2 \mu_3 \dots \mu_n} \, dx^{\mu_1} \, dx^{\mu_2} \, dx^{\mu_3} \dots dx^{\mu_n}. \tag{4} \end{align} What are the basic rules that "forces" physics to use the "squared" metric (1)?

What a metric should necessarily do is it should give me a way to associate a frame invariant number with a given pair of spacetime events. Now, if I use a higher rank tensor field (say, for example, a tensor field of rank 3: $g_{\mu \nu \rho}$) then also I can certainly produce a frame invariant scalar out of a given displacement $\vec{A}$ in this trivial way: $ I := g_{\mu \nu \rho} A^{\mu}A^{\nu}A^{\rho}$. Since the components of the higher rank tensor and that of the displacement vector are going to transform in a covariant and a contravariant manner respectively, the cooked up quantity is certainly a scalar.   Another crucial property, which I think has more direct physical content than the previous one, is that between two inertial frames, at least one such transformation should exist that leaves at least one metric invariant. i.e., There should exist at least one combination of transformation matrix $\displaystyle\frac{\partial{x^{\alpha}}}{\partial{x^{\mu '}}}$ and metric $g_{\alpha \beta \gamma}$ that satisfies the following equation:      $\displaystyle\frac{\partial{x^{\alpha}}}{\partial{x^{\mu '}}}\displaystyle\frac{\partial{x^{\beta}}}{\partial{x^{\nu '}}}\displaystyle\frac{\partial{x^{\gamma}}}{\partial{x^{\rho '}}} g_{\alpha \beta \gamma} - \delta_{\mu '}^{\alpha}\delta_{\nu '}^{\beta}\delta_{\rho '}^{\gamma} g_{\alpha \beta \gamma} =0$    The last thing I can think of that can put a restriction on the choice of a tensor as a metric is the existence of a possibility of finding a metric compatible symmetric connection field. Following the usual procedure of finding the expression for a metric compatible symmetric connection field, I reached following condition (unlike the case of the usual two rank metric where we get a full-fledged expression) for the connection in the terms of the metric:      $g_{\nu \rho k_1} \Gamma^{k_1}_{\mu \lambda} - g_{\lambda \mu k_2} \Gamma^{k_2}_{\rho \nu} = \displaystyle\frac{1}{2} (\partial_{\nu}g_{\rho \lambda \mu} + \partial_{\rho}g_{\lambda \mu \nu}  - \partial_{\lambda}g_{\mu \nu \rho}  - \partial_{\mu}g_{\nu \rho \lambda}) $   My question is that if it is possible to satisfy the two highlighted conditions then can we use such a 3 rank (or even higher rank tensors with similarly produced conditions) tensor fields as metric fields?   PS: This is NOT a proposal for a new home-production theory of gravity (or that of anything for that matter) but rather it is just that I am trying to understand why a two rank tensor is used in General Relativity as the metric. Thank you.


When do the apt packages get published to  and removed from  for a given Ubuntu release? As at 2020-06-11, this is the current state for recently end of life releases: Release       | End of life | archive.ubuntu.com | old-releases.ubuntu.com ============================================================================ 10.04 lucid   | 2015-04-30  | No                 | Yes 12.04 precise | 2017-04-28  | Yes                | Yes 14.04 trusty  | 2019-04*    | Yes                | No  End of life dates are from . Is there an established policy on when the apt packages get moved? *Trusty's end of Standard Support is 2019-04 but End Of Life is 2022-04 for paid Extended Security Maintenance.

The old-releases.ubuntu.com mirror hosts the repositories for EOL Ubuntu releases. The  currently lists up to 11.10 (or 12.04.3 if you count point upgrades), but the  lists up to 13.04. Why the discrepancy? When will the main page be updated? When will the newest EOL release (13.10) be shifted here?


I'm wondering what prepositions to use after "assist someone." It seems there is a choice between "in" and "with," but I don't know if they are freely interchangeable. If they are interchangeable in particular sentences, is there any subtle difference?   You will be employed to assist in/with the development of new equipment.     Two men are assisting the police in/with their enquiries.     We are looking for people who would be willing to assist in/with the group's work.     Another doctor assisted him in/with the operation.     A senior academic would assist him in/with his work.     The cream assists in/with the prevention of skin cancer.   Could it be that "in" followwed by a noun (phrase) suggests that work of a more general nature is involved, whereas "with" suggests more specificity, tied to a paritcular task?

