I am trying to highlight background for entire section heading using   \documentclass{article} \RequirePackage{titlesec} \RequirePackage{charter} \RequirePackage[hmargin=.3in, vmargin=0.1in]{geometry} \RequirePackage{amsmath} \RequirePackage{textcomp} \RequirePackage{amssymb} \RequirePackage{enumitem} \RequirePackage{xcolor} \RequirePackage{graphicx} \RequirePackage{multicol} \RequirePackage{array} \titleformat{\section}{\large\scshape\raggedright}{}{0em}{\colorbox{gray}}[\titlerule] \titlespacing{\section}{0em}{0.5em}{0.25em} \begin{document} \section{Lobo} (Type your content here.) \end{document}   but it only highlights the text. How do I highlight the entire line ?

I posted this at  and got redirected here. This does indeed look like a better place to ask.  I would like to decorate my headlines (section, subsection, etc.) by adding a background color. I would like this box filled with a single solid color to span across the entire typearea.  This picture is a screenshot of an OpenOffice document where the headline has the formating, layout and color I want.    Requirements on a solution   The resulting style is supposed to be used by others, meaning an equivalent latex output to the picture above shall be created by this code:  Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text   \subsubsection{This is a headline}  Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text Some Text  If the section is supposed to be unnumbered one should be using \subsubsection*. LaTeX still needs to be in charge of the whitespace between paragraphs and the blue box.   What I have tried so far  As far as I can google the headline together with the section numbering are a simple paragraph. Latex adds some skips before and after and squeezes in a few commands that modify the font(s).  My ideas revolve around locking this paragraph in a \colorbox. The colorbox macro works like this: \colorbox{color}{the content around which to draw a box filled with the specified color}. My problem is I can't get a grasp on this paragraph.  The easy 80%  My work is based on koma-script and by redefining \othersectionlevelsformat and \(sub)*section. I can draw two boxes, one surrounding the section numbering and another surrounding the section title. However this has 3 open issues:   the upper edges of the boxes are unaligned and the box with the title is slightly larger than the line with the numbering The box around the title does not strech to the right end of the typearea the box around the numbering doesn't grow if the title spans multiple lines (no surprise here)   The hard 20%  I tried to make latex put the section numbering into a \savebox I could access later and put as part of the title. That would eliminate the need for two boxes and solve all three of my problems at once, but that doesn't work. I only get to modify the title before the actual numbering is done. So while I can put the numbering into a savebox, I can't do anything with it until it's too late.  I tried putting the \section ... statement into a colorbox, but it doesn't like that and the document fails to compile with ! LaTeX Error: Something's wrong--perhaps a missing \item. The same holds for saveboxes. I guess colorbox uses those.  I tried putting the \section ... statement in a minipage and put a box around that. This has two issues. 1st: latex doesn't put any empty space above a section. 2nd: not only the section numbering and title have the background but also the empty space between section title and first paragraph.  So how can one hack latex to do a section title formating as shown in the screenshot above?


There is a major turn of events left unexplained by the Marvel Cinematic Universe.  At the end of first Avengers movie (in 2012) we learned that Thor took the tesseract back to Asgard along Loki (as his prisoner).  Then, suddenly Avengers: Age of Ultron starts with the Hydra guy Baron Strucker sitting on Loki's scepter.   Can someone explain how and when did the scepter switch ownership?

The last time saw Loki's scepter (before it was shown in the post-credits scene of Winter Soldier), all the Avengers were standing around a defeated Loki and Black Widow was holding it.  Is it implied that because HYDRA infiltrated S.H.I.E.L.D., they got hold of Loki's scepter?


It appears that the edit my sites screen has some problems. I am able to add and remove sites, but I can't move them up or down, and only one is visible at a time.      App Version: 1.0.85 Device Manufacturer: motorola Device Model: MotoG3   OS Version: 6.0 (28)

There is some unwanted extra spaces in between each site in the Your Sites section.  Steps to reproduce:   Touch the Nav Icon in the left top corner Touch the EDIT link in YOUR SITES Scroll the screen; there is unwanted spaces in between the each site   For reference I recorded the same:    Configurations:   App Version: 1.0.85 Device Manufacturer: Motorola Device Model: XT1033 OS Version: 5.1 (2)


Is there any way to automatically open a file with the correct program, when using the terminal? Something similar with double clicking a file in GUI.  So for example having a pdf file, not need to write  evince foo.pdf   in order to open it.

When we want to open an application or file from the terminal, we type, say,  okular file.dvi   This opens the application, but also shows the status of the application. We cannot close the terminal, because it kills the process. Unfortunately, if you're trying to, for example, create a LaTeX file, you will need one tab for the text editor, one for the dvi file, and so on. And if you're trying to open all windows from the terminal, you can forget it. I'm trying use the terminal as much as possible, and while I have Yakuake, it is still a bother having so many tabs and seeing which of those have an application I've killed and so on.  So, is there a way to open an application/file from the terminal so that the status doesn't show and immediately gives the prompt so that we can use it to open more applications?


Yesterday I just picked my phone from my pocket and it was prompting me to delete all my messages, and I accidentally tapped the confirm button and lost all my messages.  I don't have any backup and my phone is not rooted. Is possible to recover it?

I deleted an entire SMS thread by mistake from my HTC Wildfire. Is there any way I can retrieve that thread ?


When using the handy search functionality that's spread across all StackExchange sites, keywords in questions are the things that are primarily returned based on your search query. What about adding in an additional functionality to the search that adds in an optional query for usernames as well as questions? If this feature already exists, how is it accessed?

I have a whole bunch of people I would love to follow or at least check out on Stack Overflow. I know them from places like Github as well as personal friends. However I am having a really hard time finding them even though I know e.g. their Gmail address and that they use OpenID via Gmail to login and their full name.   How come this is so painful? Note that I don't want to have to fuzz around with the data explorer just to find a friend of mine on Stack Overflow. What am I missing? Is it just not there or just not working properly?


It shows "unknown command linux16" when I run memtest86+ on efi system.

I'm experiencing frequent "graying out" of my screen in memory-intensive programs like darktable so I'd like to test my RAM (installed 8GB). My Grub menu does not list Memtest as an option however the Ubuntu Software Center reports that Memtest is Installed. How do I run Memtest in this case?  Thanks.  output of grub directory:  -rwxr-xr-x 1 root root  9424 Jun 26 04:16 00_header -rwxr-xr-x 1 root root  6058 May  8  2014 05_debian_theme -rwxr-xr-x 1 root root 11608 May 15  2014 10_linux -rwxr-xr-x 1 root root 10412 May 15  2014 20_linux_xen -rwxr-xr-x 1 root root  1992 Mar 12  2014 20_memtest86+ -rwxr-xr-x 1 root root 11692 May 15  2014 30_os-prober -rwxr-xr-x 1 root root  1416 May 15  2014 30_uefi-firmware -rwxr-xr-x 1 root root   214 May 15  2014 40_custom -rwxr-xr-x 1 root root   216 May 15  2014 41_custom -rw-r--r-- 1 root root   483 May 15  2014 README


I want to know if the inverse of a Triangular matrix (Cholesky decomposition of a symmetric, positive-definite matrix in my particular case) is still triangular. If so could someone provide a proof as well?

How can we prove that the inverse of an upper (lower) triangular matrix is upper (lower) triangular?


given this markup:
     Lorem ipsum dolor sit amet, http://example.com consectetuer adipiscing elit.
   I need a jQuery function, which (after the dom ready event) finds all .myclass divs and transforms the strings which starts with http(s):// into links, so that the above example markup results in this:
     Lorem ipsum dolor sit amet, http://example.com consectetuer adipiscing elit.
   Can you help?  Thanks sub

I am using the function below to match URLs inside a given text and replace them for HTML links. The regular expression is working great, but currently I am only replacing the first match.  How I can replace all the URL? I guess I should be using the exec command, but I did not really figure how to do it.  function replaceURLWithHTMLLinks(text) {     var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/i;     return text.replace(exp,"$1");  }


I am DMing the Curse of Strahd adventure. My players' party is a silver dragonborn fighter, a high elf cleric and a tiefling druid. He brought the fighter to Barovia because he's the last living descendant of Argynvost and he wants to wipe out the bloodline completely, and he brought the cleric because [reasons].  Now I've had an idea for the druid, but I'm not sure if I can make it work. As part of her backstory, she's been travelling the planes trying to find a cure for the curse that befell her homeland (which we've decided is Flotsam from the Dragonlance universe, since it's not out of the question that they'd have some kind of "devil's quarter" there for wayward Tieflings). On one of her journeys she got lost in a demiplane, where she attracted the attention of the Lady of Pain due to her having a pretty unique tail, and the Lady sent an emissary to offer her passage to and a key for Sigil in exchange for half the tail, which she accepted.  Obviously the key won't work in Barovia due to the rules on getting to other planes, which is why Strahd can't leave as well (and the druid tried to use it after realising she'd been transported and it didn't work), but obviously if he could he'd want to in order to escape his endless torment. So I hit upon the idea that the reason he brought the druid to his realm was to offer to restore her ruined wings in exchange for her key (whether he can do this or not or even intends to is a subject for another session) but my question is: is there anything in the 5e RAW that would enable Strahd to make use of a Sigil key to escape Barovia if he had one? I mean DM fiat means I could just say it works, but I'd like to have a way to justify him doing this if that's the way the campaign ends up going (at which point Strahd would escape and start terrorising other planes if they don't go after him).  TL;DR: Could Strahd do anything with a key to Sigil that would allow him to escape Barovia?

As I understand it, by RAI, there's no way out of Ravenloft other than the Dark Powers letting you out, such as via a portal or the mists just transporting you out. I'm wondering if it's possible to get out via RAW without the Dark Powers' permission. Can you Iron Heart Surge the mists, for example? I'm looking for a solution that's within RAW in either 3.5 or Pathfinder, even if it's cheesier than Pun-Pun.


Is $14.9999999$ ad infinitum $\lt 15$, $= 15$, or in between?

I'm told by smart people that $$0.999999999\ldots=1$$ and I believe them, but is there a proof that explains why this is?


I have included libraries amsthm, amsmath, amssymb, mathtools and hyperref and I get an error when I use \left( or \right).  However, it doesn't happen in overleaf, which also includes graphicx, multicol and array.  So, my question is which library contains the \left( command ?

I want to align equations (using the align environment from the amsmath package) inside matching \left( and \right) commands. For example:  \documentclass[a4paper,12pt]{article}  \usepackage{amsmath}  \begin{document}  \begin{align}     a \left( b &= c \right)\\     d \left( e &= f \right) \end{align}  \end{document}   But that code gives this error:     Extra }, or forgotten \right.   The error disappears when I remove the delimiters. Is there a workaround for this?


