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I know how to solve for the determinant of a matrix, but I'm struggling to understand what it represents. | What is the geometric meaning of the determinant of a matrix? I know that "The determinant of a matrix represents the area of a rectangle." Perhaps this phrase is imprecise, but I would like to know something more, please. Thank you very much. |
The following repo compiles fine: #include <tuple> #include <vector> class Foo { public: typedef std::tuple<int, int> foo_type; std::vector<foo_type>::iterator Find() { return Listeners.begin(); } std::vector<foo_type> Listeners; }; int main() { Foo foo; auto i = foo.Find(); } But when I template the tuple on P, Q as in the following repo, I get this error: syntax error : missing ';' before identifier 'Find' #include <tuple> #include <vector> template<typename P, typename Q> class Foo { public: typedef std::tuple<P, Q> foo_type; std::vector<foo_type>::iterator Find() { return Listeners.begin(); } std::vector<foo_type> Listeners; }; int main() { Foo<int, int> foo; auto i = foo.Find(); } | In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway? I have the following code: template <typename T, typename Tail> // Tail will be a UnionNode too. struct UnionNode : public Tail { // ... template<typename U> struct inUnion { // Q: where to add typename/template here? typedef Tail::inUnion<U> dummy; }; template< > struct inUnion<T> { }; }; template <typename T> // For the last node Tn. struct UnionNode<T, void> { // ... template<typename U> struct inUnion { char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U }; template< > struct inUnion<T> { }; }; The problem I have is in the typedef Tail::inUnion<U> dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion<U> names a type and not a function? |
I just got a freelance project to design the UI for a website. Can someone tell me what layout (dimension) is used to design a website front end in Photoshop? What are the basic dimensions used? | I do mockups and prototypes of sites and designs all the time, but I've always wondered if there is a standard size or width I should be using. Generally I'll make my document either 1024, 1200, or 2560px wide, depending on what I'm doing. So what do you think? What is a good or standard size for this? |
I'm getting back into the hobby and I've re-read Moldvay's red book and Cook's Blue book and it's all come back to me. I've read the question "" What I need is a list of equivalents from one edition to the other. Most everything is the same; race, class, HP, ability scores, etc. Saving throws seem to be replaced completely with ability checks? Or have they become something else with ability modifiers added in? THACO is out and d20 rolls are in. There is something called BAB? AC flipped and higher is better. Is there a link that lists all the factors and their equivalents? I need just these two but if there is a place with a table for all of the editions that I can cross reference that would help. | I've been out of the loop for a while, and I used to play AD&D 2nd ed, but today I find there are a lot of different versions that have fairly different gameplay. Can anyone summarize the really big differences, the ones (maybe top three?) that are the 'killer features' of the different editions? What makes each edition play differently than the others? |
Is there any word to describe the outcome has deviated from original idea/concept/intention? The result is worse than expected. | A friend has said that there is a word meaning the outcome is something very different from that originally envisaged. For example: The Australian government introduced a "First time home owner" bonus. Where if you were buying your first house you would get a lump sum cash. Of course everyone selling a house in that price backet put the price up by the same amount as the lump sum and first time buyers didn't benefit at all. Does anyone know if there is a word meaning this and what it is? |
I was trying to solve the following inequation: $$ x^2≤16 \Rightarrow x≤\sqrt{16} \Rightarrow x≤4 \text{ and } x≤-4 $$ But the solution given in my textbook is [-4,4], which is only possible when $x≥-4$ and $x≤4$. What have I done wrong? (Sorry I could not format my question properly, I am new to this site.) | Simplify: $x^2 > 1$. My solution: Taking square root on both sides: $±x > ±1$ So my results are: $x > 1$ $x > -1$ $-x > 1$ $\implies$ $(-1 > x)$ $-x > -1$ $\implies$ $(1 > x) $ But I strongly feel this is wrong. What is wrong here? A step-by-step explanation will help me. |
Question to experienced travelers in both economy and business classes. I fly for work, in business. My daughter is flying privately, same flight, in economy. Long transpacific flight. Daughter never flew business, and I’d love to give her such possibility. But I can’t pay 5000 dollars for her business upgrade... Do you think we could just swap boarding passes and places? A year ago same situation happened with my son and flight staff didn’t allow to swap. But with 2 women - how will they know? Thanks | Me and a friend are looking at taking a transcontinental flight together. It appears that for this particular flight, business class is $2000 more than economy. This would be too expensive for us to book, but what if we shared? Would it possible for me to fly in the business class seat for the first half of the flight, then swap with my friend who has booked an economy seat? That way we both get to sleep for half of the flight without spending too much money. |
Let $F$ be a field and let $G$ be a finite subset of $F \setminus \{0\}$ containing $1$ and satisfying the condition that if $a, b ∈ G$ then $ab^{−1} ∈ G$. Show that there exists an element $c ∈ G$ such that $G = \{c^i : i ≥ 0\}$. This is an excercise from the book: The Linear Algebra a Beginning Graduate Student Should Know; Golan | In Grove's book Algebra, Proposition 3.7 at page 94 is the following If $G$ is a finite subgroup of the multiplicative group $F^*$ of a field $F$, then $G$ is cyclic. He starts the proof by saying "Since $G$ is the direct product of its Sylow subgroups ...". But this is only true if the Sylow subgroups of $G$ are all normal. How do we know this? |
Imagine you have a deck of cards and want to be fairly sure that you draw each card once (with a perfectly fair, complete, and random deck on each draw, of course). You are drawing cards in groups of size n from the deck. What is the expected number of draws such that each card has been drawn at least once? Similar to the , but not quite. How would one go about integrating the math for that algorithm with drawing multiple cards at the same time? Edit: found some duplicate questions. | Suppose I have a set of 100 integers. I randomly choose 10 of those, make a note of which ones I selected, and repeat the process. What is the expected number of times this process must be repeated before I see all 100 integers? I'm also greatly interested in how this is calculated as I'm trying to increase the expected number of times this process is repeated by changing the set sizes. |
EDIT : This about explicit notation and clarity, usage of $\sqrt{(-x)^2}= x$ is for demonstrative purposes not for the problem itself. $\sqrt {(-2) ^2} = \sqrt {2^2}$ causing confusion $-2=2$ which is nonsense. What seems to be needed is somehow distinguishing between $-2=2$ and explicitly stating $2,-2$ are in the set $S=$same equivalence class of numbers $k$ s.t. $k^2$ having the same value. Another observation is the order of operation is important, $\sqrt {(-2)^2} = \sqrt {2^2}$ can be evaluated as either $\sqrt {4} = \sqrt {4} =2$ or $ {-2} = {2}$ , how ever implicitly it known that the square function performs first and only after that the square root function can operate, how could this implicit knowledge be worked into explicit notation? Are there any notations that can be used to make order of operation explicitly visible or instead of ending up with $2=-2$, somehow end up with $2 \equiv-2$ with respect to their squares having same values? | I noticed a large portion of general public (who knows what square root is) has a different concept regarding the surd of a positive number, $\sqrt\cdot$, or the principal square root function. It seems to me a lot of people would say, for example, $\sqrt 4 = \pm 2$, instead of $\sqrt 4 = 2$. People even would correct a statement of the latter form to one with a $\pm$ sign. Some also claim that, since $2^2 = 4$ and $(-2)^2 = 4$, $\sqrt 4 = \pm 2$. Some people continue to quote other "evidences" like the $y=x^2$ graph. While most people understand there are two square roots for a positive number, some seem to have confused this with the surd notation. From an educational viewpoint, what might be lacking when teaching students about surd forms? Is a lack of understanding to functions a reason for this misconception? Now I have noticed another that hinted that poster was confused. Following @AndréNicolas's comment below, might these confusion really come from two different communities using the same symbol? |
I want to set a variable if my condition is true on my Ubuntu system. This proves that my if-statement is correct: $ (if [ 1 == 1 ]; then echo "hi there"; fi); hi there This proves that I can set variables: $ a=1 $ echo $a 1 This shows that setting a variable in the if-statement DOES NOT work: $ (if [ 1 == 1 ]; then a=2; fi); $ echo $a 1 Any ideas why? All my indicates that it should work like this... | While reading up on how to set up grub, I came across an article claiming that I need to use one of the following two syntaxes, echo \(hd0,0\) >> /boot/grub/grub.conf or echo '(hd0,0)' >> /boot/grub/grub.conf because, at the command line, parentheses are interpreted in a special way. What is special about the parentheses? How are they interpreted? |
Between Hawking & Ellis and Wald, which one would be the better choice to follow up a graduate-level course in GR (based off of Carroll's book)? If not either of those two, does anyone have any suggestions? I'm interested in those two not only because of the physics they present but also because of their rigor (I'm a post-grad mathematician). | What are some good books for learning general relativity? |
I am building a custom autocomplete field. It worked as in when I type 'a' it shows me all the list of fruits with letter 'a', but when I click on any of the options. I see the autocomplete field 'value'. When users type a, it should show Apple, Avocado. Clicking on any of them, it should show Apple, not fruit-1 in the field. This is the code I am using. Form namespace Drupal\custom_google_search\Form; use Drupal\Core\Form\FormBase; use Drupal\Core\Form\FormStateInterface; use Drupal\Core\Routing\TrustedRedirectResponse; class GoogleSearchAutocomplete extends FormBase { /** * {@inheritdoc} */ public function getFormId() { return 'custom_google_search_autocomplete'; } /** * {@inheritdoc} */ public function buildForm(array $form, FormStateInterface $form_state) { $form['google_places_search'] = [ '#type' => 'textfield', '#title' => t('Searchfield'), '#autocomplete_route_name' => 'custom_google_search.autocomplete', '#value' => 'aaa11', ]; $form['search_in_us'] = [ '#type' => 'submit', '#value' => $this->t('Search'), ]; return $form; } /** * {@inheritdoc} */ public function validateForm(array &$form, FormStateInterface $form_state) { } /** * {@inheritdoc} */ public function submitForm(array &$form, FormStateInterface $form_state) { } } Autocomplete controller namespace Drupal\custom_google_search\Controller; use Drupal\Core\Controller\ControllerBase; use Symfony\Component\HttpFoundation\JsonResponse; use Symfony\Component\HttpFoundation\Request; use Drupal\Component\Utility\Tags; use Drupal\Component\Utility\Unicode; use GuzzleHttp\Client; use GuzzleHttp\Exception\RequestException; use Drupal\Core\StringTranslation\TranslationInterface; use Drupal\Core\StringTranslation\StringTranslationTrait; class AutocompleteController extends ControllerBase { public function handleAutocomplete(Request $request) { // Get the typed string from the URL, if it exists. if ($input = $request->query->get('q')) { $typed_string = Tags::explode($input); $typed_string = Unicode::strtolower(array_pop($typed_string)); $trimed_string = preg_replace("/\s+/", "+", $typed_string); $results = $this->showRelatedPlaces($trimed_string); } return new JsonResponse($results); } public function showRelatedPlaces($trimed_string) { try { $results = [ [ 'value' => 'fruit-1', 'label' => 'Apples', ], [ 'value' => 'fruit-2', 'label' => 'Apricots', ], [ 'value' => 'fruit-3', 'label' => 'Avocados', ], ]; return($results); } catch (RequestException $e) { return($this->t('Error occured.')); } } } Problem is that when I type a in the autocomplete textfield, it shows the fruits label (Apple), but when I click on the fruit label, the field value shows fruit-1. I want to show Apple when users select Apple. PS: I don't want to use the same value for label and value. | I have a textfield autocomplete field that shows a list of full user names and email addresses as designed but when a user is selected, the user id is displayed in the field; not the name and email address. This is the form element: $form['people'] = [ '#type' => 'textfield', '#placeholder' => t('Search by name'), '#autocomplete_route_name' => 'my_module.people', ]; This is the autocomplete handler in the controller: public function handleAutocomplete(Request $request) { $query = $this->database->select('simplenews_subscriber', 'ss'); $or = $query->orConditionGroup() ->condition('pa.address_given_name', '%' .$request->query->get('q') . '%', 'LIKE') ->condition('pa.address_family_name', '%' .$request->query->get('q') . '%', 'LIKE'); $query->leftJoin('simplenews_subscriber__subscriptions', 'sss', 'sss.entity_id = ss.id'); $query->leftJoin('profile', 'p', 'p.uid = ss.uid'); $query->leftJoin('profile__address', 'pa', 'pa.entity_id = p.profile_id'); $query->fields('ss', ['uid', 'mail']); $query->fields('pa', ['address_given_name', 'address_family_name']); $query->condition($or); $query->orderBy('address_given_name'); $query->range(0, 10); $results = $query->execute()->fetchAll(); $users = []; foreach ($results as $user) { $users[] = [ 'value' => $user->uid, 'label' => $user->address_given_name . ' ' . $user->address_family_name . ' (' . $user->mail . ')', ]; } return new JsonResponse($users); } The autocomplete textfield populates properly. I just want the first name, last name and email address to show after a selection has been made. |
