Why do some people with a lot of reputation have a diamond and 'moderator' next to their name. If it is to do with the amount of reputation then how much reputation do you need?

Some people have a diamond after their username (e.g. )    What special privileges do diamond moderators have? How can I become a diamond moderator? Who are the diamond moderators?  How many are there?      For more information, see  in the .     Note: not to confuse with certain Stack Exchange employees, for example  members or "community managers", who often have diamonds as well, but are not ordinary moderators.


I installed the deb files of Fpdb (a poker analysis tool); and i downloaded the program. The problem is that when i try to run it from the terminal i get this: "ImportError: No module named pygtk "; I tried to re install and update pygtk but i can't solve the problem.   thanks in advance for any suggestion;  c

after the  a few hours back I managed to get a working desktop after using an ethernet cable and sudo apt-get install ubuntu-desktop  But now when I try to run ubuntu software center from CLI this is what I get   rick@Abigail:~$ sudo software-center  Traceback (most recent call last):   File "/usr/bin/software-center", line 34, in <module>     import gtk ImportError: No module named gtk   Any guesses how to fix this. The search box on synaptic is also missing. It has something to do with module named axi. I think the both are related.


For instance, when I come to site superuser.com, I would like to temporarily allow ajax.googleapis.com - but just on this site, not anywhere else.  I know this can be done permanently (), but I would like these permissions to be temporary. Can this be done?

Some forums allow direct embedding of YouTube videos, and this is slowing down my browsing a lot when a user posts several videos in a single post. I want to allow scripts from YouTube only on youtube.com, not anywhere else.  I also want to disable social network tracking so that scripts from sites like Facebook are only allowed on their home domain. How do I set up a blacklist with exceptions or a whitelist with conditions?


So I would like to present data using a color plot subdivided into squares. For a large data set, it is easy to use a 3D plot with surf, however when there is not so much information, this does not work so nicely.  Take for example:  \begin{tikzpicture} \begin{axis}[view={0}{90}]     \addplot3 [surf]         coordinates {             (0, 0, 1) (1, 0, 9) (2, 0, 3)              (0, 1, 4) (1, 1, 5) (2, 1, 6)              (0, 2, 7) (1, 2, 2) (2, 2, 9)}; \end{axis} \end{tikzpicture}     I have 9 data points, and 4 squares are displayed which reduces greatly the amount of data displayed.  An alternative I thought of was to use square marks  \begin{tikzpicture} \begin{axis}[view={0}{90}, enlargelimits=.3]     \addplot3 [scatter, mark=square*, mark size=24pt]         coordinates {             (0, 0, 1) (1, 0, 9) (2, 0, 3)              (0, 1, 4) (1, 1, 5) (2, 1, 6)              (0, 2, 7) (1, 2, 2) (2, 2, 9)}; \end{axis} \end{tikzpicture}     but the result is less than pleasing, and would require a lot of mucking around with the size of the marks.  The only "alternative" is to use interpolation so that at the vertices the correct color is displayed  \begin{tikzpicture} \begin{axis}[view={0}{90}]     \addplot3 [surf, shader=interp]         coordinates {             (0, 0, 1) (1, 0, 9) (2, 0, 3)              (0, 1, 4) (1, 1, 5) (2, 1, 6)              (0, 2, 7) (1, 2, 2) (2, 2, 9)}; \end{axis} \end{tikzpicture}  \begin{tikzpicture} \begin{axis}[view={0}{90}]     \addplot3 [surf, shader=interp, patch type=bilinear]         coordinates {             (0, 0, 1) (1, 0, 9) (2, 0, 3)              (0, 1, 4) (1, 1, 5) (2, 1, 6)              (0, 2, 7) (1, 2, 2) (2, 2, 9)}; \end{axis} \end{tikzpicture}     But without the correct interpolation, looks ugly. Besides, it doesn't exactly fix the problem of displaying only 9 data points.  So for small data sets, is there a way of plotting exactly the same number of squares as required?

I have a matrix of size MxN and I want to make a surface plot directly from above so that each cell in the matrix is drawn as a square. None of the pgfplots shaders really do what I want, since they draw squares between the cells of the matrix (i.e. a 3x3 matrix ends up as 2x2 cells when plotted). The example hopefully makes it clearer:  \documentclass{article}  \usepackage{fullpage} \usepackage{tikz} \usepackage{pgfplots} \usepackage{pgfplotstable}  \pgfplotstableread{         0 0 0         0 1 1         0 2 2          1 0 3         1 1 4         1 2 5          2 0 6         2 1 7         2 2 8 }\data  \begin{document} \foreach \shader in {interp, flat, flat corner} { \begin{tikzpicture} \begin{axis}[         title={\texttt{\shader}},         title style={                 at={(0.5, 1.5)},                 anchor=north,         },         width=.3\linewidth,         view={0}{90},         colormap/hot2,         colorbar horizontal,         colorbar style={                 at={(0.5, 1.02)},                 anchor=south,                 xticklabel pos=upper,         }, ] \addplot3 [surf, shader=\shader] table {\data}; \end{axis} \end{tikzpicture} } \end{document}      How do I arrange my data so that each cell in the matrix is drawn as a separate cell in the output?  EDIT: I realised after entering the question that the answer is very simple, so I'll just answer this myself.


We know that $\sum_{k=1}^{\infty}\frac{1}{k}=\frac{1}{1}+\frac{1}{2}+\frac{1}{3}+\cdots$ diverges.  But for any natural number $n$, $\sum_{k=1}^{n}\frac{1}{k}$ is finite.  The question is; how to compute $\sum_{k=1}^{n}\frac{1}{k}$ for sum natural number $n$, explicitly?  Say $n=50$, how to compute $\frac{1}{1}+\frac{1}{2}+\frac{1}{3}+\cdots+\frac{1}{49}+\frac{1}{50}$, explicitly?

How do I calculate sum of a finite harmonic series of the following form? $$\sum_{k=a}^{b} \frac{1}{k} = \frac{1}{a} + \frac{1}{a+1} + \frac{1}{a+2} + \cdots + \frac{1}{b}$$ Is there a general formula for this? How can we approach this if not?


I have noticed that in some cases "what you want to do" to an object is written before the object while other times the object is written first.  here is an example   dictionary = {}  dictionary["ole"] = 28 dictionary["maria"] = 26 dictionary["kim"] = 6 dictionary["lucy"] = 1  print(dictionary.keys()) # object first (dictionary)  print(sorted(dictionary)) # object after (sorted()) is first   How do I know when the object should be before "what I want to do with it" or after?

Can someone provide a simple explanation of methods vs. functions in OOP context?


i am bit week in regex.i am trying to validate phone no by regex & jquery and it works when i am giving phone number like +4401634687222 or 3301634687222. basically phone number may look like below and those no are valid.  +44 (0) 1634 687222 +44(0)1634687222 4401634687222 25805487   here is my code for validation.  var regEx = '1?\W*([2-9][0-8][0-9])\W*([2-9][0-9]{2})\W*([0-9]{4})(\se?x?t?(\d*))?'; var val = jQuery.trim($("input[id*='txtEnqphone']").val()) if (!val.match(regEx)) {     if ($('#Enquery_feed_loader').html() != '') {         $('#Enquery_feed_loader').fadeOut('slow', function () {             $('#Enquery_feed_loader').html('' + dialog_Msg.Invalid_Phone + '');         }).fadeIn('slow');     } else {         $('#Enquery_feed_loader').fadeOut('slow', function () {             $('#Enquery_feed_loader').html('' + dialog_Msg.Invalid_Phone + '');         }).fadeIn('slow');     }      $("input[id*='txtEnqphone']").focus()     flag = false;     return false; }   so just change my regex expression as a result i can enter the above phone number. thanks

I'm trying to put together a comprehensive regex to validate phone numbers. Ideally it would handle international formats, but it must handle US formats, including the following:   1-234-567-8901 1-234-567-8901 x1234 1-234-567-8901 ext1234 1 (234) 567-8901 1.234.567.8901 1/234/567/8901 12345678901   I'll answer with my current attempt, but I'm hoping somebody has something better and/or more elegant.


With a two-party system, our nation will divide the people (who/whom)   most need to be brought together.   Do I use who or whom for this sentence?  I think that "people" is the direct object and warrants the use of "whom", but I want to make sure I'm right.

They interviewed several candidates who he thought had the experience and qualifications he required.   My test prep book says this should be "who" because of the subordinate clause's predicate:     They interviewed several candidates who he thought had the experience and qualifications he required.   I feel like it should be "whom" as it's the object of the main clause.     The interviewed several candidates whom he thought had the experience and qualifications he required.   Who's right?


There are trillions of stars like the Sun in our universe so "why is it space is dark and cool?" Well I really meant that our stars, giant balls of gases which exist by expelling huge amount of energy in the form of heat and light. So my question is:  Why space is dark even though there are stars like sun in our space giving huge of bright light? where does these energy goes? well I meant i.e for example take the planet earth the one side of the which faces the sun is bright and hotter than the earth but another is the opposite so my question is  even though there are so many stars in our universe why the space is like the side of the earth that does not faces the sun?

Of course there is pretty hot stuff too. For example Suns.  But isn't the vacuum of space the perfect containment for heat? And shouldn't the rare collision with particles even heat up an object that floats around in space?  Why aren't they hot from time to time? Is it because they loose their heat by radiant heat?  And if so does radiant heat emission always occur until the object is the same temperature as the surrounding or does it depend on other factors?


I was trying out some queries in Data Explorer and noticed that, column CreationDate in table Votes doesn't contain the full timestamp. Only the date part is present and time part is set to 00:00:00. Have a look at . It would be nice to have the full timestamp. Possible uses of this are determining how many votes are cast immediately after posting, how many are cast within an hour, and so on. I read  where Greg makes the point that:  up/down voting patterns could strongly correlate with other activity on the site (questions, answers, comments).  But, all these details about posts, comments are available with exact timestamp in User's profile as well as in Data Explorer. The exact voting timestamp can be seen in the Reputation tab. So, if I want to guess who voted me, I can do so by looking at this data. Having exact voting timestamp in Data Explorer won't provide any extra information to aid guessing.

Is there a particular reason why vote times are omitted in the data dump?  IMO this could be a very useful data-set. Is this one of the steps that was done to anonymize the data, or does it simply not exist? This would be a very good addition to future dumps to help build time-based relationships, which are currently very rigid and full of assumptions.


Since a part of Voldemort is within Quirrell, doesn't that make him a horcrux by definition as well?

From HP :     J. K. Rowling revealed in Pottermore that Prof. Quirinus Quirrell served as a temporary Horcrux when Voldemort's soul possessed his body during Harry Potter's first year at Hogwarts. (source: )   QUESTION:  Seeing how at that point Quirrell was inhabited by the "main" fragment of Voldemort's soul (and that fact was something 100% clear and obvious from "HP&SS" book), does the statement above mean that somehow there actually were *two fragments of it in Quirrell, one "main" and one "Horcrux"?* If not, then what's the "reveal" part?