When I edit some one question/answer then other user see this edit & they have right to approve/reject my edited review.  I also want approve/reject other user edited review. How can do this? Is there mechanism/process to  earn the privilege approve/reject other user question/Answer?

When clicking "edit" I see:  Your edit will be placed in a queue until it is peer reviewed. We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.  Like:     Likewise, when I am not logged in, clicking "improve this question" or "improve this answer" shows:  You are not . Your edit will be placed in a queue until it is .  And when I click 'Save', I get:  Thanks for submitting an edit. It is only visible to you until it's been approved by trusted community members  Like:     Who can suggest an edit? Where do suggested edits go? Who can vote on a suggested edit? How do suggested edits get reviewed? Can I earn reputation? What about abuse or bad edits? Sometimes the Community user approves or rejects my edit. Why is that? When can I not suggest an edit? Is there a minimum change requirement for a suggested edit? How do I check my suggested edit history? I disagree with the reasons why my suggested edit was rejected. What can I do? How do I know whether there are edits waiting for review? Someone suggested an edit to my own post, and the reviewers took the wrong action. What can I do? Are tag wikis included in this scheme? What do the "Improve Edit" and "Reject and Edit" buttons do? Why are apparently valid links to rejected edits resulting in 404 errors?   For more information about editing, see "" in the .


Let $v\in\textbf{R}^3$ have norm one. If $\{v_{1},v_{2},v_{3}\}$ is an orthonormal basis for $\textbf{R}^{3}$ and $v = a_{1}v_{1} + a_{2}v_{2} + a_{3}v_{3}$, can we have $|a_{1}| > 3$? Justify the answer.  I think the answer should be no because they are in $\textbf{R}^3$, is that right?

Question: Let $v \in \mathbb{R}^3$ be a unit vector. If $\{v_1, v_2, v_3\}$ is an orthonormal basis of $\mathbb{R}^3$ and $v = a_1v_1 + a_2v_2 + a_3v_3$, can we have $|a_1| > 3$?  What I think:  Since the norm of $v$ is one, then   $\sqrt{v\cdot v} = 1$  $(a_1v_1)^2 + (a_2v_2)^2 + (a_3v_3)^2 = 1^2$  Since $3^2 = 9 $ and $v_1 \cdot v_1 = 1^2$ (since each vector's norm in an orthonormal basis is 1), then $(a_1v_1) \geq 9$. Since $(a_2v_2)^2 + (a_3v_3)^2 > 0,$ then $(a_1v_1)^2 + (a_2v_2)^2 + (a_3v_3)^2 > 1$. Hence, $|a_1| < 3.$  I'm pretty sure my assumption of $(a_1v_1) \geq 9$ is wrong but I don't know how else to solve this problem.


Something has been bothering me about the Many Worlds Interpretation. Proponents of it (e.g. Sean Carroll) often claim that it does away with the observer, or at least the paradox-inducing status the observer has with Copenhagen. However, my impression is that Many Worlds instead displaces the interpretation of probability, and gives the observer, if anything, a more mysterious role than in Copenhagen. Many Worlds seems to take the probabilism Copenhagen ascribes to the wave function and transposes it onto the observer. In Many Worlds, every possibility of the wave function is realized, so the probability becomes about the observer, and which "world" the observer ends up in. Is this a correct way of thinking about Many Worlds? This doesn't seem to me to do away with the observer, or make its status any less confused than Copenhagen does.

I've been reading about different ideas of getting the observer out of quantum theory. One Sean Carroll seems to like is Everett's many worlds concept.  I had a thought that I need someone here to shoot down. It could be something as basic as the double slit experiment that proves me to be wrong. Here's my thought:  As I see it, we never really "measure" the position of something. We sense a photon that is emitted by what we are "looking" at. Why couldn't the wave function of a particle just break down at the moment it emits the photon at a specific point in space-time regardless of whether there is an observer or not. After the emission, the particle location would go back to being a probability function.  What am I missing?


I've been trying to find rational points on the elliptic curve $y^2=x^3 -x$ but I can't find anything else apart from $(-1,0), (0,0), (1,0)$. I have like an 'edgy' proof that it may not be possible to find rational points on this curve(apart from the ones already mentioned), but I'm unsure about it. Can anyone help?

I believe that the only rational solutions of $$y^2 = x^3 - x$$ are the obvious ones $(-1,0)$, $(0,0)$, $(1,0)$, and that this was proved by Fermat using the method of descent.  Can anyone outline a proof, either Fermat’s proof or a different one; or, failing that, point to a suitable reference, preferably available online?


The spell Creation (PHB, p. 229) states:     You can also use this spell to create mineral objects such as stone, crystal, or metal. The object created must be no larger than a 5-foot cube, and the object must be of a form and material that you have seen before.        The duration depends on the object’s material. [...]       Precious metals — 1 hour   Gold (which could be clearly counted as a "precious metal") has a density of 19.32 g/cm³. A five-foot cube of gold weighs roughly 62 tons.  Note that the spell does not limit whether the material has to be created on the floor or in the air. It doesn't declare any specific physic rules, either, so we can - and have to - assume that the physics apply as if it were normal materials of their respective kind.  If someone were to drop a 62-ton 5-foot-cube on top of you, you would be obliterated. Using a 9th-level spell slot, you could even create a 25-foot cube, if you so desired.  Are there any rules that would indicate how to rule / handle a situation like this?  How can I balance this spell if it can create an object that will instantly kill most creatures below it?

Fall damage is 1d6 per 10 feet. What adjustments if any should I make for objects falling on a player character? (e.g. a bear)  Assuming the objects are meaningful threats but not instant character death, should the weight of an object change the calculation, e.g. more then 1d6 per 10 feet.  Or is this more in the spirit of improvising damage chart? i.e. the setback (cat to face) dangerous (orc fell on me), and deadly (the large bear).  If this is house-rule territory does any one have any experience or advice beyond  relevant to 5e.


I haven't learned first-order logic in a systematic way.   Question. What is the correct way to write in first-order formulas correctly the following statement?     For any natural number $n$, $P(n)$ is true.     Two candidate I come up with are the following:   $\forall n$ $(n\in{\bf N}\to P(n))$ $\forall (n\in{\bf N})P(n)$   The second one can not be right according to the instruction in  Wikipedia article. However, it is also used in .

What are standard ways to write mathematical expressions involving quantifiers in a (semi)formal way ? In different posts of mine concerning similar question I have encountered for a generic expression of the type "for all $x\in I$ and $y\in J$ holds $P(x,y)$" the following writing conventions  1) $\forall y\in J \ \ \forall x \in I: P(x,y)$ (this was how I would usually write statements in a formal way; sometimes also as  $\forall y\in J: \ \ \forall x \in I: P(x,y)$ ;don't know if it standard)  2) $(\forall y)(\forall x)(x \in I \land y\in J \Rightarrow P(x,y))$  (in the accepted answer from  question)  3) $(\forall y: \ y \in J) (\forall x: \ x \in I) (P(x,y))$ (form the same answer as above)  4) $\forall y \ \forall x\ (x \in I \land y \in J \Rightarrow P(x,y))$  (in the accepted answer from question)  5) $(\forall y\in J )(\forall x \in I) [P(x,y)] $  (in the accepted answer from  question).  ( (I hope I "generalised" them correctly, because at some points, they where written only for one variable, for example 3) was written just as $(\forall x: \ x \in I) (P(x))$ )  Could you tell me which ones are generally accepted an if there is a standard to how these should be written ?  (I think unique readability should be a criterion and I'm not sure the way I'm used to writing mathematical expression satisfies that)


I'm trying to set the ImageIcon for a java application, but when I try to obtain the resource I receive a NullPointerException.  This is the directory structure inside of Netbeans:   project-name   resources -images icon.png src target    Here is the code I'm using to set the ImageIcon:  protected ImageIcon createImageIcon(String path, String description) {     java.net.URL imgURL = getClass().getResource(path);     if (imgURL != null) {         return new ImageIcon(imgURL, description);     } else {         LOG.error("Couldn't find file: " + path);         return null;     } }   I've inserted the following custom code for the iconImage property in Netbeans:  Form.setIconImage(createImageIcon("/project-name/resources/images/icon.png", "Icon Description").getImage());   Any help is greatly appreciated.

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


While I am aware of several other similar question which have been asked in the past, my mathematical education only extends through calculus, making them beyond my comprehension, and I believe this specific problem is harder because of the (2n) component.  I would like to convert the below function into a non recursive one (to reduce its compute time), and would greatly appreciate any explanation for how to do so, especially if they don't require advanced knowledge, or the solution.  Thanks!     $$\begin{align}  R(0) &= 1   \\  R(1) &= 1   \\  R(2) &= 2   \\  R(2n) &= R(n) + R(n + 1) + n \quad\quad (\text{for } n > 1)  \\  R(2n + 1) &= R(n - 1) + R(n) + 1 \quad\quad (\text{for } n \ge 1)  \\ \end{align}$$   (n is a whole number)  Edit: Here is a list of the first 40 elements. [1,1,2,3,7,4,13,6,15,11,22,12,25,18,28,20,34,22,42,27,44,34,48,35,55,38,59,44,62,47,69,49,72,55,81,57,87,65,90,70]

For the recurrence relation:  $f(0)=1$  $f(1)=1$  $f(2)=2$  $f(2n)=f(n)+f(n+1)+n\ \ \ (\forall n>1)$  $f(2n+1)=f(n)+f(n-1)+1\ \ \ (\forall n\ge 1)$  (the first numbers of the sequence are: 1, 1, 2, 3, 7, 4, 13, 6, 15, 11, 22, 12, 25, 18, 28)  Given some number $S$, I would like to find $n$ such that $f(n) = S$, using an approach that runs in $O(\log n)$ time. Any ideas or tips how to solve it? I tried substitution so far but didn't get far.


I am trying to make a method that takes in an ArrayList and a letter. If the words in the arraylist start with that letter, than it will be put into a new array of words that start with that letter. For example, an arraylist with ("Apple", "Anny", "Bob") and a letter of "A" would create a new arraylist ("Apple", "Anny"). I am not allowed to use .startsWith(char ch)  public ArrayList<String> wordsThatStartWith(ArrayList<String> words, String letter) {     ArrayList<String> newWords = new ArrayList<String>();     for(int i = 0; i < words.size(); i++){         if((words.get(i)).substring(i, i + 1) == letter){         newWords.add(words.get(i));     } } return newWords; }   I am not sure why it will not add into a new ArrayList.

