Prove the following statement: If $n, m\in\mathbb{Z} $ and $g=$gcd$(n, m) $ then is  $$\varphi(m, n) =\frac{ \varphi(m) \varphi(n) g} {\varphi(g)}. $$  Hint: Prove the statement with induction  above the number of common prime divisors.   How can I do the first step of induction?

The third formula on the  states that $$\varphi (mn) = \varphi (m) \varphi (n) \cdot \dfrac{d}{\varphi (d)} $$ where $d = \gcd(m,n)$.  How is this claim justified?  Would we have to use the Chinese Remainder Theorem, as they suggest for proving that $\varphi$ is multiplicative?


Let $\{a_n\}$ be a sequence an $L$ a real number such that $\lim_{n\to\infty} a_n = L$ Prove that $\{a_n\}$ is bounded   This reminds me of the bounded monotone convergence theorem (BMCT) but in reverse. So I was thinking of proving by somehow reversing the proof of the BMCT. Am I approaching this correct? And are there alternative ways of doing this that may be simpler?

I don't understand this one part in the proof for convergent sequences are bounded.  Proof: Let $s_n$ be a convergent sequence, and let $\lim s_n = s$. Then taking $\epsilon = 1$ we have: $n > N \implies |s_n - s| < 1$ From the triangle inequality we see that: $ n > N \implies|s_n| - |s| < 1 \iff |s_n| < |s| + 1$. Define $M= \max\{|s|+1, |s_1|, |s_2|, ..., |s_N|\}$. Then we have $|s_n| \leq M$ for all $n \in N$.  I do not understand the defining $M$ part. Why not just take $|s| + 1$ as the bound, since for $n > N \implies |s_n| < |s| + 1$?


I wanted to put in my presentation a word or phrase (either one will do) that describes a person that easily gives up but is easily fired up. Please help me.

A friend of mine said that he was a cynic. I had told him that he was giving up too easily. In this situation, the worst case outcome was rejection, which logically speaking, was equivalent to not trying in the first place.  I want to say, "No, you aren't cynical, you are X," or "No, you aren't a cynic, you are a(n) X."  The closest I can come up with is unmotivated or intimidated.  What word describes a person who gives up too easily?


What software or tutorials are there that allow Word writers to write with LaTeX writers without Word writers having to learn LaTeX

Techinical question of this academic question:   I have an issue with my Supervisor: he likes to write papers on MS Word and I like to write in LaTeX. We have had issues with editing and formating since it is dificult to do it while working on different platforms.  I have tried the following to try to convert from LaTeX source code to MS Word format:   LATEX2RTF Pandoc  (PDF output from LaTeX)   But none of them give the desired output that I want:   Which is a 2-column IEEE format paper.  Does anyone has any advise on how to convert from LaTeX to Word efficiently?


When running a website through Google PageSpeed Insights I get the following response:     Optimize images      Properly formatting and compressing images can save many bytes of   data.      Optimize the following images to reduce their size by XX.XKiB (X%   reduction).      Losslessly compressing    could save   XX.XKiB (XX% reduction).   What do the tool mean by "Losslessly compressing?" Sounds like I could reduce the filesize without sacrificing image quality; but how?

We have several pages with good Pageseed-values - even those with 100/100. Since a few days however, Pagespeed claims across all sites (technically different, different servers) that our images could be more optimized.  Does anyone know what exactly has been changed by the algorithm?  On the one with PS 100/100 (before), we use jpegoptim, so we really don't know how to optimize further. Images are uploaded by our application and then optimized.  Any insight would be appreciated. Is there a changelog for PS anywhere?


When you promote a product or service that a user hasn't experienced yet, would you use 'Guarantee to love' or 'Guaranteed to love'?

I was wondering if you could help me out with the phrase "Authenticity guarantee". Is it proper English to use this?   Would  "Authentic guarantee" or "Authenticity guaranteed" be more correct?


What is the difference between available memory and free memory. Is available memory and cached memory are same. If not, what's the difference. I have referred some answers and they says available memory is easy to convert to used memory than free memory. So system keeps free memory as low. But my doubt is that, in that case why i have to clear cache to make my application run.

Within the output of top, there are two fields, marked "buff/cache" and "avail Mem" in the memory and swap usage lines:    What do these two fields mean?  I've tried Googling them, but the results only bring up generic articles on top, and they don't explain what these fields signify.


Are there any alternate compiler implementations for the Tex language? I know that there are variants (Luatex for instance), but do they all share the same codebase with Tex/Pdftex? What about Xetex, is that a completely separated implementation in terms of code base? Does it target the exact same language, or are there differences in what they support?  Edits to clarify:   with "alternate implementation", I mean a program that shares little or no code with the standard pdftex. Something rewritten from scratch (possibly in another language). I mean something that I can use to compile a real-world document in. If I understand correctly, Latex is a macro system based on Tex, so an alternate compatible implementation of Tex should be able to run these macros with little or no changes. I don't know what you mean with "any Tex format". Do you mean output formats? The example I have in mind is multiple compilers for the same language (e.g., Cpython or Pypy). For instance, there are many C compilers around; the two main ones are GCC and Clang. You can literally take the same C program and compile it with either of them (with very few exceptions regarding nonstandard features). Clang is a relatively new implementation, that provided in some cases greater speed and better error messages.  is certainly relevant, but I don't find any mention to the similarities/differences between these engines. Are they all minor improvements to the same codebase, or five completely separate implementations? Can I take the same file (a simple Latex document, for instance) and compile it with either of them without changes?

In Appendix D of The TeXBook, p. 387, in a discussion about automatic column sizing, Knuth tantalizes us with this:     Some implementations of TeX display the output as you are running, so that you can choose column widths interactively until a suitable balance is obtained.   What are these other “implementations” of TeX? Are they moribund or do they still exist?


Omit.txt  001 006 008 0016   Filetogrepfrom.txt  001 006 007 008 0016 00546 008 0031 00 0021 0016   I want to do   cat filetogrepfrom.txt | grep -a 00 | grep -v {lines from omit.txt}

I want to find patterns that are listed in one file and find them in other file. The second file has those patterns separated by commas.  for e.g. first file F1 has genes  ENSG00000187546 ENSG00000113492   ENSG00000166971   and second file F2 has those genes along with some more columns(five columns) which I need   region     gene           chromosome  start       end   intronic   ENSG00000135870 1   173921301   173921301 intergenic  ENSG00000166971(dist=56181),ENSG00000103494(dist=37091) 16 53594504    53594504 ncRNA_intronic  ENSG00000215231 5   5039185 5039185 intronic    ENSG00000157890 15  66353740    66353740   So the gene ENSG00000166971 which is present in the second file does not show up in grep because it has another gene with it,separated by comma.  My code is:  grep -f "F1.txt" "F2.txt" >output.txt   I want those values even if one of them is present,and the associated data with it.Is there any way to do this?


The screenshot shortcuts save either to the desktop or to the clipboard, but not to both at once. Is it possible to copy to clipboard, and to save in desktop, the same screenshot preferred in a single shortcut? If a single shortcut is not available, the only way is to save to desktop and then copy the saved image to clipboard manually?

Within OS X 10.11.6, the  Cmd ⌘   Shift ⇧   4  key combination saves a screenshot to the desktop by default.  Is there a way to automatically copy the file to the clipboard (in addition to saving the file), so that the screenshot can be pasted into a document?  Maybe there is some clever why to tee and pipe the image to the clipboard?  The intent is to:    save screenshot to a file and  copy screenshot to the clipboard    with a single command.   Examples are always appreciated.


As mentioned  the new size for sidebar ads is 300x250 px.   Now that the Community Promotion ads are going live, when will the dynamic bounty ads change size to match the new standard?  e.g., for   These still are 220x250 px in size.

You've probably seen this sidebar ad on one or more -enabled Stack Exchange sites over the years:    The image is dynamically generated from a non-officially SE app that uses the Stack Exchange API to fetch the bounties from a given site.  As far as I understand, the rendered image automatically scales to the allotted ad space - when the sidebar ads were 220x250, it would render in the sidebar as a 220x250 image while still looking quite oversized in the  meta (as it does right here).  With the new 2016 campaign starting, can we test whether this awesome dynamic ad works with the new sidebar width?


I have a Drupal 8 site. And I have approximately 5 pages in a site.  For example if a user hits login from the contact-us page the user should not redirect anywhere, they should stay on same page. How can I accomplish this?

I would like to redirect users after they log in. Is it possible to use hook_user_login() to make the redirection? How do I add the parameter for the redirection?


Define $$S=\sum _{r=1}^n a_r$$  How to prove the following inequality: $$\prod _{r=1}^n (1+a_r)\leq \sum _{r=0}^n \frac{S^r}{r!}$$

[Sorry, but I couldn't come up with a better title...]  I'm trying to prove that $$\prod_{i=1}^n (1+a_i) \leq 1 + 2\sum_{i=1}^n a_i$$ if all $a_i$ are non-negative reals with $\sum_{i=1}^n a_i \leq 1$ and it seems I'm stuck.  (And, no, this is not homework!)


iTunes by default stores its settings, the iTunes Library.itl file, and the music library audio tracks, inside the \Users\username\Music\iTunes folder.  I don't want my Music folder polluted with program settings, especially because I'm synchronizing that folder on the cloud. Via the settings panel I can only change the path of the audio tracks, but the settings remain in the default position.  Is there a way to completely move the iTunes folder to another path?  PS: I've looked at the answers to , but the focus there is on moving the media library only, not the whole iTunes directory.

This may happen later with my iMac, but right now it is happening for my iTunes on PC.  The PC had 60GB of partition to install Windows 7, and right now it is down to about 2GB of free space.  All iTunes purchases, including Music and Movies, are downloaded to  C:\Users\mike\Music\iTunes\iTunes Media\Music  C:\Users\mike\Music\iTunes\iTunes Media\Movies   which will make the C: drive have less and less free space.  (and C: will be more healthy if it has at least a couple of GB of free space).  What is the safest, most proper way to migrate all the media to an external hard drive J: ?  On J:, the path might be:  J:\iTunes\iTunes Media\Music   or  J:\iTunes Media\Music   My guess is that we can change the folder in iTunes, but won't iTunes go to that folder or create it, and find nothing, and index everything wrong?  So, should an exact copy of C:\Users\mike\Music\iTunes\iTunes Media be made as J:\iTunes Media first (probably 30GB of files copying), and then start iTunes and change the preference for the folder to the J: one?  Is there a standard or official method to do this?