dev/sda1: clean, 552599/6111232 files, 7119295/24414464 blocks After I turn on my laptop this message appears. The system never boots, the message just stays there. | On every bootup it's the same: /dev/sda1: clean, 908443/38690816 files, 44176803/154733312 blocks Is it some kind of option Ubuntu uses to ensure filesystem consistency or is there something wrong with my HDD? fsck takes up to 30s while booting and so about triples the time needed otherwise. Full output (partly in German): Begin: Loading essential drivers ... done. Begin: Running /scripts/init-premount ... done. Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done. Begin: Running /scripts/local-premount ... done. Begin: Running /scripts/local-bottom ... done. done. Begin: Running /scripts/init-bottom ... done. fsck von util-linux 2.20.1 /dev/sda1: sauber, 908443/38690816 Dateien, 44176803/154733312 Blöcke udevd[623]: unknown key 'SYSFS{idVendor}' in /lib/udev/rules.d/45-libticables.rules:6 udevd[623]: invalid rule '/lib/udev/rules.d/45-libticables.rules:6' * Starting mDNS/DNS-SD daemon [ OK ] * Starting Reload cups, upon starting avahi-daemon to make sure remote queues are populated [ OK ] * Starting configure network device security [ OK ] * Starting bluetooth daemon [ OK ] ####* Starting all other stuff |
I get confused about how to use "a" and "an" correctly. The question of "a" vs "an" should be decided by the pronunciation of the word that follows the article, right? But I've seen the following sentences on the internet. {Alternatives to the TOEFL (ACT, SAT, IELTS)—Minimum Score Requirements An ACT English subscore of 21 An SAT Critical Reading score of 540 An IELTS (International English Language Testing System) total score of 6.5, with no subscore lower than 6.0} I wonder why "an" is used in the sentence "An SAT Critical Reading score of 540". Shouldn't we say "A SAT Critical Reading score"? Another example, in the following sentence: {The minimum English language requirement of this position is an TOEFL ibt score of 90.} Shouldn't we say "a TOEFL ibt score" rather than "an TOEFL ibt score"? | In the following example, is it appropriate to use a or an as the indefinite article, and why? He ate __ green apple. I know that in the case of just "apple", it would be "an apple," but I've heard conflicting answers for "green apple," where the noun is separated from the article by an adjective. Also, which is more appropriate in this case: He ate __ enormous Pop-Tart. |
I am reading a proof of there are infinitely many primes of the form $4m+3$, but have trouble understanding it. The proof goes like this: Assume there are finitely many primes, and take $p_k$ to be the largest prime of the form $4m+3$. Let $N_k = 2^2 \cdot 3 \cdot 5 \cdots p_k - 1$, where $p_1=2, p_2=3, p_3=5, \dots$ denotes the sequence of all primes. We find that $N_k$ is congruent to $ 3 \pmod {4}$, so it must have a prime factor of the form $4m+3$, and this prime factor is larger than $p_k$ — contradiction. My questions are: Why is $N_k$ congruent to $3 \pmod{4}$? Why must $N_k$ have a prime factor of the form $4m+3$ if it's congruent to $3 \pmod{4}$? It seems that those should be obvious, but I don't see it. Any help would be appreciated! | This is the proof from the book: Theorem. There are infinitely many primes of the form $4n+3$. Lemma. If $a$ and $b$ are integers, both of the form $4n + 1$, then the product $ab$ is also in this form. Proof of Theorem: Let assume that there are only a finite number of primes of the form $4n + 3$, say $$p_0, p_1, p_2, \ldots, p_r.$$ Let $$Q = 4p_1p_2p_3\cdots p_r + 3.$$ Then there is at least one prime in the factorization of $Q$ of the form $4n + 3$. Otherwise, all of these primes would be of the form $4n + 1$, and by the Lemma above, this would imply that $Q$ would also be of this form, which is a contradiction. However, none of the prime $p_0, p_1,\ldots, p_n$ divides $Q$. The prime $3$ does not divide $Q$, for if $3|Q$ then $$3|(Q-3) = 4p_1p_2p_3\cdots p_r,$$ which is a contradiction. Likewise, none of the primes $p_j$ can divides $Q$, because $p_j | Q$ implies $p_j | ( Q - 4p_1p_2\cdots p_r ) = 3$, which is absurd. Hence, there are infinitely many primes of the form $4n +3$. END From "however, none of the prime ...." to the end, I totally lost! My questions: Is the author assuming $Q$ is prime or is not? Why none of the primes $p_0, p_1,\ldots, p_r$ divide $Q$? Based on what argument? Can anyone share me a better proof? Thanks. |
We place $n$ points on the unit circle uniformly and independently . What is the probability that their convex hull does not contain the origin? I came up with this: If the convex hull does not contain the origin then there is one point $x$ such that the next point $y$ in clockwise order forms an angle $xOy$ larger than $\pi$. Therefore we just need to calculate the probaility that this happens at least once, but notice that this cannot happen more than once . Suppose that $x_1,x_2,\dots x_n$ are the points that are to be placed independently, then the probability that the next point after $x_i$ forms an angle larger than $\pi$ is $\frac{1}{2^{n-1}}$. Therefore the probability the hull does not contain the origin is $\frac{n}{2^{n-1}}$ I would greatly appreciate a proof verification, alternative proofs and insight as to whether this can be generalized to higher dimensions, when there are $d+2$ points it is possible, as is shown . | What's the probability that a n-sided polygon made from n distinct random points on circle contain the centre? |
No doubt an easy question: I'm trying to follow Wikipedia's (second) proof of the irrationality of $\sqrt{3}$ and it relies on the notion that since $3n^2 = m^2$ is divisible by 3 then so is $m$. Why is this so and can you help me prove it? | This is a problem from "" (specifically, exercise set 2 #9), which is one of my math texts. Please note that this isn't homework, but I would still appreciate hints rather than a complete answer. The problem reads as follows: If 3p2 = q2, where $p,q \in \mathbb{Z}$, show that 3 is a common divisor of p and q. I am able to show that 3 divides q, simply by rearranging for p2 and showing that $$p^2 \in \mathbb{Z} \Rightarrow q^2/3 \in \mathbb{Z} \Rightarrow 3|q$$ However, I'm not sure how to show that 3 divides p. Edit: Moron left a comment below in which I was prompted to apply the solution to this question as a proof of $\sqrt{3}$'s irrationality. Here's what I came up with... [incorrect solution...] ...is this correct? Edit: The correct solution is provided in the comments below by Bill Dubuque. |
As the title says I want to open the terminal from the folder itself. For ex:- If I am in folder "A" and I press f12(function key 12) the terminal should open up IN the folder "A". | How can I create a keyboard shortcut so that when I press F12 in nautilus (or desktop), I get a terminal in the current directory? |
I would want to ask you why was this a split pot. | In Texas Hold'em poker, there are some cases where a particular card, often called kicker, acts as a tiebreaker between players to determine who wins the pot, or if the pot has to be shared. For some combinations such as three or four of a kind, there is no doubt: the kicker is the 5th card of the chosen combination, and determines the winner. Example Alice has 7 and 10 Bob has 7 and K On the board are 7, 7, 2, 3, 4 In that case, both have a three of a kind. But because Bob has a king and Alice only a 10, he wins. Most of poker websites explaining the rules clearly mention the role of the kicker applying to three of a kind and double pairs. But much fewer say something about colors, straights and full houses, and I found many contradicting answers. I also asked the question to some used online poker players and they also gave me contradicting answers. I have tried to search for official tournament rules, but most of them only explain what happens with bad behaviors, bad deals, incorrect or confusing betting, showing cards when you shouldn't, acting when it's not your turn, etc. without mentioning subtleties about combinations at all. To simplify my question, I will take three examples; I think it's better to start with examples before getting to the general answer if one exists. So, what's happening in the following 3 examples? Could you give a more generalized answer? Example 1 - Flushes Alice has 2♣ and 3♣ Bob has 4♣ and 5♣ On the board are 6♣, 8♣, 10♣, 2♥, 5♦ Contradicting answer 1: it's a tie, because the highest card included in the flush is the 10, which everybody chooses to include in their 5 showdown cards. Contradicting answer 2: Bob wins, because he has the greatest private card that is part of the flush Example 2 - Straight Alice has 6 and K Bob has 6 and J On the board are 4, 5, 7, 8, 10 Contradicting answer 1: it's a tie, because the greatest card in the straight is the 8 for both Alice and Bob Contradicting answer 2: Alice wins, because she owns an extra king, compared to the jack of Bob Example 3 - Full house Alice has 3 and 7 Bob has 3 and 6 On the board are 3, 3, 2, 2, 5 Contradicting answer 1: it's a tie, because one is supposed to choose only five cards to make a combination, and a full house is already five cards. There couldn't be any kicker, and thus their showdowns are strictly equals. Contradicting answer 2: Alice wins because of her extra 7, compared to the 6 of Bob Thank you very much for your answers. Note: I'm unable to post next to you, so I edit my own post; strange not be able to answer to an answer. Ok, So if I summarize what you are saying : In the flush case, Bob wins because at some point, their hand differs. Technically, I can continue comparing the highest private card to decide who wins. I had it correct. In the straight case, if the highest card of the straight is public, then it's technically always a tie, no matter what the players had as second private card (asuming that only one of the two cards was part of the straight). In a full house if both players have the same triplet and the same pair, it's always a tie, no matter what the players had as second private card (assuming again that only one of the two was part of the full house). Please confirm me that what I summarized is correct. Thank you for your answer. |
Suppose I am trying to tell someone, how much distance google maps shows if we take car or on foot. How would I say this? "My house is 10KM from here by car and 8 KM by/on foot." I think "by" is used for means of transport but is it correct to use this here or "on" foot sounds appropriate? | He went there on foot. Or He went there by foot. Which one is correct, and on what basis? |
Short. I am moving a database and webpage. It is now an exact copy but on the webpage it doesnt display the swedish characters correctly. Example VÃƑ„RMARE should be VÄRMARE In the old database it is VÄRMARE in the new it is VÄRMARE It is an old webpage on an old php version that when i am moving will be a much later php version and a mariaDB. I think it has to do with the collation in the database for the tables but in phpmyadmin 2.11.8.1 i can't se collation for the columns. In the head i define <meta charset="utf-8"> I don't even know where to start troubleshooting. Any suggestions how to troubleshoot would be amazing for me. | I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur? This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2. |
My hash contains key that has multiple values(contains duplicates) and keep the value unique so my output looks. $VAR1 = { 'One' => ['code','links','links'], 'Two' => ['indent','indent'], }; I need the hash output as below `$VAR1 = { 'One' => ['code','links'], 'Two' => ['indent'], };` Please advice, Thanks. | I have an array in Perl: my @my_array = ("one","two","three","two","three"); How do I remove the duplicates from the array? |
I have just read that in Windows Vista and above, when you "Safely Remove" a device the USB port is not disabled and data can still be transferred. I know that you can change this behavior so that the port is disabled, but without this 'fix' is there any point in safely removing devices? | I often pull out the USB stick without having to first eject USB, but so far I have not had any problems. Would this lead to problems in the future? |
Trying to find the folder that contains the Wallpapers for 14.04, I want to use some of them on my other computers. | Please see the picture below. Where are the Unity desktop wallpapers located? |
Use integration by parts to calculate 𝐼 = f e^(ax) cos 𝑏𝑥 𝑑𝑥 for 𝑎 ≠ 0 and 𝑏 ≠ 0. This is my working so far. The part where i have to integrate is confusing so with some help maybe i can do it . | I am curious about the proof of these two integrations. It would be great if you could point me in the right direction : $ \int{e^{ax}\cos({bx})dx}= \dfrac{e^{ax}}{a^{2}+b^{2}}[a\cos(bx)+b\sin(bx)] + C $ & $ \int{e^{ax}\sin({bx})dx}= \dfrac{e^{ax}}{a^{2}+b^{2}}[a\sin(bx)-b\cos(bx)] + C $ |
My VPS sometimes goes wild because of /tmp/.X17-unix/.rsync/c/lib/64/tsm --library-path /tmp/.X17-unix/.rsync/c/lib/64/ /tmp/.X17-unix/.rsync/c/tsm64 -t 302 -f 1 -s 8 -S 8 -p 0 -d 1 Any idea what it is and what does it do? And more important, how can I make sure it dosn't kill my VPS? Thanks edit: after killing the pid and restarting the VPS, I'm now seeing 3 pids that kills my CPU with just "./cron" in the command. I tried cd-ing into .X17-unix to see what's in there but it says the folder does not exist. After killing the ./cron pid, it is quiet but I guess it will return at some point. The user is root so I can't kill this user, please help. | This is a about Server Security - Responding to Breach Events (Hacking) See Also: Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism: What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning? Original Version 2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a attack on our provider. The servers access to the Internet has been shut down which means over 5-600 of our clients sites are now down. Now this could be an FTP hack, or some weakness in code somewhere. I'm not sure till I get there. How can I track this down quickly? We're in for a whole lot of litigation if I don't get the server back up ASAP. Any help is appreciated. We are running Open SUSE 11.0. 2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed to resolve this problem, although it may not apply to many others in a different situation. I'll detail what we did. We unplugged the server from the net. It was performing (attempting to perform) a Denial Of Service attack on another server in Indonesia, and the guilty party was also based there. We firstly tried to identify where on the server this was coming from, considering we have over 500 sites on the server, we expected to be moonlighting for some time. However, with SSH access still, we ran a command to find all files edited or created in the time the attacks started. Luckily, the offending file was created over the winter holidays which meant that not many other files were created on the server at that time. We were then able to identify the offending file which was inside the uploaded images folder within a website. After a short cigarette break we concluded that, due to the files location, it must have been uploaded via a file upload facility that was inadequetly secured. After some googling, we found that there was a security vulnerability that allowed files to be uploaded, within the ZenCart admin panel, for a picture for a record company. (The section that it never really even used), posting this form just uploaded any file, it did not check the extension of the file, and didn't even check to see if the user was logged in. This meant that any files could be uploaded, including a PHP file for the attack. We secured the vulnerability with ZenCart on the infected site, and removed the offending files. The job was done, and I was home for 2 a.m. The Moral - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole world is made aware of the vulnerability. - Always do backups, and backup your backups. - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server Fault. |