He assisted in the editing of the movie. He assisted with the editing of the movie. He assisted at the editing of the movie.  Is "assist in" the same as "assist with"? Can I always substitute the one where the other is used, or is there a difference in meaning? (I think "assist at" refers to a place where a person is assisting, as in "He assisted at the place where the editing was taking place".) When I use Google to look for the definition, it gives me the following as the main definition:  help (someone), typically by doing a share of the work  And gives two example sentences:  "a senior academic would assist him in his work"  and, after a bullet point with the following extra explanation:   help by providing money or information.  "they were assisting police with their inquiries"  So is the distinction between in and with really tied to the definitions above, or are these example sentences just a coincidence?


I have many polygons which represent different areas (with different plant species in each of them).  I want to “link” some information to the polygons in order to later be able of seeing which kind of vegetation is in each of the areas (or polygons).  I attach an image so that you can see better what I am trying to explain and do.    The attribute tables of all the polygons are like shown in the picture, and I would like to add the information there is in the excel table.   In each polygon I want to have the information corresponding to the row belonging to the area (as you can see each area has a number and correspond to a specific polygon).   Then, in each polygon should have the same amount of species (all of them) and the information which will be specifically belonging to the area (or polygon) which is based on the numbers (1, 2, 3 or 0) which correspond to the abundance of each of the species in each area.  After, I will need to select the different areas or polygons by if they have 3 of Acer campestre, or 1 of Calluna vulgaris…. For example when selecting by attributes to select: 2 of abundance of Acer campestre species and then all the polygons with this characteristics to be in another colour.

I have a map with different polygons (118). Each of this polygons represent diferent vegetation types.  For each of those polygons I have data of which species there is and how abundant they are (the abundance is measured with a scale from 1 to 3).  I would like to "link" (I am sorry if its not the correct way of name it) the data of which species and abundance there is in each of those polygons.   I would like afterwards to be able of selecting the different polygons containing the same abundance and species.  In the polygons I created there is no atributes associated other than (FID, shape and Id. the 3 of them created alone by the program when I drew them) and the tables I have in excel with the data I want to "link" to the polygons contain a column called species and another abundance.  As you can see, I'm pretty new using the program...    As I have tried to do what you all suggest in the comments down here, and I couldn't achieve what I was wanting to do (provably because of my bad explanation before...)  I leave a picture:  As you can see in the attribute table, that is how every attribute table of each polygon (which represents one area) looks like. On the right there is how I have my data in excel. Could you please suggest something I could do in order to add to the polygons attribute table the data belonging of species and its abundances (polygon number 1 has to have all the species (Acer mons, Acer pseu, Acer repens….) and its abundance (which are the numbers of the row Area1).


Is any of these two sentences incorrect:  -(without that): "To ensure the voters are not influenced by mass-media, the campaign will end 7 days before the elections take place."  -(with that): "To ensure that the voters are not influenced by mass-media, the campaign will end 7 days before the elections take place."  Is the presence of that mandatory?

He will understand that I was not joking.   He will understand I was not joking.  Which of the sentences is correct? Are there any specific rules about the use of "that" in the sentences I reported as example?


Kit includes only 2 cords SFF-8087 to 4xSATA... Sum is 8. I need 16. What should I do? No way to change the controller. But can buy additional cards or wires if needed. Please advise.

I've doing some researches since few days and I haven't really got an answer to my question.  I am in the process of building a huge file server for the company I work for. We bought a server case  with 24 bays and drives. Now I am stuck at the point where I have to choose the RAID card. I saw a RAID card from LSI that offer 6 internals mini-SAS 8087 ports (6x4) and would work perfectly with my build. However, it's not cheap.  I have been reading about the subject and I found something called SAS Expander. They are cheap.  with 6 mini SAS 8087 for 225$ (instead of 1150$ of the other one).  Now my question, how would I link an SAS Expander with a RAID card ? Do I need to a buy a RAID card with only 1 external 8088 port and link it with the other card ? Could someone clarify this for me because I haven't found any good documentation on it.  Thanks you.


