Hartshorne's weird definition of right derived functors and prop. III 2.6

There is something very weird with the way Hartshorne defines right derived functors.     Hartshorne p 204 Let $\mathfrak A$ be an abelian category with enough injectives, and let $F \colon \mathfrak A \to \mathfrak B$ be a covariant left exact functor. Then we construct the right derived functors $R^iF, i ≥ 0$, of $F$ as follows. For each object $A$ of $\mathfrak A$, choose once and for all an injective resolution $I^.$ of $A$. Then we define $R^iF(A) = h^i(F(I^.))$   With Prop 1.2A. Hartshorne claims that one can also compute the right exact functor $R^iF$ with a resolution $J^i$ that is acyclic for F.  But then, in prop. 2.6 (and similarly in prop. 8.4) Hartshorne states what was already true by definition: that the derived functors of $\Gamma(X,^.)$ coincide with the cohomology functors $H^i(X,^.)$. The proof goes around a circle to show the obvious fact that an injective resolution is equivalent to itself. Namely, that every injective is flasque (2.4), and flasques are acyclic (2.5), so by 1.2A. (above) we can use this very injective resolution(!).  What do we need to go around like that?


I've a polygon layer for parcels in a landscape protection area and a point layer, contains zoological data (e.g species, entities, etc.).  How can I make a statics for each polygon, contains the list of observed species, the count of observations by species and the sum of entities by species?  I would like to make it in QGIS with shapefiles or spatialite database.


Why can't I see the leaves of a tree through a transparent object?

I created a transparent glass object and I am able to see every mesh with the exception of leaves. The tree in the picture includes hair particles on a vertex group with a png image of a branch. You can see in the image how the trunk appears but not the leaves.


Prove that $r_1^2+r_2^2+r_3^2+r^2=16R^2-a^2-b^2-c^2$  Where  r denotes the respective in-radius and R the circum radius  a,b,c are the sides of the triangle    I have tried using the   $\frac{\Delta}{(s-a)\dots}$  But I get a fraction with a irreducible $\frac{denominator}{numerator}$.


Find the least Positive Integer Satisfying $1+\frac{1}{2}+\frac{1}{3}+\cdots+\frac{1}{n} \ge 4$  My try:  I actually applied a Brute Force taking:  $$\int \frac{dx}{x} \ge 4$$ Then we get: $$\ln x \ge 4$$ Hence $$x \ge e^4$$  So approximately $n=55$  Is there any better approach?


I have a site that is a website/online store for the company. The main goal of the site is to sell the company's product.   In looking to markup the site I am stuck as to what type I should choose.    would work but that is really broad.  is a bit more specific but still really broad. I thought about using  but my concern with using that one is it falls under Local Business. This business is online only, no local store front.   What type should I choose? Is it okay to use Store for an online business even if it doesn't have a local store front?  Also, I've considered using productontology to add an additionalType but there really isn't another type that I can think of.


Noise instead of shadows around my windows

I'm getting noise around my windows in ubuntu 16.04. I have a fairly normal installation with nvidia graphics card. I don't remember what led to the noise-shadows, but I guess it occured after some apt-get upgrade. Any suggestions. I seem to have both the nvidia-367 and nvidia-375 installed. Below is a screenshot of the problem.


Length of time before reconsidering feature requests

So there's a feature request (I'm not the OP) which has recently been tagged status-declined.  I was/am highly in favor of the request.  Now I'm depressed.  I will probably drown my sorrows tonight in a case of dark English ale (nothing like the old world).  This particular feature-request had 72 upvotes on it and the reason given for declining was not all that great (IMHO).  How long do we wait (realistically) before asking for a highly-popular feature request which was declined to be reconsidered?  (ok, to save you some forensic time the feature in question is , but this is really just in general)


Solve the equation $x^3 + 117y^3 = 5$ over the integers.   I have tried solving this. It is clear that one of $x$ or $y$ must be negative. $117$ seemed a strange number. So I found out that $117 = 125 - 8 = 5^3 - 2^3$. I don't know if this is useful but still I'm adding it. So the equation becomes:  $$x^3 + (5y)^3 - (2y)^3 = 5$$  I don't know how to proceed further. I need some hints. Any help would be appreciated.


I am using Ubuntu as my main OS and windows 10 is my secondary OS. I have a 500gb hdd.i want to create a new partition or resize my main Ubuntu partition.  How can I do it? Gparted partition don't give me access to resize my main partition.


The total number of solutions (real) of equation: $2^x+3^x+4^x-5^x=0 ?$  I have no idea how to solve this problem. Can someone point me in the right direction?


How can I choose which OS grub will reboot me into—before I reboot?

LILO had a simple feature that allowed one to select the boot menu entry that should be used on the next reboot while in Linux, thus one could select the OS to be booted into on shutdown and didn't had to wait till the computer rebooted to the boot menu and select the next entry manually.   For Grub that feature has existed as unofficial patch as well.  This was quite some years ago. Has that feature made it into mainline Grub in the meantime? Is it available under Ubuntu and is there any way to integrate it with the GUI (i.e. have not only a "Reboot" entry, but a "Reboot into Windows" entry in the shutdown menu)?


Why does adding more terms into a linear model always increase the r-squared value?

Many statistics textbooks state that adding more terms into a linear model always reduces the sum of squares and in turn increases the r-squared value. This has led to the use of the adjusted r-squared. But is it possible that adding a term into a linear model reduces the sum of squares by zero and in turns keep the r squared value exactly the same?


Downloading Wine from the Ubuntu Software Center

In the Ubuntu Software Center, I attempted to download the application Wine. However, it reported that there is not a program called wine in my current software sources. I also tried to download it in terminal, and it read:  Reading package lists... Done Building Dependency tree Reading state information... Done Package wine is not available, but referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source.   I followed the instructions from the website  for both the command line and ppa repository.  Is there another way to get this application?


How to have comments in IntelliSense for function in Visual Studio?

In Visual Studio and C#, when using a built in function such as ToString(), IntelliSense shows a yellow box explaining what it does.       How can I have that for functions and properties I write?


I would like an option on Meta communities to reference tags from different sites, similar to the distinction between [tag:] and [meta-tag:].  To keep things standardized, cross-site tags could use the same naming-format as .   [so-tag:java] →  [su-tag:microsoft-excel] →  [gaming-tag:gaming-history] →      Questions where cross-site tags would be helpful


How to get players to be curious and ask questions?

I have recently noticed that my players don't really try to find out much about the world and story beyond the direct "what do we see?"  I want to have them interact more with their environment and actually explore the reasons behind things without me leading them by the nose. "Why are these monsters working together?"  "What are the villains trying to accomplish?" How do I get my players to be curious and ask those questions that start the gears of imagination like Who, What, Where, When, Why, and How?   These kinds of questions can really bring a world to life and add SO much depth to a story but they just don't ask and if I tell them without them asking the game drags on and they begin to feel like I'm monologuing.


Multiple HNQ widgets don't work simultaneously

Having two or more widgets, I am facing a problem where only the last updated instance of a widget is clickable.  I can refresh any widget with the refresh button, not open SE app by tapping the question.   Can be simulated by refreshing one widget and clicking the question on the second one. The SE app will not open.   Happens on various versions of Android (4.4, 5, 6.0.1) and various launchers, so it's not only a problem with my device


Why can we use the following statement when we mean future events?     What time do you get there?   Or should we rather say:     What time will you get there?   Is there a difference?


What is the best way to take pictures of a document on an LCD screen?

Getting records from the courthouse. They charge $1/page to print which is utterly insane but will let you discreetly take pictures of the computer screen instead.   I have my iPhone and the pictures are usually readable but there are always lines or rgb dots that show up. Is there a technique or anything you’d recommend to take better pictures?  And yes, I’ve already looked into uploading documents from the computer itself. The computer is on a network whitelist. It can access the court website and nothing else. Also it’s run on a vm on top of a basic windows pc. So it’s not an option to have a flash drive.   Here’s an example of a picture I’ve taken.


I live in Chapel Hill, North Carolina, and recently started seeing a bunch of these little guys in my house. They're about 1/8" long (estimate), with brown/black zigzag stripes; it's possible they're babies, but over the last two weeks their size has remained consistent so this seems unlikely.


How to nail focus for DSLR astrophotography?

I've been doing a bit of astrophotography and the problem that I almost always have is nailing focus.  I'll manually focus on a bright star or the moon (which hopefully isn't an option!) by magnifying on live view, leave the lens on manual focus, and then rotate the camera to the target.  My problems happen two fold:   Evenly greatly magnified on the live view screen, there's very little difference between in focus and slightly out of focus of a bring point light source.  It's extremely difficult to tell in camera if its right, but painfully obvious once on the computer after the exposure. I think sometimes the focus ring gets bumped while moving the camera to the target.  So my focus ends up way off.   What are techniques or methods to help here?  I've seen some reference to some sort of diffraction mask that could help, but don't know anything about it.  My particular DSLR doesn't tether to a laptop, so computer aided focus is out for me (but it may be worth mentioning in general for a wider audience with similar issues).


Can I use Class.newInstance() with constructor arguments?

I would like to use Class.newInstance() but the class I am instantiating does not have a nullary constructor. Therefore I need to be able to pass in constructor arguments. Is there a way to do this?


example of a nonempty subset is closed under scalar multiplication but not a subspace

Could anyone provide an example of a nonempty subset $U$ of $R^2$ such that $U$ is closed under scalar multiplication, but $U$ is not a subspace of $R^2$


What is best way to install ubuntu alongside windows 7 ?

I read many paper and I am just utterly confused . Some says don't use first option in Ubuntu install type (install Ubuntu alongside them) and you must use last option ( something else) . Dell Inc says : If You want use something else . You must make partition with free space and use as Ex2 . The other says : You must shrink volume windows drive and install Ubuntu use as Ex3. What i must do finally ? If i make partition with my free space what is happen . what major problems have I encountered if i change my partition ( from windows to Linux )  ? _Thanks_


How can I stop windows re-positioning after waking from sleep?

I put my multi-monitor system to sleep when it's not in use. After I wake it up, all windows are repositioned to a different screen. The closest pattern I can think of is that the windows there were on the main screen switch to a the second screen. It looks like it disconnects the main screen before it goes to sleep which in turn switches all the windows to the 2nd or 3rd screen.   Edit: Here's the video card I'm using --> SAPPHIRE FleX 100322FLEX Radeon HD 6450


What is covariance in plain language and how is it linked to the terms dependence, correlation and variance-covariance structure with respect to repeated-measures designs?