If $N$ is a normed a linear space, then its dual vector space $N^*$ is always complete.  Attempt: Let $\{f_n\}$ be a Cauchy sequence in $N^*$. Then, for some $\varepsilon > 0$, there exists $m,n \in \mathbb{N}$ such that $\|f_n - f_m \| < \varepsilon$. The way to show that the limit lies in $N^*$ would be to show that $f_n(x)$ converges in $K = \mathbb{C}$ or $\mathbb{R}$. How do I show that the limit of linear functionals is still a linear functional?

As in the introduction of dual norm by Wiki, it says dual normed space $X'$ is always complete.  How to prove that? or at least explain that?  We all know the normed vector space is not always complete; if complete, all Cauchy sequences convergent. However, dual normed vector space is complete?


There are time dependent & space dependent systems (magnetic fields) and time independent (particle in a box or harmonic oscillator). In the latter the expectation value is the 'average' energy and it works out nicely, but does this apply even if the Hamiltonian is dependent on time? because you don't have a nicely worked out energy value (as with the oscillator) but regardless of what the energy actually looks like is the expectation value the same that is it the total energy?

I thought the Hamiltonian was always equal to the total energy of a system but have read that this isn't always true. Is there an example of this and does the Hamiltonian have a physical interpretation in such a case?


I want to add label "Algorithm" to the numbering of list of algorithms, e.g.,    Algorithm 1. Search Algorithm 2. Sort   I tried different solutions found here but does not work.  The main .tex file is here:  \documentclass[PhD]{msu-thesis} \usepackage{algorithmic} \usepackage{algorithm}  \title{Contributions to Computer-Aided Diagnosis of Prostate Cancer in Histopathology} \author{Kien Nguyen} \date{2013}  \begin{document}  \frontmatter  \maketitlepage  \include{Chapter_UpdateJune/abstract}  \clearpage  \include{Chapter_UpdateJune/acknowledgement} \SingleSpacing \clearpage \listoftables \clearpage \listoffigures \clearpage \listofalgorithms %\addtocontents{loa}{\def\string\figurename{Algorithm}} %\renewcommand*{\thealgocf}{Algorithm~\arabic{algocf}} %\addcontentsline{toc}{chapter}{List of Algorithms} \mainmatter %\include{Chapter_UpdateJune/ch1_intro_v2} \include{Chapter_UpdateJune/ch2_glandseg_v7} %\include{Chapter_UpdateJune/ch3_imageclassify} %\include{Chapter_UpdateJune/ch3_nucleibased_v2} %\include{Chapter_UpdateJune/ch4_retrieval_v2} %\include{Chapter_UpdateJune/ch5_cytology_v3} %\include{Chapter_UpdateJune/ch6_summary} \backmatter \makebibliographycover \SingleSpacing \bibliography{FullBib} \bibliographystyle{IEEEbib}  \end{document}    Thanks

I'm trying to add the word "Algorithm" before each entry in the List of Algorithms (because of unavoidable thesis guidelines).   I saw similar questions but the solutions listed there don't work for me. I'm not sure about reopening those questions, hence posting it separately. Apologize if that's not the right etiquette.     (I'm using "algorithm" package instead of "algorithm2e")   (not sure if solutions listed there require other packages as listed solutions don't work for me)  Current output:  List of Algorithms 1 Optimization . . . . . . . . 3   Desired output:  List of Algorithms Algorithm 1 Optimization . . . . . . . . 3   Here's a simplified code sample that illustrates the issue. Your help is much appreciated. Please let me know how to get desired behavior for this sample.  \documentclass[letter,10pt]{book}                                                                                \usepackage[utf8x]{inputenc}  \usepackage[breaklinks]{hyperref} \usepackage{algorithm} \usepackage{algorithmic}  \title{Sample book} \begin{document} \listofalgorithms  \chapter{Sample} % Outline \begin{algorithm}[!hbt]     \centering     \caption{Optimization}\label{alg:pso}     \begin{algorithmic}[1]         \STATE \textit{GenerateInitialPopulation}(pop)         \FOR {particle $ \leftarrow $ 1 \textit{to} numParticles}           \STATE \textit{Evaluate}(particle)         \ENDFOR     \end{algorithmic} \end{algorithm}  \end{document}


I am planning on wiring 4 pin momentary push switch button that has a LED as well. The switch itself is fine with 20V, but the only problem is that the power source input is 20V and the LED requires 12V.How should I lower the voltage?  I was thinking of a voltage regulator, but I thought it is easier to work with color coded resistors, since I will be working on tight space. Now I salvaged the resistors and found 47Ohm and 33.4Ohm resistors.  When I did the simple math   $$ V_{DIV} = 20V * {47 \over (47+33.4)} = 11.6915V $$  which is \$ 0.3V \$ lower than \$ 12V \$. Is this okay to be used?  Bear in mind I'm a newbie.

I am designing a circuit for SIM900 and PIC MCU. I am facing few problem on power supply for them. I will be giving 12v to the circuit. Now PIC works on 5volts and SIM900 works on 3.2v - 4.8v. At first I thought of using two different voltage regulators. But Now i am using 7805 to convert 12v to 5v and then using a voltage divider to convert 5v to 4v. Below is the schematic:    Here input voltage is 12v and using 7805 to convert it to 5v which will be given to PIC MCU. This 5v is also used in voltage divider circuit to convert it to 4v for SIM900. I have used R1=100 and R2=400 for voltage divider circuit. Is this circuit safe to use. Does voltage divider circuits are good to use. Please help. Thanks.!


I am asking to what extent this problem is true:     Uncountable product of separable spaces is separable.   I need these statements to be explained if possible:   How to construct a countable subset of uncountable product of separable spaces. Counterexample for the contradicted case.

I already figured out how to show that the countable product of separable topological spaces is separable,  but I'm out of ideas when the index set has cardinality of $\mathfrak c$. My textbook says it is possible but gives no references. Any suggestions how to prove this statement?  In a less general setting, I would also be interested to see how a dense countable set is constructed to $\mathbb{R}^{\mathbb{R}}$. Thanks in advance.


I have an enum type with some discontinued values for each enum. When I try to cast an int value to the enum type it returns with multiple enum values seperated with the | operator. Can anyone explain this logic of how it is cast?  enum EnumTest {     Test1 = 0,     Test2 = 1,     Test3 = 1 << 1,     Test4 = 1 << 2,     Test5 = 1 << 12,     Test6 = 1 << 13,     Test7 = 1 << 20,     Test8 = 1 << 22,     Test9 = 1 << 23,     Test10 = 1 << 24,     Test11 = 1 << 25,     Test12 = 1 << 14,     Test13 = 1 << 15,     Test14 = 1 << 16,     Test15 = 1 << 25,     Test16 = 1 << 17,     Test17 = 1 << 18,     Test18 = 1 << 19,     Test19 = 1 << 21,     Test20 = 1 << 26 }  public void method1() {     int number=67239937;     EnumTest e = (EnumTest)number; //output: Test2|Test16|Test20 }

From time to time I see an enum like the following:  [Flags] public enum Options  {     None    = 0,     Option1 = 1,     Option2 = 2,     Option3 = 4,     Option4 = 8 }   I don't understand what exactly the [Flags] attribute does.  Anyone have a good explanation or example they could post?


What do you call this thing (on the picture)? Laundry and water is put in it.

I got the large round container without a lid, used for washing clothes in the below picture. But I don't know how to call it.     What do you name that plastic washing container?    A plastic washing tub, a plastic basin or something?


Apart from their nature and the medium utilized, what are the differences between an EM wave and a wave we see in a pond?  When we throw a stone into a pond, can we imagine we are observing light propagating through space or are we missing something?

I have a life science degree and even worked in research for a few years. So I feel I should be able to answer this question for myself, but yesterday my daughter blindsided me by asking why, if sound and light are both waves, light can travel through the vacuum of space but sounds can't?  So, I told her that one was a mechanical wave and other was an electromagnetic wave and ... then realised that was the extent of my knowledge. I was parroting stuff I'd learn years ago without any real understanding.  Can someone explain to me, ideally with science but without maths:   what the difference is? why one requires a medium for propagation and the other doesn't? how come electromagnetic waves can still propagate via a medium (i.e. heat waves still carry heat energy through air, or the body)? whether all electromagnetic waves are quantized (i.e. light waves are made of photons but ... heat waves are too, right?) whether it's possible for a wave of each type to exist at the same wavelength?   EDIT: stepping back, it appears I have caused confusion born of ignorance. Essentially, while I can understand the properties of a mechanical wave simply by observing it, I am struggling to understand how intangible things like heat and light can have the same properties.


I was contemplating about the path I am headed on as a programmer and wanted some advice on it. Where should I post a question asking for advice related to it? About where to learn stuff from and stuff like that.

Where should I post question like:     Where can I find books on [some programing subject]?   or      Online sources for learning  [some programing technique]?   ? ? Should it be community wiki? or is it a taboo in the ?


I have been using win 7 but recently i had this desire of installing Ubuntu, so I tried installing it alongside Windows but due to having dynamic volumes I was unable to install it. Therefore, I formatted the whole system and installed Ubuntu 13.04.  Now the problem is when I was installing Ubuntu , it didn't ask for disk partitioning and just installed. So now when I installed GParted in Ubuntu, I got this result.    So now firstly I need to know what this means?? Please answer comparing with Windows because I am new to Ubuntu.   And secondly, can I partition this space into volumes like we have in Windows?  Sorry if I have been not clear....  Would be thankful for any views...  Thanks a lot in advance.

I've got Ubuntu 10.10 installed to use my whole hard-disk, but would like to use the 130GB of free space I've got to create a new partition and do some development on Unity and Natty.  Can I use gparted to do this?  If so how?


While receiving a phone call, the man on the other end of the call was looking for another woman. When finished asking for her, he said: "Are you she?" I've always heard "Are you her" and this was a first for me. "Are you she?"... is it proper English?

I have 3 questions regarding she/her and my logic is posted below:   Only one of the contestants was chosen, she/her.   I think the answer is "she" and here's my logic:  This sentence is written in the passive voice so the subject no longer "does" an action or "is" something, but rather is acted upon. "One" is the simple subject here despite the fact that she is not choosing.  And I believe the "she/her" is an appositive that's placed at the end of the sentence instead of placed right next to the word it's describing; therefore, the proper pronoun here is "she" because subjects take the nominative case. If I place the pronoun right after "one of the contestants", "she" would be the appropriate appositive here in formal language.   "Only one of the contestants, she, was chosen"   Was it she/her you hoped to find?   I think it's "she" because "she" is a predicate nominative here so it takes the subject form in formal language. If I mess with the syntax, I can get the following:   "It was she you hoped to find."   In this rearranged sentence, "she" is the predicate nominative and takes the subject case, while "you hoped to find" is just some adjective clause describing this woman.    Congratulations on beating everyone else in the Pokemon League...but there's still one more opponent left--me!"    I'm assuming the "me" part is shortened for "It is me" In that case, I would go with "I" because it's the predicate nominative of the clause.  Do we choose "me" or "I" in this sentence? "Me" sounds better, but is there some rule here I'm missing?  -  I'm not sure if my reasoning is entirely correct. Thanks in advance.  Link on Predicate Nominatives:


This is on an S7 Edge.  I do not have this phone in my possession.  This is from a screen shot of a text they sent.  This "fish" icon was in the notification bar at the top left. I have searched in reverse image and cannot get an app name.  Does anyone recognize this icon?   Thank you

I'm concerned about an app on my child's phone. I saw an app icon in the notification area that looked strange (Andy Android head, slightly tilted as its icon).  How can I find out what app it is from just having seen that icon in the notification bar?