If I want to write a check from one of my accounts, I can obviously order a checkbook. The thing is, I don't want or need a whole checkbook. I might just need, like, 1 check. Maybe 2.  Now, banks nowadays allow depositing checks from just scanning them via a mobile app. So, really, most/all security features of the check (e.g. magnetic ink) are kind of irrelevant nowadays.  Assuming both parties involved in the transaction are fine with this, how can I actually print my own check so that it looks like a check I ordered by mail? Are there templates out there somewhere?

Are there any laws prohibiting the use of home made checks, or must I always use a bank created check. Is there a legal directive I can reference?


In my select statement there is a CASE WHEN THEN ELSE END AS statement that I am not able to filter on in my WHERE clause. I do not see why this would be an issue, could someone shed some light?  SELECT         CASE      WHEN m.Country IN ('CANADA', 'UNITED STATES', 'USA', 'MEXICO') THEN 'NA'  WHEN m.Country IN ('BRAZIL') THEN 'JD2'      WHEN m.Country IN ('NZ', 'NEW ZEALAND', 'AUSTRALIA', 'AUSTRALASIA') THEN 'ANZ'  ELSE 'Unknown'      END AS DerivedRegion,     m.ID,     m.[Account Name],  m.[Display Name],  m.[Last Name],  m.[First Name] FROM dbo.Users AS m WHERE DerivedRegion = 'Unknown'   There WHERE clause gives me the error: Invalid column name 'DerivedRegion', why?

I have a query which is meant to show me any rows in table A which have not been updated recently enough. (Each row should be updated within 2 months after "month_no".):  SELECT A.identifier      , A.name      , TO_NUMBER(DECODE( A.month_no              , 1, 200803               , 2, 200804               , 3, 200805               , 4, 200806               , 5, 200807               , 6, 200808               , 7, 200809               , 8, 200810               , 9, 200811               , 10, 200812               , 11, 200701               , 12, 200702              , NULL)) as MONTH_NO      , TO_NUMBER(TO_CHAR(B.last_update_date, 'YYYYMM')) as UPD_DATE   FROM table_a A      , table_b B  WHERE A.identifier = B.identifier    AND MONTH_NO > UPD_DATE   The last line in the WHERE clause causes an "ORA-00904 Invalid Identifier" error. Needless to say, I don't want to repeat the entire DECODE function in my WHERE clause. Any thoughts? (Both fixes and workarounds accepted...)


How can I show that the ring $R=F[x,y,z]/(x^2-yz)$ is an integral domain? (Here $F$ is a field.)  I tried to prove this by contradiction. Suppose there are $\bar f, \bar g \in R-\{0\}$ such that $\bar f\bar g =0 $ in $R$, i.e. $fg$ is divisible by $x^2-yz$ in $F[x,y,z]$. But I don't know how to proceed.

Let $K$ be a field. Show that $x^2-yz$ is irreducible in $K[x,y,z]$. Deduce that $x^2-yz$ is prime.   If it is $K[x]$, then there are several methods which can be used to check whether a given polynomial is irreducible. But how do we check that when we have a polynomial of several variables? No idea how to do it. Any theorems? Moreover, in general, it is not true that irreducible elements are prime. So, how can I deduce the last result? Any help is appreciated.


I have a table which looks like the following:  EventProfileID    ParamName       ParamValue 1                 _CommandText    usp_storedproc_1 2                 _CommandText    usp_storedproc_2 2                 _CommandText    usp_storedproc_3 2                 _CommandText    usp_storedproc_100 3                 _CommandText    usp_storedproc_11 3                 _CommandText    usp_storedproc_123   What I would like my output to be is the following:  EventProfileID    ParamValue 1                 usp_storedproc_1 2                 usp_storedproc_2, usp_storedproc_3, usp_storedproc_100 3                 usp_storedproc_11, usp_storedproc_123   However I am having some bother.  If I do a select on one of the event profile ID's I can get an output using the following logic:  SELECT LEFT(c.ParamValue, LEN(c.ParamValue) - 1) FROM ( SELECT a.ParamValue + ', ' FROM DP_EventProfileParams AS a WHERE a.ParamName = '_CommandText' and a.EventProfileId = '13311' FOR XML PATH ('') ) c (paramvalue)   However that just gives me the output for one EventProfileID and also I would like the EventProfileID as part of the output.  Can anyone give me any pointers in the right direction into how I can expand my code to include this and allow the code to be dynamic so that I can show all EventProfileID's?  Thanks