Moving large website to new CMS - URL changes

I was wondering if you have any tips on the following situation.  I'm going to move a large website to a new Content Management System (CMS), here are some details on the site:   online news magazine with roughly 3,000 articles domain age: 10 years online in the current form since May 2010 indexed pages: ~10.000 percent of search engine traffic: under 10%    Unfortunately a custom-tailored CMS was used for the site. The performance, reliability and SEO capabilites have been really bad, so we are moving to a new and proven open source CMS.  All the articles will be kept as they are, but the URL structure as well as the structure of the HTML templates will be changed.  What I wanted to do now is to actually create 301 redirects for all articles from the old to the new schema, i.e:   Old: www.example.com/en/html/news/detail/title-of-the-article/ New: www.example.com/category/title-of-article.html   Is this a proven way to do something like this? If not, can you recommend a way that has worked for you?


Why can I cast pointers of unrelated classes without error?

I've been experimenting with pointers and written the following code:  #include <iostream>  using std::cout;  struct A {     int a;     char b;     A(){ a = 4; } };  struct B {     int c;     B(){ c = 5; } };  A *a = new A; B *b = new B;  int main() {      a = (A*)b;      cout << a -> a; //5 }   Why B* can be converted to A*? Can any pointer be converted to any other pointer?


How find that limit $\lim_{x\to 0}\frac{\sin\left(x\sin\frac{1}x\right)}{x\sin\frac{1}x}$? Its $\lim_{x\to 0}\frac{\sin\left(x\sin\frac{1}x\right)}{x\sin\frac{1}x}=1$?


How can I get the correct offset between UTC and local times for a date that is before or after DST?

I currently use the following to get a local datetime from a UTC datetime:  SET @offset = DateDiff(minute, GetUTCDate(), GetDate()) SET @localDateTime = DateAdd(minute, @offset, @utcDateTime)   My problem is that if daylight savings time occurs between GetUTCDate() and @utcDateTime, the @localDateTime ends up being an hour off.  Is there an easy way to convert from utc to local time for a date that is not the current date?  I'm using SQL Server 2005


Italicizing Variables in SI unit commands

As many other answers have elucidated, the correct way to typeset SI units is with the SI command from siunitx. However, if the value being described is a variable (for example, x metres), doing  $\SI[parse-numbers=false]{x}{\m}$   in math mode will produce "x m" rather than the correct "x m", with an italicized x.   I've attempted to rectify this through toying with the settings of sisetup as per the CTAN documentation for siunitx, but so far I can't find anything to enable this behavior.  Any help in this regard would be appreciated.


Some malware in PdfCreator forces now my Chrome to Bing

How do I get rid of it? I already put Google back as default search engine in settings, completely deleted Bing from that list, and even removed Chrome and reinstalled it - it still refers to Bing.  I can't understand why PdfCreator is recommended despite the amount of malware that's in there.


Can the decision to admit a PhD student be made by a single professor?

Many professors say on their websites not to email them because they cannot make admission decisions alone, but rather it is the decision of a whole committee. However, my undergraduate advisor said there is nothing stopping a single professor from admitting a student if they see fit. Is this true? And if so, how often does it happen?


Words with different meanings in American and British English

This is similar to , but not quite the same.  There are quite a few words which have totally different meanings in American and British English and which are likely to cause confusion when heard by non-local speakers.  What are they?  We are looking for the same word with different meanings (for example jumper), and not words which are different between the two dialects (for example truck and lorry).


Hover and Click action on same object on touch devices

I am building a timeline widget which has 2 interactions on web.  Hover to see a particular duration's details like duration, start time, assigned name. Click to edit details of the timeline  However, the primary use of the timeline widget is on a tablet (touch device). What could be some ways to achieve these interactions on a touch device?


Is it true that the "i before e" rule is vastly untrue?

After reading questions like , and searching for the rule on Google, I happened upon the following image:    This claims that only 44 out of the 967 English words with E and I next to each other are ordered as according to the rule "I before E except after C, or when sounding like A as in neighbor and weigh". Is it true that ~95% of such words break the popular rule?


Can Business Visa/schengen to austria be used to travel to other EU countries for personal trips

I am applying for a multi-entry business visa/schengen for austria and would be spending the bulk of my time in vienna. Since, I dont have any meetings over the weekends,  is it possible for me to visit other EU nations as a tourist using the same Visa


Can't take a proper screenshot with shutter

I'm running Fedora 25 and I need to take a few particular screen captures so I've read that shutter is a great tool for that. Sadly I am unable to use it for some reason. Whenever I try to take a screenshot this is the result:


REVISIT: Make links posted by users open in a new window

Orginal:    It would be nice if in this modern era, Stack Exchange links open in a new tab.  I know that this was voted upon back in 2009, but the times they are a changing and that was six years ago. Several users have discussed this morning that there would be serious advantage in having the Stack Exchange platform do this by default.     It is understood that a userscript could do this, but we prefer a SE internal solution over a browser-script implementation, so for purposes of this revisited discussion we consider that an incomplete solution. Additionally, right click is an insufficient answer; likewise not all users have middle mouse buttons and many use mobile devices.   Thank you for your reasoned consideration of this request and revisiting the topic in a more modern era.


Why a hashtable does not maintain order of insertion?

If hash table is an array of linked-list elements and hash code is index of the element in the array then why hash table does not maintain the order of insertion ??


How to get Windows 8 boot menu in a Windows 8-Ubuntu dual boot?

I have a dual-booted Windows 8-Ubuntu 13.04 system. As usual, by default, the Ubuntu grub menu comes up as soon as we boot. Similar questions have been asked before, and the reply to each of them was Grub Customiser and EasyBCD. My problem is that as soon as I restart my system, the changes in EasyBCD installer get reverted. Please provide me with a solution to this.  This is my boot-menu as in EasyBCD:    Now I go to the boot menu, set priority for Windows 8 the highest and in BCD deployment hit 'Write MBR'. Yet, when I restart, no changes take place and it reverts back to the same order.


I read that a choice set for the rational equivalence relation on a set whose outer measure is positive must necessarily be uncountable. I am having trouble seeing why this is true and was hoping someone could explain this to me. I thought that it would have to have the same cardinality as $\mathbb{Q}$, which is countable.


Find integer $n$ for which $n$ divide $2ⁿ+1$

Find integer $n$ for which $n$ divide $2^n +1$.


Distribution of $1/\sqrt{X}$ when $X$ is a gamma variate

It is a question about finding the posterior parameters. $X$ follows $\text{Gamma}(a,b)$ ----(Prior) $y \vert x$ follows $\text{normal}(\mu,1/x)$  ----- (likelihood), that is variance $(\sigma^2) = 1/x$ The posterior distribution of $X$ is $\text{gamma}( a+n/2, b+(1/2)\sum(x_i-\mu)^2 )$ and of $1/x$ (variance) is $\text{invgamma}( a+n/2, b+(1/2)\sum(x_i-\mu)^2) $, it is the same except the change in the distributions. I tried to solve for the posterior distribution of $1/(x^{1/2})$ but I am unable to find the value of the beta parameter, I got the alpha parameter to be $(2a)$ which I highly doubt to be right.


MySQL database lost all data without any action

I made an application for taxi service with PHP and MySQL. And I use PDO for connecting. I setup an admin panel and I wrote a delete query for delete unwanted price records according to its priceid. But nowadays I lost all price data(Table become empty) sometimes without any action from Admin. Please check my delete query page code below. Thank you for your time.  ob_start(); include 'inc/database.php'; include 'inc/header.php';  if (isset($_GET['getid'])) {     $getId = $user -> cleaninput($_GET['getid']); } else {     header("Location:prices.php"); }  if (!empty($getId) && is_numeric($getId)) {     $adData = $DB_con->prepare("DELETE FROM price_data WHERE price_ID=".$getId." LIMIT 1");     $adData -> execute();     header("Location:prices.php"); } else {     header("Location:prices.php"); }


Windows XP/7 Disabling Users Accounts via. CMD

How can I disable a user account from the command line?  In Windows XP or 7.


Cannot enter phpmyadmin as root (MySQL 5.7)

I'm using Ubuntu desktop 16.04 (upgraded from 15.10).  I had installed phpmyadmin from by apt-get install phpmyadmin. It works if I go to localhost/phpmyadmin but I cannot log into it as root.  I have searched a lot for it. I have found many sources in which they suggest to alter /etc/phpmyadmin/config.inc.php and replace the user and password with 'root' and '' (empty for password). But my config.inc.php is different from theirs. For example in my file, there is no line for user and password and it seems it gets it automatically from another file which is /etc/phpmyadmin/config-db.php. Despite this, I have changed the user and password in that file, but now I get this error:  #1698 - Access denied for user 'root'@'localhost'   What I should do?    Phpmyadmin Version: 4.5.4.1deb2ubuntu1 mysql  Ver 14.14 Distrib 5.7.12, for Linux (x86_64) using  EditLine wrapper


In-universe explanation for single line of planetary entry/departure in Star Wars

Why are planetary blockades confined to a single point of a planet instead of being sphere shell shaped around the planet? (I know, it would take an awful lot of spaceships.)  Also, when a rebel ship wants to escape from a planet and there is a single star destroyer hovering in the atmosphere (or some more of them further up, like in the Empire Strikes Back) how come it's not a viable maneuver to fly low altitude for a couple of hundred kilometers horizontally (they would be out of the single-point blockade), then make a vertical dash upwards?


Moving Windows licence to another laptop

I have an old laptop (Lenovo e530), which came witn Windows 7 preinstalled. My new laptop arrived with Windows 10 preinstalled (Lenovo e550). I would like to put Windows 7 on my new laptop, too. Can I somehow "move" the Win 7 licence from an old laptop to an new one? Or do I already have a right to install all previous versions of Windows, once I have Windows 10 on it?  None of laptops has any stickers with serial numbers.


A book about travelling to hell and cutting worlds with a knife

I am looking for the title of a book, actually a series (probably a trilogy).  I just have a few memories - I read it 20+ years ago but the book is contemporary. The few things I remember:   the two main characters (boy and girl) come from different worlds which are copies one of each other - one of them being dystopian (if I recall correctly) one of the characters (the boy I think) can move from world to world by "cutting a hole" in thin air with a knife they travel at some point (by the end of the series) to Hell when they need to do something to save the worlds   The end is       sad. The two characters fall in love but for some reason they cannot cross the world borders anymore (this is a decision they make for the good of the worlds) and they "meet" on a bench which is in both worlds and imagine the other one being on his/her bench as well.