Stack Exchange users have the ability to flag a post to be closed because the post at hand has content that doesn't fit into the topic-range covered by the given Stack Exchange site.  The dialog that appears offers a very, very limited selection of other Stack Exchange sites which the person who's flagging the post has to choose from. I'm wondering why isn't there a better menu for this that offers more choices?  I have seen a lot of topics on Stack Overflow which are about general Linux stuff (installation, dual boot, etc.) and so on that definitely belong to unix.stackexchange.com but alas! I'm unable to find any way to point exactly where the post belongs to because of the limited (5-6) choice of Stack Exchange sites (most of which I might add are definitely not that popular).  Is this a reputation points limitation (I've just reached 2K on Stack Overflow) or is this really that useless as a feature?

On the religion and culture stackexchange sites, many, many users will initially ask a question in a place that's kind of off-topic there, but are fully on-board elsewhere.    Christianity.SE, for example, gets a lot of general philopsophical questions that would be better on Philosophy, historical questions that might be better on History.SE, and hermenutical questions that are better on BH.SE.  It is, however, unreasonable in my mind for a user with a question to be required to have domain expertise on which sub-site each has. Indeed, even amongst users with a high amount of knowledge, there can be disagreement.  Likewise, , but as just about every one of those is in beta, the user would have to be very saavy (or would have to find that post) in order to nail it every time.  That said, recommending that a question be moved is much harder than it needs to be.  I have seen business rule logic that says, for example,    migration paths only exist to graduated sites (ergo politics, money, history, and quantitative finance wouldn't qualify) migration paths seem to be limited to 5.   Anything not on a migration path requires a moderator (and not just a high rep user) to get involved.  So, what is the reasoning behind this?  Note, I'm not asking for a solution (although the obvious solution would be to allow migration paths to any established site, beta or not, i.e. a VTC as off topic b/c it belongs on another site should allow you to pick any other site) - I just want to understand the business purpose in restricting migration paths to a small, predefined number for everyone other than a mod.


i have to get the Inner text based on dom x- path, but in the x-path div value keeps changing. how do i do it in automation anywhere object cloning in Chrome browser.  The xpath I am using is:  /html/body/div[5]/div[1]/section[1]/div[2]/div[1]/div[1]/div[2]/div[1]/div[2]/div[1]/div[1]/div[1]/div[1]/div[1]/div[1]/div[1]/div[2]/div[1]/div[1]/div[1]/div[2]/div[2]/div[1]/div[1]/div[1]/table[1]/tbody[1]/tr[1]/td[5]/span[1]/span[1] /html/body/div[5]/div[1]/section[1]/div[2]/div[1]/div[1]/div[3]/div[1]/div[2]/div[1]/div[1]/div[1]/div[1]/div[1]/div[1]/div[1]/div[2]/div[1]/div[1]/div[1]/div[2]/div[2]/div[1]/div[1]/div[1]/table[1]/tbody[1]/tr[1]/td[5]/span[1]/span[1]

There is a type and search drodown which will appear after user type in the value. I need to click on the dropdown which contains the name of the drop down field.   The problem here is that there is no unique attribute present (No unique class, no unique name) & the id keeps on changing after every login so cannot take id also.


When I run queries from one of my tables I get an error  Msg 605, Level 21, State 3, Line 1 Attempt to fetch logical page (1:8687634) in database 7 failed. It belongs to allocation unit 72057594364821504 not to 72057594052476928.  I did some googling and I found  which suggested running DBCC CHECKDB. I ran the check but it reported 0 allocation errors and 0 consistency errors so I'm not sure where to go from here. From other sites I saw that the problem might be a corrupted index so I deleted the (only) index of that table and I still get the same error when running a query. I did DBCC CHECKTABLE and got  Incorrect PFS free space information for page (1:8687634) in object ID 270624007, index ID 0, partition ID 72057594508083200, alloc unit ID 72057594052476928 (type In-row data). Expected value  50_PCT_FULL, actual value   0_PCT_FULL.  It's not in emergency mode or anything, is there a way to repair/rebuild this table without going into single user mode? I ran dbcc page(7, 1, 8687634, 3) with a result of  Msg 0, Level 11, State 0, Line 0 A severe error occurred on the current command.  The results, if any, should be discarded.

I am getting the following SqlException on calling a stored procedure:     Attempt to fetch logical page (5:65424) in database 2 failed. It belongs to allocation unit 7349876362857938944 not to 4899918190390149120.      System.Data.SqlClient.SqlException occurred   Message="Attempt to fetch logical page (5:65424) in database 2 failed. It belongs to allocation unit 7349876362857938944 not to 4899918190390149120.        Source=".Net SqlClient Data Provider"   ErrorCode=-2146232060   Class=21   LineNumber=257   Number=605   Procedure="ispDisplayCount"   Server="10.10.1.1"   State=3   What does this exception mean? Is there any resolution to the above issue?  Although the database referenced in the error above indicates tempdb, similar errors referencing Message 605, may be fixed using the answers below.      Msg 605, Level 21, State 3, Line 1   Attempt to fetch logical page (1:8687634) in database 7 failed. It belongs to allocation unit 72057594364821504 not to 72057594052476928.


So I have this code.  \draw(A)-- (X)-- (D) pic["$\epsilon$"] {angle= A--X--D};   And it works perfectly. But I don't know how to display numbers. For example   \draw(A)-- (C)-- (D) pic["$34$"] {angle= A--C--D};   and I get this    How to fix that? I mean how can I display the number (with degree symbol) like I did epsilon?

Here is my code.  \resizebox{\textwidth}{!}{ \begin{tikzpicture} \selectcolormodel{gray} \begin{axis}[xlabel=Voltage,ylabel=Current,title=IV Characteristics of PV Module] \node[label={Set 1}] at (axis cs:2,60){}; \node[label=Set 2] at (axis cs:2,150){}; \node[label=Set 3] at (axis cs:2,240){}; \node[label=Set 4] at (axis cs:2,305){}; \addplot table [x=v1,y=i1, col sep=comma,mark=none] {SolarCellIV.csv}; \addplot table [x=v2,y=i2, col sep=comma,mark=none] {SolarCellIV.csv}; \addplot table [x=v3,y=i3, col sep=comma,mark=none] {SolarCellIV.csv}; \addplot table [x=v4,y=i4, col sep=comma,mark=none] {SolarCellIV.csv}; \node at (axis cs:12,360) {Set 1: 44.9 degreeCelsius}; \end{axis} \end{tikzpicture}}   I want the symbol for Degree Celsius in place of the text. How do I do so?


I am watching the following video lecture:    In there, he talks about calculating gradient of $ x^{T}Ax $ and he does that using the concept of exterior derivative. The proof goes as follows:   $ y = x^{T}Ax$ $ dy = dx^{T}Ax + x^{T}Adx = x^{T}(A+A^{T})dx$ (using trace property of matrices) $ dy = (\nabla y)^{T} dx $ and because the rule is true for all $dx$ $ \nabla y = x^{T}(A+A^{T})$   It seems that in step 2, some form of product rule for differentials is applied. I am familiar with product rule for single variable calculus, but I am not understanding how product rule was applied to a multi-variate function expressed in matrix form.  It would be great if somebody could point me to a mathematical theorem that allows Step 2 in the above proof.  Thanks! Ajay

It's stated that the gradient of:  $$\frac{1}{2}x^TAx - b^Tx +c$$  is   $$\frac{1}{2}A^Tx + \frac{1}{2}Ax - b$$  How do you grind out this equation? Or specifically, how do you get from $x^TAx$ to $A^Tx + Ax$?


I have a Dell laptop with fingerprint reader built in. I just ran  with  the following result:  Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 006: ID 138a:00a6 Validity Sensors, Inc. Bus 001 Device 005: ID 0cf3:e009 Atheros Communications, Inc. Bus 001 Device 004: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller Bus 001 Device 003: ID 0bda:5689 Realtek Semiconductor Corp. Bus 001 Device 002: ID 04ca:00ac Lite-On Technology Corp. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub  Is it possible to use fingerprint scanning instead of traditional login with 18.04 and Unity ?

I have Dell Vostro 14 with OS Ubuntu 18.04.  I tried   sudo apt install -y fprintd libpam-fprintd   but not able to use fingerprint reader of my laptop.


How to install Ubuntu 18.10 on an Alienware 15?  I've encountered an error with the touchpad not working, and the noveau graphics driver being insufficient for Steam.

I would like to see a full how-to guide on how to install Ubuntu.


I bought a used iPhone 5 today. When I insert a Nano SIM and try to activate it, it says the previous user has locked the phone and that I need to insert a number to get it unlocked.  I bought the phone through an online site olx.com so I am not able to get in touch with the person to get it unlocked.  I hope that the phone was not stolen and sold to me. I have the bill of the phone, the charger, and knowledge that the device is still under warranty.  Any idea on how I can gain access to the device?

I bought a used iPhone 4.  The previous owner re-set the phone, but did not remove the device from their iCloud.  It is asking me for their iCloud information when I try to set-up the phone.  I don't have contact with the previous owner anymore.  Is there a way to remove the device from their iCloud so I can use a new one?


#include <iostream> using namespace std; class A{     public:     A(){         cout << "Hello World";     } }; class B:public A{     public:     B(){         cout << "World";     } }; int main(){     B obj1;     return 0; }  Why does this program print Hello WorldWorld, shouldn't it print World because I have created object of class B, so why is the constructor of A being called?

What are the C++ rules for calling the base class constructor from a derived class? For example, I know in Java, you must do it as the first line of the subclass constructor (and if you don't, an implicit call to a no-arg super constructor is assumed - giving you a compile error if that's missing).


I haven't done any "serious" math in a while and I wanted to get back to it via differential equations. I remember very well the different methods to solve various sorts of linear ODEs, but I can't remember or even find online any information about the proofs of these methods. I'm starting with constant-coefficient linear homogenous ODEs with no Cauchy or boundary condition, and I remember that the solution space of these equations has the same dimensionality as the degree of the ODE. I remember that linear algebra is involved, and I have looked around on the internet for things about differential operators, to no avail (paper didn't get me very far either).  tl;dr : any hints for proving that the solution space of an nth degree constant-coefficient linear homogenous ODE has dimensionality n ? I know it's at least n because I can show n linearly independent solutions (the well-known exponentials).  EDIT : it has been mentionned that this question is similar to . Where I think they differ, in addition to pertaining to different specialisations of ODEs, is that this question asks for an explanation, while I'm looking for a proof. I know the result is true, I just don't remember how to prove it (as a side note, the accepted answer for the aforementionned question does not answer mine).

For an $n$th order differential equation, why are there always $n$ solutions? Why exactly $n$, not $n - 1, n+1$ or infinite many?    Addendum by LePressentiment :   This is motivated by P176 on Strang's Intro to Lin Alg, 4th Ed. An $n$th order differential equation, how many basis functions does it have? I'd guess $n$, because the diffl eqn have $n$ linearly independent solutions (predicated on Julián Aguirre's answer), all of which look to span the nullspace/solution space of the homogeneous ODE.