Let $X$ be a connected space that admits universal covering $E$ and $f:X \to X $ an homeomorphism . Now let’s call $Y=(X\times [0,1])/\sim$ where $\sim$ is the relation generated by $(0,x)\sim(1,f(x))$ for all $x\in X$. The request is to show that the fundamental group of $Y$ is a semidirect product between the fundamental group of $X$ and $\Bbb Z$. I tried to demonstrate the normality of $\Bbb Z$ in $\pi_1 (Y)$ but I didn’t reach any result. Any hint or solution will be very appreciated!

Let $f\colon X\to X$ be a homeomorphism between a CW-complex $X$ and iteself.  Let $M_f=X\times [0,1]/(x,0)\sim (f(x),1)$, mapping torus of $X$ from $f$.  I want to calculate the fundamental group $\pi_1(M_f)$ of $M_f$ in terms of $\pi_1(X)$ and $f_*\colon \pi_1(X)\to \pi_1(X)$.  Are there any hint to do this?  Note: This is not a homework problem.


Can you explain why there is no need for the auxiliary verb to be before related in the following sentence:  Do you have any information related to the book?   What kind of grammar rules are applied in situations like this?

What is the part of speech of 'regarded' in the following?     "a quality of beauty and intensity of emotion regarded as characteristic of poems"    Why isn't it "... [which is] regarded ..."?  And in another case:      "a small lizard with wide feet, found especially in warm countries"     And also:      "Words used to describe writing or speech style"    In all these examples, why shouldn't the verbs be in their passive form (e.g. which is found, words that are used)?   I am a ESL learner and I am very confused by these usages!


I have some images on my drive that are persisting after an operating system install and multiple high strength drive wipes. Programs like Cipher and CCleaner aren't effective. The partition is small and I've filled it up with images in an attempt to overwrite the old ones, but the new ones instead of the deleted ones are wiped by a format/reinstall of Windows 7.

I know that on the windows operating system, when you delete a file it's still recoverable.  I'd like to avoid simply paving the harddrive with zeros as I would like to keep my OS installation as is, but is there a way to truly delete files that have been previously deleted?


Any suggestion/hint, not the whole solution, how to determine convergence/divergence of $$ \sum_{n=1}^{\infty}\dfrac{e^n \cdot n!}{n^n} $$ I'm currently stuck.

I want to find the convergence interval of the infinite series $\sum\limits_{n=0}^\infty \dfrac{n!x^n}{n^n}$. I will use the ratio test: if I call $u_n = \dfrac{n!x^n}{n^n}$, the ratio test says that, if the following is true for some values of $x$, the series will be convergent for these values of $x$: $$\lim_{n\to+\infty}\left|\frac{u_{n+1}}{u_n}\right|<1$$ So, I will first calculate the value of $\left|\dfrac{u_{n+1}}{u_n}\right|$: $$\left|\dfrac{\dfrac{(n+1)!x^{n+1}}{(n+1)^{n+1}}}{\dfrac{n!x^n}{n^n}}\right|=\dfrac{(n+1)!|x|^{n+1}}{(n+1)^{n+1}}\times\dfrac{n^n}{n!|x|^n}=\frac{(n+1)n^n|x|}{(n+1)^{n+1}}=|x|\left(\frac{n}{n+1}\right)^n$$ So, $\lim\limits_{n\to+\infty}\left|\dfrac{u_{n+1}}{u_n}\right|$ becomes: $$\lim_{n\to+\infty}\left|\frac{u_{n+1}}{u_n}\right|=\lim_{n\to+\infty}|x|\left(\frac{n}{n+1}\right)^n=|x|\lim_{n\to+\infty}\left(\frac{n}{n+1}\right)^n$$ Now I must evaluate the value of $\lim\limits_{n\to+\infty}\left(\dfrac{n}{n+1}\right)^n$. For this, let $y = \left(\dfrac{n}{n+1}\right)^n$; so, instead of calculating $\lim\limits_{n\to+\infty}y$, I will first calculate $\lim\limits_{n\to+\infty}\ln y$: $$\lim_{n\to+\infty}\ln y=\lim_{n\to+\infty}\ln \left(\dfrac{n}{n+1}\right)^n=\lim_{n\to+\infty}n\ln\left(\frac{n}{n+1}\right) =\lim_{n\to+\infty}\frac{\ln\left(\frac{n}{n+1}\right)}{\frac{1}{n}}$$ Applying L'Hôpital's rule: $$\lim_{n\to+\infty}\frac{\ln\left(\frac{n}{n+1}\right)}{\frac{1}{n}} =\lim_{n\to+\infty}\frac{\frac{1}{n(n+1)}}{-\frac{1}{n^2}} =\lim_{n\to+\infty}\left(-\frac{n}{n+1}\right)=-1$$ Now, since we know that $\lim\limits_{n\to+\infty}\ln y = -1$, we have that: $$\lim_{n\to+\infty}y=\lim_{n\to+\infty}e^{\ln y} = e^{-1} = \frac{1}{e}$$. Substituting this back into the expression $\lim\limits_{n\to+\infty}\left|\frac{u_{n+1}}{u_n}\right| = |x|\lim\limits_{n\to+\infty}\left(\frac{n}{n+1}\right)^n$, we have that the limit of $\left|\dfrac{u_{n+1}}{u_n}\right|$ as $n\to+\infty$ is: $$\lim_{n\to+\infty}\left|\frac{u_{n+1}}{u_n}\right|=\frac{|x|}{e}$$ Therefore, the series will certainly be convergent for the values of $x$ for which $\dfrac{|x|}{e}<1$, that is, $|x|<e$. So, I know that the series is convergent for $-e < x < e$, but I have to test whether the series is convergent at $x = e$ or $x = -e$. That is, I have to test whether $\sum\limits_{n=0}^{\infty} \dfrac{n!e^n}{n^n}$ and $\sum\limits_{n=0}^{\infty} \dfrac{(-1)^nn!e^n}{n^n}$ are convergent. Since these limits don't approach zero, I know they are both divergent, but I'm not sure how to find the limits, because of the factorial function. Also, I can't use integral test here, because of the factorial. Probably I should use comparison test, but I haven't found any divergent series to which to compare it. Any hints? Thank you in advance.  Edit: Using the suggestion by Ragib Zaman in the answer below, since the Taylor polynomial $P_n(x)$ of $e^x$ at $a=0$ is $$e^x = 1 + x + \dfrac{x^2}{2!} + \cdots + \dfrac{x^n}{n!}+\cdots,$$ if we substitute $n$ for $x$ we see that $e^n>\dfrac{n^n}{n!}$; therefore, $\dfrac{n!e^n}{n^n} > 1$, and, thus, we show that $\sum\limits_{n=0}^{\infty} \dfrac{n!e^n}{n^n}$ is divergent, because its term doesn't approach zero. $\sum\limits_{n=0}^{\infty} \dfrac{(-1)^nn!e^n}{n^n}$ is also divergent, because, although the absolute value of the ratio between two successive terms, $|e|\left(\frac{n}{n+1}\right)^n$, approaches 1 as $n\to\infty$, it approaches 1 from values bigger than 1; therefore, the absolute value of a term is always greater than the absolute value of the previous term.


I'm using Raspberry Pi Camera v1 with the following parameters  Sensor size: 3.67 x 2.74 mm (1/4" format) Pixel Count: 2592 x 1944 Pixel Size: 1.4 x 1.4 um Lens: f=3.6 mm, f/2.9 Angle of View: 54 x 41 degrees Field of View: 2.0 x 1.33 m at 2 m Full-frame SLR lens equivalent: 35 mm Fixed Focus: 1 m to infinity   The default image dimensions is 1920 x 1080 px. How to determine the image dimensions in metric units based on the given parameters?

What size images do I need for common print sizes, such as wallet size, 8x10, and 16x20?  Is there a general formula?  How could that size change if, for example, a 16x20 was printed on canvas rather than photopaper?


And does that tell us anything about the properties of matrix A?

I have performed Gaussian elimination on this matrix to reduce it to   $$ \left[ \begin{array}{@{}ccc|c@{}} -3&-1&2 & 1 \\ 0& \frac{-5}{3}& \frac{10}{3} & \frac{8}{3} \\ 0&0& a+2 & b + \frac{6}{5} \\ \end{array} \right] $$  I thought that setting $a$ equal to $-2$ and having $b$ not equal to $-\frac{6}{5}$ would be the answer to this problem, but it apparently isn't. Could someone please explain why?


edit : I have added the relevant EXIF data, Still exploring how to add the EXIF data inline with the photos, please excuse english is not my first language  I am a newbie photographer with Nikon D3300 and the kit lens + 35mm 1.8. Previously I used to have a Sony Nex 5r with 16-50 lens. I "Upgraded" to a D3300 because I wanted cheaper lens, more accessories but also more detail that I thought will come with the increased resolution.  Unfortunately most of my pictures, especially flower pictures lack detail. I am not talking about "Macro" level detail. But textures which were visible previously on the nex5r are no longer visible with the Nikon.  I have already tried the following:   Tried stopping down. Used both kit lens and 35 mm. Tried fill in flash. Tried under/over exposing. Tried changing White balance / Picture control. Tried manual focus.   It seems like either the lens or the sensor are just not resolving enough detail.  I generally shoot in single point Auto Focus mode using the centre point and placing it on my target.  Picture control is set to " Standard" with saturation "+1" and Sharpness "+3" Several members have commented that the first photo is Out of focus. Well the target focus was the white flower, and I took several samples to rule out camera blur. Also Even when taken using manual focus and using In camera Viewfinder focus Indicator, correct focus was indicated by the camera but still the flower does not appear to be in sharp focus in any of the pics.  As I generally use the viewfinder, I may infer that phase detection AF is not as precise as contrast base detection often used by competing non mirror cameras.  Examples:  1st pic : d3300 +18-55 kt lens at 46 mm,Av priority, f/5, 1/125, ISO 100, Centre weighted  2nd pic : d3300 + 18 - 55 kt lens at 52 mm,Manual exp ,  f/5.6, 1/250 , ISo 100 Centre weighted  3rd pic : d3300 + 35 1.8 G DX , Manual Exp ,   f/5, 1/400 , ISO 100 , Centre weighted  4th pic : d3300 + 35 mm 1.8 dx, Av priority, f/5.6, 1/160 , ISO 100, Centre weighted       I know it may be just paranoia , but if it is a lens or a misfocus issue then I must contact Nikon. Please advise.  While It might be true, That the photos may be post processed to look better, Is there some setting I can change to get a decent Jpeg output from the camera itself? To put it bluntly I would like a jpeg as thrown out by mirrorless cameras from Sony?  also I have tried showing the focus point in the first photo (the blurred one) by using a screen shot from the view nx2 software from Nikon:

I use a Canon EOS Rebel T3i (600D) with the kit lens. I have experimented a lot with different settings and modes, but I feel like I have wasted many good shots that could have looked amazing, if only they were a little bit sharper.  I use auto-focus on most of my pictures and make sure to choose the right focus point, but all of my photos are still a little bit out of focus. When I zoom in, I can see that the pixels are not very crisp or well-aligned.  I am not sure if this issue is caused by my equipment or skills.