They seemed a nice couple.  They seemed to be a nice couple.  They seemed like a nice couple.   Are they all correct?


I am learning some discrete mathematics and stuck on following problem : Let $G$ be a graph with $100$ vertices prove/disprove that there are two vertices with same degree. I know that for a given vertex  $v$ there are $99$ choices for a neighbor of this vertex hence degree  ${\rm deg}_{G}(V) \le 99$ But after this I don't know how should I proceed ?


Windows explorer displaying wrong free space

I have a 1TB* external HDD which comes out at 931GB total space on windows explorer (run as admin).  When I look at free space it lists only 183GB free with 747GB used. However, there is not this much used space. When using WinDirStat (run as admin) this drive only uses 472GB of space.  I have cleared the shadowstorage down to the latest shadowstorage using DiskCleanup which increased the free space to the 183GB free. Now I can't think of anything else  that could be causing this 275GB discrepancy.   I had used this external drive on an old laptop, could there be an issue with that?   Thanks for any advice.


Is ArcSDE no longer needed at ArcGIS 10.1?

Through my frustration of not finding the post-installation wizard with ArcSDE 10.1 and being unsuccessful with the command line tool to start an SDE service on our SDE databases, I found I was able to access the databases and copy/past/add features/delete features/etc. all through direct connections to our SQL Server 2012 machine. This was WITHOUT ArcSDE running.   So... The question is, why do I need to go through the trouble of trying to get the SDE services to run if I can manage our databases through the Desktop tools? I was even able to create an enterprise geodatabase and verified that all of the necessary business tables were created. I have even recreated all our map services in ArcGIS Server 10.1 with direct connect and the web editing is perfectly working.   Perhaps I'm missing something...  UPDATE:  As indicated in the  topic:     "The recommended method to access enterprise geodatabases is to   connect directly from ArcGIS clients. If you only use direct   connections to your geodatabase, you do not have to install the ArcSDE   application server."   If you need to edit settings in the ArcSDE system tables, though, you should still install the command line tools included with the application server. I don't think editing system tables directly through SQL is supported technically.


Why does factoring eliminate a hole in the limit?

$$\lim _{x\rightarrow 5}\frac{x^2-25}{x-5}  = \lim_{x\rightarrow 5} (x+5)$$  I understand that to evaluate a limit that has a zero ("hole") in the denominator we have to factor and cancel terms, and that the original limit is equal to the new and simplified limit. I understand how to do this procedurally, but I'd like to know why this works. I've only been told the methodology of expanding the $x^2-25$ into $(x-5)(x+5)$, but I don't just want to understand the methodology which my teacher tells me to "just memorize", I really want to know what's going on. I've read about factoring in abstract algebra, and about irreducible polynomials (just an example...), and I'd like to get a bigger picture of the abstract algebra in order to see why we factor the limit and why the simplified is equal to the original if it's missing the $(x-5)$, which has been cancelled. I don't want to just memorize things, I would really like to understand, but I've been told that this is "just how we do it" and that I should "practice to just memorize the procedure." I really want to understand this in abstract algebra terms, please elaborate. Thank you very much.


Is there a countable basis for the finite complement topology on the natural numbers?

I have the following question on a worksheet: Consider the finite complement topology τf on N. Does this topology have a countable base? If so give one such base and if not prove your claim.  Been trying to solve this for several hours but I have got nowhere. I think that there is no countable basis because it seems like to construct a basis you would need to take the entire topology, but I have no idea if that's right or how to show that.   Thanks


How to change colors for different boards in Trello.com?

I have started using Trello.com for task management, but I really want to be able to customize the colors on different boards.   Is there any way to do this? Is it a possibility now or a possible future enhancement?


Drawing a TikZ arc specifying the center

The TiKz command for an arc:  \draw (0,0) arc (-30:30:2) ;   Draws an arc that starts at (0,0), and would be the part of the circle from -30 degrees to +30 degrees of radius 2.    It is very hard to place these arc sometimes.  This is the symbol i want to draw:    (This represents an eye and needs more detail).  I want to draw the arc as _part of a circle with center at where the < meets, but I have to currently fudge the start location of the arc so it properly crosses the < (and it's not even exact).  If I could do a circle from -45 to +45 degrees CENTERED at the <, then that would be much easier.


I have been told numerous times that magnetic force do no work at all but I have some trouble digesting this fact. Now suppose we have two straight wire with some current, they certainly can feel force which may be repulsive or attractive depending upon  current direction, can magnetic force do work? We also have magnetic potential energy defined to $U = -\vec{\mu} \cdot \vec{B}$ which suggests magnetic field can store energy and hence do some kind of work.


After Windows 10 upgrade I can no longer access BIOS

I posted a question recently regarding my Windows 10 upgrade which ended up with a black screen and cursor.   I reverted back to Windows 8.1 using the "Revert to previous build" option in recovery, and all seems fine, except that Virtualisation is disabled.  I tried to open BIOS settings but it just boots into Windows. I've tried the usual F2 key and Shift F2, all the other F keys, tried pressing B and Shift+B but no luck.  I tried pressing the Lenovo key on the laptop when it is powered down, which shows a menu to either boot into BIOS, recovery, or show boot menu. I choose BIOS and it just boots into Windows.  I tried going into advanced startup options from Windows (Shift+Restart) and choosing "UEFI FIRMWARE SETTINGS" but it just reboots back into Windows.  Before the Windows 10 upgrade it was working perfectly.  Lenovo G580 laptop - Core i3 with Intel 4000 graphics. 8GB of RAM and a Crucial MX100 512GB SSD (replaced the original hard drive with this SSD).


Time keeps changing between BIOS/WIndows 7/Ubuntu 14.04

When I boot into Windows 7, the time maybe for example set to 3:04 pm.  The real time being 11:04 am.  Then I reboot and go into Ubuntu and the time is set to 7:04 am.  With the same date in both.  I go into BIOS and Windows syncs it with the time it believes it is so it'll be set to 3:04 pm.  I've tried changing them all to the right time.  Turning off online sync with both.  And disabling UTC in ubuntu with command      $sudo hwclock --localtime nothing has worked.


A group $G$ with $G'$ abelian and every abelian normal subgroup finite

Let $G$ be a group such that  $G'$ abelian  and any abelian normal subgroup of $G$ is  finite. Show that $G$ is finite.


How do I activate the editing box at bottom of "Tools" section?

When I add a new item (sphere, cube etc) the lower left hand editing box is no longer activated....it is clouded over and unresponsive. For example: I add a UV Sphere but can no longer change the segments, rings, size etc. It was working in the past which makes me wonder if I have inadvertently turned it off....I have closed and reopened Blender but cannot rectify this issue.


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.


Backstory I have a Radeon RX 570 and decided to try out Blender and 3D modelling in general. But after about 2 months I started getting some strange graphical bugs. I did manage to fix a couple of them but apparently blender doesn't like AMD Users. Then I got the wireframe issue. Problem Wireframe viewpoint comes up with this now  and I have yet to fix it. Also for Cycles, It can't even render on the viewpoint and if I dare to render it as an image, my whole PC freezes up.  What I've tried For the wireframe viewpoint strangely breaking I've tried...  Reinstalling Blender to an older version Reinstalling Blender and install a portable install Going through each setting Updated any possible driver and software  For Cycles I've tried...  Changing Cycles rendering device to each possible selection Reinstalling Blender again  Each solution I've tried hasn't fixed anything


I want to make a racing game.Can I have licensed cars without paying for licenses?

My idea was something similar to rFactor, but very easy to mod. There will be a step by step tutorial.  If I or somebody from the developers make the mods and publish them, do I still need licensing? Now it's just an idea, but I plan to make at least 1000-1500 cars from at least 150 manufacturers, and that would cost a fortune. A lot of the cars would be converted from other games like Forza or GT6 and others modeled by my team.


Why can't the wave function and it's derivative be zero at the same point?

This was discussed before proving the node theorem.


How does word co-occurrence let two words from the same topic link together in LDA topic model?

The essence of LDA is word co-occurrence. I want to know why? and does word co-occurrence mean two words appear together in a certain document or just appear in the documents collection together?   Thank you all in advance.


Notification that ‘someone might be watching what you browse’

I got a notification on my iPhone. The notification reads     Someone might be watching what you browse. Follow 3 steps to encrypt your web traffic and change your IP address.   What does this mean?


How do I use target selectors to put player names in chat?

I want to know how to use target selectors such as @p and @r to display a person's gamertag in chat. I've tried to use /tellraw @a {"rawtext":[{"text":"@p"}]} but it just puts @p in chat, not any player names. Could anyone tell me how to get the selector to work?


Suppose $Pr$ is non-atomic that is $Pr(A)$ implies the existence of $B$ with $B\subset A$ such that $0<Pr(B)<Pr(A) $ and $A\in\mathcal{F}$ with $Pr(A)>0$. (a)show that for every $\epsilon>0$, we have $B\subset A$ such that $0<Pr(B)<\epsilon$. (b)Prove that if $0<a<Pr(A)$ then there exists $B\subset A$ such that $Pr(B)=a$.  Here is a hint: fix $\epsilon_n \to 0$ and define inductively numbers $x_n$ and sets $G\in \mathcal{F}$ with $H_0=\emptyset$, $H_n=\cup_{k<n} G_k$, $x_n=\sup\{Pr(G): G\subset A\setminus H_n, Pr(H_n\cup G)\leq a\}$ and $G_n\subset A\setminus H_n$ such that $Pr(H_n\cup G_n)\leq a$ and $Pr(G_n)\geq (1-\epsilon_n)x_n$. Let $B=\cup_{k} G_k$.


I have an if statement the check if all item is selected or not  (Android )  if(region_id == null && City == SelectAll && Distric == SelectAll && itemid== SelectAll){            // DO something  }else{ if(City == SelectAll && Distric == SelectAll && itemid== SelectAll){            // DO something           }else{       if(Distric == SelectAll && itemid == SelectAll)){        // DO something           }     }//end else }//end else   My issue that if dos not working


Is there a PHP function to find out the name of the caller function in a given function?