The attached screenshot says it all. It's like that regardless of the screen orientation, and it's been that way ever since I installed the app.  Thanks, Mike Waters     App Version: 1.0.89 Device Manufacturer: samsung Device Model: SM-T550   OS Version: 6.0.1 (T550XXU1BPK1)

The lines wrap so much on v1.0.85 that only a few items can be displayed.  Edit: This is on the world's most low end tablet, Azpen A727.  Screenshots of the old:    and new, showing loss of quality


I am writing a report with a number of chapters. I would like each chapter to have a figure above the name of it, which differs depending on a chapter. I got a figure to display above the chapter name, but the problem is that the figure will be applied to every page of this specific chapter. I would like the figure to appear only above the chapter name.   I have slightly modified an example from the Overleaf website:  \documentclass[11pt,a4paper]{report}  \usepackage{lipsum} \usepackage{graphicx}  \usepackage{fancyhdr} \pagestyle{fancy} \fancyhead{} \renewcommand{\headrulewidth}{0pt} \renewcommand{\footrulewidth}{0pt} \setlength\headheight{80.0pt} \addtolength{\textheight}{-80.0pt} \chead{\includegraphics[width=\textwidth]{figure1.png}}  \begin{document} \title{Title here}  \date{September 2013} \author{Jesper Jensen} \maketitle  \chapter{First Chapter Title} \thispagestyle{fancy} \lipsum[1-12]  \chapter{Second Chapter Title} \fancyhead{} \chead{\includegraphics[width=\textwidth]{figure2.png}} \thispagestyle{fancy} \lipsum[1-12]  \end{document}

In a book, with the book documentclass, I'm typesetting I want to include a figure above the \chapter title. This however has turned out to be hard. With the following code:  \chapter{Uppväxt}  \begin{figure}[ht] \includegraphics[width=\textwidth]{bilder/hus.jpg} \end{figure}  \noindent \lipsum   Produces the following result:   Placing \figure above \chapter results in the image being put on the previous page due to the \clearduble command of \chapter, which is desirable for the rest of the book. Changing the options of \figure to [t] results in the figure being included on the next page. It seems like no other combination of positioning options seems to help either.  Can anyone think up a way of placing the figure above the chapter?


I am not a native speaker but both sounds good to me. Which one should be more accurate or in fact correct.

Is the preposition in universal in conjunction with the verb ‘to work’ and can it be used with any organizations and businesses?  For example:        He works as a cook in a local hotel near here.   He works in an office in Chicago.   She works in a big company.   She works in the emergency unit at the hospital.   She works in a shoe repair shop.   After leaving school, he worked in a restaurant for a year. military hospital.   His sister works in a bank.   She works in a shoe factory.   He works in a steel plant.   She works in a gift store on weekends.   Ann works in a research institute.      When should the prepositions at and for be used? For example:        Barbara works at a travel agency.   She works at the local supermarket.   Now he works for a bank.   I work for a small non-profit organization.      I’ve never heard:     She works for a shoe factory.   But with a law firm it’s OK:     She works for a law firm.   Why?


Inspired by this comic from XKCD:   Is there anything to confirm whether or not falcons exist in the Star Wars Universe? If they don't then what is the in-universe reason for the name of the Millennium Falcon?

I'm particularly interested in how the "Millennium" part pertains to the ship itself. It wouldn't hurt to explain the "Falcon" part either though.


has the Heroic ability:     Whenever you cast a spell that targets War-Wing Siren, put a +1/+1 counter on War-Wing Siren.    states:     "Other Soldier creatures you control get +1/+1 and have vigilance."   With Siren in play under my control, I cast Captain Of Watch. The Captain has an effect on Siren: +1/+1 and vigilance.  Does this count as casting a spell that targets Siren?  Should Siren get a +1/+1 counter?  I see "Target" to mean the recipient of some spell or effect.

Note: this is intended to be a canonical question about whether or not a spell or ability targets so there are multiple sub-questions.   Can Hexproof or Shroud save my creature from ? What about a  that was cast for it's Overload cost? Does shroud prevent me from using the Monstrosity ability of a creature, or from giving it more counters with Proliferate? Can I cast an Aura Enchantment on one of my creatures with Shroud, or an opponent's creature with Hexproof? Or can I use the Equip ability to attach an equipment to one of my creatures with Shroud? Will 's ability trigger when my opponent plays ? And will I have to sacrifice my  if my opponent casts ? Will Shroud or Hexproof prevent an opponent from choosing me with 's ability? Will Hexproof keep one of my creatures from being affected by ? If an Aura or Equipment is attached to a creature with Hexproof, does the Hexproof protect the attached permanent?


I have the following code  public static void main(String... args) {      String s = "abc";     System.out.println(s.hashCode());     String s1 = " abc ";     System.out.println(s1.hashCode());     String s2 = s.trim();     System.out.println(s2.hashCode());     String s3 = s1.trim();     System.out.println(s3.hashCode());     System.out.println();     System.out.println(s == s1);     System.out.println(s == s2);     System.out.println(s == s3); }   OP:   96354 32539678 96354 96354  false   -- Correct true    -- This means s and s2 are references to the same String object "abc" . false   -- s3=s1.trim()... which means s3="abc" yet s==s3 fails.. If the above conditon were to be considered (s==s2 is true..) , this should also be true..    Why am i getting "false" when i check s==s3 ?..

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?


I am trying to experiment with objects -- I want an object that can count the number of instances there are.  My code:  class Location:     count = 0      def __init__(self, column, row):         self.column = column         self.row = row         self.num = Location.count         Location.count += 1      def position(self):         print("Col: %i, Row: %i, Instance: %i" % (self.column, self.row, self.num))   # set up grid grid = [[0]*5]*5  # Create objects in all positions for i in range(0, len(grid)):     for j in range(0, len(grid[i])):         grid[i][j] = Location(i, j)         grid[i][j].position()  #prints correctly    for i in range(0, len(grid)):     for j in range(0, len(grid[i])):         grid[i][j].position()  #prints incorrectly -- WHY?!?!   Why does it, when printing the contents of the grid the second time, show completely the wrong data?  I am essentially creating a grid of instances of an object class.  I ant to be able to keep track of the number of instances in this object.  This code is not for anything in particular -- just for my own enjoyment and learning!  edit**  OUTPUT OF CODE:  Col: 0, Row: 0, Instance: 0 Col: 0, Row: 1, Instance: 1 Col: 0, Row: 2, Instance: 2 Col: 0, Row: 3, Instance: 3 Col: 0, Row: 4, Instance: 4 Col: 1, Row: 0, Instance: 5 Col: 1, Row: 1, Instance: 6 Col: 1, Row: 2, Instance: 7 Col: 1, Row: 3, Instance: 8 Col: 1, Row: 4, Instance: 9 Col: 2, Row: 0, Instance: 10 Col: 2, Row: 1, Instance: 11 Col: 2, Row: 2, Instance: 12 Col: 2, Row: 3, Instance: 13 Col: 2, Row: 4, Instance: 14 Col: 3, Row: 0, Instance: 15 Col: 3, Row: 1, Instance: 16 Col: 3, Row: 2, Instance: 17 Col: 3, Row: 3, Instance: 18 Col: 3, Row: 4, Instance: 19 Col: 4, Row: 0, Instance: 20 Col: 4, Row: 1, Instance: 21 Col: 4, Row: 2, Instance: 22 Col: 4, Row: 3, Instance: 23 Col: 4, Row: 4, Instance: 24 Col: 4, Row: 0, Instance: 20 Col: 4, Row: 1, Instance: 21 Col: 4, Row: 2, Instance: 22 Col: 4, Row: 3, Instance: 23 Col: 4, Row: 4, Instance: 24 Col: 4, Row: 0, Instance: 20 Col: 4, Row: 1, Instance: 21 Col: 4, Row: 2, Instance: 22 Col: 4, Row: 3, Instance: 23 Col: 4, Row: 4, Instance: 24 Col: 4, Row: 0, Instance: 20 Col: 4, Row: 1, Instance: 21 Col: 4, Row: 2, Instance: 22 Col: 4, Row: 3, Instance: 23 Col: 4, Row: 4, Instance: 24 Col: 4, Row: 0, Instance: 20 Col: 4, Row: 1, Instance: 21 Col: 4, Row: 2, Instance: 22 Col: 4, Row: 3, Instance: 23 Col: 4, Row: 4, Instance: 24 Col: 4, Row: 0, Instance: 20 Col: 4, Row: 1, Instance: 21 Col: 4, Row: 2, Instance: 22 Col: 4, Row: 3, Instance: 23 Col: 4, Row: 4, Instance: 24   Thanks

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


This is one thing I never really bothered looking into, but have always been unsure of.     punching, kicking, slapping or slashing [is/are] strictly prohibited   That's what I'm trying to determine. Let's say multiple of these specified actions can occur simultaneously. Is it proper to use "is" or "are"?  This is going to be used in a short legal notice.

Can anyone tell me if I should use inspire or inspires in this phrase?     An extraordinary leader whose vision, values, integrity and boundless curiosity inspires all who follow in his footsteps.


If I am given to find a $\gcd$ and I can see a common divisor, can I divide it to make the problem smaller? if so what do I do with the common divisor?  In the case of $\gcd(2780,785)$ I can see the $5$ is a common divisor, and let $\gcd(556,157)=a$ what will be the $\gcd(2780,785)$?

How would you go about proving that $$\gcd \left(\frac{a}{\gcd (a,b)},\frac{b}{\gcd (a,b)}\right)=1$$  for any two integers $a$ and $b$?  Intuitively it is true because when you divide $a$ and $b$ by $\gcd(a,b)$ you cancel out any common factors between them resulting in them becoming coprime. However, how would you prove this rigorously and mathematically?