We are using SQL Server 2016 Enterprise Ed with AlwaysOn Availability Group.  If we want to encrypt our database backups, how do we go about creating the encyrption keys?  For example, do I create the same Certificate used on both primary and secondary?  I am thinking it would be the same cert since the backups could be happening on any of the two replicas.  Anyone have any guidance on this?  I am new to encryption so this is all new to me.  Thanks for any help!

When we implement the Always Encrypted feature in SQL Server 2016, do the .mdf files, .ldf files and .bak files get encrypted as well?  I would like to know if the data/log/backup files gets encrypted or not.


Explore convergence of the series $$\sum_{k=1}^{\infty} \left( \frac{1+\cos k}{2+\cos k}\right)^{2k}$$    Using root test: $\sqrt[k]{a_k} = \left( \frac{1+\cos k}{2+\cos k}\right)^2$ $$\lim_{k \rightarrow \infty} \left( \frac{1+\cos k}{2+\cos k}\right)^2 = \lim_{k \rightarrow \infty} \left(1- \frac{1}{2+\cos k}\right)^2$$  Now as I understand this limit is not really defined but we know it is between $0$ and $\frac{4}{9}$ and therefore is less than $1$. So by root test the series converges. But is this solution correct?

I need to find out whether the following series converges or diverges. If it converges I also have to discover whether it is an absolute convergence or a conditional one. $$\sum_{k=1}^{\infty}\left(\frac{1+\cos k}{2+\cos k}\right)^{2k}$$ Root test did not help me much since $\lim_{k\rightarrow\infty}\left(\frac{1+\cos k}{2+\cos k}\right)^2$ may equal anything from $0$ to $4$. Comparison tests also did not work well. I guess this series is convergent, though. But I still have no idea how to prove it.


I have a Canon Eos 650D. I want to buy a macro lens, both for macro and portrait.  Everybody tells me the Canon 100mm is better then Tamron. But Tamron has VC. Which lens is better? Which one do you prefer?

I have a Canon 40D and like taking macro shots sometimes, so I'm thinking of buying a macro lens. I'd also like the lens to double up as a portrait lens. I'm not a super serious photographer, so my budget is not huge, but I'm considering the Canon EF-S 60mm f2.8 USM Macro Lens and the Canon EF 100mm f2.8 USM Macro Lens. I also note that Sigma and Tamron have lenses in that focal range and price range.  So reasons I can think of to go for the 60mm would be:   smaller and lighter probably a better focal length for portraits bit cheaper   While the 100mm would be better for:   insect photography, as I could keep my distance a little better.   Are there other key factors to consider? Would you recommend one of the third party lenses as particularly good? Are there any of these lenses to avoid?


Sometimes I see beginners in a subject (it is apparent in the question) asking for solving some issue. My natural instinct is to guide them to resolving the problem themselves rather that just giving the answer. I think it is better education to learn how to solve the problem in general than get a quick answer.  However I do not think this is really correct for Stack Exchange. What is the best way to proceed for such examples?

I got this odd comment to one of my answer earlier today:     How about showing how this would be applied to OP's question.   My answer (deleted since) was:     Try to split the string and use a range type to build the array: (1..10).to_a   The question was about building a list of IPs given two end points:    Speaking personally, I'd rate my own answer as good enough, since it would have been more than enough to get me googling in the right direction. Admittedly, a better answer eventually creeped in -- it would have gotten my vote and acceptance.  Question for meta, though: is this type of answer (which can occasionally be long) valid, or not? More examples of the same type of hint-only answer:      My issue with getting comments that amount to "show working code" is that it reduces StackOverflow to a crowd-sourcing site. IMO, OP should get the same type of answer as he'd get from a busy colleague, e.g "try this direction, should yield something" rather than a deliverable.


You roll six independent fair dice.  What is the probability that their sum is divisible by 6?  I don't really know where to start. Does the ordering of the dice matter? (1,2,2,2,2,3) vs (3,2,2,2,2,1). I feel like it does. I'm not strong with counting arguments so I don't know how to find the number of ways that you can arrange that.

So the question is really hard I think. I tried using a simple way by calculating the probability of each combination that makes a sum divisible by six, but it would take forever. Does anyone have any ideas?  Suppose that we roll a six-sided die ten times. What is the probability that the total of all ten rolls is divisible by six?


When I was trying to install Kali 2020 from the live ISO, I selected the Graphical install, so I end up with the grub install problem. Start again and switch to the text base install and all goes well with zero issues. I ran into this twice, there is something about the graphical installation that causes the problem, install using text based installation, not as pretty but works good.

I am installing kali linux on my pc. while installing install the grub boot loader on a hard disk.  I am trying to install kali linux with grub as your bootloader and that step is failing.   Error: GRUB installation failed. The 'grub-pc' package failed to install into /target/. Without the GRUB boot loader, the installed system will not boot.     I used bootable pendrive.   An error message like grub installation failed . what should I do ?  I am made a rufus usb insatller with kali linux . then Install manually, after install the system then I'm stuck in installing the grub boot load  Grub installation failed the grub-pc package failed to install into /target without the GRUB boot loader this installed system will not boot   Then I select execute a shell,  mount --bind /dev /target/dev mount --bind /dev/pts /target/dev/pts mount --bind /proc /target/proc mount --bind /sys /target/sys chroot /target /bin/bash root@kali:/# apt-get install grub-pc reading package list done building package list done building dependency tree reading state information done packege grub-pc is not available ,but is reffered to by anther package this may mean that the package is missing, has been obsoloted or is only available from another source


I started a couple months ago to learn more about the stock market and financial education in general, but this particular concept was hard to wrap my head around.  I understand there are bears and bulls behaviors in the stock market, but when I go and sell a stock, how can I sell it if I don't own any of that stock already?  I can understand if I go around the block, find someone selling shoes for 10$, I buy them, then I go two blocks down the street and find someone wanting shoes for 12$, I can make a profit by Selling to him.  But if I reach the guy that wants shoes, how can I "Sell" something I don't own yet?

I'm trying to wrap my head around short selling. Online the explanations i found talk about borrowing a stock from your broker, selling it at a high price then waiting for the stock to drop in price and buying it back for that low price, so you can return the stock to its original owners and pocket the difference, this i get. my question is, how can you sell something that you borrowed, how can you sell something that is not yours. like for example if i borrowed my friends car, i can't sell it because i wouldn't have the pink slip, so how can i sell stocks that i don't own? Thanks in advance.


I have two machines, and I have installed the exact same packages on both machines.  On one machine everything is working perfectly fine. But on another machine, there is at least one file where its No such file or directory, even if it is present and executable.  I can read the contents of file also.  I know that file is of 32bit, but on another machine same 32bit binaries are working okay.  Can somebody please help.  1st machine : Working Fine  bash # file /sbin/vxdmpadm /sbin/vxdmpadm: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 3.0.0, BuildID[sha1]=f62ed2d5a57fb9893ad2a89083c66493ce547c10, not stripped  bash # uname -a Linux 3.12.28-4-default #1 SMP Thu Sep 25 17:02:34 UTC 2014 (9879bd4) x86_64 x86_64 x86_64 GNU/Linux  bash # /sbin/vxdmpadm VxVM vxdmpadm ERROR V-5-1-2110  Incorrect Usage # << Expected.  bash # ls -lrt /sbin/vxdmpadm -r-xr-xr-x 1 root sys 972953 Oct 14 19:08 /sbin/vxdmpadm   2nd Machine - Faulty One  bash # file /sbin/vxdmpadm /sbin/vxdmpadm: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 3.0.0, BuildID[sha1]=2d90bb5228e59b2e8de22d0b8db36fb85aeb1064, not stripped  bash # uname -a Linux  3.12.28-4-default #1 SMP Thu Sep 25 17:02:34 UTC 2014 (9879bd4) x86_64 x86_64 x86_64 GNU/Linux  bash # /sbin/vxdmpadm bash: /sbin/vxdmpadm: No such file or directory   # << Why this is coming  bash # ls -lrt /sbin/vxdmpadm -r-xr-xr-x 1 root sys 972953 Aug 31 08:40 /sbin/vxdmpadm

I have currently a strange problem on debian (wheezy/amd64).  I have created a chroot to install a server (i can't give any more detail about it, sorry). Let's call its path /chr_path/. To make things easy, I have initialized this chroot with a debootstrap (also wheezy/amd64).  All seemed to work well inside the chroot but when I started the installer script of my server I got : zsh: Not found /some_path/perl (the installer includes a perl binary for some reasons)  Naturally, I checked the /some_path/ location and I found the "perl" binary. file in chroot environment returns :  /some_path/perl ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.2.5, not stripped   The file exists, seems ok, has correct rights. I can use file, ls, vim on it but as soon as I try to execute it - ./perl for example - I get : zsh: Not found ./perl.  This situation is quite understandable for me. Moreover :   I can execute other basic binaries (/bin/ls,...) in the chroot without getting errors I have the same problems for other binaries that came with the project When I try to execute the binary from the main root (/chr_path/some_path/perl), it works. I have tried to put one of the binaries with a copy of my ls. I checked that the access rights were the same but this didn't change anything (one was working, and the other wasn't)


I'm trying to install Ubuntu and in BIOS there is no boot from USB drive or anything like that. I would boot it from disk, but my laptops CD/DVD reader is broken and it can't read anything. Please help?

I tried to use the usb-creator.exe from Ubuntu 10.10 desktop i386 ISO image and it does create an USB stick that doesn't boot. When I try to boot from it I get:     Operating System not found.   I try to do this from Windows 7 x64. I'm not looking to create a live Ubuntu media, only an installation USB disk.  I repeated the process several times and I even tried to reformat the USB drive (FAT32), no success yet.  The USB stick is a 8GB one.