I understand I can declare a variable with the final keyword as below...  private final List<User> userList = [SELECT Id FROM User];   ... That will generate an array that, when supplied with a value, can't be changed. I'd like to do the same thing, only using a Map.  I've tried:  private final Map<Id, User> userList = [SELECT Id FROM User];   But I can an error arround trying to supply a List<> type to a Map<>, which I understand. Additionally I've tried:  private final Map<Id, User> mapUserIdToUser {   get {     if (mapUserIdToUser == null) {       mapUserIdToUser = new Map<Id, User>();       for (User user : [SELECT Id FROM User]) {         mapUserIdToUser.put(user.Id, user);       }     }      return mapUserIdToUser;   } }   But then I get the following error:     Methods are final by default, Use virtual to declare methods that can be overriden   Ideally I'd like to do something as short and sweet as the first line of code I supplied at the top, so really I'm looking at the cleanest way possible to declare a Map<Id, SObject> using the final keyword as once this variable has been supplied with values, it won't change.  Edit  I may be misunderstanding something pretty simple, but given the error I know I could just remove final and write something like below:  private final Map<Id, User> mapUserIdToUser {   get {     if (mapUserIdToUser == null) {     [...]   But would this act as final and disallow any changes to the variable?


How to reset default permissions for /etc?

By mistake I have made permission changes for /etc. Now it's giving me the following error message:  bash: /etc/bash.bashrc: Permission denied   I have no name!@chandan-Inspiron-5520:~$ sudo /etc/init.d/apache2 restart   sudo: unable to stat /etc/sudoers: Permission denied   sudo: no valid sudoers sources found, quitting   sudo: unable to initialize policy plugin


Why does `last` show '{' and '|' in the TTY field?

We recently set up a new FreeBSD 7.2 machine on March 11. When looking at last, we noticed some funny characters for the TTY field.   What do these characters mean? Note that at this time, the sysadmin was battling with NTP.  # last |grep date date             {                         Fri Mar 10 17:26 date             |                         Fri Mar 10 15:26 date             {                         Fri Mar 10 15:26 date             |                         Fri Mar 10 03:14 date             {                         Fri Mar 10 03:11 date             |                         Sat Mar 11 15:22 date             {                         Sat Mar 11 15:21 date             |                         Sat Mar 11 09:20   And according to man last, I can specify the tty using -t tty:  # last -t { date             {                         Fri Mar 10 17:26 date             {                         Fri Mar 10 15:26 date             {                         Fri Mar 10 03:11 date             {                         Sat Mar 11 15:21


Evaluating this integral : $ \int \frac {1-7\cos^2x} {\sin^7x \cos^2x} dx $

The question :  $$ \int \frac {1-7\cos^2x} {\sin^7x \cos^2x} dx $$  I tried dividing by $\cos^2 x$ and splitting the fraction.  That turned out to be complicated(Atleast for me!)  How do I proceed now?


What is the plastic tubing that DIP's come in

I'm looking to protect some old vintage MOS chips that I own and I don't want this to sound like a stupid question, but I cannot find the name of the plastic tubing that DIP chips can be purchased in.  I've looked up things like "dip chip tube" or "chip plastic cover" but to no avail.  I have actually purchased some old 8-bit CPU's (all DIP's) that came in this kind of tubing that I'm looking for the others and it conforms to its shape.    Does anybody know what these are called and if they are available to buy empty?


Why mass of nucleus decreases after binding of it's components (protons and neutrons)?

Nucleus mass should be equal to sum of mass of protons and neutrons, but after binding of these particles, its mass is reduced. Why? Due to reduced mass of protons or neurons? Then what's the purpose of calculated mass?


Are there any links for cyanogenmod 11 for moto g android 4.4.4? If there are then please suggest me the one which is stable,equipped with the theme engine and is under 100mb.


many Servers of SQL server 2012 needs mirroring

I have two SQL server 2012 instances and I want to configure mirroring between the 2 servers with database.  My questions are:  How can it automatically change host of one if the other one was dropped ?  Is the performance of mirroring is acceptable and is there another way to make one as host and other is backup then if the main server was dropped the other works automatically better than mirroring?


Who is responsible for text mistakes in a print project?

I am a graphic designer and my project was to design and print a cocktail catalog. Everything worked fine till the client realized, when I delivered the printed catalogs, that a cocktail΄s description which was given to me was wrong.  The thing is, I sent many presented files of the work and was asking to check that everything was correct before printing the catalog and that because he made a lot of changes till the end of the desired layout.  I understand that it is also my fault, but isn't the client also responsible for this mistake?


Abelianization of free group is the free abelian group

How does one prove that if $X$ is a set, then the abelianization of the free group $FX$ on $X$ is the free abelian group on $X$?


In notification panel, I have a notification that says "Instal/update Google Play Services" (or so).  How can I solve this problem?


In school we are taught the vowels: A, E, I, O, U, and sometimes Y.    got me thinking about when the letter Y is considered to be a vowel.  I understand (perhaps incorrectly) that in words like bicycle and why it is a vowel. What about the word voyeur (as mentioned in the XKCD alt-text)?   If I've got this backwards, and Y is almost always a vowel, how can I tell when it is a consonant? Thinking back, I don't think my education ever covered the difference between them, we just memorized which letters were which.


How to write a test case to verify EINTR returned by sem_wait function in linux

I have just written the below routine to handle the EINTR error. The routine is given below,  while((s = sem_wait(&w4compl)) == -1) {         if (errno == EINTR)         {                 perror("call interrupted by sig. handler\n");                 continue;         }         else                 printf("Other Error Generated\n"); }   SO, here i am not able to see the print "call interrupted by sig. handler\n" statement. How can test this so that it will print the same(How can i execute the part of if (errno == EINTR)).


What is the microscopic picture for warm air rising?

The usual explanation for warm fluids rising past cooler ones is that the warmer fluid has a lower density.  I'm trying to understand what this looks like at a molecular scale.  The density seems to be a large-scale phenomenon, and I don't understand how it can affect whether a particular molecule rises or falls.  Consider a cylinder of fluid that is being heated at the bottom.  The molecules at the bottom have a higher average energy.  How does this result in the tendency of the warmer molecules at the bottom to move upwards past the cooler ones?


Can a textbox be enabled after a certain value from a picklist is selected

I am having a picklist field which has 3 values 1.Web, 2.Mail, 3.Other.If i select other then the text must be editiable. If i select web or mail then the textbox must in uneditiable mode. Kindly tell how to do this.Im using PE


Qgis2Web - Why are exported labels style not displaying correctly as what has just been set?

I am using qgis2web with QGIS3.0 to make web map. The problems I encountered were:  Label styles not exported correctly. (e.g. color changed, background disappeared after export etc.) Zoom level - I set the Label Rendering based on scale-dependent-visibility. It displayed well in QGIS edit panel. However, it just did not want to work correctly after I exported the map into web map.  Just wondering if there is any bug in QGIS/ qgis2web.js or it was because I did not adjust some settings correctly? This is an example: picture(1) what I desire to see (in QGIS edit panel)  picture(2) faulty exported webmap: (result)  Scales, color, text of label background style are all wrong!


Is Cthulhu the being that chases Rick & Morty in the opening sequence?

In every opening sequence so far on Rick & Morty, no matter the season, we see at the end a scene where they flee in their spaceship from a Cthulhu-like creature, while Summer is holding which seems to be a spawn of the creature. Can we state if this creature is, in fact, Cthulhu? Is there enough evidence to accept or refuse the possibility?


Is SO's programmers site a better place for advanced questions

Two questions I asked received some downvotes on Stack Overflow.   Has anyone encountered random script errors on comment lines in IE8?   Does object literal notation containing functions execute faster than plain functions?   Question one is not a poll, it asks if this is a known problem.  Question two is a question about code performance that has a technical answer not open to debate, I just don't know it.    Questions I would not ask on SO:    3) Is a verbose programming style an issue when compression, minification and obfuscation are available? 4) Can someone provide a list of available obfuscation tools?  Those involve opinion, discussion, and (as I just learned) lists. Would these questions also be voted down or rejected on Programmers.stackexchange.com or is that a more appropriate venue?  Related to this, is Programmers  the appropriate place for subjective and discussion oriented questions instead of using Stack Overflow?


Is it acceptable to nest parentheses (for example, if I (meaning myself) write like this)?


Attributive or Possessive noun: the Dell Company's staff. or the Dell Company staff?

In the following is it better to use a possessive noun with an apostrophe or an attributive noun without an apostrophe?     The following list details the assumptions that have been made in   conjunction with the Dell Company’s staff.   Or      The following list details the assumptions that have been made in   conjunction with the Dell Company staff.   Assume Company is the name of a company, such as Dell.


Why Javascript Object value is changing incase of keys in object but not variables?

I am new to JS , I am trying to execute the following code and log the out put  var name ="xyz"; var age =10; var location ={office:"US",home:"CA"};  function callFn(name,age, location){     name = "abc";     age =20 ;     location['office']="new office location"; } callFn(name, age, location); console.log(name, age, location['office']);   The output is "xyz", 10 , "new office location";  Why the name , age values are not chaning but key values inside object are changing ? IN other languges like java it will assign new values to name and age also


In your code, when you open the FileMp3Reader, uses the word Action and then placed inside by using a Lambda expression, a method.  What does the keyword Action? Inside the file.Create method what is being done?  var mp3Path = @"C:\Users\ronnie\Desktop\mp3\dotnetrocks_0717_alan_dahl_imagethink.mp3"; int splitLength = 120;   var mp3Dir = Path.GetDirectoryName(mp3Path); var mp3File = Path.GetFileName(mp3Path); var splitDir = Path.Combine(mp3Dir,Path.GetFileNameWithoutExtension(mp3Path)); Directory.CreateDirectory(splitDir);  int splitI = 0; int secsOffset = 0;  using (var reader = new Mp3FileReader(mp3Path)) {        FileStream writer = null;           Action createWriter = new Action(() => {         writer = File.Create(Path.Combine(splitDir,Path.ChangeExtension(mp3File,(++splitI).ToString("D4") + ".mp3")));     });      Mp3Frame frame;     while ((frame = reader.ReadNextFrame()) != null)     {                    if (writer == null) createWriter();          if ((int)reader.CurrentTime.TotalSeconds - secsOffset >= splitLength)         {                 writer.Dispose();             createWriter();             secsOffset = (int)reader.CurrentTime.TotalSeconds;                       }          writer.Write(frame.RawData, 0, frame.RawData.Length);     }      if(writer != null) writer.Dispose(); }


Characteristic polynomial of unique matrix

Calculate the characteristic polynomial of $\begin{bmatrix}0 & 0 & 0 & ... & 0 &a_0 \\-1 & 0 & 0 & ... & 0 & a_1 \\ 0 & -1 & 0 & ... & 0 & a_2 \\ ... & ... & ... & ... & ... & ...\\ 0 & 0 & 0 & ... & -1 & a_{n-1}\end{bmatrix}$  So we need to calculate the determinant of $\begin{bmatrix}-\lambda & 0 & 0 & ... & 0 &a_0 \\-1 & -\lambda & 0 & ... & 0 & a_1 \\ 0 & -1 & -\lambda & ... & 0 & a_2 \\ ... & ... & ... & ... & ... & ...\\ 0 & 0 & 0 & ... & -1 & a_{n-1}-\lambda\end{bmatrix}$  I solved $det(\begin{bmatrix}-\lambda & a_0 \\ -1 & a_1-\lambda\end{bmatrix})=(-\lambda (a_1 - \lambda))+a_0=\lambda^2-a_1\lambda+a_0$.    This leads me to believe that the determinant I am trying to find is: $\lambda^n-a_{n-1}\lambda^{n-1}+a_{n-2}\lambda^{n-2}-...+(-1)^na_0$, but I am struggling to prove this theory.