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


I am a graduate student and I need a suggestion for a good book in Lebesgue Measure Theory with good exercises and if its possibly with hints or solutions. Thank you.

I post this question with some personal specifications. I hope it does not overlap with old posted questions.  Recently I strongly feel that I have to review the knowledge of measure theory for the sake of starting my thesis.  I am not totally new with measure theory, since I have taken and past one course at the graduate level. Unfortunately, because the lecturer was not so good at teaching, I followed the course by self-study. Now I feel that all the knowledge has gone after the exam and still don’t have a clear overview on the structure of measure theory. And here come my specified requirements for a reference book.   I wish the book elaborates the proofs, since I will read it on my own again, sadly. And this is the most important criterion for the book. I wish the book covers most of the topics in measure theory. Although the topic of my thesis is on stochastic integration, I do want to review measure theory at a more general level, which means it could emphasize on both aspects of analysis and probability. If such a condition cannot be achieved, I'd like to more focus on probability. I wish the book could deal with convergences and uniform integrability carefully, as Chung’s probability book.    My expectation is after thorough reading, I could have strong background to start a thesis on stochastic integration at an analytic level.  Sorry for such a tedious question.  P.S: the textbook I used is Schilling’s book: measures, integrals and martingales. It is a pretty good textbook, but misprints really ruin the fun of reading.


Prove that $n$ is a prime number if and only if $(n−2)! \equiv 1 \pmod n$.  I proved the part where we suppose that the latter is true and prove that n is prime. However, I'm stuck on how to prove the latter is true assuming n is prime. I tried following the proof for Wilson's Theorem, but I'm not sure how to translate it into a proof for $(n-2)!$. Can anyone show me where to start?

I need to show that if $(n-2)! \equiv 1 \pmod n$ then $n$ is prime. I think that if $n$ is composite, then we'll have every factor of $n$ in $(n-2)!$, and it would yield that $(n-2)! \equiv 0 \pmod n$. However, I didn't use the fact that it specifically congruent to $1 \bmod n$, so I think I'm getting something fundamental wrong. Is my solution correct? Why do we demand congruence to $1 \bmod n$?


Is there a safe and sound way to let the insides of a float environment know on which column the float is placed?  Here is an examples that fails:  \documentclass[twocolumn]{article} \usepackage[english]{babel} \usepackage{blindtext} \usepackage{graphicx} \usepackage{float} \usepackage{xparse}  \makeatletter \NewDocumentCommand{\blindfigure}{O{}}{ \begin{figure}[#1] \includegraphics[width=\linewidth,height=.35\linewidth]{example-image-a} \caption{\if@firstcolumn I'm on the left\else I'm on the right\fi} \end{figure} } \makeatother  \begin{document} \blindtext \blindfigure[H] \blindtext \blindfigure[H] \blindtext \blindfigure[H] \end{document}   The second float is reflowed to the second column so it gets tricked:    I'd love to have a solution that works with all float targets (hHtbp!).

For writing my master thesis I have an image in landscape that needs to be oriented correctly when it is eventually printed in a book.  If the page with the image is on the left side (even page number) the image needs to be rotated 90 degrees, if it is on the right side (odd page number) it needs to be rotated -90 degrees. In both cases the bottom of the image needs to be near the spine of the book.  Is there any way to do this automatically without me having to check each time if the image is oriented correctly? I'm using the report documentclass, if that helps.


I'm new in discrete math. Can someone prove simply that a tree with $n$ nodes must have exactly $n - 1$ edges. I have researched the solution but I haven't founded yet. I know of course, a tree with n nodes must have exactly n - 1 edges. But, I can't prove it. Thank you. induction on $n$

How many edges does an undirected tree with $n$ nodes have?


I have an XML file and need to change the value to False. Is there a way to do this with powershell?  <setting name="RecordChatHistory">     <value>True</value>   </setting>

I would like to know if is it possible to modify/create values in XML files using PowerShell. Basically I'm interested in:   Modify values in the XML file or create them if they don't exist (i.e. I need to search the item, create if not exists and modify the value) Deal with different XML syntax in the same XML file like those ones:   Syntax 1:   <settings>   <setting id="Location2" value="Barcelona, Spain"/>   <setting id="Location2id" value="zmw:00000.1.08181"/> </settings>   Syntax 2:   <settings>     <musicplayer>         <crossfade>0</crossfade>         <queuebydefault>false</queuebydefault>     </musicplayer> </settings>   Syntax 3:   <settings>     <skinsettings>         <setting type="bool" name="skin.confluence.HomepageHideRecentlyAddedVideo">false</setting>     </skinsettings> </settings>   Any help would be very appreciated.  Thanks.


As illustrated in the screenshot, the geometry on the non-visible part of the mesh is visible in edit mode, even when the viewport shading mode is set to Solid.    It gets difficult to see and select geometry efficiently when this happens. I've observed that this happens when I set the units to centimeters (also in the screenshot).  Is this a bug? Is there a workaround? If this is a bug, where is the best place to report it?  You can download my .blend file  (size 7.53 MB).

I have recently started using blender and one of the models I'm working on has dark shadows along edges. I started this model from scratch. I can't remember them being there when I first started the model, but I had trouble joining areas together and think I've pressed something I shouldn't have. However, there are so many options I'm not sure what I did.  Here is an image of what I mean   The one on the left has the shadow. As a test I started a new model, which is on the right in the image, and as you can see it doesn't have any shadows.  Also, occluded vertices partially show through the model. Occlusion doesn't work properly.   In orthogonal view small darkened triangles appear along the the edges.    I don't really want to start the model again from scratch so any ideas on how to remove this shadow would be great. Thanks.


What are the differences between Decibel (dB) and Decibel milliwatts (dBm)? I'm most interested in dBm with cell phone signal strength. Please give a  detailed explanation. I'm not familiar with the basics so I didn't understand what I was reading when I googled it.

When working with radios, I've seen the term "dBm". What does this mean?  The  gives a table showing the equivalent power in Watts. Is the dBm output just the power level of a transmitter?  How does this differ from signal strength measured in dB?


I opened a program (.exe) with Microsoft's Notepad, just to see what would happen, and apparently all .exe files now open with Notepad. How do I fix this? Even explorer.exe now opens with Notepad. I am using a Windows 7 computer. I thought (using Task Manager) ending explore.exe and reopening it would fix it but since that opens with Notepad, it didn't. I only have a few programs open that were opened before I messed up, which is how I am able to ask this. Please help!

After (hopefully) scrubbing viruses out of a Windows 7 installation (after deciding not to simply run over the laptop repeatedly with my car), I've got everything almost back to normal. The only lingering issue I have is that for my non-admin users, the ".exe" file extension doesn't work. That is, clicking on the various desktop application links results in a "How do you want to open this?" dialog.  I've been through the alleged registry fixing from "winhelponline" and that had absolutely no effect.  I've tried running "assoc" for the affected users, but it reports the .exe association to be "exefile" even though it persistently does not work.  Right-clicking on a desktop icon and then choosing "start" does successfully open an application, but that's clearly a terrible situation.  For my admin user, things seem to work fine.  What do I need to do to get things working?


Why is in this sentence used bare continuous infinitive?  It is important that the focus of training courses be towards enabling employees to competently perform tasks.

We will make the convention that exact categories be skeletally small.   Is this construction (used in a mathematical context) correct? There is something that strikes me as odd in that "be". Should it be "are"? I know I've seen a similar way of using "be" like that, without conjugating the verb, but I'm not completely sure when it should be used.


I get the above error when I try to use my main font for the math letters. If I leave out the \sqrt[3]{2} bit, it works but gives a load of complaints about not having the OpenType feature 'Style=MathScriptScript' (+ssty) available in Calluna. (If you don't have Calluna: TeX Gyre Pagella shows the same  behaviour.) What can I do?  \documentclass{article} \usepackage{xltxtra} \usepackage{fontspec} \setmainfont{Calluna}% \setsansfont{Calluna Sans} \usepackage{unicode-math} \setmathfont{TeX Gyre Termes Math} % If one ore more of the following three lines are included ... % \setmathfont[range=\mathup/{latin,Latin}]{Calluna} % \setmathfont[range=\mathit/{latin,Latin}]{Calluna-Italic} % \setmathfont[range=\mathbfup/{latin,Latin}]{Calluna-Bold} \begin{document}\noindent\LARGE      % ... this would still work, but fontspec will nag about missing +ssty:     $a = -\frac{1}{2}$\\     % ... but this won't work at all:     $a = -\frac{1}{\sqrt[3]{2}}$ \end{document}

I’m having trouble with XeLaTeX (0.9998) and unicode-math (0.7a). If I use \setmathfont more than twice, the \sqrt command breaks when a superscript is specified.  \documentclass{minmal} \usepackage{unicode-math} \setmathfont{Latin Modern Math} \setmathfont[range=\mathup/{num,latin,Latin}]{Linux Libertine O} \setmathfont[range=\mathup/{greek,Greek}]{Symbola} \begin{document} \[ \sqrt[5]{2} \] \end{document}   If I typeset this code, XeLaTeX will produce the following error  Font \l_tmpb_font has only 8 fontdimen parameters.   If I remove the superscript from \sqrt or remove the last \setmathfont command, the document compiles correctly. I’ve tested this code with several OTF files, and they all produced the same result. (I know the resulting superscript is improperly positioned, but I can work on this once I know the document can be typeset.)   because I believe it’s a problem with the package, but I should have checked here before doing so, and I will gladly close the bug if I find I was doing something stupid.


I have a small star object that I'd like to randomly distribute copies of all over a large space background in Illustrator CC. How can I do this automatically? I've tried to do it manually but the results are never "random" enough, and making it dense enough is very time-consuming.

I am trying to make something similar to this?  Obviously it's possible to make it manually piece by piece, but I am looking for some kind of automated feature in Illustrator to achieve this?  Is this possible?  Thanks man in advance!


I have noticed that all squares, at least up to $19 ^ 2$ can be written as: $a^2 = 5k + p$, where $a \in \mathbb{Z}+\neq 1$ and $k  \in \mathbb{Z}+$ and $p = \{0,\pm1\}$  Some examples:  $4^2 = 5 \cdot 3 + 1$  $13^2 = 5 \cdot 34 - 1 $  What is the intuitive and formal proof to see this?