Let $f:D \rightarrow D$ be a holomorphic function such that f has a zero of order $N\geq 1$ at the origin, then show that $|f(z)|\leq |z|^N$ $\forall z\in D$, where $D=\{z\in\mathbb{C}| |z|<1\}$  I tried to use Schwarz's lemma inductively here. I showed that $f^n(D)\subseteq D$, but then I don't know how to approach it

Prove if $f : D(0,1) \rightarrow \overline{D}(0,1)$ is an holomorphic function in $D(0,1)$ and $f$ has in $z=0$ a zero of order $n$. Then,    $$|f(z)| \leq |z|^n$$   for all $z\in D(0,1)$.   $\textbf{My attempt}$. If $f$ has a zero of orden $n$, then   $$f(0)=f'(0)=\ldots = f^{n-1)}(0)=0 \text{ and } f^{n)}(0)\neq 0$$.  Then, applying the Schwarz's Lemma I get that  $$|f(z)|\leq |z| \; , \; |f'(z)|\leq |z| \text{ and } |f^{n-1)}(z)|\leq |z| $$.  I don't know what to do now to get $|f(z)| \leq |z|^n$.


Will it save car from force of front collision with a fast moving vehicle if I put my car in neutral? I am assuming force will only set off stationery vehicle into kinetic motion.

I was waiting on a red light the other day and was wondering.    If I'm in my car, not moving and I see a car that's going to hit me from behind. Would I (my body) be safer if I put on the break or if I put the car in neutral?  I assume there's no car in front of me and there's no posibility to be hit by an other car. Also, the car crashing into me is going at a good speed.


I have an odd list, interrupted by normal text introducing its last item:  \documentclass{memoir} \usepackage{enumitem} \usepackage{lipsum} \begin{document} \lipsum[1] \begin{enumerate}[itemsep=-4pt] \item My first item \item My second item\\ Along with these should be mentioned: \item My third item \end{enumerate} \end{document}   The text between item two and three, "Along with these...", is supposed to break out of the list and start at the left edge of the textblock. How do I push it to the left, if that's at all possible?  I already tried the following between item 2 and 3,   \end{enumerate} \vspace{-2\baselineskip} Along with these should be mentioned: \vspace{-\baselineskip} \begin{enumerate}[itemsep=-4pt] \setcounter{enumi}{2}   but the inter line space was somewhat off.

I'd like to be able to resume an enumerated list, continuing the old numbering, after some intervening text which should not be formatted like a list item.  Is there a nice way to do this?    In particular, I don't want to start a second list with a hard-coded initial counter value, because that will break if I change the number of items in the first list.


I've asked this question as a guest   Now, I think I had account on stackoverflow with the SAME EMAIL ADDRESS When I tried to login with that email I just get this new account I'm writing from now and can't add comments to my question. So, What can I do ?

I accidentally posted a question without being logged in. Is there a way to associate that question with my account?   For more information, visit "" in the .   a.k.a. How can you link a registered account to a cookie-based account? a.k.a. How do I merge an unregistered account with a registered account a.k.a. Merging users a.k.a. How do I associate anonymous questions I’ve asked with my registered account? a.k.a. Is there a way to claim an unregistered user? (in case anyone searches with those terms)


I'm curious and I want to know all different methods for getting the IP address from a Linux box, I know ifconfig works well, but wondering if there are any other methods to use to obtain the ip address?

I'm using Linux CentOS 6.4 .  I'm writing a shell script and I need to extract a machine's IP in order to use it in the script. How can I find the machine's IP?  I'm looking for the "best" way because I know there are a few ways to get IP addresses.  Thanks


Express $\forall n \in \mathbb N$, $\exists m \in \mathbb N$, $n^4 = m^2$ in words without using the symbol $\mathbb N$.   My Solution:  For all $n$ that is an element of Natural number there is $m$ that is also an element of natural number such that $n^4 = m^2.$  Can I have a feed back on my solution or explanation on how to do the problem.

Express  $$\forall\ n\in\mathbb N\ \exists\ m \in\mathbb N: \ n^4 = m^2$$  in words without using the symbol $\mathbb N$.


From a dictionary and  a usage guide, I learnt that these phrases are OK:  the home of a schoolteacher the sister of the Duke of Urbino a friend of my mother's a cousin of Lorna Cook's a close friend of the President's  The usage guide says that sometimes the 's can be omitted, especially in AmE. So my first question is 1. Are the first two phrases from their 's versions, i.e.  the home of a schoolteacher's the sister of the Duke of Urbino's  ? 2. If so, then why do  a cousin of Lorna Cook a friend of my mother  whose 's are omitted seem to be uncommon ? Or they aren't? Is there any rule, pattern or tendency to which I could stick regarding this issue?

The king underwrote the journey of Spain's prince.  The king underwrote the journey of Spain's prince's.    We have a double possessive here, we are referring to the journey of the prince of Spain. How do we express that in a sentence? If I were refer, say, to a house that belongs to may uncle I would say "the house of my uncle's". For this reason I think the second sentence is correct but it sounds a bit odd. Can you help me?


"Quorum" and "Convention" participation badges are listed on non-meta sites but not on the meta sites, sensibly (they are for participation on meta).  "Precognitive" and "beta" should also be not shown on the meta site badge lists, if they are not awarded.  I would also suggest hiding these badges on pre-Area 51 sites where they do not apply (e.g. Precognitive on StackOverflow).  Discussion on that proposal, however, can be found  (thanks, Oded).

Per-site metas lists some badges that are impossible to get. For example  lists:         But these are impossibly to get because per-site metas do not support bounties, were not in a beta stage or Area 51 proposals. I therefore suggest that these badges are removed from the per-site metas. They have no function and they are confusing. There are already badges that are unavailable on per-site metas but available on the main sites:    Convention Quorum  This seems to suggest that per-site metas should only contain badges that can be possibly awarded.


There's this children's fantasy series I've been trying to find for years from one book I've read in my youth. From what I recall it was a long-ish series (7-8 books?) and I believe that the powers in the books were based on gems, or some kind of stones. I read this series about 8-7 years ago and it was finished by then - hopefully that gives a rough time period for people to pin it too.   I know the one book I read was either the last or near last book in the series, and the only part of the plot I can vividly remember were incredibly large sea monsters arriving from the ocean/sea to attack some sort of...tower? I believe there were also illustrations of these monsters (though I'm not sure if I'm not just mistaking those illustrations for my imagination).  I think I also recall a segment about a character trying to escape some sort of mine, where there were Underseers/Overseers, though that may not have been in this same book (I don't remember if I only read one or two books of the series, haha). I also remember there being some sort of love story if that's any help (probably not).  Sorry this is so vague, and I hope someone can give me an answer eventually! It's been really bugging me, and I can't seem to find any series like it anywhere.

I've been trying to find this darn series of books for ages, I read them back in early 2001-02 and can't really remember much of them. I think there were 10-ish books, it was an easy read but a long series. On early publications, the covers, were mainly yellow, with small pictures of whatever happens in that book.  The book began with two siblings, a brother and a sister, running in a forest. She conjures up what can only be remembered as a golem type creature. He then uses a high magic 'blast' and wipes out the golem, knackering himself. His sister laughs at him for being 'powerful' but expending himself too much on one big magic blast. The beginning I remember vividly, the rest, not so much.  The story continues as a conflict happens, I believe two worlds are involved? The brother and sister are split up, but this is where my memory becomes vague.  The mechanics of the world seems that there are gems, or stones, set in the backbone, which in turn give access to magic. When the person uses them, they can draw too much, which ends up exhausting them. The 'big bad evil king' kills their father, and destroys their farm early on in the story.


Consider a planet of mass $m$ moving around the Sun of mass $M$ in a circular orbit of radius $r$. By equating the centripetal force to $\frac{mv^2}{r}$ to gravitational attraction $\frac{GMm}{r^2}$, one finds $v=\sqrt{\frac{GM}{r}}$ where $v$ is the planet's tangential velocity.   How does one calculate the tangential velocity if the planet's actual orbit (which is elliptical) is taken into account?

Consider some some satellite of mass $m$ around earth, traveling in an elliptical orbit about a focus (earth). Let's suppose at one point $A$ the satellite is a distance $a$ units away the focus at minimum distance, and at another point $B$  it is at a distance of $b$ from the focus, a maximum distance. Let points $A$ and $B$ be collinear with the center of the Earth. When the satellite is at a distance of $a$, it's speed is equal to $v_0$.    Calculate the speed of at the satellite a distance $b$ from the focus.  So first I approached this by the conversion of mechanical energy:  $$\frac{1}{2}mv_0^2-\frac{Gm_e m}{a}=\frac{1}{2}m v_b^2-\frac{G m_e m}{b}$$  I got,  $$v_b=\sqrt{v_0^2+2Gm_e(\frac{1}{b}-\frac{1}{a})}$$  But then I realized conservation of angular momentum gives,  $$mv_bb=mv_0 a$$  $$v_b=\frac{a}{b}v_0$$     I don't see how the two can be equivalent. Is one answer wrong? May someone please explain.


What is the file system for external hard disk that supports access from Windows and Mac OS X? Also, I would like to backup using Mac Time Machine application, and use the disk to store other data.  I'm currently using Seagata Backup Plus Portable as the external hard disk. Windows OS: Windows 10 Mac OS: OS X El Capitan

I have an external storage device that's pretty big. I would like to store my OS X Time Machine backup files on it, but it already has a few files I've backed up from a windows machine. Will it be a problem to do both (File System wise), or should the time-machine work without problems? I don't want to lose any files already stored on the device. thanks.


What is the next number in the sequence ?  1 1 1 2 1 1 2 1 1 1 1 1 2 2 1 3 1 2 2 1 1 1 3 1 1 2 2 1

I have this pattern:  1 11 21 1211 111221   I'm guessing it's a fibo pattern, been at it for hours now. Anyone know?


I need a horizontal line to span across the page, up to the right margin (where the text would end). This works:  \rule{\hsize}{0.4pt}   But, when inside a list, the line goes over the margin because it is indented, and \hsize of course doesn't check for indentation.  How can I make the line's length account for the list's indentation?  Example:  \documentclass{article} \begin{document} \section{Some section}  \begin{enumerate}     \item Some text \\ \rule{\hsize}{0.4pt} \end{enumerate} \end{document}   Output:   As you can see, the line goes over the right margin. (compare to left and top margins)

The three lengths \textwidth, \linewidth and \hsize seem to all hold the width of the current line. At least I never saw some real difference between \textwidth and \linewidth in my code. Both seem to be identical even when changed, e.g. by a minipage environment.  Could someone give me an elaborate explanation of the differences between these lengths? I like to understand them in detail. I know that the first two are from LaTeX and the latter one from plainTeX.  There is also \columnwidth which seems to be identical to \linewidth or \textwidth in one-column mode, right? Except when the line is reduced by a minipage or quote etc. environment.


Although elements like
s normally grow to fit their contents, using the float property can cause a startling problem for CSS newbies: If floated elements have non-floated parent elements, the parent will collapse. For example:

Div 1

Div 2

    The parent div in this example will not expand to contain its floated children - it will appear to have height: 0. How do you solve this problem? I would like to create an exhaustive list of solutions here. If you're aware of cross-browser compatibility issues, please point them out. Solution 1 Float the parent.

Div 1

Div 2

    Pros: Semantic code. Cons: You may not always want the parent floated. Even if you do, do you float the parents' parent, and so on? Must you float every ancestor element? Solution 2 Give the parent an explicit height.