I every so often hear claims like: M-Theory predicts that there are 10 spatial dimensions! Now I'm not really sure what these claims mean. There are three spatial dimensions that I normally observe so 7 of these dimensions must be different in some way. (Several seconds of researching reveals that the difference is that these dimensions are compact and have very small measure which explains why they are not apparent in every day life) However there are a ton of dimensions that are not quite like our three spatial dimensions. Time is the one that very clearly springs to mind, but we could also talk about momentum. In fact dimension is pretty frequently used to mean unit (e.g. dimensionless, dimensional analysis). So there must be some thing relevant about these 7 spatial dimensions that is not relevant with these other dimensions. My question then is: What is the relevant factor that unites the spatial dimensions not present in other dimensions? For example if I discovered (or theorized) a new degree of freedom, how would I determine if it corresponded a spatial dimension? What properties would it need to count as spatial? helps explain the difference between spatial and time dimensions with respects to the Minkowski tensor, but I would like to see a more authoritative answer that would allow me to fully categorize a potential new dimension. I am looking for a definition that is rather precise rather than intuitive. I have plenty of intuition as to what space is since I live in it and all the sources I can find a couple describe the intuition (e.g. the ). I am curious about a more mathematized definition. Some notes in response to comments: I am already very well aware of what a dimension in general and this question is asking about how we separate dimensions into spatial and non-spatial. I already understand compactification. I am not at all confused by the concept and I am not asking for an explanation of compact dimensions. | How do you exactly define what is and isn't a ? I heard somewhere that it is "anything you can move through" but if that is right, why wasn't time and space considered a dimension before Einstein? |
Can anyone help me finish this proof? Prove that $$\lim_{x\to 2} \left(x^3\right) = 8$$ $|x^3-8|=|(x-2)(x^2+2x+4)|=|x-2|<1$ $$1<x<3$$ | I am concern about the delta calculation given $0 < x < 4$. I believe it works, but I am not 100 percent sure as I am new to proofs. Consider the function $f(x) = x^3$ for $x ∈ ℝ$ and $0 < x < 4$. Prove that $$\lim _{ x\rightarrow 2 }{ { x }^{ 3 }=8 } $$ Proof: Let $\varepsilon > 0$ be given, then let $\delta = \min {(\varepsilon/19,1)}$. Now suppose $|x -2| < \delta = \min {(\varepsilon /19,1)}$. Then $|x^3 - 8| = |x - 2||x^2 + 2x + 4|< |x - 2|<19$ $(|x^2 + 2x + 4| < 19~\text{if}~|x - 2| < 1)< \varepsilon /19 $ $(|x - 2| < \varepsilon /19 )= \varepsilon $. Thus this $\delta$ makes $|x^3 - 8| < \varepsilon $ whenever $0 < |x - 2| < \delta$. Therefore, it follows that $\lim _{ x\rightarrow 2 } x^3 = 8$. |
just installed LAMP server and need to use vim editor to edit php.ini The command sudo apt-get install vim gives me the following error: Package 'vim' is not available but is refered to by another package. This means the package is missing or is obsolete, or is only avaiable from another source. E: Package 'vim' has no installation candidate Please advise | I am running Ubuntu 11.10, as Xubuntu, in an AMD 64 pc, configured as dual boot with Windows 7. I tried installing vim with this: sudo apt-get install vim I got this error message: The following packages have unmet dependencies: vim : Depends: vim-common (= 2:7.3.154+hg~74503f6ee649-2ubuntu2) but 2:7.3.154+hg~74503f6ee649-2ubuntu3 is to be installed E: Unable to correct problems, you have held broken packages. I only have a very faint idea of what the problem is, and none whatsoever on how to correct this. Hope you guys can help. |
I have a direct download link address to a compressed zip file that contains an installer of program that I would like to install. That being said I will only ask one question at a time... How would I download and save it to disk ready for the next step of unzipping it in code? Is there a specific module that deals with this? Can it be done silently in the background without opening up a browser? Any help would be very much appreciated Thanks in advance | I have a small utility that I use to download an MP3 file from a website on a schedule and then builds/updates a podcast XML file which I've added to iTunes. The text processing that creates/updates the XML file is written in Python. However, I use wget inside a Windows .bat file to download the actual MP3 file. I would prefer to have the entire utility written in Python. I struggled to find a way to actually download the file in Python, thus why I resorted to using wget. So, how do I download the file using Python? |
I am running sage evolution 200 on a cloud server. Until recently the program was running fine. Then the cloud host decided to block UDP port 1434 on their router as they claim it was being attacked. When I use port query, it return TCP port 1433 is listening but port 1434 is filtered. I contacted my cloud server provider and was advised to change port 1434 to another port number. I am not a computer expert by any means and need assistance is changing this port even though it's the official port for SQL Server. | I realize that you can change the default instance from the default port of 1433, and equally you can make named instances use static ports as opposed to dynamic ports, but in general are named instances more secure than the default instance against external intruders? Here's why I would think that's the case: Named instances are (again, by default I realize) utilizing dynamic ports. If you move the SQL Browser service to listen on a different port than 1434 then that would be even better, I imagine. A default instance is pretty easy to figure out as the data source. It's just the server's name. But the named instance is an extra step to retrieving the data source with the serverName\instanceName schema. What are some thoughts on this? Am I way out in left field and it makes no difference? |
I often see people researching (2+1)-Gravitational theories such as Chern-Simons. Why is it interesting or what's the motivation underlying that study if there are 4 macroscopic dimensions? | The last decades there has been a lot of research going on in the the area of three dimensional gravity. The motivation, I understand, is threefold: Whereas gravity is not perturbatively renormalizable in four spacetime dimensions, in three dimensions it is. To make it even more interesting it has black hole solutions and it is exactly solvable. This opens the way to to study quantum black holes. This make three dimensional gravity a very interesting system on itself. Through the AdS/CFT correspondence there is a connection between conformal field theories (CFT) in two dimensions and gravity in three dimensions. CFT's are important in condensed matter physics and one can use 3D gravity to learn more about them. Gravity in three dimensions is simpler to deal with then gravity in four dimensions. Therefor it can be used as a toy model for gravity in four dimensions. I am wondering what are the most important insights that 3d gravity brought in these respects? In particular I am interested in point three: did 3d gravity provide any new view on 4d gravity so far? |
I recently installed Ubuntu 13.04 with dual boot to Win 7 without any issue. The login screen came up on Ubuntu with two accounts (Guest & myname). I was able to login as guest but not through my name it said "Invalid password please try again". I have tried all possible passwords that i know off. Could anyone please suggest. Thanks | I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there. I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution? |
Let $X \neq \lbrace 0 \rbrace$ be a reflexive space, and let $f \in X'$. Show that there exists $x \in X$ with $\|x\|=1$ and $f(x)=\|f\|$. The definition of a reflexive space: $X$ is called reflexive if $J_X(X)=X''$ where $J_X: X \to X''$ defined by $J_Xx(f)=f(x)$ with $x \in X$ and $f \in X'$. How to find this such $x$? | Let $X\ne\{0\}$ be a reflexive space and let $f\in X^*$, where $X^*$ is the dual of $X$. I want to know: in general, does there exist an $x\in X$ with $\|x\|=1$, and $f(x)=\|f\|$, where $\|f\|$ is defined as $\sup\{|f(x)|:x\in X,\|x\|=1\}$? I know this is true for $\mathbb{R}^n$ with the norm from the standard inner product, but I'm wondering if it is true in general. |
The flag window on (a comment to) the last question is hidden beneath the answer box, as shown in the following screenshot: Linked: , which is currently - this is not fixed for flags on comments! | There is a strange display issue with the comment flag popup. When I open a comment from the Data Explorer, the comment appeared in the top of the page. Then I click the flag link, the popup box is appeared but overlapped with the Answer box. This strange issue occurs when the comment's answer have the negative points and the answers are ordered by votes. But I can manually click the partial visible part of the popup to flag the comment. Initially I found the issue in Stack Overflow and posted in its . Later I see the same issue in other SE communities too, so I posted here. The following sample comments with negative votes, can be produce the issue: The same is in the below GIF format: It happened in the Google Chrome, Mozilla Firefox and Internet Explorer browsers. |
I have recently watched a video by "Undefined Behavior", explaining countable and uncountable infinities, and showing why uncountable infinity is larger than countable infinity. He then stated that a question had been asked if there is some infinity that's in-between the two (larger than countable, but smaller than uncountable), and that it has been proven that this question in unsolvable. However, he did not mention any name of the theorem proving this, and also did not show any proof. What is the proof that this problem is unsolvable? | I'm making my way through Thomas W Hungerfords's seminal text "Abstract Algebra 2nd Edition w/ Sets, Logics and Categories" where he makes the statement that the Continuum Hypothesis (There does not exist a set with a cardinality less than the reals and no set strictly greater than the natural numbers.) is neither true or false. This is utterly baffling to me, If it's possible to construct a set between $\mathbb{N}$ and $\mathbb{R}$ then this statement is demonstrably false, but if not then the statement is true. This seems to be a straitforward deduction, but many with a more advanced understanding of the topic matter believe CH to be neither. How can this be? |
I’m looking for a book I last read in the late 1970s to early 1980s. The main character was a young male humanoid whose skeleton had been enhanced with titanium to increase its lightness and strength. I think this character ended up leading some sort of battle against a rival faction or planet. | I remember that the main character is trying to find the group that destroyed his home planet while he was on a mission. His planet was very difficult to live on and the people became expert in martial arts and were the best soldiers in the galaxy. They were mercenaries and often helped against tyrants. There was a very memorable section in at least one book about an initiation task that the main character had to do in that he had to survive in their wilderness for days. He was at some point surrounded in a old building by thousands of poisonous worm/snake creatures that he managed to survive until rescued by the leaders. |
I had just arrived home last night when I remembered that I had left my keys in the office I had arrived home last night, and only a short time after that, I remembered that I had left my keys in the office These two have the same meaning, right? | I had just arrived at the hotel, checked in and gotten into my room. Just as I was about to unpack, I noticed that one of my bags was missing. At first I thought I had left it back at the airport, but it turned out that I had left it on the taxi. Here, what's the meaning and role of "just"? Why do you guys input the word "just" here? What exactly does the word do grammatically? Could you help me? |
I have a problem - I bought a book "Introduction to Time Series and Forecasting" by Brockwell and Davis. The first chapter was ok, but now at chapter 2 I am totally lost - I cannot figure the main idea of the explanation, and I cannot figure the intermediate steps in the author results - so the maths becomes useless. I have no background in stochastic processes. Can someone recommend a book similar to Brockwell & Davis in contents, but where proofs are given without "It can be shown that..." (with intermediate steps), and which has a more coherent explanations since I do not understand anymore why the author is giving the details of all these propositions in Brockwell book. I need the book for self-study. | I started by Time Series Analysis by Hamilton, but I am lost hopelessly. This book is really too theoretical for me to learn by myself. Does anybody have a recommendation for a textbook on time series analysis that's suitable for self-study? |