Function in an app that gives alert message when somenone updates list?

I have build an app to get list items etc. Now I want to put a function in it that gives alert message when someone adds,removes or changes something in list.  Is it possible?


How do I create a master workbook in excel?

In powerpoint we have something called a master slide.  I want the same idea for excel.  I want to create a template that I can work on with formulas and I want it to update all children files.  Example: I have a budget template.  This template has a budget listing all required equipments and their cost for a project.  We then have a formula that calculates the total cost of all equipment. I want to update only the template file with equipment and formulas, but I want the actual files (children) to contain the costs (because they might be different costs for different locations, but the rest of the budget and its formulas are shared).  Its pretty much exactly what a master slide in powerpoint is, if you've ever used that you should understand what I'm trying to do pretty easily.  One master file to store formulas, and a bunch of children files that store the data to be accessed by those formulas.  This way if a formula needs to be changed, the templates is adjusted and all other files update accordingly.  Any ideas?  I'd prefer not to have to use VB, and I'd also like a solution that works for both mac and windows.  Found  question but no answers.  I've already created a template, but that doesn't seem to update the other files when I modify it.


How to get a correct reference for shared counters of amsthm and algorithm2e

I tried to have the same counter for the AMS and algorithm2e algorithm-environment with   \usepackage{aliascnt} \makeatletter \let\c@algocf\relax \makeatother \newaliascnt{algocf}{thm}   as described here .  Here is my MWE code. It is created with Lyx, as this is what I use for my thesis.  %% LyX 2.1.4 created this file.  For more info, see http://www.lyx.org/. %% Do not edit unless you really know what you are doing. \documentclass[english]{article} \usepackage[T1]{fontenc} \usepackage[latin9]{inputenc} \usepackage{amsmath} \usepackage{amsthm}  \makeatletter %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands. \theoremstyle{plain} \newtheorem{thm}{\protect\theoremname}   \theoremstyle{plain}   \newtheorem{lyxalgorithm}[thm]{\protect\algorithmname}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands. % algorithms \usepackage[linesnumbered,algoruled,boxed,lined,english]{algorithm2e} \usepackage{aliascnt} \makeatletter \let\c@algocf\relax % drop existing counter \makeatother \newaliascnt{algocf}{thm} \makeatother  \usepackage{babel}   \providecommand{\algorithmname}{Algorithm} \providecommand{\theoremname}{Theorem}  \begin{document}  \begin{lyxalgorithm} \label{alg1} Do stuff. \end{lyxalgorithm} \begin{algorithm}[H]  \label{alg2} Do other stuff. \caption{$\leftarrow$ Prints the correct number 2} \end{algorithm} \begin{lyxalgorithm} \label{alg:alg3} Just be! \end{lyxalgorithm}  Here is a reference to Algorithm \ref{alg1}, Algorithm \ref{alg2} and Algorithm \ref{alg:alg3}.     \end{document}   How do I make \ref{alg2} print the correct number 2 instead of 1?


(Last Jedi spoilers ahead, if you haven't seen the movie, please don't read on.)  So, fridge logic moment for me:      If Vice Admiral Holdo had told Poe Dameron about the plan to just hold on long enough to make a covert run to Krait, then Poe wouldn't have felt the need to send Finn and Rose on their little side-trip, and the code-breaker wouldn't have overheard anything nor sold them out, and the First Order would've had no reason to notice the cloaked ships.   I do understand that there's a lesson in there about following orders, even if said orders come from a pretty face in a pretty dress, but that's kind of an out-of-universe reason. What was Holdo's reasoning? Surely she knew enough about Poe to realize that treating him like a mushroom1 would not result in anything good.  1 "kept in the dark and fed shit"


How to know if connection is made to a server using alias or not?

Is there a way to know if the connection to a host is made via an alias or using the direct host name itself? This is in Linux.  Basically I want to find out what are the connections made to my DB server host using the direct host name itself (and not an alias)  Thanks SK


Curves with constant curvature and constant torsion

Describe all curves in $\mathbb{R}^3$ which have constant curvature $κ > 0$ and constant torsion $τ$.   Any ideas what we can do to describe all such curves?   Do we have to use the formulas of the curvature and of the torsion?


Mysterious -2 on SO due to post removed which was never posted

I have been awarded with .  But i cannot find answer which i have posted and got removed.(because i never posted answer there )  Note: I don't give answer in that tag's too. Still i have been awarded with .  Neither i have Up-voted nor Down-voted any answer/question on that page .  Can anybody explain why that -2 is awarded to me .  See My


Why is this argument about light speed not true?

Long ago I was watching a scientific video about light speed. At one point, the person said to imagine the following scenario:  You are on a train going from the Solar System to the Alpha Centauri system. The supposed train is going at almost light speed, and you are on top of it. While you are on top of the train, you move forward one step in the direction in which the train is moving. Are you going faster than light speed?  The guy in the video said that the answer is no. When I watched the video I had no idea what the explanation meant because I wasn't into physics at all.   I also can't find the video, but I am curious as to why a scenario like this would be not possible (excluding the limitations of technology, and other flaws in the scenario which have nothing to do with speed.) So, why isn't this possible? :)


How to change the default location of the screen shot?

I use Command + Shift + 4 + Space to screen shot.  But you know the default place of the screen shot is Desktop.  So, how can I change the default location? I want to the location to be a custom document folder, not desktop.


Create polygons convex hull with arc basic

I have a bunch of polygons to make from points that need to be more precise than the min bounding box of closest rectangle or circle but don't have an advanced license. Does anybody have a workaround for this? I'm using ArcMap 10.2.2.


Cannot login (login loop), I tried multiple solutions. + no space left

I use Ubuntu 18.04 LTS with Xfce4. I have a very low-end computer and the storage size is very low, only 60GB. I almost stay at a few 100MB from the limit. But now, my computer lagged so I forced to reboot, then I got the endless login loop thing. I pressed CTRL+ALT+F3 and I ran the command df -h I got as result that my disk was full at 100% and I got no byte left. Then I tried to remove things, I am pretty sure I removed over than 300MB but it still says that I got 0 byte left. I tried it with different users but nothing works. I tried to change the permissions of .Xauthority .ICEauthority and /tmp but these perms are correct. Then I tried to install "lxdm" but I couldn't because I don't have the space left. Please help me, I don't know what to do I cannot use my computer. : / Thanks in advance.


I read on  that the first version of TeX was written in SAIL. However, does anyone know what language later versions (i.e the current one) are implemented in?


When we install a program using apt-get, after installed it's available in terminal, normally, when we just call "your name" independent of context directory we are.  On Windows, when we add a path to envoriment variables in variable PATH all programs or files in this path are available in terminal (prompt command) to be called.  In Ubuntu, how does it when we want to make a program callable but it is a standalone file installed without apt-get or aptitude?


How can I find elements with attributes within a list?

How can I find the elements with different attributes with lxml on python ?  for example  <Form>     <Subform ind="0">         <Check ind="0">0</Check>         <Check ind="1">1</Check>         <Check ind="2">2</Check>         <Check ind="3">3</Check>     </Subform> </Form>   to retrieve the Checks I do:  tree.findall("./Form/Subform/Check")   to get the first:  tree.findall("./Form/Subform/Check[@ind='0']")   but what I want to do is something like  tree.findall("./Form/Subform/Check[@ind='0' or @ind='1']")   To retrieve the first and second only (or first and last)  How can I do that with lxml ?


Planar Realization of a Graph in Three-Space

We call a planar graph one that we can draw in two-space such that no two edges intersect. I was told that we're not so interested in drawing graphs in three-space, because it is "intuitively obvious" that we can just arrange the points and edges in a non-intersecting way because three-space gives us a great deal of room for arrangement.  While I agree that it seems intuitively true, I don't think it's necessarily true: it seems to me as if it might be possible to create a graph for which we cannot conceive a planar realization in three dimensions. If not, can we develop a formal proof that all graphs have a planar realization in three-space?


What to use to store password String or Char[]

I read the following article in Java (Why charcter array is better choice than string for storing password)  1) Since Strings are immutable in Java if you store password as plain text it will be available in memory until Garbage collector clears it and since String are used :in String pool for re-usability there is pretty high chance that it will be remain in memory for long duration, which pose a security threat. Since any one who has access to memory dump can find the password in clear text and that's another reason you should always used an encrypted password than plain text. Since Strings are immutable there is no way contents of Strings can be changed because any change will produce new String, while if you char[] you can still set all his element as blank or zero. So Storing password in character array clearly mitigates security risk of stealing password.  2) Java itself recommends using getPassword() method of JPasswordField which returns a char[] and deprecated getText() method which returns password in clear text stating security reason. Its good to follow advice from Java team and adhering to standard rather than going against it.  3) With String there is always a risk of printing plain text in log file or console but if use Array you won't print contents of array instead its memory location get printed. though not a real reason but still make sense.  String strPassword="Unknown"; char[] charPassword= new char[]{'U','n','k','w','o','n'}; System.out.println("String password: " + strPassword); System.out.println("Character password: " + charPassword);   OutPut:  String password: Unknown Character password: [C@110b053  Question: Relating to the above article how it works in .Net, is it the same or something else, Could someone please give me in-depth knowledge of String and char, how they work?