How do I get:  id       Name       Value 1          A          4 1          B          8 2          C          9   to  id          Column 1          A:4, B:8 2          C:9


All the things mentioned above are working fine in Firefox but I'm having problem in Google Chrome. I'm posting below the screenshots of both the browsers displaying the same pages differently.  Firefox :  As I said, everything is normal in Firefox.    Google Chrome :  All the images are being displayed in a weird way. When I click on an image, it redirects me to the page hosting the image , instead of zooming it. Also this error is displaying in the console.   All other sites are working just fine on Chrome. Google homepage, images and search results are the places I've encountered problems on.

All the things mentioned above are working fine in Firefox but I'm having problem in Google Chrome. I'm posting below the screenshots of both the browsers displaying the same pages differently.   Firefox :  As I said, everything is normal in Firefox.   Google Chrome :  All the images are being displayed in a weird way. When I click on an image it redirects me to the page hosting the image, instead of zooming it. Also this error is displaying in the console.     All other sites are working just fine on Chrome. Google homepage, images and search results are the places I've encountered problems on.


I have this:  RUN curl -sL https://deb.nodesource.com/setup_11.x | sudo -E bash - RUN apt-get install -y nodejs=11   but I get:     E: Version '11' for 'nodejs' was not found   I also tried:  RUN apt-get install -y nodejs=11*   does anyone know how I can find out which versions are available? The problem is that node version 12 is already installed on this machine and I want to downgrade the Node.js version here.

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


I currently have a php script to send emails from Ubuntu server with sendmail.   $to = $sendTo; $subject = $subjectPrefix . $subject; $txt = $message; $headers = array(   "From: ". $email,   "Reply-To: ".$email,   "Content-type:text/html;charset=UTF-8",   "MIME-Version: 1.0",   "X-Mailer: PHP/" . PHP_VERSION ); $headers = implode("\r\n", $headers);  if(mail($to,$subject,$txt,$headers)){   echo "sent"; } else {   echo "failed"; }   The emails send fine but always go into spam and have the server address attached to the email, for exmaple: "input@email.com"@ip-###-##-##-###.eu-west-2.compute.internal  How would i go about setting this to only show the input email and not go into spam?

This is a tricky one and I've always relied on techniques, such as permission-based emails (i.e. only sending to people you have permission to send to) and not using blatantly spamish terminology.  Of late, some of the emails I send out programmatically have started being shuffled into people's spam folder automatically and I'm wondering what I can do about it.  This is despite the fact that these particular emails are not ones that humans would mark as spam, specifically, they are emails that contain license keys that people have paid good money for, so I don't think they're going to consider them spam  I figure this is a big topic in which I am essentially an ignorant simpleton.


I know if $E/F$ is a finitely generated algebraic extension of fields, then $E/F$ is separable iff the Kahler differential $\Omega_{E/F}=0$. Question: I wonder if we only assume that $E/F$ is algebraic without finitely generated, and  $\Omega_{E/F}=0$, then is $E/F$ separable? Edit:  doesn't solve my question, since the answer there uses the assumption that $E/F$ is finitely generated.

I am in the middle of a proof where the author asserts that for a field extension $K/E$, $\Omega_{K/E} = 0$ implies that $K/E$ is a finite extension. I am aware of results in the other direction with additional strong hypotheses (finite simple algebraic extension that is also separable). The hypotheses we do have are as follows:  Let $K/k$ be an extension of fields with finite transcendence degree $n$. Suppose $f_1, \dots, f_n$ are elements of $K$ such that $df_1, \dots, df_n$ is a $K$-basis of $\Omega _{K/k}$. Let $E = k(f_1, \dots, f_n)$.   However, here if this were true, then it would moreover imply that it is a separable extension. Therefore, by the primitive element theorem, this would imply it is a finite, separable, algebraic, simple extension. This seems rather strong from just knowing that $\Omega_{K/E} = 0$.