Div 1

Div 2

    Pros: Semantic code. Cons: Not flexible - if the content changes or the browser is resized, the layout will break. Solution 3 Append a "spacer" element inside the parent element, like this:

Div 1

Div 2

    Pros: Straightforward to code. Cons: Not semantic; the spacer div exists only as a layout hack. Solution 4 Set parent to overflow: auto.

Div 1

Div 2

    Pros: Doesn't require extra div. Cons: Seems like a hack - that's not the overflow property's stated purpose. Comments? Other suggestions?

I have the age-old problem of a div wrapping a two-column layout. My sidebar is floated, so my container div fails to wrap the content and sidebar.

   There seem to be numerous methods of fixing the clear bug in Firefox:
 overflow:auto overflow:hidden   In my situation, the only one that seems to work correctly is the
 solution, which is a little bit scruffy. overflow:auto gives me nasty scrollbars, and overflow:hidden must surely have side effects. Also, IE7 apparently shouldn't suffer from this problem due to its incorrect behaviour, but in my situation it's suffering the same as Firefox.  Which method currently available to us is the most robust?


Is there a standard for where each SE site should link to its required reputation for privileges? I was searching for that for a particular SE, and only found it by doing a web search for privileges stack exchange and finding Stack Overflow's, then guessing that the URL structure would be consistent.  That's a pretty weird user experience. Is there a better way to find it?

Am I so myopic as to not see the obvious link somewhere? I came looking for it immediately after seeing King Atwood's post but couldn't find it.  It seems appropriate to just put the list on the "reputation" tab of user profile, or at least a prominent link.


I want to print out handout for my beamer presentation. I am trying to get pgfpages package from MiKTeX package Manager without success? Can you please help?

I'm new to LaTeX, investigating using it for some work projects.  I'm using MiKTeX on Windows.  My employer's locked-down network blocks the application's automatic installation function.  I can take my laptop home and successfully install from there, but if I need a package in the middle of the day I'm stuck.  I am able to access the CTAN website and download the package files (.dtx or .ins?), but I don't know what do do with them.  How can I do a manual package installation?


I have a very peculiar problem, following an answer in  I am trying to rename some files. This is the code I am using #!/bin/bash for file in *.HHZ_00; do mv $file ${file/${file:14:2}/00}; done  What I understand this to do is to replace the 2 characters following character index 14 (starting from zero) to 00. I am using 2 subsets of files to test it, one is this 2018113154211.25.AGCC.HHZ_00 2018113154211.25.APAC.HHZ_00  When running the code these successfully rename to 2018113154211.00.AGCC.HHZ_00 2018113154211.00.APAC.HHZ_00  The second subset fails at this, this subset is 2018070220829.28.AGCC.HHZ_00 2018070220829.29.APAC.HHZ_00  These rename unsuccessfully to 2018070220829.00.AGCC.HHZ_00 2018070220800.29.APAC.HHZ_00  Notice how the indices 11 and 12 are changed for the second file, not the 14 and 15 as I want it to, very curiously now the SECOND time I run it, using the last files as input, I get 2018070220829.00.AGCC.HHZ_00 2018070220800.00.APAC.HHZ_00  This is partially successful, but now the second filename is ruined...what am I doing wrong? Is it because the 29 is repeating in these files? If someone has a solution using the rename command that would be great too, I tried using it but I am unfamiliar with the syntax.

Under following conditions-   mv within the same HDD partition mv to a different partition in the same HDD mv to a different device (e.g. USB HDD)   Is the complete file moved or is it a very small change like some pointer reassignment ?


If $k\le d$, then $M\subseteq\mathbb R^d$ is a $k$-dimensional $C^\alpha$-submanifold iff for all $p\in M$, there is an open neighborhood $U\subseteq\mathbb R^d$ and a $f\in C^1(U,\mathbb R^{d-k}$ with $M\cap U=\{f=0\}$ and such that ${\rm D}f(x)$ has full rank for all $x\in U$. Now there is an equivalent definition which states that $M$ is a $k$-dimensional $C^\alpha$-submanifold iff for all $p\in M$, there is an open neighborhood $U\subseteq\mathbb R^d$ and a $C^\alpha$-diffeomorphism $F:U\to F(U)$ with $F(M\cap U)=V\cap(\mathbb R^k\times\{0\})$. Now consider, for example, the unit sphere $M:=S_{d-1}=\{x\in\mathbb R^d:|x|=1\}$. Considering $$f(x):=|x|^2-1\;\;\;\text{for }x\in\mathbb R^d,$$ it's easy to see that $M$ is a $(d-1)$-dimensional $C^\infty$-submanifold and $f$ is as in the first definition.  How does the corresponding diffeomorphism from the second definition look like?

Example $5.9$ on page $103$ of John Lee's Smooth Manifolds says the following:  The intersection of $S^n$ with the open subset $\{x:x^i>0\}$ is the graph of the smooth function $$ x^i=f(x^1,\dots,x^{i-1},x^{i+1},\dots,x^{n+1}) $$ where $f\colon B^n\to\mathbb{R}$ is $f(u)=\sqrt{1-|u|^2}$. The intersection of $S^n$ with $\{x:x^i<0\}$ is the graph of $-f$. Since every point in $S^n$ is in one of these sets, $S^n$ satisfies the local $n$-slice condition, this is an embedded submanifold.  The terminology is that if $M$ is a smooth manifold, and $S\subset M$ a subset, then $S$ satisfies the local $k$-slice condition if each point of $S$ is contained in the domain of a smooth chart $(U,\varphi)$ for $M$ such that $S\cap U$ is a single $k$-slice in $U$.   I don't see how this makes $S^n$ satisfy the local $n$-slice condition. Presumably the chart on $\mathbb{R}^{m+1}$ is $(U=\{x:x^i>0\},\mathrm{id})$, so that $S^n\cap\{x:x^i>0\}$ is an $n$-slice of $U$? But this doesn't seem right since $\mathrm{id}(S^n\cap U)$ is a hemisphere of $S^n$, but that's not a $n$-slice in the corresponding half-place $\mathrm{id}(U)$?


I have over 7,000 pictures on my iPod Camera Roll. I recently signed up with iCloud but only the pictures I take after signing up with iCloud go to my Photo Stream. How do I get the first 7,000 pictures onto my Photo Stream?  I want all of my photos to be available on any iOS device where I sign in with my iCloud account.

Not all of my photos go to Photo Stream, some still go to my Camera Roll.  I'm trying to get them on my Photo Stream so they will be on iCloud. With 30 photos on my camera, 10 in stream, I took 6 photos.  2 appeared in stream, 4 did not.  Some of my subsequent photos also appeared in the stream, but not all.  This is arbitrary behavior by the program.  How to fix?  Assume ios 7.0.


Possible Duplicate:          How to prove $$\arctan(1)+\arctan(2)+ \arctan(3)=\pi$$


I'm stuck on the following problem.  I have a start range date and end range date calculated by a query and I have three columns also produced by another query, the outcome of the last query is:  PRJ_ID | START_DATE | END_DATE   I want to produce an output using a stored procedure that considering all the months between start range date and end range date produces an output like this:  PRJ_ID | MONTHS1-YEAR | MONTHS2-YEAR | ... | MONTHSN-YEAR XXXX   | YES     | YES     | ... | NO   The yes or no is obtained checking if the current month is in between the start_date and end_date of the project (table obtained above).  I'm able to produce all the months between two dates with this code:  DECLARE @StartDate  DATETIME,         @EndDate    DATETIME;  SELECT   @StartDate = '20110501'                 ,@EndDate   = '20110801';  SELECT       DATENAME(MONTH, DATEADD(MONTH, x.number, @StartDate)) AS MonthName FROM         master.dbo.spt_values x WHERE        x.type = 'P'             AND x.number <= DATEDIFF(MONTH, @StartDate, @EndDate);   But I'm stuck on producing the last result.  Here is my try, but I'm getting an error on @prjdates format that is not datetime:  DECLARE @StartDate  DATETIME,         @EndDate    DATETIME,         @minStart    DATETIME,         @orig_estimated_MaxEnd    DATETIME,         @maxEnd    DATETIME,         @curr_planned_MaxEnd         DATETIME;   SELECT   @StartDate = '20110501'                 ,@EndDate   = '20150801';  SET @minStart = (SELECT MIN(start_date)                  FROM [PPM].[dbo].[prj_details]                  WHERE start_date IS NOT NULL                     AND start_date <> '1900-01-01') ;  SET @orig_estimated_MaxEnd = (SELECT MAX( DATEADD(day,orig_estimated_duration*7, start_date)) As FinishDate                               FROM [PPM].[dbo].[prj_details]                               WHERE start_date IS NOT NULL);  SET @curr_planned_MaxEnd = (SELECT MAX(curr_planned_LF)                             FROM [PPM].[dbo].[status_and_updates]                              WHERE curr_planned_LF IS NOT NULL);  SET @maxEnd = (SELECT                    CASE                        WHEN @orig_estimated_MaxEnd > @curr_planned_MaxEnd                          THEN @orig_estimated_MaxEnd                        ELSE @curr_planned_MaxEnd                     END AS MinValue);                  print @minStart; print @orig_estimated_MaxEnd; print @curr_planned_MaxEnd; print @maxEnd;  DECLARE @prjDates VARCHAR(MAX);  DECLARE @prjDatesTable TABLE (     [prjDate] DATETIME );  DECLARE  @from datetime, @to datetime;  SET @from = '20110501'; SET @to = '20150501';  ;WITH Numbers (Number) AS (     SELECT           row_number() over (order by object_id)     FROM          sys.all_objects) INSERT INTO @prjDatesTable      SELECT          dateadd(month, number, @from) AS months     FROM Numbers     WHERE number <= datediff(month, @from, @to);  SELECT @prjDates = COALESCE(@prjDates + '],[', '') +       (LEFT(CONVERT(VARCHAR, [prjDate], 101),6) + RIGHT(YEAR([prjDate]),2)) FROM @prjDatesTable ORDER BY [prjDate] DESC;  DECLARE @projects TABLE(PRJ_ID varchar(200),  START_DATE DATEtime, END_DATE datetime) INSERT INTO @projects      SELECT p.id,start_date,curr_planned_LF as END_DATE     from [PPM].[dbo].[prj_details]as p     left join [PPM].[dbo].[status_and_updates] as s      on p.id=s.id     where curr_planned_LF is not null      and start_date IS NOT NULL;  --select * from @projects; select * from     @projects pivot (   count(prj_id)   for start_date in  ([' + @prjDates + ']) ) piv;

Let's say I have Table A: BookingsPerPerson  Person_Id    ArrivalDate    DepartureDate 123456       2012-01-01     2012-01-04 213415       2012-01-02     2012-01-07   What I need to achieve with a view is the following:  Person_Id    ArrivalDate    DepartureDate    Jan-01    Jan-02    Jan-03    Jan-04    Jan-05    Jan-06    Jan-07 123456       2012-01-01     2012-01-04       1         1         1         1 213415       2012-01-02     2012-01-07                 1         1         1         1         1         1   The system is for events, so each hotel booking could take anything between 1 to 15 days but no more than that. Any ideas would be very much appreciated.