Do departments look at MOOC's certificates favorably during the graduate admissions process? Will it give me any advantage over students who don't have them if I am trying to enter a PhD program? | I'm preparing my application for a master degree scholarship, would it help to put the MOOC's I took in the application, I earned five MOOC certificates and expecting another two in the near future. |
I would like to show that a bounded linear operator $T: \ell^2(\mathbb{N}) \rightarrow \ell^1(\mathbb{N})$ cannot be surjective. If we assume surjectivity, then by the Open Mapping Theorem, $T$ is an open map, i.e. for every open $O \subset \ell^2(\mathbb{N})$, its image $T(O)$ is open in $\ell^1(\mathbb{N})$. Is it then possible to contradict Baire's Theorem by constructing a sequence of open dense subsets of $\ell^1(\mathbb{N})$, whose intersection is not dense? Any help pointing me into the right direction would be appreciated. | The second part of an exercise asks that I show: There does not exist a surjective bounded linear map from $\ell^2(\mathbf{N})$ to $\ell^1(\mathbf{N})$. The first part was to show that these two spaces are separable in their respective $L^p$ norms. I've really hit a wall on this one. I know, in fact, that there does exist a surjective bounded linear map from $\ell^1(\mathbf{N})$ to $\ell^2(\mathbf{N})$. So my intuition says that if there were also one going the other way, then the two spaces would have to be isomorphic, which is false . But I don't know of any such theorem that I could apply to "the category of Banach spaces". My only other idea is to argue by contradiction using the open mapping theorem, but nothing is coming to me... My guess is that separability is also going to be important, given the first part of the exercise. -Thanks. |
I am using First difference transformation, where my variables are represented in a logarithmic form. How do I interpret the coefficients from such regressions? Thank you in advance! | My problem is interpreting coefficients of such time series model: \begin{equation} \ln Y_t - \ln Y_{t-1} =b_1 \cdot \left(X_{t}-X_{t-1}\right)+b_2 \cdot Z_t.\end{equation} I don't know how to interpret coefficients $b_1$ and $b_2$. Hope that someone can help. |
When surfing to any subfolder in my web site the browser displays the list of files in that directory. I would like to add an empty index.html file to fix this, How can I do it with a shell script or a CLI command? You could disable directory indexes. Via .htacces: put this line in the root .htaccess: Options -Indexes | When I access a directory hosted by Apache that does not have a index.php file or similar, Apache lists the content of the directory for me. How can I block this? I'm using Apache2 on Ubuntu. |
In terms of the phonetic symbol, how can I write the symbol t̬ , a "t" with an upside down "^" under it? | So $\hat x$ and $\widehat x$ give upper hats of different length, however, unlike \overbrace{} had an \underbrace{}, one sometimes needs an \uhat and \uwidehat. What is the best (cleanest, fewest conflicts with possible usage, e.g, as interval endpoints in a definite integral, ie, scale properly) to get a underhat and underwide hat (same hats, but flipped, and below the symbol in question). I suppose one can use \documentclass{article}\usepackage{amsmath,mathtools,amssymb} \newcommand*{\uhat}{\underset{\mathrel{\text{\raisebox{.25ex}{\rotatebox[origin=c]{180}{$\wedge$}}}}}} \newcommand*{\uwidehat}{\underset{\mathrel{\text{\raisebox{.25ex}{\rotatebox[origin=c]{180}{$\widehat{~}$}}}}}} \begin{document} $\uhat x ~ ~ \uwidehat X$ \end{document} But there must be better ways. |
I am trying to draw a nice multi-dominance. I find the gap between the two lines above "V" is ugly. Is there any way to move the lower end of the line in red square so that the two lines meet at one point right north of "V"? Thank you very much. \documentclass{article} \usepackage{forest} \begin{document} \begin{forest} where n children=0{tier=CV}{} [\sg [C, tier=CV] [\mo[, tier=CV, no edge][V, name=V, tier=CV]] [\mo, name=mo[, no edge, tier=CV]]] \draw (mo)--(V); \end{forest} \end{document} | I'm trying to draw a specific tree, with two parents node linked to the same child. The problem is that one of the parent is outside the main tree. Here's the code I have for the moment: \documentclass{article} \usepackage{tikz-qtree,tikz-qtree-compat} %\usepackage{gb4e} \usepackage{forest} \begin{document} %\begin{exe} \begin{forest} qtree edges/.style={for tree= parent anchor=north, child anchor=south} [A, grow=north [C, name=C, grow'=north [D, grow=north ] [E, name=t5, grow=north ] ] [B, grow=north ] ] \hspace{0.8cm} [$F$, name=F, grow=north ] %\draw (F.north) -- (C.south); \end{forest} %\end{exe} \end{document} I'd like the nodes F and C to be connected. I don't know why, but if I delete the dollar signs, node F doesn't even appear on my document. Another thing is that I want the forest environment to be embedded in an example environment, but this doesn't work either. Thanks in advance for your help! |
I cannot update Ubuntu 12.10 tried update and upgrade dpkg was interrupted, you must manually run sudo dpkg --configure -a to correct the problem. sorry cannot post image | I was running an upgrade with the apt-get command, and it was taking an exceptionally long time because half way through my ISP hit me in the face with their fair usage policy. After sitting outside & watching the rain for awhile my electronics regained consciousness, so I went back to complete the upgrade and my terminal scolds me with "E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem." The last bit of legible info was all this: Installing (ri/RDoc) documention for (stuff and such) ERROR: Could not find a valid gem 'watobo-0.9.8.724.gem' (>= 0) in any repository rm: cannot remove `watobo-0.9.8.724.gem': No such file or directory Setting up metasploit (4.3.0-bt1) ... Upgrading Pre-Existing Installation... /opt/metasploit/postgresql/scripts/ctl.sh : postgresql (pid 1191) already running prosvc is running metasploit is running [*] [*] Attempting to update the Metasploit Framework... [*] So on it goes for miles, talking about gem caches, rubies, & stuff I wish I had. All up until: A lib/gemcache/ruby/1.9.1/gems/state_machine-1.1.2/gemfiles/active_record-2.1.2.gemfile.lock ...and there it has sat, all night. If I stop it, will I still get the dpkg error (on the off chance that I won't), or if so what do I need to to resume using apt-get commands and its Super Cow Powers? |
please smallcaps bold tex coding provided? | I can't seem to have both the small caps and boldface styles on a line: \huge\sc\bf Hello This will generate bold text, and if the \sc is placed after, it will generate small caps text but not bolded. They seem to override each other, so is there any way to apply them both? |
The wire is at 50hz, and is an aluminum alloy (AAAC 1120). Resistance in the wire is at 0.0897 ohm/km. So for a length of conductor 135km long, the resultant resistance will be 12.1095 ohm. It's AC current at about 220 KV. Other data about the wire can be found . The line will be carrying roughly 15 MW of current. How fast (in any measurement, but in an actual number) would the current move through the wire? I know about electron drift already, what I need to know is how fast it would travel through a wire with those specs, so if a pulse starts/stops how long it takes for this change to reach the other point 135 km downstream. Edit: have checked possible duplicates, and while they do cover the same matter, i'm looking for a number or a fraction. While I know it's a fairly high portion of the speed of light, it's not an actual number. Some say 2/3, some say 1/10, some say 8/10, and when you deal with almost 300000km/s it's a large difference. They all say it depends on the wire, and aluminum alloy wire for large amounts of current is no doubt very different to standard copper. | On a systems level, I understand that as electrons are pushed into a wire, there is a net field and a net electron velocity. And I've read that the net electron drift is slow. But electricity travels through the wire, essentially at c, and I want to understand that mechanism. My apologies if my question is poorly stated, I know bare bones undergraduate quantum theory circa 1990s but it doesn't explain the motion of electricity in detail. Here's my conception, I'm hoping someone will fill in the holes, ha ha. An electron moves into the wire. It's got a kinetic energy. After travelling a short distance, it spontaneously emits a photon, which hits another electron in a valence shell. That electron then presumably does the same. If this conception is simply wrong, please enlighten me. The questions that arise: Presumably at this level, electrons are acting more like waves and less like particles, but is there any classical component in the picture, ie are electrons coming in imparting other electrons with kinetic energy through repulsion, or does it not work that way? If electrons momentarily have energy, then pass it on by a photon, what determines when that photon is emitted, and what frequency it will be? I assume that electrons in this cloud are not limited by any kind of exclusion principal, and that any frequencies are possible? Why should a photon emitted by an electron be in the direction of travel? Conservation of momentum tells me that if an electron is moving, the photon should be emitted in that direction, slowing the electron, but could an electron emit a photon in the opposite direction? If it did, I assume it would somehow have had to absorb energy from elsewhere? That sounds possible by analogy with quantum tunneling. What is the mechanism by which electrons propagating increase the temperature of the material? Are they transmitting energy to the electrons in the valence shell, which tug at the nucleus, do some photons hit the nuclei directly, or is there some other way? Presumably, electricity travels slower than light, because there is some time in each exchange, and some time when electrons are moving at sublight speeds before emitting a photon. By how much is this slower than light, and what is the speed of each interaction? |
I put SQL Server 2012 Standard on a virtual machine (VMWare) which has roughly 98GB of Memory. Now I checked the query below how much memory is taken by SQL Server. Microsoft SQL Server 2012 - 11.0.5058.0 (X64) And see that he ate already 81GB of the memory and the max Memory is set to ~90GB. Using: select (physical_memory_in_use_kb/1024)Memory_usedby_Sqlserver_MB, (locked_page_allocations_kb/1024 )Locked_pages_used_Sqlserver_MB, (total_virtual_address_space_kb/1024 ) VAS from sys. dm_os_process_memory SQL Server 2012 Standard should support only 64GB of memory. Why does my SQL Server eat more than he can? Or is the info incorrect? Any idea? Is that related to a virtual machine using virtual memory? I don't know if balloon driver is activated on VM Host... If you need any more info I will add it. | With SQL Server 2005, you could look at the Task Manager and, at least, get a cursory look at how much memory is allocated to SQL Server. With SQL Server 2008, the Working Set or Commit Size never really goes above 500 MB, even though the SQLServer:Memory Manager/Total Server Memory (KB) perf counter states 16,732,760. Is there a setting where it will actually show the server memory in the Task Manager? Or is it a result of them changing how memory is used in SQL Server |
I understand how generators and iterators work, but I don't see why generators are supposed to be so useful. I saw multiple tutorials that use a prime number finder as an example, however, I always also saw ways how to achieve the same without using a generator (without storing the numbers), for example I usually found things like this: def gen_prim(num): while True: if is_prime(num): # just some function that returns true or false if num is a prime yield num num += 1 for i in gen_prim(1000): if i < 1000: print(i) else: break However, instead of creating a generator in the first place, we could just instead of yielding num, do print(num) inside of gen_prim right away, as we're going to do that later anyways, and can thus remove the for loop. So, as said, I don't understand how generators are beneficial, as to me it seems they just produce more code. I would greatly appreciate an explanation of why they are considered useful and how exactly I can use them that they are beneficial to me, because as you saw, they don't seem to help me very much. | I'm starting to learn Python and I've come across generator functions, those that have a yield statement in them. I want to know what types of problems that these functions are really good at solving. |
I am trying to show the following: Let $\{X_i\}$ be i.i.d with $P(X_1=(-1)^{k}k)=\frac{1}{ck^2log(k)}$ for $k\ge 2$ with $c=\sum_{k}\frac{1}{k^2log(k)}$ a normalizing constant. Show that $\mathbb{E}[|X_1|]\infty$ but there is a non-random $\mu_n$ such that $n^{-1}S_n-\mu_n\rightarrow 0$ in probability. My attempt is the following: $$\mathbb{E}[|X_1|]=\sum_{t=2}^{\infty}tP(|X_1|=t)=\sum_{t>2;t=2k}^{\infty}tP(X_1=t)+\sum_{t>2;t=2k+1}^{\infty}tP(X_1=-t)=\sum_{t=2}^{\infty}\frac{t}{t^2log(t)}=\infty$$ Since $X_1$ is unbounded I need to show the $nP(|X_1|>n)\rightarrow 0$ in order to guarantee existence of $\mu_n$ that is $n=o(P(|X_1|>n))$ Consider $P(|X_1|>n)=\sum_{t>\lfloor n\rfloor}^{\infty}P(|X_1|=t)=\sum_{t>\lfloor n\rfloor}^{\infty}\frac{1}{ct^2log(t)}$ since $\frac{1}{ct^2log(t)}\rightarrow 0$ as $t\rightarrow \infty$ then $\sum_{t>\lfloor n\rfloor}^{\infty}\frac{1}{ct^2log(t)}\rightarrow 0$ as $n\rightarrow \infty$. Since $\sum_{t>\lfloor n\rfloor}^{\infty}\frac{1}{ct^2log(t)}$ goes to zero quicker then n goes to $\infty$ then the desired property holds and the existence is guaranteed. Is this correct or is my approach completely wrong. | Let $X_n$ be iid random variables with $P(X_n=(-1)^kk)=\dfrac{C}{k^2\log k}$ for all $k\geq 2$. Here $C$ is just a constant so that the sum of probabilities is $1$. Find constant $\mu$ such that $S_n/n\to \mu$ in probability where $S_n=\sum_{k=1}^nX_k$. Here $E(X_n)=\infty$. I'm a bit lost after this. In general how does one find constants like this? |