I have created an Availability Group with one primary and one secondary read only replica. The configuration is as below:    Now I connect to the listener using SSMS with parameter APPLICATIONINTENT=READONLY; but all read and write requests are sent to primary server as is shown in Profiler:    Is there any configuration mistake of me?

We have an Always On "cluster" that consists of 2 servers (there will be more), so one is PRIMARY and other(s) is(are) SECONDARY. The idea was to dedicate SECONDARY as a readonly replica, so it would be a somewhat search-server.  I do know how to set ConnectionString in the C# so it will use SECONDARY replica - just add ApplicationIntent=ReadOnly.  But I don't understand how to address the SECONDARY from stored procedure if I'm using distributed query. Is there a way to set some parameters to the query (like WITH statements or something), so query would use only replica and not the PRIMARY node?  The thing is, obviously from the start server1 is PRIMARY and server2 is SECONDARY, but when server1 fails then server2 is PRIMARY and server1 will be SECONDARY after it get fixed. So I cannot just use the static server2's name.  So far I've managed to get current replica's server name as a variable and use it in EXEC:  -- find first available replica DECLARE @replicaServer nvarchar(50)  SELECT TOP 1     @replicaServer = RCS.replica_server_name FROM     sys.availability_groups_cluster AS AGC     INNER JOIN sys.dm_hadr_availability_replica_cluster_states AS RCS           ON RCS.group_id = AGC.group_id     INNER JOIN sys.dm_hadr_availability_replica_states AS ARS           ON ARS.replica_id = RCS.replica_id     INNER JOIN sys.availability_group_listeners AS AGL           ON AGL.group_id = ARS.group_id WHERE ARS.role_desc = 'SECONDARY'       AND connected_state = 1  -- and query it DECLARE @cmd nvarchar(MAX) = 'SELECT * FROM [' + @replicaServer + '].[somebase].[someschema].[sometable]' EXEC (@cmd)   But that's a shame, I guess.


I need to read from a number of files but sometimes they are not available or cannot be read from current user. This is the code I'm using to check if file is valid but I think I'm not using the using statement correctly.  private static bool fileAccessible(string filePath) {     using (FileStream fs = new FileStream(filePath, FileMode.Open)) {         if (fs.CanRead) {             return true;         }         else {             return false;         }     }      return false; // compiler says "unreachable code" }   Should I insert a try/catch block outside the using statement to catch errors raised by unavailable file or will using go on without raising an error if filePath is not available?  Bonus question: is this the correct way to check if file is available and accessible? If the answer is Yes can I change FileMode.Open to FileMode.Append to perform the same check on writable files?

Basically, I would like to check if I have rights to open the file before I actually try to open it; I do not want to use a try/catch for this check unless I have to. Is there a file access property I can check before hand?


I am a beginner in using Wilcoxon test to get the p-value. After applying the test to my data, I got the p-value < 2.2e-16. Does that mean that the samples I have are significantly different from each other? I am suspicious of such a result. I have looked at other related questions (such as  but I didn't really understand what this value means.   Can someone please explain?

For some tests in R, there is a lower limit on the  calculations of $2.22 \cdot 10^{-16}$. I'm not sure why it's this number, if there is a good reason for it or if it's just arbitrary. A lot of other stats packages just go to 0.0001, so this is a much higher level of precision. But I haven't seen too many papers reporting $p < 2.22\cdot 10^{-16}$ or $p = 2.22\cdot 10^{-16}$.   Is it a common/best practice to report this computed value or is it more typical to report something else (like p < 0.000000000000001)?


If angle α is reflex, and cos α = -9/41, without using a calculator, evaluate  (a) sin α (b) tan α (c) cos (α - 180 (degrees) .  I asked this question before but was unsure how to ask it again or renew it without creating another thread.  I really don't understand the process of working this out.  Would I bet right in saying: Cos a = -9/41. -9/41 = -0.225. cos-(cos inverse) -0.225 = 103.0028781629139. So Cos A = 103.0028781629139? (But what am I even trying to say in that instance. lol).