I am trying to find a short story involving an alien race of 'Intellectuals.' They possess no opposable thumbs or other limbs to control their world.  I think the basis of the story is their discovery of a way to influence another unintelligent species that can manipulate objects.  This leads to a new start for them.  They may have been at risk of breeding beyond available resources.  The story ends with explorers returning from sea. They may have discovered a new land into which they can expand. The last few scenes have a darker flavor where one character has been presented with a rock that glows in the dark. He considers it for a period before being called away to greet the explorers. The author then takes over and makes some comments about most species passing one crossroads only to meet another.  The story could have been written at any time from the Golden Age though to the 1970's.


We have an application running on Windows Server 2008 R2 with Apache WAMP, Tomcat, Mysql, PHP and java SE for last 4 years. Its a Web based ERP application.   I would like to know if it makes sense to migrate this application to CENTOS ( or any other linux variant) and what will be the tradeoff or benefits and if we will encounter any technical issues?


Generating a globally unique identifier in Java

Summary: I'm developing a persistent Java web application, and I need to make sure that all resources I persist have globally unique identifiers to prevent duplicates.  The Fine Print:   I'm not using an RDBMS, so I don't have any fancy sequence generators (such as the one provided by Oracle) I'd like it to be fast, preferably all in memory - I'd rather not have to open up a file and increment some value It needs to be thread safe (I'm anticipating that only one JVM at a time will need to generate IDs) There needs to be consistency across instantiations of the JVM.  If the server shuts down and starts up, the ID generator shouldn't re-generate the same IDs it generated in previous instantiations (or at least the chance has to be really, really slim - I anticipate many millions of presisted resources) I have seen the examples in the EJB unique ID pattern article.  They won't work for me (I'd rather not rely solely on System.currentTimeMillis() because we'll be persisting multiple resources per millisecond). I have looked at the answers proposed in .  My concern about them is, what is the chance that I will get a duplicate ID over time?  I'm intrigued by the suggestion to use  for a , but again, the chances of a duplicate need to be infinitesimally small. I'm using JDK6


StandardSetController with History records

I recently found out that the StandardSetController can't be used with any of the History records such as MyCustomObject__History. The exception I got was:     List controllers are not supported for MyCustomObject__History   The thing is, given this limitation, what would be the best solution to implement pagination? The most inmediate one would be to implement my own pagination solution, but I'm wondering if Salesforce has any other options.


Can someone fix the broken links in this historically-locked question?

This contains some broken links:    But it can not changed, because it is locked.  Can someone fix this?


How do I echo and send console output to a file in a bat script?

I have a batch script that executes a task and sends the output to a text file.  Is there a way to have the output show on the console window as well?  For Example:  c:\Windows>dir > windows-dir.txt   Is there a way to have the output of dir display in the console window as well as put it into the text file?


How do you set the title of the active gnome-terminal from the command line?

Is there a way to set the gnome-terminal title from within the terminal itself without having to right click on the tab. Something like:  active-terminal --title "Foo"   There was a related question previously with an answer that almost lets you do this:  but that doesn't set the gnome-terminal tab title only the window title.


How to create subfloat figures (two in first row and one below)?

I want to place three figures like this on the page:  (a) (b)   (c)   How do I achieve this using subfloat or any other method in LaTeX? The three figures need to have a common caption and label.  I have tried this:  \begin{figure}[h] \centering \begin{tabular}{c c} \subfloat[] { \includegraphics[scale=0.4]{1.pdf} } & \subfloat[] { \includegraphics[scale=0.4]{2.pdf} } \\ \multicolumn{2}{c} \subfloat[] { \includegraphics[scale=0.6]{3.pdf} } \end{tabular} \caption{Some caption} \label{some-label} \end{figure}   But, this is displaying [] for the third figure instead of (c). Also it displays [] to one side of the page instead of center.


An electric circuit is considered a closed circuit if there are two wires connecting to a load, namely live wire and neutral wire. Therefore someone would get electrocuted by touching live wire or neutral wire. However some technicians said that it's safe to touch neutral wire because it contains no electricity, is it true?


I host three different websites on the same server. Here's excerpts from this morning's Apache logs:  ### SITE 1 ### [Fri Dec 13 09:15:49 2013] [error] [client 85.17.87.36] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php.cgi [Fri Dec 13 09:15:49 2013] [error] [client 85.17.87.36] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php4 [Fri Dec 13 09:23:21 2013] [error] [client 113.53.238.155] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php [Fri Dec 13 09:23:22 2013] [error] [client 113.53.238.155] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php5 [Fri Dec 13 09:23:22 2013] [error] [client 113.53.238.155] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php-cgi [Fri Dec 13 09:23:23 2013] [error] [client 113.53.238.155] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php.cgi [Fri Dec 13 09:23:24 2013] [error] [client 113.53.238.155] script not found or unable to stat: /var/www/vhosts/site1.com/cgi-bin/php4 [Fri Dec 13 09:47:03 2013] [error] [client 172.246.127.26] File does not exist: /var/www/vhosts/site1.com/httpdocs/install [Fri Dec 13 09:47:08 2013] [error] [client 172.246.127.26] File does not exist: /var/www/vhosts/site1.com/httpdocs/phpbb3  ### SITE 2 ### [Fri Dec 13 09:24:39 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site2.com/cgi-bin/php [Fri Dec 13 09:24:39 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site2.com/cgi-bin/php5 [Fri Dec 13 09:24:39 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site2.com/cgi-bin/php-cgi [Fri Dec 13 09:24:39 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site2.com/cgi-bin/php.cgi [Fri Dec 13 09:24:40 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site2.com/cgi-bin/php4  ### SITE 3 ### [Fri Dec 13 09:24:40 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site3.com/cgi-bin/php [Fri Dec 13 09:24:40 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site3.com/cgi-bin/php5 [Fri Dec 13 09:24:40 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site3.com/cgi-bin/php-cgi [Fri Dec 13 09:24:40 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site3.com/cgi-bin/php.cgi [Fri Dec 13 09:24:40 2013] [error] [client 107.20.169.255] script not found or unable to stat: /var/www/vhosts/site3.com/cgi-bin/php4   As you can see, some attackers are probing for the existence of software that might be installed on the server, perhaps to search for exploits. I see things like this all the time. One concern is that these logs don't indicate when they were successful. And, in one case, the same IP address is even probing two different sites at the same time. This time the requests seem to be coming from clouds, but that is not always the case.  When the IP address is from places like China or Russia, I manually deny the entire range and restart Apache. But when IP addresses are in the USA, I can't deny the entire range because they could theoretically be used by legitimate customers.  I don't know if this is possible, but I'd like to dynamically block an IP address when certain URL paths are requested.  For example, an IP address would automatically be denied if it requested /cgi-bin/php-cgi  The deny could be temporary in nature. Apache would automatically handle this without requiring a restart.  Is anything like this possible?


I have got my working holiday visa. Before I enter the Schengen area, can I cancel it? If I cancel it, will it become a problem? (i know it would be recorded).  So, if I cancel it, can I still use my 3-month free visa to entry Schengen countries? Also, is it a bad idea to let it expire ? Thanks.


prove there is a bijection between $(0,1)$ and $[0,1)$

I'm completely lost, and I haven't been able to get anything yet. I looked at some that were similar to this problem, and still got pretty lost.


Concatenate a single column into a comma delimited list

I've seen multiple examples of people rolling up a single column into a comma delimited list, but I need a bit more.  Here is an example of the data and results I need.  DECLARE @SalesPerson table (SalesPersonID int, SalesPersonName varchar(10)) DECLARE @Region table (RegionID int, RegionName varchar(15)) DECLARE @SalesPersonRegion table (SalesPersonID int, RegionID int)  INSERT INTO @SalesPerson (SalesPersonID, SalesPersonName) VALUES (1,'Jeff')  INSERT INTO @SalesPerson (SalesPersonID, SalesPersonName) VALUES (2,'Pat')  INSERT INTO @SalesPerson (SalesPersonID, SalesPersonName) VALUES (3,'Joe')   INSERT INTO @Region (RegionID, RegionName) VALUES (1,'North')  INSERT INTO @Region (RegionID, RegionName) VALUES (2,'South')  INSERT INTO @Region (RegionID, RegionName) VALUES (3,'East')  INSERT INTO @Region (RegionID, RegionName) VALUES (4,'West')   INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (1,1) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (1,2) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (1,3) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (2,2) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (2,3) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (2,4) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (3,1) INSERT INTO @SalesPersonRegion (SalesPersonID,RegionID) VALUES (3,4)   A simple select will get me each sales person, with each of that salesperson's region.  SELECT      sp.SalesPersonID,     sp.SalesPersonName,     r.RegionName FROM @SalesPersonRegion spr     JOIN @SalesPerson sp         ON spr.SalesPersonID = sp.SalesPersonID     JOIN @Region r         ON spr.RegionID = r.RegionID    In this case, it will return 9 Rows.  I would like to get results like this:  SalesPersonID    SalesPersonName      Regions 1                Jeff                 North,South,East 2                Pat                  South,East,West 3                Joe                  North,West


Getting "Undefined control sequence" error

When I'm trying to compile a bibliography, I keep getting the "undefined control sequence" error. I'm guessing this is due to some problem in the bib file, but I can't figure out what's wrong with it.   Tex code:  \documentclass[man]{apa6} \usepackage[american]{babel} \usepackage{csquotes} \usepackage[style=apa,sortcites=true,sorting=nyt,backend=biber]{biblatex} \DeclareLanguageMapping{american}{american-apa} \addbibresource{ref2.bib} \usepackage{setspace} \title{ORT} \shorttitle{Ortho} \author{name} \affiliation{univ name} \leftheader{surname} \authornote{None} \abstract{None} \listfiles  \begin{document} Blah blah blah \parencite{Smith1999} \printbibliography \end{document}   Bib entry:  @article{Smith1999, author = {Smith, Bob}, journal = {Journal}, number = {1}, pages = {47--84}, title = {{Article Name}}, volume = {14}, year = {1999} }   I keep getting the error  ! Undefined control sequence. <argument> \printdateextralabel   l.20 \end          {document} ?    What am I doing wrong?


Most of the screenshots on privileges pages are outdated. Shouldn't they be replaced with screenshots of the new design?    Example 1: :  Current Image    Updated Image      Example 2:   Current Image    Updated Image      There are many other screenshots that are also outdated.


I can select entities (or players) who are in a volume easily.  @e[x=0,dx=20,y=0,dy=256,z=20,dz=1]   How do I select all entities who are not in a given volume?    I'm giving players in a certain room a tag, doing stuff with the tag, and want to remove it when they leave.