Let $f(z)=\frac{z^{5}}{|z|^4}$ for ($z\neq 0$) and $f(z)=0$ for $z=0$ then $u$ and $v$ satisfy Cauchy-Riemann equations everywhere but $f(z)$ is not differentiable at $z=0$ which means its not analytical because for a function to be analytic it must be differnetiable everywhere. I am confused because my teacher said that if $u$ and $v$ satisfy Cauchy-Riemann equations then $f(z)$ is analytic but this example proves that this is false. Am I misunderstanding something or is my teacher wrong? | It is, of course, one of the first results in basic complex analysis that a holomorphic function satisfies the Cauchy-Riemann equations when considered as a differentiable two-variable real function. I have always seen the converse as: if $f$ is continuously differentiable as a function from $U \subset \mathbb{R}^2$ to $\mathbb{R}^2$ and satisfies the Cauchy-Riemann equations, then it is holomorphic (see e.g. Stein and Shakarchi, or ). Why is the $C^1$ condition necessary? I don't see where this comes in to the proof below. Assume that $u(x,y)$ and $v(x,y)$ are continuously differentiable and satisfy the Cauchy-Riemann equations. Let $h=h_1 + h_2i$. Then \begin{equation*} u(x+h_1, y+h_2) - u(x,y) = \frac{\partial u}{\partial x} h_1 + \frac{\partial u}{\partial y}h_2 + o(|h|) \end{equation*} and \begin{equation*} v(x+h_1, y+h_2) - v(x,y) = \frac{\partial v}{\partial x} h_1 + \frac{\partial v}{\partial y} h_2 + o(|h|). \end{equation*} Multiplying the second equation by $i$ and adding the two together gives \begin{align*} (u+iv)(z+h)-(u+iv)(z) &= \frac{\partial u}{\partial x} h_1 + i \frac{\partial v}{\partial x} h_1 + \frac{\partial u}{\partial y} h_2 + i \frac{\partial v}{\partial y} h_2 + o(|h|)\\\ &= \left( \frac{\partial u}{\partial x} + i \frac{\partial v}{\partial x} \right) (h_1+i h_2) + o(|h|). \end{align*} Now dividing by $h$ gives us the desired result. Does there exist a differentiable but not $C^1$ function $f: U \rightarrow \mathbb{R}^2$ which satisfies the Cauchy-Riemann equations and does NOT correspond to a complex-differentiable function? |
This is a Windows problem, not Notepad++. Please re-open the question. I found the solution though: Clicking the Restore default font settings button does the trick. I'm not sure how it happened but some programs in Windows have text which is too large now. For example : It only happens on some texts and applications, not all. Even Java Swing programs are affected. The display settings font size is still set to the recommended 100% so that's not it: How do I fix my font size problem to what it was before/supposed to be? | Is there any way to change the width or the size of tabs in Notepad++? I usually have many tabs open, and it makes it hard to see all of them at once because I need to press the arrow keys to see which one is where. In other words, notepad++ doesn't resize tabs at all. In a normal browser, tabs are resized according to how many you have. If you have too many, then they are squeezed together. This is exactly what I want to achieve. Is there perhaps an extension that does this for Notepad++? I'd also like to add that I'd rather not use the document switcher. I have the reduce tab size option enabled, but unfortunately it doesn't make it much better! |
Let for the linear operator $A:E\to E$, $A^k=0$, then $A^n=0$. Here $n=dim E$ and $n <k.$ I tried to find the characteristic oolynomial that I think it is the clue, however did nit succeed. Any suggestion? | $A$ is a $n\times n$ matrix such that $ A^m = 0 $ for some positive integer $m$. Show that $A^n = 0$. My attempt: For $n > m$, it's obvious since matrix multiplication is associative. For $n < m$, $A^n\times A^{m-n} = 0$; not sure what to do next. Also I know that $\det A = 0$. |
I have a GSM modem that sends data via UDP (it appears) I have configured it to send all data to my public IP address over the internet but no data is arriving at my end so I need to troubleshoot. I have confirmed that a TCP connection can be made from anywhere on the internet on the same port that the modem is supposed to be communcating on. Im using "Aggsoftware TCP/IP or UDP data logger" to listen for incoming data. Is there software that I can use to test sending of UDP data? | I'm got a video streaming application that runs fine in my office but fails miserably at the customer location. The symptom is that every couple of seconds, I stop receiving UDP packets for 2 seconds, then the stream resumes as if nothing is wrong. I ran at the customer location and it came back excellent. No dropped packets and low latency. The only difference I noticed between our two locations is that ping google.ca times-out at their location but works in mine. How do I test whether the network I am on blocks incoming UDP packets? Is there a way for me to isolate who is dropping the packets? |
I've been trying to use rsync to simply copy all my TIF image files from the current folder onto a 'HR' folder under 'Documents' with no success so far, by the following command: rsync -r *.tif /home/myusername/Documents/HR As I see it the -r option is the one used for recursive copying but said command only copies whatever TIF file there is on the current folder. Could anyone please tell me where I went wrong with it? Suffice to say,said current folder has lots of multilevel subfolders containing hundreds of TIF files. | I am trying to create a directory that will house all and only my PDFs compiled from LaTeX. I like keeping each project in a separate folder, all housed in a big folder called LaTeX. So I tried running: rsync -avn *.pdf ~/LaTeX/ ~/Output/ which should find all the pdfs in ~/LaTeX/ and transfer them to the output folder. This doesn't work. It tells me it's found no matches for "*.pdf". If I leave out this filter, the command lists all the files in all the project folders under LaTeX. So it's a problem with the *.pdf filter. I tried replacing ~/ with the full path to my home directory, but that didn't have an effect. I'm, using zsh. I tried doing the same thing in bash and even with the filter that listed every single file in every subdirectory... What's going on here? Why isn't rsync understanding my pdf only filter? OK. So update: No I'm trying rsync -avn --include="*/" --include="*.pdf" LaTeX/ Output/ And this gives me the whole file list. I guess because everything matches the first pattern... |
I am checking the Belgian rail website for traveling to Lille. I get two options in Lille: Lille Europe and Lille Flandres. What is the difference between these two stations? I suppose location, but is one served by more trains than the other? Do all trains stop in both? Are they completely unrelated meaning some trains go to one, others go to the other? Which one should I pick to Be near to the center? Get transport to the airport? | Lille has two main train stations, Lille Europe and Lille Flanders. (Gare de Marchandises Saint-Saveur is no longer a station, and instead hosts art exhibitions and the like). Lille Europe is the new station on the high speed lines between London / Paris / Brussels, while Lille Flanders is the original station now used for a mixture of local and high speed trains. For some rail journeys, changing trains in Lille is the best option (avoiding having to cross Paris to change trains), and for others it's the only option. Sometimes you get lucky and both trains use the same station in Lille, but not all. For the cases when you find yourself needing to change between Lille Flanders and Lille Europe stations, what's the connection like? Does it take long? Is it outside / inside? Is it a faff with luggage, or is there a step-free route for most of it? Are you best to walk, or take public transport? And a lower concern, is there anything interesting to see of the town during the transfer? |
Many superheros have their origins in/around world war 2 or older events, Wonder woman was a nurse, captain america was a soldier, but other these characters very super powers explain their lack of aging and general fitness. Other characters who have a defined back story, like Batman or the Flash, rely less on real-world dateable events. Magneto on the other hand, in the year 2019, is getting a bit old for his backstory -- which is integral to his character motivations. Having survived the holocaust he wants to prevent the same thing from happening to mutants. Even assuming he were born in the last year of WWII, he'd be 75; more likely at least 80 given he was old enough to remember it. To my knowledge he has no powers that would keep him from aging or showing infirmity, yet he's generally shown as middle aged or slightly older and still very fit. Has any author attempted to explain this away in universe? (Obviously the out of universe explanation is he's recognizable with a relatable story and marvel wants to keep cashing in) | Magneto currently resides with Cyclops on utopia and is barely showing any signs of aging, despite being born in the 1920s. I realize that this is also the case for many other characters in cartoons and comics who aren't portrayed by actors and thus aren't constrained by consistent casting. I know in the X-Men: Evolution cartoon he undergoes some process to heighten his mutant abilities, which also seems to have strengthened him in general, but this is the only instance of his age being reduced or otherwise fortified that I can find. I also know he was supposedly 'de-aged' but it turns out that was merely a clone. How has he aged so gracefully then? |
If I'm using an <a> tag click event to trigger an ajax call, and I don't want the link to physically go anywhere, what is the correct value for the href attribute? Is it '#' or just leave it empty? (I understand the accessibility issues that this brings). | The following are two methods of building a link that has the sole purpose of running JavaScript code. Which is better, in terms of functionality, page load speed, validation purposes, etc.? function myJsFunc() { alert("myJsFunc"); } <a href="#" onclick="myJsFunc();">Run JavaScript Code</a> or function myJsFunc() { alert("myJsFunc"); } <a href="javascript:void(0)" onclick="myJsFunc();">Run JavaScript Code</a> |
Assume that $F[h(\xi);x,y]$ be the inverse of $G[h(\xi);x,y]$ in the sense that the following identity is satisfied: \begin{equation} \int dz F[h(\xi);x,z]G[h(\xi);z,y] \equiv \delta(x-y) \end{equation} for any $h(\xi)$. Then one can obtain: \begin{equation} \dfrac{\delta}{\delta{h(z)}}F[h(\zeta);x,y] = -\int d\xi d\eta F[h(\zeta);x,\xi]\dfrac{\delta G[h(\zeta);\xi,\eta]}{\delta{h(z)}}F[h(\zeta);\eta,y] \end{equation} Question:How can I prove/understand this functional derivative? Note: This functional derivative appears in . [APPENDIX A:(A.7)] | I'm trying to work through a derivation of Hedin's Equations in Effect of Interaction on One-Electron States by Hedin and Lundqvist (1969) and I've come across an identity that is given without much explanation that I'd like to understand. We start with an equation of motion with single particle Green's functions G: $\left[ i\frac{\partial}{\partial t_1} - h(1) - \phi(1) - V_H(1)\right] G(1,2) - i\int v(1^{+},3) \frac{\delta G(1,2)}{\delta \phi(3)} d3 = \delta(1,2)$ where $1=(x_1,t_1)$, $h$ is the one-electron kinetic energy and ion interaction, $\phi$ is a small perturbing field that is set to zero at the end, $V_H$ is the Hartree potential, and $v$ is the Coulomb interaction. They then insert the identity $\frac{\delta G(1,2)}{\delta\phi(3)} = -\int G(1,4) \frac{\delta G^{-1}(4,5)}{\delta\phi(3)} G(5,2) d(4,5)$ which is then used to define the self energy $\Sigma(1,2) = -i \int v(1^+,3) G(1,4)\frac{\delta G^{-1}(4,2)}{\delta\phi(3)} d(3,4)$. I know this identity is related to the definition of the inverse Green's function $ \int G(1,3) G^{-1}(3,2) d(3) = \delta(1,2)$ but I can't figure out how to get from this definition to the identity that is inserted into the equation of motion. Any ideas? Thank you! |
I just took these screenshots: It has said this for a long time now (I now have 12 HP answers, not 9). Why is my tag badge count not updating? I have tried switching to tracking my next priv., and tracking a different tag badge. Nope. | On the "Next tag badge" panel of for C# tag, I see: 92/100 score 88/20 answers But, when I open the "Select your next badge" panel, there's: 97/100 score 90/20 answers I'm not sure which one is correct. But I believe that both displays should show the same counts. The discrepancy is not due to a caching, I've noticed it the first time many weeks ago. For these particular current counts: I have a single C# answer with 3 votes only in the last 5 days, last upvoted 13 hours ago (2015-10-12 19:30:05Z). So it should not cause the 5 votes and 2 answers difference. I believe that the counters on the "Select your next badge" are correct and the counters on the "Next tag badge" are wrong, as I have: Asked 1 non-wiki question with a total score of 6. Gave 90 non-wiki answers with a total score of 97. Today (2015-10-16), the "Next tag badge" got bumped to 97/100. But "Select your next badge" shows 98/100 already. |
I don't have internet during the day and I need to post by email. Is it possible? | If a user is not getting the answers he needs, could I ask him to send me an email or something or pm me in skype? |
We are trying to replace a 20A 250V single outlet that was installed in 1975. We have tried replacing it with a 15A 120V double outlet. When checking our completed work, the outlet tester read that the wires were reversed. We changed the wiring, and the outlet tester still read that the wires were reversed. | I used the above GFCI/RCD (up to 250v) socket tester on the 240v black and red live wire of the US split phase ac power system. When I connect the ground, all indicator lights (3 red) got on indicating "Live/Grd Reverse, Missing GRD" although it is connected properly. What is inside the socket tester? Does it have a live and neutral leg such that it should only be used for ac system with polarity? How about if you use it on the red and black 240v phase to phase? Why would all the indicators light become on (3 red lights)? The following is the specs of it: Specifications: Brand Name: HABOTEST Color: Black Material: Flame Retardant ABS Plug Type: US Voltage: 48V-250V 45-65Hz RCD Test: >30mA (EU/UK Plug) RCD Working Voltage: 220V±20V GFCI Test: >5mA (US Plug) GFCI Working Voltage: 110V±20V Voltage Measurement: 48V~250V / 45~65Hz Accuracy: ±(2.0%+2) Working Environment: 0°C ~ 40°C, 20% ~75%RH Storage Environment: -10°C ~ 50°C, 20% ~80%RH Safety Rating: EN61010-1,-2-030, EN61326-1,CAT II 300V Item Size: 62 * 65 * 55mm / 2.4 * 2.6 * 2.2in Item Weight: UK 64g/2.3oz, EU 59g/2.1oz, US 53g / 1.9oz Package Size: 7.5 * 7.4 * 7.3cm / 3.0 * 2.9 * 2.9in Package Weight: UK 90g/3.2oz, EU 86g/3.0oz, US 79g / 2.8oz |