If angle $\alpha$ is reflex, and $\cos \alpha = -\frac{9}{41}$, without using a calculator, evaluate  (a) $\sin \alpha$ (b) $\tan \alpha$ (c) $\cos (\alpha - 180\deg)$     .


i've installed mac version from kyngchaos including all required packages ... ... and just noticed the following:  while windows version behaves like expected when trying to render an ordinary tif via "singleband pseudocolor" (see the image)   the same procedure on the current mac-release returns:   interesting detail: pressing "apply" in mac version doesnt change anything and if you press "OK" and re-open layer properties the "render type"-setting has  swiched back to "singleband grey".  even more interesting: "singleband grey" is faulty too: none of the options "color gradient", "min", "max", "contrast enhancement" does affect the way the tif is displayed,  neither do the "load min/max values" settings !  anyone any ideas?

In a raster layer's Style Properties, I can choose pseudocolor render type, and choose a color ramp and classify the raster.      However, when I click the 'Apply' button, or click 'OK', the visualization of the raster never changes.  I was able to output a 'colorized' version of the same raster using GRASS plugin.  I also reinstalled QGIS 2.8, and was able to adjust and see a raster stylings using the steps I outlined above.  So, can anyone confirm this as an issue, or confirm that there's a mistake somewhere in my process?  I should note that I'm on a Mac, 10.10.4, and I'm using the QGIS provided by , 2.10.1-1 .  Update 1: Here's a screenshot of the rest of my settings.      I have Grayscale set to off in the Style setting.  Also, I don't believe grayscale/color-blind Preview is available on the Mac version of QGIS.  They're does't appear to be the option where it , in the Menu Bar under View / Preview / Photocopy (grayscale) etc.  Either way-- I added a shapefile to show color.  Update 2: I've experimented with setting color interpolation to discrete, linear, and exact, but still am not able stylize using Singleband pseudocolor.  I've also confirmed that the 'Render' box on the the main map view is checked.  Also, I am able to adjust Color Rendering settings, like Hue, Blending Mode, etc., and see the results when clicking 'Apply' or 'OK'.  Update 3: As other Mac users are confirming this, I think it may be a bug. I've created a bug report at the official .


In the beginning of The Dark Knight Rises, Bane and his minions take over the airplane in which Dr. Pavel is transported. After having the control over the airplane, and having it wired up with cables, they bring in a body bag in which a seemingly dead person lies in. Then, they start a blood transfer with Dr. Pavel. But why? I guess they want, when the bodies are found, the body-bag-person will be identified as Pavel. I am sure that this little blood would not be enough, it only took some seconds. Is there any other reason or explanation?

In The Dark Knight Rises, at the beginning of the film Bane kidnapped a guy from the plane, then he drew blood from the guy he kidnapped. And then throughout the movie I didn't see any news regarding this kidnap scene. But, before the end of the movie we find out that the guy kidnapped by Bane was Dr Pavel. Bane needed him to convert the fusion project into a nuclear bomb and Dr Pavel was the only guy who could have done it.   But I don't understand, why did he draw blood from Dr Pavel?


when divide in c# Answer is different and when i divide from calculator answer is different kindly solve it.  c#  double div=(double)100000/30/9;  Answer 370.37037037037038  370.37037037037038*9*30 //100000.0000000000026    in calculator   Answer 370.3703703703704  370.3703703703704*9*30 //100000  i need exact answer like a calculator.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Is it possible to statically initialise part of a struct?  The stuct I have:     struct data {     char name[20];     float a;     int b;     char c; };   When initialsing and printing:  struct data badge = {"badge",307}; printf("%s,%d\n", badge.name, badge.b);   This will print out "badge", but not '307'.  How can I get this to use char name[20] and int b whilst ignoring float a.

I want to initialize a struct element, split in declaration and initialization. This is what I have:  typedef struct MY_TYPE {   bool flag;   short int value;   double stuff; } MY_TYPE;  void function(void) {   MY_TYPE a;   ...   a = { true, 15, 0.123 } }   Is this the way to declare and initialize a local variable of MY_TYPE in accordance with C programming language standards (C89, C90, C99, C11, etc.)? Or is there anything better or at least working?  Update I ended up having a static initialization element where I set every subelement according to my needs.