Use Division Algorithm to show the square of any int is in the form 3k or 3k+1   What confuses me about this is that I think I am able to show that the square of any integer is in the form $X*k$ where $x$ is any integer. For Example:  $$x = 3q + 0 \\ x = 3q + 1 \\ x = 3q + 2$$  I show $3k$ first $$(3q)^2 = 3(3q^2)$$ where $k=3q^2$ is this valid use of the division algorithm?  If it is then can I also say that int is in the form for example 10*k  for example  $(3q)^2 = 10*(\frac{9}{10}q^2)$  where $k=(\frac{9}{10}q^2)$  Why isn't this valid? Am I using the div algorithm incorrectly to show that any integer is the form 3k and 3k+1, if so how do I use it? Keep in mind I am teaching myself Number Theory and the only help I can get is from you guys in stackexchange.


got me thinking. There have been cases, very occasionally, where upon reading the question I get the sense that the asker is looking to do something evil: spam, black-hat hacking, mass email scraping, rootkits and so on.  Typical signs are a new user, asking about a precursor to a sketchy task (for example, ), without contextual details or further explanation.  Judging by the disparity in the ones I'm seeing and the ones I was able to find in search, usually these questions get closed and deleted or go unanswered. Some are answered, though.  I'm curious as to the community's thoughts -- is it our job to be judging askers on their perceived intent? Should we flag for this if we have sufficiently strong evidence the answer will clearly be used for evil purposes, if it's otherwise an on-topic Stack Overflow question?  (It's not as clear-cut as you might think -- as an security researcher I blur this line all the time, and thus have strong feelings about the ethical responsibilities of people who play with that particular fire. There have been times when I've written up a full, complete, multi-paragraph answer, read the question through a few more times, sighed, and deleted the whole thing because I didn't like what I might be helping someone do. I'm curious if anyone else has had this experience, and what they've done: sometimes I've left a comment, but mostly I just move on.)

How should we treat questions that are, or have seeds of, evil or malicious purposes and actions, such as writing spambots and malware?    Should they be answered like regular "everybody keeps their pants on" questions? Or should there be some other type of response to this bad behaviour lot?


Let $G$ be a locally compact Hausdorff group, $H$ a closed normal subgroup. To simplify matters we assume that the underlying topological space of $G$ has a countable base.  Suppose a left Harr measure $\mu$ is explicitly given on $G$.     Can we explicitly construct a left Haar measure on $G/H$ using $\mu$?   The motivation is as follows. When $H$ is compact or discrete, the answer seems to be yes. Suppose $H$ is compact. Let $K$ be a compact subset of $G/H$. Then $\psi^{-1}(K)$ is compact where $\psi$ is the canonical homomorphism $G \rightarrow G/H$. So we can define $\nu(K) = \mu(\psi^{-1}(K))$. Then I think $\nu$ defines a left Haar measure on $G/H$. When $H$ is discrete, $\psi$ is a local homeomorphism. So we can define locally a Borel measure on $G/H$. Then I think we can get it globally.  I have no idea about the answer when $H$ is not compact or discrete.

Suppose I have a locally compact group $G$ and a quotient map $f:G\to G/N$. Is it true that for every Borel-measurable function $f : G → [0, +∞]$, $$\int_{G} f(g) \, \mathrm{d} \mu_G (g) = \int_{G/N} \int_{N}    f(gn) \, \mathrm{d} \mu_{N} (n) \mathrm{d} \mu_{G/N} (gN),$$ where $\mathrm{d} \mu_{G}$, $\mathrm{d} \mu_{N}$ and $\mathrm{d} \mu_{G/N}$ are the Haar measures on $G$, $N$ and $G/N$ respectively?  In particular, is it true that if a subset $A\subseteq G$ is such that its intersection with $\mathrm{d}\mu_{G/N}$-almost every coset $gN$ is of full measure in $gN$ (w.r.t. to the measure on $gN$ obtained by shifting the measure of $N$, which is independent of the choice of $g$), then $A$ is of full measure in $G$? (This is implied from the equation above by taking $f$ to be the characteristic function of $A$).  I wanted to use the  in Wikipedia, but I'm not sure if it applies here. I'm not sure I understand the definition of a Radon space and I don't know which locally compact groups satisfy it.  I know of a more specific disintegration result, which appears in many/most introductions to Haar measures (e.g. Raghunthan's book), but it is only stated for continuous $f$ with compact support. I suppose it's not hard to get rid of the continuous part by using some Luzin argument (although I am not sure how to do it myself), but the compact support bothers me.  In any case, if this is not true for general locally compact groups, for which groups it is true? I have a reference for second-countable compact groups (Halmos's book Measure Theory; his definitions are a bit out-dated, but coincide with the modern ones for second-countable compact groups).  I don't mind assuming separability. Compactness is not awful either, but I prefer not to assume metrisability.  Thanks.


I can't install Steam no matter what I try. Dependencieo over dependencies ... you got it. I tried anything I could, and ended up damaging my system. Now it's like new. Here is the link of tutorial I followed:  Here is what happens when I execute sudo apt-get install steam: techguy@techbook:~/steam$ sudo apt-get install steam Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming.  The following information may help to resolve the situation: The following packages have unmet dependencies: steam:i386 : Depends: libgl1-mesa-dri:i386 (>= 17.3) but it is not going to be installed or libtxc-dxtn0:i386 but it is not installable Depends: libgl1-mesa-glx:i386 but it is not going to be installed Depends: libudev1:i386 but it is not going to be installed E: Unable to correct problems, you have held broken packages.  I tried reconfiguring and adding repositories and anything I could, but that libgl1-mesa problem is still there. I have managed to install steam installer (via .deb) but the problem comes when I launch Steam installer. Here is what happens: Steam needs to install these additional packages: libgl1-mesa-dri:i386, libgl1:i386, libc6:i386 [sudo] password for techguy: ...... Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:   The following packages have unmet dependencies: libgl1:i386 : Depends: libglx0:i386 (= 1.3.1-1) but it is not going to be installed libgl1-mesa-dri:i386 : Depends: libglapi-mesa:i386 (= 20.0.4-2ubuntu1) but it is not going to be installed E: Unable to correct problems, you have held broken packages. Press return to continue:  Any ideas?

I ran the following code and got this package needs these packages, now it also says these packages are suggested, and theses are recommended. How do I get those up to install as well.  myusuf3@purple:/etc$ sudo apt-get install virtualbox-4.0  Reading package lists... Done Building dependency tree        Reading state information... Done The following extra packages will be installed:   acroread ia32-libs lib32asound2 lib32bz2-1.0 lib32gcc1 lib32ncurses5 lib32stdc++6 lib32v4l-0 lib32z1 libaudio2   libc6-i386 libcurl3 libflac8 libhal1 liblcms1 libmng1 libogg0 libpulse0 libqt4-dbus libqt4-network libqt4-opengl   libqt4-xml libqtcore4 libqtgui4 libsdl-ttf2.0-0 libsdl1.2debian libsdl1.2debian-alsa libsndfile1 libv4l-0   libvorbis0a libvorbisenc2 libx11-xcb1 nspluginwrapper Suggested packages:   libldap2 libgnome-speech7 lib32asound2-plugins nas liblcms-utils pulseaudio qt4-qtconfig Recommended packages:   pdf-viewer The following NEW packages will be installed:   acroread ia32-libs lib32asound2 lib32bz2-1.0 lib32gcc1 lib32ncurses5 lib32stdc++6 lib32v4l-0 lib32z1 libaudio2   libc6-i386 libcurl3 libflac8 libhal1 liblcms1 libmng1 libogg0 libpulse0 libqt4-dbus libqt4-network libqt4-opengl   libqt4-xml libqtcore4 libqtgui4 libsdl-ttf2.0-0 libsdl1.2debian libsdl1.2debian-alsa libsndfile1 libv4l-0   libvorbis0a libvorbisenc2 libx11-xcb1 nspluginwrapper virtualbox-4.0 0 upgraded, 34 newly installed, 0 to remove and 26 not upgraded. Need to get 168MB of archives. After this operation, 460MB of additional disk space will be used.   Please and thank you


Suppose I put a pendulum of metal ball and very thin rope in highest achievable vacuum. What would keep it from not swinging forever?

I am attempting to settle a friendly bet.  Would a pendulum swing indefinitely in a hypothetical vacuum (i.e. no air resistance) having a hypothetical frictionless bearing (i.e. no energy lost due to friction) assuming the following   The frictionless vacuum is on Earth (9.8 m/s^2). The pendulum is already in motion and no other external forces other than gravity act on the pendulum.


In a hypothetical circuit with only an inductor and a DC voltage source (no resistance), why is the voltage across the inductor the same as the source voltage? I get that the charges coming from the battery need to lose their energy, so do so over the inductor, but surely when the voltage across the battery and inductor are equal, there is no net voltage acting on the current, and so no change in current and so no back emf? Thanks :)

Suppose we have a circuit with a voltage source, a switch open and an inductor all in series. If we close the switch, the potential difference of the voltage source is instantaneously applied to the inductor. As the current starts to build up, induced voltage from the inductance opposes it. If the induced voltage (back-emf) is equal and opposite to the applied voltage, and the net voltage is zero, what drives the current then? All I could find  was this:     "...it is difficult to realise that there can be a current without a 'resultant' emf. Faraday's law states $e = LdI/dt$ and if there is no resistance $e = E$. It is the electrical analogy of constant velocity with no need for a resultant force. If there is resistance then $e = LdI/dt = E - Ir$ ... 'resultant' $\text{emf} = e$"   Could you expand a little bit more on this idea?


I want to change the color of UITabBar. I used UITabBar by the help of InterfaceBuilder but it doesn't provide the option to change the color of tabbar I want to change by tabBar color to Blue color can any one suggest me the best way of doing this work.  Thanks in adavance.

Is it possible to use custom colors and background images in a UITabBar?  I realize that Apple would like everyone to use the same blue and gray tab bars, but is there any way to customize this?  Second, even I were to create my own TabBar-like view controller, along with custom images, would this violate Apple's Human Interface Guidelines?


Basically, I applied my textures by taking each individual object, unwrapping it in the uv editor, then opening up an image in the uv editor and it would apply the texture in the 3D editor. However, when I render my project none of the textures appear and everything looks odd. I don't know how to set up the images properly with the bee.  For example, here's the uv layout image for the bee's Cube.001:     How do I get that applied properly to the Cube.001 in my project?  Here is   Everything appears purple if the images aren't there and I don't know how to fix that either.

I made a character, and its one of my first times texturing, and I saved my character into a new folder, and when I came back to the model ALL the textures were pink, I used to know what to do, but I stopped texturing, how do I bring my textures back?