I want to change my link from usercp.php?do=our_pics&p=$i to usercp/our_pics/1.  I have this .htaccess code  RewriteEngine On RewriteRule usercp/(.*)/(.*) usercp.php?do=$1&p=$2   The problem is when I using the pagination to change the page to another, it doing redirect to main page or page 1, and that because there are problem in mod_rewrite code .  "Edit 1"    After enable RewriteLog and RewriteLogLevel 2, the following is the content of rewrite.log file When the problem occurs.  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#ec2180/initial] (2) [perdir C:/Program Files/wamp/www/ebdaa_v3/] rewrite 'usercp/our_pics/3' -> 'usercp.php?do=our_pics/3'  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#ec2180/initial] (2) [perdir C:/Program Files/wamp/www/ebdaa_v3/] strip document_root prefix: C:/Program Files/wamp/www/ebdaa_v3/usercp.php -> /ebdaa_v3/usercp.php  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#ec2180/initial] (1) [perdir C:/Program Files/wamp/www/ebdaa_v3/] internal redirect with /ebdaa_v3/usercp.php [INTERNAL REDIRECT]  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#724160/initial/redir#1] (1) [perdir C:/Program Files/wamp/www/ebdaa_v3/] pass through C:/Program Files/wamp/www/ebdaa_v3/usercp.php  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#ec6190/initial] (2) [perdir C:/Program Files/wamp/www/ebdaa_v3/] rewrite 'usercp/mainpage' -> 'usercp.php?do=mainpage'  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#ec6190/initial] (2) [perdir C:/Program Files/wamp/www/ebdaa_v3/] strip document_root prefix: C:/Program Files/wamp/www/ebdaa_v3/usercp.php -> /ebdaa_v3/usercp.php  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#ec6190/initial] (1) [perdir C:/Program Files/wamp/www/ebdaa_v3/] internal redirect with /ebdaa_v3/usercp.php [INTERNAL REDIRECT]  127.0.0.1 - - [06/Jan/2013:20:37:26 +0200] [localhost/sid#6828d0][rid#727158/initial/redir#1] (1) [perdir C:/Program Files/wamp/www/ebdaa_v3/] pass through C:/Program Files/wamp/www/ebdaa_v3/usercp.php

This is a  about  the use of a *AMPP's stack.    I recently had a talk with some experienced people and they suggested to me not to use a WAMP stack, and instead install apache, mysql and php separately.  I don't understand why they have suggested this, though, so can anyone tell me?  Is there a particular disadvantage of WAMP, or a particular advantage to installing all of them separately?  Since a WAMP stack itself is composed of apache, mysql and php, then what's the difference between using the WAMP stack and installing them all separately?


I just took a car loan. The amount financed is $12,865.57, the APR is 3.06%, and the length is 48 months.    The finance company charges $285.47 monthly. I would like to know how they calculated such monthly payment?

Specifically, I notice that on a mortgage statement, my payment is "amortized" so that at the beginning of the loan, I am paying almost entirely interest and very little principal.  However, on a credit card balance, it seems interest is only charged on the balance.  Why do amortization schedules work the way they do, and are they typically used for most loans, and why?


I am still using ubuntu 17.04 (Because some features were not working in 17.10). Now I want to upgrade to 18.04. But update manager is showing that "Upgrade from zesty to bionic is not supported with this tool." When tried to upgrade from terminal, it is also showing the same. What can I do now ?

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


Could you help me understand the meaning of "be it practices" in the context below?     People will always find some aspect of another culture distasteful, be it practices, a way of treating friends or relatives, or simply a food that they can not manage to get down with a smile.

What does be it mean in this context and what kind of sentence is this? (grammatically)     There is no one in our society who is not ethnocentric to some degree, no matter how liberal and open-minded he or she might claim to be. People will always find some aspect of another culture distasteful, be it practices, a way of treating or relatives, or simply a food that they cannot manage to get down with a smile.


Python's  module lets you search for files matching a particular pattern. For example glob.glob("*.jpg") would list all jpegs in the working directory.  A more complex example using the double asterisk ** syntax to search all subfolders of 'pics' for cat photos:  glob.glob("pics/**/*cat*.jpg", recursive=True)   Is there any similar function in .NET?

I don't know if it's legit at StackOverflow to post your own answer to a question, but I saw nobody had asked this already.  I went looking for a C# Glob and didn't find one, so I wrote one that others might find useful.


I am seeking to run a common Java program in both Windows and Linux.  The program needs to do some things differently on each platform.  So how can / should my Java program detect it is running under Linux vs. Windows?

I would like to determine the operating system of the host that my Java program is running programmatically (for example: I would like to be able to load different properties based on whether I am on a Windows or Unix platform). What is the safest way to do this with 100% reliability?


I have windows 7 already installed on my computer but I need to reinstall it. I have no data on my windows and I do not care if anything happens to the old windows, but I need to keep my ubuntu safe! I will appreciate if you help me.

I have dual boot configured with Windows 7 (32bit) and Ubuntu 12.04(64bit). I installed Ubuntu after windows, now my windows is corrupt due to some virus and I need to reinstall it. Currently when I start my PC, grub loader comes up and I need to select Ubuntu or Windows.   I was wondering how can I install windows again and still have my Ubuntu install? Is there a way to do this?  I do not want to install Ubuntu again and lose my settings and data there.   Thanks, Ketan


Serving as as a transitional technique, sound effects / visual effect from the upcoming movie scene will play before its scene is presented.   For example, in this video clip below, around 0:08, sink hole becomes a turning wheel.    Second example:   Two men are having a conversation in a room and when the camera still focuses in this room but sound effect of a steam train starting starts to play; a few seconds later, the camera switches to a train platform.

I know I've noticed this effect many times but I can only think of the most recent example: At the end of a scene, someone (bad) is locked out via mechanical door, and is pressuring the people inside to let him in. As the scene is closing, and we're about to switch to a different setting, a mechanical sounds is played before the current scene is cut, but it's the audio for the next scene, making it feel like that door is opening ("Oh no"), but it's not really. You're just tricked for a moment.   Is there a word or phrase for this technique? Is this just a nuance artistic feature used by a few select directors, or is this a well known, commonly used technique?


I am unsuccessfully trying to implement biblatex in my project, so that I can cite other content. I get an error that looks loke this:  Undefined control sequence. <argument> \mkbibdateapalongextra                                    {year}{month}{day}\iffieldundef {endyear}{... l.15     \printbibliography[heading=bibempty]                                               The control sequence at the end of the top line of your error message was never \def'ed. If you have misspelled it (e.g., `\hobx'), type `I' and the correct spelling (e.g., `I\hbox'). Otherwise just continue, and I'll forget about whatever was undefined.   Can you help me to solve the problem? A minimum code example would look like this:  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{hyperref} \usepackage[style=apa,citestyle=numeric,sorting=nyt,sortcites=true,autopunct=true,hyperref=true,abbreviate=false,backref=true,backend=biber]{biblatex} \addbibresource{bibliography.bib} % BibTeX bibliography file \defbibheading{bibempty}{}  \begin{document}     My text with a cite\cite{1_nielsen_2011}.      \printbibliography[heading=bibempty] \end{document}   And the bibliography.bib file has this content:  @misc{1_nielsen_2011, author={Nielsen, Oskar Herrik}, title={Oldmoney.dk | Din genvej til gamle penge}, url={http://www.oldmoney.dk/}, urldate={2015-9-11}, journal={Oldmoney.dk}, year={2011} }

I'm having trouble getting basic APA bibliographies to work. The same thing works with nejm style, but changing the style to apa gives errors:  ! Undefined control sequence. <argument> \mkbibdateapalongextra  {year}{month}{day}\iffieldundef {endyear}{...  Package biblatex Warning: Macro 'name:apa:last-first' undefined. (biblatex)                Using \newbibmacro.  Package biblatex Warning: Macro 'name:apa:first-last' undefined. (biblatex)                Using \newbibmacro.   I'm using texlive 2012, as you can see I'm using biber, yes, I reran biber, and also tried delting the .bbl file and rerunning tools. My source markup is:  \documentclass[12pt]{article}  \usepackage[hidelinks]{hyperref} \usepackage[backend=biber,style=apa]{biblatex}  \addbibresource{BibResource.bib}  \begin{document}  test\parencite{ormrod2004human}  \clearpage  \printbibliography  \end{document}


I work on a program which saves data in a database when shutting down the program. Now it would be nice if that happend also at a system shutdown. I am curious if this is possible somehow in java 8 (Oracle JDK ). It should work for Ubuntu (16.04 and newer) and Windows 10.  Probably I have to tell the OS somehow to wait till the app finished.

Is there a way for a Java GUI application to respond to system shutdown or logoff events, other than to use JNI?  (On Windows, the JNI would use WM_QUERYENDSESSION, on Linux?)  The method should allow the program to prompt users to save, etc., and then continue the logoff process.


I have a HP Proliant server model DL380 G5. 1 SAS hard drive 72GB and 1 SATA 300gb. Also i have a hp smart array p400 bbwc. (power of bbwc is low also has a warning sign)  I'm trying to install an operating system on this server but when i try to install CentOS via DVD it won't show the hard drive's.  I tried to configure the hard drive's as logical drive's via the hp rom configuration utility. There i have 3 options to create/view/delete array's.  When i tried to install windows server 2012 standard with gui it shows the hard drives but when i try to install the os on the server it says: "We couldn't create a new partition or locate an existing one".  Is there something i am missing? Why won't CentOS detect my hard drives?

I've an HP Proliant DL360 G5 server with two 72gb HDD in RAID and 2 150gb HDD in RAID.  I've Windows Server installed on the 72gB HDD and I'm now trying to overwrite it with a fresh installation of CentOS 7 x64.  When I try to install it it says that I need to manually configure the hard disks but when I open the partitioning tool no HDD are detected. I'm using the ~4GB DVD installer.  How can I fix this problem?


The [title](url) is no longer formatted when the chat post is multi-lined Examples: ,

We've come to rename Markdown to Letdown in the  because it lets you down so often. I've now just found a pattern. It seems markdown . That is, this  Letdown can't cope with multi-line comments. Let's see code?  fails to display code marked as code, while this works  But code works.  Now, I think it would be Ok if you said chat messages shouldn't be multi-line. (Although I'd be a bit annoyed, because I like them.) But if so, please don't render them as multi-line (as is the case with comments), so we aren't tempted to use them.


On my Ubuntu 16.04 I checked the status of saned:  $ sudo service saned status saned.service Loaded: masked (/dev/null; bad) Active: inactive (dead)   I have done this:  sudo add-apt-repository ppa:rolfbensch/sane-release sudo apt-get update   And it's still not working!  What should I do?

I have just bought a shiny new Canon MG6250 multifunction printer/scanner and connected it via LAN. Installing the printing side of things was a breeze, however, I cannot work out how to set up scanning.   I installed the  from Canon's site but when I open GIMP or Simple Scan, they say there is no scanner detected. Using GIMP's 'update scanner list' button to search for the scanner does not find it.  How do I tell Ubuntu, GIMP or Simple Scan to look on the network for the scanner? Is there another utility especially for this?