How can I change only the higher bit of byte in masm32? Assume I have 00101111 byte and want to get 10101111.

How do you set, clear, and toggle a bit?


I want to create some kind of lighting effect for the engines but I quite new to lighting in general. To be honest, I'm used to sticking a single point lamp in.  From the tutorials I've seen, none of them are for cycles and focus on lighting a whole object anyway, not particular faces of it. The engines I want to add the effect to are the 3 on each wing and the 2 in the middle.  I tried following this () previously but none of it is making too much sense.  The first method shown was using volumetric materials. I've never heard of that before while working in Blender but I thought I myswell try it still but the whole method itself was just too complicated. I just didn't understand half of what it said.  With the composition method, I used the same nodes (with same values) as in  yet I didn't notice any change in my render whatsoever. I guess those effects were supposed to effect the picture as a whole? I don't have any experience with either nodes or composition previously before this.

I was wondering how I could create this effect in blender for an animation:      How can I make this bloom effect?


At the moment different paths (by percentual very few people in the world) are taken to arrive (that is, if an arrival exists) at a theory that can quantise the curvature of spacetime. Considering the three basic forces that operate in spacetime I can imagine them to be quantized (and which obviously has been done in the three gauge field theories of those forces) in spacetime, but what is the argument that says that also the curved spacetime itself is subject to quantization?   It is clear that a curved spacetime, wich lets masses (in the absence of the e.m. strong- and weak force) interact without acceleration (in the sense of a force), is very different from the stuff out off which the workings of three real basic forces are made.  The search is on for many years now, but a solution hasn´t emerged. Can this be a sign of a wild goose chase or is the assumption an axiom, in which case there is nothing left to be answered?

The electroweak and strong forces seem to be completely different types of forces to gravity. The latter is geometric while the former are not (as far as I'm aware!). So why should they all be described in the same way? - Why are gravitons needed?  Alternatively, I suppose my question is why a theory of everything has to be some form of quantum gravity. Is there a reason why a theory of everything requires gravity to be quantised? Is it possible for the quantum world and gravity to be described by some overarching theory which does not require gravity to be quantised? Or is there some reason why this is not the case?


I need to make an analysis of this sentence:     ....and we can use them to help you to buy the best product.   or     ....and we can use them to help you buy the best product.   We - subject, can use - verbs, them - indirect subject, to help you buy the best product - direct subject.   Am I right?  I'm not sure if to use to buy or just buy and if it is the part of subject or another sentence.

Source:  by Douglas Crockford (2008) Example:  My goal here is to help you to learn to think in JavaScript. I will show you the components of the language and start you on the process of discovering the ways those components can be put together.  Although it is usually the case that you mostly hear people say something like "this will help you become a better person", is there any particular reason as to why he chose not to leave out the to and say help you to learn instead? If you've got something interesting to say, could you please elaborate on it as well? I would very much like to receive some coherent explanation and get this thing finally straight. The only time I know of, though, that you would use the to is when you say it like this:  It helps a lot to think of the rather difficult concept of classes used in modern software development as mere blueprints that architects and builders use to build houses. In life, it really helps to know your times tables by heart because not all the time do you have a calculator on you.  Because the aspect of the verb "help" is a little bit different here. But in all other cases, help do or help you do something is by far more common.


How do I separate this response in one variable, like I required from below response URL only in one variable? However, "BE050-A28" this value is dynamic in every response.  {   "vehicle": {     "BE050-A28": {       "url": "https://europe.com/iris/iris.jpg?COSY-EU-100-1713d0VXqNSFqtyO35PobzIDneWql9TQw2Mpxikzmxxom7ssM0uBRBbB2Z0iD%25W%25NZWm7ymWdhK0h8f%25v8%257EyLibLlYa4IG2rH"     }   } }  var responsePayload = Platform.Function.ParseJSON(Stringify(response)); var responseUrl = Stringify(responsePayload.vehicle.url); Write("responseUrl : " + responseUrl);

I have an issue which I've been struggling with today. The JSON is returned back to me with a project Id as the key, this Project Id is dynamically generated and due to this I have not been able to come up with a way to deserialize this response. Any suggestions?   {      "success":true,    "numRows":5,    "data":{         "23000079":{            "projectId":"23000079",          "name":"Mcdonalds",          "departmentId":"9383",          "responsibleUserId":"7444434"       }    } }


I was reading "Heart of Darkness", by J. Conrad and I came to this sentence: "A haze rested on the low shores that ran out to sea in vanishing flatness."  My question is: what ran out to sea in vanishing flatness? The haze or the low shores? I don't know if there's any grammatical rule that defines how to recognize the relative clause's antecedent.  Thanks

I'm not sure about the sentence structure below:  All kinds of problems arise that smaller animals or plants do not have to cope with.  It looks like that works as a relative pronoun for all kinds of problems, but I couldn't find such usage in my dictionary or online. This sentence could be divided into  There are all kinds of problems. Smaller animals or plants do not have to cope with all kinds of problems.  But, I can't figure out where 'arise' fits. If you have any thoughts, please share them.


If two strings of equal length from random offsets in Pi were XORed together, would this result in a cryptographically secure random number suitable for use in a one-time pad? If so, would this mean that using a secure low-bandwidth channel, you could bass three digits (two offsets and a length) to provide an arbitrarily long pad?

Let's pretend that all digits of pi are known and arbitrarily long sequences of digits are trivial to get. Further, some mathematician proves that there are no patterns in pi. We could create a stream cipher by grabbing a piece of pi as long as our plaintext and combining the two with some function (such as XOR or modulus addition.) The key would be the starting position in pi.  Would this be equivalent (in terms of security) to a one-time pad? To what sort of attacks would it be vulnerable?


I have 2 domains on my dedicated server running debian.  One of them is linked to a wordpress site, mydomain.com.  I've noticed that on both my sites, lately, the performances were horrible so I started to look for a reason.  I noticed that in the last few days, my daily syslogs were as big as 800mb, filled with notices of deferred emails coming from emails looking like name_surname@mydomain.com, obviously programmaticaly generated.  I updated my wordpress, deleted the deferred queue (all 130 000 deferred mails making it) of postfix, and waited 10mn.  After 10mn, the queue is filled with 4000 mails and counting, and can't locate any fishy script anywhere.  I can't find any information about such an exploit, so I'd like to know what I could do get rid of that spam that is killing my server.  If that can help, it seems that every address sends batches of 20 emails.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


In the Search console of Google webmaster, I am getting "Not found" in URL Errors in an extent having suffix /%EF%BB%BF. I have never created these type of pages or in website these URLs never exist. My site traffic is getting hurt due to the issue. If anyone suggests me how to come out of this issue I will be grateful.

Google Webmaster Tools is reporting a crawl error "404 (Not Found)" for an .html page which has never existed on a web site I developed. The page being reported is "tyuiabmog.html", which doesn't sound like it was named by a human!  Please could someone help me to shed some light on how Google came across this non-existent page and why it is trying to crawl it?


Ubuntu is unable to play DVDs. I used regionset to change the region. libdvdcss (the newest version) is installed. I enabled the option "No DVD menus" in VLC, and it doesn't work.  What should I do?

My machine can't play encrypted DVDs on a fresh install.  How do I add this capability?  Another useful bit of information would be what programs are best for playing DVDs, once I'm able to do so.  See the .  Will I be able to play DVD movies from ?


I have to run a query based on data inside of an array. Locally, I tested with names.  $names = ['my name', 'another name'];  if (!$conn) {     die("Connection failed: " . mysqli_connect_error()); }  $sql = "SELECT * FROM `clients` WHERE `name` IN ('".implode("','",$names)."') ORDER BY id DESC";  $result = $conn->query($sql);  while($row = $result->fetch_assoc()) {     print_r($row); }  $conn->close();   This returns the correct rows based on the names in my $names array, but some people are saying that using the implode function inside the query is dangerous. I'm not sure how else to go about this.

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I'm trying to understand global variables in python. But I don't know why _instance_name doesn't fail if I don't declared as global but when I try to do the same thing with _instance_counter this fail       #Module global declaration     _instance_counter = 0     _instance_name = "Employee module"      class Employe:         _internal_counter = 0          def __init__(self):                  global _instance_counter#If I comment this line fails.                           _instance_counter +=1 #count each instance                   #why if I use _instance_name without global statement doesn't fail             print("\t**Instance of %s #%i has initialized**"%(_instance_name,_instance_counter))          def __del__(self):             print("-The class %s has deleted"%_instance_name)          def count(self):             self._internal_counter+=1             print("count method has %i time(s) called "%self._internal_counter)          def getTotalInstance(self):                              print("\t  %i instance of %s has been created"%(_instance_counter,__name__))       empl = Employe()     empl.count()     empl.count()     empl.count()       empl = Employe()     empl = Employe()     empl = Employe()      empl.getTotalInstance()

The following code works as expected in both Python 2.5 and 3.0:  a, b, c = (1, 2, 3)  print(a, b, c)  def test():     print(a)     print(b)     print(c)    # (A)     #c+=1       # (B) test()   However, when I uncomment line (B), I get an UnboundLocalError: 'c' not assigned at line (A). The values of a and b are printed correctly. This has me completely baffled for two reasons:   Why is there a runtime error thrown at line (A) because of a later statement on line (B)? Why are variables a and b printed as expected, while c raises an error?   The only explanation I can come up with is that a local variable c is created by the assignment c+=1, which takes precedent over the "global" variable c even before the local variable is created. Of course, it doesn't make sense for a variable to "steal" scope before it exists.  Could someone please explain this behavior?


$$\mathrm{div}\ {\bf F} = \lim_{V\to\{0\}}{1\over|V|}\oint_V {{\bf F}\cdot d{\bf a}}$$  Wikipedia says:     In physical terms, the divergence of a three dimensional vector field   is the extent to which the vector field flow behaves like a source or   a sink at a given point. It is a local measure of its   "outgoingness"—the extent to which there is more exiting an   infinitesimal region of space than entering it.   If there is a source, it means net flux is going to be positive. Then it means flux $\oint_V {{\bf F}\cdot d{\bf a}}$ shows us that there is a source there. But why do we have to divide flux by "volume"?  I am asking the intuition behind defining divergence as flux divided by "volume".