I've a function called fadeIn and I want to return it until a condition is met. I tried to put an alert in the else line along with clearInterval(myVar), but it just keeps alerting. CSS: * { background-color: black; padding: 0; margin: 0; height: 100%; } #title { background-color: white; height: 50px; } audio { display: none; } #audio-icon { width: 50px; background-color: white; } #focus { background-color: black; margin: auto; width: 100%; height: 700px; border: 5px, solid, grey; border-style: inset; border-radius: 10px; } #text-box { background-color: black; width: 100%; height: 200px; margin-top: 500px; float: left; border: 5px, solid, grey; border-style: inset; border-radius: 10px; } #command-line { background-color: black; width: 100%; height: 50px; margin-top: 150px; float: left; border: 5px, solid, grey; border-style: inset; border-radius: 10px; } #element { opacity: 0.1; } HTML: <audio id="background-audio" controls autoplay="autoplay" loop> <source src="Darkness.mp3" type="audio/mpeg"> </audio> <div id="title"> <img id="audio-icon" src="unmute.png" onclick="mute()"> <img id="element" src="123.png"> </div> <div id="focus"> <div id="text-box"> <div id="command-line"></div> </div> </div> JavaScript: function fadeIn() { var myVar = setInterval(fadeIn, 500); var element = document.getElementById('element'); if (element.style.opacity < 1) { element.style.opacity -= '-0.1'; } else { clearInterval(myVar); } } function mute() { var audio = document.getElementById('background-audio'); var img = document.getElementById('audio-icon'); if (audio.muted) { audio.muted = false; img.src = 'unmute.png'; } else { audio.muted = true; img.src = 'mute.png'; } } document.onload = fadeIn(); UPDATE: I have put the variables outside of the function and all of the sudden my code seems to work correctly. Not sure how this is possible since I have tried this already. My code wouldn't run at all and alert would keep alerting. Anyway thanks for all the help. This was my first question so apart from a few typos and the way I listed my code I don't really know why I get downvoted so any feedback about that is welcome! Here is my current working code: <script> var myVar = setInterval(fadeIn, 500); var element = document.getElementById('element'); function fadeIn() { console.log(element.style.opacity) if (element.style.opacity < 1) { element.style.opacity -= '-0.1'; } else { clearInterval(myVar); } } function mute() { var audio = document.getElementById('background-audio'); var img = document.getElementById('audio-icon'); if (audio.muted) { audio.muted = false; img.src = 'unmute.png'; } else { audio.muted = true; img.src = 'mute.png'; } } document.onload = fadeIn(); </script> | What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally? |
I'm fairly familiar with using Tikz. I've used it to make simple logos before. Now, I'd like to create this diagram, which is a little more complicated: Does anyone have any advice on what the best way to do this would be? I'm aware that it's very easy to use the image file in my output (\includegraphics). However, I'd like to make it in Tikz if possible, for infinite scalability. BTW, the blue is #080f6a. | Is it feasible to convert math in a picture, say written by hand, into LaTeX? For example, I'd deem it faster to write down (de novo) a 10 x 10 matrix with long, complex entries, rather than typing it in LaTeX or MathType. If I then take a picture or scan my writing, how can it be rendered or transformed into LaTeX? |
Is it possible for a player to be sent off for two yellow card offences before the first yellow card has time to be shown? e.g. where the referee plays advantage after the first offence. | If a football player A fouls player B in a manner such that they will receive a yellow card, but the referee plays the advantage rule, and subsequently player A fouls another player, can the referee give him two yellow cards, and hence a red card, one for each foul, or does player A get only the one yellow? |
Let $A, B$ be commutative rings with identity elements and let $\mathfrak{p} \subseteq B$ be a prime ideal. Let $\varphi: A \to B$ be an injective ring homomorphism. I want to show that the induced homomorphism $\varphi_{\mathfrak{p}} : A_{\varphi^{-1}(\mathfrak{p})} \to B_{\mathfrak{p}}$ is also injective. Moreover: Why is the induced morphism of schemes $f: \text{Spec}(B) \to \text{Spec}(A)$ dominant? The motivation of the first question: To show this is sufficient for showing that the induced morphism of sheaves $\mathcal{O}_{\text{Spec}(A)} \to f_{*}\mathcal{O}_{\text{Spec}(B)}$ is injective. | Let $\alpha:A\to B$ be a ring homomorphism, $Q\subset B$ a prime ideal, $P=\alpha^{-1}(Q)\subset A$ a prime ideal. Consider the natural map $\alpha_Q:A_P\to B_Q$ defined by $\alpha_Q(a/b)=\alpha(a)/\alpha(b)$. Suppose that $\alpha$ is injective. Then is $\alpha_Q$ always injective? I think so, but I'm clearly being too dense to prove it! My argument goes as follows. Let $\alpha(a)/\alpha(b)=0$. Then $\exists c \in B\setminus Q$ s.t. $c\alpha(a)=0$. If $B$ is a domain we are done. If not we must exhibit some $d\in A\setminus P$ s.t. $da=0$. Obviously this is true if $c =\alpha(d)$. But I don't see how I have any information to prove this! Am I wrong and this is actually false? If so could someone show me the trivial counterexample I must be missing? Many thanks! |
How can I prove that?I tried to find a solution but I don't know how to do it. | My functional analysis textbook says "The metric space $l^\infty$ is not separable." The metric defined between two sequences $\{a_1,a_2,a_3\dots\}$ and $\{b_1,b_2,b_3,\dots\}$ is $\sup\limits_{i\in\Bbb{N}}|{a_i-b_i}|$. How can this be? Isn't the set of sequences containing complex numbers with rational coefficients the required countable dense subset of $l^\infty$? Thanks in advance! |
I was trying to install playonlinux on ubuntu 15.10 64-bit, so that I could install adobe ps cc. I have already installed wine from the software center, but I got some errors, here I am attaching the snap. Talking about the last few lines in second image, "errors were encountered while processing:" runit git-daemon-run These are the errors I get after I try to install any application on ubuntu. How ca I fix this issue? | I am using 15.04. So I'm working with git and I installed the standard version. I set up the ssh keys and was able to clone one of my repositories to the correct folder. Everything was working great and then I decided it was a good idea to install more packages. I ran sudo apt-get install git-all. I'm looking at error codes now having to deal with upstart. start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused No apport report written because the error message indicates its a followup error from a previous failure. dpkg: error processing package runit (--configure): subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of git-daemon-run: git-daemon-run depends on runit; however: Package runit is not configured yet. dpkg: error processing package git-daemon-run (--configure): dependency problems - leaving unconfigured Errors were encountered while processing: runit git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1) This is what happens when I even update/upgrade my system. At this point all I'm looking to do is be able to install software and update my current software. Is there any way I can potentially reverse this issue or at least correct it? Edit: Thankfully this issue was solved only a day or two after it happened. The accepted answer worked perfectly and took care of my issue |
I am building a big Algo. and I got stuck trying to code a helping algo. I found some good examples in the Interner but all of them are missing a small and important detail: I need to code a methode: combine(int[] numbers, int n) numbers is an array of unique numbers, for example: {1,2,3,4,5,6,7,8,9} and n is the length of the combinations, for example: n=3 -> [1,2,3] or [7,2,5] as simple example of the method: int[] numbers = {1,2,3,4} System.out.println(combine(numbers,2)) the output should look like this: 1,2 1,3 1,4 2,3 2,4 3,4 its very important that redundant does not come out, such as: 1,2 and 2,1 and also not same numbers such as 1,1 or 2,2 the code that I found looks like this: (it does not remove redundant and that is my problem) public static List<int[]> combinations(int n, int[] arr) { List<int[]> list = new ArrayList<>(); // Calculate the number of arrays we should create int numArrays = (int)Math.pow(arr.length, n); // Create each array for(int i = 0; i < numArrays; i++) { list.add(new int[n]); } // Fill up the arrays for(int j = 0; j < n; j++) { // This is the period with which this position changes, i.e. // a period of 5 means the value changes every 5th array int period = (int) Math.pow(arr.length, n - j - 1); for(int i = 0; i < numArrays; i++) { int[] current = list.get(i); // Get the correct item and set it int index = i / period % arr.length; current[j] = arr[index]; } } return list; } and I did call it in main like this: public static void main(String[] args) { int[] current = {1,2,3,4,5,6,7,8,9}; List<int[]> s = combinations(2,current); for(int j = 0; j < s.size(); j++) { System.out.println(((int[])s.get(j))[0] +"," +((int[])s.get(j))[1]); } } and the output looks the same like the one before but with more combinations and alot of redundants how to edit the code above to get the output with out redundants? | I want to write a function that takes an array of letters as an argument and a number of those letters to select. Say you provide an array of 8 letters and want to select 3 letters from that. Then you should get: 8! / ((8 - 3)! * 3!) = 56 Arrays (or words) in return consisting of 3 letters each. |
i have try different solutions from this media but still it does not work for me please help me. function get_category(){ var xmlhttp = new XMLHttpRequest(); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { var ans = document.getElementById("sell_panel"); ans.innerHTML = xmlhttp.responseText; } } xmlhttp.open("GET", "includes/get_category.php", true); xmlhttp.send(); } `$('.item_btn').on('click', function () {// HERE IS MY CLICK EVENT alert("helo"); });` AND MY get_category.PHP FILE IS; <?php include("database.php"); $db = new Database(); $sql = "SELECT DISTINCT category FROM stock"; $result = mysql_query($sql); if($result === FALSE) { die(mysql_error()); // TODO: better error handling } while($cat = mysql_fetch_array($result)){ echo " <div class='item_btn' id='{$cat[0]}'>//HERE IS THE DIV <label>{$cat[0]}</label> </div> "; } ?> I HAVE TRIED delegate() also it did not work for me and i have heard about to trigger my event handler in ajax but i dont know how to do it please help me guys | I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off. This happens on page ready and works just fine. The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound. I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option. |
I’m writing the master thesis, and I’d like to know if the following text would be appropriate or not. Consider the middle paragraph is copy-pasted from the source In this section, I will briefly overview the Lipsum dummy texts and full details can be found in the source [1]. Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum. Bibliography: [1] Source, formatted in APA, IEEE, … | I am writing a project report for my master degree in STEM (U.S.). I have to cite a large paragraph of others' work. This paragraph describes some basic stuff (For example, a duck has two eyes and two legs). I did not change a word in that paragraph. I have already cited this paper at the end of my report. Is there anything else I can do to avoid plagiarism? |
So for whatever reason I was going through looking for questions that had slipped through the retag/migrate net. I found , which clearly didn't belong on SO, and probably would be migration-rejected here due to low quality; however, I can't custom-close-vote (not enough rep), and flags don't have a custom option. I flagged it for migration in the hope that it would be processed correctly. I then came across , and decided to use the same tactic - No, I haven't! (Apologies for the poor freehand-circle quality; the Surface RT is not very conducive to drawing them.) Have I done something wrong and been covertly banned from raising close flags? Is there a new one-outstanding-close-flag limit? Is there a new no-more-close-flags-while-you-have-an-outstanding-migration-flag limit? Is this just a plain old bug? Update: Turns out I flagged it two weeks ago, and the flag was still waiting for review. *facepalm* | After I and flagged some spam on the , for a poorly-understood reason, I went back to one of the questions I'd flagged and opened the flag dialog. There, I saw something of little importance, but of less than perfect... perfection: I had flagged as spam. I had not flagged the question as "not welcome in our community". And, for what it's worth, I had not added a custom flag, so... that part's right. |
What I need to type when I want to summon "equipped" mobs? I want to summon headless zombies(wearing air on their head). So, can you tell me what to type in the chat(after "summon zombie") for each part of the body's equipment, please? Edit:Tell me also on other parts of the body. | I can't figure it out. I can only summon mobs with other mob heads. I've been wanting to summon a cow with a water source block head and name it " Underwater Mission Fail"— Is that possible? |
So I was wondering whether it's possible to downgrade my old Nexus One which is currently on gingerbread back to Froyo. If so, how do I go about this? I don't know much about downgrading on Android, but I think I have to root the device first and then flash a stock ROM. If that's the case, where could I find Android 2.2 ROM for my Nexus One? Any help is appreciated. | I would like to downgrade my Nexus One to 2.2.2, because I've had non-stop problems with Gingerbread. I have the 2.2.2 update from , and going off the , I'm under the assumption that this is doable. So I've gone through the Bootloader -> Recovery -> apply sdcard:update.zip steps, and it fails with the following message: assert failed: file_getprop("/system/build.prop", "ro.build.fingerprint") == "google/passion/passion/mahimahi:2.2.1/FRG83D/75603:user/release-keys" || file_getprop("/system/build.prop", "ro.build.fingerprint") == "google/passion/passion/mahimahi:2.2.2/FRG83D/91102:user/release-keys" E:Error in /tmp/sideload/package.zip (Status 7) Installation aborted. I would guess the OS is checking if I'm on either 2.2.1 (updating from the previous version) or 2.2.2 (reinstalling the target version), is this assumption correct? This begs the question, how do I go from 2.3.6 to 2.2.2? Do I need to factory reset, and apply updates sequentially? |