I have to make a program that interacts with the user interface that ask a user for a number and a base to convert to binary, hex, or octo. I made a program that works but when the user types in "0 0", it is suppose to terminate and end the program. My program on the other hand doesn't do that but keep going in the while loop.   Here is the code:   import java.util.*;  //for Scanner  public class BaseConversionApp { public static void main(String[] args) {     Scanner console = new Scanner(System.in);     String combo = numbers(console);      while(combo != "0 0") {         if(combo.length() > 0) {     //breaks the string into integers to do math to it             Scanner s = new Scanner(combo);             int count = s.nextInt();             int countSecond = s.nextInt();             s.close();             conversion(count,countSecond);             System.out.println();             //now if it goes 0 0 or              String again = numbers(console);             //  conversion(count,countSecond);         }     }   //prompts the user for two numbers and checks if the bases are 16, 8, 2. public static String numbers(Scanner console) {         String combination = "";         String nothing = "0 0";         System.out.print("Enter an integer and the new base: ");         int integer = console.nextInt();         int base = console.nextInt();         if(base == 16 || base == 2 || base == 8) {             combination = integer + " " + base;             return combination;         } else if (base == 0 && integer == 0){             System.out.println("Good bye!");             return nothing;         } else {             System.out.println("Sorry, that is an invalid base. Please enter 2, 8, or 16  only.");         }         return "";     }      //converts the integers into binary, hexa, or octo.     public static void conversion (int integer, int base) {          //takes cares of the special case if the user wants to know hexidecimal         if(base <= 16) {             String calculations = Integer.toString(integer, base);               if(integer > 0 && base > 0) {                 System.out.println(integer + " in binary -> " + Integer.toString(integer,  base));             }         }     } }

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?


How to make a bootable USB. I am using UBUNTU 13.04 LTS and want to make a bootable usb to install windows  Suggest any Ubuntu based usb creators to make a bootable Windows Flash drive.

I'd like to create a Windows bootable USB stick, but I don't have a Windows machine with me at the moment to do so. How could I achieve the same using Ubuntu?


I am nearly at 100% and just need one more gnome! I can’t find gnome #1! Can anyone help?

No matter where I look, I just can't find gnome number [insert number here]. Where can I find every gnome in the game?


I bought an iPad mini (Wifi only) and gave it to my nephew as a gift.  He switched on the device and set it up with his apple ID. He did not set up (Find My iPad/iPhone) feature.  After a month of usage, he noticed the device is heating up when connected to the charger. Suddenly, the device display is off, and can not be charged.  When connected to a USB port on a mac, or PC, it does not get detected.  I tried to hold Power button+Home Button for 10 seconds then releasing the Home button, but it did not work.  I tried to put the device in Recovery Mode, DFU mode, but nothing worked. The device does not get detected by Windows or Mac.  I toke the device to the service center I bought it from (Not an Apple Store, we don't have Apple Stores in Saudi Arabia).   At the service center, they have a policy not to service any iOS device if it is locked using Find My iPhone feature from iCloud.  I told them that the feature was never turned on. They checked  and entered the serial number, and found out that the device [Activation Lock : ON ]. So they asked me to login to icloud using the apple ID that was used to activate the lock and remove the device from [My Devices] in iCloud.  I logged in to icloud.com using my nephew's apple ID, but could not see the iPad in the list of devices.  I thought maybe the activation lock was done using another apple ID, so I tried mine, my brother's, all of the apple IDs I tried, none of them had this iPad listed among the devices in iCloud.  Now, I can not get service for the device because they think I stole the iPad.  Although I have an invoice that proves the purchase.   I know that revealing the apple ID might be considered a breach of security, but if I could just get the first and last letter of the email of Apple ID used to lock the device, then we can reduce our efforts in this hassle.  My question is: how do I know the apple ID that is used to lock the iPad knowing only the serial number of the device?

I got an iPhone 5c off of eBay and I can't tell if it's iCloud locked (Activation Lock) or not because I don't have a SIM card for it yet. It was restored by iTunes with no problems. The phone asks me for my language, country, WiFi, then tells me to insert a SIM. Is it going to tell me I need the previous owners password after I get the SIM card and insert it?


When doing calculations on very large numbers where integral data types such as double or int64 falls short, a separate class to handle such large numbers may be needed.    Does anyone care to offer an efficient algorithm on how best to do this?


The variance is: $$\dfrac{\sum_{i=1}^{n}(x_i-\bar x)^2}{n-1}$$   I read that $n-1$ is used instead of just $n$ when we are measuring the variance of a sample taken from a bigger population. I don't understand why we're subtracting $1$.   Thank you.

Does anyone have an intuitive explanation (no formulas, just words! :D) about the "$n-1$" instead of "$n$" in the unbiased variance estimator $$S_n^2 = \dfrac{\sum\limits_{i = 1}^n \left(X_i-\bar{X}\right)^2}{n-1}?$$


Let $k[x]$ be the vector space of polynomials with only finitely many non-zero coefficients. Define the subspace $U_{f}=k[x]\cdot f$ where $f$ is a monic polynomial of degree n, say $f=a_{0}+\ldots+a_{n-1}x^{n-1}+x^{n}$. I succeeded to show that $\left(1+U_{f},\ldots,x^{n-1}+U_{f}\right)$ is a Basis of $k[x]/U_{f}$ and found out that multiplication by $x$ induces an endomorphism from $k[x]/U_{f}$ to $k[x]/U_{f}$. Furthermore, I found out that the corresponding matrix looks like this: $A=\begin{bmatrix} 0&\cdots&0&0&-a_{0}\\1&0&\cdots&0&-a_{1}\\ 0&1&\ddots&\vdots&-a_{2}\\ \vdots & \ddots& \ddots&0&\vdots \\ 0& \cdots&0&1&-a_{n-1}\end{bmatrix}$. The characteristic polynomial turns out to be just $\chi(\lambda)=(-1)^{n}f(\lambda)$.  My task is to find the minimal polynomial. My intuition tells me that it hast to equal $f$, but somehow I cannot prove it. Can anyone help me out?

of a monic polynomial $f \in \mathbb F\left[x\right]$ in $1$ variable $x$ over a field $\mathbb F$ plays an important role in understanding the structure of finite dimensional $\mathbb F[x]$-modules.  It is an important fact that the characteristic polynomial and the minimal polynomial of $C(f)$ are both equal to $f$. This can be seen quite easily by induction on the degree of $f$.  Does anyone know a different proof of this fact? I would love to see a graph theoretic proof or a non inductive algebraic proof, but I would be happy with anything that makes it seem like more than a coincidence!


What is the word for a person who is always concerned with how people look,  describing outer appearances as a reference to who they are?

I'm looking for a pejorative word that describes one who cares only about their own, and others' appearances, and cares nothing for personality to the point of obsession. Something that fits in like: "The son had inherited his mother's ______". Shallow is not the word I'm looking for - it wouldn't exactly fit in that sentence (and shallowness seems a bit awkward).  Vanity is the closest word I have to a fit, but it only describes an excessive care of oneself, and not others.


I am looking for the name of a  short story, maybe from the early 1950's. I tried most famous authors without success.  Plot: all humans are extinct after a great war (decades ago). Fighting robots are rusting, wearing out, running down, etc. They try to build new robots, but fail: their giant metal claws cannot assemble the tiny parts of a new "brain". One robot tries to touch a butterfly, but crushes it. One by one they all "die".

The story is about 2 war robots who have survived a war that wiped out humanity world-wide.  There may be more of the robots functional elsewhere, but since the long-distance communication robots broke down they have no contact with anyone else.  I don't recall if there was an accompanying illustration or just a description, but I have a mental image of a roughly spherical body with 3 short legs underneath and 2 long arms, terminating in long claws, at opposite points on the midline.  The limbs were segmented, like flexible tubing.  One of the robots is more thoughtful than the other and realises that if they can't find a way to repair themselves they will eventually run down.  It tries to construct a smaller robot with hand-like manipulators instead of the claws they were built with for killing.  Making the critical linkage, its claw accidentally causes a short circuit, slagging the brain and destroying the robot.  In anger and frustration, it shreds the construct and gives up.  In the final scene, the 2 robots are trudging through snow, one of them trailing its no-longer-functional arms.  Its arms snag on an unseen rock and it falls.  It doesn't get up, and the other walks on.  I would have read this story almost 40 years ago, in an anthology from the (then local) library.


While using HTTPS site, all YouTube embedded videos turn into big blank spaces on the page as seen in the image below. Even if the source link is HTTPS, the parser turns it into HTTP for the embedding.    If I edit the elements and replace HTTP with HTTPS within the embedded code, however, the video shows fine:    The embed code should match the protocol used to open the page.

Many SE sites (like math.SE) have a problem with mixed content, which causes display bugs in recent browsers. This is particularly evident with math.SE (because of the huge use of MathJax) and with chat sections.  Will this be fixed?  How to reproduce  Visit  or   What happens  Mixed content is blocked, output is missing pieces of code (MathJax):    This picture also includes my main Firefox addons (top right), it relevant. It shows missing styles:    The white on the left is my tab list.


If I have something like this:  a=['100','200','501','124','1234\n']   How can I remove that '\n' ?

What is the Python equivalent of Perl's chomp function, which removes the last character of a string if it is a newline?


Let $f(X)=X^6+X^3+1\in\mathbb Q[X]$. I need to find a splitting field $L$ for this polynomial and the degree of $[L:\mathbb Q]$.  $f$ is irreducible with $f(X+1)$ and $p=3$ to apply Eisenstein. I know that then $\mathbb Q[X]/(f(X))$ is a field in which $f$ has a root (how can I find out what the root is?). I'm supposed to inductively find more splitting fields and adjoin them in the end to get $L$, but how is that done concretely?

I am trying to find the splitting field of $x^6+x^3+1$ over $\mathbb{Q}$.  Finding the roots of the polynomial is easy (substituting $x^3=t$ , finding the two roots of the polynomial in $t$ and then taking a 3-rd root from each one). The roots can be seen  [if there is a more elegant way of finding the roots it will be nice to hear]  Is is true the that the splitting field is $\mathbb{Q}((-1)^\frac{1}{9})$ ? I think so from the way the roots look, but I am unsure.  Also, I am having trouble finding the minimal polynomial of $(-1)^\frac{1}{9}$, it seems that it would be a polynomial of degree 9, but of course the degree can't be more than 6...can someone please help with this ?


Let us say we have two continuous random variables, $X$ and $Y$ such that their pdfs $f(x)= f(-x)$ and $g(y)= g(-y)$ for all $x$ and $y$. In other words, $X$ and $Y$ have symmetric distributions around 0. Is it possible that joint distribution of $X$ and $Y$ will be such that $f_{joint}(x, y)$ is not always equal to $f_{joint}(-x, -y)$ for all $x$ and $y$? Please provide proof or simple counterexamples, if possible.

Somebody asked me this question in a job interview and I replied that their joint distribution is always Gaussian. I thought that I can always write a bivariate Gaussian with their means and variance and covariances. I am wondering if there can be a case for which the joint probability of two Gaussians is not Gaussian?