Reading  first,   Divergence (div) is “flux density”—the amount of flux entering or leaving a point. Think of it as the rate of flux expansion (positive divergence) or flux contraction (negative divergence). If you measure flux in bananas (and c’mon, who doesn’t?), a positive divergence means your location is a source of bananas. You’ve hit the Donkey Kong jackpot.   Wikipedia has:   In physical terms, the divergence of a three dimensional vector field is the extent to which the vector field flow behaves like a source or a sink at a given point. It is a local measure of its "outgoingness"—the extent to which there is more exiting an infinitesimal region of space than entering it.   What puzzles me is, what's the direction?  Doesn't divergence need a direction too?  For example, say you have this 2d vector field  $$ F(x,y) = (x,y) $$  This field is everywhere "spreading" from the origin:    The divergence is:  $$ \nabla \cdot (x,y) = 2 $$  Ie everywhere positive.  Everywhere is a "source".  At every point, if you draw an infinitesimally small circle, as the Wikipedia definition has, no matter how small it is, that circle will see more "stuff" leaving it than entering it -- ie everywhere is a source.  But that only makes sense if you are talking as measured using a vector from the origin.  But nowhere in the definitions of divergence do I see this last bolded comment mentioned, making me uneasy.  Take a vector field with values in the opposite direction:  $$ F(x,y) = (-x,-y) $$    The divergence everywhere is  $$ \nabla \cdot (-x,-y) = -2 $$  Ie everywhere negative.  Everywhere is a "sink".  Ie the field "slows down" at every point.  If you are talking about every point, and the direction of flow is actually towards the origin.  Then and only then, is the function everywhere "slowing down".  So like, what exactly is the divergence at a point?  Does it really make sense?  Am I right about having to consider the direction as towards the origin in order for the "sources/sinks" idea to make sense?  Where is this stated?


I want to draw lines for dimensions with the command \draw[|<->|]...;. In addition, I have line to some other objects, whose dimensions should be stated. However, the lines from the arrow option |<->| are a bit shifted compared to the perpendicular line at the same coordinates. Is there a way to correct this automatically and not manually, like I did it in the example? Subtracting the half line width is only applicable, if the direction of the arrow is known, and only easy, if it's along the coordinate system.  MWE  \documentclass[convert={density=1000}]{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture} \draw[gray] (0,0) -- (0,0.5); \draw[gray] (1,0) -- (1,0.5); \draw[|<->|] (0,0.125) -- (1,0.125); \draw[|<->|] (0-\pgflinewidth/2,0.375) -- (1cm+\pgflinewidth/2,0.375); \end{tikzpicture} \end{document}   Output    Edit:   uses \pgfarrowsdeclare, which seems to be deprecated, as stated in . I'll try to solve my question with the current command, \pgfdeclarearrow. With it I can simply write  \pgfdeclarearrow{name=dim-dim,   means={>.|[sep=-0.25pt]},}   which is a very short solution and almost does what I want. The only drawback is that it is not possible for me to use \pgflinewidth instead of the manual value -0.25pt. This results in the error Missing \endcsname inserted., if I try to compile the following code:  \documentclass[]{article} \usepackage{tikz} \usetikzlibrary{arrows} %\pgfdeclarearrow{name=dim-dim,   means={>.|[sep=-0.25pt]},} \pgfdeclarearrow{name=dim-dim,   means={>.|[sep=-\pgflinewidth]},} \begin{document} \begin{tikzpicture} \draw[gray] (0,0) -- (0,1); \draw[gray] (1,0) -- (1,1); \draw[dim-dim] (0,0.5) -- (1,0.5); \end{tikzpicture} \end{document}   Is there a way to overcome this error?

Usually, when drawing a path with an arrow tip in TikZ, we want the tip to end precisely at the last point of the path, and this is what TikZ does by default. However, with some specific arrow tips, one may wish to control a little more precisely the position of the arrow tip: for instance you may want the base of the arrow to be positioned at the last point of the past instead of the tip.   Here is an example drawing an interval on the real line:  \documentclass{article} \usepackage{tikz,amssymb} \usetikzlibrary{arrows}  \begin{document} \begin{tikzpicture} \draw (-3,0) -- (3,0) node[anchor=south] {$\mathbb{R}$}; \foreach \x in {-1,0,1} \draw (\x,2pt) -- (\x, -2pt) node[anchor=north] {$\x$}; \draw[thick,blue,[-[] (-1,0) -- (1,0); \end{tikzpicture} \end{document}     Is it possible to make sure that the closing square bracket [ is positioned on the tick corresponding to x=1? Of course, it is possible to adjust it manually but this does not seem to be a satisfactory solution.


Hello there!  Currently, I am studying shell programming and there i just learned symbolic link , hard link, files , directories- related topics. I am trying to understand-     why a directory has two links and when a directory is created - why there are . and .. files in the directory? and how they work?  why . file in a directory is necessary?   Good explanations will be helpful for me.  Thanks  in advance.  Best regards- Nazmul

Whenever you type ls -a into the command prompt, you usually get all of your folders, files, and then you see that the first two entries are . and ..  Just curious, but what is the significance of these two entries?


I need to build a polygon (5x5 km) centered on a coordinate X,Y. I want to use this 5x5 square for an eventual clip.  How should I proceed in ArcMap?

I would like to create a square buffer from a point feature but I do not understand the code that goes into it.   Similar questions have been asked on the forums.esri website but that was over 10 years ago, and it did not work when I tried the code.  How do I create a square buffer from a point feature?


I am given 2 sets.  Set $R = \{a+b\sqrt2: a,b \in \Bbb{Z}\}$ and Set $U = \{\alpha \in R: N(\alpha) = 1\}$ where $N(\alpha) = a^2 - 2b^2$  I am supposed to show that $U$ is a subgroup of $\Bbb{R}^x$ which means the set of units over all real numbers.  I was able to show that $1 \in U$ and set $U$ is closed under multiplication, but I still have to show that every element of $U$ has a multiplicative inverse, and I have no clue how to do so.   If you could let me know, I would greatly appreciate it. Thanks!

1) Show that $(\Bbb Z[\sqrt2]^*, .)$ is infinite.  2) Classify $(\Bbb Z[\sqrt2]^*, .)$, where $\Bbb Z[\sqrt2]^*$ is the group of units of $\Bbb Z[\sqrt2]$  What I have done so far that for $a+b\sqrt2$ its inverse will be $\frac {a-b\sqrt2}{a^2-2b^2}$   Now $\frac {a}{a^2-2b^2} \in \Bbb Z$ &  $\frac {b}{a^2-2b^2} \in \Bbb Z$  What conclusion can be drawn from it about the cardinality of $\Bbb Z[\sqrt2]^*$?  One can post the answer also for the 1st part only.


So far I have logged 24 hours in FF VII and I just finished disc 1. Anyway, keeping that in mind, how long can I expect it to take me to get through disc 2, and then disc 3?

I'm going down my huge backlog of unplayed Steam games and I'm thinking the best way to tackle the list is to go through the shortest games first and then concentrate on the 20+ hour ones. I'm wondering if there's a website or something else that has an estimated amount of gameplay time for games.   Is there anything like that?


I have tries solving by taking log on both the sides, but was unsuccessful. Please upgrade my knowledge.

Given that   $x^x = y$; and  given some value for $y$   is there a way to expressly solve that equation for $x$?


I'm having a hard time understanding how the Magic Initiate feat works;  does it require spell slots? The feat doesn't say the spell cast is free; it only says you can cast it at its lowest level once per long rest. -when you cast it can't cast again - and casting spells normally requires spell slots. The  (PHB, p. 80-81) is an exception because it doesn't say you "can cast" the spell, but rather that you spend ki points "to cast" the spell:  You can spend 5 ki points to cast stoneskin, targeting yourself.  You pay ki instead of spell slots. And  are another exception. For instance, the 's Spirit Seeker and Spirit Walker features (PHB, p. 50) let them cast those spells regardless, because rituals don't expend spell slots but need to pay with 10 min of casting. The description of  says (PHB, p. 201):  When a character casts a spell, he or she expends a slot of that spell’s level or higher, effectively “filling” a slot with the spell  The description of the  feat says (PHB, p. 168):  Choose a class: bard, cleric, druid, sorcerer, warlock, or wizard. You learn two cantrips of your choice from that class’s spell list. In addition, choose one 1st-level spell from that same list. You learn that spell and can cast it at its lowest level. Once you cast it, you must finish a long rest before you can cast it again. Your spellcasting ability for these spells depends on the class you chose: Charisma for bard, sorcerer, or warlock; Wisdom for cleric or druid: or Intelligence for wizard.  Spell slot can cast (PHB, p. 164):  Class Features>Spellcasting>Spell Slots. You can use the spell slots of those levels to cast the spells you do know  if i'm correct you need to know spell,(to prepare, if you need it), to spend slots to cast, so if you Learn you know or can have prepared? considering on the , you can't spend spell slots to cast spells from another class. For instance, the sorcerer errata.  Spell Slots (p. 101). In the first sentence, “your spells” is now “your sorcerer spells.”  but you can cast rituals and spells from your own class, The feat doesn't say the spell cast is free; it only says you can cast it at its lowest level once per long rest. so i can't spend spell slots to cast spells from another class but can chose it, i can cast rituals because dosen't need spend slots and spells from your own class (if they have) because i can spend it slots, but if i choose nonritual spell from another class i can cast it, but can't spend spell slots and if i can't spend spell slots, virtualy i can't cast it, The feat doesn't say the spell cast is free - requires spell slots.; it only says you can cast it at its lowest level once per long rest. - when you cast it can't cast again but this statement seems contradictory, observing the fact exists a ritual caster feat, i think miss something. Does the 1st-level spell you can cast using the Magic Initiate feat need spell slots? Or can you cast it for "free"? What in the text indicates the answer to this question? Please cite only the rules and those rules only of the PHB to support your answer.

Can you cast a spell learned from the Magic Initiate feat using spell slots? Say I play a wizard who learns cure wounds by taking the Magic Initiate feat. Could I cast that spell using the Wizard's spell slots?


I am setting a "formula book" to gather my formulas I need during exams. For that I use a [a5paper, 8pt]{article} but in most cases I use even \footnotesize because it looks better in my eyes and it gives me more space on a small A5 page. extsize does not suit me because the  says its only for 8-20pt.  I was not able to find a definition how to do define that permanently.  Is there any way to set the \normalsize to the size of \footnotesize or define \footnotesize as default?

I'm trying to make a document that has a very small font throughout, I tried this:  \documentclass[0.5mm, a4paper]{article} \documentclass[7pt, a4paper]{article}   But it doesn't seem that they allow me to go anything below 10pt.  This hack make it work, but not for the section headers:  \fontsize{4mm}{5mm}\selectfont   Does anyone know any better ways to do this?


Were the Wheel of Time's  based on Dune's ?   Did Robert Jordan acknowledge or otherwise address this connection?

When I first read Wheel of Time (shortly after I read Dune), I was struck by the  between the Aiel and the Fremen, as well as the White Tower and the Bene Gessirit. Are there any other such similarities? Had Robert Jordan ever accepted whether he was influenced by Dune?


In Javascript, when I want to declare a 'publicly' accessible function what is the idiomatic approach?  MyObj.prototype.foo = function() {     ... }   or   function MyObj() {   this.foo = function() {      ...    } }   What situations would determine one style over the other?  What are the advantages of one over the other?   Thanks a bunch for the help!

What's the difference between  var A = function () {     this.x = function () {         //do something     }; };   and  var A = function () { }; A.prototype.x = function () {     //do something };