Code that prints the contents of array randomly, the result recuired is print contents randomly, could do that with Math.Random(); public class Random { public static void main(String args[]) throws Exception { String[] Answers = new String[4]; Answers[0] = "OS"; Answers[1] = "GOOD"; Answers[2] = "CS"; Answers[3] = "Cody"; for(int n=0;n<Answers.length;n++) { System.out.print(Answers); } } } the above code prints [Ljava.lang.String;@1db9742[Ljava.lang.String;@1db9742[Ljava.lang.String;@1db9742[Ljava.lang.String;@1db9742 would want it to print CS,OS,GOOD, CODY or OS,CODY,GOOD,CS and so on | In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the of the array, as defined by Object.toString(): int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray); // prints something like '[I@3343c8b3' But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs: // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5] // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob] |
Given the Lagrangian density for a real scalar field $\mathcal{L}(\phi, \partial_\mu \phi)$, we obtain from Noether's theorem the canonical stress-energy tensor $$ T^{\mu\nu} = \frac{\partial \mathcal{L}}{\partial (\partial_\mu \phi)} \partial_\nu \phi - g^{\mu \nu} \mathcal{L} $$ Can anyone tell me, or provide a (hopefully detailed) reference, why there is always (I think?) a rank $3$ tensor $X^{\lambda \mu \nu}$ such that $$\widetilde{T}^{\mu \nu} = T^{\mu \nu} + \partial_{\lambda} X^{\lambda \mu \nu}$$ is symmetric? I'm fine with assuming $g$ is the Minkowski metric, but I can only find this done in particular cases of $\mathcal{L}$ and no general argument. | What is the correspondence between the conserved canonical energy-momentum tensor, which is $$ T^{\mu\nu}_{can} := \sum_{i=1}^N\frac{\delta\mathcal{L}_{Matter}}{\delta(\partial_\mu f_i)}\partial^\nu f_i - \eta^{\mu\nu}\mathcal{L}$$ (the four conserved Noether currents corresponding to four possible spacetime translations) where $\{f_i\}_{i=1}^N$ are the $N$ matter fields in the theory, and we assume $f_i\mapsto\alpha^\nu\partial_\nu f_i$ for translations, and stress-energy tensor from the Einstein-Hilbert action, which is: $$ T_{\mu\nu}\equiv-\frac{2}{\sqrt{-g}}\frac{\delta\mathcal{L}_{Matter}}{\delta g^{\mu\nu}} $$ In particular, how do you get that the two are equal (are they?) for Minkowski space, for which there is no variation in the metric? |
Could you please help me find how I could put the numbers of the pages on the top of each page as is used in classicthesis? This is my mwe : \documentclass[fontsize=12pt,% twoside=semi,% headings=small,% chapterprefix=true,% listof=flat]% {scrbook} \addtokomafont{pageheadfoot}{\scshape\small}%changed to small caps in headers \usepackage{lipsum} \begin{document} \chapter{A chapter} \lipsum \chapter{Another chapter} \lipsum \end{document} | I want to number my pages in the top corner, left or right - it depends on the side of book, the left page in book should have number on the left side and the right page on the right side. It works now only for one side (right or left). |
Consider the polynomial $P=X^5-X-1\in\Bbb{F}_3[X]$. I want to show that $P$ is irreducible. We can easily check it has no roots, so the only way it could not be irreducible is by being a product of two polynomials of degree $2$ and $3$ respectively. So I determine all the irreducible polynomials of degree $2$ in $\Bbb{F}_3[X]$. These are $$X^2+1;{~~} X^2+X-1 {~~}\text{and}{~~}X^2-X-1.$$ Finally I check using the Euclidean division algorithm that none of those polynomials divides $P$, which concludes the proof. My question is this: is there a more efficient way to do this? I had to first determine all the polynomials of a given degree ($2$) and then apply Euclidean algorithm to each of them. That is quite some work, and we're still considering polynomials of relatively small degree, and fields of small cardinal. I can't imagine applying the same reasoning to determine whether $Q=X^9-X^2-1\in\Bbb{F}_{17}[X]$ is irreducible. So, is there a more efficient method to determine irreducibility, at least in the case of polynomials of small degree over small fields? | Using the affine linearized polynomial $f(x)=x^p-x-b$ is irreducible over $\mathbb{F}_q$ if and only if $\operatorname{Tr}_{\mathbb{F}_q/\mathbb{F}_p} \neq 0$. But here $\mathbb{F}_3$ is not a field extension of $\mathbb{F}_5$. Also we have that: Let $a \in \mathbb{F}_q$ and let $p$ be the characteristic of $\mathbb{F}_q$. Then the trinomial $x^P - x - a$ is irreducible in $\mathbb{F}_q[x]$ if and only if it has no root in $\mathbb{F}_q$. |
I recently installed Ubuntu onto my external hard drive which is fine apart from the fact it will not allow me to search for or connect to wireless networks. My internal hard drive has Windows 7 installed and the wireless works perfectly fine and always has, so I doubt it's a hardware issue. However, the Ethernet is usable as I have a Huawei mobile wifi device and USB cable and can connect to the internet using that, but its not ideal and I wish to be able to connect to my home hub while I'm using Ubuntu. The name of my wired connection is "geometric". I ran the wireless info script and the results are here: I have tried sudo service network-manager restart but that didn't work. Another thread suggested adding the SUSPEND_MODULES line to the config file but that also didn't have any effect. | I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible. What are the steps to install Broadcom wireless drivers for a BCM43xx card? I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc. lspci -vnn | grep Network showed: Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b] iwconfig showed: lo no wireless extensions. eth0 no wireless extensions. NOTE: Answer below is updated every time new information is added and confirmed working. |
So I am trying to install Greyhole onto my Computer to make it into a Home Server. So I run the command 'tar zxf greyhole-0.14.0.tar.gz && rm -f greyhole-0.14.0.tar.gz' but when I run it I get back this message from the terminal 'tar (child): greyhole-0.14.0.tar.gz: Cannot open: No such file or directory tar (child): Error is not recoverable: exiting now tar: Child returned status 2 tar: Error is not recoverable: exiting now' and I do not know how to fix it. If there is someone who installed Greyhole and had this issue could you let me know what you did to fix it. Thank you! | I am not able to extract tar file Command tar -xvfz node_archive.tar.gz khem Error show error tar:z: can't open :No such file or directory tar: Error is not recoverable : Exiting now |
I'm currently trying to create ContentVersion records from Attachment ones but it's giving me the following error: INVALID_STATUS, Documents in a user's private library must always be owned by that user.: [OwnerId] Code: List<Attachment> attLIST = [SELECT Id, Name, Body, BodyLength, ContentType, Description, OwnerId, ParentId, IsPartnerShared FROM Attachment WHERE ParentId = :currentParentID LIMIT 1]; ContentVersion cv = new ContentVersion( Title = attLIST[0].Name.substringBefore('.'), PathOnClient = attLIST[0].Name, VersionData = attLIST[0].Body, IsMajorVersion = true, OwnerId = attLIST[0].OwnerId, ContentLocation = 'S', SharingOption = attLIST[0].IsPartnerShared ? 'A' : 'R', FirstPublishLocationId = attLIST[0].OwnerId ); insert cv; List<ContentDocument> cdLIST = [SELECT Id, Title, LatestPublishedVersionId, FileType, ContentSize FROM ContentDocument ORDER BY CreatedDate DESC]; ContentDocumentLink cdl = new ContentDocumentLink(LinkedEntityId = attLIST[0].ParentId, ContentDocumentId = cdLIST[0].Id, ShareType = 'V'); insert cdl; What am I doing wrong? | I am getting an attachment via a Salesforce email service and in the Email service apex class logic, I query the user object by the email from address and set the ContentVersion owner as the user coming from the Query. I am getting this error while performing this operation. INVALID_STATUS, Documents in a user's private library must always be owned by that user.: [OwnerId] Here is my code : global Messaging.InboundEmailResult handleInboundEmail(Messaging.InboundEmail email, Messaging.InboundEnvelope envelope) { Messaging.InboundEmailResult result = new Messaging.InboundEmailresult(); //Get users for the incoming email address and also community user List<User> lstUsersFromCommunity = [SELECT Id FROM User WHERE Profile.UserLicense.Name = 'Partner Community'; AND Email =: email.fromAddress]; //Process only if the incoming email address is belongs to a valid community user if(lstUsersFromCommunity.size() > 0){ //Get the user from the results list User user = lstUsersFromCommunity.get(0); try{ //Create a list of ContentVersion to store new ContentVersion records List<ContentVersion> lstVersion = new List<ContentVersion>(); //Iterate over the incoming email attachments for (Messaging.Inboundemail.BinaryAttachment binaryAttachment : email.binaryAttachments) { //New ContentVersion record ContentVersion newContentVersion = new ContentVersion(); newContentVersion.versionData = binaryAttachment.body; newContentVersion.OwnerId = user.Id; newContentVersion.ContentLocation = 'S'; newContentVersion.SharingOption = 'A'; newContentVersion.Origin = 'H'; newContentVersion.title = email.subject; newContentVersion.pathOnClient = binaryAttachment.fileName; lstVersion.Add(newContentVersion); } insert lstVersion; }catch(Exception ex){ System.debug('### EXCEPTION : ' + ex.getLineNumber() + ' : ' + ex.getMessage()); } }else{ //No user in for the from email address } return result; } |
I recently got logged out of chat somehow, and now I am locked out. When I try to log into my it asks me to log in. On the global chat login page, it says, "If automatic login fails, please visit the GlobalAuth test & help page to check for common problems." I visit that page and it says that everything is fine. It suggests that I log out of my main account, which I do, and that I remove all my stackexchange.com cookies, which I do. I can log into my , and my , but going to a chat site still asks me to log in and fails. I am running Firefox 16.0.1 and MacOS X 10.5.8 and use a Google OpenID. This has all worked before. Note: I can log into my . | Janrain has , one of the many OpenID providers. MyOpenID will not be available starting February 1, 2014. (An hinted at the same but did not set a date for end of service.) This decision was made by Janrain, and Stack Exchange did not have any part in it. You can still use myOpenID to log in to Stack Exchange, but be aware that any outages in the myOpenID service will mean that you are unable to log in to Stack Exchange until Janrain fixes it – which may take several days, or weeks, or never. After February 1, you will no longer be able to use myOpenID to log in to Stack Exchange. Stack Exchange will not be able to answer any questions about why myOpenID is down or when it will be working again. If you do not have any other login credentials on your account by February 1, you will be locked out, and Stack Exchange will be unlikely to help you recover your account. To avoid getting locked out of your Stack Exchange account, we strongly suggest that anyone using myOpenID as their primary (or even backup) login add a new login method to their Stack Exchange account. We're also going to remove the "myOpenID" button from the sign-up/login page soon, in order to discourage new users from signing up using myOpenID. Here's how to add a new login to your account. You must be logged into your account when you begin. (This information is also available .) Open up your user profile page (by clicking on your login name at the top of the screen) and click the "my logins" link above the bio box on the right hand side. You should see a list of all of your logins. To add a new login, click "add more logins..." at the bottom of the box. Choose the new login from the list and follow the steps to confirm. If you choose, you can remove your myOpenID login by clicking the same "my logins" link, then clicking "remove" next to myOpenID. If you are adding a Stack Exchange OpenID, you will receive a confirmation email. You must click the link in the email to confirm your email address before the Stack Exchange OpenID will show up under "my logins". Please make sure that you are already logged into your account when you click the confirmation link; otherwise, you will create a new account that needs to be merged with your old one. If you encounter any trouble adding logins, or accidentally create a separate account that you would like merged, please fill out our . |
What was the first US television series in which the main cast were mostly african american? | I was watching MeTV the other day, which is a fantastic station chock-full of old-time TV shows. In one sitting I saw episodes of Superman, Batman, Wonder Woman, The Rifleman and Star Trek (TOS). So it got me thinking... None of these shows has many (if any) black actors. And now I'm curious as to which TV show was the first to feature a predominantly black cast. Anyone know? I'm thinking back to What's Happening, Good Times, The Jeffersons... But were there any before then? |
Lately the Stack Exchange android app (v 1.0.58 on an android 4.4 phone and a 5.0 tablet) won't render some posts. Both questions and answers are affected. I can see votes and comments but the post content is an empty white box. : | Note: the bug has returned in version 1.0.89 in a somewhat different form. See: This possible bug report is similar to the bug in that was deemed not-reproducible. I can reproduce something similar with more recent app & Android versions. App Version: 1.0.34 (original report; is still present in 1.0.38, 1.0.42, 1.0.58) Android Version: 4.4 (up to 4.4.4) Device: Motorola Droid Maxx In the examples below, you can see some blank answer bodies. These are on different sites, and represent answers with both edited and non-edited text. In the first example, I clicked on the top answer tab to get to the answers, and in the second example I clicked on the bottom "View n Answers" button. (Trying to be a good little tester!) Because I've seen this blank-answer-body intermittently over the past couple weeks (before the May 7 update), my process to test was just to go to the first site I frequent and then systematically click through the question list until I found a question with answers in which at least one answer was blank. For all three sites shown below, it was within the first 5 or 7 questions sorted by newest. Please note that I have seen many questions with several answers, none of which were blank. It is truly intermittent. Example blank answer body at Workplace.SE: Example blank answer body at Programmers.SE: Example blank answer body at UX.SE: And now here's the kicker, which makes me think this is some sort of content-loading latency issue rather than a rendering issue: I returned to the left-side menu, selected the User Experience site, picked the same question as above, and then clicked the top answer tab to view answers again, and lo and behold the text is there: I then went back to the other questions with blank answers, shown above, and the answer bodies were no longer blank. I am happy to go through more tests/paths and do screenshots if it is helpful. The same bug also appears in question bodies. |