My understanding of x:Name vs Name is that some controls have a Name property, that is basically the same as setting x:Name.  Is there an advantage to using Name when it is available over x:Name?  Here's my  for understanding x:Name vs Name.

Sometimes it seems that the Name and x:Name attributes are interchangeable. So, what are the definitive differences between them, and when is it preferable to use one over the other? Are there any performance or memory implications to using them the wrong way?


How to add an other camera and make it active How can toggle between the two cameras?

I have multiple cameras in a scene. What I want to do is to change which one is active. This way I can view the scene from different angles. How would I do this?


I build a regulated dual +/-12V power supply with common GND myself as specified in . Now I would like to run an Arduino from that power supply. Can I simply use two resistors (140 and 100 Ohms) to create a voltage divider (with or without an opamp buffer), or should I use a 5V voltage regulator?

When would you use a voltage regulator vs a resistor voltage divider?  Are there any uses for which a resistor divider is particularly bad?


I have a JPG file with a resolution of 3000x2077. How big can I print this image ?  Thanks in advance

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?


So I have to prove 2 things:   That $\lim\limits_{n \rightarrow \infty}\frac{x^n}{n!} = 0$ where $n \in \mathbb N$ and $x \in \mathbb R, x>0$.  That $\lim\limits_{n \rightarrow \infty}\frac{x^n}{n!} = 0$ where $n \in \mathbb N$ and $x \in \mathbb R$.    For #1, I know that $\frac{x^n}{n!} >0$, which means that I can find an upper bound and use squeeze theorem. For #2, I have no idea where to start.

Why is     $$\lim_{n \to \infty} \frac{2^n}{n!}=0\text{ ?}$$   Can we generalize it to any exponent $x \in \Bbb R$? This is to say, is     $$\lim_{n \to \infty} \frac{x^n}{n!}=0\text{ ?}$$     This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


If $G$ is a trivial group , obviously $Aut(G)$  is  trivial . Does the converse  hold $?$ .  When  we  are  given  that a  group $G$  has  trivial  automorphism  group , can we  conclude  that the group  will  be  trivial $?$ .  I  guess  not . For  one  thing , we know  that  $$G/Z(G)\cong Inn(G)$$. So , $Aut(G)$ being  trivial  would  imply  that $$G\cong Z(G)$$  i.e.  $G$  is  commutative . But I  see  nothing about $G'$s being trivial .   The problem  is  that  while I cannot  prove  it , I  could  not  find  a  counter example  either , from  among  the  groups  I  am  familiar  with .   What  is  the non-trivial  commutative  group  that  has  trivial  automorphism  group  $?$

Well, this is an exercise problem from Herstein which sounds difficult:   How does one prove that if $|G|>2$, then $G$ has non-trivial automorphism?   The only thing I know which connects a group with its automorphism is the theorem, $$G/Z(G) \cong \mathcal{I}(G)$$ where $\mathcal{I}(G)$ denotes the Inner- Automorphism group of $G$. So for a group with $Z(G)=(e)$, we can conclude that it has a non-trivial automorphism, but what about groups with center?


I have an object like this:  var names = { 45: "Jeff", 145: "Peter", 11: "Dandie", 879: "Michael" }   How do I remove "Peter" from the object?

Say I create an object as follows: let myObject = {   "ircEvent": "PRIVMSG",   "method": "newURI",   "regex": "^http://.*" };  How should I remove the property regex to end up with new myObject as follows? let myObject = {   "ircEvent": "PRIVMSG",   "method": "newURI" };


we have    bash -version GNU bash, version 4.2.46(1)-release (x86_64-redhat-linux-gnu)   what is the meaning of the following shell option ( in bash script )  shopt -s nullglob extglob   and what is the opposite way to cancel it?

What is the canonical way for accessing the local documentation on any available Shell Options builtin with shopt?  I'm using Ubuntu 12.04 and can run help shopt to get a description of what shopt does:  shopt: shopt [-pqsu] [-o] [optname ...]     Set and unset shell options.     ...   I can list the various Shell Options and their values (shopt or shopt -p). But how do I find out what each one actually does without leaving the comfort of my Linux box? I'm not looking for . Is there a man page or something I'm missing?


I want to smooth the edges in the red circle but I also want to keep the blue edge rough. I also want to smooth the blue edge along the horizontal line so the sharp cuts between the edges disappear.

How can I smooth all crown but don't smooth the top of the crown? I did a subdivision surface, but this didn't work. All crown became smooth and changed form.


Can someone please explain the difference between a matrix and linear transformation. I know that they can be the same thing, but have been told that they aren't the same thing necessarily. So my question is what is the difference?

I can't understand this:  Given a matrix T =$\small \{T_{ij}\} \in \mathbb M_{mn}$,define a transformation $\small T:\mathbb R^n \rightarrow \mathbb R^m$ as follows:  If   $~~\small T(x_1,\ldots \ldots,x_n)=(y_1,\ldots \ldots ,y_m)$ ,     then $~\small y_i=\sum_{j=1}^{n}T_{ij}~x_j~~$ for all $\small i=1,.....,m$  I can't differentiate between a linear mapping and the matrix of transformation.Aren't they representing the same thing.Please help me understanding the difference between them...


so i tried to do this commutative diagram using tikz. However, no success. I tried using google and reading manuals but unfortunately, i either didnt understand the syntax or it didnt fit my needs. i really could use some help. the diagram itself is pretty basic. i would really a ppreciate it if someone could either help me drawing it or point me towards a good tutorial/manual where i can learn from.  this is the diagram i was trying to do:    thank you very much

Can anyone help me in giving commands for commutative diagrams in LaTeX ? It doesn't seem to appear properly in the LaTeX guides that I have. A command for a simple triangular diagram with arrows associated to maps would be good enough, or maybe some appropriate reference.


Why is it important to run a model with 1 standard error for lasso ml? I am unsure of the importance.

I'm studying LASSO regression, in particular the choice of the optimal tuning parameter.  The glmnet package and the book "Elements of Statistical Learning" offer two possible tuning Parameters: The $\lambda$, that minimizes the average error, and the $\lambda$, selected by the "one-standard-error" rule.  I couldn't find any research or evidence on    the "one-standard-error" rule, and which $\lambda$ I should use for my LASSO-regression.   EDIT: From the textbook elements of statistical learning   "Often a “one-standard error” rule is used with cross-validation, in which we choose the most par- simonious model whose error is no more than one standard error above the error of the best model."


How would I use the accept attribute to only accept generic files (no extension) on selects?  I tried this:    <input type="file" accept="application/octet-stream">     However no files were showing in the file selector.  Thanks.

Implementing a file upload under html is fairly simple, but I just noticed that there is an 'accept' attribute that can be added to the <input type="file" ...> tag.  Is this attribute useful as a way of limiting file uploads to images, etc? What is the best way to use it?  Alternatively, is there a way to limit file types, preferably in the file dialog, for an html file input tag?


I have a question, I have a Lenovo PC, I Want to know if Ubuntu have drivers 100% compatibles

Is there a package of Ubuntu drivers as driver pack solution? I tried to search for it, but I did not find it. If there is, how can I easily get it?


I am using WSL and try to automate a build process via shell script. The process starts with sourcing some exported variables from a file, say /asdf/2.3.4./test, containing a single line of exports: export VAR1="test"  Now I try to source this from a shell script build_lib.sh: #!/bin/sh . /asdf/2.3.4/test  Executing this results in an error: me@here:path/to/build$ ./build_lib.sh : not found.sh: 2: ./build_lib.sh: 3: .: Can't open /asdf/2.3.4/test  However, sourcing from the shell directly works just fine: me@here:path/to/build$ env | grep VAR1 me@here:path/to/build$ . /asdf/2.3.4/test me@here:path/to/build$ env | grep VAR1 VAR1=test me@here:path/to/build$  What am I doing wrong with the script?

I'm trying to run a python script, on a headless Raspberry PI using winSCP and get the following error message:  Command '"./areadetect_movie_21.py"' failed with return code 127 and error message /usr/bin/env: python : No such file or directory.   When I try and run from terminal, I get:  : No such file or directory.   I try a similar python script, in the same directory, with the same python shebang, the same permissions and using the same user pi, and it works.  I also do a ls and I can see the file, so I don't know why it will not run.


I have installed times new roman font through terminal ubuntu 16.04, at the last moment terminal got struck. Now I cant reinstall times new roman font. I ran few commands with following result:  $ sudo apt update   .   . update done $ sudo apt-get install ttf-mscorefonts-installer E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it? $ sudo apt-get remove --purge ttf-mscorefonts-installer E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


I tried to install Anaconda3-4.1.1-Linux-x86_64.sh, but after saving files in terminal an error comes saying permission denied. How can I resolve this?

How to install  on Ubuntu?   Is there a way to use apt-get install?   I only have command line access to my server. How do I install Anaconda on Ubuntu 14.04 from the command line?


I am using the apex pageblock and pageblocksection with lightning LDS. The page block section is not hiding the third column due to rendering issue. Below is the piece of code :  <apex:pageBlock >          <apex:pageBlockSection columns="3" dataStyle="width:10%" labelStyle="width:23%" collapsible="false" >          <apex:selectList value="{!selectedYear}" id="fy" label="Fiscal Year" tabIndex="1" multiselect="false" size="1" styleClass="slds-select">                 <apex:selectOptions value="{!years}" />                 </apex:selectList>                   <apex:selectList id="region" value="{!selectedregion}" multiselect="false" size="1" label="Region" onclick="setPrevVal();"  onchange="showConfirm({!isEdit}, false);" required="true" styleClass="slds-select ">                     <apex:selectOptions value="{!RegionList}"/>                 </apex:selectList>                  <apex:selectList id="month" value="{!selectedMonth}" multiselect="false"                     size="1" label="Month" onclick="setPrevVal();" onchange="showConfirm({!isEdit}, false);" styleClass="slds-select">                     <apex:selectOptions value="{!MonthList}" />                 </apex:selectList>    <apex:selectList id="dsso" value="{!selectedDsso}" multiselect="false" disabled="{!if(selectedMonth == '0',true,false)}"                                  size="1" label="DSSO" onclick="setPrevVal();" onchange="showConfirm({!isEdit}, true);" required="true" styleClass="slds-select">                     <apex:selectOptions value="{!DssoList}" />                 </apex:selectList>                 <apex:selectList value="{!selectedCategory}" id="cat" label="Category" tabIndex="1" multiselect="false" size="1" styleClass="slds-select">                 <apex:selectOptions value="{!categories}" />                 </apex:selectList>                     <apex:selectList id="tfsArea" value="{!selectedTfsAreaNumber}" multiselect="false" disabled="{!if(selectedDsso == '0',true,false)}"                                  size="1" label="TFS Area Number" onclick="setPrevVal();" onchange="showConfirm({!isEdit}, false);" required="true" styleClass="slds-select">                     <apex:selectOptions value="{!TFSAreaNumberList}" />                 </apex:selectList>                </apex:pageBlockSection>          </apex:pageBlock>