I have a problem with mouses on my two computers. I will try to describe that issue: When I point some tab in Google Chrome and try to click, it clics a little below... I need to resize Google Chrome window and it works for a while. Second issue is sometimes I can't click on folders on the left corner of desktop. The others folders are OK... Any advices? Regards


I want to run a server with user-written scripts. But these scripts should only use one core (which should be the one with the lowest usage because there will be many concurrent scripts). Also I need to limit time and RAM for them.  Is there an easy way to achieve this, or do I need to check which core has the lowest usage and assign it to it via e.g. ulimit?


Defect on profile page: vertical line consisting of zeros

I have no idea what this is nor how to describe it but it looks like a bug to me.   Funny thing is, I tried visiting other users' profile pages but this "error" only appears on iBug's profile page. No idea why.


Has medical progress stopped human evolution?

We can cure many diseases nowadays, and thus the natural selection is very limited. Plus, mankind spent the whole beginning of its existence in almost the same hostile environment, and that's where he evolved the most, whereas our environment is changing very quickly. So, can we say that mankind froze, if not stopped, its own evolution ?


java.lang.NullPointerException Swing GUI on getResource for an ImageIcon

I am a beginner at swing GUI and I am using a macbook pro and Eclipse Luna and my image is in the same folder as my code in finder, but in Eclipse the image doesn't show in the same folder as my code. See:      import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JScrollPane; import javax.swing.SwingUtilities; import java.awt.BorderLayout;  class Frame extends JFrame {     public Frame() {         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         setTitle("Online First Game Image");          //below is where one of the errors are          ImageIcon image = new ImageIcon(this.getClass().getResource("/image.png"));         JLabel label = new JLabel(image);         JScrollPane scrollPane = new JScrollPane(label);         scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);         scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);         add(scrollPane, BorderLayout.CENTER);         pack();    }      public static void main(String[] args) {         SwingUtilities.invokeLater(new Runnable() {            @Override            public void run() {               // where the other error is               new Frame().setVisible(true);            }         });     } }   And Here Is The Error Message:  Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException     at javax.swing.ImageIcon.<init>(ImageIcon.java:217)     at Frame.<init>(Frame.java:13)     at Frame$1.run(Frame.java:26)     at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)     at java.awt.EventQueue.access$500(EventQueue.java:97)     at java.awt.EventQueue$3.run(EventQueue.java:709)     at java.awt.EventQueue$3.run(EventQueue.java:703)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)   As I said, it would be SUPER helpful if someone can help me fix this bug.   Edit: I fixed the problem, and it had nothing to do with the code. It is not a duplicate and was a problem with trying to add an image to the Eclipse directory.


During my study I find a form for gamma function it was $\Gamma (x) = \lim_{n\to\infty} \frac{n! n^{x-1}}{x(x-1)(x-2)........(x+n-1)}$ And then by simplify this limit I get  $$\lim_{n\to\infty} \frac{n^{x-1}}{{x+n-1\choose n}}$$      then I use Stirling's approximation and evaluate the limit to $\ (x-1)! * e^{x-1} * (\frac{n}{n+x-1})^{x+n-1{\over2}}$$ What next I should do to get Gamma function from this limit ?


I'm attempting to do an AJAX call (via JQuery) that will initiate a fairly long process. I'd like the script to simply send a response indicating that the process has started, but JQuery won't return the response until the PHP script is done running.  I've tried this with a "close" header (below), and also with output buffering; neither seems to work. Any guesses? or is this something I need to do in JQuery?  <?php  echo( "We'll email you as soon as this is done." );  header( "Connection: Close" );  // do some stuff that will take a while  mail( 'dude@thatplace.com', "okay I'm done", 'Yup, all done.' );  ?>


I suppose 'the number of' is followed by a singular, but what about the following sentence where they are two subjects:  Both the number of entries and exits is/are high.


How could the USS Bozeman be in the Typhon Expanse?

In Cause and Effect (S5:E18), Picard's Captain's Log states they are charting the Typhon Expanse and the Enterprise-D is "the first Starfleet vessel to chart this unexplored region". This implies it's in one of the more remote regions of Federation space or even outside of the Federation in "International Space" or extremely difficult to navigate to.  Yet the Bozeman was there in the Typhon Expanse but 80-90 years prior to the 24th century. Further, they were only 3 weeks away from their starbase. This is right next door to the Expanse in galactic terms. It seems unlikely in the span of 100 years or however long that starbase has been operational that Starfleet hadn't gone as far as 3 weeks away. (This assumes it took the Bozeman the full 3 weeks to get to the TE and they just got there.)  How can the USS Bozeman be in the Thyphon Expanse when Picard says the Enterprise-D is "the first Starfleet vessel to chart this unexplored region"?


Python -> 2D list changing at every index?

I've created 28 char array seq, and copied it 100 times to other array copies.  Now at each copy I'd like to change one random char to the other one - def mutate(). It works when it is not in "for". When I try to do it for every copy (for i in range (0, 99) ) it changes copy not only at "i" index but every copy (index) in 2D array "copies".  Why it works like this or how to change it? Why it doesn't change only at current index "i"?  import random      def rand():         a = 'ABCDEFGHIJKLMANOPQRSTUWVYZ '         alphabet = list(a)         seq = []         for i in range (0, 27):             seq.append(alphabet[random.randint(0,26)])         copies = []         for i in range (0, 99):             copies.append(seq)         #print (alphabet)         print(copies[10])         s="".join(seq)         return copies, alphabet       def mutate(copies, alphabet):          print(copies[10])         for i in range(0, 99):             tmp = random.randint(0,26)             copies[i][tmp]=alphabet[random.randint(0,26)]             print(copies[10])         print(copies[10])       copies, alphabet = rand()     print(len(copies))     #print(copies[10])     #print(copies[11])     mutate(copies, alphabet)     print(len(copies))


What is the total number of different sets of natural numbers?

I read that the there are uncountably many different sets of natural numbers. How can you prove that?


Show : $\sum\limits_{n=1}^\infty \frac{a_n}{1+a_n}$ is absolutely convergent

Given $\displaystyle \sum_{n=1}^\infty a_n$ is absolutely convergent. Show that $\displaystyle \sum_{n=1}^\infty \dfrac{a_n}{1+a_n}$ also converges absolutely. (If $a_n \neq -1, \forall n \geq 1$ )  I am not sure where to start with this. Any help would be appreciated


I ran the following to upgrade and got the following error sudo do-release-upgrade -d Checking for a new Ubuntu release Upgrades to the development release are only available from the latest supported release.


Can I enter my pass code when in voice over mode?

Is it possible to unlock the iPhone 4s when in voiceover mode?  I need to be able to enter my pass code in voiceover mode.


There likely is an answer for this out there, but unfortunately I have tried for 3-4 hours and cannot get any common solution to work. I am in a situation where I need to run Ubuntu 14.04, and cannot upgrade, but cannot get wifi to work with my laptop. I had initially used Ubuntu 16.04 but was forced to downgrade as I could not get an old version of PHP (5.5.9) to work correctly with Apache2.  $  lspci -knn | grep Net -A2  05:00.0 Network controller [0280]: Intel Corporation Device [8086:24fb]               (rev 10)     Subsystem: Intel Corporation Device [8086:2110]   $ lshw -C network  *-network                       description: Ethernet interface        product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:03:00.0        logical name: eth0        version: 15        serial: 48:ba:4e:41:d4:57        size: 1Gbit/s        capacity: 1Gbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix bus_master cap_list ethernet         physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168h-2_0.0.2 02/26/15 ip=192.168.0.21 latency=0 link=yes multicast=yes port=MII speed=1Gbit/s    resources: irq:130 ioport:3000(size=256) memory:b4104000-b4104fff memory:b4100000-b4103fff   *-network UNCLAIMED    description: Network controller    product: Intel Corporation    vendor: Intel Corporation    physical id: 0    bus info: pci@0000:05:00.0    version: 10    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress cap_list    configuration: latency=0    resources: memory:b4000000-b4001fff   and the wireless-info script   Most solutions to fix this involve updating the kernel. The kernel I am currently running, gotten from:  $ uname -r  4.8.17-040817-generic   Any help is greatly appreciated and thank you for your time.  [edit]  $ rfkill list all  0: hci0: Bluetooth Soft blocked: no Hard blocked: no


Why is my Ubuntu 12.04 not booting after GRUB?

I've seen a lot of similar issues, but none have quite answered my question. To elaborate, I am trying to dual boot Ubuntu 12.04 alongside Windows 8. I am using a linux usb creator to boot linux. I have tried LiliUSB creator, pendrive linux usb creator, and unetbootin. All three have given me the same result. When I select my flash drive from the BIOS to boot into, it successfully shows the GRUB menu. The GRUB menu however, is black instead of purple that I've seen when normally booting Ubuntu. It displays the normal options to, try linux, intall linux, and boot repair. However, if i select any of these options they all result in a black screen and nothing happening. I am trying a new flash drive in a moment to see if this fixes it. If it doesn't though I would still appreciate any advice or answers I can get. If this is a solved issue please redirect me! Thank you!   Also this is marked as a repeat question, but the question it was marked the same as was unresolved and all answers that were relevant were graphics driver solutions. Mine was a boot error and was resolved from me digging elsewhere in the askubuntu forum, so technically yes it's repeat, but not to that question, so I hope it gets remarked as a solved answer or re-linked to the appropriate question so others who encounter the same issue which isn't graphics related, might find help in this question.  Extra info on my computer if it helps: ASUS x55c model  intel hd 3000 graphics i3 duo core processor 4gb ddr3 Linux is not installed currently (hence my problem) Currently running: Windows 8


5 odd-numbered taxis out of 9 to 3 airports

A fleet of 9 taxis must be dispatched to 3 airports: three to airport A, five to B and one to C. If the cabs are numbered 1 to 9, what is the probability that all odd-numbered cabs are sent to airport B?   What I have have come up with so far:   Probability the cabs are odd is $\frac59$ Probability they are sent to only airport B is $\frac13$ $\frac59 + \frac13 = \frac89$   Is this the right answer?


Could anyone explain how I write units properly in LaTeX? In the form kg.s^-1. They come out all slanted and squished together when i use math mode and \frac.


I've imported a model from an .obj file. It imports fine, and I can see all the separate mesh objects that make up the model. But when I look at their object properties, all the transforms are the same for each mesh. I'm not really sure how that happened or what's going on; I wouldn't mind, but I'm exporting it via fbx to import into a game and it's screwing that process up somehow. Is there some local/global coordinate distinction I'm missing somewhere?