I am trying to set default value in dropdown when HTML page is loaded. I have filled the dropdown values dynamically from code as 0 = Select, 1 = Required and 2 = Not Required  I have written below line of code to set the value as "Required".  $("#ddltest option:contains('Required')").attr('selected', 'selected');   However the "Not Required" option is getting set.  C# fiddler link below:

I have a select control, and in a javascript variable I have a text string.  Using jQuery I want to set the selected element of the select control to be the item with the text description I have (as opposed to the value, which I don't have).  I know setting it by value is pretty trivial. e.g.  $("#my-select").val(myVal);   But I'm a bit stumped on doing it via the text description. I guess there must be a way of getting the value out from the text description, but my brain is too Friday afternoon-ed to be able to work it out.


I'm having difficulty in understanding . How can a proton which has slightly less mass than neutron transform into a neutron, positron and neutrino?   Form where does the extra mass for neutron,electron and neutrino come?  Is it that during the decay some of the binding energy gets converted into mass?

The mass of a neutron is greater than mass of a proton so how is it possible in positron emission for a proton to form a neutron and a positron?


All the sudden my site (drupal 7) shows rare characters like �0�1�0�  Also, the links doesn't work. All links in the site reload the home page.  I can't access example.com/user neither.  Please help. The site was working fine yesterday and did not make any change.  The encoding of the page is: UTF-8  Meta Content-Type is text/html; charset=utf-8  I can use Drush in the site. I already run drush cc all and drush cron and drush updatedb. But problem is not fixed.  Please help.

I just updated all my sites using the patch method of resolving the Drupal SA-CORE-2014-005 exploit. I just read reports that just yesterday there is someone from a Russian IP infiltrating drupal sites.     My main concerns are now:   How do I tell if my sites have been comprised? What should I search for in my apache access logs to detect if my site was a victim or not? So far what are these hackers doing to comprised sites?


This question is a variant of the pythagorean relation except that 2 was replaced by $e=2.71828...$

We now that Fermat's last theorem is true so there are not positive integer solutions to $$x^n+y^n=z^n$$ for $n\in\mathbb{N}$ and $n>2$.  But what about if $n\in\mathbb{R}$ or $n\in\mathbb{R}^+$?


I am using the following code, but it doesn't work.  drupal_block.module  function custom_blocks_theme($existing, $type, $theme, $path) {   return [     'custom_blocks__front_apps' => [       'variables' => [         'app' => NULL       ],     ],   ]; }   BlockTest.php    /**    * {@inheritdoc}    */   public function build() {     return [       '#theme' => 'custom_blocks__front_apps',       '#app' => 'test value',     ];   }   custom_blocks__front_apps.html.twig
Hello: {{ app }}
   My block is empty.        What is wrong with the code?

I'm trying to create a block that will pass a variable to its template. For now just some text but it will be an array later.  The default block variables such as label are working but I'm unable to get the value to show up in template.  Any ideas ?  FrontAppsBlock.php  namespace Drupal\custom_blocks\Plugin\Block;  use Drupal\Core\Block\BlockBase; use Drupal\Core\Block\BlockPluginInterface; /**  * @Block(  *   id = "front_apps_block",  *   admin_label = @Translation("Front Apps Block"),  * )  */ class FrontAppsBlock extends BlockBase implements BlockPluginInterface {    public function build() {     return array(       '#theme' => 'front_apps_block',       '#app' => 'test value',     );   }  }   custom_blocks.module  function custom_blocks_theme($existing, $type, $theme, $path) {   return [     'front_apps_block' => [       'variables' => [         'app' => null       ]     ]   ]; }   block--front-apps-block.html.twig
test: {{ app }}

label: {{ label }}


I want to download my data from QGIS to an existing table in Postgresql. I tried to use DB Manager, but the field add to existing table doesn't work. Maybe somebody knows what the problem is?  Or is there another way to solve the problem?

I want to append some data to a layer in my PostGIS DB using a shapefile, but when I use the Import layer/file tool in QGIS, it doesn't allow me to choose the append option.  Why is this and how do I get it to allow me to append?