I'm trying to have pageBlockSection under pageBlockSection but as shown in the picture the sub-section of pageBlockSection is all the way to right side, how can I have pageBlockSection under pageBlockSection?  Visualforce page:  <apex:actionRegion >  <apex:pageBlockSection title="Employee" id="pbs0" columns="2"   >                <apex:inputField value="{!employee__c.Is_active__c}">       <apex:actionSupport event="onclick" reRender="pbs1,pbs2" />    </apex:inputField>  </apex:pageBlockSection>   </apex:actionRegion>  <apex:pageBlockSection id="pbs1" columns="2" >   <apex:inputField value="{!Employee__c.Start_Date__c}" />   <apex:inputField value="{!Employee__c.End_Date__c}" />   ........  <apex:pageBlockSection id="pbs2" columns="2" title="Related List">     </apex:pageBlockSection>  </apex:pageBlockSection>   Screen shot:


I have some extern c library that need to be used under python environment. So I came across a language called Cython and start to use it. Here is the cython module to use my extern c functions box.pyx cdef class cSignal:     cdef void *addr      def __cinit__(self, char *path):         cfun_getAddr(path, <char **>&(self.addr))          def __call__(self,*arg):         if len(arg) < 1:             return self.read()         else:             self.write(arg[0])      def read(self):         cdef double val         cfun_read(addr,&val)         return val          def write(self, double val):         cfun_write(addr,val)      class Signal(cSignal):     pass  cdef class cPage:     pass  class Page(cPage):     pass  I mange to build this .pyx as a python module and can be imported in python Now I can use another setup.py script to create many instances of Signal class and the names can be based on strings (they will be obtained from text files) import box  pagenamefromfile = ['pageA', 'pageB', ..., 'pageZ'] namefromfile = ['signalA', 'signalB', ..., 'signalZ'] pathfromfile = ['pathA', 'pathB', ..., 'pathZ'] globals()[stringfromfile[0]] = box.Signal(pathfromfile[0]) globals()[stringfromfile[1]] = box.Signal(pathfromfile[1])  After I run my setup.py, I can call them and use them in python like this: x = signalA.read() signalA.write(1)  Question: how can I do something like this (below code doesn't work) import box  globals()[pagenamefromfile[0]].globals()[stringfromfile[0]] = box.Signal(pathfromfile[0]) globals()[pagenamefromfile[0]].globals()[stringfromfile[1]] = box.Signal(pathfromfile[1])  globals()[pagenamefromfile[1]].globals()[stringfromfile[2]] = box.Signal(pathfromfile[2]) globals()[pagenamefromfile[1]].globals()[stringfromfile[3]] = box.Signal(pathfromfile[3])   in such a way that after I call my setup.py, I can do this: x = pageA.signalA() pageA.signalA(1) pageB.signalC(2) y = pageB.signalD  the page class for me it is to organize in a better way, so far I don't need any function inside.

Suppose I have a python object x and a string s, how do I set the attribute s on x? So:  >>> x = SomeObject() >>> attr = 'myAttr' >>> # magic goes here >>> x.myAttr 'magic'   What's the magic? The goal of this, incidentally, is to cache calls to x.__getattr__().


While playing around with a fresh installation of 18.04, I've accidentally selected a photo for my user. I couldn't find an undo or cancel or remove option, so now I'm stuck with a photo on the login screen. Is there any way to return to the default faceless gray avatar?  My workaround would be to create a new user, grab a screenshot, cut the default image and use that as my new "photo" but if there's a real removal option I'd love to know about it.  Update: I did not take a photo with the webcam, just selected one of the provided images, so there is no .face file in my home directory.

A similar task for changing the desktop background, can be achieved using the following script:   FILE="/backgrounds/background.png" gsettings set org.gnome.desktop.background picture-uri "$FILE"   How would I achieve the same result, but with the user's avatar/profile picture?


I would like to see a list of edit suggestions I made to questions and answers by other users.

Is it possible to see a list of all my edits using a query similar to this ?  Can any one give any link to the query?


I've been trying to make a command block that detects when a certain item that has a specific name is placed inside a chest. So far, I've been able to detect when a specific item is in the chest, but without any luck for the custom name. My functioning command is: /execute if block X Y Z minecraft:dispenser{Items:[{id:"minecraft:cobblestone"}]}  I've tried variations of /execute if block -10 71 -54 minecraft:dispenser{Items:[{id:"minecraft:cobblestone"}],tags:{display:{Name:"(name)"}}}  So far nothing involving testing for the item name has worked. How do I make a command to detect a custom named item?

I am making a Minecraft Mini Game adventure map, and one of the levels has a /setblock command, I am using the command in a way to spawn an item in a chest (Wooden Button) I need the wooden button to have CanPlaceOn tag so it can be placed on a log. I have tried this command: setblock 294 5 -1251 minecraft:chest 0 replace {Items:[{Count:1,Slot:0,id:minecraft:wooden_button,CanPlaceOn:[log]}]}`


I found this Integral Online:     $$\int_2^4 \frac{ \sqrt{\ln(9-x)}      }{ \sqrt{\ln(9-x)}+\sqrt{\ln(x+3)}        } dx$$   I realize this has been asked before. My question doesn't so much concern how to get, but is more about an elementary logical point. The idea is to split the integral and use the substitution $u = 6-x$ like so:  $$\int_2^3 \frac{ \sqrt{\ln(9-x)}}{\sqrt{\ln(9-x)}+\sqrt{\ln(x+3)}} dx + \int_2^3 \frac{\sqrt{\ln(u+3)}}{\sqrt{\ln(u+3)}+\sqrt{\ln(9-u)}} dx$$  My question is, what allows me to "put" $x$ back into the second integral, so that I can add the two together?   On second thought, I do have a question about actually solving the problem. How the heck does one see the symmetry about $x=3$? Is the graph of the integrand symmetric about this line? Where is the symmetry "a priori." I am would like to develop such intuition. I realize this takes practice, but there must have been some observation that tips one of to the symmetry about $x=3$.   EDIT: I see that this has been voted to close for being a possible duplicate. I don't think this is the case, since my primary question is about this logically subtlety which, as far as I can see, doesn't seem addressed in the other stackexchange posts. My question is really a general question about "variable transformations" of integrals that just so happened to manifest itself in this problem (a question I have actually had for quite some time).

This is a Putnam Problem that I have been trying to solve (on and off) for two years, but I have failed. I am in Calculus BC. This problem comes from the book "Calculus Eighth Edition by Larson, Hostetler, and Edwards". This problem is at the end of the first section of the chapter 8 exercises. Here's the problem:  Evaluate $$\int_2^4 \frac{\sqrt{\ln(9-x)}\,dx}{\sqrt{\ln(9-x)} + \sqrt{\ln(x+3)}}.$$  Please. Any help is very much appreciated. So are solutions. Thank you!  Edit: I like the solution given, but I was interested to see if there is any other way of doing the problem? I'm excited to see the results.


This question is about a minor change to a header image on the Mathematica Stack Exchange site.  For background information, see:         It's hard to tell what the status of a request to Stack Exchange is. For a while it looked like this image changeover was imminent. Then things have gone very quiet (since the end of May).  My questions:   What is the process for getting (minor) changes like these completed? What expectations on timelines should one have (days, weeks, months, years)? Have other people here had success with making changes like this and, if so, do you have any advise on how to complete this?   Thank you for reading.

I posted a question here on Meta Stack Exchange, or on a per-site meta, regarding a bug I found in the system. I got no comments, or a few comments stating that this is a legitimate bug (and not by design). However, it's been quite a long time, and no official response was ever posted there.  Or, I had an idea for a new feature, but realized it's already requested, either by searching or posting a request myself only to have it closed as a duplicate of the existing one. It's been a while since the original request was filed, but no official response has been made.   I'm aware that staff members are , but either my post isn't about one of the indicated topic areas for which they're accepting escalation requests for that month, or I already flagged to request escalation but it was declined, so the instructions there don't apply for my post.  What can I do to draw attention to meta questions for the SE team, so they can give an official response, and possibly implement the bug fix or feature?  Note: This is different from other general questions which ask for how to get attention for unanswered questions, since the procedures on meta sites are different, and getting an official response isn't necessarily the same as getting a good answer.


I want to prepare Chicken wings more crispy without using micro oven. Can anyone tell me how to prepare it?

I'm trying to develop my own "secret" fried chicken recipe, something that is similar to Popeye's or Church's. I'm a LONG ways from getting there. Here's what I did in my last experiment:   Chicken was marinated in buttermilk with Cajun spices and Tabasco sauce for 24 hours I used a deep fryer and canola oil. 175C. Prior to "dressing" the chicken, I let the excess buttermilk brine drip off the chicken. I then seasoned it with Cajun seasoning I made a batter using an egg, self rising flour, milk, baking powder I also tried using just plain flour for breading   Results:   Using the batter, the chicken came out looking burned and too smooth (didn't have that crunchy look). It burned too much that I couldn't finish cooking the chicken. Using the flour, the chicken came out with a thin crust, somewhat crispy, but also too burnt. Dipping the chicken in the batter AND then flour gave a bulky & crunchy look. However, again, the result looked too burnt.   Modifications:  I then changed the the breading. I used bread flour and corn starch. I dipped the chicken in the batter again, then used the new breading. The bread flour was a bit lighter. And the corn starch was even more lighter. But they were still burn looking (just lighter shades). I also dropped the temperature to 160C.  Results:  Burnt chicken whose crust wasn't really sticking to the skin/meat.  Questions:  Any suggestions on what I can do to improve? I'm guessing something in the batter is causing the burnt coat. What flour should I use? What can I do to make the coat stick to the skin/meat? Any other suggestions on what to do?


I saw someone else had this question for Excel 2010, but it was never properly answered and I will be more specific as to what is happening.  In Excel 2013, only when I am working on a PROTECTED sheet, if I have cell A2 selected and try to use the left arrow key, instead of stopping at A1, it cycles the selection all the way over to AU2!  I've also tried the suggestion to simply use the "home" key to go to the beginning of the row, however, it does not take me to A2, it takes me to E1.   Can anyone help with this??