I am planning to travel to Holland on my multi entry 3 months visa that was issue by the French embassy in the United Kingdom. I have been to Paris 2 weeks ago for 2 days.

I have requested for a French long term (Type D) student visa from a consulate in India. It's a national Type D visa and not a Schengen visa. My question is that can we still go to other Schengen countries on this visa? If not then can we get a Schengen visa from a consulate in France?


I installed Ubuntu Trusty Tahr 14.04 LTS on a Lenovo Yoga 2 11 and noticed I had no wi-fi option, only networking (usually I see "enable wi-fi" too.)  rfkill list all resulted in only a soft block and after running sudo modprobe -r ideapad-laptop the soft block was removed.  The trouble is that I don't know were to go from here as I still do not have wifi. All of tutorials/docs I have found address what to do if you have a hard block.

I have installed Ubuntu alongside Windows 8.1. But the wifi is not working in Ubuntu (perhaps the drivers are not present), which worked fine in windows. Also I cant connect with Ethernet since my laptop does not have an Ethernet port. So is there any way for me to connect to the internet in ubuntu? Edit: Output of the terminal command  lspci -knn | grep Net -A2:  vikram@vikram-Inspiron-11-3148:~$ lspci -knn | grep Net -A2 01:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)     Subsystem: Dell Device [1028:0018]     Kernel driver in use: bcma-pci-bridge vikram@vikram-Inspiron-11-3148:~$    I did what Pilot6 suggested. Here is the output:    vikram@vikram-Inspiron-11-3148:~$ sudo dpkg -i *.deb [sudo] password for vikram:  Selecting previously unselected package bcmwl-kernel-source. (Reading database ... 163804 files and directories currently installed.) Preparing to unpack bcmwl-kernel-source_6.30.223.141+bdcom-0ubuntu2_amd64.deb ... Unpacking bcmwl-kernel-source (6.30.223.141+bdcom-0ubuntu2) ... Selecting previously unselected package dkms. Preparing to unpack dkms_2.2.0.3-1.1ubuntu5.14.04_all.deb ... Unpacking dkms (2.2.0.3-1.1ubuntu5.14.04) ... Setting up dkms (2.2.0.3-1.1ubuntu5.14.04) ... Setting up bcmwl-kernel-source (6.30.223.141+bdcom-0ubuntu2) ... Loading new bcmwl-6.30.223.141+bdcom DKMS files... First Installation: checking all kernels... Building only for 3.16.0-30-generic Building for architecture x86_64 Building initial module for 3.16.0-30-generic ERROR (dkms apport): kernel package linux-headers-3.16.0-30-generic is not supported Error! Bad return status for module build on kernel: 3.16.0-30-generic (x86_64) Consult /var/lib/dkms/bcmwl/6.30.223.141+bdcom/build/make.log for more information. modprobe: FATAL: Module wl not found. update-initramfs: deferring update (trigger activated) Processing triggers for man-db (2.6.7.1-1ubuntu1) ... Processing triggers for initramfs-tools (0.103ubuntu4.2) ... update-initramfs: Generating /boot/initrd.img-3.16.0-30-generic vikram@vikram-Inspiron-11-3148:~$


I'm facing some problem in my LaTeX code: \documentclass[twocolumn,pra,aps,showpacs,reprint,nofootinbib]{revtex4-1} \usepackage{amsmath,mathrsfs,amsbsy,color,graphicx,bm,amsthm,amsfonts} \usepackage{times} \usepackage{ulem} \usepackage{braket} \usepackage{physics} \usepackage{anyfontsize} \usepackage{enumitem} \usepackage{graphicx} %Para usar pt-br com RevTex4 \usepackage[utf8]{inputenc} \usepackage[brazilian]{babel}  \usepackage{mathtools} % Para indentar o primeiro parágrafo \usepackage{indentfirst}   \urlstyle{same}  \begin{document}         \title{ \Large{Title} %english title         \\      \large{subtitle}}         \author{ person 1 }         \email{email  1}           \author{ person 2 }         \email{email 2}                   \affiliation{affiliation}  \end{document}  When I run this code, I get the authors' names as "person 1 and person 2", but I want it to be "person 1, person 2", with a comma between the names. How can I do this?

Basically I'm trying to separate multiple authors names using a comma instead of 'and', here's what I'm doing...  \documentclass[aps,prl,a4paper,twocolumn,superscriptaddress,notitlepage]{revtex4-1} \usepackage{amsmath} \usepackage{mathtools} \begin{document} \author{Thing One} \author{Thing Two} \affiliation{Working here} \maketitle \end{document}   Which at the moment prints Thing One and Thing Two, instead of spacing them by a comma... Thing One, Thing Two. Any help is much appreciated!


In windows you can undo an operation if you press CTRL+Z. E.g. you delete a file in the gui then press CTRL+Z and the file will be restored and appears in the folder again.  Is there something similar in linux but with commands?! E.g. i accidentially unzipped a file, and i want to undo the operation (all files should dissapear again).

I was wondering if there is a (simple) possibility to redo/reverse a command that was executed in the bash shell? (to make it undone)  Is there something similar to the ctrl+z combination to redo any action (for example in word or LibreOffice)?


The plot was that people from the future did extensive research and then made one small change to the past (like moving an object from one side of a room to another) that resulted in a major shift in the future story arc.   Any ideas would be most welcome!

I originally read this book in the mid- to late '70s.   The premise was a bureaucracy whose job it was to manipulate events in human history by making the smallest possible change that would effect the desired outcome. Not time cops in the sense of going after law breakers.  The intent was to maintain a policy of non-interference as much as possible but when interference was warranted then to make the least possible change and to do so invisibly.  For example, they might take someone's keys off the dresser and put them just out of sight underneath the dresser where they plausibly might have fallen.  The subject would never know of the manipulation but would then be delayed getting out of the house and the ripples grew from there to avert a war or otherwise affect events on a large scale.  After reading that, whenever I would lose something - especially in an improbable way such as dropping a screw at my feet and then finding it on the other side of the room half an hour later - I would take some consolation in the thought that I had just averted some global catastrophe.  I was pretty scatterbrained as a kid (we call that ADHD nowadays) so I experienced this a lot.  Given that I've spent so much time pondering the ideas from the book, I'd love to re-read it.


I have set up a Wordpress multisite install, with two blogs - let's call them site1.com and site2.com .  When I access  the 'Forgot your password link' points to , which is quite confusing.  How can I fix the link to point to point to site2.com?

I have a multisite network. I want my users to be able to reset their passwords while staying within their subsites. So for example clicking the "lost your password?" link keeps them within their subdomain (subdomain.domain.com/wp-login.php?action=lostpassword) as opposed to taking them to the main site (domain.com/wp-login.php?action=lostpassword).  After they submit the username or email to reset the password, I would like for that email to contain links back to their subdomain and not the main site as is the default functionality.   Prior to the 4.0 update I was able to use this patch  and ultimately this plugin  to get the exact functionality described above. All was great.  However after the update it is no longer working. Asking for assistance in the various places referenced has still not helped solve the problem. Is anyone able to help?


i have used BC547 Transistor to stepup from 4.6v but I can't able to draw above 5v from collector, I have given input of 4.6v to base and emitter to ground and collector to output load. but load doesn't activate. Can anyone help me out from this problem?

I'm not very pratical as I just started learning electronics and I'm planning to make some experiment with Raspberry Pi.  I'm trying to control a 5v relay board that, I think, is made for Arduino, as Raspberry only has 3.3v GPIO.  It's active low, as GPIO.LOW activates the relay, and the 3.3v keep it active too, so I think I'll need exactly 5v to turn it off.  So, basically I think I'll need a transistor, with the base controlled by my GPIO, that will activate a 5v line to Input line of the relay switch.  I have thought about these schematics, but I've been told it will burn my transistor as I need a resistor between 5v and the transistor collector.  My question is certainly basic, but... WHY?  When no current flow through base there will be no problem, when the transistor gets activated isn't my load the relay board? Why do I need other resistors?  Thanks in advance.    This is the relay board I bought, I couldn't find schemas, so I can't provide more.


Is it ever correct to say "Me and Jon are going to the movies"?

I've always been taught to put myself last when referring to myself in the same sentence as others but the usage of "me and..." seems to be everywhere these days. The misuse of the word "me" instead of "I" aside, is there some new rule I haven't heard of? Shouldn't we put ourselves last regardless of the "me"/"I" usage?  Examples of "correct" usage:      My friends and I went for some ice   cream. Did you see my friends and me   at the ice cream stand?   Examples of "incorrect" usage:     Me and my friends went for some ice   cream. Did you see me and my friends   at the ice cream stand?   Note: I was also taught that the only person who could put themselves first was the queen.


I have thousands of episodes that I want to rename which are all in a similair format.  This would take a really long time if I had to do it manually.  So I'll need a simple way to batch rename the following examples:  [Source]SeriesName_-_001_EpisodeName_[480p][DVD][Uploader]  [Source]SeriesName_-_010_EpisodeName_[720p][BD][Uploader]  [Source]SeriesName_-_100_EpisodeName_[1080p][BD][Uploader]  to just:  SeriesName Episode 1 - EpisodeName  SeriesName Episode 10 - EpisodeName  SeriesName Episode 100 - EpisodeName  How would I be able to achieve this?

I've got a bunch of files named with a the pattern 99 - DescriptiveName.txt and I'd like to remove the number from the front so I just have DescriptiveName.txt.  How can I do this? Can I do it from the command line or is there a utility that can do this?


I have been thinking about what would happen if by chance the photons collided with each other. I heard once that electromagnetic waves pass through each other without any interference.  I wanted to know if I am correct?  Does the collision produce sound?

Could someone explain to me what the collision of two photons would look like? Will they behave like,   Electromagnetic waves: they will interfere with each other and keep their wave nature Particles: they will bounce like classical balls   I assume that energy of that system is too small to make creation of pairs possible.