I want to rename all files within a directory to match the parent folder's name.  Now I've found several results that sort of do what I want, but they all seem to rely on a static filetype, path, format, etc.  I need one that takes any crazy folder name and applies it to any files within, leaving their extension unchanged. I don't want the Parent's Parent's Parent, etc. Just something I can run in a current folder to affect all sub-folders within that folder.  For example:  Folder structure  This.Is.A.Crazy.Name.S00E00.720p | | asdfasdfasdfasdfasdfasdfafs.mkv | | info.nfo | | proof.jpg | You.See.Where.This.Is.Going.14x01.480p.crappo | | video.mp4   Expected result  This.Is.A.Crazy.Name.S00E00.720p | |_This.Is.A.Crazy.Name.S00E00.720p.mkv | |_This.Is.A.Crazy.Name.S00E00.720p.nfo | |_This.Is.A.Crazy.Name.S00E00.720p.jpg | You.See.Where.This.Is.Going.14x01.480p.crappo | | You.See.Where.This.Is.Going.14x01.480p.crappo.mp4   Could anyone advise how this can be done in a script or a single, long command?


I want to write down some notes in a .bat file. What codes can be added to the notes so that they will not be treated as commands to be run?


Is there a W3C valid way to disable autocomplete in a HTML form?

When using the xhtml1-transitional.dtd doctype, collecting a credit card number with the following HTML  <input type="text" id="cardNumber" name="cardNumber" autocomplete='off'/>   will flag a warning on the W3C validator:     there is no attribute "autocomplete".   Is there a W3C / standards way to disable browser auto-complete on sensitive fields in a form?


That restaurant can't be very good.      No, it's always empty.   If the second phrase is an agreement, why is there "no", but not "yes"?  I'm thinking it's possible to use both, but "yes" seems more correct.  I didn't find enough examples to understand it.


How can I achieve colour overlay effect in PS?

I am trying to achieve the color overlay effect on a image. I have tried Gradient Map, black and white, a new layer with fill color and reduced opacity. But none are giving the best result. What will be the best way to achieve this effect?


Do we have to tune the number of trees in a random forest?

Software implementations of random forest classifiers have a number of parameters to allow users to fine-tune the algorithm's behavior, including the number of trees $T$ in the forest. Is this a parameter that needs to be tuned, in the same way as $m$, the number of features to try at each split (what Leo Breiman calls mtry)?


When I want to execute a php file it's displayed as text in my browser.  I have a VPS at Hostinger I installed Ubuntu 18.04 with Webmin and LAMP(installed automatically).  I checked the installation see below.  apache2 - v and php -v gives me: Apache/2.4.29 and PHP 7.2.24-0ubuntu0.18.04.6  So everything seem to be installed correctly.  My default folder is /var/www/html/ I do not us short tag in my code.  I try to lunch a file called phpinfo.php with content:  <?php phpinfo(); ?>   And plain text appear on the page.  If the file begin with html code it's correctly rendered, even with a .php file. But the php part is not executed. e.g:  <!DOCTYPE html>         <meta charset="utf-8">     <title></title>
Hello
      <?php phpinfo(); ?>   Render :  Hello  But  <?php phpinfo(); ?>  <!DOCTYPE html>         <meta charset="utf-8">     <title></title>
Hello
       Render the code as plain text.


Total value of coin flips based on heads or tails

First, yes I have researched this question. Yes, I have seen similar things, and have had no problem with that, but this is an added twist and I'm a bit confused. So this is what I'm trying to do:     For each iteration of the loop, toss all coins. If a coin comes up   heads then add the value of the coin to the balance. If a coin comes   up tails then subtract the value of the coin from the balance. After   all iterations, display the balance and the number of seconds it took   to execute the loop formatted to three decimal places.   Coin.java class  import java.util.Random;   public class Coin {  private String sideUp; private Random headORtail = new Random();  public Coin() //no-arg constructor to determine what side of the coin is facing up { toss(); //calls the toss method }    public Coin(String whatSide) //parameterized constructor to set initial side of coin  { sideUp = whatSide; }    public void toss() //simulates coin toss { int num = headORtail.nextInt(2); //random number in the range of 0 - 1  if(num == 0) { sideUp = "Heads"; //0 for heads } else { sideUp = "Tails"; //1 for tails }  }    public String getSideUp() //returns value of sideUp { return sideUp; }   }   CoinDemo.java     import java.util.Scanner;  public class CoinDemo {     public static void main(String[] args) {  //uses parameterized constructor to allow the programmer to set the initial sideUp Coin penny = new Coin("Tails");  //uses no-arg constructor to create coin objects Coin nickel = new Coin();  Coin dime = new Coin();   Coin quarter = new Coin(); Coin half = new Coin(); Scanner keyboard = new Scanner(System.in); //Creates a new scanner to allow user to enter input    System.out.println("Please enter the the number of coin flips to be performed.\nMust be greater than 0: "); int numFlips = keyboard.nextInt();  //Stores the user input into numFlips    //Validation loop checks value entered while (numFlips <= 0) { System.out.println("\n\t~~~ERROR~~~"); System.out.println("The number entered must be greater than 0, please try again."); System.out.println("\t~~~~~~~~~~~\n");     System.out.println("Please enter the the number of coin flips to be performed. Must be greater than 0: ");     numFlips = keyboard.nextInt(); //stores the user input into numFlips }    long totalTime = System.currentTimeMillis(); //Once valid number is entered start the timer  double totalCoin;    for (int i = 0; i < numFlips; i++) //for loop to increment until equal to user entered numFlips {      //calls the Coin object's toss method and stores result in their respective instance variables penny.toss(); nickel.toss(); dime.toss(); quarter.toss(); half.toss();    }  } }   My understanding is that after for example penny.toss(); executes in the loop it will either store the string "Heads" or "Tails" in the instance variable penny. So I tried to use   if (penny == "Heads")  { totalCoin += 0.01; }  else  { totalCoin -= 0.01; }   I'm not sure how else to go about this. I'm fairly new to programming, so please understand I'm trying to learn. That's why I'm here asking for help to understand how to do this.


Cardinality of all equivalence relations on N

I haven't been able to prove that the cardinality of the set of all equivalence relations on N is equal to 2^N. I think that there's probably a bijection between the set of all equivalence classe on N and P(N) but I can't find it. Would apreciate some help.


I am trying to install mysqlclient. I have searched on the internet and found two commands sudo pip3 install mysqlclient or simply, pip3 install mysqlclient. Which one should I use and why?


Minecraft 1.13.1 Inventory Count NBT Tag

I was trying to detect whether a player had a certain amount of items in their inventory. I can detect if a player has an item in their inventory like this: /execute as @a[nbt={Inventory:[{id:"minecraft:command_block"}]}] run say hi  But I thought there was a Count tag too. So I tried this, but it doesn't work: /execute as @a[nbt={Inventory:[{id:"minecraft:command_block",Count:5}]}] run say hi  Is there a way to make this work?


Distance between two vectors: Vector Calculus

I have a parametric equation   x= 24 sin (2πt) y= -24 cos(2πt)+35  This parametric equation is related to a diagram of a Ferris wheel, and is the equation of motion of a point A on the diagram which is attached.    I need to find the cartesian equation of the path of A, since the original equation given on the diagram is a parametric equation and find the distance between O and A when t=0.25.  I have found the cartesian equation and it is , but I don't know how to find the distance between O and A on the diagram (A is one of the smaller double Ferris wheel). Do I assume that since O is stationary it is on the origin of the plane, and I just work out how far away from the origin is A at t=0.25, or am I just approaching this wrong? It has been a long time since I have done vectors, so I am sorry if I sound completely wrong. Has the distance formula got anything to do with it?  Then next I have to state the position vector of point B at time t minutes. I have no idea how to approach this, so this will be of additional help.  Correct me if I am wrong in my thinking somewhere.  Thanks


Is there something wrong with my query?  function needExport($table, $key, $id, $stamp) {     try {         $dbW = dbConCC();         $stmt = $dbW->prepare("SELECT * FROM :table LIMIT 10");         $params = array(':table' => "tmlaender");         $stmt->execute($params);         while ($row = $stmt->fetch()) {             echo $row;         }     }     catch(PDOException $e) {         echo json_encode($e->getMessage());     } }   I get the follwoing Syntax Error:  "SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''tmlaender' LIMIT 1' at line 1"   Can't find any mistakes in this "simple" query.


I get this error when I try to join Hypixel, a Minecraft server. I just updated to Windows 10.I'm not using any mods at all. Here's the crash report:  Completely ignored arguments: [--nativeLauncherVersion, 301] [19:45:31] [Client thread/INFO]: Setting user: Wombatorks [19:45:34] [Client thread/INFO]: LWJGL Version: 2.9.4 [19:45:35] [Client thread/INFO]: Reloading ResourceManager: Default [19:45:35] [Sound Library Loader/INFO]: Starting up SoundSystem... [19:45:36] [Thread-5/INFO]: Initializing LWJGL OpenAL [19:45:36] [Thread-5/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org) [19:45:36] [Thread-5/INFO]: OpenAL initialized. [19:45:36] [Sound Library Loader/INFO]: Sound engine started [19:45:38] [Client thread/INFO]: Created: 1024x512 textures-atlas [19:45:53] [Client thread/INFO]: Connecting to mc.hypixel.net., 25565 [19:45:57] [Client thread/INFO]: [CHAT]                           [19:45:57] [Client thread/INFO]: [CHAT]                           [19:45:57] [Client thread/INFO]: [CHAT] Wombatorks joined. # # A fatal error has been detected by the Java Runtime Environment: # #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ffd55e62177, pid=8508, tid=4976 # # JRE version: Java(TM) SE Runtime Environment (8.0_25-b18) (build 1.8.0_25-b18) # Java VM: Java HotSpot(TM) 64-Bit Server VM (25.25-b02 mixed mode windows-amd64 compressed oops) # Problematic frame: # C  [ig75icd64.dll+0x12177] # # Failed to write core dump. Minidumps are not enabled by default on client versions of Windows # # An error report file with more information is saved as: # C:\Users\Locke\AppData\Roaming\.minecraft\hs_err_pid8508.log # # If you would like to submit a bug report, please visit: #   http://bugreport.sun.com/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # AL lib: (EE) alc_cleanup: 1 device not closed Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release


Best way to auto-restart mono process after crash

I'm on a shared sever without sudo.  I'm using a program running off mono that crashes frequently on a Debian server.  What's the best way to have the process auto-restart?