When I press the left arrow to return to column A - it will not stop at column A but will continue to wrap around to the end (column XEP or something huge like that). How do I make it stop when it gets to A?  Thank you I understand the home key. Let me restate my question. For example I am at cell number BH21 and for what I'm working on I need to use the left scroll button to move quickly along the row until I reach A column. My problem is that moving that quickly the left arrow button doesn't stop when it reaches A column but just keeps going and wraps around to the very end column XEP21 or whatever the end is. I was already using the spreadsheet with no problem then after modifying a few things this occurred.


This code snippet:  public class NumberFormatException extends IllegalArgumentException {  public NumberFormatException (String test) { super (test); }  static NumberFormatException forInputString(String test) {     return new NumberFormatException("Caused By: \"" + test + "\""); } }   throws NullPointerException:  java.lang.NullPointerException  at java.lang.NumberFormatException.forInputString(NumberFormatException.java)   I'm unable to ascertain what value of 'test' can be the root cause of a NullPointerException since in the concatenation, null is printed on the screen if the value of a String is null.

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


Let $F$ be a field with $5^{12}$ elements. What is the total number of proper subfields of $F$?  A) $3$ B) $6$ C) $8$ D) $5$  Explain the concept used to solve the question.

Possible Duplicate:          Field with $2^{15}$ elements  How many subfields? Including trivial one and the whole thing I guess $15$. Right or not my guess? I think every subfield gives a subspace of dimension dividing $2^{15}$. Hence 15 of them?


I want to prove that 4 is not a primitive root modulo n, for $ n \ge  2$   I know how to prove it for any prime n, but I don't know how to prove it for numbers bigger than 2 which are not primes. Thank you for your help!

I wonder why 4 is not a primitive root for any prime p ?  I've been trying to find an answer with no success so far. Any suggestion would be very helpful, thanks in advance !


This might be a stupid question but given Einstein's general theory of relativity $E = m c^{2} $ what is the energy of a black hole? Isn't the mass of a black hole infinite? Wouldn't that be infinity multiplied by the speed of light squared?

I mean besides the obvious "it has to have finite mass or it would suck up the universe." A singularity is a dimensionless point in space with infinite density, if I'm not mistaken. If something is infinitely dense, must it not also be infinitely massive? How does a black hole grow if everything that falls into it merges into the same singularity, which is already infinitely dense?


There are a lot of explanations how the Exceptions works in the Java, that is the root class of the Exception, their ineritance. But few days ago I was asked new question for me: What is exactly reason for Exceptions in the Java? What is the target it in Java. WHY (not what is it or how it works there)? What is you understanding this question and explanation?

My question is what do most developers prefer for error handling, Exceptions or Error Return Codes. Please be language(or language family) specific and why you prefer one over the other.  I'm asking this out of curiosity. Personally I prefer Error Return Codes since they are less explosive and don't force user code to pay the exception performance penalty if they don't want to.  update: thanks for all the answers! I must say that although I dislike the unpredictability of code flow with exceptions. The answer about return code (and their elder brother handles) do add lots of Noise to the code.


I have to remove _ which is as prefix for a file. I used:  for i in _*.txt; do mv ${i} ${i/#_/''}; done   but it does not change the names of the files which has space in between as _abc xyz-abc.txt  I want _ as prefix to be removed from all the files in a directory irrespective of space.

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


How this following code can run without including header file for printf function?  int main(){ printf("%d",1); return 0;}

Session transcript: > type lookma.c int main() {   printf("%s", "no stdio.h"); }  > cl lookma.c Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.762 for 80x86 Copyright (C) Microsoft Corporation.  All rights reserved.  lookma.c Microsoft (R) Incremental Linker Version 8.00.50727.762 Copyright (C) Microsoft Corporation.  All rights reserved.  /out:lookma.exe lookma.obj  > lookma no stdio.h


I need to create a function that pick up  the previous iteration in a loop. I'm starting with an initial value but then I don't know how to use the result for the next iteration  I've tried somethings like this but it doesn't seems to work at all def CBC(P,K,iv):     crypted =[]     first_elem = XOR(XOR(P[0],iv),K)     crypted.append(first_elem)           #inital value     print(crypted[0])     for i in range(0,len(P),1):         while i>0:             prev_crypted = crypted[i-1]             next_crypted = XOR(XOR(P[i],prev_crypted),K)          return next_crypted  print(CBC("hfkeifnskogf","K","I"))

Is there a way to access a list's (or tuple's, or other iterable's) next or previous element while looping through it with a for loop?  l = [1, 2, 3] for item in l:     if item == 2:         get_previous(l, item)


So here is my call   Guid deliveryId = p.DeliveryDomainId; string test = "TEST"; Guid realDeliveryID = Changepoint_Entities.P_BOOST_GENGetCodeDetailId(test, deliveryId);   And this is the method I try to call wich is an SQL procedure, the code is auto generated from a dmx file so I can't change this :   public virtual ObjectResult<Nullable<System.Guid>>P_BOOST_GENGetCodeDetailId(string codeType, Nullable<System.Guid> codeDetail) {     var codeTypeParameter = codeType != null ?         new ObjectParameter("CodeType", codeType) :         new ObjectParameter("CodeType", typeof(string));      var codeDetailParameter = codeDetail.HasValue ?         new ObjectParameter("CodeDetail", codeDetail) :         new ObjectParameter("CodeDetail", typeof(System.Guid));      return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction<Nullable<System.Guid>>("P_BOOST_GENGetCodeDetailId", codeTypeParameter, codeDetailParameter); }   I get this error when compiling :      Error 30  An object reference is required for the non-static field, method, or property 'EBE.Entities.Changepoint_Entities.P_BOOST_GENGetCodeDetailId(string, System.Guid?)'  d:\userfiles\aorset\documents\gitrepo\dpaebe\ebe_final\ebe_final\controllers\datacontroller.cs  462 39  EBE_Final   I am a bit of a noobie in C# so I don't really what I am doing wrong.  Do I need to use statics or something ? Because the call is in a for loop so I don't know what to do. Thanks in advance :)

Consider:  namespace WindowsApplication1 {     public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }          private void button1_Click(object sender, EventArgs e)         {             //int[] val = { 0, 0};             int val;             if (textBox1.Text == "")             {                 MessageBox.Show("Input any no");             }             else             {                 val = Convert.ToInt32(textBox1.Text);                 Thread ot1 = new Thread(new ParameterizedThreadStart(SumData));                 ot1.Start(val);             }         }          private static void ReadData(object state)         {             System.Windows.Forms.Application.Run();         }          void setTextboxText(int result)         {             if (this.InvokeRequired)             {                 this.Invoke(new IntDelegate(SetTextboxTextSafe), new object[] { result });             }             else             {                 SetTextboxTextSafe(result);             }         }          void SetTextboxTextSafe(int result)         {             label1.Text = result.ToString();         }          private static void SumData(object state)         {             int result;             //int[] icount = (int[])state;             int icount = (int)state;              for (int i = icount; i > 0; i--)             {                 result += i;                 System.Threading.Thread.Sleep(1000);             }             setTextboxText(result);         }          delegate void IntDelegate(int result);          private void button2_Click(object sender, EventArgs e)         {             Application.Exit();         }     } }   Why is this error occurring?     An object reference is required for the nonstatic field, method, or property 'WindowsApplication1.Form1.setTextboxText(int)


Show that $$\lim_{n \to \infty} \left\{\frac{(n!)^{1/n}}{n}\right\} = \frac{1}{e}$$   What I did is to let $U_n = \dfrac{(n!)^{\frac{1}{n}}}{n}$ and  $U_{n+1} = \dfrac{(n+1)!^{\frac{1}{n+1}}}{n+1}$. Then  $$\frac{ U_{n+1} }{U_n } = \frac{\frac{(n+1)!^{\frac{1}{n+1}}}{n+1}}{\frac{(n!)^{\frac{1}{n}}}{n}}$$  Next I just got stuck. Am I on the right track, or am I wrong doing this type of sequence?

I'm trying to find  $$\lim_{n\to\infty}\frac{n}{\sqrt[n]{n!}} .$$   I tried couple of methods: Stolz, Squeeze, D'Alambert  Thanks!  Edit: I can't use Stirling.


I have to iterate over 3 triangles (Dreieck x,y,z, IT IS NECESSARY THAT THEY HAVE THESE NAMES), and I want them in one Array.   I have written a method "check If Valid" which checks if it is possible to construct these triangle. If it is possible, it should return "true". I have written a foreach loop and I want that for every triangle in the array dreiecke it should print "true" if it is possible to construct it and "false" if it isn't possible. In my case it throws a NullPointerException.   Is there something wrong with initializing the Array?  public class DreieckTest { public static void main(String[] args) {     Dreieck[] dreiecke = new Dreieck[3];      //triangle     Dreieck x = new Dreieck(1, 7, 5);     Dreieck y = new Dreieck(3, 4, 5);     Dreieck z = new Dreieck(5, 3, 3);      for(Dreieck dreieck: dreiecke) {         System.out.println(dreieck.istGültig());     }    }    }   and here is the class Dreieck:  public class Dreieck { // attribute private int a; private int b; private int c;  public Dreieck(int a, int b, int c) {     this.a = a;     this.b = b;     this.c = c; }  //check if possible public boolean istGültig() {     if (a + b > c ^ a + c > b ^ b + c > a) {         return true;     } else {         return false;     } }

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


I am thinking something which could be similar as Gödel's works - but not with axioms of logical systems, but with symmetries of (theoretical) physical systems.  Such a proof would mean, that adding any new symmetry, would either contradict the others, or it could be derived from them.  I think, having such a proof would mean, that a theory is "ready". For example, I think the Newtonian Mechanics and the SR are probably "ready" in this sense, but I can't proove it.  Furthermore, applying the Noether theorem, it would also mean, that all conserved quantities of a theory were already found.

I'd like to know whether, given a system, there's a way to obtain all the conserved quantities. For instance if the system consists of electric and magnetic fields, the fields must satisfy Maxwell's equations. These equations are invariant under many transformations (Lorentz transformation, rotations, spatial and temporal translations, etc. By the way is there a way, maybe from group theory, to find all the possible transformations that leaves the equation(s) invariant?) which imply as many conserved quantities thanks to Noether's theorem. In wikipedia I can see an equation that seems to give all the conserved quantities () but it involves the Lagrangian and I'm not sure whether the formula is valid for all systems whose Lagrangian is possible to obtain.