I am creating a program to solve sudoku which contains a struct for each cell that contains the value of the cell and all possible values for the cell as an int with each bit corresponding to a possible value.  To update every cell I have a function called applyMask which removes the bit corresponding to the number of the cell from all other cells that are affected by this cell. This function works properly in testing however when I loop through all cells a large number is passed instead of the correct number. For example, it will pass x  is 0 and y is 2 properly but then instead of passing x is 0 and y is 3 next it will pass x is 4199111 and y is 1. In gdb, the function is passed x is 0 and y is 3 however upon stepping into the function it says that x is 4199111 and y is 1. The function called:  typedef struct Cell {   int values;     int value; } cell;  void getSection(int pos, int *section1, int *section2) {   switch(pos % 3){     case 0:         *section1 = pos + 1;         *section2 = pos + 2;     case 1:         *section1 = pos - 1;         *section2 = pos + 1;     case 2:         *section1 = pos - 2;         *section2 = pos - 1;     } }  void applyMask(cell sudokuBoard[9][9], int x, int y) {   int mask = ~(1<<(sudokuBoard[x][y].value-1));      for(int maskP = 0; maskP < 9; maskP++)     {   sudokuBoard[maskP][y].values &= mask;         sudokuBoard[x][maskP].values &= mask;     }      int sectionX1;     int sectionX2;     getSection(x, &sectionX1, &sectionX2);     int sectionY1;     int sectionY2;     getSection(y, &sectionY1, &sectionY2);      sudokuBoard[sectionX1][sectionY1].values &= mask;     sudokuBoard[sectionX1][sectionY2].values &= mask;     sudokuBoard[sectionX2][sectionY1].values &= mask;     sudokuBoard[sectionX2][sectionY2].values &= mask; }   And is called by  for(int i = 0; i < 9; i++)     for(int j = 0; j < 9; j++)         applyMask(sudokuBoard, i, j);

Given a simple switch statement  switch (int) {     case 1 :     {         printf("1\n");         break;     }      case 2 :      {         printf("2\n");     }      case 3 :      {         printf("3\n");     } }   The absence of a break statement in case 2, implies that execution will continue inside the code for case 3. This is not an accident; it was designed that way. Why was this decisions made? What benefit does this provide vs. having an automatic break semantic for the blocks? What was the rationale?


I want to put logo at top right corner in beamer, maybe just align with the title line but should not depended on title bar exist or not :-).  For reference, is to put logo at the bottom line.  Current code as below:  \documentclass[t]{beamer} \beamertemplatenavigationsymbolsempty \setbeamertemplate{footline}[frame number] \logo{\makebox[1\paperwidth]{\includegraphics[width=.5cm,keepaspectratio]{logo.png}}}  \begin{document}  \begin{frame}[c]{Hello world} \begin{itemize} \item item 1 \item item 2 \item item 3 \end{itemize} \end{frame}  \end{document}   Current output is:

I am making a presentation using beamer, and I want to be able to position a certain image the way I want in a frame. I am not sure how to do that. Is there some way you can specify coordinates in the frame and then set an image there?  Is there a better way to place images in various places with the beamer class?


If $x$ and $A$ are positive and $x_1 = \frac{1}{2}(x + A/x)$,$x_2 = \frac{1}{2}(x_1 + A/x_1)$, and so forth, prove that the sequence $x_n$    is convergent and determine its limit.  Use your result to find an approximation to $\sqrt2$  My attempt:  To prove the convergence: I showed that since $x_n = \frac{1}{2}(x_{n-1} + A/x_{n-1}) \geq \sqrt{A}$ using the geometric-arithmetic inequality that $x_n$ is bounded below.  Then, I did $x_{n+1}-x_{n}=\frac{1}{2}(A/x_{n}-x_n) \leq 0 $ using the fact that $x_n \geq \sqrt{A} \space for \space all\space  n$  Which implies that $x_n$ is monotone decreasing. So we can conclude that it is convergent.  But how can I get an approximation of $\sqrt2$ using my result?  Any help would be appreciated. Thank you!

For any $a > 0$, I have to show the sequence $x_{n+1}$ $=$  $ \frac 12$($x_n+ $ $ \frac {a} {x_n}$)  converges to the square root of $a$ for any $x_1>0$.  If I assume the limit exists ( denoted by $x$) then,  $x$ $=$  $ \frac 12$($x+ $ $ \frac {a} {x}$) can be solved to $x^2 = a$  How could I show that it does exist?


How do I go about getting the surface area of an object in cm^2 in blender ? Is there a tab I can find it or will it require a script?. Any help would be appreciated

How do I get the surface area of a mesh? Preferably no python involved.


Article class. XeLaTeX compiler. I want the titles of parts to appear in the TOC only (not in the document itself). Is this possible?

I wonder how I can add a \part entry to the TOC without any output in the the document itself. I actually got a nearly working version:  \begin{filecontents}{chap1.tex} \chapter{Chapter} This is a chapter. \end{filecontents} \begin{filecontents}{chap2.tex} \chapter{Chapter} This is a chapter. \end{filecontents}  \documentclass{scrbook}  \usepackage{xparse,hyperref}  \NewDocumentCommand{\TOCpart}{s m}{%    \clearpage    \refstepcounter{part}%    \phantomsection    \addcontentsline{toc}{part}{%       \IfBooleanF{#1}{\protect\numberline{\thepart}}%       #2%    }%    \cleardoublepage    \ignorespaces }  \begin{document} \tableofcontents \part{Normal Part} \include{chap1}  \TOCpart{TOC Part} \include{chap2}  \part{Normal Part} \chapter{Chapter} This is a chapter.  \TOCpart{TOC Part} \chapter{Chapter} This is a chapter. \end{document}   This works except that “II. TOC Part” should be listed with page 7 instead of 6. I.e. with the same one as the following chapter. If I change the definition to  \NewDocumentCommand{\TOCpart}{s m}{%    \cleardoublepage    \refstepcounter{part}%    \phantomsection    \addcontentsline{toc}{part}{%       \IfBooleanF{#1}{\protect\numberline{\thepart}}%       #2%    }% %   \cleardoublepage    \ignorespaces }   The entry has the right page number but if followed by an \include it appears behind the chapter entry, which is pretty wrong … so how can I combine the two definitions to get the part before the chapter but with the chapter’s page number, while still using \include and don’t moving \TOCpart inside of the included file?


Suppose that $\sum \limits_{n=1}^{\infty}a_n$ series with positive terms which diverges then series $\sum \limits_{n=1}^{\infty}\dfrac{a_n}{a_1+a_2+\dots+a_n}$ also diverges.  Can anyone show how to prove it? Unfortunately i have no ideas

So I've been trying to figure out how to prove the following.     Let $(a_n)$ be a sequence of positive numbers such that $\sum\limits_{n=1}^\infty a_n =\infty$, and define $s_n=\sum\limits_{i=1}^n a_i$. Then $\sum\limits_{n=1}^\infty\frac{a_n}{s_n} =\infty$ as well.   I can prove it by comparing it to $\int_1^\infty \frac{1}{x} \, dx $ if the sequence $a_n$ is bounded by some $M$, but that's as far as I've been able to get.


Where did the word "noggin" originate? My daughter was talking to her friend and the expression "your noggin" was used. Then one had asked the other, "where did that phrase come from originally?"

I find myself using the phrase "that's using your noggin" in various situations, even though English is not my native language. Most likely I picked it up watching some tv show.  I understand that "noggin" means head, but it seems strange that "that's using your noggin" should be in widespread (in America, I assume) use, although it's not only used in this context.  What is the origin of this expression?


I've been following the Android Studio training tutorial on the official Android Dev site to create a simple "messaging" app (). I reached the end of "Building my first app". When I click the "send button" the app crashes, the contents of the message are irrelevant. I've tried it on my phone and the emulator.  Here's the error code:   E/AndroidRuntime: FATAL EXCEPTION: main Process: com.john.myfirstapp, PID: 3180 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.john.myfirstapp/com.john.myfirstapp.DisplayMessageActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2327)    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)    at android.app.ActivityThread.-wrap11(ActivityThread.java)    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)    at android.os.Handler.dispatchMessage(Handler.java:102)    at android.os.Looper.loop(Looper.java:148)    at android.app.ActivityThread.main(ActivityThread.java:5417)    at java.lang.reflect.Method.invoke(Native Method)    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference    at com.john.myfirstapp.DisplayMessageActivity.<init>(DisplayMessageActivity.java:16)    at java.lang.Class.newInstance(Native Method)    at android.app.Instrumentation.newActivity(Instrumentation.java:1067)    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2317)    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)     at android.app.ActivityThread.-wrap11(ActivityThread.java)     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)     at android.os.Handler.dispatchMessage(Handler.java:102)     at android.os.Looper.loop(Looper.java:148)     at android.app.ActivityThread.main(ActivityThread.java:5417)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)   Android Studio also gave me a suggestion on this line:     getSupportActionBar().setDisplayHomeAsUpEnabled(true);   It states:      Method invocation 'getSupportActionBar().setDisplayHomeAsUpEnabled(true)' may produce 'java.lang.NullPointerException'   I'm quite sure that it isn't some small mistake like a curly or missing quote.   Any help is appreciated :)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


$f,g$ are entire function satisfies $|f|\le |g|$ what is the relation between them?  I did $h(z)={f\over g}$, Then $|h|\le 1$ so $h$ is bounded, entire(?) and so constant?  $h$ could possibly have poles at  which $g(z)=0$, :(  Thank you for help.

These two questions I didn't even find the way to solve So please if you can help   Suppose $f (z)$ is entire with $|f(z)| \le |\exp(z)|$ for every $z$ I want to prove that $f(z) = k\exp(z)$  for some $|k| \le 1$ Can a non constant entire function be bounded in half a plane? Prove if yes , example if not.


I want my image to look like image 1, but when I render, the result is image 2. Why is the viewport different to the rendered output?

I position my camera close to my object. In "Camera Persp" I see my object very close. This is what I want. Now when I hit F12 to render my object, but it always renders from a wrong distance/position further away.  What setting might I have accidentally enabled?


If gravitons are particles, how do they escape BH gravity if nothing can? So are the gravitons really particles or is there really just/only curvature of space-time?

My understanding is that light can not escape from within a black hole (within the event horizon).  I've also heard that information cannot propagate faster than the speed of light.  It would seem to me that the gravitational attraction caused by a black hole carries information about the amount of mass within the black hole.  So, how does this information escape?  Looking at it from a particle point of view: do the gravitons (should they exist) travel faster than the photons?


In my program I need to create a dll file in run-time and need to save it in a specific file location. when i create this dll file in run-time i need to pass a parameter and that parameter will be stored inside dll file and automatically it will copy into specific location. How can i do it with c#. need some guide. thanks.

Currently I have some code that is being generated dynamically.  In other words, a C# .cs file is created dynamically by the program, and the intention is to include this C# file in another project.  The challenge is that I would like to generate a .DLL file instead of generating a C# .cs file so that it could be referenced by any kind of .NET application (not only C#) and therefore be more useful.


I consider a situation in a system in which an observer is sitting in body of mass $M$ and another observer in a body of mass $2M$, both moving with velocity $v$ towards each other. If observers in each body consider themselves at rest and the other one is in motion, total energy calculated by the first observer is $\frac{2M(2v)^2}{2}$ but for the second observer it is $\frac{M(2v)^2}{2}$ which is half of the first. How am I getting different total energy of system at same instant?