I have read that running Ubuntu apps as root is dangerous. Why? Is it still dangerous on a personal non-networked computer? In particular, why shouldn't I run the file manager as root administrator?

I've often come across posts on forums or other websites where you see people joking in such a manner about running/logging in as root as if it's something awful and everyone ought to know about it. However, there isn't much that a search reveals on the matter.   It may be widely known to Linux experts, but I really don't know why. I remember always running as root when I first tried Linux years ago (Redhat and Mandrake) and don't remember running into any problems because of that.   There are actually some distros that have a bright red background with alert signs all over it as wallpaper for the root user (SuSe?). I still use the "Administrator" account for regular use on my Windows installation and haven't ever run into any problems there either.


Let $$f_{X,Y}(x,y) = 8xy\mathbb{1}_D(x,y)$$ with $D=\{0<x<y<1\}$  I want to find $F_{X,Y}(x,y)$, I do this by integrating:   $$ F_{X,Y}(x,y) = \int_{-\infty}^x \int_{-\infty}^y 8 x y dxdy$$ However now I think I misunderstand because I set up the integral on $D$ in this way:  $$ F_{X,Y}(x,y) = \int_{x}^1 \int_{0}^y 8xydxdy$$  This is because x is between 0 and y and y is between x and 1, however I get the wrong result. Is there a mistake in the boundaries of the integral?

Ley X,Y two random variables with density $f(x,y)=8xy \  \text{if} \   0<x<y<1$  Find the joint distribution F(x,y).  I find that $F(x,y)=2x^2y^2-x^4\ \text{  if}  \ 0<x<y<1$ but I dont know how to find the didtribution in other points.


How do I install Google Chrome on my Ubuntu 13.10 easily? I had downloaded the file called google-chrome-stable_current_i386.deb from google downloads but it doesnot install using Ubuntu Software Center.

How do I install a .deb file via the command line?


The question itself is self explanatory. As another query I would like to know if it's possible to replace the 'Y' option with 'Enter' keystroke.

I am new to Ubuntu and some little thing start to bug me. Such as when trying to install a program, Ubuntu asks,     Do you want to continue[Y/n]?   What is bugging me is why the letter "Y" is upper case and "n" is lower case. Do they have any significant reason why one is upper and the latter is lower? Whatever case I enter it doesn't change the outcome: it either continues or not. Are they trying to notify us that we can enter both and it won't change anything?


I've come across how to write over a left or right facing arrow but not one that's double-ended. I tried this below (but with \ in front of both [ and ] but for some reason this won't typeset here) but it doesn't work so any help would be greatly appreciated!  \[ a \xleftrightarrow{\text{x}} b \]   Many thanks!

This is difficult for me to explain, but how do I put words over a symbol? For instance, I want to add words over an equal sign. Anyone know the command/syntax for that?  Also adding ^ doesn't cut it..., I want the text to appear ON TOP.


Here is the code  int *p = new int[10]; ... delete[] p;   How does the program know how many elements were there when delete[] was called?  Suppose we inserted the following code in between:  p++;   Will the program try to free one more element? Will it just stop at the 10th element?

Foo* set = new Foo[100]; // ... delete [] set;   You don't pass the array's boundaries to delete[]. But where is that information stored? Is it standardised?


I've got a VM with 16gb of memory and recently it's been using some of the swap space.  At first I thought this was because it was using all the memory but then I read some articles about the Cached Memory and how the Linux Kernel uses extra memory for caching.  Checked that and saw that I've got about 13gb being allocated to caching.  I haven't been able to find any answers though as to why swap is being used.  Shouldn't the kernel use memory that is being used as Memory Cache space before it starts using swap space?    Thanks for linking me to that other question, didn't find that for some reason before.

Using swap space instead of RAM can drastically slow down a PC.  So why, when I have more than enough RAM available, does my Linux system (Arch) use the swap?  Checkout my conky output below:    Also, could this be the cause of speed and system-responsiveness issues I'm having?  Output of free -m :  $ free -m              total       used       free     shared    buffers     cached Mem:          1257       1004        252          0         51        778 -/+ buffers/cache:        174       1082 Swap:          502        144        357