Is there a way to join a LAN world on Minecraft without being on the same internet? I tried just typing in the IP but it didn't work, my friend and I want to play together on a LAN world but I don't know how.

I was just wondering if you can make a LAN server then connect being across the world just using the ip address that you get to choose like this  Gamemode: blah, Op: blah  Port, IP Address  12345, 101.game.net


probbaly a bug somewhere, but there's a lot of sports related questions popping up on SO, getting voted down real fast and disappearing. probably a glitch in some other stackexchange site? (for example, see )

Is something wrong with StackOverflow's spam filter? Recently there have been huge numbers of spam topics related to football streaming. They have all been spam flagged and deleted but there are more getting posted all the time, I just flagged another 6 or so a few minutes ago. This has been going on for around 3 days now with these topics getting constantly posted over and over again in the  tag.


When Dropbox (for example) is installed, it adds a “Favorite Item” in the Finder Sidebar Favorite Items List with his own icon and pointing to its custom folder. How do they do it ?  I’ve tried adding with PlistBuddy modifying the com.apple.sidebarlists.plist, but this is too limited, since I cannot add binary data, the bindings, TemplateSystemSelector, and other stuff needed in the array of the dictionary.  Maybe it’s a simpler way through Xcode coding…   Notice that with "Favorite Servers" is easier since it has just a Name and URL, and the icon is not customizable. So I'm not asking about Servers, but Favorites Items ;-)

How come Dropbox gets a non-generic icon in Finder's sidebar, when other directories like Google Drive and Sites (native in OS X before Lion) all have the same generic one?    How can I customise the icons used by the folders in the sidebar? OS X used to show individual icons of all folders there — not any longer.


I know that LaTeX and ConTeXt are extensions of TeX but each is based in a different philosophy. Beyond of its tex engines (ConTeXt works with LuaTeX for example) this question is focused to understand the advantages and disadvantages depending its use.  Where is better use LaTeX or ConTeXt? Why ConTeXt seems less known? Advantages of use ConTeXt instead of LaTeX or viceversa

I’m interested in the differences and commonalities between the “new” (La)TeX processors:   , , and .   Personally, I’ve only used XeTeX so far and without having the time to try out all three systems, I’m having a surprisingly hard time setting them off from one each other.  As I understand it, these systems are actually very different in some regards. So I’m explicitly asking for strengths and weaknesses in every-day use (whatever that is), rather than very special scenarios.  (I’ve already asked a  on Super User some time ago.)


Sometimes when I switch Wi-Fi network or connect to a VPN via Global Protect the memory usage of /System/Library/CoreServices/WiFiAgent.app shoots up and my fans go mental. Why?    This screenshot is one of the worst times it has happened, the usage is not alway consistent sometimes its 2GB, sometimes 6GB etc etc  Basic macbook pro 13" 2017

I was shocked to just find that the Wi-Fi process on my brand new macbook pro is sucking up 3.4 GB of memory. Why is that and how do I reclaim it? I reviewed a few other questions here about this but they don't have helpful answers.  Running Mojave 10.14.5 (18F203)      That 11282 ports looks suspicious. I'd like my memory back, appreciate your suggestions.  Edit: here is the memory pressure graph:    Uptime 3 days and have been using wifi hotspot a lot (while I wait here for AT&T home internet install...)


I am writing a .net core 2.2 C#, code-first, api with a SQL Server backend. It was just requested to make the api a multi-tenant api. So, I added TenantId (INT NOT NULL) to all DB tables, QueryFilters, etc... Everything is working as expected.  I want to ensure I did not and no one in the future will forget to add the TenantId on all inserts. TenantId will always be a value greater than zero. Is there a way in SQL Server to ensure that every insert on every table has a TenantId value that is greater than zero?

This is probably a simple answer but I can't find it.  I have a table with a column of integers and I want to ensure that when a row is inserted that the value in this column is greater than zero.  I could do this on the code side but thought it would be best to enforce it on the table.  Thanks!  I was in error with my last comment all is good now.


I've been an English student since school, however, I always feel like I'm mispronouncing the word "the". Oxford online dictionary defines the pronunciation of 'the' as: /ðə/, /ðiː/, /ðɪ/. So, are the three correct in every situation?, if not, when should I use each of them?

The is sometimes pronounced "tha" (/ðə/) or "thi" (/ðiː/). Which is the correct pronunciation of this word? Are both correct and used interchangeably at specific places? If the second question is correct, please provide the rule of pronouncing at different places.


I would like to know exactly what du and df mean.  The following is an example of the output of the df command.  Filesystem      Size  Used Avail Use% Mounted on ubi0:rootfs     435M  424M   12M  98% / devtmpfs         88M  4.0K   88M   1% /dev tmpfs           248M     0  248M   0% /dev/shm tmpfs           248M  8.4M  240M   4% /run tmpfs           248M     0  248M   0% /sys/fs/cgroup tmpfs           248M     0  248M   0% /tmp tmpfs           248M   72K  248M   1% /var/volatile   And here's the output of du (run in the / directory)   $ du -sh home     255M    home  $ du -sh usr     264M    usr   I thought that ubi0:rootfs included /home and /usr, but the sum of them, 519M,  is larger than the ubi0:rootfs size, 435M.  The result of the free command is as follows.                total        used        free      shared  buff/cache   available Mem:           495M         55M         50M        8.4M        389M        420M Swap:            0B          0B          0B   At first I thought the difference is due to ramdisk, but the free command shows RAM is not used so much.  What is the exact difference between du and df (or is the /usr dir special)?

When I sum up the sizes of my files, I get one figure. If I run du, I get another figure. If I run du on all the files on my partition, it doesn't match what df claims is used. Why are there so many different figures for the total size of my files? Can't computers add?  Speaking of adding: when I add the “Used” and “Available” columns of df, I don't get the total figure. And that total figure is smaller than the size of my partition. And if I add up my partition sizes I don't get my disk size! What gives?


Blender 2.8 isn't recognizing my graphics card for gpu or opencl rendering. I'm using a mac with a Radeon Pro 580 8 GB graphics card. Are there any articles about best graphics card for use in Blender? I'm thinking about buying a new one, since the cpu rendering takes very very long. Any tips would be greatly appreciated!

I've been experiencing loads of crashing while rendering lately, and after doing some testing I've finally isolated it to the GPU rendering. As soon as I change to that from CPU, blender goes down. This is odd, because I did a whole project (cgmastersnet Corvette course) with it on and had zero crashes. I have not updated Blender since then.   I found a thread about this on blender.org ->    They seem to be saying it could be an issue with MacOS High Sierra  (I am not running High Sierra, I am running Mojave 10.14.) This is my system:  Model Name: iMac Model Identifier:   iMac14,2 Processor Name: Intel Core i5 Processor Speed:    3.2 GHz Number of Processors:   1 Total Number of Cores:  4 L2 Cache (per Core):    256 KB L3 Cache:   6 MB Memory: 32 GB Boot ROM Version:   IM142.0130.B00 SMC Version (system):   2.15f7 Graphics card: GeForce GT 755M   And this is my Blender  2.79 - 2017-9-11   I'm wondering if others have solved this issue. I'm confused on what might have changed (other than the project - which is far simpler than a corvette).   I tried removing any recent add-ons I have used in the past few weeks, saved prefs and restarted, but the crash still happens.   Not sure what other info I can provide, please let me know. For now seems I am stuck with CPU rendering, which is a bummer.


I have been searching around a bit for a good regex for email validation, but for most of the ones I am finding I see the people comment saying the regex is outdated, or it doesn't work... so I am hoping that someone can help me out with an email validation regex that is currently valid for all emails...  here's what I have so far : I have seen people saying that emailReg2 is outdated and produces false positives, but haven't seen anything about emailReg1 being outdated.  var emailReg1 = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,6})?$/; var emailReg2 = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;  function IsEmail(email) {   var regex = //which regex do I put here?   return regex.test(email); }   any clarification is greatly appreciated. Thanks!

Over the years I have slowly developed a  that validates MOST email addresses correctly, assuming they don't use an IP address as the server part.  I use it in several PHP programs, and it works most of the time.  However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs).  What is the best regular expression you have or have seen for validating emails?  I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.


I know I should use the triangle inequality.

I need to use $|a+b| \leq |a|+|b|$ to show that $||a|-|b|| \leq |a-b|$ .   I have tried to represent  $||a|-|b||$ as  $||a|+(-|b|)|$ , and then get $||a|+(-|b|)| \leq |a|+|-|b||$ , but that isn't leading me anywhere given $|a-b| \leq |a|+|b|$.


Why can't the "Launcher" Icons be made smaller? At the smallest setting, they are still 4 times bigger than they need to be on a 10" Netbook. The Icons in the "Top Panel" are much smaller and we users don't have a problem selecting them.

Is it possible to make Unity 2D launcher icons smaller or larger than the default size?


Auto signin worked fine on boot until I installed Chromium.  Now the computer signs in on boot, but when i start Chrome, there is a popup asking me enter my keyring ... it gets tedious. Auto signin is all set up under 'users' correctly, so i don't know what is going on. I have seen a workaround that involves setting a blank password.  Not keen on that because of security issues.  Anyone got any other ideas?  Thanks.

I read through all the related answers, but they do not apply to Ubuntu 14.04.  I have no .gnome2 folder and no Passwords and Encryption keys item in the system settings. I tried to crawl through every possible menu, but I could not find out how to do it.  The popup usually pops out when I start Chromium.


For example, I want to bind localhost:2222 to remote:22  I want to be able to do this:  ssh user@localhost -p 2222   and end up on the remote server via SSH  Is this something that can be done using SSH?  All of the examples I've seen are around port forwarding from a remote machine elsewhere.  I just want to port forward LOCALLY to a remote server.  Edit: this is NOT a duplicate of the suggested duplicate.  I am not trying to access a port on a remote machine via a local port.  I just want to alias port X on my machine to 22 on a remote machine.  I'm not trying to tunnel here, which I thought was clear by my example.  Edit2: it it makes it more clear, I essentially want to proxy localhost 2222 to a remote server on port 22.

There is a system B with the following open servers: I have a web server listening on port 80 and a ssh server listening on 22. However, only port 22 is publicly available. Now, I would like to create some kind of tunnel, so that I can access B:80 from A. However, my client computer A that would like to connect to the system B is not publicly open, either.  So, all I have is a client computer A from where I would like to access the server B and, there, an open port 22. On A, no port is open or can be opened.  What (I think) I would need is to open locally (on A) some port that connects in some way through port 22 of B to port 80 on B.  Is this possibly without using any man-in-the-middle open servers with multiple ports?