I'm having problems understanding the following situation. Suppose two 1-tonne cars are going with the same orientations but opposite senses, each 50 km/h with respect to the road. Then the total energy is   $$\begin{eqnarray}E=E_1+E_2&=&\frac{1\mathrm t\times(50\mathrm{km}/\mathrm h)^2}2+\frac{1\mathrm t\times(50\mathrm{km}/\mathrm h)^2}2\\&=&1\mathrm t\times(50\mathrm{km}/\mathrm h)^2\\&=&2500\frac{\mathrm t\times\mathrm{km}^2}{\mathrm h^2}.\end{eqnarray}$$  Now if we look at it from the point of view of one of the cars, then the total energy is   $$\begin{eqnarray}E=E_1+E_2&=&\frac{1\mathrm t\times(0\mathrm{km}/\mathrm h)^2}2+\frac{1\mathrm t\times(100\mathrm{km}/\mathrm h)^2}2\\&=&\frac{1\mathrm t\times(100\mathrm{km}/\mathrm h)^2}2\\&=&5000\frac{\mathrm t\times\mathrm{km}^2}{\mathrm h^2}.\end{eqnarray}.$$  I know that kinetic energy is supposed to change when I change the frame of reference. But I understand that then there must be some other kind of energy to make up for it so that the energy in the system stays unchanged. But I don't see any other kind of energy here. I only see two total energies of the same system that seem to be different. Could you explain this to me?  Please note that while I don't understand any physics, I do understand college level mathematics, so if necessary please use it. (I doubt anything more than high school maths should be needed here, but I want to say this just in case.)


My girlfriend would like to take up road cycling and join me, but hasn't had a road bike before me. So, I'm gleefully eyeing up an excuse to go bike shopping :-)  I'm used to the idea that road bikes are also offered in 'women-specific' frames - not as in the old style with the lower crossbar, but a different geometry to an otherwise standard two triangle frame. When reading up, it seems this can be significantly a smaller frame - which wouldn't be an obvious benefit for her, because we're both 5'9 give or take and fairly similarly proportioned.  I know why women-specific saddles are a thing, but they're an easy swap at a friendly bike shop. Is there any other reason why a 'mens' frame wouldn't be perfectly good for her?

Why do women's bikes have a diagonal bar in the frame instead of a horizontal frame? Is this the only difference?  Sorry if this has been asked (but I cannot find it by searching) and I also just cannot think of a reason why.


I want to align equations inside an enumeration, so I use the aligned environment and its [t] option to make the first equation appear on the same baseline as the item label:  \documentclass{article} \usepackage{amsmath, enumitem}  \begin{document} \begin{enumerate}[align=left, leftmargin=*, label=\large\sffamily\bfseries \alph*)]   \item $a = 1$   \item   $   \begin{aligned}[t]     a &= 1\\     b &= 2\\     c &= 3   \end{aligned}   $ \end{enumerate} \end{document}   This works quite well, but I noticed that the aligned environment introduces a small indentation (I added the red line for better visualization):    How can this be solved? Or is there an even better alternative to aligned?

Near the beginning of the definition of the amsmath environments aligned and gathered (and also mathtools' multlined) there's an explicit thin space \,. This often  has to be cancelled  with  \!, as has been observed  various  times:         I'd like to know why this explicit \, is there – what would go wrong without it?    From amsmath.dtx:  \newcommand{\start@aligned}[2]{%     \RIfM@\else         \nonmatherr@{\begin{\@currenvir}}%     \fi     \savecolumn@ % Assumption: called inside a group %    \end{macrocode} %    The \cs{null} here is to keep the \cs{,} glue from causing the %    invocation of the clause in \tex/'s built-in tag placement %    algorithm that can cause an equation to be shifted all the way over %    to the margin. %    \begin{macrocode}     \null\,%


For a given power, which will be larger, a motor or a generator? Is there a certain relationship between motor/generator size and power?

Its in the title.  I'm just curious and it turns out that either this is such a stupid question that no one has bothered to answer it, or i'm just not good at googling today.  I guess I'm thinking specifically about the permanent magnet synchronous motor (PMSM) in my car, but any answer however general would interest me.


When you pass variables in Javascript functions, what is the difference between '$name' and 'name'.  For example,  var myFunction = function(name){   name.a = "a";  };  var myFunction = function($name){   $name.b = "b"; };

I quite often see JavaScript with variables that start with a dollar sign. When/why would you choose to prefix a variable in this way?  (I'm not asking about $('p.foo') syntax that you see in jQuery and others, but normal variables like $name and $order)


I am facing a odd issue. The problem is that I am unable to material preview or even can't render. When I press Z and drag over these option, model become dull and no material can be previewed.

I don't know why but now, when i go in material preview or rendered (in solid mode it works fine), my object is entirely gray, or invisible idk, because it has the same color of the background. I've been working for days on this project without having this issue, it suddenly showed up. I tried opening other old projects and suddenly they all do the same so i guess it is some blender program setting that applies for all the projects, but idk how it happened cuz i didn't change anything :/, anyone got any tips?


I still don't have a clear approach, but this is what I see.  $m \mid b$ and $m \mid a$ or $m\nmid b$ and $m\nmid a$.  I may think that the way is showing $\gcd(a,m)\leq\gcd(b,m)$ and $\gcd(a,m)\geq\gcd(b,m)$

My problem is how to somehow relate the the gcd and congruence. I know that $(a,b) = ax + by$. I also know that $a \equiv b \pmod n$ means $n\mid a-b$. Any hints?  Thanks!


I noticed that someone asked a  on how to consume C# COM component in C++  But that thread is marked as duplicate because the title of question is too generic and does not specify C#.  Since I am not able to answer that question, I am creating this new question which I'll answer and others can also put forward there suggestions

I'm relatively new to the Component Object Model specification - I have a simple question:    How can I access a COM interface from a C or C++ application    For instance, accessing Microsoft Excel COM interface to perform basic operations, without user intervention.  Kind regards


I know that you can use reflection in Java to get the name of class, methods, fields...etc at run time.  I was wondering can a method figure out its own name while its inside it's self? Also, I don't want to pass the name of the method as a String parameter either.  For example  public void HelloMyNameIs() {   String thisMethodNameIS = //Do something, so the variable equals the method name HelloMyNameIs.  }   If it that is possible, I was thinking it would probably involve using reflection, but maybe it doesn't.  If anybody know, it would be greatly appreciated.

Is there a way to get the name of the currently executing method in Java?


I am making a New Year Standee and would like to know what the bleed space should be. I am making the creative in Illustrator. Kindly help

I'm starting to do designs meant for printing, but I'm fairly new to this medium so I don't really understand how bleed works and how much bleed should I specify for:   Business cards Large format prints (42 inches and bigger) Magazines   Should I extend the design into the bleed areas?


I have the model of a man formed by jacket, trousers, shoes, hands and head, all joined with CTRL J. When I go to create the armor he gives me "heat-weighting-failed-to-find-solution-for-one-or-more-bones". I tried to apply the scale, rotation, and location but nothing. I tried to remove doubles but nothing, and I even deleted a lot of faces, vertices and edges. I don't know what to do anymore!

Here is the .  Picture:   It's nothing special but I cant figure out why I get problems rigging this mesh. It would be important and a great Help! Thanks for reading and I know there are a lot of guides answering this question but I tried all and it doesn't seem to work.


For some reason, I discovered I have an old iCloud email that is associated with my account. However, the section of the email before the domain (XXXX@icloud.com) is based on a retired AOL email that I haven't used in about 10 years. How do I either delete this email from my account (unsure what this is associated with as a side note, my Apple ID?) or change this email if I am forced to keep it?

When I was married I started both my @me.com and @icloud.com accounts.  The accounts are my first name and last (previously married) name run together.  Now that I am divorced I don't want that as my email.  I would rather have a different name at the front of my email.  How do I go about changing both accounts to another name and getting all my devices and itunes accounts moved over.


I'm writing a program that keeps track of team names and how many times that team has won a game based on user input. I need to allow for the user to input a String (for the team name) and an x to exit. I need to be able to compare a string and a character in a while loop (while (String != x)). So far I've tried:  char exitProgram = 'x'; String x = Character.toString(exitProgram); while (winningTeam != x)   as well as:  while (winningTeam.charAt(0) != 'x')   However, neither of these result in a while loop that exits when x is entered. I'm not sure if it's a problem with trying to turn a char into a String or if I'm doing something else wrong but I'm pretty sure it's something I'm not understanding with the comparison. Any help is appreciated.  Edit: This has been marked as a duplicate of   and while they're similar, I believe my question differs in needing to know how to compare a character to a string (i.e finding the correct character to string conversion) rather than just comparing two strings.

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?


In the perturbative QCD, specific partonic distribution functions (pdf) linear combination is called "flavor singlet" or "flavor nonsinglet" combination.  What is the combination, and why are they called flavor "singlet" or "non-singlet" combination? Does evolution equation (DGLAP equation) of these specific linear combination of pdf functions take a particular form?

I don't get a grip of what that exactly means. What IS an abstract singlet, doublet,... under $SU(N)$ or other groups?


I just noticed this (on , but seemingly applying to all Community-deleted posts):    This is awesome, and I'm concerned that it's an oversight and is meant only to be enabled for developers.  If it was an oversight... can we please keep it? Humanizing the deletion reasons would be great, but even in its current form I want it to stay.

they were question banned; it turned out it (in part) it was because of deleted questions.   was deleted by the Community user.  I'm aware it will delete old posts that have a negative score, but for a minute or two, I was really puzzled as to why it was unilaterally deleted without some notation left.  Can we have the Community user leave a notation in a post's history as to why the post was deleted?    Something like the following would suffice:     Post deleted automatically due to having negative votes and no activity for three months


It could sound like Samson is hardworking because of the 'not',  but it can also sound like Samson isn't hardworking because of the 'like'. So is Samson hardworking or not? Thank you! :)

I am confused about the usage of the words like and unlike in sentences. Like and unlike make me confused because I see them being used everywhere almost interchangeably, and to make matters worse I even saw commas making difference in meaning.  Which of the following sentences is most correct, and least ambiguous?      Unlike Xbox, Playstation can't play Halo.     Playstation can't play Halo unlike Xbox can.     Playstation can't play Halo, unlike Xbox can.     Like Xbox, Playstation can't play Halo.     Playstation can't play Halo like Xbox can.     Playstation can't play Halo, like Xbox can.     Playstation can't play Halo unlike Xbox.     Playstation can't play Halo, unlike Xbox.     Playstation can't play Halo like Xbox.     Playstation can't play Halo, like Xbox.    In case you don't know what I actually wanted to say in those sentences: I'm trying to say that Playstation can't run the Halo video game and Xbox can run that game. I probably should have tried sentences with no brands but I can't imagine any meaningful sentences at this moment which contains like/unlike.