Need to find a preg_match pattern for the phone numbers below (a mixture of more than one, have kept all in one var), am getting the one preceded with 'Tel,Toll Free' but not the one on new line..looking for some help..or sugestion preg_match_all('/((.*)|\s)?\s*?\:\s*?([0-9 A-Z a-z \-\+\.\,\/\(\)(Ext))]*)/i $phAr="Tel: 813-227-4500(+787 45 55 56) Tel : 002-6598-6554 (+98-214-214) (509) 878 9856 658 Tel: 888 (408) 546-777 Ext 1122 or 1133 Tel: 888 (408) 546-000 (TollFree) Toll Free: 1-125-PYS-PYS(145-547-554-45) Tel: +88 555-988 (408)/(999) Toll: 1-125-PYS-4YOU (Mr. Toran) Toll Free: 1-125-PYS-PYS +9999-888-66655 (258) Tel: 813-227-4500 Ext 1254 / 8525 Phone : (855) 834-7487 +1-9999-888-66655-PYS-PYS (+98-987-658498) 99-408-546-099 (Mr. Reigh O) Address1 Part1 8760 North Address2. Address2 00 9999 "; | I'm trying to put together a comprehensive regex to validate phone numbers. Ideally it would handle international formats, but it must handle US formats, including the following: 1-234-567-8901 1-234-567-8901 x1234 1-234-567-8901 ext1234 1 (234) 567-8901 1.234.567.8901 1/234/567/8901 12345678901 I'll answer with my current attempt, but I'm hoping somebody has something better and/or more elegant. |
I want to cite an article from a spanish author having the character í in his name. MWE: \documentclass{scrreprt} \usepackage[utf8]{inputenc} \usepackage{filecontents} \begin{filecontents}{bib1.bib} @article{test, author = {Garc{\'{\i}}a, S.}, journal = {J. Phys.}, number = {7}, pages = {535}, title = {Some interesting title}, volume = {13}, year = {1987} } \end{filecontents} \usepackage[ bibstyle=phys, articletitle=false, backend=biber ]{biblatex} \addbibresource{bib1.bib} \begin{document} \cite{test}. Test: Garc{\'{\i}}a. \printbibliography \end{document} This produces an error: ./main.tex:31: Package inputenc Error: Unicode char ÃÅ (U+301) (inputenc) not set up for use with LaTeX., although in the normal text the name appears correct. How can I fix this? | Under biber 2.1 my biblatex produces input encoding errors. The same procedures worked smoothly under biblatex 2.9a/biber 1.9, now that I upgraded to biblatex 3.0/biber 2.1 I get the following message when pdflatex runs after biber: Package inputenc Error: Unicode char \u8:╠ü not set up for use with LaTeX. Here is a minimum working example: \documentclass{article} \usepackage{lmodern} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[backend=biber]{biblatex} \bibliography{test.bib} \usepackage{filecontents} \begin{filecontents}{test.bib} @article{rodr, author = {Rodr{\'{\i}}guez, A}, year = {1999} } \end{filecontents} \begin{document} Rodr\'{\i}guez \textcite{rodr} \printbibliography \end{document} Any help appreciated! |
I want to assign a variable when if statement is true. What's wrong with this assignment? b = 1 if 3 > 2 File "<stdin>", line 1 b = 1 if 3 > 2 ^ SyntaxError: invalid syntax | If Python does not have a ternary conditional operator, is it possible to simulate one using other language constructs? |
I have a set {0, 1, 2, 3, 4, 5}. What properties do I need to show to prove that it is a group under addition modulo 6? Any examples would be greatly appreciated! | The set $Z_n = \{ 0, 1, . . . , n-1 \}$ for $n ≥ 1$ is a group under addition modulo n. For any $j > 0$ in $Z_n$, the inverse of $j$ is $n - j$. This group is usually referred to as the group of integers modulo n. My understanding of this is as following, please let me know if I have gotten the main idea. Let's pick $Z_3$ as an example. Then the members of this group is $0,1,2$ let $j=2$ then $n-j=3-2=1$ it says the inverse of $j$ is $n - j$, by definition, an inverse in a group is such ab=identity. And here the identity is 0 under addition. therefore, 2+1=3 and 3 mod 3 =0 which is the identity. This applies to any n in $Z_n$ So, it satisfies as a group? |
My friend had an exam but he didn't come because he was sick. Then he needs to pass the exam even he wasn't there. What is the verb or phrase which describes what he needs to do? ("making-up" the missing works here?) In addition, in Europe, in some of the universities if you didn't come then you have to pay to the university on the missing class and then you have to go with the receipt to the professor of the missed class and you have to represent the topic that you missed and show him that you studied by yourself, and he asks question about the topic in order to ensure that this student controls in the topic. Is it called "making up" classes or it is something else? | I'm looking for one word which describes what a student who missed classes needs to do in order to complete his missing. For example if he missed biology class he needs to seat with the teacher and study this missed class together with her and then he get the mark for this missed class. Someone -who isn't native English speaker- told me that it's called "rework". But I looked for it in some dictionaries (such as ) and I didn't find such definition. : "SCHEDULE of reworks of missed classes" |
Prove that $g \in o(f)$ implies $f + g \in \Theta(f)$. I'm pretty stuck on this one. I know that there is a constant $c_2$ such that $f \le c_2 (f+g)$, but I'm not sure how to prove that there exists a constant $c_1$ such that $c_1 (f+g) \le f$. If I can prove that then I can say that $f + g \in \Theta(f)$. Anyone have some suggestions? | I know that big O is used to describe the upper bound of a function, so doesn't this mean that if the upper bounds f and g are the same, they are the same function? If this is the case, then we can say that f ∈ Θ(g) because if that were not the case, then the two upper bounds would not be the same and thus one would out grow the other. Is this correct? |
I posted a bounty on on May 27, intending to reward it to the person who had a highly upvoted answer that was accepted on May 19. The reason I chose from those available was One or more of the answers is exemplary and worthy of an additional bounty. When the time was up, I forgot to actually give the user the bounty. The system didn't automatically give it, even though it was the only answer there when I started the bounty and there are no deleted answers that were ever posted to the question. I propose that, if the exemplary answer reward bounty reason is chosen and there was only one answer when the bounty was added and none were posted during it, the bounty should automatically be given in full to the pre-existing answer. | I am not asking... ... to for reward-type bounties. ... for the the winning answer, either. My request is this: When a user sets a bounty to reward an existing answer, existing answers should be eligible for auto-award of the bounty. It makes no sense to deny eligibility to the answers that the user explicitly wanted to reward. An Example: Math.SE currently has three 500-point bounties set by a departed user, with the stated reason "reward existing answer". They are set to questions with outstanding and very thorough answers. However, those answers will not receive bounty now, because the originating account has been deleted. The bounties are still there, owned by Community and subject to auto-award rules. |
How to render an image like this with black lines ? Image taken from the following faceboock page: | For an architectural visualization, I would like to use MakeHuman models, but: Only get them to render white with a black outline (on reflection surface too, if possible). Interact with light like normal human bodies in the scene (cast shadows, etc). I can do the outline in freestyle, but any in-Cycles solution would be appreciated (OSL?) |
Good evening, I confess, I'm a begineer. I've just heard about Linux and wanted to try it on my just turned Windows 10 PC. wubi and Windows 10 Yet, I met a first issue with wubi which told me that the Ubuntu 14.04.3 installer cannot download the metalink and therefore the issue. It also gave me a reference to a log file I don't know how to reach! c:\users\antoine\appdata\local\temp\wubi-14.04-rev286.log I am aware that having windows 10 may prevent me to use wubi. The second issue I met was when I tried to install it manually. Live CD After having downloaded ubuntu on a CD, I accessed to the boot interface in order to change the booting. After removing the safe-I-don't-know-what I only had three choices of booting IVP4 IVP6 Windows No Cd booting. Live key I also have a liveLinux key a friend of mine gave me to help me instal Linux My questions are: Is there any chance to boot to my CD in order to really install Linux on my device? Is there any way I can install Ubuntu thanks to the wubi? How can install Linux thanks to this key that doesn't have any .iso file? Thanks for considering my worries! | I would like to see a full how-to guide on how to install Ubuntu. |
I know that there's but it doesn't have any real answers despite having been viewed 12,400 times, and the fact that it's been closed. With that in mind... Why in the world is 1366x768 resolution a real thing? It has an aspect ratio of 683:384, which is the weirdest thing I've ever heard of while living in a 16:9 world. All screens and resolutions I've been familiar with have been 16:9 aspect ratio. My screen, 1920x1080, is 16:9. The 720p that I'm familiar with is 1280x720, also 16:9. 4K that I'm familiar with, 3840x2160, is also 16:9. Yet 1366x768 is 683:384, a seemingly wild break from the standard. I know there are plenty of other resolutions all over the place, but 1366x768 seems to dominate most of the mid priced laptop world and also seems unique to the laptop world. Why don't laptops use 1280x720 or something else as a standard? | Most displays get advertised with either 16:9 or 4:3 display ratio. However, if you compare the resolution with the display ratio, it's most often neither of both. For example, the resolution of my notebook display is 1366x768. But 1366/768 = 683/384 != 688/387 = 16/9 Another common resolution is 1920/1200 = 8/5 But for some resolutions it's correct: 1024/768 = 4/3 800/600 = 4/3 Is there a technical reason / user experience reason for this? Why do displays have other ratios than what they get advertised? (I assume that every pixel is a perfect square. Is this assumption wrong?) |
I have a VB.net console application with command line arguments. Like ("-Arg1=Value1 -Arg2=Value2 -Arg3="Value 3") this i'm passing arguments from project properties -> Debug ->Command line arguments. My plan is to run this console application from batch(.bat) file. I can able to run like this. @echo off D:\Project\Bin\Debug\abc.exe %* -Arg1=Value1 -Arg2=Value2 -Arg3="Value 3" But my expectation is while running console application it need to ask values for -Arg1, -Arg2 & -Arg3 I need to pass values at run time. | I need to pass an ID and a password to a batch file at the time of running rather than hardcoding them into the file. Here's what the command line looks like: test.cmd admin P@55w0rd > test-log.txt |
The question: The definite article 'the' has many usages. However, I cannot quite understand one usage, that is, 'used to mark a noun as being used generically'. What does it mean by 'noun being used generically'? Can anyone please shed some light on this and set some examples. An example for this use is 'The dog is a quadruped.' How can I distinguish if the author is expressing a generic noun/idea instead of specifying something in front of 'the'? Readers Note: Readers interested in this question might like this question here: - That question is about using generic noun phrases with nationalities. | In English, generic reference takes three possible forms: A. Cats are cute. B. A cat is cute. C. The cat is cute. But the names of nationalities seem to me to make an exception to this rule. As far as I know, when referring to all the members of a nation, you can only use the C version: The Italians are musical, or The French are posh, or The British are cold. Why is it that in this case only C is considered grammatically correct? If all the Italians, or all the French, or all the British are musical, posh, or cold, why can't we also say: A. *Italians are... // *French are... // *British are... or B. *An Italian is... // *A French is... // *A British is... ? |
I love the "random" input in the shader editor; it makes it so easy to randomize duplicated objects by changing the color and offsetting textures and all that. It would be crazy useful to be able to do a similar thing with shapekeys, so the geometry can vary as well. I can control the value with a driver, and I tried the method in , but that changes the shapekey value on every frame (as happens with every "random" solution I've tried so far), which means in an animation it's a jittery mess (he suggests "muting" the drivers to fix this, but the scene still runs super slowly, since I think it's still running the randomizer for every value for every frame, even if you can't see it). So my question is, how can I give that shapekey a random static value? I figure something like multiplying the object's ID by a wacky number or something, but I just can't figure it out. I feel embarrassed posting this, because I feel like this is a fairly basic thing that's probably answered elsewhere, but I've been searching obsessively for a couple days and just keep finding the same few threads over and over, so hopefully someone here knows?? Thanks in advance! | My question is related to my previous asked one: I have about 300 shapekeys and want to set the random value for all of them . How to do it using scripting? |
I am building a simple inverting operational amplifier circuit where I am using a chip with dual amplifier. I am only using one of the two amplifiers. What should I do to the unused amplifier's input pins? Should I leave them floating or is there a good way to sort of terminate them. | I am using a dual op-amp package in a circuit, however I only need to use one. Is there anyway to disable the other op-amp so it doesn't inject electrical noise in my circuitboard? I think grounding the positive input and setting the op-amp into unity gain might be best, but I am not certain. |
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